Dissertations / Theses: 'Olfactory ensheathing cells'

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Miller, Sophie. "The development of olfactory ensheathing cells." Thesis, University of Cambridge, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709275.

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Goodman, Melba Nadine. "Interactions between olfactory bulb astrocytes, ensheathing cells and olfactory sensory neurons." Case Western Reserve University School of Graduate Studies / OhioLINK, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=case1060869724.

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3

Kueh, J. L. L. "Clinical neural scaffold engineering for olfactory ensheathing cells." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1346460/.

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Transplantation of olfactory ensheathing cells (OEC) is one of the most promising current approaches to repair spinal cord injury. The encouraging results from transplantation of OECs in animal models have led to several clinical applications of these cells in spinal cord injury. The first controlled clinical trial was carried out by Mackay-Sim, Féron and colleagues (Mackay-Sim et al., 2008). A number of neurosurgical teams have also implanted foetal OECs (Huang et al., 2003) or minced whole mucosal tissue (Lima et al., 2006) into spinal injuries. So far the reported functional benefits are only moderate. The Mackay-Sim team reported no improvements while others reported minor improvements (including an ongoing trial by Pawel Tabakow’s team in Poland; personal communication). The basic conclusion is that OEC transplantation is feasible and safe. However, in the studies where suspensions of OECs were used there were not enough cells to fill the lesion, and no materials were used to bridge the gaps. In order to progress to more effective transplants the two areas addressed in this thesis will be important – what is the best source of adequate numbers of cells, and what biomaterials can be used to bridge the gaps. In addressing the twin necessities of (a) identifying the tissue source needed to provide sufficient cells for transplantation and (b) the problem of bridging the large gaps present in spinal cord injuries, the results of this study were directed towards two issues. (a) The questions of cell source and proliferation were addressed by establishing the quantitative baseline for the yield of primary cultures from the olfactory bulb, and the whole and split olfactory mucosa and characterising the heterogeneity of these cultures in search for any difference between bulbar and mucosal OECs. The study of flow cytometric simultaneous antigenic bivariate cell cycle of purified OECs and ONFs from these four sources revealed the evolution of population heterogeneity and its strikingly differences between these four sources of primary tissue with additional populations that were not previously described. An unexpected highly proliferative p75+ population in the stripped mucosal epithelium was also characterised. Correlation study of the cell proliferation and population evolution revealed cell autonomous among the difference sources. (b) The feasibility of a synthesis biomaterial for the deployment of OECs and olfactory nerve fibroblasts (ONFs) as a transplant was addressed by designing and developing an electrospun PLGA nanocomposite nanofibre construct with a myriad of microfabrication techniques, focusing on how OECs and ONFs can be deployed during tissue culture and transplantation. The techniques included nanocomposite electrospinning, replica moulding from photolithographed silicon mould, design of tissue-culture membrane insert, and laser ablation. The biocompatibility study showed that when grown on a fibre mesh structured at the nano-scale, OECs responded by adopting the elongated form comparable to that which occurs when the convey regenerating fibres cross small lesions in in vivo transplants. Preliminary functional studies of using the nanocomposite nanofibers as a neural scaffold in the organotypic entorhino-hippocampus slice co-culture data provide an indication that the nanofibres are compatible with tissue and allow migration of astrocytes and growth of nerve fibres. These observations will be important in future attempts to derive larger cell populations for transplantation. The anticipated use of the OEC nanofibre prosthesis would be in the application of autologous human OECs for bridging the gap in spinal cord lesions.

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Franceschini, Isabelle A. "Cellular and molecular studies on olfactory bulb ensheathing cells." Thesis, University of Glasgow, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301803.

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Perera, Surangi Nalika. "Olfactory ensheathing cell development : a transcriptome profiling approach." Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/288787.

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Olfactory ensheathing cells (OECs), the glia of the olfactory nerve, are promising candidates for patient-specific cell-mediated repair of both peripheral nerves and the spinal cord. The recent discovery that OECs originate from the neural crest, rather than the olfactory epithelium as previously thought, potentially means that homogeneous populations of OECs for repair could be expanded in culture from neural crest stem cells persisting in the patient's own skin and hair follicles. The first step towards this long-term goal is to understand the molecular mechanisms underlying neural crest differentiation into OECs, as opposed to Schwann cells (the glia of all other peripheral nerves), which are less effective in spinal cord repair. To identify transcription factors and signalling pathways that might be involved in OEC versus Schwann cell differentiation, I took an unbiased transcriptome profiling approach. Taking advantage of Sox10 expression throughout both OEC and Schwann cell development, I used laser-capture microdissection on cryosections of mouse embryos carrying a Sox10:H2BVenus transgene, to isolate OEC subpopulations (olfactory mucosal OECs, from the olfactory nerve, and olfactory nerve layer OECs, from the olfactory nerve layer surrounding the olfactory bulb) at different stages of development, and Schwann cells from trigeminal nerve branches on the same sections, for RNA-seq and cross-wise comparison of transcriptomes. Validation of candidate genes by in situ hybridisation revealed some contamination with adjacent cells from mesenchyme, olfactory epithelium or olfactory bulb, but also identified the expression in developing OECs of various genes previously reported to be expressed in adult OECs, and of over 20 genes previously unknown in OECs. Some of these genes are expressed by OECs but not Schwann cells; some are expressed by olfactory nerve layer OECs but not olfactory mucosal OECs, while some are expressed by olfactory mucosal OECs and Schwann cells but not olfactory nerve layer OECs. For a subset of the genes, I was also able to analyse OEC differentiation in mouse mutants. I also collected transcriptome data from neural crest-derived cells that persist on the olfactory nerve in Sox10-null embryos (in which neural crest-derived cells colonise the olfactory nerve, but normal OEC differentiation is disrupted). Comparison with wild-type OEC transcriptome data from the same embryonic stage identified genes whose expression is likely either downregulated or up-regulated in the absence of Sox10, supporting a role in normal OEC differentiation. Overall, these various transcriptomic comparisons (between OECs at different developmental stages, different OEC subpopulations, OECs versus Schwann cells, and OECs versus Sox10-null neural crest-derived cells on the olfactory nerve) have identified multiple transcription factor and signalling pathway genes, amongst others, that are expressed during OEC development in vivo (including some specific to different OEC subpopulations) and that may be important for OEC differentiation. Furthermore, some of these genes are not expressed by embryonic Schwann cells. This work provides a foundation for understanding how to promote OEC rather than Schwann cell differentiation from neural crest stem cells in culture, with the potential for clinical application in the future.

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Fjelldal, Marthe Fredheim. "Study of Rat Olfactory Ensheathing Cells in Alginate based Matrices." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for bioteknologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-16803.

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Alginate hydrogel made from alginate and crosslinking divalent ions is a natural biomaterial that is biocompatible, has low toxicity, is relatively cheap and has mild gelation chemistry. It is a porous material that allows diffusion of small molecules. Alginate hydrogel is a polymeric network that contains 95-99% water and it does in many ways resemble the natural extracellular matrix (ECM) that surrounds cells in the body. It is also hydrophilic, which reduces friction in body fluids and minimizes protein adsorption and it is easily stored and sterilized.Alginate is produced by both algae and bacteria, and it is initially synthesized as mannuronan (M) with 100% M-residues. Guluronic acid residues (G) are introduced in a post-polymerization step by enzymes called mannuronan C-5 epimerases that catalyze conversion of M into G without breaking the glycosidic bond. Seven different mannuronan C-5 epimerases have been sequenced, cloned and produced recombinantly, and these enzymes introduce MG-blocks, G- blocks or both in the alginate chains. With the use of these mannuronan C-5 epimerases it is now possible to engineer alginate with desired and known structure. It is also possible to covalently modify alginates with coupling of cell specific adhesion molecules to the carboxylic group in the monomers. An example is the RGD peptide (arginine-glycine-aspartic acid) that is commonly found in collagen and fibronectin in the ECM. The RGD peptide is the smallest sequence that integrin receptors can recognize and bind to.Central nervous system (CNS) damage is still one of the major causes of both death and disability, despite intense research efforts to achieve neurogenesis and restore functional synaptic connection of CNS neurons. None of he current therapy strategies promote regeneration or regrowth of neural cells or axons. In vitro and in vivo studies has shown that CNS axons can regenerate when located in a permissive environment and it is known that on-going neurogenesis occurs in certain areas of the adult brain, such as the olfactory bulb. Olfactory ensheathing cells (OECs) are found in the olfactory mucosa and olfactory bulb and secrete neurotrophins, provide necessary ECM molecules and substrates for axon elongation and myelination. They do not activate and induce inhibitory molecules or hypertrophy in astrocytes, and are therefore believed to be a promising candidate for cell-mediated repair of the CNS.The major aims of this study was to investigate whether encapsulation of OECs in different types of alginate matrices would improve cell viability over time and induce change of cell morphology, as a future goal is to transplant OECs into the CNS. Viability of OECs up to 14 days in 1.8% UP-LVG capsules have been reported by Kristin Karstensen (Karstensen, 2010), and similar results were achieved in an experiment in this project. Indications of cell concentration dependency on viability were observed in this experiment, with higher viability in capsules with low cell concentration (1.5 mil cells/mL alginate, 3.0 and 5.0 mil/mL). It was decided to conduct an encapsulation of high and low OEC concentration (4.0 mil/mL and 1.0 mil/mL) in 1.0% UP-LVG Ca2+/Ba2+ alginate, with the aim of examining whether reduced alginate concentration would improve cell viability. The results were promising, with a live cell percentage of 50% in the low cell concentration batch after 51 days. The high cell concentration batch was discarded after 22 days with estimated 30% live cells. This result strengthened the hypothesis that lower cell concentration enhanced cell viability, and confirmed that lower alginate concentration improved cell viability notably. These indications were supported by the results of a second encapsulation with similar settings. High and low concentrations (1.5 mil/mL and 5.0 mil/mL) of OECs were encapsulated in 1.0% epimerized Ca2+ alginate with and without 0.2 % RGD peptide graft. The experiment did not show an effect of the RGD peptide on cell viability or morphology. The viability of the cells was extended with one week and viable cells could be observed for 22 days, but in this experiment increased viability as a result of lower cell concentration was less pronounced. This experiment was therefore inconclusive in terms of improved viability connected to cell concentration, but indicated that a lower alginate concentration had a beneficial impact on cell viability. Star shaped channels were observed inside all capsules in this experiment, and a large fraction of dead cells were found to be located inside these channels. This experiment was later repeated with another source of epimerized alginate grafted with ≈ 0.4% RGD peptide with comparable results in terms of cell viability and morphology.Two encapsulations of low cell concentration in 1.0% UP-LVG Ca2+/Ba2+ alginate mixed with three different concentrations of gelatin (0.5%, 1.0% and 2.0%) were carried out, with the aim of observing capsule stability and cell viability. In first experiment the capsule stability appeared to be inversely proportional with gelatin concentration. This was not confirmed when the experiment was repeated, as the batch with the middle gelatin concentration was perceived as most stable. The cell viability was overall high for both encapsulations. Finally, four batches of 1.5 mil/mL OECs were encapsulated in 0.9% UP-LVG Ca2+/Ba2+ alginate gel with one type of ECM molecule mixed with the alginate per batch to yield a concentration of 1.0 mg/mL. Sulphated MG alginate was mixed with 0.9% UP-LVG Ca2+/Ba2+ alginate to a final concentration of 1.0 mg/mL, and included in the experiment. The experiment was terminated at day 28, with varying cell viabilities in the different batches. Common for all was overall lower cell viability compared with the viability observed for cells with similar concentration encapsulated in pure 1.0% UP-LVG, but the capsules proved to be relatively stable. In conclusion, reducing the alginate concentration from 1.8% to 1.0% had notable positive effect on cell viability. High cell concentration in the alginate capsules also proved to have a negative impact on cell viability, but this effect was most evident in the UP-LVG alginate gels. The negative effect on cell viability related to high cell concentration was not as profound in the epimerized alginate gels.RGD peptide grafted onto alginate did not show any unambiguous effect on cell viability and no effect on cell morphology, regardless of 0.2 % peptide graft or ≈ 0.4% peptide graft. The gelatin-1.0% UP-LVG alginate mixes also failed to induce morphology change in the OECs, and neither did any of the ECM molecule-1.0% UP-LVG alginate mixes or the sulphated alginate-1.0% UP-LVG alginate mix. The cells encapsulated in gelatin-alginate mix capsules displayed an overall high viability, while the cells encapsulated in ECM molecule- alginate mix and sulphated alginate- alginate mix displayed lower viability than cells encapsulated in pure UP-LVG alginate. All capsule varieties displayed generally good stability in culture, with the exception of the gelatin-alginate mix capsules that progressively dissolved in culture.

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Cawardine, Darren Rhys. "Engineering canine olfactory ensheathing cells for spinal cord injury repair." Thesis, University of Bristol, 2017. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.738207.

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Cameron, Nicholas John. "Developing Olfactory Ensheathing Cells for ex vivo Delivery of GDNF." Thesis, Griffith University, 2010. http://hdl.handle.net/10072/365205.

