Group 1B phospholipase A₂ deficiency protects against diet-induced hyperlipidemia in mice

J Lipid Res. 2011 Nov;52(11):2005-11. doi: 10.1194/jlr.M019463. Epub 2011 Sep 9.

Abstract

Excessive absorption of products of dietary fat digestion leads to type 2 diabetes and other obesity-related disorders. Mice deficient in the group 1B phospholipase A₂ (Pla2g1b), a gut digestive enzyme, are protected against diet-induced obesity and type 2 diabetes without displaying dietary lipid malabsorption. This study tested the hypothesis that inhibition of Pla2g1b protects against diet-induced hyperlipidemia. Results showed that the Pla2g1b(-/-) mice had decreased plasma triglyceride and cholesterol levels compared with Pla2g1b(+/+) mice subsequent to feeding a high-fat, high-carbohydrate (hypercaloric) diet. These differences were evident before differences in body weight gains were observed. Injection of Poloxamer 407 to inhibit lipolysis revealed decreased VLDL production in Pla2g1b(-/-) mice. Supplementation with lysophosphatidylcholine, the product of Pla2g1b hydrolysis, restored VLDL production rates in Pla2g1b(-/-) mice and further elevated VLDL production in Pla2g1b(+/+) mice. The Pla2g1b(-/-) mice also displayed decreased postprandial lipidemia compared with Pla2g1b(+/+) mice. These results show that, in addition to dietary fatty acids, gut-derived lysophospholipids derived from Pla2g1b hydrolysis of dietary and biliary phospholipids also promote hepatic VLDL production. Thus, the inhibition of lysophospholipid absorption via Pla2g1b inactivation may prove beneficial against diet-induced hyperlipidemia in addition to the protection against obesity and diabetes.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animal Feed
  • Animals
  • Diet / adverse effects*
  • Diet, High-Fat / adverse effects
  • Dietary Carbohydrates / adverse effects
  • Dietary Supplements
  • Group IB Phospholipases A2 / deficiency*
  • Hyperlipidemias / blood
  • Hyperlipidemias / enzymology*
  • Hyperlipidemias / etiology*
  • Hyperlipidemias / metabolism
  • Lipoproteins, VLDL / biosynthesis
  • Lipoproteins, VLDL / blood
  • Liver / drug effects
  • Liver / metabolism
  • Lysophosphatidylcholines / pharmacology
  • Male
  • Mice
  • Postprandial Period / drug effects
  • Triglycerides / blood
  • Triglycerides / metabolism

Substances

  • Dietary Carbohydrates
  • Lipoproteins, VLDL
  • Lysophosphatidylcholines
  • Triglycerides
  • Group IB Phospholipases A2