Limits...
Aliskiren ameliorates pressure overload-induced heart hypertrophy and fibrosis in mice.

Weng LQ, Zhang WB, Ye Y, Yin PP, Yuan J, Wang XX, Kang L, Jiang SS, You JY, Wu J, Gong H, Ge JB, Zou YZ - Acta Pharmacol. Sin. (2014)

Bottom Line: The levels of signaling proteins were measured using Western blotting, while the expression of the relevant genes was analyzed using real-time QRT-PCR.These pathological alterations in TAC-mice were significantly ameliorated or blocked by ALK administration.In mechanically stretched cardiomyocytes, CGP53353 (a PKCβI inhibitor) prevented ERK phosphorylation and autophagic responses, while U0126 (an ERK inhibitor) blocked autophagic responses.

View Article: PubMed Central - PubMed

Affiliation: Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institute of Biomedical Science, Fudan University, Shanghai 200032, China.

ABSTRACT

Aim: Aliskiren (ALK) is a renin inhibitor that has been used in the treatment of hypertension. The aim of this study was to determine whether ALK could ameliorate pressure overload-induced heart hypertrophy and fibrosis, and to elucidate the mechanisms of action.

Methods: Transverse aortic constriction (TAC) was performed in mice to induce heart pressure overload. ALK (150 mg·kg(-1)·d(-1), po), the autophagy inhibitor 3-methyladenine (10 mg·kg(-1) per week, ip) or the PKCβI inhibitor LY333531 (1 mg·kg(-1)·d-(1), po) was administered to the mice for 4 weeks. Heart hypertrophy, fibrosis and function were evaluated based on echocardiography, histological and biochemical measurements. Mechanically stretched cardiomyocytes of rats were used for in vitro experiments. The levels of signaling proteins were measured using Western blotting, while the expression of the relevant genes was analyzed using real-time QRT-PCR.

Results: TAC induced marked heart hypertrophy and fibrosis, accompanied by high levels of Ang II in plasma and heart, and by PKCβI/α and ERK1/2 phosphorylation in heart. Meanwhile, TAC induced autophagic responses in heart, i.e. increases in autophagic structures, expression of Atg5 and Atg16 L1 mRNAs and LC3-II and Beclin-1 proteins. These pathological alterations in TAC-mice were significantly ameliorated or blocked by ALK administration. In TAC-mice, 3-methyladenine administration also ameliorated heart hypertrophy, fibrosis and dysfunction, while LY333531 administration inhibited ERK phosphorylation and autophagy in heart. In mechanically stretched cardiomyocytes, CGP53353 (a PKCβI inhibitor) prevented ERK phosphorylation and autophagic responses, while U0126 (an ERK inhibitor) blocked autophagic responses.

Conclusion: ALK ameliorates heart hypertrophy, fibrosis and dysfunction in the mouse model in setting of chronic pressure overload, via suppressing Ang II-PKCβI-ERK1/2-regulated autophagy.

Show MeSH

Related in: MedlinePlus

Effect of ALK on TAC-induced cardiac hypertrophy, fibrosis and dysfunction 4 weeks after TAC. (A) Representative M-Mode images. (B) Echocardiographic parameter analysis. LVAWd, left ventricular anterior wall thickness at end-diastole; LVIDd, left ventricular internal dimension at end-diastole; LVFS, left ventricular fractional shortening; LVEF, left ventricular ejection fraction. (C) Heart to body weight ratio (HW/BW). (D) Representative HE-stained left ventricular sections (scale bar: 20 μm) and quantitative analysis of cross-sectional area (CSA). (E) The expression of hypertrophy-associated genes. Bars indicate the relative folds of the expression of ANP, BNP, and SAA of the internal control. GAPDH served as the internal control. ANP, atrial natriuretic peptide. BNP, brain natriuretic peptide. SAA, skeletal α-actin. (F) Representative Masson's trichrome-stained left ventricular sections (scale bar: 20 μm) and fibrotic area analysis. Blue areas indicate fibrotic staining. (G) The expression of fibrosis-associated mRNA. GAPDH was used as the internal control. TGFβ1, transforming growth factor β1. Col1a1, collagen type I α1. Col3a1, collagen type III α1. n=6. Mean±SEM. bP<0.05 vs Sham. eP<0.05 vs TAC. ALK, aliskiren (150 mg·kg−1·d−1, po)
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4125714&req=5

