Dissertationen zum Thema „Maladies mitochondriale“
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Legros, Frédéric. „Étude de la dynamique du compartiment mitochondrial et des mutations hétéroplasmiques de l'ADN mitochondrial“. Paris 7, 2002. http://www.theses.fr/2002PA077109.
Der volle Inhalt der QuelleBerg, Alonso Laetitia. „Déficits de la chaîne respiratoire mitochondriale avec instabilité de l’ADN mitochondrial : identification de nouveaux gènes et mécanismes“. Thesis, Université Côte d'Azur (ComUE), 2016. http://www.theses.fr/2016AZUR4101/document.
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Berg, Alonso Laetitia. „Déficits de la chaîne respiratoire mitochondriale avec instabilité de l’ADN mitochondrial : identification de nouveaux gènes et mécanismes“. Electronic Thesis or Diss., Université Côte d'Azur (ComUE), 2016. http://www.theses.fr/2016AZUR4101.
Der volle Inhalt der QuelleNon communiqué
Aure, Karine. „Physiopathologie moléculaire et cellulaire des maladies mitochondriales à présentation neurologique“. Paris 6, 2007. http://www.theses.fr/2007PA066281.
Der volle Inhalt der QuelleBeinat, Marine. „Caractérisation génétique des atteintes hépatiques mitochondriales“. Thesis, Paris 5, 2013. http://www.theses.fr/2013PA05T007/document.
Der volle Inhalt der QuelleGenetic characterization of mitochondrial liver damage
Damiano, Maria. „Rôle de la dysfonction mitochondriale dans deux maladies neurodégénératives, la Maladie de Huntington et la Maladie de Parkinson“. Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066584/document.
Der volle Inhalt der QuelleMitochondrial dysfunction has been implicated in several neurodegenerative diseases and is correlated with augmented levels of intracellular oxydant stress. The mitochondrial defects observed in tissues from patients, as well as in animal and cellular models of Huntington’s and Parkinson’s diseases, suggest the implication of mitochondria in the pathogenesis of these diseases. The two projects discussed in this manuscript focus on the role of particular aspects of mitochondrial physiology in these diseases. By the first project we show the role of defective mitochondrial respiratory chain compex II in several rodent models of Huntington’s disease. By using a lentivirus-based gene transfert strategy we highlight the neuroprotective potential of the striatal overexpression of the subunits of complex II. The second project focus on Parkin and PINK1, two proteins implicated in the autosomal recessive, hereditary forms of Parkinson’s disease and in mitochondrial quality control mechanisms, such as mitophagy. In a cellular model we show that the two proteins facilitate Drp1-dependent mitochondrial fission. We show that Parkin may facilitate the signaling pathways controlling the activity of the pro-fission protein Drp1. This effect is probably indirect and mostly PINK1-independent. On the contrary, in mitochondrial depolarization conditions, by FRET (Förster Resonance Energy Transfer) a direct spatial coordination of Parkin, PINK1 and Drp1 is observed, which seems to be determinant for the efficiency of mitophagy. My projects shed new light on pathogenic mechanisms and open new perspectives in the research on these diseases
Rouzier, Cécile. „Déficits de la chaîne respiratoire mitochondriale avec instabilité de l'ADN mitochondrial : identification de nouveaux gènes et mécanismes“. Nice, 2012. http://www.theses.fr/2012NICE4066.
Der volle Inhalt der QuelleLefevre, Sophie. „Modèle levure de l'ataxie de Friedreich : stress oxydant, apoptose et dynamique mitochondriale“. Paris 6, 2010. http://www.theses.fr/2010PA066204.
Der volle Inhalt der QuelleGilleron, Mylène. „Complexité des maladies mitochondriales : à partir de deux exemples“. Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066136/document.
Der volle Inhalt der QuelleMitochondrial diseases represent a very diverse set of pathologies. With this work, I approached their complexity in two different situations: phenotypic analysis of fibroblasts derived from patients with defects of the respiratory complex III and phenotypic analysis of a cohort of patients, the POLG gene of whom had been sequenced. The complex III plays a central role in the mitochondrial respiratory chain. Contrary to its complete biochemical characterization, its physiological role has been relatively poorly established. We selected 15 patients with complex III defect in liver and/or muscle and with fibroblasts expressing a respiratory defect. The genetic origin was initially known for four of these defects (UQCRB, BCS1L x2, MT- CYB) and during this project, we were able to identify three additional cases (CYC1, MT- CYB, LYRM7). We sought to assess the existence of a link between the disease phenotype and the defect characteristics: gene involved, tissue expression and cellular responses. Our population of fibroblasts, genetically heterogeneous, turned also to be diverse with respect to the biochemical and cellular consequences of the defect. A "typical" profile of complex III defect therefore does not seem to exist. Pathologies related to POLG mutations are often considered the most common mitochondrial diseases in adults. Their clinical presentation is very diverse. We have investigated the specificity and sensitivity of different clinical and biological signs considered as suggestive for POLG mutations and therefore leading to POLG sequencing. To that purpose, we retrospectively analyzed the clinical phenotype and mitochondrial investigations in 154 patients for which POLG had been sequenced revealing mutations affecting two alleles of the gene in 34 patients, one allele for 10 patients and a normal sequence for 110 patients. This study has shown that POLG mutations were responsible of recurrent clinical and paraclinical signs, whose sensitivity and specificity when considered in association allowed to propose a diagnostic flowchart for POLG sequencing. This study has also permitted to establish the natural story of diseases associated with deleterious POLG mutations in adults. In conclusion, classification of mitochondrial diseases by a common biochemical abnormality, a complex III defect in the present case, leads to group very different diseases that differ from their clinical, biochemical and cellular patterns. On the contrary, even in diseases considered highly diverse as those due to POLG mutations, classification by the affected gene allows to identify recurrent presentations in a population of adult patients with neurological presentation
Kelly-Aubert, Mairead. „Anomalies de la balance redox mitochondriale dans la mucoviscidose“. Paris 6, 2011. http://www.theses.fr/2011PA066027.
Der volle Inhalt der QuelleSayadi, Kéfi. „Myopathie mitochondriale : discussion d'une observation avec déficit des groupes II et IV de la chaîne respiratoire mitochondriale“. Montpellier 1, 1991. http://www.theses.fr/1991MON11157.
Der volle Inhalt der QuelleKhosrobakhsh, Farnoosh. „Caractérisation de Msp1, un acteur de la dynamique mitochondriale, chez la levure à fission“. Toulouse 3, 2010. http://thesesups.ups-tlse.fr/1159/.