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Olfactory ensheathing cells have well described neurotrophic properties and can promote repair of damaged nerves in the central nervous system. Genetically engineering these cells to deliver therapeutic proteins could ‘supercharge’ their existing abilities to repair damaged nerves and prevent neurodegeneration in disease. The present study used retroviral vectors to engineer human olfactory ensheathing cells to co-express the potent neurotrophin GDNF and reporter genes under a tetracycline-inducible promoter. The goal here was to provide proof of concept for using olfactory ensheathing cells (OECs) for controlled ex vivo delivery of GDNF in preclinical studies. Until now, OECs from the olfactory mucosa have not been examined or developed for this purpose. Here a systematic evaluation of OECs revealed their suitability for developing ex vivo gene therapies. Olfactory ensheathing cells from rats and humans were successfully purified from the olfactory mucosa by p75NTR immunopanning and did not express secreted GDNF protein prior to genetic modification. The immunopanning method did not purify putative neural precursors or stem cells from the human source tissue. Lentiviral vectors incorporating bi-cistronic gene expression cassettes directed drug-inducible co-expression of GDNF and reporter gene in transduced OECs. Here for the first time the foot and mouth disease virus 2A cleavage factor was used to co-express GDNF and reporter genes in human OECs. Biological activity of GDNF and reporter genes (EGFP and β-Galactosidase) was not affected by 2A cleavage in transduced OECs. Owing to robust reporter gene expression in these cells, highly purified cultures of drug-inducible and constitutive expressing OECs were isolated by fluorescence activated cell sorting. In the inducible cell lines, more than 20-fold induction of gene expression was seen after treatment with minocycline however, unsatisfactory baseline expression or ‘leakage’ was observed in the absence of minocycline. Cells constitutively co-expressing GDNF and EGFP were then transplanted into the intact rat striatum. After 9 days, transplanted OECs expressed transgenes, but the majority of grafted cells died. Overcoming the poor cell survival and leakage of expression in inducible cells must precede transplanting these cells in animal models of disease. In conclusion, a robust method for co-expressing therapeutic genes in OECs for preclinical ex vivo gene therapy studies was developed using 2A cleavage and lentiviral vectors. The results present a strong case for using OECs as vehicles to deliver therapeutic genes but also highlight shortcomings of drug-inducible gene expression systems.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Biomolecular and Physical Sciences
Science, Environment, Engineering and Technology
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9

Wu, Ann Shang Medical Sciences Faculty of Medicine UNSW. "Olfactory ensheathing cells in a rat model of dorsal root injury." Awarded by:University of New South Wales. Medical Sciences, 2009. http://handle.unsw.edu.au/1959.4/44793.

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The rat model of cervical dorsal root injury mimics the avulsion of dorsal roots in humans following brachial plexus injury, a condition that leads to debilitating sensory disturbances and intractable neuropathic pain that is not amenable to repair. This injury disrupts sensory inputs from the dorsal roots to the spinal cord and the damaged axons do not regenerate across the PNS-CNS interface, the dorsal root entry zone. This thesis investigated the role of OECs for repairing DRI-associated neuropathic pain, which has never been previously explored. Chapter 2 of this thesis characterised two DRI models, a partial (2-root) or complete (4-root) deafferentation of the rat forepaw. The 2-root animals developed persistent allodynia and hyperalgesia, whereas in the 4-root DRI, in contrast, reduced sensation (desensitisation) was found within the affected forepaw. The degree of deficits on performing complex, skilled forepaw movements was proportional to the severity of DRI. Sensory control of forepaw movements was permanently abolishes in animals with 4-root DRI. With the goal of repairing DRI-associated neuropathic pain, the efficacy of genetically modified OECs that carry a novel GDNF construct was examined. These modified GDNF-OECs were able to produce GDNF in vitro, however, died rapidly and failed to yield long term GDNF expression after both acute and delayed transplantation into the DRI spinal cord. Unmodified plain OECs were then used. The results show that delayed transplantation of OECs attenuated the development of DRI-associated allodynia and hyperalgesia. Central reorganisations occurred within the dorsal horn following DRI, including reduction in the area of deep dorsal horn, permanent depletion of IB4-labeled axons and restoration of CGRP-labelled afferents in the denervated superficial laminae. The development of neuropathic pain is suggested to be mediated by the aberrant expansion of large myelinated VGLUT1-positive afferents into the superficial laminae, which normally receive nociceptive inputs. The effect of OECs on modulating nociception seems to be mediated by factors other than inhibition of afferent sprouting. In conclusion, the results in this thesis demonstrated the potential effect of OECs for modulating DRI-associated neuropathic pain. This finding could have clinical applicability for resistant pain sequelae resulting from neurotrauma.

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Nazareth, Lynn. "Determining Cellular and Molecular Mechanisms Behind Glial Cell Phagocytosis." Thesis, Griffith University, 2021. http://hdl.handle.net/10072/408099.

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Phagocytosis (“cell eating”) is an immunobiological process required for maintenance of systemic homoeostasis under normal physiological conditions (during development and adulthood) and in various pathologies. Phagocytosis is a receptor-mediated event, wherein a phagocytic cell recognizes, engulfs and degrades specific targets that need to be eliminated. The targets can be either “self-targets”, such as dead or damaged cells, or “non-self-targets”, such as microorganisms. In the nervous system, the “first responding” phagocytes are usually the supporting glial cells. Based on the location they are present in, glial cells are classified as either CNS or PNS glia. The key phagocytic glia in the CNS are astrocytes and microglia, and in the PNS, Schwann cells (SCs). Some peripheral nerves, however, have other glial types which mediate this function, such as olfactory ensheathing cells (OECs) in the olfactory nerve. Efficient phagocytosis is essential for regeneration after nervous system injury, but after CNS injury, glial phagocytosis is often inefficient. In contrast, after PNS injury, glia rapidly phagocytose and clear the cellular and myelin debris resulting from the injury. Due to their ability to support nerve growth, particularly via physical support and secretion of growth/guidance factors, while simultaneously performing phagocytosis; transplantation of SCs and OECs have promising potential to treat CNS injuries. However, phagocytosis is a highly specialized function and the key molecular and cellular components in PNS glial phagocytosis are largely unknown. If these could be characterized, new drug targets may be revealed that can further promote glial-mediated neural regeneration (but without causing an excessive inflammatory response). The site of a CNS injury is a complex environment, with cell death occurring via different mechanisms. These include distinct types of necrosis and apoptosis, and glia may respond differently to these distinct “self-targets”. Hence, in this Thesis, I investigated key cellular and molecular mechanisms involved in OEC- and SC-mediated phagocytosis of cells undergoing various forms of death. I discovered that OECs and SCs are indeed competent phagocytes that can recognize, internalize and degrade a range of “self-targets”. Both cell types expressed a number of phagocytic receptors, including phosphatidylserine (PS) recognition receptors, pathogen recognition receptors (PRRs), scavenger receptors, Fcγ receptors (FcγRs) and complement receptors (CRs). OECs and SCs both rapidly recognised and engulfed various cellular targets (within 2 h). Recognition of targets occurred mainly via PS displayed on the dying cell surface, with potential involvement of PRRs. The family of small Rho GTPases (Rac, Cdc42 and Rho) were also important for target engulfment. However, while engulfment was rapid, breakdown was relatively slow, particularly when the targets were necrotic bodies and myelin debris (especially when compared to professional phagocytes, i.e., macrophages). Engulfment of apoptotic targets resulted in anti-inflammatory cytokine production, however, necrotic target uptake led to a proinflammatory response. Overall, OECs phagocytosed larger amounts of targets over time, as well as processed targets faster, than SCs. During the process of phagocytosis, OECs also produced less pro-inflammatory, but more immunomodulatory, factors than SCs. Thus, OECs were more efficient in phagocytosing “self-targets” than SCs, accompanied by a more favourable immune response, suggesting that OECs may be better transplantation candidates than SCs. Two peripheral nerves, the olfactory nerve and the trigeminal nerve (intranasal branches) extend between the nasal cavity and the brain. These nerves are populated by OECs and SCs, respectively. These nerves have been shown to function as a pathway by which certain microbes can enter the brain, leading to CNS infection. The nasal mucosa, and associated nasal-associated lymphoid tissue (NALT) constitute a strong physical and immunological barrier against microorganisms, and those that do manage to penetrate the mucosa are considered to be phagocytosed by OECs and SCs in the nerves. However, microbes that can infect the CNS via these two peripheral nerves have been shown to evade phagocytic destruction and instead infect PNS glia. In this Thesis, I also investigated how OECs and SCs respond to bacterium thought to infect the CNS via nerves - Chlamydia muridarum. I chose this bacterium as it is commonly used to model C. pneumoniae infections in mice. C. pneumoniae CNS infection has been suggested to contribute to the development of late-onset dementia, thus being clinically relevant. I found that C. muridarum, which replicates in intracellular inclusion bodies, infected both OECs and SCs, however, the glia were not as susceptible to infection and intracellular bacterial growth as non-immune cells. Both OECs and SCs mounted a significant immune response to bacterial challenge, with OECs producing the strongest response. Despite this, C. muridarum could manipulate various intracellular and phagocytic machinery pathways to survive inside the glia, including pathways involving small Rho GTPases (Rac, Cdc42 and Rho) and PI3K/Akt. C. muridarum also suppressed lysosomal recruitment by “hijacking” Ras-like small GTPases (Rabs) responsible for intracellular trafficking and host nutrient scavenging. Thus, C. muridarum could escape phagocytosis (degradation) and grow inside glia. This is potentially a key reason by which the bacteria may disseminate through peripheral nerves, leading to CNS infection. The findings presented in this Thesis (including resultant publications), increases our understanding of how PNS glia remove dying and damaged “self”, including key cellular and molecular mechanisms involved in OEC and SC-mediated phagocytosis. The current study also, by characterizing how the glia responded to C. muridarum, explored the crucial dichotomy between phagocytosis vs infection. Internalization of bacteria into a cell can lead to either or both. In the case of OECs and SCs, C. muridarum challenge led to infection but also an immune response, restricted bacterial growth and likely also killing of a proportion of bacteria. This understanding may provide us with tools/drug targets for manipulation of various aspects of the PNS glia-mediated phagocytic processes. This could involve improved clearance of cellular debris without adverse inflammatory events post-transplantation into a nervous system injury site. Tweaking certain aspects of the phagocytic pathway may also prevent infections by microbes that can use the nose-to-brain pathway to infect the CNS, without using antibiotics (thus, not contributing to antimicrobial resistance). Finally, this thesis has also given us some interesting insights into differences between the two types of PNS glia. OECs and SCs, were considered to be quite similar in the past and both are deemed as good transplantation candidates. Overall, OECs were found to be more efficient phagocytes and equipped with additional molecular components of phagocytic pathways than SCs. OECs also produced a more favourable immune response than SCs in response to damaged “self”. In contrast, OECs mounted a stronger bactericidal immune response to C. muridarum than SCs, suggesting that OECs exhibit better antimicrobial protection mechanisms than SCs.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Pharmacy & Med Sci
Griffith Health
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11

Lakatos, Andras. "Do olfactory ensheathing cells have advantages over Schwann cells in transplant mediated CNS repair?" Thesis, University of Glasgow, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274787.

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Wood, Rachael Claire. "Bioprocess optimisation improves identity and potency of olfactory ensheathing cells for neurologic regeneration." Thesis, University College London (University of London), 2018. http://discovery.ucl.ac.uk/10047503/.

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The potential application of olfactory ensheathing cells (OECs) to spinal cord injury has been the focus of a lot of research over the past ten years. Currently there are many challenges associated with the use of these cells as a therapy. These include the inherent plasticity of the cells and the fact they are challenging to sustain in culture for prolonged periods due to poor survival and proliferation. They possess unique properties as they are able to support neuronal survival and facilitate the regeneration of severed axons and therefore overcoming these challenges would be a step towards developing a cell therapy for spinal cord injury. Initially rat models were used to determine culture conditions that enhance the protein expression of key OEC markers p75NTR and S100β. An increase in p75NTR expression was achieved by co-culturing the primary rat OECs with a conditionally immortalised immobilised human mucosal fibroblast cell line feeder layer. OECs cultured on feeders were found to adopt a more spindle-like appearance compared with cells cultured on laminin which adopted an enlarged morphology. This morphological change is significant as spindle-shaped OECs are associated with neural regeneration function. Conditioned media collected from the human feeders resulted in an increase in Thy1.1 protein expression, an undesirable marker, with no increase in p75NTR expression and co-culture of primary OECs with mouse feeders (Ms3T3) gave similar results to co-culture with human feeders. It was determined that OECs benefit from the cell to cell contact and not necessarily trophic factors present in the media. The best culture conditions for primary rat OECs were found to be Ms3T3 feeders with DMEM/F12 Glutamax media. Testing with conditionally immortalised human OEC cell lines found contrasting results where an increase in S100β was observed when cells were cultured on laminin and lower levels of expression observed during feeder co-culture. Similarly to primary rat OECs, conditioned media from human mucosal fibroblasts was detrimental to S100β expression. The best culture conditions for human OECs were found to be laminin coated wells with DMEM/F12 Glutamax media. These data sets show that care has to be taken when translating animal models to studies with human cells as the data does not always correlate. Studies continued to characterise optimum culture conditions for the conditionally immortalised human OEC cell line. MACS purification technology was used to remove Thy1 positive cells from the polyclonal population. Although this removal was successful, it was found that the complete removal of Thy1 from the population does not ensure Thy1 is not present in the future population. After 5 days in culture Thy1 was being expressed in the Thy1 negative population. Time point staining determined that Thy1 turns on and off during time in culture and the removal of Triton X from the staining protocol is vital to visualising the presence of this protein. This time point study also revealed p75NTR is not a stable marker for OECs as turns off over time in culture. Further study towards understanding the role Thy1 and p75NTR take in OEC function would be beneficial to development of an OEC cell therapy for spinal cord injury. After the identification of optimum culture conditions for enhanced p75NTR and S100β expression, co-culture with neurons was carried out in order to determine if these conditions would link to an improvement in functional support. Neurite length was measured after 5 days of co-culture and was normalised against the number of neurites and neurons, which is an established method of relating the behaviour of the neurons to functional response after implantation. It was found that conditions that related to higher expression of p75NTR and S100β (laminin coated wells, standard media, shorter time in culture) led to longer and more numerous neurites. From this it can be established that levels of p75NTR and S100β expression are good predictive tools for the extent to which OECs can support neural regeneration in culture. The next step would be to relate the expression of these markers to the myelination of neurons. Thy1 expression was not found to be related to neurite extension and purified populations of negative and positive Thy1 OECs resulted in longer neurites than the original mixed population. This could be due to lateral inhibition but further work is required to confirm this theory. Results described in this thesis have demonstrated that caution needs to be applied when scaling rat studies to human cell work. It has also shown that the method and timing of detecting protein expression can be vital to the results observed. These are key aspects that need to be considered in order to fully characterise cell populations, especially one as variable as OECs. The methods used in this work showed an increase in p75NTR and S100β expression led to longer neurites extended from neurons. Further work should be carried out in order to fully understand the interaction between OECs and neurons and to explain the potential lateral inhibition pattern observed.

