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Cellular repressor of E1A-stimulated genes attenuates cardiac hypertrophy and fibrosis.

Bian Z, Cai J, Shen DF, Chen L, Yan L, Tang Q, Li H - J. Cell. Mol. Med. (2008)

Bottom Line: It has been proposed that CREG acts as a ligand that enhances differentiation and/or reduces cell proliferation.Constitutive over-expression of human CREG in the murine heart attenuated the hypertrophic response, markedly reduced inflammation.These beneficial effects were associated with attenuation of the mitogen-activated protein kinase (MAPK)-extracellular signal-regulated kinase 1 (MEK-ERK1)/2-dependent signalling cascade.

View Article: PubMed Central - PubMed

Affiliation: Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, PR China.

ABSTRACT
Cellular repressor of E1A-stimulated genes (CREG) is a secreted glycoprotein of 220 amino acids. It has been proposed that CREG acts as a ligand that enhances differentiation and/or reduces cell proliferation. CREG has been shown previously to attenuate cardiac hypertrophy in vitro. However, such a role has not been determined in vivo. In the present study, we tested the hypothesis that overexpression of CREG in the murine heart would protect against cardiac hypertrophy and fibrosis in vivo. The effects of constitutive human CREG expression on cardiac hypertrophy were investigated using both in vitro and in vivo models. Cardiac hypertrophy was produced by aortic banding and infusion of angiotensin II in CREG transgenic mice and control animals. The extent of cardiac hypertrophy was quantitated by two-dimensional and M-mode echocardiography as well as by molecular and pathological analyses of heart samples. Constitutive over-expression of human CREG in the murine heart attenuated the hypertrophic response, markedly reduced inflammation. Cardiac function was also preserved in hearts with increased CREG levels in response to hypertrophic stimuli. These beneficial effects were associated with attenuation of the mitogen-activated protein kinase (MAPK)-extracellular signal-regulated kinase 1 (MEK-ERK1)/2-dependent signalling cascade. In addition, CREG expression blocked fibrosis and collagen synthesis through blocking MEK-ERK1/2-dependent Smad 2/3 activation in vitro and in vivo. Therefore, the expression of CREG improves cardiac functions and inhibits cardiac hypertrophy, inflammation and fibrosis through blocking MEK-ERK1/2-dependent signalling.

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The effects of CREG on cardiac hypertrophy in vivo. (A and B) Gross hearts of sham and AB mice at 8 weeks after surgery or saline- or Ang II-infused mice at 4weeks of infusion. (C and D) Haematoxylin and eosin and wheat germ agglutinin (WGA) staining of sham and AB mice at 8 weeks after surgery. (E and F) Haematoxylin and eosin and WGA staining of 4 weeks of saline- and Ang II-infused mice. (G and H) Analysis of hypertrophic markers. Total RNA was isolated from hearts of mice of the indicated groups, and expression of transcripts for ANP, BNP, Myh-7 and Acta1 induced by AB or Ang II infusion were determined by real-time PCR analysis. Data represent typical results of three to four different experiments as mean ± S.E.M. (n= 4 to 6 mice/per group). *P < 0.01 was obtained for the WT/sham or WT/saline values.
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fig02: The effects of CREG on cardiac hypertrophy in vivo. (A and B) Gross hearts of sham and AB mice at 8 weeks after surgery or saline- or Ang II-infused mice at 4weeks of infusion. (C and D) Haematoxylin and eosin and wheat germ agglutinin (WGA) staining of sham and AB mice at 8 weeks after surgery. (E and F) Haematoxylin and eosin and WGA staining of 4 weeks of saline- and Ang II-infused mice. (G and H) Analysis of hypertrophic markers. Total RNA was isolated from hearts of mice of the indicated groups, and expression of transcripts for ANP, BNP, Myh-7 and Acta1 induced by AB or Ang II infusion were determined by real-time PCR analysis. Data represent typical results of three to four different experiments as mean ± S.E.M. (n= 4 to 6 mice/per group). *P < 0.01 was obtained for the WT/sham or WT/saline values.

