The Preliminary Study Of Autophagy On Vascular Endothelial Cells ENOS And ET-1Induced By Steady Laminar Shear Stress

【Objective】Vascular endothelial cell function responds to steady laminar shear stress;however, the underlying mechanisms are not fully elucidated. In the present study, weexamined the effect of steady laminar shear stress on vascular endothelial cellautophagy and its role in steady laminar shear stress-medicated endothelial cell nitricoxide synthase (eNOS) and endothelin-1(ET-1) expression using an ex vivo perfusionsystem.【Methods】Human umbilical vein endothelial cells were placed in an ex vivo cell perfusionsystem and common arteries of New Zealand white rabbits were placed in an ex vivoorganize perfusion system under static conditions (0dyne/cm2) or steady laminarshear stress (5or15dyne/cm2) for1h. Western blot and RT-PCR were used to detectBcline-1, LC3, p62, ET-1and eNOS protein and mRNA expression. After treatmentwith steady laminar shear stress for1h, endothelial cells were treated withbafilomycin A1or pepstatin A for2h and the LC3protein expression was measured.Furthermore, human vascular endothelial cells or New Zealand white rabbits treatedwith autophagy inducer rapamycin or autophagy inhibitor3-MA followed with steadylaminar shear stress for1h, RT-PCR and western blot were used to detect the eNOSand ET-1mRNA and protein expression, respectively.【Results】In both ex vivo perfusion human umbilical vein endothelial cells and vascular vessel segment, steady laminar shear promoted eNOS expression and inhibited p62and ET-1expression. Under steady laminar shear stress, autophagy marks Bcline-1and LC3expression was increased and the autophagy dysfunction marker p62contentwas decreased. When pretreated with rapamycin, steady laminar shear stress-inducedup regulation of eNOS and the downregulation of ET-1was further strengthened.However, pretreatment with3-MA, the upregulation of eNOS was obviously inhibitedand the downregulation of ET-1induced by steady laminar shear stress was partiallyreversed.【Conclusions】Autophagy is promoted under steady laminar shear stress, which contributes tothe upregulaiton of eNOS and the downregulation of ET-1induced by steady laminarshear stress.