1
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Exploring the Mutational Landscape of Isolated Congenital Heart Defects: An Exome Sequencing Study Using Cardiac DNA. Genes (Basel) 2022; 13:genes13071214. [PMID: 35885997 PMCID: PMC9320903 DOI: 10.3390/genes13071214] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 07/02/2022] [Accepted: 07/04/2022] [Indexed: 11/17/2022] Open
Abstract
Congenital heart defects (CHD) are the most common congenital anomalies in liveborn children. In contrast to syndromic CHD (SCHD), the genetic basis of isolated CHD (ICHD) is complex, and the underlying pathogenic mechanisms appear intricate and are incompletely understood. Next to rare Mendelian conditions, somatic mosaicism or a complex multifactorial genetic architecture are assumed for most ICHD. We performed exome sequencing (ES) in 73 parent–offspring ICHD trios using proband DNA extracted from cardiac tissue. We identified six germline de novo variants and 625 germline rare inherited variants with ‘damaging’ in silico predictions in cardiac-relevant genes expressed in the developing human heart. There were no CHD-relevant somatic variants. Transmission disequilibrium testing (TDT) and association testing (AT) yielded no statistically significant results, except for the AT of missense variants in cilia genes. Somatic mutations are not a common cause of ICHD. Rare de novo and inherited protein-damaging variants may contribute to ICHD, possibly as part of an oligogenic or polygenic disease model. TDT and AT failed to provide informative results, likely due to the lack of power, but provided a framework for future studies in larger cohorts. Overall, the diagnostic value of ES on cardiac tissue is limited in individual ICHD cases.
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2
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Signaling pathways and targeted therapy for myocardial infarction. Signal Transduct Target Ther 2022; 7:78. [PMID: 35273164 PMCID: PMC8913803 DOI: 10.1038/s41392-022-00925-z] [Citation(s) in RCA: 225] [Impact Index Per Article: 112.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 01/28/2022] [Accepted: 02/08/2022] [Indexed: 02/07/2023] Open
Abstract
Although the treatment of myocardial infarction (MI) has improved considerably, it is still a worldwide disease with high morbidity and high mortality. Whilst there is still a long way to go for discovering ideal treatments, therapeutic strategies committed to cardioprotection and cardiac repair following cardiac ischemia are emerging. Evidence of pathological characteristics in MI illustrates cell signaling pathways that participate in the survival, proliferation, apoptosis, autophagy of cardiomyocytes, endothelial cells, fibroblasts, monocytes, and stem cells. These signaling pathways include the key players in inflammation response, e.g., NLRP3/caspase-1 and TLR4/MyD88/NF-κB; the crucial mediators in oxidative stress and apoptosis, for instance, Notch, Hippo/YAP, RhoA/ROCK, Nrf2/HO-1, and Sonic hedgehog; the controller of myocardial fibrosis such as TGF-β/SMADs and Wnt/β-catenin; and the main regulator of angiogenesis, PI3K/Akt, MAPK, JAK/STAT, Sonic hedgehog, etc. Since signaling pathways play an important role in administering the process of MI, aiming at targeting these aberrant signaling pathways and improving the pathological manifestations in MI is indispensable and promising. Hence, drug therapy, gene therapy, protein therapy, cell therapy, and exosome therapy have been emerging and are known as novel therapies. In this review, we summarize the therapeutic strategies for MI by regulating these associated pathways, which contribute to inhibiting cardiomyocytes death, attenuating inflammation, enhancing angiogenesis, etc. so as to repair and re-functionalize damaged hearts.
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3
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Shewale B, Dubois N. Of form and function: Early cardiac morphogenesis across classical and emerging model systems. Semin Cell Dev Biol 2021; 118:107-118. [PMID: 33994301 PMCID: PMC8434962 DOI: 10.1016/j.semcdb.2021.04.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 04/27/2021] [Accepted: 04/28/2021] [Indexed: 12/31/2022]
Abstract
The heart is the earliest organ to develop during embryogenesis and is remarkable in its ability to function efficiently as it is being sculpted. Cardiac heart defects account for a high burden of childhood developmental disorders with many remaining poorly understood mechanistically. Decades of work across a multitude of model organisms has informed our understanding of early cardiac differentiation and morphogenesis and has simultaneously opened new and unanswered questions. Here we have synthesized current knowledge in the field and reviewed recent developments in the realm of imaging, bioengineering and genetic technology and ex vivo cardiac modeling that may be deployed to generate more holistic models of early cardiac morphogenesis, and by extension, new platforms to study congenital heart defects.
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Affiliation(s)
- Bhavana Shewale
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Nicole Dubois
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
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4
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Kilian LS, Voran J, Frank D, Rangrez AY. RhoA: a dubious molecule in cardiac pathophysiology. J Biomed Sci 2021; 28:33. [PMID: 33906663 PMCID: PMC8080415 DOI: 10.1186/s12929-021-00730-w] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 04/23/2021] [Indexed: 02/08/2023] Open
Abstract
The Ras homolog gene family member A (RhoA) is the founding member of Rho GTPase superfamily originally studied in cancer cells where it was found to stimulate cell cycle progression and migration. RhoA acts as a master switch control of actin dynamics essential for maintaining cytoarchitecture of a cell. In the last two decades, however, RhoA has been coined and increasingly investigated as an essential molecule involved in signal transduction and regulation of gene transcription thereby affecting physiological functions such as cell division, survival, proliferation and migration. RhoA has been shown to play an important role in cardiac remodeling and cardiomyopathies; underlying mechanisms are however still poorly understood since the results derived from in vitro and in vivo experiments are still inconclusive. Interestingly its role in the development of cardiomyopathies or heart failure remains largely unclear due to anomalies in the current data available that indicate both cardioprotective and deleterious effects. In this review, we aimed to outline the molecular mechanisms of RhoA activation, to give an overview of its regulators, and the probable mechanisms of signal transduction leading to RhoA activation and induction of downstream effector pathways and corresponding cellular responses in cardiac (patho)physiology. Furthermore, we discuss the existing studies assessing the presented results and shedding light on the often-ambiguous data. Overall, we provide an update of the molecular, physiological and pathological functions of RhoA in the heart and its potential in cardiac therapeutics.
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Affiliation(s)
- Lucia Sophie Kilian
- Department of Internal Medicine III (Cardiology, Angiology, Intensive Care), University Medical Center Kiel, Rosalind-Franklin Str. 12, 24105, Kiel, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, 24105, Kiel, Germany
| | - Jakob Voran
- Department of Internal Medicine III (Cardiology, Angiology, Intensive Care), University Medical Center Kiel, Rosalind-Franklin Str. 12, 24105, Kiel, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, 24105, Kiel, Germany
| | - Derk Frank
- Department of Internal Medicine III (Cardiology, Angiology, Intensive Care), University Medical Center Kiel, Rosalind-Franklin Str. 12, 24105, Kiel, Germany. .,DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, 24105, Kiel, Germany.
| | - Ashraf Yusuf Rangrez
- Department of Internal Medicine III (Cardiology, Angiology, Intensive Care), University Medical Center Kiel, Rosalind-Franklin Str. 12, 24105, Kiel, Germany. .,DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, 24105, Kiel, Germany. .,Department of Cardiology, Angiology and Pneumology, University Hospital Heidelberg, Im Neuenheimer Feld 410, 69120, Heidelberg, Germany.
