{"doi":"10.1101/2020.01.09.900555","title":"Altered polarization of PAR-2 signaling during airway epithelial remodeling","abstract":"ABSTRACT Background Protease-activated receptor 2 (PAR-2) is activated by proteases involved in allergy and triggers airway epithelial secretion and inflammation. PAR-2 is normally expressed basolaterally in differentiated nasal ciliated cells. Objective We tested if epithelial remodeling during diseases characterized by loss of cilia and squamous metaplasia may alter PAR-2 polarization. Methods Endogenous PAR-2 responses were measured by live cell calcium and cilia imaging, measurement of fluid secretion, and quantification of cytokines. We utilized airway squamous cell lines, primary differentiated air-liquid interface cultures, and tissue explants. Cells were exposed to disease-related modifiers that alter epithelial morphology, including IL-13, cigarette smoke condensate, and retinoic acid deficiency. We used concentrations and exposure times that altered epithelial morphology without causing breakdown of the epithelial barrier, likely reflecting early disease states. Results PAR-2 signaling in airway squamous cells activated calcium and inflammatory responses. Squamous cells cultured at air liquid interface (ALI) responded to PAR-2 agonists applied both apically and basolaterally. Primary well-differentiated nasal epithelial ALI cultures responded only to basolateral PAR-2 stimulation. Primary cultures exposed to IL-13, cigarette smoke condensate, or reduced retinoic acid responded to both apical and basolateral PAR-2 stimulation. Nasal polyp tissue, but not control middle turbinate, exhibited apical calcium responses to PAR-2 stimulation. However, isolated ciliated cells from both polyp and turbinate maintained basolateral PAR-2 polarization. Conclusions Squamous metaplasia and/or loss of cilia enhances apical PAR-2 responses. Altered PAR-2 polarization in dedifferentiated or remodeled epithelia may contribute to increased sensitivity to inhaled protease allergens in inflammatory airway diseases.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2020,"id":128747,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":0,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9596,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2020-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":579444,"name":"Jenna R. Freund","orcid":"0000-0001-8264-8318","position":1,"is_corresponding":false},{"id":580046,"name":"Benjamin M. Hariri","orcid":null,"position":2,"is_corresponding":false},{"id":406877,"name":"Nithin D. Adappa","orcid":"0000-0002-0339-8769","position":3,"is_corresponding":false},{"id":232128,"name":"Nithin D. Adappa","orcid":"0000-0002-7535-9339","position":4,"is_corresponding":false},{"id":579445,"name":"Robert J. Lee","orcid":"0000-0001-5826-6686","position":5,"is_corresponding":false},{"id":579443,"name":"Ryan M. Carey","orcid":"0000-0002-0186-2265","position":0,"is_corresponding":true}],"reference_count":65,"raw_metadata":null,"created_at":"2026-07-18T23:15:42.522809Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}