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Nie S. Use of Frogs as a Model to Study the Etiology of HLHS. J Cardiovasc Dev Dis 2023; 10:51. [PMID: 36826547 PMCID: PMC9965361 DOI: 10.3390/jcdd10020051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 01/25/2023] [Accepted: 01/27/2023] [Indexed: 01/31/2023] Open
Abstract
A frog is a classical model organism used to uncover processes and regulations of early vertebrate development, including heart development. Recently, we showed that a frog also represents a useful model to study a rare human congenital heart disease, hypoplastic left heart syndrome. In this review, we first summarized the cellular events and molecular regulations of vertebrate heart development, and the benefit of using a frog model to study congenital heart diseases. Next, we described the challenges in elucidating the etiology of hypoplastic left heart syndrome and discussed how a frog model may contribute to our understanding of the molecular and cellular bases of the disease. We concluded that a frog model offers its unique advantage in uncovering the cellular mechanisms of hypoplastic left heart syndrome; however, combining multiple model organisms, including frogs, is needed to gain a comprehensive understanding of the disease.
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Affiliation(s)
- Shuyi Nie
- School of Biological Sciences, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
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2
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de Sena-Tomás C, Aleman AG, Ford C, Varshney A, Yao D, Harrington JK, Saúde L, Ramialison M, Targoff KL. Activation of Nkx2.5 transcriptional program is required for adult myocardial repair. Nat Commun 2022; 13:2970. [PMID: 35624100 PMCID: PMC9142600 DOI: 10.1038/s41467-022-30468-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 05/03/2022] [Indexed: 11/09/2022] Open
Abstract
The cardiac developmental network has been associated with myocardial regenerative potential. However, the embryonic signals triggered following injury have yet to be fully elucidated. Nkx2.5 is a key causative transcription factor associated with human congenital heart disease and one of the earliest markers of cardiac progenitors, thus it serves as a promising candidate. Here, we show that cardiac-specific RNA-sequencing studies reveal a disrupted embryonic transcriptional profile in the adult Nkx2.5 loss-of-function myocardium. nkx2.5-/- fish exhibit an impaired ability to recover following ventricular apex amputation with diminished dedifferentiation and proliferation. Complex network analyses illuminate that Nkx2.5 is required to provoke proteolytic pathways necessary for sarcomere disassembly and to mount a proliferative response for cardiomyocyte renewal. Moreover, Nkx2.5 targets embedded in these distinct gene regulatory modules coordinate appropriate, multi-faceted injury responses. Altogether, our findings support a previously unrecognized, Nkx2.5-dependent regenerative circuit that invokes myocardial cell cycle re-entry, proteolysis, and mitochondrial metabolism to ensure effective regeneration in the teleost heart.
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Affiliation(s)
- Carmen de Sena-Tomás
- Division of Cardiology, Department of Pediatrics, College of Physicians & Surgeons, Columbia University, New York, NY, 10032, USA
| | - Angelika G Aleman
- Department of Physiology & Cellular Biophysics, College of Physicians & Surgeons, Columbia University, New York, NY, 10032, USA
| | - Caitlin Ford
- Department of Genetics & Development, College of Physicians & Surgeons, Columbia University, New York, NY, 10032, USA
| | - Akriti Varshney
- Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
- Australian Regenerative Medicine Institute & Systems Biology Institute Australia, Monash University, Clayton, VIC, 3800, Australia
| | - Di Yao
- Division of Cardiology, Department of Pediatrics, College of Physicians & Surgeons, Columbia University, New York, NY, 10032, USA
| | - Jamie K Harrington
- Division of Cardiology, Department of Pediatrics, College of Physicians & Surgeons, Columbia University, New York, NY, 10032, USA
| | - Leonor Saúde
- Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, 1649-028, Lisboa, Portugal
| | - Mirana Ramialison
- Australian Regenerative Medicine Institute & Systems Biology Institute Australia, Monash University, Clayton, VIC, 3800, Australia
- Murdoch Children's Research Institute & Department of Peadiatrics, The University of Melbourne, Parkville, VIC, 3052, Australia
| | - Kimara L Targoff
- Division of Cardiology, Department of Pediatrics, College of Physicians & Surgeons, Columbia University, New York, NY, 10032, USA.
- Columbia Stem Cell Initiative, Columbia University, New York, NY, 10032, USA.
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Dixit R, Narasimhan C, Balekundri VI, Agrawal D, Kumar A, Mohapatra B. Functional analysis of novel genetic variants of NKX2-5 associated with nonsyndromic congenital heart disease. Am J Med Genet A 2021; 185:3644-3663. [PMID: 34214246 DOI: 10.1002/ajmg.a.62413] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 06/04/2021] [Accepted: 06/11/2021] [Indexed: 01/26/2023]
Abstract
NKX2-5, a master cardiac regulatory transcription factor was the first known genetic cause of congenital heart diseases (CHDs). To further investigate its role in CHD pathogenesis, we performed mutational screening of 285 CHD probands and 200 healthy controls. Five coding sequence variants were identified in six CHD cases (2.1%), including three in the N-terminal region (p.A61G, p.R95L, and p.E131K) and one each in homeodomain (HD) (p.A148E) and tyrosine-rich domain (p.P247A). Variant-p.A148E showed tertiary structure changes and differential DNA binding affinity of mutant compared to wild type. Two N-terminal variants-p.A61G and p.E131K along with HD variant p.A148E demonstrated significantly reduced transcriptional activity of Nppa and Actc1 promoters in dual luciferase promoter assay supported by their reduced expression in qRT-PCR. Nonetheless, variant p.R95L affected the synergy of NKX2-5 with serum response factor and TBX5 leading to significantly decreased Actc1 promoter activity depicting a distinctive role of this region. The aberrant expression of other target genes-Irx4, Mef2c, Bmp10, Myh6, Myh7, and Myocd is also observed in response to NKX2-5 variants, possibly due to the defective gene regulatory network. Severely impaired downstream promoter activities and abnormal expression of target genes due to N-terminal variants supports the emerging role of this region during cardiac-developmental pathways.
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Affiliation(s)
- Ritu Dixit
- Cytogenetics Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Chitra Narasimhan
- Department of Pediatric Cardiology, Sri Jayadeva Institute of Cardiovascular Sciences and Research, Bengaluru, Karnataka, India
| | - Vijayalakshmi I Balekundri
- Super Speciality Hospital, Pradhan Mantri Swasthya Suraksha Yojana (PMSSY), Medical College and Research Institute, Bengaluru, Karnataka, India
| | - Damyanti Agrawal
- Department of Cardiothoracic and Vascular Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Ashok Kumar
- Department of Pediatrics, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India
| | - Bhagyalaxmi Mohapatra
- Cytogenetics Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, India
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Colombo S, de Sena-Tomás C, George V, Werdich AA, Kapur S, MacRae CA, Targoff KL. Nkx genes establish second heart field cardiomyocyte progenitors at the arterial pole and pattern the venous pole through Isl1 repression. Development 2018; 145:dev.161497. [PMID: 29361575 DOI: 10.1242/dev.161497] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 12/04/2017] [Indexed: 12/28/2022]
Abstract
NKX2-5 is the most commonly mutated gene associated with human congenital heart defects (CHDs), with a predilection for cardiac pole abnormalities. This homeodomain transcription factor is a central regulator of cardiac development and is expressed in both the first and second heart fields (FHF and SHF). We have previously revealed essential functions of nkx2.5 and nkx2.7, two Nkx2-5 homologs expressed in zebrafish cardiomyocytes, in maintaining ventricular identity. However, the differential roles of these genes in the specific subpopulations of the anterior (aSHF) and posterior (pSHF) SHFs have yet to be fully defined. Here, we show that Nkx genes regulate aSHF and pSHF progenitors through independent mechanisms. We demonstrate that Nkx genes restrict proliferation of aSHF progenitors in the outflow tract, delimit the number of pSHF progenitors at the venous pole and pattern the sinoatrial node acting through Isl1 repression. Moreover, optical mapping highlights the requirement for Nkx gene dose in establishing electrophysiological chamber identity and in integrating the physiological connectivity of FHF and SHF cardiomyocytes. Ultimately, our results may shed light on the discrete errors responsible for NKX2-5-dependent human CHDs of the cardiac outflow and inflow tracts.
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Affiliation(s)
- Sophie Colombo
- Division of Cardiology, Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Carmen de Sena-Tomás
- Division of Cardiology, Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Vanessa George
- Division of Cardiology, Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Andreas A Werdich
- Brigham and Women's Hospital/Harvard Medical School, Cardiovascular Division, 75 Francis Street, Thorn 11, Boston, MA 02115, USA
| | - Sunil Kapur
- Brigham and Women's Hospital/Harvard Medical School, Cardiovascular Division, 75 Francis Street, Thorn 11, Boston, MA 02115, USA
| | - Calum A MacRae
- Brigham and Women's Hospital/Harvard Medical School, Cardiovascular Division, 75 Francis Street, Thorn 11, Boston, MA 02115, USA
| | - Kimara L Targoff
- Division of Cardiology, Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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Jung JH, Ko J, Lee EH, Choi KM, Kim M, Yim UH, Lee JS, Shim WJ. RNA seq- and DEG-based comparison of developmental toxicity in fish embryos of two species exposed to Iranian heavy crude oil. Comp Biochem Physiol C Toxicol Pharmacol 2017; 196:1-10. [PMID: 28257923 DOI: 10.1016/j.cbpc.2017.02.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 02/21/2017] [Accepted: 02/23/2017] [Indexed: 02/05/2023]
Abstract
To determine and compare the toxic effects of Iranian heavy crude oil (IHCO) on the embryonic development of two fish species, we examined transcriptome profiles using RNA-seq. The assembled contigs were 66,070 unigenes in olive flounder embryos and 76,498 unigenes in spotted seabass embryos. In the differential gene expression (DEG) profiles, olive flounder embryos showed different up- and down-regulated patterns than spotted seabass embryos in response to fresh IHCO (FIHCO) and weathered IHCO (WIHCO). In this work, we categorized DEG profiles into six pathways: ribosome, oxidative phosphorylation, Parkinson's disease, Alzheimer's disease, Huntington's disease, and cardiac muscle contraction, validating the expression patterns of 13 DEGs using real-time quantitative RT-PCR. The expression of the CYP1A, CYP1B1, and CYP1C1 genes in spotted seabass embryos was higher than in olive flounder embryos, whereas genes related to cell processing, development, and the immune system showed the opposite trend. Orthologous gene cluster analysis showed that olive flounder embryos were sensitive (fold change of genes with cutoff P<0.05) to both FIHCO and WIHCO, but spotted seabass embryos exhibited higher sensitivity to WIHCO than FIHCO, indicating that species-specific differences are likely to be reflected in population levels after oil spills. Overall, our study provides new insight on the different embryonic susceptibilities of two marine fish species to FIHCO and WIHCO and a better understanding of the underlying molecular mechanisms via RNA-seq and DEGs.