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5
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Vicente-Steijn R, Kelder TP, Tertoolen LG, Wisse LJ, Pijnappels DA, Poelmann RE, Schalij MJ, deRuiter MC, Gittenberger-de Groot AC, Jongbloed MRM. RHOA-ROCK signalling is necessary for lateralization and differentiation of the developing sinoatrial node. Cardiovasc Res 2018; 113:1186-1197. [PMID: 28899000 DOI: 10.1093/cvr/cvx104] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 07/03/2017] [Indexed: 01/16/2023] Open
Abstract
Aims RHOA-ROCK signalling regulates cell migration, proliferation, differentiation, and transcription. RHOA is expressed in the developing cardiac conduction system in chicken and mice. In early development, the entire sinus venosus myocardium, including both the transient left-sided and the definitive sinoatrial node (SAN), has pacemaker potential. Later, pacemaker potential is restricted to the right-sided SAN. Disruption of RHOA expression in adult mice causes arrhythmias including bradycardia and atrial fibrillation, the mechanism of which is unknown but presumed to affect the SAN. The aim of this study is to assess the role of RHOA-ROCK signalling in SAN development in the chicken heart. Methods and results ROCK signalling was inhibited chemically in embryonic chicken hearts using Y-27632. This prolonged the immature state of the sinus venosus myocardium, evidenced by up-regulation of the transcription factor ISL1, wide distribution of pacemaker potential, and significantly reduced heart rate. Furthermore ROCK inhibition caused aberrant expression of typical SAN genes: ROCK1, ROCK2, SHOX2, TBX3, TBX5, ISL1, HCN4, CX40, CAV3.1, and NKX2.5 and left-right asymmetry genes: PITX2C and NODAL. Anatomical abnormalities in pulmonary vein development were also observed. Patch clamp electrophysiology confirmed the immature phenotype of the SAN cells and a residual left-sided sinus venosus myocardium pacemaker-like potential. Conclusions RHOA-ROCK signalling is involved in establishing the right-sided SAN as the definitive pacemaker of the heart and restricts typical pacemaker gene expression to the right side of the sinus venosus myocardium.
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Affiliation(s)
- Rebecca Vicente-Steijn
- Department of Anatomy & Embryology, Leiden University Medical Center, Leiden, The Netherlands.,Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands.,ICIN Netherlands Heart Institute, Utrecht, The Netherlands
| | - Tim P Kelder
- Department of Anatomy & Embryology, Leiden University Medical Center, Leiden, The Netherlands
| | - Leon G Tertoolen
- Department of Anatomy & Embryology, Leiden University Medical Center, Leiden, The Netherlands
| | - Lambertus J Wisse
- Department of Anatomy & Embryology, Leiden University Medical Center, Leiden, The Netherlands
| | - Daniël A Pijnappels
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Robert E Poelmann
- Sylvius Laboratory, Institute of Biology Leiden (IBL), Leiden University, Leiden, The Netherlands
| | - Martin J Schalij
- Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Marco C deRuiter
- Department of Anatomy & Embryology, Leiden University Medical Center, Leiden, The Netherlands
| | - Adriana C Gittenberger-de Groot
- Department of Anatomy & Embryology, Leiden University Medical Center, Leiden, The Netherlands.,Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Monique R M Jongbloed
- Department of Anatomy & Embryology, Leiden University Medical Center, Leiden, The Netherlands.,Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
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6
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Bruche S, Zaccolo M. FRET-ting about RhoA signalling in heart and vasculature: a new tool in our cardiovascular toolbox. Cardiovasc Res 2018; 114:e25-e27. [DOI: 10.1093/cvr/cvy032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Susann Bruche
- Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, South Parks Road, Oxford OX1 3PT, UK
| | - Manuela Zaccolo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, South Parks Road, Oxford OX1 3PT, UK
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7
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Gao LR, Wang G, Zhang J, Li S, Chuai M, Bao Y, Hocher B, Yang X. High salt-induced excess reactive oxygen species production resulted in heart tube malformation during gastrulation. J Cell Physiol 2018; 233:7120-7133. [PMID: 29574800 DOI: 10.1002/jcp.26528] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Accepted: 01/31/2018] [Indexed: 12/30/2022]
Abstract
An association has been proved between high salt consumption and cardiovascular mortality. In vertebrates, the heart is the first functional organ to be formed. However, it is not clear whether high-salt exposure has an adverse impact on cardiogenesis. Here we report high-salt exposure inhibited basement membrane breakdown by affecting RhoA, thus disturbing the expression of Slug/E-cadherin/N-cadherin/Laminin and interfering with mesoderm formation during the epithelial-mesenchymal transition(EMT). Furthermore, the DiI+ cell migration trajectory in vivo and scratch wound assays in vitro indicated that high-salt exposure restricted cell migration of cardiac progenitors, which was caused by the weaker cytoskeleton structure and unaltered corresponding adhesion junctions at HH7. Besides, down-regulation of GATA4/5/6, Nkx2.5, TBX5, and Mef2c and up-regulation of Wnt3a/β-catenin caused aberrant cardiomyocyte differentiation at HH7 and HH10. High-salt exposure also inhibited cell proliferation and promoted apoptosis. Most importantly, our study revealed that excessive reactive oxygen species(ROS)generated by high salt disturbed the expression of cardiac-related genes, detrimentally affecting the above process including EMT, cell migration, differentiation, cell proliferation and apoptosis, which is the major cause of malformation of heart tubes.
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Affiliation(s)
- Lin-Rui Gao
- Division of Histology and Embryology, Joint Laboratory for Embryonic Development and Prenatal Medicine, Medical College, Jinan University, Guangzhou, China.,Key Laboratory for Regenerative Medicine of the Ministry of Education, Jinan University, Guangzhou, China
| | - Guang Wang
- Division of Histology and Embryology, Joint Laboratory for Embryonic Development and Prenatal Medicine, Medical College, Jinan University, Guangzhou, China.,Key Laboratory for Regenerative Medicine of the Ministry of Education, Jinan University, Guangzhou, China
| | - Jing Zhang
- Division of Histology and Embryology, Joint Laboratory for Embryonic Development and Prenatal Medicine, Medical College, Jinan University, Guangzhou, China
| | - Shuai Li
- Division of Histology and Embryology, Joint Laboratory for Embryonic Development and Prenatal Medicine, Medical College, Jinan University, Guangzhou, China
| | - Manli Chuai
- Division of Cell and Developmental Biology, University of Dundee, Dundee, UK
| | - Yongping Bao
- Norwich Medical School, University of East Anglia, Norwich, Norfolk, UK
| | - Berthold Hocher
- Division of Histology and Embryology, Joint Laboratory for Embryonic Development and Prenatal Medicine, Medical College, Jinan University, Guangzhou, China.,Institute of Nutritional Science, University of Potsdam, Potsdam-Nuthetal, Germany
| | - Xuesong Yang
- Division of Histology and Embryology, Joint Laboratory for Embryonic Development and Prenatal Medicine, Medical College, Jinan University, Guangzhou, China.,Key Laboratory for Regenerative Medicine of the Ministry of Education, Jinan University, Guangzhou, China
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8
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Hanovice NJ, McMains E, Gross JM. A GAL4-inducible transgenic tool kit for the in vivo modulation of Rho GTPase activity in zebrafish. Dev Dyn 2016; 245:844-53. [PMID: 27105927 PMCID: PMC4946996 DOI: 10.1002/dvdy.24412] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Revised: 03/21/2016] [Accepted: 03/29/2016] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Rho GTPases are small monomeric G-proteins that play key roles in many cellular processes. Due to Rho GTPases' widespread expression and broad functions, analyses of their function during late development require tissue-specific modulation of activity. The GAL4/UAS system provides an excellent tool for investigating the function of Rho GTPases in vivo. With this in mind, we created a transgenic tool kit enabling spatial and temporal modulation of Rho GTPase activity in zebrafish. RESULTS Transgenic constructs were assembled driving dominant-negative, constitutively active, and wild-type versions of Cdc42, RhoA, and Rac1 under 10XUAS control. The self-cleaving viral peptide F2A was utilized to allow bicistronic expression of a fluorescent reporter and Rho GTPase. Global heat shock of hsp70l:gal4(+) transgenic embryos confirmed GAL4-specific construct expression. Western blot analysis indicated myc-tagged Rho GTPases were expressed only in the presence of GAL4. Construct expression was confined to proper cells when combined with pou4f3:gal4 or ptf1a:gal4. Finally, transgene expression resulted in reproducible defects in lens formation, indicating that the transgenes are functional in vivo. CONCLUSIONS We generated and validated 10 transgenic lines, creating a versatile tool kit for the temporal-spatial modulation of Cdc42, RhoA, and Rac1 activity in vivo. These lines will enable systematic analysis of Rho GTPase function in any tissue of interest. Developmental Dynamics 245:844-853, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Nicholas J Hanovice
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas
- Department of Ophthalmology, Louis J. Fox Center for Vision Restoration, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Emily McMains
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas
| | - Jeffrey M Gross
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas
- Department of Ophthalmology, Louis J. Fox Center for Vision Restoration, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
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9
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Abstract
In past decades, growing evidence from basic and clinical researches reveal that small guanosine triphosphate binding protein ras homolog gene family, member A (RhoA) and its main effector Rho-associated kinase (ROCK) play central and complex roles in cardiovascular systems, and increasing RhoA and ROCK activity is associated with a broad range of cardiovascular diseases such as congestive heart failure, atherosclerosis, and hypertension. Favorable outcomes have been observed with ROCK inhibitors treatment. In this review, we briefly summarize the pathophysiological roles of RhoA/ROCK signaling pathway on cardiovascular system, displaying the potential benefits in the cardiovascular system with controlling RhoA/ROCK signaling pathway.
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10
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Wittig JG, Münsterberg A. The Early Stages of Heart Development: Insights from Chicken Embryos. J Cardiovasc Dev Dis 2016; 3:jcdd3020012. [PMID: 29367563 PMCID: PMC5715676 DOI: 10.3390/jcdd3020012] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 03/28/2016] [Accepted: 03/30/2016] [Indexed: 01/01/2023] Open
Abstract
The heart is the first functioning organ in the developing embryo and a detailed understanding of the molecular and cellular mechanisms involved in its formation provides insights into congenital malformations affecting its function and therefore the survival of the organism. Because many developmental mechanisms are highly conserved, it is possible to extrapolate from observations made in invertebrate and vertebrate model organisms to humans. This review will highlight the contributions made through studying heart development in avian embryos, particularly the chicken. The major advantage of chick embryos is their accessibility for surgical manipulation and functional interference approaches, both gain- and loss-of-function. In addition to experiments performed in ovo, the dissection of tissues for ex vivo culture, genomic, or biochemical approaches is straightforward. Furthermore, embryos can be cultured for time-lapse imaging, which enables tracking of fluorescently labeled cells and detailed analysis of tissue morphogenesis. Owing to these features, investigations in chick embryos have led to important discoveries, often complementing genetic studies in mice and zebrafish. As well as including some historical aspects, we cover here some of the crucial advances made in understanding early heart development using the chicken model.
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Affiliation(s)
- Johannes G Wittig
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK.
| | - Andrea Münsterberg
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK.
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11
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Costain G, Lionel AC, Ogura L, Marshall CR, Scherer SW, Silversides CK, Bassett AS. Genome-wide rare copy number variations contribute to genetic risk for transposition of the great arteries. Int J Cardiol 2015; 204:115-21. [PMID: 26655555 DOI: 10.1016/j.ijcard.2015.11.127] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 11/10/2015] [Accepted: 11/20/2015] [Indexed: 12/16/2022]
Abstract
BACKGROUND Transposition of the great arteries (TGA) is an uncommon but severe congenital heart malformation of unknown etiology. Rare copy number variations (CNVs) have been implicated in other, more common conotruncal heart defects like tetralogy of Fallot (TOF), but there are as yet no CNV studies dedicated to TGA. METHODS Using high-resolution genome-wide microarrays and rigorous methods, we investigated CNVs in a group of prospectively recruited adults with TGA (n=101) from a single center. We compared rare CNV burden to well-matched cohorts of controls and TOF cases, adjudicating rarity using 10,113 independent population-based controls and excluding all subjects with 22q11.2 deletions. We identified candidate genes for TGA based on rare CNVs that overlapped the same gene in unrelated individuals, and pre-existing evidence suggesting a role in cardiac development. RESULTS The TGA group was significantly enriched for large rare CNVs (2.3-fold increase, p=0.04) relative to controls, to a degree comparable with the TOF group. Extra-cardiac features were not reliable predictors of rare CNV burden. Smaller rare CNVs helped to narrow critical regions for conotruncal defects at chromosomes 10q26 and 13q13. Established and novel candidate susceptibility genes identified included ACKR3, IFT57, ITGB8, KL, NF1, NKX1-2, RERE, SLC8A1, SOX18, and ULK1. CONCLUSIONS These data demonstrate a genome-wide role for rare CNVs in genetic risk for TGA. The findings provide further support for a genetically-related spectrum of congenital heart disease that includes TGA and TOF.
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Affiliation(s)
- Gregory Costain
- Clinical Genetics Research Program, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; Medical Genetics Residency Training Program, University of Toronto, and Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Anath C Lionel
- The Centre for Applied Genomics and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada; McLaughlin Centre and Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Lucas Ogura
- Clinical Genetics Research Program, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Christian R Marshall
- The Centre for Applied Genomics and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Stephen W Scherer
- The Centre for Applied Genomics and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada; McLaughlin Centre and Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Candice K Silversides
- The Toronto Congenital Cardiac Centre for Adults & Division of Cardiology in the Department of Medicine, University Health Network, Toronto, Ontario, Canada.
| | - Anne S Bassett
- Clinical Genetics Research Program, Centre for Addiction and Mental Health, Toronto, Ontario, Canada; The Toronto Congenital Cardiac Centre for Adults & Division of Cardiology in the Department of Medicine, University Health Network, Toronto, Ontario, Canada; Department of Psychiatry, Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada; The Dalglish Family Hearts and Minds Clinic for 22q11.2 Deletion Syndrome, University Health Network, Toronto, Ontario, Canada; Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.
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12
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Affiliation(s)
- Anping Cai
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China (A.C., Y.Z., L.L.)
| | - Yingling Zhou
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China (A.C., Y.Z., L.L.)
| | - Liwen Li
- Department of Cardiology, Guangdong Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China (A.C., Y.Z., L.L.)
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13
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Loirand G, Sauzeau V, Pacaud P. Small G Proteins in the Cardiovascular System: Physiological and Pathological Aspects. Physiol Rev 2013; 93:1659-720. [DOI: 10.1152/physrev.00021.2012] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Small G proteins exist in eukaryotes from yeast to human and constitute the Ras superfamily comprising more than 100 members. This superfamily is structurally classified into five families: the Ras, Rho, Rab, Arf, and Ran families that control a wide variety of cell and biological functions through highly coordinated regulation processes. Increasing evidence has accumulated to identify small G proteins and their regulators as key players of the cardiovascular physiology that control a large panel of cardiac (heart rhythm, contraction, hypertrophy) and vascular functions (angiogenesis, vascular permeability, vasoconstriction). Indeed, basal Ras protein activity is required for homeostatic functions in physiological conditions, but sustained overactivation of Ras proteins or spatiotemporal dysregulation of Ras signaling pathways has pathological consequences in the cardiovascular system. The primary object of this review is to provide a comprehensive overview of the current progress in our understanding of the role of small G proteins and their regulators in cardiovascular physiology and pathologies.
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Affiliation(s)
- Gervaise Loirand
- INSERM, UMR S1087; University of Nantes; and CHU Nantes, l'Institut du Thorax, Nantes, France
| | - Vincent Sauzeau
- INSERM, UMR S1087; University of Nantes; and CHU Nantes, l'Institut du Thorax, Nantes, France
| | - Pierre Pacaud
- INSERM, UMR S1087; University of Nantes; and CHU Nantes, l'Institut du Thorax, Nantes, France
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14
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Buttler K, Becker J, Pukrop T, Wilting J. Maldevelopment of dermal lymphatics in Wnt5a-knockout-mice. Dev Biol 2013; 381:365-76. [DOI: 10.1016/j.ydbio.2013.06.028] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 06/12/2013] [Accepted: 06/28/2013] [Indexed: 01/22/2023]
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15
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RhoA regulation of cardiomyocyte differentiation. ScientificWorldJournal 2013; 2013:491546. [PMID: 23935420 PMCID: PMC3712199 DOI: 10.1155/2013/491546] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 05/14/2013] [Indexed: 12/03/2022] Open
Abstract
Earlier findings from our laboratory implicated RhoA in heart developmental processes. To investigate factors that potentially regulate RhoA expression, RhoA gene organisation and promoter activity were analysed. Comparative analysis indicated strict conservation of both gene organisation and coding sequence of the chick, mouse, and human RhoA genes. Bioinformatics analysis of the derived promoter region of mouse RhoA identified putative consensus sequence binding sites for several transcription factors involved in heart formation and organogenesis generally. Using luciferase reporter assays, RhoA promoter activity was shown to increase in mouse-derived P19CL6 cells that were induced to differentiate into cardiomyocytes. Overexpression of a dominant negative mutant of mouse RhoA (mRhoAN19) blocked this cardiomyocyte differentiation of P19CL6 cells and led to the accumulation of the cardiac transcription factors SRF and GATA4 and the early cardiac marker cardiac α-actin. Taken together, these findings indicate a fundamental role for RhoA in the differentiation of cardiomyocytes.
