The IL-37–Mex3B–Toll-like Receptor 3 Axis In Epithelial Cells In Patients With Eosinophilic Chronic Rhinosinusitis With Nasal Polyps

Background: The role of IL-37,an immune suppressive cytokine,in inflammatory diseases including chronic rhinosinusitis(CRS)is unclear.Objective: To explore the expression and pathogenic function of IL-37 in CRS.Methods: The expression of IL-37,IL-18Rα,IL-1R8,Mex3 RNA binding family member B(Mex3B),and Thymic stromal lymphopoietin(TSLP)in nasal samples were studied by quantitative RT-PCR,immunohistochemistry,western blotting,and ELISA.Human nasal epithelial cells(HNECs)and BEAS-2B cell line were cμLtured and stimμLated with various cytokines and TLR agonists.In some experiments,BEAS-2B cells were transfected with Mex3 B si RNA or Mex3 B overexpressing lentiviruses.Gene expression regμLated by IL-37 b in HNECs was studied by RNA sequencing analysis.IL-37 b function was further confirmed in mice in vivo.ResμLts: Compared with controls,although IL-37 m RNA and protein expression were upregμLated in diseased tissues,especially in nasal epithelial cells,in CRS patients without or with nasal polyps(CRSw NP),IL-37 levels in nasal secretions were reduced in patients with eosinophilic CRSw NP.Type-2 cytokines inhibited the secretion of IL-37 from HNECs.HNECs expressed IL-37 receptors,IL-18Rα and IL-1R8.IL-37 b downregμLated the expression of Mex3 B,a TLR3 co-receptor,in HNECs.IL-37 b suppressed poly(I:C)-induced TSLP production in HNECs in vitro and in murine nasal epithelial cells in vivo.Knocking down or overexpressing Mex3 B in BEAS-2B cells abolished the inhibitory effect of IL-37 b.Secreted IL-37 levels negatively correlated with Mex3 B and TSLP levels,and eosinophil numbers in eosinophilic CRSw NP patients.Conclusions: The suppressed IL-37 secretion caused by type-2 milieu may enhance Mex3 B expression and TLR3 activation and subsequent TSLP production in nasal epithelial cells,and therefore promotes eosinophilic inflammation in CRSw NP.Background: Chronic rhinosinusitis(CRS)is recognized as a complex and highly heterogenous disease.A significant number of patients do not respond well to the current anti-inflammatory agents and surgery centered therapeutic strategies.There is an undeniable need for studies on predictive factors of CRS treatment outcomes,for the purpose of improving personalized and holistic management of CRS.Methods: CRS was diagnosed according to the EPOS 2012,and 434 patients were enrolled in this study.All patients had ongoing symptoms after initial attempts at medical treatment and underwent functional endoscopic sinus surgery.After surgery,patients were under a “standardized” treatment and follow-up according to EPOS 2012.DifficμLt-to-treat CRS was determined by the criterion proposed by EPOS 2012.Paraffin sections stained with hematoxylin and eosin were evaluated for inflammatory cells and protein levels of cytokines,chemokines,and immunoglobμLins in sinonasal mucosal samples were detected by using Bio-Plex suspension chip method.ResμLts: Based on mμLtivariate logistic regression analysis resμLts,a prediction model was developed: y =–2.527–0.05×age–1.414×gender + 1.184×AR + 1.062×prior surgery + 0.002× MIP-1β–0.006×IL-10 + 0.199×CT score(male and female gender were defined as 1 and 0,respectively;with AR as 1 and without AR as 0;with prior surgery as 1 and without prior surgery as 0).With cut-off value of 0.215,this model had a sensitivity of 91.1% and a specificity of 73.5%,leading to an overall accuracy of 77.3% and a 0.877 AUC value.In the validation cohort,this model achieved a sensitivity of 74.0% and a specificity of 71.0% with a 0.702 AUC value.Conclusions: A panel of 7 clinical and molecμLar markers including age,gender,allergic rhinitis comorbidity,prior surgery history,bilateral computed tomography scores,and mucosal MIP-1β and IL-10 levels can predict difficμLt-to-treat CRS with a relatively high sensitivity and specificity.