13 research outputs found
A Diet Containing Soybean Oil Heated for Three Hours Increases Adipose Tissue Weight but Decreases Body Weight in C57BL/6 J Mice
Background: Our previous work showed that dietary oxidized linoleic acid given, as a single fatty acid, to LDL receptor knockout mice decreased weight gain as compared to control mice. Other studies have also reported that animals fed oils heated for 24 h or greater showed reduced weight gain. These observations, while important, have limited significance since fried foods in the typical human diet do not contain the extreme levels of oxidized lipids used in these studies. The main goal of this study was to investigate the effects of a diet containing soybean oil heated for 3 h on weight gain and fat pad mass in mice. Additionally, because PPARÎł and UCP-1 mediate adipocyte differentiation and thermogenesis, respectively, the effect of this diet on these proteins was also examined.
Findings: Four to six week old male C57BL/6 J mice were randomly divided into three groups and given either a low fat diet with heated soybean oil (HSO) or unheated soybean oil (USO) or pair fed for 16 weeks. Weight and food intake were monitored and fat pads were harvested upon the studyâs termination. Mice consuming the HSO diet had significantly increased fat pad mass but gained less weight as compared to mice in the USO group despite a similar caloric intake and similar levels of PPARÎł and UCP1.
Conclusion: This is the first study to show that a diet containing soybean oil heated for a short time increases fat mass despite a decreased weight gain in C57BL/6 J mice. The subsequent metabolic consequences of this increased fat mass merits further investigation
Inflammasomes et Ă©pidermolyse bulleuse
National audienceResults Conclusion In this study, we demonstrated that keratinocytes derived from JEB and EBS patients exhibit increased expression of inflammasome components compared to NHEK suggesting a role of inflammasome(s) in EB pathogenesis. Our data highlight the importance of adhesion of the different skin layers to ensure keratinocyte homeostasis. As the dysregulation of inflammasome sensors leads to the excessive production of pro-inflammatory cytokines, it could contribute to the chronic inflammation observed in EB. Further studies on the type of inflammasome(s) implicated in EB and targeted therapeutic interventions to modulate inflammasome activation may hold promise for the development of anti-inflammatory therapies in EB.L'Ă©pidermolyse bulleuse (EB) regroupe un groupe de maladies gĂ©nĂ©tiques rares du tissu conjonctif caractĂ©risĂ©es par une fragilitĂ© de la peau et la formation de phlyctĂšnes en raison de mutations dans les gĂšnes codant pour des protĂ©ines de la membrane basale ou des protĂ©ines modulant l'organisation de la membrane basale. MalgrĂ© la variabilitĂ© phĂ©notypique, toutes les formes d'EB prĂ©sentent des dĂ©fauts de rĂ©paration et de cicatrisation des tissus Ă la suite de traumatismes mineurs entraĂźnant une inflammation locale. Le rĂŽle des cytokines dans l'orchestration de la rĂ©paration et de l'intĂ©gritĂ© des tissus dans l'EB a Ă©tĂ© peu Ă©tudiĂ©. Les infammasomes sont des complexes multiprotĂ©iques qui contrĂŽlent l'activation et la libĂ©ration de cytokines pro-inflammatoires, Ă savoir l'interleukine-1ÎČ (IL-1ÎČ) et l'interleukine-18 (IL-18), par l'intermĂ©diaire de la caspase-1. Notre objectif Ă©tait d'Ă©tudier l'expression des composants de l'inflammasome et la sĂ©crĂ©tion de cytokines dans les kĂ©ratinocytes de patients atteints d'EB et de contrĂŽles.Des kĂ©ratinocytes primaires ont Ă©tĂ© dĂ©rivĂ©s de biopsies de personnes atteintes de diffĂ©rents types d'EB, dont l'Ă©pidermolyse bulleuse jonctionnelle (JEB) (N=4) et l'Ă©pidermolyse bulleuse simplex (EBS) (N=4). Les kĂ©ratinocytes Ă©pidermiques humains normaux (NHEK) ont Ă©tĂ© utilisĂ©s comme contrĂŽles. L'expression des principaux capteurs de l'inflammasome (NOD-like Receptors (NLRs)), des membres de la famille des caspases et des cytokines a Ă©tĂ© dĂ©terminĂ©e. En parallĂšle, la sĂ©crĂ©tion de cytokines a Ă©tĂ© mesurĂ©e par ELISA.Nous avons observĂ© des niveaux Ă©levĂ©s dâexpression de NLRP1, NLRP3, NLRP6, MEFV, NOD2, NLRC4, NLRP4, NLRP10 et NLRP12 dans les kĂ©ratinocytes dĂ©rivĂ©s de patients JEB par rapport aux NHEK. L'expression de NLRP6, MEFV, AIM2 et NLRC4 Ă©tait plus Ă©levĂ©e chez les patients EBS que chez les NHEK. L'expression de CASP1 et CASP4 Ă©tait plus Ă©levĂ©e chez les patients JEB et EBS que chez les NHEK, mais Ă©tait de niveau comparable chez les patients JEB et EBS. L'expression des gĂšnes IL-1B et IL-18 Ă©tait significativement plus Ă©levĂ©e chez les patients JEB que chez les NHEK. La sĂ©crĂ©tion d'IL-1ÎČ Ă©tait significativement plus Ă©levĂ©e chez les patients JEB que chez les EBS ou les contrĂŽles. De façon inattendue, la sĂ©crĂ©tion d'IL-18 Ă©tait infĂ©rieure Ă la limite de dĂ©tection dans tous les groupes.Nos rĂ©sultats ont dĂ©montrĂ© que les kĂ©ratinocytes dĂ©rivĂ©s des patients JEB et EBS prĂ©sentent une expression accrue des composants de l'inflammasome par rapport aux NHEK, ce qui suggĂšre un rĂŽle de l'inflammasome dans l'EB. Le dĂ©rĂšglement des senseurs de l'inflammasome, qui entraĂźne une production excessive de cytokines pro-inflammatoires, pourrait donc contribuer Ă l'inflammation chronique observĂ©e dans l'EB. Des Ă©tudes complĂ©mentaires sur le type d'inflammasome(s) impliquĂ©(s) dans l'EB et lâutilisation ciblĂ©e de modulateurs de lâactivation des inflammasomes pourraient ĂȘtre prometteuses pour le dĂ©veloppement de traitements anti-inflammatoires pour l'EB
Role of lipid phosphate phosphatase 3 in human aortic endothelial cell function
International audienceAims: Lipid phosphate phosphatase 3 (LPP3; PPAP2B) is a transmembrane protein dephosphorylating and thereby terminating signalling of lipid substrates including lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P). Human LPP3 possesses a cell adhesion motif that allows interaction with integrins. A polymorphism (rs17114036) in PPAP2B is associated with coronary artery disease, which prompted us to investigate the possible role of LPP3 in human endothelial dysfunction, a condition promoting atherosclerosis. Methods and results: To study the role of LPP3 in endothelial cells we used human primary aortic endothelial cells (HAECs) in which LPP3 was silenced or overexpressed using either wild type or mutated cDNA constructs. LPP3 silencing in HAECs enhanced secretion of inflammatory cytokines, leukocyte adhesion, cell survival and migration and impaired angiogenesis, whereas wild-type LPP3 overexpression reversed these effects and induced apoptosis. We also demonstrated that LPP3 expression was negatively correlated with VEGF expression. Mutations in either the catalytic or the RGD domains impaired endothelial cell function and pharmacological inhibition of S1P or LPA restored it. LPA was not secreted in HAECs under silencing or overexpressing 2 LPP3. However the intra-and extracellular levels of S1P tended to be correlated with LPP3 expression, indicating that S1P is probably degraded by LPP3. Conclusions: We demonstrated that LPP3 is a negative regulator of inflammatory cytokines, leukocyte adhesion, cell survival and migration in HAECs, suggesting a protective role of LPP3 against endothelial dysfunction in humans. Both the catalytic and the RGD functional domains were involved and S1P, but not LPA, might be the endogenous substrate of LPP3
Role of lipid phosphate phosphatase 3 in human aortic endothelial cell function.
