Дисертації з теми "Foie – métabolisme – Dissertation universitaire"
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Papegay, Bérengère. "Identification des mécanismes moléculaires de l'hépatoprotection du foie de rat isolé." Thesis, Lille 2, 2020. http://www.theses.fr/2020LIL2S015.
The protective effect of fasting has been observed in several areas of health. To study it, a rat liver model perfused exvivo was used here. In this model, we did not observe, for an 18h fasting, the protective effect reported for the liverin situ. However, we did emphasize the importance of the energy cost of the protective mechanism in the isolatedliver under experimental stress of ischemia/reperfusion and correlated protection with higher glycogen levels and anenergy load that required an exceeding threshold below which protection fades. The administration of energysubstrates (lactate and alanine) allowed us to confirm the energetic need for protection of the isolated liver. Then,increasing the duration of fasting of the donor rat from 18 to 24 hours proved to be hepatoprotective and, moregenerally, showed that the capacity for energy mobilization and, as such, autophagy contributed to hepatoprotection,the well-known energy cost of autophagy being in line with previous PhD work. Three candidate signaling pathwaysfor the activation of autophagy, involving AMPK, HMGB1 and ADP, were studied. Phosphorylation of AMPK wasincreased in fasted rat liver 24 hours vs. 18 hours. However, the addition of AICAR, an activator of AMPK, althoughincreasing its phosphorylation in isolated fasted rat liver 18h, did not induce protection. HMGB1 accumulation knownto induce autophagy, showed no correlation with markers of hepatic cytolysis (LDH) and autophagy (LC3II/Actin ratio).ADP, in its ADP/(AMP+ADP+ATP) and ADP/(AMP+ATP) ratios, was higher in 24-hour fasted rat livers and was correlatedwith hepatoprotection. ADP induced autophagy by activation of the membrane P2Y13 receptor, a specific inhibitor,MRS2211, was used. Its inclusion in the perfusate blunted the hepatoprotection and activation of autophagyassociated with prolonged fasting, validating the key role of this signaling in hepatoprotection.In conclusion, the Ph.D. allowed a substantial advance in the understanding of the role played by the nutritional statusof the donor on the hepatoprotection of the isolated liver. The identification of the molecular mechanisms ofhepatoprotection (energy mobilization, autophagy) and of its signaling (ADP, P2Y13 receptor) opens up innovativetherapeutic perspectives for liver diseases and new strategies for liver graft preservation. From a cell survivalperspective, autophagy ensures both a function of maintaining the quality of cellular components and an energeticrole. This maintenance of quality protects the cell and costs energy, making it indispensable for this type of protection.In other words, the maintenance preserves from deterioration and this protection has a cost that goes throughsignalling (internal funding decision) which, once identified, can now be requested as desired. Also, external financing(contribution of energy substrates) can be chosen or even added to the previous one
Delacôte, Claire. "Vers une meilleure compréhension de la maladie du foie liée à l'alcool et des facteurs influençant sa progression : approche de modélisation." Thesis, Lille 2, 2020. http://www.theses.fr/2020LIL2S029.
In France, excessive alcohol consumption is the leading cause of cirrhosis and hepatocellular carcinoma (HCC), ahead of viral hepatitis and metabolic syndrome. In 2016, there were nearly 10,500 deaths by cirrhosis or HCC, despite a significant decrease in per capita alcohol consumption since 1960 (26L in 1960, 11.7L in 2017).Alcohol drinkers are at risk of developing alcohol-related liver disease (ALD). It progresses from the initial stage of steatosis to more advanced stages of fibrosis and cirrhosis, which may lead to complications: decompensation and HCC. ALD is an asymptomatic disease prior to the onset of complications, and many patients are diagnosed late with life-threatening consequences.Implementing early actions targeting excessive alcohol drinkers could help to reduce liver morbidity and mortality through the avoidance or earlier diagnosis of complications. The evaluation of the possible benefit of such public health actions requires, on the one hand, knowledge of the different stages leading to the development of complications and, on the other hand, knowledge of the impact of risk factors on progression, in order to be able to determine the populations to target. Among the risk factors identified, the metabolic syndrome plays an important role. Thus, in order to understand the mechanisms of evolution of ALD, it is necessary to study in parallel those leading to non-alcoholic fatty liver disease (NAFLD).The natural history of ALD is still poorly described, especially for the stages preceding cirrhosis. Mathematical modeling provides a conceptual framework to overcome the ethical issues that would arise from a cohort study of the evolution of ALD.The main objective of this work is to mathematically reconstruct the natural history of ALD and to predict the associated morbidity and mortality. The secondary objectives are to estimate the incidence of this pathology and to identify the at-risk population. For this purpose, we developed a Markov model that simulates the trajectory of cohorts of individuals from the moment they start at-risk alcohol consumption until their death. It integrates the main risk factors described as associated with the progression of ALD in the literature (sex, age, overweight and obesity, amount of alcohol, genetic polymorphism). Unknown parameters of progression are estimated by a back-calculation method.Three steps were necessary to supply and calibrate this model : 1) characterize mortality by decompensated cirrhosis and HCC related to alcohol consumption or metabolic syndrome from data provided by the French National Hospital Discharge database; 2) set up a Markov model on hospitalization data of excessive consumers to estimate the progression of fibrosis; 3) implement a Markov model on survey data from the general French population to estimate the process of entry into at-risk alcohol consumption or the onset of overweight and obesity.In conclusion, this work is the first to characterize the progression of ALD in the general French population. It is based on robust epidemiological data to which new insights are provided. The developed tools could be used to test the impact of public health policies that could be implemented in populations most likely to develop liver damage
Deleye, Yann. "Rôle du gène suppresseur de tumeur p16INK4a dans le métabolisme hépatique des lipides au cours du jeûne." Thesis, Lille 2, 2018. http://www.theses.fr/2018LIL2S002.
P16INK4a is a tumor suppressor protein that is a well described cell cycle regulator. Recently, genome-wide association studies (GWAS) associated the CDKN2A locus, from which p16INK4A is encoded, with increased risk for development of type 2 diabetes. A pathophysiological link between p16INK4a and hepatic glucose homeostasis has been unraveled recently, through the control of gluconeogenesis. Patients with T2D also present with disturbances in fat metabolism, associated with an increased prevalence to Non Alcoholic Fatty liver diseases (NAFLD). In this context, we investigated the role of p16INK4a in hepatic lipid metabolism in vitro using primary hepatocytes, the murin AML12 and human IHH hepatocyte cell line transfected respectively with siRNA-CDKN2A and siRNA-p16 and in vivo using p16+/+ and p16-/- mice.Transcriptomic analyses of p16+/+ and p16-/- primary hepatocytes using microarrays revealed that metabolic and PPARα signaling pathways were among the most modulated in p16 absence. Moreover, in primary hepatocytes and in hepatocyte cell lines, p16 deficiency modulates a subset of PPARα target genes associated to fatty acids oxidation (FAO). These effects were associated with an increased response to GW647, a PPAR945; agonist, and reversed by siRNA targeting PPAR45;. Investigating known PPAR945; activators and transcriptional co-activators in vitro, we found that upregulation of FAO genes expression was linked to SIRT1. AMPK is a known activator of FAO and has been shown to induce SIRT1 activation through increase of NAD/NADH ratio. Interestingly, downregulation of p16 expression in vitro led to increased AMPK phosphorylation and activation.In vitro, p16-/- primary hepatocytes demonstrated enhanced fatty acid oxidation of oleate compared to p16+/+. During fasting, enhanced FAO leads to a shift of acetyl-coA utilization from the TCA cycle to ketogenesis. Interestingly, p16-/- mice showed a tendency to produce more ketone bodies than their control littermate after sodium octanoate injection. These findings describe a new function for p16INK4a in hepatic lipid metabolism through activation of AMPK-SIRT1-PPARα pathway
Gilles, Mélissa. "Nouvelles fonctions de la protéine Tau dans le métabolisme des ARN." Thesis, Lille 2, 2018. http://www.theses.fr/2018LIL2S054.
Tauopathies are neurodegenerative diseases characterized by an intraneuronalaggregation of hyperphosphorylated Tau proteins. The accumulation of these lesionsinduces neuronal dysfunctions leading to cells death. It has been established that Taudysfunctions play a central role to the neurodegenerative process. However, thephysiological functions of these proteins are still incompletely understood. Tau was first described as a microtubule associated protein involved in microtubule stabilization.However, it has been shown that Tau displays additional functions depending of itscellular localization. In the cytoplasm, Tau regulates axonal transport, synapticfunctions and signaling pathway. Tau was found also in the nuclear compartmentwhere it is involved in nucleic acid protection, organization of neuronal pericentromericheterochromatin and expression of ribosomal genes. In addition, studies have demonstrated an interaction between Tau and several RNA binding proteins, known to play a role in RNA metabolism. Moreover, dysfunctions of this mechanism havebeen reported in tauopathies.To gain insights into roles of Tau in RNA metabolism, we used tandem affinity purification coupled to mass spectrometry to identify novel interaction partners. Weidentified DDX5, a DEAD box RNA helicase, as a novel interacting partner. DDX5 is aprotein involved in several RNA metabolic processes such as, transcription, splicing,ribosome and micro RNA biogenesis and nonsense mediated mRNA decay (NMD). Inthis work, we validated Tau-DDX5 interaction and identified the Tau sequence involvedin the interaction. We also showed that this interaction is modulated in a RNA dependent manner and identified the presence of DDX17, another DEAD box RNAhelicase, in this complex. Our results demonstrated that Tau positively regulatesmRNA degradation by NMD pathway in a DDX5 dependent manner. We also shownthat Tau negatively regulates pre-mRNA splicing and expression of splicing factorsPTBP1 and PTBP2. The NMD is known to modulate expression of some splicingfactors through a system called “Alternative splicing coupled to NMD” (AS-NMD)suggesting that Tau effect on splicing could be dependent of NMD activation.Interestingly, Tau phosphorylation, especially the threonine 231 known to be involvedin tauopathies, increased the effect of Tau on NMD pathway.Altogether, our results highlight a link between Tau and the DEAD box RNA helicaseDDX5 and demonstrate an unexpected role of Tau in regulating splicing and NMD pathway. Our findings suggest that a loss of Tau functions may participates directly tothe splicing and NMD target genes misregulation observed in tauopathies
Köysüren-Demirkapi, Nursel. "Étude de l'élongation des acides gras NADH-dépendante dans le réticulum endoplasmique de foie : mécanisme de régulation au niveau de la B-cétoréduction." Paris 11, 1989. http://www.theses.fr/1989PA11A002.
