An inhibitor of phospholipase A2 group IIA modulates adipocyte signaling and protects against diet-induced metabolic syndrome in rats.

Abstract

Obesity, type 2 diabetes, and cardiovascular disease correlate with infiltration to adipose tissue of different immune cells, with uncertain influences on metabolism. Rats were fed a diet high in carbohydrates and saturated fats to develop diet-induced obesity over 16 weeks. This nutritional overload caused overexpression and secretion of phospholipase A(2) group IIA (pla2g2a) from immune cells in adipose tissue rather than adipocytes, whereas expression of adipose-specific phospholipase A(2) (pla2g16) was unchanged. These immune cells produce prostaglandin E(2) (PGE(2)), which influences adipocyte signaling. We found that a selective inhibitor of human pla2g2a (5-(4-benzyloxyphenyl)-(4S)-(phenyl-heptanoylamino)-pentanoic acid [KH064]) attenuated secretion of PGE(2) from human immune cells stimulated with the fatty acid, palmitic acid, or with lipopolysaccharide. Oral administration of KH064 (5 mg/kg/day) to rats fed the high-carbohydrate, high-fat diet prevented the overexpression of pla2g2a and the increased macrophage infiltration and elevated PGE(2) concentrations in adipose tissue. The treatment also attenuated visceral adiposity and reversed most characteristics of metabolic syndrome, producing marked improvements in insulin sensitivity, glucose intolerance, and cardiovascular abnormalities. We suggest that pla2g2a may have a causal relationship with chronic adiposity and metabolic syndrome and that its inhibition in vivo may be a valuable new approach to treat obesity, type 2 diabetes, and metabolic dysfunction in humans.

• Authors: Abishek Iyer, Junxian Lim, Hemant Poudyal, Robert C Reid, Jacky Y Suen, Julie Webster, Johannes B Prins, Jonathan P Whitehead, David P Fairlie, Lindsay Brown
• Journal: Diabetes (Diabetes) Vol. 61 Issue 9 Pg. 2320-9 (Sep 2012) ISSN: 1939-327X [Electronic] United States
• PMID: 22923652 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• 5-(4-benzyloxyphenyl)-4S-(7-phenylheptanoylamino)pentanoic acid
• Pentanoic Acids
• Tumor Suppressor Proteins
• Group II Phospholipases A2
• PLA2G2A protein, human
• Phospholipases A2, Calcium-Independent
• Plaat3 protein, rat
• Dinoprostone

Topics

• Adipocytes (drug effects, physiology)
• Adipose Tissue (physiology)
• Animals
• Cell Line
• Diet, High-Fat
• Dinoprostone (metabolism)
• Glucose Intolerance (prevention & control)
• Group II Phospholipases A2 (antagonists & inhibitors)
• Humans
• Insulin Resistance
• Lipolysis (drug effects)
• Macrophages (physiology)
• Male
• Mast Cells (physiology)
• Metabolic Syndrome (prevention & control)
• Mice
• Monocytes (physiology)
• Obesity (physiopathology)
• Pentanoic Acids (pharmacology)
• Phospholipases A2, Calcium-Independent (biosynthesis)
• Rats
• Rats, Wistar
• Signal Transduction (drug effects)
• T-Lymphocytes (physiology)
• Tumor Suppressor Proteins (biosynthesis)