Preliminary Study On Regulation Of CCL2 By Shh Signaling Pathway

BackgroundBronchial asthma(asthma)is a chronic,nonspecific inflammatory disease,which have failed to be cured yet with various drugs.There were several studies which have showed that Sonic hedgehog(Shh)signaling pathway relates to the differentiation and development of fetal lung,formation of fetal lung germ,respiratory epithelia cells and vessels in mammals,as well as the differentiation of lung stroma and tracheal cartilage.C-C motif chemokine ligand 2(CCL2)is a monocyte chemotactic factor which can activate monocyte and recruit it to the lung turning to be a bronchial alveolar macrophages.However,the molecular mechanism of Shh signaling pathway and the pathogenesis of CCL2 in cells associated with asthma is not yet clear during the pathogenesis of bronchial asthma.MethodsIn this study,HBE cells and RAW 274.7 cells were treated by recombinant human Shh protein or pretreated by lipopolysaccharide.The expressions of Shh signaling,CCL2,as well as downstream molecules were detected by western blot and qPCR with the intention to detect changes of Shh signaling pathway and CCL2 in both cells and the primary study of Shh signaling pathway regulating CCL2 in asthma.Results1.Activation of Shh signaling pathway in human bronchial epithelial cells:Compared with the control group,pretreatment with LPS can promote the expression of Shh in HBE cells;recombinant human Shh protein can increase the expression of Shh protein and promote the expression of Smo,Ptch1 and Gli1 mRNA in cells.2.Activation of Shh signaling pathway in macrophages:Compared with the control group,LPS pretreatment can increase the expression of Ptch1 mRNA in cells;recombinant Shh promoted the expression of the molecules(e.g.Ptch1 and Gli1 mRNA)and decreased the expression of Smo mRNA in RAW 264.7 cells.3.The expression of CCL2 and downstream molecules in cell:LPS pretreatment and recombinant human Shh protein can promote the expression of CCL2 mRNA in both HBE cells and RAW 264.7 cells,and LPS can also promote the expression of CCR2 mRNA and MCPIP in RAW 264.7 cells.Conclusions1.Recombinant human Shh protein can promote the activation of Shh signaling pathway in both HBE cells and RAW 264.7 cells,and can significantly upregulate the expression of CCL2.2.LPS pretreatment can not only promote the expression of Shh induced by recombinant human Shh in HBE cells,but also can acitvate Shh signaling system and CCL2 signaling system in RAW 264,7 cells.3.The pathogenesis of asthma may be related to the upregulation of CCL2 expression induced by Shh signaling pathway.