Der volle Inhalt der QuelleMitochondrial dynamics is a regulated interplay between antagonistic fission and fusion forces acting on mitochondrial membranes. This process determines mitochondrial morphology; when fission or fusion predominates, mitochondria appear as isolated dots or as a filamentous and interconnected network, respectively. Proteins that control the morphology of mitochondria have been identified. Our team has isolated and characterized Msp1p in the fission yeast Schizosaccharomyces pombe, and its human orthologue OPA1, which control mitochondrial fusion. Furthermore we have found that mutations in the OPA1 gene are associated with the most frequent form of autosomal dominant optic atrophy that features a progressive loss of retinal ganglion cells, often leading to blindness. Understanding the function of the dynamin Msp1p requires identification of its partners, which was part of my thesis. To perform a genetic screen for msp1+ interactors, I generated a thermosensitive (ts) mutant of msp1+ (Msp1P300S) by homology to a ts substitution described at a position conserved in other dynamins. The mutation was integrated at the msp1+ locus by homologous recombination. I then characterized this mutant to search for conditions of lethality. At restrictive temperature, the mutant had fragmented mitochondria when grown on respiratory, glucose-containing medium, and further showed altered respiration and increased ROS production on non-fermentable ethanol/glycerol-containing medium. Perturbation of colony pigmentation in ade6 background, which relates to mitochondrial dysfunctions, and lethality on non-fermentable galactose-containing media, were also observed. As a perspective, we plan to take advantage of this latter property to screen a cDNA library for the presence of multicopy suppressors of thermolethality. In addition to this work, we have studied the mechanisms of maturation of Msp1p, which is processed into a long and a short isoform (l- and s-Msp1p) during its biogenesis. Using mutants of various mitochondrial proteases, we demonstrated that the two isoforms of Msp1p are independently formed from the same precursor and that generation of s-Msp1p implicates Rhomboid 1. Furthermore, we showed that the m-AAA protease Paraplegin might control the stability of l-Msp1p. These proteases mutants were also used to study the proteolysis of the eight OPA1 splicing variants heterologously expressed in S. Pombe. Most of these variants were only processed by Paraplegin, a finding that could allow to precise contradictory results obtained in mammals where Yme1p and Rhomboid 1 were implicated in the maturation of OPA1. Together, my thesis works will allow to better understand the mode of action of Msp1 in mitochondrial functions and to identify new actors and regulators of mitochondrial dynamics possibly implicated in orphan mitochondrial pathologies
Sternberg, Damien. „Contribution à trois aspects de la génétique mitochondriale humaine : étude de transmission de l'ADN mitochondrial lors de fécondations in vitro - caractérisation de mutations de l'ADN mitochondrial dans les maladies mitochondriales et le vieillissement musculaire“. Paris 12, 2002. http://www.theses.fr/2002PA120010.
Der volle Inhalt der QuelleMitochondrial genetics is important to consider when dealing with infertility, mitochondrial diseases or ageing. Our work contributes to the clarification of the role and behaviour of mitochondrial DNA (mtDNA) in those three circumstances. First, we studied mtDNA inheritance in children born after a particular in vitro fertilisation technique, i. E. Intracytoplasmic injection of spermatozoon (ICSI). Although the risk of transmission of a paternal infertility-linked nuclear defect by this technique is well known, the possible transmission of the patemal mtDNA had never been addressed by means of highly sensitive detection assays. By using different sensitive techniques, we showed that there was no detectable paternally inherited mtDNA in the peripheral blood of the 27 children who were studied. Second, we aimed at determining the contribution of mtDNA tranfer RNA (tRNA) gene defects to the pathogenesis ofmitochondrial disorders. We set up an exhaustive scanning method to screen ah tRNA genes for mutations, and applied it to a large number of selected patients with mitochondrial disorders. We found numerous sequence variations of those genes, some of them already known to be pathogenic or polymorphie, others being questionable from a functional point of view. We performed an evaluation of each questionable sequence variation by all possible means, and were able to assign a precise significance to most of them. In retrospect, we tried to delineate the best indications for the screening ofmtDNA tRNA genes. Third, we wanted to determine the contribution of mtDNA mutations to the ageing process of human muscle, at a single fibre level. We looked for large-scale rearrangements and tRNA gene point mutations in a large number of fibres defective in cytochrome c oxidase (COX- fibres) activity and an equal number of normal fibres (COX+ fibres) from normal biopsy samples taken from ageing subjects. We detected large scale rearrangements in several fibres. Most interestingly, we detected, characterised and quantified tRNA gene point mutations in several COX- fibres, such mutations being absent from COX+ fibres. We showed that clonally expanded point mutations contribute toageing process in muscle, by a segmental alteration of the respiratory chain activity
Favory, Raphaël. „Syndrome de Détresse Microcirculatoire et Mitochondriale dans le sepsis“. Phd thesis, Université du Droit et de la Santé - Lille II, 2007. http://tel.archives-ouvertes.fr/tel-00476831.
Der volle Inhalt der QuelleBenard, Giovanni. „Etude de l'expression de défauts d'activité de la chaîne respiratoire mitochondriale : analyse des mécanismes de compensation au niveau de la mitochondrie et de la cellule“. Bordeaux 2, 2006. http://www.theses.fr/2006BOR21365.
Der volle Inhalt der QuelleThis work concerns the study of mitochondrial oxidative phosphorylation, and the repercussion of respiratory chain activity defects on (i) mitochondrial energy fluxes, (ii) mitochondrial network organization, and (iii) mitochondrial biogenesis. Firstly, we show that in response to a specific enzymatic defect, as occurs in mitochondrial diseases, the flux of oxidative phosphorylation is maintained constant by compensatory adjustments of the redox state of cytochrome c and coenzyme Q. In living cells, the inhibition of respiratory chain activity resulted in the remodelling of mitochondrial structure and we provided a descriptive model to analyze the underlying metabolic signals. Lastly, we observed the accumulation of mitochondria, in the muscle of patients carrying a severe defect. This phenomenon of mitochondrial biogenesis induction was dependent on intracellular nitric oxide production. Taken together, these results describe the sequential expression of a respiratory chain activity defect, and evidence a series of addtive mechanisms of compensation that could play a role in mitochondrial physiopathology
Bertholet, Ambre. „Influence de la protéine de fusion mitochondriale OPA1 sur le métabolisme oxydatif neuronal et la transmission synaptique“. Toulouse 3, 2011. http://thesesups.ups-tlse.fr/2180/.
Der volle Inhalt der QuelleIn the past few years, multiple findings have suggested that disruptions of mitochondrial functions and dynamics contribute to neurodegenerative diseases. Mitochondrial functions in neurons include regulation of calcium and redox signaling, developmental and synaptic plasticity as well as the arbitration of cell survival and death. Mitochondrial dynamics controls the organelle's morphology via a delicate balance of two opposing forces: mitochondrial fusion and fission that are regulated by large dynamin-related GTPases evolutionary conserved from yeast to human. We have previously demonstrated that the fusion protein OPA1 loss or mutations led to mitochondrial inner membrane dysfunctions and apoptosis of particular importance in optic nerve pathologies like ADOA1 (autosomal dominant optic atrophy). While links emerge between defects in mitochondrial fusion and neurodegeneration, the processes involved are still largely unknown. To understand the mechanisms by which alterations of mitochondrial dynamics could contribute to mitochondria dysfunction, eventually leading to neurodegeneration, we studied the effects of OPA1 loss of function in neurons ex vivo. In cortical neurons, RNA interference of the fusion protein OPA1 led to mitochondrial fragmentation without altering neither mitochondrial distribution nor neuronal death rate. While there was no incidence on dendrites and axon size and numbers, the quantity of several synaptic proteins was reduced, suggesting synaptic impairment. In these conditions, the redox state of OPA1 depleted-neurons was impaired and specific respiratory complex proteins quantities were decreased. Finally, electrophysiological recordings showed that OPA1 depletion induced changes in synaptic transmission, particularly in decreasing of EPSC frequency and by increasing IPSC frequency. Interestingly, forskolin treatment rescue these electrophysiological defaults. In conclusion, our data may offer new insights not only into mitochondrial dynamics-linked neurodegenerative diseases like ADOA1 but to other neurodegenerative pathologies correlated with oxidative metabolism such as Huntington's, Parkinson's and Alzheimer's diseases
Bris, Céline. „Influence de la génétique mitochondriale en pathologie : apport des techniques de séquençage haut débit Deep sequencing shows that oocytes are not prone to accumulate mtDNA heteroplasmic mutations during ovarian ageing Novel NDUFS4 gene mutation in an atypical late-onset mitochondrial form of multifocal dystonia“. Thesis, Angers, 2017. http://www.theses.fr/2017ANGE0093.
