Wasl is crucial to maintain microglial core activities during glioblastoma initiation stages

Microglia actively promotes the growth of high‐grade gliomas. Within the glioma microenvironment an amoeboid microglial morphology has been observed, however the underlying causes and the related impact on microglia functions and their tumor promoting activities is unclear. Using the advantages of the larval zebrafish model, we identified the underlying mechanism and show that microglial morphology and functions are already impaired during glioma initiation stages. The presence of pre‐neoplastic HRasV12 expressing cells induces an amoeboid morphology of microglia, increases microglial numbers and decreases their motility and phagocytic activity. RNA sequencing analysis revealed lower expression levels of the actin nucleation promoting factor wasla in microglia. Importantly, a microglia specific rescue of wasla expression restores microglial morphology and functions. This results in increased phagocytosis of pre‐neoplastic cells and slows down tumor progression. In conclusion, we identified a mechanism that de‐activates core microglial functions within the emerging glioma microenvironment. Restoration of this mechanism might provide a way to impair glioma growth

Evidence After Imputation for a Role of MICA Variants in Nonprogression and Elite Control of HIV Type 1 Infection

Past genome-wide association studies (GWAS) involving individuals with AIDS have mainly identified associations in the HLA region. Using the latest software, we imputed 7 million single-nucleotide polymorphisms (SNPs)/indels of the 1000 Genomes Project from the GWAS-determined genotypes of individuals in the Genomics of Resistance to Immunodeficiency Virus AIDS nonprogression cohort and compared them with those of control cohorts. The strongest signals were in MICA, the gene encoding major histocompatibility class I polypeptide-related sequence A (P = 3.31 × 10−12), with a particular exonic deletion (P = 1.59 × 10−8) in full linkage disequilibrium with the reference HCP5 rs2395029 SNP. Haplotype analysis also revealed an additive effect between HLA-C, HLA-B, and MICA variants. These data suggest a role for MICA in progression and elite control of human immunodeficiency virus type 1 infectio

Gene expression profiling reveals a conserved microglia signature in larval zebrafish

International audienceMicroglia are the resident macrophages of the brain. Over the past decade, our understanding of the function of these cells has significantly improved. Microglia do not only play important roles in the healthy brain but are involved in almost every brain pathology. Gene expression profiling allowed to distinguish microglia from other macro-phages and revealed that the full microglia signature can only be observed in vivo. Thus, animal models are irreplaceable to understand the function of these cells. One of the popular models to study microglia is the zebrafish larva. Due to their optical transparency and genetic accessibility, zebrafish larvae have been employed to understand a variety of microglia functions in the living brain. Here, we performed RNA sequencing of larval zebrafish microglia at different developmental time points: 3, 5, and 7 days post fertilization (dpf). Our analysis reveals that larval zebrafish microglia rapidly acquire the core microglia signature and many typical microglia genes are expressed from 3 dpf onwards. The majority of changes in gene expression happened between 3 and 5 dpf, suggesting that differentiation mainly takes place during these days. Furthermore, we compared the larval microglia transcriptome to published data sets of adult zebrafish microglia, mouse microglia, and human microglia. Larval microglia shared a significant number of expressed genes with their adult counterparts in zebrafish as well as with mouse and human microglia. In conclusion, our results show that larval zebrafish microglia mature rapidly and express the core microglia gene signature that seems to be conserved across species. K E Y W O R D S brain, evolution, microglia, RNA sequencing, transcriptome, zebrafis

Gene expression profiling reveals a conserved microglia signature in larval zebrafish

