No description available.

Le syndrome de détresse respiratoire aiguë (SDRA) est une forme sévère de défaillance respiratoire qui se caractérise par la présence de dommages alvéolaires, d’un oedème pulmonaire et d’une réponse inflammatoire exacerbée. C’est une condition pour laquelle il n’existe à ce jour aucun traitement pharmacologique efficace. Lors des dernières années, des antagonistes des récepteurs de l’IL-1 (Kineret) et de l’IL-6 (tocilizumab) ont fait preuve d’une efficacité modérée pour le traitement du SDRA causé par la COVID-19. Cependant, leur potentiel thérapeutique en SDRA clinique non causé par la COVID reste à démontrer et les résultats obtenus dans les modèles animaux sont mitigés. Nous avons émis l’hypothèse que le tocilizumab et le Kineret pourraient améliorer la résolution des différents paramètres du SDRA non causé par la COVID-19. Nous avons aussi posé l’hypothèse que des peptides, antagonistes des récepteurs de l’IL-1 (rytvela) ou de l’IL- 6 (HSJ633) et permettant de préserver certaines voies aux propriétés cytoprotectrices en aval de ces récepteurs, pourraient potentiellement être plus efficaces que le Kineret et le tocilizumab pour le traitement des paramètres du SDRA. L’objectif de ma maîtrise était donc de tester ces deux hypothèses dans un modèle murin d’atteinte pulmonaire aiguë (ALI) induite par la bléomycine, qui mime pendant sa phase aiguë les principaux paramètres du SDRA. Mes travaux montrent qu’aucun des quatre antagonistes n’a permis d’améliorer significativement les paramètres observés à jour 7 post-bléomycine (état général, dommages alvéolaires, oedème et inflammation pulmonaire). Ainsi, mes données suggèrent que dans notre modèle d’ALI induit par la bléomycine, la réponse inflammatoire induite via le IL-1R ou le IL-6R ne semble pas constituer un des mécanismes principaux engendrant les différentes atteintes, puisqu’elles ne sont pas prévenues par les antagonistes de ces récepteurs. En plus de contribuer à mieux comprendre ce modèle animal, mes résultats permettent de mettre en lumière que la réparation des dommages ainsi que la résorption secondaire de l’oedème sont cruciales pour la résolution du SDRA et que de viser seulement la voie inflammatoire est insuffisant. / Acute respiratory distress syndrome (ARDS) is a form of severe lung failure characterized by the presence of a pulmonary edema, an inflammatory response, and alveolar damage. There is currently no effective pharmacological treatment for ARDS. In recent years, IL-1 and IL-6 receptor antagonists Kinerert and tocilizumab, respectively, have shown some efficacy as a treatment of ARDS caused by COVID-19. However, their therapeutic potential in non-COVID ARDS remains to be proven and the results obtained in animal models are conflicting. We thus tested the hypothesis that tocilizumab and Kineret could improve the resolution of key parameters of non-COVID ARDS. We also hypothesized that two peptides, rytvela and HSJ633, IL-1 and IL-6 receptor antagonists, respectively, which preserve some of the cytoprotective downstream pathways, could potentially be more effective than Kineret and tocilizumab in treating the various parameters of ARDS. The goal of my master thesis was therefore to test these two hypotheses in a mouse model of acute lung injury (ALI) induced by bleomycin instillation, which, during its acute phase, mimics the main parameters of ARDS. My work has shown that none of the antagonists were able to significantly improve the parameters observed on day 7 post-bleomycin (general condition of the mice, alveolar damages, pulmonary edema and inflammation). Thus, my data suggest that in our bleomycin-induced ALI model, the inflammatory response triggered via IL-1R or IL-6R does not appear to be the principal mechanism generating the main damaging outcome, since they are not prevented by the antagonists of these receptors. In addition to contributing to a better understanding of this animal model of ALI, my research has highlighted the fact that targeting inflammation alone is insufficient and that repairing alveolar damages, and secondary resorbing lung edema, are cornerstones for the resolution of ARDS.

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Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

