Effects of combination of irbesartan and perindopril on calcineurin expression and sarcoplasmic reticulum Ca^(2+)-ATPase activity in rat cardiac pressure-overload hypertrophy

Aim： To observe effects of angiotensin （Ang） II receptor antagonist （ATI） irbesartan and angiotensin-converting enzyme （ACE） inhibitor perindopril on rat myocardium calcineurin expression and sarcoplasmic reticulum Ca^2＋-ATPase activity in the model of pressure-overload cardiac hypertrophy. Methods： Forty male adult Sprague Dawley rats were divided into 5 groups One group was treated by sham operation; four groups were myocardium hypertrophy cases caused by banding aortic above renal artery. Drugs were given one week after operation. Group 1： sham group, rats （n=8） were gavaged with normal saline 2 ml/（kg·d） （ig）; Group 2： control group, rats （n=8） were treated with normal saline 2 ml/（kg·d） （ig）; Group 3： rats （n=8） were given perindopril 2 mg/（kg·d） （ig）; Group 4： rats （n=8） were treated with irbesartan 20 mg/（kg·d） （ig）; Group 5： rats （n=8） were given irbesartan 20 mg/（kg·d） plus perindopril 2 mg/（kg·d） （ig）. Morphometric determination, calcineurin expression and sarcoplasmic reticulum Ca^2＋-ATPase activity were done at the end of 6 week of drug intervention. Expression of calcineurin in myocardium was detected by immunohistochemistry. Results： Left ventricular mass index （LVMI）, transverse diameter of myocardial cell （TDM）, calcineurin activity were remarkably decreased after drug intervention and this decrease was most remarkable in the combination drug therapy group. Sarcoplasmic reticulum Ca^2＋-ATPase activity was increased after drug intervention, especially in the combined drug therapy group. Calcineurin expression in myocardium was remarkably decreased after drug intervention. LVMI was positively correlated with TDM and calcineurin, negatively correlated with sarcoplasmic reticulum Ca^2＋-ATPase. Conclusion： These data suggest that irbesartan and perindopril inhibit cardiac hypertrophy through the increased activity of sarcoplasmic reticulum Ca^2＋-ATPase and decreased expression of calcineurin. Their combination had better effects on regressing of ventricular hypertrophy.

Nardosinone Protects H9c2 Cardiac Cells from Angiotensin Ⅱ-induced Hypertrophy

Pathological cardiac hypertrophy induced by angiotensin Ⅱ （Ang Ⅱ ） can subsequently give rise to heart failure, a leading cause of mortality. Nardosinone is a pharmacologically active compound extracted from the roots ofNardostachys chinensis, a well-known traditional Chinese medicine. In order to investigate the effects of nardosinone on Ang Ⅱ-induced cardiac cell hypertrophy and the related mechanisms, the myoblast cell line H9c2, derived from embryonic rat heart, was treated with nardosi- none （25, 50, 100, and 200μmol/L） or Ang Ⅱ （1 μmol/L）. Then cell surface area and mRNA expression of classical markers of hypertrophy were detected. The related protein levels in PI3K/Akt/mTOR and MEK/ERK signaling pathways were examined by Western blotting. It was found that pretreatment with nardosinone could significantly inhibit the enlargement of cell surface area induced by Ang Ⅱ. The mRNA expression of ANP, BNP and 13-MHC was obviously elevated in Ang Ⅱ-treated H9c2 cells, which could be effectively blocked by nardosinone at the concentration of 100μmol/L. Further study revealed that the protective effects of nardosinone might be mediated by repressing the phosphorylation of related proteins in PI3K/Akt and MEK/ERK signaling pathways. It was suggested that the inhibitory effect of nardosinone on Ang Ⅱ-induced hypertrophy in H9c2 cells might be mediated by targeting PI3K/Akt and MEK/ERK signaling pathways.

