Expression et purification de l'ADN topoisomérase I humaine

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

Genetic ablation of calcium-independent phospholipase A2γ induces glomerular injury in mice

Glomerular visceral epithelial cells (podocytes) play a critical role in the maintenance of glomerular permselectivity. Podocyte injury, manifesting as proteinuria, is the cause of many glomerular diseases. We reported previously that calcium-independent phospholipase A(2)γ (iPLA(2)γ) is cytoprotective against complement-mediated glomerular epithelial cell injury. Studies in iPLA(2)γ KO mice have demonstrated an important role for iPLA(2)γ in mitochondrial lipid turnover, membrane structure, and metabolism. The aim of the present study was to employ iPLA(2)γ KO mice to better understand the role of iPLA(2)γ in normal glomerular and podocyte function as well as in glomerular injury. We show that deletion of iPLA(2)γ did not cause detectable albuminuria; however, it resulted in mitochondrial structural abnormalities and enhanced autophagy in podocytes as well as loss of podocytes in aging KO mice. Moreover, after induction of anti-glomerular basement membrane nephritis in young mice, iPLA(2)γ KO mice exhibited significantly increased levels of albuminuria, podocyte injury, and loss of podocytes compared with wild type. Thus, iPLA(2)γ has a protective functional role in the normal glomerulus and in glomerulonephritis. Understanding the role of iPLA(2)γ in glomerular pathophysiology provides opportunities for the development of novel therapeutic approaches to glomerular injury and proteinuria

Higher maternal leptin levels at second trimester are associated with subsequent greater gestational weight gain in late pregnancy

Background: Excessive gestational weight gain (GWG) is associated with adverse pregnancy outcomes. In non-pregnant populations, low leptin levels stimulate positive energy balance. In pregnancy, both the placenta and adipose tissue contribute to circulating leptin levels. We tested whether maternal leptin levels are associated with subsequent GWG and whether this association varies depending on stage of pregnancy and on maternal body mass index (BMI). Methods: This prospective cohort study included 675 pregnant women followed from 1st trimester until delivery. We collected anthropometric measurements, blood samples at 1st and 2nd trimester, and clinical data until delivery. Maternal leptin was measured by ELISA (Luminex technology). We classified women by BMI measured at 1st trimester: BMI < 25 kg/m2 = normal weight; 25 ≤ BMI < 30 kg/m2 = overweight; and BMI ≥ 30 kg/m2 = obese. Results: Women gained a mean of 6.7 ± 3.0 kg between 1st and 2nd trimester (mid pregnancy GWG) and 5.6 ± 2.5 kg between 2nd and the end of 3rd trimester (late pregnancy GWG). Higher 1st trimester leptin levels were associated with lower mid pregnancy GWG, but the association was no longer significant after adjusting for % body fat (%BF; β = 0.38 kg per log-leptin; SE = 0.52; P = 0.46). Higher 2nd trimester leptin levels were associated with greater late pregnancy GWG and this association remained significant after adjustment for BMI (β = 2.35; SE = 0.41; P < 0.0001) or %BF (β = 2.01; SE = 0.42; P < 0.0001). In BMI stratified analyses, higher 2nd trimester leptin levels were associated with greater late pregnancy GWG in normal weight women (β = 1.33; SE = 0.42; P = 0.002), and this association was stronger in overweight women (β = 2.85; SE = 0.94; P = 0.003 – P for interaction = 0.05). Conclusions: Our results suggest that leptin may regulate weight gain differentially at 1st versus 2nd trimester of pregnancy: at 2nd trimester, higher leptin levels were associated with greater subsequent weight gain – the opposite of its physiologic regulation in non-pregnancy – and this association was stronger in overweight women. We suspect the existence of a feed-forward signal from leptin in second half of pregnancy, stimulating a positive energy balance and leading to greater weight gain. Electronic supplementary material The online version of this article (doi:10.1186/s12884-016-0842-y) contains supplementary material, which is available to authorized users

Hibernating brown bears are protected against atherogenic dyslipidemia

publishedVersio

The logic of transcriptional regulator recruitment architecture at cis-regulatory modules controlling liver functions.

