201
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Aanhaanen WTJ, Boukens BJD, Sizarov A, Wakker V, de Gier-de Vries C, van Ginneken AC, Moorman AFM, Coronel R, Christoffels VM. Defective Tbx2-dependent patterning of the atrioventricular canal myocardium causes accessory pathway formation in mice. J Clin Invest 2011; 121:534-44. [PMID: 21266775 DOI: 10.1172/jci44350] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Accepted: 11/01/2010] [Indexed: 11/17/2022] Open
Abstract
Ventricular preexcitation, a feature of Wolff-Parkinson-White syndrome, is caused by accessory myocardial pathways that bypass the annulus fibrosus. This condition increases the risk of atrioventricular tachycardia and, in the presence of atrial fibrillation, sudden death. The developmental mechanisms underlying accessory pathway formation are poorly understood but are thought to primarily involve malformation of the annulus fibrosus. Before birth, slowly conducting atrioventricular myocardium causes a functional atrioventricular activation delay in the absence of the annulus fibrosus. This myocardium remains present after birth, suggesting that the disturbed development of the atrioventricular canal myocardium may mediate the formation of rapidly conducting accessory pathways. Here we show that myocardium-specific inactivation of T-box 2 (Tbx2), a transcription factor essential for atrioventricular canal patterning, leads to the formation of fast-conducting accessory pathways, malformation of the annulus fibrosus, and ventricular preexcitation in mice. The accessory pathways ectopically express proteins required for fast conduction (connexin-40 [Cx40], Cx43, and sodium channel, voltage-gated, type V, α [Scn5a]). Additional inactivation of Cx30.2, a subunit for gap junctions with low conductance expressed in the atrioventricular canal and unaffected by the loss of Tbx2, did not affect the functionality of the accessory pathways. Our results suggest that malformation of the annulus fibrosus and preexcitation arise from the disturbed development of the atrioventricular myocardium.
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Affiliation(s)
- Wim T J Aanhaanen
- Heart Failure Research Center, University of Amsterdam, Amsterdam, The Netherlands
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202
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Murphy BL, Pun RYK, Yin H, Faulkner CR, Loepke AW, Danzer SC. Heterogeneous integration of adult-generated granule cells into the epileptic brain. J Neurosci 2011; 31:105-17. [PMID: 21209195 PMCID: PMC3022369 DOI: 10.1523/jneurosci.2728-10.2011] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 09/08/2010] [Accepted: 10/21/2010] [Indexed: 11/21/2022] Open
Abstract
The functional impact of adult-generated granule cells in the epileptic brain is unclear, with data supporting both protective and maladaptive roles. These conflicting findings could be explained if new granule cells integrate heterogeneously, with some cells taking neutral or adaptive roles and others contributing to recurrent circuitry supporting seizures. Here, we tested this hypothesis by completing detailed morphological characterizations of age- and experience-defined cohorts of adult-generated granule cells from transgenic mice. The majority of newborn cells exposed to an epileptogenic insult exhibited reductions in dendritic spine number, suggesting reduced excitatory input to these cells. A significant subset, however, exhibited higher spine numbers. These latter cells tended to have enlarged cell bodies, long basal dendrites, or both. Moreover, cells with basal dendrites received significantly more recurrent mossy fiber input through their apical dendrites, indicating that these cells are robustly integrated into the pathological circuitry of the epileptic brain. These data imply that newborn cells play complex--and potentially conflicting--roles in epilepsy.
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Affiliation(s)
- Brian L. Murphy
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
- Program in Neuroscience, University of Cincinnati, Cincinnati, Ohio 45229
| | - Raymund Y. K. Pun
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
| | - Hulian Yin
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
| | - Christian R. Faulkner
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
| | - Andreas W. Loepke
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
- Departments of Anesthesia and Pediatrics, University of Cincinnati, Cincinnati, Ohio 45221, and
- Program in Neuroscience, University of Cincinnati, Cincinnati, Ohio 45229
| | - Steve C. Danzer
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229
- Departments of Anesthesia and Pediatrics, University of Cincinnati, Cincinnati, Ohio 45221, and
- Program in Neuroscience, University of Cincinnati, Cincinnati, Ohio 45229
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203
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Embryonic Pax7-expressing progenitors contribute multiple cell types to the postnatal olfactory epithelium. J Neurosci 2010; 30:9523-32. [PMID: 20631180 DOI: 10.1523/jneurosci.0867-10.2010] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Prolonged neurogenesis driven by stem/progenitor cells is a hallmark of the olfactory epithelium (OE), beginning at the placodal stages in the embryo and continuing throughout adult life. Despite the progress made to identify and study the regulation of adult OE progenitors, our knowledge of embryonic OE precursors and their cellular contributions to the adult OE has been stalled by the lack of markers able to distinguish individual candidate progenitors. Here we identify embryonic OE Pax7+ progenitors, detected at embryonic day 10.5 (E10.5) in the olfactory pit with an antigen profile and location previously assigned to presumptive OE stem cells. Using Cre-loxP technology (Pax7-cre/ROSA YFP mice), we expose a wide range of derivatives, including CNS and olfactory neurons, non-neuronal cells, and olfactory ensheathing glia, all made from embryonic Pax7+ cells. Importantly, the expression of Pax7 in the embryonic OE is downregulated from E15.5, such that after birth, no Pax7+ cells are found in the OE, and thus the progenitor population here identified is restricted to embryonic stages. Our results provide the first evidence for a population of Pax7-expressing embryonic progenitors that contribute to multiple OE lineages and demonstrate novel insights into the unique spatiotemporal patterning of the postnatal OE.
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204
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Lin X, Huo Z, Liu X, Zhang Y, Li L, Zhao H, Yan B, Liu Y, Yang Y, Chen YH. A novel GATA6 mutation in patients with tetralogy of Fallot or atrial septal defect. J Hum Genet 2010; 55:662-7. [DOI: 10.1038/jhg.2010.84] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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205
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Developmental origin of the neuronal subtypes that comprise the amygdalar fear circuit in the mouse. J Neurosci 2010; 30:6944-53. [PMID: 20484636 DOI: 10.1523/jneurosci.5772-09.2010] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We have taken a genetic-based fate-mapping approach to determine the specific contributions of telencephalic progenitors to the structures that comprise the amygdalar fear circuit including the central (CA), lateral (LA), and basolateral (BLA) amygdala. Our data indicate that progenitors in the ventral pallium (VP) contribute projection neurons to the LA and BLA but not the CA. Rather, the CA appears to derive, at least in part, from progenitors located in the ventral lateral ganglionic eminence (vLGE). Diverse groups of interneurons populate these amygdalar nuclei, and as predicted our data support the notion that they originate from subpallial progenitors. A rather specific population of amygdalar interneurons, the intercalated cells (ITCs), is known to play a fundamental role in fear-related behaviors. However, no information on their specific origin has, as yet, been provided. Our findings suggest that the ITCs arise from the dorsal lateral ganglionic eminence (dLGE) and migrate in the lateral migratory stream to populate the paracapsular regions as well as the main intercalated mass of the amygdala (IA). Germ-line Gsx2 mutants are known to exhibit an expansion of the VP into the LGE and a concomitant reduction in the dLGE and vLGE. Accordingly, Gsx2 conditional mutants display a significantly enlarged LA and a significant reduction in ITCs both within the paracapsular regions and the IA. Additional support for a dLGE origin of the ITCs was obtained in conditional mutants of the dLGE gene Sp8. Thus, our findings indicate diverse origins for the neuronal components that comprise the amygdalar fear circuit.
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206
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In vivo proliferation of postmitotic cochlear supporting cells by acute ablation of the retinoblastoma protein in neonatal mice. J Neurosci 2010; 30:5927-36. [PMID: 20427652 DOI: 10.1523/jneurosci.5989-09.2010] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Cochlear hair cells (HCs) are mechanosensory receptors that transduce sound into electrical signals. HC damage in nonmammalian vertebrates induces surrounding supporting cells (SCs) to divide, transdifferentiate and replace lost HCs; however, such spontaneous HC regeneration does not occur in the mammalian cochlea. Here, we acutely ablate the retinoblastoma protein (Rb), a crucial cell cycle regulator, in two subtypes of postmitotic SCs (pillar and Deiters' cells) using an inducible Cre line, Prox1-CreER(T2). Inactivation of Rb in these SCs results in cell cycle reentry of both pillar and Deiters' cells, and completion of cell division with an increase in cell number of pillar cells. Interestingly, nuclei of Rb(-/-) mitotic pillar and Deiters' cells migrate toward the HC layer and divide near the epithelial surface in a manner similar to the SCs in the regenerating avian auditory epithelium. In contrast to postmitotic Rb(-/-) HCs which abort cell division, postmitotic Rb(-/-) pillar cells can proliferate, maintain their SC fate and survive for more than a week. However, no newly formed HCs are detected and SC death followed by HC loss occurs. Our studies accomplish a crucial step toward functional HC regeneration in the mammalian cochlea in vivo, demonstrating the critical role of Rb in maintaining quiescence of postmitotic pillar and Deiters' cells and highlighting the heterogeneity between these two cell types. Therefore, the combination of transient Rb inactivation and further manipulation of transcription factors (i.e., Atoh1 activation) in SCs may represent an effective therapeutic avenue for HC regeneration in the mammalian cochlea.
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207
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Silbereis J, Heintz T, Taylor MM, Ganat Y, Ment LR, Bordey A, Vaccarino F. Astroglial cells in the external granular layer are precursors of cerebellar granule neurons in neonates. Mol Cell Neurosci 2010; 44:362-73. [PMID: 20470892 DOI: 10.1016/j.mcn.2010.05.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Revised: 04/17/2010] [Accepted: 05/03/2010] [Indexed: 12/12/2022] Open
Abstract
It is well established that cerebellar granule cell precursors (GCPs) initially derive from progenitors in the rhombic lip of the embryonic cerebellar primordium. GCPs proliferate and migrate tangentially across the cerebellum to form the external granule cell layer (EGL) in late embryogenesis and early postnatal development. It is unclear whether GCPs are specified exclusively in the embryonic rhombic lip or whether their precursor persists in the neonate. Using transgenic mice expressing DsRed under the human glial fibrillary acidic protein (hGFAP) promoter, we found 2 populations of DsRed(+) cells in the EGL in the first postnatal week defined by bright and faint DsRed-fluorescent signal. Bright DsRed(+) cells have a protein expression profile and electrophysiological characteristics typical of astrocytes, but faint DsRed(+) cells in the EGL and internal granule cell layer (IGL) express markers and physiological properties of immature neurons. To determine if these astroglial cells gave rise to GCPs, we genetically tagged them with EGFP or betagal reporter genes at postnatal day (P)3-P5 using a hGFAP promoter driven inducible Cre recombinase. We found that GFAP promoter(+) cells in the EGL are proliferative and express glial and neural stem cell markers. In addition, immature granule cells (GCs) en route to the IGL at P12 as well as GCs in the mature cerebellum, 30days after recombination, express the reporter protein, suggesting that GFAP promoter(+) cells in the EGL generate a subset of granule cells. The identification of glial cells which function as neuronal progenitor cells profoundly impacts our understanding of cellular plasticity in the developing cerebellum.
