Integrative epigenomics in Sjögren´s syndrome reveals novel pathways and a strong interaction between the HLA, autoantibodies and the interferon signature

Primary Sjögren's syndrome (SS) is a systemic autoimmune disease characterized by lymphocytic infiltration and damage of exocrine salivary and lacrimal glands. The etiology of SS is complex with environmental triggers and genetic factors involved. By conducting an integrated multi-omics study, we confirmed a vast coordinated hypomethylation and overexpression effects in IFN-related genes, what is known as the IFN signature. Stratified and conditional analyses suggest a strong interaction between SS-associated HLA genetic variation and the presence of Anti-Ro/SSA autoantibodies in driving the IFN epigenetic signature and determining SS. We report a novel epigenetic signature characterized by increased DNA methylation levels in a large number of genes enriched in pathways such as collagen metabolism and extracellular matrix organization. We identified potential new genetic variants associated with SS that might mediate their risk by altering DNA methylation or gene expression patterns, as well as disease-interacting genetic variants that exhibit regulatory function only in the SS population. Our study sheds new light on the interaction between genetics, autoantibody profiles, DNA methylation and gene expression in SS, and contributes to elucidate the genetic architecture of gene regulation in an autoimmune population

O31 Integrative analysis reveals a molecular stratification of systemic autoimmune diseases

n/

Rôle de PKR dans la physiopathologie du lupus

Systemic lupus erythematosus is a heterogeneous autoimmune disease and understanding the physiopathology is necessary to improve treatments. In this work, we study the role of PKR in the lupus physiopathology. In fact, once activated, this protein produces interferon-α, the key cytokine of the disease. With our experiments, we show that PKR is overexpressed and spontaneously activated in lupus patients. We then show that the inhibition of PKR on blood cells of lupus patients induces an inhibition of the production of interferon-induced genes and immunoglobulins. We also show that 6-mercaptopurine, the active metabolite of azathioprine, a drug whose mechanism of action is not fully understood, is also a PKR inhibitor. Finally, a lupus murine model in which we inactivated PKR, shows that this protein plays a role in the differentiation of B cells producing autoantibodies that are pathogenic for the kidney. Our results are consistent with a key role of PKR in the physiopathology of the disease.(BIFA - Sciences biomédicales et pharmaceutiques) -- UCL, 201

STAT3 phosphorylation mediates the stimulatory effects of interferon alpha on B cell differentiation and activation in SLE.

OBJECTIVE: Type I IFNs play a well-known role in the pathogenesis of SLE, through activation of CD4 T and antigen-presenting cells. Here, we investigated the effects of IFN alpha (IFNα) on SLE B cell activation and differentiation. METHODS: Peripheral blood mononuclear cells (PBMCs) and purified total or naïve B cells were obtained from healthy controls and SLE patients. The effects of IFNα on B cell differentiation were studied by flow cytometry. The role of STAT3 in B cell responses to IFNα was studied using pharmacological inhibitors and PBMCs from STAT3-deficient individuals. RESULTS: Incubation of normal PBMCs with IFNα induces a B cell differentiation pattern as observed spontaneously in SLE PBMCs. IFNα displays direct stimulatory effects on purified naïve B cells from healthy individuals, as evidenced by a significant induction of cell surface CD38 and CD95 in the presence of the cytokine. In purified naïve B cells, IFNα also induces STAT3 phosphorylation. IFNα-induced naïve B cell differentiation in total PBMCs is significantly inhibited in the presence of STAT3 inhibitors, or in PBMCs from individuals with STAT3 loss of function mutations. Spontaneous levels of STAT3, but not STAT1, phosphorylation are significantly higher in total B cells from SLE patients compared with controls. Pharmacological STAT3 inhibition in SLE PBMCs inhibits naïve B cell activation and differentiation. CONCLUSION: IFNα displays direct stimulatory effects on B cell differentiation and activation in SLE. STAT3 phosphorylation mediates the effects of IFNα stimulation in naïve B cells, an observation that opens new therapeutic perspectives in SLE

Domácnosti v ČR: příjmy, spotřeba, úspory a dluhy v letech 1993 až 2012

Household final consumption expenditure and changes of the dynamics of individual components. Savings and debt. International comparison. Unconsumer attributes of the life

Intrarenal activation of adaptive immune effectors is associated with tubular damage and impaired renal function in lupus nephritis.

OBJECTIVES: Chronic renal impairment remains a feared complication of lupus nephritis (LN). The present work aimed at identifying mechanisms and markers of disease severity in renal tissue samples from patients with LN. METHODS: We performed high-throughput transcriptomic studies (Illumina HumanHT-12 v4 Expression BeadChip) on archived kidney biopsies from 32 patients with LN and eight controls (pretransplant donors). Histological staging (glomerular and tubular scores) and immunohistochemistry experiments were performed on the same and on a replication set of 37 LN kidney biopsy samples. RESULTS: A group of LN samples was identified by unsupervised clustering studies based on their gene expression features, that is, the overexpression of transcripts involved in antigen presentation, T and B cell activation. These samples were characterised by a significantly lower estimated glomerular filtration rate (eGFR) at the time of biopsy (T0) compared with the other systemic lupus erythematosus samples. Yet, apparent disease duration at T0, double-stranded DNA antibody titres at T0 and other relevant characteristics (serum C3, proteinuria, histological scores, numbers of previous flares) were not different between groups.Immunohistochemistry studies confirmed the association between interstitial infiltration by adaptive immune effectors and decreased renal function in the same and in a replication group of LN kidney biopsies. This was associated with transcriptomic, histological and immunohistochemical evidence of renal tubular cell involvement. CONCLUSION: Interstitial infiltration of LN kidney biopsies by adaptive immune effectors is associated with impaired renal tubular cell function and decreased eGFR. These results open new perspectives in evaluating and treating patients with LN, focusing on intrarenal mechanisms of immune cell activation

Toll-like receptor 3 increases antigen-presenting cell responses to a pro-apoptotic stimulus, yet does not contribute to systemic lupus erythematosus genetic susceptibility.

