1
|
Frommelt J, Liu E, Bhaidani A, Hu B, Gao Y, Ye D, Lin F. Flat mount preparation for whole-mount fluorescent imaging of zebrafish embryos. Biol Open 2023; 12:bio060048. [PMID: 37746815 PMCID: PMC10373579 DOI: 10.1242/bio.060048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 06/23/2023] [Indexed: 09/26/2023] Open
Abstract
The zebrafish is a widely used model organism for biomedical research due to its ease of maintenance, external fertilization of embryos, rapid embryonic development, and availability of established genetic tools. One notable advantage of using zebrafish is the transparency of the embryos, which enables high-resolution imaging of specific cells, tissues, and structures through the use of transgenic and knock-in lines. However, as the embryo develops, multiple layers of tissue wrap around the lipid-enriched yolk, which can create a challenge to image tissues located deep within the embryo. While various methods are available, such as two-photon imaging, cryosectioning, vibratome sectioning, and micro-surgery, each of these has limitations. In this study, we present a novel deyolking method that allows for high-quality imaging of tissues that are obscured by other tissues and the yolk. Embryos are lightly fixed in 1% PFA to remove the yolk without damaging embryonic tissues and are then refixed in 4% PFA and mounted on custom-made bridged slides. This method offers a simple way to prepare imaging samples that can be subjected to further preparation, such as immunostaining. Furthermore, the bridged slides described in this study can be used for imaging tissue and organ preparations from various model organisms.
Collapse
Affiliation(s)
- Joseph Frommelt
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Emily Liu
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Afraz Bhaidani
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Bo Hu
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Yuanyuan Gao
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Ding Ye
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Fang Lin
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| |
Collapse
|
2
|
Chun YW, Miyamoto M, Williams CH, Neitzel LR, Silver-Isenstadt M, Cadar AG, Fuller DT, Fong DC, Liu H, Lease R, Kim S, Katagiri M, Durbin MD, Wang KC, Feaster TK, Sheng CC, Neely MD, Sreenivasan U, Cortes-Gutierrez M, Finn AV, Schot R, Mancini GMS, Ament SA, Ess KC, Bowman AB, Han Z, Bichell DP, Su YR, Hong CC. Impaired Reorganization of Centrosome Structure Underlies Human Infantile Dilated Cardiomyopathy. Circulation 2023; 147:1291-1303. [PMID: 36970983 PMCID: PMC10133173 DOI: 10.1161/circulationaha.122.060985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 02/22/2023] [Indexed: 03/29/2023]
Abstract
BACKGROUND During cardiomyocyte maturation, the centrosome, which functions as a microtubule organizing center in cardiomyocytes, undergoes dramatic structural reorganization where its components reorganize from being localized at the centriole to the nuclear envelope. This developmentally programmed process, referred to as centrosome reduction, has been previously associated with cell cycle exit. However, understanding of how this process influences cardiomyocyte cell biology, and whether its disruption results in human cardiac disease, remains unknown. We studied this phenomenon in an infant with a rare case of infantile dilated cardiomyopathy (iDCM) who presented with left ventricular ejection fraction of 18% and disrupted sarcomere and mitochondria structure. METHODS We performed an analysis beginning with an infant who presented with a rare case of iDCM. We derived induced pluripotent stem cells from the patient to model iDCM in vitro. We performed whole exome sequencing on the patient and his parents for causal gene analysis. CRISPR/Cas9-mediated gene knockout and correction in vitro were used to confirm whole exome sequencing results. Zebrafish and Drosophila models were used for in vivo validation of the causal gene. Matrigel mattress technology and single-cell RNA sequencing were used to characterize iDCM cardiomyocytes further. RESULTS Whole exome sequencing and CRISPR/Cas9 gene knockout/correction identified RTTN, the gene encoding the centrosomal protein RTTN (rotatin), as the causal gene underlying the patient's condition, representing the first time a centrosome defect has been implicated in a nonsyndromic dilated cardiomyopathy. Genetic knockdowns in zebrafish and Drosophila confirmed an evolutionarily conserved requirement of RTTN for cardiac structure and function. Single-cell RNA sequencing of iDCM cardiomyocytes showed impaired maturation of iDCM cardiomyocytes, which underlie the observed cardiomyocyte structural and functional deficits. We also observed persistent localization of the centrosome at the centriole, contrasting with expected programmed perinuclear reorganization, which led to subsequent global microtubule network defects. In addition, we identified a small molecule that restored centrosome reorganization and improved the structure and contractility of iDCM cardiomyocytes. CONCLUSIONS This study is the first to demonstrate a case of human disease caused by a defect in centrosome reduction. We also uncovered a novel role for RTTN in perinatal cardiac development and identified a potential therapeutic strategy for centrosome-related iDCM. Future study aimed at identifying variants in centrosome components may uncover additional contributors to human cardiac disease.
Collapse
Affiliation(s)
- Young Wook Chun
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
| | - Matthew Miyamoto
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
| | - Charles H. Williams
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
| | - Leif R. Neitzel
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
| | - Maya Silver-Isenstadt
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
| | - Adrian G. Cadar
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN 37201
| | - Daniela T. Fuller
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
| | - Daniel C. Fong
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
| | - Hanhan Liu
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
| | - Robert Lease
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Sungseek Kim
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN 37201
| | - Mikako Katagiri
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN 37201
| | - Matthew D. Durbin
- Division of Neonatology-Perinatology, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN 26202
| | - Kuo-Chen Wang
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
| | - Tromondae K. Feaster
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN 37201
| | - Calvin C. Sheng
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN 37201
| | - M. Diana Neely
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37201
| | - Urmila Sreenivasan
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
| | - Marcia Cortes-Gutierrez
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Aloke V. Finn
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
| | - Rachel Schot
- Division of Neonatology-Perinatology, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN 26202
| | - Grazia M. S. Mancini
- Department of Clinical Genetics, Erasmus University Medical Center (Erasmus MC), P.O. Box 2040, 3000 CA Rotterdam, The Netherlands
| | - Seth A. Ament
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kevin C. Ess
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN37201
| | - Aaron B. Bowman
- School of Health Sciences, Purdue University, West Lafayette, IN 47906
| | - Zhe Han
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
| | - David P. Bichell
- Department of Pediatric Cardiac Surgery, Vanderbilt University Medical Center, Nashville, TN 37201
| | - Yan Ru Su
- Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN 37201
| | - Charles C. Hong
- Division of Cardiovascular Medicine, Department of Medicine, University of Maryland Medical Center, Baltimore, MD 21201
| |
Collapse
|
3
|
Altered Expression of TMEM43 Causes Abnormal Cardiac Structure and Function in Zebrafish. Int J Mol Sci 2022; 23:ijms23179530. [PMID: 36076925 PMCID: PMC9455580 DOI: 10.3390/ijms23179530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 08/17/2022] [Accepted: 08/19/2022] [Indexed: 11/21/2022] Open
Abstract
Arrhythmogenic cardiomyopathy (ACM) is an inherited heart muscle disease caused by heterozygous missense mutations within the gene encoding for the nuclear envelope protein transmembrane protein 43 (TMEM43). The disease is characterized by myocyte loss and fibro-fatty replacement, leading to life-threatening ventricular arrhythmias and sudden cardiac death. However, the role of TMEM43 in the pathogenesis of ACM remains poorly understood. In this study, we generated cardiomyocyte-restricted transgenic zebrafish lines that overexpress eGFP-linked full-length human wild-type (WT) TMEM43 and two genetic variants (c.1073C>T, p.S358L; c.332C>T, p.P111L) using the Tol2-system. Overexpression of WT and p.P111L-mutant TMEM43 was associated with transcriptional activation of the mTOR pathway and ribosome biogenesis, and resulted in enlarged hearts with cardiomyocyte hypertrophy. Intriguingly, mutant p.S358L TMEM43 was found to be unstable and partially redistributed into the cytoplasm in embryonic and adult hearts. Moreover, both TMEM43 variants displayed cardiac morphological defects at juvenile stages and ultrastructural changes within the myocardium, accompanied by dysregulated gene expression profiles in adulthood. Finally, CRISPR/Cas9 mutants demonstrated an age-dependent cardiac phenotype characterized by heart enlargement in adulthood. In conclusion, our findings suggest ultrastructural remodeling and transcriptomic alterations underlying the development of structural and functional cardiac defects in TMEM43-associated cardiomyopathy.
