| Object: Hypertension is one of the most common chronic diseases and the criticalrisk factor of cardio-cerebrovascular disease. Heart is an important target ofhypertension. The most common pathological change of hypertensive heart is leftventricular remodeling. MiRNAs is a class of endogenous non-coding small RNAsthat controls gene expression. Studies have shown that miRNAs play important rolesin the regulation of proliferation, differentiation, and apoptosis in cells, and isinvolved in the pathological and physiological process of many diseases. MiR-31is akey miRNAs in heart. It’s been shown that miR-31is up-regulated in reconstructedheart tissue. However, it is still unknown whether miR-31could regulate the bloodpressure and improve the ventricular remodeling in SHRs. This project constructedlentivirus vectors carrying miR-31inhibition gene and examined the effect of miR-31on blood pressure and left ventricular remodeling in SHRs after transfection, andstudied whether LATS2is the target of miR-31and Hippo pathway is involved inmiR-31regulated blood pressure and left ventricular remodeling. The aim of thisstudy is to examine the pathogenesis of hypertension, and explore new strategies totreat hypertension.Methods:17-week-old SHRs were randomly divided into3groups:LV-miR-31-inhibition treatment (n=6), negative control (n=5), and blank group(n=5). Lentivirus vectors carrying miR-31inhibition gene (LV-miR-31-inhibition)and negative control were constructed. The treatment group was injected with150μlvirus solution of LV-miR-31-inhibition with a titer of1×108TU/ml via the tail vein.The control and blank groups were injected with an equal volume of negative controlvirus and enhanced infection solution (ENi.S.) respectively. The systolic bloodpressure was measured by tail cuff, and the structure and function indexes of leftventricular were observed by high frequency echocardiography (HFUS) for eachgroup animals. After3weeks all animals were sacrificed and heat tissue removed andcalculated the left ventricular mass index (LVMI). The cardiac morphology, mass, andfibrosis were examined by HE and Masson staining. The diameter and collagen volume of myocardial cells were calculated by image analysis software. Thetranscription of miR-31and LATS2, MST1/2, YAP, and TAZ in heart tissues wereexamined by qRT-PCR. The expression of LATS2was examined byimmunohistochemistry staining and Western blot analysis.Results: Lentivirus vectors carrying miR-31inhibition gene were constructed with atiter of8×108TU/ml. There is no significant change of blood pressure,LVPWT,IVST,LVEDD,LVESD,EF in negative control and blank control group at3weeks aftertransfection, and no detectable difference was observed in the two control groups.LV-miR-31-inhibition caused a significant decrease of blood pressure at3weeks（P<0.05）, and the HFUS indexes IVST, LVPW, LVEDD, LVESD was improveddramatically （P<0.05）. The blood pressure was lower in treatment group comparedwith that of negative control （P<0.05）, and the HFUS indexes IVSTd, LVPW,LVEDD, LVESD showed a significant difference （P<0.05）. The EF was notimproved in each groups. The LVMI of control and blank groups showed nodifference. Compared with control groups, the LVMI was decreased in treatmentgroup (（P<0.05）. The HE staining indicated that the left ventricular hypertrophy wasreversed after treatment, and the TDM decreased significantly （P<0.05）. Comparedwith the control groups, the collagen fiber deposition and CVF was decreased aftertreatment （P<0.05）. In treatment group, miR-31transcription was decreased（P<0.05）, and the transcription of LATS2, YAP, and TAZ was increased（P<0.05）.There’s no significant change of MST1/2transcription was observed. The LATS2expression was dramatically increased in treatment group when compared with thecontrol groups.Conclusions:Down-regulation of miR-31decreases blood pressure and effectivelyreverses left ventricular remodeling in SHRs. MiR-31may play an important role inheart tissue mediated by Hippo pathway using LATS2as a target. |
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