Control of gene transcription relies on concomitant regulation by multiple transcriptional regulators (TRs). However, how recruitment of a myriad of TRs is orchestrated at cis-regulatory modules (CRMs) to account for coregulation of specific biological pathways is only partially understood. Here, we have used mouse liver CRMs involved in regulatory activities of the hepatic TR, NR1H4 (FXR; farnesoid X receptor), as our model system to tackle this question. Using integrative cistromic, epigenomic, transcriptomic, and interactomic analyses, we reveal a logical organization where trans-regulatory modules (TRMs), which consist of subsets of preferentially and coordinately corecruited TRs, assemble into hierarchical combinations at hepatic CRMs. Different combinations of TRMs add to a core TRM, broadly found across the whole landscape of CRMs, to discriminate promoters from enhancers. These combinations also specify distinct sets of CRM differentially organized along the genome and involved in regulation of either housekeeping/cellular maintenance genes or liver-specific functions. In addition to these TRMs which we define as obligatory, we show that facultative TRMs, such as one comprising core circadian TRs, are further recruited to selective subsets of CRMs to modulate their activities. TRMs transcend TR classification into ubiquitous versus liver-identity factors, as well as TR grouping into functional families. Hence, hierarchical superimpositions of obligatory and facultative TRMs bring about independent transcriptional regulatory inputs defining different sets of CRMs with logical connection to regulation of specific gene sets and biological pathways. Altogether, our study reveals novel principles of concerted transcriptional regulation by multiple TRs at CRMs

Macrophage Migration Inhibitory Factor Antagonist Blocks the Development of Endometriosis In Vivo

Endometriosis, a disease of reproductive age women, is a major cause of infertility, menstrual disorders and pelvic pain. Little is known about its etiopathology, but chronic pelvic inflammation is a common feature in affected women. Beside symptomatic treatment of endometriosis-associated pain, only two main suboptimal therapeutic approaches (hormonal and invasive surgery) are generally recommended to patients and no specific targeted treatment is available. Our studies led to the detection of a marked increase in the expression of macrophage migration inhibitory factor (MIF) in the eutopic endometrium, the peripheral blood and the peritoneal fluid of women with endometriosis, and in early, vascularized and active endometriotic lesions. Herein, we developed a treatment model of endometriosis, where human endometrial tissue was first allowed to implant into the peritoneal cavity of nude mice, to assess in vivo the effect of a specific antagonist of MIF (ISO-1) on the progression of endometriosis and evaluate its efficacy as a potential therapeutic tool. Administration of ISO-1 led to a significant decline of the number, size and in situ dissemination of endometriotic lesions. We further showed that ISO-1 may act by significantly inhibiting cell adhesion, tissue remodeling, angiogenesis and inflammation as well as by altering the balance of pro- and anti-apoptotic factors. Actually, mice treatment with ISO-1 significantly reduced the expression of cell adhesion receptors αv and ß3 integrins (P<0.05), matrix metalloproteinases (MMP) 2 and 9 (P<0.05), vascular endothelial cell growth factor (VEGF) (P<0.01), interleukin 8 (IL8) (P<0.05), cyclooxygenease (COX)2 (P<0.001) and the anti-apoptotic protein Bcl2 (P<0.01), but significantly induced the expression of Bax (P<0.05), a potent pro-apoptotic protein. These data provide evidence that specific inhibition of MIF alters endometriotic tissue growth and progression in vivo and may represent a promising potential therapeutic avenue

Création d une fiche de liaison entre l hôpital et les médecins généralistes concernant les soins de support auprès de patients atteints de cancer et évaluation de son impact.

