Peisong Gao

Background: Allergic rhinitis (AR) is a common airway disease characterized by epithelial barrier dysfunction and Type 2 inflammation. Although the aryl hydrocarbon receptor (AhR) regulates mucosal immunity and epithelial homeostasis, its role in epithelial pathology in AR remains poorly defined. We sought to determine the contribution of AhR signaling to AR pathogenesis and to identify downstream mechanisms linking barrier dysfunction to Type 2 inflammation. Methods: AhR expression and transcriptomic profiles were analyzed in nasal tissues from AR patients and controls. AhR‐deficient ( AhR ^‐/‐ ) mice and CC10‐CreER ^TM ; p16 ^f/f ( p16 ^cKO ) mice were used to assess the contributions of AhR signaling and p16‐dependent epithelial senescence‐associated programs to allergic inflammation and barrier integrity. Mechanistic pathways were interrogated using transcriptomic analysis, and pharmacologic modulation was evaluated by molecular docking and functional assays. Results: AhR expression was significantly increased in nasal epithelial cells from AR patients. AhR ^‐/‐ AR mice exhibited reduced Type 2 inflammation and preservation of epithelial barrier integrity. Transcriptomic analysis revealed enrichment of senescence‐associated signatures in AR epithelium. AhR deficiency in primary epithelial cultures and AhR ^‐/‐ mice markedly attenuated epithelial senescence‐associated programs. Consistently, p16 ^cKO AR mice showed reduced allergic inflammation and improved barrier function. Mechanistically, NKX3‐1 was identified as an AhR‐interacting regulator in cell‐cycle arrest. Gain‐ and loss‐of‐function studies demonstrated that NKX3‐1 contributes to allergen‐induced epithelial senescence‐associated programs. Finally, curcumin attenuated epithelial senescence‐associated phenotypes with concomitant suppression of AhR and NKX3‐1 expression. Conclusion: These findings support a context‐dependent model in which AhR–NKX3‐1‐associated epithelial senescence programs contribute to barrier dysfunction and allergic inflammation in AR.

Background: Airway epithelial barrier dysfunction is a central feature of asthma pathogenesis, yet the molecular mechanisms by which post‐translational modifications regulate epithelial integrity remain incompletely understood. Fucosylation has emerged as a potential regulator of epithelial homeostasis across mucosal tissues. Objective: We sought to investigate whether epithelial fucosylation contributes to allergen‐induced barrier dysfunction and airway inflammation and to define their underlying mechanisms. Methods: Fucosylation levels were assessed in saliva from children with asthma using mass spectrometry. Air‐liquid interface epithelial cultures were used to assess barrier function by transepithelial electrical resistance, tight junction protein expression and cytokine release. Transcriptomic analyses were performed to identify dysregulated fucosylation pathways. Fut1 was selectively inhibited in vivo and in vitro using intratracheally delivered AAV6‐encoded shRNA. Downstream targets were also evaluated by RNA sequencing. Results: Fucosylation was significantly increased in saliva from children with asthma and in allergen‐exposed mouse airways. Pharmacologic inhibition of fucosylation preserved epithelial barrier integrity, maintained junctional organization and reduced allergen‐induced epithelial cytokine release. Transcriptomic profiling identified fucosylation as a major upregulated pathway, with increased expression of Fut1, Fut2, Fut7 and Fut9. Epithelial‐specific Fut1 knockdown attenuated Th2‐driven inflammation, preserved epithelial junctional architecture and suppressed alarmin release. Integrated analyses revealed 56 Fut1‐dependent genes enriched in cell‐adhesion pathways, including Cdh12 , App , Ank3 and Cd9 . Fut1‐CDH12 protein interaction was confirmed by immunoprecipitation, and FUT1‐dependent induction of CDH12 disrupted epithelial junctional organization and barrier function. Conclusion: These findings identify the FUT1‐CDH12 axis as a previously unrecognized epithelial mechanism promoting barrier dysfunction and allergic airway inflammation in asthma.

Allergic rhinitis (AR) is characterized by persistent epithelial remodeling, yet the upstream drivers and molecular mechanisms remain poorly defined. Analysis of nasal mucosa from AR patients revealed marked epithelial remodeling, oxidative stress, and Th2 inflammation. Transcriptome analysis of nasal mucosa revealed RhoA as one of the most upregulated genes, with expression positively correlating with disease severity. Using epithelial-specific RhoA-deficient mice (RhoA^cKO) and fasudil, a RhoA/ROCK inhibitor, we found that loss of RhoA/ROCK signaling markedly attenuated nasal Th2 inflammation, oxidative stress, and epithelial remodeling following allergen challenge. Further transcriptome analysis demonstrated that elevated RhoA activation was associated with increased epithelial cellular senescence. Both in vitro and in vivo studies confirmed that epithelial RhoA activation promotes allergen- or Th2 cytokine-induced cellular senescence, whereas genetic or pharmacologic elimination of senescent cells alleviated allergic inflammation and tissue remodeling. Pathway analysis identified PRKN (parkin) as a central node within RhoA-regulated, senescence-associated networks in AR. Functional studies showed that PRKN overexpression mitigated IL-13-induced mitochondrial dysfunction, oxidative stress, and epithelial senescence in human nasal epithelial cells. Together, these findings reveal that RhoA-driven epithelial senescence contributes to allergic inflammation and epithelial remodeling in AR and identify PRKN as a potential therapeutic target to restore epithelial homeostasis.

Environmental allergens trigger epithelial reactive oxygen species (ROS) production and cellular senescence, contributing to airway inflammation. The aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor responsive to environmental stimuli, may modulate this process. Single-cell transcriptomics from allergen-challenged bronchoalveolar brushings of allergic asthma and non-asthmatic allergic control subjects were analyzed for ROS, senescence, and AhR activity. Club cell-specific p16 knockout (p16^ΔScgb1a1) and AhR-deficient (AhR^ΔScgb1a1) mice were used to assess epithelial senescence and AhR function. Single-cell analysis revealed epithelial senescence as a hallmark of allergen-induced asthma. p16^ΔScgb1a1 mice exhibited reduced ROS levels and airway inflammation. Single-cell analysis also demonstrated increased AhR activity and ROS generation in airway epithelial cells of allergen-treated asthmatics, and ROS correlated positively with AhR activity and senescence. It was documented that the regulation of AhR on senescence was attenuated by VAF347, whereas AhR deficiency exacerbated ROS generation and inflammation in AhR^ΔScgb1a1 mice. RNA-seq identified senescence as a key AhR-regulated pathway, implicating c-Myc, TGF-β2, and SERPINE1 as major targets. AhR binding to the c-Myc promoter was confirmed by ChIP-PCR, and pharmacologic inhibition of c-Myc with EN4 reduced allergen-induced ROS, senescence, and inflammation. These findings demonstrate that epithelial AhR suppresses allergen-induced ROS generation and cellular senescence via direct regulation of c-Myc.