Garçon, Damien. "Effet intestinal de PCSK9 au delà du métabolisme du cholestérol : focus sur la lipémie postprandiale et l'allergie alimentaire." Thesis, Nantes, 2020. http://www.theses.fr/2020NANT1011.
PCSK9 (ProProtein Convertase Subtilisin Kexin Type 9) is the 3rd gene responsible for familial hypercholesterolemia. Indeed, PCSK9 is a natural inhibitor of the LDL receptor. Patients with PCSK9 gain function mutations are at very high risk for cardiovascular disease. In addition to its impact on cholesterol metabolism, PCSK9 plays a role in another cardiovascular risk factor: postprandial lipemia. This phenomenon, characterized by a rise in plasma triglycerides after a meal, is a risk factor for cardiovascular disease in certain pathologies, particularly in patients with type 2 diabetes. It has been shown that mouse models deficient in PCSK9 have a reduction in their postprandial lipemia. During my thesis, we showed by using deficient mouse models, inhibition of PCSK9 by anti-PCSK9 antibodies and the development of an original model of intestinal PCSK9 deficiency that the circulating form of PCSK9 is crucial in the phenomenon of postprandial lipemia. Beyond lipid metabolism, PCSK9 has been shown to play a role in inflammatory responses, particularly during septic shock. In my thesis, we observed the impact of PCSK9 deficiency and inhibition on the food allergy development. We showed that the absence of PCSK9 protects against the onset of allergy symptoms. My thesis has therefore highlighted the role of PCSK9 beyond cholesterol metabolism and at the intestinal level
Woller, Aurore. "Entrainment of the mammalian circadian clock by metabolism in the liver : a quantitative mathematical model." Thesis, Lille 2, 2016. http://www.theses.fr/2016LIL2S036/document.
To anticipate daily changes in their environment, most living organisms have evolved a circadian clock, which is synchronized to the diurnal cycle and orchestrates numerous biological functions. At organismal level, daylight is the main signal driving the clock. In multicellular organisms, however, clocks in peripheral organs respond to other cues. For example, the liver clock is primarily synchronized by fasting/feeding cycles and variations in the cellular metabolic state, as reflected by the NAD+/NADH and ATP/AMP ratios. To better understand the entrainment of peripheral circadian clocks by metabolic cycles, we have constructed a mathematical model of the mammalian circadian clock incorporating the metabolic sensors SIRT1 and AMPK. This model reproduces accurately experimental clock gene expression data from mouse liver in vivo and predicts correctly the effect of SIRT1 or AMPK loss-of-function. We used our mathematical model to investigate the response of the liver clock to various temporal patterns of AMPK activation, mimicking the effect of a normal diet, of fasting and of a high-fat diet feeding. Our results predict significant changes in clock gene expression and NAD+ time profiles between these situations. They suggest that the night peak in NAD+ level is due to circadian rhythms in NAMPT expression, while the day peak results from transient AMPK activation. Finally, we find that the loss of amplitude in expression rhythms observed when AMPK is depressed may be pharmacologically rescued using a timed REV-ERB agonist administration, suggesting strategies to fight against high fat diet-induced obesity
Tirou, Linda. "Rôle de la voie de signalisation Sonic Hedgehog dans les cellules Glast positives du cerveau de souris adulte C9C5 Positive Mature Oligodendrocytes are a Source of Sonic Hedgehog in the Mouse Brain Hedgehog Controls Quiescence and Activation of Neural Stem Cells in the Adult Ventricular-Subventricular Zone." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASL022.
During embryogenesis, the Sonic Hedgehog (Shh) signaling pathway plays a key role in neural patterning. The pathway is still active in the adult rodent brain where it participates to the maintenance of neural stem cells (NSCs), to neuronal and glial circuitry and to tissue repair (Ruat et al, Top. Med. Chem., 2015). In the adult brain, the astrocytes, glial cells regulating trophic support and activity of neurons, are proposed as the main Shh-responsive cells (Garcia et al, J. Neurosci., 2018). However, the implication of Shh signaling in these astrocytic functions is still poorly characterized. Here, I investigated the role of Shh signaling in astrocytes using various genetic, molecular, biochemical and pharmacological approaches. I used the transgenic mouse line Glast-CreERT2-YFP-Ptc-/- (YFP-Ptc-/-), a model of conditional deletion of the Shh receptor Patched (Ptc) in Glast-expressing cells, and their control littermates, YFP-Ptc+/+ mice. Tamoxifen-mediated recombination in YFP-Ptc-/- mice during adulthood led to Ptc deletion and YFP reporter expression specifically in Glast+ cells, namely astrocytes, NSCs and their progeny. I provided the first detailed analysis of Shh pathway transcripts expression (Ptc, Gli1, Gli2, Gli3) in astrocytes using single-molecule fluorescent in situ hybridization (smFISH) combined to immunohistofluorescence in various brain regions, including the hypothalamus. Moreover, I identified a subpopulation of mature oligodendrocytes (OLs), expressing the OLs markers CC1, Olig2 and Sox10, as a potential source of Shh ligand for these astrocytes and for neurons expressing Ptc in the postnatal brain. I demonstrated the presence of Shh protein and transcripts in these cells using the specific Shh monoclonal antibody C9C5 and smFISH, respectively. The characterization of YFP-Ptc+/+ and YFP-Ptc-/- mice metabolic phenotype at different timepoints revealed the implication of astrocytic Shh pathway in the regulation of whole body energy insulin tolerance tests. This effect was maintained over time and associated to lower blood insulin levels. YFP-Ptc-/- mice also exhibited a strong lean phenotype related to the absence of body weight gain. They presented a reduction of white and brown adipose tissues accompanied by an increase of fatty acid oxidation evaluated in metabolic cage, while food intake, locomotor activity and body temperature were not altered. Thus, the activation of astrocytic Shh signaling counteracted age-associated but also diet-induced metabolic alterations. At the cellular level, Ptc deletion did not affect glucose uptake in primary astrocyte cultures suggesting that these effects are mediated by another mechanism. In the hypothalamus, a key region in the control of energy homeostasis, the activation of astrocytic Shh pathway led to an increase of insulin signaling genes expression. Altogether, these data argue for a novel important role of Shh signaling in astrocytes for hypothalamic regulation of energy metabolism. The phenotype analysis of YFP-Ptc+/+ and YFP-Ptc-/- mice also revealed a key role of Shh signaling in orchestrating the quiescence and activation of NSCs in the ventricular-subventricular zone of the lateral ventricles, one of the main adult neurogenic niche. Long term activation of Shh pathway in NSCs induced an increase of quiescent NSCs number while activated NSCs and their progeny were strongly depleted affecting neurogenesis in this region. Overall, this work highlights novel properties of Shh signaling that will allow deeper understanding of its functions in the adult brain, and widens the therapeutic potential of pharmacological modulators of this pathway to neurodegenerative, demyelinating and metabolic disorders
Godoy, José Luiz de. "Régénération hépatique et transfert de gènes." Paris 5, 1999. http://www.theses.fr/1999PA05CD04.
Mazuy, Claire. "Etude de l’interaction entre le récepteur nucléaire FXR et le facteur de transcription FOXA2 dans le foie." Thesis, Lille 2, 2015. http://www.theses.fr/2015LIL2S055/document.
The liver is a key regulator of whole-body energy metabolism. The nuclear receptor super-family plays a leading role in the metabolic sensing of the liver. Among the nuclear receptors, the bile acid nuclear receptor FXR contribute to the modulation of liver activity in particular through the regulation of bile acid, lipids and glucose homeostasis. Consequently, FXR became a potential therapeutic target for many diseases implicated metabolic disorder such as cholestasis, type 2 diabete or Non-Alcoholic Steatohepatitis (NASH). Despite promising results especially on NASH, patient treatment with FXR agonist the INT747 seems to increase LDL-Cholesterol plasma concentrations together with a decreased concentration of HDL-Cholesterol suggesting a higher risk to develop atherosclerosis. These effects on plasma lipid profile are the major break against the development of agonists in clinics. Giving the poor understanding and knowledge of the molecular mechanisms which govern FXR regulation of activity on various signaling pathways, it is of major interest to find new partners and regulators of FXR and especially on lipid and cholesterol homeostasis. One of the transcription factor known to be active in the control of these signaling pathways in the liver is the forkhead box transcription factor FOXA2. This transcription factor whose activity is dependent of physiological conditions is activated by glucagon and inhibited by insulin. In addition, this factor is known to regulate bile acid, cholesterol and lipid metabolism, functions very close from FXR activities in the liver.The objective of this PhD was to study the interaction between FXR and FOXA2 signaling pathways in different hepatic cells lines from human or mouse origin and in the liver. We established that FOXA2 and FXR are colocalised in HepG2 cells and liver chromatin near genes implicated in the lipid and cholesterol metabolism. These FXR/FOXA2 cobinding zones present few consensus FOXA2 response elements suggesting the implication of non consensus binding motifs or a “tethering” mechanism. We show that FOXA2 binding to FXR/FOXA2 cobinding zones is increased when FXR is activated and/or more present in the chromatin evoking a potential interaction between these two factors. We demonstrate that FXR and FOXA2 interact physically and that FOXA2 is a repressor of FXR transcriptional activity using different approaches and cellular models. Finally, we show that FOXA2 is implicated in glucagon-induced repression of FXR transcriptional activity on Shp gene.To conclude, our results show for the first time that the fasting key regulator of lipid and cholesterol homeostasis FOXA2 is a repressor of FXR transcriptional activity through a plausible mechanism involving “tethering” process. This work gives a novel mechanism by which FXR activity can be modified by nutritional status in a gene-specific manner
Cuffaro, Bernardo. "Analyse fonctionnelle de bactéries du microbiote intestinal humain et évaluation de leurs propriétés bénéfiques contre l’obésité et l’inflammation intestinale." Thesis, Lille 2, 2021. http://www.theses.fr/2021LIL2S007.
