Dissertations / Theses on the topic 'Mitochondria'
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Jugé, Romain. "Étude de la dynamique mitochondriale dans des cellules cutanées humaines : Mise en place de modèles pour des applications en cosmétologie." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEN007.
Full textThe skin is a specialized type of epithelium, both vital and fragile, which evolves with age and is continuously exposed to environmental stresses, such as solar radiations. While data is available about the response of the mitochondrial network and the fate of damaged mitochondria after chemical or environmental stresses in numerous experimental systems, little is known about these processes in skin cells. The aim of the present thesis was to study the impact (i) of UVB irradiation on mitochondrial dynamics (especially mitochondrial fragmentation) in normal human epidermal keratinocytes, which represent the first line of defence against environmental insults; (ii) of poisoning mitochondria of keratinocytes and normal human fibroblasts with chemical drugs. In a first axis, we developed an original method (called Mitoshape) based on confocal microscopy, to estimate qualitatively and quantitatively the morphology of the mitochondrial network within live cells following UVB irradiation. Using this technology, we demonstrated that UVB irradiation induces mitochondrial fragmentation in normal human keratinocytes, and studied the biochemical actors involved in this response. In a second axis, we showed that the use of mitochondrial poisons could damage mitochondria of keratinocytes and normal human fibroblasts and induce bulk autophagy, although it is not possible to formally rule out the involvement of a PINK1/PARKIN-dependent pathway of mitophagy. In addition to its fundamental interest, this work (performed in collaboration with the cosmetic company SILAB in the context of a CIFRE PhD fellowship from ANRT) paves the way for the screening of novel bioactive agents able to protect and restore mitochondria following stresses
Mortz, Mathieu. "Flexibilités bioénergétique et génomique mitochondriales chez l’oiseau." Thesis, Lyon, 2019. https://n2t.net/ark:/47881/m6v40tjz.
Full textBirds are endotherms that exhibit a remarkable metabolic flexibility in response to energetic constraints related to their lifestyles. This flexibility is notably involved during nutritional transitions in order to adjust metabolic intensity to the available energy resources, a prerequisite for survival. Mitochondria, that produce most of cellular ATP production, are involved in the modulations observed during a fast and during refeeding. The aim of this thesis was to investigate the flexibility of mitochondrial functions in response to fasting and refeeding in Muscovy ducks (Cairina moschata). Several aspects, ranging from bioenergetics and anatomical organization to genomics and evolution of species, were analysed to better understand the modulations involved to adjust mitochondrial functioning to energy constraints. A first study described the kinetics of the installation of fasting-induced muscle hypometabolism and the associated improved mitochondrial bioenergetics efficiency and showed that maximum acclimation was reached after 3 days. Mitochondrial networks remodelling, investigated by antibodies (Western blot) and confocal microscopy, showed a bidirectional flexibility with an increased fusion at the beginning of the fast preceding an increased fragmentation observable after 4 days of fasting. A second study suggested the potential involvement of a nitric oxide synthase (NOS) activity detected in mitochondrial fractions in the modulations of mitochondrial bioenergetics induced by fasting. The activity of mitochondrial NOS was found to be increased by fasting and its in vitro modulation mimicked the effects induced by fasting in nourished birds, in a rapid and reversible manner. A third study explored the flexibility of the mitochondrial genome in order to detect the presence of open reading frames (ORF) potentially encoding bioactive peptides similar to those described in mammals and that are encoded by small regions included in the 12S and 16S genes. Our genetic analyses demonstrated the presence of ORFs incorporated into the 16S rRNA coding gene of most avian species. The molecular evolution of these ORFs among bird species was found to be similar to that calculated for all mitochondrial genes coding for subunits of the respiratory chain. Among the detected ORFs, some corresponded to those described in mammals (humanin and SHLP6) but others had never been described. A fourth study showed that the very strong nucleotide conservation of ORFs located in the 16S gene, and observed in mammals, birds and terrestrial ectotherms, was not an artifact linked to a constraint imposed by the structure of the encoded rRNA. Indeed, the strong nucleotide conservation was not found on alignments of sequences generated by simulations of evolution that took into account the secondary and tertiary structures of 16S rRNA. In the 3 groups of vertebrates, the ORF coding humanin, a peptide identified in humans, underwent a specific negative selection pressure in order to maintain its amino-acid composition during evolution. In conclusion, this thesis highlighted the remarkable bioenergetics and genomic flexibilities of mitochondrial function in birds, which could contribute to the metabolic adjustments required during nutritional transitions. Our results have also opened up a new field of investigation concerning the putative peptides encoded by the mitochondrial genome and their biological roles remain to be explored
Al, Amir Dache Zahra. "Étude de la structure de l'ADN circulant d'origine mitochondriale." Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTT059.
Full textPlasma transports blood cells with a mixture of compounds, including nutrients, waste, antibodies, and chemical messengers...throughout the body. Non-soluble factors such as circulating DNA and extracellular vesicles have recently been added to the list of these components and have been the subject of extensive research due to their role in intercellular communication. Circulating DNA (cirDNA) is composed of cell-free and particle-associated DNA fragments, which can be released by all cell types. cirDNA is derived not only from genomic DNA but also from extrachromosomal mitochondrial DNA. Numerous studies carried out lately indicate that the quantitative and qualitative analysis of cirDNA represents a breakthrough in clinical applications as a non-invasive biomarker for diagnosis, prognosis and therapeutic follow-up. However, despite the promising future of cirDNA in clinical applications, particularly in oncology, knowledge regarding its origins, composition and functions, that could considerably optimize its diagnostic value, is still lacking.The main goal of my thesis was to identify and characterize the structural properties of extracellular DNA of mitochondrial origin. By examining the integrity of this DNA, as well as the size and density of associated structures, this work revealed the presence of dense particles larger than 0.2 µm containing whole mitochondrial genomes. We characterized these structures by electron microscopy and flow cytometry and identified intact mitochondria in the extracellular medium in vitro and ex vivo (in plasma samples from healthy individuals). Oxygen consumption by these mitochondria was detected by the Seahorse technology, suggesting that at least some of these intact extracellular mitochondria may be functional.In addition, I contributed to other studies carried out in the team, such as studies aiming at evaluating (1) the influence of pre-analytical and demographic parameters on the quantification of nuclear and mitochondrial cirDNA on a cohort of 104 healthy individuals and 118 patients with metastatic colorectal cancer, (2) the influence of hypoxia on the release of cirDNA in vitro and in vivo, and (3) the potential of cirDNA analysis in the early detection and screening of cancer.This manuscript present a recent review on cirDNA and its different mechanisms of release, which go hand in hand with the structural characterization of this DNA, its functional aspects and its clinical applications. In addition, this thesis provides new knowledge on the structure of extracellular mitochondrial DNA and opens up new avenues for reflection, particularly on the potential impact that could have those circulating mitochondria on cell-cell communication, inflammation and clinical applications
Beinat, Marine. "Caractérisation génétique des atteintes hépatiques mitochondriales." Thesis, Paris 5, 2013. http://www.theses.fr/2013PA05T007/document.
Full textGenetic characterization of mitochondrial liver damage
Reinhardt, Camille. "Impact de la voie d’import mitochondrial contrôlée par le complexe AIF/CHCHD4 sur la survie des cellules cancéreuses et la réponse aux traitements anticancéreux." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS542.
