Failure of colonization following gut microbiota transfer exacerbates DSS-induced colitis

Abstract

To study the impact of differing specific pathogen-free gut microbiomes (GMs) on a murine model of inflammatory bowel disease, selected GMs were transferred using embryo transfer (ET), cross-fostering (CF), and co-housing (CH). Prior work showed that the GM transfer method and the microbial composition of donor and recipient GMs can influence microbial colonization and disease phenotypes in dextran sodium sulfate-induced colitis. When a low richness GM was transferred to a recipient with a high richness GM via CH, the donor GM failed to successfully colonize, and a more severe disease phenotype resulted when compared to ET or CF, where colonization was successful. By comparing CH and gastric gavage for fecal material transfer, we isolated the microbial component of this effect and determined that differences in disease severity and survival were associated with microbial factors rather than the transfer method itself. Mice receiving a low richness GM via CH and gastric gavage exhibited greater disease severity and higher expression of pro-inflammatory immune mediators compared to those receiving a high richness GM. This study provides valuable insights into the role of GM composition and colonization in disease modulation.

Keywords: DSS-induced colitis; Fecal microbiota transfer (FMT); Gut microbiota transfer; Inflammatory bowel disease (IBD); Microbiome colonization efficiency.

Figure 1.

Characterization and comparison of the six transfer groups to determine efficiency of GM transfer. Principal coordinate analysis comparing the three transfer methods of the (a) GM^High and the (b) GM^Low group’s beta diversity to their donors. X and Y axes labeled with percent of variation contributed by Principal coordinate 1 (PCo1) and PCo2, respectively. Two-way PERMANOVA for main effects of transfer method and recipient/donor (Sup Table S2), followed by a one-way PERMANOVA to test pairwise comparisons between donor and recipient (Sup Table S3). Comparison of donor and recipient GM at seven weeks of age for the (c) GM^High and (d) GM^Low cohorts. Bars represent mean chao-1 richness +/− SD. Two-way ANOVA for main effects of transfer method and sex. ns - not significant, **** p<0.0001.

Figure 2.

Comparison DSS-colitis disease phenotype differences of the six transfer groups. (a) Comparison of the DSS-induced weight loss between the GM^High cohort transfer methods. One-way ANOVA for effect of transfer method (p = 0.013, F = 4.5). Tukey post hoc for pairwise comparisons. (b) Comparison of the DSS-induced weight loss between the GM^Low cohort transfer methods. Kruskal-Wallis ANOVA on ranks for effect of transfer method (p <0.0001, F = 51.4). Dunn’s post hoc for pairwise comparisons. Each data point in panels (a) and (b) represents transfer method mean percent weight change +/− SEM. DSS-induced disease survivability of the (c) GM^High cohorts and the (d) GM^Low cohorts. Cox proportional hazards for main effects of transfer method and sex. (e) Colon lengths for each cohort following DSS administration and (f) DSS-induced lesion scores for each cohort. Groups that differ in letter designation are statistically significant from each other, while groups that share the same letter designation are not statistically significant from each other. Three Way ANOVA for main effects of transfer method, transfer direction, and sex. ns - not signification, **** p<0.0001.

Figure 3.

Comparison of co-housing and gavage GM transfer efficiency and DSS-induced DSS phenotype in each transfer direction. (a) PCoA comparing the GM beta diversity of the CH and GA cohorts in each transfer direction. X and Y axes labeled with percent of variation contributed by PCo1 and PCo2, respectively. Two-way PERMANOVA for main effects of transfer method and transfer direction. (b) Chao-1 richness of each co-housing and gavage cohorts. Three-way ANOVA for main effects of transfer method, transfer direction, and sex. (c) DSS-induced weight loss comparison of the co-housing and gavage cohorts. Each point represents group mean percent weight change +/− SEM. Two-way ANOVA for main effects of transfer method and transfer direction. (d) DSS-induced disease survivability of the co-housing and gavage cohorts. Cox proportional hazards for main effects of transfer method, transfer direction, and sex. (e) Colon lengths and (f) histological lesion scores caused by DSS-induced colitis. Three-way ANOVA for main effects of transfer method, transfer direction, and sex. **p<0.01, ***p<0.001, ****p<0.0001.

Figure 4.

Immune mediator concentrations from the co-housing and gavage cohorts’ colons following DSS-induced colitis. Volcano plots comparing the cytokine and chemokine concentrations between (a) GM^High and GM^Low cohorts, and (b) gavage and co-housing cohorts. Immune mediator concentration comparison of the co-housing and gavage cohorts for (c) macrophage inflammatory protein 2-alpha (MIP-2α), (d) interlukin 22 (IL-22), and (e) interlukin 6 (IL-6). Bars represent mean immune mediator concentrations +/− SD. Three-way ANOVA for main effects of transfer method, transfer direction, and sex. *p<0.05, **p<0.01, ***p<0.001.