fig1: Effect of ALK on TAC-induced cardiac hypertrophy, fibrosis and dysfunction 4 weeks after TAC. (A) Representative M-Mode images. (B) Echocardiographic parameter analysis. LVAWd, left ventricular anterior wall thickness at end-diastole; LVIDd, left ventricular internal dimension at end-diastole; LVFS, left ventricular fractional shortening; LVEF, left ventricular ejection fraction. (C) Heart to body weight ratio (HW/BW). (D) Representative HE-stained left ventricular sections (scale bar: 20 μm) and quantitative analysis of cross-sectional area (CSA). (E) The expression of hypertrophy-associated genes. Bars indicate the relative folds of the expression of ANP, BNP, and SAA of the internal control. GAPDH served as the internal control. ANP, atrial natriuretic peptide. BNP, brain natriuretic peptide. SAA, skeletal α-actin. (F) Representative Masson's trichrome-stained left ventricular sections (scale bar: 20 μm) and fibrotic area analysis. Blue areas indicate fibrotic staining. (G) The expression of fibrosis-associated mRNA. GAPDH was used as the internal control. TGFβ1, transforming growth factor β1. Col1a1, collagen type I α1. Col3a1, collagen type III α1. n=6. Mean±SEM. bP<0.05 vs Sham. eP<0.05 vs TAC. ALK, aliskiren (150 mg·kg−1·d−1, po)

Mentions: Four weeks after TAC, all experimental mice were found to have survived and subsequently received both echocardiographic and hemodynamic examinations. Both aortic blood pressure (ABP) and left ventricle end-systolic pressure (LVESP) increased by more than 1.5-fold after TAC (Figure S1). Echocardiographic results showed increased left ventricular wall thickness and impaired cardiac function in the TAC control group, compared with those in the Sham group (Figure 1A, 1B). Moreover, an augmented HW/BW, as well as an elevated CSA of cardiomyocytes, was observed (Figure 1C, 1D). Additionally, the reprogramming of ANP, BNP, and SAA was observed in the TAC group (Figure 1E). Although ALK did not elicit any notable effects on cardiac geometry and function at baseline, it evidently ameliorated all maladaptive responses induced by TAC (Figure 1), without lowering either ABP or LVESP (Figure S1). Masson's trichrome staining showed a markedly elevated interstitial collagen volume in the TAC control group as compared with that in the Sham group. However, the extracellular matrix change was significantly inhibited in the TAC-ALK group (Figure 1F). The subsequent analysis of mRNA levels of TGF-β1, Col1a1, and Col3a1 also demonstrated elevated responses in the TAC control group as compared with those in the Sham group, but each of these enhanced fibrotic markers decreased significantly in the TAC-ALK group (Figure 1G).


Aliskiren ameliorates pressure overload-induced heart hypertrophy and fibrosis in mice.

Weng LQ, Zhang WB, Ye Y, Yin PP, Yuan J, Wang XX, Kang L, Jiang SS, You JY, Wu J, Gong H, Ge JB, Zou YZ - Acta Pharmacol. Sin. (2014)

Effect of ALK on TAC-induced cardiac hypertrophy, fibrosis and dysfunction 4 weeks after TAC. (A) Representative M-Mode images. (B) Echocardiographic parameter analysis. LVAWd, left ventricular anterior wall thickness at end-diastole; LVIDd, left ventricular internal dimension at end-diastole; LVFS, left ventricular fractional shortening; LVEF, left ventricular ejection fraction. (C) Heart to body weight ratio (HW/BW). (D) Representative HE-stained left ventricular sections (scale bar: 20 μm) and quantitative analysis of cross-sectional area (CSA). (E) The expression of hypertrophy-associated genes. Bars indicate the relative folds of the expression of ANP, BNP, and SAA of the internal control. GAPDH served as the internal control. ANP, atrial natriuretic peptide. BNP, brain natriuretic peptide. SAA, skeletal α-actin. (F) Representative Masson's trichrome-stained left ventricular sections (scale bar: 20 μm) and fibrotic area analysis. Blue areas indicate fibrotic staining. (G) The expression of fibrosis-associated mRNA. GAPDH was used as the internal control. TGFβ1, transforming growth factor β1. Col1a1, collagen type I α1. Col3a1, collagen type III α1. n=6. Mean±SEM. bP<0.05 vs Sham. eP<0.05 vs TAC. ALK, aliskiren (150 mg·kg−1·d−1, po)
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4125714&req=5

