Epigallocatechin-3 gallate prevents pressure overload-induced heart failure by up-regulating SERCA2a via histone acetylation modification in mice

Abstract

Heart failure is a common, costly, and potentially fatal condition. The cardiac sarcoplasmic reticulum Ca-ATPase (SERCA2a) plays a critical role in the regulation of cardiac function. Previously, low SERCA2a expression was revealed in mice with heart failure. Epigallocatechin-3-gallate (EGCG) can function as an epigenetic regulator and has been reported to enhance cardiac function. However, the underlying epigenetic regulatory mechanism is still unclear. In this study, we investigated whether EGCG can up-regulate SERCA2a via histone acetylation and play role in preventing heart failure. For this, we generated a mouse model of heart failure by performing a minimally invasive transverse aortic constriction (TAC) operation and used this to test the effects of EGCG. The TAC+EGCG group showed nearly normal cardiac function compared to that in the SHAM group. The expression of SERCA2a was decreased at both the mRNA and protein levels in the TAC group but was enhanced in the TAC+EGCG group. Levels of AcH3 and AcH3K9 were determined to decrease near the promoter region of Atp2a2 (the gene encoding SERCA-2a) in the TAC group, but were elevated in the TAC+EGCG group. Meanwhile, HDAC1 activity and binding near the Atp2a2 promoter were increased in the TAC group but decreased with EGCG addition. Further, binding levels of GATA4 and Mef2c near the Atp2a2 promoter region were reduced in TAC hearts, which might have been caused by histone hypoacetylation; this was reversed by EGCG. Together, upregulation of SERCA2a via the modification of histone acetylation plays a role in EGCG-mediated prevention of pressure overload-induced heart failure, and this might represent a novel pharmacological target for the treatment of heart failure.

Fig 1. Efficacy of transverse aortic constriction (TAC) operation in mice.

A) Representative B-mode ultrasound image of the SHAM and TAC groups. B) Representative anatomical image of the TAC model. C) Representative pulse Doppler ultrasound image of the transverse aorta blood flow in the SHAM and TAC groups. D) The transverse aorta diameter decreased significantly after the TAC operation with or without epigallocatechin-3-gallate (EGCG) treatment (S1 Table). E) The velocity of the transverse aorta blood flow (P-mode ultrasound image) increased significantly after TAC with or without EGCG (S1 Table). Values are presented as the mean ± SE. *, P < 0.05 by two-way ANOVA; n = 8 per group.

Fig 2. Epigallocatechin-3-gallate (EGCG) prevents heart failure induced by pressure overload.

A) Representative M-mode ultrasound image of each group. Left ventricular anterior wall (LVAW), left ventricular internal diameter (LVID), and left ventricular posterior wall (LVPW) were increased significantly in the transverse aortic constriction (TAC) group. B) The heart weight to body weight ratio (HW/BW) was also higher in the TAC group than in the other groups at 12 weeks post-operation. Values are presented as the mean ± SE. *, P < 0.05 by two-way ANOVA; n = 8 per group.

Fig 3. Epigallocatechin-3-gallate (EGCG) prevents myocardial hypertrophy induced by pressure overload.

A) HE staining of left ventricle section showing that the cardiomyocyte size was larger in the transverse aortic constriction (TAC) group, and B) quantification of the cardiomyocyte diameter showing larger cardiomyocytes in the TAC group Values are presented as the mean ± SE. *, P < 0.05 by two-way ANOVA; n = 8 per group.

Fig 4. Epigallocatechin-3-gallate (EGCG) treatment increases the expression of SERCA2a upon heart failure.

A) SERCA2a mRNA expression was lower in the transverse aortic constriction (TAC) group than in the other groups. B) SERCA2a protein expression was also lower in the TAC group than in the other groups. Values are presented as the mean ± SE. *, P < 0.05 by two-way ANOVA; n = 8 per group.

Fig 5. Epigallocatechin-3-gallate (EGCG) reverses the hypoacetylation of AcH3 and AcH3K9 and inhibits HDAC1 binding near the Atp2a2 promoter region in mouse cardiac tissue after heart failure.

A) AcH3 binding near the Atp2a2 promoter region was significantly decreased in the transverse aortic constriction (TAC) compared to that in the other groups, as assessed by ChIP-qPCR. B) AcH3K9 binding near the Atp2a2 promoter region was also significantly decreased in the TAC group compared to that in the other groups. C) AcH3K4 binding near the Atp2a2 promoter region was not obviously different among the four groups. Values are presented as the mean ± SE. *, P < 0.05 by two-way ANOVA; n = 8 per group.

Fig 6. Epigallocatechin-3-gallate (EGCG) inhibits HDAC1 activity and binding near the Atp2a2 promoter region in mouse cardiac tissue after heart failure.

A) HDAC1 activity was determined in the hearts of mice with or without EGCG intervention. B) Binding levels of HDAC1 near the Atp2a2 promoter region were higher in the transverse aortic constriction (TAC) group than in the other groups. Values are presented as the mean ± SE. *, P < 0.05 by two-way ANOVA; n = 8 per group.

Fig 7. Epigallocatechin-3-gallate (EGCG) upregulates the binding of GATA4 and Mef2c near the Atp2a2 promoter region in cardiac tissues of mice after heart failure.

A) Binding levels of GATA4 near the Atp2a2 promoter region were reduced in hearts of the transverse aortic constriction (TAC) group, which was reversed by EGCG, as assessed by ChIP assays. B) Binding levels of Mef2c near the Atp2a2 promoter region were reduced in hearts of the TAC group, which was reversed by EGCG. Values are presented as the mean ± SE. *, P < 0.05 by two-way ANOVA; n = 8 per group.