L'arthrose (OA) est la maladie musculosquelettique la plus courante. Elle se caractérise par la détérioration progressive du cartilage articulaire, entraînant des douleurs, des raideurs et une réduction de l'amplitude des mouvements. Les mécanismes sous-jacents de l'OA impliquent un déséquilibre physiologique entre la dégradation et la réparation du cartilage, sous l'influence de processus inflammatoires et d'altérations de la structure de la matrice extracellulaire. Le nicotinamide adénine dinucléotide (NAD+) est un cofacteur essentiel impliqué dans de nombreux processus physiologiques, et sa diminution dans l'organisme est associée au vieillissement et à certaines pathologies. Les précurseurs connus du NAD+, tels que la niacine (NA), le nicotinamide (NAM) et le nicotinamide mononucléotide (NMN), suscitent un intérêt croissant dans le domaine de l’OA. La supplémentation en NAD+ a donc le potentiel d'améliorer la santé des articulations, notamment en inhibant l'inflammation et la dégradation. Dans un premier temps, nous avons sélectionné trois précurseurs du NAD+ sur la base de la littérature antérieure et de leur pertinence clinique. Nous avons ensuite étudié l'effet de ces trois précurseurs du NAD+ sur la régulation des protéines dans les processus cataboliques et inflammatoires. Le traitement de chondrocytes primaires avec des concentrations élevées de NA ou de NAM a entraîné une diminution de l'expression des métalloprotéinases matricielles (MMP). En outre, nous avons observé des tendances à la hausse non significatives de l'oxyde nitrique synthase induit (iNOS), après traitement à la NA, et de la cyclooxygenase-2 (COX-2), après traitement au NAM. Le NMN, quant à lui, a produit des résultats contradictoires en termes d'expression protéique, avec une augmentation de l'expression de la MMP et de la COX-2 à une concentration élevée. Suite à ces résultats préliminaires, nous avons voulu connaître les effets du NMN en particulier sur d'autres aspects de la pathogenèse de l’OA. Nous avons donc testé l'effet antioxydant du NMM et de la NA sur la production d'oxyde nitrique (NO) dans des explants de cartilage humain. À notre surprise, nous avons constaté que la NA avait une tendance à la hausse non significative de la production de NO, suivant un schéma similaire à la régulation de la iNOS. En revanche, le NMN avait un effet inhibiteur substantiel sur la synthèse de NO. Nous avons également effectué des tests de prolifération, révélant que le NMN, à des doses élevées, était capable d'augmenter la prolifération des synoviocytes stimulée par l'IL-1β (Interleukine-1beta) in vitro. Nous avons ensuite démontré l'effet du NMN sur la migration cellulaire et la régénération des plaies. Nos résultats ont mis en évidence la capacité du NMN à promouvoir la migration cellulaire à la fois dans les synoviocytes et les chondrocytes, mais surtout dans les chondrocytes dans des conditions normales et inflammatoires. Parallèlement, nous avons montré par des études histologiques que le NMN peut protéger le cartilage articulaire humain de l'érosion induite par l'IL-1β. Nos données fournissent des informations précieuses sur la voie du NAD+ et soulignent sa nouveauté dans les maladies musculosquelettiques telles que l'OA. Bien que nos résultats soulèvent de nombreuses questions, ils laissent entrevoir un effet potentiellement bénéfique de la supplémentation du NAD+ en tant qu'approche thérapeutique ou préventive potentielle de l'OA. / Osteoarthritis (OA) is the most common musculoskeletal disease. It is characterized by the progressive deterioration of articular cartilage, leading to pain, stiffness, and a reduced range of motion. The underlying mechanisms of osteoarthritis involve a physiological imbalance between cartilage degradation and repair, influenced by inflammatory processes and alterations in the structure of the extracellular matrix. Nicotinamide adenine dinucleotide (NAD+) is an essential cofactor involved in many physiological processes, and its depletion in the body is associated with aging and certain pathologies. Known NAD+ precursors, such as Niacin (NA), Nicotinamide (NAM), and Nicotinamide Mononucleotide (NMN), are attracting growing interest in the field of osteoarthritis. Therefore, NAD+ supplementation can potentially improve joint health, notably by inhibiting inflammation and degradation. First, we selected three NAD+ precursors based on previous literature and their clinical relevance. We then investigated the effect of these three NAD+ precursors on protein regulation in catabolic and inflammatory processes. Treatment of primary chondrocytes with high concentrations of NA or NAM resulted in a decrease in Matrix metalloproteinase (MMP) expression. In addition, we observed non-significant upward trends in induced nitric oxide synthase (iNOS), after NA treatment, and cyclooxygenase-2 (COX-2), after NAM treatment. NMN, on the other hand, produced contradictory results in terms of protein expression, with increased MMP and COX-2 expression at a high concentration. Following these preliminary results, we were interested to learn about the effects of NMN in particular on other aspects of osteoarthritis pathogenesis. Thus, we tested the antioxidant effect of NAM and NA on nitric oxide production in human cartilage explants. To our surprise, we found that NA had a non-significant upward trend in NO production, following a similar pattern to iNOS regulation. On the other hand, NMN had a substantial inhibitory effect on NO synthesis. We also performed proliferation assays, revealing that NMN, at high doses, could increase IL-1β (Interleukin-1beta)-stimulated synoviocyte proliferation in vitro. We then demonstrated the effect of NMN on cell migration and wound regeneration. Our results highlighted NMN's ability to promote cell migration in both synoviocytes and chondrocyte cell types, but especially in chondrocytes under normal and inflammatory conditions. In parallel, we have shown through histological studies that NMN can protect human articular cartilage from IL-1β-induced erosion. Our data provide valuable insights into the NAD+ pathway and highlight its novelty in musculoskeletal diseases such as osteoarthritis. Although our results raise many new questions, they point to a possible beneficial effect of NAD+ enhancement as a potential therapeutic or preventive approach to OA.