Der volle Inhalt der QuelleMitochondrial diseases are common metabolic disorders characterized by strong clinical and genetic heterogeneity, in particular due to the dependence on 2 genomes, nuclear (nDNA) and mitochondrial DNA (mtDNA), and the concept of mitochondrial heteroplasmy. The purpose of this work was to develop a strategy for the analysis of the mtDNA through next-generation sequencing (NGS), and then to apply it to the study of mitochondrial diseases and those related to aging: primary open-angle glaucoma (POAG) and ovarian aging. After validating the performances of our NGS strategy for the detection and quantification of mtDNA variations, we confirmed the power of systematic analysis of the whole mitochondrial genome with the use of uroepithelial cells for mitochondrial diseases diagnosis and the identification of novel mtDNA variants. However, these advances generate new challenges such as the interpretation of low percentages of mtDNA mutations or the prediction of the pathogenicity of new variants. For aging-related diseases, we have identified the possible protective role of the mitochondrial haplogroups T and H in women, respectively in the occurrence and severity of POAG, suggesting that mtDNA influence is drivenby gender, and thus the importance of gender stratification for association studies. By contrast, we did not observe any accumulation of mtDNA abnormalities in early ovarian aging. In perspective, we report the identification of a nDNA mutation in an atypical phenotype, highlighting the complexity of mitochondrial diseases diagnosis, due to this double genome
Baris, Olivier. „Tumeurs oncocytaires thyroïdiennes : étude des mécanismes responsables de la prolifération mitochondriale par analyse transcriptomique“. Angers, 2004. http://www.theses.fr/2004ANGE0511.
Der volle Inhalt der QuelleThyroid oncocytomas are tumours made up of cells with abundant, granulous and eosinophilic cytoplasm. This phenotype is caused by an important mitochondrial accumulation of unknown origin. These tumours represent a diagnostic dilemma because the traditional criteria of malignancy do not always allow the distinction between benign and malignant tumours. We explored the transcriptional profiles of these tumours in a global way (microarrays, differential display) and a targeted way (RT-PCR) in order to identify the mechanisms responsible for the mitochondrial proliferation and to discover genes likely to help in the diagnosis of malignancy. Our results show a global increase in mitochondrial biogenesis in these tumours. Oxidative metabolism seems to characterise thyroid oncocytomas and probably plays a central role in their development. Lastly, our work supports the assumption of a continuous evolution between oncocytic adenoma and carcinoma
Sutton, Angela. „Dimorphisme génétique de la superoxyde dismutase à manganèse : rôle dans la toxicité mitochondriale de l'alcool“. Paris 5, 2003. http://www.theses.fr/2003PA05N088.
Der volle Inhalt der QuelleOnly some subjects develop severe alcoholic diseases after chronic alcohol abuse, suggesting risk factors existence. Manganese superoxide dismutase (MnSOD) detoxifies superoxide anion into hydrogen peroxide, is inducible by alcohol, and is imported post-translationaly into mitochondria with a targeting sequence. A genetic dimorphism modifies one amino acid and the presequence structure: α helix for Ala, β sheet for Val. Ala/Ala genotype is associated with an increased risk to develop severe alcoholic liver diseases. Ala-MnSOD presequence leads to more MnSOD efficient translocation towards mitochondriale membranes into isolated mitochondria, leading to a MnSOD activity 40% higher than the Val-one.
Laudette, Marion. „Rôles et mécanismes d’action de la protéine Epac1 mitochondriale dans les pathologies cardiaques“. Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30066.
Der volle Inhalt der QuelleLe cœur est un organe énergivore dont la majorité de l’ATP consommée provient du métabolisme oxydatif de la mitochondrie. Cet organite joue également un rôle central dans la régulation de l’homéostasie calcique, la production des espèces réactives de l’oxygène (ROS) et l’apoptose. Ces fonctions sont dérégulées au cours de l’insuffisance cardiaque (IC). Il est donc important d’identifier les signalisations à l’origine de ces dysfonctions et de les valider en tant que cible thérapeutique pour le traitement de l’IC. Bien que le second messager AMP cyclique (AMPc) soit essentiel à la fonction cardiaque, il contribue à la progression de l’IC. Cependant, les bases moléculaires de ses effets délétères dans les pathologies cardiaques sont loin d'être élucidées. Le but de ce travail fût de déterminer les effets mitochondriaux d’une protéine effectrice de l’AMPc, Epac1. Nous avons étudié ses rôles mitochondriaux (mitEpac1) dans deux conditions de stress cardiaque connues pour perturber le fonctionnement de la mitochondrie : un stress aigu induit par une ischémie reperfusion (I/R) et un stress chronique provoqué par un régime riche en graisse (HFD) conduisant à une cardiomyopathie diabétique. Par ailleurs, nous avons caractérisé un nouvel inhibiteur pharmacologique de Epac1 appelé AM-001 et étudié ses propriétés cardioprotectrices chez la souris. D’une part, nous montrons que la délétion génique de Epac1 (Epac1-/-) chez la souris protège des lésions de l'I/R myocardique en réduisant la taille de l’infarctus. L'inhibition pharmacologique de Epac1 par le CE3F4 prévient de l'apoptose des cardiomyocytes (CM) induite par l'hypoxie/réoxygénation (HX+R). Sur le plan mécanistique, Epac1 est activé par l'AMPc produit par l’adénylate cyclase soluble (sAC). De plus, Epac1 est associé à un complexe macromoléculaire composé du canal calcique VDAC1, de la protéine chaperonne GRP75 et du récepteur type 1 à IP3. Epac1 favorise la formation de ce complexe dans des conditions HX+R pour induire une surcharge de Ca2+ mitochondriale et l’ouverture du pore de transition de perméabilité mitochondriale. MitEpac1 inhibe aussi l’activité de l'isocitrate déshydrogénase 2 diminuant ainsi la synthèse de NADPH et les capacités antioxydantes du CM. Dans un modèle de CMD induit par un stress métabolique (HFD), les cœurs Epac1-/- sont protégées de la dysfonction diastolique, de la fibrose et de l’accumulation de lipides. L’inhibition de Epac1 prévient des dysfonctions mitochondriales (production de ROS, mort cellulaire, accumulation lipidique, diminution du métabolisme oxydatif) induites par le palmitate, un acide gras (AG) lipotoxique. Au niveau moléculaire, cet AG régule positivement l’activité de Epac1 par la palmitoylation de sAC et favorise la production d’AMPc. Epac1 influence également le métabolisme énergétique en modulant l’activité des enzymes clefs de la β-oxydation (impliquée dans la dégradation des AG) et de l’ATP synthase (impliquée dans la production d’ATP) favorisant la lipotoxicité du palmitate. Ayant obtenu la preuve de concept des effets bénéfiques de l’inhibition de Epac1 dans les stress cardiaques, nous avons caractérisé un nouvel inhibiteur pharmacologique. Cette petite molécule appelée AM-001 est cardioprotectrice dans un modèle murin d’I/R. AM-001 protège de l'hypertrophie cardiaque, l'inflammation, la fibrose et améliore la fonction cardiaque lors de l'activation chronique des récepteurs β-adrénergiques par l’isoprénaline. Au niveau moléculaire, AM-001 inhibe l'action non canonique de GRK5 sur l’export nucléaire de HDAC5 régulant négativement le facteur de transcription prohypertrophique MEF2. En conclusion, nos résultats révèlent l'existence au sein de la mitochondrie de différents microdomaines AMPc-Epac1 qui contrôlent les fonctions mitochondriales et suggèrent que Epac1 constitue une cible prometteuse pour le traitement des lésions myocardiques induites par l'I/R ou un stress cardio-métabolique prolongé
Godard, Francois. „ATP synthase mitochondriale : fonction de la sous-unité ε et biogenèse du F0“. Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0092/document.
