Novel osteogenetic therapy using BMP and small molecular compound (ROCK inhibitor)

点击翻译按钮获取中文摘要

There are multiple steps for osteogenesis from undifferentiated mesenchymal stem cells to osteoblast. These steps require longer period in the adult mammals (especially in monkey or human), and it becomes a big clinical problem. There is no available drug to stimulate the osteogenesis among the clinically approved medicines for the treatment of osteoporosis. One growth factor, named bone morphogenetic protein (BMP), is currently undertaken for the clinical trial for regeneration after surgery, however, the amount required for reasonable results in human is huge. In order to overcome these problems, our group has been screened small molecular compound, which stimulate osteogenesis by themselves or combination with BMP. We found three candidate compounds as follwing.1.Small GTP-binding protein-Rho-associated coiled-coil kinase (ROCK) inhibitor (Y-27632)2.Mitogen-activated protein kinase (MAP kinase) inhibitor (PD98059, U0126)3.Newly synthesized anti-rheumatic drug (T0614)We found that T0 … More 614 stimulated the expression of "osterix", key factor for ontogenesis, without affecting the expression of cbfa-1. In order to examine the mechanism for ROCK and MAP kinase inhibitor, we focused on the morphology of mesenchymal cells either treated with these inhibitors or transfected with various cDNAs of active/dominant negative forms of each kinase. We found that the actin cytoskeleton dynamics was dramatically changed by these treatments. Next we stimulated the preosteoblasts (MC3T3-E1 cells) with cytochalacin D or latrunculin B, which directly change the actin polymerization dynamics. Surprisingly, it revealed that most profound osteogenetic effect by BMP was observed when the cells were stimulated during the re-formation of focal adhesion after disappeared by the treatment with cytochalasin D or latrunculin B. These results suggest that regulation of actin dynamics itself effectively enhance the BMP-induced osteogenesis both in vitro and in vivo. We are currently studying the profound mechanism, and try to apply these results for clinical therapy. Less