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Iskratsch T, Reijntjes S, Dwyer J, Toselli P, Dégano IR, Dominguez I, Ehler E. Two distinct phosphorylation events govern the function of muscle FHOD3. Cell Mol Life Sci 2012; 70:893-908. [PMID: 23052206 DOI: 10.1007/s00018-012-1154-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Revised: 08/17/2012] [Accepted: 08/30/2012] [Indexed: 01/26/2023]
Abstract
Posttranslational modifications such as phosphorylation are universally acknowledged regulators of protein function. Recently we characterised a striated muscle-specific isoform of the formin FHOD3 that displays distinct subcellular targeting and protein half-life compared to its non-muscle counterpart and which is dependent on phosphorylation by CK2 (formerly casein kinase 2). We now show that the two isoforms of FHOD3 are already expressed in the vertebrate embryonic heart. Analysis of CK2 alpha knockout mice showed that phosphorylation by CK2 is also required for proper targeting of muscle FHOD3 to the myofibrils in embryonic cardiomyocytes in situ. The localisation of muscle FHOD3 in the sarcomere varies depending on the maturation state, being either broader or restricted to the Z-disc proper in the adult heart. Following myofibril disassembly, such as that in dedifferentiating adult rat cardiomyocytes in culture, the expression of non-muscle FHOD3 is up-regulated, which is reversed once the myofibrils are reassembled. The shift in expression levels of different isoforms is accompanied by an increased co-localisation with p62, which is involved in autophagy, and affects the half-life of FHOD3. Phosphorylation of three amino acids in the C-terminus of FHOD3 by ROCK1 is sufficient for activation, which results in increased actin filament synthesis in cardiomyocytes and also a broader localisation pattern of FHOD3 in the myofibrils. ROCK1 can directly phosphorylate FHOD3, and FHOD3 seems to be the downstream mediator of the exaggerated actin filament formation phenotype that is induced in cardiomyocytes upon the overexpression of constitutively active ROCK1. We conclude that the expression of the muscle FHOD3 isoform is characteristic of the healthy mature heart and that two distinct phosphorylation events are crucial to regulate the activity of this isoform in thin filament assembly and maintenance.
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Affiliation(s)
- Thomas Iskratsch
- Muscle Cell Biology Section, The Randall Division of Cell and Molecular Biophysics and The Cardiovascular Division, BHF Research Excellence Centre, King's College London, New Hunt's House, Guy's Campus, London, SE1 1UL, UK
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17
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Vicente-Steijn R, Kolditz DP, Mahtab EAF, Askar SFA, Bax NAM, VAN DER Graaf LM, Wisse LJ, Passier R, Pijnappels DA, Schalij MJ, Poelmann RE, Gittenberger-DE Groot AC, Jongbloed MRM. Electrical activation of sinus venosus myocardium and expression patterns of RhoA and Isl-1 in the chick embryo. J Cardiovasc Electrophysiol 2011; 21:1284-92. [PMID: 20455990 DOI: 10.1111/j.1540-8167.2010.01790.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
UNLABELLED Electrical Activity and RhoA in the Embryo. INTRODUCTION Myocardium at the venous pole (sinus venosus) of the heart has gained clinical interest as arrhythmias can be initiated from this area. During development, sinus venosus myocardium is incorporated to the primary heart tube and expresses different markers than primary myocardium. We aimed to elucidate the development of sinus venosus myocardium, including the sinoatrial node (SAN), by studying expression patterns of RhoA in relation to other markers, and by studying electrical activation patterns of the developing sinus venosus myocardium. METHODS AND RESULTS Expression of RhoA, myocardial markers cTnI and Nkx2.5, transcription factors Isl-1 and Tbx18, and cation channel HCN4 were examined in sequential stages in chick embryos. Electrical activation patterns were studied using microelectrodes and optical mapping. Embryonic sinus venosus myocardium is cTnI and HCN4 positive, Nkx2.5 negative, complemented by distinct patterns of Isl-1 and Tbx18. During development, initial myocardium-wide expression of RhoA becomes restricted to right-sided sinus venosus myocardium, comprising the SAN. Electrophysiological measurements revealed initial capacity of both atria to show electrical activity that in time shifts to a right-sided dominance, coinciding with persistence of RhoA, Tbx18, and HCN4 and absence of Nkx2.5 expression in the definitive SAN. CONCLUSION Results show an initially bilateral electrical potential of sinus venosus myocardium evolving into a right-sided activation pattern during development, and suggest a role for RhoA in conduction system development. We hypothesize an initial sinus venosus-wide capacity to generate pacemaker signals, becoming confined to the definitive SAN. Lack of differentiation toward a chamber phenotype would explain ectopic pacemaker foci.
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Affiliation(s)
- Rebecca Vicente-Steijn
- Department of Anatomy and Embryology Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands
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18
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Pan H, Bachelder RE. Autocrine Semaphorin3A stimulates eukaryotic initiation factor 4E-dependent RhoA translation in breast tumor cells. Exp Cell Res 2010; 316:2825-32. [PMID: 20655307 DOI: 10.1016/j.yexcr.2010.07.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Revised: 07/15/2010] [Accepted: 07/15/2010] [Indexed: 11/19/2022]
Abstract
Translation of the small G protein RhoA in neurons is regulated by the eukaryotic translation initiation factor eIF4E. Here we show that this translation factor also regulates RhoA expression and activity in breast cancer cells. The introduction of eIF4E into breast tumor cells increased RhoA protein levels, while expression of an eIF4E siRNA reduced RhoA expression. Previous studies indicate that the axon repulsion factor Semaphorin3A (Sema3A) stimulates the eIF4E-dependent translation of RhoA in neurons, and breast tumor cells support autocrine Sema3A signaling. Accordingly, we next examined if autocrine Sema3A signaling drives eIF4E-dependent RhoA translation in breast cancer cells. The incubation of breast tumor cells with recombinant Sema3A rapidly increased eIF4E activity, RhoA protein levels, and RhoA activity. This Sema3A activity was blocked in tumor cells expressing an shRNA-specific for the Sema3A receptor, Neuropilin-1 (NP-1), as well as in cells incubated with an eIF4E inhibitor. Importantly, RhoA protein levels were reduced in Sema3A shRNA-expressing compared to control shRNA-expressing breast tumor cells, demonstrating that autocrine Sema3A increases RhoA expression in breast cancer. Considering that Sema3A suppresses axon extension by stimulating RhoA translation, we next examined if the Sema3A/RhoA axis impacts breast tumor cell migration. The incubation of control breast tumor cells, but not RhoA shRNA-expressing cells, with rSema3A significantly reduced their migration. Collectively, these studies indicate that Sema3A impedes breast tumor cell migration in part by stimulating RhoA. These findings identify common signaling pathways that regulate the navigation of neurons and breast cancer cells, thus suggesting novel targets for suppressing breast tumor cell migration.
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Affiliation(s)
- Hongjie Pan
- Department of Pathology, Duke University Medical Center, D.U.M.C, Durham, NC 27715, USA
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19
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Münsterberg A, Yue Q. Cardiac progenitor migration and specification: The dual function of Wnts. Cell Adh Migr 2008; 2:74-6. [PMID: 19262099 DOI: 10.4161/cam.2.2.6295] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The heart is the first organ to function during vertebrate development and cardiac progenitors, are among the first cell lineages to be established from mesoderm cells emerging from the primitive streak during gastrulation. Cardiac progenitors have been mapped in the epiblast of pre-streak embryos. In the early chick gastrula they are located in the mid-primitive streak, from which they enter the mesoderm bilaterally. However, migration routes of cardiac progenitors have never been directly observed within the embryo and the factor(s) controlling their movement are not known. Furthermore, it is not understood how signals controlling cell movement are integrated with those that determine cell fate. Long-term video microscopy combined with GFP labelling and image processing enabled us to observe the movement patterns of prospective cardiac cells in whole embryos in real time. Embryo manipulations and the analysis of explants suggest that Wnt3a plays a crucial role in guiding these cells through a RhoA dependent mechanism involving negative chemotaxis. Wnt3a is expressed at high levels in the amniote primitive streak and ectopic signalling activity caused wider movement trajectories resulting in cardia bifida, which was rescued by dominant-negative Wnt3a. Our studies revealed Wnt3a-RhoA mediated chemo-repulsion as a novel mechanism guiding cardiac progenitors. This activity can act at long-range and does not interfere with cardiac cell fate specification.
