AHR

Overview

AHR (aryl hydrocarbon receptor) is a ligand-activated transcription factor best known for sensing a wide range of endogenous Metabolites and environmental compounds. In biomedical research, it is commonly studied as a regulator of immune signaling, epithelial barrier function, xenobiotic response, and metabolic adaptation. Upon activation by agonists such as indole-derived microbial Metabolites or therapeutic small molecules, AHR can influence downstream pathways including NF-κB, MAPK, NLRP3-related inflammatory signaling, and lipid metabolism.

Recent studies have highlighted AHR as a mechanistic node linking the gut microbiota, mucosal integrity, inflammatory control, and tissue repair. In the contexts provided here, AHR was investigated in intestinal disease, skin inflammation, spinal cord injury, and cancer-related metabolic remodeling, often in combination with compounds such as tapinarof, indole-3-propionic acid, indole-3-carbinol, and irinotecan-associated nanomedicine strategies. These studies collectively support AHR as a biologically important target in inflammation-associated and metabolism-associated disease processes.

Focus of Latest Publications

Recent publications investigated AHR as a signaling target across several disease models, with a common theme of pathway modulation by endogenous or pharmacologic agonists.

In a study on food-grade TiO2 exposure and intestinal barrier injury, Lactobacillus and its metabolite indole-3-propionic acid (ILA), described as an AHR agonist, were significantly downregulated after oral ingestion of fg-TiO2. This reduction decreased AHR activation and was associated with loss of mucin sulfation in colon tissues. The work placed AHR downstream of a gut microbiota–metabolite axis and linked it to maintenance of the intestinal mucus barrier.

In a zebrafish model of TNBS-induced inflammatory bowel disease, Huoxiang-Huanglian treatment increased aryl hydrocarbon receptor (AhR) expression while reducing inflammatory and oxidative stress markers, including IL-1β, TNF-α, MDA, NLRP3, Caspase-1, NF-κB p65, and ODC1. This suggests that AHR upregulation may contribute to suppression of the NLRP3 inflammasome and improvement of inflammatory bowel disease phenotypes. The study also reported increases in IL-10 and superoxide dismutase, consistent with a shift toward anti-inflammatory and antioxidant responses.

In skin research, tapinarof was described as a novel AhR agonist recently approved for psoriasis. In an imiquimod-induced HaCaT-THP-1 co-culture model, tapinarof-loaded nanogels were evaluated for their anti-inflammatory effects, placing AHR activation in the context of keratinocyte–immune cell crosstalk and psoriasis-related inflammation. Although the provided context emphasizes formulation and model design, the study supports the use of AHR agonism as a therapeutic strategy in inflammatory skin disease.

In a spinal cord injury study using a mouse SCI model and astrocyte model, indole-3-propionic acid was reported to suppress NF-κB/MAPK signaling pathways by activating AHR. The authors concluded that AHR activation contributed to reduced astrocyte inflammation and improved motor function recovery after injury. This positions AHR as a mediator of neuroinflammatory control in central nervous system repair.

In colorectal cancer-related research, a self-assembled irinotecan nanomedicine was reported to abolish liver metastasis driven by irinotecan-induced steatohepatitis through activating the AHR/CPT1A axis and promoting fatty acid oxidation of hepatocytes. This finding connects AHR to hepatic metabolic reprogramming and suggests that AHR signaling can influence the tumor-promoting consequences of chemotherapy-associated liver injury. The study also referenced colorectal cancer and liver metastasis in the setting of irinotecan hydrochloride exposure.

Across these studies, AHR emerged as a biologically versatile receptor involved in microbiota-derived signaling, epithelial barrier maintenance, inflammatory suppression, and metabolic regulation. Related entities such as anti-inflammatory cytokines, C-C motif chemokine ligand 2, IFNG, IL17A, Prostaglandin-endoperoxide synthase 2, and superoxide dismutase were part of the broader inflammatory context in which AHR was studied, underscoring its role as a central modulator rather than a disease-specific marker.

Key Publications

Jun Food-grade TiO2 impairs intestinal mucus barrier via disrupting the gut microbiota-ILA-mucin sulfation axis: novel insights and dietary intervention strategies. (Journal of nanobiotechnology, 2026, PMID 42289709): "It was found that Lactobacillus and its metabolite ILA, an aryl hydrocarbon receptor (AHR) agonist, was significantly downregulated following oral ingestion of fg-TiO2, which decreased the activation of AHR and ultimately led to a loss in mucin sulfation in colon tissues."
Jun In Vitro Investigation of Tapinarof-Loaded Nanogels in an Imiquimod-induced HaCaT-THP-1 Co-Culture Model. (European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences, 2026, PMID 41864521): "Tapinarof is a novel aryl hydrocarbon receptor (AhR) agonist that has recently been approved for the treatment of psoriasis."
Jun Ameliorative Effect and Mechanism of Huoxiang-Huanglian on TNBS-Induced Inflammatory Bowel Disease in Zebrafish. (Biomedical chromatography : BMC, 2026, PMID 42124338): "HH treatment reduced interleukin-1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α), malondialdehyde (MDA), NLR family pyrin domain containing 3 (NLRP3), Caspase-1, nuclear factor kappa B (NF-κB) p65, and ODC1 levels, while increasing interleukin-10 (IL-10), superoxide dismutase (SOD), and aryl hydrocarbon receptor (AhR) expression."
May Indole-3-propionic acid inhibits astrocyte inflammation and promotes motor function recovery after spinal cord injury via the AhR/NF-κB/MAPK axis. (Neuropharmacology, 2026, PMID 41663028): "Transcriptomic and mechanistic investigations reveal that IPA suppressed NF-κB/MAPK signaling pathways by activating the aryl hydrocarbon receptor (AhR)."
May A Self-Assembled Irinotecan Nanomedicine Abrogates Steatohepatitis-Induced Liver Metastasis and Potentiates Antitumor Efficacy against Colorectal Cancer. (ACS nano, 2026, PMID 42007878): "NICER abolishes liver metastasis driven by irinotecan-induced steatohepatitis through activating the AHR/CPT1A axis and promoting fatty acid oxidation of hepatocytes."