Impaired osteoclastogenesis by miR-31 inhibition is mediated by increased RhoA activity. (A) Western blot analysis of osteoclasts after retroviral transduction of pSmiR31 or pScontrol. Expression of RhoA protein was increased in pSmiR31 transduced osteoclasts. (B) RhoA activity was also increased by miR-31 inhibition. Values were normalized to RhoA activity of bone marrow macrophages (BMMs) (n = 3/group. **P < 0.01. (C) Western blot analysis of osteoclasts. Expression of c-Src and Pyk2 protein were not altered in pSmiR31 transduced osteoclasts. (D), (E) Osteoclasts were induced in the presence of the RhoA inhibitor; exoenzyme C3. A low concentration of exoenzyme C3 rescued the decreased number of ring-shaped tartrate-resistant acid phosphatase (TRAP)-positive MNCs caused by miR-31 inhibition (n = 3/group). **P < 0.01. MNCs, multinucleated cells.
Mizoguchi et al. Arthritis Research & Therapy 2013 15:R102 doi:10.1186/ar4282