Full textIn the vast majority of cases, mitochondria are required for tumorigenesis and also for the tumoral response to signals generated by the microenvironmental factors (e.g. nutrient deprivation, hypoxia) or to the effects of anti-cancer treatments (e.g. chemotherapy, radiotherapy). As almost all mitochondrial proteins are nuclear-encoded and imported into the organelle, specialized import machineries have evolved in order to meet the need for protein import. Among these machineries, the one that operates in the intermembrane space and is controlled by CHCHD4/Mia40, regulates the import of a group of proteins (substrates) that play important roles in survival and stress response. Substrates of CHCHD4/Mia40 are involved in a broad panel of mitochondrial activities that includes the biogenesis of respiratory chain complexes, lipid homeostasis, calcium storage, as well as ultrastructure and mitochondrial dynamics. This thesis program was dedicated to the study of the CHCHD4/Mia40 import pathway in cancer cells, with a particular interest for one of the CHCHD4/Mia40 substrates that shapes mitochondrial ultrastructure. Using RNA interference approach and recombinant protein overexpression technique, in a colon cancer model, we showed that the expression of this substrate had a crucial effect on proliferation and tumor growth. Our data also involved this protein in the response to anti-cancer treatments. All together, this work opens a new field of investigations that will not only shed new lights on the metabolic plasticity of cancer cells but also help to identify new metabolic biomarkers
Renken, Christian Wolfgang. "The structure of mitochondria /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2004. http://wwwlib.umi.com/cr/ucsd/fullcit?p3141929.
Full textCraig, Elaine. "Protein import into cardiac mitochondria." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ39261.pdf.
Full textEsteves, Pauline. "Etude de l’action anti-tumorale de la protéine mitochondriale UCP2." Thesis, Paris 5, 2014. http://www.theses.fr/2014PA05T024.
Full textDysregulation of cellular metabolism has been associated with malignant transformation. Switching from oxidative phosphorylation (OXPHOS) to glycolysis for ATP production allows cancer cells to be less oxygen dependent, thus favoring invasion processes. Effects on metabolism, and more particularly mitochondria metabolism, thus represent a potential therapeutic target for cancer therapy. Uncoupling protein 2 (UCP2) is a member of UCPs, a subfamily of the mitochondrial carriers. The function of UCP2 is still controversial but we recently showed its role in the modulation of cell metabolism. Therefore, UCP2 is a good candidate to address the crosstalk between metabolic alteration and promotion of cancer progression and invasion. We show that cancer cells overexpressing UCP2 shift their metabolism from glycolysis toward oxidative phosphorylation and become poorly tumorigenic. Altered expression of glycolytic and oxidative enzymes underlies the cell metabolic shift. Moreover, UCP2 overexpression is associated with an increased adenosine monophosphate-activated protein kinase (AMPK) signaling together with a downregulation of hypoxia-induced factor (HIF) expression. In line with our previous observations, UCP2 does not function as an uncoupling protein but rather controls mitochondrial substrate routing. To address UCP2 role in cancer in vivo, we investigate the impact of Ucp2 deletion in two colorectal cancer mice models: a transgenic mice model APCmin/+ and a chemical cancer mice model (azoxymethane + dextran disulfate (AOM-DSS)). These two models are complementary because they allow us to determine if the role of UCP2 in cancer differs in only one genetic background (APC) compared with an inflammatory model (AOM + DSS). We found in those two colorectal cancer models that UCP2 is more expressed in tumors instead of the adjacent healthy mucosa. Deletion of Ucp2 in APCmin/+ mice leads to decrease in animal survival and Ucp2 deletion is associated in both mice models with an increased number of tumors. Altogether the results suggest that tumor initiation could be increased with Ucp2 deletion. UCP2 thus appears as a critical regulator of cellular metabolism with a relevant action against tumor maintenance and malignancy
Ruby, Vincent. "Étude des évènements mitochondriaux impliqués dans le contrôle de l'apoptose par rbf1, l'homologue de drosophile du gène suppresseur de tumeur rb." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLV039/document.
Full textThe gene rb is the first tumor suppressor discovered in humans. Its prevents the appearance of tumors by regulating negatively the cell cycle. The role of pRb in apoptosis is more complex and the molecular mechanisms triggered by this transcription factor are not completely elucidated. There is a rb homologue in drosophila: rbf1. I participated in the characterization of mitochondrial events induced during activation of apoptosis by Rbf1 in a proliferating tissue of this model organism, the wing disc. In this apoptosis pathway, the Debcl protein, the only drosophila pro-apoptotic member of the Bcl-2 family, is activated and induces recruitment and oligomerization of Drp1, the main effector of mitochondrial fission. This triggers the mitochondrial fragmentation and the accumulation of mitochondrial reactive oxygen species (ROS). Both events participate to the transmission of the apoptotic signal. I have also been able to highlight the implication of factors involved in maintaining mitochondrial quality control which ensures the integrity of the mitochondria and, if necessary, triggers the degradation of damaged elements by mitophagy. Finally, I have contributed to the study of the links between translation and apoptosis induced by Rbf1. In this study, we show that the Poly-A Binding Protein (PABP) can suppress the Rbf1-induced notch phenotype in adults while cell death induced during larval stage was not inhibited but increased. These results prompted us to study the compensation mechanisms induced by the translational apparatus, which allowed us to show that a mRNA translation-related mechanism could counteract the loss of tissue resulting from Rbf1-induced apoptosis independently of apoptosis inhibition
Heller, Anne Sabine [Verfasser], and Achim [Akademischer Betreuer] Göpferich. "Targeting mitochondria by mitochondrial fusion, mitochondria-specific peptides and nanotechnology / Anne Sabine Heller. Betreuer: Achim Göpferich." Regensburg : Universitätsbibliothek Regensburg, 2013. http://d-nb.info/103321664X/34.
Full textTheurey, Pierre. "Implication of mitochondria endoplasmic-reticulum interactions in the control of hepatic metabolism." Thesis, Lyon 1, 2015. http://www.theses.fr/2015LYO10104.
Full textThe liver is an essential organ in the control of energetic homeostasis of the human body. Particularly, hepatic metabolism is crucial for glucose and lipid homeostasis. Catabolism and anabolism of both substrates are in constant equilibrium and synergically regulated in regard of nutrient availability and energetic demand. Disruption of this equilibrium, especially in the case of obesity, can lead to hepatic accumulation of lipids, which is a major cause of hepatic insulin resistance (HIR) leading to chronic hyperglycaemia and type 2 diabetes (T2D). The eukaryotic cell is a highly compartmented structure, and in this respect compartmentation of anabolic and catabolic processes is an integral part of managing metabolic pathways together. In this context, the mitochondrion is a key organelle, housing oxidation of lipids, the tricarboxylic acid (TCA) cycle and cellular respiration. In this way, mitochondrial function is a crucial element in maintaining energetic and reductionoxidation state of the cell within physiological ranges, as well in regulating the proper activity of glucose and lipid metabolism for the all body homeostasis. Mitochondrial function is directly regulated by its interaction with the endoplasmic reticulum (ER) via proximity points between the organelles called Mitochondria-Associated-ER-Membranes (MAM). In this context I have participated during my Ph.D. in a work that has shown the importance of mitochondria-ER interactions in insulin signalling and highlighted MAM disruption as a main actor in HIR. Furthermore, I have studied the regulation of MAM in the physiological context of nutritional transition in the healthy and insulin resistant (IR) liver. Particularly, we have shown that MAM disruption induces impaired insulin signalling, while their reinforcement protects against its appearance and restore insulin sensitivity in lipid-induced IR condition. Moreover, we have pointed out a consistent decrease of MAM quantity in the IR liver of ob/ob, high-fat high-sucrose diet (HFHSD) and Cyclophilin D - knock-out (CypD-KO) mice
Boyer, Hélène. "The mamalian circadian clock regulates the abundance and expression of mitochondrial DNA in the nuclear compartment." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEN015.
