JNK Regulates RAGE Receptor Expression Of Bronchial Airway Epithelial Cells In Asthma

BackgroundAsthma is a heterogeneous disease characterized by chronic airway inflammation which is the essential and core link of the disease,resulting in airway remodeling.The non-allergic asthma phenotype which has no clear allergens,characterized by mixed inflammatory cells in the airway,and is not sensitive to hormones,gradually becomes a clinical treatment confusion.So it is meaningful to study the significance of adult asthma induced by respiratory irritants based on the mature TDI mouse model in our laboratory.The increased expression of RAGE receptors in airway epithelial cells and the aggregation of ?-catenin nuclei are important findings in TDI asthma,however the mechanism is still unknown.Studies have shown that JNK and RAGE play an important role in asthma,but the mechanism of the interaction between them and the role of ?-catenin in TDI has not been elucidated clearly.The purpose of this study was to explore the role and mechanism of JNK,RAGE,and b-catenin in TDI asthma.MethodsPart ?:The biopsy from asthma patients,lung tissue of TDI asthmatic animal models and cell lines were used to determine the levels of JNK phosphorylation,RAGE receptors and int.ranuclear ?-catenin.After collecting the airway tissue of patients with clinical non-asthma and severe asthma,building TDI-induced asthma mouse model,and stimulating 16HBE cell lines with TDI-HSA in vitro,we detected the expression levels of the RAGE receptor,P-JNK protein and the intranuclear ?-catenin in the airway epithelial cells,and analyzed the correlation among them.Part ?:Blocking JNK and RAGE signaling in TDI-induced asthma modelWith the method from previous researcher,we sensitized and challenged the experimental mice with TDI to first generate an asthma model.Inhibitors of RAGE(FPS-ZM1)or JNK(SP600125)were injected i.p.respectively before each challenge.airway reactivity to methacholine,airway inflammation,serum IgE,Th2-related cytokines,the expression of P-JNK,RAGE and the distribution of ?-catenin were analyzed to see if an asthma model is established Part ?:Establishing the RAGE promoter sequence and verifying the direct combination with the transcription factor SP-1.We predict the possible transcription factors that can be combined with the promoter of RAGE through the bioinformatics and fortunately we confirm that SP-1 can be combined with RAGE promoter by CHIP technic.ResultPart ?:The expression of JNK activation and RAGE from airway epithelial cells were increased obviously in severe asthma patients compared with normal individual,and were related positively with the degree of asthma.Part ?:We found that the expression of P-JNK and RAGE receptor in the airway epithelial cells from successfully established TDI-induced asthma mouse model were more enhanced than that from the controlled ones.We also found that the phosphorylation level of JNK and RAGE protein were elevated in 16HBE cells stimulated with TDI-HSA.We found that inhibitor of JNK and RAGE can reduce the TDI-induced asthmatic airway inflammation and airway hyperresponsiveness,possibly by regulating the distribution of ?-catenin in the bronchial epithelial cells.It is more important that JNK inhibitor suppressed ?-catenin nucleus gathering by regulating the RAGE expression,otherwise the phosphorylation of JNK was not affected by whether the RAGE knockout or not.Part ?:The RAGE mRNA of lung tissue,which can be inhibited by JNK inhibitor was increased in TDI-induced model in vivo.It reminds us that a particular transcription factor affected by P-JNK may activate RAGE promoter.We found that JNK activator can increase the RAGE mRNA expression,which proved that the phosphorylation of JNK could regulate the transcription of RAGE gene.We successfully prove that the transcription factor sp-1 could be directly combined with the RAGE promoter in living cells by CHIP technic.Once again We demonstrated that SP-1 can be activated by P-JNK and then regulate RAGE transcription in 16HBE cells.Conclusion1.The levels of JNK phosphorylation and RAGE expression in the airway epithelial cells of severe asthmatic patients and TDI-induced model,and in the 16HBE cells stimulated with TDI-HSA or JNK activator.2.JNK and RAGE were involved in the onset of TDI-induced asthma model and contributed to stabilize ?-catenin.3.JNK participates in the regulation of RAGE receptor expression through SP1.