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Affiliation(s)
- John Silbereis
- Child Study Center, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA
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208
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Sedmera D. Factors in ventricular and atrioventricular valve growth: An embryologist's perspective. PROGRESS IN PEDIATRIC CARDIOLOGY 2010. [DOI: 10.1016/j.ppedcard.2010.02.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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209
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Nguyen CT, Langenbacher A, Hsieh M, Chen JN. The PAF1 complex component Leo1 is essential for cardiac and neural crest development in zebrafish. Dev Biol 2010; 341:167-75. [PMID: 20178782 DOI: 10.1016/j.ydbio.2010.02.020] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2009] [Revised: 02/08/2010] [Accepted: 02/15/2010] [Indexed: 10/19/2022]
Abstract
Leo1 is a component of the Polymerase-Associated Factor 1 (PAF1) complex, an evolutionarily conserved protein complex involved in gene transcription regulation and chromatin remodeling. The role of leo1 in vertebrate embryogenesis has not previously been examined. Here, we report that zebrafish leo1 encodes a nuclear protein that has a similar molecular structure to Leo1 proteins from other species. From a genetic screen, we identified a zebrafish mutant defective in the leo1 gene. The truncated Leo1(LA1186) protein lacks a nuclear localization signal and is distributed mostly in the cytoplasm. Phenotypic analysis showed that while the initial patterning of the primitive heart tube is not affected in leo1(LA1186) mutant embryos, the differentiation of cardiomyocytes at the atrioventricular boundary is aberrant, suggesting a requirement for Leo1 in cardiac differentiation. In addition, the expression levels of markers for neural crest-derived cells such as crestin, gch2, dct and mitfa are greatly reduced in leo1(LA1186) mutants, indicating a requirement for Leo1 in maintaining the neural crest population. Consistent with this finding, melanocyte and xanthophore populations are severely reduced, craniofacial cartilage is barely detectable, and mbp-positive glial cells are absent in leo1(LA1186) mutants after three days of development. Taken together, these results provide the first genetic evidence of the requirement for Leo1 in the development of the heart and neural crest cell populations.
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Affiliation(s)
- Catherine T Nguyen
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, CA 90095, USA
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210
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Reduced versican cleavage due to Adamts9 haploinsufficiency is associated with cardiac and aortic anomalies. Matrix Biol 2010; 29:304-16. [PMID: 20096780 DOI: 10.1016/j.matbio.2010.01.005] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Revised: 12/21/2009] [Accepted: 01/14/2010] [Indexed: 01/08/2023]
Abstract
Here, we demonstrate that ADAMTS9, a highly conserved versican-degrading protease, is required for correct cardiovascular development and adult homeostasis. Analysis of Adamts9(+/LacZ) adult mice revealed anomalies in the aortic wall, valvulosinus and valve leaflets. Abnormal myocardial projections and 'spongy' myocardium consistent with non-compaction of the left ventricle were also found in Adamts9(+/LacZ) mice. During development, Adamts9 was expressed in derivatives of the Secondary Heart Field, vascular smooth muscle cells in the arterial wall, mesenchymal cells of the valves, and non-myocardial cells of the ventricles, but expression also continued in the adult heart and ascending aorta. Thus, the adult cardiovascular anomalies found in Adamts9(+/LacZ) hearts could result from subtle developmental alterations in extracellular matrix remodeling or defects in adult homeostasis. The valvular and aortic anomalies of Adamts9(+/LacZ) hearts were associated with accumulation of versican and a decrease in cleaved versican relative to WT littermates. These data suggest a potentially important role for ADAMTS9 cleavage of versican, or other, as yet undefined substrates in development and allostasis of cardiovascular extracellular matrix. In addition, these studies identify ADAMTS9 as a potential candidate gene for congenital cardiac anomalies. Mouse models of ADAMTS9 deficiency may be useful to study myxomatous valve degeneration.
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211
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Peacock JD, Levay AK, Gillaspie DB, Tao G, Lincoln J. Reduced sox9 function promotes heart valve calcification phenotypes in vivo. Circ Res 2010; 106:712-9. [PMID: 20056916 DOI: 10.1161/circresaha.109.213702] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
RATIONALE Calcification of heart valve structures is the most common form of valvular disease and is characterized by the appearance of bone-like phenotypes within affected structures. Despite the clinical significance, the underlying etiology of disease onset and progression is largely unknown and valve replacement remains the most effective treatment. The SRY-related transcription factor Sox9 is expressed in developing and mature heart valves, and its function is required for expression of cartilage-associated proteins, similar to its role in chondrogenesis. In addition to cartilage-associated defects, mice with reduced sox9 function develop skeletal bone prematurely; however, the ability of sox9 deficiency to promote ectopic osteogenic phenotypes in heart valves has not been examined. OBJECTIVE This study aims to determine the role of Sox9 in maintaining connective tissue homeostasis in mature heart valves using in vivo and in vitro approaches. METHODS AND RESULTS Using histological and molecular analyses, we report that, from 3 months of age, Sox9(fl/+);Col2a1-cre mice develop calcific lesions in heart valve leaflets associated with increased expression of bone-related genes and activation of inflammation and matrix remodeling processes. Consistently, ectopic calcification is also observed following direct knockdown of Sox9 in heart valves in vitro. Furthermore, we show that retinoic acid treatment in mature heart valves is sufficient to promote calcific processes in vitro, which can be attenuated by Sox9 overexpression. CONCLUSIONS This study provides insight into the molecular mechanisms of heart valve calcification and identifies reduced Sox9 function as a potential genetic basis for calcific valvular disease.
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Affiliation(s)
- Jacqueline D Peacock
- Department of Molecular and Cellular Pharmacology, Leonard M. Miller School of Medicine, University of Miami, 1600 NW 10th Ave., Miami, FL 33136, USA
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212
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Watanabe Y, Miyagawa-Tomita S, Vincent SD, Kelly RG, Moon AM, Buckingham ME. Role of mesodermal FGF8 and FGF10 overlaps in the development of the arterial pole of the heart and pharyngeal arch arteries. Circ Res 2009; 106:495-503. [PMID: 20035084 DOI: 10.1161/circresaha.109.201665] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
RATIONALE The genes encoding fibroblast growth factor (FGF) 8 and 10 are expressed in the anterior part of the second heart field that constitutes a population of cardiac progenitor cells contributing to the arterial pole of the heart. Previous studies of hypomorphic and conditional Fgf8 mutants show disrupted outflow tract (OFT) and right ventricle (RV) development, whereas Fgf10 mutants do not have detectable OFT defects. OBJECTIVES Our aim was to investigate functional overlap between Fgf8 and Fgf10 during formation of the arterial pole. METHODS AND RESULTS We generated mesodermal Fgf8; Fgf10 compound mutants with MesP1Cre. The OFT/RV morphology in these mutants was affected with variable penetrance; however, the incidence of embryos with severely affected OFT/RV morphology was significantly increased in response to decreasing Fgf8 and Fgf10 gene dosage. Fgf8 expression in the pharyngeal arch ectoderm is important for development of the pharyngeal arch arteries and their derivatives. We now show that Fgf8 deletion in the mesoderm alone leads to pharyngeal arch artery phenotypes and that these vascular phenotypes are exacerbated by loss of Fgf10 function in the mesodermal core of the arches. CONCLUSIONS These results show functional overlap of FGF8 and FGF10 signaling from second heart field mesoderm during development of the OFT/RV, and from pharyngeal arch mesoderm during pharyngeal arch artery formation, highlighting the sensitivity of these key aspects of cardiovascular development to FGF dosage.
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Affiliation(s)
- Yusuke Watanabe
- Department of Developmental Biology, URA CNRS 2578, Institut Pasteur, 25 rue du Dr. Roux 75015 Paris, France
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213
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Liao WP, Uetzmann L, Burtscher I, Lickert H. Generation of a mouse line expressing Sox17-driven Cre recombinase with specific activity in arteries. Genesis 2009; 47:476-83. [PMID: 19415628 DOI: 10.1002/dvg.20520] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The HMG-box transcription factor Sox17 has been shown to play important roles in both endoderm formation and cardiovascular development. To conditionally inactivate genes in these domains, we have targeted a codon improved Cre Recombinase (iCre) into exon 1 of the Sox17 gene. Surprisingly, Cre-mediated recombination in the Rosa26 reporter mouse line revealed largely specific activity within the vasculature rather than in endoderm-derived tissues. Here we report a new Cre knock-in mouse line, Sox17(iCre) with activity in the vascular endothelial cells of arteries in the cardiovascular system but not in veins. Cre-mediated recombination was also strongly detected in the liver and spleen, the two organs associated with hematopoiesis. Thus, these results indicate that the Sox17(iCre) would be an appropriate tool for conditional mutagenesis of genes in the vasculature and could be used in studies of blood vessel development and angiogenesis. Additionally, we provide evidence that two different promoters drive Sox17 expression in the endodermal and vascular system.
