Background:Exercise is beneficial for muscle atrophy.Peroxisome proliferator-activated receptor gamma(PPARγ) and microRNA-29 b(miR-29 b) have been reported to be responsible for angiotensinⅡ(AngⅡ)-induced muscle at...Background:Exercise is beneficial for muscle atrophy.Peroxisome proliferator-activated receptor gamma(PPARγ) and microRNA-29 b(miR-29 b) have been reported to be responsible for angiotensinⅡ(AngⅡ)-induced muscle atrophy.However,it is unclear whether exercise can protect AngⅡ-induced muscle atrophy by targeting PPARγ/miR-29 b.Methods:Skeletal muscle atrophy in both the control group and the run group was established by AngⅡ infusion;after 1 week of exercise training,the mice were sacrificed,and muscle weight was determined.Myofiber size was measured by hematoxylin-eosin and wheat-germ agglutinin staining.Apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling staining.The expression level of muscle atrogenes,including F-box only protein 32(FBXO32,also called Atrogin-1) and muscle-specific RING-finger 1(MuRF-1),the phosphorylation level of protein kinase B(PKB,also called AKT)/forkhead box 03 A(FOX03 A)/mammalian target of rapamycin(mTOR) pathway proteins,the expression level of PPARγ and apoptosis-related proteins,including B-cell lymphoma-2(Bcl-2),Bcl-2-associated X(Bax),cysteine-aspartic acid protease 3(caspase-3),and cleaved-caspase-3,were determined by western blot.The expression level of miR-29 b was checked by reversetranscription quantitative polymerase chain reaction.A PPARγ inhibitor(T0070907) or adeno-associated virus serotype-8(AAV8)-mediated miR-29 b overexpression was used to demonstrate whether PPARγ activation or miR-29 b inhibition mediates the beneficial effects of exercise in AngⅡ-induced muscle atrophy.Results:Exercise can significantly attenuate AngⅡ-induced muscle atrophy,which is demonstrated by increased skeletal muscle weight,cross-sectional area of myofiber,and activation of AKT/mTOR signaling and by decreased atrogenes expressions and apoptosis.In AngⅡ-induced muscle atrophy mice models,PPARγ was elevated whereas miR-29 b was decreased by exercise.The protective effects of exercise in AngⅡ-induced muscle atrophy were inhibited by a PPARγ inhibitor(T0070907) or adeno-associated virus serotype-8(AAV8)-mediated miR-29 b overexpression.Conclusion:Exercise attenuates AngⅡ-induced muscle atrophy by activation of PPARγ and suppression of miR-29 b.展开更多
AIM To study hepatic vasoconstriction and glucose release induced by angiotensin(Ang)Ⅱ or Epi in rats with pharmacological hypertension and spontaneously hypertensive rat(SHR).METHODS Isolated liver perfusion was per...AIM To study hepatic vasoconstriction and glucose release induced by angiotensin(Ang)Ⅱ or Epi in rats with pharmacological hypertension and spontaneously hypertensive rat(SHR).METHODS Isolated liver perfusion was performed following portal vein and vena cava cannulation; AngⅡ or epinephrine(Epi) was injected in bolus and portal pressure monitored; glucose release was measured in perfusate aliquots. RESULTS The portal hypertensive response(PHR) and the glucose release induced by AngⅡ of L-NAME were similar to normal rats(WIS). On the other hand, the PHR inducedby Epi in L-NAME was higher whereas the glucose release was lower compared to WIS. Despite the similar glycogen content, glucose release induced by AngⅡ was lower in SHR compared to Wistar-Kyoto rats although both PHR and glucose release induced by Epi in were similar. CONCLUSION AngⅡ and Epi responses are altered in different ways in these hypertension models. Our results suggest that inhibition of NO production seems to be involved in the hepatic effects induced by Epi but not by AngⅡ; the diminished glucose release induced by AngⅡ in SHR is not related to glycogen content.展开更多
