Late-Life Short-Term Dietary Restriction Improves Intestinal Stem Cell Function and Alters Intestinal Stem Cell...

Intestinal regenerative capacity declines with age due to the declining intestinal stem cell (ISC) function. Dietary restriction (DR), the most robust anti-aging intervention to date, has been shown to improve ISC function in young mice.

The goal of this study is to evaluate the effect of short-term DR (stDR) on ISC function when implemented late in life.

Two- and twenty-one-month-old male C57BL/6 mice, fed on National Institutes of Health-31 (NIH-31), an open-source, unpurified, natural ingredient diet, were subjected to ad libitum feeding or stDR (40% DR for 4-mo) with 6 mice/age/treatment. Effects of age and stDR on ISC (leucine-rich repeat-containing G-protein coupled receptor 5) function was evaluated using in vitro enteroid-forming assay followed by ribonucleic acid sequencing (RNA-seq) analysis (using strand next-generation sequencing analysis software) and oxidative whole-genome bisulfite sequencing for deoxyribonucleic acid (DNA) methylation (using the R package methyl kit). Statistical analysis was conducted, where appropriate, using a 1-way analysis of variance with multiple testing corrections or Student's t-test.

Our data shows that stDR increases enteroid formation when implemented late in life by ≥10-fold (P ≤ 0.05). RNA-Seq analysis identified 38 genes not commonly linked to ISC function but showed a 2-fold change (P ≤ 0.05) with age, which was prevented by stDR. Finally, evaluation of the methylation status of selected genes from RNA-seq (Slc28a3, Ly9, Cd2, Platr4) showed changes in methylation at Cytosine-Guanine (CG) sites in the cis-acting regions of the genes with age which were also prevented by stDR (P ≤ 0.05).

Our study shows for the first time that late-life stDR can improve the function of leucine-rich repeat-containing G-protein coupled receptor 5 ISCs from old mice. These data suggest that late-life nutritional strategies might be effective in improving gut function that declines with age and reduce the risk of age-related intestinal disorders. Our study also provides the first data showing that DNA methylation may play a role in the ability of DR to improve ISC function.