Human bone morphogenetic protein 9 (BMP-9), also known as growth differentiation factor 2 (GDF-2), is a transforming growth factorβ A member of the BMP subgroup of superfamily proteins that transmit signals through heterodimeric complexes composed of type I and type II BMP receptors. BMP-9 regulates the development and function of various embryonic and adult tissues. BMP-9 is synthesized and secreted by non parenchymal cells in the liver, which can promote lipid metabolism and inhibit glucose production. BMP-9 plays an important role in the development and maintenance of cholinergic neuronal phenotype in the embryonic central nervous system. BMP-9 also induces mesenchymal stem cells to differentiate into chondrocyte lines. At low concentrations, BMP-9 is a proliferation factor of hematopoietic progenitor cells; But at high concentrations, it promotes TGF -β The production of 1 inhibits the formation of blood progenitor cell colonies.