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Rayapureddi, S. "Characterisation and application of olfactory ensheathing cells for glaucoma induced optic nerve damage." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1366899/.

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Glaucoma is the term used to describe a group diseases characterised by a specific type of damage to the optic nerve head (ONH) known as cupping and a characteristic type of visual field loss. This loss is associated with progressive atrophy and loss of the retinal ganglion cells. Glaucoma is a leading cause of irreversible blindness in the world. This project was aimed at investigating olfactory ensheathing cells (OEC), a population of radial glia proven to be neuroprotective in central and peripheral nerve injury models, and their potential to protect the retinal ganglion cells in glaucoma. We studied the interactions of RGC and OEC in culture. We show that OEC can straighten, ensheath and bundle RGC neurites as well as support the survival of RGC and their synapses in culture. We also show that OEC endocytose dead RGC in culture. We modified a rat model of glaucoma (where paramagnetic microbeads are injected into the anterior chamber of the rat eyes) and characterised the early and late functional changes in the glaucomatous retina. We showed that RGC function was compromised in the early stages of glaucoma, before histological changes set in. We injected OEC into glaucomatous rat eyes to study the effects of OEC on optic nerve damage. The presence of OEC in the vitreous cavity of the glaucomatous rat eye significantly reduced the optic nerve damage in glaucomatous eyes. In summary, the work presented in this thesis provides an insight into • The functional changes of RGC in the early stages of experimental glaucoma and • Protection of RGC in experimental glaucoma by introduction of OEC into the vitreous.

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McMonagle, Brent Anthony. "Nasal Derived Olfactory Ensheathing and Stem Cells in Peripheral Nerve Repair and Regeneration." Thesis, Griffith University, 2016. http://hdl.handle.net/10072/366095.

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Damaged peripheral nerves are usually surgically repaired in an attempt to optimize recovery. The patient is stabilized and other potential life-threatening problems are managed. The wound area is thoroughly cleaned and devitalized tissue debrided, and any vascular injuries repaired. The nerve ends are trimmed, and if possible, sutured together using fine sutures using standard microsurgical techniques, provided there is no tension. There is often a gap between the ends of a damaged nerve, because of loss of nerve substance by the injury or resection of tumour, as well as retraction of the stumps because of the inherent elasticity of nerves. In certain circumstances, the nerve stumps may be mobilized to gain extra length, or sutured to other neighbouring nerves (see end-to side repair), but generally, a conduit is required to bridge the gap. Various different conduits have been used to bridge this gap in an attempt to allow axons to regenerate across the gap to the distal nerve stump, align and enter the endoneurial tubes of the distal stump, elongate down these tubes, and finally assume a connection with the end-organs (e.g. motor end-plates, sensory receptors, etc.) of their previous peripheral targets.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Natural Sciences
Science, Environment, Engineering and Technology
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15

Choudhury, Indra N. "Enhancing therapeutic potential of olfactory ensheathing cells in spinal cord injury by phagocytosis." Thesis, Griffith University, 2023. http://hdl.handle.net/10072/421686.

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Under normal physiological condition the body needs to fight bacterial infection, clear old dead or dying cells as well as regenerate new ones. Phagocytosis is the immunological process required for cells to digest and destroy particulates thereby maintaining a systemic homeostasis. Phagocytosis involves four steps of recognition, engulfment, formation of phagosome, degradation and elimination. In the nervous system, the phagocytes are the glial cells which support the system framework, primarily microglia. Spinal cord injury is an irreparable nervous system injury and restoration of function is very difficult. One strategy which could aid repair and regeneration is to enhance the phagocytic process thereby removing cell debris and bacteria from the injury site. Glial cells are involved in phagocytosis and clearing the spinal cord injury area. Understanding this process may improve strategies to develop therapy, particularly those that involve cell transplantation such as peripheral nerve glia. Within the nervous system, the main phagocytic glia, which has been studied, in the central nervous system (CNS) are astrocytes and microglia, and in the peripheral nervous system (PNS), the main glia are Schwann cells for most nerves, with olfactory ensheathing cells (OECs) in the olfactory nerve. In this study, my first objective was to compare the CNS and PNS cells like astrocytes, microglia, OECs and trigeminal Schwann cells (TgSCs) for their antimicrobial response to bacterial infection (S. aureus). Results showed live bacteria could be isolated from all glia after 24 h in culture, and microglia, OECs and TgSCs exhibited better protection against intracellular S. aureus survival than astrocytes. All glial types responded to the bacteria by cytokine secretion, but overall, OECs secreted the lowest level of cytokines. Debris clearance is crucial for neural regeneration and OECs have the ability to phagocytose both bacteria and cell debris. OECs and SCs are being considered as cell transplantation therapies in spinal cord injury for the purpose of repairing the damaged nervous system. Thus, understanding the genetic expression in between OECs and SCs during the process of phagocytosis of bacteria (S. aureus) and axonal debris is essential. Results showed OECs responded to S. aureus with protein modification and phosphorus metabolic processes involved with immune response, and leukocyte mediated immunity signalling mechanisms for bacterial engulfment. SCs responded to cell debris with pathways associated with actin filament-based processes, cytoskeleton organization, and FC gamma receptor dependent phagocytosis. These findings demonstrate the differences between OECs and SCs during phagocytic responses to bacteria and cell debris. Overall, OECs expressed a low gene expression profile compared to SCs. Discovering novel compounds that can stimulate OECs to phagocytose bacteria and cell debris more efficiently may improve the therapeutic potential of the cells. Potentially, if OECs could be pre-stimulated with a drug to enhance OEC phagocytosis, that could be useful in spinal cord injury regeneration. Therefore to identify compounds that would enhance the phagocytosis of glial cells, drug discovery assays were performed. Following a preliminary compound screening, a synthetic compound and a natural compound was identified. For a third compound, a FDA approved drug was selected to test their effects on glial cells. As the process and analyses, required to identify compounds, that stimulate glial cell phagocytic activity has not been previously established, development and optimization of a protocol for phagocytosis detection was performed. Phagocytosis measurement in glial cells based on live imaging and fixed widefield imaging was performed to make a replicable drug discovery testing method which could be used on cell lines and primary cells both. Using this method results like cytotoxicity, morphological changes and phagocytosis of various targets can be reliably performed. Testing the compounds with the protocol, demonstrated that significant stimulation of phagocytosis activity could be detected. All three compounds tested showed positive phagocytosis increase on cell lines. The synthetic compound showed positive increase in phagocytosis on primary OECs and TgSCs but not in astrocytes and microglia for S. aureus pHrodo BioParticles. Testing further, using the synthetic compound, in the presence of bacterial stimulus, showed no significant upregulation in cytokines but some positive upregulation in phagocytotic genes, in the compound stimulated wells against controls. The natural compound showed increase in phagocytosis only in microglia but not in other glial cells (OECs, TgSCs and astrocytes). The FDA compound Liraglutide showed significant increase in phagocytosis in all glial cells (astrocytes, microglia, OECs and TgSCs). Testing the synthetic compound on the phagocytosis of Beta (β) amyloid peptide, in OECs, astrocytes and microglia, showed an increase in peptide uptake in compound stimulated OECs as compared to non-stimulated ones. Astrocyte and microglia did not show any difference. In conclusion, this thesis gives us an understanding of the difference between CNS and PNS phagocytosis. While the different glial cells share many properties, OECs exhibit several characteristics which make them favourable candidates for transplantation therapies. Compound testing revealed that phagocytic activity can be stimulated and opens up avenues for identification of compounds that could be used to enhance therapeutic activity of glial cells in SCI and possibly in Alzheimer’s diseases research.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Pharmacy & Med Sci
Griffith Health
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16

Sandvig, Ioanna. "The role of olfactory ensheathing cells, MRI, and biomaterials in transplant-mediated CNS repair." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for sirkulasjon og bildediagnostikk, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-14639.

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Bruk av olfaktoriske ensheathing celler, MRI og biomaterialer i transplantasjonsmediert reparasjon av CNS skader Den beskrevne studien har brukt en interdisiplinær tilnærming for å evaluere transplantasjons mediert CNS reparasjon i en skademodell av synsnerven. Ved å integrere forskjellige MRI metoder har vi analysert olfaktoriske ensheathing celler’s (OEC) evne til å integrere og overleve in vivo i vår skademodell. Cellenes evne til å modulere regenerasjonen av den skadede synsnerven er også dokumentert ultrastrukturelt med elektronmikroskopi (EM). Studien har også omfattet in vitro analyser av interaksjonen mellom OEC og modifiserte biopolymerer i 2-og 3-dimensjonale matriser. Den spesifikke målsetningen med denne studien har vært: (a) Utvikle protokoller for effektiv merkning av OEC med mikron store jern partikler; (b) Kombinere cellulær MRI og mangan-forsterket MRI (MEMRI) for spatiotemporal monitorering av intravitreal (ivit) og intra-optisk nerve (iON) transplantasjon av OEC; (c) Studere celleimplantatenes evne til å promotere regenerasjon av synsbane aksoner etter skade i synsnerven både (i) longitudinelt in vivo med MRI og (ii) ultrastrukturelt med transmisjons elektron mikroskopi (TEM); (d) Produsere og teste modifiserte alginat strukturer som plattformer for kontrollert frigjøring av mangan (Mn2+) brukt som kontrastmiddel ved MEMRI; (e) Utvikle arginin-glycin-aspartat (RGD)-peptid alginater og karakterisere interaksjonen med OEC dyrket på disse modifiserte aliginat matrisene. I avhandlingen presenteres gjennomføringen av disse målene og belyser potensialet av å integrere MRI, biomateraler og celleterapeutiske teknologier i studier av transplantasjons-mediert reparasjon av skader i CNS.

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17

Wright, Alison Alexandra. "Olfactory Ensheathing Cell Behaviour and Interactions are Modulated by Secreted Products of OECs." Thesis, Griffith University, 2019. http://hdl.handle.net/10072/389563.

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The work presented in this thesis demonstrates that (1) the neurotrophins NGF and BDNF, which are secreted from OECs, significantly increase OEC proliferation, migration and phagocytosis; (2) OECs in vivo and in culture express the cytokine MIF (shown through immunolabelling, genetic expression and functional assays), and MIF stimulates OEC phagocytosis; (3) MIF is responsible for the segregation of OECs and macrophages in a model of the olfactory nerve as shown by their subsequent mingling upon MIF inhibition. The results here lend evidence that these proteins, which are secreted by OECs, may play a combinatorial role in the olfactory system’s regenerative potential and as such provide direction towards improving the therapeutic potential of OEC transplantation to treat SCI and other nervous system injuries.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Medical Science
Griffith Health
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18

Bianco, John I. "Stem Cells and Ensheathing Cells from the Nasal Olfactory Mucosa: a Tool for the Repair of the Damaged Spinal Cord." Thesis, Griffith University, 2008. http://hdl.handle.net/10072/368098.

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The olfactory mucosa has been shown to be a site where continual regeneration takes place throughout adulthood, making this system relatively unique with great potential in respect to autologous cell graft therapies. The olfactory mucosa is readily accessible with no deleterious effects on olfaction if biopsied. The presence of olfactory ensheathing cells (OECs), as well as a stem cell to facilitate the regeneration of this tissue, has been previously described. The first aim of this study was to further characterise olfactory ensheathing cells in rat and human and to gain some insights into their biology in vitro and in vivo, with the hope of applying this knowledge to clinical therapies employing autologous cell grafts. The second aim was to isolate stem cells in the form of neurospheres from the adult olfactory lamina propria, to elucidate their differentiation potential into both neural and non neural lineages, and to subsequently graft these cells into animal models of spinal cord injury to assess their behaviour in vivo in regards to survival, proliferation, and integration into the host spinal cord. Recovery of locomotor function due to axon regeneration across the lesion site following grafting was also assessed. Glial cells isolated from the adult olfactory lamina propria were identified as OECs in vitro and in vivo using the immunological markers GFAP, S100, and p75NTR. Neurotrophin growth factors were shown to promote their proliferation and purification in vitro from both rat and human. Immunocytochemistry and PCR were used to confirm the expression of neurotrophin trk receptors A, B, and C, as well as NT3, NGF and BDNF by OECs in rat and human. NT3 was shown to purify adult human OECs in vitro. Through the use of EGF and FGF2, it was shown that the olfactory lamina was capable of generating neurospheres consisting of a heterogeneous cell population, containing fully differentiated cells, progenitor cells, as well as undifferentiated stem cells indentified by the markers nestin and c-kit. Using growth factors, single or in combination, as well as tissue conditioned medium, olfactory stem cells within these neurospheres were induced to differentiate into the neural lineage, namely neurons, astrocytes, and oligodendrocytes. Non neural differentiation into liver, skeletal muscle, and cardiac cells was induced in vitro by cell-cell contact between neurospheres and frozen rat tissue sections.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Eskitis Institute for Cell and Molecular Therapies
Science, Environment, Engineering and Technology
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19

Westendorf, Kathryn A. "Brain lipid binding protein expression in lamina-propria olfactory ensheathing cells is regulated by delta/notch-like epidermal growth factor-related receptor." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/3196.