Alterations in the gut microbiota composition are suggested to play a role in the development of chronic diseases, including obesity and inflammatory bowel disease (IBD). This dysbiosis leads to the disruption of several key biological processes known to regulate the host physiology, notably the gut barrier integrity and the immune responses leading to a pro-inflammatory state. There is also an alteration in the production of Short Chain Fatty Acids (SCFA), key bacterial metabolites that regulate host metabolism by stimulating the secretion of endocrine peptides. Microbiota-targeting interventions therefore represent interesting tools in the management of chronic diseases. The knowledge on the composition and functions of the gut microbiota has extended the range of microorganisms with potential health benefits. These microorganisms are likely to be fully adapted to the gastrointestinal tract environment and to have important interactions with the host and for these reasons they are being evaluated as next generation probiotics (NGPs). We selected dominant bacteria from the gut microbiota and we checked their robustness to environmental conditions such as oxygen-tolerance and their capacity to survive to gastric stress and observed a strain-dependent capacity. We further characterized their potential beneficial activities using different in vitro models. Most of them were able to induce the release of SCFA in the culture supernatants, mainly acetate and to a lower extend propionate or butyrate. Among the screened strains, a majority was able to restore the gut barrier in an in vitro gut epithelial (Caco-2) barrier model and several strains exhibited an anti-inflammatory potential after human immune cells (PBMC) stimulation and/or were good inducers of GLP-1 after STC-1 endocrine cell line stimulation. Interestingly some ofthem combined several properties. We then evaluated in vivo the most promising strains in different murine models of diet-induced obesity and colitis. We identified three strains exhibited promising abilities against obesity. We also showed a strain-dependent effect of Parabacteroides distasonis strains against colitis and selected three effective strains. These studies provide us better insights on the functionality of commensal bacteria and crucial clues to select next-generation probiotics able to target inflammatory chronic diseases such as obesity and related disorders or IBD
Plancke, Charlotte. "Étude du métabolisme de l'amidon chez les Archaeplastida : le cas de l'algue glaucophyte modèle unicellulaire Cyanophora paradoxa et de l'algue rouge multicellulaire Chondrus crispus." Thesis, Lille 1, 2008. http://www.theses.fr/2008LIL10052/document.
Starch and glycogen both define the most wide-spread storage polysaccharide in the world. The starch appearance in the eukaryotic lineage coincides with a single endosymbiotic event occurring 1,6 billion years ago between a cyanobacteria and a primitive eukaryotic hosto From this event appeared three photosynthetic lines: Chloroplastida (land plants and green algae), Rhodophyceae (red algae and organisms which are diverted from the Rhodophyceae by secondary endosymbiosis) and Glaucophyta. The plastid starch biosynthesis pathway in Chloroplastida is relatively weIl characterized. For the Rhodophyceae (cytosolic starch) studies have already been initiated but the information obtained is still incomplete and not representative of the lineage. Finally for the Glaucophyta, which diverged in a more premature way after the event of endosymbiosis no information about this (cytosolic) starch metabolism was available. To discover the biosynthesis pathway used by these organisms, we decided to perform the complete characterization of the starch biosynthetic pathway for two differents organisms: The Glaucophyta named Cyanophora paradoxa and the Rhodophyceae named Chondrus crispus. This manuscript of PhD mainly presents information on the Floridian starch metabolism of Cyanophora paradoxa. The starch characterisation of Chondrus crispus is currently at the preliminary stage and will require further development
Eysert, Fanny. "Etude des mécanismes impliquant le facteur de risque génétique FERMT2 dans le métabolisme de l’APP et ses conséquences dans le processus physiopathologique de la maladie d’Alzheimer." Thesis, Lille 2, 2019. http://www.theses.fr/2019LIL2S040.
The establishment of genome-wide association study (GWAS) constitutes a major advance for the identification of new genetic susceptibility factors of Alzheimer’s Disease (AD). In contrast with the target gene approach, these analyses are done sans a priori and do not allow us to determine the role of the identified genes in the pathophysiological process of AD. In this context, only performing "post-GWAS analyses" can explain the molecular processes involving these genes. Our laboratory therefore aimed to identify the genetic risk factors identified by GWAS whose expression levels impact the APP metabolism. Moreover, our model allowed us to study the potential involvement of micro-RNAs (miRs) in the dysregulation of the expression of these genes.In this context, we showed that miR-4504, which is overexpressed in the brains of AD patients compared with controls, decreases the expression of FERMT2, a genetic susceptibility factor of AD. Our results show that FERMT2 under-expression is dependent on the presence of a variant (rs7143400) localized in the 3'UTR of FERMT2, which then leads to the modulation of the APP metabolism and the subsequent increase in Aβ peptide secretion.In this project, I was able to show that the effects of FERMT2 on APP metabolism require its direct inter-action with APP. In addition, using a model of primary neurons cultured in microfluidic devices enabled me to study neuronal functions of the FERMT2/APP complex. I was able to determine that FERMT2/APP interaction contributes to the regulation of axonal growth and synaptogenesis. Finally, by analyzing the long-term potentiation in the brains of mice in which FERMT2 under-expression was induced, we show a decrease in synaptic plasticity – potentially the underlying mechanism of the deleterious effect of decreased FERMT2 expression in neurons and of the pathophysiological process of AD.In conclusion, these results suggest that the genetic risk factor FERMT2, regulated by the presence of the functional variant rs7143400 and miR-4504, participates in the pathophysiological process of AD via synaptic alterations in an APP-dependent manner. This work would ultimately lead to a better understanding of the pathophysiological process leading to AD and help characterize new mechanisms involved in synaptic functions
Girault, Tiffanie. "Etude du photocontrôle du débourrement du bourgeon chez le rosier ( Rosa sp. L) : impact de la lumière sur le métabolisme glucidique et l'élongation cellulaire." Angers, 2014. https://tel.archives-ouvertes.fr/tel-00960749.
The aesthetic quality of ornamental plants is affected by several criterions, including the global shape of the plant. It is the result of buds activity along stems and of the growth of the shoot produced. In many plants, environmental factors have a strong impact on plant architecture, which generates this form. Among these factors, light, both in intensity or in quality, may modulate the ability of bud to burst. Apart from this observation made in several species, only few studies have tried to identify the mechanisms involved in the light control of this process. To address this issue, we have started works on many rose bush varieties. These works are based on morphological, histological, biochemical and molecular studies. Our studies were carried out on experimental plants, defoliated and decapitated over the three basal buds of the main stem. Working on such plant model allows to limit the impact of correlative inhibitions between organs, which may block or interact with the mechanisms of photocontrol. Our results demonstrate that light is absolutely required to trigger bud burst in rose. Indeed, no bud burst occurred under darkness among the six varieties studied, which is not the case in most species like Arabidopsis thaliana, tomato or poplar. Shading experiments have shown that bud directly perceives the light signal necessary for burst, thus indicating that a short-distance signalling takes place between the receptive organ (bud scales) and the growing organs (shoot apical meristem, young leaves). Light, both in terms of intensity and quality, modulates bud burst. Thus, low light intensities (2 +mol. M-2. S-1) are sufficient to allow the growth of preformed leaves but not to trigger the shoot apical meristem organogenic activity. Blue and red lights, unlike far-red light, induce both these processes. A question comes up then: what are the key physiological processes involved in bud burst that are under light control ? Two physiological processes have been particularly studied : sugar metabolism and cell wall expansion. Our results show that, under light, bud bursting is associated with an influx of water and sugars in the bud, and with sucrose degradation into fructose and glucose. Light acts by promoting the transcription of genes and/or the activities of sucrose degradation enzymes such as vacuolar acid invertase and sucrose synthase. Cell elongation is also stimulated in light conditions as shown by our scanning electron microscopy experiment. Under darkness, these processes are reduced or inhibited and do not offer the optimal conditions necessary to bud burst. Thus, gene expression of an expansin, a protein involved in cell wall loosening during cell elongation, is highly reduced. In response to the stress caused by a long dark period, an increased transcription of a sorbitol dehydrogenase gene takes place, that could take over from sugar metabolism for cell survival. Thus, our study demonstrates that the photocontrol of bud burst occurs through at least two physiological processes : sugar metabolism and cell elongation. Given our results and those of the literature, we propose a model of control of bud burst by light
Guilbaud, Axel. "Effet du Lactobacillus fermentum ME-3 sur la glycation et les désordres métaboliques dans un contexte diabétique de type 2." Thesis, Lille 2, 2018. http://www.theses.fr/2018LIL2S051.
