Influence Of Angiotensin-(1-7) On The Expression Of E-selectin Induced By Angiotensin Ⅱ And Its Mechanism In Vascular Endothelial Cells

There is a network of Inflammation and Coagulation in human body,which interact with each other in many aspects.Inflammation can enhance human coagulation and in turn,the latter also promote the inflammation,which finally forms auto-amplification cascading effect.If not be interfered,It may induce disseminated intravascular coagulation(DIC),organ dysfunction or death.E-selectin(Es) is an important factor that participates in human eary inflammatory response.Es initiates human inflammation by mediating leukocyte rolling and stranded in pro-inflammation stage and the inflammatory response is the main cause of thrombosis.When resting,endothelial cells have little content of Es.However,if stimulated by many inflammatory mediators such as interleukin-1(IL-1),tumor necrosis factor-α(TNF-α), angiotensinⅡ(AngⅡ),lipopolysaccharide(LPS) and so on,the expression of Es will be increased a great deal in endothelial cells.Renin-angiotensin system(RAS) is one of the most important regulative systems in human body,and plays a significant role in maintaining homeostasis.Recently many reports indicated that AngⅡhas not only the action of boosting blood pressure,but also affects the balances of coagulation-anticoagulation and fibrinolysis-antifibrinolysis. It is widely accepted that AngⅡparticipates in the development of atherosclerosis and acute cerebrocardiac infarction.Angiotensin-(1-7)[Ang-(1-7)]is another important peptide,which is the product of angiotensinⅠand/or AngⅡconverted mainly by ACE2. The actions of Ang-(1-7)are almost opposite to AngⅡ,for example it can diastole blood vessel and inhibit cell proliferation.Therefore the two peptides of RAS collaborate to maintain body homeostasis.It was reported that AngⅡcan induce the expression of Es,but until now it remains unclear whether Ang-(1-7) also can inhibit the expression of Es induced by AngⅡ.AIM The purposes of this study were to observe the effects of Ang-(1-7)on the expression of Es induced by AngⅡin human umbilical vein endothelium derived cell line(HUVEC)s and to explore mechanisms of Ang-(1-7) on the expression of Es induced by AngⅡ.Methods HUVECs were cultured in DMEM.THP-1 were cultured in RPMI-1640.The adherence rate was determined with chromometry.Es antigen was measured by ELISA Kit.Es mRNA was examined by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR).Immunohistochemical analysis was performed to evaluate the activation of NF-κB.Results①Compared with the control,a gradual increase in Es antigen(r=0.965,P＜0.05),Es mRNA(P＜0.05) and the adherence rate (r=0.972,P＜0.05)were observed in HUVECs stimulated with increasing concentration of AngⅡ(10^-10～10^-6mol/L),and peaked at 10^-7mol/L.②Ang-(1-7)(10^-9～10^-6mol/L) alone could not affect the adherence rate and the expression of Es in HUVECs(P＞0.05).When pretreated with Ang-(1-7)(10^-9～10^-6mol/L),it inhibited the effects of AngⅡon Es antigen(r=-0.943,P＜0.05),mRNA(P＜0.05) and the adherence rate(r=-0.925,P＜0.05) in dose-dependent manner,and 10^-6mol/L was the strongest concentration.③L-NAME alone,which is the inhibitor of NOS,had no marked effects on Es antigen,Es mRNA and the adherence rate in HUVECs,but L-NAME significantly inhibited the effects of Ang-(1-7)on Es expression induced by AngⅡ(p＜0.05).④Immunohistochemical analysis demonstrated NF-κB translocation from cytoplasm to the nucleus after treatment of endothelial cells with AngⅡand the effect of NF-κB translocation induced by AngⅡwas inhibited by Ang-(1-7).Conclusion The present data suggested that①AngⅡcould induce the expression of Es in vascular endothelial cells,and Ang-(1-7) could inhibit this effect at mRNA level.②NO pathway participates in the inhibitory effects of Ang-(1-7) on the expression of Es induced by AngⅡ.③NF-κB translocation plays an important role in AngⅡ-induced Es expression.Ang-(1-7) can inhibit NF-κB translocation induced by AngⅡ.