Decorin Induces Cardiac Hypertrophy by Regulating the CaMKⅡ/MEF-2 Signaling Pathway In Vivo

Objective:Cardiac hypertrophy is an adaptive reaction of the heart against cardiac overloading,but continuous cardiac hypertrophy can lead to cardiac remodeling and heart failure.Cardiac hypertrophy is mostly considered reversible,and recent studies have indicated that decorin not only prevents cardiac fibrosis associated with hypertension,but also achieves therapeutic effects by blocking fibrosis-related signaling pathways.However,the mechanism of action of decorin remains unknown and unconfirmed.Methods:We determined the degree of myocardial hypertrophy by measuring the ratios of the heart weight/body weight and left ventricular weight/body weight,histological analysis and immunohistochemistry.Western blotting was performed to detect the expression levels of CaMKⅡ,p-CaMKⅡ and MEF-2 in the heart.Results:Our results confirmed that decorin can regulate the CaMKⅡ/MEF-2 signaling pathway,with inhibition thereof being similar to that of decorin in reducing cardiac hypertrophy.Conclusion:Taken together,the results of the present study showed that decorin induced cardiac hypertrophy by regulating the CaMKⅡ/MEF-2 signaling pathway in vivo,revealing a new therapeutic approach for the prevention of cardiac hypertrophy.

L-carvone attenuates myocardial injury and dyslipidemia in rats with isoproterenol-induced cardiac hypertrophy

Objective:To explore the therapeutic efficacy of L-carvone from Mentha spicata L.leaf extracts against isoproterenol-induced cardiac hypertrophy in rats.Methods:Isoproterenol(5 mg/kg)was injected intraperitoneally into rats for one month to induce cardiac hypertrophy.L-carvone(25 and 100 mg/kg)was administered orally to treat cardiac hypertrophy.The cardioprotective activity of L-carvone was evaluated by electrocardiogram,histopathological analysis as well as determination of biochemical parameters and enzymatic markers.Results:L-carvone from Mentha spicata L.at 25 and 100 mg/kg ameliorated isoproterenol-induced cardiac hypertrophy,as evidenced by reduced QRS interval on electrocardiogram,and decreased heart weight and heart index.In addition,both doses of L-carvone markedly lowered the levels of glucose,total protein,low-density lipoprotein cholesterol,aspartate transaminase,alanine transaminase,lactate dehydrogenase,creatine kinase MB,troponin-Ⅰ,N-terminal pro-B type natriuretic peptide and triglycerides while increasing high-density lipoprotein cholesterol and lipase level(P<0.05).Moreover,L-carvone alleviated contraction band necrosis,and reorganized the myofibrils with normal striations and myocytes as well as normal nuclei in cardiac histoarchitecture of rats with isoproterenol-induced cardiac hypertrophy.Conclusions:L-carvone from Mentha spicata L.leaf extract can restore abnormal cardiac function and may be further explored as a therapeutic agent against the deleterious effects of cardiac hypertrophy after further evaluation.

ROLE OF CALCINEURIN IN ANGIOTENSIN II- INDUCED CARDIAC MYOCYTE HYPERTROPHY OF RATS

The present study investigated the role of calcineurin in angiotensin II(AngII)- induced cardiac myocyte hypertrophy of rats. Method. The primary cardiac myocytes were cultured under the standard conditions. The calcineurin activity in AngII- treated cardiomyocytes was tested by using PNPP;protein synethsis rate was assessed by 3H- leucine incorporation; atrial natriuretic factor(ANF) mRNA level was determined by Northern blot analysis. Cell viability was estimated by lactate dehydrogenase(LDH) levels in cultured medium and by dyed cell numbers. Result. After stimulation of 10,100 and 1 000nmol/L of AngII, calcineurin activities in the cardiomyocytes were increased by 13％ ,57％ (P Conclusion. During AngII- induced cardiac myocyte hypertrophy, calcineurin signal pathway is activated, and inhibition of the pathway can attenuate AngII- induced cardiac myocyte hypertrophy, which suggests that the calcineurin signal pathway may play an important role in AngII- induced myocardial hypertrophy of rats.

Molecular mechanism of carvedilol on attenuating the reversion back towards fetal energy metabolism during the development of cardiac hypertrophy

