Altered senescence and mitochondrial transcriptome defines age-related changes in satellite cells

Area of Science:

• Muscle stem cell biology
• Aging and regeneration
• Mitochondrial function

Background:

• Aging reduces skeletal muscle's regenerative capacity due to satellite cell decline.
• Aged satellite cells show impaired quiescence, proliferation, and differentiation.
• Mitochondrial function is crucial for stem cell metabolism and signaling during myogenesis.

Purpose of the Study:

• To investigate age-associated changes in mitochondrial function and senescence in satellite cells.
• To compare young and aged satellite cells across quiescent, proliferating, and differentiating states.
• To identify molecular targets for improving aged muscle stem cell function.

Main Methods:

• Comparative transcriptomic analysis of young and aged satellite cells.
• Utilized three publicly available microarray datasets.
• Examined gene expression profiles in quiescent, proliferating, and differentiating states.

Main Results:

• Aged satellite cells exhibit a metastable senescence state with dysregulated senescence pathways.
• Mitochondrial gene expression remodeling occurs upon activation, with aged cells showing stress, apoptotic, and metabolic pathway enrichment.
• Limited mitophagy activation in aged cells suggests impaired mitochondrial quality control.
• Senescence-associated secretory phenotype (SASP) components were increased in aged differentiating cells.

Conclusions:

• Age-associated disruptions in senescence and mitochondrial remodeling impact satellite cell function.
• Transcriptional changes in aged satellite cells contribute to impaired muscle regeneration.
• Identified potential targets for rejuvenating muscle stem cell function in aging individuals.