OBJECTIVE To investigate the vasorelaxant effect of pinocembrin(5,7-dihydroxyflavanone),one of the main flavonoids in propolis,on angiotensinⅡ(AngⅡ)induced vasoconstriction and the molecular mechanism of action.METH...OBJECTIVE To investigate the vasorelaxant effect of pinocembrin(5,7-dihydroxyflavanone),one of the main flavonoids in propolis,on angiotensinⅡ(AngⅡ)induced vasoconstriction and the molecular mechanism of action.METHODS The isometric vascular tone was measured in thoracic aortic rings from SD rat,and the effects of pinocembrin on the single dose and concentration cumulative response curves of AngⅡ were recorded.The binding of pinocembrin to the angiotensin type 1 receptor(AT1R)was studied by using molecule docking analysis.Intracellular[Ca2+]([Ca2+]i)was measured with Fura2/AM in VSMCs.The phosphorylation levels of myosin light chain 2(MLC2)and myosin phosphatase target unit 1(MYPT1),and protein level of Rho kinase 1(ROCK1)in the rat aortic rings were detected by Western blotting.RESULTS Pinocembrin was observed to inhibit AngⅡ-induced vasoconstriction in rat aortic rings with either intact or denuded endothelium.In endothelium-denuded tissues,pinocembrin(pD′2 4.28±0.15)counteracted the contractions evoked by cumulative concentrations of AngⅡ.In a docking model,pinocembrin showed effective binding at the active site of AT1R.Pinocembrin was shown to inhibit both AngⅡ-induced Ca2+ release from internal stores and Ca2+ influx.Moreover,the increase in the phosphorylation of MLC2 and MYPT1,and the increased protein level of ROCK1 induced by AngⅡ was blocked by pinocembrin.CONCLUSION Pinocembrin inhibits AngⅡ-induced rat aortic ring contraction in a Ca2+-dependent and Ca2+-independent manner via blocking AT1R.展开更多
Background AngiotensinⅡ(AngⅡ) plays a critical role in the pathophysiology of cardiovascular diseases. Recently,studies have shown that Endoplasmic Reticulum (ER) stress was activated in failure hearts.This study wa...Background AngiotensinⅡ(AngⅡ) plays a critical role in the pathophysiology of cardiovascular diseases. Recently,studies have shown that Endoplasmic Reticulum (ER) stress was activated in failure hearts.This study was designed to examine whether ER stress participates in the pathologic process of AngⅡ-induced cardiomyocytes apoptosis. Methods Neonatal rat cardiomyocytes were incubated with concentrations of AngⅡ(0,1,10,100 nmol/L) for 24 hours.Confocal fluorescence microscopy with double staining of TUNEL and CHOP detected the percentage of apoptotic cells.Levels of GRP78,JNK,p-JNK,CHOP and caspase-12 were analyzed by western blot.Telmisartan(10- ~6mol/L) was used to test the effects of ATI receptor on AngⅡ- induced cell apoptosis,ER stress chaperones and signaling molecules.Results Treatment with AngⅡat 1,10, and 100 nmol/L for 24 hours stimulated GRP78,JNK,p-JNK and CHOP protein production,and increased apoptosis of myocytes.The protein expression and the number of apoptotic cells were depedent on AngⅡconcentration.About 60%of apoptotic cells were CHOP positive at 10 and 100nmol/L AngⅡtreatment,while no CHOP positive apoptotic cells were found at myocytes under physiological condition and 1 nmo/L AngⅡtreatment.Telmisartan decreased signaling molecules expression and abolished ER stress-mediated apoptosis induced by 100 nmol/L AngⅡ.Conclusions These results indicate that ER stress may be involved in the mechanisms of AngⅡ-induced cardiomyocytes apoptosis.JNK, caspase12 and CHOP all participate in the pathologic process.展开更多
Background Activation of the renin-angiotensin system and the subsequent generation of angiotensin（Ang）Ⅱis an important mediator of myocardial fibrosis,pathological hypertrophy and heart failure.Angiotensin-convert...Background Activation of the renin-angiotensin system and the subsequent generation of angiotensin（Ang）Ⅱis an important mediator of myocardial fibrosis,pathological hypertrophy and heart failure.Angiotensin-converting enzyme 2（ACE2） has recently been identified as AngⅡ-degrading enzyme capable of generating Ang（1 -7） and as a negative regulator of the renin-angiotensin system.We assessed the hypothesis that ACE2 mediates its anti-fibrotic and anti-hyper-trophic effects through the modulation of AngⅡsignaling. Methods We implanted mini-osmotic pumps with AngⅡ(1.5 mg·kg<sup>-1</sup>·d<sup>-1</sup>) for 14 days in male wildtype（WT） mice which were then treated with recombinant human ACE2(rhACE2;2 mg·kg<sup>-1</sup>,d i.p.) or placebo.Systolic blood pressure of mouse was measured using the tail cuff method with the IITC Blood Pressure Monitoring Systems.Results Chronic AngⅡinfusion resulted in a