The prevalence of obesity has increased steadily over the last few decades and is a major risk factor for type 2 diabetes and cardiovascular disease. Obesity is associated with alterations in adipose tissue functioning leading to metabolic dysfunction. In previous studies, we have reported the role of lipocalin-type prostaglandin D2 synthase (L-PGDS) in glucose intolerance and atherosclerosis. More recently, we demonstrated that L-PGDS KO mice develop NAFLD even on a low fat diet. Our present study explored the role of L-PGDS in adipose tissue. We found decreased expression of L-PGDS in insulin resistant 3T3-L1 adipocytes. Enzymatic inhibition of L-PGDS in 3T3-L1 adipocytes using AT56 impaired insulin signaling by reducing the phosphorylation of AKT protein and the expression and translocation of GLUT4 to plasma membrane. Furthermore, we found that inhibition of L-PGDS reduces the expression of adiponectin and AMPK phosphorylation in 3T3-L1 adipocytes. Rosiglitazone treatment in insulin resistant 3T3-L1 adipocytes significantly increased L-PGDS expression. Treatment with rosiglitazone restored the expression of adiponectin and phosphorylation of AMPK in AT56 treated 3T3-L1 adipocytes. Correspondingly, we found decreased L-PGDS expression in visceral fat of obese humans. Cumulatively, these data confirm that the absence of L-PGDS results in decreased insulin sensitivity via impaired insulin signaling and reduced adiponectin levels in 3T3-L1 adipocytes. Thus, our findings suggest that L-PGDS plays a significant role in maintaining the insulin sensitivity in 3T3-L1 adipocytes and provides a novel opportunity for therapeutic intervention of obesity-associated metabolic syndrome.
A. Srivastava: None. T. Palaia: None. J. Lee: None. C. Hall: None. M. Stevenson: None. A.G. Fernando: None. L. Ragolia: None.
American Heart Association (15GRNT22420001); George Link, Jr. Foundation, Inc.