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Affiliation(s)
- Jee-Hyun Jung
- Oil & POPs Research Group, Korea Institute of Ocean Science & Technology, Geoje 53201, Republic of Korea; Department of Marine Environmental Science, Korea University of Science and Technology, Daejeon 34113, Republic of Korea.
| | - Junsu Ko
- Theragen Etex Bio Institute Inc., Suwon 16229, Republic of Korea
| | - Eun-Hee Lee
- Oil & POPs Research Group, Korea Institute of Ocean Science & Technology, Geoje 53201, Republic of Korea
| | - Kwang-Min Choi
- Oil & POPs Research Group, Korea Institute of Ocean Science & Technology, Geoje 53201, Republic of Korea
| | - Moonkoo Kim
- Oil & POPs Research Group, Korea Institute of Ocean Science & Technology, Geoje 53201, Republic of Korea; Department of Marine Environmental Science, Korea University of Science and Technology, Daejeon 34113, Republic of Korea
| | - Un Hyuk Yim
- Oil & POPs Research Group, Korea Institute of Ocean Science & Technology, Geoje 53201, Republic of Korea; Department of Marine Environmental Science, Korea University of Science and Technology, Daejeon 34113, Republic of Korea
| | - Jae-Seong Lee
- Department of Biological Science, College of Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Won Joon Shim
- Oil & POPs Research Group, Korea Institute of Ocean Science & Technology, Geoje 53201, Republic of Korea; Department of Marine Environmental Science, Korea University of Science and Technology, Daejeon 34113, Republic of Korea
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Li FF, Deng X, Zhou J, Yan P, Zhao EY, Liu SL. Characterization of human bone morphogenetic protein gene variants for possible roles in congenital heart disease. Mol Med Rep 2016; 14:1459-64. [PMID: 27357418 PMCID: PMC4940093 DOI: 10.3892/mmr.2016.5428] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 04/25/2016] [Indexed: 12/25/2022] Open
Abstract
Congenital heart disease (CHD) is a complex illness with high rates of morbidity and mortality. In embryonic development, the heart is the first formed organ, which is strictly controlled by gene regulatory networks, including transcription factors, signaling pathways, epigenetic factors and microRNAs. Bone morphogenetic protein (BMP)-2 and -4 are essential in cardiogenesis as they can induce the expression of transcription factors, NKX2-5 and GATA binding protein 4, which are important in the development of the heart. The inhibition of BMP-2 and 4- inhibits the late expression of NKX2-5 and affects cardiac differentiation. The aim of the present study was to investigate whether BMP-2 and -4 variations may be associated with CHD in Chinese Han populations. The rs1049007, rs235768 and rs17563 single nucleotide polymorphisms (SNPs), which are genetic variations located within the translated region of the BMP-2 and -4, were evaluated in 230 patients with CHD from the Chinese Han population and 160 non CHD control individuals. Statistical analyses were performed using the χ2 test, implemented using SPSS software (version 13.0). The Hardy Weinberg equilibrium test was performed on the population using online Online Encyclopedia for Genetic Epidemiology studies software, and multiple-sequence alignments of the BMP proteins were performed using Vector NTI software. No statistically significant associations were identified between these genetic variations and the risk of CHD (rs1049007, P value=0.560; rs235768, P value=0.972; rs17563, P value=0.787). In addition, no correlation was found between the patients with CHD and the non-CHD control individuals. Therefore, the rs1049007, rs235768 and rs17563 genetic variations of BMP-2 were not associated with CHD in the Chinese Han population.
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Affiliation(s)
- Fei-Feng Li
- Genomics Research Center (one of the State‑Key Laboratory of Biopharmaceutical Engineering), Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China
| | - Xia Deng
- Genomics Research Center (one of the State‑Key Laboratory of Biopharmaceutical Engineering), Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China
| | - Jing Zhou
- Intensive Care Unit, The Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150086, P.R. China
| | - Peng Yan
- Department of Colorectal Surgery, The Second Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150086, P.R. China
| | - Er-Ying Zhao
- Genomics Research Center (one of the State‑Key Laboratory of Biopharmaceutical Engineering), Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China
| | - Shu-Lin Liu
- Genomics Research Center (one of the State‑Key Laboratory of Biopharmaceutical Engineering), Harbin Medical University, Harbin, Heilongjiang 150081, P.R. China
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7
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George V, Colombo S, Targoff KL. An early requirement for nkx2.5 ensures the first and second heart field ventricular identity and cardiac function into adulthood. Dev Biol 2014; 400:10-22. [PMID: 25536398 DOI: 10.1016/j.ydbio.2014.12.019] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 12/02/2014] [Accepted: 12/16/2014] [Indexed: 10/24/2022]
Abstract
Temporally controlled mechanisms that define the unique features of ventricular and atrial cardiomyocyte identities are essential for the construction of a coordinated, morphologically intact heart. We have previously demonstrated an important role for nkx genes in maintaining ventricular identity, however, the specific timing of nkx2.5 function in distinct cardiomyocyte populations has yet to be elucidated. Here, we show that heat-shock induction of a novel transgenic line, Tg(hsp70l:nkx2.5-EGFP), during the initial stages of cardiomyocyte differentiation leads to rescue of chamber shape and identity in nkx2.5(-/-) embryos as chambers emerge. Intriguingly, our findings link an early role of this essential cardiac transcription factor with a later function. Moreover, these data reveal that nkx2.5 is also required in the second heart field as the heart tube forms, reflecting the temporal delay in differentiation of this population. Thus, our results support a model in which nkx genes induce downstream targets that are necessary to maintain chamber-specific identity in both early- and late-differentiating cardiomyocytes at discrete stages in cardiac morphogenesis. Furthermore, we show that overexpression of nkx2.5 during the first and second heart field development not only rescues the mutant phenotype, but also is sufficient for proper function of the adult heart. Taken together, these results shed new light on the stage-dependent mechanisms that sculpt chamber-specific cardiomyocytes and, therefore, have the potential to improve in vitro generation of ventricular cells to treat myocardial infarction and congenital heart disease.
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Affiliation(s)
- Vanessa George
- Division of Pediatric Cardiology, Department of Pediatrics, College of Physicians & Surgeons, Columbia University, 630 West 168th Street, New York, NY 10032 USA
| | - Sophie Colombo
- Division of Pediatric Cardiology, Department of Pediatrics, College of Physicians & Surgeons, Columbia University, 630 West 168th Street, New York, NY 10032 USA
| | - Kimara L Targoff
- Division of Pediatric Cardiology, Department of Pediatrics, College of Physicians & Surgeons, Columbia University, 630 West 168th Street, New York, NY 10032 USA.
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A novel NKX2.5 loss-of-function mutation associated with congenital bicuspid aortic valve. Am J Cardiol 2014; 114:1891-5. [PMID: 25438918 DOI: 10.1016/j.amjcard.2014.09.028] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 09/17/2014] [Accepted: 09/17/2014] [Indexed: 01/08/2023]
Abstract
Bicuspid aortic valve (BAV) is the most common form of congenital cardiovascular defect in humans and is associated with substantial morbidity and mortality. Emerging evidence demonstrates that genetic risk factors play an important role in the pathogenesis of BAV. However, BAV is a genetically heterogenous disorder, and the genetic defects underpinning BAV in most patients remain to be identified. In the present study, the coding exons and flanking introns of the NKX2.5 gene, which encodes a homeodomain-containing transcription factor essential for the normal development of the aortic valve, were sequenced in 142 unrelated patients with BAV. The available relatives of the mutation carrier and 200 unrelated healthy subjects used as controls were also genotyped for NKX2.5. The functional characteristics of the mutation were delineated by using a dual-luciferase reporter assay system. As a result, a novel heterozygous NKX2.5 mutation, p.K192X, was identified in a family with BAV transmitted in an autosomal dominant pattern. The nonsense mutation was absent in 400 control chromosomes. Functional analyses revealed that the mutant NKX2.5 had no transcriptional activity compared with its wild-type counterpart. Furthermore, the mutation abolished the synergistic transcriptional activation between NKX2.5 and GATA5, another transcription factor crucial for the aortic valvular morphogenesis. In conclusion, this study is the first to link an NKX2.5 loss-of-function mutation to enhanced susceptibility to human BAV, providing novel insight into the molecular mechanism of BAV and suggesting potential implications for genetic counseling and clinical care of families presenting with BAV.
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Sakata H, Maéno M. Nkx2.5 is involved in myeloid cell differentiation at anterior ventral blood islands in the Xenopus embryo. Dev Growth Differ 2014; 56:544-54. [PMID: 25283688 DOI: 10.1111/dgd.12155] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 07/22/2014] [Accepted: 07/23/2014] [Indexed: 11/28/2022]
Abstract
We have shown previously that two populations of myeloid cells emerge in the anterior and posterior ventral blood islands (aVBI and pVBI) at the different stages in Xenopus laevis embryo. In order to elucidate the regulatory mechanism of myeloid cell differentiation in the aVBI, we examined the role of Nkx2.5, an essential transcription factor for heart differentiation, in regulation of the myeloid cell differentiation in this region. Knockdown of endogenous Nkx2.5 by introducing MO into the dorsal marginal zone (DMZ) suppressed the expression of MHCα as well as that of mpo and spib in the resultant embryos and in DMZ explants made from the injected embryos. Expression of c/ebpα was less affected in the embryos injected with Nkx2.5 MO. The effect of Nkx2.5 MO in myeloid cell differentiation was recovered by coinjection of nkx2.5 or c/ebpα mRNA, indicating that Nkx2.5 functions at the same or the upper level of C/EBPα for the specification of myeloid cells. An attempt to identify transcription factors for myeloid cell differentiation in ventral marginal zone (VMZ) explants demonstrated that coinjection of two transcription factors out of three factors, namely C/EBPα, Nkx2.5 and GATA4, was sufficient to induce a certain amount of mpo expression. We suggest that C/EBPα is an unequivocal factor for myeloid cell differentiation in the aVBI and that Nkx2.5 and GATA4 cooperate with C/EBPα for promotion of myeloid cell differentiation.