predicted pressor response（peak SBP:163±7 mm Hg,n=8,P【0.01）,treatment with rhACE2 reduced the pressor response（139±4 mm Hg;n=6,P【0.05）and reduced the hypertrophic response based on left ventricular mass and expressions of atrial natriuretic factor,brain natriuretic peptide andα-skeletal actin（P【0.05,respectively）.Interestingly,echocardiographic assessment including tissue Doppler measurement revealed attenuated ventricular hypertrophy and improvement in diastolic dysfunction in AngⅡ-treated mice injected with rhACE2.Trichrome and picrosirius red staining showed a marked increase in myocardial fibrosis in response to AngⅡwhich was suppressed by rhACE2（collagen volume fraction; 7.3%±1.3%vs.4.1%±1.1%;n=6～7,P【0.05） with reduced expression of collagenⅠandⅢ,fibronectin and transforming growth factor-P in response to rhACE2.In male ACE2 knockout mice（Ace2-/y）,AngⅡinfusion resulted in greater pressor response（186±8 mm Hg;re=8,P【0.01） and worsening diastolic dysfunction compared to WT mice infused with AngⅡ.Conclusions In the setting of elevated AngⅡ,loss of ACE2 increases AngⅡ-induced hypertension and diastolic dysfunction. In contrast,recombinant human ACE2 prevents AngⅡ-mediated hypertension,myocardial hypertrophy and fibrosis.We conclude that ACE2 plays a pivotal role in the prevention of hypertension,myocardial hypertrophy and fibrosis acting as a protective mechanism in the heart to limit the pathological effects of an activated systemic and/or local RAS and ACE2 represents a novel therapeutic strategy for cardiovascular disorders.展开更多
基金supported by grants from the National Key Research and Development Project(2020YFA0803800 to JL,2018YFE0113500 to JX)National Natural Science Foundation of China(82020108002 and 81911540486 to JX)+2 种基金Innovation Program of Shanghai Municipal Education Commission(2017-01-07-00-09-E00042 to JX)Science and Technology Commission of Shanghai Municipality(20DZ2255400 and 18410722200 to JX)the“Dawn”Program of the Shanghai Education Commission(19SG34 to JX).
文摘Background:Exercise is beneficial for muscle atrophy.Peroxisome proliferator-activated receptor gamma(PPARγ) and microRNA-29 b(miR-29 b) have been reported to be responsible for angiotensinⅡ(AngⅡ)-induced muscle atrophy.However,it is unclear whether exercise can protect AngⅡ-induced muscle atrophy by targeting PPARγ/miR-29 b.Methods:Skeletal muscle atrophy in both the control group and the run group was established by AngⅡ infusion;after 1 week of exercise training,the mice were sacrificed,and muscle weight was determined.Myofiber size was measured by hematoxylin-eosin and wheat-germ agglutinin staining.Apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling staining.The expression level of muscle atrogenes,including F-box only protein 32(FBXO32,also called Atrogin-1) and muscle-specific RING-finger 1(MuRF-1),the phosphorylation level of protein kinase B(PKB,also called AKT)/forkhead box 03 A(FOX03 A)/mammalian target of rapamycin(mTOR) pathway proteins,the expression level of PPARγ and apoptosis-related proteins,including B-cell lymphoma-2(Bcl-2),Bcl-2-associated X(Bax),cysteine-aspartic acid protease 3(caspase-3),and cleaved-caspase-3,were determined by western blot.The expression level of miR-29 b was checked by reversetranscription quantitative polymerase chain reaction.A PPARγ inhibitor(T0070907) or adeno-associated virus serotype-8(AAV8)-mediated miR-29 b overexpression was used to demonstrate whether PPARγ activation or miR-29 b inhibition mediates the beneficial effects of exercise in AngⅡ-induced muscle atrophy.Results:Exercise can significantly attenuate AngⅡ-induced muscle atrophy,which is demonstrated by increased skeletal muscle weight,cross-sectional area of myofiber,and activation of AKT/mTOR signaling and by decreased atrogenes expressions and apoptosis.In AngⅡ-induced muscle atrophy mice models,PPARγ was elevated whereas miR-29 b was decreased by exercise.The protective effects of exercise in AngⅡ-induced muscle atrophy were inhibited by a PPARγ inhibitor(T0070907) or adeno-associated virus serotype-8(AAV8)-mediated miR-29 b overexpression.Conclusion:Exercise attenuates AngⅡ-induced muscle atrophy by activation of PPARγ and suppression of miR-29 b.
