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 it exhibits divergent expression patterns in response to aging and exercise. Additionally, we analysed 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 characterised 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 intron retention. Key points summary Skeletal muscle aging involves significant structural and functional changes, including loss of muscle mass, decline in strength, and mitochondrial dysfunction, all influenced by genomic instability. Exercise has been identified as a key intervention that counters genomic instability and modulates mRNA splicing patterns, particularly through the regulation of Intron Retention, to mitigate aging effects in skeletal muscle. We reveal the novel role of IR, especially in principal isoforms, where it is linked to critical cellular processes like mitochondrial function, suggesting a targeted pathway through which exercise exerts its anti-aging effects. The findings provide new insights into the molecular mechanisms underlying the beneficial effects of exercise on aging skeletal muscle. This study lays the groundwork for future research on exercise-induced modulation of mRNA splicing as a therapeutic strategy for aging and potentially age-related diseases, pointing towards a significant shift in how we approach aging intervention strategies.