A 2-Hydroxybutyrate-mediated feedback loop regulates muscular fatigue
The metabolite 2-hydroxybutyrate (2HB) is produced by skeletal muscle acutely during exercise and persists for several hours in the blood post-exertion. We show here that 2HB directly inhibits branched- chain aminotransferase enzymes, and that this inhibition in turn triggers a SIRT4-dependent shift in the compartmental abundance of protein ADP-ribosylation. The 2HB-induced decrease in nuclear protein ADP-ribosylation leads to a C/EBP{beta} mediated transcriptional response in the branched-chain amino acid degradation pathway. This response to 2HB exposure leads to an improved oxidative capacity both in vitro and in vivo, with the latter mimicking the effects of exercise training on whole body metabolism. Thus, we show here that 2-HB production by skeletal muscle represents a novel mechanism for the modification of metabolism by exercise.