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Affiliation(s)
- W Perry Liao
- Helmholtz Zentrum München, Institute of Stem Cell Research, Neuherberg, Germany
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214
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Varadkar PA, Kraman M, McCright B. Generation of mice that conditionally express the activation domain of Notch2. Genesis 2009; 47:573-8. [PMID: 19530136 DOI: 10.1002/dvg.20537] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The Notch pathway is an intercellular signaling mechanism frequently used for controlling cell fate during organogenesis. There are four structurally related Notch receptors in mice and humans, and Notch1 and Notch2 are essential genes. In this report we describe the construction of a transgenic mouse strain that expresses the Notch2 intracellular domain in response to cell lineage specific expression of Cre recombinase. This approach bypasses the requirement for ligand- receptor interaction and allows the direct determination of the consequences of Notch2 activation in vivo. Exogenous expression of the Notch2 intracellular domain resulted in the developmental arrest of secondary heart field derived cardiomyocytes during the transition from immature alpha-Smooth Muscle Actin expressing cells to mature alpha-Actinin positive cardiomyocytes. In contrast, a cell nonautonomous mesenchymal expansion was observed in semilunar valves. This new conditionally expressed allele of Notch2 can be used in studies by investigators interested in the effects of Notch2 activation in vivo.
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215
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Levin MD, Lu MM, Petrenko NB, Hawkins BJ, Gupta TH, Lang D, Buckley PT, Jochems J, Liu F, Spurney CF, Yuan LJ, Jacobson JT, Brown CB, Huang L, Beermann F, Margulies KB, Madesh M, Eberwine JH, Epstein JA, Patel VV. Melanocyte-like cells in the heart and pulmonary veins contribute to atrial arrhythmia triggers. J Clin Invest 2009; 119:3420-36. [PMID: 19855129 DOI: 10.1172/jci39109] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Accepted: 08/25/2009] [Indexed: 01/27/2023] Open
Abstract
Atrial fibrillation is the most common clinical cardiac arrhythmia. It is often initiated by ectopic beats arising from the pulmonary veins and atrium, but the source and mechanism of these beats remains unclear. The melanin synthesis enzyme dopachrome tautomerase (DCT) is involved in intracellular calcium and reactive species regulation in melanocytes. Given that dysregulation of intracellular calcium and reactive species has been described in patients with atrial fibrillation, we investigated the role of DCT in this process. Here, we characterize a unique DCT-expressing cell population within murine and human hearts that populated the pulmonary veins, atria, and atrioventricular canal. Expression profiling demonstrated that this population expressed adrenergic and muscarinic receptors and displayed transcriptional profiles distinct from dermal melanocytes. Adult mice lacking DCT displayed normal cardiac development but an increased susceptibility to atrial arrhythmias. Cultured primary cardiac melanocyte-like cells were excitable, and those lacking DCT displayed prolonged repolarization with early afterdepolarizations. Furthermore, mice with mutations in the tyrosine kinase receptor Kit lacked cardiac melanocyte-like cells and did not develop atrial arrhythmias in the absence of DCT. These data suggest that dysfunction of melanocyte-like cells in the atrium and pulmonary veins may contribute to atrial arrhythmias.
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Affiliation(s)
- Mark D Levin
- Penn Cardiovascular Institute and University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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216
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Waclaw RR, Wang B, Pei Z, Ehrman LA, Campbell K. Distinct temporal requirements for the homeobox gene Gsx2 in specifying striatal and olfactory bulb neuronal fates. Neuron 2009; 63:451-65. [PMID: 19709628 DOI: 10.1016/j.neuron.2009.07.015] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2009] [Revised: 06/16/2009] [Accepted: 07/16/2009] [Indexed: 11/15/2022]
Abstract
The homeobox gene Gsx2 (formerly Gsh2) is known to be required for striatal and olfactory bulb neurogenesis; however, its specific role in the specification of these two neuronal subtypes remains unclear. To address this, we have employed a temporally regulated gain-of-function approach in transgenic mice and found that misexpression of Gsx2 at early stages of telencephalic neurogenesis favors the specification of striatal projection neuron identity over that of olfactory bulb interneurons. In contrast, delayed activation of the Gsx2 transgene until later stages exclusively promotes olfactory bulb interneuron identity. In a complementary approach, we have conditionally inactivated Gsx2 in a temporally progressive manner. Unlike germline Gsx2 mutants, which exhibit severe alterations in both striatal and olfactory bulb neurogenesis at birth, the conditional mutants exhibited defects restricted to olfactory bulb interneurons. These results demonstrate that Gsx2 specifies striatal projection neuron and olfactory bulb interneuron identity at distinct time points during telencephalic neurogenesis.
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Affiliation(s)
- Ronald R Waclaw
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
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217
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Abstract
In recent years, significant advances have been made in the definition of regulatory pathways that control normal and abnormal cardiac valve development. Here, we review the cellular and molecular mechanisms underlying the early development of valve progenitors and establishment of normal valve structure and function. Regulatory hierarchies consisting of a variety of signaling pathways, transcription factors, and downstream structural genes are conserved during vertebrate valvulogenesis. Complex intersecting regulatory pathways are required for endocardial cushion formation, valve progenitor cell proliferation, valve cell lineage development, and establishment of extracellular matrix compartments in the stratified valve leaflets. There is increasing evidence that the regulatory mechanisms governing normal valve development also contribute to human valve pathology. In addition, congenital valve malformations are predominant among diseased valves replaced late in life. The understanding of valve developmental mechanisms has important implications in the diagnosis and management of congenital and adult valve disease.
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Affiliation(s)
- Michelle D Combs
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center ML7020, 240 Albert Sabin Way, Cincinnati, OH 45229, USA
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218
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Nomura-Kitabayashi A, Phoon CKL, Kishigami S, Rosenthal J, Yamauchi Y, Abe K, Yamamura KI, Samtani R, Lo CW, Mishina Y. Outflow tract cushions perform a critical valve-like function in the early embryonic heart requiring BMPRIA-mediated signaling in cardiac neural crest. Am J Physiol Heart Circ Physiol 2009; 297:H1617-28. [PMID: 19717734 DOI: 10.1152/ajpheart.00304.2009] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Neural crest-specific ablation of BMP type IA receptor (BMPRIA) causes embryonic lethality by embryonic day (E) 12.5, and this was previously postulated to arise from a myocardial defect related to signaling by a small population of cardiac neural crest cells (cNCC) in the epicardium. However, as BMP signaling via cNCC is also required for proper development of the outflow tract cushions, precursors to the semilunar valves, a plausible alternate or additional hypothesis is that heart failure may result from an outflow tract cushion defect. To investigate whether the outflow tract cushions may serve as dynamic valves in regulating hemodynamic function in the early embryo, in this study we used noninvasive ultrasound biomicroscopy-Doppler imaging to quantitatively assess hemodynamic function in mouse embryos with P0-Cre transgene mediated neural crest ablation of Bmpr1a (P0 mutants). Similar to previous studies, the neural crest-deleted Bmpr1a P0 mutants died at approximately E12.5, exhibiting persistent truncus arteriosus, thinned myocardium, and congestive heart failure. Surprisingly, our ultrasound analyses showed normal contractile indices, heart rate, and atrioventricular conduction in the P0 mutants. However, reversed diastolic arterial blood flow was detected as early as E11.5, with cardiovascular insufficiency and death rapidly ensuing by E12.5. Quantitative computed tomography showed thinning of the outflow cushions, and this was associated with a marked reduction in cell proliferation. These results suggest BMP signaling to cNCC is required for growth of the outflow tract cushions. This study provides definitive evidence that the outflow cushions perform a valve-like function critical for survival of the early mouse embryo.
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Affiliation(s)
- Aya Nomura-Kitabayashi
- Laboratory of Reproductive and Developmental Toxicology, National Institutes of Environmental Health Science, National Institutes of Health, Research Triangle Park, North Carolina, USA
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219
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GATA6 mutations cause human cardiac outflow tract defects by disrupting semaphorin-plexin signaling. Proc Natl Acad Sci U S A 2009; 106:13933-8. [PMID: 19666519 DOI: 10.1073/pnas.0904744106] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Congenital heart diseases (CHD) occur in nearly 1% of all live births and are the major cause of infant mortality and morbidity. Although an improved understanding of the genetic causes of CHD would provide insight into the underlying pathobiology, the genetic etiology of most CHD remains unknown. Here we show that mutations in the gene encoding the transcription factor GATA6 cause CHD characteristic of a severe form of cardiac outflow tract (OFT) defect, namely persistent truncus arteriosus (PTA). Two different GATA6 mutations were identified by systematic genetic analysis using DNA from patients with PTA. Genes encoding the neurovascular guiding molecule semaphorin 3C (SEMA3C) and its receptor plexin A2 (PLXNA2) appear to be regulated directly by GATA6, and both GATA6 mutant proteins failed to transactivate these genes. Transgenic analysis further suggests that, in the developing heart, the expression of SEMA3C in the OFT/subpulmonary myocardium and PLXNA2 in the cardiac neural crest contributing to the OFT is dependent on GATA transcription factors. Together, our data implicate mutations in GATA6 as genetic causes of CHD involving OFT development, as a result of the disruption of the direct regulation of semaphorin-plexin signaling.
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220
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Silbereis J, Cheng E, Ganat YM, Ment LR, Vaccarino FM. Precursors with glial fibrillary acidic protein promoter activity transiently generate GABA interneurons in the postnatal cerebellum. Stem Cells 2009; 27:1152-63. [PMID: 19418461 DOI: 10.1002/stem.18] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Neural stem or progenitor cells (NSC/NPCs) able to generate the different neuron and glial cell types of the cerebellum have been isolated in vitro, but their identity and location in the intact cerebellum are unclear. Here, we use inducible Cre recombination in GFAPCreER(T2) mice to irreversibly activate reporter gene expression at P2 (postnatal day 2), P5, and P12 in cells with GFAP (glial fibrillary acidic protein) promoter activity and analyze the fate of genetically tagged cells in vivo. We show that cells tagged at P2-P5 with beta-galactosidase or enhanced green fluorescent proteins reporter genes generate at least 30% of basket and stellate GABAergic interneurons in the molecular layer (ML) and that they lose their neurogenic potential by P12, after which they generate only glia. Tagged cells in the cerebellar white matter (WM) were initially GFAP/S100beta+ and expressed the NSC/NPCs proteins LeX, Musashi1, and Sox2 in vivo. One week after tagging, reporter+ cells in the WM upregulated the neuronal progenitor markers Mash1, Pax2, and Gad-67. These Pax2+ progenitors migrated throughout the cerebellar cortex, populating the ML and leaving the WM by P18. These data suggest that a pool of GFAP/S100beta+ glial cells located in the cerebellar WM generate a large fraction of cerebellar interneurons for the ML within the first postnatal 12 days of cerebellar development. This restricted critical period implies that powerful inhibitory factors may restrict their fate potential in vivo at later stages of development.