Objective to explore the molecular mechanism of carvedilol effect on fetal energy metabolism during the development of cardiac hypertrophy. Methods Male Wistar rats were divided into the coarctation of abdominal aorta group (CAA), sham operation group (SH), and carvedilol intervention group (CAR+CAA, carvedilol 30mg·kg -1 ·day -1 orally) and carvedilol control group (CAR+SH). Hemodynamics, ventricular remodeling parameters, free fatty acid in blood serum and cardiac myocyte, RT PCR analysis of the expressions of Muscle Carnitine Palmitoyltransferase I (M CPT I) and Medium Chain Acyl CoA Dehydrogenase (MCAD) mRNA were measured in all rats at 16 week after operation. Results Left ventricular hypertrophy occurrd after operation 16 weeks in group of CAA, accompanying with plasma free fatty acids accumulation, and both the levels of M CPT I and MCADmRNA were decreased significantly ( P <0.05). Carvedilol can reduce the left ventricular hypertrophy induced by pressure overload. The gene expressions of rate limiting enzyme(M CPT I) and key enzyme of fatty acid (MCAD) were upregulated in the CAR+CAA group, comparing with CAA group ( P <0.05). There was no statistically significant difference between SH group and CAR + SH group. Pressure overload in CAA rats downregulates the gene expression of rate limiting enzyme and key enzyme of fatty acid oxidation. Conclusions The intervention with carvedilol may attenuates the reversion of the metabolic gene expression back towards fetal type through up regulating the expression of M CPT I and MCADmRNA. Thus, carvedilol may confer cardioprotective effects in heart failure partly by preserving of the normal metabolic gene regulation.

Protective effect of sodium ferulate on cardiac hypertrophy in spontaneously hypertensive rats

OBJECTIVE To investigate the inhibitory effect and mechanism of sodium ferulate(SF)on myocardial hypertrophy in spontaneously hypertensive(SHR).METHODS Forty 14-week-old SHR male rats were randomly divided into model group(SHR,receive distilled water)and SF treatment groups(SF 20,40 and 80 mg·kg^-1 per day,respectively).Age-matched male Wistar-Kyoto(WKY)rats gavaged with distilled water served as controls.After 12 weeks of treatment,the effects of SF on cardiac hypertrophy were evaluated using echocardiographic measurement,pathological analysis and the expression of atrial natriuretic peptide(ANP),myosin heavy chainβ(β-MHC)-a gene related to myocardial hypertrophy.In order to explore the mechanism of SF on myocardial hypertrophy,the calcium-sensing receptor(CaSR),calcineurin(CaN),nuclear factor of activated T cell 3(NFAT3),phosphorylation NFAT3(p-NFAT3),zinc finger transcription factor(GATA4),phosphorylation GATA4(p-GATA4),protein kinase Cβ(PKC-β),Raf-1,extracellular regulated protein kinase 1/2(ERK 1/2),phosphorylation ERK1/2(p-ERK 1/2)and mitogen-activated protein kinase phosphatase-1(MKP-1)were detected.RESULTS The myocardial hypertrophy parameters,myocardial cell cross section area,left ventricular wall thickness and expression of ANP and β-MHC,CaSR,CaN,NFAT3,p-GATA4,PKC-β,Raf-1,and p-ERK 1/2 were significantly increased,while the left ventricular cavity was significantly smaller,expression of p-NFAT3 and MKP-1 were significantly decreased,meanwhile,the ultra⁃structure of cardiomyocytes was significantly damaged in 26-week-old SHR rats.Notably,SF significantly ameliorated myocardial hyper⁃trophy in 26-week-old SHR rats;suppressed the overexpression of ANP,β-MHC,CaSR,CaN,NFAT3,p-GATA4,PKC-β,Raf-1,and p-ERK 1/2 and increased the expression of p-NFAT3 and MKP-1.CONCLUSION SF can inhibit cardiac hypertrophy in SHR rats,and the mechanism may be related to the inhibition of CaSR mediated signaling pathway.

Familial Atrial Enlargement,Conduction Disorder and Symmetric Cardiac Hypertrophy Are Early Signs of PRKAG2 R302Q

PRKAG2 cardiac syndrome(PS)is a rare inherited disease due to PRKAG2 gene mutation and characterized by Wolff-Parkinson-White syndrome(WPWs),conduction system lesions and myocardial hypertrophy.It can also lead to serious consequences,such as sudden death.But the genetic and clinical heterogeneity makes the early diagnosis of PS difficult.Here we studied a family with familial hypertrophic cardiomyopathy and other diverse manifestations.Gene analysis identified a missense mutation(Arg302Gln)in the five affected subjects of the family.The electrocardiograph performance of the five was composed of sinus bradycardia(SB),WPWs,right bundle branch block(RBBB),atrioventricular block(AVB),left bundle branch block(LBBB),supraventricular tachycardia(SVT)and atrial premature beat(APB).Among them,the youngest one began to show paroxysmal palpitation at the age of nine and was confirmed to have WPWs at 17 years old;two members progressed over time to serious conduction damage,and the proband received a pacemaker at the age of 27 due to AVB.Besides,according to cardiac magnetic resonance and echocardiography,the youngest one showed symmetric hypertrophy;three older members showed asymmetric myocardial hypertrophy characterized with a diffuse pattern of middle-anterior-lateral-inferior wall hypertrophy and especially interventricular septal hypertrophy;all five affected patients showed atrial enlargement regardless of myocardial hypertrophy at an earlier stage.In conclusion,the conduction system disorder,familial atrial enlargement and symmetric cardiac hypertrophy may occur in the early stage of PRKAG2 R302Q mutation.