Collapse
|
4
|
Da’as SI, Hasan W, Salem R, Younes N, Abdelrahman D, Mohamed IA, Aldaalis A, Temanni R, Mathew LS, Lorenz S, Yacoub M, Nomikos M, Nasrallah GK, Fakhro KA. Transcriptome Profile Identifies Actin as an Essential Regulator of Cardiac Myosin Binding Protein C3 Hypertrophic Cardiomyopathy in a Zebrafish Model. Int J Mol Sci 2022; 23:ijms23168840. [PMID: 36012114 PMCID: PMC9408294 DOI: 10.3390/ijms23168840] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 07/24/2022] [Accepted: 07/26/2022] [Indexed: 01/15/2023] Open
Abstract
Variants in cardiac myosin-binding protein C (cMyBP-C) are the leading cause of inherited hypertrophic cardiomyopathy (HCM), demonstrating the key role that cMyBP-C plays in the heart’s contractile machinery. To investigate the c-MYBPC3 HCM-related cardiac impairment, we generated a zebrafish mypbc3-knockout model. These knockout zebrafish displayed significant morphological heart alterations related to a significant decrease in ventricular and atrial diameters at systolic and diastolic states at the larval stages. Immunofluorescence staining revealed significant hyperplasia in the mutant’s total cardiac and ventricular cardiomyocytes. Although cardiac contractility was similar to the wild-type control, the ejection fraction was significantly increased in the mypbc3 mutants. At later stages of larval development, the mutants demonstrated an early cardiac phenotype of myocardium remodeling, concurrent cardiomyocyte hyperplasia, and increased ejection fraction as critical processes in HCM initiation to counteract the increased ventricular myocardial wall stress. The examination of zebrafish adults showed a thickened ventricular cardiac wall with reduced heart rate, swimming speed, and endurance ability in both the mypbc3 heterozygous and homozygous groups. Furthermore, heart transcriptome profiling showed a significant downregulation of the actin-filament-based process, indicating an impaired actin cytoskeleton organization as the main dysregulating factor associated with the early ventricular cardiac hypertrophy in the zebrafish mypbc3 HCM model.
Collapse
Affiliation(s)
- Sahar Isa Da’as
- Department of Human Genetics, Sidra Medicine, Doha P.O. Box 26999, Qatar
- Australian Regenerative Medicine Institute, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha P.O. Box 34110, Qatar
- Correspondence:
| | - Waseem Hasan
- Department of Human Genetics, Sidra Medicine, Doha P.O. Box 26999, Qatar
| | - Rola Salem
- Health Center, Qatar University, Doha P.O. Box 2713, Qatar
| | - Nadine Younes
- Department of Biomedical Sciences, College of Health Science, Member of QU Health, Qatar University, Doha P.O. Box 2713, Qatar
- Biomedical Research Center, Qatar University, Doha P.O. Box 2713, Qatar
| | - Doua Abdelrahman
- Department of Human Genetics, Sidra Medicine, Doha P.O. Box 26999, Qatar
| | - Iman A. Mohamed
- Australian Regenerative Medicine Institute, Monash University, Melbourne 3168, Australia
| | - Arwa Aldaalis
- Australian Regenerative Medicine Institute, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha P.O. Box 34110, Qatar
| | - Ramzi Temanni
- Integrated Genomics Services, Sidra Medicine, Doha P.O. Box 26999, Qatar
| | - Lisa Sara Mathew
- Integrated Genomics Services, Sidra Medicine, Doha P.O. Box 26999, Qatar
| | - Stephan Lorenz
- Integrated Genomics Services, Sidra Medicine, Doha P.O. Box 26999, Qatar
| | | | - Michail Nomikos
- College of Medicine, Member of QU Health, Qatar University, Doha P.O. Box 2713, Qatar
| | - Gheyath K. Nasrallah
- Department of Biomedical Sciences, College of Health Science, Member of QU Health, Qatar University, Doha P.O. Box 2713, Qatar
- Biomedical Research Center, Qatar University, Doha P.O. Box 2713, Qatar
| | - Khalid A. Fakhro
- Department of Human Genetics, Sidra Medicine, Doha P.O. Box 26999, Qatar
- Australian Regenerative Medicine Institute, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha P.O. Box 34110, Qatar
- Weill Cornell Medical College, Doha P.O. Box 24811, Qatar
| |
Collapse
|
5
|
Messerschmidt VL, Chintapula U, Bonetesta F, Laboy-Segarra S, Naderi A, Nguyen KT, Cao H, Mager E, Lee J. In vivo Evaluation of Non-viral NICD Plasmid-Loaded PLGA Nanoparticles in Developing Zebrafish to Improve Cardiac Functions. Front Physiol 2022; 13:819767. [PMID: 35283767 PMCID: PMC8906778 DOI: 10.3389/fphys.2022.819767] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 01/07/2022] [Indexed: 12/12/2022] Open
Abstract
In the era of the advanced nanomaterials, use of nanoparticles has been highlighted in biomedical research. However, the demonstration of DNA plasmid delivery with nanoparticles for in vivo gene delivery experiments must be carefully tested due to many possible issues, including toxicity. The purpose of the current study was to deliver a Notch Intracellular Domain (NICD)-encoded plasmid via poly(lactic-co-glycolic acid) (PLGA) nanoparticles and to investigate the toxic environmental side effects for an in vivo experiment. In addition, we demonstrated the target delivery to the endothelium, including the endocardial layer, which is challenging to manipulate gene expression for cardiac functions due to the beating heart and rapid blood pumping. For this study, we used a zebrafish animal model and exposed it to nanoparticles at varying concentrations to observe for specific malformations over time for toxic effects of PLGA nanoparticles as a delivery vehicle. Our nanoparticles caused significantly less malformations than the positive control, ZnO nanoparticles. Additionally, the NICD plasmid was successfully delivered by PLGA nanoparticles and significantly increased Notch signaling related genes. Furthermore, our image based deep-learning analysis approach evaluated that the antibody conjugated nanoparticles were successfully bound to the endocardium to overexpress Notch related genes and improve cardiac function such as ejection fraction, fractional shortening, and cardiac output. This research demonstrates that PLGA nanoparticle-mediated target delivery to upregulate Notch related genes which can be a potential therapeutic approach with minimum toxic effects.
