Integrin Alpha 8 Recessive Mutations Are Responsible for Bilateral Renal Agenesis in Humans

Renal hypodysplasia (RHD) is a heterogeneous condition encompassing a spectrum of kidney development defects including renal agenesis, hypoplasia, and (cystic) dysplasia. Heterozygous mutations of several genes have been identified as genetic causes of RHD with various severity. However, these genes and mutations are not associated with bilateral renal agenesis, except for RET mutations, which could be involved in a few cases. The pathophysiological mechanisms leading to total absence of kidney development thus remain largely elusive. By using a whole-exome sequencing approach in families with several fetuses with bilateral renal agenesis, we identified recessive mutations in the integrin α8-encoding gene ITGA8 in two families. Itga8 homozygous knockout in mice is known to result in absence of kidney development. We provide evidence of a damaging effect of the human ITGA8 mutations. These results demonstrate that mutations of ITGA8 are a genetic cause of bilateral renal agenesis and that, at least in some cases, bilateral renal agenesis is an autosomal-recessive disease

Vers la caractérisation de deux mécanismes pour le néphroblastome

Le néphroblastome, ou tumeur de Wilms, est une tumeur d'origine embryonnaire dans laquelle coexistent, en proportions variables, les différents types cellulaires du rein en différenciation : blastème, tubes et glomérules, ainsi que du stroma. Mon travail de thèse a consisté à préciser la caractérisation des néphroblastomes et d'améliorer la compréhension des mécanismes associés. J'ai tout d'abord réalisé l'analyse d'une série de 60 tumeurs, en combinant la recherche de mutations et l'analyse de l'expression des gènes WT1 et CTNNB1 avec l'analyse pangénomique des profils transcriptionnels et génomiques. J'ai ainsi confirmé l'existence de deux classes bien distinctes de néphroblastome présentant des profils transcriptionnels et génomiques spécifiques. Puis j'ai élaboré un modèle cellulaire de néphroblastome. Enfin, nous avons identifié des mutations de WTX dans 16 % de ces tumeurs et nous avons confirmé qu'elles sont indépendantes des mutations de WT1/CTNNB1 et associées au mauvais pronostic.Based on a tumor classification that took into account both genomic and expression status of WTl,beta-catenin and WTX, combined with genome-wide expression and genomic profiling analyses, we present the first molecular evidence that dysregulation of the Wnt pathway occurs in all tumors, with and without CTNNB1 mutations. Our strategy of sample class comparison including comparisons with control samples allowed us to identified two sets of target genes, one specific of tumors with WTl/beta-catenin alterations and one common to all tumors. We present evidence that activation of the Wnt pathway in absence ofCTNNBl mutations is not restricted to rumors with WTX mutations. By genome transcriptome correlation analysis, we identified genes encoding Wnt pathway regulators (BCL9, CTNNBIP1 and CBY1) whose dysregulation in tumors with chromosomal gain or losses could participate in Wnt pathway activation. Finally, we present data suggesting the prognostic value of WTX mutations.PARIS5-BU Méd.Cochin (751142101) / SudocSudocFranceF

L9, a novel and promising monoclonal antibody against Malaria

International audienceDans le cadre de leur module d’analyse scientifique, des étudiants de la promotion 2020-2021 des Master 2 « Immunologie Translationnelle et Biothérapies » (ITB) et « Immunologie Intégrative et Systémique » (I2S) (Mention Biologie Moléculaire et Cellulaire, Parcours Immunologie, Sorbonne Université) se sont penchés sur la littérature et ont pris la plume pour partager avec les lecteurs de m/s quelques-uns des faits marquants de l’actualité en immunologie. Voici une sélection de quelques-unes de ces nouvelles, illustrant la large palette des axes de recherche en cours sur les mécanismes physiopathologiques des maladies infectieuses, auto-immunes, inflammatoires et tumorales et sur le développement d’immunothérapies pour le traitement de ces maladies

Efficacy and safety of nivolumab in patients with non-small cell lung cancer: a retrospective study in clinical practice.