OBJECTIVES: TLR3 mediates skin solar injury by binding nuclear material released from apoptotic keratinocytes, resulting in the production of pro-inflammatory cytokines. Because the TLR3 gene is located in 4q35, a known systemic lupus erythematosus (SLE) susceptibility locus, we wondered whether TLR3 single nucleotide polymorphisms (SNPs) were associated with inflammatory mechanisms relevant to the development of SLE, and disease susceptibility. METHODS: Functional assays were carried out in TLR3-transfected HEK293 cells and in monocyte-derived dendritic cells (moDCs). TLR3 and IFNβ immunofluorescence studies were performed in skin samples from 7 SLE patients and 3 controls. We performed a SNP association study in a discovery cohort of 153 patients and 105 controls, followed by a confirmation study in an independent cohort of 1,380 patients and 2,104 controls. RESULTS: TLR3 and IFNβ are overexpressed in SLE skin lesions. TLR3 overexpression in HEK293 cells amplifies their sensitivity to a pro-apoptotic stimulus. Taking advantage of a naturally occurring polymorphic TLR3 variant (rs3775291) that weakly versus strongly responds to poly I:C stimulation, we found that TLR3 is associated with amplified apoptotic responses, production of the Ro/SSA autoantigen and increased maturation of myeloid-derived dendritic cells (moDC) after exposure to UV irradiation. However, TLR3 SNPs are not associated with susceptibility to SLE in a large population of patients and controls. CONCLUSIONS: TLR3 is overexpressed in SLE skin lesions and amplifies apoptotic and inflammatory responses to UV-irradiation in antigen-presenting cells in vitro. However, TLR3 SNPs do not impact susceptibility to the development of the disease

Integrative epigenomics in Sjögren´s syndrome reveals novel pathways and a strong interaction between the HLA, autoantibodies and the interferon signature

International audienceAbstract Primary Sjögren’s syndrome (SS) is a systemic autoimmune disease characterized by lymphocytic infiltration and damage of exocrine salivary and lacrimal glands. The etiology of SS is complex with environmental triggers and genetic factors involved. By conducting an integrated multi-omics study, we confirmed a vast coordinated hypomethylation and overexpression effects in IFN-related genes, what is known as the IFN signature. Stratified and conditional analyses suggest a strong interaction between SS-associated HLA genetic variation and the presence of Anti-Ro/SSA autoantibodies in driving the IFN epigenetic signature and determining SS. We report a novel epigenetic signature characterized by increased DNA methylation levels in a large number of genes enriched in pathways such as collagen metabolism and extracellular matrix organization. We identified potential new genetic variants associated with SS that might mediate their risk by altering DNA methylation or gene expression patterns, as well as disease-interacting genetic variants that exhibit regulatory function only in the SS population. Our study sheds new light on the interaction between genetics, autoantibody profiles, DNA methylation and gene expression in SS, and contributes to elucidate the genetic architecture of gene regulation in an autoimmune population

Machine learning identifies a common signature for anti-SSA/Ro60 antibody expression across autoimmune diseases.

International audienceAnti-Ro autoantibodies are among the most frequently detected extractable nuclear antigen autoantibodies, mainly associated with primary Sjögren's syndrome (pSS), systemic lupus erythematosus (SLE) and undifferentiated connective tissue disease (UCTD). Is there a common signature to all patients expressing anti-Ro60 autoantibodies regardless of their disease phenotype

A new molecular classification to drive precision treatment strategies in primary Sjogren's syndrome

There is currently no approved treatment for primary Sjogren's syndrome, a disease that primarily affects adult women. The difficulty in developing effective therapies is -in part- because of the heterogeneity in the clinical manifestation and pathophysiology of the disease. Finding common molecular signatures among patient subgroups could improve our understanding of disease etiology, and facilitate the development of targeted therapeutics. Here, we report, in a cross-sectional cohort, a molecular classification scheme for Sjogren's syndrome patients based on the multi-omic profiling of whole blood samples from a European cohort of over 300 patients, and a similar number of age and gender-matched healthy volunteers. Using transcriptomic, genomic, epigenetic, cytokine expression and flow cytometry data, combined with clinical parameters, we identify four groups of patients with distinct patterns of immune dysregulation. The biomarkers we identify can be used by machine learning classifiers to sort future patients into subgroups, allowing the re-evaluation of response to treatments in clinical trials. Sjogren's syndrome, a disease that primarily affects women, is poorly understood. Here, the authors combine data from a large cohort of patients and healthy controls to identify biomarkers that distinguish patient subgroups to improve our understanding of the disease and facilitate drug development