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Affiliation(s)
- Hiroyuki Sakata
- Graduate School of Science and Technology, Niigata University, 8050 Ikarashi-2, Nishi-ku, Niigata, 950-2181, Japan
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Ashraf H, Pradhan L, Chang EI, Terada R, Ryan NJ, Briggs LE, Chowdhury R, Zárate MA, Sugi Y, Nam HJ, Benson DW, Anderson RH, Kasahara H. A mouse model of human congenital heart disease: high incidence of diverse cardiac anomalies and ventricular noncompaction produced by heterozygous Nkx2-5 homeodomain missense mutation. ACTA ACUST UNITED AC 2014; 7:423-433. [PMID: 25028484 DOI: 10.1161/circgenetics.113.000281] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Heterozygous human mutations of NKX2-5 are highly penetrant and associated with varied congenital heart defects. The heterozygous knockout of murine Nkx2-5, in contrast, manifests less profound cardiac malformations, with low disease penetrance. We sought to study this apparent discrepancy between human and mouse genetics. Because missense mutations in the NKX2-5 homeodomain (DNA-binding domain) are the most frequently reported type of human mutation, we replicated this genetic defect in a murine knockin model. METHODS AND RESULTS We generated a murine model in a 129/Sv genetic background by knocking-in an Nkx2-5 homeodomain missense mutation previously identified in humans. The mutation was located at homeodomain position 52Arg→Gly (R52G). All the heterozygous neonatal Nkx2-5(+/R52G) mice demonstrated a prominent trabecular layer in the ventricular wall, so called noncompaction, along with diverse cardiac anomalies, including atrioventricular septal defects, Ebstein malformation of the tricuspid valve, and perimembranous and muscular ventricular septal defects. In addition, P10 Nkx2-5(+/R52G) mice demonstrated atrial sepal anomalies, with significant increase in the size of the interatrial communication and fossa ovalis, and decrease in the length of the flap valve compared with control Nkx2-5(+/+) or Nkx2-5(+/-) mice. CONCLUSIONS The results of our study demonstrate that heterozygous missense mutation in the murine Nkx2-5 homeodomain (R52G) is highly penetrant and result in pleiotropic cardiac effects. Thus, in contrast to heterozygous Nkx2-5 knockout mice, the effects of the heterozygous knockin mimic findings in humans with heterozygous missense mutation in NKX2-5 homeodomain.
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Affiliation(s)
- Hassan Ashraf
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL 32610
| | - Lagnajeet Pradhan
- Department of Bioengineering, University of Texas at Dallas, TX 75080
| | - Eileen I Chang
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL 32610
| | - Ryota Terada
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL 32610
| | - Nicole J Ryan
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL 32610
| | - Laura E Briggs
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL 32610
| | - Rajib Chowdhury
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL 32610
| | - Miguel A Zárate
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL 32610
| | - Yukiko Sugi
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, SC 29425
| | - Hyun-Joo Nam
- Department of Bioengineering, University of Texas at Dallas, TX 75080
| | - D Woodrow Benson
- Department of Pediatrics, Herma Heart Center, Medical College of Wisconsin, Milwaukee, WI 53226
| | | | - Hideko Kasahara
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL 32610
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11
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Targoff KL, Colombo S, George V, Schell T, Kim SH, Solnica-Krezel L, Yelon D. Nkx genes are essential for maintenance of ventricular identity. Development 2013; 140:4203-13. [PMID: 24026123 DOI: 10.1242/dev.095562] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Establishment of specific characteristics of each embryonic cardiac chamber is crucial for development of a fully functional adult heart. Despite the importance of defining and maintaining unique features in ventricular and atrial cardiomyocytes, the regulatory mechanisms guiding these processes are poorly understood. Here, we show that the homeodomain transcription factors Nkx2.5 and Nkx2.7 are necessary to sustain ventricular chamber attributes through repression of atrial chamber identity. Mutation of nkx2.5 in zebrafish yields embryos with diminutive ventricular and bulbous atrial chambers. These chamber deformities emerge gradually during development, with a severe collapse in the number of ventricular cardiomyocytes and an accumulation of excess atrial cardiomyocytes as the heart matures. Removal of nkx2.7 function from nkx2.5 mutants exacerbates the loss of ventricular cells and the gain of atrial cells. Moreover, in these Nkx-deficient embryos, expression of vmhc, a ventricular gene, fades, whereas expression of amhc, an atrial gene, expands. Cell-labeling experiments suggest that ventricular cardiomyocytes can transform into atrial cardiomyocytes in the absence of Nkx gene function. Through suggestion of transdifferentiation from ventricular to atrial fate, our data reveal a pivotal role for Nkx genes in maintaining ventricular identity and highlight remarkable plasticity in differentiated myocardium. Thus, our results are relevant to the etiologies of fetal and neonatal cardiac pathology and could direct future innovations in cardiac regenerative medicine.
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Affiliation(s)
- Kimara L Targoff
- Developmental Genetics Program and Department of Cell Biology, Kimmel Center for Biology and Medicine, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA
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Bechtold-Dalla Pozza S, Hiedl S, Roeb J, Lohse P, Malik RE, Park S, Durán-Prado M, Rhodes SJ. A recessive mutation resulting in a disabling amino acid substitution (T194R) in the LHX3 homeodomain causes combined pituitary hormone deficiency. Horm Res Paediatr 2012; 77:41-51. [PMID: 22286346 PMCID: PMC3355643 DOI: 10.1159/000335929] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Accepted: 12/06/2011] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND/AIMS Recessive mutations in the LHX3 homeodomain transcription factor gene are associated with developmental disorders affecting the pituitary and nervous system. We describe pediatric patients with combined pituitary hormone deficiency (CPHD) who harbor a novel mutation in LHX3. METHODS Two female siblings from related parents were examined. Both patients had neonatal complications. The index patient had CPHD featuring deficiencies of GH, LH, FSH, PRL, and TSH, with later onset of ACTH deficiency. She also had a hypoplastic anterior pituitary, respiratory distress, hearing impairment, and limited neck rotation. The LHX3 gene was sequenced and the biochemical properties of the predicted altered proteins were characterized. RESULTS A novel homozygous mutation predicted to change amino acid 194 from threonine to arginine (T194R) was detected in both patients. This amino acid is conserved in the DNA-binding homeodomain. Computer modeling predicted that the T194R change would alter the homeodomain structure. The T194R protein did not bind tested LHX3 DNA recognition sites and did not activate the α-glycoprotein and PRL target genes. CONCLUSION The T194R mutation affects a critical residue in the LHX3 protein. This study extends our understanding of the phenotypic features, molecular mechanism, and developmental course associated with mutations in the LHX3 gene.
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Affiliation(s)
| | - Stefan Hiedl
- Pediatric Endocrinology and Diabetology, Ludwig Maximilians University of Munich, Munich, Germany
| | - Julia Roeb
- Pediatric Endocrinology and Diabetology, Ludwig Maximilians University of Munich, Munich, Germany
| | - Peter Lohse
- Clinical Chemistry-Grosshadern, Ludwig Maximilians University of Munich, Munich, Germany
| | - Raleigh E. Malik
- Biochemistry and Molecular Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Ind., USA
| | - Soyoung Park
- Biochemistry and Molecular Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Ind., USA
| | - Mario Durán-Prado
- Medical Sciences, University of Castilla la Mancha, Ciudad Real, Spain
| | - Simon J. Rhodes
- Biochemistry and Molecular Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Ind., USA,Cellular and Integrative Physiology, Indiana University-Purdue University Indianapolis, Indianapolis, Ind., USA,Biology, Indiana University-Purdue University Indianapolis, Indianapolis, Ind., USA,*Simon J. Rhodes, PhD, Cellular and Integrative Physiology, Indiana University School of Medicine, Medical Science Room 362A, 635 N. Barnhill Drive, Indianapolis, IN 46202-5120 (USA), Tel. +1 317 278 1797, E-Mail
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13
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Martin LK, Bratoeva M, Mezentseva NV, Bernanke JM, Rémond MC, Ramsdell AF, Eisenberg CA, Eisenberg LM. Inhibition of heart formation by lithium is an indirect result of the disruption of tissue organization within the embryo. Dev Growth Differ 2012; 54:153-66. [PMID: 22150286 PMCID: PMC3288208 DOI: 10.1111/j.1440-169x.2011.01313.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Lithium is a commonly used drug for the treatment of bipolar disorder. At high doses, lithium becomes teratogenic, which is a property that has allowed this agent to serve as a useful tool for dissecting molecular pathways that regulate embryogenesis. This study was designed to examine the impact of lithium on heart formation in the developing frog for insights into the molecular regulation of cardiac specification. Embryos were exposed to lithium at the beginning of gastrulation, which produced severe malformations of the anterior end of the embryo. Although previous reports characterized this deformity as a posteriorized phenotype, histological analysis revealed that the defects were more comprehensive, with disfigurement and disorganization of all interior tissues along the anterior-posterior axis. Emerging tissues were poorly segregated and cavity formation was decreased within the embryo. Lithium exposure also completely ablated formation of the heart and prevented myocardial cell differentiation. Despite the complete absence of cardiac tissue in lithium treated embryos, exposure to lithium did not prevent myocardial differentiation of precardiac dorsal marginal zone explants. Moreover, precardiac tissue freed from the embryo subsequent to lithium treatment at gastrulation gave rise to cardiac tissue, as demonstrated by upregulation of cardiac gene expression, display of sarcomeric proteins, and formation of a contractile phenotype. Together these data indicate that lithium's effect on the developing heart was not due to direct regulation of cardiac differentiation, but an indirect consequence of disrupted tissue organization within the embryo.