MEDLINE:30595104Nivolumab, a fully human immunoglobulin monoclonal antibody inhibiting the programmed cell death protein-1 receptor, demonstrated robust efficacy and a manageable safety profile across multiple tumor types in clinical trials. The aim of the present study was to investigate the efficacy and safety of nivolumab for pretreated patients with non-small cell lung cancers in clinical practice. In this observational monocentric retrospective study, 98 patients were enrolled between February 2015 and February 2016. The global median overall survival was 6.34 months (95% confidence interval (CI) : 4.11-10.88) and the global median progression free survival was 1.84 months (95% CI: 1.68-2.73). In the univariate analysis, clinical performance status score was the only factor significantly correlated with overall survival. The safety profile of nivolumab is consistent with that described in prior studies, with only 7% undesirable effects requiring the discontinuation of treatment. The results of the present study demonstrate that nivolumab affords clinical efficacy and manageable tolerability in patients with non-small cell lung cancers

A minimal standardized human bone marrow microphysiological system to assess resident cell behavior during normal and pathological processes

International audienceBone marrow is a complex and dynamic microenvironment that provides essential cues to resident cells.We developed a standardized three-dimensional (3D) model to decipher mechanisms that control humancells during hematological and non-hematological processes. Our simple 3D-model is constituted of abiphasic calcium phosphate-based scaffold and human cell lines to ensure a high reproducibility. Weobtained a minimal well-organized bone marrow-like structure in which various cell types and secretedextracellular matrix can be observed and characterized by in situ imaging or following viable cell retrieval.The complexity of the system can be increased and customized, with each cellular component beingindependently modulated according to the issue investigated. Introduction of pathological elements inthis 3D-system accurately reproduced changes observed in patient bone marrow. Hence, we have developeda handy and flexible standardized microphysiological system that mimics human bone marrow,allowing histological analysis and functional assays on collected cells

« La modernité dure longtemps »

Dans son livre Discordance des temps. Une brève histoire de la modernité, paru en 2011, Christophe Charle reprend les différents objets et questionnements qui traversent toute son œuvre pour élaborer une histoire sociale et culturelle de l’idée de modernité. Dans le sillage de cet essai, le présent recueil explore la question des temporalités en étudiant les tensions, les décalages et les distorsions qui n’ont cessé de modeler, depuis deux siècles, les visions du passé et de l’avenir. Adoptant des démarches et approchant des terrains variés, les auteurs ici réunis ont pour point commun de fonder leurs interrogations sur celles formulées par Christophe Charle, dans un dialogue nourri. Qu’il prenne la forme d’essais de synthèse sur l’État moderne, l’expérience de l’exil ou la Commune, d’études de cas autour d’événements qui font rupture (1871, 1945, 1968), ou de portraits d’intellectuels, tels ceux de l’abbé Grégoire ou Jacques Ellul, ce projet articule le concept de modernité à chacune des sociétés ici étudiées qui l’a expérimentée. Cette approche anime les recherches et guide les travaux de la plupart des ancien·ne·s étudiant·es ou des proches de Christophe Charle qui ont accepté de contribuer à ce livre d’hommages, dont l’ambition est bien de passer d’une histoire hors-sol de la modernité à une histoire sociale et culturelle des expériences du temps et de l’avenir. Déjouant la difficulté d’accès aux sources comme à la parole des acteurs, écrire une histoire des pratiques de construction du temps social a aussi consisté à approfondir un travail collectif engagé depuis plusieurs décennies en l’inscrivant au présent des crises à répétition de la modernité