fig1: Effect of ALK on TAC-induced cardiac hypertrophy, fibrosis and dysfunction 4 weeks after TAC. (A) Representative M-Mode images. (B) Echocardiographic parameter analysis. LVAWd, left ventricular anterior wall thickness at end-diastole; LVIDd, left ventricular internal dimension at end-diastole; LVFS, left ventricular fractional shortening; LVEF, left ventricular ejection fraction. (C) Heart to body weight ratio (HW/BW). (D) Representative HE-stained left ventricular sections (scale bar: 20 μm) and quantitative analysis of cross-sectional area (CSA). (E) The expression of hypertrophy-associated genes. Bars indicate the relative folds of the expression of ANP, BNP, and SAA of the internal control. GAPDH served as the internal control. ANP, atrial natriuretic peptide. BNP, brain natriuretic peptide. SAA, skeletal α-actin. (F) Representative Masson's trichrome-stained left ventricular sections (scale bar: 20 μm) and fibrotic area analysis. Blue areas indicate fibrotic staining. (G) The expression of fibrosis-associated mRNA. GAPDH was used as the internal control. TGFβ1, transforming growth factor β1. Col1a1, collagen type I α1. Col3a1, collagen type III α1. n=6. Mean±SEM. bP<0.05 vs Sham. eP<0.05 vs TAC. ALK, aliskiren (150 mg·kg−1·d−1, po)
Mentions: Four weeks after TAC, all experimental mice were found to have survived and subsequently received both echocardiographic and hemodynamic examinations. Both aortic blood pressure (ABP) and left ventricle end-systolic pressure (LVESP) increased by more than 1.5-fold after TAC (Figure S1). Echocardiographic results showed increased left ventricular wall thickness and impaired cardiac function in the TAC control group, compared with those in the Sham group (Figure 1A, 1B). Moreover, an augmented HW/BW, as well as an elevated CSA of cardiomyocytes, was observed (Figure 1C, 1D). Additionally, the reprogramming of ANP, BNP, and SAA was observed in the TAC group (Figure 1E). Although ALK did not elicit any notable effects on cardiac geometry and function at baseline, it evidently ameliorated all maladaptive responses induced by TAC (Figure 1), without lowering either ABP or LVESP (Figure S1). Masson's trichrome staining showed a markedly elevated interstitial collagen volume in the TAC control group as compared with that in the Sham group. However, the extracellular matrix change was significantly inhibited in the TAC-ALK group (Figure 1F). The subsequent analysis of mRNA levels of TGF-β1, Col1a1, and Col3a1 also demonstrated elevated responses in the TAC control group as compared with those in the Sham group, but each of these enhanced fibrotic markers decreased significantly in the TAC-ALK group (Figure 1G).

Bottom Line: The levels of signaling proteins were measured using Western blotting, while the expression of the relevant genes was analyzed using real-time QRT-PCR.These pathological alterations in TAC-mice were significantly ameliorated or blocked by ALK administration.In mechanically stretched cardiomyocytes, CGP53353 (a PKCβI inhibitor) prevented ERK phosphorylation and autophagic responses, while U0126 (an ERK inhibitor) blocked autophagic responses.

View Article: PubMed Central - PubMed

Affiliation: Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital and Institute of Biomedical Science, Fudan University, Shanghai 200032, China.

ABSTRACT

Aim: Aliskiren (ALK) is a renin inhibitor that has been used in the treatment of hypertension. The aim of this study was to determine whether ALK could ameliorate pressure overload-induced heart hypertrophy and fibrosis, and to elucidate the mechanisms of action.

Methods: Transverse aortic constriction (TAC) was performed in mice to induce heart pressure overload. ALK (150 mg·kg(-1)·d(-1), po), the autophagy inhibitor 3-methyladenine (10 mg·kg(-1) per week, ip) or the PKCβI inhibitor LY333531 (1 mg·kg(-1)·d-(1), po) was administered to the mice for 4 weeks. Heart hypertrophy, fibrosis and function were evaluated based on echocardiography, histological and biochemical measurements. Mechanically stretched cardiomyocytes of rats were used for in vitro experiments. The levels of signaling proteins were measured using Western blotting, while the expression of the relevant genes was analyzed using real-time QRT-PCR.

Results: TAC induced marked heart hypertrophy and fibrosis, accompanied by high levels of Ang II in plasma and heart, and by PKCβI/α and ERK1/2 phosphorylation in heart. Meanwhile, TAC induced autophagic responses in heart, i.e. increases in autophagic structures, expression of Atg5 and Atg16 L1 mRNAs and LC3-II and Beclin-1 proteins. These pathological alterations in TAC-mice were significantly ameliorated or blocked by ALK administration. In TAC-mice, 3-methyladenine administration also ameliorated heart hypertrophy, fibrosis and dysfunction, while LY333531 administration inhibited ERK phosphorylation and autophagy in heart. In mechanically stretched cardiomyocytes, CGP53353 (a PKCβI inhibitor) prevented ERK phosphorylation and autophagic responses, while U0126 (an ERK inhibitor) blocked autophagic responses.

Conclusion: ALK ameliorates heart hypertrophy, fibrosis and dysfunction in the mouse model in setting of chronic pressure overload, via suppressing Ang II-PKCβI-ERK1/2-regulated autophagy.

Show MeSH
Related in: MedlinePlus