Collapse
Affiliation(s)
- Victoria L Messerschmidt
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX, United States.,University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Uday Chintapula
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX, United States.,University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Fabrizio Bonetesta
- Department of Biological Sciences, University of North Texas, Denton, TX, United States
| | - Samantha Laboy-Segarra
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX, United States.,University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Amir Naderi
- Department of Electrical Engineering and Computer Science, University of California, Irvine, Irvine, CA, United States
| | - Kytai T Nguyen
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX, United States.,University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Hung Cao
- Department of Electrical Engineering and Computer Science, University of California, Irvine, Irvine, CA, United States
| | - Edward Mager
- Department of Biological Sciences, University of North Texas, Denton, TX, United States
| | - Juhyun Lee
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX, United States.,University of Texas Southwestern Medical Center, Dallas, TX, United States
| |
Collapse
|
6
|
Myocardial Afterload Is a Key Biomechanical Regulator of Atrioventricular Myocyte Differentiation in Zebrafish. J Cardiovasc Dev Dis 2022; 9:jcdd9010022. [PMID: 35050232 PMCID: PMC8779957 DOI: 10.3390/jcdd9010022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/05/2022] [Accepted: 01/06/2022] [Indexed: 02/05/2023] Open
Abstract
Heart valve development is governed by both genetic and biomechanical inputs. Prior work has demonstrated that oscillating shear stress associated with blood flow is required for normal atrioventricular (AV) valve development. Cardiac afterload is defined as the pressure the ventricle must overcome in order to pump blood throughout the circulatory system. In human patients, conditions of high afterload can cause valve pathology. Whether high afterload adversely affects embryonic valve development remains poorly understood. Here we describe a zebrafish model exhibiting increased myocardial afterload, caused by vasopressin, a vasoconstrictive drug. We show that the application of vasopressin reliably produces an increase in afterload without directly acting on cardiac tissue in zebrafish embryos. We have found that increased afterload alters the rate of growth of the cardiac chambers and causes remodeling of cardiomyocytes. Consistent with pathology seen in patients with clinically high afterload, we see defects in both the form and the function of the valve leaflets. Our results suggest that valve defects are due to changes in atrioventricular myocyte signaling, rather than pressure directly acting on the endothelial valve leaflet cells. Cardiac afterload should therefore be considered a biomechanical factor that particularly impacts embryonic valve development.
Collapse
|
7
|
Xu R, Du S. Overexpression of Lifeact-GFP Disrupts F-Actin Organization in Cardiomyocytes and Impairs Cardiac Function. Front Cell Dev Biol 2021; 9:746818. [PMID: 34765602 PMCID: PMC8576398 DOI: 10.3389/fcell.2021.746818] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 10/07/2021] [Indexed: 11/28/2022] Open
Abstract
Lifeact-GFP is a frequently used molecular probe to study F-actin structure and dynamic assembly in living cells. In this study, we generated transgenic zebrafish models expressing Lifeact-GFP specifically in cardiac muscles to investigate the effect of Lifeact-GFP on heart development and its application to study cardiomyopathy. The data showed that transgenic zebrafish with low to moderate levels of Lifeact-GFP expression could be used as a good model to study contractile dynamics of actin filaments in cardiac muscles in vivo. Using this model, we demonstrated that loss of Smyd1b, a lysine methyltransferase, disrupted F-actin filament organization in cardiomyocytes of zebrafish embryos. Our studies, however, also demonstrated that strong Lifeact-GFP expression in cardiomyocytes was detrimental to actin filament organization in cardiomyocytes that led to pericardial edema and early embryonic lethality of zebrafish embryos. Collectively, these data suggest that although Lifeact-GFP is a good probe for visualizing F-actin dynamics, transgenic models need to be carefully evaluated to avoid artifacts induced by Lifeact-GFP overexpression.
Collapse
Affiliation(s)
- Rui Xu
- Department of Biochemistry and Molecular Biology, Institute of Marine and Environmental Technology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Shaojun Du
- Department of Biochemistry and Molecular Biology, Institute of Marine and Environmental Technology, University of Maryland School of Medicine, Baltimore, MD, United States
| |
Collapse
|
8
|
Peng Y, Wang W, Fang Y, Hu H, Chang N, Pang M, Hu YF, Li X, Long H, Xiong JW, Zhang R. Inhibition of TGF-β/Smad3 Signaling Disrupts Cardiomyocyte Cell Cycle Progression and Epithelial-Mesenchymal Transition-Like Response During Ventricle Regeneration. Front Cell Dev Biol 2021; 9:632372. [PMID: 33816481 PMCID: PMC8010688 DOI: 10.3389/fcell.2021.632372] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 02/03/2021] [Indexed: 12/11/2022] Open
Abstract
Unlike mammals, zebrafish can regenerate injured hearts even in the adult stage. Cardiac regeneration requires the coordination of cardiomyocyte (CM) proliferation and migration. The TGF-β/Smad3 signaling pathway has been implicated in cardiac regeneration, but the molecular mechanisms by which this pathway regulates CM proliferation and migration have not been fully illustrated. Here, we investigated the function of TGF-β/Smad3 signaling in a zebrafish model of ventricular ablation. Multiple components of this pathway were upregulated/activated after injury. Utilizing a specific inhibitor of Smad3, we detected an increased ratio of unrecovered hearts. Transcriptomic analysis suggested that the TGF-β/Smad3 signaling pathway could affect CM proliferation and migration. Further analysis demonstrated that the CM cell cycle was disrupted and the epithelial–mesenchymal transition (EMT)-like response was impaired, which limited cardiac regeneration. Altogether, our study reveals an important function of TGF-β/Smad3 signaling in CM cell cycle progression and EMT process during zebrafish ventricle regeneration.
Collapse
Affiliation(s)
- Yuanyuan Peng
- School of Life Sciences, Fudan University, Shanghai, China
| | - Wenyuan Wang
- School of Life Sciences, Fudan University, Shanghai, China
| | - Yunzheng Fang
- School of Life Sciences, Fudan University, Shanghai, China
| | - Haichen Hu
- Shanghai Medical College, Fudan University, Shanghai, China
| | - Nannan Chang
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, Beijing, China
| | - Meijun Pang
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, Beijing, China
| | - Ye-Fan Hu
- School of Life Sciences, Fudan University, Shanghai, China.,Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, China.,School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, China
| | - Xueyu Li
- School of Life Sciences, Fudan University, Shanghai, China
| | - Han Long
- School of Life Sciences, Fudan University, Shanghai, China
| | - Jing-Wei Xiong
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Peking University, Beijing, China
| | - Ruilin Zhang
- School of Basic Medical Sciences, Wuhan University, Wuhan, China
| |
Collapse
|
9
|
Rostam N, Dosch R. Glyoxal Fixation as an Alternative for Zebrafish Embryo Immunostaining. Methods Mol Biol 2021; 2218:245-252. [PMID: 33606236 DOI: 10.1007/978-1-0716-0970-5_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Immunohistochemistry has been widely used as a robust technique to determine the cellular and subcellular localization of proteins. This information ultimately helps to understand the function of these proteins and how biological processes are regulated. Antibodies applicable for labeling in zebrafish are limited, making immuno-staining challenging. Recently glyoxal fixation was rediscovered in tissue culture, mouse, rat, and Drosophila, expanding the list of effective antibodies for these species. Here, we compare a protocol for zebrafish staining using glyoxal as a fixative agent with PFA. We demonstrate that glyoxal fixation improves the antigenicity of some epitopes thereby increasing the number of useful antibodies in zebrafish.