Contexte : Les soins de support sont définies comme l ensemble des soins et des soutiens nécessaires aux personnes malades tout au long de la maladie conjointement aux traitements oncologiques ou oncohématologiques spécifiques, lorsqu il y en a. . Il ne s agit pas d une nouvelle discipline mais d une coordination et d une continuité des soins. Le médecin généraliste connaît-il cette prise en charge hospitalière ? Méthode : Nous avons réalisé une étude prospective quasi expérimentale de type avant-après impliquant les médecins généralistes référents de patients atteints de cancer. L intervention réalisée consistait en l envoi d une fiche de liaison en soin de support. Résultats : 42 patients et 42 médecins traitants ont été inclus. Dans le groupe de médecins généralistes n ayant pas reçu la fiche de liaison, ceux-ci savaient si leur patient avait bénéficié de l intervention d un professionnel de recours lors de leur séjour au CHU de Grenoble dans 19 % des cas pour la psychologue, 14 % pour l assistante sociale, 9,5 % pour la diététicienne et 52 % pour les médecins de soins palliatifs. Dans la seconde partie de l étude, l envoi de la fiche de liaison étaient associée à une augmentation significative de la proportion de médecins sachant si leur patient avaient bénéficié de l intervention de la psychologue (95 % versus 19 %, p<0,001), de l assistante sociale (95 % versus 14 %, p<0,001), de l équipe de nutrition (86 % versus 9,5 %), des médecins de soins palliatifs (90% versus 52 %, p<0,005). Conclusion : Un défaut d information existe entre l hôpital et les médecins généralistes à propos des soins de support. La fiche de liaison crée permet d y remédier.GRENOBLE1-BU Médecine pharm. (385162101) / SudocSudocFranceF

[Effectiveness of a supportive care form for family physicians].

International audienceTo assess the effectiveness of a standardized form in altering family physicians knowledge regarding supportive care delivered to their patients. We conducted an uncontrolled before and after study involving 42 cancer patients who were provided with supportive care at hospital. During the intervention study period, a standardized form was sent to their family physician within 1 week of discharge. The use of the standardized form was associated with an increase in the percentages of correct answers regarding consultations with psychologists (95% versus 19%, P < 0.001), social workers (95% versus 14%, P < 0.001), nutritionists (86% versus 9%, P < 0.001), and palliative care physicians (90% versus 52 %, P = 0.006). Yet, the percentages of correct answers regarding discharge arrangements did not differ between the two study groups. The use of a standardized form improves family physician information regarding supportive care delivered to their patients during hospital course but does not alter information on discharge arrangements and follow-up

Regulation of Ste20-like kinase, SLK, activity: Dimerization and activation segment phosphorylation

The Ste20-like kinase, SLK, has diverse cellular functions. SLK mediates organ development,cell cycle progression, cytoskeletal remodeling, cytokinesis, and cell survival.Expression and activity of SLK are enhanced in renal ischemia-reperfusion injury, and overexpressionof SLK was shown to induce apoptosis in cultured glomerular epithelial cells(GECs) and renal tubular cells, as well as GEC/podocyte injury in vivo. The SLK protein consistsof a N-terminal catalytic domain and an extensive C-terminal domain, which containscoiled-coils. The present study addresses the regulation of SLK activity. Controlled dimerizationof the SLK catalytic domain enhanced autophosphorylation of SLK at T183 andS189, which are located in the activation segment. The full-length ectopically- and endogenously-expressed SLK was also autophosphorylated at T183 and S189. Using ezrin as amodel SLK substrate (to address exogenous kinase activity), we demonstrate that dimerizedSLK 1±373 or full-length SLK can effectively induce activation-specific phosphorylationof ezrin. Mutations in SLK, including T183A, S189A or T193A reduced T183 or S189 autophosphorylation,and showed a greater reduction in ezrin phosphorylation. Mutations in thecoiled-coil region of full-length SLK that impair dimerization, in particular I848G, significantlyreduced ezrin phosphorylation and tended to reduce autophosphorylation of SLK at T183. [...