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The olfactory system exhibits remarkable regenerative ability in it’s neuronal population. The success of continuous neurogenesis is thought to be due, at least in part, to its unique glia – olfactory ensheathing cells (OECs). OECs bear characteristics of both peripheral and central glia, and serve to ensheath, guide and promote growth of olfactory receptor neurons (ORNs) throughout both development and adult life. Brain lipid binding protein (BLBP) is most highly expressed by radial glia during embryonic development. It is largely down-regulated in the adult CNS, but BLBP expression is retained in the adult by special subpopulations of glia, including OECs. BLBP expression is induced in radial glia via Notch signaling, but it is not known if these same mechanisms regulate BLBP expression in the adult CNS. Axonal-glial signaling is a dynamic process whereby closely apposed neuronal and glial cells regulate the growth, maintenance and plasticity of one another through direct cell-cell signaling. Delta/Notch-like EGF-related receptor (DNER) is a transmembrane protein expressed by Purkinje cells which has been implicated in the regulation of BLBP in Bergmann glia during cerebellum development through Notch1 deltex-dependent non-canonical signaling. We have found that DNER is expressed in more mature ORNs, and other exclusive subpopulations of cells within the CNS. OECs in close apposition with DNER-expressing ORNs in vivo appear to maintain the highest BLBP expression found in the nervous system through development and adulthood. Immunofluorescence shows that this close relationship between BLBP expressing cells and DNER expressing cells also appears to be retained in specialized areas such as the hippocampus, retina and spinal cord, throughout mouse CNS development as well as in the mature system. Removing DNER or axonal input in vivo decreases the robustness of OEC BLBP expression, and the number of cells in OEC culture expressing BLBP decreases rapidly with time. OEC co-culture with a DNER expressing monolayer increases the number of OECs in vitro which express BLBP, providing evidence for the regulation of BLBP expression in OECs by DNER expression in apposing ORNs.

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20

Vukovic, Jana. "An in vitro and in vitro study on the role of the glycoprotein fibulin-3 in olfactory nerve growth and repair." University of Western Australia. School of Anatomy and Human Biology, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0182.

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The primary olfactory pathway in adult mammals has retained a remarkable potential for self-repair. Olfactory ensheathing cells (OECs), specialized glial cells within the olfactory nerve, are thought to play an important role in the ongoing growth and replenishment of sensory connections in this system. To gain insight into novel molecules that could mediate OEC-supported growth of axons within the olfactory nerve, gene expression profiling experiments revealed very high expression of the fibulin-3 glycoprotein in OECs. To date, research on fibulin-3 has been limited and mainly focused on its involvement in Doyne honeycomb retinal dystrophy, vasculogenesis and tumor formation. As the extracellular matrix associated with OECs is thought to be an important contributor to a growth-permissive environment, the main aim of this thesis was to define a putative role for fibulin-3 during olfactory receptor neuron replacement and regeneration. This hypothesis was investigated in a series of in vitro and in vivo experiments that involved lentiviral vectors to manipulate fibulin-3 gene expression in OECs as well as the use of knock-out mice. Using genetically-modified OECs, experimental data showed that increased levels of fibulin-3 induced morphological changes in OECs and also impeded their migration. Lentiviral vector-mediated expression of fibulin-3 in OECs also had an inhibitory effect on neurite outgrowth from dorsal root ganglion explants. On the other hand, knock-down of fibulin-3 levels via siRNA technology resulted in reduced proliferation. Comparative lesioning experiments in fibulin-3 knock-out and wild-type mice allowed for further assessment of a role for fibulin-3 in olfactory nerve repair in vivo. Two experimental injury models, i.e. epithelial (Triton-X) lesioning and olfactory bulbectomy, were employed. The results obtained were in line with in vitro observations. A lack of fibulin-3 in knock-out mice resulted in a seemingly augmented regeneration of the olfactory epithelium at 10 days post-injury. However, at the latest recovery time point of 42 days post-injury, an impaired recovery of the olfactory epithelium from the experimental insults was observed. Although the precise mechanism for the latter phenomenon is not yet fully understood, our data point towards several factors which include vascular abnormalities and altered cell proliferation within the olfactory epithelium. Additionally, the precise protein distribution of another wide-spread family of extracellular matrix molecules, the laminins, was investigated in this thesis. It was of interest to investigate the spatiotemporal expression of laminin isoforms during iii olfactory nerve development and regeneration as these molecules may have distinct roles in promoting olfactory sensory neuron growth and patterning. In situ hybridization and immunohistochemical studies concluded that laminin-211 and laminin-411 were the most likely candidates to play such a role. In summary, this thesis provides new insights into the role of the extracellular matrix, fibulin-3 in particular, in regulating cell migration, division and axonal growth in the primary olfactory pathway. Such knowledge also gives a greater understanding of the molecular mechanisms by which OEC transplants may enhance axonal regeneration elsewhere in the CNS.

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21

Techangamsuwan, Somporn. "Immortalization and proliferation of adult canine Schwann cells and olfactory ensheathing cells and their infection with canine distemper virus." Gießen : DVG-Service, 2009. http://d-nb.info/997318902/34.

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22

Ibrahim, A. "The use of olfactory ensheathing cells to promote regeneration of axons of central nervous system neurons." Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1370619/.

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The mammalian central nervous system (CNS), including that of humans, has a poor capacity to repair and regenerate after injury. The outcome of brain and spinal cord injuries is a devastating loss of function and profound disability to the patient and tremendous socio‐economic burden to society. In this thesis, I first developed a behavioural model of brachial plexus dorsal root avulsion injury quantifying the subsequent behavioural deficit. Secondly, I transplanted olfactory bulb ensheathing cells in the dorsal root lesions and carried out functional, anatomical, electrophysiological assessments. The data showed that while dorsal roots avulsion injury of C6 to T1 created a permanent climbing deficit, the lesioning of 3 or fewer roots produced a less severe form of the deficit and rats were still able to climb by masking the effects of the lesion with time. After transplanting OECs into the dorsal root lesions, 70% of rats had restoration of paw grasping function, starting from 2‐3 weeks post surgery while none of rats without OEC transplant recovered climbing function. The transplanted cells induced a mass of reactive tissue which served as a bridge for regenerating axons to cross over into the spinal cord. Individual axonal fibres were detected (labelled with anterograde axonal tracer) crossing the dorsal root entry zone, entering the spinal cord, arborising within the laminae of the spinal cord grey matter. 6‐8 weeks after receiving OEC transplants, 7 out of 8 rats had cord dorsum field potentials detected at the cord after stimulating the median nerve. In the control group of 4 rats with chronic lesions but without OECs transplant, none showed cord dorsum potential nor cuneate responses up to 8 weeks after surgical intervention. I concluded that OEC transplants promote recovery of paw grasping functions and electrophysiological transmission in a dorsal root injury model.

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23

Keyvan-Fouladi, Naghmeh. "Functional repair of the corticospinal tract by delayed transplantation of olfactory ensheathing cells in adult rats." Thesis, Open University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.402238.

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24

De, Mello Thalles R. B. "Olfactory ensheathing glia : an investigation of factors affecting responsiveness of these cells in vitro and in vivo." University of Western Australia. School of Anatomy and Human Biology, 2006. http://theses.library.uwa.edu.au/adt-WU2006.0044.

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[Truncated abstract] Olfactory ensheathing glia (OEG) have been demonstrated to improve functional and anatomical outcomes after injury to the nervous system and are currently being trialled clinically. This thesis presents the investigation of two important issues in OEG biology. The first study (Chapter 2) investigates effects of different members of the neuregulin (NRG) family of molecules on the proliferation of OEG, as a means of quickly obtaining large numbers of cells for clinical or experimental use. We report that NRG-1β, but not NRG- 2α or NRG-3, has a significant proliferative effect. Furthermore, we report for the first time that use of different mitogens (forskolin and pituitary extract) commonly used to expand these cells in vitro, can have a significant effect on the responsiveness of OEG to added NRG in subsequent mitogenic assays. OEG grown initially with forskolin and pituitary extract exhibited increased basal proliferation rates in comparison to OEG originally expanded without these factors, and this increased rate of proliferation was sustained for at least 6 days following their withdrawal from the culture medium. We also report for the first time the expression pattern of ErbB2, ErbB3 and ErbB4 receptors on p75-selected OEG, and investigate their contribution to the NRG mitogenic effect by the use of inhibitory ErbB antibodies. Our second study (Chapter 3) seeks to clarify the role of OEG in promoting myelination of central nervous system neurons. In this study we have investigated the myelinating ability of OEG derived from embryonic (EEG), postnatal (PEG) and adult tissue (AEG) both in vitro and in vivo. OEG selected by p75-immunopanning were co-cultured with dissociated cultures of TrkA-dependant embryonic dorsal root ganglion (DRG) neurons. EEG, but not AEG or PEG, successfully myelinated DRG neurons in the presence of serum and/or ascorbate. AEG also failed to myelinate GDNF-dependant embryonic DRG cultures, and growth factor-independent adult DRG cultures. Transplantation of OEG into lysolecithin demyelinated spinal cord demonstrated distinct ultrastructural differences between transplants of OEG derived from animals of different ages. Furthermore, we demonstrate that clearance of degraded myelin from the lesion site appears to be more effective when animals are transplanted with EEG rather than AEG or Schwann cell preparations. These results suggest that myelinating potential of OEG in vitro and behaviour of these cells following transplantation in vivo are developmentally regulated.

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25

Granger, Nicolas. "Effects of intraspinal transplantation of mucosal olfactory ensheathing cells in chronic spinal cord injury in domestic dogs." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608161.

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26

Amaya, Daniel Alejandro. "Integration of the Peripheral and Central Nervous System During Development of the Murine Olfactory Nerve." Thesis, Griffith University, 2016. http://hdl.handle.net/10072/367158.

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The need to develop therapies for neurodegenerative diseases and spinal cord injuries has led researchers to study the primary olfactory system, as it continuously renews itself throughout life, and completely regenerates after injury. A pool of cells that line the basal surface of the olfactory epithelium gives rise to new olfactory neurons both during normal olfactory nervous system turnover and to a greater extent following injury. The unique, growth promoting olfactory system environment is crucial for this neurogenesis and regeneration. Significantly glial scarring (as is typically seen in neurodegeneration and neural damage elsewhere in the nervous system) is largely absent following injury to the olfactory tract. Thus replicating the favourable condition in the olfactory nervous system would be invaluable for developing these successful therapies. If we can mimic the cellular and molecular mechanisms responsible for maintenance andregeneration of the olfactory neurons, we can promote regeneration and facilitate the reestablishment of connectivity in damaged neural tracts. To model neural regeneratio n strategies in the olfactory nervous system we need to understand the normal olfactory system biology.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Natural Sciences
Science, Environment, Engineering and Technology
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27

Reshamwala, Ronak S. "Novel Surgical Approaches for Transplanting Three-Dimensional Constructs of Olfactory Ensheathing Cells to Repair the Injured Spinal Cord." Thesis, Griffith University, 2020. http://hdl.handle.net/10072/395103.

