In the course of improving health and extending life - to a lesser degree in long-lived species, unfortunately - the practice of calorie restriction produces sweeping changes in near every aspect of metabolism. The deeper you look the more there is to find. Here is one of many examples:
Age-related alterations in the composition of skeletal muscle are linked to functional limitations, disability and metabolic disorders. Alterations in muscle damage and repair during aging can have deleterious consequences that lead to muscle degeneration and inflammation; most of the age-related declines in muscle homeostasis and function can be prevented by caloric restriction (CR) in laboratory animals. Changes in gene expression critically govern the age-related alterations in muscle mass and function.
MicroRNAs (miRNAs) regulate gene expression by recruiting the RNA‐induced silencing complex (RISC) to a target messenger RNA with which it shares partial complementarity, causing a reduction in the stability of the messenger RNA and/or its rate of translation. The relevance of miRNAs in disease development, muscle aging, and progression and prognosis of skeletal muscle diseases is not fully understood.
The profiling of miRNAs in aged tissues can provide direct links between aging, age-dependent regulation of miRNA abundance, and the involvement of miRNAs in normal aging and age-related diseases. In this study, changes in miRNAs in skeletal muscle from rhesus monkeys of different ages were assessed using RNA sequencing. Our results showed clear differences in muscle miRNA levels when comparing old and young animals, and that CR influences these age-induced changes in miRNA expression. Novel miRNAs were also identified in muscle of old and young rhesus monkeys, which could potentially be expressed in human skeletal muscle. Together, our study provides further support for the role of miRNAs in skeletal muscle aging and reveals the impact of CR on miRNA expression.