基金Supported by Fundacao de Amparo a Pesquisa do Estado de Sao Paulo,No.FAPESP,2011/13974-8Coordenacao de Aperfeicoamento de Pessoal de Nível Superior(CAPES)
文摘AIM To study hepatic vasoconstriction and glucose release induced by angiotensin(Ang)Ⅱ or Epi in rats with pharmacological hypertension and spontaneously hypertensive rat(SHR).METHODS Isolated liver perfusion was performed following portal vein and vena cava cannulation; AngⅡ or epinephrine(Epi) was injected in bolus and portal pressure monitored; glucose release was measured in perfusate aliquots. RESULTS The portal hypertensive response(PHR) and the glucose release induced by AngⅡ of L-NAME were similar to normal rats(WIS). On the other hand, the PHR inducedby Epi in L-NAME was higher whereas the glucose release was lower compared to WIS. Despite the similar glycogen content, glucose release induced by AngⅡ was lower in SHR compared to Wistar-Kyoto rats although both PHR and glucose release induced by Epi in were similar. CONCLUSION AngⅡ and Epi responses are altered in different ways in these hypertension models. Our results suggest that inhibition of NO production seems to be involved in the hepatic effects induced by Epi but not by AngⅡ; the diminished glucose release induced by AngⅡ in SHR is not related to glycogen content.
基金The project supported by National Natural Science Foundation of China(81102444)the Major Scientific and Technological Special Project for"Significant New Drugs Creation"(2009ZX09302-003,2013ZX09508104)the Central Public Scientific Research Institution Fundamental Project(2014CX05)
文摘OBJECTIVE To investigate the vasorelaxant effect of pinocembrin(5,7-dihydroxyflavanone),one of the main flavonoids in propolis,on angiotensinⅡ(AngⅡ)induced vasoconstriction and the molecular mechanism of action.METHODS The isometric vascular tone was measured in thoracic aortic rings from SD rat,and the effects of pinocembrin on the single dose and concentration cumulative response curves of AngⅡ were recorded.The binding of pinocembrin to the angiotensin type 1 receptor(AT1R)was studied by using molecule docking analysis.Intracellular[Ca2+]([Ca2+]i)was measured with Fura2/AM in VSMCs.The phosphorylation levels of myosin light chain 2(MLC2)and myosin phosphatase target unit 1(MYPT1),and protein level of Rho kinase 1(ROCK1)in the rat aortic rings were detected by Western blotting.RESULTS Pinocembrin was observed to inhibit AngⅡ-induced vasoconstriction in rat aortic rings with either intact or denuded endothelium.In endothelium-denuded tissues,pinocembrin(pD′2 4.28±0.15)counteracted the contractions evoked by cumulative concentrations of AngⅡ.In a docking model,pinocembrin showed effective binding at the active site of AT1R.Pinocembrin was shown to inhibit both AngⅡ-induced Ca2+ release from internal stores and Ca2+ influx.Moreover,the increase in the phosphorylation of MLC2 and MYPT1,and the increased protein level of ROCK1 induced by AngⅡ was blocked by pinocembrin.CONCLUSION Pinocembrin inhibits AngⅡ-induced rat aortic ring contraction in a Ca2+-dependent and Ca2+-independent manner via blocking AT1R.
