The Expression And Positive Feedback Mechanism For Disease Of HIF-1? And MUC5AC Genes In Epithelial Cells Of Chronic Obstructive Pulmonary Disease

BackgroundChronic obstructive pulmonary disease(COPD)is a common respiratory system disease with high prevalence,resulting in high rate of disability and mortality.Global Initiative for Chronic Obstructive Lung Disease(GOLD)defines COPD as a preventable and treatable disorder,characterized by durable and not fully reversible airflow limitation,associated with enhanced chronic inflammation in airway and lung induced by harmful air or particles.High level secretion of airway fluid is a significantly casual factor of multiple chronic airway inflammatory progression.MUC5 AC is the most important secretion protein in airway.Studies have shown that its secretion mechanism involves GPCR,tyrosine protein kinase and non-receptor tyrosine kinase signaling pathways.Amongst them,PI3 K signaling pathway plays a significant role in the secretion of MUC5 AC.Hypoxia inducible factor-1(HIF-1)is an important transcriptional factor mediating hypoxia responses and plays a significant role in mediating hypoxia responses.Studies have shown that not only HIF-1? plays a significant role in regulating oxygen balance,its stability is essential for regulating HIF-1 expression.And it can also induce the expression of over 100 genes which are involved in hypoxia adaption and inflammation.A study has shown that HIF-1? is associated with lung inflammation of COPD and that it's also involved in vascular remodeling of lung by upregulating the expression of nitric oxide synthase.Thus,it participated in the pathogenesis of COPD.In recent years,the interest of its role in allergic inflammation has been increased.Previous studies have shown that HIF-1? could regulate multiple inflammatory factors and hence influence inflammation through PI3K/AKT,MAPK pathway.And the PI3K/AKT pathway activation is less of a study that promotes the expression of MUC5 AC.Therefore,this study attempts to discuss the regulatory mechanism of HIF-1? in chronic obstructive pulmonary disease,and its effect on the development of COPD.ObjectiveTo determine the expression level of HIF-1? and MUC5 AC in patients suffered from COPD,investigate the mechanism of HIF-1? regulating MUC5 AC and assess its impact to the progression of COPD MethodsWe collected bronchialveolar lavage fluid samples from 71 cases.Amongst them,59 cases were certified for COPD and 12 cases were normal lung function from other patients because of other diseases hospitalized in our hospital.Realtime PCR and Western blot were employed to determine the mRNA and protein expression levels of HIF-1?,TGF-? and MUC5 AC in the samples.Then we analyzed the association of HIF-1? and MUC5 AC expression levels.We also employed human embryo lung epithelial cells as the cell model and treated them with CoCl2 which is the agonist of HIF-1? and 740Y-P which is the agnonist of PI3 K.Then Realtime PCR and Western blot were employed to detect the level of mRNA and protein of HIF-1?,EGFR,AKT and MUC5 AC.And we explore the control mechanisms of HIF-1? and PI3 K for MUC5 AC.Results1.The mRNA and protein levels of HIF-1?,TGF-? and MUC5 AC in samples from COPD cases are significantly higher compared with control cases(P<0.05).The mRNA expression of HIF-1? is positively associated with that of MUC5 AC.2.After successful cell modeling of human embryo lung epithelial cells in hypoxia state by using CoCl2,Realtime PCR and Western blot results have shown that the expression of HIF-1?,EGFR,AKT and MUC5 AC are significantly higher than the control group(P<0.05).After treated with 740Y-P in human embryo lung epithelial cells,the Realtime PCR and Western blot tests found that the level of phosphorylation of AKT was increased after the PI3 K was activated,and both the mRNA and protein levels of MUC5 AC increased significantly.The RNA and protein levels of HIF-1? and EGFR are elevated too.Conclusion1.The mRNA and protein levels of HIF-1?,TGF-? and MUC5 AC in the COPD group are higher than those in the control group.The mRNA expression of HIF-1? is positive correlation with that of MUC5 AC.HIF-1?,TGF-? and MUC5 AC all participate in the pathologic process of chronic obstructive pulmonary disease.2.CoCl2 inducing NCI-H1563 cell line into a hypoxia state causes the elevated expression of HIF-1?,thus upregulates EGFR and subsequently activates PI3 K.Finally,the expression of MUC5 AC is elevated by this process.740Y-P can activate EGFR-PI3K-AT signaling pathway and results in the elevation of MUC5 AC and finally it can upregulate the expression of HIF-1? in a feedback way.They can together promote inflammation and mucin secretion.