This grant application focuses on the regulation and function of Pax3 in neural crest ceils. Neural crest plays important roles in cardiovascular development since derivatives contribute to the outflow tract of the heart and to the great vessels. Mutations in neural crest genes, including Pax3, lead to congenital heart disease. This competitive renewal application builds upon significant data and resources that we have developed during the first granting cycle in order to elucidate the molecular pathways responsible for regulating Pax3 expression in neural crest. Neural crest cells represent an exciting and tractable embryonic example of a multipotent precursor cell population that is capable of differentiating along multiple cell fate pathways. Pax3 is expressed by multipotent neural crest progenitors, and our preliminary data indicate that it is also expressed by some adult neural crest-derived stem cells. However, Pax3 expression always abates prior to terminal differentiation of multipotent progenitors. Previous studies have documented the requirement for Pax3 expression during development. Here, we propose that Pax3 inactivation is also critical. We will test the novel hypothesis that Pax3 is required to maintain the multipotent, undifferentiated phenotype of neural crest cells. This will be examined in animal models, in cell-based systems, and at the transcriptional level, taking advantage of our identification of a novel downstream target of Pax3, dopachrome tautomerase (DCT). DCT is an enzyme required for melanin synthesis in melanocytes (neural crest derivatives) that we now show is also expressed in a pattern reminiscent of the developing AV node. In the absence of Pax3, DCT expression is lost in both melanocytes and the heart. We suggest that Pax3 and neural crest are required for development of some aspects of the cardiac conduction system. We will test whether Pax3 regulates DCT directly or indirectly during cardiac development, and we will define the role of DCT in the heart. Therefore, aim 1 will define upstream molecular pathways regulating Pax3 in neural crest while aims 2 and 3 define mechanisms of Pax3 function during cardiac development at the molecular and whole organ level. The approaches in aim 2 are relevant to an understanding of how neural crest stem cell multipotency is maintained during critical periods of cardiac and embryonic development.
Aim 3 examines the role of neural crest during development of the conduction system, and specifically examines Pax3 regulation of DCT. ? ?

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL061475-10
Application #
7458738
Study Section
Cardiovascular and Pulmonary Research A Study Section (CVA)
Program Officer
Schramm, Charlene A
Project Start
1999-07-07
Project End
2010-06-30
Budget Start
2008-07-01
Budget End
2010-06-30
Support Year
10
Fiscal Year
2008
Total Cost
$375,716
Indirect Cost
Name
University of Pennsylvania
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Degenhardt, Karl R; Milewski, Rita C; Padmanabhan, Arun et al. (2010) Distinct enhancers at the Pax3 locus can function redundantly to regulate neural tube and neural crest expressions. Dev Biol 339:519-27
Wu, Meilin; Li, Jun; Engleka, Kurt A et al. (2008) Persistent expression of Pax3 in the neural crest causes cleft palate and defective osteogenesis in mice. J Clin Invest 118:2076-87
High, Frances A; Lu, Min Min; Pear, Warren S et al. (2008) Endothelial expression of the Notch ligand Jagged1 is required for vascular smooth muscle development. Proc Natl Acad Sci U S A 105:1955-9
Engleka, Kurt A; Wu, Meilin; Zhang, Maozhen et al. (2007) Menin is required in cranial neural crest for palatogenesis and perinatal viability. Dev Biol 311:524-37
High, Frances A; Zhang, Maozhen; Proweller, Aaron et al. (2007) An essential role for Notch in neural crest during cardiovascular development and smooth muscle differentiation. J Clin Invest 117:353-63
St Amand, Tara R; Lu, Jonathan T; Zamora, Monica et al. (2006) Distinct roles of HF-1b/Sp4 in ventricular and neural crest cells lineages affect cardiac conduction system development. Dev Biol 291:208-17
Schienda, Jaclyn; Engleka, Kurt A; Jun, Susan et al. (2006) Somitic origin of limb muscle satellite and side population cells. Proc Natl Acad Sci U S A 103:945-50
Luo, Yang; High, Frances A; Epstein, Jonathan A et al. (2006) N-cadherin is required for neural crest remodeling of the cardiac outflow tract. Dev Biol 299:517-28
Liu, Shasha; Liu, Fangyu; Schneider, Amanda E et al. (2006) Distinct cardiac malformations caused by absence of connexin 43 in the neural crest and in the non-crest neural tube. Development 133:2063-73
Milewski, Rita C; Chi, Neil C; Li, Jun et al. (2004) Identification of minimal enhancer elements sufficient for Pax3 expression in neural crest and implication of Tead2 as a regulator of Pax3. Development 131:829-37

Showing the most recent 10 out of 29 publications