O desenvolvimento do câncer cervical depende da exposição ao HPV, fator necessário, mas não suficiente. Outras bactérias, tais como ureaplasmas, têm sido associadas como cofatores. O objetivo deste estudo foi avaliar a presença de ureaplasmas em mulheres com lesão cervical, e observar alterações em PHK causadas pela infecção por ureaplasmas. 140 swabs vaginais foram coletados. O material foi submetido a PCR para a detecção de HPV, Mollicutes, U. urealyticum, U. parvum e seus sorotipos, e outras bactérias de importância ginecológica; e qPCR para U. urealyticum e U. parvum. Também foi realizada a infecção de ureaplasmas em PHK transformados com HPV. As células foram contadas e realizou-se a dosagem das citocinas IL1-β, IL-6 e TNF-α. HPV, Mollicutes, U. parvum, sorotipos 1 e 6 de U. parvum, T. vaginalis e G. vaginalis, além de alguns fatores socioeconômicos, foram associados com lesão cervical. Verificou-se maior carga de U. parvum entre mulheres com lesão. Houve diminuição do número de células e maior liberação de IL-6 e TNF-α nos grupos infectados. Com os resultados obtidos neste estudo, foi possível verificar uma associação entre os ureaplasmas e HPV no início das lesões cervicais, contudo mais estudos precisam ser realizados para aprimorar essa hipótese. / The development of cervical cancer depends on the exposure to HPV, necessary factor, but not enough. Other bacteria, such as ureaplasmas, have been associated as cofactors. The aim of this study was to evaluate the presence of ureaplasmas in women with cervical injury, and observe changes in PHK infected by ureaplasmas. 140 vaginal swabs were collected. The material was subjected to PCR for detection of HPV, Mollicutes, Ureaplasma urealyticum, U. parvum (and serotypes) and other bacteria gynecological importance; qPCR for U. urealyticum and U. parvum was made. PHK transformed by HPV was infected by ureaplasma. Cells were counted and it was done titration of IL1-β, IL-6 and TNF-α. HPV, Mollicutes, U. parvum, serotypes 1 and 6 U. parvum, T. vaginalis and G. vaginalis, and some socioeconomic factors were associated with cervical injury. Besides this, it was detected higher load U. parvum among women with injury. There was decrease in cell number and increased release of IL-6 and TNF-α in infected groups. With the results of this study, we found an association among HPV and ureaplasmas at the beginning of cervical lesions, but more studies are needed to enhance this hypothesis.

O desenvolvimento do câncer cervical depende da exposição ao HPV, fator necessário, mas não suficiente. Outras bactérias, tais como ureaplasmas, têm sido associadas como cofatores. O objetivo deste estudo foi avaliar a presença de ureaplasmas em mulheres com lesão cervical, e observar alterações em PHK causadas pela infecção por ureaplasmas. 140 swabs vaginais foram coletados. O material foi submetido a PCR para a detecção de HPV, Mollicutes, U. urealyticum, U. parvum e seus sorotipos, e outras bactérias de importância ginecológica; e qPCR para U. urealyticum e U. parvum. Também foi realizada a infecção de ureaplasmas em PHK transformados com HPV. As células foram contadas e realizou-se a dosagem das citocinas IL1-β, IL-6 e TNF-α. HPV, Mollicutes, U. parvum, sorotipos 1 e 6 de U. parvum, T. vaginalis e G. vaginalis, além de alguns fatores socioeconômicos, foram associados com lesão cervical. Verificou-se maior carga de U. parvum entre mulheres com lesão. Houve diminuição do número de células e maior liberação de IL-6 e TNF-α nos grupos infectados. Com os resultados obtidos neste estudo, foi possível verificar uma associação entre os ureaplasmas e HPV no início das lesões cervicais, contudo mais estudos precisam ser realizados para aprimorar essa hipótese. / The development of cervical cancer depends on the exposure to HPV, necessary factor, but not enough. Other bacteria, such as ureaplasmas, have been associated as cofactors. The aim of this study was to evaluate the presence of ureaplasmas in women with cervical injury, and observe changes in PHK infected by ureaplasmas. 140 vaginal swabs were collected. The material was subjected to PCR for detection of HPV, Mollicutes, Ureaplasma urealyticum, U. parvum (and serotypes) and other bacteria gynecological importance; qPCR for U. urealyticum and U. parvum was made. PHK transformed by HPV was infected by ureaplasma. Cells were counted and it was done titration of IL1-β, IL-6 and TNF-α. HPV, Mollicutes, U. parvum, serotypes 1 and 6 U. parvum, T. vaginalis and G. vaginalis, and some socioeconomic factors were associated with cervical injury. Besides this, it was detected higher load U. parvum among women with injury. There was decrease in cell number and increased release of IL-6 and TNF-α in infected groups. With the results of this study, we found an association among HPV and ureaplasmas at the beginning of cervical lesions, but more studies are needed to enhance this hypothesis.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal