Multi-omics reveal the key role of gut microbiota metabolism in adenine-induced chronic kidney disease.

The gut microbiota plays a crucial role in the progression of chronic kidney disease (CKD). The adenine-induced CKD mouse model is widely employed in preclinical research, yet the effects of adenine on the composition and metabolic function of the gut microbiota remain to be elucidated. This study aimed to test the hypothesis that adenine-induced alterations in the structure and function of the gut microbiota are significantly associated with the onset and progression of CKD. To this end, a mouse CKD model was established by alternating feeding with 0.15% and 0.20% adenine for 7 weeks. Multi-omics analysis (untargeted metabolomics, metagenomics, and spatial metabolomics) was performed to compare the adenine-induced CKD group with a standard diet-fed normal control group. Integrated analysis of plasma metabolomics and intestinal content metabolomics identified 94 differentially co-regulated metabolites: among these, indolelactic acid was significantly upregulated, while indole-3-propionic acid was significantly downregulated. The bile acid metabolic pathway also underwent marked perturbations: taurochenodeoxycholic acid and tauro-β-muricholic acid (two taurine-conjugated bile acids) were significantly elevated, whereas nordeoxycholic acid and norcholic acid were notably reduced. Integrated metabolomics-metagenomics analysis further demonstrated that Lactobacillus exhibited a significant positive correlation with a subset of upregulated metabolites (including indolelactic acid), while Taurinivorans muris showed a strong negative correlation with the taurine-conjugated bile acids. Additionally, renal spatial metabolomics revealed that phospholipid metabolic disorders in the adenine-induced CKD group directly contributed to the aggravation of renal inflammatory responses. Collectively, these findings reveal a gut microbiota-metabolite-kidney axis perturbed by adenine, providing novel insights into the pathogenesis of CKD and potential targets for metabolic intervention.