Dimethyloxalylglycine Promotes Bone Marrow Mesenchymal Stem Cell Osteogenesis via Rho/ROCK Signaling.

BACKGROUND/AIMS We investigated the role of dimethyloxalylglycine (DMOG) in bone marrow mesenchymal stem cell (BMSC) osteogenesis mediated by RhoA/ROCK. METHODS BMSCs were cultured with and without DMOG and/or Y-27632 (ROCK1 inhibitor). Cell proliferation, alkaline phosphatase (ALP) levels, and calcium deposits were determined. The expression of Runx2, OSX, p-cofilin, RhoA, and GTP-bound RhoA was determined by real-time RT-PCR and Western blot. Rho-associated coiled-coil-containing protein kinase (ROCK) activity was determined by measuring the phosphorylation of myosin-binding subunit of myosin phosphatase using an ELISA kit. Actin morphology was observed by immunofluorescence. RESULTS After 24 h, DMOG (0.5 mM) increased the expression of GTP-bound RhoA (+141%, P < 0.001) and enhanced ROCK activity (315%, P < 0.001). DMOG (0.5 mM) enhanced ALP levels after 3, 7, and 21 days of osteogenic induction (all P < 0.001) and strengthened calcium deposition (P < 0.001). In addition, compared with controls, DMOG (0.5 mM) increased the mRNA levels of osteogenesis genes RUNX2 and OSX (all P < 0.001). Furthermore, compared with controls, DMOG increased the expression of p-cofilin (+57%, P < 0.001), which resulted in rearrangement of actin filaments. All these effects were abolished, at least in part, by Y-27632. CONCLUSION DMOG promotes BMSC osteogenic differentiation via activation of RhoA/ROCK, suggesting clues for future therapies using BMSCs.