Assessment of podocyte injury using two novel glomerular markers

The glomerular filtration barrier is an efficient filtration system, which ensures proper function of the kidney by avoiding proteinuria. At the same time, this barrier is also the most vulnerable component of the kidney. The podocyte, a terminal differentiated cell, is the key player in maintaining integrity. Most of the kidney diseases initiate from injuries of the podocytes, which lead to effacement with slit diaphragm disruption, followed ultimately by cell detachment and loss. Such a lesion can only be detected by electron microscopy. The goal of the present work was to identify early marker(s) of podocyte injury, which are uniquely expressed in these cells and are very sensitive to stress or any other type of insults. With such marker at hand, early evaluation of podocyte injury and disease progression to the entire nephron can be explored. By applying gene expression profile analysis on laser capture microdissected glomeruli two novel podocytes markers, Semaphorin-3G (Sema3G) and Cystatin C (CYTC) could be identified. Their specific expression in podocytes was further confirmed by the use of in situ hybridization and immunohistochemistry on kidney tissue sections. In a next step, modulation of Sema3G and CYTC was further assessed in models of podocyte injury (functional injury, immune-deposition related injury and drug-induced toxicity models). Sema3G is a very sensitive marker to podocyte injury, which was down regulated in all animal model tested except functional injury model. In the opposite, CYTC was upregulated only in the drug-induced toxicity model. By combining the in situ localization of these newly characterized markers with the well validated kidney injury molecule -1 (KIM-1), it was possible to follow the sequence of events from early podocyte injury to entire nephron damage. Hence, this represents a valuable tool for exploring the pathogenesis of glomerulopathy

Xenobiotic CAR activators induce Dlk1-Dio3 locus non-coding RNA expression in mouse liver

Predicting the impact of human exposure to chemicals such as pharmaceuticals and agrochemicals requires the development of reliable and predictive biomarkers suitable for the detection of early events potentially leading to adverse outcomes. In particular, drug-induced non-genotoxic carcinogenesis (NGC) during preclinical development of novel therapeutics intended for chronic administration in humans is a major challenge for drug safety. We previously demonstrated Constitutive Androstane Receptor (CAR) and WNT signaling-dependent up-regulation of the pluripotency associated Dlk1-Dio3 imprinted gene cluster non-coding RNAs (ncRNAs) in the liver of mice treated with tumorpromoting doses of phenobarbital (PB). Here, to explore the sensitivity and the specificity of this candidate liver tumor promotion ncRNAs signature we compared phenotypic, transcriptional and proteomic data from wild-type, CAR/PXR double knock-out and CAR/PXR double humanized animals treated with tumor-promoting doses of PB or chlordane, both well-established CAR activators. We further investigated selected transcriptional profiles from mouse liver samples exposed to seven NGC compounds working through different mode of actions, overall suggesting CAR-activation specificity of the Dlk1-Dio3 long ncRNAs activation. We propose that Dlk1-Dio3 long ncRNAs up-regulation is an early CAR-activation dependent transcriptional signature during xenobiotic-induced mouse liver tumor promotion. This signature may further contribute mode of action-based ‘weight of evidence’ cancer risk assessment for xenobiotic-induced rodent liver tumors

Drug-induced chromatin accessibility changes associate with sensitivity to liver tumor promotion

Liver cancer susceptibility varies amongst humans and between experimental animal models due to multiple genetic and epigenetic factors. The molecular characterization of such susceptibilities has the potential to enhance cancer risk assessment of xenobiotic exposures and disease prevention strategies. Here, using DNase I hypersensitivity mapping coupled with transcriptomic profiling, we investigate perturbations in cis-acting gene regulatory elements associated with the early stages of phenobarbital (PB)- mediated liver tumor promotion in susceptible versus resistant mouse strains (B6C3F1 versus C57BL/6J). Integrated computational analyses of strain-selective changes in liver chromatin accessibility underlying PB-response reveal differential epigenetic regulation of molecular pathways associated with PB-mediated tumor promotion, including Wnt/-catenin signalling. Complementary transcription factor motif analyses reveal mouse strain-selective gene regulatory networks and a novel role for Stat, Smad and Fox transcription factors in the early stages of PB-mediated tumor promotion. Mapping perturbations in cis-acting gene regulatory elements provides novel insights into the molecular basis for susceptibility to xenobiotic-induced rodent liver tumor promotion and has the potential to enhance mechanism-based cancer risk assessments of xenobiotic exposures

Symptom-based stratification of patients with primary Sjögren's syndrome: multi-dimensional characterisation of international observational cohorts and reanalyses of randomised clinical trials