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Neurological injuries are very difficult for the human body to heal, as neurons are highly specialized cells which do not undergo cell division in adulthood. Central nervous system (CNS) neurons exhibit particularly low capacity for regeneration, due to both intrinsic cellular and environmental factors. For this reason, spinal cord injuries are usually irreversible in nature and they usually result in at least some motor paralysis and/or loss of sensory function. Higher level (cervical) injuries typically lead to widespread paralysis and sometimes death. Spinal cord injuries are a serious health problem and a very large burden on health care system. Therefore, therapies that repair the injured spinal cord will bring considerable benefits to patients as well as large socioeconomic benefits to the society. One particular region of the nervous system that naturally constantly undergoes regeneration is the primary olfactory nervous system, which is comprised of the olfactory nerve and the outer layer of the olfactory bulb (the nerve fibre layer). Olfactory neurons continuously degenerate, and new neurons originate from progenitor cells in the olfactory neuroepithelium of the nasal cavity. The glial cells of this system, olfactory ensheathing cells (OECs), are thought crucial for this process and are considered to have unique growth-promoting properties. For these reasons, transplantation of OECs into damaged nervous system regions is emerging as a promising therapy. OECs can be cultured from biopsies from either the olfactory mucosa (which contains olfactory nerve fascicles) or from the olfactory bulb. To date, numerous studies of OEC transplantation into rodent models of spinal cord injury as well as human clinical trials have been conducted. OEC transplantation has proven to be safe and feasible for spinal cord injury repair in humans, but outcomes in both animal studies and human clinical trials are highly variable and the method needs considerable improvement and standardization. One of the major limiting factors for the efficacy of this therapy is cell survival and integration following transplantation. One interesting avenue for improving both cell survival and integration is to transplant the cells as a three-dimensional construct rather than as cells suspended in liquid. The mechanisms by which OECs can induce and sustain neural regeneration are becoming well characterised in the literature, however, little in vivo evidence exists regarding the interrelationship between (1) cell survival and structural repair, (2) structural repair and functional improvement and (3) different injury conditions and cell survival/integration. Moreover, over two thirds of studies to date have used OECs derived from the olfactory bulb (OB-OECs) rather than mucosa-derived OECs (OMOECs). From a clinical viewpoint, OM-OECs are highly favourable since bulbar biopsies induce damage to the CNS and require intracranial brain surgery, whilst OMOECs can be isolated from a peripheral biopsy of the olfactory mucosa at the roof of the nasal cavity. Thus, more studies need to focus on transplantation of OM-OECs rather than OB-OECs. The primary focus of this thesis was to improve the therapeutic potential of OMOEC transplantation for spinal cord injury repair, with particular focus on enhancing cell survival and integration, by improving the surgical transplantation approach. A key component of this strategy was to transplant the cells in a 3D conformation (spheroids). This work also evaluated the effects of different injury conditions on the structural repair and functional regain following treatments. The aims of this Thesis included (1) the establishment of a robust murine spinal cord transection-type injury model and, later, adaptation to contusion-type injury, (2) testing of different methods for delivering OECs to the spinal cord injury site (different configurations of cell suspension, cell spheroids), (3) determination of how the chronicity of injury (time between injury and OEC transplantation) affects cell survival and integration, (4) assessment of how cell transplantation affects structural repair and (5) determination of the link between structural repair and functional outcomes. Throughout these aims, the aspect of OEC purity was focused on. OEC cultures from the olfactory mucosa not only contain OECs but also other cell types, in particular olfactory nerve fibroblasts, which can affect both the transplanted cells and cells endogenous to the injury site. Therefore, OECs were transplanted at different purities and resultant structural/functional outcomes were assessed. A minor aspect of this Thesis also focused on optimisation of a treatment delivery matrix. A set of in vitro experiments were conducted to determine the best composition of the matrix which could not only augment and contain the OECs in a 3D form while transplanting, but also enable them to migrate and form bridges across the injury site. This project was designed to ultimately provide insight for the clinical translation of this therapy with focus on improving cell survival and integration at the injury site, leading to enhanced structural repair and functional regain, paving the way for clinical trials in the coming future. As a result of this undertaking, the following key outcomes have been achieved: Development of a murine transection-type spinal cord injury model: A novel approach for laminectomy at the T10 spinal level was developed that can be used to induce a complete transection-type injury (using a narrow blade). The advantage of this method is that it is precise, it minimises the collateral tissue damage and mitigates blood loss. The complete transection type injury results in complete loss of sensory-motor and autonomic function below the level of injury, which is why a manual bladder expression protocol was also established during the course of the post-surgical care. A subjective assessment system was also developed to study the sensory recovery and bladder function recovery along with standardised motor behavioural tests. Transplantation matrix can support OECs in vitro: The in vitro experiments show that the transplantation matrix can provide stable and long term support to the 3D cultured cells and allow them to freely migrate and interact with each other. The matrix provides a physiological scaffolding to the OECs that can hold the 3D constructs in place without hindering the movements of individual cells. Transplantation of OECs in 3D improves cell survival, integration and structural repair: To determine whether transplantation of cells in 3D rather than in suspension would improve spinal cord injury repair, a comparison was conducted between suspension injection (the literature gold-standard) and a number of different configurations of cell spheroid transplantations. The best results showed ~15-20% cell survival one week following the transplantation, which is a significant improvement upon that reported for cell suspension in the literature (~0.6% cell survival was reported in the previous study that most resembles the experimental design used in this Thesis). Spheroid transplantations also demonstrated relatively better cell morphology in vivo compared to the published reports and better structural repairs post transplantation compared to the untreated controls. Interestingly, contrary to the evidence presented throughout the literature, the chronicity of the injury appeared not to have any significant effects on the cell survival when cells were transplanted in spheroids. Transplantation of OECs spheroids leads to functional regain: The treatments with the best functional outcomes were the ones when OECs were delivered to the SCI site in the form of two medium-sized spheroids, as compared a single large spheroid or four smaller-sized spheroids. The best cell survival results were also observed with the same modality. Although all spheroid treatments resulted in functional recovery, best recovery was observed with large and midsized spheroids. This functional status of the animals was assessed by the conventionally used motor function measurements such as open field behavioural scores – Basso Mouse Scale and Toyama Mouse Scale, and once the animals showed consistent stepping – DigiGait (an automated gait analysis of ventral plane images of the mouse’s gait). As mentioned earlier, additional subjective assessments of reflex recovery, sensory functions and autonomic status (bladder function) were also employed for the same. Different cell purities show different recovery trends: Behavioural studies showed that significant differences in the functional recovery trends depending on the purity of transplanted cells. Unpurified transplants showed faster onset of recovery, however, the recovery plateaued soon after that. On the contrary, the purified transplants showed a slower onset of recovery, which continued throughout the follow up period. Unfortunately, due to the low purity of OECs in the unpurified transplants, a comparison between cell survival and integration could not be done. This was due to the fact that the treatment cells were sourced from a mouse line genetically modified to express DsRed reported protein driven by s100-β promoter. This means that the OECs (and some other cells such as Schwann cells) fluoresce red under the ultraviolet light, which makes it difficult to visualize the non-DsRed cells (or cells other than the OECs). Evidence of structural repair, which links to functional outcomes, and evidence of cell integration: Histological analysis of the treated spinal cords revealed structural repair in terms of injury gap size reduction, axonal sprouting and formation of cellular bridges across the injury site. High-magnification imaging revealed evidence of OEC integration with both astrocytes and the sprouting axons. The transplanted cells were observed to ensheathe the axons extending across the injury site. Overall, the animals for which considerable structural repair was observed also were the ones that showed functional improvement. Development of a contusion-type spinal cord injury model: In the final stages of this Thesis, the treatment was also optimised for the use in an incomplete – contusion type injury which is clinically more relevant. Here, a contusion-type injury using the Infinite Horizons Impactor was induced at T10 level (the same laminectomy approach as for transection-type injury was used). A longterm follow-up of the two main injury models – transection and contusion, was also conducted to establish and compare the two models. It was discovered that the incomplete contusion injury resulted in a degree of spontaneous functional recovery for a short period following the injury, while the complete transection type injury resulted in total and irreversible loss of function. Potential links of animal behaviour and physical condition to the different stages of injury were also observed.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environment and Sc
Science, Environment, Engineering and Technology
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Tello, Velasquez Johana Paola. "Identification of Natural Compounds that Regulate Glial Cell Proliferation and Migration for Spinal Cord Injury Transplantation Purposes." Thesis, Griffith University, 2016. http://hdl.handle.net/10072/366849.

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Transplantation of glial cells, particularly olfactory ensheathing cells (OECs) and Schwann cells (SCs) is one of the most promising strategies for the treatment of spinal cord injury and for other neural repair therapies. Effective proliferation and migration of glial cells are essential to optimize clinical applications; therefore identification of molecules that can promote and regulate these biological features is of great interest. The use of neurotrophic factors has long been considered as a potential approach, but, because of their high molecular weight; most are unstable. An important number of natural products have been reported in the literature to be able to mimic the effect of these neurogenic factors, mostly Curcuminoides (derived from the root turmeric) and Linckosides (isolated from the starfish Linckia laevigata). These products have been demonstrated to be neuroprotective and neurogenic on nerve cells, however it is not comprehensively known if these neurogenic natural compounds can influence the biological activity of glial cells. This thesis presents the evaluation of the effects of four known natural neurogenic compounds on the behaviour of OECs and SCs using proliferation assays and time-lapse microscopy analysis methods.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Natural Sciences
Science, Environment, Engineering and Technology
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[Verfasser], Somporn Techangamsuwan. "Immortalization and proliferation of adult canine Schwann cells and olfactory ensheathing cells and their infection with canine distemper virus / by Somporn Techangamsuwan." Gießen : DVG-Service, 2009. http://d-nb.info/997318902/34.

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Sarwat, Mariah. "Peptide functionalised hydrogels for tissue regeneration." Thesis, Queensland University of Technology, 2019. https://eprints.qut.edu.au/157715/1/Mariah_Sarwat_Thesis.pdf.

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This project aimed to develop a therapeutic intervention to decrease scarring and encourage regeneration following spinal cord injury. For this purpose, in vitro 3D microenvironment comprising Olfactory ensheathing cells (OECs) encapsulated in peptide functionalised hydrogels were synthesized using a robot. To optimise the hydrogel system a library of peptides was screened from which different hydrogel formulations were identified to support cell adhesion, proliferation and migration. With this approach an ideal 3D hydrogel system for future in vivo testing will be developed and ultimately clinical translation. In addition, a 3D in vitro model simulating a nerve guidance channel and a biosensor for detecting oxidative stress was also studied to understand the behaviour of OECs in in vitro cell culture systems.

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Walkden, Heidi. "Bacterial infection of the brain: how bacteria penetrate the CNS by invading peripheral nerves." Thesis, Griffith University, 2020. http://hdl.handle.net/10072/395110.

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Bacterial infections of the central nervous system (CNS), though uncommon, are associated with very high rates of morbidity and mortality. Recent research has also highlighted the correlation between pathogens and chronic diseases of the CNS, such as neurodegenerative disorders, particularly Alzheimer’s disease. Whilst some bacteria can cross the blood-brain/blood-cerebrospinal fluid barriers, to date, other pathways by which bacteria enter the CNS remain largely unknown. Identifying alternative paths by which pathogens can enter the CNS is thus important for developing novel strategies preventing CNS infection and potential long-term sequelae. Novel evidence suggests some bacterial species (as well as certain viruses and amoebae) can enter the brain via the cranial nerves innervating the nasal cavity, particularly the olfactory nerve that mediates the sense of smell and connects the nasal cavity with the olfactory bulb in the forebrain. The trigeminal nerve also innervates the nasal cavity and constitutes another invasion path. Only a handful of pathogens are thought to use cranial nerves to reach the brain; certain Chlamydia species (spp.) being amongst these. Chlamydia pneumoniae is to date the bacterium with the strongest established link to Alzheimer’s disease. Previous research by our laboratory has also demonstrated that the bacterium causing the tropical disease melioidosis, Burkholderia pseudomallei, can invade both the olfactory and trigeminal nerves, travel along these nerves, to then infect the CNS (the olfactory bulb and brainstem, respectively). We have also previously shown that in outbred mice, the olfactory nerve is resistant to B. pseudomallei infection. The nasal mucosa contains both innate and adaptive immune components and prevents many infections. If pathogens penetrate the mucosal barrier and reach nerves, glial cells of the nerves can also combat the infection. Whilst only a few macrophages are present inside the olfactory nerve fascicles, olfactory nerve glial cells, termed olfactory ensheathing cells (OECs), are powerful phagocytes with innate immune functions. Thus, in addition to the immune cells and other components of the immune system in the nasal mucosa, cranial nerve glia are thus thought to be key for preventing CNS infection, explaining why such infections are relatively rare. Some pathogens, however, can evade destruction by these cells and invade the nerves, however, it remains largely unknown which pathogens are capable of doing so. Furthermore, injuries to the nasal epithelium are common, and if the mucosal barrier is removed by injury, perhaps it is easier for pathogens to infect the underlying nerves (in particular the olfactory nerve) and then reach the CNS. With the exception of one bacterium (Staphylococcus aureus) for which injury has been shown to allow infection of the olfactory nerve, it also remains unknown whether epithelial injury increases the risk of pathogens invading the CNS via these paths. Thus, we need to determine which pathogens are capable of invading the CNS via nerves connecting the nasal cavity and the brain, and whether epithelial injury increases the risk of infection. Furthermore, determining the cellular mechanisms that protect against microbial invasion of the CNS via nerves, as well as why certain pathogens can evade destruction of the immune system may pave the way for the development of novel therapies preventing and treating CNS infections. The key aims of this thesis were to determine (1) whether prior injury to the nasal epithelium could allow B. pseudomallei to invade the olfactory nerve and bulb in the mouse strain where this nerve is usually resistant to this infection, (2) whether the bacterium Chlamydia muridarum (which infects mice and is commonly used to study Chlamydia spp. infection in rodents) can utilise cranial nerves that innervate the nasal cavity to invade the CNS and, if C. muridarum can invade the CNS, to then determine whether the bacteria remained viable and (3) whether C. muridarum can infect OECs, and how OECs respond to C. muridarum in vitro. This thesis demonstrated that injury to the olfactory epithelium allowed the invasion of the olfactory nerve and bulb by B. pseudomallei in S100β-DsRed Quackenbush mice, in which the olfactory nerve is otherwise typically resistant to infection. This work also showed that C. muridarum can rapidly (within 48 h) reach the CNS (olfactory bulb and cerebral cortex) via the olfactory nerve, as well as infect the trigeminal nerve, in mice. Immunohistochemistry showed the presence of C. muridarum inclusion bodies (membrane-bound components inside which the bacteria replicate intracellularly) and viable C. muridarum bacteria were also isolated from these regions. C. muridarum was shown to readily infect OECs in vitro, which led to the upregulation of a range of cytokines. The outcomes from this project will contribute to an increased understanding of how bacteria can reach the CNS and has revealed that injury to the nasal epithelium may increase the risk of CNS bacterial invasion via the olfactory nerve. The outcomes also include an increased understanding of how olfactory nerve glia become infected by and respond to bacteria. This work may also contribute towards the growing body of knowledge regarding the link between pathogens and certain diseases of the CNS, such as Alzheimer’s disease. Furthermore, with an increased understanding of how glial cells respond to bacteria, new therapies may be developed that stimulate bacterial degradation by the glia. Such therapies may provide valid future alternatives to antibiotics, also combating the growing problem of antibiotic resistance. Thus, this work may contribute to the foundation required to develop therapies to treat diseases that are currently not curable, as well as to better diagnose and identify susceptibilities to certain conditions.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Medical Science
Griffith Health
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Kalincik, Tomas Medical Sciences Faculty of Medicine UNSW. "Disturbances of autonomic functions in spinal cord injury: autonomic dysreflexia and thermoregulation." Publisher:University of New South Wales. Medical Sciences, 2009. http://handle.unsw.edu.au/1959.4/43516.

