Early-life exercise induces immunometabolic epigenetic modification enhancing anti-inflammatory immunity in middle-aged male mice

Exercise is usually regarded to have short-term beneficial effects on immune health. Here we show that early-life regular exercise exerts long-term beneficial effects on inflammatory immunity. Swimming training for 3 months in male mice starting from 1-month-old curbed cytokine response and mitigated sepsis when exposed to lipopolysaccharide (LPS) challenge, even after 11-month interval of detraining. Metabolomics analysis of serum and liver identified pipecolic acid (a non-encoded amino acid) as a pivotal metabolite responding to early-life regular exercise. We then explored histone epigenetic modifications and observed a significant increase of H3K4me3 expression in the liver of 15-month-old mice exposed to early-life exercise. To further unravel the prolonged increased pipecplic acid production raised by early-life exercise, we conducted ChIP-seq analysis and found H3K4me3 occupancy at Crym (a key enzyme responsible for catalyzing pipecolic acid production) promoter has a significant increase in hepatocytes of early-life exercised mice. Our findings demonstrate that early-life regular exercise enhances anti-inflammatory immunity during middle-aged phase in male mice via epigenetic immunometabolic modulation, in which hepatic pipecolic acid production plays a pivotal role. Chromatin immunoprecipitation DNA-sequencing (ChIP-seq) for H3K4me3 in primary hepatocytes isolated from 15-month-old early-life exercised or sedentary mice