Collapse
Affiliation(s)
- Nadia Rostam
- Institute of Human Genetics, University of Göttingen Medical Center, Georg-August-Universität, Göttingen, Germany.
- Department of Developmental Biology, Johann-Friedrich-Blumenbach Institute of Zoology and Anthropology, Göttingen Center of Molecular Biosciences, Göttingen, Germany.
- Department of Biology, College of Science, University of Sulaimani (UoS), Sulaimaniyah, Iraq.
| | - Roland Dosch
- Institute for Developmental Biochemistry, University of Göttingen Medical Center, Georg-August-Universität, Göttingen, Germany.
| |
Collapse
|
10
|
PGAP3 Associated with Hyperphosphatasia with Mental Retardation Plays a Novel Role in Brain Morphogenesis and Neuronal Wiring at Early Development. Cells 2020; 9:cells9081782. [PMID: 32726939 PMCID: PMC7569840 DOI: 10.3390/cells9081782] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/05/2020] [Accepted: 07/11/2020] [Indexed: 12/30/2022] Open
Abstract
Recessive mutations in Post-GPI attachment to proteins 3 (PGAP3) cause the rare neurological disorder hyperphosphatasia with mental retardation syndrome 4 type (HPMRS4). Here, we report a novel homozygous nonsense mutation in PGAP3 (c.265C>T-p.Gln89*), in a 3-year-old boy with unique novel clinical features. These include decreased intrauterine fetal movements, dysgenesis of the corpus callosum, olfactory bulb agenesis, dysmorphic features, cleft palate, left ear constriction, global developmental delay, and hypotonia. The zebrafish functional modeling of PGAP3 loss resulted in HPMRS4-like features, including structural brain abnormalities, dysmorphic cranial and facial features, hypotonia, and seizure-like behavior. Remarkably, morphants displayed defective neural tube formation during the early stages of nervous system development, affecting brain morphogenesis. The significant aberrant midbrain and hindbrain formation demonstrated by separation of the left and right tectal ventricles, defects in the cerebellar corpus, and caudal hindbrain formation disrupted oligodendrocytes expression leading to shorter motor neurons axons. Assessment of zebrafish neuromuscular responses revealed epileptic-like movements at early development, followed by seizure-like behavior, loss of touch response, and hypotonia, mimicking the clinical phenotype human patients. Altogether, we report a novel pathogenic PGAP3 variant associated with unique phenotypic hallmarks, which may be related to the gene's novel role in brain morphogenesis and neuronal wiring.
Collapse
|
11
|
Ding Y, Dvornikov AV, Ma X, Zhang H, Wang Y, Lowerison M, Packard RR, Wang L, Chen J, Zhang Y, Hsiai T, Lin X, Xu X. Haploinsufficiency of mechanistic target of rapamycin ameliorates bag3 cardiomyopathy in adult zebrafish. Dis Model Mech 2019; 12:dmm040154. [PMID: 31492659 PMCID: PMC6826022 DOI: 10.1242/dmm.040154] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 08/28/2019] [Indexed: 12/14/2022] Open
Abstract
The adult zebrafish is an emerging vertebrate model for studying human cardiomyopathies; however, whether the simple zebrafish heart can model different subtypes of cardiomyopathies, such as dilated cardiomyopathy (DCM), remains elusive. Here, we generated and characterized an inherited DCM model in adult zebrafish and used this model to search for therapeutic strategies. We employed transcription activator-like effector nuclease (TALEN) genome editing technology to generate frame-shift mutants for the zebrafish ortholog of human BCL2-associated athanogene 3 (BAG3), an established DCM-causative gene. As in mammals, the zebrafish bag3 homozygous mutant (bag3e2/e2 ) exhibited aberrant proteostasis, as indicated by impaired autophagy flux and elevated ubiquitinated protein aggregation. Through comprehensive phenotyping analysis of the mutant, we identified phenotypic traits that resembled DCM phenotypes in mammals, including cardiac chamber enlargement, reduced ejection fraction characterized by increased end-systolic volume/body weight (ESV/BW), and reduced contractile myofibril activation kinetics. Nonbiased transcriptome analysis identified the hyperactivation of the mechanistic target of rapamycin (mTOR) signaling in bag3e2/e2 mutant hearts. Further genetic studies showed that mtorxu015/+ , an mTOR haploinsufficiency mutant, repaired abnormal proteostasis, improved cardiac function and rescued the survival of the bag3e2/e2 mutant. This study established the bag3e2/e2 mutant as a DCM model in adult zebrafish and suggested mtor as a candidate therapeutic target gene for BAG3 cardiomyopathy.
Collapse
Affiliation(s)
- Yonghe Ding
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Alexey V Dvornikov
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Xiao Ma
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55905, USA
- Center for Clinical and Translational Science, Mayo Clinic, Rochester, MN 55905, USA
- Mayo Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN 55905, USA
| | - Hong Zhang
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55905, USA
- Clinical Center for Gene Diagnosis and Therapy, the Second Xiangya Hospital of Central South University, Changsha, China 410011
| | - Yong Wang
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55905, USA
- Institute of Life Science, Beijing University of Chinese Medicine, Beijing, China 100029
| | | | - Rene R Packard
- School of Medicine, University of California Los Angeles, Los Angeles, CA 90073, USA
| | - Lei Wang
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Jun Chen
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN 55905, USA
| | - Yuji Zhang
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Tzung Hsiai
- School of Medicine, University of California Los Angeles, Los Angeles, CA 90073, USA
| | - Xueying Lin
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Xiaolei Xu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55905, USA
- Center for Clinical and Translational Science, Mayo Clinic, Rochester, MN 55905, USA
- Mayo Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN 55905, USA
| |
Collapse
|
12
|
smarce1 mutants have a defective endocardium and an increased expression of cardiac transcription factors in zebrafish. Sci Rep 2018; 8:15369. [PMID: 30337622 PMCID: PMC6194089 DOI: 10.1038/s41598-018-33746-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 10/05/2018] [Indexed: 12/11/2022] Open
Abstract
SWI/SNF or BAF chromatin-remodeling complexes are polymorphic assemblies of homologous subunit families that remodel nucleosomes and facilitate tissue-specific gene regulation during development. BAF57/SMARCE1 is a BAF complex subunit encoded in animals by a single gene and is a component of all mammalian BAF complexes. In vivo, the loss of SMARCE1 would lead to the formation of deficient combinations of the complex which might present limited remodeling activities. To address the specific contribution of SMARCE1 to the function of the BAF complex, we generated CRISPR/Cas9 mutations of smarce1 in zebrafish. Smarce1 mutants showed visible defects at 72 hpf, including smaller eyes, abnormal body curvature and heart abnormalities. Gene expression analysis revealed that the mutant embryos displayed defects in endocardial development since early stages, which led to the formation of a misshapen heart tube. The severe morphological and functional cardiac problems observed at 4 dpf were correlated with the substantially increased expression of different cardiac transcription factors. Additionally, we showed that Smarce1 binds to cis-regulatory regions of the gata5 gene and is necessary for the recruitment of the BAF complex to these regions.
