EFFECTS OF BMP-2, BMP-4, AND BMP-6 ON OSTEOBLASTIC DIFFERENTIATION OFBONE-MARROW-DERIVED STROMAL CELL-LINES, ST2 AND MC3T3-G2 PA6/

The effects of bone morphogenetic protein-2 (BMP-2) on osteoblastic di fferentiation of bone marrow stromal cells were investigated using two bone marrow stromal cell lines, ST2 and MC3T3-G2/PA6 (PA6). BMP-2 sti mulated ALP activity and induced parathyroid hormone (PTH)-dependent p roduction of cAMP in both ST2 and PA6 cells, but these effects were mo re apparent in ST2 cells than in PA6 cells. BMP-2 induced the producti on of osteocalcin in ST2 cells, but not in PA6 cells. BMP-4 and BMP-6 stimulated ALP activity in ST2 cells, but the effect of BMP-6 was less marked than that of BMP-2 and BMP-4. BMP-4 induced PTH-dependent cAMP production of cAMP in ST2 cells, but BMP-6 did not. When ST2 cells we re transplanted into the peritoneal cavities of athymic mice with BMP- 2 in diffusion chambers, these cells generated mineralized bone in the chambers. These results indicate that BMPs induce the differentiation of bone marrow stromal cells into osteoblasts. However, the effects d iffer among the BMPs and among the types of cell exposed to these prot eins. (C) 1996 Academic Press. Inc.