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Disorders of the autonomic nervous system constitute serious complications of spinal cord injury (SCI) and their treatment is usually highly prioritised by spinal patients. Among these, autonomic dysreflexia and impaired thermoregulation are potentially life threatening conditions and require effective management. Olfactory ensheathing cells (OECs), progenitor cells and polymeric scaffolds have been tested in animal models of SCI and some of them have been considered for clinical trials. However, evaluation of the effect of such interventions on autonomic functions has received only rudimentary attention and would require a more thorough experimental assessment before the methods are utilised in human patients. This thesis tested two potential therapeutic strategies for autonomic dysreflexia and examined disorders of thermoregulatory functions in a rat model of spinal cord transection. Magnitude and duration of autonomic dysreflexia were evaluated with radio telemetry in spinalised animals treated with (i) implants of OECs and olfactory neurosphere-derived cells seeded in poly(lactic co glycolic) porous scaffolds or with (ii) transplants of OECs alone. (iii) Effects of SCI and of OECs on the morphology of sympathetic preganglionic neurons (SPNs; which are involved in pathogenesis of autonomic dysreflexia) stained for NADPH diaphorase were examined. (iv) Doppler ultrasonography and infrared thermography were used to assess responses of tail blood flow and surface temperature to cold. Transplants of OECs alone, but not in combination with olfactory neurosphere-derived cells and polymeric scaffolds, resulted in significantly shortened episodes of autonomic dysreflexia. This may be attributed to the alterations to the morphology of SPNs adjacent to the lesion: a transient increase in the morphometric features of the SPNs was evoked by spinal cord transection and this was further altered by transplantation of OECs. The thesis also showed that local responses of tail blood flow and temperature to cold were not abolished by complete SCI suggesting that temperature homeostasis could still be maintained in response to cold. It is hypothesised that OECs facilitate improved recovery from autonomic dysreflexia through alteration of the morphology of SPNs. Furthermore, it is suggested that the role of the tail in heat conservation can be regulated by mechanisms that are independent of the descendent neural control from supraspinal centres.

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Chen, Mo. "Natural products and glial cell therapy for repairing the nervous system." Thesis, Griffith University, 2019. http://hdl.handle.net/10072/389731.

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The problem: In Australia, over 12,000 people live with a spinal cord injury (SCI) and at least one new case occurs every day. Currently, there is no effective treatment for SCI. Transplantation of olfactory ensheathing cells (OECs; the glial cells of the primary olfactory nervous system) is a promising therapy, in particular autologous transplantation. OECs exhibit unique properties which stimulate neuronal growth and axonal extension, including structural and neurotrophic/guidance support. OECs also function as immune cells and remove (phagocytose) cell debris from the injury site. Furthermore, OECs migrate across the injury site and provide support for regenerating axons. However, functional outcomes in both animal studies and human clinical trials vary greatly, and there are key obstacles in this therapy. These include insufficient cell proliferation rate (both prior to transplantation and after transplantation), cell migration rate and phagocytic activity. If these cell behaviours could be stimulated, the therapeutic potential of OECs would be significantly enhanced. Another important avenue for improvement is the development of novel three-dimensional (3D) cell constructs suitable for both pre-transplantation work (cell culture and drug screening) and for transplantation of OECs directly as a 3D structure into the nervous system injury site. In summary, this work has (1) identified three natural compounds with potential to promote favourable OEC behaviours relevant for neural repair, and (2) led to the development of a novel 3D culture system in which cells rapidly self-assemble without any added ingredients, applicable to a wide range of neural repair avenues. Thus far, the outcomes of this thesis have led to two patent applications, two first-author publications, three first-author manuscripts in submission/preparation, and 1 patent application in preparation, as well as contributing to four papers/manuscripts led by other researchers in the Clem Jones Centre for Neurobiology and Stem Cell Research. The future directions towards enhancing the outcomes of OEC transplantation will be based on the combination of the identified natural products and the developed NLM/NLMNB 3D cell culture methods.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environment and Sc
Science, Environment, Engineering and Technology
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Mayeur, Anne. "Role de la protéine ADAMTS 4 sur la repousse nerveuse centrale induite par les cellules gliales olfactives in vivo chez la souris. Potential of olfactory ensheathing cells from different sources for spinal cord repair Inhibition of ADAMTS-4 Expression in Olfactory Ensheathing Cells Enhances Recovery after Transplantation within Spinal Cord Injury." Thesis, Normandie, 2020. http://www.theses.fr/2020NORMR003.

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Une lésion de la moelle épinière induit une perte sensorimotrice permanente en sous-lésionnel. A ce jour, une grande variété de cellules a été utilisée comme biothérapie pour soigner les lésions médullaires dans différents modèles animaux. Les cellules gliales olfactives (CGO) sont l’une des plus prometteuses. En effet, il a été démontré que les CGO améliorent la récupération dans de nombreuses études sur les animaux, ainsi que sur des patients (essais de Phase I/Iia). Cependant, il a été rapporté que le niveau de récupération varie significativement selon les patients. Par conséquent, il est primordial d’améliorer l’efficacité des CGO. Récemment, il a été démontré que l’inhibition de l’expression d’ADAMTS 4 (une métalloprotéase connue pour lier et dégrader les chondrointin sulfate proteoglycans) dans les cellules gliales in vitro augmente leur synthèse de facteurs neurotrophiques. Dans notre équipe, nous avons déjà démontré que les CGO produisent ADAMTS 4 in vitro. Nous avons émis l’hypothèse que l’expression des facteurs neurotrophiques sécrétés par les CGO peut être augmentée par la suppression d’ADAMTS 4. Nous avons étudié leur potentiel de régénération après une lésion médullaire sur un modèle murin. Nos résultats montrent que les cultures primaires de CGO bulbaires ADAMTS 4 KO régulent à la hausse leur expression de facteurs trophiques in vitro, et que la transplantation de ces mêmes cellules dans un modèle de lésion spinale sévère augmente la récupération fonctionnelle et la réparation tissulaire in vivo. Au total, notre étude révèle, pour la première fois, que la greffe de cultures primaires de CGO bulbaires peut être potentialisée par une inhibition de l’expression d’ADAMTS 4
A spinal cord injury (SCI) induces a permanent sensorimotor impairment below the injury level. To date, a wide variety of cells have been used as biotherapy to treat spinal cord injuries in different animal models. Olfactory ensheathing cells (OECs) are one of the most promising. Indeed, OECs have been shown to improve recovery in many animal studies, as well as in patients (Phase I/IIa trials). However, it has been reported that the level of recovery significantly varies among patients. Therefore, it is essential to improve the regenerative efficiency of OECs. Recently, inhibition of the expression of ADAMTS 4 (a metalloprotease known to bind and degrade chondroitin sulfate proteoglycans) in glial cells in vitro has been shown to increase their synthesis of neurotrophic factors. In our team, we have already demonstrated that OECs produce ADAMTS 4 in vitro. We hypthesized that the expression of neurotrophic factors secreted by OECs can be increased by the suppression of ADAMTS 4. We studied their regenerative potential after spinal cord injury in mice. Our results show that ADAMTS 4/KO bulb primary OECs cultures upregulate their trophic factors’ expression in vitro, and that transplanting these same cells into a severe SCI increases functional recovery and tissue repair in vivo

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Münchhoff, Maximilian [Verfasser], Bernhard [Akademischer Betreuer] Meyer, and Thomas Rudolf [Akademischer Betreuer] Tölle. "Evaluating the viability of Olfactory Ensheathing Cells transduced to overexpress Glial Cell Line Derived Neurotrophic Factor in a rat model of Dorsal Root Injury / Maximilian Münchhoff. Gutachter: Thomas Rudolf Tölle. Betreuer: Bernhard Meyer." München : Universitätsbibliothek der TU München, 2012. http://d-nb.info/1022885677/34.

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Geller, Sarah. "Caractérisation des cellules gliales olfactives associées aux neurones à GnRH-I : rôle dans le développement de ces neurones." Thesis, Tours, 2013. http://www.theses.fr/2013TOUR4011/document.

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Chez le mammifère la fonction de reproduction est sous le contrôle des neurones hypothalamiques à GnRH-I. Au cours du développement embryonnaire ces neurones migrent de la fosse nasale vers le cerveau. De nombreuses études s’intéressent aux facteurs impliqués dans leur migration, mais l’influence de leur environnement cellulaire est très peu étudiée. Nous avons émis l’hypothèse que les neurones à GnRH-I d’origine extra-cérébrale possèdent un environnement gliale nécessaire à leur migration, connaissant le rôle de ces cellules dans l’ontogenèse neuronale du cerveau. Nos résultats montrent que 1) les neurones à GnRH-I sont associés à des cellules gliales au cours de leurs migrations nasale et télencéphalique 2) ces cellules gliales sont des progéniteurs des cellules gliales olfactives engainantes qui se différencient dans les régions rostrales au cours de la migration neuronale. 3) ces cellules expriment des gènes codant pour des facteurs impliqués dans la migration de ces neurones. 4) le transcriptome de ces cellules gliales est perturbé en présence d’un perturbateur endocrinien œstrogèno-mimétique, et touche des familles de gènes impliquées dans les molécules d’adhésions cellulaires nécessaire à la migration et à la régulation de l’activité des neurones à GnRH-I
GnRH-I cells control reproduction functions in mammals. These cells are extra cerebral since they come from the nasal pit and migrate to the forebrain during embryonic development. Numerous studies have described the influence of different molecules on the migration of GnRH-1 neurons, however, the role of microenvironment cells remains poorly understood. Considering the role of glial cells in the forebrain’s neuronal migration, we had hypothesized that extra-cerebral GnRH-I neurons possess a glial environment necessary for their migration from the nose to the brain. Our results demonstrated that 1) GnRH-I neurons are associated with glial cells during their migration in the nasal septum and forebrain 2) These glial cells are progenitors of olfactory ensheathing cells, and differentiated within the rostral regions during neuronal migration. 3) These cells express genes encoding factors involved in GnRH-I neurons migration 4) Glial cells transcriptome are disrupted with estrogen-mimicking endocrine disruptor, and affects gene families involved in cell adhesion molecules necessary for migration and activity regulation of GnRH-I neurons

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Chalfouh, Chaima. "Effet de la stimulation magnétique répétitive trans-spinale comme thérapie non invasive dans le cadre des lésions médullaires. The Regenerative Effect of Trans-spinal Magnetic Stimulation After Spinal Cord Injury: Mechanisms and Pathways Underlying the Effect FoxJ1 regulates spinal cord development and is required for the maintenance of spinal cord stem cell potential Inhibition of ADAMTS-4 Expression in Olfactory Ensheathing Cells Enhances Recovery after Transplantation within Spinal Cord Injury Resident neural stem cells guarantee the regeneration promoted by bulbar olfactory ensheathing cell transplantation after spinal cord injury." Thesis, Normandie, 2020. http://www.theses.fr/2020NORMR099.

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Les lésions de la moelle spinale constituent un problème de santé public d’une ampleur grandissante. Bien que l’espérance de vie ait été améliorée, les patients médullo-lésés souffrent de certains handicaps entraînant une perte partielle ou complète des fonctions sensorielles et/ou motrices. La moelle spinale lésée entreprend aussitôt une réponse à cette lésion. Chronologiquement, la lésion se divise en deux grandes phases : la phase primaire qui se caractérise par la destruction tissulaire induite par le traumatisme mécanique, suivie d’une destruction cellulaire. Alors que la phase secondaire est la conséquence moléculaire et cellulaire de la phase primaire. Durant plusieurs années, différentes stratégies thérapeutiques ont été proposé principalement la thérapie cellulaire qui a prouvé ses effets bénéﬁques dans différents modèles expérimentaux de la lésion , mais de nombreux obstacles sont à prendre en considération tel que, principalement, son caractère invasif. aﬁn de pouvoir l’appliquer chez l’homme d’une manière efficace et reproductible . A la vue de ces contraintes cliniques, nous avons décidé d’explorer un traitement non invasif connu pour ses effets neuroprotecteurs et neurotrophiques dans le SNC ; la stimulation magnétique répétitive trans-spinale (rTSMS). Etonnement, peu d’études ont exploré cette thérapie dans le cadre des LMTs, et rare sont celles qui l’ont utilisé d’une manière focale, c’est à dire directement au niveau du site de la lésion. A ce jour, les mécanismes et les voies sous-jacentes de ces effets dans ce cadre restent toujours inconnus. C’est pourquoi nous avons entrepris de caractériser ces effets dans le cadre de mes travaux de Thèse. En effet, en premier lieu, nous avons évalué les effets de la rTSMS sur la réparation tissulaire, via la modulation de la cicatrice médullaire et de ces différentes composantes in vivo, ainsi que sur la récupération fonctionnelle dans différents paradigmes (aigue et chronique) et à différents âges (juvénile, adulte et vieux) chez des souris WT ayant subi une transsection complète de la moelle spinale. En second lieu, l’objectif était de décrire les mécanismes à l’origine des effets de la rTSMS. Pour ce faire, des analyses protéomiques ont été réalisées, puis nous avons évalué l’effet de la rTSMS sur la réactivité des cellules souches endogènes de la moelle, ainsi que, la contribution de ces dernières dans la mise en place de la cicatrice gliale in vitro et in vivo via un modèle de souris transgénique hFoxJ1-CreER T2 ::tdTomato. L’objectif global était d’étudier, pour la première fois, l’effet de la rTSMS sur la réponse des différentes composantes cellulaires résidentes de la moelle spinale, les mécanismes à l’origine de ces effets, ainsi que la capacité à restaurer les fonctions motrices perdues suite à la lésion médullaire
Spinal cord injury (SCI) leads to a loss of sensitive and motor functions. Currently, there is no therapeutic intervention offering a complete recovery. Here, we report that repetitive trans-spinal magnetic stimulation (rTSMS) can be a noninvasive SCI treatment that enhances tissue repair and functional recovery. Several techniques including immunohistochemical, behavioral, cells cultures, and proteomics have been performed. Moreover, different lesion paradigms, such as acute and chronic phase following SCI in wild-type and transgenic animals at different ages (juvenile, adult, and aged), have been used. We demonstrate that rTSMS modulates the lesion scar by decreasing fibrosis and inflammation and increases proliferation of spinal cord stem cells. Our results demonstrate also that rTSMS decreases demyelination, which contributes to axonal regrowth, neuronal survival, and locomotor recovery after SCI. This research provides evidence that rTSMS induces therapeutic effects in a preclinical rodent model and suggests possible translation to clinical application in humans

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Centenaro, Lígia Aline. "Transplante de lâmina própria olfatória e respiratória após lesão medular em ratos : implicações sobre a recuperação locomotora, hiperreflexia e regeneração axonal." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/117255.