Reversing Effects of DDPH on Cardiac Hypertrophy andIncreased Collagen Content Induced by Partial Narrowing of Abdominal Aorta

To investigate the reversing effects of DDPH on cardiac hypertrophy and increased collagen content in left ventricle tissue of rats, cardiac hypertrophy of rats were induced by partial narrowing of abdominal aorta. 4 weeks after operation, the rats were given DDPH for 8 weeks. 12 weeks later, it was found that in model group, LVW/WHW and WHW/BW increased by 39. 0 % and 36. 9 % than those in control group; collagen content increased by 1. 5 times. I/E, LS decreased (P<0. 01), MMW/E. WZ increased (P<0. 01). The above-mentioned changes in two DDPH groups could be partly or completely reversed. It is concluded that DDPH could reverse cardiac hypertrophy of rats induced by partial narrowing of abdominal aorta and reduce collagen content in left ventricle tissue.

Protective effect of astragaloside IV on cardiac hypertrophy in rats and its mechanism

Objective:To investigate the effect of astragaloside IV on cardiac hypertrophy and its regulation on autophagy.Methods:Fifty male Sprague-Dawley rats were randomly divided into sham operation group and abdominal aortic coarctation group(AAC group).There were 10 rats in sham operation group and 40 rats in the AAC group.One week after the operation,there were 32 rats in AAC group,10 rats in sham group.AAC group was randomly divided into model group,low-dose astragaloside group,high-dose astragaloside group and rapamycin group,8 rats in each group.Rapamycin group was a positive autophagy contrast agent group.They were given the corresponding solvents once a day by gavage for six weeks.At the end of study,three rats were randomly selected from each group,left ventricular mass index(LVW/BW),cardiac mass index(HW/BW)and the content of hydroxyproline were measured.HE staining,masson staining and sirius red staining were used to observe the morphological changes of myocardium.The expression of LC3II,LC3I,Beclin1,AMPK and mTOR were detected by western blot.Results:Compared with the sham operation group,AAC group showed hypertrophy,LVW/BW,HW/BW,HYP and p-mTOR/mTOR were significantly increased(P<0.05),p-AMPK/AMPK,LC3II/LC3I,Beclin1 were significantly decreased(P<0.05).Compared with the model group,the low-dose astragaloside IV group showed the hypertrophy of cardiomyocytes was relatively light,LVW/BW and HW/BW were significantly decreased(P<0.05),there was no significant difference in HYP and p-mTOR/mTOR(P>0.05),LC3II/LC3I,Beclin1 and p-AMPK/AMPK were significantly increased(P<0.05).Compared with the model group,high-dose astragaloside IV group and rapamycin group showed reduced myocardial hypertrophy,LVW/BW,HW/BW,HYP and p-mTOR/mTOR were significantly decreased(P<0.05),LC3II/LC3I,Beclin1 and p-AMPK/AMPK were significantly increased(P<0.05).Compared with the low-dose astragaloside group,the high-dose astragaloside group showed reduced myocardial hypertrophy,there were significant differences in each index(P<0.05).Compared with rapamycin group,there was no obvious difference in morphology and structure of myocardial cells,LVW/BW,HYP and p-mTOR/mTOR were decreased(P<0.05),HW/BW and p-AMPK/AMPK had no significant difference(P>0.05),LC3II/LC3I and Beclin1 were increased in high-dose astragaloside group(P<0.05).Conclusion:As IV has protective effect on cardiac hypertrophy in a dose-dependent manner and its mechanism may be related to regulate autophagy.

