Gotowa bibliografia na temat „Mouse PSCs”

Generation of kidney organoids from pluripotent stem cells (PSCs) is regarded as a potentially powerful way to study kidney development, disease, and regeneration. Direct differentiation of PSCs towards renal lineages is well studied; however, most of the studies relate to generation of nephron progenitor population from PSCs. Until now, differentiation of PSCs into ureteric bud (UB) progenitor cells has had limited success. Here, we describe a simple, efficient, and reproducible protocol to direct differentiation of mouse embryonic stem cells (mESCs) into UB progenitor cells. The mESC-derived UB cells were able to induce nephrogenesis when co-cultured with primary metanephric mesenchyme (pMM). In generated kidney organoids, the embryonic pMM developed nephron structures, and the mESC-derived UB cells formed numerous collecting ducts connected with the nephron tubules. Altogether, our study established an uncomplicated and reproducible platform to generate ureteric bud progenitors from mouse embryonic stem cells.

Pluripotent stem cells (PSCs), which can self-renew and give rise to all cell types in all three germ layers, have great potential in regenerative medicine. Recent studies have shown that PSCs can have three distinct but interrelated pluripotent states: naive, formative, and primed. The PSCs of each state are derived from different stages of the early developing embryo and can be maintained in culture by different molecular mechanisms. In this review, we summarize the current understanding on features of the three pluripotent states and review the underlying molecular mechanisms of maintaining their identities. Lastly, we discuss the interrelation and transition among these pluripotency states. We believe that comprehending the divergence of pluripotent states is essential to fully harness the great potential of stem cells in regenerative medicine.

The synaptic terminals of mammalian rod bipolar cells are the targets of multiple presynaptic inhibitory inputs arriving from glycinergic and GABAergic amacrine cells. To investigate the contribution of these different inhibitory receptor types, we have applied the patch-clamp technique in acutely isolated slices of the adult mouse retina. By using the whole-cell configuration, we measured and analyzed the spontaneous postsynaptic currents (PSCs) in rod bipolar cells. The spontaneous synaptic activity of rod bipolar cells was very low. However, when amacrine cells were depolarized by AMPA or kainate, the PSC frequency in rod bipolar cells increased significantly. These PSCs comprised several types that could be distinguished by pharmacological and kinetic criteria. Strychnine-sensitive, glycinergic PSCs were characterized by a mean peak amplitude of −43.5 pA and a weighted decay time constant (τw) of 10.9 ms. PSCs that persisted in the presence of strychnine, but were completely inhibited by bicuculline, were mediated by GABAARs. They had a mean peak amplitude of −20.0 pA and a significantly faster τwof 5.8 ms. Few PSCs remained in the presence of strychnine and bicuculline, suggesting that they were mediated by GABACRs. These PSCs were characterized by much smaller amplitudes (−6.2 pA) and a significantly slower decay kinetics (τw= 51.0 ms). We conclude that rod bipolar cells express at least three types of functionally different inhibitory receptors, namely GABAARs, GABACRs, and GlyRs that may ultimately regulate the Ca2+influx into rod bipolar cell terminals, thereby modulating their glutamate release.

Human and mouse induced pluripotent stem cells (PSCs) are widely used for studying early embryonic development and for modeling of human diseases. Derivation and studying of PSCs from model organisms beyond commonly used mice and rats may provide new insights into the modeling and treating human diseases. The order Carnivora representatives possess unique features and are already used for modeling human-related traits. This review focuses on the technical aspects of derivation of the Carnivora species PSCs as well as their characterization. Current data on dog, feline, ferret, and American mink PSCs are summarized.