Der volle Inhalt der QuelleAt first, I am interested in the ε subunit of mitochondrial ATP synthase in yeast, an organism that is well suited for the study of mitochondrial functions. This protein is a part of the ATP synthase called central stalk. This allows the coupling of proton translocator domain of this enzyme (FO) to its catalytic domain (F1) where ATP is synthesized. Using a tetO expression system, I showed that in the absence of the ε subunit, F1 and FO domains are no longer coupled. It results in a massive proton leakage across the inner membrane of mitochondria. I then showed that the absence of the ε subunit can be compensated by mutations slowing the activity of FO. These data allow to conclude that the ε subunit is necessary to maintain the physical integrity of the ATP synthase for oxydative phosphorylation. Later, I tried to identify new factors involved in the biogenesis of the FO. For this, I used a genetic screen where the survival of yeast cells is conditioned by mutations inactivating the FO. About a thousand clones were analyzed. The mutations were localized in mitochondrial and nuclear genomes. Eighteen clones with mutations in genes encoding not yet known ATP synthase expression factors were completely sequenced. Several new cellular systems that are potentially involved in the biogenesis of FO were identified
Turkieh, Annie Elia. „Contribution à l'étude du rôle physiologique de l'apolipoprotéine O“. Toulouse 3, 2012. http://thesesups.ups-tlse.fr/1997/.
Der volle Inhalt der QuelleThe mitochondrial permeability transition pore (MPTP), first considered to play a key role in "life or death" decisions of the cell has been proposed to be a target for cardioprotection during heart disease. This pore enables free passage into the mitochondria for molecules and metabolites smaller than 1. 5 kDa6, including protons thus leading to mitochondrial uncoupling. The exact protein composition of the MPTP is still under debate but minimally includes cyclophilin D and adenine nucleotide translocase (ANT) which is proposed to be a regulatory component. Thus, MPTP regulators are of central importance to the control of mitochondrial (dys)function and the fate of cardiomyocytes. In this study, we demonstrate the importance of apolipoprotein O (ApoO) as a new signal regulator of the MPTP. Through a functional genomics study aimed at identifying genes differentially regulated in the heart by obesity13, we discovered a new apolipoprotein (ApoO) as overexpressed in the heart of diabetic patients. In the present study, we sought to uncover how changes in the expression of this protein relate to modifications of cardiac function. We used cardiac myoblasts, in vivo transfected mouse liver, human heart samples and cardiac specific transgenic mouse lines constitutively expressing ApoO at physiological levels. These mice, exhibited depressed ventricular function, characteristic patterns of systolic dysfunction, and dilated cardiomyopathy. We show that ApoO localizes within mitochondria and that its expression associates with mitochondrial dysfunction in mouse and human heart. ApoO interacts with ANT and causes the MPTP to adopt an open state, inducing mild uncoupling. Consequently, mitochondrial respiration and fatty acid metabolism are enhanced. This cascade of events generates a mitochondrial metabolic sink whereby cells accumulate lipids and lipotoxic byproducts leading to apoptosis, loss of cardiac myoblasts and cardiomyopathy mimicking the metabolic phenotype of the diabetic heart. We propose a model for the original molecular mechanisms that may account for the ApoO induced mitochondrial dysfunction through the MPTP opening regulation. The molecular mechanisms that initiate, mediate and trigger mitochondrial dysfunction in response to lipid overload remain unclear. Our results distinguish the interplay between mitochondrial dysfunction and lipotoxicity and demonstrate, for the first time, the implication of the permeability transition pore in lipid metabolism in mouse and human heart. ApoO-model could be an original link between impaired mitochondrial heart function and lipid accumulation. ApoO may open up novel strategies to control lipid overload in pathophysiological situation like obesity, diabetes and cardiomyopathy
Bouaita, Aïcha. „Essais de thérapie génique contre la dégénérescence rétinienne chez la souris Harlequin déficiente pour la protéine mitochondriale AIF“. Paris 6, 2012. http://www.theses.fr/2012PA066566.
Der volle Inhalt der QuelleJacoupy, Maxime. „Perte de fonction de la voie de signalisation <> dans la physiopathologie de la maladie de Parkinson - Mécanismes et conséquences“. Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066387/document.
Der volle Inhalt der QuelleParkinson’s disease (PD) is linked to a specific loss of dopaminergic neurons of the substancia nigra. The disease is most often sporadic but familial monogenic forms exist, for example due to mutations in PARK2 or PINK1. Those genes encore the cytosolic ubiquitin-protein ligase Parkin and the mitochondrial serine/threonine kinase PINK1, both essential for mitochondrial quality control. This work studies the role of their interaction at the outer mitochondrial membrane in the regulation of mitochondrial homeostasis. We found that the association of PINK1 and Parkin to the mitochondrial import TOM complex during mitochondrial stress induces the import of most proteins targeted to mitochondria; that destabilizing this complex is sufficient to initiate mitophagy; and that Parkin activation by PINK1 facilitates the import of its substrate, HSD17β10. We developed an inducible BRET-based molecular biosensor to study the classical pre-sequence import pathway. We also found, in a neuronal model, that mitochondrial stress induced a strong increase in the expression of mitochondrial biogenesis key genes, in the presence of Parkin; and that these genes are basally up-regulated in PARK2-/- neurons, possibly reflecting an alteration of acute stress response. These results increase our understanding of the pathophysiology of autosomal recessive forms of PD, underlining the importance of the PINK1/Parkin pathway in mitochondrial import and biogenesis
Mayeur, Anne. „La prévention des maladies mitochondriales par mutation de l'ADNmt : de la clinique au transfert de pronoyaux“. Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASL084.
