scholarly journals Loss of function of Kmt2d, a gene mutated in Kabuki syndrome, affects heart development inXenopus laevis

2019 ◽  
Vol 248 (6) ◽  
pp. 465-476 ◽  
Author(s):  
Janina Schwenty‐Lara ◽  
Annika Nürnberger ◽  
Annette Borchers
Keyword(s):  
Heart Development ◽  
Kabuki Syndrome ◽  
Loss Of Function ◽  
Inxenopus Laevis

scholarly journals Exposure to Mites Sensitizes Intestinal Stem Cell Maintenance, Splenic Marginal Zone B Cell Homeostasis, And Heart Development to Notch Dosage and Cooperativity

2020 ◽  
Author(s):  
Francis M. Kobia ◽  
Kristina Preusse ◽  
Quanhui Dai ◽  
Nicholas Weaver ◽  
Praneet Chaturvedi ◽  
...  
Keyword(s):  
B Cell ◽  
Heart Development ◽  
Marginal Zone ◽  
B Cell Lymphoma ◽  
Mite Infestation ◽  
List Type ◽  
Loss Of Function ◽  
B Cell Homeostasis

AbstractCooperative DNA binding is a key feature of transcriptional regulation. Here we examined the role of cooperativity in Notch signaling by CRISPR-mediated engineering of mice in which neither Notch1 nor Notch2 can homo- or heterodimerize, essential for cooperative binding to sequence paired sites (SPS) located near many Notch-regulated genes. While most known Notch-dependent phenotypes were unaffected in Notch1/2 dimer-deficient mice, a subset of tissues proved highly sensitive to loss of cooperativity. These phenotypes include heart development, compromising viability in combination with low gene dose, and the gut, developing ulcerative colitis in response to 1% DSS. The most striking phenotypes – gender imbalance and splenic marginal zone B cell lymphoma – emerged in combination with dose reduction or when challenged by chronic fur mite infestation. This study highlights the role of the environment in malignancy and colitis, and is consistent with Notch-dependent anti-parasite immune responses being compromised in the dimer deficient animals.HighlightsNotch dimerization has an in vivo role in contributing to intestinal homeostasisLoss of cooperativity can manifest as Notch gain or loss of function phenotypesMite infestation exacerbates all phenotypes, triggers MZB hyperproliferation in mutant animalsMite-infested mutant mice develop SMZL with age

scholarly journals The role of KMT2D and KDM6A in cardiac development: A cross-species analysis in humans, mice, and zebrafish

2020 ◽  
Author(s):  
Rwik Sen ◽  
Ezra Lencer ◽  
Elizabeth A. Geiger ◽  
Kenneth L. Jones ◽  
Tamim H. Shaikh ◽  
...  
Keyword(s):  
Gene Expression ◽  
Heart Development ◽  
Target Genes ◽  
Cardiac Development ◽  
Heart Defects ◽  
Neural Crest Cell ◽  
Kabuki Syndrome ◽  
Rna Seq ◽  
Wide Range

AbstractCongenital Heart Defects (CHDs) are the most common form of birth defects, observed in 4-10/1000 live births. CHDs result in a wide range of structural and functional abnormalities of the heart which significantly affect quality of life and mortality. CHDs are often seen in patients with mutations in epigenetic regulators of gene expression, like the genes implicated in Kabuki syndrome – KMT2D and KDM6A, which play important roles in normal heart development and function. Here, we examined the role of two epigenetic histone modifying enzymes, KMT2D and KDM6A, in the expression of genes associated with early heart and neural crest cell (NCC) development. Using CRISPR/Cas9 mediated mutagenesis of kmt2d, kdm6a and kdm6al in zebrafish, we show cardiac and NCC gene expression is reduced, which correspond to affected cardiac morphology and reduced heart rates. To translate our results to a human pathophysiological context and compare transcriptomic targets of KMT2D and KDM6A across species, we performed RNA sequencing (seq) of lymphoblastoid cells from Kabuki Syndrome patients carrying mutations in KMT2D and KDM6A. We compared the human RNA-seq datasets with RNA-seq datasets obtained from mouse and zebrafish. Our comparative interspecies analysis revealed common targets of KMT2D and KDM6A, which are shared between species, and these target genes are reduced in expression in the zebrafish mutants. Taken together, our results show that KMT2D and KDM6A regulate common and unique genes across humans, mice, and zebrafish for early cardiac and overall development that can contribute to the understanding of epigenetic dysregulation in CHDs.

