Systematic identification of exercise-induced anti-aging processes involving intron retention

Exercise is one of the most promising anti-aging interventions for maintaining skeletal muscle health in older adults. Nine "Aging Hallmarks," proposed by López-Otín, offer insights into the aging process; however, the link between these hallmarks and exercise is not fully elucidated. In this study, we conducted a systematic multi-omics analysis of skeletal muscles, focusing on aging and exercise, based on gene signatures for aging hallmarks. It is posited that mRNA splicing activity, linked to genomic instability, constitutes a fundamental hallmark of aging, and exhibits divergent expression patterns in response to aging and exercise. Additionally, we analyzed splicing events and discovered that intron retention (IR) is significantly impacted by aging, exhibiting contrasting changes to those induced by resistance training in the older cohort. The isoforms characterized by IR are notably enriched in mitochondrial functions. Conclusively, our results underscore the significance of splicing mechanisms as a novel aspect of aging hallmarks in skeletal muscles and propose a new mechanism by which exercise exerts its anti-aging effects on skeletal muscles through IR.