Der volle Inhalt der QuelleMitochondria have the unique characteristic of possessing their own genome, mitochondrial DNA (mtDNA), which is exclusively transmitted by the mother through the cytoplasm of the oocyte. Pathogenic mutations in mtDNA are responsible for mitochondrial diseases. Pronuclear transfer (PNT), not authorized in France, is a technique proposed by the United Kingdom since 2016 to replace the mutated mitochondrial genome of a zygote with a non-mutated one. This method remains widely debated internationally regarding its efficacy and safety. The aim of our work was to evaluate the clinical and and technical feasibility of PNT. Our research confirmed that women carrying a pathogenic variant of mtDNA exhibited ovarian response criteria to stimulation comparable to a control group. Through a sociological study, we also showed that this technique received support from the majority of women surveyed, primarily because it maintains a genetic link between a woman and her child. Subsequently, we developed the PNT technique using triploid zygotes (3PN) donated for research, following authorization from the Biomedicine Agency. Finally, we assessed the relevance of using 3PN and demonstrated their limitations in terms of development and chromosomal status, even when diploidy was restored. This work opens up perspectives on the feasibility and acceptance of PNT. Future research is necessary to explore the safety of this technique
Belzacq, Anne-Sophie. „La voie mitochondriale de l'apoptose, identification d'une nouvelle cible thérapeutique potentielle : le translocateur de nucléotides à adénine (ANT)“. Compiègne, 2002. http://www.theses.fr/2002COMP1408.
Der volle Inhalt der QuelleBertolin, Giulia. „Elucidating the functional interplay between Parkinson’s disease-related proteins and the mitochondrion“. Thesis, Paris 5, 2013. http://www.theses.fr/2013PA05T043/document.
Der volle Inhalt der QuelleParkinson’s disease (PD) is a common neurodegenerative disorder of unknown etiology, affecting nearly 5% of the world population over the age of 80. Nearly 10% of PD cases are familial forms with Mendelian inheritance pattern. Mitochondrial dysfunction has long been suspected to play a role in the physiopathology of sporadic PD. This possibility has been recently corroborated by major discoveries in the field of autosomal recessive PD. Parkin and PINK1, the products of two genes associated with these forms, participate in a common molecular pathway focused on maintenance of mitochondrial quality, with roles in mitochondrial transport, dynamics, biogenesis and clearance.The aim of this work was to elucidate some of the molecular mechanisms underlying the regulation of mitochondrial homeostasis by Parkin and PINK1. We used a combination of approaches in molecular and cell biology, biochemistry and confocal microscopy to identify and characterize molecular interactors of Parkin and PINK1 on the outer mitochondrial membrane (OMM).In the first part of my project, we discovered that Parkin and PINK1 associate on dysfunctional mitochondria in proximity of the translocase of the OMM (TOM), a complex devoted to the mitochondrial import of the vast majority of the mitochondrial proteins. We provided evidence that these associations play a key role in activation of the mitochondrial degradation program mediated by the PINK1/Parkin pathway. We also observed that the dynamin-related GTPase Drp1, involved in mitochondrial fission is recruited to defective mitochondria in proximity of Parkin and PINK1, suggesting that mitochondrial fission occurs at sites where mitochondrial clearance is initiated.In the second part of my project, we characterized the functional interaction between Parkin and the multifunctional neuroprotective mitochondrial matrix enzyme 17B-hydroxysteroid dehydrogenase type 10 (HSD17B10), previously found by the team to be altered in abundance in Parkin-deficient mice. We demonstrated that HSD17B10 exerts a mitochondrion-protective function independent of its enzymatic activity. In addition, we provided evidence that Parkin directly interacts with HSD17B10 at the TOM machinery and that it positively regulates its mitochondrial levels, possibly through the regulation of its mitochondrial import.Altogether, these results provide novel insights into the molecular mechanisms by which Parkin and PINK1 control mitochondrial quality, and deepen our understanding of the role of these proteins in the physiopathology of autosomal recessive PD
Wolff, Valérie. „Physiopathologie de l’infarctus cérébral du sujet jeune : rôle de la résine de cannabis dans l’atteinte vasculaire et l’altération mitochondriale cérébrales“. Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAJ122/document.
Der volle Inhalt der QuelleWe showed that: a) there was a link between cannabis use and intracranial arterial multifocal stenosis in a series of ischemic stroke in the young, b) the prevalence of intracranial arterial stenosis was up to 31% in a series of 159 ischemic strokes in the young, c) 13% of the patients in this series sustained the angiographic criteria of reversible cerebral vasoconstriction syndrome, and that the precipitating factor was the use of cannabis in 67% of cases, d) tetrahydrocannabinol (THC, the main active component in cannabis) inhibits the respiratory mitochondrial chain of the brain in rats and induces a significant production of hydrogen peroxide. These results suggest that one of the mechanisms of brain toxicity induced by cannabis in ischemic stroke patients, may be the high rate of generation of free radicals induced by THC
Gutierrez, Cortes Nicolas. „Expression métabolique des polymorphismes mitochondriaux : mutations pathogènes et haplogroupes“. Thesis, Bordeaux 2, 2011. http://www.theses.fr/2011BOR21877/document.
Der volle Inhalt der QuelleMitochondria, 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
Mammeri, Hélène. „Déficit en complexe I de la chaîne respiratoire mitochondriale d'origine nucléaire“. Paris 5, 2010. http://www.theses.fr/2010PA05P631.
Der volle Inhalt der QuelleMitochondrial complex I (or NADH-ubiquinone oxidoreductase) includes 38 nuclear subunits and 7 mitochondrial subunits. Complex I deficiency frequently accounts for mitochondrial disorders. Pathogenic mutations of complex I nuclear genes are often private. Moreover, the genotype – phenotype correlation is inconstant in the rare recurrent mutations. Identification of all mutations responsible for complex I deficiency is challenging but essential for providing accurate and helpful genetic counselling. An isolated complex I deficiency was biochemically detected in 19 patients. We screened for complex I nuclear genes mutations using the mismatch-specific DNA endonuclease Surveyor TM. Fragments of the complementary DNA of 12 complex I nuclear genes, encoding 10 structural proteins and 2 assembly proteins, were amplified for heteroduplexe formation followed by digestion. Pathogenic mutations were identified in 3 patients. Direct sequencing was performed for 2 other assembly genes, characterized by frequent polymorphisms or presence of several alternative transcripts. An abnormal complex I expression was detected by Blue Native electrophoresis followed by Western Blot in the studied patients. The Surveyor TM digestion – based method was efficient for limiting the number of sequence reactions. This method is useful and time – less consuming for the rapid mutation screening of a large number of genes
Conjard, Agnès. „Effets de l'insuffisance rénale et d'une myopathie mitochondriale sur les activités enzymatiques du métabolisme énergétique dans les fibres musculaires uniques humaines“. Lyon 1, 1995. http://www.theses.fr/1995LYO1T126.
Der volle Inhalt der QuelleParadis, 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.
Der volle Inhalt der QuelleIn 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
Bizat, Nicolas. „Etude des mécanismes de mort neuronale, in vivo, induits par une atteinte mitochondriale : implication pour la maladie de Huntington“. Paris 11, 2003. http://www.theses.fr/2003PA112110.
