Relation between human LPIN1, hypoxia and endoplasmic reticulum stress genes in subcutaneous and visceral adipose tissue

Abstract

LPIN1 is the phosphatidic acid phosphatase that produces 1,2-diacylglycerol, and thus it is related to the synthesis of triglycerides in the adipocyte. LPIN1 has a role in lipid synthesis and nuclear receptor coactivation, both of which may be involved in lipid homeostasis and metabolism. Among others, hypoxia and endoplasmic reticulum (ER) stress are being shown to be related to the adipose dysfunction found in human obesity. The aim of this study was to analyze LPIN1 gene expression in human adipose tissue in parallel with several hypoxia, angiogenic, ER stress and peroxisome proliferator-activated receptor (PPAR)-related genes in human obesity. Gene expression was quantified in abdominal (subcutaneous and visceral) adipose tissue from 62 subjects. We have shown a marked association between LPIN1 and PPARalpha gene expression both in subcutaneous and visceral adipose tissues. Similarly, a strong interdependence with vascular endothelial growth factor (VEGF) gene expression was also described; in fact, LPIN1 and VEGF expression levels were significantly decreased with obesity to a similar extent. These associations might suggest a possible role of LPIN1 in stress conditions that occur in chronic obesity and underlie insulin resistance.