Igf Signaling is Required for Cardiomyocyte Proliferation during Zebrafish Heart Development and Regeneration

Introduction: Mammalian heart possesses regenerative potential immediately after birth and lost by one week of age. The mechanisms that govern neonatal cardiomyocyte proliferation and regenerative capacity are poorly understood. Recent reports indicate that Yap-Tead transcriptional complex is necessary and sufficient for cardiomyocyte proliferation. During postnatal development, N-cadherin/catenin adhesion complex becomes concentrated at termini of cardiomyocytes facilitating maturation of a specialized intercellular junction structure, the intercalated disc (ICD). This process coincides with the time cardiomyocytes exit cell cycle soon after birth. Hypothesis: We hypothesize that coincident with maturation of ICD α-catenins sequester transcriptional coactivator Yap in cytosol thus preventing activation of genes critical for cardiomyocyte proliferation. Methods: We deleted αE-catenin / αT-catenin genes (α-cat DKO) in perinatal mouse heart and knockdown (KD) α-catenins in neonatal rat cardiomyocytes to study functional impact of α-catenins ablation on ICD maturation. Results: We previously demonstrated that adult α-cat DKO mice exhibited decrease in scar size and improved function post myocardial infarction. In present study, we investigated function of α-catenins during postnatal heart development. We found increase in the number of Yap-positive nuclei (58.7% in DKO vs. 35.8 % in WT, n=13, p<0.001) and PCNA (53.9% in DKO vs. 47.8%, n=8, p<0.05) at postnatal day 1 and day 7 of α-cat DKO heart, respectively. Loss of α-catenins resulted in reduction in N-cadherin at ICD at day 14. We observed an increase number of mononucleated myocytes and decrease number of binucleated myocytes in α-cat DKO compared to controls. Using siRNA KD, we were able to replicate α-cat DKO proliferative phenotype in vitro. The number of BrdU-positive cells was decreased in α-cat KD after interfering with Yap expression (2.91% in α-cat KD vs. 2.02% in α-cat/Yap KD, n>2500 cells, p<0.05), suggesting α-catenins regulate cell proliferation through Yap in neonatal cardiomyocytes. Conclusion: Our results suggest that maturation of ICD regulates α-catenin-Yap interactions in cytosol, thus preventing Yap nuclear accumulation and cardiomyocyte proliferation.

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Lamb1a regulates atrial growth by limiting excessive, contractility-dependent second heart field addition during zebrafish heart development

10.1101/2021.03.10.434727 ◽

2021 ◽

Author(s):

Christopher J. Derrick ◽

Eric J. G. Pollitt ◽

Ashley Sanchez Sevilla Uruchurtu ◽

Farah Hussein ◽

Emily S. Noёl

Keyword(s):

Heart Development ◽

Cardiac Development ◽

Basement Membranes ◽

Atrioventricular Canal ◽

Cardiac Morphogenesis ◽

Heart Morphogenesis ◽

Second Heart Field ◽

Heart Field ◽

Heart Size ◽

Zebrafish Heart

AbstractDuring early vertebrate heart development, the heart transitions from a linear tube to a complex asymmetric structure. This process includes looping of the tube and ballooning of the emerging cardiac chambers, which occur simultaneously with growth of the heart. A key driver of cardiac growth is deployment of cells from the Second Heart Field (SHF) into both poles of the heart, with cardiac morphogenesis and growth intimately linked in heart development. Laminin is a core component of extracellular matrix (ECM) basement membranes, and although mutations in specific laminin subunits are linked with a variety of cardiac abnormalities, including congenital heart disease and dilated cardiomyopathy, no role for laminin has been identified in early vertebrate heart morphogenesis. We identified dynamic, tissue-specific expression of laminin subunit genes in the developing zebrafish heart, supporting a role for laminins in heart morphogenesis.lamb1amutants exhibit cardiomegaly from 2dpf onwards, with subsequent progressive defects in cardiac morphogenesis characterised by a failure of the chambers to compact around the developing atrioventricular canal. We show that loss oflamb1aresults in excess addition of SHF cells to the atrium, revealing that Lamb1a functions to limit heart size during cardiac development by restricting SHF addition to the venous pole.lamb1amutants exhibit hallmarks of altered haemodynamics, and specifically blocking cardiac contractility inlamb1amutants rescues heart size and atrial SHF addition. Furthermore, we identify that FGF and RA signalling, two conserved pathways promoting SHF addition, are regulated by heart contractility and are dysregulated inlamb1amutants, suggesting that laminin mediates interactions between SHF deployment, heart biomechanics, and biochemical signalling during heart development. Together, this describes the first requirement for laminins in early vertebrate heart morphogenesis, reinforcing the importance of specialised ECM composition in cardiac development.