scholarly journals Dynamics of Cardiomyocyte Transcriptome and Chromatin Landscape Demarcates Key Events of Heart Development

2018 ◽  
Author(s):  
Michal Pawlak ◽  
Katarzyna Z. Kedzierska ◽  
Maciej Migdal ◽  
Karim Abu Nahia ◽  
Jordan A. Ramilowski ◽  
...  
Keyword(s):  
Heart Development ◽  
Regulatory Networks ◽  
Regulatory Elements ◽  
Chromatin Accessibility ◽  
Proximal Promoter ◽  
Global Changes ◽  
Open Chromatin ◽  
Sequence Motifs ◽  
Loss Of Function ◽  
Heart Looping

ABSTRACTThe development of an organ involves dynamic regulation of gene transcription and complex multipathway interactions. To better understand transcriptional regulatory mechanism driving heart development and the consequences of its disruption, we isolated cardiomyocytes (CMs) from wild-type zebrafish embryos at 24, 48 and 72 hours post fertilization corresponding to heart looping, chamber formation and heart maturation, and from mutant lines carrying loss-of-function mutations in gata5, tbx5a and hand2, transcription factors (TFs) required for proper heart development. The integration of CM transcriptomics (RNA-seq) and genome-wide chromatin accessibility maps (ATAC-seq) unravelled dynamic regulatory networks driving crucial events of heart development. These networks contained key cardiac TFs including Gata5/6, Nkx2.5, Tbx5/20, and Hand2, and are associated with open chromatin regions enriched for DNA sequence motifs belonging to the family of the corresponding TFs. These networks were disrupted in cardiac TF mutants, indicating their importance in proper heart development. The most prominent gene expression changes, which correlated with chromatin accessibility modifications within their proximal promoter regions, occurred between heart looping and chamber formation, and were associated with metabolic and hematopoietic/cardiac switch during CM maturation. Furthermore, loss of function of cardiac TFs Gata5, Tbx5a, and Hand2 affected the cardiac regulatory networks and caused global changes in chromatin accessibility profile. Among regions with differential chromatin accessibility in mutants were highly conserved non-coding elements which represent putative cis regulatory elements with potential role in heart development and disease. Altogether, our results revealed the dynamic regulatory landscape at key stages of heart development and identified molecular drivers of heart morphogenesis.

scholarly journals miR-128a Acts as a Regulator in Cardiac Development by Modulating Differentiation of Cardiac Progenitor Cell Populations

2020 ◽  
Vol 21 (3) ◽  
pp. 1158 ◽  
Author(s):  
Sarah C. Hoelscher ◽  
Theresia Stich ◽  
Anne Diehm ◽  
Harald Lahm ◽  
Martina Dreßen ◽  
...  
Keyword(s):  
Pluripotent Stem Cells ◽  
Heart Development ◽  
Regulatory Networks ◽  
Progenitor Cell ◽  
Cardiac Development ◽  
Loss Of Function ◽  
And Function ◽  
Cardiac Transcription Factors ◽  
Beating Frequency

MicroRNAs (miRs) appear to be major, yet poorly understood players in regulatory networks guiding cardiogenesis. We sought to identify miRs with unknown functions during cardiogenesis analyzing the miR-profile of multipotent Nkx2.5 enhancer cardiac progenitor cells (NkxCE-CPCs). Besides well-known candidates such as miR-1, we found about 40 miRs that were highly enriched in NkxCE-CPCs, four of which were chosen for further analysis. Knockdown in zebrafish revealed that only miR-128a affected cardiac development and function robustly. For a detailed analysis, loss-of-function and gain-of-function experiments were performed during in vitro differentiations of transgenic murine pluripotent stem cells. MiR-128a knockdown (1) increased Isl1, Sfrp5, and Hcn4 (cardiac transcription factors) but reduced Irx4 at the onset of cardiogenesis, (2) upregulated Isl1-positive CPCs, whereas NkxCE-positive CPCs were downregulated, and (3) increased the expression of the ventricular cardiomyocyte marker Myl2 accompanied by a reduced beating frequency of early cardiomyocytes. Overexpression of miR-128a (4) diminished the expression of Isl1, Sfrp5, Nkx2.5, and Mef2c, but increased Irx4, (5) enhanced NkxCE-positive CPCs, and (6) favored nodal-like cardiomyocytes (Tnnt2+, Myh6+, Shox2+) accompanied by increased beating frequencies. In summary, we demonstrated that miR-128a plays a so-far unknown role in early heart development by affecting the timing of CPC differentiation into various cardiomyocyte subtypes.