Microglia are the resident macrophages of the brain. Over the past decade, our understanding of the function of these cells has significantly improved. Microglia do not only play important roles in the healthy brain but are involved in almost every brain pathology. Gene expression profiling allowed to distinguish microglia from other macrophages and revealed that the full microglia signature can only be observed in vivo. Thus, animal models are irreplaceable to understand the function of these cells. One of the popular models to study microglia is the zebrafish larva. Due to their optical transparency and genetic accessibility, zebrafish larvae have been employed to understand a variety of microglia functions in the living brain. Here, we performed RNA sequencing of larval zebrafish microglia at different developmental time points: 3, 5, and 7 days post fertilization (dpf). Our analysis reveals that larval zebrafish microglia rapidly acquire the core microglia signature and many typical microglia genes are expressed from 3 dpf onwards. The majority of changes in gene expression happened between 3 and 5 dpf, suggesting that differentiation mainly takes place during these days. Furthermore, we compared the larval microglia transcriptome to published data sets of adult zebrafish microglia, mouse microglia, and human microglia. Larval microglia shared a significant number of expressed genes with their adul

The HLA-B*57:01 allele corresponds to a very large MHC haploblock likely explaining its massive effect for HIV-1 elite control

IntroductionWe have reanalyzed the genomic data of the International Collaboration for the Genomics of HIV (ICGH), centering on HIV-1 Elite Controllers.MethodsWe performed a genome-wide Association Study comparing 543 HIV Elite Controllers with 3,272 uninfected controls of European descent. Using the latest database for imputation, we analyzed 35,552 Single Nucleotide Polymorphisms (SNPs) within the Major Histocompatibility Complex (MHC) region.ResultsOur analysis identified 2,626 SNPs significantly associated (p<5. 10-8) with elite control of HIV-1 infection, including well-established MHC signals such as the rs2395029-G allele which tags HLA-B*57:01. A thorough investigation of SNPs in linkage disequilibrium with rs2395029 revealed an extensive haploblock spanning 1.9 megabases in the MHC region tagging HLA-B*57:01, comprising 379 SNP alleles impacting 72 genes. This haploblock contains damaging variations in proteins like NOTCH4 and DXO and is also associated with a strong differential pattern of expression of multiple MHC genes such as HLA-B, MICB, and ZBTB12. The study was expanded to include two cohorts of seropositive African-American individuals, where a haploblock tagging the HLA-B*57:03 allele was similarly associated with control of viral load. The mRNA expression profile of this haploblock in African Americans closely mirrored that in the European cohort.DiscussionThese findings suggest that additional molecular mechanisms beyond the conventional antigen-presenting role of class I HLA molecules may contribute to the observed influence of HLA-B*57:01/B*57:03 alleles on HIV-1 elite control. Overall, this study has uncovered a large haploblock associated with HLA-B*57 alleles, providing novel insights into their massive effect on HIV-1 elite control

HLA-DRB1 and HLA-DQB1 genetic diversity modulates response to lithium in bipolar affective disorders

Bipolar afective disorder (BD) is a severe psychiatric illness, for which lithium (Li) is the gold standard for acute and maintenance therapies. The therapeutic response to Li in BD is heterogeneous and reliable biomarkers allowing patients stratifcation are still needed. A GWAS performed by the International Consortium on Lithium Genetics (ConLiGen) has recently identifed genetic markers associated with treatment responses to Li in the human leukocyte antigens (HLA) region. To better understand the molecular mechanisms underlying this association, we have genetically imputed the classical alleles of the HLA region in the European patients of the ConLiGen cohort. We found our best signal for amino-acid variants belonging to the HLA-DRB1*11:01 classical allele, associated with a better response to Li (p < 1 × ­10−3; FDR< 0.09 in the recessive model). Alanine or Leucine at position 74 of the HLA-DRB1 heavy chain was associated with a good response while Arginine or Glutamic acid with a poor response. As these variants have been implicated in common infammatory/autoimmune processes, our fndings strongly suggest that HLA-mediated low infammatory background may contribute to the efcient response to Li in BD patients, while an infammatory status overriding Li anti-infammatory properties would favor a weak response

Distinct Genetic Loci Control Plasma HIV-RNA and Cellular HIV-DNA Levels in HIV-1 Infection: The ANRS Genome Wide Association 01 Study