Presynaptic nicotinic acetylcholine receptors (nAChRs) are thought to mediate some of the cognitive and behavioral effects of nicotine. The olfactory projection to the amygdala, and intra-amygdaloid projections, are limbic relays involved in behavioral reinforcement, a property influenced by nicotine. Co-cultures consisting of murine olfactory bulb (OB) explants and dispersed amygdala neurons were developed to reconstruct this pathway in vitro. Whole cell patch-clamp recordings were obtained from amygdala neurons contacted by OB explant neurites, and spontaneous and evoked synaptic currents were characterized. The majority of the 108 innervated amygdala neurons exhibited glutamatergic spontaneous postsynaptic currents (PSCs), 20% exhibited GABAergic spontaneous PSCs, and 17% exhibited both. Direct extracellular stimulation of OB explants elicited glutamatergic synaptic currents in amygdala neurons. Antibodies to nAChR subunits co-localized with an antibody to synapsin I, a presynaptic marker, along OB explant processes, consistent with the targeting of nAChR protein to presynaptic sites of the mitral cell projections. Hence, we examined the role of presynaptic nAChRs in modulating synaptic transmission in the OB–amygdala co-cultures. Focal application of 500 nM to 1 μM nicotine for 5–60 s markedly increased the frequency of spontaneous PSCs, without a change in the amplitude, in 39% of neurons that exhibited glutamatergic spontaneous PSCs (average peak fold increase = 125.2 ± 33.3). Nicotine also enhanced evoked glutamatergic currents elicited by direct stimulation of OB explant fibers. Nicotine increased the frequency of spontaneous PSCs, without a change in the amplitude, in 35% of neurons that exhibited GABAergic spontaneous PSCs (average peak fold increase = 63.9 ± 34.3). Thus activation of presynaptic nAChRs can modulate glutamatergic as well as GABAergic synaptic transmission in the amygdala. These results suggest that behaviors mediated by olfactory projections may be modulated by presynaptic nAChRs in the amygdala, where integration of olfactory and pheromonal input is thought to occur.

In pancreatic ductal adenocarcinoma (PDAC), the tumor stroma constitutes most of the cell mass and contributes to therapy resistance and progression. Here we show a hitherto unknown metabolic cooperation between pancreatic stellate cells (PSCs) and tumor cells through Interleukin 17B/Interleukin 17B receptor (IL-17B/IL-17RB) signaling. Tumor-derived IL-17B carrying extracellular vesicles (EVs) activated stromal PSCs and induced the expression of IL-17RB. PSCs increased oxidative phosphorylation while reducing mitochondrial turnover. PSCs activated tumor cells in a feedback loop. Tumor cells subsequently increased oxidative phosphorylation and decreased glycolysis partially via IL-6. In vivo, IL-17RB overexpression in PSCs accelerated tumor growth in a co-injection xenograft mouse model. Our results demonstrate a tumor-to-stroma feedback loop increasing tumor metabolism to accelerate tumor growth under optimal nutritional conditions.

Interleukin-11 (IL11) is important for fibrosis and inflammation, but its role in the pancreas is unclear. In pancreatitis, fibrosis, inflammation and organ dysfunction are associated with pancreatic stellate cell (PSC)-to-myofibroblast transformation. Here, we show that IL11 stimulation of PSCs, which specifically express IL11RA in the pancreas, results in transient STAT3 phosphorylation, sustained ERK activation and PSC activation. In contrast, IL6 stimulation of PSCs caused sustained STAT3 phosphorylation but did not result in ERK activation or PSC transformation. Pancreatitis factors, including TGFβ, CTGF and PDGF, induced IL11 secretion from PSCs and a neutralising IL11RA antibody prevented PSC activation by these stimuli. This revealed an important ERK-dependent role for autocrine IL11 activity in PSCs. In mice, IL11 was increased in the pancreas after pancreatic duct ligation, and in humans, IL11 and IL11RA levels were elevated in chronic pancreatitis. Following pancreatic duct ligation, administration of anti-IL11RA to mice reduced pathologic (ERK, STAT, NF-κB) signalling, pancreatic atrophy, fibrosis and pro-inflammatory cytokine (TNFα, IL6 and IL1β) levels. This is the first description of IL11-mediated activation of PSCs, and the data suggest IL11 as a stromal therapeutic target in pancreatitis.

Objective: Activation of pancreatic stellate cells (PSCs) is detrimental to pancreas function by promoting pancreatic fibrosis. Resveratrol is a natural and pharmacologically active compound. This study is to investigate the effect of resveratrol on the bilogical behavior of PSCs under high glucose condition.Methods: Isolated primary mouse PSCs were cultured in low glucose ( 5.5 mmol/L glucose, LG group ) medium, high glucose ( 25 mmol/L glucose, HG group ) medium and treated with resveratrol ( 25 μmol/L or 50 μmol/L). Cell proliferation was examined using MTT assay. The expression of α-SMA and collagen I were determined using Western blotting. Alpha-SMA expression was also determined using immunocytochemistry staining. IL-1, IL-6, and TNF-α mRNA levels and secretion levels in media of PSCs were determined using qRT-PCR and ELISA respectively.Results: Cell Proliferation, α-SMA and collagen I expression levels, IL-1, IL-6, and TNF-α mRNA levels and secretion levels of PSCs were increased after high glucose treatment, compared with low glucose treatment. They were significantly decreased in PSCs treated with both high glucose and resveratrol, compared with high glucose treatment.Conclusion: Resveratrol inhibited high glucose induced PSCs proliferation, activation，cytokine expression and secretion in PSCs. Therefore, resveratrol can be potentially used in therapy of diseases such as type 2 diabetes mellitus (T2DM), pancreatitis and pancreatic cancer where PSCs is activated by high glucose.