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Lesões medulares resultam em uma perda irreversível da função abaixo do sítio da lesão. Esses comprometimentos são permanentes e ocorrem devido à perda de neurônios localmente e também dos tratos axonais ascendentes e descendentes da medula espinal. Na tentativa de criar um ambiente favorável à regeneração dos axônios lesionados, células da glia embainhante olfatória (GEO) vêm sendo transplantadas como estratégia de tratamento em animais submetidos a diferentes modelos experimentais de lesões medulares. Entretanto, um consenso sobre o potencial terapêutico desse tipo de transplante celular ainda precisa ser estabelecido. O objetivo do presente trabalho foi verificar a eficácia do transplante de lâmina própria (LP) olfatória (que possui células da GEO) e de LP respiratória (desprovido de células da GEO), quando implantadas imediatamente, 2 ou 4 semanas após a realização da transecção da medula espinal. Doze semanas após a realização dos implantes, os animais que receberam LP olfatória e respiratória apresentaram uma melhora sutil na função motora dos membros posteriores. Além disso, o transplante de LP olfatória quando realizado imediatamente após a lesão reduziu a hiperatividade do reflexo de retirada, enquanto o implante desse tipo de tecido 4 semanas pós-lesão produziu uma discreta depressão dependente de frequência do reflexo de Hoffman (um análogo elétrico do reflexo monossináptico de estiramento). Nas diferentes janelas terapêuticas utilizadas, o transplante de ambos os tipos de LP produziu resultados comparáveis em relação à preservação do tecido medular, brotamento de neuritos e regeneração de fibras mielínicas no local da lesão, indicando que o tempo decorrido antes da realização dos transplantes não parece limitar os efeitos regenerativos. Todavia, as fibras mielínicas observadas no sítio da transecção nos animais que receberam LP olfatória 2 e 4 semanas pós-lesão possuíam menor área, diâmetro e espessura da bainha de mielina quando comparados aos animais que receberam LP respiratória nesses mesmos períodos. O transplante imediato de LP olfatória e respiratória também favoreceu o restabelecimento das conexões entre as fibras axonais lesionadas com núcleos do tronco encefálico e até mesmo com a região do córtex somatossensorial, como indicado pela presença de neurônios nessas regiões marcados positivamente com um marcador axonal retrógrado. Um número maior de fibras positivas para 5-HT foi observado no coto proximal dos grupos transplantados com ambos os tipos de LP em comparação às regiões da lesão e do coto caudal. Fibras positivas para CGRP estavam presentes em número considerável no local da lesão. A recuperação locomotora e a regeneração axonal no local da lesão foram limitadas e comparáveis entre os grupos transplantados nos diferentes tempos com LP olfatória e respiratória, sugerindo que esses resultados não estão exclusivamente relacionados à presença de células da GEO nos enxertos utilizados. Um melhor entendimento sobre o potencial restaurativo desse tipo de transplante é necessário a fim de justificar a aplicação dessa terapia em humanos.
Spinal cord injury (SCI) results in an irreversible loss of function below the injury site. These permanent disabilities occur due to local neuronal death and loss of ascending and descending axons in the spinal cord. In attempt to create a favorable environment for the re-growth of injured axons, olfactory ensheathing cells (OECs) have been transplanted as a treatment strategy in animals submitted to different experimental models of SCI. However, a consensus on the efficacy of this cellular transplantation has yet to be reached. The main focus of the present study was explore the efficacy of olfactory lamina propria (OLP, graft containing OECs) or respiratory lamina propria (RLP, graft without OECs) when transplanted immediately, 2-week or 4-week after spinal cord transection. After 12 weeks of transplantation, animals with OLP and RLP grafts showed a subtle hindlimb motor improvement. Furthermore, the transplantation of OLP when performed immediately after injury reduced the withdrawal reflex over-responsiveness, while the implantation of this tissue 4 weeks post-injury produced a discrete frequency-dependent habituation of the Hoffman reflex (the electrical analogue of the classic tendon jerk reflex). In all therapeutic windows used, both lamina propria grafts produced comparable results for tissue sparing, fibers sprouting and re-growth of myelinated fibers at the lesion site, indicating that delayed transplantation approach does not seem to limit the regenerative effects. However, the myelinated fibers observed at the transection site of animals that received OLP 2 or 4 weeks after injury had a smaller myelinated fiber area, diameter and myelin sheath thickness when compared to those animals transplanted with RLP grafts in the same periods. The immediate transplantation of OLP and RLP also foster limited supraspinal axonal re-connection as shown by the presence of neurons stained by retrograde tracing in brainstem nuclei and in the somatosensory cortex. A larger number of 5-HT positive axons were found in the cranial stump of both lamina propria groups compared to the lesion and caudal regions. CGRP positive axons were present in considerable numbers at the SCI site. The locomotor recovery and axon reparative effects were limited and similar between groups transplanted at different times with OLP and RLP, suggesting that these results could not be exclusively related to OECs. In conclusion, a greater understanding of the restorative potential of these tissue grafts is necessary to strengthen the rationale for application of this treatment in humans.

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Lee, I.-Hui. "On CNS injury and olfactory ensheathing cell engraftment strategies /." Stockholm, 2005. http://diss.kib.ki.se/2005/91-7140-551-8/.

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冼振鋒 and Chun-fung Sin. "Olfactory ensheathing cell transplanation in spinal cord after contusion injury." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B40738930.

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Sin, Chun-fung. "Olfactory ensheathing cell transplanation in spinal cord after contusion injury." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B40738930.

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Dombrowski, Mary A. "Sciatic nerve remyelination and nodal formation following olfactory ensheathing cell transplantation." Yale University, 2008. http://ymtdl.med.yale.edu/theses/available/etd-08092007-114648/.

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Transplantation of olfactory ensheathing cells (OECs) into injured spinal cord results in improved functional outcome through axonal regeneration, remyelination, and neuroprotection. However, because little is known of the fate of OECs transplanted into injured peripheral nerve, their myelin forming potential requires investigation. To study these issues OECs were isolated from the olfactory bulbs of adult green fluorescent protein (GFP)-expressing transgenic rats and transplanted into a sciatic nerve crush lesions. Five weeks to six months after transplantation the nerves were studied histologically and it was determined that GFP-expressing OECs survived in the lesion and distributed longitudinally across the lesion zone. Immunostaining revealed a high density of isoform Nav1.6 at the newly formed nodes of Ranvier which were flanked by paranodal Caspr staining. Immuno-electron microscopy for GFP revealed transplanted OECs form peripheral type myelin. These results indicate that transplanted OECs extensively integrate into transected peripheral nerve, form myelin on regenerated peripheral nerve fibers, and reconstruct nodes of Ranvier with proper sodium channel structure.

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Witheford, Richter Miranda. "Olfactory ensheathing cell mediated mechanisms of neurite outgrowth and axon regeneration." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/963.

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The capacity of the olfactory neuraxis to undergo neuronal replacement and axon targeting following injury, has led to scrutiny concerning the molecular and physical determinants of this growth capacity. This is because injury to the central nervous system, in contrast, leads to permanent disconnection of neurons with targets. Olfactory ensheathing cells (OECs), a specialized glial cell, may contribute to olfactory repair, and have been used to promote recovery from spinal cord injury. However, there mechanisms underlying OEC-induced regeneration are poorly appreciated. To understand these mechanisms, OECs from the lamina propria (LP OECs) or olfactory bulb (OB OECs) were transplanted into a lesion of the dorsolateral funiculus. While both cells demonstrated reparative capacities, LP and OB OECs differentially promoted spinal fibre growth; large-diameter neurofilament-positive, CGRP-positive, and serotonergic fibres sprouted in response to both LP and OB OEC transplantation, whereas substance-P and tyrosine hydroxylase-positive neurons grew more extensively following OB or LP OEC transplantation, respectively. To further understand the growth of spinal cord neurons in response to OECs, a proteomic analysis of OEC secreted factors was performed, identifying secreted protein acidic and rich in cysteines (SPARC) as a mediator of OEC-induced outgrowth in vitro. To test the contributions of SPARC to spinal cord repair after OEC transplantation, cultures of LP OECs from SPARC null and wildtype (WT) mice were transplanted into a crush of the dorsolateral funiculus. Substance P and tyrosine hydroxylase positive axon sprouting was significantly reduced in SPARC null OEC-treated animals, suggesting that individual factors may contribute to OEC-promoted regeneration. To investigate the effect of OECs on corticospinal (CST) neurons, an in vitro assay was developed using postnatal day 8 CST neurons. Coculture of CST neurons with OB OECs produced extensive axon elongation. Application of OB OEC secreted factors increased CST neurite branching, but did not increase axon elongation. In contrast, plating of CST neurons on OB OEC plasma membrane resulted in extensive axon elongation. Furthermore, the OB OEC plasma membrane could overcome CST neurite outgrowth inhibition induced by an outgrowth inhibitor. Together these findings provide insight into OEC mechanisms of neurite outgrowth and axon regeneration.

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Murthy, Manjari. "Regulation of olfactory ensheathing cell development by the transcription factor Runx1." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=117000.

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Olfactory ensheathing cells (OECs) are a unique class of glia in the olfactory system. They exhibit characteristics of both Schwann cells and astrocytes and have the ability to cross the boundary between central (CNS) and peripheral (PNS) nervous systems. The indispensible contributions of OECs to the lifelong regeneration of the olfactory system has identified these cells as promising candidates for cell transplantation therapies to repair CNS injuries. However, initial studies have yielded highly variable results on the suitability of OECs for CNS regeneration strategies. The inherent heterogeneity of OECs is believed to underlie this problem, as only a subpopulation of OECs is thought to have axonal ensheathing properties. Learning how to harness the potential of the right subpopulation has been hindered by the lack of information regarding their specific functions and molecular properties. In this regard, we have previously shown that a particular transcription factor, termed Runx1, is expressed in cells thought to correspond to a subpopulation of OECs in the olfactory bulb (OB) and have set forth to explore its expression pattern and role in this region. We demonstrate Runx1 is preferentially expressed in OECs of the inner olfactory nerve layer (ONL) and molecularly characterization of this subset of cells. Additionally, we show that Runx1 knockdown in vivo perturbs the proliferation of presumptive OEC precursors and leads to an increase in Runx1-expressing OEC precursors, with a parallel decrease in the number of more developmentally mature OECs. Finally, we provide initial evidence suggesting that Runx1 might be involved in the topological organization of Runx1-expressing OECs within the inner ONL of the OB. These results raise the possibility that Runx1 might be involved in OEC fate specification and provide an avenue for further exploration into the molecular mechanisms underlying OEC subpopulation identity, specification and function.
Les cellules olfactives engainantes (COE) sont une classe unique de cellules gliales dans le système olfactif. Elles possèdent certaines caractéristiques antigéniques et fonctionnelles des deux grandes classes de cellules gliales, soit les cellules de Schwann et les astrocytes. De plus, elles peuvent traverser la frontière entre le système nerveux central (SNC) et périphérique (SNP). Les contributions indispensables des COE à la régénération continuelle du système olfactif tout au long de la vie adulte font de ces cellules des candidats extrêmement prometteurs pour les thérapies de transplantation cellulaire pour la régénération du SNC. Toutefois, les études préliminaires ont généré des résultats variables, ce qui remet en question l'utilité thérapeutique des COE. Une telle variation dans les résultats pourrait être causée par l'hétérogénéité des COE. Cette explication est fondée sur l'hypothèse que seules certaines sous-populations de COE auraient le potentiel de régénérer et d'engainer les axones. Cependant, notre compréhension des fonctions et des propriétés moléculaires spécifiques aux sous-populations de COE est limitée, ce qui restreint l'exploitation de leur potentiel. Nous avons déjà établi que le facteur de transcription Runx1 est exprimé spécifiquement dans une population de cellules que nous croyons être les COE dans le bulbe olfactif. Ici, nous montrons que Runx1 est exprimé dans une sous-population de COE dans la région interne de la couche du nerf olfactif (CNO) et nous présentons une caractérisation moléculaire de ces cellules. Nous montrons aussi qu'une diminution du niveau de la protéine Runx1 chez la souris augmente de façon significative la prolifération des COE présomptives et des précurseurs de COE. De plus, nous montrons qu'il y a une diminution concomitante dans le nombre de COE qui ont atteint la maturité développementale. Finalement, nous présentons des évidences initiales qui suggèrent que Runx1 est impliqué dans l'organisation topologique des COE qui expriment Runx1 dans la région interne du CNO. Ces résultats soulèvent la possibilité que Runx1 est impliqué dans la spécification du destin cellulaire des COE. Nous fournissons donc une avenue pour l'exploration future des mécanismes moléculaires qui contrôlent l'acquisition de l'identité, la spécification et la fonction des sous-populations spécifiques de COE.

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Mallek, Jennifer de Toledo. "Hyaluronic acid-olfactory ensheathing cell compositions for spinal cord injury nerve regeneration." [Gainesville, Fla.] : University of Florida, 2006. http://purl.fcla.edu/fcla/etd/UFE0015880.

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Bocking, Sarah. "Role for the transcription factor AML1/Runx1 in Olfactory Ensheathing Cell development." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=92380.