Type 2 diabetes is a metabolic pathology characterized by chronic hyperglycemia. The disease progressively induces organ damage through several mechanisms, one of the which is the glycation pathway. This chemical reaction results in a bond forming between a reducing sugar and the amine function of an amino acid, a peptide or a protein. Over the last 30 years several studies have described therapeutic strategies to reduce the formation and accumulation of glycation products. Scientists have investigated synthetic or natural molecules that can metabolize or sequester precursors of glycation products. Others have tried to inhibit the main receptor of advanced glycation endproducts (RAGE) with specific antibodies or receptors. Despite these efforts, there is still no effective “anti-glycation” treatment able to reduce glycation products in the organism or limit their deleterious effects on health.Scientists have recently investigated the gut microbiota, and notably the actions of probiotics on glycemic parameters and the complications associated with diabetes. Preclinical and clinical trials have shown the effect of certain probiotics on weight gain and upon glucose metabolism. But while these studies have reported the effect of probiotics on different glucidic parameters, no one has yet investigated their effect on glycation.Thus, the double goal of this thesis was to compare different rodent models of glycation in a type 2 diabetes context (genetic and dietary-induced obesity (DIO) models), and then to use the most pertinent model to study the effects of a specific bacterial strain, Lactobacillus fermentum ME-3, on glycation and metabolic disorders in this diabetic context. The ensemble of glycation products measured, namely furosine, free and protein-bound carboxymethyllysine (CML) in organs and in plasma, were performed by liquid chromatography coupled with tandem mass spectrometry.Firstly, we showed that the genetic LepRdb/db model of diabetes exhibited significantly greater glycation in tested organs and fluids (kidneys, lungs, heart, liver and plasma) compared with DIO models (High Fat and High Fat High Sucrose Diet) which, despite dietary-induced weight gain and glucose intolerance, showed no significant increase in furosine or CML levels.Secondly, using the genetic model of diabetes, we showed that a treatment with ME-3 over three months in wild-type mice (LepRdb/+) and LepRdb/db had beneficial effects upon weight gain (-4.6% and -14% in db/+ and db/db mice, respectively) and glucose tolerance. We also observed a reduction of furosine levels in kidneys (-14.5% and -12.3% in db/+ and db/db mice respectively) and a reduction of free CML in both the kidneys (-18% and -25% in db/+ and db/db mice, respectively) and the lungs (-10% and -19% in db/+ and db/db mice, respectively). This preclinical study observed other effects of the ME-3 strain on health. Among these, the most marked was a reduction in development of hepatic steatosis (-23% and -41% of hepatic triglycerides, -12% and -21% of ALAT (a marker of liver injury) in db/+ and db/db mice, respectively; and a 27% reduction in db/db mice of TNF-α, an inflammation marker).To conclude, this work has characterized a rodent model of type 2 diabetes for the study of glycation and future development of therapeutic strategies against glycation. It has also highlighted the beneficial effects of the ME-3 strain on both glycation and metabolic disorders in a type 2 diabetes model
Sermikli, Benan Pelin. "Role of the nuclear receptor RORα expressed by myeloid cells in metabolic diseases". Thesis, Lille 2, 2020. http://www.theses.fr/2020LIL2S019.
RORa (Retinoic acid receptor-related orphan receptor-alpha) est un facteur de transcription de la superfamille des récepteurs nucléaires exprimé par des cellules immunitaires et non immunitaires impliqué dans le contrôle de l'obésité, de l'insulinorésistance (IR) et de la stéatohépatite non alcoolique(NASH). Le cholestérol, le cholestérol-sulfate, les stérols 7-oxygénés et les oxystérols ont été identifiés comme des ligands endogènes potentiels RORa. Pour mieux comprendre le rôle de RORa exprimé parles macrophages dans l'obésité et I’IR, nous avons généré une lignée de souris déficientes en RORa spécifiques aux macrophages (MKO) en utilisant des lignées de souris LysM-Cre et RORa foxée. Nous résultats montrent que l’inactivation de RORa dans les macrophages n'a pas d'impact sur l'obésité et l’insuline-résistance induites par une régime riche en graisses (HFD). Étonnamment, contrairement àdes travaux, notre étude ne montre pas d'effet sur le développement de la NASH ni suite à un régime HFD, ni dans le modelé d’alimentation défini par les acides aminés L, plus sévère et indépendant de l 'obésité et déficient en choline. Nous avons donc soupçonné que le nombre de copies de LysM pouvait jouer un rôle dans cette divergence, car le génotype des souris au l locus LysM est une différence majeure entre les deux études indépendantes. Les souris LysM-Cre portent une insertion de la recombinase Cre dans le gène Lyz2, ce qui conduit à l'expression de Cre sous le contrôle du promoteurLyz2 et ses activateurs, mais abolit l'expression endogène de Lyz2. Alors que nous avons intentionnellement maintenu une expression similaire de Cre et de Lyz2 entre WT et MKO en utilisant uniquement des animaux hémizygotes pour ce locus (en comparant Rora+/+Lyz2Cre/+ avec Rorafl/flLyz2Cre/+), des souris foxées (Rorafl/flLyz2+/+) ont été utilisées comme contrôle de WT et comparées avec des souris MKO pour lesquelles il manquait des informations sur le locus Lyz2(Rorafl/flLyz2Cre/ ?) dans l'étude antérieure. Aussi, nous avons émis l'hypothèse que l'impact observé de la délétion de RORa dans les macrophages sur la NASH dans l'étude précédente ne résultait probablement pas d'un effet spécifique de la délétion de RORa, mais plutôt d'un nombre de copies Lyz2différent entre les souris WT et MKO et avons décidé de vérifier cette hypothèse expérimentalement.De manière surprenante, nos résultats préliminaires ont montré que les souris déficientes en Lyz2présentent une légère protection, plutôt qu'un effet néfaste, dans l'obésité et l'IR induites par le HFD,comme le montre la diminution du poids corporel et des masses de tissu adipeux, l'amélioration significative du contrôle de la glycémie et la diminution de l'inflammation de l'épiAT. Il est intéressant de noter que la déficience totale en Lyz2 n'a eu aucun impact sur la stéatose hépatique (NAFL) chez les souris nourries au HFD. Néanmoins, nos résultats préliminaires suggèrent même que la carence enLyz2 pourrait protéger contre la NASH induite par le régime alimentaire, carence en choline. Dans leur ensemble, ces résultats préliminaires indiquent que le nombre différent de copies du gène Lyz2 chez les souris de contrôle n'explique probablement pas la différence entre notre travail et l'étude précédente.Globalement, nos résultats montrent que la délétion de RORa dans les macrophages ne modifie pas le développement de l'obésité et de l’IR et remettent en question son rôle dans la NASH. D'autre part,nous pensons que des recherches plus approfondies sur le rôle du lysozyme présentent un intérêt significatif dans le contexte de l'obésité, de l’IR et de la NASH avancée, car Lyz2 pourrait avoir un intérêt thérapeutique
Bollier, Melanie. "Conception et synthèse de purines substituées en positions C8 et N9 en tant qu'antagonistes potentiels du récepteur NOD1 en vue de limiter les lésions d'ischémie-reperfusion hépatique." Thesis, Lille, 2018. http://www.theses.fr/2018LILUS058.
In Europe, liver transplantation is facing a lack of donation and the few available organs are threatened by the ischemia-reperfusion (I-R) phenomenon. Recently, the LIRIC revealed the role of NOD1, a cytoplasmic pattern recognition receptor, in this phenomenon. The NOD1 receptor is an intrinsic central regulator of polymorphonuclear neutrophils (PMNs) migration and phagocytic capacities. The NOD1 receptor regulates also the interaction between PMNs and hepatocytes and consequently the PMN-induced hepatocyte lysis. It is interesting to note that in an I-R model, nod1-/- mice are protected from hepatic I-R injuries. In this model, mice treated with ALINO73, a NOD1 signaling pathway inhibitor from the literature, analogue of SB711, are also protected from hepatic I-R injuries. These results suggest that the development of NOD1 antagonists is a potential therapeutic solution to minimize hepatic I-R injuries.A 3D virtual model of the NOD1 LRR domain, the recognition domain, was developed in the LIRIC. Using this model and a rational design strategy, a new chemical series as potential NOD1 antagonist was identified, the arylimidazole series and more exactly, a series of C8 and N9 disubstituted purinergic compounds.These potential NOD1 antagonists have been synthesized using two strategies: one by imidazole annulation in one or two steps, another one starting from adenine. A total of fifty-seven final compounds were obtained with moderate to good yields. Part of these compounds was evaluated using an in vitro assay to identify their capacity to block NOD1-mediated NFκB signaling pathway.These synthesized compounds will also be evaluated by surface plasmon resonance (SPR) and thermophoresis to determine their affinity for NOD1. The identified NOD1 antagonists will be evaluated in ex vivo and in vivo models after determining their ADME-Tox properties in vitro
Ferlin, Juliette. "Etude de la voie de signalisation GBF1-ARF au cours de la réplication virale." Thesis, Lille 2, 2018. http://www.theses.fr/2018LIL2S047.
