The Role of Calcium in Differentiation of Human Adipose-Derived Stem Cells to Adipocytes

Abstract

Differentiation process of mesenchymal stem cells (MSCs) into adipocyte is involved in obesity. Multiple factors such as Ca2+ play important roles in different stages of this process. Because of the complicated roles of Ca2+ in adipogenesis, the aim of present investigation was to study the influx and efflux of Ca2+ into and out of the cells during adipogenesis. Adipose-derived MSCs were used to differentiate into adipocytes. MSCs were exposed to 2.5 mM Ca2+ or 1.8 mM Ca2+ plus calcium ionophore, A23187, for 3 days. Lipid staining, triglycerides (TG) content, and glyceraldehyde phosphate dehydrogenase (GAPDH) activity were evaluated to confirm the efficiency of the differentiation. Gene expression of GLUT4, PPAR gamma 2, RAR-alpha, and calreticulin, as well as the protein levels of GLUT4 and PPAR gamma 2 were determined. Ca2+ and in particular Ca2+ plus A23187 significantly lowered the efficiency of differentiation accompanied by decrease in intracellular TG deposits, GAPDH activity and alleviation of gene, and protein levels of GLUT4 and PPAR gamma 2. While calreticulin and RAR-alpha were remarkably upregulated in A23187 group. This study showed the inhibitory effects of calcium in adipogenesis. Additionally, it indicated the greater inhibitory effect of calreticulin and RAR-alpha in controlling adipogenesis by higher levels of calcium.