RhoA Promotes Synovial Proliferation and Bone Erosion in Rheumatoid Arthritis through Wnt/PCP Pathway.

Ras homolog gene family member A (RhoA) plays a major role in the Wnt/planar cell polarity (PCP) pathway, which is significantly activated in patients with rheumatoid arthritis (RA). The function of RhoA in RA synovitis and bone erosion is still elusive. Here, we not only explored the impact of RhoA on the proliferation and invasion of RA fibroblast-like synoviocytes (FLSs) but also elucidated its effect on mouse osteoclast and a mouse model of collagen-induced arthritis (CIA). Results showed that RhoA was overexpressed in RA and CIA synovial tissues. Lentivirus-mediated silencing of RhoA increased apoptosis, attenuated invasion, and dramatically upregulated osteoprotegerin/receptor activator of nuclear factor-κB ligand (OPG/RANKL) ratio in RA-FLSs. Additionally, the silencing of RhoA inhibited mouse osteoclast differentiation in vitro and alleviated synovial hyperplasia and bone erosion in the CIA mouse model. These effects in RA-FLSs and osteoclasts were all regulated by RhoA/Rho-associated protein kinase 2 (ROCK2) and might interact with Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathways.

[MicroRNAs in microglia polarization and CNS diseases: mechanism and functions].

Microglia are resident macrophages of central nervous system (CNS), and thus act as the crucial stuff of immune response and play very important roles in the progress of various CNS diseases. There are two different polarization statuses of activated microglia, M1 and M2 phenotypes. M1 polarized microglia are important for eradicating bacterial and promoting inflammation, whereas M2 cells are characterized by anti-inflammation and tissue remodeling. Recently, more and more evidence indicated that different polarized microglia showed diverse microRNA (miRNA) expression profiles. MiRNAs regulate microglia polarization, and thus affect the progress of CNS diseases. Fully exploring the polarization status of microglia during CNS diseases and the role of miRNAs in microglia polarization will be very helpful for a deep understanding of the roles of microglia in immunopathologic mechanism of different CNS diseases and offer the theoretical foundation of searching more effective therapies for these disorders.