Enhanced mitochondrial biogenesis contributes to Wnt induced osteoblastic differentiation of C3H10T1/2 cells

Abstract Mitochondria play a key role in cell physiology including cell differentiation and proliferation. We investigated the changes of mitochondrial biogenesis during Wnt-induced osteoblastic differentiation of murine mesenchymal C3H10T1/2 cells. Scanning electron microscopy demonstrated that activation of Wnt signaling by Wnt-3A conditioned medicum (CM) resulted in significant increase in the number of mitochondria in C3H10T1/2 cells. In addition, the induction of alkaline phosphatase (ALP) activities by Wnt-3A CM was accompanied by significant increase in mitochondrial mass ( p p p p p  ≤ 0.05) and mtDNA copy number ( p 0 cells) was significantly suppressed both in basal and Wnt-3A stimulated state compared to those from mitochondria-intact cells (ρ + cells). As a mechanism for Wnt-mediated mitochondrial biogenesis, we found that Wnt increased the expression of PGC-1α, a critical molecules in mitochondrial biogenesis, through Erk and p38 MAPK pathway independent of β-catenin signaling. We also found that increased mitochondrial biogenesis is in turn positively regulating TOPflash reporter activity as well as β-catenin levels. To summarize, mitochodrial biogenesis is upregulated by Wnt signaling and this upregulation contributes to the osteoblastic differentiation of mouse mesenchymal C3H10T1/2 cells.