scholarly journals Histone H2B monoubiquitination regulates heart development via epigenetic control of cilia motility

2019 ◽  
Vol 116 (28) ◽  
pp. 14049-14054 ◽  
Author(s):  
Andrew Robson ◽  
Svetlana Z. Makova ◽  
Syndi Barish ◽  
Samir Zaidi ◽  
Sameet Mehta ◽  
...  
Keyword(s):  
Chromatin Remodeling ◽  
Heart Development ◽  
Loss Of Function ◽  
Developmentally Regulated ◽  
Specific Expression ◽  
Histone H2b ◽  
Tissue Specific ◽  
Heart Looping ◽  
Significant Enrichment ◽  
Gene Ontologies

Genomic analyses of patients with congenital heart disease (CHD) have identified significant contribution from mutations affecting cilia genes and chromatin remodeling genes; however, the mechanism(s) connecting chromatin remodeling to CHD is unknown. Histone H2B monoubiquitination (H2Bub1) is catalyzed by the RNF20 complex consisting of RNF20, RNF40, and UBE2B. Here, we show significant enrichment of loss-of-function mutations affecting H2Bub1 in CHD patients (enrichment 6.01,P= 1.67 × 10−03), some of whom had abnormal laterality associated with ciliary dysfunction. InXenopus, knockdown ofrnf20andrnf40results in abnormal heart looping, defective development of left–right (LR) asymmetry, and impaired cilia motility. Rnf20, Rnf40, and Ube2b affect LR patterning and cilia synergistically. Examination of global H2Bub1 level inXenopusembryos shows that H2Bub1 is developmentally regulated and requires Rnf20. To examine gene-specific H2Bub1, we performed ChIP-seq of mouse ciliated and nonciliated tissues and showed tissue-specific H2Bub1 marks significantly enriched at cilia genes including the transcription factorRfx3. Rnf20 knockdown results in decreased levels ofrfx3mRNA inXenopus, and exogenousrfx3can rescue the Rnf20 depletion phenotype. These data suggest that Rnf20 functions at theRfx3locus regulating cilia motility and cardiac situs and identify H2Bub1 as an upstream transcriptional regulator controlling tissue-specific expression of cilia genes. Our findings mechanistically link the two functional gene ontologies that have been implicated in human CHD: chromatin remodeling and cilia function.

scholarly journals Rare mutations of ADAM17 from TOFs induce hypertrophy in human embryonic stem cell-derived cardiomyocytes via HB-EGF signaling

2019 ◽  
Vol 133 (2) ◽  
pp. 225-238 ◽  
Author(s):  
Yifang Xie ◽  
Anyun Ma ◽  
Boshi Wang ◽  
Rui Peng ◽  
Yingchun Jing ◽  
...  
Keyword(s):  
Growth Factor ◽  
Heart Development ◽  
Heart Defects ◽  
Embryonic Stem ◽  
Growth Factor Receptor ◽  
Heparin Binding ◽  
Loss Of Function ◽  
Knock Out ◽  
Critical Pathways