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Affiliation(s)
- Andrea Münsterberg
- Cell and Developmental Biology, School of Biological Sciences, University of East Anglia, Norwich, Norfolk, United Kingdom.
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20
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Townsend TA, Wrana JL, Davis GE, Barnett JV. Transforming growth factor-beta-stimulated endocardial cell transformation is dependent on Par6c regulation of RhoA. J Biol Chem 2008; 283:13834-41. [PMID: 18343818 DOI: 10.1074/jbc.m710607200] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Valvular heart disease due to congenital abnormalities or pathology is a major cause of mortality and morbidity. Understanding the cellular processes and molecules that regulate valve formation and remodeling is required to develop effective therapies. In the developing heart, epithelial-mesenchymal transformation (EMT) in a subpopulation of endocardial cells in the atrioventricular cushion (AVC) is an important step in valve formation. Transforming growth factor-beta (TGFbeta) has been shown to be an important regulator of AVC endocardial cell EMT in vitro and mesenchymal cell differentiation in vivo. Recently Par6c (Par6) has been shown to function downstream of TGFbeta to recruit Smurf1, an E3 ubiquitin ligase, which targets RhoA for degradation to control apical-basal polarity and tight junction dissolution. We tested the hypothesis that Par6 functions in a pathway that regulates endocardial cell EMT. Here we show that the Type I TGFbeta receptor ALK5 is required for endocardial cell EMT. Overexpression of dominant negative Par6 inhibits EMT in AVC endocardial cells, whereas overexpression of wild-type Par6 in normally non-transforming ventricular endocardial cells results in EMT. Overexpression of Smurf1 in ventricular endocardial cells induces EMT. Decreasing RhoA activity using dominant negative RhoA or small interfering RNA in ventricular endocardial cells also increases EMT, whereas overexpression of constitutively active RhoA in AVC endothelial cells blocks EMT. Manipulation of Rac1 or Cdc42 activity is without effect. These data demonstrate a functional role for Par6/Smurf1/RhoA in regulating EMT in endocardial cells.
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Affiliation(s)
- Todd A Townsend
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee 37232-6600, USA
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21
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Yue Q, Wagstaff L, Yang X, Weijer C, Münsterberg A. Wnt3a-mediated chemorepulsion controls movement patterns of cardiac progenitors and requires RhoA function. Development 2008; 135:1029-37. [PMID: 18256196 DOI: 10.1242/dev.015321] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The heart is the first organ to function during vertebrate development and cardiac progenitors are among the first cell lineages to be established. In the chick, cardiac progenitors have been mapped in the epiblast of pre-streak embryos, and in the early gastrula they are located in the mid-primitive streak, from which they enter the mesoderm bilaterally. Signals controlling the specification of cardiac cells have been well documented; however, migration routes of cardiac progenitors have not been directly observed within the embryo and the factor(s) controlling their movement are not known. In addition, it is not clear how cell movement is coordinated with cell specification in the early embryo. Here we use live imaging to show that cardiac progenitors migrate in highly directed trajectories, which can be controlled by Wnt3a. Ectopic Wnt3a altered movement trajectories and caused cardia bifida. This was rescued by electroporation of dominant-negative DN-Wnt3a into prospective cardiac cells. Explant essays and mutant analysis showed that cellular guidance involved repulsion in response to Wnt3a and required RhoA function. It has been shown that Wnt3a inhibits cardiogenic cell specification through a beta-catenin-dependent pathway. On the basis of our results, we propose that Wnt3a concomitantly guides the movement of cardiac progenitors by a novel mechanism involving RhoA-dependent chemorepulsion.
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Affiliation(s)
- Qiaoyun Yue
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK
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22
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Early incorporation of obscurin into nascent sarcomeres: implication for myofibril assembly during cardiac myogenesis. Histochem Cell Biol 2008; 129:463-78. [PMID: 18219491 DOI: 10.1007/s00418-008-0378-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/03/2008] [Indexed: 10/22/2022]
Abstract
Obscurin is a recently identified giant multidomain muscle protein whose functions remain poorly understood. The goal of this study was to investigate the process of assembly of obscurin into nascent sarcomeres during the transition from non-striated myofibril precursors to striated structure of differentiating myofibrils in cell cultures of neonatal rat cardiac myocytes. Double immunofluorescent labeling and high resolution confocal microscopy demonstrated intense incorporation of obscurin in the areas of transition from non-striated to striated regions on the tips of developing myofibrils and at the sites of lateral fusion of nascent sarcomere bundles. We found that obscurin rapidly and precisely accumulated in the middle of the A-band regions of the terminal newly assembled half-sarcomeres in the zones of transition from the continuous, non-striated pattern of sarcomeric alpha-actinin distribution to cross-striated structure of laterally expanding nascent Z-discs. The striated pattern of obscurin typically ended at these points. This occurred before the assembly of morphologically differentiated terminal Z-discs of the assembling sarcomeres on the tips of growing myofibrils. The presence of obscurin in the areas of the terminal Z-discs of each new sarcomere was detected at the same time or shortly after complete assembly of sarcomeric structure. Many non-striated fibers with very low concentration of obscurin were already immunopositive for sarcomeric actin and myosin. This suggests that obscurin may serve for organization and alignment of myofilaments into the striated pattern. The comparison of obscurin and titin localization in these areas showed that obscurin assembly into the A-bands occurred soon after or concomitantly with incorporation of titin. Electron microscopy of growing myofibrils demonstrated intense formation and integration of myosin filaments into the "open" half-assembled sarcomeres in the areas of the terminal Z-I structures and at the lateral surfaces of newly formed, terminally located nascent sarcomeres. This process progressed before the assembly of the second-formed, terminal Z-discs of new sarcomeres and before the development of ultrastructurally detectable mature M-lines that define the completion of myofibril assembly, which supports the data of immunocytochemical study. Abundant non-aligned sarcomeres in immature myofibrils located on the growing tips were spatially separated and underwent the transition to the registered, aligned pattern. The sarcoplasmic reticulum, the organelle known to interact with obscurin, assembled around each new sarcomere. These results suggest that obscurin is directly involved in the proper positioning and alignment of myofilaments within nascent sarcomeres and in the establishment of the registered pattern of newly assembled myofibrils and the sarcoplasmic reticulum at advanced stages of myofibrillogenesis.
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Abstract
In this review we discuss the major morphogenetic and regulative events that control myocardial progenitor cells from the time that they delaminate from the epiblast in the primitive streak to their differentiation into cardiomyocytes in the heart tube. During chick and mouse embryogenesis, myocardial progenitor cells go through four specific processes that are sequential but overlapping: specification of the cardiogenic mesoderm, determination of the bilaterally symmetric heart fields, patterning of the heart field, and finally cardiomyocyte differentiation and formation of the heart tube. We describe the morphological and molecular events that play a pivotal role in each of these four processes.
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Affiliation(s)
- Radwan Abu-Issa
- Department of Pediatrics, Neonatal-Perinatal Research Institute, Duke University, Durham, NC 27712, USA.
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24
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Tavares ALP, Mercado-Pimentel ME, Runyan RB, Kitten GT. TGF beta-mediated RhoA expression is necessary for epithelial-mesenchymal transition in the embryonic chick heart. Dev Dyn 2007; 235:1589-98. [PMID: 16598712 DOI: 10.1002/dvdy.20771] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Endothelia in the atrioventricular canal (AVC) of the embryonic heart undergo an epithelial-mesenchymal transition (EMT) and migrate into the underlying extracellular matrix. We explore here whether RhoA mediates this EMT. RhoA was detected in all cells of the chick heart during the stages studied. Expression was elevated when EMT was actively occurring. Explants treated with C3 exoenzyme in collagen gel cultures showed a significant decrease in mesenchymal cell numbers. siRNA was used to inhibit RhoA mRNA, and both activated endothelial and mesenchymal cells decreased significantly with treatment. Loss of RhoA produced a reduction of RhoB, cyclin-b2, and beta-catenin messages showing that these genes are regulated downstream of RhoA. In contrast, runx-2 was not reduced. Inhibition of TGFbeta3 or TGFbeta2 activity caused a large reduction of RhoA message. These data place RhoA in TGFbeta regulated pathways for both endothelial activation and mesenchymal invasion and demonstrate a functional requirement during EMT.