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Affiliation(s)
- John Silbereis
- Child Study Center, Yale University School of Medicine, New Haven, CT 06520, USA
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221
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Balani K, Brito FC, Kos L, Agarwal A. Melanocyte pigmentation stiffens murine cardiac tricuspid valve leaflet. J R Soc Interface 2009; 6:1097-102. [PMID: 19586956 DOI: 10.1098/rsif.2009.0174] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Pigmentation of murine cardiac tricuspid valve leaflet is associated with melanocyte concentration, which affects its stiffness. Owing to its biological and viscoelastic nature, estimation of the in situ stiffness measurement becomes a challenging task. Therefore, quasi-static and nanodynamic mechanical analysis of the leaflets of the mouse tricuspid valve is performed in the current work. The mechanical properties along the leaflet vary with the degree of pigmentation. Pigmented regions of the valve leaflet that contain melanocytes displayed higher storage modulus (7-10 GPa) than non-pigmented areas (2.5-4 GPa). These results suggest that the presence of melanocytes affects the viscoelastic properties of the mouse atrioventricular valves and are important for their proper functioning in the organism.
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Affiliation(s)
- Kantesh Balani
- Materials and Metallurgical Engineering, Indian Institute of Technology Kanpur, Kanpur, India.
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222
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Boudoulas KD, Hatzopoulos AK. Cardiac repair and regeneration: the Rubik's cube of cell therapy for heart disease. Dis Model Mech 2009; 2:344-58. [PMID: 19553696 PMCID: PMC2707103 DOI: 10.1242/dmm.000240] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Acute ischemic injury and chronic cardiomyopathies damage healthy heart tissue. Dead cells are gradually replaced by a fibrotic scar, which disrupts the normal electromechanical continuum of the ventricular muscle and compromises its pumping capacity. Recent studies in animal models of ischemic cardiomyopathy suggest that transplantation of various stem cell preparations can improve heart recovery after injury. The first clinical trials in patients produced some encouraging results, showing modest benefits. Most of the positive effects are probably because of a favorable paracrine influence of stem cells on the disease microenvironment. Stem cell therapy attenuates inflammation, reduces apoptosis of surrounding cells, induces angiogenesis, and lessens the extent of fibrosis. However, little new heart tissue is formed. The current challenge is to find ways to improve the engraftment, long-term survival and appropriate differentiation of transplanted stem cells within the cardiovascular tissue. Hence, there has been a surge of interest in pluripotent stem cells with robust cardiogenic potential, as well as in the inherent repair and regenerative mechanisms of the heart. Recent discoveries on the biology of adult stem cells could have relevance for cardiac regeneration. Here, we discuss current developments in the field of cardiac repair and regeneration, and present our ideas about the future of stem cell therapy.
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Affiliation(s)
- Konstantinos D. Boudoulas
- Vanderbilt University, Department of Medicine and Department of Cell and Developmental Biology, Division of Cardiovascular Medicine, Nashville, TN 37232, USA
- Johns Hopkins University School of Medicine, Department of Medicine, Division of Cardiology, Baltimore, MD 21205, USA
| | - Antonis K. Hatzopoulos
- Vanderbilt University, Department of Medicine and Department of Cell and Developmental Biology, Division of Cardiovascular Medicine, Nashville, TN 37232, USA
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223
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Protein tyrosine phosphatase activity in the neural crest is essential for normal heart and skull development. Proc Natl Acad Sci U S A 2009; 106:11270-5. [PMID: 19541608 DOI: 10.1073/pnas.0902230106] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Mutations within the protein tyrosine phosphatase, SHP2, which is encoded by PTPN11, cause a significant proportion of Noonan syndrome (NS) cases, typically presenting with both cardiac disease and craniofacial abnormalities. Neural crest cells (NCCs) participate in both heart and skull formation, but the role of SHP2 signaling in NCC has not yet been determined. To gain insight into the role of SHP2 in NCC function, we ablated PTPN11 specifically in premigratory NCCs. SHP2-deficient NCCs initially exhibited normal migratory and proliferative patterns, but in the developing heart failed to migrate into the developing outflow tract. The embryos displayed persistent truncus arteriosus and abnormalities of the great vessels. The craniofacial deficits were even more pronounced, with large portions of the face and cranium affected, including the mandible and frontal and nasal bones. The data show that SHP2 activity in the NCC is essential for normal migration and differentiation into the diverse lineages found in the heart and skull and demonstrate the importance of NCC-based normal SHP2 activity in both heart and skull development, providing insight into the syndromic presentation characteristic of NS.
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224
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Nagao M, Campbell K, Burns K, Kuan CY, Trumpp A, Nakafuku M. Coordinated control of self-renewal and differentiation of neural stem cells by Myc and the p19ARF-p53 pathway. ACTA ACUST UNITED AC 2009; 183:1243-57. [PMID: 19114593 PMCID: PMC2606961 DOI: 10.1083/jcb.200807130] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The modes of proliferation and differentiation of neural stem cells (NSCs) are coordinately controlled during development, but the underlying mechanisms remain largely unknown. In this study, we show that the protooncoprotein Myc and the tumor suppressor p19(ARF) regulate both NSC self-renewal and their neuronal and glial fate in a developmental stage-dependent manner. Early-stage NSCs have low p19(ARF) expression and retain a high self-renewal and neurogenic capacity, whereas late-stage NSCs with higher p19(ARF) expression possess a lower self-renewal capacity and predominantly generate glia. Overexpression of Myc or inactivation of p19(ARF) reverts the properties of late-stage NSCs to those of early-stage cells. Conversely, inactivation of Myc or forced p19(ARF) expression attenuates self-renewal and induces precocious gliogenesis through modulation of the responsiveness to gliogenic signals. These actions of p19(ARF) in NSCs are mainly mediated by p53. We propose that opposing actions of Myc and the p19(ARF)-p53 pathway have important functions in coordinated developmental control of self-renewal and cell fate choices in NSCs.
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Affiliation(s)
- Motoshi Nagao
- Division of Developmental Biology, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH 45229, USA
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225
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Orlandi A, Hao H, Ferlosio A, Clément S, Hirota S, Spagnoli LG, Gabbiani G, Chaponnier C. Alpha actin isoforms expression in human and rat adult cardiac conduction system. Differentiation 2009; 77:360-8. [PMID: 19281784 DOI: 10.1016/j.diff.2008.12.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Revised: 12/16/2008] [Accepted: 12/18/2008] [Indexed: 11/26/2022]
Abstract
In the adult heart, cardiac muscle comprises the working myocardium and the conduction system (CS). The latter includes the sinoatrial node (SAN), the internodal tract or bundle (IB), the atrioventricular node (AVN), the atrioventricular bundle (AVB), the bundle branches (BB) and the peripheral Purkinje fibers (PF). Most of the information concerning the phenotypic features of CS tissue derives from the characterization of avian and rodent developing hearts; data concerning the expression of actin isoforms in adult CS cardiomyocytes are scarce. Using specific antibodies, we investigated the distribution of alpha-skeletal (alpha-SKA), alpha-cardiac (alpha-CA), alpha-smooth muscle (alpha-SMA) actin isoforms and other muscle-typical proteins in the CS of human and rat hearts at different ages. SAN and IB cardiomyocytes were characterized by the presence of alpha-SMA, alpha-CA, calponin and caldesmon, whereas alpha-SKA and vimentin were absent. Double immunofluorescence demonstrated the co-localisation of alpha-SMA and alpha-CA in I-bands of SAN cardiomyocytes. AVN, AVB, BB and PF cardiomyocytes were alpha-SMA, calponin, caldesmon and vimentin negative, and alpha-CA and alpha-SKA positive. No substantial differences in actin isoform distribution were observed in human and rat hearts, except for the presence of isolated subendocardial alpha-SMA positive cardiomyocytes co-expressing alpha-CA in the ventricular septum of the rat. Aging did not influence CS cardiomyocyte actin isoform expression profile. These findings support the concept that cardiomyocytes of SAN retain the phenotype of a developing myogenic cell throughout the entire life span.
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Affiliation(s)
- Augusto Orlandi
- Institute of Anatomic Pathology, Department of Biopathology and Image Diagnostics, Tor Vergata University of Rome-PTV, Via Montpellier 1, 00133, Rome, Italy.
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226
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Abstract
The mammalian brain contains a population of neurons that are continuously generated from late embryogenesis through adulthood-after the generation of almost all other neuronal types. This brain region-the hippocampal dentate gyrus-is in a sense, therefore, persistently immature. Postnatal and adult neurogenesis is likely an essential feature of the dentate, which is critical for learning and memory. Protracted neurogenesis after birth would allow the new cells to develop in conjunction with external events-but it may come with a price: while neurogenesis in utero occurs in a protected environment, children and adults are exposed to any number of hazards, such as toxins and infectious agents. Mature neurons might be resistant to such exposures, but new neurons may be vulnerable. Consistent with this prediction, in adult rodents seizures disrupt the integration of newly generated granule cells, whereas mature granule cells are comparatively unaffected. Significantly, abnormally interconnected cells may contribute to epileptogenesis and/or associated cognitive and memory deficits. Finally, studies increasingly indicate that new granule cells are extremely sensitive to a host of endogenous and exogenous factors, raising the possibility that disrupted granule cell integration may be a common feature of many neurological diseases.
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Affiliation(s)
- Steve C Danzer
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio.
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227
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Hor KN, Border WL, Cripe LH, Benson DW, Hinton RB. The presence of bicuspid aortic valve does not predict ventricular septal defect type. Am J Med Genet A 2009; 146A:3202-5. [PMID: 19012349 DOI: 10.1002/ajmg.a.32609] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Previous studies have identified an increased incidence of bicuspid aortic valve (BAV) in patients with ventricular septal defect (VSD). Because endocardial cushion remodeling contributes to both the formation of semilunar valves and ventricular septation, we hypothesized that examination of humans with BAV and VSD would identify a specific VSD type. We evaluated VSD type in pediatric patients diagnosed with BAV and VSD (n=82) and compared findings to patients diagnosed with VSD and normal aortic valve morphology (n=429). VSD type was described as conoventricular, muscular, inlet or conoseptal using a clinical taxonomy. Based on the contribution of the outflow tract endocardial cushions to the membranous ventricular septum, we expected patients with BAV to have conoventricular VSD. In both patient groups, conoventricular VSD was most common; however, the prevalence was not significantly different when BAV patients were compared to those with normal aortic valve morphology (67% vs. 57%, P=0.11). The primary finding of this study is that despite a developmental link between semilunar valve formation and ventricular septation during cardiogenesis, there is no clear association between BAV and VSD type. This may be due to phenotypic and genetic heterogeneity of BAV and VSD, other modifying factors as manifested by differences in associated CVM, as well as limitations of the clinical taxonomy of VSD.
