| BackgroundAtherosclerosis(As)is a chronic and complex disease,and its related cardiovascular and cerebrovascular diseases seriously endanger human health and life.It is one of the major diseases causing human death worldwide.The pathophysiological process of As is mainly characterized by phenotypic changes of endothelial cells and smooth muscle cells.Various factors are involved in the development of As,and shear stress abnormalities play an important role in the formation of As lesions.Recent studies have found that Endothelial-to-Mesenchymal transition(EndMT)plays a key role in the development of the cardiovascular system and is an important factor in the development of As.EndMT is a special type of Epithelial-mesenchymal transition(EMT),which refers to the process of endothelial cells transforming into mesenchymal cells under the influence of stimulating factors.During this process,endothelial cells gradually lose their unique characteristics.Morphology,structure and function,while a small part of the proliferating mesenchymal cells in the As plaque comes from the vascular membrane,which is largely formed by the transformation of the endothelial cells of the intima into the endothelium.Studies have shown that abnormal shear stress can directly affect endothelial cells,and participate in the formation and development of As through local mechanical transduction and ultimately cause different signaling pathways to activate.Therefore,it is very necessary to explore the mechanism for the development of As and seek new therapeutic targets..Hydrogen sulfide(H2S)is the third gas signal molecule discovered after nitric oxide and carbon monoxide.The gas signal molecule H2S inhibits inflammation,improves endothelial cell function,and relaxes blood vessels.It is an important endogenous protective molecule.Many scholars at home and abroad have studied and researched many years of research results,indicating that H2S plays an important antagonistic role in the development of As.In the early stage of the research group,it has been confirmed in mice that H2S can inhibit EndMT and As lesions caused by abnormal shear stress,and its mechanism of action is related to the down-regulation of TGF-?1/Smad.This study was to further investigate the effect of H2S on endothelial stromal transformation in human umbilical vein endothelial cells(HUVECs)under low shear stress and to investigate the expression of related proteins and the expression of downstream transcription factors after the addition of signaling pathway inhibitors.PurposeTo observe the effect and mechanism of hydrogen sulfide on endothelial mesenchymal transition of human umbilical vein endothelial cells(HUVECs)under low shear stress.MethodIn this experiment,endothelial cells were treated with a parallel plate flow chamber system to cause low shear stress(5dyne/cm~2).The cells were randomly divided into 4 groups:blank control group,low shear stress group,low shear stress+NaHS group(100?mol/L),low shear stress+PPG group(5 mmol/L).After 5 hours of treatment in a parallel plate flow chamber system,the migration ability and morphological changes of endothelial cells were observed,the expression of CSE protein was detected by Western blotting,and endothelial cell markers(CD31,VE-were detected by Western blotting and immunofluorescence).Changes in the expression of cadherin and interstitial cell markers(?-SMA).After adding TGF-?receptor kinase inhibitor SB431542,the expressions of TGF?1,TGF?RII,pSMAD2/3 and their transcription factors Snail and Slug were detected by Western blotting and immunofluorescence.Experimental results:1.The migration experiment showed that the mobility of the low shear stress group was 10.59%(P<0.05)compared with the control group,and the cell mobility of the NaHS group was reduced by 5.58%(P<0.01)compared with the low shear stress group.,while the cell migration rate of the PPG group was increased by 6.88%(P<0.01).2.The results of Western blotting showed that compared with the Control group,the expression of CSE in the low shear stress group decreased by 16.67%(P<0.05),while compared with the low shear stress group,the CSE protein level in the NaHS group increased significantly by 29.33%(P<0.01),while the CSE protein expression level of the PPG group decreased by 12.98%(P<0.01).3.The results of Western blotting showed that compared with the Control group,the expression levels of CD31 and VE-cadherin in the low shear stress group decreased by 17.81%and 12.11%,respectively (P<0.05),and the expression level of?-SMA protein increased by 21.77%(P).<0.05),compared with the low shear stress group,the levels of CD31 and VE-cadherin in NaHS group increased by 21.49%(P<0.05)and 24.52%(P<0.01),respectively,and the expression level of?-SMA protein decreased by 13.76%.(P<0.05),the expression levels of CD31 and VE-cadherin in PPG group decreased by 12.29%(P<0.01)and 26.09%(P<0.05),respectively,and the expression of?-SMA protein increased by 8.79%(P<0.01).Immunofluorescence results showed that compared with the control group,the expression of CD31 was decreased and the expression of?-SMA protein was increased in the low shear stress group,while the expression of CD31and?-SMA were increased in the NaHS group compared with the low shear stress group,while the expression of CD31 in the PPG group was significantly reduced and the expression of?-SMA was increased.4.The expressions of TGF?1,TGFRII,pSMAD2/3,Snail and Slug protein in the low shear stress+SB431542 group were 27.19%,18.92%,16.86%,30.25%and 18.21%,respectively(P<0.05).Compared with the low shear stress+SB431542 group,the expression of TGF?1,TGFRII,and pSMAD2/3 protein in the low shear stress+SB431542+NaHS group decreased by 22.19%,25.86%,and 31.85%,respectively(all P<0.05),Snail,The expression of Slug protein decreased by 17.22%and 18.31%,respectively(P<0.01),while the expression of TGF?1,TGFRII,pSMAD2/3,Snail and Slug protein in low shear stress+SB431542+PPG group increased by 18.94%and12.35%,respectively.19.99%,12.35%,and 5.79%(both P<0.05).Conclusion:Hydrogen sulfide can inhibit endothelial mesenchymal transition of human umbilical vein endothelial cells under low shear stress,and its mechanism is related to inhibition of TGF-?1/TGF?RII/Smad2/3 signaling pathway. |
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