NPC1 in human white adipose tissue and obesity

Background: Genetic studies have implicated the NPC1 gene (Niemann Pick type C1) in susceptibility to obesity. Methods: To assess the potential function of NPC1 in obesity, we determined its expression in abdominal white adipose tissue (WAT) in relation to obesity. NPC1 mRNA was measured by RT-qPCR in lean and obese individuals, paired samples of subcutaneous (sc) and omental (om) WAT, before and after weight loss, in isolated adipocytes and intact adipose pieces, and in primary adipocyte cultures during adipocyte differentiation. NPC1 protein was examined in isolated adipocytes. Results: NPC1 mRNA was significantly increased in obese individuals in scWAT and omWAT and downregulated by weight loss. NPC1 mRNA was enriched in isolated fat cells of WAT, in scWAT versus omWAT but not modified during adipocyte differentiation. NPC1 protein mirrored expression of mRNA in lean and obese individuals. Conclusions: NPC1 is highly expressed in human WAT adipocytes with increased levels in obese. These results suggest that NPC1 may play a role in adipocyte processes underlying obesity.