Full textThe mitochondrial genome is minimal and most of the mitochondrial proteins are encoded in the nuclear genome. Thus, although mitochondrial and nuclear genomes are physically separated in the cell, anterograde (nuclear to mitochondrial) and retrograde (mitochondrial to nuclear) signals are essential for mitochondrial biogenesis to be coordinated with the cellular energetic demands. Those demands are cyclical in nature, and the circadian clock regulates numerous aspects of mitochondrial biology, including the dynamics of fusion and fission that shape the architecture of the mitochondrial network. In murine livers, the network oscillates between fused (during the day) and fragmented structures (during the night). A fused network is associated with a more efficient ATP production whereas fragmentation is associated with elevated mitochondrial ROS levels and mitophagy. In other words, if mtDNA was to ever escape mitochondria, fission would help. Complementation experiments in yeast have shown that mitochondrial DNA (mtDNA) is able to escape from the mitochondria and enter the nucleus. In human cells (HeLa), the intact and full-length mitochondrial genome has been detected in the nucleus. Evolutionary analyses of nuclear inserted mitochondrial sequences (numts) suggest an ongoing process of integration of mitochondrial sequences into the nuclear genome. Also, abundant somatically acquired mitochondrial- nuclear genome fusion events (simts) have been shown to occur in human cancer cells - an extreme context of genomic instability and disrupted circadian rhythms. The availability of mtDNA in the cytoplasm, protected by vesicles, to be taken up by the nucleus is thought to result from mitophagy. As mitophagy and mitochondrial dynamics are regulated by the circadian clock, we investigated whether mtDNA would accumulate in the nuclear compartment as a function of circadian time. We addressed this question in the mouse liver, a differentiate mammalian tissue. This work demonstrates that the nuclear abundance of mtDNA in murine livers is regulated by the circadian clock – with a zenith at the end of the circadian night. Nuclear mtDNA is differentially hydroxymethylated relative to the total mtDNA extracted from the same tissue. Also, circadian clock disruption altered the phase and abundance of nuclear mtDNA. Additionally, we observed that concurrent accumulation of nuclear mtRNA was sensitive to nutritional challenges. Probably, these dynamics are driven by mitochondrial network remodeling dynamics. Increased nuclear presence and insertions of mtDNA in cancer cells or aging tissues, which are often associated with disrupted circadian oscillators- may thus arise from the loss of a physiological rhythm in mitochondrial-network remodeling
Rebelo, Adriana. "Probing Mitochondrial DNA Structure with Mitochondria-Targeted DNA Methyltransferases." Scholarly Repository, 2009. http://scholarlyrepository.miami.edu/oa_dissertations/344.
Full textGaspari, Martina. "Molecular mechanisms for transcription in mammalian mitochondria /." Stockholm : Karolinska institutet, 2006. http://diss.kib.ki.se/2006/91-7357-012-5/.
Full textBlaikie, Frances H., and n/a. "Synthesis and characterisation of probes that influence mitochondrial function." University of Otago. Department of Chemistry, 2008. http://adt.otago.ac.nz./public/adt-NZDU20080212.091116.
Full textSmith, Christopher Paul. "Maintenance of an energized inner mitochondrial membrane." Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1467886731&sid=4&Fmt=2&clientId=18949&RQT=309&VName=PQD.
Full textWredenberg, Anna. "Mitochondrial dysfunction in ageing and degenerative disease /." Stockholm : Karolinska institutet, 2007. http://diss.kib.ki.se/2007/978-91-7357-311-5/.
Full textSmeyers, Mathias. "Structure et fonction du VDAC: aspects phylogénétiques et biochimiques." Doctoral thesis, Universite Libre de Bruxelles, 2005. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210913.
Full textLa première partie du travail consiste à étudier l’évolution des isoformes de VDAC, à déterminer le nombre et les propriétés des isoformes. Nous montrons que les végétaux possèdent plus d’isoformes que les mammifères et que celles-ci sont également moins bien conservées. Nous avons défini trois classes d’isoformes sur base de leur charge nette :faiblement, moyennement ou fortement chargées. Les VDAC fortement exprimés et très bien conservés chez les champignons, les plantes et les animaux sont moyennement chargés. A l’opposé, les isoformes portant les plus hautes charges nettes sont très divergentes et peu exprimées. Ces particularités permettent pour la première fois de comparer les isoformes de groupes évolutivement distants.
Ensuite, pour relier la structure et la topologie du VDAC à sa fonction, nous avons construit un modèle topologique. Il consiste en feuillet bêta de 18 brins antiparallèles reployés de manière à former un tonneau transmembranaire présentant une courte hélice alpha à son extrémité aminoterminale. Le modèle est compatible avec les séquences de VDAC fongiques, végétaux et animaux. Il rend compte des résultats expérimentaux obtenus par spectroscopie infrarouge et par microscopie électronique de cristaux 2D. Enfin, les résultats d’études topologiques et fonctionnelles publiées dans la littérature supportent également notre modèle.
Nos travaux concernant le VDAC32 de Phaseolus coccineus a permis d’améliorer le protocole de purification et d’en obtenir la séquence. La structure et la stabilité du VDAC32 a été étudiée par spectroscopie infrarouge. L’étude de l’orientation du VDAC à l’aide de lumière infrarouge polarisée se base sur des modèles définissant deux angles, alpha et bêta correspondant à l’inclinaison de l’axe du tonneau par rapport à la normale à la membrane et l’inclinaison des brins par rapport à l’axe du tonneau. Nous proposons que l’angle alpha dépend également de l’asymétrie de la protéine. Nos mesures en spectroscopie infrarouge indiquent que la présence du VDAC diminue la température de transition de la membrane et que la structure protéique est sensible à la transition de phase des lipides membranaires. Enfin, nous montrons que la structure du VDAC est modifiée quand le rapport lipides/protéines diminue. L’orientation des brins bêta se rapproche de l’axe et les chaînes latérales des tyrosines deviennent moins ordonnées.
Les VDAC sont insérés dans la membrane mitochondriale qui contient environ 5% de stérols. Certains auteurs ont détecté le VDAC dans les membranes plasmiques. Ces dernières sont beaucoup plus riches en stérols. Nous montrons dans ce travail que le VDAC possède la même fonction dans des membranes contenant 0% ou 5% de stérols alors que sa structure est légèrement modifiée. Par contre, en présence de hautes concentrations en stérols, la fonction du VDAC est sensiblement altérée. Ces résultats suggèrent que le VDAC a des propriétés différentes dans la membrane plasmique et dans l’enveloppe de la mitochondrie.
Doctorat en sciences agronomiques et ingénierie biologique
info:eu-repo/semantics/nonPublished
Chen, Bing. "Gene expression in Neurospora crassa mitochondria: Mitochondrial RNA polymerase and Mauriceville mitochondrial reverse transcriptase /." The Ohio State University, 1997. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487945744575041.
Full textSaunier, Rémy. "Étude des rôles et des partenaires du domaine C terminal de Rpn11, une sous-unité du protéasome 26S, dans la dynamique mitochondriale chez Saccharomyces cerevisiae." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112357/document.