Collapse
|
13
|
Ahlberg G, Refsgaard L, Lundegaard PR, Andreasen L, Ranthe MF, Linscheid N, Nielsen JB, Melbye M, Haunsø S, Sajadieh A, Camp L, Olesen SP, Rasmussen S, Lundby A, Ellinor PT, Holst AG, Svendsen JH, Olesen MS. Rare truncating variants in the sarcomeric protein titin associate with familial and early-onset atrial fibrillation. Nat Commun 2018; 9:4316. [PMID: 30333491 PMCID: PMC6193003 DOI: 10.1038/s41467-018-06618-y] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 09/17/2018] [Indexed: 12/13/2022] Open
Abstract
A family history of atrial fibrillation constitutes a substantial risk of developing the disease, however, the pathogenesis of this complex disease is poorly understood. We perform whole-exome sequencing on 24 families with at least three family members diagnosed with atrial fibrillation (AF) and find that titin-truncating variants (TTNtv) are significantly enriched in these patients (P = 1.76 × 10−6). This finding is replicated in an independent cohort of early-onset lone AF patients (n = 399; odds ratio = 36.8; P = 4.13 × 10−6). A CRISPR/Cas9 modified zebrafish carrying a truncating variant of titin is used to investigate TTNtv effect in atrial development. We observe compromised assembly of the sarcomere in both atria and ventricle, longer PR interval, and heterozygous adult zebrafish have a higher degree of fibrosis in the atria, indicating that TTNtv are important risk factors for AF. This aligns with the early onset of the disease and adds an important dimension to the understanding of the molecular predisposition for AF. Common genetic variants in structural proteins contribute to risk of atrial fibrillation (AF). Here, using whole-exome sequencing, the authors identify rare truncating variants in TTN that associate with familial and early-onset AF and show defects in cardiac sarcomere assembly in ttn.2-mutant zebrafish.
Collapse
Affiliation(s)
- Gustav Ahlberg
- Laboratory for Molecular Cardiology, Department of Cardiology, The Heart Centre, Rigshospitalet, University Hospital of Copenhagen, Copenhagen, 2100 Ø, Denmark.,Department of Biomedical Sciences, University of Copenhagen, Copenhagen, 2200 N, Denmark
| | - Lena Refsgaard
- Laboratory for Molecular Cardiology, Department of Cardiology, The Heart Centre, Rigshospitalet, University Hospital of Copenhagen, Copenhagen, 2100 Ø, Denmark.,Department of Biomedical Sciences, University of Copenhagen, Copenhagen, 2200 N, Denmark
| | - Pia R Lundegaard
- Laboratory for Molecular Cardiology, Department of Cardiology, The Heart Centre, Rigshospitalet, University Hospital of Copenhagen, Copenhagen, 2100 Ø, Denmark.,Department of Biomedical Sciences, University of Copenhagen, Copenhagen, 2200 N, Denmark
| | - Laura Andreasen
- Laboratory for Molecular Cardiology, Department of Cardiology, The Heart Centre, Rigshospitalet, University Hospital of Copenhagen, Copenhagen, 2100 Ø, Denmark.,Department of Biomedical Sciences, University of Copenhagen, Copenhagen, 2200 N, Denmark
| | - Mattis F Ranthe
- Department of Epidemiology Research, Statens Serum Institute, Copenhagen, 2300 S, Denmark
| | - Nora Linscheid
- Cardiac Proteomics Group, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2200 N, Denmark.,Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2200 N, Denmark
| | - Jonas B Nielsen
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2200 N, Denmark
| | - Mads Melbye
- Department of Epidemiology Research, Statens Serum Institute, Copenhagen, 2300 S, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2200 N, Denmark.,Department of Medicine, Stanford University School of Medicine, Stanford, 94305, CA, USA
| | - Stig Haunsø
- Laboratory for Molecular Cardiology, Department of Cardiology, The Heart Centre, Rigshospitalet, University Hospital of Copenhagen, Copenhagen, 2100 Ø, Denmark
| | - Ahmad Sajadieh
- Department of Cardiology, Copenhagen University Hospital, Bispebjerg, Copenhagen, 2400, Denmark
| | - Lu Camp
- The Lundbeck Foundation Centre for Applied Medical Genomics in Personalized Disease Prediction, Prevention and Care, Copenhagen, 2200 N, Denmark
| | - Søren-Peter Olesen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, 2200 N, Denmark
| | - Simon Rasmussen
- Department of Bio and Health Informatics, Technical University of Denmark, Kgs, Lyngby, 2800, Denmark
| | - Alicia Lundby
- Cardiac Proteomics Group, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2200 N, Denmark.,Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2200 N, Denmark
| | - Patrick T Ellinor
- Cardiovascular Research Centre, Massachusetts General Hospital, Boston, 02114, MA, USA.,Program in Population and Medical Genetics, The Broad Institute of Harvard and MIT, Cambridge, 02114, MA, USA
| | - Anders G Holst
- Laboratory for Molecular Cardiology, Department of Cardiology, The Heart Centre, Rigshospitalet, University Hospital of Copenhagen, Copenhagen, 2100 Ø, Denmark
| | - Jesper H Svendsen
- Laboratory for Molecular Cardiology, Department of Cardiology, The Heart Centre, Rigshospitalet, University Hospital of Copenhagen, Copenhagen, 2100 Ø, Denmark.,Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2200 N, Denmark
| | - Morten S Olesen
- Laboratory for Molecular Cardiology, Department of Cardiology, The Heart Centre, Rigshospitalet, University Hospital of Copenhagen, Copenhagen, 2100 Ø, Denmark. .,Department of Biomedical Sciences, University of Copenhagen, Copenhagen, 2200 N, Denmark.
| |
Collapse
|
14
|
Zebrafish VCAP1X2 regulates cardiac contractility and proliferation of cardiomyocytes and epicardial cells. Sci Rep 2018; 8:7856. [PMID: 29777134 PMCID: PMC5959901 DOI: 10.1038/s41598-018-26110-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 05/01/2018] [Indexed: 01/08/2023] Open
Abstract
Sarcomeric signaling complexes are important to sustain proper sarcomere structure and function, however, the mechanisms underlying these processes are not fully elucidated. In a gene trap experiment, we found that vascular cell adhesion protein 1 isoform X2 (VCAP1X2) mutant embryos displayed a dilated cardiomyopathy phenotype, including reduced cardiac contractility, enlarged ventricular chamber and thinned ventricular compact layer. Cardiomyocyte and epicardial cell proliferation was decreased in the mutant heart ventricle, as was the expression of pAKT and pERK. Contractile dysfunction in the mutant was caused by sarcomeric disorganization, including sparse myofilament, blurred Z-disc, and decreased gene expression for sarcomere modulators (smyd1b, mypn and fhl2a), sarcomeric proteins (myh6, myh7, vmhcl and tnnt2a) and calcium regulators (ryr2b and slc8a1a). Treatment of PI3K activator restored Z-disc alignment while injection of smyd1b mRNA restored Z-disc alignment, contractile function and cardiomyocyte proliferation in ventricles of VCAP1X2 mutant embryos. Furthermore, injection of VCAP1X2 variant mRNA rescued all phenotypes, so long as two cytosolic tyrosines were left intact. Our results reveal two tyrosine residues located in the VCAP1X2 cytoplasmic domain are essential to regulate cardiac contractility and the proliferation of ventricular cardiomyocytes and epicardial cells through modulating pAKT and pERK expression levels.