CCK receptors are expressed on pancreatic cancer epithelial cells, and blockade with receptor antagonists decreases tumor growth. Activated pancreatic stellate cells or myofibroblasts have also been described to express CCK receptors, but the contribution of this novel pathway in fibrosis of the pancreatic cancer microenvironment has not been studied. We examined the effects of the nonselective CCK receptor antagonist proglumide on the activation, proliferation, collagen deposition, differential expression of genes, and migration in both murine and human PSCs. CCK receptor expression was examined using western blot analysis. Collagen production using activated PSCs was analyzed by mass spectroscopy and western blot. Migration of activated PSCs was prevented in vitro by proglumide and the CCK-B receptor antagonist, L365,260, but not by the CCK-A receptor antagonist L365,718. Proglumide effectively decreased the expression of extracellular matrix-associated genes and collagen-associated proteins in both mouse and human PSCs. Components of fibrosis, including hydroxyproline and proline levels, were significantly reduced in PSC treated with proglumide compared to controls. CCK peptide stimulated mouse and human PSC proliferation, and this effect was blocked by proglumide. These investigations demonstrate that targeting the CCK-B receptor signaling pathway with proglumide may alter the plasticity of PSC, rendering them more quiescent and leading to a decrease in fibrosis in the pancreatic cancer microenvironment.

Pluripotent stem cells (PSCs: ESCs and iPSCs) provide an excellent model system for studying neural development and function. These cells also serve as a reliable source of cell replacement for the treatment of various neurodegenerative diseases and disorders. In view of these applications of PSCs, multiple protocols have been developed to direct their differentiation into neural lineage. However, many of these protocols are limiting in terms of (a) low efficiency of generation of neural cells after long-term culture, (b) requirement of exogenous factors to induce and enhance neural differentiation and (c) supplementation of PSC culture medium with serum. Therefore, in the present study, attempts were made to achieve enhanced efficiency of neural differentiation of PSCs in the absence of exogenous molecules by employing a defined culture medium containing knockout serum replacement (KSR). KSR-based culture system was tested with our in-house-derived EGFP-transgenic ‘GS-2’ ES-cell and ‘N9’ iPS-cell lines and the wild-type ‘D3’ ES-cell line. In KSR medium, PSC-derived EBs predominantly generated neural cells from their post-attachment outgrowths and the complexity of neural networks increased as the culture progressed. Molecular phenotyping of PSC-derived neural cells was performed based on the expression of neural markers both at the mRNA and protein levels. qPCR analysis revealed the expression of markers corresponding to multiple neural cell types, including glutamatergic, GABAergic, cholinergic, serotonergic and dopaminergic neurons, astrocytes and oligodendrocytes, at various time points during the culture. RNA expression studies were confirmed via immunocytochemical analysis of the expression of neural markers. On day 15 of culture, FACS quantitation revealed the efficient generation of NES+ neural progenitors (~16-18%), MAP2+ mature neurons (~12-26%) and GFAP+ astrocytes (~30-63%) from the three PSC lines. Functional assessment of the generated neurons was performed by electrophysiological analysis of passive (RMP) and active (threshold, amplitude, FWHM and outward and inward currents) membrane properties. In order to investigate the role of default pathway in neural differentiation of PSCs in KSR medium, various strategies were employed. GS-2 ES-cells were cultured in the presence of different serum-free supplements; predominant differentiation into neural lineage was achieved in the B27-supplemented medium. The supplementation of KSR medium with BMP4 failed to show any effect of neural differentiation of GS-2 ES-cells. Also, EBs were switched between KSR- and FBS-supplemented culture conditions on day 2 or day 5 of culture. These experiments indicated that KSR medium promoted the generation of neural cell fates at the expense of differentiation to non-neural lineages. Interestingly, differentiation of P19 EC-cells in KSR medium also resulted in the predominant neural differentiation. These experiments collectively suggested the importance of default pathway in neural differentiation of PSCs in KSR medium. Additionally, efforts were made to enrich PSC-derived neural cells and also to enhance the efficiency of neural differentiation of PSCs. The removal of central EB-core from its peripheral neural outgrowth via scooping resulted in the enrichment of neural cells by ~1.3-2.1 folds. Significant increases were observed in the percentages of GS-2 ES-cell-derived MAP2+ mature neurons and GFAP+ astrocytes. Also, FGF2 supplementation of KSR medium was tested as a strategy to achieve enhanced efficiency of neural differentiation. Preliminary studies suggested an increase in the percentage of NES+ neural progenitors in the presence of FGF2. Taken together, KSR-based culture system offers a simple, defined and efficient method to achieve neural differentiation of PSCs in short time duration in the absence of exogenous factors. KSR-based culture system can be employed to generate specific neural cell types, study molecular regulation of neural differentiation and in disease modeling. Also, it can be used to develop a platform for high-throughput screening of potential neurogenic molecules and for dissecting their mechanisms of action.