Full textMitochondria are semi-autonomous organelles, which size, shape and number vary in a wide range in almost every eukaryotic cell. They are famous to be the energy producer of the cells. For this purpose, mitochondria are able to fuse and divide. These events of fusion and fission are also known as the mitochondrial dynamic. This phenomenon is highly controlled and answers to many stimuli. Lately, it has been shown that the ubiquitin proteasome system controls the fusion of mitochondria and that a proteasome subunit controls the mitochondrial fission. The ubiquitin proteasome system is a mechanism that relies on many actors: enzymes recognizing the targets of this system, a protein called ubiquitin and a complex called proteasome in charge of the degradation of the targets. Primarily known for the protein degradation, many investigations suggest that this system has other roles. Our previous studies had already shown that the proteasome subunit named Rpn11 controls the fission of mitochondria independently of the proteolytic activities of the proteasome system. The work shown in this manuscript is focused on the mechanism of action of the C-terminus domain of Rpn11 on various cellular processes, including proteasome assembly, control of mitochondrial and peroxisomal fission, yeast lifespan and also the “Proteasome Storage Granule” formation. The in vivo localisation of Rpn11 and the elucidation of its partners on the mitochondrial fission regulation were also investigated
Gu, Mei. "Mitochondrial function in Parkinson's disease and other neurodegenerative diseases." Thesis, University College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322371.
Full textGilkerson, Robert W. "The cristal membrane adapts mitochondrial structure to respiratory function /." view abstract or download file of text, 2002. http://wwwlib.umi.com/cr/uoregon/fullcit?p3072583.
Full textTypescript. Includes vita and abstract. Includes bibliographical references (leaves 102-119). Also available for download via the World Wide Web; free to University of Oregon users.
Williams, Andrew. "Functional and molecular analysis of defects of the mitochondrial respiratory chain." Thesis, The University of Sydney, 1998. https://hdl.handle.net/2123/27688.
Full textKullar, Peter John. "Defining the cellular and molecular mechanism of maternally inherited hearing loss." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/270543.
Full textCartalas, Jérémy. "Characterization of the RNA maturation-degradation machinery in plant mitochondria." Electronic Thesis or Diss., Strasbourg, 2024. http://www.theses.fr/2024STRAJ003.
Full textMitochondria are the site of energy production in eukaryotic cells. Mitochondria have their own transcriptome. In order to generate a mature and efficient transcriptome, a whole range of RNases are required for RNA maturation and degradation. Among these, the MNU2 protein has been characterized as having a role in maturation. But it could also play a role in degradation. During my PhD, I showed that MNU2 could be a hub for a degradosome, interacting with mtPNPase and a polyA polymerase. I generated mnu2 mutants, and in order to characterize its function I adapted new generation sequencing methods and applied them in reverse genetics approaches. My research has shown a decisive role for MNU2 in the definition of 5' monoP ends. It has also shed light on a potential 5'-3' degradation pathway
Logan, Angela. "Production of reactive oxygen species in mitochondria and mitochondrial DNA damage." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609201.
Full textCabrera, Aulestia Francisco Javier. "Treating Cellular Stress and Damage : Use of Healthy Mitochondria Isolated from Donor Cells in the Artificial Mitochondria Transfer / Transplant (Amt/T) to Repair Mitochondrial Disfunction in Differentiated (Peripheral Blood Mononuclear Cells) and Germinal Cells (Oocytes)." Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTT073.
Full textAccording to the endosymbiotic theory, mitochondria is an organelle derived from an ancient alpha-proteobacteria that developed a symbiosis with a eukaryotic ancestor. Mitochondrial DNA (mtDNA) exists in hundreds to thousands of copies in each cell and encodes for 13 structural proteins which are subunits of respiratory chain. Mitochondria generate energy for cellular processes by producing ATP through oxidative phosphorylation. Also, they control other processes as nucleotide and heme syntheses, redox balance, calcium metabolism, waste management (urea and ROS) and apoptosis. mtDNA deletions, point mutations, thymine dimers and mtDNA depletions are strongly related with disease in humans and other mammals. Some mtDNA alterations can arise spontaneously during life spam, other can be inherited by maternal lineage as specific mutations. So, nuclear DNA mutations can produce mitochondrial disorders because while mtDNA encodes 13 proteins, mitochondria need almost 2000 proteins with structural and functional roles. In these cases, a mendelian inheritance pattern can be observed. mtDNA alterations can be produced by exposure to toxic substances or UV and high-energy radiations. mtDNA mutations are cumulative because mitochondria lack reparative mechanisms. Normal and mutant mtDNA can coexist in the same cell, a condition known as heteroplasmy. Heteroplasmy allows the persistence of an otherwise lethal mutation through generations. Mitochondrial disorders can appear as myopathies, cardiomyopathies, lactic acidosis diabetes mellitus, female’s subfertility, lipodystrophy, neuropathies as autism or Alzheimer’s diseases or haematological and renal disorders. Due to heteroplasmy, these disorders can appear with a wide range of intensities, because the mutant mtDNA needed to cause a disorder varies among organisms, among organ systems and within a given tissue, and depends on a delicate balance between ATP supply and demand. Another kind of problem surges at tissues under hypoxemic-related damage, where mitochondria play an important role in cell survival and recovery. Finally, the role played by mitochondria in cancer survival and treatment is focused in many researches.Mitochondrial disorders have not a single treatment. In the most serious cases of inherited mitochondrial diseases, the supportive treatment only improves the life quality slightly. Nowadays, the most of experimental approaches search prevents the clinical manifestations of these diseases by reducing the mutant mtDNA percentage into the oocyte or the early embryo via nuclear transfer. Artificial Mitochondrial Transfer/Transplant (AMT/T) rises as an alternative to many acquired or inherited mitochondrial disorders, both ex vivo, in vitro and in vivo conditions. The present work shows the variation of an AMT/T method -MitoCeption- in a cellular model for in vitro treatment of acquired mtDNA disorder caused by UV Radiation by using Peripheral Blood Mononuclear Cells (PBMCs) and the feasibility of the same method for ex vivo AMT/T to murine oocytes and early embryos. In the in vitro model of cell damage by UV radiation, the main results represent an upgrading in the applications of AMT/T. We showed that PBMCs could be used as a primary allogeneic mixed source of mitochondria. We also showed that these mitochondria can be transferred in a mix from different donors (PAMM) to UVR-damaged, non-adherent primary cells. Additionally, the duration of the MitoCeption protocol was reduced. On the other hand, Mitoception used on murine oocytes and early embryos probed to be a safe method for AMT/T by using human mitochondrial mix (PAMM). Murine 0ocytes’ and embryos’ exogenous mitochondrial content was observed by fluorescence microscopy and exogenous mtDNA was quantified by qPCR and 2ΔCT method. Finally, healthy murine new-borns were obtained by embryo transfer, probing that human mitochondria were removed from murine cells during embryo’s development after implantation
Macchi, Marc. "Contribution à l' étude de la morphogénèse des mitochondries chez la drosophile." Electronic Thesis or Diss., Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4051.
Full textMitochondria are organelles which are a few micrometers long and are originated from the incorporation of an alpha-proteobacteria in the cytoplasm of eukaryotic cells through endosymbiosis. In eukaryotic cells, mitochondria play a central role in ATP production as well as in programmed cell death and in the biosynthesis of many molecules. Mitochondria are highly polymorphic in size and form. Their organization also varies considerably according to the cell type or physiological or pathological state of the cell. In the last two decades, the study of the mechanisms controlling morphogenesis, dynamic of mitochondrial fission and fusion and their physiological roles has become a major research field of mitochondria. In addition, the progress in video-microscopy enable to record mitochondrial dynamics in the cytoplasm of living cells. I participated in the research on the characterization of gene function called Pantagruelian Mitochondria I (PMI), a novel determinant of the mitochondrial morphology that we discovered in Drosophila. PMI, a protein of the inner membrane, is involved in its membrane organization and essential to form tubular mitochondria. I also contributed to the development of experimental tools and protocols to visualize and study the mitochondrial dynamics in living Drosophila embryos. Interestingly, a stereotyped process of mitochondrial remodeling during Drosophila embryogenesis has been found and it raised a question about its role in developmental processes through my work
Meyer, Alain. "Rôle de la mitochondrie et du stress oxydant au cours des myopathies inflammatoires." Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAJ118/document.
