Hypoxia is associated with a lower expression of genes involved in lipogenesis in visceral adipose tissue

Background: A key role for HIF-1 alpha in the promotion and maintenance of dietary obesity has been proposed. We analyzed the association between hypoxia and de novo lipogenesis in human adipose tissue. Methods: We studied HIF-1 alpha mRNA and protein expression in fasting status in visceral adipose tissue (VAT) from non-obese and morbidly obese subjects, and in VAT from wild-type and ob/ob C57BL6J mice in both fasting and feeding status. We also analyzed the effect of hypoxia on the VAT mRNA expression of genes involved in lipogenesis. Results: HIF-1 alpha was increased in VAT from morbidly obese subjects. In fasting status, C57BL6J ob/ob mice had a higher VAT HIF-1 alpha mRNA expression than C57BL6J wild-type mice. In feeding status, VAT HIF-1 alpha mRNA expression significantly increased in C57BL6J wild-type, but not in C57BL6J ob/ob mice. In humans, HIF-1 alpha mRNA expression correlated positively with body mass index and insulin resistance. VAT HIF-1 alpha mRNA expression correlated negatively with ACC1, PDHB and SIRT3 mRNA expression, and positively with PPAR-gamma. VAT explants incubated in hypoxia showed reduced SIRT3 and increased PPAR-gamma, SREBP-1c, ACLY, ACC1 and FASN mRNA expression. Conclusions: Morbidly obese subjects have a higher level of VAT HIF-1 alpha. Postprandial status is associated with an increase in HIF-1 alpha mRNA expression in C57BL6J wild-type mice. Hypoxia alters the mRNA expression of genes involved in de novo lipogenesis in human VAT.