Study On MiR-155 Targeting AGTR1 In Monocrotaline-induced Pulmonary Hypertension

ObjectiveTo clarify the expression of miR-155 and angiotensin II receptor type 1(AGTR1)in pulmonary arteries of rats with monocrotaline-induced pulmonary hypertension and to investigate whether miR-155 can affect the proliferation of pulmonary artery smooth muscle cells by regulating the expression of AGTR1 in rat pulmonary artery smooth muscle cells.Methods50 healthy male Sprague-Dawley rats,aged 8-10 w,were randomly divided into 5 groups: blank control group,4d model group,7d model group,14 d model group,21 d model group.The control group received intraperitoneal injection of normal saline,and the other 4 groups.The pulmonary hypertension model was established by administering 50 mg/Kg of monocrotaline.In the control group and the 4 groups,the right ventricular pressure and systemic arterial pressure were measured at 0,4,7,14,and 21 d,respectively.After the completion of the test,the rats were sacrificed by bloodletting,the right heart mass index(RVMI)was calculated from the heart,and the lung tissues were observed by hematoxylin-yin red(HE)staining.The genes of miR-155 and AGTR1 in pulmonary arteries were detected by Real-time PCR.Western blot was used to detect the expression of AGTR1 protein in pulmonary arteries.The rat pulmonary artery smooth muscle cells were cultured in vitro,and the cells in good condition were taken for experiment.The following treatments were given and divided into 4 groups: blank control group(equal saline),pyrrolidine lily(MCTP)group,pyrrole wild lily base(MCTP)+Transfection of blank vector(miR-155-NC)group,pyrrophorus lily(MCTP)+ overexpressing miR-155(miR-155-mimic)group.The bioinformatics method predicts the target relationship between miR-155 and AGTR1.MTT assay detects cell growth and proliferation,luciferase reports analyze the regulation of miR-155 on AGTR1,qPCR detects miR-155 and AGTR1 gene expression,and Western blot analysis Protein expression of AGTR1.ResultsCompared with the control group,the right ventricular pressure(mRVP)and RVMI were significantly increased in the 14 d and 21 d model groups(P<0.05),but there was no significant difference in the systemic pressure between the groups(P>0.05).HE staining showed The modeling time progressed,the pulmonary artery lining gradually thickened,and vascular remodeling occurred.In the 21 st,the pulmonary artery lumen was narrow and the mesial hypertrophy.Compared with normal rats,miR-155 was induced by monocrotaline-induced pulmonary hypertension in rats.There was a low expression in the middle,while AGTR1 was highly expressed(P<0.05);and there was a negative correlation between the expression of miR-155 and AGTR1.Luciferase report assay confirmed that miR-155 specifically targeted to bind to AGTR1 gene caused a decrease in luciferase levels(P<0.05);MCTP-treated rat pulmonary artery smooth muscle cells increased cell proliferation,miR-compared with blank control group The expression of 155 decreased and the expression of AGTR1 increased(P<0.05).After the expression of miR-155 was overexpressed,the expression of miR-155 was detected,and the expression of AGTR1 gene and protein decreased,and the cell proliferation activity decreased(P<0.05).ConclusionsMCT induced the establishment of a rat model of pulmonary hypertension.The expression of miR-155 and AGTR1 in this model showed a negative relationship,and the expression levels of the two are related to the severity index of the response to pulmonary hypertension.MiR-155 can affect the proliferation of pulmonary artery smooth muscle cells by negatively regulating the expression of AGTR1 in pulmonary artery smooth muscle cells.