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Affiliation(s)
- Lisa K. Martin
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
| | - Momka Bratoeva
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
| | - Nadejda V. Mezentseva
- New York Medical College/Westchester Medical Center Stem Cell Laboratory, Departments of Physiology and Medicine, New York Medical College. Valhalla, NY 10595, USA
| | - Jayne M. Bernanke
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
| | - Mathieu C. Rémond
- New York Medical College/Westchester Medical Center Stem Cell Laboratory, Departments of Physiology and Medicine, New York Medical College. Valhalla, NY 10595, USA
| | - Ann F. Ramsdell
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina 29425, USA
| | - Carol A. Eisenberg
- New York Medical College/Westchester Medical Center Stem Cell Laboratory, Departments of Physiology and Medicine, New York Medical College. Valhalla, NY 10595, USA
| | - Leonard M. Eisenberg
- New York Medical College/Westchester Medical Center Stem Cell Laboratory, Departments of Physiology and Medicine, New York Medical College. Valhalla, NY 10595, USA
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14
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Taubenschmid J, Weitzer G. Mechanisms of cardiogenesis in cardiovascular progenitor cells. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2012; 293:195-267. [PMID: 22251563 PMCID: PMC7615846 DOI: 10.1016/b978-0-12-394304-0.00012-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Self-renewing cells of the vertebrate heart have become a major subject of interest in the past decade. However, many researchers had a hard time to argue against the orthodox textbook view that defines the heart as a postmitotic organ. Once the scientific community agreed on the existence of self-renewing cells in the vertebrate heart, their origin was again put on trial when transdifferentiation, dedifferentiation, and reprogramming could no longer be excluded as potential sources of self-renewal in the adult organ. Additionally, the presence of self-renewing pluripotent cells in the peripheral blood challenges the concept of tissue-specific stem and progenitor cells. Leaving these unsolved problems aside, it seems very desirable to learn about the basic biology of this unique cell type. Thus, we shall here paint a picture of cardiovascular progenitor cells including the current knowledge about their origin, basic nature, and the molecular mechanisms guiding proliferation and differentiation into somatic cells of the heart.
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Affiliation(s)
- Jasmin Taubenschmid
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria
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15
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Kaltenbrun E, Tandon P, Amin NM, Waldron L, Showell C, Conlon FL. Xenopus: An emerging model for studying congenital heart disease. ACTA ACUST UNITED AC 2011; 91:495-510. [PMID: 21538812 DOI: 10.1002/bdra.20793] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Revised: 01/18/2011] [Accepted: 01/28/2011] [Indexed: 02/02/2023]
Abstract
Congenital heart defects affect nearly 1% of all newborns and are a significant cause of infant death. Clinical studies have identified a number of congenital heart syndromes associated with mutations in genes that are involved in the complex process of cardiogenesis. The African clawed frog, Xenopus, has been instrumental in studies of vertebrate heart development and provides a valuable tool to investigate the molecular mechanisms underlying human congenital heart diseases. In this review, we discuss the methodologies that make Xenopus an ideal model system to investigate heart development and disease. We also outline congenital heart conditions linked to cardiac genes that have been well studied in Xenopus and describe some emerging technologies that will further aid in the study of these complex syndromes.
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Affiliation(s)
- Erin Kaltenbrun
- University of North Carolina McAllister Heart Institute, Chapel Hill, NC 27599, USA
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16
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Terada R, Warren S, Lu JT, Chien KR, Wessels A, Kasahara H. Ablation of Nkx2-5 at mid-embryonic stage results in premature lethality and cardiac malformation. Cardiovasc Res 2011; 91:289-99. [PMID: 21285290 DOI: 10.1093/cvr/cvr037] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
AIMS Human congenital heart disease linked to mutations in the homeobox transcription factor, NKX2-5, is characterized by cardiac anomalies, including atrial and ventricular septal defects as well as conduction and occasional defects in contractility. In the mouse, homozygous germline deletion of Nkx2-5 gene results in death around E10.5. It is, however, not established whether Nkx2-5 is necessary for cardiac development beyond this embryonic stage. Because human NKX2-5 mutations are related to septum secundum type atrial septal defects (ASD), we hypothesized that Nkx2-5 deficiency during the processes of septum secundum formation may cause cardiac anomalies; thus, we analysed mice with tamoxifen-inducible Nkx2-5 ablation beginning at E12.5 when the septum secundum starts to develop. METHODS AND RESULTS Using tamoxifen-inducible Nkx2-5 gene-targeted mice, this study demonstrates that Nkx2-5 ablation beginning at E12.5 results in embryonic death by E17.5. Analysis of mutant embryos at E16.5 shows arrhythmias, contraction defects, and cardiac malformations, including ASD. Quantitative measurements using serial section histology and three-dimensional reconstruction demonstrate growth retardation of the septum secundum and enlarged foramen ovale in Nkx2-5-ablated embryos. Functional cardiac defects may be attributed to abnormal expression of transcripts critical for conduction and contraction, including cardiac voltage-gated Na(+) channel pore-forming α-subunit (Na(v)1.5-α), gap junction protein connexin40, cardiac myosin light chain kinase, and sarcolipin within 4 days after tamoxifen injection. CONCLUSION Nkx2-5 is necessary for survival after the mid-embryonic stage for cardiac function and formation by regulating the expression of its downstream target genes.
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Affiliation(s)
- Ryota Terada
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, FL 32610-0274, USA
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17
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Martin J, Afouda BA, Hoppler S. Wnt/beta-catenin signalling regulates cardiomyogenesis via GATA transcription factors. J Anat 2010; 216:92-107. [PMID: 20402826 DOI: 10.1111/j.1469-7580.2009.01171.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
A functioning heart muscle is required continuously throughout life. During embryonic development the heart muscle tissue differentiates from mesoderm that has heart-forming potential. Heart-forming potential in the embryonic mesoderm is regulated by pro-cardiogenic transcription factors, such as members of the GATA and NK-2 transcription factor families. Subsequent heart muscle differentiation involves the expression of cytoskeletal proteins, including myosins and troponins. Different Wnt signalling pathways have various functions in heart development. So-called 'canonical' (Wnt/beta-catenin-mediated) signalling has a conserved role in vertebrate heart development, regulating and restricting heart development and subsequent heart muscle differentiation. Here we investigated the way in which Wnt/beta-catenin signalling functionally interacts with the GATA family of pro-cardiogenic transcription factors to regulate subsequent heart muscle differentiation. We used whole Xenopus embryos as an accessible experimental model system for vertebrate heart development. Our experiments confirmed that activation of Wnt signalling results in reduced gata gene expression, as well as reduced gene expression of other pro-cardiogenic transcription factors and heart muscle differentiation markers. Remarkably, we discovered that when GATA function is experimentally restored, the expression of other pro-cardiogenic transcription factors and heart muscle differentiation markers is rescued. These findings, obtained from whole-embryo experiments, show that Wnt signalling regulates heart development at the level of GATA factors, confirming earlier results from tissue-culture experiments. Furthermore, our rescue experiments in Xenopus embryos revealed differences in functional activity between the various GATA transcription factors involved in heart development. We discovered that GATA4 is more efficient at reinstating the gene expression of other pro-cardiogenic transcription factors, whereas GATA6 is more potent at promoting the expression of genes associated with terminal heart muscle differentiation. In conclusion, our findings show that the inhibition of heart development by Wnt/beta-catenin signalling during organogenesis is mediated by the loss of expression of GATA pro-cardiogenic transcription factors and reveal functional differences between those GATA factors in heart development.
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Affiliation(s)
- Jennifer Martin
- Cell and Developmental Biology Research Programme, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK
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18
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Bartlett H, Veenstra GJC, Weeks DL. Examining the cardiac NK-2 genes in early heart development. Pediatr Cardiol 2010; 31:335-41. [PMID: 19967350 PMCID: PMC2981039 DOI: 10.1007/s00246-009-9605-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Accepted: 11/11/2009] [Indexed: 12/14/2022]
Abstract
The cardiac NK-2 transcription factors are the vertebrate relatives of the Drosophila tinman gene. Without the Drosophila tinman gene, fruit flies fail to form their heart ("dorsal vessel"), and mutations or altered expression of cardiac NK-2 genes may lead to abnormal heart formation in vertebrates. Although the cardiac NK-2 gene NKX2-5 is recognized as an important factor in cases of human congenital heart disease and heart development in vertebrates, the roles of the other cardiac NK-2 genes are less clear. This report reviews what is known about the cardiac NK-2 genes in cardiac development, comparing studies in several different model systems.
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Affiliation(s)
- Heather Bartlett
- Department of Pediatrics, University of Iowa, Bowen Science Building, 51 Newton Road, Iowa City, IA 52242, USA
| | - Gert Jan C. Veenstra
- Department of Molecular Biology, Faculty of Science, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Daniel L. Weeks
- Department of Biochemistry, University of Iowa, Bowen Science Building, 51 Newton Road, Iowa City, IA 52242, USA,
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19
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Abu-Daya A, Sater AK, Wells DE, Mohun TJ, Zimmerman LB. Absence of heartbeat in the Xenopus tropicalis mutation muzak is caused by a nonsense mutation in cardiac myosin myh6. Dev Biol 2009; 336:20-9. [PMID: 19769958 PMCID: PMC2786259 DOI: 10.1016/j.ydbio.2009.09.019] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 08/17/2009] [Accepted: 09/14/2009] [Indexed: 11/25/2022]
Abstract
Mechanisms coupling heart function and cardiac morphogenesis can be
accessed in lower vertebrate embryos that can survive to swimming tadpole stages
on diffused oxygen. Forward genetic screens in Xenopus
tropicalis have identified more than 80 mutations affecting diverse
developmental processes, including cardiac morphogenesis and function. In the
first positional cloning of a mutation in X. tropicalis, we
show that non-contractile hearts in muzak (muz) embryos are
caused by a premature stop codon in the cardiac myosin heavy chain gene
myh6. The mutation deletes the coiled-coil domain
responsible for polymerization into thick filaments, severely disrupting the
cardiomyocyte cytoskeleton. Despite the lack of contractile activity and absence
of a major structural protein, early stages of cardiac morphogenesis including
looping and chamber formation are grossly normal. Muz hearts
subsequently develop dilated chambers with compressed endocardium and fail to
form identifiable cardiac valves and trabeculae.
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Affiliation(s)
- Anita Abu-Daya
- MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London, NW7 1AA, UK
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20
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Targoff KL, Schell T, Yelon D. Nkx genes regulate heart tube extension and exert differential effects on ventricular and atrial cell number. Dev Biol 2008; 322:314-21. [PMID: 18718462 DOI: 10.1016/j.ydbio.2008.07.037] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2008] [Revised: 06/24/2008] [Accepted: 07/30/2008] [Indexed: 10/21/2022]
Abstract
Heart formation is a complex morphogenetic process, and perturbations in cardiac morphogenesis lead to congenital heart disease. NKX2-5 is a key causative gene associated with cardiac birth defects, presumably because of its essential roles during the early steps of cardiogenesis. Previous studies in model organisms implicate NKX2-5 homologs in numerous processes, including cardiac progenitor specification, progenitor proliferation, and chamber morphogenesis. By inhibiting function of the zebrafish NKX2-5 homologs, nkx2.5 and nkx2.7, we show that nkx genes are essential to establish the original dimensions of the linear heart tube. The nkx-deficient heart tube fails to elongate normally: its ventricular portion is atypically short and wide, and its atrial portion is disorganized and sprawling. This atrial phenotype is associated with a surplus of atrial cardiomyocytes, whereas ventricular cell number is normal at this stage. However, ventricular cell number is decreased in nkx-deficient embryos later in development, when cardiac chambers are emerging. Thus, we conclude that nkx genes regulate heart tube extension and exert differential effects on ventricular and atrial cell number. Our data suggest that morphogenetic errors could originate during early stages of heart tube assembly in patients with NKX2-5 mutations.
