Congenital Heart Disease (CHD), malformations of the heart present at birth, is the most common class of life-threatening birth defect. Atrioventricular Septal Defects (AVSDs) are a common and serious form of CHD in humans, comprising 5-10% of all CHD and a greater proportion of cases requiring surgical intervention. Gaining a mechanistic understanding of atrioventricular (AV) septation is an essential goal for improving clinical approaches to structural heart disease. This R01 renewal is based on a paradigm shift in the understanding of AV septation. Whereas the canonical view of AV septation was based on intracardiac events centered at the endocardial cushion, recent work demonstrated that cilia-required Sonic hedgehog (Shh) signaling in the Second Heart Field, outside of the heart proper, drives AV septation. During the last granting period, our laboratory significantly contributed towards this paradigm shift, both in the implication of cilia-based signaling (Kamp et al. 2010;Friedland- Little et al., 2011) and of Hedgehog signaling (Hoffmann et al, 2009;Xie et al, 2012). In this proposal, we harness a new understanding of AV septation to address the genetic etiology of AVSDs in humans and investigate the developmental mechanisms underlying AVSDs in more detail. We propose to (1) Perform targeted sequencing of the ciliome, Hedgehog signaling components, and cardiogenic transcription factors in a large cohort of AVSD patients;(2) analyze interactions between cilia genes, Hedgehog signaling components, and cardiogenic transcription factors in AVSDs;and (3) interrogate Hedgehog molecular networks in the cardiac progenitors that form the AV septum. The ultimate aim of the proposed work is to understand the genetic and molecular basis of AV septation. This proposal will increase understanding of the molecular ontogeny of human AVSDs. This work is an essential step towards defining the causes of human CHD and improving the natural history of patients with CHD.

Public Health Relevance

Congenital heart defects (CHD) are a leading cause of morbidity and mortality in infants, yet little is known about their etiology. Finding from the inital granting period implicated the cilia and Hedgehog signaling in Atrioventricular Septal Defects, a common form of serious CHD, in mice. This renewal tests the hypothesis that cilia and Hedgehog signaling defects cause Atrioventricular Septal Defects in humans, with implications for prevention and treatment of CHD.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
2R01HL092153-06
Application #
8791223
Study Section
Special Emphasis Panel (ZRG1-CVRS-P (02))
Program Officer
Schramm, Charlene A
Project Start
2008-04-01
Project End
2018-07-31
Budget Start
2014-08-01
Budget End
2015-07-31
Support Year
6
Fiscal Year
2014
Total Cost
$758,540
Indirect Cost
$186,514
Name
University of Chicago
Department
Pediatrics
Type
Schools of Medicine
DUNS #
005421136
City
Chicago
State
IL
Country
United States
Zip Code
60637
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Yang, Xinan H; Nadadur, Rangarajan D; Hilvering, Catharina Re et al. (2017) Transcription-factor-dependent enhancer transcription defines a gene regulatory network for cardiac rhythm. Elife 6:
Zhou, Lun; Liu, Jielin; Xiang, Menglan et al. (2017) Gata4 potentiates second heart field proliferation and Hedgehog signaling for cardiac septation. Proc Natl Acad Sci U S A 114:E1422-E1431
Priest, James R; Osoegawa, Kazutoyo; Mohammed, Nebil et al. (2016) De Novo and Rare Variants at Multiple Loci Support the Oligogenic Origins of Atrioventricular Septal Heart Defects. PLoS Genet 12:e1005963
Waldron, Lauren; Steimle, Jeffrey D; Greco, Todd M et al. (2016) The Cardiac TBX5 Interactome Reveals a Chromatin Remodeling Network Essential for Cardiac Septation. Dev Cell 36:262-75
Burnicka-Turek, Ozanna; Steimle, Jeffrey D; Huang, Wenhui et al. (2016) Cilia gene mutations cause atrioventricular septal defects by multiple mechanisms. Hum Mol Genet 25:3011-3028
Hoffmann, Andrew D; Yang, Xinan Holly; Burnicka-Turek, Ozanna et al. (2014) Foxf genes integrate tbx5 and hedgehog pathways in the second heart field for cardiac septation. PLoS Genet 10:e1004604
Xie, Linglin; Hoffmann, Andrew D; Burnicka-Turek, Ozanna et al. (2012) Tbx5-hedgehog molecular networks are essential in the second heart field for atrial septation. Dev Cell 23:280-91
Arnolds, David E; Liu, Fang; Fahrenbach, John P et al. (2012) TBX5 drives Scn5a expression to regulate cardiac conduction system function. J Clin Invest 122:2509-18
Smemo, Scott; Campos, Luciene C; Moskowitz, Ivan P et al. (2012) Regulatory variation in a TBX5 enhancer leads to isolated congenital heart disease. Hum Mol Genet 21:3255-63

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