Collapse
|
15
|
Cheng F, Miao L, Wu Q, Gong X, Xiong J, Zhang J. Vinculin b deficiency causes epicardial hyperplasia and coronary vessel disorganization in zebrafish. Development 2016; 143:3522-3531. [PMID: 27578788 DOI: 10.1242/dev.132936] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 07/26/2016] [Indexed: 12/29/2022]
Abstract
Coronary vessel development is a highly coordinated process during heart formation. Abnormal development and dysfunction of the coronary network are contributory factors in the majority of heart disease. Understanding the molecular mechanisms that regulate coronary vessel formation is crucial for preventing and treating the disease. We report a zebrafish gene-trap vinculin b (vclb) mutant that displays abnormal coronary vessel development among multiple cardiac defects. The mutant shows overproliferation of epicardium-derived cells and disorganization of coronary vessels, and they eventually die off at juvenile stages. Mechanistically, Vclb deficiency results in the release of another cytoskeletal protein, paxillin, from the Vclb complex and the upregulation of ERK and FAK phosphorylation in epicardium and endocardium, causing disorganization of endothelial cells and pericytes during coronary vessel development. By contrast, cardiac muscle development is relatively normal, probably owing to redundancy with Vcla, a vinculin paralog that is expressed in the myocardium but not epicardium. Together, our results reveal a previously unappreciated function of vinculin in epicardium and endocardium and reinforce the notion that well-balanced FAK activity is essential for coronary vessel development.
Collapse
Affiliation(s)
- Feng Cheng
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China University of Chinese Academy of Sciences, Beijing 100049, China
| | - Liyun Miao
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qing Wu
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100871, China
| | - Xia Gong
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jingwei Xiong
- Institute of Molecular Medicine, Beijing Key Laboratory of Cardiometabolic Molecular Medicine and State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100871, China
| | - Jian Zhang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| |
Collapse
|
16
|
Foglia MJ, Cao J, Tornini VA, Poss KD. Multicolor mapping of the cardiomyocyte proliferation dynamics that construct the atrium. Development 2016; 143:1688-96. [PMID: 26989176 DOI: 10.1242/dev.136606] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 03/08/2016] [Indexed: 01/13/2023]
Abstract
The orchestrated division of cardiomyocytes assembles heart chambers of distinct morphology. To understand the structural divergence of the cardiac chambers, we determined the contributions of individual embryonic cardiomyocytes to the atrium in zebrafish by multicolor fate-mapping and we compare our analysis to the established proliferation dynamics of ventricular cardiomyocytes. We find that most atrial cardiomyocytes become rod-shaped in the second week of life, generating a single-muscle-cell-thick myocardial wall with a striking webbed morphology. Inner pectinate myofibers form mainly by direct branching, unlike delamination events that create ventricular trabeculae. Thus, muscle clones assembling the atrial chamber can extend from wall to lumen. As zebrafish mature, atrial wall cardiomyocytes proliferate laterally to generate cohesive patches of diverse shapes and sizes, frequently with dominant clones that comprise 20-30% of the wall area. A subpopulation of cardiomyocytes that transiently express atrial myosin heavy chain (amhc) contributes substantially to specific regions of the ventricle, suggesting an unappreciated level of plasticity during chamber formation. Our findings reveal proliferation dynamics and fate decisions of cardiomyocytes that produce the distinct architecture of the atrium.
Collapse
Affiliation(s)
- Matthew J Foglia
- Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Jingli Cao
- Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Valerie A Tornini
- Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Kenneth D Poss
- Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA
| |
Collapse
|
17
|
Hirth S, Bühler A, Bührdel JB, Rudeck S, Dahme T, Rottbauer W, Just S. Paxillin and Focal Adhesion Kinase (FAK) Regulate Cardiac Contractility in the Zebrafish Heart. PLoS One 2016; 11:e0150323. [PMID: 26954676 PMCID: PMC4782988 DOI: 10.1371/journal.pone.0150323] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 02/11/2016] [Indexed: 01/28/2023] Open
Abstract
An orchestrated interplay of adaptor and signaling proteins at mechano-sensitive sites is essential to maintain cardiac contractility and when defective leads to heart failure. We recently showed that Integrin-linked Kinase (ILK), ß-Parvin and PINCH form the IPP-complex to grant tuned Protein Kinase B (PKB) signaling in the heart. Loss of one of the IPP-complex components results in destabilization of the whole complex, defective PKB signaling and finally heart failure. Two components of IPP, ILK and ß-Parvin directly bind to Paxillin; however, the impact of this direct interaction on the maintenance of heart function is not known yet. Here, we show that targeted gene inactivation of Paxillin results in progressive decrease of cardiac contractility and heart failure in zebrafish without affecting IPP-complex stability and PKB phosphorylation. However, we found that Paxillin deficiency leads to the destabilization of its known binding partner Focal Adhesion Kinase (FAK) and vice versa resulting in degradation of Vinculin and thereby heart failure. Our findings highlight an essential role of Paxillin and FAK in controlling cardiac contractility via the recruitment of Vinculin to mechano-sensitive sites in cardiomyocytes.
Collapse
Affiliation(s)
- Sofia Hirth
- Molecular Cardiology, University of Ulm, Ulm, Germany
| | - Anja Bühler
- Molecular Cardiology, University of Ulm, Ulm, Germany
| | | | - Steven Rudeck
- Molecular Cardiology, University of Ulm, Ulm, Germany
| | - Tillman Dahme
- Department of Medicine II, University of Ulm, Ulm, Germany
| | - Wolfgang Rottbauer
- Department of Medicine II, University of Ulm, Ulm, Germany
- * E-mail: (SJ); (WR)
| | - Steffen Just
- Molecular Cardiology, University of Ulm, Ulm, Germany
- * E-mail: (SJ); (WR)
| |
Collapse
|
18
|
Verstraeten B, van Hengel J, Huysseune A. Beta-Catenin and Plakoglobin Expression during Zebrafish Tooth Development and Replacement. PLoS One 2016; 11:e0148114. [PMID: 26938059 PMCID: PMC4777446 DOI: 10.1371/journal.pone.0148114] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 02/17/2016] [Indexed: 11/18/2022] Open
Abstract
We analyzed the protein distribution of two cadherin-associated molecules, plakoglobin and β-catenin, during the different stages of tooth development and tooth replacement in zebrafish. Plakoglobin was detected at the plasma membrane already at the onset of tooth development in the epithelial cells of the tooth. This pattern remained unaltered during further tooth development. The mesenchymal cells only showed plakoglobin from cytodifferentiation onwards. Plakoglobin 1a morpholino-injected embryos showed normal tooth development with proper initiation and differentiation. Although plakoglobin is clearly present during normal odontogenesis, the loss of plakoglobin 1a does not influence tooth development. β-catenin was found at the cell borders of all cells of the successional lamina but also in the nuclei of surrounding mesenchymal cells. Only membranous, not nuclear, β-catenin, was found during morphogenesis stage. However, during cytodifferentiation stage, both nuclear and membrane-bound β-catenin was detected in the layers of the enamel organ as well as in the differentiating odontoblasts. Nuclear β-catenin is an indication of an activated Wnt pathway, therefore suggesting a possible role for Wnt signalling during zebrafish tooth development and replacement.
