HMGB1/RAGE Signal Regulates Th17/IL-17 And Its Role In Bronchial Epithelial-mesenchymal Transformation

Objective:Bronchial asthma(referred to asthma for short)is a common heterogeneous chronic airway inflammatory disease,and its pathogenesis is still unclear.With the current increase in the number of bronchial asthma patients worldwide,researchers have studied the pathogenesis of asthma more and more.As we all know,the current research direction of the pathogenesis of asthma is mainly related to airway immune inflammation response,airway hyperresponsiveness and airway remodeling.Airway remodeling increases the severity of asthma.These structural changes include loss of epithelial integrity due to cell shedding,goblet cell proliferation,ciliated cell destruction,and airway epithelial-mesenchymal transition(EMT).It is known that airway remodeling is one of the reasons why severe asthma shows steroid resistance,in which EMT plays an important role.High Mobility Group Box 1(HMGB1)is a non-histone chromosome-binding protein which existes widely and conserves highly,and it is also a pro-inflammatory mediator.Receptor for advanced glycation end products(RAGE)is a multi-ligand pattern recognition receptor,which involved in multiple chronic inflammatory states.RAGE is also an important role receptor for HMGB1,and it mediates HMGB1 participation in various immune inflammatory responses.At present,the HMGB1/RAGE signaling pathway has been confirmed to be involved in the pathogenesis of many chronic airway diseases,which is closely related to the pathogenesis of airway inflammation in asthma patients,but the role of asthma airway EMT has not been reported.A large number of studies have found that Th17 cells can aggravate the process of airway inflammation,airway hyperresponsiveness and airway remodeling in asthmatic patients.IL-17 is a characteristic effector cytokine of Th17 cells,and it is important for studying the prevention and treatment of this type of asthma to understand the role of Th17/IL-17 signaling in airway remodeling and hormone-resistant asthma.Studies have pointed out that HMGB1 may be involved in regulating the polarization of Th2 and Th17,and HMGB1 is closely related to the differentiation regulation and secretion function of Th17 cells.However,whether Th17/IL-17 signaling is involved in the regulation of HMGB1/RAGE signaling and the relationship between airway EMT have not been reported.Therefore,this experiment is the first study to investigate the regulation of Th17/IL-17 signal by HMGB1/RAGE signal and its role in bronchial epithelial-mesenchymal transition.Methods:Obtaining wild-type C57 mouse-derived CD4~+T lymphocytes and CD4~+T cells that were transfected to silence RAGE,and then we performed group experiments to observe the HMGB1/RAGE signal regulate differentiation and functional expression of Th17/IL-17 in vitro.Then a normal EMT cell model was established using wild-type mouse-derived bronchial epithelial cells,and an EMT cell model was silenced RAGE(sh-RAGE)after transfection,and intervention groups were performed to observe the relationship between HMGB1/RAGE signal and bronchial EMT.Two kinds of cells were further cultured for 72h in co-culture with Th17 cells and 72 hours with IL-17 cytokine stimulation.The effects of Th17/IL-17 signaling on bronchial EMT were observed in vitro.Results:In vitro experiments,we found that HMGB1/RAGE signal can promote the differentiation and maturation of Th17 cells and promote the secretion of IL-17 cells in a concentration-dependent manner(p<0.05).In intervention experiments of EMT model of mouse bronchial epithelial cell,HMGB1/RAGE signal can promote the occurrence and development of bronchial EMT;and co-culture with Th17 or the addition of IL-17 factor can synergistically enhance the regulation of HMGB1/RAGE signal to promote the process of bronchial EMT(p<0.05).When RAGE is silenced,it will affect the signal transduction of HMGB1 and weaken the regulation of bronchial EMT(p<0.05).Conclusions:In vitro,HMGB1/RAGE signaling can synergistically enhance the process of bronchial epithelial-mesenchymal transition by promoting the differentiation of Th17 cells and increasing the secretion of IL-17.Combined with the results of our previous animal experiments,it is speculated that this may be one of the mechanisms of HMGB1 signaling involved in airway remodeling of asthma.