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Affiliation(s)
- André Luiz P Tavares
- Department of Morphology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
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25
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Henderson DJ, Phillips HM, Chaudhry B. Vang-like 2 and noncanonical Wnt signaling in outflow tract development. Trends Cardiovasc Med 2007; 16:38-45. [PMID: 16473760 DOI: 10.1016/j.tcm.2005.11.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2005] [Revised: 11/07/2005] [Accepted: 11/10/2005] [Indexed: 10/25/2022]
Abstract
Despite rapid advances in cardiovascular developmental genetics, the precise morphogenetic processes that coordinate heart development, and the genes and signaling pathways that regulate them remain unclear. In this review, we describe a highly conserved signaling pathway, the noncanonical Wnt (planar cell polarity) pathway, and its relationship to cardiovascular development and congenital heart defects. This pathway regulates cell polarity and polarized cell movements in a variety of contexts. Mutations in several genes in this pathway and specifically in the Vang-like 2 (Vangl2) (strabismus) gene, result in abnormalities in the remodeling of the outflow tract and, ultimately, in the cardiac alignment defect double-outlet right ventricle. Polarized cell migration of cardiomyocytes into the outflow tract cushions is inhibited when Vangl2 function is disturbed, suggesting that the noncanonical Wnt pathway may regulate this aspect of outflow tract remodeling. These studies suggest that mutations in Vangl2 and other components of the noncanonical Wnt pathway, may be candidates for causing congenital outflow tract defects in humans.
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Affiliation(s)
- Deborah J Henderson
- Institute of Human Genetics, University of Newcastle upon Tyne, International Centre for Life, Newcastle upon Tyne NE1 3BZ, UK.
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26
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Gonçalves S, Cairney J, Rodríguez MP, Cánovas F, Oliveira M, Miguel C. PpRab1, a Rab GTPase from maritime pine is differentially expressed during embryogenesis. Mol Genet Genomics 2007; 278:273-82. [PMID: 17562081 DOI: 10.1007/s00438-007-0247-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2006] [Accepted: 05/07/2007] [Indexed: 10/23/2022]
Abstract
Rab-related small GTP-binding proteins are known to be involved in the regulation of the vesicular transport system in eukaryotic cells. We report the characterization of a previously isolated full-length cDNA PpRab1 from Pinus pinaster. Amino acid sequence analysis revealed the presence of G1-G5 conserved domains of the GTPase Ras superfamily and a double cysteine motif in the C-terminal, characteristic of Rab proteins. The PpRab1 protein shows high sequence similarity to several Rab1 GTP-binding proteins in plants. Phylogenetic analysis showed that, within the Ras superfamily, PpRab1 is more closely related to the Rab family and within this, PpRab1 protein was found to cluster with Arabidopsis subfamily AtRABE, whose members are known to regulate ER-to-Golgi membrane trafficking steps. PpRab1 transcripts were expressed at constitutively high levels for the initial stages of zygotic embryo development, and then their relative abundance decreased as embryo matures. The PpRab1 transcript is not embryo-specific as it was found in roots, cotyledons and hypocotyls. An increase in PpRab1 expression level was observed when seeds are germinated and collected at successive time points of development. In situ RT-PCR analysis revealed an expression signal in early zygotic embryos. In view of the proposed roles of Rab1 GTP-binding protein, the possible function of the protein encoded by PpRab1 in embryogenesis is discussed.
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Affiliation(s)
- Sónia Gonçalves
- Forest Biotech Lab, Instituto de Biologia Experimental e Tecnológica (IBET)/Instituto de Tecnologia Química e Biológica (ITQB), Quinta do Marquês, 2784-505 Oeiras, Portugal
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27
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D'Amico L, Scott IC, Jungblut B, Stainier DYR. A mutation in zebrafish hmgcr1b reveals a role for isoprenoids in vertebrate heart-tube formation. Curr Biol 2007; 17:252-9. [PMID: 17276918 DOI: 10.1016/j.cub.2006.12.023] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2006] [Revised: 11/01/2006] [Accepted: 11/22/2006] [Indexed: 10/23/2022]
Abstract
In vertebrates, the morphogenetic assembly of the primitive heart tube requires the medial migration and midline fusion of the bilateral myocardial epithelia. Several mutations that result in abnormal heart-tube formation have been studied; however, an understanding of the underlying molecular and cellular mechanisms of the migration and fusion of these epithelial sheets is far from complete. In a forward genetic screen to identify genes regulating early zebrafish heart development, we identified a mutation in the 3-hydroxy-3-methylglutaryl-Coenzyme A reductase 1b (hmgcr1b) gene that affects myocardial migration to the midline and subsequent heart-tube morphogenesis. The mutant phenotype can be rescued with injections of mevalonate, the direct product of HMGCR activity. Furthermore, treatment of embryos with pharmacological inhibitors of isoprenoid synthesis, which occurs downstream of mevalonate production, resulted in defective heart-tube formation. Interestingly, in hmgcr1b mutant embryos and embryos treated with HMGCR inhibitors, both RasCT20-eGFP and RhoaCT32-eGFP fusion proteins were mislocalized away from the plasma membrane in embryonic myocardial cells. We conclude that protein prenylation, acting downstream of Hmgcr1b and possibly through Ras and, or, Rho signaling, is required for the morphogenesis of the myocardial sheets for formation of the primitive heart tube.
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Affiliation(s)
- Leonard D'Amico
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, University of California, San Francisco, 1550 Fourth Street, San Francisco, California 94158, USA
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28
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Gieni RS, Hendzel MJ. Mechanotransduction from the ECM to the genome: Are the pieces now in place? J Cell Biochem 2007; 104:1964-87. [PMID: 17546585 DOI: 10.1002/jcb.21364] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A multitude of biochemical signaling processes have been characterized that affect gene expression and cellular activity. However, living cells often need to integrate biochemical signals with mechanical information from their microenvironment as they respond. In fact, the signals received by shape alone can dictate cell fate. This mechanotrasduction of information is powerful, eliciting proliferation, differentiation, or apoptosis in a manner dependent upon the extent of physical deformation. The cells internal "prestressed" structure and its "hardwired" interaction with the extra-cellular matrix (ECM) appear to confer this ability to filter biochemical signals and decide between divergent cell functions influenced by the nature of signals from the mechanical environment. In some instances mechanical signaling through the tissue microenvironment has been shown to be dominant over genomic defects, imparting a normal phenotype on cells that otherwise have transforming genetic lesions. This mechanical control of phenotype is postulated to have a central role in embryogenesis, tissue physiology as well as the pathology of a wide variety of diseases, including cancer. We will briefly review studies showing physical continuity between the external cellular microenvironment and the interior of the cell nucleus. Newly characterized structures, termed nuclear envelope lamina spanning complexes (NELSC), and their interactions will be described as part of a model for mechanical transduction of extracellular cues from the ECM to the genome.
