Effects of CMYA1 overexpression on cardiac structure and function in mice

Figures

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  Figure 1.. Verification of CMYA1 overexpression in CMYA1-positive transgenic mice (A) PCR-based genotyping of the wild-type littermate control (wild-type C57 background) and CMYA1-OE mice using gDNA as the template. RT-PCR–based analysis of the expression level for the human CMYA1 gene: CMYA1 expression was high in CMYA1-OE transgenic mice but was not detectable in the wild-type C57 mice. NTG: non-transgenic; TG: transgenic. (B) Western blot analyses using an anti-FLAG antibody showed the obviously increased expression level of the CMYA1 protein in the CMYA1-OE transgenic mice (n=5) compared to the wild-type mice (n=4). **P<0.01. GAPDH was used as the loading control. (C,D) Immunocytochemistry (scale bar: 100 μm; C) and immunofluorescence (scale bar: 25 μm in the upper panel and 10 μm in the lower panel; D) assays both showed the increased CMYA1 expression level in the CMYA1-OE transgenic mice and the localization of CMYA1 expression at the ICDs of the myocardium (marked by white arrows). The white boxed areas in the upper panels are enlarged in the lower panels. ACTN2: α-actinin 2.

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  Figure 2.. Pathological changes in CMYA1 overexpression transgenic mice (A) Masson’s trichrome staining revealed obvious fibrosis in heart tissues from the CMYA1-OE transgenic mice; no fibrosis was evident for the wild-type control mice. The extent of fibrosis increased with time between the 6- and 9-month age time points. **P<0.01, n=5 for each group. (B) The 9-month-old CMYA1-OE mice heart tissues showed uneven bead width or interruption. The red arrows represent the intercalated disks and the mitochondria, respectively.

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  Figure 3.. Cx43 expression in CMYA1 overexpression transgenic mice (A) Western blot analyses using anti-Cx43 antibody revealed a decrease in the level of the Cx43 protein in the heart tissues from 9-month-old CMYA1-OE transgenic mice compared with that in age-matched littermate control mice. *P<0.05, n=3. (B) Immunofluorescence analysis showed that the Cx43 protein is localized at ICDs of the myocardium. (C) Co-immunoprecipitation assays revealed a physical interaction between CMYA1 and Cx43 in the extracts from heart tissues.

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  Figure 4.. Changes of cardiac function and electrophysiology in CMYA1-OE transgenic mice (A) Echocardiography examination of 6-month-old and 9-month-old mice indicated no significant differences in the left ventricular ejection fraction (EF) between CMYA1-OE transgenic mice and age-matched littermate controls (n=3). (B) Electrocardiogram measurements of 6-month-old mice revealed a ventricular bigeminy in the CMYA1-OE transgenic mice (n=3).