Der volle Inhalt der QuelleStriatal cell death in Huntingtan's Disease (HD) may involve mitochondrial defects, N-Methyl-D-Aspartate receptor- mediated excitotoxicity and activation of death effector proteases such as caspases and calpain. However, the precise contribution of mitochondrial defects in the activation of these proteases in HD is unknown. Here, we addressed this question by studying the mechanism of striatal cell death in rat models of HD using the mitochondrial complex II inhibitor 3-nitrapropionic acid (3NP). Caspase-9 activation preceded neurodegeneration in both cases. However, caspase-8 and -3 were activated in the acute model, but not in the chronic model, showing that 3NP does not require activation of these caspases to produce striatal degeneration. In contrast, activation of calpain was specifically detected in the striatum in both models and this was associated with a calpain-dependent cleavage of huntingtin. Finally, in the chronic model which mimicks a steady blockade of complex II activity reminiscent of HD, selective calpain inhibition prevented the abnormal calpain-dependent processing of huntingtin, reduced the size of the striatal lesions. The present results demonstrate that calpain is a predominant effector of striatal cell death associated with mitochondrial defects in vivo. Morever, the role of caspases and calpains in neurodegeneration, particulary in HD, remains unclear. Results showed that 3NP-induced death of striatal neurons was preceded by cytochrome c redistribution, transient caspase-9 processing and activation of calpain whereas, levels of the active/processed form of caspase-3 remained low and were even decreased compared to control animals. Here we showed that this decrease in active caspase-3 levels could be due to calpain activation. Several observations supported this conclusion: 1) pharmacological blockade of calpain in 3NP-treated rats increased the levels of endogenous processed caspase-9 and -3, 2) cell free extracts prepared from striatum of 3NP-treated rats degraded in vitro the p34 and p20 subunits of active recombinant caspase-9 and -3 respectively. .
El, Fissi Najla. „Caractérisation d'allèles de mitofusine associés à la maladie de Charcot-Marie-Tooth : mise en évidence de l'implication d'un déséquilibre entre fusion et fission mitochondriale dans le dysfonctionnement des neurones“. Thesis, Aix-Marseille, 2017. http://www.theses.fr/2017AIXM0250/document.
Der volle Inhalt der QuelleMitochondria form a dynamic network remodeled by two antagonistic processes called mitochondrial fusion and fission. While mitochondrial fusion creates interconnections between mitochondria, mitochondrial fission result in fragmentation. These processes are mediated by Dynamin-related GTPases, the outer-membrane fusion protein mitofusin, and the fission factor DPR1.The main aim of my resaearch was to characterize the impact of an imbalance between mitochondrial fusion and fission in neurons in the context of a severe hereditary neuropathy called Charcot-Marie-Tooth type 2A (CMT2A). Indeed, this disease is caused by dominant mutations in the mitofusinMFN2.In order to dissect the mechanisms by which these mutations alter mitofusin properties and neuronal function, we developed four drosophila models of CMT2A expressing the two most frequent substitutions (R94Q, R364W) and two others localizing to similar domains (T105M, L76P). The four alleles resulted in mitochondrial depletion at neuromuscular junctions, decreased oxidative metabolism, increased mtDNA mutations, and impaired locomotion that were associated with aberrant mitochondrial morphology. Interestingly, while GTPase domain-associated mutations (R94Q, T105M) aggregate unfused mitochondria, mutations within helix bundle 1 (R364W, L76P) unexpectedly enhance mitochondrial fusion, as demonstrated by rescue of mitochondrial morphology and locomotion provided by the DRP1 fission factor. In conclusion, we show that both dominant negative and dominant active forms of mitofusin can cause CMT2A, and propose for the first time that excessive mitochondrial fusion drives CMT2A pathogenesis in a large number of patients
Nguyen, Phuc Minh Chau. „Fusion Mitochondriale et Effets Vasculaires : rôle de OPA 1 dans l'hypertension artérielle et le vieillissement“. Thesis, Angers, 2015. http://www.theses.fr/2015ANGE0073.
Der volle Inhalt der QuelleDefects in mitochondrial dynamics have been associated with various disorders, including cardiovascular diseases. OPA1 is essential for mitochondrial inner membrane fusion. Mutation in Opa1 is associated with the autosomal dominant optic atrophy (ADOA). Since then, OPA1 has been reported to be associated with cell apoptosis, cell proliferation, mitochondrial ATP synthesis, calcium homeostasis and ROS production. These data suggest that OPA1 has a potential role in vascular cells and subsequently affects vascular function. On the other hand,OPA1 is also associated with age-related changes of mitochondria and simultaneously contribute to the development of many dysfunctions in different organs. In this study, we investigated impacts of OPA1 mutation on vascular function in physiological and pathological condition like hypertension and vascular aging. By using an Opa1+/- heterozygote mouse model, we show that the OPA1 protein plays a protective role in the vascular system. Indeed, Opa1+/- mice developed a hypertension more severe than WT mice which was associated with more important endothelial dysfunction and altered vascular remodeling. In addition, although initial vascular function was normal, at 12 months, Opa1+/- mice displayed vascular dysfunction which might predict onset of vascular diseases at a later time. These results suggest for the first time that mitochondrial dynamics might play an important role in vascular function and adaptation in pathological conditions and in vascular aging. More studies are needed to clarify the role of the protein OPA1 in hypertension. These data may help to identify novel therapeutic targets to prevent complications of hypertension and vascular age-related diseases
Castanier, Céline. „Étude de la régulation de la protéine mitochondriale MAVS au cours de l’immunité innée antivirale“. Thesis, Paris 11, 2011. http://www.theses.fr/2011PA11T046.
Der volle Inhalt der QuelleInnate Immunity acts as the first line of the host defense against viral infection, providing a rapid response to restrict the microbial threats. Toll-like receptors (TLRs) and cytosolic RIG-I-like helicases (RLRs) are the two major receptor systems for detecting virus. Viral nucleic acids are recognised by the helicases RIG-I and MDA5. These receptors contain two CARD domains involve in the recruitment of the mitochondrial antiviral signaling adaptor MAVS whose activation triggers a rapid production of type 1 interferons (IFNs) and of pro-inflammatory cytokines. Interestingly, it has been reported that MAVS must be localized to mitochondria to exert its function. While MAVS is essential for this signaling, its function and regulation remain unclear. In this work, we report that RLR activation triggers MAVS ubiquitination by the E3 ubiquitin ligase TRIM25 and marks it for proteasomal degradation concomitantly with downstream signaling. MAVS appears to function as a recruitment platform to first assemble a signaling complex, then the proteasome-mediated MAVS degradation is required to unleash into the cytosol this signaling complex allowing the signalosome activation and ensuing type I IFNs production. Futhermore, we reported that mitochondrial dynamics regulate MAVS-mediated signaling after viral infection
Procaccio, Vincent. „Caractérisation des gènes des sous-unités 23, 30, 49, et 51 kDa du complexe mitochondrial humain : application à l'étude des pathologies associées aux déficits du complexe I“. Université Joseph Fourier (Grenoble ; 1971-2015), 1998. http://www.theses.fr/1998GRE10053.
Der volle Inhalt der QuelleVergeade, Aurélia. „La dysfonction mitochondriale et la production d'espèces réactives de l'oxygène dans la dysfoncton cardiaque induite par la prise répétée de cocaïne“. Rouen, 2011. http://www.theses.fr/2010ROUENR09.