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Affiliation(s)
- Kan N Hor
- Division of Cardiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA
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228
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Abstract
The pulmonary circulation represents a unique vascular bed, receiving 100% of the cardiac output while maintaining low blood pressure. Multiple different cell types, including endothelium, smooth muscle, and fibroblasts, contribute to normal vascular function, and to the vascular response to injury. Our understanding of the basic cell biology of these various cell types, and the roles they play in vascular homeostasis and disease, remains quite limited despite several decades of study. Recent advances in approaches that enable the mapping of cell origin and the study of the molecular basis of structure and function have resulted in a rapid accumulation of new information that is essential to vascular biology. A recent National Institutes of Health workshop was held to discuss emerging concepts in lung vascular biology. The findings of this workshop are summarized in this article.
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229
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Lack of Gata3 results in conotruncal heart anomalies in mouse. Mech Dev 2009; 126:80-9. [DOI: 10.1016/j.mod.2008.10.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2006] [Revised: 09/10/2008] [Accepted: 10/06/2008] [Indexed: 10/21/2022]
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230
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Abstract
The development of the embryonic heart is dependent upon the generation and incorporation of different mesenchymal subpopulations that derive from intra- and extra-cardiac sources, including the endocardium, epicardium, neural crest, and second heart field. Each of these populations plays a crucial role in cardiovascular development, in particular in the formation of the valvuloseptal apparatus. Notwithstanding shared mechanisms by which these cells are generated, their fate and function differ profoundly by their originating source. While most of our early insights into the origin and fate of the cardiac mesenchyme has come from experimental studies in avian model systems, recent advances in transgenic mouse technology has enhanced our ability to study these cell populations in the mammalian heart. In this article, we will review the current understanding of the role of cardiac mesenchyme in cardiac morphogenesis and discuss several new paradigms based on recent studies in the mouse.
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Affiliation(s)
- Brian S Snarr
- Department of Cell Biology and Anatomy, Medical University of South Carolina, Charleston, South Carolina 29425, USA
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231
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Tateishi K, Takehara N, Matsubara H, Oh H. Stemming heart failure with cardiac- or reprogrammed-stem cells. J Cell Mol Med 2008; 12:2217-32. [PMID: 18754813 PMCID: PMC4514101 DOI: 10.1111/j.1582-4934.2008.00487.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Despite extensive efforts to control myocyte growth by genetic targeting of the cell cycle machinery and small molecules for cardiac repair, adult myocytes themselves appeared to divide a limited number of times in response to a variety of cardiac muscle stresses. Rare tissue-resident stem cells are thought to exist in many adult organs that are capable of self-renewal and differentiation and possess a range of actions that are potentially therapeutic. Recent studies suggest that a population of cardiac stem cells (CSCs) is maintained after cardiac development in the adult heart in mammals including human beings; however, homeostatic cardiomyocyte replacement might be stem cell-dependent, and functional myocardial regeneration after cardiac muscle damage is not yet considered as sufficient to fully maintain or reconstitute the cardiovascular system and function. Although it is clear that adult CSCs have limitations in their capabilities to proliferate extensively and differentiate in response to injury in vivo for replenishing mature car-diomyocytes and potentially function as resident stem cells. Transplantation of CSCs expanded ex vivo seems to require an integrated strategy of cell growth-enhancing factor(s) and tissue engineering technologies to support the donor cell survival and subsequent proliferation and differentiation in the host microenvironment. There has been substantial interest regarding the evidence that mammalian fibroblasts can be genetically reprogrammed to induced pluripotent stem (iPS) cells, which closely resemble embryonic stem (ES) cell properties capable of differentiating into functional cardiomyocytes, and these cells may provide an alternative cell source for generating patient-specific CSCs for therapeutic applications.
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Affiliation(s)
- Kento Tateishi
- Department of Experimental Therapeutics, Translational Research Center, Kyoto University Hospital, and Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto, Japan
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232
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Chen J, Han M, Manisastry SM, Trotta P, Serrano MC, Huhta JC, Linask KK. Molecular effects of lithium exposure during mouse and chick gastrulation and subsequent valve dysmorphogenesis. ACTA ACUST UNITED AC 2008; 82:508-18. [PMID: 18418887 DOI: 10.1002/bdra.20448] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Lithium (Li) has been associated with cardiac teratogenicity in the developing fetus. We took advantage of the association of therapeutic administration of Li with an increase in heart defects to gain insight into both normal and pathological heart and valve development with GSK-3 inhibition. The objective of this study was to define whether Li mimicry of canonical Wnt/beta-catenin signaling induces cardiac valve defects. METHODS Li was administered by a single intraperitoneal injection to the pregnant mouse on embryonic day E6.75, much earlier than heretofore analyzed. On E15.5 developing heart defects were defined by Doppler ultrasound. The embryonic hearts were analyzed for changes in patterning of active canonical Wnt expression and nuclear factor of the activated T cells-c1 (NFATc1), both key regulators of valve development. Li-exposed chick embryos were used to define the early cell populations during gastrulation that are susceptible to GSK-3 inhibition and may relate to valve formation. RESULTS Li exposure during gastrulation decreased the number of prechordal plate (PP) cells that reached the anterior intestinal portal, a region associated with valve development. Li decreased expression of Hex, an endoderm cardiac inducing molecule, normally also expressed by the PP cells, and of Sox 4 at the anterior intestinal portal and NFAT, critical factors in valvulogenesis. CONCLUSIONS Cells existing already during gastrulation are associated with valve formation days later. The Wnt/beta-catenin signaling in PP cells is normally repressed by Wnt antagonists and Hex is up-regulated. The antagonism occurring at the receptor level is bypassed by Li exposure by its intracellular inactivation of GSK-3 directly to augment Wnt signaling.
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Affiliation(s)
- Jizhen Chen
- USF - Pediatric Cardiology, Department of Pediatrics, Children's Research Institute, St. Petersburg, Florida 33701, USA
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233
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The rat heart contains a neural stem cell population; role in sympathetic sprouting and angiogenesis. J Mol Cell Cardiol 2008; 45:694-702. [PMID: 18718475 DOI: 10.1016/j.yjmcc.2008.07.013] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2008] [Revised: 07/18/2008] [Accepted: 07/21/2008] [Indexed: 12/26/2022]
Abstract
Nestin-expressing cells were identified in the normal rat heart characterized by a small cell body and numerous processes and following an ischemic insult migrated to the infarct region. The present study was undertaken to identify the phenotype, origin and biological role of nestin-expressing cells during reparative fibrosis. A neural stem cell phenotype was identified based on musashi-1 expression, growth as a neurosphere, and differentiation to a neuronal cell. Using the Wnt1-cre; Z/EG transgenic mouse model, which expresses EGFP in embryologically-derived neural crest cells, the reporter signal was detected in nestin-expressing cells residing in the heart. In infarcted human hearts, nestin-expressing cells were detected in the viable myocardium and the scar and morphologically analogous to the population identified in the rat heart. Following either an ischemic insult or the acute administration of 6-hydroxydopamine, sympathetic sprouting was dependent on the physical association of neurofilament-M immunoreactive fibres with nestin-positive processes emanating from neural stem cells. To specifically study the biological role of the subpopulation in the infarct region, neural stem cells were isolated from the scar, fluorescently labelled and transplanted in the heart of 3-day post-MI rats. Injected scar-derived neural stem cells migrated to the infarct region and were used as a substrate for de novo blood vessel formation. These data have demonstrated that the heart contains a resident population of neural stem cells derived from the neural crest and participate in reparative fibrosis. Their manipulation could provide an alternative approach to ameliorate the healing process following ischemic injury.
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234
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Genetic approaches for changing the heart and dissecting complex syndromes. J Mol Cell Cardiol 2008; 45:148-55. [PMID: 18601931 DOI: 10.1016/j.yjmcc.2008.06.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2008] [Revised: 05/21/2008] [Accepted: 06/03/2008] [Indexed: 01/18/2023]
Abstract
The genetic, biochemical and molecular bases of human cardiac disease have been the focus of extensive research efforts for many years. Early animal models of cardiovascular disease used pharmacologic or surgical interventions, or took advantage of naturally occurring genetic abnormalities and the data obtained were largely correlative. The inability to directly alter an organism's genetic makeup and cellular protein content and accurately measure the results of that manipulation precluded rigorous examination of true cause-effect and structure-function relationships. Directed genetic manipulation in the mouse gave researchers the ability to modify and control the mammalian heart's protein content, resulting in the rational design of models that could provide critical links between the mutated or absent protein and disease. Two techniques that have proven particularly useful are transgenesis, which involves the random insertion of ectopic genetic material of interest into a "host" genome, and gene targeting, which utilizes homologous recombination at a pre-selected locus. Initially, transgenesis and gene targeting were used to examine systemic loss-of-function and gain-of-function, respectively, but further refinements in both techniques have allowed for investigations of organ-specific, cell type-specific, developmental stage-sensitive and dose-dependent effects. Genetically engineered animal models of pediatric and adult cardiac disease have proven that, when used appropriately, these tools have the power to extend mere observation to the establishment of true causative proof. We illustrate the power of the general approach by showing how genetically engineered mouse models can define the precise signaling pathways that are affected by the gain-of-function mutation that underlies Noonan syndrome. Increasingly precise and modifiable animal models of human cardiac disease will allow researchers to determine not only pathogenesis, but also guide treatment and the development of novel therapies.
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235
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Porras D, Brown CB. Temporal-spatial ablation of neural crest in the mouse results in cardiovascular defects. Dev Dyn 2008; 237:153-62. [PMID: 18058916 DOI: 10.1002/dvdy.21382] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Neural crest cells are thought to play a critical role in human conotruncal morphogenesis and dysmorphogenesis. Much of our understanding of the contribution of neural crest to cardiovascular patterning comes from ablation and transplantation experiments in avian species. Although fate mapping experiments in mice suggests a conservation of function, the functional requirement for neural crest in cardiovascular development in mammals has not been formally tested. We used a novel two component genetic system for the temporal-spatial ablation of neural crest in the mouse. Affected embryos displayed a spectrum of cardiovascular outflow tract defects and aortic arch patterning abnormalities. We show that the severity of the cardiovascular phenotype is directly related to the level and extent of neural crest ablation. This is the first report of cardiac neural crest ablation in mammals, and it provides important insight into the role of the mammalian neural crest during cardiovascular development.
