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Background Deciphering the genetic architecture of cardiac disorders is of fundamental importance but their underlying complexity is a major hurdle. Drosophila has gained importance as a useful model to study heart development and function and allows the analysis of organismal traits in a physiologically relevant and accessible system. Our aim was to (i) identify in flies the loci associated to natural variations of cardiac performances among a natural population, (ii) decipher how these variants interact with each other and with the environment to impact cardiac traits, (iii) gain insights about the molecular and cellular processes affected, (iv) determine whether the genetic architecture of cardiac disorders is conserved with humans. Methods and Results We investigated the genetic architecture of natural variations of cardiac performance in the sequenced inbred lines of the Drosophila Genetic Reference Panel (DGRP). Genome Wide Associations (GWA) for single markers and epistatic interactions identified genetic networks associated with natural variations of cardiac traits that were extensively validated in vivo. Non-coding variants were used to map potential regulatory non-coding regions which in turn were employed to predict Transcription Factors (TFs) binding sites. Cognate TFs, many of which themselves bear polymorphisms associated with variations of cardiac performance, were validated by heart specific knockdown. We also analyzed natural variations of cardiac traits variance that revealed unique features of their micro-environmental plasticity. More importantly, correlations between genes associated with cardiac phenotypes both in flies and in humans support the conserved genetic architecture of cardiac functioning from arthropods to mammals. The characteristics of natural variations in cardiac function established in Drosophila may thus guide the analysis of cardiac disorders in humans. Using human iPSC-derived cardiomyocytes, we indeed characterized a conserved function for PAX9 and EGR2 in the regulation of the cardiac rhythm Conclusion In-depth analysis of the genetic architecture of natural variations of cardiac performance in flies combined with functional validations in vivo and in human iPSC-CM represents a major achievement in understanding the mechanisms underlying the genetic architecture of these complex traits and a valuable resource for the identification of genes and mechanisms involved in cardiac disorders in humans.

Global change scenarios in the Mediterranean basin predict a precipitation reduction within the coming hundred years. Therefore, increased drought will affect forests both in terms of adaptive ecology and ecosystemic services. However, how vegetation might adapt to drought is poorly understood. In this report, four years of climate change was simulated by excluding 35% of precipitation above a downy oak forest. RNASeq data allowed us to assemble a genome-guided transcriptome. This led to the identification of differentially expressed features, which was supported by the characterization of target metabolites using a metabolomics approach. We provided 2.5 Tb of RNASeq data and the assembly of the first genome guided transcriptome of Quercus pubescens. Up to 5724 differentially expressed transcripts were obtained, 42 involved in plant response to drought. Transcript set enrichment analysis showed that drought induces an increase in oxidative pressure that is mitigated by the upregulation of ubiquitin-like protein protease, ferrochelatase, oxaloacetate decarboxylase and oxo-acid-lyase activities. Furthermore, the downregulation of auxin biosynthesis and transport, carbohydrate storage metabolism were observed as well as the concomitant accumulation of metabolites, such as oxalic acid, malate and isocitrate. Our data suggest that early metabolic changes in the resistance of Q. pubescens to drought involve a tricarboxylic acid (TCA) cycle shunt through the glyoxylate pathway, galactose metabolism by reducing carbohydrate storage and increased proteolytic activity.

International audience; The Ikzf1 locus encodes the lymphoid specific transcription factor Ikaros, which plays an essential role in both T and B cell differentiation, while deregulation or mutation of IKZF1/ Ikzf1 is involved in leukemia. Tissue-specific and cell identity genes are usually associated with clusters of enhancers, also called super-enhancers, which are believed to ensure proper regulation of gene expression throughout cell development and differentiation. Several potential regulatory regions have been identified in close proximity of Ikzf1, however, the full extent of the regulatory landscape of the Ikzf1 locus is not yet established. In this study, we combined epigenomics and transcription factor binding along with high-through-put enhancer assay and 4C-seq to prioritize an enhancer element located 120 kb upstream of the Ikzf1 gene. We found that deletion of the E120 enhancer resulted in a significant reduction of Ikzf1 mRNA. However, the epigenetic landscape and 3D topology of the locus were only slightly affected, highlighting the complexity of the regulatory landscape regulating the Ikzf1 locus.