Full textInflammatory myopathies are rare autoimmune diseases whose common denominator is muscle weakness and inflammation. Their origin is not known and conventional treatments are partially effective. Using an epidemiological approach, we have shown that the study of incidence and prevalence is an useful tool for identifying determinants of inflammatory myopathies. However, better identification and classification of patients is mandatory to refine the epidemiology of inflammatory myopathies. Using a translational approach, we have shown that, compared with other inflammatory myopathies, perifascicular mitochondrial dysfunctions are a characteristic of dermatomyositis, which play a role in exercise intolerance and in the maintenance of inflammation. These results open up new avenues to better understand and treat inflammatory myopathies
Liu, Dawei. "Target and small molecule discovery for therapeutic innovation in cardiovascular area." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS324.
Full textCyclic adenosine monophosphate (cAMP) production regulates certain aspects of mitochondria function in rodent cardiomyocytes, such as ATP production, oxygen consumption, calcium imports and mitochondrial permeability transition (MPT), but how this cAMP pool is controlled is not well known. In the first part of this thesis, we investigated the expression, localization and activity of several cAMP-degrading enzymes, phosphodiesterases (PDEs), in isolated rodent cardiac mitochondria. PDE2 expression was mainly detected in subsarcolemmal mitochondria, and cGMP-stimulated PDE2 activity was largest than PDE3 and PDE4, their activities were further confirmed in neonatal rat cardiomyocytes by real time FRET analysis. Moreover, the pharmacological inhibition or the cardiac-specific overexpression of PDE2 modulated mitochondrial respiration, mitochondrial membrane potential loss, MPT and calcium import. Thus, cAMP degradation by PDEs represents a new regulatory mechanism of mitochondrial function, and becomes a potential target in cardiovascular diseases therapy.In addition, the recent improvement of anticancer treatment results in an increase in surviving patients, but with a risk of long-term cardiotoxicity. Thus, in the second part of this thesis, we identified cardioprotective molecules from chemical libraries by developing a high throughput screening assay. We identified 6 potent and specific hits and validated them in 3 cellular models. We investigated the mechanisms of actions of each molecule and their cellular impact by using siRNA silencing, western-blot analysis, fluorescent imagery and real-time metabolic analyses. Three molecules could enter rapidly in preclinical and clinical studies in combination with radiation or chemotherapeutic agents for therapeutic development, while other three molecules may require further chemical optimization
Bandiera, Simonetta. "Investigating the existence of a link between mitochondria and microRNAs." Thesis, Paris 5, 2012. http://www.theses.fr/2012PA05T064.
Full textMitochondria are organelles that have a central role in the energetic metabolism of the cell. Although mitochondria express their own genome, they rely on the expression of the nuclear genome for their biogenesis and function. microRNAs (miRNAs) are small non-coding RNAs that associate with Argonaute 2 (Ago2) protein to regulate gene expression post-transcriptionallythrough RNA interference. The ‘classic’ view of RNA interference describes the pairing of miRNAs with complementary binding sites within the 3’untranslated region (3’-UTR) of the target mRNA. We hypothesized that miRNAs might be instrumental to the cross-talk between the nucleus and the mitochondria. In the first part, we assessed the role of miRNAs in the context of a rare genetic disease involving mitochondrial dysfunction. We focused on Friedreich's ataxia, the most frequent of inherited ataxia in Europe, which is caused by reduced expression of the mitochondrial protein frataxin (FXN). Intwo independent cohorts of patients, we discovered that about 90% of patients were homozygous forone specific haplotype of genetic variants of the FXN3'-UTR. By a combination of computational target prediction analysis and co-transfection experiments, we showed that miRNAs, and specifically miR-124, are involved in the regulation of the FXN.We then challenged further the relationship between the miRNAs and mitochondria through questioning their localization at mitochondria. To this end, we studied miRNAs from mitochondrial and cytosolic RNA fractions isolated from the same HeLa cells. We identified a signature of 13 miRNAs specifically enriched in the mitochondrial RNA fraction that we termed ‘mitomiRs’. Through pathway-enrichement analysis, we observed a specific mitochondrial role for mitomiRs, including regulation of ATP synthesis coupled electron trasport. We also provided the evidence of Ago2 protein location inside human mitochondria at the inter-membrane space. Our work sketches miRNAs and Ago2 as a novel layer of the interplay between the nucleus and the mitochondria. We discuss whether mitochondria may be instrumental to RNA interference or a target per se. Our work paves the way to a new field of research, which may unravel therapeutic outcomes to rescue mitochondrial dysfunction
Jeandard, Damien. "Import d'ARN dans les mitochondries de cellules humaines : identification à grande échelle et applications thérapeutiques." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAJ005.
Full textMutations in the human mitochondrial genome are often associated with severe neuromuscular disorders. The first part of my thesis project consisted in the development of a therapeutic strategy based on the mitochondrial import of RNA molecules. I demonstrated that the stable expression of recombinant RNA molecules in human cells induced the decrease of the pathogenic mutation load in mitochondrial DNA. In the second part, I developed a nex method, CoLoC-seq, for the large-scale identification of RNA species localized in the mitochondria. By applying this method to human cells, I confirmed the mitochondrial targeting of some non-coding cytosolic RNAs and identified new potentially imported RNAs. These data will broaden the knowledge on the pathway of RNA targeting into the mitochondria, its mechanisms and regulation, and will allow optimization of the therapeutic strategies based on RNA import
Gutierrez, Cortes Nicolas. "Expression métabolique des polymorphismes mitochondriaux : mutations pathogènes et haplogroupes." Thesis, Bordeaux 2, 2011. http://www.theses.fr/2011BOR21877/document.
Full textMitochondria, intracellular organelles of eukaryotic organisms, provide most of the necessary energy for cellular activity through oxidative phosphorylation, synthesizing ATP (energy source for the cell) by a coupling between the respiratory chain and the ATPsynthase. These energy metabolism reactions are carried out by enzymatic complexes constituted by sub-units coded by both nuclear and mitochondrial DNA. It has been shown that activity defects in these complexes could be responsible for a group of pathologies under the name of mitochondrial cytopathies.One of the fundamental issues of the study of the mechanisms that lead to mitochondrial cytopathies is the understanding of the influence that mitochondrial DNA has over mitochondrial metabolism. Indeed, mitochondria have their own DNA, and mutations in this DNA are classified according to their impact on mitochondrial metabolism: pathological mutations, which have negative consequences on mitochondrial metabolism, and polymorphisms, which are considered to be neutral.In order to study the influence of mtDNA on energy metabolism, I used two different models: cybrid cells carrying mtDNA mutations found in non-syndromic hearing loss patients, and cybrid cells carrying polymorphisms defining haplogroup J.The results gathered in these studies show that the difference between pathological mutations and polymorphisms is not as big as previously believed. Indeed, it depends on several factors, such as the nuclear and mitochondrial genetic backgrounds, as well as the environmental factors, because under the influence of these factors a mutation considered as pathological may become neutral, and a polymorphism considered neutral may become pathological
Addo, Mathew Glover. "Identification of new nuclear genes involved in the mitochondrial genome maintenance." Thesis, Paris 11, 2011. http://www.theses.fr/2011PA112065.
