Fig. 1

Schematic representation of microbial rejuvenation experiment. Eight-week-old male C57BL6/J wildtype mice (n = 40) were aged until 120 weeks of age and every 8 weeks mice (n = 20 per group) received a microbial transfer from unrelated wildtype mice being either of the same age as the recipients (isochronic microbiome transfer—iMB) or being 8-week-old (young microbiome transfer—yMB) with the goal to rejuvenate the aging recipient mice with a young microbiome. Mice were monitored throughout the experiment and extensively phenotyped at final analysis by functional and behavioral tests (rotarod, grip strength, intestinal barrier function, glucose homeostasis). Furthermore, colonic and small intestinal tissue were subjected to bulk and single-cell transcriptome sequencing, and fecal samples collected throughout the experiment were subjected to 16S rRNA amplicon sequencing and metagenomics