Mentions: To determine whether cardiac overexpression of CREG antagonized the hypertrophic response to pressure overload, WT littermates and TG mice were subjected to AB surgery or sham operation. TG mice showed significant attenuation of hypertrophy after 8 weeks AB compared to WT littermates, as measured by the ratios of HW/BW, LW/BW and cardiomyocyte cross-sectional area (Table 1). No significant differences were observed in the sham-operated TG and WT mice. Cardiac dilatation, wall thickness and dysfunction were also inhibited or reversed in TG mice, as evidenced by improvements in left ventricular end-systolic diameter, left ventricular end-diastolic diameter, left ventricular posterior wall thickness, left ventricular septum, diastolic and percent fractional shortening (%FS) (Table 1). Gross hearts, haematoxylin and eosin and WGA staining further confirmed the inhibitory effect of CREG on cardiac remodelling after AB (Fig. 2A, C and D). We next examined the potential role of CREG on hypertrophy induced by Ang II infusion. Osmotic minipumps were implanted subcutaneously for a 4-week administration period, followed by cardiac functional assessment. The Ang II-induced increase in HW/BW and LW/BW as well as cardiomyocyte cross-sectional area were also attenuated in TG mice compared to WT mice (Table 2). Cardiac-specific overex-pression of CREG abrogated Ang II-induced cardiac chamber dilatation and wall thickness in both systole and diastole (Table 2). These findings were confirmed by histological analysis (Fig. 2B, E and F). Atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP), myosin heavy polypeptide 7 cardiac muscle β (Myh7), and actin α1 skeletal muscle (Acta1) are markers for cardiac hypertrophy [13]. To determine whether CREG affected the mRNA expression levels of these markers, we performed real-time PCR. Our results showed that the induction of these hypertrophic genes was severely blunted in TG mice in response to AB and Ang II infusion (Fig. 2G and H). These findings suggest that CREG prevents the development of cardiac hypertrophy induced by pressure overload or Ang II stimulation in vivo.


Cellular repressor of E1A-stimulated genes attenuates cardiac hypertrophy and fibrosis.

Bian Z, Cai J, Shen DF, Chen L, Yan L, Tang Q, Li H - J. Cell. Mol. Med. (2008)

The effects of CREG on cardiac hypertrophy in vivo. (A and B) Gross hearts of sham and AB mice at 8 weeks after surgery or saline- or Ang II-infused mice at 4weeks of infusion. (C and D) Haematoxylin and eosin and wheat germ agglutinin (WGA) staining of sham and AB mice at 8 weeks after surgery. (E and F) Haematoxylin and eosin and WGA staining of 4 weeks of saline- and Ang II-infused mice. (G and H) Analysis of hypertrophic markers. Total RNA was isolated from hearts of mice of the indicated groups, and expression of transcripts for ANP, BNP, Myh-7 and Acta1 induced by AB or Ang II infusion were determined by real-time PCR analysis. Data represent typical results of three to four different experiments as mean ± S.E.M. (n= 4 to 6 mice/per group). *P < 0.01 was obtained for the WT/sham or WT/saline values.
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Related In: Results  -  Collection

