Islet1 Derivatives in the Heart Are of Both Neural Crest and Second Heart Field Origin

Department of Cell and Developmental Biology, Cardiovascular Institute and Institute for Regenerative Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA.
Circulation Research (Impact Factor: 11.02). 03/2012; 110(7):922-6. DOI: 10.1161/CIRCRESAHA.112.266510
Source: PubMed


Islet1 (Isl1) has been proposed as a marker of cardiac progenitor cells derived from the second heart field and is utilized to identify and purify cardiac progenitors from murine and human specimens for ex vivo expansion. The use of Isl1 as a specific second heart field marker is dependent on its exclusion from other cardiac lineages such as neural crest.
Determine whether Isl1 is expressed by cardiac neural crest.
We used an intersectional fate-mapping system using the RC::FrePe allele, which reports dual Flpe and Cre recombination. Combining Isl1(Cre/+), a SHF driver, and Wnt1::Flpe, a neural crest driver, with Rc::FrePe reveals that some Isl1 derivatives in the cardiac outflow tract derive from Wnt1-expressing neural crest progenitors. In contrast, no overlap was observed between Wnt1-derived neural crest and an alternative second heart field driver, Mef2c-AHF-Cre.
Isl1 is not restricted to second heart field progenitors in the developing heart but also labels cardiac neural crest. The intersection of Isl1 and Wnt1 lineages within the heart provides a caveat to using Isl1 as an exclusive second heart field cardiac progenitor marker and suggests that some Isl1-expressing progenitor cells derived from embryos, embryonic stem cultures, or induced pluripotent stem cultures may be of neural crest lineage.

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Available from: Rachael Brust, Oct 03, 2015
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    • "In the regions of the heart, the cNCC contribute mesenchyme for the septation of the outflow tract, the morphogenesis of the great arteries, and the maturation of the atrioventricular valves and the conduction system (Kirby and Hutson, 2010; Keyte and Hutson, 2012). Abnormal development of these structures, secondary to a loss of cNCC, has been postulated to represent a significant proportion of congenital heart defects (Porras and Brown, 2008; Rentschler et al., 2010; Engleka et al., 2012), thus the identification of factors that influence cNCC migration and development is of significant interest. In this study, we used primary cultures of cardiac NCC to test the hypothesis that a deficit of Zn can result in impaired NCC viability and function, and thus potentially contribute to the type of heart anomalies that have been observed in fetuses obtained from Zn-deficient animals. "
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    ABSTRACT: BACKGROUND Developmental zinc (Zn) deficiency increases the incidence of heart anomalies in rat fetuses, in regions and structures derived from the outflow tract. Given that the development of the outflow tract requires the presence of cardiac neural crest cells (cNCC), we speculated that Zn deficiency selectively kills cNCC and could lead to heart malformations.METHODS Cardiac NCC were isolated from E10.5 rat embryos and cultured in control media (CTRL), media containing 3 μM of the cell permeable metal chelator N, N, N′, N′-tetrakis (2-pyridylmethyl) ethylene diamine (TPEN), or in TPEN-treated media supplemented with 3 μM Zn (TPEN + Zn). Cardiac NCC were collected after 6, 8, and 24 h of treatment to assess cell viability, proliferation, and apoptosis.RESULTSThe addition of TPEN to the culture media reduced free intracellular Zn pools and cell viability as assessed by low ATP production, compared to cells grown in control or Zn-supplemented media. There was an accumulation of reactive oxygen species, a release of mitochondrial cytochrome c into the cytoplasm, and an increased cellular expression of active caspase-3 in TPEN-treated cNCC compared to cNCC cultured in CTRL or TPEN + Zn media.CONCLUSION Zn deficiency can result in oxidative stress in cNCC, and subsequent decreases in their population and metabolic activity. These data support the concept that Zn deficiency associated developmental heart defects may arise in part as a consequence of altered cNCC metabolism
    Birth Defects Research Part B Developmental and Reproductive Toxicology 02/2015; 104(1). DOI:10.1002/bdrb.21135 · 0.77 Impact Factor
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    • "Despite the key role of Isl1, this transcription factor is not considered an indubitable marker of this subpopulation of SHF progenitor cells. It has been demonstrated very recently that Isl1 labels both SHF precursors and some cardiac neural crest cells and that Mef2C is a more efficient marker of the SHF progenitor cells in labelling experiments.11 This paper indirectly suggests both a review of past literature in view of these new data and using a different marker in studies of the SHF progenitor cells. "
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    ABSTRACT: Cardiac progenitor cells are multipotent stem cells isolated from both embryonic and adult hearts in several species and are able to differentiate at least into smooth muscle cells, endothelial cells and cardiomyocytes. The embryonic origin of these cells has not yet been demonstrated, but it has been suggested that these cells may derive from the first and secondary heart fields and from the neural crest. In the last decade, two diffe-rent populations of cardiac progenitor or stem cells have been identified and isolated, i.e., the Islet1 positive (Isl1+) and c-Kit positive (c-Kit+)/Stem Cell Antigen-1 positive (Sca-1+) cells. Until 2012, these two populations have been considered two separate entities with different roles and a different origin, but new evidence now suggests a con-nection between the two populations and that the two populations may represent two subpopulations of a unique pool of cardiac stem cells, derived from a common immature primitive cell. To find a common consensus on this concept is very important in furthe-ring the application of stem cells to cardiac tissue engineering.
    European journal of histochemistry: EJH 04/2013; 57(2):e14. DOI:10.4081/ejh.2013.e14 · 2.04 Impact Factor
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    • "This ex vivo data is consistent with in vivo fate-mapping studies, using an Isl1 inducible Cre, showing the contribution of Isl1 derivatives to the same three lineages [28]. Recent evidence suggests that some Isl1-expressing progenitor cells may also be of a NC lineage (discussed below) [62]. "
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    ABSTRACT: Jun is a highly conserved member of the multimeric activator protein 1 transcription factor complex and plays an important role in human cancer where it is known to be critical for proliferation, cell cycle regulation, differentiation, and cell death. All of these biological functions are also crucial for embryonic development. Although all Jun null mouse embryos die at mid-gestation with persistent truncus arteriosus, a severe cardiac outflow tract defect also seen in human congenital heart disease, the developmental mechanisms are poorly understood. Here we show that murine Jun is expressed in a restricted pattern in several cell populations important for cardiovascular development, including the second heart field, pharyngeal endoderm, outflow tract and atrioventricular endocardial cushions and post-migratory neural crest derivatives. Several genes, including Isl1, molecularly mark the second heart field. Isl1 lineages include myocardium, smooth muscle, neural crest, endocardium, and endothelium. We demonstrate that conditional knockout mouse embryos lacking Jun in Isl1-expressing progenitors display ventricular septal defects, double outlet right ventricle, semilunar valve hyperplasia and aortic arch artery patterning defects. In contrast, we show that conditional deletion of Jun in Tie2-expressing endothelial and endocardial precursors does not result in aortic arch artery patterning defects or embryonic death, but does result in ventricular septal defects and a low incidence of semilunar valve defects, atrioventricular valve defects and double outlet right ventricle. Our results demonstrate that Jun is required in Isl1-expressing progenitors and, to a lesser extent, in endothelial cells and endothelial-derived endocardium for cardiovascular development but is dispensable in both cell types for embryonic survival. These data provide a cellular framework for understanding the role of Jun in the pathogenesis of congenital heart disease.
    PLoS ONE 02/2013; 8(2):e57032. DOI:10.1371/journal.pone.0057032 · 3.23 Impact Factor
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