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ORIGINAL RESEARCH article

Front. Nutr.

Sec. Nutrition and Microbes

Volume 12 - 2025 | doi: 10.3389/fnut.2025.1597390

This article is part of the Research TopicXenobiotics, Gut Microbiota, and Chronic DiseaseView all 9 articles

Gut Microbiota and Protein-to-Protein Ratios in NAFLD: Insights from Mendelian Randomization and Murine Studies

Provisionally accepted
Langhuan  LeiLanghuan LeiWei  ShiWei ShiXing  YangXing YangJiali  LinJiali LinQiuyu  LiangQiuyu LiangXiaozhi  HuangXiaozhi HuangLiuxian  PanLiuxian PanWei  LiWei Li*
  • People's Hospital of Guangxi Zhuang Autonomous Region, Nanning, China

The final, formatted version of the article will be published soon.

Background: Gut microbiota and protein metabolism play critical roles in non-alcoholic fatty liver disease (NAFLD) progression, but their causal relationships remain unclear. This study integrates mendelian randomization (MR) analysis and experimental validation to identify microbial and molecular contributors to NAFLD and explore potential therapeutic targets.Methods: Two-sample MR analysis was performed to assess the causal effects of gut microbiota and protein-to-protein ratios on NAFLD using inverse variance-weighted, maximum likelihood, MR-Egger, weighted median, weighted mode, and Wald ratio methods. Sensitivity analyses were conducted to ensure result robustness. Mediation analysis was applied to examine whether protein-to-protein ratios mediate the link between gut microbiota and NAFLD.Results: MR analysis identified 19 gut microbial taxa and 148 protein-to-protein ratios significantly associated with NAFLD. Additionally, 49 significant mediation relationships were identified, where 7 gut microbial taxa influenced NAFLD via 45 protein-to-protein ratios. MR analysis identified 38 proteins significantly associated with NAFLD, derived from 192 unique proteins involved in 148 NAFLD-related protein-to-protein ratios. Experimental validation confirmed the protective role of Lactobacillus salivarius, which alleviated hepatic lipid accumulation, improved glucose-lipid metabolism, and reduced inflammatory cytokine expression. Among the identified targets, the hepatic mRNA expression levels of ANGPT1, SKAP2, SPARC, and STAMBP were significantly upregulated in NAFLD tissues and were markedly reduced following Lactobacillus salivarius supplementation.This study establishes a causal link between gut microbiota, protein metabolism, and NAFLD, identifying microbial and molecular targets for intervention.The findings support microbiota-based therapies and protein biomarkers for NAFLD management, warranting further clinical validation.

Keywords: Gut Microbiota, protein-to-protein ratios, NAFLD, Mendelian randomization, Lactobacillus salivarius

Received: 21 Mar 2025; Accepted: 30 Jun 2025.

Copyright: © 2025 Lei, Shi, Yang, Lin, Liang, Huang, Pan and Li. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Wei Li, People's Hospital of Guangxi Zhuang Autonomous Region, Nanning, China

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