Dissecting the novel anti-obesity mechanism of prostaglandin D2via DP1 receptor agonism utilizing mouse 3T3-L1 adipocytes as well as primary human subcutaneous adipocytes

Abstract ID 97479 Poster Board 485 Obesity poses a serious health threat globally with concomitant rise in dreaded health consequences such as diabetes, dyslipidemia, and cardiovascular complications. It becomes even more clinically challenging when there is no FDA-approved therapeutic agent available to treat obesity safely. The prevalence of obesity in United States has increased from 30.5% in 2000 to 41.9% in 2020, illustrating a growing population that could benefit from a potent/efficacious anti-obesity therapeutic. Our in-vivo study identified severe fatty liver disease in Lipocalin Prostaglandin D2 Synthase (L-PGDS) knockout mice kept on high fat diet. Briefly, L-PGDS functions as a prostaglandin synthase where it catalyzes the isomerization of PGH2 to PGD2. PGD2 regulates its physiological function via two individual G-protein coupled receptors named DP1 and DP2. Interestingly, while studying lipid metabolism utilizing DP1 and DP2 receptor modulators in apoE−/− mice, DP1 receptor agonist (BW245C) group prevented significant weight gain despite keeping on high fat diet for 10 weeks. Moreover, DP1 receptor agonist group showed significantly increased total plasma bile acids compared to the control. This exciting finding prompted us to delve into investigating the anti-obesity mechanism of BW245C. DP1 receptor activation also induces intracellular cAMP levels in adipose tissue similar to bile acid receptor, TGR5 activation. This pathway stimulates energy expenditure in adipose tissue which eventually translates into weight loss. Therefore, to untangle this puzzle, we aimed to investigate the novel anti-obesity mechanism of DP1 receptor agonist, BW245C in mouse 3T3-L1 adipocytes as well as primary human subcutaneous adipocytes. The 3T3-L1 and primary human subcutaneous adipocytes are well-established models to study the process of adipogenesis, lipogenesis, lipolysis, oxidation of fatty acids and browning similar to the one observed in in-vivo setting. 3T3-L1 pre-adipocytes to adipocytes differentiation feasibility is established in our lab. Briefly, based on our preliminary results, differentiated 3T3-L1 adipocytes will be treated with sodium palmitate (250mM) to induce lipogenesis and with or without BW245C (0.001, 0.1, 1, 10, and 100 μM concentrations) for 24, 48 and 72 hrs. Change in adipocytes lipid accumulation will be measured as an experimental outcome which will be determined involving Oil Red O staining, cell lysate and supernatant triglyceride measurement and cyclic AMP release assay techniques. Further, sodium palmitate treated cell lysates will be subjected to measure adipogenesis and lipolysis related protein and mRNA expressions including uncoupling protein 1 (UCP1), CCAAT/enhancer-binding proteins α (C/EBP α); peroxisome proliferator-activated receptor γ (PPARγ); fatty acid-binding protein 4 (FABP4); acetyl-CoA carboxylase (ACC); fatty acid synthase (FAS); hormone-sensitive lipase (HSL) and adipose triglyceride lipase (ATGL). Obtained results will be recapitulated in primary human subcutaneous adipocytes. Once, we fully understand the role of DP1 receptor agonist in adipocytes, further detailed study will be carried out using ob/ob mice model on high fat diet in future. Collectively, dissecting a novel role of DP1 receptor agonist will possibly bring a potential future treatment of obesity. This research is supported by Seed Grant internal research funding award from the St. John's University, New York.