GBF1 has recently emerged as a cellular factor essential for the replication of single-stranded positive-sense RNA ((+)RNA) viruses from different families. GBF1 is a guanine-nucleotide exchange factor of small G proteins of the Arf family, known to regulate the early secretory pathway. By studying the hepatitis C virus (HCV) as a model, we have shown that the role of GBF1 in viral replication is distinct from its regulatoryfunction of the sercretory pathway. Indeed, GBF1 function in HCV replication is mediated by Arf4 and Arf5,whereas another pair, Arf1 and Arf4, mediates the regulation of the secretion. To determine if this mechanism ofaction is conserved among (+)RNA viruses, we showed that GBF1 is involved in yellow fever virus (YFV),sindbis virus (SINV), human coronavirus 229E (HCoV-229E) and coxsackievirus B4 (CVB4) infection. Our results indicate that YFV, SINV and HCoV-229E infections are Arf4 and Arf5 dependent, as we previouslyshowed for HCV. However, YFV and SINV would also use another Arf pair, Arf1 and Arf4, during their lifecycle. In addition, CVB4 infection depends on GBF1, but doesn’t seem to depend on any Arf. Although GBF1 is required for (+)RNA viruses replication, its mechanism of action appears not to be conserved.The Arf4-Arf5 pair appears to be involved in the replication of several (+)RNA viruses. However, these twoproteins have been poorly studied so far, contrary to Arf1. Our hypothesis is that the Arf4-Arf5 pair regulatesspecific effectors involved in viral replication. Our results indicate that Arf4 and Arf5 simultaneous depletionalters the morphology of the Golgi apparatus, which becomes condense, and of lipid droplets (LD), whichaccumulate and grow bigger at the cell periphery. However, a lipidomic analysis of Arf4 and Arf5 depleted cellsdisplayed an unaltered lipid composition, which suggests a morphologic impact on LD, rather than a disruptionof the lipid metabolism. A transcriptomic analysis identified proteins up- or down-regulated after Arf4 and Arf5 depletion. We assessed the function of some of these proteins in HCV replication, but none of them proved implicated.In conclusion, our results hightlighed new GBF1 functions, mediated by the pair Arf4-Arf5. Arf4 and Arf5 are involved in regulating the morphology of Golgi complex and of LDs, as well as the replication of (+) RNA viruses. It remains to assess if these functions are independent or related to each other, and which specific effectors they use
Soulé, Stéphanie. "Caractérisation fonctionnelle de jouvence, un petit ARN nucléolaire requis dans l’épithélium de l’intestin chez la drosophile ninaD Regulates Cholesterol Homeostasis From the Midgut and Protects Against Neurodegeneration Jouvence a Small Nucleolar RNA Required in the Gut Extends Lifespan in Drosophila." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASL054.
The massive ageing of the population and the incredible leap in life expectancy in recent decades have led to an awareness of the importance of this problem. The need to better understand the mechanisms of ageing has become a public health emergency. Many research groups have been working for several years to identify genes and signalling pathways involved in the aging process.This biological process, which affects each species and each individual independently, is characterized by a gradual decline of function of many physiological processes as a function of age. However, even though it is inevitable, aging is still subject to influence. Indeed, many factors, both intrinsic (genetic factors, telomerases, oxidative stress) and environmental (lifestyle, diet, pollution) will influence aging. Aging is also an important risk factor for the development of many diseases such as type 2 diabetes, cancer, neurodegenerative and cardiovascular diseases. Moreover, it has already been reported in the literature that modulation of a single gene can influence, both positively and negatively, the aging process of an individual. More than the extension of life expectancy, it is a life expectancy without deficiency (concept of "aging well") that is the subject of major research. Genes with effects on this process are usually genes that play an important role in a signalling pathway, and therefore are often conserved across evolution. The work described in this thesis shows the involvement of a new snoRNA (jouvence), required in the intestinal epithelium, in the aging mechanisms of the fly D. melanogaster. In particular, they revealed the ability of this snoRNA to dramatically increase the lifespan of flies by halting the mechanisms of aging and fighting against the associated deleterious effects. jouvence would thus make it possible to fight against diseases associated with old age such as neurodegeneration, intestinal hyperplasia, but also against metabolic disorders, while prolonging the lifespan of the organism. This snoRNA appears to be involved in various metabolic pathways that may impact on long-term health of fruit flies. jouvence appears to regulate lipid metabolism, intestinal homeostasis, and stress resistance. On the other hand, its inactivation causes adverse effects that lead to the rapid degradation of several metabolic functions and premature death of flies. The results obtained in this study reveal a link between youthfulness and the control of healthy aging in D. melanogaster
Ducastel, Sarah. "Le récepteur nucléaire FXR dans les cellules L entéroendocrines : régulateur de la réponse aux acides gras à chaîne courte, métabolites du microbiote intestinal." Thesis, Lille 2, 2019. http://www.theses.fr/2019LIL2S022.
The control of glucose homeostasis is the result of a close dialogue between the different metabolic organs through nervous and hormonal messages. Among the regulatory mechanisms, the incretin GLP-1 (Glucagon-Like Peptide-1), produced and secreted by enteroendocrine L cells in the intestine in response to food intake, enhances insulin secretion by the pancreas. At the beginning of mythesis, we have shown first that activation of the nuclear Farnesoid X Receptor (FXR) decreases theproduction and the secretion of GLP-1 in response to glucose. However, there are many other stimuli ofGLP-1 secretion. In particular, the intestinal microbiota participates in the control of energy homeostasisby fermentation of dietary fibers, producing short chain fatty acids (SCFAs) in the colon which promotethe secretion of the incretin GLP-1 by binding to their transmembrane receptors FFAR2 and FFAR3 inenteroendocrine L cells. We therefore investigated whether FXR could also regulate other GLP-1secretion pathways in L cell and the aim of my thesis work was then to study the role of FXR in colonicL cell response to SCFAs.GLP-1 secretion in response to SCFAs was evaluated ex vivo in intestinal biopsies from micetreated with GW4064, a synthetic agonist of FXR, in murine colonoids from WT and FXR KO mice, invitro in murine L cells GLUTag and human L cells NCI-H716 activated with GW4064 and in vivo inWT and FXR KO mice after supplementation with prebiotics (inulin type fructans) to increase SCFAsproduction in the colon. Expression of the SCFAs receptors FFAR2 and FFAR3 were also examined inthese different models and FFAR2 Gαq-signalling pathway was evaluated in vitro.SCFA-induced GLP-1 secretion is blunted in colon explants from mice treated with GW4064 and improved in FXR KO colonoids. In vitro activation of FXR inhibits GLP-1 secretion in response toSCFAs and synthetic ligands of FFAR2, mainly by decreasing FFAR2 expression and FFAR2 Gαqsignallingpathway. FXR KO mice exhibit an increased FFAR2 expression in colon and increased plasma GLP-1 levels after prebiotic supplementation.Overall my thesis results show that FXR inhibition increases GLP-1 secretion byenteroendocrine L cells in response to glucose and to gut microbiota-metabolites, the SCFAs. Thecombination of FXR antagonists with prebiotic supplementation can thus be a promising therapeuticapproach to stimulate the incretin axis in the treatment of type 2 diabetes and non-alcoholic fatty liverdiseases such as NASH (Non-Alcoholic SteatoHepatitis)
Paillet, Juliette. "Le lien entre auto-immunité et immunosurveillance des cancers dans le cas des cholangites et du cholangiocarcinome." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASL009.
Bile duct cancer or cholangiocarcinoma (CCA) is the second most common primary liver tumor. The arsenal of treatments for CCA is highly limited due to the resistance to standard chemoradiotherapies and to the low resection efficiency. Chronic inflammation is a well-known risk factor for cancer development, and two chronic inflammatory diseases of the bile ducts are characterized: primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC). Hence, PSC is the 1st etiology established of CCA in Western countries. In contrast, patients with PBC never develop CCA. Based on this observation, we hypothesized that PBC- associated autoimmunity would fuel CCA immunosurveillance and protect the patients from its emergence. In our mouse models, we observed that PBC reduced the frequency of tumor onset and delayed the tumor growth kinetic. Conversely, PSC did not impact the progression of the CCA. We demonstrated that this protection was CCA-specific and did not have any effects on others tumor histotypes. It was also dependent on CD4+ and CD8+ T lymphocytes, B cells, and especially dependent on the IFNγ-mediated response. Altogether, these results evidence a mechanistic overlapping between autoimmunity and cancer immunosurveillance, with autoimmune reactions against organ-specific self-antigens contributing to the elimination of malignant cells originating from the same tissue
Bauvin, Pierre. "Modélisation de la stéatose hépatique (NAFLD) et de ses facteurs de risque par apprentissage sur des données de santé." Thesis, Lille 2, 2020. http://www.theses.fr/2020LIL2S028.
Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease which is a combination of simple, slowly progressing steatosis, and non-alcoholic steatohepatitis (NASH), an inflammatory form which accelerates its progression. It is estimated that one in four people in the world is affected by NAFLD, and its prevalence is increasing rapidly, in parallel with the prevalence of its main risk factors: overweight, obesity and type 2 diabetes.This pathology is asymptomatic up to the complications, cirrhosis and liver cancer (hepatocellular carcinoma, HCC), which leads to late diagnosis and a negative impact on the associated morbidity and mortality. Furthermore, the reference diagnosis requires a liver biopsy, an invasive examination that cannot be performed routinely. As a result, the progression of the disease is poorly known and its estimation may suffer from a selection bias, towards patients with significant risk factors, who require a biopsy in the first place. A better understanding would allow the implementation of strategies to reduce its burden.The modelling approach is appropriate to take into account all susceptible patients, without having to carry out a large-scale follow-up study using liver biopsies in patients who are mostly asymptomatic. The objectives of this thesis are to describe and quantify the progression of NAFLD, to predict the associated morbidity and mortality, and to identify the population at risk, using Markov models. To do this, it is necessary to fill in some of the progression parameters via a literature review, to characterise the initial states (population likely to develop NAFLD) and the final states (mortality due to NAFLD), in order to deduce the missing progression parameters between the onset of the disease and mortality, by back-calculation.To exhaustively characterise NAFLD mortality, we identified all patients with cirrhosis or HCC from national hospital databases, representing more than 380,000 patients. We then developed an identification algorithm to determine the etiology underlying the hepatic complication, based on all the stays of the identified patients. This algorithm requires the identification of patients with cirrhosis or HCC of alcoholic or viral origin, to obtain by elimination only NAFLD patients. Once the specific mortality data had been obtained, we estimated the population likely to develop NAFLD, defined as all individuals with overweight or type 2 diabetes, excluding the population of excessive drinkers. We estimated the prevalence and incidence of this population, and modelled its evolution with age and years, based on individual data from surveys representative of the French population.Finally, we quantified the progression of NAFLD, and the impact of risk factors, using two approaches: from the literature, and from biopsy data from more than 1,800 obese patients who were candidates for bariatric surgery, resulting in a tool for predicting the progression of NAFLD in this population. We chose to back-calculate the progression parameters corresponding to the asymptomatic states, which are the most susceptible to selection bias.We obtained a model of the progression of NAFLD, taking into account the dynamic distribution of the population among weight classes and diabetes status, and resulting in the observed statistics of NAFLD deaths. The model takes into account gender, age, year, BMI (body mass index) class, diabetes status and the presence of a genetic polymorphism (PNPLA3 rs738409, C→G) as covariates of progression. It is a tool for assessing the impact of a possible treatment or public health policy on morbidity and mortality
Schmitt, Romain. "S-nitrosoglutathion et perméabilité intestinale : de la mise en place d’un modèle de chambre de Ussing à l’étude de l’impact de ce donneur de monoxyde d’azote sur la barrière intestinale Involved factors in the maintenance of intestinal barrier homeostasis: a review How to guarantee results from ex vivo studies based on Ussing chamber system for studying intestinal barrier integrity and function Comparison between two derivatization methods of nitrite ion labeled with 15N applied to liquid chromatography-tandem mass spectrometry Influence of S-nitrosoglutathione metabolism on its intestinal permeability Luminal S-nitrosoglutathione effects on intestinal barrier in an ex vivo model of Ussing chamber." Thesis, Université de Lorraine, 2019. http://www.theses.fr/2019LORR0342.
