Role of Arid5b in Thermogenesis and Adipose Tissue Browning

Background: Adipose tissue considerably influence metabolic homeostasis and play a central role in regulating whole-body energy and glucose metabolism. Previously, we have reported that mice with the global deletion of Arid5b are lean and have less fat in white and brown adipose tissues. However, this role is unknown in adipocyte specific Arid5b knockout (5bFKO) mice. Aim: We investigated the effects of adipose-specific deficiency of Arid5b on systemic glucose homeostasis and adipose tissue metabolism. Result: Deletion of Arid5b in adipose tissue using adiponectin promoter-driven Cre recombinase significantly improved glucose tolerance with significant reduction of insulin level. Body weight of 5bFKO mice was significantly reduced at the later age. Core body temperature of 5bFKO mice was significantly higher compared to the control mice. Robust increase in the protein expression of uncoupling protein 1 (Ucp1) was observed in inguinal white adipose tissue (iWAT) of 5bFKO mice housed at ambient temperature. This phenotype was further confirmed by prolonged cold exposure where Ucp1 and mitochondrial proteins such as pyruvate dehydrogenase (PDH), mitochondrially encoded cytochrome c oxidase (MTCO1) and ATP5A were substantially increased in iWAT of adipocyte specific Arid5b deficient mice. Gene expression of beige adipogenesis markers such as cell death inducing DFFA like effector A (Cidea) and iodothyronine deiodinase 2 (Dio2) were also significantly increased indicating browning of iWAT. Furthermore, loss of Arid5B in fat led to significant reduction in macrophages and total immune cells in iWAT. All together these results show that the deletion of Arid5b could promote browning of iWAT. Conclusion: These findings demonstrate that Arid5b regulates thermogenic genes expression to promote beige adipocytes formation and controls adipose inflammation. Inhibition of Arid5b may provide a novel therapeutic approach for obesity and diabetes. Disclosure M. Shukare: None. R. Huang: None. A. Ehsani: None. G. Zhang: None. J. Chalise: None. R. H. Whitson: None. K. Itakura: None.