VARIATION AND SIGNIFICANCE OF C-MYC PROTEIN IN RAT CARDIAC VOLUME-OVERLOAD HYPERTROPHY

Objective To investigate the change of c-myc protein, which was chosen as the response indicator to volume-overload. Methods The time and spatial course of c-myc protein expression on the model of rat cardiac volume-overload hypertrophy was examined by immunohistochemical study. Results The immunohistochemical study indicated the expression of c-myc protein was increased obviously at 4-6 hours (62.73%) than that of control (45.41%, P<0.01) after the volume-overload, then decreased gradually along with development of volume-overload hypertrophy and was decreased extremely at 5 months(r=-0.514,P<0.01).Conclusion There are disorders in the signal transduction pathways governing the hypertrophic response of cardiomyocytes in hypertrophic myocardium. C-myc gene and the product of it may be only the promoter gene of myocardial hypertrophy. Once switching on,c-myc gene and the product of it do not act anymore;While it may be that c-myc gene and the product of it increased following with myocardial hypertrophy, and have not direct relation to the occurrence and development of myocardial hypertrophy.

MiR-16 regulates CCND1 and CCND2 expression contributing to cardiac hypertrophy

MicroRNAs(miRNAs) are a class of endogenous small noncoding RNAs that regulate gene expression post-transcriptionally. Recent studies have demonstrated that miRNAs are involved in the pathogenesis of hypertrophy.We investigated miR-16 expression and their potential roles in a rat model of hypertrophy induced by abdominal artery constriction (AAC).miR-16 expression was significantly decreased, and CCND1 and CCND2 protein were markedly increased without obvious change of its mRNA level after hypertrophy induction.CCND1 and CCND2 levels were increased without changing their transcript levels in neonatal rat ventricular cardiomyocytes(NRVC) induced by PE,and miR-16 was down-regulated in this process with significantly up-regulatedβ-MHC,ANF and MLC-2 expression.Conversely,introduction of functional miR-16,CCND1 siRNA or CCND2 siRNA into NRVCs could repress cardiomyocyte hypertrophy.These results implicate that miR-16 is involved in contributing to cardiac hypertrophy,one of the mechanisms may be resulted from post-transcriptional regulation of CCND1 and CCND2.

Signaling Pathways Involved in Cardiac Hypertrophy

Cardiac hypertrophy is the heart＇s response to a variety of extrinsic and intrinsic stimuli that impose increased biomechanical stress. Traditionally, it has been considered a beneficial mechanism; however, sustained hypertrophy has been associated with a significant increase in the risk of cardiovascular disease and mortality. Delineating intracellular signaling pathways involved in the different aspects of cardiac hypertrophy will permit future improvements in potential targets for therapeutic intervention. Generally, there are two types of cardiac hypertrophies, adaptive hypertrophy, including eutrophy （normal growth） and physiological hypertrophy （growth induced by conditioning）, and maladaptive hypertrophy, physical including pathologic or reactive hypertrophy （growth induced by pathologic stimuli） and hypertrophic growth caused by genetic mutations affecting sarcomeric or cytoskeletal proteins. Accumulating observations from animal models and human patients have identified a number of intracellular signaling pathways that characterized as important transducers of the hypertrophic response, including calcineurin/nuclear factor of activated Tcells, phosphoinositide 3-kinases/Akt （PI3Ks/Akt）, G protein-coupled receptors, small G proteins, MAPK, PKCs, Gp130/STAT3, Na＋/H＋ exchanger, peroxisome proliferator-activated receptors, myocyte enhancer factor 2/histone deacetylases, and many others. Furthermore, recent evidence suggests that adaptive cardiac hypertrophy is regulated in large part by the growth hormone/insulin-like growth factors axis via signaling through the PI3K/Akt pathway. In contrast, pathological or reactive hypertrophy is triggered by autocrine and paracrine neurohormonal factors released during biomechanical stress that signal through the Gq/phosphorlipase C pathway, leading to an increase in cytosolic calcium and activation of PKC.

Cardioprotective Potential of Cymbopogon citratus Essential Oil against Isoproterenol-induced Cardiomyocyte Hypertrophy:Possible Involvement of NLRP3 Inflammasome and Oxidative Phosphorylation Complex Subunits

