Small RNA sequencing of exosomes derived from MH7A synovial fibroblast cell line with TNF-α stimulation. Homo sapiens isolate:MH7A

Rheumatoid arthritis (RA) is an autoimmune disease causing chronic inflammation in joints. A central part of the RA pathogenesis is carried out by intercellular communication containing synovial fibroblasts. Here, we tried to identify primarily exosomal miRNAs derived from synovial fibroblasts in order to better understand the intercellular communication involving to the RA pathogenesis. Exosomes were collected from a RA synovial fibroblasts (RASF) cell line, MH7A, with or without stimulation by tumor necrosis factor-α (TNF-α). We used small RNA-Seq to analyze the profile of small RNAs including microRNAs (miRNAs) in MH7A exosomes and cells. With differential expression analysis, we identified that four miRNAs (miR-155-5p, miR-146a-5p, miR-323a-5p, and miR-1307-3p) were upregulated in exosomes with TNF-α stimulation. Identification of miR-155-5p and miR-146a-5p which have been reported to involve in RA patients suggested the validity of our experimental model. miR-323a-5p was predicted to target CD6 which attenuated T cell activation signals, and miR-1307-3p was predicted to target N-myc downstream-regulated gene 2 protein (NDRG2) which inhibited expression of osteoclast-related genes. Accordingly, it suggested these miRNAs might involve to the RA pathogenesis. Our results will assist in understanding the function of RASF exosomes in RA pathogenesis.