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Affiliation(s)
- Diego Porras
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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236
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Lopez V, Keen CL, Lanoue L. Prenatal zinc deficiency: influence on heart morphology and distribution of key heart proteins in a rat model. Biol Trace Elem Res 2008; 122:238-55. [PMID: 18224284 DOI: 10.1007/s12011-007-8079-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2007] [Revised: 10/25/2007] [Accepted: 11/23/2007] [Indexed: 12/22/2022]
Abstract
The etiology of congenital heart disease is multifactorial, with genetics and nutritional deficiencies recognized as causative agents. Maternal zinc (Zn) deficiency is associated with an increased risk for fetal heart malformations; however, the contributing mechanisms have yet to be identified. In this study, we fed pregnant rats a Zn-adequate diet (ZnA), a Zn-deficient (ZnD), or a restricted amount of Zn adequate diet (RF) beginning on gestation day (GD) 4.5, to examine whether increased cell death and changes in cardiac neural crest cells (NCC) play a role in Zn deficiency-induced heart defects. Fetuses were collected on GD 13.5, 15.5, and 18.5 and processed for GATA-4, FOG-2, connexin-43 (Cx43), HNK-1, smooth muscle alpha-actin (SMA) and cleaved caspase-3 protein expression. Fetuses from ZnA-fed dams showed normal heart development, whereas fetuses from dams fed with the ZnD diet exhibited a variety of heart anomalies, particularly in the region of the outflow tract. HNK-1 expression was lower than normal in the hearts of GD13.5 and 15.5 ZnD fetuses, particularly in the right atrium and in the distal tip of the interventricular septum. Conversely, Cx43 immunoreactivity was increased throughout the heart in fetuses from ZnD dams compared to fetuses from control dams. The distribution and intensity of expression of SMA, GATA-4, FOG-2, and markers of apoptosis were similar among the three groups. We propose that Zn deficiency induced alterations in the distribution of Cx43 and HNK-1 in fetal hearts contribute to the occurrence of the developmental heart anomalies.
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Affiliation(s)
- Veronica Lopez
- Department of Nutrition, University of California, Davis, One Shields Ave., Meyer Hall, Davis, CA 95616, USA
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237
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Brito FC, Kos L. Timeline and distribution of melanocyte precursors in the mouse heart. Pigment Cell Melanoma Res 2008; 21:464-70. [PMID: 18444965 DOI: 10.1111/j.1755-148x.2008.00459.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Apart from the well-studied melanocytes of the skin, eye and inner ear, another population has recently been described in the heart. In this study, we tracked cardiac melanoblasts using in situ hybridization with a dopachrome tautomerase (Dct) probe and Dct-LacZ transgenic mice. Large numbers of melanoblasts were found in the atrioventricular (AV) endocardial cushions at embryonic day (E) 14.5 and persisted in the AV valves into adulthood. The earliest time Dct-LacZ-positive cells were observed in the AV endocardial cushions was E12.5. Prior to that, between E10.5 and E11.5, small numbers of melanoblasts traveled between the post-otic area and third somite along the anterior and common cardinal veins and branchial arch arteries with other neural crest cells expressing CRABPI. Cardiac melanocytes were not found in the spotting mutants Ednrb s-l/s-l and Kit w-v/w-v, while large numbers were observed in transgenic mice that overexpress endothelin 3. These results indicate that cardiac melanocytes depend on the same signaling molecules known to be required for proper skin melanocyte development and may originate from the same precursor population. Cardiac melanocytes were not found in zebrafish or frog but were present in quail suggesting an association between cardiac melanocytes and four-chambered hearts.
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Affiliation(s)
- Flavia Carneiro Brito
- Department of Biological Sciences, Florida International University, Miami, Florida 33199, USA
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238
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Wu J, Williams JP, Rizvi TA, Kordich JJ, Witte D, Meijer D, Stemmer-Rachamimov AO, Cancelas JA, Ratner N. Plexiform and dermal neurofibromas and pigmentation are caused by Nf1 loss in desert hedgehog-expressing cells. Cancer Cell 2008; 13:105-16. [PMID: 18242511 PMCID: PMC2846699 DOI: 10.1016/j.ccr.2007.12.027] [Citation(s) in RCA: 162] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2007] [Revised: 10/12/2007] [Accepted: 12/26/2007] [Indexed: 12/14/2022]
Abstract
Neurofibromatosis type 1 (Nf1) mutation predisposes to benign peripheral nerve (glial) tumors called neurofibromas. The point(s) in development when Nf1 loss promotes neurofibroma formation are unknown. We show that inactivation of Nf1 in the glial lineage in vitro at embryonic day 12.5 + 1, but not earlier (neural crest) or later (mature Schwann cell), results in colony-forming cells capable of multilineage differentiation. In vivo, inactivation of Nf1 using a DhhCre driver beginning at E12.5 elicits plexiform neurofibromas, dermal neurofibromas, and pigmentation. Tumor Schwann cells uniquely show biallelic Nf1 inactivation. Peripheral nerve and tumors contain transiently proliferating Schwann cells that lose axonal contact, providing insight into early neurofibroma formation. We suggest that timing of Nf1 mutation is critical for neurofibroma formation.
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Affiliation(s)
- Jianqiang Wu
- Division of Experimental Hematology and Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45229
| | - Jon P. Williams
- Division of Experimental Hematology and Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45229
| | - Tilat A. Rizvi
- Division of Experimental Hematology and Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45229
| | - Jennifer J. Kordich
- Division of Experimental Hematology and Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45229
| | - David Witte
- Division of Pathology, Department of Pediatrics, Cincinnati Children’s Hospital, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45229
| | - Dies Meijer
- Departments of Cell Biology and Genetics, Erasmus University Medical Center, 3000DR Rotterdam, Netherlands
| | - Anat O. Stemmer-Rachamimov
- Departments of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
| | - Jose A. Cancelas
- Division of Experimental Hematology and Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45229
- Hoxworth Blood Center, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45229
| | - Nancy Ratner
- Division of Experimental Hematology and Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, Ohio, 45229
- Author for correspondence: Nancy Ratner: Tel: 513-636-9469
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239
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Breunig JJ, Silbereis J, Vaccarino FM, Šestan N, Rakic P. Notch regulates cell fate and dendrite morphology of newborn neurons in the postnatal dentate gyrus. Proc Natl Acad Sci U S A 2007; 104:20558-63. [PMID: 18077357 PMCID: PMC2154470 DOI: 10.1073/pnas.0710156104] [Citation(s) in RCA: 316] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2007] [Indexed: 12/20/2022] Open
Abstract
The lifelong addition of neurons to the hippocampus is a remarkable form of structural plasticity, yet the molecular controls over proliferation, neuronal fate determination, survival, and maturation are poorly understood. Expression of Notch1 was found to change dynamically depending on the differentiation state of neural precursor cells. Through the use of inducible gain- and loss-of-function of Notch1 mice we show that this membrane receptor is essential to these distinct processes. We found in vivo that activated Notch1 overexpression induces proliferation, whereas gamma-secretase inhibition or genetic ablation of Notch1 promotes cell cycle exit, indicating that the level of activated Notch1 regulates the magnitude of neurogenesis from postnatal progenitor cells. Abrogation of Notch signaling in vivo or in vitro leads to a transition from neural stem or precursor cells to transit-amplifying cells or neurons. Further, genetic Notch1 manipulation modulates survival and dendritic morphology of newborn granule cells. These results provide evidence for the expansive prevalence of Notch signaling in hippocampal morphogenesis and plasticity, suggesting that Notch1 could be a target of diverse traumatic and environmental modulators of adult neurogenesis.
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Affiliation(s)
| | - John Silbereis
- Child Study Center, Yale University School of Medicine, New Haven, CT 06520
| | - Flora M. Vaccarino
- *Department of Neurobiology
- Child Study Center, Yale University School of Medicine, New Haven, CT 06520
| | - Nenad Šestan
- *Department of Neurobiology
- Kavli Institute for Neuroscience, and
| | - Pasko Rakic
- *Department of Neurobiology
- Kavli Institute for Neuroscience, and
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240
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Hildreth V, Webb S, Bradshaw L, Brown NA, Anderson RH, Henderson DJ. Cells migrating from the neural crest contribute to the innervation of the venous pole of the heart. J Anat 2007; 212:1-11. [PMID: 18031480 DOI: 10.1111/j.1469-7580.2007.00833.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Cells migrating from the neural crest are known to septate the outflow tract of the developing heart, and to contribute to the formation of the arterial valves, their supporting sinuses, the coronary arteries and cardiac neural ganglia. Neural crest cells have also been suggested to contribute to development of the venous pole of the heart, but the extent and fate of such cells remains unclear. In this study, in the mouse, it is shown that cells from the neural crest contribute to the parasympathetic and, to a lesser extent, the sympathetic innervation of the venous pole of the heart. Nerves within the venous pole of the heart are shown to be of mixed origin, with some being derived from the neural crest, while others have an alternative origin, presumably placodal. The neurons innervating the nodal tissue, which can exert chronotropic effects on cardiac conduction, are shown not to be derived from the neural crest. In particular, no evidence was found to support previous suggestions that cells from the neural crest make a direct contribution to the myocardial atrioventricular conduction axis, although a small subset of these cells do co-localize with the developing left bundle branch. We have therefore confirmed that cells from the neural crest migrate to the venous pole of the heart, and that their major role is in the development of the parasympathetic innervation. In addition, in some embryos, a population of cells derived from the neural crest persist in the leaflets of the atrioventricular valves, but their role in subsequent development remains unknown.
