摘要
Among the four prostaglandin E2 receptors,EP3 receptor is the one most abundantly expressed in white adipose tissue(WAT).The mouse EP3 gene gives rise to three isoforms,namely EP3α,EP3β,and EP3γ,which differ only at their C-terminal tails.To date,functions of EP3 receptor and its isoforms in WAT remain incompletely characterized.In this study,we found that the expression of all EP3 isoforms were downregulated in WAT of both db/db and high-fat diet-induced obese mice.Genetic ablation of three EP3 receptor isoforms(EP3^(−/−)mice)or EP3αand EP3γisoforms with EP3βintact(EP3βmice)led to an obese phenotype with increased food intake,decreased motor activity,reduced insulin sensitivity,and elevated serum triglycerides.Since the differentiation of preadipocytes and mouse embryonic fibroblasts to adipocytes was markedly facilitated by either pharmacological blockade or genetic deletion/inhibition of EP3 receptor via the cAMP/PKA/PPARγpathway,increased adipogenesis may contribute to obesity in EP3^(−/−)and EP3βmice.Moreover,both EP3^(−/−)and EP3βmice had increased lipolysis in WAT mainly due to the activated cAMP/PKA/hormone-sensitive lipase pathway.Taken together,our findings suggest that EP3 receptor and itsαandγisoforms are involved in both adipogenesis and lipolysis and influence food intake,serum lipid levels,and insulin sensitivity.
基金
supported by the National Basic Research Program of China(973 Program)(2012CB517504 to Y.-F.G.)
the National Natural Science Foundation of China(81390351,81270275,81200511,and 81030003 to Y.-F.G.)
National Institutes of Health grants(DK46205 to R.M.B.)
the Swedish Research Council(to J.-A.G.),and Shenzhen Peacock Plan&JCYJ 20140418095735626.
