CYR61 調控骨型蛋白-2 (BMP-2) 致小鼠造骨細胞分化之探討

Abstract

Bone metabolism includes bone formation and reabsoption, which is executed and regulated by osteoblasts and osteoclasts. The dysregulation of these two types of cells would cause bone disorders. When healing, osteoblast migrates to the injury site and proceeds with differentiation process. According to the previous studies, bone morphogenetic protein-2 (BMP-2) may promote mesenchymal stem cells differentiated into bony structure. Cysteine rich protein (CYR61), a member of CCN family, regulates cell development, proliferation, migration, and differentiation. It’s been shown that CYR61 plays an important role in bone development and healing, and CYR61 is regulated by Wnt3A and promotes osteoblasts differentiation. While Wnt signaling pathway is crucial for BMP-2 to induce new bone formation, the regulation mechanism between CYR61 and BMP-2 in bone formation and differentiation is still unclear. Our current data showed that CYR61 significantly increased osteoblasts proliferation and migration in a dose-dependent manner, and increased mineralization in 14 days after treatment. Mechanistically, CYR61 enhanced bmp-2 mRNA and protein expression in time- and dose-dependent manners, and osteoblast migration, proliferation, and differentiation abilities were significantly inhibited by BMP-2 neutralizing antibody. Furthermore, we found that CYR61 induced BMP-2 expression through MAPK/Erk signal pathway. The use of pharmacological inhibitors revealed that ERK was involved in CYR61-mediated BMP-2 expression. Besides, we also showed that integrin alphavbeta3 neutralizing antibody could inhibit CYR61 activated ERK phosphorylation, BMP-2 protein expression, and osteoblast proliferation, migration, and differentiation. Taken together, our results provide evidence that rCYR61 up-regulates BMP-2 mRNA and protein expression, and promoted proliferation, migration, and differentiation through activation of ERK signaling pathway by binding to integrin alphavbeta3 receptor in preosteoblast-like cells.