The Mechanism Of TFF3 In The Protection Of Epithelial Barrier In Chronic Rhinosinusitis With Nasal Polyps

Chronic rhinosinusitis(CRS)is a chronic mucosal inflammation that occurs in the nasal cavity and sinuses,affecting about 10% of the global population and bringing a huge burden to patients and society.The destruction of tight junction between mucosal epithelial cells and mucociliary clearance system is one of the important pathogenesis of CRS.Trefoil factor family(TFFs)exist in the mucus of digestive tract,respiratory tract,conjunctiva and inner ear,and are usually secreted together with mucin.A large number of studies have shown that TFFs play a role in mucosal protection and repair,and can promote mucosal growth and repair(cell migration).At the same time,it can regulate cell-cell junction,cell apoptosis and other processes.Previous studies have found that Staphylococcus aureus is one of the factors driving inflammation in CRSwNP,but the relationship between mucosal barrier and Staphylococcus aureus remains to be studied.Objective:1.To investigate the expression of TFF3,MUC5 AC,MUC5B and tight junctions in nasal epithelial cells of CRS patients,2.To investigate the expression of TFF3,MUC5 AC and Claudin-1 in S.aureus stimulated nasal mucosa,3.To investigate whether TFF3 knockdown could aggravate S.aureus induced abnormal expression of mucin MUC5 AC and Claudin-1.Methods:1.Nasal mucosal tissues from 10 CRSsNP patients,10 CRSwNP patients and 14 Control patients were selected.Immunofluorescence,RT-qPCR and Western blot were used to detect the expression of TFF3,MUC5 AC,MUC5B and tight junctions in nasal epithelial tissues of CRS patients.2.To determine the co-localization and interaction of TFF3 and MUC5 AC in the nasal mucosa epithelial tissues of the Control group,immunofluorescence staining was performed,and the corresponding proteins were extracted for co-immunoprecipitation.3.The expression levels of MUC5 AC,MUC5B and Claudin-1 in HNEPC were detected by RT-qPCR and immunofluorescence.4.The expression of MUC5 AC and Claudin-1 in KD-TFF3 HNEPC cells was detected by RT-qPCR and immunofluorescence.Results:1.The expression of TFF3 in nasal mucosa of CRSsNP patients was significantly higher than that of Control group,but it was lower in CRSwNP patients;The expression levels of MUC5 AC and MUC5 B were increased in CRSwNP patients.The expression of TJP1 and Claudin-1 in tight junction was decreased in CRSwNP.2.TFF3 and MUCAC were co-localized in the nasal epithelium and subepithelial cells.TFF3 can naturally bind to MUC5 AC and MUC5 B,suggesting their interaction.3.In HNEPC,the levels of Claudin-1 and TFF3 were significantly decreased and the expression of MUC5 AC was increased after S.aureus stimulation.4.In the TFF3-knockdown HNEPC cell line,the expression of Claudin-1 was further decreased after stimulation with S.aureus,but MUC5 AC expression was not significantly changed.Conclusions:1.The expression of TFF3 was increased in CRSsNP and decreased in CRSwNP.2.S.aureus could induce decreased expression of Claudin-1 and TFF3 and increased expression of MUC5 AC in nasal mucosa.3.Knockdown of TFF3 aggravated S.aureus induced abnormal expression of mucin MUC5 AC and Claudin-1.