Periodic red light exposure eases cellular aging in mice

In an experiment in aged mice, researchers investigated the effects of periodic red light exposure. The light exposure significantly increased histone acetylation, a chemical modification of DNA packaging proteins, across the tissues and organs of the older mice. Following exposure, levels of SIRT4, a mitochondrial protein, were notably reduced in keratinocytes, the main cells in skin. At the same time, glycolysis, fatty acid metabolism, and the energy-producing tricarboxylic acid cycle were activated in these skin cells. The drop in mitochondrial SIRT4 promoted fatty acid oxidation and the energy cycle. This metabolic shift helped acetyl-CoA accumulate, raising histone acetylation and altering the expression of genes tied to cell senescence. Cellular aging was ultimately mitigated through coordinated shifts in metabolism, inflammation, and gene expression.