Postprandial lysophospholipid suppresses hepatic fatty acid oxidation: the molecular link between group 1B phospholipase A2 and diet-induced obesity

Decrease in fat catabolic rate on consuming a high-fat diet contributes to diet-induced obesity. This study used group 1B phospholipase A(2) (Pla2g1b)-deficient mice, which are resistant to hyperglycemia, to test the hypothesis that Pla2g1b and its lipolytic product lysophospholipid suppress hepatic fat utilization and energy metabolism in promoting diet-induced obesity. The metabolic consequences of hypercaloric diet, including body weight gain, energy expenditure, and fatty acid oxidation, were compared between Pla2g1b(+/+) and Pla2g1b(-/-) mice. The Pla2g1b(-/-) mice displayed normal energy balance when fed chow, but were resistant to obesity when challenged with a hypercaloric diet. Obesity resistance in Pla2g1b(-/-) mice is due to their ability to maintain elevated energy expenditure and core body temperature when subjected to hypercaloric diet, which was not observed in Pla2g1b(-/-) mice. The Pla2g1b(-/-) mice also displayed increased postprandial hepatic fat utilization due to increased expression of peroxisome proliferator-activated receptor (PPAR)-alpha, PPAR-delta, PPAR-gamma, cd36/Fat, and Ucp2, which coincided with reduced postprandial plasma lysophospholipid levels. Lysophospholipids produced by Pla2g1b hydrolysis suppress hepatic fat utilization and down-regulate energy expenditure, thereby preventing metabolically beneficial adaptation to a high-fat diet exposure in promoting diet-induced obesity and type 2 diabetes.-Labonte, E.D., Pfluger, P.T., Cash, J.G., Kuhel, D.G., Rojas, J.C., Magness, D.P., Jandacek, R.J., Tschop, M.H., Hui, D.Y. Postprandial lysophospholipid suppresses hepatic fatty acid oxidation: the molecular link between group 1B phospholipase A(2) and diet-induced obesity. FASEB J. 24, 2516-2524 (2010). www.fasebj.org