The exercise-mediated metabokine Beta-aminoisobutyric acid is an exercise mimetic driving skeletal muscle metabolic and functional adaptation

Skeletal muscle integrates many of the systemic signals, which contribute to the adaptive remodeling, and beneficial effects of exercise. One mechanism through which muscle mediates the systemic effects of exercise is through muscle-derived hormones known as myokines. We identified the metabolite β-aminoisobutyric acid (BAIBA) as an exercise-mediated small molecule myokine. BAIBA is secreted from muscle in response to increased expression of the transcriptional co-regulator PGC-1α, a master regulator of the muscle adaptive response to exercise. However, how BAIBA functions to regulate the adaptive responses of skeletal muscle to exercise remains poorly understood. We show that BAIBA improves muscle metabolism, exercise efficiency and performance in mice. Oxygen consumption (VO2) and energy expenditure are increased in BAIBA-treated mice. Furthermore, BAIBA increased soleus in situ muscle contractile force, fatigue resistance, mitochondrial number and function. We found that BAIBA drives muscle fiber-type switching to an oxidative phenotype in vivo. BAIBA regulates specific fiber-type gene expression in human myocytes through PPARΔ. Our findings demonstrate that BAIBA is a key paracrine myokine, which, in part, regulates the effects of exercise to improve muscle function with resultant effects on exercise performance. H.N.D. acknowledges the support of the Biotechnology and Biological Sciences Research Council (BB/T004231/1). This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.