Nitric oxide is known for its many actions to maintain intestinal barrier homeostasis, regulating mucus secretion, oxidative stress, immune system… S-nitrosoglutathione (GSNO), a nitric oxide donor naturally produced by the organism, has shown a beneficial effect on the intestinal barrier reinforcement. Nowadays, challenge is to understand the mechanisms inherent to this observation. For that, a Ussing chamber study was performed. After the model validation, by following permeability markers, histological studies, and cell junction proteins expression study, the GSNO metabolism administered in the intestinal lumen was explored. Also, GSNO effect on the intestinal barrier permeability was evaluated. Results allow today to consider GSNO as an interesting and promising drug candidate, in the context of intestinal, cardiovascular or cerebral pathologies
Addi, Mohamed. "Caractérisation fonctionnelle d'une beta-xylosidase de lin (Linum usitatissimum L.) : rôle(s) potentiel(s) dans le métabolisme pariétal." Thesis, Lille 1, 2008. http://www.theses.fr/2008LIL10097/document.
Flax (Linum usitatissimum) has been a source of high quality fibers (bast fibers) for several thousand years. The fibers are currently used in the textile industry but also increasingly in the fabrication of composites. The interesting mechanical properties of these bast fibers depend upon the structure and chemical composition of their cell walls. ln order to improve our knowledge about the mechanisms underlying cell wall formation in flax fibers we produced ESTs from outer tissues, rich in fibers. Functional classification of ESTs allowed the identification of sequences coding a potential beta-xylosidase (LuBXL1). LuBXL1 down-regulated (IR-PTGS) plants did not show any visible phenotype. However, microscopie analysis suggested that down-regulation could have affected xylem cell wall structure. Enzymatic Fingerprinting indicated a relative increase in the relative quantity of the XXXG oligoxyloglucans in stem inner tissues of down-regulated lines, together with a relative decrease in the quantity of certain oligoxylans. These observations suggest that the down-regulation of LuBXL1 in flax is associated with modifications in cell wall hemicelluloses
Buis, Alexia. "Les cœlomocytes régulent le métabolisme lipidique intestinal et l’extension de la durée de vie en réponse à la restriction alimentaire à travers la lipase LIPL-5 chez Caenorhabditis elegans." Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEP033.
Lifespan of a great number of animal models can be lengthened by direct interventions such as genetic mutations, pharmacological treatments or caloric restriction (CR). In this thesis, we have used the model organism Caenorhabditis elegans to study the impact of a drastic reduction in daily food intake without malnutrition (CR) on lifespan. Our data show that CR mediated lifespan increase is significantly greater in sterile animals than in fertile animals. In addition, sterile animals harbor slow lipid catabolism under CR conditions. We show that, in wild-type fertile animals, CR induces the lipase LIPL-5 that limits lifespan and accelerates lipid catabolism. In sterile animals, CR no longer increases LIPL-5 expression, lifespan is enhanced and lipid catabolism is slowed down. LIPL-5 localizes in the lysosomes of coelomocytes. Interestingly, much like lipl-5 mutants, coelomocyte-deficient animals exhibit reduced lipid catabolism in the gut and extended lifespan upon CR. Finally, sterile animals deficient for coelomocytes no longer exhibit an exacerbated response to CR. Taken together, our results suggest that coelomocytes may integrate environmental signals such as nutrition and regulate important processes such as lipid metabolism, reproduction and longevity. LIPL-5 seems to play an important role in this integration
Magliarelli, Helena. "Uncovering ubiquitylation pathways in liver metabolism by a proteomic approach." Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAJ083/document.
In vertebrates, the liver has developed to be a major metabolic organ able to control glucose and lipid homeostasis. It activates or inhibits specific pathways in a regulated manner, depending on the metabolic state of our organism. Based on the emerging experimental evidence suggesting that the ubiquitin conjugation system is engaged in response to different metabolic cues, we conducted a global proteomic analysis to identify metabolic pathways modified by ubiquitylation. To this end, we used livers of mice subjected to a fasting – refeeding protocol. Amongst the 117 proteins differentially ubiquitylated upon fasting or refeeding conditions, we identified complement 3 (C3) to be ubiquitinated in livers of refed mice. We observed that an activation product of C3, C3a, is ubiquitylated in primary hepatocytes treated with nutrient-rich media. Thus, we suggest that the ubiquitylation of C3 plays a role in the regulation of inflammatory or metabolic functions of C3 in the liver
Pétrault, Maud. "Influence des facteurs de risque vasculaire sur l’apparition et la toxicité des microhémorragies cérébrales." Thesis, Lille 2, 2019. http://www.theses.fr/2019LIL2S011/document.
Cerebral microhemorrhages (CMH) are characterized by the rupture of small intracerebral vessels, leading to blood effusions with a diameter of less than 5 mm in Humans, and considered as asymptomatic. Despite their microscopic size and their silent nature, they are increasingly taken into account by clinicians because they can reflect a vascular fragility and the severity of underlying neurovascular diseases. Their toxicity to the brain tissue is often speculated but has never been demonstrated, raising doubt about their potential impact on the onset or on the evolution of cognitive decline. Moreover, it is difficult to know the specific effects of CMH because they are often associated with a pathology whose characteristics influence the results observed. In this context, we have developed a new method of induction of disseminated CMH in healthy mice. In addition to investigate the histological and behavioral impact of these lesions in the short and in the long term, we assessed the influence of vascular risk factors (through oral anticoagulant treatments) and metabolic disorders (through a high fat diet) on their severity. Our investigations demonstrate that the presence of disseminated CMH in a healthy context induce a progressive impairment of visual recognition memory in mice. The addition of an oral anticoagulant treatment increases the severity of the lesions but they remain silent in the short term, except for the warfarin which provokes fatal hemorrhagic transformations. Similarly, the presence of metabolic disorders has little impact on the severity of microhemorrhagic burdens. In any case, the presence of CMH does not precipitate or aggravate the long-term cognitive decline. Thus, vascular and metabolic risk factors do not appear to have a direct influence on CMH-induced toxicity in a context of non-neurodegenerative cognitive impairment
Bouillier, Camille. "L'analyse de l'interactome du facteur de transcription M2-1 du Virus Respiratoire Syncytial révèle une interaction avec PABPC1 (polyA-binding protein cytoplasmic 1)." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLV010/document.
Although the Respiratory Syncytial Virus, responsible of bronchiolitis in infants, represents a major public health problem, there are currently no vaccine or curative antiviral directed against it. The lack of information on key steps of its viral cycle and on virus-cell interactions hinders the development of new antiviral molecules.We chose to study the interactome of two viral proteins: the polymerase L and the transcription factor M2-1. To do so, we developed a screen based on interactomic and functional criteria.The first step consisted in identifying potential binding partners of M2-1 and L by co-immunoprecipitations coupled to quantitative proteomics. For better relevance, this screen was realised on infected cells, thanks to recombinant viruses produced by reverse genetics. 45 and 137 potential binding partners of M2-1 and L respectively were thus identified. A systematic study of the inhibition of 15 potential partners of M2-1 and its impact on viral multiplication enabled the selection of three candidates: ILF2, PABPN1 and PABPC1.We chose to concentrate on PABPC1. The inhibition of PABPC1’s expression reduces viral multiplication, but no specific effect on viral transcription or translation was brought to light. Its interaction with M2-1 was confirmed, and the MLLE domain of PABPC1 was identified as the M2-1 binding site. The interaction between M2-1 and PABPC1 was observed both in the cytoplasm and in IBAGs, substructures of viral inclusion bodies where viral mRNA accumulate. We formulated the hypothesis that M2-1, with PABPC1, stays with viral mRNA after leaving inclusion bodies and during their translation. This suggests a role for M2-1 in the fate of viral mRNA downstream of transcription
Moya, Plana Antoine. "Recherche de biomarqueurs pronostiques dans le mélanome muqueux non opérable et/ou métastatique : Régulation traductionnelle de SOX10 par l’hexokinase 2 et modulation de l'agressivité tumorale dans le mélanome cutané Prognostic Value and Therapeutic Implications of Nodal Involvement in Head and Neck Mucosal Melanoma Evaluation of the Efficacy of Immunotherapy for Non-Resectable Mucosal Melanoma Oncologic Outcomes, Prognostic Factor Analysis and Therapeutic Algorithm Evaluation of Head and Neck Mucosal Melanomas in France Mélanomes cutanés cervico-faciaux Prognostic 18F-FDG PET Biomarkers in Metastatic Mucosal and Cutaneous Melanoma Treated with Immune Checkpoint Inhibitors Targeting PD-1 and CTLA-4." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASS069.