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Affiliation(s)
- Kimara L Targoff
- Developmental Genetics Program and Department of Cell Biology, Kimmel Center for Biology and Medicine, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA
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21
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Nagao K, Taniyama Y, Kietzmann T, Doi T, Komuro I, Morishita R. HIF-1alpha signaling upstream of NKX2.5 is required for cardiac development in Xenopus. J Biol Chem 2008; 283:11841-9. [PMID: 18303027 DOI: 10.1074/jbc.m702563200] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
HIF-1alpha is originally identified as a transcription factor that activates gene expression in response to hypoxia. In metazoans, HIF-1alpha functions as a master regulator of oxygen homeostasis and regulates adaptive responses to change in oxygen tension during embryogenesis, tissue ischemia, and tumorigenesis. Because Hif-1alpha-deficient mice exhibit a number of developmental defects, the precise role of HIF-1alpha in early cardiac morphogenesis has been uncertain. Therefore, to clarify the role of HIF-1alpha in heart development, we investigated the effect of knockdown of HIF-1alpha in Xenopus embryos using antisense morpholino oligonucleotide microinjection techniques. Knockdown of HIF-1alpha resulted in defects of cardiogenesis. Whole mount in situ hybridization for cardiac troponin I (cTnI) showed the two separated populations of cardiomyocytes, which is indicative of cardia bifida, in HIF-1alpha-depleted embryos. Furthermore, the depletion of HIF-1alpha led to the reduction in cTnI expression, suggesting the correlation between HIF-1alpha and cardiac differentiation. We further examined the expression of several heart markers, nkx2.5, gata4, tbx5, bmp4, hand1, and hand2 in HIF-1alpha-depleted embryos. Among them, the expression of nkx2.5 was significantly reduced. Luciferase reporter assay using the Nkx2.5 promoter showed that knockdown of HIF-1alpha decreased its promoter activity. The cardiac abnormality in the HIF-1alpha-depleted embryo was restored with co-injection of nkx2.5 mRNA. Collectively, these findings reveal that HIF-1alpha-regulated nkx2.5 expression is required for heart development in Xenopus.
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Affiliation(s)
- Kaori Nagao
- Department of Clinical Gene Therapy, Graduate School of Medicine, Osaka University, Suita 565-0871, Japan
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22
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Akçaboy MI, Cengiz FB, Inceoğlu B, Uçar T, Atalay S, Tutar E, Tekin M. The effect of p.Arg25Cys alteration in NKX2-5 on conotruncal heart anomalies: mutation or polymorphism? Pediatr Cardiol 2008; 29:126-9. [PMID: 17891434 DOI: 10.1007/s00246-007-9058-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2006] [Revised: 12/01/2006] [Accepted: 07/02/2007] [Indexed: 11/30/2022]
Abstract
Heterozygous mutations in the NKX2-5 gene of patients with various congenital heart defects have been reported. Most of the congenital heart defects associated with the mutations in the NKX2-5 gene are conotruncal heart anomalies, primarily the tetralogy of Fallot. In this study, the authors screened 72 Turkish children with conotruncal heart anomalies and 185 healthy control subjects to find the NKX2-5 alterations. They found one previously documented NKX2-5 missense alteration, heterozygous c.73C>T (p.Arg25Cys), in a 10-year-old boy with tetralogy of Fallot. The same heterozygous alteration was found also in the patient's healthy father and in two unrelated persons in the healthy control group. The current study shows for the first time the presence of p.Arg25Cys in healthy control subjects other than African Americans. These results show that no genetic support exists for the pathogenecity of this alteration, although a previous in vitro study and theoretical predictions suggest a structural/functional difference in the altered protein region.
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Affiliation(s)
- M I Akçaboy
- Division of Pediatric Genetics, Ankara University School of Medicine, Birlik Mah. 65. Sok. No: 20/7, Cankaya, Ankara 06610, Turkey
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Bartlett HL, Sutherland L, Kolker SJ, Welp C, Tajchman U, Desmarais V, Weeks DL. Transient early embryonic expression of Nkx2-5 mutations linked to congenital heart defects in human causes heart defects in Xenopus laevis. Dev Dyn 2007; 236:2475-84. [PMID: 17685485 PMCID: PMC2078326 DOI: 10.1002/dvdy.21244] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Nkx2-5 is a homeobox containing transcription factor that is conserved and expressed in organisms that form hearts. Fruit flies lacking the gene (tinman) fail to form a dorsal vessel, mice that are homozygous null for Nkx2-5 form small, deformed hearts, and several human cardiac defects have been linked to dominant mutations in the Nkx2-5 gene. The Xenopus homologs (XNkx2-5) of two truncated forms of Nkx2-5 that have been identified in humans with congenital heart defects were used in the studies reported here. mRNAs encoding these mutations were injected into single cell Xenopus embryos, and heart development was monitored. Our results indicate that the introduction of truncated XNkx2-5 variants leads to three principle developmental defects. The atrial septum and the valve of the atrioventricular canal were both abnormal. In addition, video microscopic timing of heart contraction indicated that embryos injected with either mutant form of XNkx2-5 have conduction defects.
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Affiliation(s)
| | - Lillian Sutherland
- Department of Biochemistry, Bowen Science Building, University of Iowa, Iowa City, Iowa
| | - Sandra J. Kolker
- Department of Biochemistry, Bowen Science Building, University of Iowa, Iowa City, Iowa
| | - Chelsea Welp
- Department of Pediatrics, University of Iowa, Iowa City, Iowa
| | | | - Vera Desmarais
- Department of Biochemistry, Bowen Science Building, University of Iowa, Iowa City, Iowa
| | - Daniel L. Weeks
- Department of Biochemistry, Bowen Science Building, University of Iowa, Iowa City, Iowa
- *Correspondence to: Daniel L. Weeks, Department of Biochemistry, Bowen Science Building, University of Iowa, Iowa City, IA 52242-1109. E-mail:
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Srivastava D. Genetic regulation of cardiogenesis and congenital heart disease. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2007; 1:199-213. [PMID: 18039113 DOI: 10.1146/annurev.pathol.1.110304.100039] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Developmental heart disorders are the most common of all human birth defects and occur in nearly one percent of the population. Survivors of congenital heart malformations are an increasing population, and it is becoming clear that genetic mutations that cause developmental anomalies may result in cardiac dysfunction later in life. This review highlights the progress in understanding the underlying molecular basis for cardiac formation and how disruption of the intricate steps of cardiogenesis can lead to congenital heart defects. The lessons learned from examining the early steps of heart formation are essential for informing the prevention of malformations and their long-term consequences, as well as for approaches to guide stem cells into cardiac lineages.
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Affiliation(s)
- Deepak Srivastava
- Gladstone Institute of Cardiovascular Disease, Department of Pediatrics, University of California, San Francisco, California 94158, USA.
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25
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Hendren JD, Shah AP, Arguelles AM, Cripps RM. Cardiac expression of the Drosophila Sulphonylurea receptor gene is regulated by an intron enhancer dependent upon the NK homeodomain factor Tinman. Mech Dev 2007; 124:416-26. [PMID: 17433632 PMCID: PMC1955464 DOI: 10.1016/j.mod.2007.03.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2006] [Revised: 02/07/2007] [Accepted: 03/01/2007] [Indexed: 11/16/2022]
Abstract
Cardiac development proceeds via the activation of a complex network of regulatory factors which both directly and indirectly impact downstream cardiac structural genes. In Drosophila, the NK homeodomain transcription factor Tinman is critical to cardiac specification and development via the activation of a number of key regulatory genes which mediate heart development. In this manuscript, we demonstrate that Tinman also functions in Drosophila to directly activate transcription of the ATP binding cassette gene Sulphonylurea receptor (Sur). Cardiac expression of Sur is regulated by Tinman via an intron enhancer which first becomes active at stage 12 of embryogenesis, and whose function is restricted to the Tin cardial cells by the end of embryogenesis. Cardiac Sur enhancer activity subsequently persists through larval and adult development, but interestingly becomes modulated in several unique subsets of Tin-expressing cardial cells. The cardiac enhancer contains four binding sites for Tinman protein; mutation of two of these sites significantly reduces enhancer activity at all stages of development, and activation of the wild-type enhancer by ectopic Tinman protein confirms Sur is a direct target of Tinman transcriptional activation. These findings delineate at the molecular level specific sub-types of Tin cardial cells, and define an important regulatory pathway between two Drosophila genes for which mutations in human homologs have been shown to result in cardiac disease.
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26
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Cardiac Development: Toward a Molecular Basis for Congenital Heart Disease. CARDIOVASCULAR MEDICINE 2007. [DOI: 10.1007/978-1-84628-715-2_52] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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27
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Abstract
The African clawed frog, Xenopus laevis, is a valuable model system for studies of vertebrate heart development. In the following review, we describe a range of embryological and molecular methodologies that are used in Xenopus research and discuss key discoveries relating to heart development that have been made using this model system. We also discuss how the sequence of the Xenopus tropicalis genome provides a valuable tool for identification of orthologous genes and for identification of evolutionarily conserved promoter elements. Finally, both forward and reverse genetic approaches are currently being applied to Xenopus for the study of vertebrate heart development.
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Affiliation(s)
- Andrew S Warkman
- Department of Cell Biology and Anatomy, University of Arizona Health Sciences Center, 1501 N. Campbell Avenue, P.O. Box 245044, Tucson, AZ 85724, USA.
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Allen BG, Allen-Brady K, Weeks DL. Reduction of XNkx2-10 expression leads to anterior defects and malformation of the embryonic heart. Mech Dev 2006; 123:719-29. [PMID: 16949797 PMCID: PMC2094041 DOI: 10.1016/j.mod.2006.07.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2006] [Revised: 07/11/2006] [Accepted: 07/23/2006] [Indexed: 10/24/2022]
Abstract
Normal vertebrate heart development depends upon the expression of homeodomain containing proteins related to the Drosophila gene, tinman. In Xenopus laevis, three such genes have been identified in regions that will eventually give rise to the heart, XNkx2-3, XNkx2-5 and XNkx2-10. Although the expression domains of all three overlap in early development, distinctive differences have been noted. By the time the heart tube forms, there is little XNkx2-10 mRNA detected by in situ analysis in the embryonic heart while both XNkx2-3 and XNkx2-5 are clearly present. In addition, unlike XNkx2-3 and XNkx2-5, injection of XNkx2-10 mRNA does not increase the size of the embryonic heart. We have reexamined the expression and potential role of XNkx2-10 in development via oligonucleotide-mediated reduction of XNkx2-10 protein expression. We find that a decrease in XNkx2-10 leads to a broad spectrum of developmental abnormalities including a reduction in heart size. We conclude that XNkx2-10, like XNkx2-3 and XNkx2-5, is necessary for normal Xenopus heart development.