Objective:Cymbopogon citratus(DC.)Stapf is a medicinal and edible herb that is widely used for the treatment of gastric,nervous and hypertensive disorders.In this study,we investigated the cardioprotective effects and mechanisms of the essential oil,the main active ingredient of Cymbopogon citratus,on isoproterenol(ISO)-induced cardiomyocyte hypertrophy.Methods:The compositions of Cymbopogon citratus essential oil(CCEO)were determined by gas chromatography-mass spectrometry.Cardiomyocytes were pretreated with 16.9µg/L CCEO for 1 h followed by 10µmol/L ISO for 24 h.Cardiac hypertrophy-related indicators and NLRP3 inflammasome expression were evaluated.Subsequently,transcriptome sequencing(RNA-seq)and target verification were used to further explore the underlying mechanism.Results:Our results showed that the CCEO mainly included citronellal(45.66%),geraniol(23.32%),and citronellol(10.37%).CCEO inhibited ISO-induced increases in cell surface area and protein content,as well as the upregulation of fetal gene expression.Moreover,CCEO inhibited ISO-induced NLRP3 inflammasome expression,as evidenced by decreased lactate dehydrogenase content and downregulated mRNA levels of NLRP3,ASC,CASP1,GSDMD,and IL-1β,as well as reduced protein levels of NLRP3,ASC,pro-caspase-1,caspase-1(p20),GSDMD-FL,GSDMD-N,and pro-IL-1β.The RNA-seq results showed that CCEO inhibited the increase in the mRNA levels of 26 oxidative phosphorylation complex subunits in ISO-treated cardiomyocytes.Our further experiments confirmed that CCEO suppressed ISO-induced upregulation of mt-Nd1,Sdhd,mt-Cytb,Uqcrq,and mt-Atp6 but had no obvious effects on mt-Col expression.Conclusion:CCEO inhibits ISO-induced cardiomyocyte hypertrophy through the suppression of NLRP3 inflammasome expression and the regulation of several oxidative phosphorylation complex subunits.

Lymphangiogenesis contributes to exercise-induced physiological cardiac growth

Background:Promoting cardiac lymphangiogenesis exerts beneficial effects for the heart.Exercise can induce physiological cardiac growth with cardiomyocyte hypertrophy and increased proliferation markers in cardiomyocytes.However,it remains unclear whether and how lymphangiogenesis contributes to exercise-induced physiological cardiac growth.We aimed to investigate the role and mechanism of lymphangiogenesis in exercise-induced physiological cardiac growth.Methods:Adult C57 BL6/J mice were subjected to 3 weeks of swimming exercise to induce physiological cardiac growth.Oral treatment with vascular endothelial growth factor receptor 3(VEGFR3) inhibitor SAR1 3 1 675 was used to investigate whether cardiac lymphangiogenesis was required for exercise-induced physiological cardiac growth by VEGFR3 activation.Furthermore,human dermal lymphatic endothelial cell(LEC)-conditioned medium was collected to culture isolated neonatal rat cardiomyocytes to determine whether and how LECs could influence cardiomyocyte proliferation and hypertrophy.Results:Swimming exercise induced physiological cardiac growth accompanied by a remarkable increase of cardiac lymphangiogenesis as evidenced by increased density of lymphatic vessel endothelial hyaluronic acid receptor 1-positive lymphatic vessels in the heart and upregulated LYVE-1 and Podoplanin expressions levels.VEGFR3 was upregulated in the exercised heart,while VEGFR3 inhibitor SAR131675 attenuated exercise-induced physiological cardiac growth as evidenced by blunted myocardial hypertrophy and reduced proliferation marker Ki67 in cardiomyocytes,which was correlated with reduced lymphatic vessel density and downregulated LYVE-1 and Podoplanin in the heart upon exercise.Furthermore,LEC-conditioned medium promoted both hypertrophy and proliferation of cardiomyocytes and contained higher levels of insulinlike growth factor-1 and the extracellular protein Reelin,while LEC-conditioned medium from LECs treated with SAR131675 blocked these effects.Functional rescue assays further demonstrated that protein kinase B(AKT) activation,as well as reduced CCAAT enhancer-binding protein beta(C/EBPβ) and increased CBP/p300-interacting transactivators with E(glutamic acid)/D(aspartic acid)-rich-carboxylterminal domain 4(CITED4),contributed to the promotive effect of LEC-conditioned medium on cardiomyocyte hypertrophy and proliferation.Conclusion:Our findings reveal that cardiac lymphangiogenesis is required for exercise-induced physiological cardiac growth by VEGFR3 activation,and they indicate that LEC-conditioned medium promotes both physiological hypertrophy and proliferation of cardiomyocytes through AKT activation and the C/EBPβ-CITED4 axis.These results highlight the essential roles of cardiac lymphangiogenesis in exercise-induced physiological cardiac growth.

