CYP1A1 as a conserved metabolic circuit linking environmental sensing to immune regulation

Document Type

Review

Publication Date

1-1-2026

Abstract

Cytochrome P450 1A1 (CYP1A1) is traditionally described as a xenobiotic detoxification enzyme induced by the aryl hydrocarbon receptor (AhR). However, its tight inducible regulation, evolutionary conservation, and prominent expression in immune and barrier tissues where xenobiotic metabolism operates alongside environmental sensing and immune regulation suggest a broader regulatory role. This review proposes that CYP1A1 functions as a metabolic feedback regulator that controls the duration and intensity of AhR signaling. AhR rapidly senses diverse environmental, dietary, microbial, and endogenous ligands, while delayed induction of CYP1A1 limits signaling by metabolizing susceptible ligands and reducing their availability. Through this feedback architecture, ligand metabolism determines signal persistence and shapes downstream transcriptional and immune outcomes. Evidence from evolutionary analyses, signaling kinetics, tissue biology, and immunology indicates that CYP1A1-mediated metabolic feedback calibrates immune differentiation and barrier homeostasis across tissues. Disruption of this feedback, through persistent ligands or impaired CYP1A1 activity, uncouples environmental sensing from signal resolution and promotes sustained AhR activation. This framework reframes the AhR–CYP1A1 axis as a regulatory control circuit rather than a linear detoxification pathway and highlights signal duration and feedback integrity as key determinants of environmental immunotoxicity.

Publication Title

Archives of Toxicology

ISSN

03405761

DOI

10.1007/s00204-026-04384-1

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