The PGE2 EP3 Receptor Regulates Diet-Induced Adiposity in Male Mice.

Ceddia RP, Lee D, Maulis MF, Carboneau BA, Threadgill DW, Poffenberger G, Milne G, Boyd KL, Powers AC, McGuinness OP, Gannon M, Breyer RM
Endocrinology. 2016 157 (1): 220-32

PMID: 26485614 · PMCID: PMC4701878 · DOI:10.1210/en.2015-1693

Mice carrying a targeted disruption of the prostaglandin E2 (PGE2) E-prostanoid receptor 3 (EP3) gene, Ptger3, were fed a high-fat diet (HFD), or a micronutrient matched control diet, to investigate the effects of disrupted PGE2-EP3 signaling on diabetes in a setting of diet-induced obesity. Although no differences in body weight were seen in mice fed the control diet, when fed a HFD, EP3(-/-) mice gained more weight relative to EP3(+/+) mice. Overall, EP3(-/-) mice had increased epididymal fat mass and adipocyte size; paradoxically, a relative decrease in both epididymal fat pad mass and adipocyte size was observed in the heaviest EP3(-/-) mice. The EP3(-/-) mice had increased macrophage infiltration, TNF-α, monocyte chemoattractant protein-1, IL-6 expression, and necrosis in their epididymal fat pads as compared with EP3(+/+) animals. Adipocytes isolated from EP3(+/+) or EP3(-/-) mice were assayed for the effect of PGE2-evoked inhibition of lipolysis. Adipocytes isolated from EP3(-/-) mice lacked PGE2-evoked inhibition of isoproterenol stimulated lipolysis compared with EP3(+/+). EP3(-/-) mice fed HFD had exaggerated ectopic lipid accumulation in skeletal muscle and liver, with evidence of hepatic steatosis. Both blood glucose and plasma insulin levels were similar between genotypes on a control diet, but when fed HFD, EP3(-/-) mice became hyperglycemic and hyperinsulinemic when compared with EP3(+/+) fed HFD, demonstrating a more severe insulin resistance phenotype in EP3(-/-). These results demonstrate that when fed a HFD, EP3(-/-) mice have abnormal lipid distribution, developing excessive ectopic lipid accumulation and associated insulin resistance.

MeSH Terms (21)

Adipose Tissue, White Adiposity Animals Cell Size Crosses, Genetic Diabetes Mellitus, Type 2 Diet, High-Fat Insulin Resistance Lipid Metabolism Liver Macrophage Activation Male Mice, Inbred C57BL Mice, Knockout Muscle, Skeletal Necrosis Non-alcoholic Fatty Liver Disease Obesity Panniculitis Receptors, Prostaglandin E, EP3 Subtype Weight Gain

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