Although the role of glycogen synthase kinase 3â (GSK3â) in osteogenic differentiation of bone marrow-derived mesenchymal stromal cells (BMSCs) is well-characterized as a negative regulator of â-catenin, its effect on osteogenesis of adipose-derived stromal cells (ADSCs) is poorly understood. Here, we show that GSK3â positively regulates osteogenic differentiation of murine ADSCs. Gain-of-function studies showed that GSK3â promotes in vitro osteogenesis of ADSCs. Regulation of GSK3â activity in ADSCs, either by small interfering RNA (siRNA)-mediated GSK3â silencing or by pharmacological inhibitors, blunted osteogenesis and the expression of osteogenic markers. Importantly, we demonstrated that transgenic mice, engineered to overexpress the constitutively active GSK3â (GSK3â-S9A) mutant, exhibited a marked increase in osteogenesis, whereas expression of the catalytically inactive GSK3â (GSK3â-K85A) in mice inhibits osteogenic differentiation. Molecular analyses showed that the enhanced osteoblast differentiation induced by GSK3â was mediated by downregulation of â-catenin. Remarkably, â-catenin silencing enhances osteogenesis and osteoblast marker gene expression such as alkaline phosphatase (ALP) and osterix. Taken together, these findings demonstrate a novel role for GSK3â in the regulation of osteogenic differentiation in ADSCs.
Adipocytes Animals