Full textMitochondrial respiratory chain diseases of nuclear origin represent one of the major causes of metabolic disorders. These diseases are characterized by a huge clinical and genetic heterogeneity which is a major problem in identifying the disease causing gene. Although several gene mutations have already been found in some patients or families, the disease causing gene of the majority is yet to be determined. The overall structure and gene content of the mitochondrial genome and the proteins required for mtDNA transactions are largely conserved from yeast to human offering the opportunity to use animal models to understand the molecular basis of mitochondrial dysfunctions. To expand the number of human candidate genes of mitochondrial diseases involved in mtDNA maintenance, we have developed in this study, the nematode Caenorhabditis elegans as a model organism to identify new proteins involved in mtDNA maintenance by combining RNAi and ethidium bromide exposure. We have developed a large-scale screening method of genes required for mtDNA maintenance in the worm and initially indentified four new C. elegans genes (atad-3, dnj-10, polrmt, phi-37 and immt-1) involved in mtDNA stability. The human homologs of these genes (ATAD3, DNAJA3, POLRMT and ATP5A1) can be now considered as candidate genes for patients with quantitative mtDNA deficiencies. Using our screening design we have begun to screen all the C. elegans genes encoding mitochondrial proteins. Of the 721 estimated C. elegans mitochondrial genes homologous to human genes, we have tested 185 genes and found that 41 genes are required for the maintenance of the mitochondrial genome in post mitotic cells. These genes fall into three main functional categories of metabolism, protein synthesis and oxidative phosphorylation. Finally, in this study, we investigated the reversibility of mtDNA depletion with drugs to counteract POLG dificiency. Three molecules, Chlorhexidine, Resveratrol and Bezafibrate, have been tested to restore normal mtDNA content and worm life cycle. These experiments hold promise for future work using C. elegans as a pharmacological model for mitochondrial diseases.Altogether, the data generated in this work is a starting point for promising advances in the mitochondrial field, showing the relevance of the nematode as a model organism to study fundamental processes as well as human health research
André, Fanny. "Influence du métabolisme mitochondrial dans la survie et la mort des cellules tumorales : intérêt du ciblage mitochondrial pour le traitement des cancers." Thesis, Lille 2, 2017. http://www.theses.fr/2017LIL2S001/document.
Full textMitochondria occupies a key role in cancer cells. As the main source of ATP synthesis and the site of anabolic and catabolic reactions, mitochondria support tumor development. Besides, mitochondria are also involved in the response to cellular stress regulating autophagy or cancer cell death.In this context, we have demonstrated that mitochondrial function may alter the ER stress response thus promoting tumor cell survival. Indeed, overexpression of the Glucocorticoid-Induced Leucine Zipper protein (GILZ) protein attenuates endoplasmic reticulum stress mediated cell death. This is achieved by maintaining the mitochondrial network and the increase of mitochondrial function. In this study, we demonstrated that maintaining mitochondrial function is important for the protective effect of GILZ since using melanoma cell lines lacking mitochondrial activity (ρ0 cell lines) and overexpressing GILZ are susceptible to death induced by reticular stress inducers. Our studies have also shown that the increase of mitochondrial function induced by GILZ can be used to re-sensitize the cancer cells to death induced by prooxidant molecules as elesclomol.In another tumoral context, we have also demonstrated that a sub-population of BRAF mutated melanoma cells can increase mitochondrial metabolism to survive to ER stress-mediated cell death induced by several MAPK inhibitors. Resistance to MPAki involves a significant increase in mitochondrial OXPHOS associated with mitochondrial network remodeling around the ER, which facilitates mitochondrial calcium uptake. Our results have shown that mitochondrial function is crucial for the survival of cancer cells. Altogether our data indicate that given their multiple cellular roles, cancer cell mitochondria constitute attractive therapeutic targets
Algret, Romain. "Le complexe SEA : Structure et Fonction d’un Nouveau Régulateur de la Voie TORC1." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA11T006.
Full textThe TORC1 pathway plays a major role in controlling cell growth and response to various stresses. Deregulation of this pathway is found in many cancers and other diseases. In my thesis, I have shown that the SEA complex emerges as a central regulator of the various activities of TORC1. During the nitrogen deficiency, deletions of SEA complex genes in the model organism S.cerevisiae lead to the relocation of Tor1 kinase to the cytoplasm, to defects in autophagy and the fragmentation of the vacuole. Inactivation of TORC1 by treatment with rapamycin or nitrogen starvation changes the level of expression of SEA complex members. Moreover, the SEA complex interacts with mitochondrion, plays a role in oxidative stress response and can serve as a molecular link between mitochondrial functions and TORC1 pathway. Finally, I observed that the SEA complex is involved in the mechanisms of resistance to a drug often used in chemotherapy, the doxorubicin. I present in my work the first interconnectivity map protein of the SEA complex component. Our data suggest that the SEA complex emerges as a platform that can coordinate structural and enzymatic activities necessary for the efficient function of the TORC1 signalling pathway
Ibrahim, Noha. "Physiological mechanisms underlying DNA import into mitochondria and prospects for mitochondrial transfection." Université Louis Pasteur (Strasbourg) (1971-2008), 2008. http://www.theses.fr/2008STR13051.
Full textThere are considerable gaps in the understanding of the mitochondrial genetic systems and dysfunctions related to mutations in the mitochondrial DNA cannot be complemented. This is mainly due to the fact that conventional transformation of mitochondria has been unsuccessful for plants and mammals and is currently possible only for the yeast Saccharomyces cerevisiae and the green alga Chlamydomonas reinhardtii. No gene therapy strategy has thus been developed for genetic diseases due to mitochondrial DNA mutations. However, in collaboration with the groups of Y. Konstantinov (Irkutsk, Russia) and R. N. Lightowlers (Newcastle, UK), our laboratory has shown that isolated plant [1], mammalian [2] and yeast mitochondria have a natural potential to incorporate, repair and express foreign DNA. To understand, optimize and potentially use this process for mitochondrial transfection in vivo, I studied the import mechanism through biochemical, physiological and proteomic approaches. Some genetic analyses using yeast mutants were run in parallel in our laboratory. The voltage-dependent anion channel (VDAC) was identified as the putative translocator through the outer membrane. In the case of plant mitochondria, DNA import seems to follow nucleotide transport pathways to cross the inner membrane and to be concomitant with phosphate uptake and proton exchange. Nucleotide carriers also seem to play a role in DNA translocation into yeast organelles. Effectors and inhibitors have a limited effect on DNA transport into mammalian mitochondria, so that it is still difficult to figure out how the DNA crosses the inner membrane in this case. To directly identify the import complex, we designed DNA substrates with a bulky end which get stuck in the membranes during translocation. Using this system, we proved that mitochondrial protein import is not influenced when the DNA import channel is blocked, indicating that the two pathways do not overlap. On the contrary, it seems that DNA import might have some step(s) in common with another natural mitochondrial transport process: the import of cytosolic transfer RNAs (tRNAs) which compensates for the lack of a number of tRNA genes in plant organelle genomes [3]. To further characterise DNA translocation through the outer membrane and look for putative "receptors", we have analysed cyanine labeling of intact plant mitochondria in DNA import conditions. Proteins masked by the DNA were subsequently identified by mass spectrometry. However, cyanines turned out to be able to cross the outer membrane and label proteins accessible in the intermembrane space. Differential labeling nevertheless highlighted again the VDAC isoforms and two potential "receptor" candidates: the precursor of the ATP synthase beta subunit, which is present on the outer membrane, and a complex I subunit of unknown function. Mitochondrial transformation will need the maintenance of the imported DNA in the organelles. We showed that uracil-containing DNA imported into plant mitochondria can be specifically repaired in organello through a base excision repair mechanism. The first step in such a pathway is carried out by a DNA glycosylase. Through in vivo and in vitro assays, we demonstrated that uracil DNA glycosylase and 8-oxo guanine DNA glycosylase are indeed targeted to mitochondria in plants. A "rolling circle" replication pathway is likely to exist in plant mitochondria and might enable to maintain a properly designed DNA sequence upon import. However, this will require circular DNA, whereas only linear DNA is a substrate for import. We have thus analysed the in organello circularization of a linear DNA imported into plant mitochondria. Concerning the in vivo relevance of the DNA import process, we have hypothesized that it might be the basis for paternal transmission of an 11. 6 kb mitochondrial plasmid in Brassica napus [4]. We showed that this plasmid is indeed efficiently imported into isolated Brassica mitochondria. The import efficiency is due to the inverted repeats present at the ends of the plasmid and these sequences will be included in custom substrates for in vivo assays. To progress towards mitochondrial transformation in vivo, we started a new approach using DQAsomes as potential intracellular vehicles [5]. These vesicles have the property of binding DNA. They can cross the plasma membrane of mammalian cells and subsequently show a mitochondrial tropism. When contacting mitochondria, they release their DNA cargo [5], which we expect then to be imported into the organellles through the mechanism that we have studied in vitro. So far, my experiments show that DNA presented to isolated plant mitochondria by DQAsomes is imported. In vivo mitochondrial transfection assays will now be developed on this basis in plant and human cells using reporter constructs
Cailloce, Justine. "Identification des facteurs de reconnaissance des mitochondries spermatiques dans l’embryon de C. elegans, garants de l’hérédité mitochondriale uni-parentale maternelle." Electronic Thesis or Diss., Sorbonne université, 2023. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2023SORUS497.pdf.