Der volle Inhalt der QuelleReactive Oxygen Species (ROS) have been implicated in cocaine-induced cardiac dysfunction. Although mitochondria' oxidative damage has been described in a variety of pathological models, the role of mitochondria as trigger or target of cardiac dysfunction remains unclear. We investigated the role of mitochondria in a model of cocaine-induced oxidative stress and cardiac dysfunction. Seven days of cocaine administration to rats led to a diastolic dysfunction. An increased oxygen consumption was detected in cardiac fibers, specifically through complex I and complex III. ROS levels were increased, specifically in interfibriliar mitochondria (IFM). In parallel there was a decrease in ATP synthesis, whereas no difference was obtained in subsarcolernmal mitochondria (SSM). The cardiotoxic effects of cocaine were completely prevented by the in vivo use of MitoQ, a mitochondria{ targeted antioxidant. Myocardial NADPH oxidase and xanthine oxidase contribute to ROS generation in cocaine-treated rats. Our results show that both apocynin and allopurinol, respectively NADPH oxidase and xanthine oxidase inhibitors, were able to improve ventricular relaxation. Further, apocynin or allopurinol treatments prevented the rise in ROS levels and prevented the — mitochondria' ATP synthesis alteration. In conclusion, cocaine-induced cardiac impairment is associated with an increase in ROS production via NADPH oxidase and xanthine oxidase. Our data suggested that this cardiac oxidative stress alters cardiac mitochondria" function by an uncoupling effect resulting in an increase in ROS production selectively in IFM, and leads to LV dysfunction
Haut, Sandrine. „Déficit en complexe III de la chaîne respiratoire mitochondriale : étude de cinq cas“. Paris 5, 2003. http://www.theses.fr/2003PA05P630.
Der volle Inhalt der QuelleThe ubiquinol-cytochrome c réductase (complex III of mitochondrial respiratory chain) deficiencies could be attibuated to mitochondrial or nuclear genetic origin. We identified 5 patients with an isolated complex III (CIII) deficiency. A molecular abnormality was found in two cases. In the first, an homoplasmic mutation was found in the mitochondrial cytochrome b (cytb) gene, the patient have a staturo-ponderal delay. The mutation was also present in two healthy individuals of family members. Studies carried out in vitro confirmed the pathogenic role of the mutation, already considered as a cardiomyopathy generating mutation in a previously reported case. In the second patient, we describe, for the first time, a mutation located in a nuclear gene encoding a structural subunit of CIII : the HUMQPC gene encoding the human ubiquinone-binding protein. This mutation induces a full reduction in cytb content and consequently destabilizes the CIII
Trzepizur, Wojciech. „Impact vasculaire et métabolique de l'hypoxie intermittente et de l'obésité dans un modèle murin“. Thesis, Angers, 2014. http://www.theses.fr/2014ANGE0038/document.
Der volle Inhalt der QuelleDecades increases the prevalence of many overweigh tassociated diseases including obstructive sleep apnea (OSA). Both OSA and obesity are considered as independent cardio-vascular and metabolic risk factors.The frequent association of OSA and obesity in clinical setting makes difficult to investigate their independent contribution to metabolic and vascular diseases. In the present thesis, we aimed to evaluate the impact of a short term intermittent hypoxia (IH), (animal model of OSA), of a high fat diet (HFD), and of both experimental conditions together (IH and HFD) on the vascular and metabolic outcomes. Short term IH alone had no impact on glucose and lipids levels and mitochondrial and vascular function. Animals fed with HFD presented dyslipidemia, hepatic steatosis, mitochondrial and endothelial dysfunction. Interestingly, when short term IH was applied to HFD fed mice, insulin level was increased, restored endothelial function and mitochondrial activity was restored and limited liver lipid accumulation was limited.Those data underline the polymorphic effects of IH that might target beneficial outcomes when applied for a short term in obesity, which contrast with the deleterious long term outcomes observed in OSA
Kolesnikova, Olga. „Importation mitochondriale d'ARN de transfert : Etude du mécanisme de transport chez la levure et application à la thérapie génique de maladies neuromusculaires humaines“. Université Louis Pasteur (Strasbourg) (1971-2008), 2002. http://www.theses.fr/2002STR13074.
Der volle Inhalt der QuelleIn the yeast S. Cerevisiae, a single nuclear-coded tRNA, tRNALysCUU (tRK1), is partially imported in the mitochondria, while the other lysine isoacceptor is restricted to the cytosolic (tRK2) compartment. To be imported, tRK1 must be aminoacylated by the cytoplasmic lysyl-tRNA synthetase and to interact with the precursor mitochondrial lysyl-tRNA synthetase. We constructed chimaeric tRNA transcripts containing in part sequences of tRK1 and in part sequences of tRK2, and tRK1 transcripts containing all possible one-base replacements in the anticodon. We found that the position C34 was a positive import determinant. Some mutant versions were imported in misacylated form. This was exploited to address the question of the functionality of the imported tRNA in mitochondrial translation. In vitro, we used the fact that the version tRK1CAU was imported in its methionylated form. After import of [35S]-methionine charged tRNA, we observed that the labeled amino acid was incorporated into mitochondrial translation products. In vivo, we developped a suppression assay in a strain bearing an Ala-to-amber mutation in the mitochondrial COX2 gene. The respiratory deficient phenotype could be suppressed by expression in the nucleus of an importable suppressor tRNA. We exploited these data to develop an artificial tRNA import system in human cells. Indeed, such a system could allow the use of gene therapy to cure mitochondrial diseases resulting from mutations in mitochondrial genes. We demonstrated that human mitochondria internalize tRK1 and several of its mutant versions in vitro and in vivo. We next used cybrid cell lines bearing mutation A8344G in the tRNALys gene (causing the MERRF syndrome). These cybrid lines are known to be respiratory deficient. Importable tRK versions were expressed in these cells and the clones expressing the transgenic tRNAs above a certain threshold level were shown to have partially recovered from their respiratory defect
Haut, Sandrine. „Place de la biologie moléculaire dans le diagnostic des cytopathies mitochondriales“. Paris 5, 1998. http://www.theses.fr/1998PA05P151.
Der volle Inhalt der QuelleAddo, Mathew Glover. „Identification of new nuclear genes involved in the mitochondrial genome maintenance“. Thesis, Paris 11, 2011. http://www.theses.fr/2011PA112065.
Der volle Inhalt der QuelleMitochondrial 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
Lejay, Anne. „Ischémie critique chronique des membres inférieurs : implication mitochondriale chez l'Homme et mise au point d'un modèle murin permettant l'évaluation de conditionnements pharmacologiques“. Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAJ078/document.
Der volle Inhalt der QuelleCritical limb ischemia defines an advances stage of peripheral arterial disease and peripheral arterial insufficiency. The diagnosis of critical limb ischemia requires three elements: clinical signs, arterial perfusion measures demonstrating the level of ischemia, as well as a duration of symptoms for more than 15 days. We developed a critical limb ischemia model in mice, nearly mimicking human pathology, by right femoral artery ligatuon followed by right artery ligation 4 days later. We then studied from this model the mitochondrial impairment associted with critical limb ischemia, including impaired mitochondrial respiratory function, reduced calcium retention capacity, and increased production of free radicals. Once these changes highlighted, we wanted to test different pharmacological conditioning, in order to identify protective molecules in critical limb ischemia. We thus demonstrated a protective effetct of N acetyl cysteine, statins and L-arginine. The protection pathways RISK and SAFE may be involved in this protective effect
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.
Der volle Inhalt der QuelleThe 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
M'Baya-Moutoula, Eléonore. „Impact de la signalisation calcique dans les maladies de la chaine respiratoire mitochondriale : étude du déficit du complexe II associé au syndrôme de Leigh“. Paris 5, 2009. http://www.theses.fr/2009PA05T053.
