Genome wide association studies have identified significant association between polymorphisms of the Group 1B phospholipase A2 (PLA2G1B) gene with central obesity in humans. Previous studies have shown that Pla2g1b inactivation decreases postprandial lysophospholipid absorption and as a consequence increases hepatic fatty acid oxidation and protects against diet-induced obesity and glucose intolerance in mice. The current study showed that transgenic mice with pancreatic acinar cell-specific over-expression of the human PLA2G1B gene gained significantly more weight and displayed elevated insulin resistance characteristics, including impaired glucose tolerance, compared to wild type mice when challenged with a high fat/carbohydrate diet. Pre- and post-prandial plasma β-hydroxybutyrate levels were also lower, indicative of decreased hepatic fatty acid oxidation, in the hypercaloric diet-fed PLA2G1B transgenic mice. These, along with earlier observations of Pla2g1b-null mice, document that Pla2g1b expression level is an important determinant of susceptibility to diet-induced obesity and diabetes, suggesting that the relationship between PLA2G1B polymorphisms and obesity may be due to differences in PLA2G1B expression levels between these individuals. The ability of pancreas-specific over-expression of PLA2G1B to promote obesity and glucose intolerance suggests that target phospholipase activity in the digestive tract with nonabsorbable inhibitors should be considered as therapeutic option for metabolic disease therapy.
Keywords: Phospholipase A2, diet-induced obesity, diabetes, fatty acid oxidation