The Effect Of Store-operated Calcium Entry Associated Regulatory Factor On Cardiac Hypertrophy

Background and Objective:Cardiac hypertrophy is a common pathological process of many cardiovascular diseases?hypertension,heart failure,arrhythmia,etc.?.The researchs have confirmed that with the development of cardiac hypertrophy,the incidence of heart failure,arrhythmia,sudden death and other cardiovascular events significantly increased [1-2].Therefore,it is the focus and hot spot in the field of cardiovascular research to find the therapeutic target of cardiac hypertrophy.Intracellular calcium signal transduction pathway is one of the main signal pathways to induce myocardial hypertrophy,and the increasing of intracellular calcium calcium ion(Ca²⁺)is the basic signal of myocardial hypertrophy.Studies have shown that stromal interacting molecule 1 interacts with Orai1?Calcium release-activated calcium channel protein1?,causing extracellular Ca²⁺ influx.In the process of cardiomyocyte hypertrophy induced by angiotensin ??angiotensin ?,Ang ??and phenylephrine?PE?,we found that STIM1 expression was significantly up-regulated and SOCE was over-activated.After knock down of STIM1 and Orai1,the status of SOCE activation and cardiomyocyte hypertrophy induced by Ang? and PE were improved.The expression of STIM1 in hypertrophic myocardium caused bypressure overload was significantly increased,when knocking down the expression of STIM1 in myocardium,it could significantly delay the progress of myocardial hypertrophy.It showed that STIM1 and Orai1 play an important role in the occurrence/development of myocardial hypertrophy.In addition to STIM1 and Orai1,a novel protein discovered recently: store-operated calcium entry associated regulatory factor?SARAF?.It promotes the dissociation of STIM1 and Orai1,and prevents excessive intracellular Ca²⁺ concentration.We hypothesized that long-term stress overload,the expression of SARAF in the myocardial cells decreased,leading to intracellular Ca²⁺ concentration continued to rise,causing myocardial hypertrophy and cardiac hypertrophy;by inhibiting myocardial Ca²⁺ overload and reducing myocardial hypertrophy,the upregulation of SARAF expression can delay the progress of myocardial hypertrophy.In order to confirm this hypothesis,we constructed a model of cardiac hypertrophy induced by cardiac hypertrophy in C57 BL/6J mice,and to find the effect of SARAF on cardiac hypertrophy induced by Ang II.Methods:The study is divided into two parts: animal experiment and cell experiment.Animal experiment: 8 week old male C57 BL/6J 40 mice?weighied about28-30g?,were randomly divided into 4 groups: sham operation group?group Sham?and pressure overload group?CAA group?,empty virus gene transfection group?CAA+NC group?,SARAF gene transfection group?CAA+SARAF group?.CAA group,CAA+NC group and CAA+SARAF groupunderwent abdominal aortic constriction surgery,CAA+NC group and CAA+SARAF group respectively transfected empty virus?Lenti-GFP?and SARAF gene lentiviral?Lenti-hSARAF?.Cell experiment: myocardial cells of C57 BL/6J mice were divided into four groups as control group?group control?,angiotensin induced group?Ang? group?,empty virus gene transfection group?Ang?+NC group?,SARAF gene transfection group?Ang II +SARAF group?,Ang II +NCg group and Ang II+SARAF group respectively transfected empty virus?Lenti-GFP?and SARAF gene lentiviral?Lenti-hSARAF?,24 h incubation,followed by Ang II?final concentration 200 umol/l?intervention,Ang II group,Ang II +NCgroup,Ang II +SARAFgroup for 72h1.Detection of myocardial hypertrophy in mice by ultrasonography2.Carotid artery cannula was used to measure the blood pressure of each group3.Weighted mice weight and heart weight,calculated the heart / body weight ratio.4.Compared the mice heart size of each group.5.Observed the size of cells in myocardial tissue by HE staining.6.Measured the expression of Stim1,Orai1 and SARAF in hypertrophic myocardium and myocardial cells by qPCR and Western-blotting.7.Identified myocardial cells by ?-actin immunofluorescence staining,observed the size of myocardial cells in each group;Results:1.In myocardial tissue cuased by overload hypertrophy,the expression of SARAF was decreased and the expression of STIM1 and Orai1 was increased;2.Upregulation of SARAF expression can inhibit myocardial hypertrophy in mice.3.The expression of SARAF in hypertrophic cardiomyocytes induced by Ang? was significantly decreased.4.Upregulation of SARAF expression can reduce cardiomyocyte hypertrophy induced by Ang ?.Conclusions:SARAF may play a role in the regulation of cardiac hypertrophy,and raising the regulation of SARAF expression can improve myocardial hypertrophy induced by pressure overload.