Effect And Its Mechanisms Of Urotensin II On The Expression Of Monocyte Chemoattractant Protein-1 In Rat Aortic Adventitial Fibroblasts

Background: Human Urotensin II (UII) is an 11 amino acid cyclic peptide originally isolated from the goby fish. The amino acid sequence of UII is exceptionally conserved across most vertebrate taxa, sharing structural similarity to somatostatin. UII binds to a class of G-protein coupled receptor known as GPR14 or the urotensin receptor (UT). UII and its receptor UT are widely expressed throughout the cardiovascular, pulmonary, central nervous, renal and metabolic systems. UII is generally agreed to be the most potent endogenous vasoconstrictor discovered to date. UII also exerts a wide range of actions in other systems such as proliferation of vascular smooth muscle cells, fibroblasts and cancer cells. It also enhances foam cell formation, chemotaxis of inflammatory cells, inotropic and hypertrophic effects on heart muscle. Many of the major diseases, including cardiovascular disease, such as atherosclerosis, cardiac hypertrophy and heart failure, are widely recognized as inflammatory diseases. Many research support that adventitial fibroblasts may be an early event with a significant role during the development of vascular inflammatory diseases. Monocyte chemoattractant protein-1 (MCP-1) plays a critical role in the development of cardiovascular diseases. But, its mechanisms of urotensin II on the expression of monocyte chemoattractant protein-1 in rat aortic adventitial fibroblasts are discorvered.Objective: To investigate the effect of urotensin II(UII) on the expression of monocyte chemoattractant protein-1 in rat aortic adventitial fibroblasts, and to study the signal transduction pathways.Methods:①In cultured adventitial fibroblasts isolated from aorta of adult Sprague-Dawley rats, Growth-arrested adventitial fibroblasts were incubated in serum-free medium with urotensin II (10-10-10-7mol/L) for different lengths time(1h, 3h, 6h, 12h, 24h). Then RT-PCR and Western Blotting was used to detect the expression of MCP-1, ELISA was used to detect the secretion of MCP-1②Adventitial fibroblasts that have been pretreated by some inhibitors of signal transduction pathways for 30 min were incubated by 10-8mol/L urotensin II for 3h and 12h, then the MCP-1 expression were evaluated by RT-PCR and ELISA respectively. Results: Urotensin II induced monocyte chemoattractant protein-1 expression in a dose-dependent and time-dependent manner, with maximal effect at a concentration of 10-8 mol/l at 3h (in the level of mRNA), 12h (in the level of protein secretion) or 24 h (in the level of protein); These effects were inhibited by the UII receptor antagonist SB710411 (10-6 mol/l), Rho protein kinase inhibitor Y27632 (10-5 mol/l), protein kinase C inhibitor H-7 (10-5 mol/l), mitogen-activated protein kinase inhibitor PD98059 (10-5 mol/l), calcineurin inhibitor Cyclosporine A (10-5 mol/l) and Ca2+ channel blocker nicardipine (10-5 mol/l), The inhibition efficiencies are 64.23%,39.14%,70.76%,68.31%,65.92%和63.47% respectively ( P<0.01).Conclusion: Urotensin II may stimulate the expression of monocyte chemoattractant protein-1 in rat aortic adventitial fibroblasts through the protein kinase C, mitogen-activated protein kinase, Ca2+ channel, calcineurin and Rho kinase signal transduction pathways, contributing to the vascular inflammation.