Total Glycosides of Ranunculus Japonius Prevent Hypertrophy in Cardiomyocytes via Alleviating Chronic Ca^(2+) Overload

Objective To evaluate the in vitro anti-hypertrophic effect of total Glycosides of Ranunculus Japonius （TGRJ）. Methods Neonatal rat cardiomyocytes were cultured and hypertrophy was induced by adminis- trating isoproterenol （ISO, 10 gmol/L） or angiotensin Ⅱ （AngⅡ, 1 gmol/L） for 48 hours. In the treatment groups, cells were pretreated with TGRJ （0.3 g/L） for 30 minutes prior to hypertrophic stimuli. The anti-hypertrophic effects of TGRJ were examined by measuring cell size, total protein content, and protein synthesis. Intracellular free Ca2＋ concentration （[Ca2＋]i） was evaluated using fluorescence dye Fura-2/AM. Sacroplasmic/endoplasmic reticulum Ca2＋ ATPase 2a （SERCA2a）, atrial natriuretic peptide （ANP）, B-type natriuretic peptide （BNP）, and beta-myosin heavy chain （β-MHC） protein expression levels were measured by Western blotting. SERCA2a activity was assayed by p-nitrophenal phosphate disodium salt hexahydrate method. Results Increased cell size, total protein content, and protein synthesis following ISO or Ang II stimulation were significantly inhibited by pretreatment with TGRJ （all P〈0.05）. This anti-hypertrophic effect of TGRJ was confirmed by its suppressing effect on elevated expression of the three hypertrophic related genetic markers, ANP, BNP, and ^-MHC. In addition, TGRJ inhibited ISO or Ang Ⅱ induced up-regulation of [Ca2＋] under chronic but not acute conditions. And ISO or Ang Ⅱ induced down-regulation of SERCA2a expression and activity was also effectively rectified byTGRJ pretreatment. Conclusions The results of present study suggested that TGRJ could prevent ISO or Ang Ⅱ induced cardiac hypertrophy through improving chronic [Ca2＋]i disorder, might via normalizing SERCA2a expression and activity.

Free fatty acid receptor 2 promotes cardiomyocyte hypertrophy by activating STAT3 and GATA4

Free fatty acids(FFAs)play important roles in cardiovascular disease.Studies have shown that it is an important way for FAs to exert biological effects through their own receptors besides directly participating biochemical reaction in body.Free fatty acid receptor 2(FFA2)can be activated by short-chain FAs and is involved in inflammatory reactions and lipid accumulation.Since the known pathological changes caused by FFA2 are also implicated in cardiac hypertrophy,we hypothesized that FFA2 might be pathogenic in cardiac hypertrophy.This paper showed that FFA2 expression significantly increased in cardiac hypertrophy in vivo and in vitro.FFA2 agonist 4-CMTB or TUG-1375 promoted the expression of the hypertrophy markers ANF and BNP and increased cell surface area in vitro,which was further strengthened by FFA2 overexpression,suggesting that FFA2 might contribute to cardiomyocyte hypertrophy.Furthermore,4-CMTB treatment or FFA2 overexpression combined with 4-CMTB treatment elevated the phosphorylation and transcriptional activity of GATA4 and STAT3,which were inhibited by an ERK1/2 inhibitor,and GATA4 and STAT3 knockdown inhibited the elevation of hypertrophy biomarkers in cardiomyocytes treated with 4-CMTB.Taken together,these data indicate that FFA2 can enhance cardiomyocyte hypertrophy by activating STAT3 and GATA4 via ERK1/2,providing a potential new target for therapy.

Canagliflozin attenuates hypertension induced myocardial hypertrophy and fibrosis via RAS and TGF-β1/Smad pathway

