Intermittent fasting up-regulates Fsp27/Cidec gene expression in white adipose tissue

Objective: Fat-specific protein of 27 kDa (FSP27) is a novel lipid droplet protein that promotes triacylglycerol storage in white adipose tissue (WAT). The regulation of the Fsp27 gene expression in WAT is largely unknown. We investigated the nutritional regulation of FSP27 in WAT. Methods: The effects of intermittent fasting (48 d, eight cycles of 3-d fasting and 3-d refeeding), caloric restriction (48 d), fasting-refeeding (3-d fasting and 3-d refeeding), and fasting (3 d) on mRNA expression of FSP27, peroxisome proliferator-activated receptor gamma (PPAR gamma 2), CCAAT/enhancer binding protein alpha (C/EBP alpha), and M isoform of carnitine palmitoyltransferase 1 (a positive control for PPAR gamma activation) in epididymal WAT and on serum triacylglycerol, insulin, and leptin levels were determined in Wistar rats. We also determined the effects of PPAR gamma activation by rosiglitazone or pioglitazone on FSP27 mRNA levels in primary rat adipocytes. Results: Long-term intermittent fasting, in contrast to other dietary manipulations, significantly up-regulated Fsp27 gene expression in WAT. Moreover, in rats subjected to intermittent fasting, serum insulin levels were elevated; PPAR gamma 2 and C/EBP alpha mRNA expression in WAT was increased, and there was a positive correlation of Fsp27 gene expression with PPAR gamma 2 and C/EBP alpha mRNA levels. FSP27 mRNA expression was also increased in adipocytes treated with PPAR gamma agonists. Conclusion: our study demonstrates that the transcription of the Fsp27 gene in adipose tissue may be induced in response to nutritional stimuli. Furthermore, PPAR gamma 2, C/EBP alpha, and insulin may be involved in the nutritional regulation of FSP27. Thus intermittent fasting, despite lower caloric intake, may promote triacylglycerol deposition in WAT by increasing the expression of genes involved in lipid storage, such as Fsp27 (C) 2012 Elsevier Inc. All rights reserved.