REVIEW article
Front. Cell. Infect. Microbiol.
Sec. Adaptive & Innate Immunity in Infection
Tryptophan Metabolism at the Crossroads of the Neuro-Immuno-Microbial Axis: Implications for Precision Medicine in Chronic Diseases
Provisionally accepted
- Fujian Normal University, Fuzhou, China
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Tryptophan metabolism connects the nervous, immune, and microbial systems and influences the onset and progression of chronic diseases such as cancer, neurodegeneration, and autoimmunity. This review summarizes the three major metabolic routes: the kynurenine pathway, the serotonin pathway, and microbial indole production. It outlines how their metabolites shape neural activity, immune regulation, and host–microbiota interactions. We further discuss the relevance of these metabolites as biomarkers and their potential therapeutic implications. By integrating recent insights into tryptophan-associated signaling networks, this review provides a concise framework for understanding their roles in chronic disease and guiding future precision medicine strategies.
Keywords: Gut-microbiota-brain axis, kynurenine pathway, Neuro-immuno-microbial axis, precision medicine, tryptophan metabolism
Received: 18 Sep 2025; Accepted: 05 Dec 2025.
Copyright: © 2025 XIA, You, Xia and Huang. 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: Jian-Zhong Huang
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