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fig02: The effects of CREG on cardiac hypertrophy in vivo. (A and B) Gross hearts of sham and AB mice at 8 weeks after surgery or saline- or Ang II-infused mice at 4weeks of infusion. (C and D) Haematoxylin and eosin and wheat germ agglutinin (WGA) staining of sham and AB mice at 8 weeks after surgery. (E and F) Haematoxylin and eosin and WGA staining of 4 weeks of saline- and Ang II-infused mice. (G and H) Analysis of hypertrophic markers. Total RNA was isolated from hearts of mice of the indicated groups, and expression of transcripts for ANP, BNP, Myh-7 and Acta1 induced by AB or Ang II infusion were determined by real-time PCR analysis. Data represent typical results of three to four different experiments as mean ± S.E.M. (n= 4 to 6 mice/per group). *P < 0.01 was obtained for the WT/sham or WT/saline values.
Mentions: To determine whether cardiac overexpression of CREG antagonized the hypertrophic response to pressure overload, WT littermates and TG mice were subjected to AB surgery or sham operation. TG mice showed significant attenuation of hypertrophy after 8 weeks AB compared to WT littermates, as measured by the ratios of HW/BW, LW/BW and cardiomyocyte cross-sectional area (Table 1). No significant differences were observed in the sham-operated TG and WT mice. Cardiac dilatation, wall thickness and dysfunction were also inhibited or reversed in TG mice, as evidenced by improvements in left ventricular end-systolic diameter, left ventricular end-diastolic diameter, left ventricular posterior wall thickness, left ventricular septum, diastolic and percent fractional shortening (%FS) (Table 1). Gross hearts, haematoxylin and eosin and WGA staining further confirmed the inhibitory effect of CREG on cardiac remodelling after AB (Fig. 2A, C and D). We next examined the potential role of CREG on hypertrophy induced by Ang II infusion. Osmotic minipumps were implanted subcutaneously for a 4-week administration period, followed by cardiac functional assessment. The Ang II-induced increase in HW/BW and LW/BW as well as cardiomyocyte cross-sectional area were also attenuated in TG mice compared to WT mice (Table 2). Cardiac-specific overex-pression of CREG abrogated Ang II-induced cardiac chamber dilatation and wall thickness in both systole and diastole (Table 2). These findings were confirmed by histological analysis (Fig. 2B, E and F). Atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP), myosin heavy polypeptide 7 cardiac muscle β (Myh7), and actin α1 skeletal muscle (Acta1) are markers for cardiac hypertrophy [13]. To determine whether CREG affected the mRNA expression levels of these markers, we performed real-time PCR. Our results showed that the induction of these hypertrophic genes was severely blunted in TG mice in response to AB and Ang II infusion (Fig. 2G and H). These findings suggest that CREG prevents the development of cardiac hypertrophy induced by pressure overload or Ang II stimulation in vivo.

Bottom Line: It has been proposed that CREG acts as a ligand that enhances differentiation and/or reduces cell proliferation.Constitutive over-expression of human CREG in the murine heart attenuated the hypertrophic response, markedly reduced inflammation.These beneficial effects were associated with attenuation of the mitogen-activated protein kinase (MAPK)-extracellular signal-regulated kinase 1 (MEK-ERK1)/2-dependent signalling cascade.

View Article: PubMed Central - PubMed

Affiliation: Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, PR China.

ABSTRACT
Cellular repressor of E1A-stimulated genes (CREG) is a secreted glycoprotein of 220 amino acids. It has been proposed that CREG acts as a ligand that enhances differentiation and/or reduces cell proliferation. CREG has been shown previously to attenuate cardiac hypertrophy in vitro. However, such a role has not been determined in vivo. In the present study, we tested the hypothesis that overexpression of CREG in the murine heart would protect against cardiac hypertrophy and fibrosis in vivo. The effects of constitutive human CREG expression on cardiac hypertrophy were investigated using both in vitro and in vivo models. Cardiac hypertrophy was produced by aortic banding and infusion of angiotensin II in CREG transgenic mice and control animals. The extent of cardiac hypertrophy was quantitated by two-dimensional and M-mode echocardiography as well as by molecular and pathological analyses of heart samples. Constitutive over-expression of human CREG in the murine heart attenuated the hypertrophic response, markedly reduced inflammation. Cardiac function was also preserved in hearts with increased CREG levels in response to hypertrophic stimuli. These beneficial effects were associated with attenuation of the mitogen-activated protein kinase (MAPK)-extracellular signal-regulated kinase 1 (MEK-ERK1)/2-dependent signalling cascade. In addition, CREG expression blocked fibrosis and collagen synthesis through blocking MEK-ERK1/2-dependent Smad 2/3 activation in vitro and in vivo. Therefore, the expression of CREG improves cardiac functions and inhibits cardiac hypertrophy, inflammation and fibrosis through blocking MEK-ERK1/2-dependent signalling.

Show MeSH
Related in: MedlinePlus