AIMS: Lipid phosphate phosphatase 3; type 2 phosphatidic acid phosphatase ÎČ (LPP3; PPAP2B) is a transmembrane protein dephosphorylating and thereby terminating signalling of lipid substrates including lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P). Human LPP3 possesses a cell adhesion motif that allows interaction with integrins. A polymorphism (rs17114036) in PPAP2B is associated with coronary artery disease, which prompted us to investigate the possible role of LPP3 in human endothelial dysfunction, a condition promoting atherosclerosis. METHODS AND RESULTS: To study the role of LPP3 in endothelial cells we used human primary aortic endothelial cells (HAECs) in which LPP3 was silenced or overexpressed using either wild type or mutated cDNA constructs. LPP3 silencing in HAECs enhanced secretion of inflammatory cytokines, leucocyte adhesion, cell survival, and migration and impaired angiogenesis, whereas wild-type LPP3 overexpression reversed these effects and induced apoptosis. We also demonstrated that LPP3 expression was negatively correlated with vascular endothelial growth factor expression. Mutations in either the catalytic or the arginine-glycine-aspartate (RGD) domains impaired endothelial cell function and pharmacological inhibition of S1P or LPA restored it. LPA was not secreted in HAECs under silencing or overexpressing LPP3. However, the intra- and extra-cellular levels of S1P tended to be correlated with LPP3 expression, indicating that S1P is probably degraded by LPP3. CONCLUSIONS: We demonstrated that LPP3 is a negative regulator of inflammatory cytokines, leucocyte adhesion, cell survival, and migration in HAECs, suggesting a protective role of LPP3 against endothelial dysfunction in humans. Both the catalytic and the RGD functional domains were involved and S1P, but not LPA, might be the endogenous substrate of LPP3
Autoinflammatory Diseases: Germline vs. Somatic Mosaic Variations
National audienceDuring the period of 2018-2023, we have identified 10 pathogenic variations in the NLRP3 gene (Figure 1) including:-8 different mosaic variations in 11 independent patients-2 different germline variations in 3 independent patients. A total of 34 mosaic and 88 germline NLRP3 variations have been reported in the literature to date (Figure 1). Clinically, NLRP3 mosaic variations are associated with various NLRP3-AID phenotypes ranging from late-onset urticaria in the context of MWS to CINCA. Conclusions This study emphasizes the high frequency of somatic mosaic variations in NLRP3-AIDs. The phenotypic spectrum of NLRP3-AIDs appears to be related to both the germinal/mosaic status and the localization in cryopyrin of the underlying variations. Mosaic variations in the NLRP3, TNFRSF1A, and NLRC4 genes can cause symptoms even when present at very low allele frequencies (below 5%). Furthermore, misdiagnosis may occur due to the low allele frequency of mosaic variations
Expression tardive dâune maladie autoinflammatoire : identification et caractĂ©risation fonctionnelle dâune variation de NLRC4 en mosaĂŻque
National audienceIncreased plasma levels of the pro-inflammatory cytokines IL1ÎČ, TNFα, IL6 and IL18 during flares, with sustained elevated levels of IL18 during patient's remission The p.Thr133Ile NLRC4 variation induced increased inflammasome activation The p.Thr133Ile NLRC4 variant activated the NFÎșB pathway Clinical Features The patient is a 28-year-old man with a chronic psychosis since the age of 18 who has been experiencing: Conclusion In this study, we identified a novel mosaic variation of NLRC4 in an adult patient with an autoinflammatory disease. Functional studies demonstrated the gain-of-function pathogenic effect of the identified variation on