Rheumatoid arthritis (RA) is a chronic inflammatory joint disease characterized by synovial hyperplasia. Mir204 and Mir211 are homologous miRNAs with the same gene targeting spectrum. It is known that Mir204/211 play an important role in protecting osteoarthritis development;
however, the roles of Mir204/211 in RA disease have not been determined. In the present study,
we investigated the effects and molecular mechanisms of Mir204/211 on synovial inflammation and
hyperproliferation in RA. The effects of Mir204/211 on the inflammation and abnormal proliferation
in primary fibroblast-like synoviocytes (FLSs) were examined by Mir204/211 gain-of-function and
loss-of-function approaches in vitro and in vivo. We... More
Rheumatoid arthritis (RA) is a chronic inflammatory joint disease characterized by synovial hyperplasia. Mir204 and Mir211 are homologous miRNAs with the same gene targeting spectrum. It is known that Mir204/211 play an important role in protecting osteoarthritis development;
however, the roles of Mir204/211 in RA disease have not been determined. In the present study,
we investigated the effects and molecular mechanisms of Mir204/211 on synovial inflammation and
hyperproliferation in RA. The effects of Mir204/211 on the inflammation and abnormal proliferation
in primary fibroblast-like synoviocytes (FLSs) were examined by Mir204/211 gain-of-function and
loss-of-function approaches in vitro and in vivo. We identified the structure-specific recognition
protein 1 (Ssrp1) as a downstream target gene of Mir204/211 based on the bioinformatics analysis.
We overexpressed Ssrp1and Mir204/211 in FLS to determine the relationship between Ssrp1 and
Mir204/211 and their effects on synovial hyperplasia. We created a collagen-induced arthritis (CIA)
model in wild-type as well as Mir204/211 double knockout (dKO) mice to induce RA phenotype and
administered adeno-associated virus (AAV)-mediated Ssrp1-shRNA (AAV-shSsrp1) by intra-articular
injection into Mir204/211 dKO mice. We found that Mir204/211 attenuated excessive cell proliferation and synovial inflammation in RA. Ssrp1 was the downstream target gene of Mir204/211.
Mir204/211 affected synovial proliferation and decelerated RA progression by targeting Ssrp1. CIA
mice with Mir204/211 deficiency displayed enhanced synovial hyperplasia and inflammation. RA
phenotypes observed in Mir204/211 deficient mice were significantly ameliorated by intra-articular
delivery of AAV-shSsrp1, confirming the involvement of Mir204/211-Ssrp1signaling during RA development. In this study, we demonstrated that Mir204/211 antagonize synovial hyperplasia and inflammation in RA by regulation of Ssrp1. Mir204/211 may serve as novel agents to treat RA disease.
