MOTS-c accelerates bone fracture healing by stimulating osteogenesis of bone marrow mesenchymal stem cells via positively regulating FOXF1 to activate the TGF-β pathway.

Abstract

To elucidate the function of MOTS-c in accelerating bone fracture healing by inducing BMSCs differentiation into osteoblasts, as well as its potential mechanism. Primary BMSCs were extracted from rats and induced for osteogenesis. The highest dose of MOTS-c that did not affect BMSCs proliferation was determined by CCK-8 assay. After 7-day osteogenesis, the relative levels of ALP, Bglap, and Runx2 in MOTS-c-treated BMSCs influenced by FOXF1 were examined. ALP staining and alizarin red S staining in BMSCs were performed as well. The interaction between FOXF1 and TGF-β was analyzed by ChIP assay. At last, rescue experiments were performed to uncover the role of FOXF1/TGF-β axis in MOTS-c-induced osteogenesis. 1 μM MOTS-c was the highest dose that did not affect BMSCs proliferation. MOTS-c treatment upregulated the relative levels of ALP, Bglap, and Runx2, and stimulated mineralization ability in BMSCs, which were attenuated by the silence of FOXF1. TGF-β was proved to interact with FOXF1, and its level was positively mediated by FOXF1. The silence of FOXF1 attenuated the accelerated osteogenesis and TGF-β upregulation in BMSCs because of MOTS-c induction, and these trends were further reversed by the overexpression of TGF-β. MOTS-c treatment markedly induces osteogenesis in BMSCs. During MOTS-c-induced osteogenic progression, the upregulated FOXF1 triggers the activation of TGF-β pathway, thus accelerating bone fracture healing.