inflammation. NLRC4 acts as an adaptor protein that is recruited by NAIP to initiate the formation of the NLRC4-NAIP inflammasome upon recognition of bacterial elements. The NLRC4-NAIP inflammasome requires the adaptor protein ASC (apoptotic speck protein containing a CARD) to recruit the caspase-1 protease, which cleaves the pro-interleukins (pro-IL1b and pro-IL18), resulting in the production of their active forms (IL1b and IL18) and triggering the inflammatory response.Introduction. Les maladies autoinflammatoires (MAI) dĂ©butent en rĂšgle dans l'enfance par des crises fĂ©briles spontanĂ©ment rĂ©solutives, accompagnĂ©es d'une inflammation de la peau, des sĂ©reuses et des synoviales. Les mĂ©canismes physiopathologiques touchent les facteurs de l'immunitĂ© innĂ©e, tels que les inflammasomes qui sont des complexes multiprotĂ©iques impliquĂ©s dans l'activation des voies de lâinflammation. NLRC4, qui code pour un composant essentiel de lâinflammasome NLRC4, a Ă©tĂ© impliquĂ© dans des formes trĂšs rares et sĂ©vĂšres de MAI survenant majoritairement chez lâenfant et caractĂ©risĂ©es le plus souvent par une entĂ©rocolite et pouvant se compliquer dâun syndrome dâactivation macrophagique (SAM). Seules 2 variations en mosaĂŻque ont Ă©tĂ© rapportĂ©es chez des patients adultes. Lâobjectif de cette Ă©tude Ă©tait dâidentifier les bases molĂ©culaires dâune MAI ayant dĂ©butĂ© Ă lâĂąge adulte par des crises inflammatoires sĂ©vĂšres associant une fiĂšvre Ă©levĂ©e et des douleursarticulaires et abdominales sans syndrome dâactivation macrophagique.MĂ©thodes. LâADN gĂ©nomique leucocytaire du patient a Ă©tĂ© analysĂ© par le sĂ©quençage (NGS) profond (1100 X) dâun panel de gĂšnes de MAI. LâĂ©valuation fonctionnelle de la variation identifiĂ©e dans NLRC4 a Ă©tĂ© rĂ©alisĂ©e aprĂšs expression de la protĂ©ine recombinante correspondante dans une lignĂ©e HEK293T exprimant diffĂ©rent partenaires protĂ©iques (ASC et Caspase1) permettant la dĂ©tection dâagrĂ©gats (« specks ») tĂ©moins de lâactivation de lâinflammasome NLRC4, et transfectĂ©e par un gĂšne rapporteur de la voie NF-kB. Les taux plasmatiques de cytokines pro-inflammatoires ont Ă©tĂ© dĂ©terminĂ©s par ELISA.RĂ©sultats. Le patient, un jeune homme de 23 ans, prĂ©sentait une psychose non Ă©tiquetĂ©e depuis lâĂąge de 19 ans. Depuis ses 21 ans, des crises inflammatoires sĂ©vĂšres sont rapportĂ©es sans quâun lien direct entre la maladie psychiatrique et les crises inflammatoires nâait pu ĂȘtre Ă©tabli. LâĂ©tude NGS par sĂ©quençage profond a montrĂ© lâexistence dâune variation en mosaĂŻque de NLRC4, c.398C>T p.(Thr133Ile), lâallĂšle mutĂ© Ă©tant reprĂ©sentĂ© Ă 5% au sein de lâADN leucocytaire. LâĂ©tude de lâimpact de la variation p.(Thr133Ile) sur la voie NF-kB a rĂ©vĂ©lĂ© une augmentation significative de l'activitĂ© NF-kB dans les cellules exprimant la forme mutĂ©e de la protĂ©ine par rapport Ă celles exprimant la forme sauvage. ComparĂ©e Ă lâimpact de la version normale de NLRC4 sur la formation de specks, la variationp.(Thre133Ile) induit une augmentation du nombre de specks. Par ailleurs, la quantification des cytokines pro-inflammatoires a montrĂ© des taux plasmatiques Ă©levĂ©s de IL18 compatibles avec une activation de lâinflammasome NLRC4.Conclusion. Cette Ă©tude a permis dâidentifier une nouvelle variation de NLRC4 en mosaĂŻquesâexprimant Ă lâĂąge adulte, sans syndrome dâactivation macrophagique, et dont lâeffet pathogĂšne gain de fonction a Ă©tĂ© dĂ©montrĂ© par des Ă©tudes fonctionnelles sur deux voies de lâinflammation
Identification et caractérisation fonctionnelle de mutations de lyn dans une urticaire auto-inflammatoire syndromique
