Fog2 is critical for cardiac function and maintenance of coronary vasculature in the adult mouse heart
Bin Zhou, Qing Ma, Sek Won Kong, Yongwu Hu, Patrick H. Campbell, Francis X. McGowan, Kate G. Ackerman, Bingruo Wu, Bin Zhou, Sergei G. Tevosian, William T. Pu
Bin Zhou, Qing Ma, Sek Won Kong, Yongwu Hu, Patrick H. Campbell, Francis X. McGowan, Kate G. Ackerman, Bingruo Wu, Bin Zhou, Sergei G. Tevosian, William T. Pu
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Research Article Cardiology

Fog2 is critical for cardiac function and maintenance of coronary vasculature in the adult mouse heart

Abstract

Aberrant transcriptional regulation contributes to the pathogenesis of both congenital and adult forms of heart disease. While the transcriptional regulator friend of Gata 2 (FOG2) is known to be essential for heart morphogenesis and coronary development, its tissue-specific function has not been previously investigated. Additionally, little is known about the role of FOG2 in the adult heart. Here we used spatiotemporally regulated inactivation of Fog2 to delineate its function in both the embryonic and adult mouse heart. Early cardiomyocyte-restricted loss of Fog2 recapitulated the cardiac and coronary defects of the Fog2 germline murine knockouts. Later cardiomyocyte-restricted loss of Fog2 (Fog2MC) did not result in defects in cardiac structure or coronary vessel formation. However, Fog2MC adult mice had severely depressed ventricular function and died at 8–14 weeks. Fog2MC adult hearts displayed a paucity of coronary vessels, associated with myocardial hypoxia, increased cardiomyocyte apoptosis, and cardiac fibrosis. Induced inactivation of Fog2 in the adult mouse heart resulted in similar phenotypes, as did ablation of the FOG2 interaction with the transcription factor GATA4. Loss of the FOG2 or FOG2-GATA4 interaction altered the expression of a panel of angiogenesis-related genes. Collectively, our data indicate that FOG2 regulates adult heart function and coronary angiogenesis.

Authors

Bin Zhou, Qing Ma, Sek Won Kong, Yongwu Hu, Patrick H. Campbell, Francis X. McGowan, Kate G. Ackerman, Bingruo Wu, Bin Zhou, Sergei G. Tevosian, William T. Pu

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Figure 2

Abnormal heart development and coronary vasculogenesis after early cardiomyocyte-restricted Fog2 inactivation.

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Abnormal heart development and coronary vasculogenesis after early cardi...
(A and B) Control (Fog2fl/+Nkx2-5Cre/+) and littermate Fog2NK mutant embryos at E13.5. (C–H) Representative H&E staining of Fog2NK (right panels) and littermate control (left panels; Fog2fl/+Nkx2-5Cre/+) hearts at different levels. RA, right atrium; LA, left atrium; RV, right ventricle; A, aorta. The asterisk indicates AV cushion and the arrow indicates VSD. (I–K) PECAM whole-mount staining of Fog2NK and control (Fog2fl/+Nkx2-5Cre/+) hearts at E13.5. The coronary endothelial plexus coverage (ratio of region within black dotted line to total projected ventricular area) was significantly decreased in mutants. (*P < 0.05; n = 4–5 per group as indicated.) (L) Section of X-gal stained Tie2-Lz hearts showed decreased coronary vessels in the compact myocardial layer of Fog2NK mutant compared with Fog2fl/+Nkx2-5Cre/+ littermate control. Scale bar: 500 μm. Ventricles in the boxed regions are magnified (right panels).