Objective:To investigate the effects of cagliazin,a sodium-glucose cotransporter 2 inhibitor(SGLT-2I),on ventricular remodeling in spontaneously hypertensive rats(SHR)through renin angiotensin system(RAS)and transforming growth factor-β1(TGF-β1).Methods:The experiment was divided into 4 groups:normal blood pressure control group,SHR group,cagliet net low-dose group(30mg/kg),cagliet net high-dose group(60mg/kg),once a day for 8 weeks.Normal blood pressure rats(WKY)were used as the control group to measure blood pressure with tail sleeve sphygmomanometer(BP)and blood glucose level was measured with glucose meter Cardiac function was evaluated by echocardiography,cell area of left ventricle was evaluated by histomorphology,real-time quantitative polymerase chain reaction and protein imprinting hybridization were used to detect TGF-β1 Smad4 renin from type I collagen(Col1a)type III collagen(Col3a)matrix metalloproteinase 2(MMP-2)Expression results of angiotensin II1 type receptor 1(AGTR1)and Angiotensin II2 type receptor 2(AGTR2).Results:After 8 weeks of administration,the cardiac weight/body weight ratio(HW/BW)of left ventricular weight/heart weight ratio(LVW/HW)of kaglinet low-dose group and high-dose group was statistically significant compared with that of spontaneous hypertensive rats(P&lt);Compared with SHRs,the expression of Col1a,Col3a,MMP2,TGF-β1,Smad4,Renin AGTR1 was significantly down-regulated and the expression of AGTR2 was up-regulated in cagliet net low-dose and high-dose groups Conclusions:Cagliazin can improve hypertension-induced cardiac remodeling by regulating RAS and TGF-β1/Smad signaling pathways.Conclusion:From the results,canaglifozin was found to ameliorate pressure overload-induced cardiac remodeling by regulating the RAS and TGF-β1/Smad signaling pathway.

lncRNA ZNF593-AS inhibits cardiac hypertrophy and myocardial remodeling by upregulating Mfn2 expression

lncRNA ZNF593 antisense(ZNF593-AS)transcripts have been implicated in heart failure through the regulation of myocardial contractility.The decreased transcriptional activity of ZNF593-AS has also been detected in cardiac hypertrophy.However,the function of ZNF593-AS in cardiac hypertrophy remains unclear.Herein,we report that the expression of ZNF593-AS reduced in a mouse model of left ventricular hypertrophy and cardiomyocytes in response to treatment with the hypertrophic agonist phenylephrine(PE).In vivo,ZNF593-AS aggravated pressure overload–induced cardiac hypertrophy in knockout mice.By contrast,cardiomyocyte-specific transgenic mice(ZNF593-AS MHC-Tg)exhibited attenuated TAC-induced cardiac hypertrophy.In vitro,vector-based overexpression using murine or human ZNF593-AS alleviated PE-induced myocyte hypertrophy,whereas GapmeR-induced inhibition aggravated hypertrophic phenotypes.By using RNA-seq and gene set enrichment analyses,we identified a link between ZNF593-AS and oxidative phosphorylation and found that mitofusin 2(Mfn2)is a direct target of ZNF593-AS.ZNF593-AS exerts an antihypertrophic effect by upregulating Mfn2 expression and improving mitochondrial function.Therefore,it represents a promising therapeutic target for combating pathological cardiac remodeling.

lncRNA Gm20257 alleviates pathological cardiac hypertrophy by modulating the PGC-1α–mitochondrial complexⅣaxis

Pathological cardiac hypertrophy,a major contributor to heart failure,is closely linked to mitochondrial function.The roles of long noncoding RNAs(lncRNAs),which regulate mitochondrial function,remain largely unexplored in this context.Herein,a previously unknown lncRNA,Gm20257,was identified.It markedly increased under hypertrophic stress in vivo and in vitro.The suppression of Gm20257 by using small interfering RNAs significantly induced cardiomyocyte hypertrophy.Conversely,the overexpression of Gm20257 through plasmid transfection or adeno-associated viral vector-9 mitigated angiotensinⅡ-induced hypertrophic phenotypes in neonatal mouse ventricular cells or alleviated cardiac hypertrophy in a mouse TAC model respectively,thus restoring cardiac function.Importantly,Gm20257 restored mitochondrial complexⅣlevel and enhanced mitochondrial function.Bioinformatics prediction showed that Gm20257 had a high binding score with peroxisome proliferator–activated receptor coactivator-1(PGC-1α),which could increase mitochondrial complex IV.Subsequently,Western blot analysis results revealed that Gm20257 substantially affected the expression of PGC-1α.Further analyses through RNA immunoprecipitation and immunoblotting following RNA pull-down indicated that PGC-1αwas a direct downstream target of Gm20257.This interaction was demonstrated to rescue the reduction of mitochondrial complex IV induced by hypertrophic stress and promote the generation of mitochondrial ATP.These findings suggest that Gm20257 improves mitochondrial function through the PGC-1α-mitochondrial complexⅣaxis,offering a novel approach for attenuating pathological cardiac hypertrophy.