International audienceLes Maladies auto-inflammatoires (MAI) sont liĂ©es Ă des anomalies gĂ©nĂ©tiques de facteurs impliquĂ©s dans le systĂšme immunitaire et caractĂ©risĂ©es par des accĂšs inflammatoires fĂ©briles rĂ©currents spontanĂ©ment rĂ©solutifs. LYN code pour une protĂ©ine tyrosine kinase, dont lâactivation est rĂ©gulĂ©e par lâĂ©tat de phosphorylation de 2 de ses tyrosines (Y397 et Y508). Dans un modĂšle murin, le knock-in Y508F conduit Ă une hyperactivation de Lyn et au dĂ©veloppement dâune glomĂ©rulonĂ©phrite autoimmune sĂ©vĂšre. A ce jour, 2 patients avec une MAI sĂ©vĂšre de dĂ©but nĂ©onatal et prĂ©sentant chacun une variation de novo du dernier exon de LYN (Y508* et Y508F), non explorĂ©es sur le plan fonctionnel, ont Ă©tĂ© rapportĂ©s lors de confĂ©rences spĂ©cialisĂ©es. MethodesEtude NGS dâun panel de gĂšnes de MAI chez une patiente prĂ©sentant une forme nĂ©onatale sĂ©vĂšre de MAI. Etudes fonctionnelles in vitro des variations LYN : Ă©tude de la phosphorylation de Lyn par western blot et activation de la voie NF-kB par essai lucifĂ©rase dans la lignĂ©e HEK293T. ConclusionIl sâagit de la 1Ăšre dĂ©monstration de la pathogĂ©nicitĂ© des 3 variations de LYN rapportĂ©es chez lâhomme Ă ce jour, et ce par effet gain-de-fonction.Les 3 variations (Y508H, Y508F et Y508*) affectent le mĂȘme rĂ©sidu Tyrosine de la protĂ©ine, soulignant le rĂŽle critique de cet acide aminĂ© dans la rĂ©gulation de lâactivitĂ© de Lyn.Lâanalyse fine du phĂ©notype de ce patient et sa comparaison avec le phĂ©notype des 2 prĂ©cĂ©dents patients rapportĂ©s permet de dĂ©finir un spectre phĂ©notypique de cette MAI associĂ©e Ă des variations gain-de-fonction de LYN
Identification et caractérisation fonctionnelle de mutations de lyn dans une urticaire auto-inflammatoire syndromique
International audienceLes Maladies auto-inflammatoires (MAI) sont liĂ©es Ă des anomalies gĂ©nĂ©tiques de facteurs impliquĂ©s dans le systĂšme immunitaire et caractĂ©risĂ©es par des accĂšs inflammatoires fĂ©briles rĂ©currents spontanĂ©ment rĂ©solutifs. LYN code pour une protĂ©ine tyrosine kinase, dont lâactivation est rĂ©gulĂ©e par lâĂ©tat de phosphorylation de 2 de ses tyrosines (Y397 et Y508). Dans un modĂšle murin, le knock-in Y508F conduit Ă une hyperactivation de Lyn et au dĂ©veloppement dâune glomĂ©rulonĂ©phrite autoimmune sĂ©vĂšre. A ce jour, 2 patients avec une MAI sĂ©vĂšre de dĂ©but nĂ©onatal et prĂ©sentant chacun une variation de novo du dernier exon de LYN (Y508* et Y508F), non explorĂ©es sur le plan fonctionnel, ont Ă©tĂ© rapportĂ©s lors de confĂ©rences spĂ©cialisĂ©es. MethodesEtude NGS dâun panel de gĂšnes de MAI chez une patiente prĂ©sentant une forme nĂ©onatale sĂ©vĂšre de MAI. Etudes fonctionnelles in vitro des variations LYN : Ă©tude de la phosphorylation de Lyn par western blot et activation de la voie NF-kB par essai lucifĂ©rase dans la lignĂ©e HEK293T. ConclusionIl sâagit de la 1Ăšre dĂ©monstration de la pathogĂ©nicitĂ© des 3 variations de LYN rapportĂ©es chez lâhomme Ă ce jour, et ce par effet gain-de-fonction.Les 3 variations (Y508H, Y508F et Y508*) affectent le mĂȘme rĂ©sidu Tyrosine de la protĂ©ine, soulignant le rĂŽle critique de cet acide aminĂ© dans la rĂ©gulation de lâactivitĂ© de Lyn.Lâanalyse fine du phĂ©notype de ce patient et sa comparaison avec le phĂ©notype des 2 prĂ©cĂ©dents patients rapportĂ©s permet de dĂ©finir un spectre phĂ©notypique de cette MAI associĂ©e Ă des variations gain-de-fonction de LYN
Proteasomal degradation of NOD2 by NLRP12 in monocytes promotes bacterial tolerance and colonization by enteropathogens
Mutations in nucleotide-binding oligomerization domain protein 12 (NLRP12) are known to effect inflammatory processes. Here the authors show that NLRP12-mediated proteasomal degradation of NOD2 in monocytes promotes bacterial tolerance and colonisation in a model of enteric infection