BMP9-regulated angiogenic signaling plays an important role in the osteogenic differentiation of mesenchymal progenitor cells.

ABSTRACT: Mesenchymal stromal progenitor cells (MSCs) are multipotent progenitors that can be isolated from numerous tissues. MSCs can undergo osteogenic differentiation under proper stimuli. We have recently demonstrated that bone morphogenetic protein 9 (BMP9) is one of the most osteogenic BMPs. As one of the least studied BMPs, BMP9 has been shown to regulate angiogenesis in endothelial cells. However, it is unclear whether BMP9-regulated angiogenic signaling plays any important role in the BMP9-initiated osteogenic pathway in MSCs. Here, we investigate the functional role of hypoxia-inducible factor 1? (HIF1?)-mediated angiogenic signaling in BMP9-regulated osteogenic differentiation of MSCs. We find that BMP9 induces HIF1? expression in MSCs through Smad1/5/8 signaling. Exogenous expression of HIF1? potentiates BMP9-induced osteogenic differentiation of MSCs both in vitro and in vivo. siRNA-mediated silencing of HIF1? or HIF1? inhibitor CAY10585 profoundly blunts BMP9-induced osteogenic signaling in MSCs. HIF1? expression regulated by cobalt-induced hypoxia also recapitulates the synergistic effect between HIF1? and BMP9 in osteogenic differentiation. Mechanistically, HIF1? is shown to exert its synergistic effect with BMP9 by inducing both angiogenic signaling and osteogenic signaling in MSCs. Thus, our findings should not only expand our understanding of the molecular basis behind BMP9-regulated osteoblastic lineage-specific differentiation, but also provide an opportunity to harness the BMP9-induced synergy between osteogenic and angiogenic signaling pathways in regenerative medicine.

SUBMITTER: Hu N 

PROVIDER: S-EPMC3613181 | biostudies-literature | 2013 Jan

REPOSITORIES: biostudies-literature