Full textMitochondria are essential cellular components, found in the cytoplasm of the vast majority of cells in eukaryotic organisms. They are involved in a number of mechanisms that ensure proper cell function, such as apoptosis and calcium storage. The main mitochondrial function is carried out by the inner mitochondrial membrane, where protein complexes are located, enabling the production of adenosine triphosphate or ATP, the energy source for our cells. In the animal kingdom, mitochondria are the only organelles other than the nucleus to possess a genome, the mitochondrial DNA or mtDNA. The 37 genes carried by this mitochondrial genome represent only a small proportion of a cell's genes, but they are vital nevertheless. Indeed, all the proteins encoded by the mitochondrial genome are required for energy production. Therefore, disturbances in mitochondria composition and function, caused by various mutations, have been shown to be deleterious and the source of many pathologies with a wide range of symptoms.During my thesis, I focused on an atypical aspect of these organelles: their mode of inheritance. Indeed, while nuclear DNA is inherited in equal parts from each parent, the mitochondrial DNA is inherited exclusively from the mother. This particular mode of inheritance is known as maternal uni-parental mitochondrial transmission. This event of sexual reproduction is highly conserved throughout evolution, suggesting its major interest for different animal and plant species, even though some exceptions exist. This maternal uniparental inheritance results from the active degradation by an autophagy dependent mechanism, of paternal mitochondria, which enter the oocyte cytoplasm during fertilization. However, the reasons for this mode of inheritance and the mechanisms regulating it are not fully understood. For my research, I used the model organism C. elegans, which also exhibits maternal uni-parental mitochondrial inheritance. Taking advantage of the experimental advantages of this model system, my particular aim was to identify the markers carried by sperm mitochondria which trigger their recognition in the oocyte. As a first step, using imaging and a candidate gene approach, I assessed the role of poly-ubiquitylation marks in the targeting of sperm mitochondria in the embryo. The lack of a clear role for poly-ubiquitylation led me to develop a comprehensive and unbiased proteomic approach to identify mitochondrial recognition factors. This method of indirect proximity labeling by biotinylation enabled me to identify in the early C. elegans embryo, the interactome of a major protein controlling the autophagy machinery. From this interactome, I then drew up a list of candidate proteins that could act as degradation signals for the degradation of sperm mitochondria in the early embryo of C. elegans. Finally, I took part in the team's common work to establish a model of biparental heredity. To this end, we are combining all existing mutants known to act in the sperm mitochondria degradation, as well as in somatic mitophagy processes. Establishing such a genotype highlights the complexity of the mechanisms involved in uniparental inheritance, some of which remain to be elucidated
Goron, Arthur. "Propriétés nutritionnelles de la citrulline : un nouvel acteur dans la régulation du métabolisme protéino-énergétique." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAV016/document.
Full textBesides his role in the metabolism of the urea cycle, citrulline has many properties including the ability to stimulate muscle protein synthesis. However, protein synthesis is an important item of cell energy expenditure. Our work has explored both the in vivo and in vitro effects of citrulline on energy metabolism in order to understand how the activation of muscle protein synthesis by this amino acid is coordinated with energy metabolism. Our results have shown that citrulline modulates energy metabolism via a reorientation of energy flux in favor of protein synthesis. Moreover, our work has clarified citrulline effects on protein metabolism with a synergistic effect of citrulline and exercise on protein synthesis and performance. Finally, this work allowed to explore for the first time citrulline (and leucine) effects on muscle secretome. We have thus demonstrated that citrulline modulates muscle secretome and highlighted how complex is the regulation of secreted proteins by amino acids. In conclusion, our work contributes to a better understanding on muscle regulation of protein-energy metabolism by citrulline
Schubert, Susanne, Sandra Heller, Birgit Löffler, Ingo Schäfer, Martina Seibel, Gaetano Villani, and Peter Seibel. "Generation of rho zero cells." Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-167888.
Full textFaccenda, Danilo. "The role of the ATPase inhibitory factor 1 (IF1) in the regulation of apoptotic cell death." Thesis, Royal Veterinary College (University of London), 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.701678.
Full textKollberg, Gittan. "Crisis in energy metabolism : mitochondrial defects and a new disease entity /." Göteborg : Department of Pathology, Institute of Biomedicine, The Sahlgrenska Academy at Göteborg University, 2007. http://hdl.handle.net/2077/779.
Full textLu, Ming. "Cardiac Energetics in the Isolated Heart by NMR Spectroscopy and Mathematical Modeling." Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1270221813.
Full textWertzler, Kelsey Janel. "High mobility group A1 and mitochondrial transcription factor A compete for binding to mitochondrial DNA." Pullman, Wash. : Washington State University, 2009. http://www.dissertations.wsu.edu/Thesis/Summer2009/k_wertzler_051409.pdf.
Full textTitle from PDF title page (viewed on July 21, 2009). "School of Molecular Biosciences." Includes bibliographical references.
Baratli, Yosra. "Etude de la toxicité des nanoparticules d'oxyde de fer (Fe3O4) chez le rat : analyses mitochondriales et du stress oxydant." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAJ023/document.
Full textThe objective of our work is to characterize iron oxide nanoparticles (Fe3O4) and study their acute toxicity in Wistar rats. Our results showed that acute oral administration of Fe3O4, results in a dose and time-dependent alteration of oxidative stress parameters as well as liver damage. Regarding the in vitro study on isolated mitochondria, our results showed that these nanoparticles do not adversely affect the various complexes of the mitochondrial respiratory chain or mitochondrial coupling in any of the organs studied (brain, heart, lung, liverand kidneys) and regardless of the concentration used (100, 200, 300 and 500 μg/ml) while the isolated liver mitochondria from aged rats (18 months), an alteration is observed at all the complexes of the liver mitochondrial respiratory chain as well as the mitochondrial coupling regardless of the concentration used (250, 300 and 350 μg/ml), whereas for the young rats (3 months) no change is observed
Villedieu, Camille. "Rôle de la SIRT3 et de la déacétylation des protéines mitochondriales dans la cardioprotection : effet du vieillissement." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1017/document.