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241
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Nakamura T, Colbert M, Krenz M, Molkentin JD, Hahn HS, Dorn GW, Robbins J. Mediating ERK 1/2 signaling rescues congenital heart defects in a mouse model of Noonan syndrome. J Clin Invest 2007; 117:2123-32. [PMID: 17641779 PMCID: PMC1913487 DOI: 10.1172/jci30756] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2006] [Accepted: 05/08/2007] [Indexed: 01/20/2023] Open
Abstract
Noonan syndrome (NS) is an autosomal dominant disorder characterized by a wide spectrum of defects, which most frequently include proportionate short stature, craniofacial anomalies, and congenital heart disease (CHD). NS is the most common nonchromosomal cause of CHD, and 80%-90% of NS patients have cardiac involvement. Mutations within the protein tyrosine phosphatase Src homology region 2, phosphatase 2 (SHP2) are responsible for approximately 50% of the cases of NS with cardiac involvement. To understand the developmental stage- and cell type-specific consequences of the NS SHP2 gain-of-function mutation, Q79R, we generated transgenic mice in which the mutated protein was expressed during gestation or following birth in cardiomyocytes. Q79R SHP2 embryonic hearts showed altered cardiomyocyte cell cycling, ventricular noncompaction, and ventricular septal defects, while, in the postnatal cardiomyocyte, Q79R SHP2 expression was completely benign. Fetal expression of Q79R led to the specific activation of the ERK1/2 pathway, and breeding of the Q79R transgenics into ERK1/2-null backgrounds confirmed the pathway's necessity and sufficiency in mediating mutant SHP2's effects. Our data establish the developmental stage-specific effects of Q79R cardiac expression in NS; show that ablation of subsequent ERK1/2 activation prevents the development of cardiac abnormalities; and suggest that ERK1/2 modulation could have important implications for developing therapeutic strategies in CHD.
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MESH Headings
- Amino Acid Substitution
- Animals
- Chromosome Disorders/embryology
- Chromosome Disorders/enzymology
- Chromosome Disorders/genetics
- Chromosome Disorders/pathology
- Chromosome Disorders/therapy
- Disease Models, Animal
- Gene Expression Regulation, Developmental/genetics
- Gene Expression Regulation, Enzymologic/genetics
- Heart Septal Defects, Ventricular/embryology
- Heart Septal Defects, Ventricular/enzymology
- Heart Septal Defects, Ventricular/genetics
- Heart Septal Defects, Ventricular/pathology
- Heart Septal Defects, Ventricular/prevention & control
- Heart Ventricles/embryology
- Heart Ventricles/enzymology
- Heart Ventricles/pathology
- Humans
- Intracellular Signaling Peptides and Proteins/genetics
- MAP Kinase Signaling System/genetics
- Mice
- Mice, Transgenic
- Mitogen-Activated Protein Kinase 1/genetics
- Mitogen-Activated Protein Kinase 1/metabolism
- Mitogen-Activated Protein Kinase 3/genetics
- Mitogen-Activated Protein Kinase 3/metabolism
- Mutation, Missense
- Myocytes, Cardiac/enzymology
- Myocytes, Cardiac/pathology
- Noonan Syndrome/embryology
- Noonan Syndrome/enzymology
- Noonan Syndrome/genetics
- Noonan Syndrome/pathology
- Noonan Syndrome/therapy
- Protein Phosphatase 2
- Protein Tyrosine Phosphatase, Non-Receptor Type 11
- Protein Tyrosine Phosphatases/biosynthesis
- Protein Tyrosine Phosphatases/genetics
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Affiliation(s)
- Tomoki Nakamura
- Cincinnati Children’s Hospital Medical Center, The Children’s Hospital Research Foundation, Division of Molecular Cardiovascular Biology, Cincinnati, Ohio, USA.
Department of Internal Medicine and Department of Cardiology, University of Cincinnati Medical Center, Cincinnati, Ohio, USA
| | - Melissa Colbert
- Cincinnati Children’s Hospital Medical Center, The Children’s Hospital Research Foundation, Division of Molecular Cardiovascular Biology, Cincinnati, Ohio, USA.
Department of Internal Medicine and Department of Cardiology, University of Cincinnati Medical Center, Cincinnati, Ohio, USA
| | - Maike Krenz
- Cincinnati Children’s Hospital Medical Center, The Children’s Hospital Research Foundation, Division of Molecular Cardiovascular Biology, Cincinnati, Ohio, USA.
Department of Internal Medicine and Department of Cardiology, University of Cincinnati Medical Center, Cincinnati, Ohio, USA
| | - Jeffery D. Molkentin
- Cincinnati Children’s Hospital Medical Center, The Children’s Hospital Research Foundation, Division of Molecular Cardiovascular Biology, Cincinnati, Ohio, USA.
Department of Internal Medicine and Department of Cardiology, University of Cincinnati Medical Center, Cincinnati, Ohio, USA
| | - Harvey S. Hahn
- Cincinnati Children’s Hospital Medical Center, The Children’s Hospital Research Foundation, Division of Molecular Cardiovascular Biology, Cincinnati, Ohio, USA.
Department of Internal Medicine and Department of Cardiology, University of Cincinnati Medical Center, Cincinnati, Ohio, USA
| | - Gerald W. Dorn
- Cincinnati Children’s Hospital Medical Center, The Children’s Hospital Research Foundation, Division of Molecular Cardiovascular Biology, Cincinnati, Ohio, USA.
Department of Internal Medicine and Department of Cardiology, University of Cincinnati Medical Center, Cincinnati, Ohio, USA
| | - Jeffrey Robbins
- Cincinnati Children’s Hospital Medical Center, The Children’s Hospital Research Foundation, Division of Molecular Cardiovascular Biology, Cincinnati, Ohio, USA.
Department of Internal Medicine and Department of Cardiology, University of Cincinnati Medical Center, Cincinnati, Ohio, USA
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242
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Wirrig EE, Snarr BS, Chintalapudi MR, O’Neal J, Phelps AL, Barth JL, Fresco VM, Kern CB, Mjaatvedt CH, Toole BP, Hoffman S, Trusk TC, Argraves WS, Wessels A. Cartilage link protein 1 (Crtl1), an extracellular matrix component playing an important role in heart development. Dev Biol 2007; 310:291-303. [PMID: 17822691 PMCID: PMC2254939 DOI: 10.1016/j.ydbio.2007.07.041] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2007] [Revised: 06/29/2007] [Accepted: 07/27/2007] [Indexed: 11/29/2022]
Abstract
To expand our insight into cardiac development, a comparative DNA microarray analysis was performed using tissues from the atrioventricular junction (AVJ) and ventricular chambers of mouse hearts at embryonic day (ED) 10.5-11.0. This comparison revealed differential expression of approximately 200 genes, including cartilage link protein 1 (Crtl1). Crtl1 stabilizes the interaction between hyaluronan (HA) and versican, two extracellular matrix components essential for cardiac development. Immunohistochemical studies showed that, initially, Crtl1, versican, and HA are co-expressed in the endocardial lining of the heart, and in the endocardially derived mesenchyme of the AVJ and outflow tract (OFT). At later stages, this co-expression becomes restricted to discrete populations of endocardially derived mesenchyme. Histological analysis of the Crtl1-deficient mouse revealed a spectrum of cardiac malformations, including AV septal and myocardial defects, while expression studies showed a significant reduction in versican levels. Subsequent analysis of the hdf mouse, which carries an insertional mutation in the versican gene (CSPG2), demonstrated that haploinsufficient versican mice display septal defects resembling those seen in Crtl1(-/-) embryos, suggesting that reduced versican expression may contribute to a subset of the cardiac abnormalities observed in the Crtl1(-/-) mouse. Combined, these findings establish an important role for Crtl1 in heart development.
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Affiliation(s)
- Elaine E Wirrig
- Department of Cell Biology and Anatomy. Cardiovascular Developmental, Biology Center. Medical University of South Carolina. Charleston SC, 29425 USA
| | - Brian S Snarr
- Department of Cell Biology and Anatomy. Cardiovascular Developmental, Biology Center. Medical University of South Carolina. Charleston SC, 29425 USA
| | - Mastan R Chintalapudi
- Department of Cell Biology and Anatomy. Cardiovascular Developmental, Biology Center. Medical University of South Carolina. Charleston SC, 29425 USA
| | - Jessica O’Neal
- Department of Cell Biology and Anatomy. Cardiovascular Developmental, Biology Center. Medical University of South Carolina. Charleston SC, 29425 USA
| | - Aimee L Phelps
- Department of Cell Biology and Anatomy. Cardiovascular Developmental, Biology Center. Medical University of South Carolina. Charleston SC, 29425 USA
| | - Jeremy L Barth
- Department of Cell Biology and Anatomy. Cardiovascular Developmental, Biology Center. Medical University of South Carolina. Charleston SC, 29425 USA
| | - Victor M Fresco
- Department of Cell Biology and Anatomy. Cardiovascular Developmental, Biology Center. Medical University of South Carolina. Charleston SC, 29425 USA
| | - Christine B Kern
- Department of Cell Biology and Anatomy. Cardiovascular Developmental, Biology Center. Medical University of South Carolina. Charleston SC, 29425 USA
| | - Corey H Mjaatvedt
- Department of Cell Biology and Anatomy. Cardiovascular Developmental, Biology Center. Medical University of South Carolina. Charleston SC, 29425 USA
| | - Bryan P Toole
- Department of Cell Biology and Anatomy. Cardiovascular Developmental, Biology Center. Medical University of South Carolina. Charleston SC, 29425 USA
| | - Stanley Hoffman
- Division of Rheumatology & Immunology, Medical University of South Carolina. Charleston SC, 29425 USA
| | - Thomas C Trusk
- Department of Cell Biology and Anatomy. Cardiovascular Developmental, Biology Center. Medical University of South Carolina. Charleston SC, 29425 USA
| | - W Scott Argraves
- Department of Cell Biology and Anatomy. Cardiovascular Developmental, Biology Center. Medical University of South Carolina. Charleston SC, 29425 USA
| | - Andy Wessels
- Department of Cell Biology and Anatomy. Cardiovascular Developmental, Biology Center. Medical University of South Carolina. Charleston SC, 29425 USA
- Department of Pediatrics, Division of Pediatric Cardiology, Medical University of South Carolina. Charleston SC, 29425 USA
- Corresponding author: Andy Wessels, PhD, Department of Cell Biology and Anatomy, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425; Tel: 843 792 8183, Fax: 843 792 0664,
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243
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Elizari MV, Levi R, Acunzo RS, Chiale PA, Civetta MM, Ferreiro M, Sicouri S. To the Editor—Response:. Heart Rhythm 2007. [DOI: 10.1016/j.hrthm.2007.05.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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244
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Sedmera D. Development of cardiac conduction system in mammals with a focus on the anatomical, functional and medical/genetical aspects. J Appl Biomed 2007. [DOI: 10.32725/jab.2007.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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245
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Zhao B, Etter L, Hinton RB, Benson DW. BMP and FGF regulatory pathways in semilunar valve precursor cells. Dev Dyn 2007; 236:971-80. [PMID: 17326134 DOI: 10.1002/dvdy.21097] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In the developing atrioventricular (AV) valve, limb bud, and somites, cartilage cell lineage differentiation is regulated by bone morphogenetic protein (BMP), while fibroblast growth factor (FGF) controls tendon cell fate. We observed aggrecan and sox9, characteristic of cartilage cell types, and scleraxis and tenascin, characteristic of tendon cell types, in developing avian semilunar valves. Addition of BMP4 to outflow tract (OFT) precursor cells of young (E4.5) but not older (E6) chick embryos activated Smad1/5/8 and induced sox9 and aggrecan expression, while FGF4 treatment increased phosphorylated MAPK (dpERK) signaling and promoted expression of scleraxis and tenascin. These results identify BMP and FGF pathways that promote expression of cartilage- or tendon-like characteristics in semilunar valve precursor cells. In contrast to AV valve precursor cells, which diversify into leaflets (cartilage-like) or chordae tendineae (tendon-like), semilunar valve cells exhibit both cartilage- and tendon-like characteristics in the developing and mature valve cusp.
