Cardiac manifestations of human ACTA2 variants recapitulated in a zebrafish model

AbstractTheACTA2 gene encodes actin α2, a major smooth muscle protein in vascular smooth muscle cells. Missense variants in theACTA2 gene can cause inherited thoracic aortic diseases with characteristic symptoms, such as dysfunction of smooth muscle cells in the lungs, brain vessels, intestines, pupils, bladder, or heart. We identified a heterozygous missense variant of Gly148Arg (G148R) in a patient with a thoracic aortic aneurysm, dissection, and left ventricular non-compaction. We used zebrafish as an in vivo model to investigate whether or not the variants might cause functional or histopathological abnormalities in the heart. Following the fertilization of one-cell stage embryos, we injected in vitro synthesizedACTA2 mRNA of wild-type, novel variant G148R, or the previously known pathogenic variant Arg179His (R179H). The embryos were maintained and raised for 72  h post-fertilization for a heart analysis. Shortening fractions of heart were significantly reduced in both pathogenic variants. A histopathological evaluation showed that the myocardial wall ofACTA2 pathogenic variants was thinner than that of the wild type, and the total cell number within the myocardium was markedly decreased in all zebrafish with pathogenic variants mRNAs. Proliferating cell numbers were also significantly decreased in the endothelial and myocardial regions of zebrafish withACTA2 variants compared to the wild type. These results demonstrate the effects ofACTA2 G148R and R179H on the devel...
Source: Journal of Human Genetics - Category: Genetics & Stem Cells Source Type: research