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Intercalated disc protein Xinβ is required for Hippo-YAP signaling in the heart

Nature Communications ◽

10.1038/s41467-020-18379-8 ◽

2020 ◽

Vol 11 (1) ◽

Author(s):

Haipeng Guo ◽

Yao Wei Lu ◽

Zhiqiang Lin ◽

Zhan-Peng Huang ◽

Jianming Liu ◽

...

Keyword(s):

Cardiovascular Diseases ◽

Cardiac Function ◽

Heart Development ◽

Genetic Interaction ◽

Specific Cell ◽

Cardiomyocyte Proliferation ◽

Intercalated Disc ◽

Knock Out ◽

Genes Encoding ◽

Knock Out Mice

Abstract Intercalated discs (ICD), specific cell-to-cell contacts that connect adjacent cardiomyocytes, ensure mechanical and electrochemical coupling during contraction of the heart. Mutations in genes encoding ICD components are linked to cardiovascular diseases. Here, we show that loss of Xinβ, a newly-identified component of ICDs, results in cardiomyocyte proliferation defects and cardiomyopathy. We uncovered a role for Xinβ in signaling via the Hippo-YAP pathway by recruiting NF2 to the ICD to modulate cardiac function. In Xinβ mutant hearts levels of phosphorylated NF2 are substantially reduced, suggesting an impairment of Hippo-YAP signaling. Cardiac-specific overexpression of YAP rescues cardiac defects in Xinβ knock-out mice—indicating a functional and genetic interaction between Xinβ and YAP. Our study reveals a molecular mechanism by which cardiac-expressed intercalated disc protein Xinβ modulates Hippo-YAP signaling to control heart development and cardiac function in a tissue specific manner. Consequently, this pathway may represent a therapeutic target for the treatment of cardiovascular diseases.

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Cardiomyocyte proliferation in cardiac development and regeneration: a guide to methodologies and interpretations

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00559.2015 ◽

2015 ◽

Vol 309 (8) ◽

pp. H1237-H1250 ◽

Cited By ~ 59

Author(s):

Marina Leone ◽

Ajit Magadum ◽

Felix B. Engel

Keyword(s):

Cardiac Function ◽

Molecular Mechanisms ◽

Cardiac Development ◽

Cardiac Regeneration ◽

Experimental Medicine ◽

Heart Regeneration ◽

Cardiomyocyte Proliferation ◽

Naturally Occurring ◽

Ability To Regenerate ◽

Zebrafish Heart

The newt and the zebrafish have the ability to regenerate many of their tissues and organs including the heart. Thus, a major goal in experimental medicine is to elucidate the molecular mechanisms underlying the regenerative capacity of these species. A wide variety of experiments have demonstrated that naturally occurring heart regeneration relies on cardiomyocyte proliferation. Thus, major efforts have been invested to induce proliferation of mammalian cardiomyocytes in order to improve cardiac function after injury or to protect the heart from further functional deterioration. In this review, we describe and analyze methods currently used to evaluate cardiomyocyte proliferation. In addition, we summarize the literature on naturally occurring heart regeneration. Our analysis highlights that newt and zebrafish heart regeneration relies on factors that are also utilized in cardiomyocyte proliferation during mammalian fetal development. Most of these factors have, however, failed to induce adult mammalian cardiomyocyte proliferation. Finally, our analysis of mammalian neonatal heart regeneration indicates experiments that could resolve conflicting results in the literature, such as binucleation assays and clonal analysis. Collectively, cardiac regeneration based on cardiomyocyte proliferation is a promising approach for improving adult human cardiac function after injury, but it is important to elucidate the mechanisms arresting mammalian cardiomyocyte proliferation after birth and to utilize better assays to determine formation of new muscle mass.