Previous studies of the HIV-1 disease have shown that HLA and Chemokine receptor genetic variants influence disease progression and early viral load. We performed a Genome Wide Association study in a cohort of 605 HIV-1-infected seroconverters for detection of novel genetic factors that influence plasma HIV-RNA and cellular HIV-DNA levels. Most of the SNPs strongly associated with HIV-RNA levels were localised in the 6p21 major histocompatibility complex (MHC) region and were in the vicinity of class I and III genes. Moreover, protective alleles for four disease-associated SNPs in the MHC locus (rs2395029, rs13199524, rs12198173 and rs3093662) were strikingly over-represented among forty-five Long Term HIV controllers. Furthermore, we show that the HIV-DNA levels (reflecting the HIV reservoir) are associated with the same four SNPs, but also with two additional SNPs on chromosome 17 (rs6503919; intergenic region flanked by the DDX40 and YPEL2 genes) and chromosome 8 (rs2575735; within the Syndecan 2 gene). Our data provide evidence that the MHC controls both HIV replication and HIV reservoir. They also indicate that two additional genomic loci may influence the HIV reservoir

Analyses ‘genome entier’ de la cohorte griv de patients à profil extrême du sida

After 25 years of intensive research, no vaccine or cure exists against AIDS, and the molecular mechanisms of pathogenesis of HIV-1 infection are not clearly understood. Technological progress has made possible to compare cases versus controls over the whole genome. It is thus possible to identify genes potentially involved in disease development with no a priori, and consequently develop rationally new diagnostic or therapeutic strategies.During my PhD, I have completed two genome-wide association studies (GWAS) in AIDS, comparing 275 long term non-progressors or the 85 rapid progressors from the GRIV cohort with a cohort of seronegative controls. I have also completed a third analysis exploiting data from three international GWAS including ours (France, Netherlands, USA), targeting particularly low frequency SNPs (minor allele frequency, MAF <5%). These GWAS approaches have reaffirmed the central role of HLA for progression towards AIDS, but also revealed new relevant candidate genes, shedding a new light on the molecular mechanisms of disease progression.Après 25 ans de recherche intensive, aucun vaccin ou traitement définitif contre le SIDA n'existe, et les mécanismes moléculaires de pathogenèse de l'infection VIH-1 ne sont pas clairement élucidés. Les avancées technologiques permettent de comparer des sujets malades avec des sujets contrôles sur tout le génome. Il est ainsi possible d’identifier sans a priori des gènes potentiellement impliqués dans le développement de la maladie avec pour conséquence le développement rationnel de nouvelles stratégies diagnostiques ou thérapeutiques. Durant ma thèse, j’ai réalisé deux études d’association ‘génome entier’ dans le SIDA, en comparant les 275 non-progresseurs à long terme ou les 85 progresseurs rapides de la cohorte GRIV avec une cohorte de contrôles séronégatifs. J’ai réalisé une troisième analyse en exploitant les données issues de trois études ‘génome entier’ internationales dont la nôtre (France, Pays-Bas, USA), ciblant plus particulièrement les SNPs de fréquence faible (fréquence de l’allèle mineur, MAF<5%). Ces approches ‘génome entier’ ont réaffirmé le rôle central du HLA dans la progression vers le SIDA, mais aussi dévoilé de nouveaux gènes candidats très pertinents donnant une nouvelle lumière sur les mécanismes moléculaires de la maladie

Genome wide association study of patients from the GRIV cohort with extreme AIDS phenotypes

