Contribution of microRNA-27b-3p to synovial fibrotic responses in knee osteoarthritis
Tavallaee G, Lively S, Rockel JS, Ali SA, Im M, Sarda C, Mitchell GM, Rossomacha E, Nakamura S, Potla P, Gabrial S, Matelski J, Ratneswaran A, Perry K, Hinz B, Gandhi R, Jurisica I, and Kapoor M. Contribution of microRNA-27b-3p to synovial fibrotic responses in knee osteoarthritis. Arthritis Rheumatol 2022.
OBJECTIVES: Synovial fibrosis contributes to osteoarthritis (OA) pathology but the underlying mechanisms remain unknown. We have observed increased microRNA (miR)-27b-3p levels in synovial fluid of late-stage radiographic knee OA patients. Here, we determined the contribution of miR-27b-3p to synovial fibrosis.
METHODS: Synovium sections obtained from Kellgren-Lawrence-graded knee OA patients and a mouse model of knee OA (destabilization of medial meniscus; DMM) were stained for miR-27b-3p using in situ hybridization. Effects of intra-articular injections of miR-27b-3p mimic into naïve mouse knee joints, and miR-27b-3p inhibitor in the DMM model were also examined. MiR-27b-3p mimic or inhibitor transfection experiments were performed on human OA fibroblast-like synoviocytes (FLS) using RT-qPCR array, RNA sequencing, RT-qPCR, Western blotting, immunofluorescence and migration assays.
RESULTS: MiR-27b-3p expression increased in the synovium of knee OA patients and after DMM surgery in mice. Intra-articular injections of miR-27b-3p mimic injected in mouse knee joints induced a synovial fibrosis-like phenotype with increased synovitis scores and increased COL1A1 and α-SMA expression. In the DMM model, miR-27b-3p inhibitor decreased α-SMA with unchanged COL1A1 expression and synovitis scores. MiR-27b-3p mimic treatment of human OA FLS induced pro-fibrotic responses including increased migration and expression of key extracellular matrix (ECM) genes, while inhibitor transfection had opposite effects. RNA-sequencing identified a PPARG/ADAMTS8 signaling axis regulated by miR-27b-3p in OA FLS. MiR-27b-3p mimic-transfected OA FLS treated with the PPARG agonist rosiglitazone or ADAMTS8-siRNA exhibited altered expression of select ECM genes.
CONCLUSIONS: This study demonstrates a key role of miR-27b-3p in ECM regulation associated with synovial fibrosis during OA.
ePub ahead of print