文摘Background AngiotensinⅡ(AngⅡ) plays a critical role in the pathophysiology of cardiovascular diseases. Recently,studies have shown that Endoplasmic Reticulum (ER) stress was activated in failure hearts.This study was designed to examine whether ER stress participates in the pathologic process of AngⅡ-induced cardiomyocytes apoptosis. Methods Neonatal rat cardiomyocytes were incubated with concentrations of AngⅡ(0,1,10,100 nmol/L) for 24 hours.Confocal fluorescence microscopy with double staining of TUNEL and CHOP detected the percentage of apoptotic cells.Levels of GRP78,JNK,p-JNK,CHOP and caspase-12 were analyzed by western blot.Telmisartan(10- ~6mol/L) was used to test the effects of ATI receptor on AngⅡ- induced cell apoptosis,ER stress chaperones and signaling molecules.Results Treatment with AngⅡat 1,10, and 100 nmol/L for 24 hours stimulated GRP78,JNK,p-JNK and CHOP protein production,and increased apoptosis of myocytes.The protein expression and the number of apoptotic cells were depedent on AngⅡconcentration.About 60%of apoptotic cells were CHOP positive at 10 and 100nmol/L AngⅡtreatment,while no CHOP positive apoptotic cells were found at myocytes under physiological condition and 1 nmo/L AngⅡtreatment.Telmisartan decreased signaling molecules expression and abolished ER stress-mediated apoptosis induced by 100 nmol/L AngⅡ.Conclusions These results indicate that ER stress may be involved in the mechanisms of AngⅡ-induced cardiomyocytes apoptosis.JNK, caspase12 and CHOP all participate in the pathologic process.
文摘Background Activation of the renin-angiotensin system and the subsequent generation of angiotensin（Ang）Ⅱis an important mediator of myocardial fibrosis,pathological hypertrophy and heart failure.Angiotensin-converting enzyme 2（ACE2） has recently been identified as AngⅡ-degrading enzyme capable of generating Ang（1 -7） and as a negative regulator of the renin-angiotensin system.We assessed the hypothesis that ACE2 mediates its anti-fibrotic and anti-hyper-trophic effects through the modulation of AngⅡsignaling. Methods We implanted mini-osmotic pumps with AngⅡ(1.5 mg·kg<sup>-1</sup>·d<sup>-1</sup>) for 14 days in male wildtype（WT） mice which were then treated with recombinant human ACE2(rhACE2;2 mg·kg<sup>-1</sup>,d i.p.) or placebo.Systolic blood pressure of mouse was measured using the tail cuff method with the IITC Blood Pressure Monitoring Systems.Results Chronic AngⅡinfusion resulted in a predicted pressor response（peak SBP:163±7 mm Hg,n=8,P【0.01）,treatment with rhACE2 reduced the pressor response（139±4 mm Hg;n=6,P【0.05）and reduced the hypertrophic response based on left ventricular mass and expressions of atrial natriuretic factor,brain natriuretic peptide andα-skeletal actin（P【0.05,respectively）.Interestingly,echocardiographic assessment including tissue Doppler measurement revealed attenuated ventricular hypertrophy and improvement in diastolic dysfunction in AngⅡ-treated mice injected with rhACE2.Trichrome and picrosirius red staining showed a marked increase in myocardial fibrosis in response to AngⅡwhich was suppressed by rhACE2（collagen volume fraction; 7.3%±1.3%vs.4.1%±1.1%;n=6～7,P【0.05） with reduced expression of collagenⅠandⅢ,fibronectin and transforming growth factor-P in response to rhACE2.In male ACE2 knockout mice（Ace2-/y）,AngⅡinfusion resulted in greater pressor response（186±8 mm Hg;re=8,P【0.01） and worsening diastolic dysfunction compared to WT mice infused with AngⅡ.Conclusions In the setting of elevated AngⅡ,loss of ACE2 increases AngⅡ-induced hypertension and diastolic dysfunction. In contrast,recombinant human ACE2 prevents AngⅡ-mediated hypertension,myocardial hypertrophy and fibrosis.We conclude that ACE2 plays a pivotal role in the prevention of hypertension,myocardial hypertrophy and fibrosis acting as a protective mechanism in the heart to limit the pathological effects of an activated systemic and/or local RAS and ACE2 represents a novel therapeutic strategy for cardiovascular disorders.