Pluripotent stem cells (PSCs) are specialized cells, which have remarkable ability to maintain in an undifferentiated state and are capable of undergoing differentiation to three germ-layer lineage cell types, under differentiation-enabling conditions. PSCs include embryonic stem (ES)-cells, embryonal carcinoma (EC)-cells and embryonic germ (EG)-cells. ES-cells are derived from the inner cell mass (ICM) of day 3.5 blastocysts (mouse). On the other hand, EC- and EG-cells have different source of origin and exhibit some differences in terms of their differentiation abilities and culture requirements. These PSCs act as an ideal in-vitro model system to study early mammalian development and cell differentiation and, they could potentially be used for experimental cell-based therapy for a number of diseases. However, one of the problems encountered is the immune rejection of transplanted cells. For this, immune-matched induced pluripotent stem (iPS)-cells have been derived from somatic cells, by forced expression of a few stemness genes. Although, human PSCs lines are being experimented, their cell-therapeutic potential is still far from being thoroughly tested due to lack of our understanding regarding lineage-specific differentiation, homing and structural-functional integration of differentiated cell types in the host environment. To understand these mechanisms, it is desirable to have fluorescently-marked PSCs and their differentiated cell-types, which could facilitate experimental cell transplantation studies. In this regard, our laboratory has earlier generated enhanced green fluorescent protein (EGFP)-expressing FVB/N transgenic ‘green’ mouse: GU-3 line (Devgan et al., 2003). This transgenic mouse has been an excellent source of intrinsically green fluorescent cell types. Recently, we have derived a ‘GS-2’ ES-cell line from the GU-3 mouse line (Singh et al., 2012). Additionally, we envisaged the need for developing an iPS-cell line from the GU-3 mouse and then use them for studying cell differentiation. Thus, aims of the study described in the thesis are to: (1) develop an experimental system to derive EGFP-expressing fluorescently-marked iPS-cell line from a genetically non-permissive FVB/N mouse strain, characterize the established iPS-cell line and achieve differentiation of various cell types from EGFP-expressing iPS-cell line; (2) to study differentiation phenomenon, in particular to cardiac lineage, using select-cardiogenesis modulators and (3) to assess the gene-expression profiles and signaling system associated with cardiomyocyte differentiation of PSCs. This thesis is divided into four chapters with the 1st chapter being a review of literature followed by three data chapters. In the chapter I of the thesis, a comprehensive up-to¬date review of literature is provided pertaining to PSCs, their classification, derivation strategies especially for reprogramming of somatic cells for iPSC generation, their differentiation potential and characterization, particularly to cardiac lineage. Various molecular regulators involved in cardiac differentiation of PSCs with emphasis on epigenetic regulation involving DNA methylation and signaling pathways involved are described in detail. Subsequently, various approaches used for enhanced cardiac differentiation of PSCs and the therapeutic potential of PSC-derived differentiated cell types to treat disease(s) are discussed. Chapter-II describes the successful establishment of a permanent iPS-cell line (named ‘N9’ iPS-cell line) from the non-permissive FVB/N EGFP-transgenic GU-3 ‘green’ mouse. This chapter provides results pertaining to detailed derivation strategy and characterization of the ‘N9’ iPS-cell line which includes colony morphology, expansion (proliferation) efficiency, alkaline phosphatase staining, pluripotent markers’ expression analysis by qPCR and immunostaining approaches and karyotyping analysis. Further, in order to thoroughly assess the differentiation competence of the ‘N9’ iPS¬cell line, assessment of in-vitro and in-vivo differentiation potential of the ‘N9’ iPS-cell line by embryoid body (EB) formation and teratoma formation in nude mice and its detailed histological analysis showing three germ layer cell types and their derivatives were performed, followed by the generation of chimeric blastocysts by aggregation method. This established N9 iPS-cell line could potentially offer a suitable model system to study cardiac differentiation along with other established PSC lines such as the GS-2 and D3 ES-cell lines and the P19 EC-cell line. Following the establishment of the system to study cardiac differentiation of PSC lines, efforts were made to understand the biology of cardiac differentiation of PSCs (wild¬type and EGFP-transgenic PSC lines and P19 EC-cell line) using small molecules as modulators. Data pertaining to this is described in Chapter-III. The possible involvement of epigenetic regulation of cardiogenesis for example, DNA methylation changes in cardiogenesis-associated genes is studied using 5-aza cytidine as one of the chromatin modifiers. In order to understand the cardiac differentiation phenomenon, as a consequence of using 5-aza cytidine in cell culture, it was important to investigate its ability to induce/mediate cardiac differentiation. This involved an assessment by quantitating the cardiac beating phenotype and correlating this with enhanced cardiac-gene expression profiles. Further, DNA methylation regulation of cardiogenesis¬associated genes is described using various DNA methylation analysis techniques. Moreover, the possible involvement of other signaling members in mediating the cardiac differentiation is also studied using the P19 EC-cells. Results pertaining to the above findings are described in detail in the Chapter-III. Chapter-IV is focused on various efforts made towards investigating the ability of ascorbic acid to enhance cardiac differentiation of mouse ES-cells (GS-2 and D3 lines). Ascorbic acid has been implicated to be influencing cardiogenesis and it is reported to enhance differentiation of various cell types under certain culture conditions. Results pertaining to enhancement of cardiac differentiation of PSCs using ascorbic acid are presented in this chapter. This included assessment by quantitating cardiac beating phenotype and its correlation with enhanced cardiogenesis-associated gene expression profiles. Besides, estimation on the sorted cardiomyocyte population, derived from PSCs was also made using mature-cardiac marker. The possible underlying signaling mechanism involved was also studied in detail, using specific inhibitors for pERK (U0126), integrin signaling (pFAK; PP2) and collagen synthesis (DHP), in order to ascertain their involvement in ascorbic acid-mediated cardiac differentiation of mouse ES-cells. Subsequent to the three data chapters (II-IV), separate sections are provided for ‘Summary and Conclusion’ and for ‘Bibliography’, cited in the thesis. The overall scope of the study has been to understand the basic biology of cardiac differentiation from PSCs (EC-cells, iPS-cells and transgenic and wild-type ES-cells) and to assess, by using certain small molecules, whether PSCs could be coaxed to enhance the differentiation to a particular cell type (cardiac). The data contained in this thesis addresses the above theme.

