Point mutations in murine Nkx2-5 phenocopy human congenital heart disease and induce pathogenic Wnt signaling
Milena B. Furtado, … , Nadia A. Rosenthal, Mauro W. Costa
Milena B. Furtado, … , Nadia A. Rosenthal, Mauro W. Costa
Published March 23, 2017
Citation Information: JCI Insight. 2017;2(6):e88271. https://doi.org/10.1172/jci.insight.88271.
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Research Article Cardiology Development

Point mutations in murine Nkx2-5 phenocopy human congenital heart disease and induce pathogenic Wnt signaling

Abstract

Mutations in the Nkx2-5 gene are a main cause of congenital heart disease. Several studies have addressed the phenotypic consequences of disrupting the Nkx2-5 gene locus, although animal models to date failed to recapitulate the full spectrum of the human disease. Here, we describe a new Nkx2-5 point mutation murine model, akin to its human counterpart disease–generating mutation. Our model fully reproduces the morphological and physiological clinical presentations of the disease and reveals an understudied aspect of Nkx2-5–driven pathology, a primary right ventricular dysfunction. We further describe the molecular consequences of disrupting the transcriptional network regulated by Nkx2-5 in the heart and show that Nkx2-5–dependent perturbation of the Wnt signaling pathway promotes heart dysfunction through alteration of cardiomyocyte metabolism. Our data provide mechanistic insights on how Nkx2-5 regulates heart function and metabolism, a link in the study of congenital heart disease, and confirms that our models are the first murine genetic models to our knowledge to present all spectra of clinically relevant adult congenital heart disease phenotypes generated by NKX2-5 mutations in patients.

Authors

Milena B. Furtado, Julia C. Wilmanns, Anjana Chandran, Joelle Perera, Olivia Hon, Christine Biben, Taylor J. Willow, Hieu T. Nim, Gurpreet Kaur, Stephanie Simonds, Qizhu Wu, David Willians, Ekaterina Salimova, Nicolas Plachta, James M. Denegre, Stephen A. Murray, Diane Fatkin, Michael Cowley, James T. Pearson, David Kaye, Mirana Ramialison, Richard P. Harvey, Nadia A. Rosenthal, Mauro W. Costa

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Figure 10

Wnt3a is upregulated in cardiac stress models and impairs mitochondrial respiration in Nkx2-5183P/+ neonatal cardiomyocytes.

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Wnt3a is upregulated in cardiac stress models and impairs mitochondrial ...
(A) qPCR shows an increase in Wnt3a expression in models of cardiac injury through hypoxia/reperfusion or myocardial infarction. Line represents control levels of Wnt3a in normoxic (hypoxia/reperfusion) and sham operated (myocardial infarction) mice. Results are shown as fold changes normalized by Hprt1 expression. (B) Supplementation of Wnt3a to primary neonatal cardiomyocytes leads to decreased mitochondrial membrane potential (n = 6), measured by JC-1 membrane permeant dye staining. (C) WT cardiomyocytes show better mitochondrial performance in all measured parameters when compared with Nkx2-5183P/+ (basal respiration, ATP production, proton leak, maximum respiration, and spare respiration). Upon Wnt3a stimulation, WT cardiomyocytes reduce energy consumption and increase spare respiratory capacity, while Nkx2-5183P/+ cardiomyocytes retain similar low levels of mytochondrial activity and dramatically increase nonmitochondrial respiration. n = 6. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001, unpaired t test equal variance 2 tailed. MI, myocardial infarction; H/R, hypoxia/reperfusion; OCR, oxygen consumption rate in picomols per minute.