Molecular Mechanism Of α1 Antitrypsin Inhibiting Ang Ⅱ Induced Endothelial Dysfunction In Aortic Dissection

Objective: Aortic dissection(AD)is one of the most fatal cardiovascular diseases which account for a large part of SCD.The main histopathological change of AD is vascular remodeling which acts as the degradation of elastin and collagen in the aorta medial wall.Dysfunction of aortic wall cells was considered to be the main cause of vascular remodeling in AD,such as apoptosis and inflammation.The role of aortic endothelial cells(AECs)in the pathogenesis of AD remains unclear.Previous studies have shown that α1antitrypsin(AAT)has a cytoprotective effect on vascular endothelial cells.This study mainly explored the expression of AAT in aortic tissue of AD patients and the mechanism of AAT in aortic endothelial cells.Methods:1.Quantitative polymerase chain reaction(q PCR)and Western blot(WB)were used to detect the levels of AAT and matrix metalloproteinases-9(MMP-9)expression in 6 AD patients and normal tissues.2.The m RNA content of AAT in endothelial cells was detected by q PCR to verify whether the plasmid transfection was successful to construct the cell model of AAT overexpression.Aortic dissection endothelial cells model was induced by angiotensin II(Ang II).3.Diaminophenyl indole(DAPI)/phalloidin double staining,CCK8 and EDU were used to detect the abnormal proliferation of aortic endothelial cells stimulated by Ang Ⅱ.4.The level of ROS(Reactive oxygen species)reflected the oxidative stress in endothelial cells,while LDH(Lactate dehydrogenase release)and flow cytometry were used to detected the necrotic of AECs.The cells were stained with fluorescence when them were studied the protective effect of α-1 antitrypsin.5.q PCR and WB were used to detect Caspase-3,MMP-1,9 in the cell model.6.Statistical analysis: all data of this subject were analyzed with mean ± SD methods.One-way ANOVA was selected on the comparison of multiple groups.t-test was studied on pairwise comparison.The histograms were made by Graphpad prism 9.0 and the difference of P < 0.05 was regarded as significant difference.Results: In the clinical sample,the expression levels of AAT and MMP-9 in aortic dissection were higher than those in normal control group,the outcome of Western blot showed the same trend.In the cells,Ang Ⅱ AAT overexpression treatment group had significant necrosis and apoptosis,and plasmid pretreatment group played a positive effect in interfering with oxidative stress of Ang Ⅱ,such as reducing the expression of ROS,LDH,Caspase-3.It also affected the expression of inflammation related proteins,such as MMP-1,9.In conclusion,our study shows that AAT is involved in the occurrence of AD,and AAT overexpression inhibited apoptosis,oxidative stress,and inflammatory response of Ang II induced in vascular endothelial cells.The endothelial cells also be involved in the dysfunction of aortic barrier and related to the occurrence of AD.Conclusion: 1.The AAT and MMP-9 levels were abnormal in AD patients.2.the endothelial cells inhibited oxidative stress,inflammation response and apoptosis induced by Ang Ⅱ.3.AAT overexpression can inhibit endothelial cell abnormalities,such as ROS production,LDH level,Caspase-3 and MMP-1,9 expression...