Der volle Inhalt der QuelleDespite advanced knowledge on the genetic basis of oxidative phosphorylation (OXPHOS)-related diseases, the molecular and/or cellular detenninants for tissue specific dysfunction are not completely understood. We studied the cellular events associated with initochondrial respiratory complex II deficiency in two models: human fibroblasts derived from a patient harbouring SDHA (succinate dehydrogenase subunit A) mutation and fibroblasts and neuronal derived cells treated chronically with complex II inhibitors. Mutation or inhibition of complex II were shown to determine a large increase of basal and agonist-evoked Ca2+ signals in the cytosol and the mitochondria, in parallel with initochondrial dysfunction (membrane potential (Δψmit) loss, [ATP] reduction and Reactive Oxygen Species (ROS) production). Cytosolic and initochondrial Ca2+ overload was shown to be associated with: i/ down- expression of SERCA2b and PMCA; ii/ increased ER Ca2+ leakage; iii/ decreased initochondrial motility; iv/ increased ER-mitochondria contact sites; and v/ increased initochondrial calcium uptake capacity. Interestingly, we showed that complex II deficient cells developed a Ca2+ dependent glycolytic ATP production. Moreover, increased mitochondria! Ca2+ load occurred prior to Av|/nl), loss and was shown to be implicated in the development of initochondrial pathology. These results revealed the importance of Ca2+ signalling in the control of the cellular bioenergetics outcomes linked to respiratory chain complex II deficiency. Our findings may help in the understanding of the pathology linked to complex II deficiency and to mitochondrial respiratory chain diseases in general
Caubère, Céline. „Molecular and functional interactions between apolipoprotein O and caveolin 3 in the heart : implication in the development of metabolic disorder-associated cardiomyopathy“. Toulouse 3, 2013. http://thesesups.ups-tlse.fr/2755/.
Der volle Inhalt der QuelleWith the dramatic modification of the lifestyle in the last century, new pandemic public health issues have emerged. The increase in the prevalence of obesity and its strong association with cardiovascular diseases has aroused interest in the understanding of mechanisms linking metabolic disorders and cardiac dysfunctions. It has recently emerged that cardiac altered energy metabolism, lipotoxicity, insulin resistance and mitochondrial alterations are leading causes in the development of metabolic or diabetic cardiomyopathy. Through a functional genomics study aimed at identifying genes differentially regulated in the heart by obesity, we discovered a new apolipoprotein (ApoO) which is also overexpressed in the myocardium from diabetic patients. In attempt to uncover how changes in the expression of this protein relate to modifications of cardiac function, we used cardiac myoblasts, human heart samples a well as cardiac specific transgenic mouse lines constitutively expressing ApoO at physiological levels. We show that ApoO localizes within mitochondria and induces mitochondrial dysfunction in mouse and human heart. ApoO interacts with adenine nucleotide translocase (ANT) which is known as mitochondrial permeability transition pore (mtPTP) regulator. This interaction enhances mtPTP opening, thereby inducing "mild uncoupling". Consequently, mitochondrial respiration, oxidative phosphorylation and fatty acid metabolism are enhanced. This cascade of events generates a mitochondrial metabolic sink whereby cells accumulate lipids and lipotoxic byproducts leading to apoptosis, loss of cardiac cells and cardiomyopathy, mimicking the metabolic phenotype of the diabetic heart. As a spin-off of these observations, we proposed a model for the original molecular mechanisms accounting for ApoO induced mitochondrial dysfunction and lipotoxicity. Besides, we observed that ApoO expressing cardiomyocytes develop adaptive mechanisms to protect cells from the ApoO-induced excessive oxidative metabolism. As revealed in human auricular heart samples and expression database from human heart ventricles, Caveolin-3 (Cav-3) expression is positively correlated to ApoO levels. Cav-3, the main caveolin isoform in cardiac myocytes, is known to have scaffolding domains that anchor and regulate the function of proteins, thereby modulating a variety of cellular processes. These properties make Cav-3 as an actor for cardiac protection. Interestingly, ApoO-induced metabolic stress, both in mouse heart and in vitro in cardiac cells, leads to a rise in Cav-3 levels and its translocation to mitochondria where it interacts with ApoO, through a direct association between the C-terminal scaffolding domain of Cav-3 and the specific aromatic caveolin binding motif (CBM) of ApoO. Blue native polyacrylamide gel electrophoresis of mouse heart mitochondrial protein complexes reveals that ApoO and Cav-3 are present in the same macromolecular complex with known mtPTP regulators. We show that ApoO and Cav-3 interaction results in a protective effect through reduction of ApoO-induced mild uncoupling and consequently restoration of coupled respiration and reduction in apoptosis. Site-directed mutagenesis in ApoO CBM domain prevents its interaction with Cav-3 and led to a loss of Cav-3-mediated protection, as reflected by strongly enhanced uncoupling which is considered as one hallmark of mitochondrial dysfunctions. Therefore, the involvement of ApoO and Cav-3 in mitochondrial homeostasis may reveal novel strategies to control pathophysiological situations involving mitochondrial dysfunctions, such as metabolic disorders and cardiomyopathies
Simon-Lombes, Anne. „Investigations moleculaires des maladies mitochondriales humaines“. Paris 5, 1997. http://www.theses.fr/1997PA05N003.
Der volle Inhalt der QuelleBarthélémy, Cyrille. „Variations spontanées et induites du nombre de copies de l'ADN mitochondrial“. Paris 7, 2001. http://www.theses.fr/2001PA077125.
Der volle Inhalt der QuelleAllard, Julien. „Mise en évidence de l'implication de différents mécanismes dans la survenue de la stéatose hépatique d'origine médicamenteuse en absence de dysfonction mitochondriale sévère“. Thesis, Rennes 1, 2020. http://www.theses.fr/2020REN1B010.
Der volle Inhalt der QuelleSteatosis is a liver lesion reported with numerous pharmaceuticals. Prior studies showed that severe impairment of mitochondrial fatty acid oxidation (mtFAO) constantly leads to lipid accretion in liver. However, much less is known about the mechanism(s) of drug-induced steatosis in the absence of severe mitochondrial dysfunction, although previous studies suggested the involvement of mild-to-moderate inhibition of mtFAO, increased de novo lipogenesis (DNL) and impairment of very low-density lipoprotein (VLDL) secretion. The objective of our study, mainly carried out in human hepatoma HepaRG cells, was to investigate these 3 mechanisms with 12 drugs able to induce steatosis in human: amiodarone (AMIO, used as positive control), allopurinol (ALLO), D-penicillamine (DPEN), 5-fluorouracil (5FU), indinavir (INDI), indomethacin (INDO), methimazole (METHI), methotrexate (METHO), nifedipine (NIF), rifampicin (RIF), sulindac (SUL) and troglitazone (TRO). Hepatic cells were exposed to drugs for 4 days with concentrations inducing loss of cellular ATP always below 30% of the controls and not exceeding 100xCmax. Among the 12 drugs, AMIO, ALLO, 5FU, INDI, INDO, METHO, RIF, SUL and TRO induced steatosis in HepaRG cells. AMIO, INDO and RIF decreased mtFAO. AMIO, INDO and SUL enhanced DNL. ALLO, 5FU, INDI, INDO, SUL, RIF and TRO impaired VLDL secretion. These 7 drugs reduced the mRNA levels of genes playing a major role in VLDL assembly and also induced endoplasmic reticulum (ER) stress. Thus, in the absence of severe mitochondrial dysfunction, drug-induced steatosis can be triggered by different mechanisms, although impairment of VLDL secretion seems more frequently involved, possibly as a consequence of ER stress