Background Heterogeneity is a major obstacle to developing effective treatments for patients with primary Sjögren's syndrome. We aimed to develop a robust method for stratification, exploiting heterogeneity in patient-reported symptoms, and to relate these differences to pathobiology and therapeutic response. Methods We did hierarchical cluster analysis using five common symptoms associated with primary Sjögren's syndrome (pain, fatigue, dryness, anxiety, and depression), followed by multinomial logistic regression to identify subgroups in the UK Primary Sjögren's Syndrome Registry (UKPSSR). We assessed clinical and biological differences between these subgroups, including transcriptional differences in peripheral blood. Patients from two independent validation cohorts in Norway and France were used to confirm patient stratification. Data from two phase 3 clinical trials were similarly stratified to assess the differences between subgroups in treatment response to hydroxychloroquine and rituximab. Findings In the UKPSSR cohort (n=608), we identified four subgroups: Low symptom burden (LSB), high symptom burden (HSB), dryness dominant with fatigue (DDF), and pain dominant with fatigue (PDF). Significant differences in peripheral blood lymphocyte counts, anti-SSA and anti-SSB antibody positivity, as well as serum IgG, κ-free light chain, β2-microglobulin, and CXCL13 concentrations were observed between these subgroups, along with differentially expressed transcriptomic modules in peripheral blood. Similar findings were observed in the independent validation cohorts (n=396). Reanalysis of trial data stratifying patients into these subgroups suggested a treatment effect with hydroxychloroquine in the HSB subgroup and with rituximab in the DDF subgroup compared with placebo. Interpretation Stratification on the basis of patient-reported symptoms of patients with primary Sjögren's syndrome revealed distinct pathobiological endotypes with distinct responses to immunomodulatory treatments. Our data have important implications for clinical management, trial design, and therapeutic development. Similar stratification approaches might be useful for patients with other chronic immune-mediated diseases. Funding UK Medical Research Council, British Sjogren's Syndrome Association, French Ministry of Health, Arthritis Research UK, Foundation for Research in Rheumatology

Intérêt de l'électrophorèse capillaire comme technique alternative dans la séparation d'un principe actif et de ses deux isomères

BORDEAUX2-BU Santé (330632101) / SudocSudocFranceF

Radiotracers for the Central Serotoninergic System

International audienceThis review lists the most important radiotracers described so far for imaging the central serotoninergic system. Single-photon emission computed tomography and positron emission tomography radiotracers are reviewed and critically discussed for each receptor

A general synthesis of diversely substituted indazoles and hetero-aromatic derivatives from o-halo-(het)arylaldehydes or -phenones

International audienceA set of variously substituted indazoles and hetero-aromatic derivatives were synthesized from o-halo-(het)arylaldehydes using a palladium catalyzed amination followed by cyclization. Starting from phenones, this process was extended to give 3-substituted indazoles. Moreover, N-1-substituted-indazoles can be reached by this strategy using an optional selective N-1-alkylation step during the process. This methodology offers a general and easy route for the synthesis of regioselectively substituted indazoles

Fingolimod inhibits brain atrophy and promotes brain-derived neurotrophic factor in an animal model of multiple sclerosis

Longitudinal brain atrophy quantification is a critical efficacy measurement in multiple sclerosis (MS) clinical trials and the determination of No Evidence of Disease Activity (NEDA). Utilising fingolimod as a clinically validated therapy we evaluated the use of repeated brain tissue volume measures during chronic experimental autoimmune encephalomyelitis (EAE) as a new preclinical efficacy measure. Brain volume changes were quantified using magnetic resonance imaging (MRI) at 7 Tesla and correlated to treatment-induced brain derived neurotrophic factor (BDNF) measured in blood, cerebrospinal fluid, spinal cord and brain. Serial brain MRI measurements revealed slow progressive brain volume loss in vehicle treated EAE mice despite a stable clinical score. Fingolimod (1 mg/kg) significantly ameliorated brain tissue atrophy in the cerebellum and striatum when administered from established EAE disease onwards. Fingolimod-dependent tissue preservation was associated with induction of BDNF specifically within the brain and co-localized with neuronal soma. In contrast, therapeutic teriflunomide (3 mg/kg) treatment failed to inhibit CNS autoimmune mediated brain degeneration. Finally, weekly anti-IL-17A antibody (15 mg/kg) treatment was highly efficacious and preserved whole brain, cerebellum and striatum volume. Fingolimod-mediated BDNF increases within the CNS may contribute to limiting progressive tissue loss during chronic neuroinflammation

Epidemiology of neurological manifestations in Sjögren's syndrome: data from the French ASSESS Cohort

International audienc