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Affiliation(s)
- Randall S Gieni
- Cross Cancer Institute and Department of Oncology, Faculty of Medicine, University of Alberta, Edmonton, Alberta, Canada
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29
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Sakata H, Sakabe M, Matsui H, Kawada N, Nakatani K, Ikeda K, Yamagishi T, Nakajima Y. Rho kinase inhibitor Y27632 affects initial heart myofibrillogenesis in cultured chick blastoderm. Dev Dyn 2007; 236:461-72. [PMID: 17195179 DOI: 10.1002/dvdy.21055] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
During early vertebrate development, Rho-associated kinases (ROCKs) are involved in various developmental processes. Here, we investigated spatiotemporal expression patterns of ROCK1 protein and examined the role of ROCK during initial heart myofibrillogenesis in cultured chick blastoderm. Immunohistochemistry showed that ROCK1 protein was distributed in migrating mesendoderm cells, visceral mesoderm of the pericardial coelom (from which cardiomyocytes will later develop), and cardiomyocytes of the primitive heart tube. Pharmacological inhibition of ROCK by Y27632 did not alter the myocardial specification process in cultured posterior blastoderm. However, Y27632 disturbed the formation of striated heart myofibrils in cultured posterior blastoderm. Furthermore, Y27632 affected the formation of costamere, a vinculin/integrin-based rib-like cell adhesion site. In such cardiomyocytes, cell-cell adhesion was disrupted and N-cadherin was distributed in the perinuclear region. Pharmacological inactivation of myosin light chain kinase, a downstream of ROCK, by ML-9 perturbed the formation of striated myofibrils as well as costameres, but not cell-cell adhesion. These results suggest that ROCK plays a role in the formation of initial heart myofibrillogenesis by means of actin-myosin assembly, and focal adhesion/costamere and cell-cell adhesion.
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Affiliation(s)
- Hirokazu Sakata
- Department of Anatomy and Cell Biology, Graduate School of Medicine, Osaka City University, Asahimachi, Osaka, Japan
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30
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Huang YS, Wang SM, Hsu KL, Tseng YZ, Wu JC. Mechanism of oleic acid-induced myofibril disassembly in rat cardiomyocytes. J Cell Biochem 2007; 102:638-49. [PMID: 17428005 DOI: 10.1002/jcb.21317] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
This study investigated the mechanism of oleic acid (OA)-induced disassembly of myofibrils in cardiomyocytes. OA treatment disrupted myofibrils, as revealed by the disorganization of several sarcomeric proteins. Since focal adhesions (FAs) are implicated in myofibril assembly, we examined structural changes in FAs after OA treatment. Immunofluorescence studies with antibodies against FA proteins (vinculin, integrin beta1D, and paxillin) showed that FAs and costameres disintegrated or disappeared after OA treatment and that the changes in FA proteins occurred prior to myofibril disassembly. The effects of OA on FAs and myofibrils were reversed after removal of OA. OA decreased expression of integrin beta1D, paxillin, vinculin, and actin, and induced tyrosine dephosphorylation of FA kinase (FAK) and paxillin. These effects were blocked by pretreatment with sodium orthovanadate, a protein tyrosine phosphatase (PTP) inhibitor. This inhibitor also prevented OA-induced myofibril disassembly, indicating the involvement of PTP in myofibril disassembly. Furthermore, OA increased protein levels of PTP-PEST. The upregulation of this phosphatase correlated with the tyrosine dephosphorylation of paxillin and FAK, which are targets for PTP-PEST. In addition, OA decreased RhoA activity and the phosphorylation of cofilin, a downstream target of RhoA. Cofilin dephosphorylation increased its actin-severing activity and led to the depolymerization of F-actin, which might provide another potential mechanism for OA-induced myofibril disassembly.
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Affiliation(s)
- Yuahn-Sieh Huang
- Department of Anatomy and Cell Biology, College of Medicine, National Taiwan University, Taipei 10051, Taiwan
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31
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Zhu S, Liu L, Korzh V, Gong Z, Low BC. RhoA acts downstream of Wnt5 and Wnt11 to regulate convergence and extension movements by involving effectors Rho Kinase and Diaphanous: Use of zebrafish as an in vivo model for GTPase signaling. Cell Signal 2006; 18:359-72. [PMID: 16019189 DOI: 10.1016/j.cellsig.2005.05.019] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2005] [Accepted: 05/06/2005] [Indexed: 01/09/2023]
Abstract
Gastrulation shapes the early embryos by forming three germ layers, ectoderm, mesoderm and endoderm. In vertebrates, this process requires massive cell rearrangement including convergence and extension (CE) movements that involve narrowing and lengthening of embryonic tissues as well as cell elongation. Such polarization and movements require precise reorganization and regulation of the cytoskeleton network and cell adhesion. Rho small GTPases are key regulators for dynamic actin cytoskeleton. However, the signaling mechanisms underlying their functions in CE remain to be further elucidated. We have cloned the zebrafish Danio rerio rhoA and by capitalizing on the specific functional knockdown using morpholinos against rhoA and the availability of CE mutants defective in Wnt signaling, we showed that rhoA morphants were reminiscent to noncanonical wnt mutants with serious disruption in CE movements. Injection of rhoA mRNA effectively rescued such defects in wnt5 and wnt11 mutants. Furthermore, CE defects in rhoA knockdown or wnt mutants can be suppressed through functional bypass after ectopic expression of the two mammalian Rho effectors, the Rho kinase and Diaphanous (mDia). These results provide the first evidence that the RhoA in vivo acts downstream of Wnt5 and Wnt11 to effect, without affecting cell fates, on the CE movements in zebrafish embryos. Significantly, it elicits such effect via both effectors, Rho kinase and Dia. These findings also support the versatility of the zebrafish as a model to further investigate the roles of various classes of small GTPases in regulating cell dynamics in vivo.
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Affiliation(s)
- Shizhen Zhu
- Cell Signaling and Developmental Biology Laboratory, National University of Singapore, 14 Science Drive 4, Singapore 117543, The Republic of Singapore
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Iwakiri R, Kobayashi K, Okinami S, Kobayashi H. Suppression of Mitf by small interfering RNA induces dedifferentiation of chick embryonic retinal pigment epithelium. Exp Eye Res 2005; 81:15-21. [PMID: 15978250 DOI: 10.1016/j.exer.2005.01.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2004] [Revised: 01/03/2005] [Accepted: 01/04/2005] [Indexed: 11/17/2022]
Abstract
Recent studies indicate a key role of Mitf (microphthalmia-associated transcription factor) in the differentiation of the retinal pigment epithelium (RPE). To explore transdifferentiation processes, we used small interfering RNA (siRNA) targeting Mitf. Transfection of embryonic chick RPE cells with a non-silencing fluorescein-labelled control siRNA demonstrated a high (84%) transfection efficiency. Transfection of Mitf siRNA reduced Mitf synthesis at the mRNA and protein levels as analysed by real-time RT-PCR and Western blot. Mitf siRNA suppressed the expression of Mitf RNA to 25.0% of the level in control cells (P<0.005). The expression of melanosomal matrix glycoprotein 115 (MMP115), a marker of differentiated pigment cells, was also markedly suppressed (to 52.2+/-6.6%) (P<0.0005). Moreover, the expression of Pax6 was increased by Mitf siRNA (to 143.5+/-18.0%) (P<0.0005), and induced dedifferentiation of the RPE cells. These data suggest siRNA can be an effective gene silencing approach in RPE, and reduction of Mitf expression is essential for the dedifferentiation of RPE cells.
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Affiliation(s)
- Ryo Iwakiri
- Department of Ophthalmology, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga 849-8501, Japan
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Abstract
RhoA and Rho-kinase (ROCK) participate in a wide variety of cell signal functions such as cell growth, smooth and cardiac muscle contraction, cytoskeleton rearrangement, cell migration and proliferation. In vascular smooth muscle cells, RhoA and ROCK play an important role in Ca2+ sensitization and regulate vascular smooth muscle tone. In the heart, RhoA and ROCK mediate hypertrophic response leading to cardiac hypertrophy. Recent cellular and molecular biology studies using ROCK inhibitors such as Y-27632 and fasudil have indicated a pivotal role of the RhoA-ROCK cascade in many aspects of cardiovascular function such as cardiac hypertrophy and ventricular remodeling following myocardial infarction. Inhibition of the RhoA-ROCK signaling pathway may be a suitable target for a number of cardiovascular diseases including hypertension, atherosclerosis, diabetes and hypertrophic heart failure. This review focuses on the current understanding of the RhoA-ROCK signal pathway in heart diseases and discusses the use of ROCK inhibitors as therapeutic agents for heart diseases ranging from hypertensive cardiomyopathy to heart failure.
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Affiliation(s)
- Jun Ren
- Center for Cardiovascular Research and Alternative Medicine and Division of Pharmaceutical Sciences, University of Wyoming, Laramie, WY 82071, USA.
