Theobromine suppresses adipogenesis through enhancement of CCAAT-enhancer-binding protein β degradation by adenosine receptor A1. 
Theobromine, a methylxanthine derived from cacao beans, reportedly has various health-promoting properties but molecular mechanism by which effects of theobromine on adipocyte differentiation and adipogenesis remains unclear.  In this study, we aimed to clarify the molecular mechanisms of the anti-adipogenic effect of theobromine in vitro and in vivo.  ICR mice (4week-old) were administered with theobromine (0.1g/kg) for 7days.  Theobromine administration attenuated gains in body and epididymal adipose tissue weights in mice and suppressed expression of adipogenic-associated genes in mouse adipose tissue.  In 3T3-L1 preadipocytes, theobromine caused degradation of C/EBPβ protein by the ubiquitin-proteasome pathway.  Pull down assay showed that theobromine selectively interacts with adenosine receptor A1 (AR1), and AR1 knockdown inhibited theobromine-induced C/EBPβ degradation.  Theobromine increased sumoylation of C/EBPβ at Lys133.  Expression of the small ubiquitin-like modifier (SUMO)-specific protease 2 (SENP2) gene, coding for a desumoylation enzyme, was suppressed by theobromine.  In vivo knockdown studies showed that AR1 knockdown in mice attenuated the anti-adipogenic effects of theobromine in younger mice.  Theobromine suppresses adipocyte differentiation and induced C/EBPβ degradation by increasing its sumoylation.  Furthermore, the inhibition of AR1 signaling is important for theobromine-induced C/EBPβ degradation.