Collapse
Affiliation(s)
| | - Jolanda van Hengel
- Molecular Cell Biology Unit, Department for Molecular Biomedical Research, VIB Ghent, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Ann Huysseune
- Evolutionary Developmental Biology, Ghent University, Ghent, Belgium
- * E-mail:
| |
Collapse
|
19
|
Bühler A, Kustermann M, Bummer T, Rottbauer W, Sandri M, Just S. Atrogin-1 Deficiency Leads to Myopathy and Heart Failure in Zebrafish. Int J Mol Sci 2016; 17:ijms17020187. [PMID: 26840306 PMCID: PMC4783921 DOI: 10.3390/ijms17020187] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/13/2016] [Accepted: 01/18/2016] [Indexed: 12/21/2022] Open
Abstract
Orchestrated protein synthesis and degradation is fundamental for proper cell function. In muscle, impairment of proteostasis often leads to severe cellular defects finally interfering with contractile function. Here, we analyze for the first time the role of Atrogin-1, a muscle-specific E3 ubiquitin ligase known to be involved in the regulation of protein degradation via the ubiquitin proteasome and the autophagy/lysosome systems, in the in vivo model system zebrafish (Danio rerio). We found that targeted inactivation of zebrafish Atrogin-1 leads to progressive impairment of heart and skeletal muscle function and disruption of muscle structure without affecting early cardiogenesis and skeletal muscle development. Autophagy is severely impaired in Atrogin-1-deficient zebrafish embryos resulting in the disturbance of the cytoarchitecture of cardiomyocytes and skeletal muscle cells. These observations are consistent with molecular and ultrastructural findings in an Atrogin-1 knockout mouse and demonstrate that the zebrafish is a suitable vertebrate model to study the molecular mechanisms of Atrogin-1-mediated autophagic muscle pathologies and to screen for novel therapeutically active substances in high-throughput in vivo small compound screens (SCS).
Collapse
Affiliation(s)
- Anja Bühler
- Molecular Cardiology, University of Ulm, 89081 Ulm, Germany.
| | | | - Tiziana Bummer
- Molecular Cardiology, University of Ulm, 89081 Ulm, Germany.
| | - Wolfgang Rottbauer
- Department of Internal Medicine II, University of Ulm, 89081 Ulm, Germany.
| | - Marco Sandri
- Department of Biomedical Sciences, University of Padova, 35129 Padova, Italy.
| | - Steffen Just
- Molecular Cardiology, University of Ulm, 89081 Ulm, Germany.
| |
Collapse
|
20
|
Yang J, Shah S, Olson TM, Xu X. Modeling GATAD1-Associated Dilated Cardiomyopathy in Adult Zebrafish. J Cardiovasc Dev Dis 2016; 3. [PMID: 28955713 PMCID: PMC5611887 DOI: 10.3390/jcdd3010006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Animal models have played a critical role in validating human dilated cardiomyopathy (DCM) genes, particularly those that implicate novel mechanisms for heart failure. However, the disease phenotype may be delayed due to age-dependent penetrance. For this reason, we generated an adult zebrafish model, which is a simpler vertebrate model with higher throughput than rodents. Specifically, we studied the zebrafish homologue of GATAD1, a recently identified gene for adult-onset autosomal recessive DCM. We showed cardiac expression of gatad1 transcripts, by whole mount in situ hybridization in zebrafish embryos, and demonstrated nuclear and sarcomeric I-band subcellular localization of Gatad1 protein in cardiomyocytes, by injecting a Tol2 plasmid encoding fluorescently-tagged Gatad1. We next generated gatad1 knock-out fish lines by TALEN technology and a transgenic fish line that expresses the human DCM GATAD1-S102P mutation in cardiomyocytes. Under stress conditions, longitudinal studies uncovered heart failure (HF)-like phenotypes in stable KO mutants and a tendency toward HF phenotypes in transgenic lines. Based on these efforts of studying a gene-based inherited cardiomyopathy model, we discuss the strengths and bottlenecks of adult zebrafish as a new vertebrate model for assessing candidate cardiomyopathy genes.
Collapse
Affiliation(s)
- Jingchun Yang
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, 200 First St. SW Rochester, MN 55905, USA; (J.Y.); (S.S.)
| | - Sahrish Shah
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, 200 First St. SW Rochester, MN 55905, USA; (J.Y.); (S.S.)
| | - Timothy M. Olson
- Department of Internal Medicine, Division of Cardiovascular Diseases, Mayo Clinic College of Medicine, 200 First St. SW Rochester, MN 55905, USA;
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Cardiology, Mayo Clinic College of Medicine, 200 First St. SW Rochester, MN 55905, USA
| | - Xiaolei Xu
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, 200 First St. SW Rochester, MN 55905, USA; (J.Y.); (S.S.)
- Department of Internal Medicine, Division of Cardiovascular Diseases, Mayo Clinic College of Medicine, 200 First St. SW Rochester, MN 55905, USA;
- Correspondence: ; Tel.: +1-507-284-0685; Fax: +1-507-538-6418
| |
Collapse
|
21
|
Yang J, Shih YH, Xu X. Understanding cardiac sarcomere assembly with zebrafish genetics. Anat Rec (Hoboken) 2015; 297:1681-93. [PMID: 25125181 DOI: 10.1002/ar.22975] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Revised: 05/12/2014] [Accepted: 05/13/2014] [Indexed: 01/06/2023]
Abstract
Mutations in sarcomere genes have been found in many inheritable human diseases, including hypertrophic cardiomyopathy. Elucidating the molecular mechanisms of sarcomere assembly shall facilitate understanding of the pathogenesis of sarcomere-based cardiac disease. Recently, biochemical and genomic studies have identified many new genes encoding proteins that localize to the sarcomere. However, their precise functions in sarcomere assembly and sarcomere-based cardiac disease are unknown. Here, we review zebrafish as an emerging vertebrate model for these studies. We summarize the techniques offered by this animal model to manipulate genes of interest, annotate gene expression, and describe the resulting phenotypes. We survey the sarcomere genes that have been investigated in zebrafish and discuss the potential of applying this in vivo model for larger-scale genetic studies.
Collapse
Affiliation(s)
- Jingchun Yang
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota; Division of Cardiovascular Diseases, Mayo Clinic College of Medicine, Rochester, Minnesota
| | | | | |
Collapse
|
22
|
Yang J, Hartjes KA, Nelson TJ, Xu X. Cessation of contraction induces cardiomyocyte remodeling during zebrafish cardiogenesis. Am J Physiol Heart Circ Physiol 2013; 306:H382-95. [PMID: 24322613 DOI: 10.1152/ajpheart.00721.2013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Contraction regulates heart development via a complex mechanotransduction process controlled by various mechanical forces. Here, we exploit zebrafish embryos as an in vivo animal model to discern the contribution from different mechanical forces and identify the underlying mechanotransductive signaling pathways of cardiogenesis. We treated 2 days postfertilization zebrafish embryos with Blebbistatin, a myosin II inhibitor, to stop cardiac contraction, which induces a response termed cessation of contraction-induced cardiomyocyte (CM) enlargement (CCE). Accompanying the CCE, lateral fusion of myofibrils was attenuated within CMs. The CCE can be blunted by loss of blood in tail-docked zebrafish but not in cloche mutant fish, suggesting that transmural pressure rather than shear stress is accountable for the chamber enlargement. By screening a panel of small molecule inhibitors, our data suggested essential functions of phosphoinositide 3-kinase signaling and protein synthesis in CCE, which are independent of the sarcomere integrity. In summary, we defined a unique CCE response in genetically tractable zebrafish embryos. A panel of assays was established to verify the contribution from extrinsic forces and interrogate underlying signaling pathways.