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Affiliation(s)
- Bin Zhao
- Division of Cardiology, MLC 7042, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA
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246
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Allen ZJ, Waclaw RR, Colbert MC, Campbell K. Molecular identity of olfactory bulb interneurons: transcriptional codes of periglomerular neuron subtypes. J Mol Histol 2007; 38:517-25. [PMID: 17624499 DOI: 10.1007/s10735-007-9115-4] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2007] [Accepted: 06/18/2007] [Indexed: 11/30/2022]
Abstract
Interneurons in the glomerular layer (GL) of the olfactory bulb represent a diverse set of cells, which can be identified by distinct expression of different neurotransmitters as well as calcium binding proteins. Using genetic based fate mapping, we show here that at least three of these different interneurons subtypes (i.e. dopaminergic, calbindin- and calretinin-expressing) derive from cells that express the homeobox genes Dlx5/6. The transcription factors ER81, Meis2, Pax6 and Sp8 have all been implicated in olfactory bulb interneuron development and each of these can be observed in Dlx5/6-derived periglomerular cells. Conversely, the T-box factors Tbr1 and Tbx21, which mark olfactory bulb projection neurons, are not expressed in the Dlx5/6-derived periglomerular cells. While the interneuron subtypes that are marked by Pax6 and Sp8 have been described, little information exists as to the specific subtypes that express ER81 or Meis2. We show here that ER81 is expressed in dopaminergic cells and in a subset of calretinin-expressing cells in the GL. Meis2 is found in dopaminergic and calbindin-expressing cells as well as in a subpopulation of the calretinin-expressing interneurons of the glomerular layer. These findings suggest that distinct transcriptional codes may underlie the differentiation of specific olfactory bulb interneuron subtypes.
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Affiliation(s)
- Zegary J Allen
- Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, OH 45229, USA
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247
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Snider P, Olaopa M, Firulli AB, Conway SJ. Cardiovascular development and the colonizing cardiac neural crest lineage. ScientificWorldJournal 2007; 7:1090-113. [PMID: 17619792 PMCID: PMC2613651 DOI: 10.1100/tsw.2007.189] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Although it is well established that transgenic manipulation of mammalian neural crest-related gene expression and microsurgical removal of premigratory chicken and Xenopus embryonic cardiac neural crest progenitors results in a wide spectrum of both structural and functional congenital heart defects, the actual functional mechanism of the cardiac neural crest cells within the heart is poorly understood. Neural crest cell migration and appropriate colonization of the pharyngeal arches and outflow tract septum is thought to be highly dependent on genes that regulate cell-autonomous polarized movement (i.e., gap junctions, cadherins, and noncanonical Wnt1 pathway regulators). Once the migratory cardiac neural crest subpopulation finally reaches the heart, they have traditionally been thought to participate in septation of the common outflow tract into separate aortic and pulmonary arteries. However, several studies have suggested these colonizing neural crest cells may also play additional unexpected roles during cardiovascular development and may even contribute to a crest-derived stem cell population. Studies in both mice and chick suggest they can also enter the heart from the venous inflow as well as the usual arterial outflow region, and may contribute to the adult semilunar and atrioventricular valves as well as part of the cardiac conduction system. Furthermore, although they are not usually thought to give rise to the cardiomyocyte lineage, neural crest cells in the zebrafish (Danio rerio) can contribute to the myocardium and may have different functions in a species-dependent context. Intriguingly, both ablation of chick and Xenopus premigratory neural crest cells, and a transgenic deletion of mouse neural crest cell migration or disruption of the normal mammalian neural crest gene expression profiles, disrupts ventral myocardial function and/or cardiomyocyte proliferation. Combined, this suggests that either the cardiac neural crest secrete factor/s that regulate myocardial proliferation, can signal to the epicardium to subsequently secrete a growth factor/s, or may even contribute directly to the heart. Although there are species differences between mouse, chick, and Xenopus during cardiac neural crest cell morphogenesis, recent data suggest mouse and chick are more similar to each other than to the zebrafish neural crest cell lineage. Several groups have used the genetically defined Pax3 (splotch) mutant mice model to address the role of the cardiac neural crest lineage. Here we review the current literature, the neural crest-related role of the Pax3 transcription factor, and discuss potential function/s of cardiac neural crest-derived cells during cardiovascular developmental remodeling.
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Affiliation(s)
- Paige Snider
- Cardiovascular Development Group,
Herman B. Wells Center for Pediatric Research,
Indiana University School of Medicine,
Indianapolis, IN 46202,
USA
| | - Michael Olaopa
- Cardiovascular Development Group,
Herman B. Wells Center for Pediatric Research,
Indiana University School of Medicine,
Indianapolis, IN 46202,
USA
| | - Anthony B. Firulli
- Cardiovascular Development Group,
Herman B. Wells Center for Pediatric Research,
Indiana University School of Medicine,
Indianapolis, IN 46202,
USA
| | - Simon J. Conway
- Cardiovascular Development Group,
Herman B. Wells Center for Pediatric Research,
Indiana University School of Medicine,
Indianapolis, IN 46202,
USA
- *Simon J. Conway:
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248
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Snarr BS, Wirrig EE, Phelps AL, Trusk TC, Wessels A. A spatiotemporal evaluation of the contribution of the dorsal mesenchymal protrusion to cardiac development. Dev Dyn 2007; 236:1287-94. [PMID: 17265457 PMCID: PMC4003411 DOI: 10.1002/dvdy.21074] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The mesenchymal tissues involved in cardiac septation are derived from different sources. In addition to endocardial-derived mesenchyme, the heart also receives contributions from the neural crest, the proepicardium, and the dorsal mesenchymal protrusion (DMP). Whereas the contributions of the neural crest and proepicardium have been thoroughly studied, the DMP has received little attention. Here, we present the results of a comprehensive spatiotemporal study of the DMP in cardiac development. Using the Tie2-Cre mouse, immunohistochemistry, and AMIRA reconstructions, we show that the DMP, in combination with the mesenchymal cap on the primary atrial septum, fuse with the major atrioventricular cushions to close the primary atrial foramen and to form the atrioventricular mesenchymal complex. In this complex, the DMP constitutes a discrete prominent mesenchymal component, wedged in between the major cushions. This new model for atrioventricular septation may provide novel insights into understanding the etiology of congenital cardiac malformations.
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Affiliation(s)
- Brian S. Snarr
- Department of Cell Biology and Anatomy, Cardiovascular Developmental Biology Center, Medical University of South Carolina, Charleston, South Carolina
| | - Elaine E. Wirrig
- Department of Cell Biology and Anatomy, Cardiovascular Developmental Biology Center, Medical University of South Carolina, Charleston, South Carolina
| | - Aimee L. Phelps
- Department of Cell Biology and Anatomy, Cardiovascular Developmental Biology Center, Medical University of South Carolina, Charleston, South Carolina
| | - Thomas C. Trusk
- Department of Cell Biology and Anatomy, Cardiovascular Developmental Biology Center, Medical University of South Carolina, Charleston, South Carolina
| | - Andy Wessels
- Department of Cell Biology and Anatomy, Cardiovascular Developmental Biology Center, Medical University of South Carolina, Charleston, South Carolina
- Department of Pediatrics, Division of Pediatric Cardiology, Medical University of South Carolina, Charleston, South Carolina
- Correspondence to: Andy Wessels, Ph.D., Department of Cell Biology and Anatomy, Cardiovascular Developmental Biology Center, Medical University of South Carolina, 173 Ashley Avenue, Basic Science Building, Room 648B, P.O. Box 250508, Charleston, SC 29425.
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Sievers HH. In vivo tissue engineering an autologous semilunar biovalve: Can we get what we want? J Thorac Cardiovasc Surg 2007; 134:20-2, 22.e1. [PMID: 17599481 DOI: 10.1016/j.jtcvs.2007.03.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2007] [Revised: 03/21/2007] [Accepted: 03/29/2007] [Indexed: 10/23/2022]
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Abstract
The origins of vascular smooth muscle are far more diverse than previously thought. Lineage mapping studies show that the segmental organization of early vertebrate embryos leaves footprints on the adult vascular system in the form of a mosaic pattern of different smooth muscle types. Moreover, evolutionarily conserved tissue forming pathways produce vascular smooth muscle from a variety of unanticipated sources. A closer look at the diversity of smooth muscle origins in vascular development provides new perspectives about how blood vessels differ from one another and why they respond in disparate ways to common risk factors associated with vascular disease. The origins of vascular smooth muscle are far more diverse than previously thought. A closer look at the diversity of smooth muscle origins in vascular development provides new perspectives about how blood vessels differ from one another and why they respond in disparate ways to common risk factors associated with vascular disease.
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Affiliation(s)
- Mark W Majesky
- Department of Medicine, Carolina Cardiovascular Biology Center, University of North Carolina, Chapel Hill, NC 27599-7126, USA.
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