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Affiliation(s)
- Bryan G. Allen
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Kristina Allen-Brady
- Department of Biomedical Informatics, University of Utah, Salt Lake City, UT 84108, USA
| | - Daniel L. Weeks
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
- * Corresponding author. Tel: +1 319 335 7918; fax: +1 319 335 9570. E-mail address: (D.L. Weeks)
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29
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Abstract
Although there have been important advances in diagnostic modalities and therapeutic strategies for congenital heart defects (CHD), these malformations still lead to significant morbidity and mortality in the human population. Over the past 10 years, characterization of the genetic causes of CHD has begun to elucidate some of the molecular causes of these defects. Linkage analysis and candidate-gene approaches have been used to identify gene mutations that are associated with both familial and sporadic cases of CHD. Complementation of the human studies with developmental studies in mouse models provides information for the roles of these genes in normal development as well as indications for disease pathogenesis. Biochemical analysis of these gene mutations has provided further insight into the molecular effects of these genetic mutations. Here we review genetic, developmental, and biochemical studies of six cardiac transcription factors that have been identified as genetic causes for CHD in humans.
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Affiliation(s)
- Krista L Clark
- Division of Cardiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA.
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30
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Elliott DA, Solloway MJ, Wise N, Biben C, Costa MW, Furtado MB, Lange M, Dunwoodie S, Harvey RP. A tyrosine-rich domain within homeodomain transcription factor Nkx2-5 is an essential element in the early cardiac transcriptional regulatory machinery. Development 2006; 133:1311-22. [PMID: 16510504 DOI: 10.1242/dev.02305] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Homeodomain factor Nkx2-5 is a central component of the transcription factor network that guides cardiac development; in humans, mutations in NKX2.5 lead to congenital heart disease (CHD). We have genetically defined a novel conserved tyrosine-rich domain (YRD) within Nkx2-5 that has co-evolved with its homeodomain. Mutation of the YRD did not affect DNA binding and only slightly diminished transcriptional activity of Nkx2-5 in a context-specific manner in vitro. However, the YRD was absolutely essential for the function of Nkx2-5 in cardiogenesis during ES cell differentiation and in the developing embryo. Furthermore, heterozygous mutation of all nine tyrosines to alanine created an allele with a strong dominant-negative-like activity in vivo: ES cell<-->embryo chimaeras bearing the heterozygous mutation died before term with cardiac malformations similar to the more severe anomalies seen in NKX2.5 mutant families. These studies suggest a functional interdependence between the NK2 class homeodomain and YRD in cardiac development and evolution, and establish a new model for analysis of Nkx2-5 function in CHD.
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MESH Headings
- Amino Acid Sequence
- Animals
- Animals, Newborn
- Blotting, Western
- Cell Line
- Cells, Cultured
- Cephalopoda
- Conserved Sequence
- Electrophoretic Mobility Shift Assay
- Embryo, Mammalian
- Embryo, Nonmammalian
- Gene Expression Regulation, Developmental
- Gene Targeting
- Genes, Reporter
- Glutathione Transferase/metabolism
- Green Fluorescent Proteins/metabolism
- Heterozygote
- Homeobox Protein Nkx-2.5
- Homeodomain Proteins/chemistry
- Homeodomain Proteins/genetics
- Homeodomain Proteins/metabolism
- In Situ Hybridization
- Luciferases/metabolism
- Mice
- Molecular Sequence Data
- Mutation
- Myocardium/cytology
- Myocardium/metabolism
- Myocardium/pathology
- Myocytes, Cardiac/cytology
- Myocytes, Cardiac/metabolism
- Phylogeny
- Protein Structure, Tertiary
- Recombinant Fusion Proteins/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Homology, Amino Acid
- Transcription Factors/chemistry
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Transcription, Genetic
- Transcriptional Activation
- Tyrosine/chemistry
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Affiliation(s)
- David A Elliott
- Victor Chang Cardiac Research Institute, Darlinghurst, Sydney 2010, Australia
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31
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Harris BS, Spruill L, Edmonson AM, Rackley MS, Benson DW, O’Brien TX, Gourdie RG. Differentiation of cardiac Purkinje fibers requires precise spatiotemporal regulation of Nkx2-5 expression. Dev Dyn 2006; 235:38-49. [PMID: 16245335 PMCID: PMC2610391 DOI: 10.1002/dvdy.20580] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Nkx2-5 gene mutations cause cardiac abnormalities, including deficits of function in the atrioventricular conduction system (AVCS). In the chick, Nkx2-5 is elevated in Purkinje fiber AVCS cells relative to working cardiomyocytes. Here, we show that Nkx2-5 expression rises to a peak as Purkinje fibers progressively differentiate. To disrupt this pattern, we overexpressed Nkx2-5 from embryonic day 10, as Purkinje fibers are recruited within developing chick hearts. Overexpression of Nkx2-5 caused inhibition of slow tonic myosin heavy chain protein (sMHC), a late Purkinje fiber marker but did not affect Cx40 levels. Working cardiomyocytes overexpressing Nkx2-5 in these hearts ectopically up-regulated Cx40 but not sMHC. Isolated embryonic cardiomyocytes overexpressing Nkx2-5 also displayed increased Cx40 and suppressed sMHC. By contrast, overexpression of a human NKX2-5 mutant did not effect these markers in vivo or in vitro, suggesting one possible mechanism for clinical phenotypes. We conclude that a prerequisite for normal Purkinje fiber maturation is precise regulation of Nkx2-5 levels.
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Affiliation(s)
- Brett S. Harris
- Departments of Cell Biology and Anatomy, Medical University of South Carolina, Charleston SC
- Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston SC
| | - Laura Spruill
- Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston SC
| | - Angela M. Edmonson
- Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston SC
- Medical Research Service, Ralph H. Johnson Department of Veteran Affairs Medical Center, Medical University of South Carolina, Charleston SC
| | - Mary S. Rackley
- Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston SC
- Medical Research Service, Ralph H. Johnson Department of Veteran Affairs Medical Center, Medical University of South Carolina, Charleston SC
| | - D. Woodrow Benson
- Department of Molecular and Cardiovascular Biology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
| | - Terrence X. O’Brien
- Gazes Cardiac Research Institute, Medical University of South Carolina, Charleston SC
- Medical Research Service, Ralph H. Johnson Department of Veteran Affairs Medical Center, Medical University of South Carolina, Charleston SC
| | - Robert G. Gourdie
- Departments of Cell Biology and Anatomy, Medical University of South Carolina, Charleston SC
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32
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Abstract
Congenital heart disease remains a significant cause of morbidity and mortality. In recent years, significant advances in molecular genetics, improved understanding of morphogenesis, recognition of specific patterning of abnormalities within and between species, and the impact of the Human Genome Project have accounted for these advances. Continued rapid developments in genomics and proteomics are anticipated. Epidemiologic investigations continue to be necessary to assess the influence of the environment on genetics. We are on the threshold of influencing the occurrence of congenital heart diseases.
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Affiliation(s)
- Andrew N Pelech
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, PO Box 26509, 8701 Watertown Plank Road, Milwaukee, WI 53266-0509, USA.
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33
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Akazawa H, Komuro I. Cardiac transcription factor Csx/Nkx2-5: Its role in cardiac development and diseases. Pharmacol Ther 2005; 107:252-68. [PMID: 15925411 DOI: 10.1016/j.pharmthera.2005.03.005] [Citation(s) in RCA: 156] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/17/2005] [Indexed: 11/20/2022]
Abstract
During the past decade, an emerging body of evidence has accumulated that cardiac transcription factors control a cardiac gene program and play a critical role in transcriptional regulation during cardiogenesis and during the adaptive process in adult hearts. Especially, an evolutionally conserved homeobox transcription factor Csx/Nkx2-5 has been in the forefront in the field of cardiac biology, providing molecular insights into the mechanisms of cardiac development and diseases. Csx/Nkx2-5 is indispensable for normal cardiac development, and mutations of the gene are associated with human congenital heart diseases (CHD). In the present review, the regulation of a cardiac gene program by Csx/Nkx2-5 is summarized, with an emphasis on its role in the cardiac development and diseases.
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Affiliation(s)
- Hiroshi Akazawa
- Division of Cardiovascular Pathophysiology and Department of Cardiovascular Science and Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan
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34
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Abstract
Thanks to their transparent and rapidly developing mosaic embryos, ascidians (or sea squirts) have been a model system for embryological studies for over a century. Recently, ascidians have entered the postgenomic era, with the sequencing of the Ciona intestinalis genome and the accumulation of molecular resources that rival those available for fruit flies and mice. One strength of ascidians as a model system is their close similarity to vertebrates. Literature reporting molecular homologies between vertebrate and ascidian tissues has flourished over the past 15 years, since the first ascidian genes were cloned. However, it should not be forgotten that ascidians diverged from the lineage leading to vertebrates over 500 million years ago. Here, we review the main similarities and differences so far identified, at the molecular level, between ascidian and vertebrate tissues and discuss the evolution of the compact ascidian genome.
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Affiliation(s)
- Yale J Passamaneck
- Department of Cell and Developmental Biology, Weill Medical College of Cornell University, 1300 York Avenue, New York, NY 10021, USA.
