Metabolic Messengers: bile acids

Bile acids (BAs) are amphipathic steroid acids whose production and diversity depend on both host and microbial metabolism. These metabolites have emerged as biologically active signalling molecules that inform organs of nutrient availability. Their actions, through activation of the dedicated BA receptors FXR and TGR5, control the body's integrated physiological metabolic responses. Alterations in BA abundance or signalling are associated with metabolic diseases including obesity, type 2 diabetes, non-alcoholic steatohepatitis and atherosclerosis. Consequently, modulation of the BA pool could be a valid therapeutic approach, as demonstrated in preclinical and clinical models. Here we provide a historical summary of the discovery of BAs and their receptors, as well as a summary on the role of BA signalling in the control of energy homeostasis. Perino and Schoonjans summarize the most recent literature on the receptor-mediated role of bile acid signalling in the control of peripheral and central energy homeostasis.