A possible regulatory link between Twist 1 and PPARγ gene regulation in 3T3-L1 adipocytes

Background: Peroxisome proliferator-activated receptor. (PPAR gamma) is a critical gene that regulates the function of adipocytes. Therefore, studies on the molecular regulation mechanism of PPAR gamma are important to understand the function of adipose tissue. Twist 1 is another important functional gene in adipose tissue, and hundreds of genes are regulated by Twist 1. The aim of this study was to investigate the regulation of Twist 1 and PPAR gamma expression in 3T3-L1 mature adipocytes. Methods: We induced differentiation in 3T3-L1 preadipocytes and examined alterations in Twist 1 and PPAR gamma expression. We used the PPAR gamma agonist pioglitazone and the PPAR gamma antagonist T0070907 to investigate the effect of PPAR gamma on Twist 1 expression. In addition, we utilized retroviral interference and overexpression of Twist 1 to determine the effects of Twist 1 on PPAR gamma expression. Results: The expression levels of Twist 1 and PPAR gamma were induced during differentiation in 3T3-L1 adipocytes. Application of either a PPAR gamma agonist (pioglitazone) or antagonist (T0070907) influenced Twist 1 expression, with up-regulation of Twist 1 under pioglitazone (1 mu M, 24 h) and down-regulation of Twist 1 under T0070907 (100 mu M, 24 h) exposure. Furthermore, the retroviral interference of Twist 1 decreased the protein and mRNA expression of PPAR gamma, while Twist 1 overexpression had the opposite effect. Conclusions: There was a possible regulatory link between Twist 1 and PPAR gamma in 3T3-L1 mature adipocytes. This regulatory link enhanced the regulation of PPAR gamma and may be a functional mechanism of Twist 1 regulation of adipocyte physiology and pathology.