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35
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Affiliation(s)
- Jau-Nian Chen
- University of California Los Angeles, Los Angeles, CA, USA
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36
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Hobbs CA, Cleves MA, Keith C, Ghaffar S, James SJ. NKX2.5 and congenital heart defects: A population-based study. Am J Med Genet A 2005; 134A:223-5. [PMID: 15633194 DOI: 10.1002/ajmg.a.30509] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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37
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Han Z, Olson EN. Hand is a direct target of Tinman and GATA factors during Drosophila cardiogenesis and hematopoiesis. Development 2005; 132:3525-36. [PMID: 15975941 DOI: 10.1242/dev.01899] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The existence of hemangioblasts, which serve as common progenitors for hematopoietic cells and cardioblasts, has suggested a molecular link between cardiogenesis and hematopoiesis in Drosophila. However, the molecular mediators that might link hematopoiesis and cardiogenesis remain unknown. Here, we show that the highly conserved basic helix-loop-helix (bHLH) transcription factor Hand is expressed in cardioblasts, pericardial nephrocytes and hematopoietic progenitors. The homeodomain protein Tinman and the GATA factors Pannier and Serpent directly activate Hand in these cell types through a minimal enhancer, which is necessary and sufficient to drive Hand expression in these different cell types. Hand is activated by Tinman and Pannier in cardioblasts and pericardial nephrocytes, and by Serpent in hematopoietic progenitors in the lymph gland. These findings place Hand at a nexus of the transcriptional networks that govern cardiogenesis and hematopoiesis, and indicate that the transcriptional pathways involved in development of the cardiovascular, excretory and hematopoietic systems may be more closely related than previously appreciated.
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Affiliation(s)
- Zhe Han
- Department of Molecular Biology, University of Texas Southwestern Medical Center at Dallas, 6000 Harry Hines Boulevard, Dallas, TX 75390, USA
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38
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Ma CM. Spatial and temporal expression patterns of Xenopus Nkx-2.3 gene in skin epidermis during metamorphosis. Gene Expr Patterns 2005; 5:129-34. [PMID: 15533828 DOI: 10.1016/j.modgep.2004.05.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2004] [Revised: 05/18/2004] [Accepted: 05/18/2004] [Indexed: 11/20/2022]
Abstract
Using PCR cloning, the mRNA of XNkx-2.3 gene, a Xenopus tinman homologue, was identified in a cDNA library prepared from thyroid hormone (T(3))-treated tadpole skin. Quantitative RT-PCR and RNase Protection Assay confirmed the expression of XNkx-2.3 in adult frog skin and its amount was similar to the amount found in heart. In situ hybridization indicated that XNkx-2.3 was expressed in the frog epidermis. Further analysis of XNkx-2.3 expression patterns demonstrates that it shares great similarities with a 63 kDa keratin, a well-characterized marker for skin maturation, in the following aspects. First, XNkx-2.3 was expressed in tadpole skin during metamorphosis (stages 55-59), but not in pre-metamorphic (stage 54) skin. Secondly, XNkx-2.3 expression in skin responded to T(3) stimulation because it could be precociously induced by T(3) at pre-metamorphic stage, both in tadpoles and in cultures of skin explants. Finally, the T(3)-induced appearance of XNkx-2.3 in head skin occurred earlier and at higher level than that in tail skin. These data suggest that XNkx-2.3 may be an important factor for skin maturation and may also serve as a good marker to indicate the maturation of Xenopus epidermis.
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Affiliation(s)
- Chang M Ma
- Laboratory of Mammalian Genes and Development, National Institute of Child Health and Development, National Institute of Health, 2B211, Bldg. 6B, 9000 Rockville Pike, Bethesda, MD 20892, USA.
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39
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Brott BK, Sokol SY. A Vertebrate Homolog of the Cell Cycle Regulator Dbf4 Is an Inhibitor of Wnt Signaling Required for Heart Development. Dev Cell 2005; 8:703-15. [PMID: 15866161 DOI: 10.1016/j.devcel.2005.02.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2004] [Revised: 01/24/2005] [Accepted: 02/11/2005] [Indexed: 11/21/2022]
Abstract
Early stages of vertebrate heart development have been linked to Wnt signaling. Here we show in both gain- and loss-of-function experiments that XDbf4, a known regulator of Cdc7 kinase, is an inhibitor of the canonical Wnt signaling pathway. Depletion of endogenous XDbf4 protein did not disturb gastrulation movements or early organizer genes but resulted in embryos with morphologically defective heart and eyes and suppressed cardiac markers. These markers were restored by overexpressed XDbf4, or an XDbf4 mutant that inhibits Wnt signaling but lacks the ability to regulate Cdc7. This indicates that the function of XDbf4 in heart development is independent of its role in the cell cycle. Moreover, our data suggest that XDbf4 acts through the physical and functional interaction with Frodo, a context-dependent regulator of Wnt signaling. These findings establish an unexpected function for a vertebrate Dbf4 homolog and demonstrate the requirement for Wnt inhibition in early cardiac specification.
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Affiliation(s)
- Barbara K Brott
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02215, USA
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40
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Ryan K, Russ AP, Levy RJ, Wehr DJ, You J, Easterday MC. Modulation of eomes activity alters the size of the developing heart: implications for in utero cardiac gene therapy. Hum Gene Ther 2004; 15:842-55. [PMID: 15353039 DOI: 10.1089/hum.2004.15.842] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Congenital heart disease is the most prevalent cause of infant morbidity and mortality in developed countries. The mechanisms responsible for many specific types of congenital cardiac malformations are strongly associated with gene abnormalities. However, at this time no strategies for gene therapy of the various congenital heart malformations have been investigated. In the present studies we focus on Eomesodermin (Eomes), a T-box transcription factor expressed in developing vertebrate mesoderm. Although Eomes is required for early mesodermal patterning and differentiation, the role of Eomes in cardiac development is unknown. In the present studies we demonstrate that Eomes is expressed in the developing heart, with a pronounced myocardial distribution in the Xenopus ventricle during late cardiac development. Using either a conditional dominant-interfering approach (GR-Eomes--engrailed) or an Eomes-activating approach (GR-Eomes-VP16) we demonstrate that manipulating Eomes activity during late cardiac development can either suppress ventricular development (GR-Eomes-enR) or increase ventricular myocardial size (GR-Eomes-VP16). Thus, a potential gene therapy approach for treating both congenital ventricular hypoplasia (e.g., the hypoplastic left heart syndrome) and hypertrophic cardiomyopathy is hypothetically implicit from the present results.
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Affiliation(s)
- Kenneth Ryan
- Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Joseph Stokes Jr. Research Institute, Division of Cardiology, Abramson Research Center, Philadelphia, PA 19104-4318, USA.
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41
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Harris BS, Jay PY, Rackley MS, Izumo S, O'brien TX, Gourdie RG. Transcriptional regulation of cardiac conduction system development: 2004 FASEB cardiac conduction system minimeeting, Washington, DC. ACTA ACUST UNITED AC 2004; 280:1036-45. [PMID: 15368344 DOI: 10.1002/ar.a.20101] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The development of the complex network of specialized cells that form the atrioventricular conduction system (AVCS) during cardiac morphogenesis occurs by progressive recruitment within a multipotent cardiomyogenic lineage. Understanding the molecular control of this developmental process has been the focus of recent research. Transcription factors representative of multiple subfamilies have been identified and include members of zinc-finger subfamilies (GATA4, GATA6 HF-1b), skeletal muscle transcription factors (MyoD), T-box genes (Tbx5), and also homeodomain transcription factors (Msx2 and Nkx2.5). Mutations in some of these transcription factors cause congenital heart disease and are associated with cardiac abnormalities, including deficits within the AVCS. Mouse models that closely phenocopy known human heart disease provide powerful tools for the study of molecular effectors of AVCS development. Indeed, investigations of the Nkx2.5 haploinsufficient mouse have shown that peripheral Purkinje fibers are significantly underrepresented. This piece of data corroborates our previous work showing in chick, mouse, and humans that Nkx2.5 is elevated in the differentiating AVCS relative to adjacent working ventricular myocardial tissues. Using the chick embryo as a model, we show that this elevation of Nkx2.5 is transient in the network of conduction cells comprising the peripheral Purkinje fiber system. Functional studies using defective adenoviral constructs, which disrupt the normal variation in level of this gene, result in perturbations of Purkinje fiber phenotype. Thus, the precise spatiotemporal regulation of Nkx2.5 levels during development may be required for the progressive emergence of gene expression patterns specific to differentiated Purkinje fiber cells.
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Affiliation(s)
- Brett S Harris
- Department of Cell Biology and Anatomy, Medical University of South Carolina, Charleston, SC 29425, USA.
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42
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Stennard FA, Costa MW, Elliott DA, Rankin S, Haast SJP, Lai D, McDonald LPA, Niederreither K, Dolle P, Bruneau BG, Zorn AM, Harvey RP. Cardiac T-box factor Tbx20 directly interacts with Nkx2-5, GATA4, and GATA5 in regulation of gene expression in the developing heart. Dev Biol 2003; 262:206-24. [PMID: 14550786 DOI: 10.1016/s0012-1606(03)00385-3] [Citation(s) in RCA: 214] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Tbx20 is a member of the T-box transcription factor family expressed in the forming hearts of vertebrate and invertebrate embryos. We report here analysis of Tbx20 expression during murine cardiac development and assessment of DNA-binding and transcriptional properties of Tbx20 isoforms. Tbx20 was expressed in myocardium and endocardium, including high levels in endocardial cushions. cDNAs generated by alternative splicing encode at least four Tbx20 isoforms, and Tbx20a uniquely carried strong transactivation and transrepression domains in its C terminus. Isoforms with an intact T-box bound specifically to DNA sites resembling the consensus brachyury half site, although with less avidity compared with the related factor, Tbx5. Tbx20 physically interacted with cardiac transcription factors Nkx2-5, GATA4, and GATA5, collaborating to synergistically activate cardiac gene expression. Among cardiac GATA factors, there was preferential synergy with GATA5, implicated in endocardial differentiation. In Xenopus embryos, enforced expression of Tbx20a, but not Tbx20b, led to induction of mesodermal and endodermal lineage markers as well as cell migration, indicating that the long Tbx20a isoform uniquely bears functional domains that can alter gene expression and developmental behaviour in an in vivo context. We propose that Tbx20 plays an integrated role in the ancient myogenic program of the heart, and has been additionally coopted during evolution of vertebrates for endocardial cushion development.