The L1 and L2 capsid proteins of papillomaviruses are characterized by the ability to self- assemble into viral capsids, which can be divided into pseudovirions (PsVs) and virus-like particles (VLPs) by inner content. In addition to the fact that such particles can serve as "nano-containers" for diagnostic and therapeutic agents, it has also been shown that papillomaviruses, whether wild, PsVs or VLPs have a higher affinity for tumor tissue than non-tumor tissue. This thesis deals with relatively newly discovered (2011) mouse papillomavirus (MusPV) and nanoparticles derived from this virus. This papillomavirus has been chosen for its positives, including easy preparation of VLPs and PsVs, as well as an available model organism for possible testing. Furthermore, MusPV has the potential for use in gene therapy and cancer diagnosis, because there is no immune response in the human population. The aim of this diploma thesis is to prepare an expression system for the production of PsVs and VLPs. In additional it will also look at the quality and quantity of PsVs and VLPs, characterization of these particles and verification of existing postulates regarding higher affinity of papillomaviruses for tumor cells. Finally, it will also to verify whether the same effect is observed in MusPV. In the results of...

The most affected cell types in cerebellar ataxias are the cerebellar neurons, which are not readily accessible for cellular and molecular investigation. Pluripotent stem cell (PSC) technology has emerged as an important tool for generating diverse types of neurons, which are used in order to better understand the human nervous system development and pathologies. In this chapter, the strategies for the differentiation of human PSCs toward cerebellar neurons are overviewed, followed by an outlook of their further optimization and diversification by implementing the knowledge from cerebellar development and new cell culture approaches. The optimization stategies are based on the recent progress made in defining the cell populations in mature and developing mouse and human cerebellum. The cellular phenotypes and organization in mouse and human cerebellum are briefly presented, followed by an overview of our current knowledge about their development, which includes pattering, proliferation, neurogenesis, gliogenesis, migration, connectivity and maturation. To date, however, relatively few studies have used induced PSCs (iPSCs) to model cerebellar ataxias and even fewer have looked directly to cerebellar neurons. The reported iPSC-derived in vitro models for cerebellar ataxias are reviewed, followed by an outlook of how to improve these models by generating and exporing the cerebellar neurons.