Project description:Synovial fibroblasts (SF) are the main mesenchymal cell type constitutive in human synovial tissue. SF contribute to the homeostasis of normal joints by synthesizing extracellular matrix components and secreting the specific components of synovial fluid. SF are essential players in RA pathophysiology, they are the primary source of IL6 in the RA synovium contributing to perpetuate the inflammation in the joint. We used microarrays analysis to characterize the effector pro-inflammatory response of SF to TNFα and IL6/sIL6R signaling.
Project description:Here we explored how the human macrophage response to tumor necrosis factor (TNF) is regulated by human synovial fibroblasts, the representative stromal cell type in the synovial lining of joints that become activated during inflammatory arthritis. Genome-wide transcriptome analysis (RNAseq) showed that co-cultured synovial fibroblasts modulate the expression of approximately one third of TNF-inducible genes in macrophages, including expression of target genes in pathways important for macrophage survival and polarization towards an alternatively activated phenotype. This work furthers our understanding of the interplay between innate immune and stromal cells during an inflammatory response, one that is particularly relevant to inflammatory arthritis. Our findings also identify modulation of macrophage phenotype as a new function for synovial fibroblasts that may prove to be a contributing factor in arthritis pathogenesis.
Project description:IntroductionThe clinical efficacy of specific interleukin-6 inhibitors has confirmed the central role of IL6 in rheumatoid arthritis (RA). However the local role of IL6, in particular in synovial fibroblasts (SF) as a direct cellular target to IL6/sIL6R signal is not well characterized. The purpose of the study was to characterize the crosstalk between TNFα and IL6/sIL6R signaling to the effector pro-inflammatory response of SF.MethodsSF lines were stimulated with either TNFα, IL6/sIL6R, or both together, for the time and dose indicated for each experiment, and where indicated, cells were treated with inhibitors actinomycin D, adalimumab, ruxolitinib and cycloheximide. mRNA expression of cytokines, chemokines and matrix metalloproteases (MMPs) were analyzed by quantitative RT-PCR. Level of IL8/CXCL8 and CCL8 in culture supernatants was measured by ELISA. Mononuclear and polymorphonuclear cells migration assays were assessed by transwell using conditioned medium from SF cultures. Statistical analyses were performed as indicated in the corresponding figure legends and a p-value < 0.05 was considered statistically significant.ResultsThe stimulation of SF with IL6/sIL6R and TNFα, cooperatively promotes the expression of mono- and lymphocytic chemokines such as IL6, CCL8 and CCL2, as well as matrix degrading enzymes such as MMP1, while inhibiting the induction of central neutrophil chemokines such as IL8/CXCL8. These changes in the pattern of chemokines expression resulted in reduced polymorphonuclear (PMN) and increased mononuclear cells (MNC) chemoattraction by SF. Mechanistic analyses of the temporal expression of genes demonstrated that the cooperative regulation mediated by these two factors is mostly induced through de novo transcriptional mechanisms activated by IL6/sIL6R. Furthermore, we also demonstrate that TNFα and IL6/sIL6R cooperation is partially mediated by the expression of secondary factors signaling through JAK/STAT pathways.ConclusionsThese results point out to a highly orchestrated response to IL6 in TNFα-induced SF and provide additional insights into the role of IL6/sIL6R in the context of RA, highlighting the contribution of IL6/sIL6R to the interplay of SF with other inflammatory cells.
Project description:Here we explored how the human macrophage response to tumor necrosis factor (TNF) is regulated by human synovial fibroblasts, the representative stromal cell type in the synovial lining of joints that become activated during inflammatory arthritis. Genome-wide transcriptome analysis (RNAseq) showed that co-cultured synovial fibroblasts modulate the expression of approximately one third of TNF-inducible genes in macrophages, including expression of target genes in pathways important for macrophage survival and polarization towards an alternatively activated phenotype. This work furthers our understanding of the interplay between innate immune and stromal cells during an inflammatory response, one that is particularly relevant to inflammatory arthritis. Our findings also identify modulation of macrophage phenotype as a new function for synovial fibroblasts that may prove to be a contributing factor in arthritis pathogenesis. Human CD14+ MCSF-differentiated macrophages were cultured with or without synovial fibroblasts in transwell chambers. TNF was added at Day 0, macrophages were harvested at Day 2. Total of 4 samples: (1) macrophages alone (2) macrophages with fibroblasts (3) macrophages with TNF (4) macrophages with fibroblasts and TNF. Macrophage RNA was purified using RNeasy mini kit (Qiagen). Tru-seq sample preparation kits (Illumina) were used to purify poly-A transcripts and generate libraries with multiplexed barcode adaptors. All samples passed quality control on a Bioanalyzer 2100 (Agilent). Paired-end reads (50 x 2 cycles, ~75x106 reads per sample) were obtained on an Illumina HiSeq 2500. The TopHat program was used to align the reads to the UCSC Hg19 human reference genome, while the Cufflinks program allowed for measurements of transcript abundance (represented by Fragments Per Kilobase of exon model per Million mapped reads (FPKM)).
Project description:To investigate the effects of soluble factors produced by synovial CD8 T cells, we stimulated human rheumatoid arthritis (RA) synovial fibroblasts with supernatants from synovial fluid CD8 T cells, blood CD8 T cells, or synovial fluid CD4 T cells stimulated with anti-CD3/CD28 antibody-coated beads. For comparison, we stimulated RA synovial fibroblasts with recombinant TNF or interferon-gamma or T cell supernatants pre-incubated with TNF-blocking antibodies.
Project description:mRNA expression levels in synovial fibroblasts in 6 rheumatoid arthritis patients versus 6 osteoarthritis patients. Keywords: disease type comparison, mRNA expression study
Project description:Inflammatory tissues are characterized by low oxigen concentrations (hypoxia). These conditions are very different from that usually present in tissue cultures where transcriptomic profiles of human fibroblasts from inflammatory tissues have been previously analysed. The aim of this study was to characterize the changes on gene expression induced by hypoxia in human synovial fibroblasts. We used microarray expression profiling in paired normoxic and hypoxic cultures of healthy and rheumatoid arthritis (RA) synovial fibroblasts (HSF and RASF). Hypoxia induces significant changes on the expression of large groups of genes in both HSF and RASF. The hypoxic and normoxic profiles are also different between both groups. These data demonstrate that hypoxia induces significant changes on gene expression in HSF and RASF and identify differences between RASF and HSF.