The exercise-inducible bile acid receptor Tgr5 improves skeletal muscle function in mice.

TGR5 (also known as G protein-coupled bile acid receptor 1, GPBAR1) is a G protein-coupled bile acid receptor that is expressed in many diverse tissues. TGR5 is involved in various metabolic processes, including glucose metabolism and energy expenditure; however, TGR5's function in skeletal muscle is not fully understood. Using both gain- and loss-of-function mouse models, we demonstrate here that Tgr5 activation promotes muscle cell differentiation and muscle hypertrophy.

Identification of key amino acid residues in the hTGR5-nomilin interaction and construction of its binding model.

TGR5, a member of the G protein-coupled receptor (GPCR) family, is activated by bile acids. Because TGR5 promotes energy expenditure and improves glucose homeostasis, it is recognized as a key target in treating metabolic diseases. We previously showed that nomilin, a citrus limonoid, activates TGR5 and confers anti-obesity and anti-hyperglycemic effects in mice.

Dietary obacunone supplementation stimulates muscle hypertrophy, and suppresses hyperglycemia and obesity through the TGR5 and PPARγ pathway.

Obacunone is a limonoid that is predominantly found in Citrus. Although various biological activities of limonoids have been reported, little is known about the beneficial effects of obacunone on metabolic disorders. In the present study, we examined the effects of dietary obacunone supplementation on obese KKAy mice, to clarify the function of obacunone in metabolic regulation.