Table S1. GO annotations for differentially expressed genes in male and female hearts after cecal ligation and puncture. Gene ontology analysis realized with the DAVID Database is reported in the table. The most significant biological processes (BP), cellular components (CC) and KEGG-pathways (KEGG) GO terms for up- and down-regulated genes are indicated for CLP vs sham groups in males and females. For all the processes, the number of genes deregulated in males is much greater than in females. N. of genes = Number of genes; NS = not significant; ø = not found. Table S2. GO annotations for differentially expressed genes in male and female hearts after landiolol administration. Gene ontology analysis realized with the DAVID Database is reported in the table. Significant biological processes (BP) and KEGG-pathway (KEGG) GO terms for up- and down-regulated genes are indicated for CLP plus landiolol vs CLP groups in males and females. For all the processes, the number of genes deregulated in males is much greater than in females and significant biological processes were totally absent for females after landiolol infusion. N. of genes = Number of genes; NS = not significant; ø = not found. (PPTX 51 kb)

International audience; Objectives: To investigate any gender effect of the beta-1 adrenergic blocker, landiolol, on cardiac performance and energy metabolism in septic rats, and to explore the expression of genes and proteins involved in this process.Design: Randomized animal study.Setting: University research laboratory.Subjects: Male and female Wistar rats.Interventions: One hour after cecal ligation and puncture, male and female rats were randomly allocated to the following groups: sham male, cecal ligation and puncture male, cecal ligation and puncture + landiolol male, sham female, cecal ligation and puncture female, and cecal ligation and puncture + landiolol female. Cardiac MRI was carried out 18 hours after cecal ligation and puncture to assess in vivo cardiac function. Ex vivo cardiac function measurement and 31P magnetic resonance spectroscopy were subsequently performed using an isovolumic isolated heart preparation. Finally, we assessed cardiac gene and protein expression.Measurements and Main Results: In males, landiolol increased indexed stroke volume by reversing the indexed end-diastolic volume reduction without affecting left ventricle ejection fraction. In females, landiolol did not increase indexed stroke volume and indexed end-diastolic volume but decreased left ventricle ejection fraction. Landiolol had no effect on ex vivo cardiac function and on high-energy phosphate compounds. The effect of landiolol on the gene expression of natriuretic peptide receptor 3 and on protein expression of phosphorylated-AKT:AKT ratio and endothelial nitric oxide synthase was different in males and females.Conclusions: Landiolol improved the in vivo cardiac performance of septic male rats while deleterious effects were reported in females. Expression of natriuretic peptide receptor 3, phosphorylated-AKT:AKT, and endothelial nitric oxide synthase are signaling pathways to investigate to better understand the sex differences in sepsis.

International audience; Linkage studies have revealed a linkage of mild malaria to chromosome 6p21 that contains the NCR3 gene encoding a natural killer cell receptor, whereas NCR3-412G>C (rs2736191) located in its promoter region was found to be associated with malaria in Burkina Faso. Here we confirmed the association of rs2736191 with mild malaria in a Congolese cohort and investigated its potential cis-regulatory effect. Luciferase assay results indicated that rs2736191-G allele had a significantly increased promoter activity compared to rs2736191-C allele. Furthermore, EMSAs demonstrated an altered binding of two nuclear protein complexes to the rs2736191-C allele in comparison to rs2736191-G allele. Finally, after in silico identification of transcription factor candidates, pull-down western blot experiments confirmed that both STAT4 and RUNX3 bind the region encompassing rs2736191 with a higher affinity for the G allele. To our knowledge, this is the first report that explored the functional role of rs2736191. These results support the hypothesis that genetic variation within natural killer cell receptors alters malaria resistance in humans.

Prospective sampling activities of intertidal invertebrates in the Ancon Bay (Lima, Peru) were done in order to select marine bacteria producing antimicrobial substances. The study included the isolation of bacteria in marine agar, in vitro antimicrobial susceptibility testing and electronic microscopic observations. We report the isolation, phenotypical characterization and antimicrobial properties of 10 strains of marine bacteria including the genus Vibrio, Pseudomonas, and Flavobacterium, and the order Actinomycetae that inhibit human pathogens. The results indicate that the marine invertebrates would be sources of bacteria producing antibiotic substances. Se realizó actividades prospectivas de muestreo de invertebrados intermareales en la Bahía de Ancón (Lima – Perú) con el objetivo de seleccionar bacterias marinas productoras de sustancias antimicrobianas. El estudio comprendió el aislamiento de bacterias en agar marino, pruebas de susceptibilidad antimicrobiana in vitro y observaciones de microscopía electrónica. Se reporta el aislamiento, caracterización fenotípica y propiedades antimicrobianas de diez cepas de bacterias marinas que incluyen a los géneros Vibrio, Pseudomonas y Flavobacterium y del orden Actinomycetal que inhiben a patógenos de humanos. Los resultados indicarían que los invertebrados marinos serían fuentes de bacterias productoras de sustancias antibióticas.