Up-regulation Of Endothelin Receptor Expression Via Activation Of Canonical Nuclear Factor-κB Pathway Plays Crucial Role In Inflammation-induced Phenotypic Modulation Of Vascular Smooth Muscle Cells

Background:The phenotypic modulation of vascular smooth muscle cells(VSMC)under inflammatory state is a key factor in atherosclerotic cardiovascular diseases.The endothelin(ET)receptors play important role in the physiological function of arteries.The expression of ET receptor type A(ETA)and B(ETB)is upregulated in cardiovascular diseases.However,abnormal expression of ET receptors under inflammatory status in VSMC has not yet been well studied,and the involvement of inflammation-induced activation of nuclear factor-κB(NF-κB)pathways remained unclear.Additionally,and the effect of ET receptor expressional alteration on inflammation-induced phenotypic modulation of VSMC has not been reported.Methods:The mechanisms of ET receptor alteration and its role in phenotypic modulation of VSMC under inflammatory status were studied by using approaches of pharmacology,cell biology,molecular biology,and bioinformatics.Results:The expression of ETA and ETB receptors was increased in both immediate and chronic inflammation rat models,paralleled with elevated responsiveness of mesenteric arteries to ET receptor agonists and augmented serum level of pro-inflammatory cytokine tumor necrosis factor-α(TNF-α).Treatment of TNF-α in vitro resulted in remarkable increased expression of ETA and ETB receptors in intact arteries,with enhanced receptor-mediated vasoconstriction,and in cultured A7R5 cells,with enhanced promotor activity.Inhibitory experiments and molecular biological experiments revealed that,the activation of canonical NF-κB pathway,and not that of non-canonical pathway,was responsible for the up-regulation of ETA and ETB receptor expression.TNF-α in combination with ET-1 resulted in enhanced proliferation and migration of A7R5 cells,and 105 differentially expressed genes(DEGs),among which 22 were further identified to be reversed by specific antagonists for ETA receptor(BQ123)and ETB receptor BQ788.Bioinformatics analysis indicated that the up-regulation of ET receptor expression might be involved in important process of inflammatory response,cytokine receptor binding,and so on,while protein-protein interaction network CCL5/CCR6/CXCL6/CXCL12 was predicted.Conclusions:In the VSMC under inflammatory status,activation of canonical NF-κB pathway resulted in up-regulated expression of ETA and ETB receptor.The latter played an important role in inflammation-induced phenotypic modulation of VSMC,and might thus contribute to the progression of atherosclerotic cardiovascular diseases.