Full textMyocardial infarction is one of the leading causes of global mortality and improved management and reperfusion techniques have improved patient survival. Cardioprotection methods have been developed to limit the infarct size after ischemia reperfusion episode in order to limit the deleterious effects of myocardial infarction, such as ventricular remodeling and heart failure.In our study, we focused particularly on the major role of mitochondria in cell death phenomena associated with ischemia reperfusion. Within the mitochondria, our main target was sirtuin 3 (SIRT3), whose associated post-translational modifications have been shown to have a potential role in modulating ischemia-related reperfusion cell death. Thus, in the first part of our work, we were able to highlight (1) the need for SIRT3 in cardioprotection mechanisms in young mice and (2) the importance of SIRT3 deacetylation of cyclophilin D (CypD) in the success of cardioprotection.Recently, numerous preclinical studies have highlighted new techniques of effective cardioprotection in different animal models, which have not yet proved their worth after transposition in clinical study. In a second part of our work, we have endeavored to understand one of the reasons for these different clinical failures, based on the simple observation that preclinical studies are carried out on young animals, while myocardial infarction is a pathology of senescent people. We studied the impact of aging on various cardioprotection methods used in the laboratory, and demonstrated (3) mitochondrial changes impacting the deacetylation of CypD in response to cardioprotection techniques in aged mice. This study allowed us to raise a major problem of preclinical studies, namely the age of animal models used in relation to the pathology studied.This work has thus made it possible to determine the crucial role of deacetylation of CypD and SIRT3 in cardioprotection, but also to raise the question of the age of animal models before possible transfer of therapeutic advances in human clinical practice
Paradis, Stephanie. "Effet cardioprotecteur des ligands de la protéine translocatrice mitochondriale (TSPO) au cours de l'ischémie-reperfusion myocardique expérimentale : rôle du cholestérol." Thesis, Paris Est, 2012. http://www.theses.fr/2012PEST0071.
Full textIn the present work we showed that a new TSPO ligand, TRO40303, has cardioprotective properties confirming that TSPO plays a key role in the deleterious effects of myocardial ischemia-reperfusion. Similar effects have been observed with other TSPO ligands, such as 4'-chlorodiazepam, but the mechanism of action of these molecules is not known. We showed that ischemia-reperfusion in rats increased mitochondrial concentration of cholesterol, oxysterol formation and oxidative stress. 4'-Chlorodiazepam inhibited these effects and improved post-ischemic mitochondrial functions, revealing that TSPO is responsible for cholesterol transport in cardiac mitochondria and that cholesterol, in oxidized or non-oxidized forms, could participate in the deleterious effects of reperfusion. The limitation of the increase in cholesterol in mitochondria during ischemia-reperfusion is an original mechanism which could contribute to the cardioprotective effect of TSPO ligands. We then showed, in genetically modified rats with hypercholesterolemia, obesity and type II diabetes, that the concentration of mitochondrial cholesterol is very high with or without ischemia-reperfusion. We further demonstrated that 4'-chlorodiazepam has no effect on mitochondrial cholesterol after ischemia-reperfusion. These results suggest that the mechanisms of action of TSPO ligands probably differ in these conditions and that treatment must be adapted in accordance with the presence of factors of co-morbidity
Monge, Claire. "Bioénergétique systémique moléculaire dans les cellules nerveuses et musculaires : compartimentation et hétérogénéité de la diffusion de l'ATP, Interactosome Mitochondrial." Grenoble 1, 2009. http://www.theses.fr/2009GRE10312.
Full textMolecular Systems Bioenergetics is a new direction of scientific research, an important part of System Biology. It studies and describes not only the integrated energy metabolism of cells as reaction networks but also its spatial (organization) and temporal (dynamics) aspects. Molecular System Bioenergetics considers intracellular spatial organization as a dynamic, whose topology also carries information. This project aspired to emphasize an experimental approach to deal with the cellular phosphotransfer networks. The main objective of this work was the comparative description of heterogeneous compartmentation of adenine nucleotides and the complex intracellular structural and functional communications of mitochondria with other cellular structures or processes (cytoskeleton, glycolysis) in brain (synaptosomes) and cardiac cells (cardiomyocytes and cancerous HL-1 cells). Our results highlight 1/ the regulation of mitochondrial outer membrane permeability by the factor X (heterodimeric tubulin by association with the voltage dependent anion channel), 2/ the functional coupling between mitochondrial creatine kinase and adenine nucleotide translocase 3/ the mechanisms of respiration regulation in vivo and allowed the establishment of the Mitochondrial Interactosome theory, 4/ the changes in metabolism regulation in cancer cells and 5/ the heterogeneity of diffusion of adenine nucleotides and their micro- even nano-compartmentation after activation of creatine kinases (by Fluorescence Correlation Spectroscopy)
De, Vecchis Dario. "Gaining insights into mitochondrial membrane fusion through a structural and dynamic atomistic model of the mitofusin Fzo1p." Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCC001.
Full textMitochondria are dynamic organelles whose morphology is determined by fusion and fission of their membranes. This essential process is known as mitochondrial dynamics. Defects in mitochondrial dynamics are associated with neurological disorders making the investigation of physiological relevance. However, the precise sequence of events that lead mitochondrial dynamics are still not well characterised. Fzo1p, a large GTPase of the Dynamin-Related Proteins superfamily, is a key component in mitochondrial outer membrane fusion in yeast. During this PhD project I built a model of the protein Fzo1p. The structure and dynamics of the model was investigated through molecular modelling and all-atom molecular dynamics simulation in a fully hydrated lipid bilayer environment. The Fzo1p structural model integrates information from several template structures, experimental knowledge, as well as ab initio models of the transmembrane segments. The model is validated experimentally through directed mutagenesis, for instance charge-swap mutations confirm predicted long-distance salt bridges. A series of mutants indicate that coiled-coil domains are required for protein function at variance with its N-terminal region. Overall, the experimental and in silico approaches pinpoint the hinge domains involved in the putative conformational change and identifies critical residues affecting protein stability. Finally, key Fzo1p-GDP interactions provide insights about the molecular mechanism of membrane fusion catalysis. The model provides insight on atomic level and proposes a structure that will be instructional to understanding mitochondrial membrane fusion
Teixeira, Geoffrey. "Régulation du pore de transition de perméabilité mitochondriale dans la cardioprotection : interactions entre la cyclophiline D, le complexe I et le calcium." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10238.
Full textReperfusion of the heart after an ischemic event leads to the opening of a nonspecific pore in the inner mitochondrial membrane, the mitochondrial permeability transition pore (mPTP). Inhibition of mPTP opening is an effective strategy to prevent cardiomyocyte death. For example, inhibition of mPTP opening via ischaemic preconditioning (PreC) and post-conditioning (PostC) decreased the myocardial infarct size after ischemia–reperfusion. Although the molecular composition of the mPTP remains unclear, the matrix protein cyclophilin-D (CypD) is the best defined regulatory component of mPTP. In this thesis, we demonstrated that Complex I of the respiratory mitochondrial chain also regulates mPTP in a CypD-dependent manner. We also proved that inhibition of Complex I by isoflurane prevents lethal reperfusion injury in an in vivo rat model of ischemia-reperfusion. Finally, we proved that cardioprotective inhibition of CypD modulates calcium homeostasis and fluxes between mitochondria and sarcoplasmic reticulum. In summary, our results suggest that mPTP is regulated by several interconnected factors like calcium, CypD, complex I and mitochondrial functions