Role of N-acetylkynurenine in mediating the effect of gut microbiota on urinary tract infection: a Mendelian randomization study

Yining He; Chao Han; Chengjuan Li; Xiaofan Yin; Jiawen Wang; Lina Gu; Ruxue Yan; Buhui Liu; Xuan Zhou; Weiming He

doi:10.3389/fmicb.2024.1384095

Role of N-acetylkynurenine in mediating the effect of gut microbiota on urinary tract infection: a Mendelian randomization study

Front Microbiol. 2024 Apr 22:15:1384095. doi: 10.3389/fmicb.2024.1384095. eCollection 2024.

Authors

Yining He^{1

2}, Chao Han^{1

3}, Chengjuan Li^{1

2}, Xiaofan Yin^{1

2}, Jiawen Wang^{1

2}, Lina Gu^{1

2}, Ruxue Yan^{1

2}, Buhui Liu⁴, Xuan Zhou⁵, Weiming He²

Affiliations

¹ The First School of Clinical Medicine, Nanjing University of Chinese Medicine, Nanjing, China.
² Division of Nephrology, Affiliated Hospital of Nanjing University of Chinese Medicine, Jiangsu Province Hospital of Chinese Medicine, Nanjing, China.
³ Yancheng Dafeng Hospital of Chinese Medicine, Teaching Hospital of Nanjing University of Chinese Medicine, Yancheng, China.
⁴ Department of Human Anatomy, Xuzhou Medical University, Xuzhou, China.
⁵ Department of Respiratory, The Fourth Affiliated Hospital of Nanjing Medical University, Nanjing, China.

Abstract

Introduction: This study explored the causal connections between gut microbiota (GM), urinary tract infection (UTI), and potential metabolite mediators using Mendelian randomization (MR).

Methods: We utilized summary statistics from the most comprehensive and extensive genome-wide association studies (GWAS) available to date, including 196 bacterial traits for GM, 1,091 blood metabolites, 309 metabolite ratios, alongside UTI data from ukb-b-8814 and ebi-a-GCST90013890. Bidirectional MR analyses were conducted to investigate the causal links between GM and UTI. Subsequently, two MR analyses were performed to identify the potential mediating metabolites, followed by a two-step MR analysis to quantify the mediation proportion.

Results: Our findings revealed that out of the total 15 bacterial traits, significant associations with UTI risk were observed across both datasets. Particularly, taxon g_Ruminococcaceae UCG010 displayed a causal link with a diminished UTI risk in both datasets (ukb-b-8814: odds ratio [OR] = 0.9964, 95% confidence interval [CI] = 0.9930-0.9997, P = 0.036; GCST90013890: OR = 0.8252, 95% CI = 0.7217-0.9436, P = 0.005). However, no substantial changes in g_Ruminococcaceae UCG010 due to UTI were noted (ukb-b-8814: β = 0.51, P = 0.87; ebi-a-GCST90013890: β = -0.02, P = 0.77). Additionally, variations in 56 specific metabolites were induced by g_Ruminococcaceae UCG010, with N-acetylkynurenine (NAK) exhibiting a causal correlation with UTI. A negative association was found between g_Ruminococcaceae UCG010 and NAK (OR: 0.8128, 95% CI: 0.6647-0.9941, P = 0.044), while NAK was positively associated with UTI risk (OR: 1.0009; 95% CI: 1.0002-1.0016; P = 0.0173). Mediation analysis revealed that the association between g_Ruminococcaceae UCG010 and UTI was mediated by NAK with a mediation proportion of 5.07%.

Discussion: This MR study provides compelling evidence supporting the existence of causal relationships between specific GM taxa and UTI, along with potential mediating metabolites.

Keywords: Mendelian randomization analysis; N-acetylkynurenine; blood metabolites; gut microbiota; urinary tract infection.

Grants and funding

The authors declare that financial support was received for the research, authorship, and/or publication of this article. This work was sponsored by the Jiangsu Provincial Medical Innovation Center (No. 202215), Research Project of Jiangsu Provincial Maternal and Child Health Care Association (FYX202308) awarded to WH, the Postgraduate Research and Practice Innovation Program of Jiangsu Province (grant number SJCX23_0907), awarded to YH, the Postgraduate Research and Practice Innovation Program of Jiangsu Province, awarded to JW (grant number SJCX23_0868).