Abstract Tetralogy of Fallot (TOF) is the most common cyanotic form of congenital heart defects (CHDs). The right ventricular hypertrophy is associated with the survival rate of patients with repaired TOF. However, very little is known concerning its genetic etiology. Based on mouse model studies, a disintergrin and metalloprotease 10/17 (ADAM10 and ADAM17) are the key enzymes for the NOTCH and ErbB pathways, which are critical pathways for heart development. Mutations in these two genes have not been previously reported in human TOF patients. In this study, we sequenced ADAM10 and ADAM17 in a Han Chinese CHD cohort comprised of 80 TOF patients, 286 other CHD patients, and 480 matched healthy controls. Three missense variants of ADAM17 were only identified in 80 TOF patients, two of which (Y42D and L659P) are novel and not found in the Exome Aggregation Consortium (ExAC) database. Point mutation knock-in (KI) and ADAM17 knock-out (KO) human embryonic stem cells (hESCs) were generated by CRISPR/Cas9 and programmed to differentiate into cardiomyocytes (CMs). Y42D or L659P KI cells or complete KO cells all developed hypertrophy with disorganized sarcomeres. RNA-seq results showed that phosphatidylinositide 3-kinases/protein kinase B (PI3K/Akt), which is downstream of epidermal growth factor receptor (EGFR) signaling, was affected in both ADAM17 KO and KI hESC-CMs. In vitro experiments showed that these two mutations are loss-of-function mutations in shedding heparin-binding EGF-like growth factor (HB-EGF) but not NOTCH signaling. Our results revealed that CM hypertrophy in TOF could be the result of mutations in ADAM17 which affects HB-EGF/ErbB signaling.

scholarly journals Nkx2.5 is essential to establish normal heart rate variability in the zebrafish embryo

2017 ◽  
Vol 313 (3) ◽  
pp. R265-R271 ◽  
Author(s):  
Jamie K. Harrington ◽  
Robert Sorabella ◽  
Abigail Tercek ◽  
Joseph R. Isler ◽  
Kimara L. Targoff
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Heart Development ◽  
Conduction System ◽  
Cardiac Conduction ◽  
Loss Of Function ◽  
Normal Heart ◽  
Wild Type ◽  
Cardiac Health ◽  
Normal Heart Rate

Heart rate variability (HRV) has become an important clinical marker of cardiovascular health and a research measure for the study of the cardiac conduction system and its autonomic controls. While the zebrafish ( Danio rerio) is an ideal vertebrate model for understanding heart development, HRV has only recently been investigated in this system. We have previously demonstrated that nkx2.5 and nkx2.7, two homologues of Nkx2–5 expressed in zebrafish cardiomyocytes, play vital roles in maintaining cardiac chamber-specific characteristics. Given observed defects in ventricular and atrial chamber identities in nkx2.5−/− embryos coupled with conduction system abnormalities in murine models of Nkx2.5 insufficiency, we postulated that reduced HRV would serve as a marker of poor cardiac health in nkx2.5 mutants and in other zebrafish models of human congenital heart disease. Using live video image acquisition, we derived beat-to-beat intervals to compare HRV in wild-type and nkx2.5−/− embryos. Our data illustrate that the nkx2.5 loss-of-function model exhibits increased heart rate and decreased HRV when compared with wild type during embryogenesis. These findings validate HRV analysis as a useful quantitative tool for assessment of cardiac health in zebrafish and underscore the importance of nkx2.5 in maintaining normal heart rate and HRV during early conduction system development.

scholarly journals Activation of amino acid metabolic program in response to impaired glycolysis in cardiac HIF1 deficient mice

2020 ◽  
Author(s):  
Ivan Menendez-Montes ◽  
Beatriz Escobar ◽  
Manuel J. Gomez ◽  
Teresa Albendea-Gomez ◽  
Beatriz Palacios ◽  
...  
Keyword(s):  
Amino Acid ◽  
Heart Development ◽  
Alternative Energy ◽  
Therapeutic Interventions ◽  
Acid Oxidation ◽  
Normal Fatty Acid ◽  
Loss Of Function ◽  
Cardiac Progenitors ◽  
Knock Out ◽  
The Impact

ABSTRACTHypoxia is an important environmental cue in heart development. Despite of extensive characterization of gain and loss of function models, there is disagreement about the impact of HIF1α elimination in cardiac tissue. Here, we used a new conditional knock out of Hif1a in NKX2.5 cardiac progenitors to assess the morphological and functional consequences of HIF1α loss in the developing heart. By combining histology, electron microscopy and high-throughout genomics, proteomics and metabolomics, we found that deletion of Hif1a leads to impaired embryonic glycolysis without influencing cardiomyocyte proliferation and results in an increased mitochondrial number, activation of a transient amino acid response and upregulation of HIF2α and ATF4 by E12.5. Hif1a mutants display normal fatty acid oxidation metabolic profile and do not show any sign of cardiac dysfunction in the adulthood. Our results demonstrate that HIF1 signaling is dispensable for heart development and reveal the metabolic flexibility of the embryonic myocardium, opening the potential application of alternative energy sources as therapeutic interventions during ischemic events.

