a, Average relative abundance of prevalent microbiota at the class level in the FMT experiments, comparing age-matched controls and transplanted mice (n = 8, 4 males and 4 females, in all groups) and donor mice (n = 4, pooled samples from male and female mice). The low-abundance bacteria group includes all bacterial classes representing less than 0.1% of the total. Transplants began at ~6–8 weeks of age and metagenome profiling was analyzed after four rounds of FMT (2 weeks after microbiota depletion). Donor mice, both WT and LmnaG609G/G609G, were ~18–20 weeks old. p, phylum; c, class. b, UPGMA trees representing the beta-diversity analysis of control, transplanted and donor mice in each experimental condition, using Bray–Curtis dissimilarity (Supplementary Table 1). c, Comparison of spleen weight between control WT (n = 4), LmnaG609G/G609G (n = 4), LmnaG609G/G609G mice transplanted with WT microbiota (G609G-WTmic; n = 4) and LmnaG609G/G609G mice transplanted with microbiota from older LmnaG609G/G609G mice (G609G-oG609Gmic n = 4). Analyses were performed with one-way ANOVA with Sidak’s multiple comparison test. Exact adjusted P values are represented within the plot. d, mRNA relative levels (in log10 scale) of inflammatory interleukins in the ileum of WT (n = 9), G609G-control (n = 9), G609G-WTmic (n = 4) and G609G-oG609Gmic (n = 4) mice. Differences were analyzed with ANOVA with Sidak's multiple comparisons test relative to G609G-control mice. Exact adjusted P values are represented within the plot. For c and d, in the box plots, upper and lower hinges correspond to the first and third quartiles, the center line represents the median, whiskers indicate the highest and lowest values that are within 1.5 × IQR, and data beyond the end of the whiskers are outliers and plotted as points. e, Comparison of the number of mice dead and alive between LmnaG609G/G609G (Ctrl; n = 11) and LmnaG609G/G609G mice transplanted with WT microbiota (WTmic; n = 11) at the 80th percentile of the overall survival. Differences were analyzed by one-sized Fisher’s exact test (P = 0.04). f, Percentage survival of LmnaG609G/G609G (n = 11) and LmnaG609G/G609G mice transplanted with buffer (LmnaG609G-EmptyT; n = 8). Transplants started at ~8–10 weeks of age. Differences were analyzed with the log-rank Mantel–Cox test and BH correction was applied after pairwise comparisons between all experimental groups, including those described in Fig. 3f (P = 0.76). Hazard ratio (HR) was calculated using a Cox proportional model (HR of 1.7 [95% confidence interval (CI) 0.64–4.88], P = 0.27). Median and maximal survival are indicated in the Kaplan–Meier plot.