Andy
Retired committee member
Abstract
The circadian-regulated transcriptional repressor REV-ERB-α is a key mediator of skeletal muscle oxidative capacity, enhancing exercise performance when activated. Conversely its global genetic ablation leads to impaired performance. Simultaneously the kynurenine (KYN) pathway, involved in tryptophan degradation, produces neurotoxic metabolites under stress and inflammation, contributing to CNS dysfunction and fatigue. These mechanisms may underlie the fatigue and performance impairments caused by exhaustive exercise (EE).
This study investigated the interplay between REV-ERB-α and the KYN pathway in acute and chronic EE models. Time course analyses revealed that EE downregulated REV-ERB-α in skeletal muscle, correlated with KYN pathway alterations. Notably KYN metabolism shifted towards a neurotoxic profile, characterized by reduced KYN aminotransferase 1 (KAT1) and increased KYN 3-monooxygenase (KMO) expression in skeletal muscle, with increased KYN levels in the hippocampus. In vitro experiments using C2C12 myoblasts showed that REV-ERB-α knockout upregulated KAT1 and KMO, whereas overexpression selectively reduced KMO. Pharmacological activation of REV-ERB-α with SR9009 upregulated KAT1 in skeletal muscle and reduced KMO in the hippocampus of mice.
These findings reveal a dynamic relationship between REV-ERB-α and the KYN pathway, linking peripheral and central responses to EE. This study highlights REV-ERB-α and the KYN pathway as critical regulators of exercise-induced fatigue and suggests potential therapeutic targets to mitigate its effects, offering novel insights into the molecular basis of performance impairments associated with EE.
Open access