A transgenic rabbit model for human hypertrophic cardiomyopathy
Ali J. Marian, … , Miguel Quinones, Robert Roberts
Ali J. Marian, … , Miguel Quinones, Robert Roberts
Published December 15, 1999
Citation Information: J Clin Invest. 1999;104(12):1683-1692. https://doi.org/10.1172/JCI7956.
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A transgenic rabbit model for human hypertrophic cardiomyopathy

Abstract

Certain mutations in genes for sarcomeric proteins cause hypertrophic cardiomyopathy (HCM). We have developed a transgenic rabbit model for HCM caused by a common point mutation in the β-myosin heavy chain (MyHC) gene, R400Q. Wild-type and mutant human β-MyHC cDNAs were cloned 3′ to a 7-kb murine β-MyHC promoter. We injected purified transgenes into fertilized zygotes to generate two lines each of the wild-type and mutant transgenic rabbits. Expression of transgene mRNA and protein were confirmed by Northern blotting and 2-dimensional gel electrophoresis followed by immunoblotting, respectively. Animals carrying the mutant transgene showed substantial myocyte disarray and a 3-fold increase in interstitial collagen expression in their myocardia. Mean septal thicknesses were comparable between rabbits carrying the wild type transgene and their nontransgenic littermates (NLMs) but were significantly increased in the mutant transgenic animals. Posterior wall thickness and left ventricular mass were also increased, but dimensions and systolic function were normal. Premature death was more common in mutant than in wild-type transgenic rabbits or in NLMs. Thus, cardiac expression of β-MyHC-Q403 in transgenic rabbits induced hypertrophy, myocyte and myofibrillar disarray, interstitial fibrosis, and premature death, phenotypes observed in humans patients with HCM due to β-MyHC-Q403.

Authors

Ali J. Marian, Yun Wu, Do-Sun Lim, Meghan McCluggage, Keith Youker, Qun-tao Yu, Ramon Brugada, Francesco DeMayo, Miguel Quinones, Robert Roberts

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Figure 2

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Expression of the transgene mRNA in cardiac and noncardiac tissues. (a) ...
Expression of the transgene mRNA in cardiac and noncardiac tissues. (a) Expression of the full-length transgene mRNA in the heart detected by Northern blotting. Lane 1 represents a positive control (human heart), lane 2 represents a negative control (nontransgenic rabbit), lanes 2 and 3 represent 2 lines of wild-type mutant transgenic rabbits, and lanes 4 and 5 represent 2 lines of mutant transgenic rabbits. As shown, a 6-kb band was detected in lanes 1 (positive control) and 2–6 (transgenic rabbits), but it was absent in lane 2 (a negative control). The lower blot represents GAPDH mRNA, which was used to control for loading conditions. (b) Expression pattern of the endogenous β-MyHC mRNA in noncardiac tissues in a nontransgenic littermate (NLM) rabbit detected by RT-PCR. RT controls (RT–), genomic DNA (labeled as DNA), and a PCR negative control (–control) are also included. As shown, a 368-bp RT product was present in lanes representing left ventricle (LV), left atrium (LA), and skeletal muscles (SK) after RT, but was absent in lanes representing lungs and aorta. (c) Expression pattern of the transgene mRNA in noncardiac tissues. Transgene construct and a human heart (HH) sample were included as positive controls and RT– and PCR negative controls were included as negative controls. As shown, a 340-bp band was present in lanes representing transgene (positive control), HH (positive control), LV, LA, and SK after RT. It was absent in lanes representing lungs and aorta.