Mucosal melanoma is a rare tumor with a high metastatic potential. Immunotherapy has promising results in this aggressive subtype of melanoma. In a cohort of 23 patients with non-resectable and/or metastatic mucosal melanoma who received anti-PD1 immunotherapy, we showed that the activation of the eukaryotic translation initiation complex, eIF4F, was a strong prognostic biomarker of response. This activation was assessed with a proximity ligation assay between eIF4E and eIF4G. The other biomarkers, such as the PD-L1 tumoral expression or the characteristics of tumor-infiltrating lymphocytes, had no prognostic value in this cohort.Aerobic glycolysis is usually the main metabolic pathway in tumor cells during cancerogenesis. This specificprocess is called “Warburg effect”. During melanomagenesis, we observed a positive correlation between the expression level of hexokinase 2 (HK2, first enzyme of glycolysis) and the tumor invasiveness. In this study, we showed that inhibition of HK2 expression (by siRNA) induced, in vitro, a major decrease of migration and invasion potential independently of the basal glycolytic metabolism or HK2 expression level in the cell lines. Moreover, performing a polysome profiling analysis, we demonstrated that HK2 was regulating the translation of SOX10 mRNA, a transcription factor involved in initiation and progression of melanoma. We, then, realized an RNA immunoprecipitation in formaldehyde and showed that HK2 was an RNA-binding protein, able to interact with the SOX10 mRNA
Payen, Cyrielle. "Implication des troubles métaboliques maternels sur la programmation fœtale des fonctions métabolique hépatique et vasculaire de la descendance." Thesis, Angers, 2019. http://www.theses.fr/2019ANGE0047.
In utero exposure to maternal metabolic pathologies leads to fetal programming, which increases the occurrence of metabolic, vascular and hepatic diseases in offspring. In this thesis, we focused on fetal programming induced by two types of maternal metabolic dysfunctions : obesity and diabetes. We highlighted that maternal obesity induced direct fetal programming of the vascular function in offspring regardless of metabolic disorders. In addition, we showed that disruption of perinatal nutrition leads to the early occurrence of metabolic disorders in offspring of obese mothers, without modifying the fetal programming of vascular function. Bariatric surgery doesn’t seem tobe able to reverse fetal programming of metabolic and vascular functions as described in obese mothers offspring. We also showed that fetal programming of vascular dysfunction of diabetic mother’s offspring can be transmitted from the F1 to the F2 generation. Finally, we highlighted the importance of sexual dimorphism in the fetal programming of vascular function. These results demonstrate that vascular (arterial hypertension) and metabolic (obesity, diabetes) diseases are not exclusively behavioral diseases but can also have a fetal life origin. They can be transmitted over several generations, thus contributing to explain the worldwide spread of obesity and associated metabolic disorders
Faid, Valegh. "Approches de glycomique appliquées à l'étude des pathologies métaboliques des glycoprotéines." Thesis, Lille 1, 2008. http://www.theses.fr/2008LIL10153/document.
Glycoprotein-derived glycans are involved in numerous biological processes , such as inflammation, immunity. development and reproduction. They are responsible for numerrous physicochemical, immunological and biological properties of glycoproteins, and, they can modulate the pharmacological properties of therapeutic recombinant glycoproteins. Their importance has been demonstrated by the severity of the clinical pictures and the high level of morbidity and mortality of patients suffering from congenital disorders of glycosylatlon (COG). Therefore, in the field of clinical chemistry, there is a lack of glycobioanalytica! tools for the exploration of the glycoprotein-derived glycan metabolism. Then, the objectives of our thesis was founded on the development of glycobioanalytical approaches, relied on mass spectrometry, applied to the study of the glycosylation of biologically interesting glycoproteins, such as LAMAN, or biological fluids, such as blood plasma and urine, known to contain numerous specific diagnostic and/or prognostic glycobiomarkers, yielded during congenital defect in the biosynthesis (CDG) and in the catabolism (glycoproteinoses) of glycoprotein-derived glycans. The first step of our thesis consisted in the site-specifie glycosylation analysis of bovine LAMAN, whlch constltutes our model of study of the human enzyme and of the molecular pathogenesis of a-mannosidosis. The detailed structures as well as their distribution within six of eight glycosy!ation:sites were determined. These results constitute a solid basis of work for the site-specific glycosylation analysis of the human recombinant LAMAN, in order to evaluate its therapeutic efficiency in the experimental treatment of a-mannosidosis. The second step of our thesis consisted in the elaboration of mass spectrometry methodologies for the profiling as well as the structural characterization of ths urinary oligosaccharides an glycoasparagmes, as valuable glycoprotemoses-assoclated glycobiomarkers. Applled to the mass profilinïg of urinary oligosaccharides of a patient suffering from ß-mannosidosis, nine new structures, never described in man, were identified and partially characterized. Finally, the last part of our thesis consisted in the elaboration of a global glycobloanalytlcal methodology, enablrng the exploratIon of g/ycosylation prccesses of cellular proteins. ln this study we described a.rapid mass spectrometric strategy for the structural characterization of N- and O-glycan chams ln the dlagnosis of genetlc defects in glycan blosynthesis. Applied to patients suffering from CDG-lla and CDG-llg ,valuable diagnostic glycobiomarkers were identified
Anthierens, Agathe. "Réponses hémodynamiques et métaboliques des muscles paravertébraux à l'exercice : influence de la lombalgie chronique et de la pratique d'activités physiques." Thesis, Lille, 2019. http://www.theses.fr/2019LIL2S009.
Introduction: Paraspinal muscles are required continuously during daily tasks for trunk stabilization and mobilization. For this, aerobic metabolism muscle contribution is required. Chronic low back pain is characterized by a high level of fatigability and pain sensations in regard to paraspinal muscles. These symptoms may be attributed to an alteration in aerobic metabolism responses. Conversely, practising physical and sports activities (PSA) could improve these responses.Objective: The main objective was to determine the specificities in aerobic metabolism responses in regard to paraspinal muscles, in chronic low back pain patients following a functional restoration program and in healthy athletes.Method: Four studies have been conducted. Participants performed submaximal trunk extension exercises on an isokinetic dynamometer for five minutes, to assess paraspinal muscle aerobic metabolism responses to exercises. Chronic low back pain patients were paired with and compared to healthy individuals and followed during a functional restoration program, in which physical exercise was the main component. Also, healthy young individuals, with and without sport specialization, were compared with each other.Results/Conclusion: In chronic low back pain patients, the functional restoration program allows an acceleration in V̇O2, kinetics, an increase in paraspinal muscle oxygenation, and an increase in mechanical efficiency to exercise. In young athletes, the aerobic responses were also improved, and the changes in responses depended on the training modalities. Practicing SPA enhances the aerobic metabolism contribution during prolonged trunk extension exercise, in regard to paraspinal muscles. There was no difference in aerobic metabolism responses between the chronic low back pain patients and the healthy individuals, despite weak levels of maximal strength and high levels of muscle fatigability when exercising (for the chronic low back pain patients). Although the preliminary results did not attest to an alteration in aerobic responses in chronic low back pain patients, our results suggest that practising physical activities could limit paraspinal muscle fatigability, which could be a way to prevent injury and disappointing performances, by improving aerobic metabolism responses to exercise
Perrin, Florent. "Modification du métabolisme des caroténoïdes en réponse aux stress biotique et abiotique chez la carotte." Thesis, Angers, 2016. http://www.theses.fr/2016ANGE0027/document.
Carrot presents a high nutritional interest as a carotenoid intake source. However, knowledge about accumulation mechanisms of these compounds is a major issue. While genetic determinism was relatively well studied, the impact of stresses on carotenoid accumulation in carrot remains unknown. This thesis work aims to determine (i) the impact of biotic and abiotic stresses applied individually or in combination on carotenoid contents in carrot leaves and roots, (ii) the regulation mechanisms which could explainthese variations and (iii) if secondary metabolism is specifically affected independently from primarymetabolism. Results bring to light a negative effect of the different stress conditions, particularly applied in combination, on carotenoid contents in carrot leaves and roots but depend on genotypes. Transcriptional regulation based on carotenoid biosynthetic genes can only partially explain contentvariations. Chlorophyll content variations in leaves and sugar content variations in roots are correlated to those of carotenoids suggesting common regulation mechanisms. This work shows that the impact of stress on culture, and particularly in combination, is an important determinism of nutritional quality. Further works need to be performed to establish a more precise regulation network pattern of carotenoid accumulation in carrot
Adam, Clément. "Impact de l’acétoacétate sur la biologie des macrophages humains : analyse phénotypique et métabolique The roles of CSF s on the functional polarization of tumor‐associated macrophages." Thesis, Angers, 2019. http://www.theses.fr/2019ANGE0049.