Collapse
Affiliation(s)
- Jingchun Yang
- Department of Biochemistry and Molecular Biology, Division of Cardiovascular Diseases, Mayo Clinic College of Medicine, Rochester, Minnesota
| | | | | | | |
Collapse
|
23
|
Novikov N, Evans T. Tmem88a mediates GATA-dependent specification of cardiomyocyte progenitors by restricting WNT signaling. Development 2013; 140:3787-98. [PMID: 23903195 DOI: 10.1242/dev.093567] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Biphasic control of WNT signaling is essential during cardiogenesis, but how the pathway switches from promoting cardiac mesoderm to restricting cardiomyocyte progenitor fate is unknown. We identified genes expressed in lateral mesoderm that are dysregulated in zebrafish when both gata5 and gata6 are depleted, causing a block to cardiomyocyte specification. This screen identified tmem88a, which is expressed in the early cardiac progenitor field and was previously implicated in WNT modulation by overexpression studies. Depletion of tmem88a results in a profound cardiomyopathy, secondary to impaired cardiomyocyte specification. In tmem88a morphants, activation of the WNT pathway exacerbates the cardiomyocyte deficiency, whereas WNT inhibition rescues progenitor cells and cardiogenesis. We conclude that specification of cardiac fate downstream of gata5/6 involves activation of the tmem88a gene to constrain WNT signaling and expand the number of cardiac progenitors. Tmem88a is a novel component of the regulatory mechanism controlling the second phase of biphasic WNT activity essential for embryonic cardiogenesis.
Collapse
Affiliation(s)
- Natasha Novikov
- Department of Surgery, Weill Cornell Medical College, Cornell University, 1300 York Ave., LC-708, New York, NY, USA
| | | |
Collapse
|
24
|
Rosenfeld GE, Mercer EJ, Mason CE, Evans T. Small heat shock proteins Hspb7 and Hspb12 regulate early steps of cardiac morphogenesis. Dev Biol 2013; 381:389-400. [PMID: 23850773 DOI: 10.1016/j.ydbio.2013.06.025] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 06/17/2013] [Accepted: 06/24/2013] [Indexed: 01/05/2023]
Abstract
Cardiac morphogenesis is a complex multi-stage process, and the molecular basis for controlling distinct steps remains poorly understood. Because gata4 encodes a key transcriptional regulator of morphogenesis, we profiled transcript changes in cardiomyocytes when Gata4 protein is depleted from developing zebrafish embryos. We discovered that gata4 regulates expression of two small heat shock genes, hspb7 and hspb12, both of which are expressed in the embryonic heart. We show that depletion of Hspb7 or Hspb12 disrupts normal cardiac morphogenesis, at least in part due to defects in ventricular size and shape. We confirmed that gata4 interacts genetically with the hspb7/12 pathway, but surprisingly, we found that hspb7 also has an earlier, gata4-independent function. Depletion perturbs Kupffer's vesicle (KV) morphology leading to a failure in establishing the left-right axis of asymmetry. Targeted depletion of Hspb7 in the yolk syncytial layer is sufficient to disrupt KV morphology and also causes an even earlier block to heart tube formation and a bifid phenotype. Recently, several genome-wide association studies found that HSPB7 SNPs are highly associated with idiopathic cardiomyopathies and heart failure. Therefore, GATA4 and HSPB7 may act alone or together to regulate morphogenesis with relevance to congenital and acquired human heart disease.
Collapse
|
25
|
Ding Y, Liu W, Deng Y, Jomok B, Yang J, Huang W, Clark KJ, Zhong TP, Lin X, Ekker SC, Xu X. Trapping cardiac recessive mutants via expression-based insertional mutagenesis screening. Circ Res 2013; 112:606-17. [PMID: 23283723 PMCID: PMC3603352 DOI: 10.1161/circresaha.112.300603] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
RATIONALE Mutagenesis screening is a powerful genetic tool for probing biological mechanisms underlying vertebrate development and human diseases. However, the increased colony management efforts in vertebrates impose a significant challenge for identifying genes affecting a particular organ, such as the heart, especially those exhibiting adult phenotypes on depletion. OBJECTIVE We aim to develop a facile approach that streamlines colony management efforts via enriching cardiac mutants, which enables us to screen for adult phenotypes. METHODS AND RESULTS The transparency of the zebrafish embryos enabled us to score 67 stable transgenic lines generated from an insertional mutagenesis screen using a transposon-based protein trapping vector. Fifteen lines with cardiac monomeric red fluorescent protein reporter expression were identified. We defined the molecular nature for 10 lines and bred them to homozygosity, which led to the identification of 1 embryonic lethal, 1 larval lethal, and 1 adult recessive mutant exhibiting cardiac hypertrophy at 1 year of age. Further characterization of these mutants uncovered an essential function of methionine adenosyltransferase II, α a (mat2aa) in cardiogenesis, an essential function of mitochondrial ribosomal protein S18B (mrps18b) in cardiac mitochondrial homeostasis, as well as a function of DnaJ (Hsp40) homolog, subfamily B, member 6b (dnajb6b) in adult cardiac hypertrophy. CONCLUSIONS We demonstrate that transposon-based gene trapping is an efficient approach for identifying both embryonic and adult recessive mutants with cardiac expression. The generation of a zebrafish insertional cardiac mutant collection shall facilitate the annotation of a vertebrate cardiac genome, as well as enable heart-based adult screens.
Collapse
Affiliation(s)
- Yonghe Ding
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905
- Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905
- Department of Genetics and Development Biology, College of Life Sciences, Hunan Normal University, P.R. China
| | - Weibin Liu
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905
- Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Yun Deng
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905
- Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Beninio Jomok
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905
- Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Jingchun Yang
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905
- Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Wei Huang
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905
- Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905
- Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Karl J. Clark
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Tao P. Zhong
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, P.R. China
| | - Xueying Lin
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905
- Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Stephen C. Ekker
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Xiaolei Xu
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905
- Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN 55905
| |
Collapse
|
26
|
Yang J, Xu X. α-Actinin2 is required for the lateral alignment of Z discs and ventricular chamber enlargement during zebrafish cardiogenesis. FASEB J 2012; 26:4230-42. [PMID: 22767232 DOI: 10.1096/fj.12-207969] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
α-Actinin2 (Actn2) is a predominant protein in the sarcomere Z disc whose mutation can lead to cardiomyopathy. However, the function of Actn2 in Z-disc assembly and cardiomyopathy in vertebrates remains elusive. We leveraged genetic tools in zebrafish embryos to elucidate the function of Actn2. We identified a single Actn2 homologue expressed in the zebrafish heart and conducted loss-of-function studies by antisense morpholino technology. Although zebrafish Actn2 assembles early into the Z disc, depletion of actn2 did not affect the early steps of sarcomere assembly. Instead, Actn2 is required for Z bodies to register laterally, forming well-aligned Z discs. Presumably as a consequence to this structural defect in the sarcomere, the depletion of Actn2 resulted in reduced cardiac function, primarily characterized as a reduced end-diastolic diameter. The depletion of actn2 also significantly reduced the ventricle chamber size, due to both reduced cardiomyocyte (CM) size and CM number. Interestingly, reduced CM size can be rescued by the cessation of heart contractions. The genetic studies of zebrafish uncovered a function for actn2 in lateral registration of Z body. In actn2 morphant fish, the Z-disc defect sequentially affects cardiac function, which leads to morphological changes in the ventricle through a mechanical force-dependent mechanism.
Collapse
Affiliation(s)
- Jingchun Yang
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, 200 First St. SW, Rochester, MN 55905, USA
| | | |
Collapse
|