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Phillips HM, Murdoch JN, Chaudhry B, Copp AJ, Henderson DJ. Vangl2 acts via RhoA signaling to regulate polarized cell movements during development of the proximal outflow tract. Circ Res 2005; 96:292-9. [PMID: 15637299 DOI: 10.1161/01.res.0000154912.08695.88] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Loop-tail (Lp) mice develop double outlet right ventricle and aortic arch defects, and the defects are caused by mutations in the Vangl2 gene. Vangl2 mRNA is found in the outflow tract myocardium, including the myocardializing cells that migrate into the outflow tract cushions. Analysis of muscularization of the outflow tract septum showed that this process is compromised in Lp/Lp fetuses. Vangl2 is a component of the noncanonical Wnt, planar cell polarity (PCP) pathway that signals via RhoA. We therefore looked for evidence of polarization in myocardializing cells. In wild-type fetuses, myocardializing cells extend lamellipodia and filopodia into the cushion tissue and reorganize their actin cytoskeleton from a cortical form to stress fibers; behaviors that are characteristic of polarized cells. In contrast, Lp/Lp littermates do not extend lamellipodia or filopodia into the cushion tissue, and their actin remains in a cortical form, suggesting that polarized cell migration of myocardializing cells is inhibited in Lp/Lp. Several other components of the PCP pathway are also localized in the outflow tract myocardium. In wild-type fetuses, the myocardializing cells coexpress RhoA and one of its downstream mediators, ROCK1. RhoA expression is disrupted in Lp/Lp, and is lost from the myocardial-cushion tissue interface, including the presumptive myocardializing cells. These data suggest that Vangl2 is required for the polarization and movement of myocardializing cells into the outflow tract cushions, and that RhoA and ROCK1 are downstream mediators of the PCP signaling pathway in the developing outflow tract.
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Affiliation(s)
- Helen M Phillips
- Institute of Human Genetics, University of Newcastle upon Tyne, UK
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Sakabe M, Ikeda K, Nakatani K, Kawada N, Imanaka-Yoshida K, Yoshida T, Yamagishi T, Nakajima Y. Rho kinases regulate endothelial invasion and migration during valvuloseptal endocardial cushion tissue formation. Dev Dyn 2005; 235:94-104. [PMID: 16342113 DOI: 10.1002/dvdy.20648] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Rho-associated kinase (ROCK) is a downstream effector of small Rho-GTPases, and phosphorylates several substrates to regulate cell functions, including actin cytoskeletal reorganization and cellular motility. Endothelial-mesenchymal transformation (EMT) is a critical event in the formation of valves and septa during cardiogenesis. It has been reported that ROCK plays an important role in the regulation of endocardial cell differentiation and migration during mouse cardiogenesis (Zhao and Rivkees [2004] Dev. Biol. 275:183-191). Immunohistochemistry showed that, during chick cardiogenesis, ROCK1 and -2 were expressed in the transforming and migrating endothelial/mesenchymal cells in the outflow tract (OT) and atrioventricular (AV) canal regions from which valvuloseptal endocardial cushion tissue would later develop. Treatment with Y27632, a specific ROCK inhibitor, of cultured AV explants or AV endothelial monolayers of stage 14-minus heart (preactivated stage for EMT) on three-dimensional collagen gel perturbed the seeding of mesenchymal cells into the gel lattice. In these experiments, Y27632 did not suppress the expression of an early transformation marker, smooth muscle alpha-actin. Moreover, Y27632 inhibited the mesenchymal invasion in stage 14-18 AV explants, in which endothelial cells had committed to undergo EMT. ML-9, a myosin light chain kinase inhibitor, also inhibited the mesenchymal invasion in cultured AV explants. These results suggest that ROCKs have a critical role in the mesenchymal cell invasion/migration that occurs at the late onset of EMT.
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Affiliation(s)
- Masahide Sakabe
- Department of Anoatomy, Graduate School of Medicine, Osaka City University, Osaka, Japan
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Curtis C, Hemmeryckx B, Haataja L, Senadheera D, Groffen J, Heisterkamp N. Scambio, a novel guanine nucleotide exchange factor for Rho. Mol Cancer 2004; 3:10. [PMID: 15107133 PMCID: PMC420252 DOI: 10.1186/1476-4598-3-10] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2003] [Accepted: 04/23/2004] [Indexed: 12/17/2022] Open
Abstract
Background Small GTPases of the Rho family are critical regulators of various cellular functions including actin cytoskeleton organization, activation of kinase cascades and mitogenesis. For this reason, a major objective has been to understand the mechanisms of Rho GTPase regulation. Here, we examine the function of a novel protein, Scambio, which shares homology with the DH-PH domains of several known guanine nucleotide exchange factors for Rho family members. Results Scambio is located on human chromosome 14q11.1, encodes a protein of around 181 kDa, and is highly expressed in both heart and skeletal muscle. In contrast to most DH-PH-domain containing proteins, it binds the activated, GTP-bound forms of Rac and Cdc42. However, it fails to associate with V14RhoA. Immunofluorescence studies indicate that Scambio and activated Rac3 colocalize in membrane ruffles at the cell periphery. In accordance with these findings, Scambio does not activate either Rac or Cdc42 but rather, stimulates guanine nucleotide exchange on RhoA and its close relative, RhoC. Conclusion Scambio associates with Rac in its activated conformation and functions as a guanine nucleotide exchange factor for Rho.
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Affiliation(s)
- Christina Curtis
- Division of Hematology/Oncology, Section of Molecular Carcinogenesis, Childrens Hospital Los Angeles Research Institute and the Keck School of Medicine of the University of Southern California, Los Angeles, California 90027, USA
- Current address: Molecular and Computational Biology Department, University of Southern California, Los Angeles, CA 90089, USA
| | - Bianca Hemmeryckx
- Division of Hematology/Oncology, Section of Molecular Carcinogenesis, Childrens Hospital Los Angeles Research Institute and the Keck School of Medicine of the University of Southern California, Los Angeles, California 90027, USA
| | - Leena Haataja
- Division of Hematology/Oncology, Section of Molecular Carcinogenesis, Childrens Hospital Los Angeles Research Institute and the Keck School of Medicine of the University of Southern California, Los Angeles, California 90027, USA
- Current address: Larry Hillblom Islet Research Center, UCLA Division of Endocrinology, Los Angeles, CA 90095-7073, USA
| | - Dinithi Senadheera
- Division of Hematology/Oncology, Section of Molecular Carcinogenesis, Childrens Hospital Los Angeles Research Institute and the Keck School of Medicine of the University of Southern California, Los Angeles, California 90027, USA
| | - John Groffen
- Division of Hematology/Oncology, Section of Molecular Carcinogenesis, Childrens Hospital Los Angeles Research Institute and the Keck School of Medicine of the University of Southern California, Los Angeles, California 90027, USA
| | - Nora Heisterkamp
- Division of Hematology/Oncology, Section of Molecular Carcinogenesis, Childrens Hospital Los Angeles Research Institute and the Keck School of Medicine of the University of Southern California, Los Angeles, California 90027, USA
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Zhang H, Toyofuku T, Kamei J, Hori M. GATA-4 regulates cardiac morphogenesis through transactivation of the N-cadherin gene. Biochem Biophys Res Commun 2004; 312:1033-8. [PMID: 14651975 DOI: 10.1016/j.bbrc.2003.11.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Cardia bifida is known to occur in animal models lacking the cardiogenic transcriptional factor GATA-4. The downstream target genes responsible for this cardiac deformity remain unknown, however. Treatment with small interfering RNAs (siRNA) specifically targeting GATA-4 into cardiac mesodermal cells led to the development of cardia bifida in chick embryos. RT-PCR using mRNAs extracted from cardiac tubes revealed that the GATA-4-specific siRNA selectively suppresses expression of N-cadherin mRNA, one of the genes essential for the single heart formation, without affecting other cardiac marker mRNAs. Analysis of the N-cadherin gene promoter activity using a luciferase reporter gene system and electrophoretic mobility shift assays revealed that GATA-4 binds directly to the N-cadherin gene promoter region, thereby transactivating its expression. We therefore concluded that the cardia bifida observed in the GATA-4-deleted model is caused by the transcriptional down-regulation of N-cadherin expression.
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Affiliation(s)
- Hong Zhang
- Department of Internal Medicine and Therapeutics, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Suita, 565-0871, Osaka, Japan
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