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The zebrafish as a model for cardiac development and regeneration

10.1093/med/9780198757269.003.0029 ◽

2018 ◽

Cited By ~ 1

Author(s):

Bill Chaudhry ◽

José Luis de la Pompa ◽

Nadia Mercader

Keyword(s):

Heart Development ◽

Cardiac Development ◽

Model Organism ◽

Laboratory Model ◽

Developmental Studies ◽

Sequencing Technologies ◽

Technological Advances ◽

The Common ◽

Zebrafish Heart

The zebrafish has become an established laboratory model for developmental studies and is increasingly used to model aspects of human development and disease. However, reviewers and grant funding bodies continue to speculate on the utility of this Himalayan minnow. In this chapter we explain the similarities and differences between the heart from this distantly related vertebrate and the mammalian heart, in order to reveal the common fundamental processes and to prevent misleading extrapolations. We provide an overview of zebrafish including their husbandry, development, peculiarities of their genome, and technological advances, which make them a highly tractable laboratory model for heart development and disease. We discuss the controversies around morphants and mutants, and relate the development and structures of the zebrafish heart to mammalian counterparts. Finally, we give an overview of regeneration in the zebrafish heart and speculate on the role of the model organism in next-generation sequencing technologies.

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Delineating the Dynamic Transcriptome Response of mRNA and microRNA during Zebrafish Heart Regeneration

Biomolecules ◽

10.3390/biom9010011 ◽

2018 ◽

Vol 9 (1) ◽

pp. 11 ◽

Cited By ~ 3

Author(s):

Hagen Klett ◽

Lonny Jürgensen ◽

Patrick Most ◽

Martin Busch ◽

Fabian Günther ◽

...

Keyword(s):

Heart Function ◽

Heart Diseases ◽

Expression Profiles ◽

Temporal Organization ◽

H9c2 Cell ◽

Specific Response ◽

Heart Regeneration ◽

Cardiomyocyte Proliferation ◽

Transcriptome Response ◽

Zebrafish Heart

Heart diseases are the leading cause of death for the vast majority of people around the world, which is often due to the limited capability of human cardiac regeneration. In contrast, zebrafish have the capacity to fully regenerate their hearts after cardiac injury. Understanding and activating these mechanisms would improve health in patients suffering from long-term consequences of ischemia. Therefore, we monitored the dynamic transcriptome response of both mRNA and microRNA in zebrafish at 1–160 days post cryoinjury (dpi). Using a control model of sham-operated and healthy fish, we extracted the regeneration specific response and further delineated the spatio-temporal organization of regeneration processes such as cell cycle and heart function. In addition, we identified novel (miR-148/152, miR-218b and miR-19) and previously known microRNAs among the top regulators of heart regeneration by using theoretically predicted target sites and correlation of expression profiles from both mRNA and microRNA. In a cross-species effort, we validated our findings in the dynamic process of rat myoblasts differentiating into cardiomyocytes-like cells (H9c2 cell line). Concluding, we elucidated different phases of transcriptomic responses during zebrafish heart regeneration. Furthermore, microRNAs showed to be important regulators in cardiomyocyte proliferation over time.

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Lmp4 regulates Tbx5 during zebrafish heart development

Developmental Biology ◽

10.1016/j.ydbio.2006.04.418 ◽

2006 ◽

Vol 295 (1) ◽

pp. 460-461 ◽

Cited By ~ 1

Author(s):

Troy Camarata ◽

Jacek Topczewski ◽

Hans-Georg Simon

Keyword(s):

Heart Development ◽

Zebrafish Heart

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