Après 25 ans de recherche intensive, aucun vaccin ou traitement définitif contre le SIDA n'existe, et les mécanismes moléculaires de pathogenèse de l'infection VIH-1 ne sont pas clairement élucidés. Les avancées technologiques permettent de comparer des sujets malades avec des sujets contrôles sur tout le génome. Il est ainsi possible d’identifier sans a priori des gènes potentiellement impliqués dans le développement de la maladie avec pour conséquence le développement rationnel de nouvelles stratégies diagnostiques ou thérapeutiques. Durant ma thèse, j’ai réalisé deux études d’association ‘génome entier’ dans le SIDA, en comparant les 275 non-progresseurs à long terme ou les 85 progresseurs rapides de la cohorte GRIV avec une cohorte de contrôles séronégatifs. J’ai réalisé une troisième analyse en exploitant les données issues de trois études ‘génome entier’ internationales dont la nôtre (France, Pays-Bas, USA), ciblant plus particulièrement les SNPs de fréquence faible (fréquence de l’allèle mineur, MAF<5%). Ces approches ‘génome entier’ ont réaffirmé le rôle central du HLA dans la progression vers le SIDA, mais aussi dévoilé de nouveaux gènes candidats très pertinents donnant une nouvelle lumière sur les mécanismes moléculaires de la maladie.After 25 years of intensive research, no vaccine or cure exists against AIDS, and the molecular mechanisms of pathogenesis of HIV-1 infection are not clearly understood. Technological progress has made possible to compare cases versus controls over the whole genome. It is thus possible to identify genes potentially involved in disease development with no a priori, and consequently develop rationally new diagnostic or therapeutic strategies. During my PhD, I have completed two genome-wide association studies (GWAS) in AIDS, comparing 275 long term non-progressors or the 85 rapid progressors from the GRIV cohort with a cohort of seronegative controls. I have also completed a third analysis exploiting data from three international GWAS including ours (France, Netherlands, USA), targeting particularly low frequency SNPs (minor allele frequency, MAF <5%). These GWAS approaches have reaffirmed the central role of HLA for progression towards AIDS, but also revealed new relevant candidate genes, shedding a new light on the molecular mechanisms of disease progression

Analyses ‘genome entier’ de la cohorte griv de patients à profil extrême du sida

After 25 years of intensive research, no vaccine or cure exists against AIDS, and the molecular mechanisms of pathogenesis of HIV-1 infection are not clearly understood. Technological progress has made possible to compare cases versus controls over the whole genome. It is thus possible to identify genes potentially involved in disease development with no a priori, and consequently develop rationally new diagnostic or therapeutic strategies.During my PhD, I have completed two genome-wide association studies (GWAS) in AIDS, comparing 275 long term non-progressors or the 85 rapid progressors from the GRIV cohort with a cohort of seronegative controls. I have also completed a third analysis exploiting data from three international GWAS including ours (France, Netherlands, USA), targeting particularly low frequency SNPs (minor allele frequency, MAF <5%). These GWAS approaches have reaffirmed the central role of HLA for progression towards AIDS, but also revealed new relevant candidate genes, shedding a new light on the molecular mechanisms of disease progression.Après 25 ans de recherche intensive, aucun vaccin ou traitement définitif contre le SIDA n'existe, et les mécanismes moléculaires de pathogenèse de l'infection VIH-1 ne sont pas clairement élucidés. Les avancées technologiques permettent de comparer des sujets malades avec des sujets contrôles sur tout le génome. Il est ainsi possible d’identifier sans a priori des gènes potentiellement impliqués dans le développement de la maladie avec pour conséquence le développement rationnel de nouvelles stratégies diagnostiques ou thérapeutiques. Durant ma thèse, j’ai réalisé deux études d’association ‘génome entier’ dans le SIDA, en comparant les 275 non-progresseurs à long terme ou les 85 progresseurs rapides de la cohorte GRIV avec une cohorte de contrôles séronégatifs. J’ai réalisé une troisième analyse en exploitant les données issues de trois études ‘génome entier’ internationales dont la nôtre (France, Pays-Bas, USA), ciblant plus particulièrement les SNPs de fréquence faible (fréquence de l’allèle mineur, MAF<5%). Ces approches ‘génome entier’ ont réaffirmé le rôle central du HLA dans la progression vers le SIDA, mais aussi dévoilé de nouveaux gènes candidats très pertinents donnant une nouvelle lumière sur les mécanismes moléculaires de la maladie