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Cell-intrinsic mechanisms of transcriptional regulation are vital for developing cell heterogeneity. The runt-related gene, Runx1, regulates the development of neurons of the mouse olfactory epithelium. This project's aims were to characterize Runx1-expressing cells in the olfactory bulb and to elucidate the function of Runx1 in those cells. Runx1-expression is restricted to a defined 'band' of cells in the superficial region of the main olfactory bulb (MOB) and to the accessory olfactory bulb. Runx1-expressing cells correspond to olfactory ensheathing cells of the inner olfactory nerve layer (iOECs). Analysis of Runx1-deficient embryos revealed a perturbation of the topology of MOB OECs in which Runx1 is normally expressed. Ectopic Runx1 expression in OEC primary cultures resulted in a decreased number of proliferating cells. These results demonstrate that Runx1 is expressed in a subpopulation of OECs and suggest a role in OEC topology by negatively modulation of their proliferation capacity.
Les mécanismes intrinsèques de regulation de transcription sont requis au développement de l'hétérogénéité cellulaire. Le runt-related gène, Runx1, est impliqué dans le développement des neurons de l'épithélium olfactif. Les buts de ce projet étaient de caractériser les cellules exprimant Runx1 dans les bulbes olfactifs (BO) et de déterminer la fonction de Runx1 dans ces cellules. Les cellules exprimant Runx1 forment un domaine défini dans une des couches superficielle du BO et dans le BO accessoire et ont été identifiées comme étant des "olfactory ensheathing cells" appartenant à la couche intérieure du nerf olfactif (iOECs). Les analyses des iOECs qui n'expriment pas Runx1 suggère une perturbation de leur distribution. L'expression ectopique de Runx1 dans les cultures primaires d'OECs a été associée à une réduction du nombre d'OECs proliferatives. Ces résultats démontrent que Runx1 est exprimé par les iOEC et modifie leur distribution par modulation négative de leur capacité proliférative.

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Ould-Yahoui, Adlane. "Le système MMP/TIMP dans la croissance neuritique et la motilité des cellules souches de la muqueuse olfactive." Thesis, Aix-Marseille 2, 2011. http://www.theses.fr/2011AIX20672.

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Les métalloproteases matricielles (MMPs) appartiennent à une famille d'endopéptidases dépendantes du zinc, présentent sous forme secrétée ou membranaire (MT-MMP) et qui jouent un rôle fondamental dans la signalisation cellulaire. L'activité des MMPs est régulée par leur inhibiteurs endogènes, les inhibiteurs tissulaires des MMPs (TIMPs). Le système MMP/TIMP régule les interactions cellule-cellule et cellule-matrice extra cellulaire et module la motilité cellulaire par clivage protéolytique des composants de la matrice extra cellulaire aussi bien lors de processus physiologiques que dans des situations pathologiques.Dans un premier temps, nous avons mis en évidence le rôle de TIMP-1 dans la modulation de la croissance neuritique et la morphologie neuronale, via l'inhibition de MMP-2 et non de MMP-9. souches de la muqueuse olfactive (OE-MSCs). Nous montrons dans cette étude que les gélatinases MMP-2 et MMP-9 ainsi que la MMP membranaire MT1-MMP, sont impliquées dans la migration des OE-MSCs. Nous montrons également que les gélatinases sont probablement impliquées dans les propriétés neurotrophiques des OE-MSCs et des cellules engainantes olfactives.L'ensemble de ces résultats apporte de nouveaux éléments fondamentaux, dans la compréhension du rôle du système MMP/TIMP dans les processus post-lésionnels qui ont lieu au sein du système nerveux central
The matrix metalloproteinases (MMPs) belong to a growing family of Zn2+-dependent endopeptidases, secreted or membrane-bound (MT-MMP), which play a fundamental role in the cell signalling. The activity of the MMPs is regulated by their endogenous inhibitors, the tissue inhibitors of MMPs (TIMPs). The MMP / TIMP system regulates the cell-cell and cell-extracellular matrix interactions and modulates the cellular motility through the cleavage of protein components of the extracellular matrix, as well during physiological and pathological conditions.Our results suggest that TIMP-1 is implicated in the modulation of the neurite outgrowth and morphology of cortical neurons through the inhibition at least in part, of MMP-2 and not MMP-9. Afterward, we study of the system MMP / TIMP in the migration of the stem cells of olfactory ectomesenchymal stem cells (OE-MSCs). We show that gelatinases MMP-2 and MMP-9 as well as MT1-MMP, are involved in OE-MSCs migration. We also show that gelatinases are probably involved in neurotrophic properties of the OE-MSCs and olfactory ensheathing cells.Altogether, these results provide new evidences on the role of MMP/TIMP system in central nervous system post-lesional processes

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Fairless, Richard. "A comparison of the molecular mechanisms involved in olfactory ensheathing cell and Schwann cell interactions with astrocytes." Thesis, University of Glasgow, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.413375.

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Gueye, Yatma. "Implication de MMP-2 dans les propriétés des cellules engainantes de la muqueuse olfactive et dans la réparation des lésions de la moelle épinière : études in vitro et in vivo." Thesis, Aix-Marseille 2, 2011. http://www.theses.fr/2011AIX20681.

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Lorsque le système nerveux central des mammifères est lésé, un ensemble de réactions secondaires impliquant l’inflammation et une gliose réactive conduit à la formation d’une cicatrice gliale qui inhibe la régénération axonale. Dans le cas d’une lésion de la moelle épinière l’absence de réparation efficace des réseaux axonaux lésés peut conduire à la paraplégie ou à la tétraplégie. Aujourd’hui on estime à plus de 2,5 millions le nombre d’individus dans le monde souffrant de ces handicaps et il n’existe à ce jour aucun traitement validé pour améliorer la situation des patients. Cependant, certaines approches de thérapie moléculaire, cellulaire, et de réadaptation semblent toutefois prometteuses sur modèle animal. La dégradation des chondroitines sulfates protéoglycanes (CSPGs), principales protéines inhibitrices de la cicatrice gliale, par clivage des coeurs protéiques et ou des chaînes latérales glycosaminoglycanes favorise la régénération axonale et entraîne une récupération fonctionnelle. Des études ont montré que la métalloprotéase matricielle MMP‐2 est capable de dégrader le coeur protéique de ces CSPGs. Par ailleurs, les cellules engainantes de la muqueuse olfactive (CEOs) occupent une place privilégiée parmi les types cellulaires proposés dans la thérapie cellulaire en favorisant la croissance axonale et la récupérationfonctionnelle après lésion de la moelle épinière. Cependant, les mécanismes qui sous‐tendent les propriétés régénératrices des CEOs restent essentiellement inconnus. Dans notre Thèse, nous présentons nos travaux en trois parties. Dans la première, nous montrons in vitro que : i) les CEOs en culture primaire secrètent des taux élevés de MMP‐2, au moins en partie active ; ii) les gélatinases MMP‐2 et MMP‐9 présentent une sécrétion vésiculaire golgi‐dépendante; iii) la distribution des vésicules contenant les MMPs est liée à celle du cytosquelette et des moteurs moléculaires qui participent probablement à une sécrétion focalisée de ces molécules en fonction d’interactions entre le milieu extracellulaire et le cytosquelette ; iv) les MMPs peuvent avoir une distribution nucléaire dans les CEOs ; v) MMP‐2 jouerait un rôle dans la migration des CEOs, un processus important dans leurs capacités à réparer le tissu nerveux. Dans la seconde partie de notre thèse, nous avons développé un modèle de cicatrice gliale in vitro et nous montrons que : i) la migration des cellules astrocytaires de la cicatrice gliale in vitro est sensible aux effets des inhibiteurs des MMPs, contrairement aux cellules microgliales ; ii) les CEOs lèvent l’inhibition de croissance axonale due aux cellules astro‐microgiales ; iii) le potentiel des CEOs à créer un environnement permissif à la croissance axonale serait lié aux gélatinases sécrétées par ces cellules, en particulier MMP‐2. Dans la troisième partie de notre Thèse, nous avons évalué in vivo si MMP‐2 contribuait aux effets bénéfiques des CEOs. Nous montrons pour la première fois, dans un model animal d’hémisection de la moelle épinière, et en utilisant des approches anatomiques, électrophysiologiques et d’analyse de la locomotion, qu’une administration chronique de MMP‐2 recombinante : i) augmente le nombre et le diamètre des axones du coté distal du site de lésion ; ii) restaure la réponse évoquée du reflexe‐H distal au site de lésion ; iii) améliore la réponse respiratoire à la fatigue musculaire induite électriquement et, iv) le plus important, améliore la récupération de la locomotion. L’ensemble de notre travail suggère que MMP‐2 sécrétée par les CEOs jouerait un rôle important des les propriétés bénéfiques de ces cellules lorsqu’elles sont transplantées dans des sites de lésions de la ME, et que cette MMP présente un réel potentiel thérapeutique qui reste à explorer
When the mammalian central nervous system is injured, a set of secondary reactions involving inflammation and reactive gliosis leads to the formation of a glial scar that inhibits axonal regeneration. In the case of a spinal cord lesion, the lack of effective repair of injured axonal networks can lead to paraplegia or quadriplegia. Today it is estimated that more than 2.5 million people are suffering from these handicaps worldwide, and there is as yet no validated treatment to improve the situation of patients. However, based on animal models, some molecular, cellular, and rehabilitation therapy approaches seem promising. Degradation of chondroitin sulfate proteoglycan (CSPG), the main inhibitory protein of the glial scar, by cleavage of either the protein core or side chains glycosaminoglycans, promotes axonal regeneration and leads to functional recovery. Studies have shown that the matrix metalloproteinase MMP-2 is capable of degrading the core protein of the CSPG. In addition, olfactory mucosa ensheathing cells (OECs) represent the most promising cell type for promoting axonal growth and functional recovery after spinal cord injury. However, the mechanisms underlying the regenerative properties of OECs remain essentially unknown. Here, we present our work in 2 parts. First, we show in vitro that: i) OECs in primary culture secrete high levels of active MMP-2; ii) both gelatinases, MMP-2 and MMP-9, have a vesicular Golgi-dependent secretion; iii) the distribution of vesicles containing the MMPs is linked to cytoskeleton and molecular motors distribution, which are probably involved in focused secretion of these molecules; iv) MMPs may have a nuclear distribution in OECs; v) MMP-2 plays a role in the migration of EOCs, an important process in their ability to repair nerve tissue. In the second part of my work, we evaluated whether the MMP-2 contributed to the beneficial effects of EOCs. We used an in vivo approach and we show for the first time, in an animal model of hemisection of the spinal cord, and using anatomical, electrophysiological analysis of locomotion approaches, that a chronic administration of recombinant MMP-2: i) increases the number and diameter of axons in the distal side of the site of injury; ii) restores the response-evoked H-reflex distal to the lesion site, iii) enhances the respiratory response to electrically-induced muscle fatigue, and iv) most importantly, improves the recovery of locomotion. All our work suggests that MMP-2, secreted by the EOCs, plays an important role in the recovery properties of these cells, when transplanted into spinal cord lesions, and that this MMP has a real therapeutic potential that remains to be explored

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Honoré, Axel. "Effet des Cellules Gliales Olfactives issues des Bulbes Olfactifs sur les cellules souches épendymaires et leur progénie après une lésion médullaire." Thesis, Normandie, 2017. http://www.theses.fr/2017NORMR060/document.

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Les lésions médullaires traumatiques (LMT) conduisent à une atteinte des voies nerveuses sensitives et motrices. Leur taux de mortalité reste très élevé, d'où la nécessité de trouver de nouveaux traitements. Les Cellules Gliales Olfactives (CGOs) représentent un candidat intéressant de par leur fonction au sein du système olfactif primaire. La découverte d'une population de cellule souche neurale bordant le canal central de la moelle spinale (MS) adulte, appelées cellules épendymaires, suscite un nouvel espoir dans le domaine des biothérapies. Ce travail de thèse a permis d'étudier l'effet d'une transplantation de CGOs sue le comportement des cellules résidentes de la moelle spinale et notamment les cellules souches épendymaires qui, en association avec les astrocytes et les péricytes, participent aux mécanismes de guérison des LMT. L'utilisation du modèle murin hFoxJ1-CreERT2::YFP (permettant le suivi spécifique des cellules épendymaires et de leur progénie), a montré que les CGOs augmentaient in vitro le potentiel d'auto-renouvellement des cellules souches de la MS et modifiaient leur voie de différenciation vers un type neural. In vivo, la transplantation de CGOs augmente la prolifération des cellules épendymaires ainsi que leur différenciation en astrocytes hypo-réactifs conduisant à la formation d'un environnement post-lésionnel bénéfique à la survie neuronal et l'établissement d'une neurogenèse. Nos travaux ont montré pour la première fois que la transplantation de CGOs après LMT permettait la génération de nouveaux neurones. Ceci constitue un nouvel espoir dans l'établissement de stratégies thérapeutiques pour le traitement des LMT chez l'Homme
The spinal cord injuries (SCI) lead to the damages of the spinal cord or nerves and often cause permanent changes in body functions leading to the death. Cell therapies have raised great hope for regenerative medicine. Clinical data showed that the olfactory ensheathing cells (OECs) enhanced functional recovery after SCI and could be a very attractive therapeutic approach. Moreover, the discovery of a new endogenous resident stem cell population, lining the central canal of the spinal cord, named ependymal stem cells, represents a new hope for the therapy. This thesis analyzed the role of OECs transplantation, on the behaviour of ependymal stem cells since these cells, together with astrocytes and pericytes significantly contribute to the recovery of SCI. The use of the mouse model hFoxJ1-CreERT2::YFP (allowing to specifically follow the ependymal stem cells ant their progeny) showed that OECs increased in vitro the self-renewal potential of spinal cord stem cells and modified their differentiation pathway towards a neural type. In vivo, OECs transplantation significantly increases the proliferation of ependymal cells and their differenciation into hypo-reactive astrocytes leading to the formation of a beneficial environment to neuronal survival and the neurogenesis establishment. Our results also showed for the first time that OECs transplantation after SCI allows the generation of new neurons by non-ependymal cell-derived progenitors. These results represent a new hope in the establishment of therapeutic strategies for the treatment of SCI in humans

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