The Function Of Six-transmembrane Epithelial Antigen Of Prostate 3 In Pathological Cardiac Hypertrophy

BackgroundCardiovascular disease is the number one killer endangering human beings.Pathological myocardial hypertrophy is a common complication of cardiovascular disease and a common pathological process in the progression of many cardiovascular diseases to heart failure.it has been listed as an independent risk factor leading to a significant increase in the incidence and mortality of cardiovascular disease,and has become a serious public health problem that can not be ignored.Clinically,chronic hypertension,coarctation of aortic valve,mitral or aortic regurgitation and some hereditary cardiomyopathy(such as hypertrophic cardiomyopathy)can produce pathological myocardial hypertrophy,which is characterized by hypertrophy of cardiomyocytes,significant increase in cardiac volume and significant thickening of ventricular wall thickness,and significant decrease in cardiac function(ejection fraction and left ventricular shortening fraction).Studies have shown that cardiomyocyte autophagy,non-coding RNAs,cell metabolism,proliferation,immune response,translation regulation and epigenetic modification are all involved in the occurrence of pathological myocardial hypertrophy.At present,clinically,it can only delay the transformation from pathological myocardial hypertrophy to heart failure,and there is no effective clinical drug for the treatment of myocardial hypertrophy.Therefore,exploring the key regulatory factors of the occurrence and development of myocardial hypertrophy and deeply understanding the pathogenesis of myocardial hypertrophy is the top priority of clinical drug research and development of myocardial hypertrophy and heart failure.Prostate six transmembrane epithelial antigen 3(STEAP3)is a kind of iron reductase,which can participate in important biological processes such as iron homeostasis,assembly and secretion of exosomes,apoptosis,proliferation and inflammation.It has been found that Steap3 gene deletion mice can attenuate ischemia-reperfusion injury by inhibiting the activation of transforming growth factor-activated kinase 1(Tak1)after ischemia-reperfusion(Imax R)injury.In addition,Steap3 gene deletion can attenuate the inflammatory response of macrophages mediated by Toll-like receptor 4(Toll-likereceptor4,TLR4).STEAP3 may be involved in a variety of signal transduction pathways regulating cardiac hypertrophy.However,the role of STEAP3 in the occurrence and development of pathological myocardial hypertrophy and heart failure is not clear.The purpose of this study was to explore the function of STEAP3 in the development of pathological myocardial hypertrophy.MethodIn order to verify the role and mechanism of STEAP3 in pathological cardiac hypertrophy,we have done the following work.First of all,at the cellular level,we cultured the neonatal rat cardiomyocyte(NRCM).After 24 hours of PE stimulation with adenovirus-infected primary cardiomyocytes over-expressed STEAP3,the size of cardiomyocytes was evaluated by ?-Actinin immunohistochemical staining,and the expression of protein and m RNA of cardiac fertilizer-related molecules was detected at the same time.At the animal level,we constructed cardiomyocyte-specific STEAP3 overexpression mice(TG)and compared with NTG of transgenic negative mice in the same litter,and performed ligation of transverse aortic constriction surgery(TAC)to induce cardiac hypertrophy in mice.The mice were divided into four groups as follows: NTG/Sham group(NTG mice,control group,n=10,sham operation,samples were taken in 4 weeks after aortic coarctation),TG/Sham group(Steap3-TG mice,control group,n=10,sham operation,samples were taken in 4 weeks after aortic coarctation);NTG/TAC(NTG mice,operation group,n=10,samples were taken in 4 weeks after aortic coarctation);TG/TAC(TG mice,operation group,n=10,samples were taken in 4 weeks after aortic coarctation).Four weeks after TAC operation,cardiac function and myocardial hypertrophy were evaluated,including echocardiographic evaluation of cardiac function(LVEDd,LVESd,FS and EF).Then the experimental mice were taken,and the gross indexes such as heart weight / body weight(HW/BW),lung weight / body weight(LW/BW)and heart / tibia length(HW/TL)were obtained.Then the sampled heart tissue was analyzed by pathological staining(the cross-sectional area of cardiomyocytes was evaluated by Hype staining and the degree of cardiac fibrosis was evaluated by PSR staining),and the molecular detection of cardiac tissue(protein and m RNA detection of cardiac hypertrophy and fibrosis-related molecules).Finally,we further explored it in order to understand the mechanism of STEAP3 in pathological myocardial hypertrophy.And identified the total proteins and phosphorylation levels of the key proteins in the MAPK signal pathway in the abovementioned cell samples and animal tissue samples by Western Blot.ResultIn the NRCM cell model infected with adenovirus STEAP3(Ad Steap3),it was found that without PE stimulation,the overexpression of STEAP3 did not significantly change the morphology of cardiomyocytes and the m RNA level of hypertrophy markers(ANP and Myh7).However,after PE stimulation,the primary cardiomyocytes of neonatal rats were significantly hypertrophic,and the response of STEAP3 overexpression to PE-induced cardiomyocyte hypertrophy was detected by immunofluorescence and real-time polymerase chain reaction(RT-q PCR).Compared with Ad GFP,the cardiomyocytes overexpressing STEAP3 were significantly smaller and the m RNA level of hypertrophy markers was significantly lower.In the heart-specific overexpressed STEAP3 mice,the cardiac function of these Steap3-TG mice was not significantly abnormal in the sham operation group.Four weeks after TAC operation,compared with control(NTG)mice,echocardiographic evaluation of left ventricular(LV)showed that left ventricular end-diastolic diameter(LVEDd)and left ventricular end-systolic diameter(LVESd)decreased,left ventricular short-axis shortening(FS)and ejection fraction(EF)increased in Steap3-TG mice.In addition,the ratio of HW/BW,LW/BW and HW/TL in STEAP3-TG mice was significantly lower than that in NTG mice.Cardiac pathological HE staining showed that compared with NTG mice,STEAP3-TG mice also showed smaller heart size and smaller cross-sectional area of cardiomyocytes in response to TAC-induced cardiac hypertrophy.At the same time,histological analysis of picric acid-Sirius scarlet(PSR)staining and statistics of left ventricular collagen volume showed that SREAP3-TG mice showed less fiber deposition than NTG mice.In addition,compared with NTG mice,the m RNA expression levels of hypertrophy markers(ANP,BNP and Myh7)and fibrosis markers(type I collagen ? 1,type III collagen ? 1 and connective tissue growth factor)in Steap3-TG treated Steap3-TG mice were significantly lower than those in TAC treated NTG mice.Conclusion1.STEAP3 attenuated cardiomyocyte hypertrophy induced by phenylephrine(PE);2.STEAP3 improves the impaired cardiac function of mice after aortic coarctation(TAC);3.STEAP3 improves myocardial hypertrophy and myocardial fibrosis induced by pressure overload in mice;4.STEAP3 inhibits the occurrence and development of pathological myocardial hypertrophy by inhibiting MAPK signal pathway.