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Affiliation(s)
- Fiona A Stennard
- Victor Chang Cardiac Research Institute, 384 Victoria Street, Darlinghurst, 2010, Sydney, Australia
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43
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Moorman AFM, Christoffels VM. Cardiac chamber formation: development, genes, and evolution. Physiol Rev 2003; 83:1223-67. [PMID: 14506305 DOI: 10.1152/physrev.00006.2003] [Citation(s) in RCA: 455] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Concepts of cardiac development have greatly influenced the description of the formation of the four-chambered vertebrate heart. Traditionally, the embryonic tubular heart is considered to be a composite of serially arranged segments representing adult cardiac compartments. Conversion of such a serial arrangement into the parallel arrangement of the mammalian heart is difficult to understand. Logical integration of the development of the cardiac conduction system into the serial concept has remained puzzling as well. Therefore, the current description needed reconsideration, and we decided to evaluate the essentialities of cardiac design, its evolutionary and embryonic development, and the molecular pathways recruited to make the four-chambered mammalian heart. The three principal notions taken into consideration are as follows. 1) Both the ancestor chordate heart and the embryonic tubular heart of higher vertebrates consist of poorly developed and poorly coupled "pacemaker-like" cardiac muscle cells with the highest pacemaker activity at the venous pole, causing unidirectional peristaltic contraction waves. 2) From this heart tube, ventricular chambers differentiate ventrally and atrial chambers dorsally. The developing chambers display high proliferative activity and consist of structurally well-developed and well-coupled muscle cells with low pacemaker activity, which permits fast conduction of the impulse and efficacious contraction. The forming chambers remain flanked by slowly proliferating pacemaker-like myocardium that is temporally prevented from differentiating into chamber myocardium. 3) The trabecular myocardium proliferates slowly, consists of structurally poorly developed, but well-coupled, cells and contributes to the ventricular conduction system. The atrial and ventricular chambers of the formed heart are activated and interconnected by derivatives of embryonic myocardium. The topographical arrangement of the distinct cardiac muscle cells in the forming heart explains the embryonic electrocardiogram (ECG), does not require the invention of nodes, and allows a logical transition from a peristaltic tubular heart to a synchronously contracting four-chambered heart. This view on the development of cardiac design unfolds fascinating possibilities for future research.
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Affiliation(s)
- Antoon F M Moorman
- Department of Anatomy & Embryology, Academic Medical Center, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands.
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44
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Peterkin T, Gibson A, Patient R. GATA-6 maintains BMP-4 and Nkx2 expression during cardiomyocyte precursor maturation. EMBO J 2003; 22:4260-73. [PMID: 12912923 PMCID: PMC175790 DOI: 10.1093/emboj/cdg400] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
GATA-6 is expressed in presumptive cardiac mesoderm before gastrulation, but its role in heart development has been unclear. Here we show that Xenopus and zebrafish embryos, injected with antisense morpholino oligonucleotides designed specifically to knock-down translation of GATA-6 protein, are severely compromised for heart development. Injected embryos express greatly reduced levels of contractile machinery genes and, at the same stage, of regulatory genes such as bone morphogenetic protein-4 (BMP-4) and the Nkx2 family. In contrast, initial BMP and Nkx2 expression is normal, suggesting a maintenance role for GATA-6. Endoderm is critical for heart formation in several vertebrates including Xenopus, and separate perturbation of GATA-6 expression in the deep anterior endoderm and in the overlying heart mesoderm shows that GATA-6 is required in both for cardiogenesis. The GATA-6 requirement in cardiac mesoderm was confirmed in zebrafish, an organism in which endoderm is thought not to be necessary for heart formation. We therefore conclude that proper maturation of cardiac mesoderm requires GATA-6, which functions to maintain BMP-4 and Nkx2 expression.
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Affiliation(s)
- Tessa Peterkin
- Institute of Genetics, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK
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45
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Dentice M, Morisco C, Vitale M, Rossi G, Fenzi G, Salvatore D. The different cardiac expression of the type 2 iodothyronine deiodinase gene between human and rat is related to the differential response of the Dio2 genes to Nkx-2.5 and GATA-4 transcription factors. Mol Endocrinol 2003; 17:1508-21. [PMID: 12775767 DOI: 10.1210/me.2002-0348] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
By producing T3 from T4, type 2 iodothyronine deiodinase (D2) catalyzes the first step in the cascade underlying the effect exerted by thyroid hormone. Type 2 iodothyronine deiodinase mRNA is expressed at high levels in human heart but is barely detectable in the corresponding rodent tissue. Although the heart is a major target of thyroid hormone, the role of cardiac D2 and the factors that regulate its expression are unknown. Here we report that the human Dio2 promoter is very sensitive to the cardiac transcription factors Nkx-2.5 and GATA-4. Nkx-2.5 transactivates a 6.5-kb human (h)Dio2-chloramphenicol acetyltransferase construct, with maximal induction reached with a 633-bp proximal promoter region. Interestingly, despite 73% identity with the corresponding human region, the rat Dio2 promoter is much less responsive to Nkx-2.5 induction. Using EMSA, we found that two sites in the human promoter (C and D) specifically bind Nkx-2.5. In coexpression studies, GATA-4 alone was a poor inducer of the hDio2 promoter; however in synergy with Nkx-2.5, it activated D2 reporter gene expression in the human, but not the rat promoter. Functional analysis showed that both C and D sites are required for the complete Nkx-2.5 response and for the Nkx-2.5/GATA-4 synergistic effect. In neonatal rat primary myocardiocytes, most of the hDio2-chloramphenicol acetyltransferase activity was suppressed by mutation of the Nkx-2.5 binding sites. Finally, a mutant Nkx-2.5 protein (N188K), which causes, in heterozygosity, congenital heart diseases, did not transactivate the Dio2 promoter and interfered with its activity in cardiomyocytes, possibly by titrating endogenous Nkx-2.5 protein away from the promoter. In conclusion, this study shows that Nkx-2.5 and GATA-4 play prime roles in Dio2 gene regulation in the human heart and suggests that it is their synergistic action in humans that causes the differential expression of the cardiac Dio2 gene between humans and rats.
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Affiliation(s)
- Monica Dentice
- Dipartimento di Biologia e Pathologia Cellulare e Molecolare, Facolta di Medicina e Chirurgia, Universita degli Studi di Napoli "Federico II," 80131 Naples, Italy
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46
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Abstract
The heart develops from two bilateral heart fields that are formed during early gastrulation. In recent years, signaling pathways that specify cardiac mesoderm have been extensively analyzed. In addition, a battery of transcription factors that regulate different aspects of cardiac morphogenesis and cytodifferentiation have been identified and characterized in model organisms. At the anterior pole, a secondary heart field is formed, which in its molecular make-up, appears to be similar to the primary heart field. The cardiac outflow tract and the right ventricle to a large extent are derivatives of this anterior heart field. Cardiac mesoderm receives positional information by which it is patterned along the three body axes. The molecular control of left-right axis development has received particular attention, and the underlying regulatory network begins to emerge. Cardiac chamber development involves the activation of a transcription program that is different from the one present in the primary heart field and regulates cardiac morphogenesis in a region-specific manner. This review also attempts to identify areas in which additional research is needed to fully understand early cardiac development.
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Affiliation(s)
- Thomas Brand
- Department of Cell and Molecular Biology, Technical University of Braunschweig, 38106 Braunschweig, Germany.
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47
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Brand T, Andrée B, Schlange T. Molecular characterization of early cardiac development. Results Probl Cell Differ 2003; 38:215-38. [PMID: 12132397 DOI: 10.1007/978-3-540-45686-5_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Affiliation(s)
- Thomas Brand
- Institute of Biochemistry and Biotechnology, Department of Cell and Molecular Biology, Technical University of Braunschweig, Spielmannstr. 7, 38106 Braunschweig, Germany
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48
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Abstract
The heart is the first organ to form during embryogenesis and its circulatory function is critical from early on for the viability of the mammalian embryo. Developmental abnormalities of the heart have also been widely recognized as the underlying cause of many congenital heart malformations. Hence, the developmental mechanisms that orchestrate the formation and morphogenesis of this organ have received much attention among classical and molecular embryologists. Due to the evolutionary conservation of many of these processes, major insights have been gained from the studies of a number of vertebrate and invertebrate models, including mouse, chick, amphibians, zebrafish, and Drosophila. In all of these systems, the heart precursors are generated within bilateral fields in the lateral mesoderm and then converge toward the midline to form a beating linear heart tube. The specification of heart precursors is a result of multiple tissue and cell-cell interactions that involve temporally and spatially integrated programs of inductive signaling events. In the present review, we focus on the molecular and developmental functions of signaling processes during early cardiogenesis that have been defined in both vertebrate and invertebrate models. We discuss the current knowledge on the mechanisms through which signals induce the expression of cardiogenic transcription factors and the relationships between signaling pathways and transcriptional regulators that cooperate to control cardiac induction and the formation of a linear heart tube.
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Affiliation(s)
- Stéphane Zaffran
- Mount Sinai School of Medicine, Brookdale Department of Molecular, Cell and Developmental Biology, New York, NY 10029, USA
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Shirai M, Osugi T, Koga H, Kaji Y, Takimoto E, Komuro I, Hara J, Miwa T, Yamauchi-Takihara K, Takihara Y. The Polycomb-group gene Rae28 sustains Nkx2.5/Csx expression and is essential for cardiac morphogenesis. J Clin Invest 2002. [DOI: 10.1172/jci0214839] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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50
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Shirai M, Osugi T, Koga H, Kaji Y, Takimoto E, Komuro I, Hara J, Miwa T, Yamauchi-Takihara K, Takihara Y. The Polycomb-group gene Rae28 sustains Nkx2.5/Csx expression and is essential for cardiac morphogenesis. J Clin Invest 2002; 110:177-84. [PMID: 12122109 PMCID: PMC151044 DOI: 10.1172/jci14839] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The Polycomb-group (PcG) gene Rae28 is a mammalian homologue of the Drosophila gene polyhomeotic. PcG genes are known to maintain transcription states, once initiated, probably by regulating chromatin structure. Since homozygous Rae28-deficient (Rae28(-/-)) mice displayed cardiac anomalies similar to congenital heart diseases in humans, we examined the role of Rae28 in cardiac morphogenesis at the molecular level. In Rae28(-/-) embryos, expression of the cardiac selector gene Nkx2.5/Csx (Nkx2.5) was initiated properly but was not sufficiently sustained later in development. This impaired expression of Nkx2.5 in the maintenance phase proved to have a crucial effect on cardiac morphogenesis, as demonstrated by the results of a genetic complementation experiment in which the cardiac anomalies were suppressed by overexpression of human NKX2.5/CSX1 in Rae28(-/-) embryos. Ubiquitous expression of exogenous Rae28 likewise restored the impaired Nkx2.5 expression in Rae28(-/-) embryos, further supporting the notion that Rae28 sustains Nkx2.5 expression in cardiomyocytes. Thus, our data show that a mammalian PcG gene can play a key role in organogenesis by helping to maintain the expression of a selector gene.
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Affiliation(s)
- Manabu Shirai
- Department of Developmental Biology and Medicine, Osaka Medical Center for Cancer and Cardiovascular Diseases, Higashinari, Japan
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