Faculty Collaboration Database

Mouse Model of Human Congenital Heart Disease: Progressive Atrioventricular Block Induced by a Heterozygous Nkx2-5 Homeodomain Missense Mutation. Circ Arrhythm Electrophysiol 2015 Oct;8(5):1255-64

Date

08/01/2015

Pubmed ID

26226998

Pubmed Central ID

PMC4618020

DOI

10.1161/CIRCEP.115.002720

Scopus ID

2-s2.0-84944676794 (requires institutional sign-in at Scopus site)   26 Citations

Abstract

BACKGROUND: Heterozygous human NKX2-5 homeodomain (DNA-binding domain) missense mutations are highly penetrant for varied congenital heart defects, including progressive atrioventricular (AV) block requiring pacemaker implantation. We recently replicated this genetic defect in a murine knockin model, in which we demonstrated highly penetrant, pleiotropic cardiac anomalies. In this study, we examined postnatal AV conduction in the knockin mice.

METHODS AND RESULTS: A murine knockin model (Arg52Gly, Nkx2-5(+/R52G)) in a 129/Sv background was analyzed by histopathology, surface, and telemetry ECG, and in vivo electrophysiology studies, comparing with control Nkx2-5(+/+) mice at diverse postnatal stages, ranging from postnatal day 1 (P1) to 17 months. PR prolongation (first degree AV block) was present at 4 weeks, 7 months, and 17 months of age, but not at P1 in the mutant mice. Advanced AV block was also occasionally demonstrated in the mutant mice. Electrophysiology studies showed that AV nodal function and right ventricular effective refractory period were impaired in the mutant mice, whereas sinus nodal function was not affected. AV nodal size was significantly smaller in the mutant mice than their controls at 4 weeks of age, corresponding to the presence of PR prolongation, but not P1, suggesting, at least in part, that the conduction abnormalities are the result of a morphologically atrophic AV node.

CONCLUSIONS: The highly penetrant and progressive AV block phenotype seen in human heterozygous missense mutations in NKX2-5 homeodomain was replicated in mice by knocking in a comparable missense mutation.

Author List

Chowdhury R, Ashraf H, Melanson M, Tanada Y, Nguyen M, Silberbach M, Wakimoto H, Benson DW, Anderson RH, Kasahara H

MESH terms used to index this publication - Major topics in bold

Animals
Atrioventricular Block
Disease Models, Animal
Electrocardiography
Electrophysiologic Techniques, Cardiac
Heart Defects, Congenital
Heterozygote
Homeobox Protein Nkx-2.5
Homeodomain Proteins
Humans
Mice
Mutation, Missense
Phenotype
Transcription Factors