Calcium Mobilization Inhibits Lipid Accumulation During the Late Adipogenesis via Suppression of PPARγ and LXRα Signalings

Calcium plays a role as a signaling molecule in various cellular events. It has been reported that calcium suppresses adipocyte differentiation only in the early phase of adipogenesis. Herein, we demonstrate that treatment of A23187, a mobilizer of intracellular calcium, on day 4 post adipocyte differentiation could still reduce lipid accumulation in differentiating 3T3- L1 cells for 48 h. In addition, luciferase reporter gene and RT-Q-PCR assays demonstrate that A23187 can selectively inhibit transcriptional activities and expression of PPARγ and LXRα, suggesting that A23187 may reduce lipid accumulation in the late phase of adipogenesis via downregulation of PPARγ and LXRα expression and transactivation. Moreover, inhibition of HDAC activity by trichostatin A (TSA) partially blocked A23187-mediated downregulation of transcriptional activities of PPARγ and LXRα. Together, our data demonstrate that calcium mobilization inhibits expression and transcriptional activities of PPARγ and LXRα, resulting in reduced lipid accumulation in differentiating adipocytes, and thus, mobilization of intracellular calcium in adipocytes may serve as a new preventive and therapeutic approach for obesity.