In case of inflammation or injury, macrophages must adapt and function in a hostile environment, such as an acidic environment. Indeed, excessive production and local accumulation of lactic acid, is a characteristic of inflammatory process and tissue damage. Currently, the metabolic adaptation of human monocytes and macrophages to acidosis and the nature of the factors that enable them to acquire a repair profile are poorly understood. In this study, we show that monocytes differentiated in vitro into macrophages in the presence of the acetoacetate, aketone body produced by the liver, show an increase in oxidative phosphorylation associated with the acquisition of a pronounced repair profile. In addition, ketone bodies and acetoacetate accelerate the rate of healing in an in vivo healing model. From a mechanistic point of view, monocytes differentiated into lactic acidosis accumulate depolarized mitochondria and show signs of mitophagy as well as a significant reduction in nutrient absorption making their survival dependent on autophagy. Interestingly, acetoacetate prevents the consequences of acid stress (maintaining integrity and mitochondrial function), allowing cells to survive without resorting to autophagy. Acetoacetate therefore appears as a unique metabolite to improve the tolerance of cells and tissues to damage induced by acidosis and a local factor promoting the generation of macrophages with a repair profile
Zeitler, Alexandre. "Traitement d'une douleur neuropathique par la modulation pharmacologique du complexe basolatéral de l'amygdale." Thesis, Strasbourg, 2013. http://www.theses.fr/2013STRAJ115/document.
The amygdala is a major control center of the emotions, but also integrates sensory, especially nociceptive information. Cortical afferents to the amygdala largely target its basolateral complex. The basolateral amygdala (BLA) then projects to the central amygdala nucleus, which in turn projects densely to the periaqueductal gray and thus can drive a behavioural output via the spinal cord. Data obtained during my thesis have shown that the balance between excitation and inhibition in the BLA triggers an tonic control of pain. Therefore modulating one of the neurotransmission directly influences the pain threshold of control or nociceptive mice. My thesis work also focused on the functioning of an anxiolytic and non benzodiazepinic drug ; Etifoxin (EFX). This molecule as a positive modulator of GABAA receptors and indirectly by increasing the synthesis of neurosteroids, also known as strong modulator of these receptors. In our team, we already showed that EFX has anti-nociceptive effects when injected intraperitonealy in rats. Here we wanted to determine the action of EFX on pain descending control drive by BLA. We showed that EFX infusion in the BLA seems to be anti-nociceptive, inducing a recover of the pre-cuff mechanical threshold level. We also used a patch-clamp approach to study directly in vitro the modulation of the inhibitory synaptic transmission produced by EFX. We showed that EFX potentiate the inhibition in BLA neurons via different and complementary mechanisms. These potentiating effects are mostly dependent of a neurosteroidogenesis increase
Wang, Qili. "Interaction entre la sous unité V0 de la V-ATPase et le facteur d'échange ARNO et son implication fonctionnelle dans l'exocytose régulée." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAJ049.
Lipids play key cellular functions and are involved in many human diseases and little information is available on their exact function. This is especially the case in neurosecretion that relies on the fusion of specific membrane organelle with the plasma membrane for which relatively little attention has been paid to the necessary role of lipids. Recent studies have established the importance of lipid compartmentalization at the exocytotic sites and validated the contribution of fusogenic lipids such as phosphatidic acid (PA) for membrane fusion. The V-ATPase is involved both in the charging of secretory vesicle and the membrane fusion for secretion of vesicle. Indeed, the V1 and V0 subdomains were shown to dissociate during stimulation allowing subunits of the vesicular V0 to interact with different proteins of the secretory machinery. We show here that V0a1 interacts with the exchange factor ARNO and promotes Arf6 activation during exocytosis in neuroendocrine cells. Interfering with the V0a1-ARNO interaction prevented phospholipase D (PLD) activation, phosphatidic acid synthesis during exocytosis, and altered the kinetic parameters of individual fusion events.We suggest that V1 dissociation from V0 could represent the signal that triggers the activation of the ARNO-Arf6-PLD1 pathway and promotes PA synthesis needed for efficient exocytosis in neuroendocrine cells
Landureau, Maud. "Développement d'outils thérapeutiques ciblant les agrégats d'alpha-synucléine dans les synucléinopathies Mapping of Three Alpha-Synuclein Fibrillar Polymorphs Surfaces Internalization and Degradation of Different Alpha-Synuclein Strains by Neurons or Astrocytes." Thesis, université Paris-Saclay, 2021. http://www.theses.fr/2021UPASL022.
The aggregation of alpha-synuclein and the spread of aggregates from neuron to neuron have been consistently shown to be at the heart of the pathophysiological process of devasting neurodegenerative diseases like Parkinson's disease, dementia with Lewy bodies or multiple system atrophy. While fibrillar alpha-synuclein rich deposits are a common hallmark of synucleinopathies, distinct pathological phenotypes are observed. We hypothesize that different "strains" of fibrillar alpha-synuclein with different affinity/tropism, internalization and seeding properties, may account for the patho-physiological and clinical heterogeneity in Parkinson's disease and other synucleinopathies. We aim to determine a way to interfere with the binding to neurons of distinct alpha-synuclein assemblies and their prion-like propagation. To this end, we mapped the surface of three distinct alpha-synuclein strains. First, we implemented limited proteolysis and hydrogene-deuterium approaches combined to mass spectrometry in order to map, in vitro, the solvent exposed-surfaces of fibrillar alpha-synuclein assemblies generated in vitro. Second, we studied the processing of different alpha-synuclein strains using primary cultures of neurons and astrocytes in order to analyze the strain degradation characteristics in cellulo, related to the surface specificities determined in vitro. Mapping the surfaces of those assemblies and identification of exposed and protected strain-specific sequences open the way, in the long term, for developing highly specific binders that might either detect specific alpha-synuclein strains or inhibit cell-to-cell propagation disease progression
Colin, Florent. "Caractérisation du rôle de la frataxine dans la machinerie de biosynthèse des clusters FeS et développement d'un logiciel de prédiction des protéines FeS." Thesis, Strasbourg, 2013. http://www.theses.fr/2013STRAJ113/document.
Friedreich Ataxia (FA) is the most prevalent form of autosomal recessive ataxia in the Caucasian population. Frataxin is implicated in the biosynthesis of iron-sulfur (FeS). The first axis of my work was to better characterize the function of Frataxin in the “early” complex of FeS clusters biosynthesis (NFS1/ISD11/ISCU). I was able to show the crucial involvement of Frataxin in the control of iron entry in this complex, on the enzymatic activity of NFS1 and on the transfert of FeS cluster to apo-proteins. Thesecond axis was the development of a bio-informatic software (PredISC) that is able to predict potential iron-sulfur containing proteins. The software allows us to generate a list of candidates that will be compiled in a database. In the future transversal approaches have to be associated in order to reduced the number of candidates, and increase their interest
Greco, Marion. "Synthèse de dérivés de la Névirapine substitués au carbone 13 pour l’étude de l’activation métabolique de cet antirétroviral dans des épidermes humains reconstruits." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAF009/document.
Drug-induced toxidermia are cutaneous toxicity reactions caused by a drug therapy. In the most serious cases, these side effects of drugs are life-threatening.Most toxidermia are not induced by the parent drug, but by one or several skin metabolite(s) which may become antigenic by binding with epidermal proteins. This drug-protein conjugation step could be the starting point of immune responses leading to skin lesions.The aim of the PhD project was to study the in situ metabolic activation of Nevirapine, an anti-retroviral drug associated with toxidermia with an incidence of 20%. By using a non-invasive analysis technique, HR-MAS NMR spectroscopy on reconstructed human epidermis, it has been possible to follow the possible bioactivation of Nevirapine and its derivatives as well as the binding of one of them with the epidermis
Bezine, Maryem. "Implication du canal potassium Kv3.1 dans la lipotoxicité du 7-cétocholestérol, 24S-hydroxycholestérol et de l’acide tétracosanoïque sur des cellules nerveuses 158N et BV-2 : Etude des relations entre Kv3.1, homéostasie potassique et métabolisme peroxysomal dans la maladie d’Alzheimer." Thesis, Bourgogne Franche-Comté, 2017. http://www.theses.fr/2017UBFCI010/document.
Potassium (K+) is involved in the regulation of cellular excitability, cell cycle regulation, cell viability, neuroprotection and maintenance of microglial and oligodendrocytic functions. Potassium dysfunction, described in several neurodegenerative diseases such as Alzheimer's Disease (AD), multiple sclerosis (MS), Parkinson's disease and Huntington's disease, may be a potential therapeutic target. The underlying toxic mechanisms of these neurodegenerative pathologies involve oxysterols, which are oxidized cholesterol derivatives, and fatty acids including those associated with peroxisomal metabolism. 7-ketocholesterol (7KC), 24S-hydroxycholesterol (24S-OHC) and tetracosanoic acid (C24:0), often found at increased levels in the brain and plasma of patients with neurodegenerative diseases (Nieman-Pick disease, MS, Parkinson's disease, Huntington's disease and X-ALD) lead to a breakdown of the redox equilibrium leading to neurodegeneration. In this context, it is interesting to determine the possible connection between the lipid environment and potassium homeostasis The in vitro study was carried out on 158N murine oligodendrocytes and microglial BV-2 cells. We have shown that the lipotoxicity of 7KC, 24S-OHC and C24:0 implies retention of K+ involving the voltage dependent potassium channels (Kv). These results have shown that inhibition of Kv channels lead to an increase in [K +] i contributing to the cytotoxicity of 7KC, 24S-OHC and C24:0. The retention of K+ induced by oxysterols (7KC and 24S-OHC) would be under the control of Kv3.1b. A clinical study, on plasma of patients with Alzheimer’s disease, revealed a negative correlation between docosahexaenoic acid (DHA) and K+ concentration. In the J20 mice, a transgenic model of Alzheimer’s disease, the expression of Kv3.1b and Abcd3 was decreased in the hippocampus and cortex. Overall, the results obtained established relationships between lipotoxicity, peroxisomal metabolism and potassium homeostasis in neurodegeneration and suggest a possible modulation of the expression and activity of kv3.1b in the pathophysiology of neurodegenerative diseases. So, modulation of Kv3.1 could constitute a new therapeuthic approach against some neurodegenerative diseases