Mutations in GREB1L Cause Bilateral Kidney Agenesis in Humans and Mice

International audienceCongenital anomalies of the kidney and urinary tract (CAKUT) constitute a major cause of chronic kidney disease in children and 20% of prenatally detected anomalies. CAKUT encompass a spectrum of developmental kidney defects, including renal agenesis, hypoplasia, and cystic and non-cystic dysplasia. More than 50 genes have been reported as mutated in CAKUT-affected case subjects. However, the pathophysiological mechanisms leading to bilateral kidney agenesis (BKA) remain largely elusive. Whole-exome or targeted exome sequencing of 183 unrelated familial and/or severe CAKUT-affected case subjects, including 54 fetuses with BKA, led to the identification of 16 heterozygous variants in GREB1L (growth regulation by estrogen in breast cancer 1-like), a gene reported as a target of retinoic acid signaling. Four loss-of-function and 12 damaging missense variants, 14 being absent from GnomAD, were identified. Twelve of them were present in familial or simplex BKA-affected case subjects. Female BKA-affected fetuses also displayed uterus agenesis. We demonstrated a significant association between GREB1L variants and BKA. By in situ hybridization, we showed expression of Greb1l in the nephrogenic zone in developing mouse kidney. We generated a Greb1l knock-out mouse model by CRISPR-Cas9. Analysis at E13.5 revealed lack of kidneys and genital tract anomalies in male and female Greb1l-/- embryos and a slight decrease in ureteric bud branching in Greb1l+/- embryos. We showed that Greb1l invalidation in mIMCD3 cells affected tubulomorphogenesis in 3D-collagen culture, a phenotype rescued by expression of the wild-type human protein. This demonstrates that GREB1L plays a major role in early metanephros and genital development in mice and humans

RET and GDNF mutations are rare in fetuses with renal agenesis or other severe kidney development defects

International audienceBackground The RET/GDNF signalling pathway plays a crucial role during development of kidneys and enteric nervous system. In humans, RET activating mutations cause multiple endocrine neoplasia, whereas inactivating mutations are responsible for Hirschsprung disease. RET mutations have also been reported in fetuses with renal agenesis, based on analysis of a small series of samples. Objective and Methods To better characterize the involvement of RET and GDNF in kidney development defects, we studied a series of 105 fetuses with bilateral defects including renal agenesis, severe hypodysplasia or multicystic dysplastic kidney. RET and GDNF coding sequences, evolutionary conserved non-coding regions (ECRs) in promoters, 3'UTRs and RET intron 1 were analysed. Copy number variations (CNVs) at these loci were also investigated. Results We identified: (i) a low frequency (< 7%) of potential mutations in the RET coding sequence, with inheritance from the healthy father for four of them; (ii) no GDNF mutation; (iii) similar allele frequencies in patients and controls for most SNP variants, except for RET intron 1 variant rs2506012 that was significantly more frequent in affected fetuses than in controls (6% vs. 2%, P=0.01); (iv) distribution of the few rare RET variants unidentified in controls into the various 5'-ECRs; (v) absence of CNVs. Conclusion These results suggest that genomic alteration of RET or GDNF is not a major mechanism leading to renal agenesis and other severe kidney development defects. Analysis of a larger series of patients will be necessary to validate the association of the RET intron 1 variant rs2506012 with renal development defects

A nanobody against the VWF A3 domain detects ADAMTS13-induced proteolysis in congenital and acquired VWD

International audienceAbstract von Willebrand factor (VWF) is a multimeric protein, the size of which is regulated via ADAMTS13-mediated proteolysis within the A2 domain. We aimed to isolate nanobodies distinguishing between proteolyzed and non-proteolyzed VWF, leading to the identification of a nanobody (designated KB-VWF-D3.1) targeting the A3 domain, the epitope of which overlaps the collagen-binding site. Although KB-VWF-D3.1 binds with similar efficiency to dimeric and multimeric derivatives of VWF, binding to VWF was lost upon proteolysis by ADAMTS13, suggesting that proteolysis in the A2 domain modulates exposure of its epitope in the A3 domain. We therefore used KB-VWF-D3.1 to monitor VWF degradation in plasma samples. Spiking experiments showed that a loss of 10% intact VWF could be detected using this nanobody. By comparing plasma from volunteers to that from congenital von Willebrand disease (VWD) patients, intact-VWF levels were significantly reduced for all VWD types, and most severely in VWD type 2A–group 2, in which mutations promote ADAMTS13-mediated proteolysis. Unexpectedly, we also observed increased proteolysis in some patients with VWD type 1 and VWD type 2M. A significant correlation (r = 0.51, P &lt; .0001) between the relative amount of high–molecular weight multimers and levels of intact VWF was observed. Reduced levels of intact VWF were further found in plasmas from patients with severe aortic stenosis and patients receiving mechanical circulatory support. KB-VWF-D3.1 is thus a nanobody that detects changes in the exposure of its epitope within the collagen-binding site of the A3 domain. In view of its unique characteristics, it has the potential to be used as a diagnostic tool to investigate whether a loss of larger multimers is due to ADAMTS13-mediated proteolysis