scholarly journals Repulsion by Slit and Roundabout prevents Shotgun/E-cadherin–mediated cell adhesion during Drosophila heart tube lumen formation

2008 ◽  
Vol 182 (2) ◽  
pp. 241-248 ◽  
Author(s):  
Edgardo Santiago-Martínez ◽  
Nadine H. Soplop ◽  
Rajesh Patel ◽  
Sunita G. Kramer
Keyword(s):  
Cell Adhesion ◽  
Heart Development ◽  
Cell Junction ◽  
Loss Of Function ◽  
Heart Tube ◽  
Gain Of Function ◽  
Lumen Formation ◽  
Tube Lumen ◽  
Function Blocks ◽  
E Cadherin

During Drosophila melanogaster heart development, a lumen forms between apical surfaces of contralateral cardioblasts (CBs). We show that Slit and its receptor Roundabout (Robo) are required at CB apical domains for lumen formation. Mislocalization of Slit outside the apical domain causes ectopic lumen formation and the mislocalization of cell junction proteins, E-cadherin (E-Cad) and Enabled, without disrupting overall CB cell polarity. Ectopic lumen formation is suppressed in robo mutants, which indicates robo's requirement for this process. Genetic evidence suggests that Robo and Shotgun (Shg)/E-Cad function together in modulating CB adhesion. robo and shg/E-Cad transheterozygotes have lumen defects. In robo loss-of-function or shg/E-Cad gain-of-function embryos, lumen formation is blocked because of inappropriate CB adhesion and an accumulation of E-Cad at the apical membrane. In contrast, shg/E-Cad loss-of-function or robo gain-of-function blocks lumen formation due to a loss of CB adhesion. Our data show that Slit and Robo pathways function in lumen formation as a repulsive signal to antagonize E-Cad–mediated cell adhesion.

Neuron Navigator 3 (NAV3) is Required for Heart Development in Zebrafish

2021 ◽  
Author(s):  
Feng Lv ◽  
Xiaojuan Ge ◽  
Peipei Qian ◽  
Xiaofeng Lu ◽  
Dong Liu ◽  
...  
Keyword(s):  
Heart Development ◽  
Three Dimensional ◽  
Cell Types ◽  
Zebrafish Embryos ◽  
Loss Of Function ◽  
Cardiac Region ◽  
Severe Deficiency ◽  
Three Dimensional Configuration ◽  
And Migration ◽  
Guidance Molecule

Abstract As a tightly controlled biological process, cardiogenesis requires the specification and migration of a suite of cell types to form a particular three-dimensional configuration of the heart. Many genetic factors are involved in the formation and maturation of the heart, and any genetic mutations may result in severe cardiac failures. The neuron navigator (NAV) family consists of three vertebrate homologs (NAV1, NAV2, and NAV3) of the neural guidance molecule Uncoordinated-53 (UNC-53) in Caenorhabditis elegans. Although they are recognized as neural regulators, their expressions are also detected in many organs, including the heart, kidney, and liver. However, the functions of NAVs, regardless of neural guidance, remain largely unexplored. In our study, we found that nav3 gene was expressed in the cardiac region of zebrafish embryos from 24 to 48 hours post-fertilization (hpf) by means of in situ hybridization (ISH) assay. A CRISPR/Cas9-based genome editing method was utilized to delete the nav3 gene in zebrafish and loss-of-function of Nav3 resulted in a severe deficiency in its cardiac morphology and structure. The similar phenotypic defects of the knockout mutants could recur by nav3 morpholino injection and be rescued by nav3 mRNA injection. Dual-color fluorescence imaging of ventricle and atrium markers further confirmed the disruption of the heart development in nav3-deleted mutants. Although the heart rate was not affected by the deletion of nav3, the heartbeat intensity was decreased in the mutants. All these findings indicate that Nav3 was required for cardiogenesis in developing zebrafish embryos.

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