Abstract MP245: Tet Proteins Regulate Second Heart Field Multipotent Progenitors Differentiating To Myocytes

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Shaohai Fang ◽  
Jia Li ◽  
Jeff D Steimle ◽  
Lei Guo ◽  
Yuhan Yang ◽  
...  

DNA methylation and demethylation play an important role in shaping the epigenetic landscape and chromatin accessibility to control gene expression during development in mammals. Ten-eleven Translocation (Tet1, Tet2 and Tet3) is a family of dioxygenases that catalyze DNA methylation oxidation with ultimate DNA demethylation. Our previous study showed that cardiac-specific deletion of Tet2 and Tet3 could disrupt YY1-mediated long range chromatin interactions during heart development and lead to ventricular non-compaction cardiomyopathy. However, it is still unclear whether and how Tet protein mediated epigenetic modifications contribute to cardiac lineage specification during embryonic development. In this study, we generated cardiac specific Tet1-3 triple deficient (Tet-TKO) mouse lines using various cardiac specific Cres to evaluate the function of Tet protein in regulating cardiac lineage specification. We observed developmental defects at outflow tract (OFT) in Tet-TKO embryos, suggesting that Tet deficiency affects the second heart field (SHF) development. Single cell RNA-seq analysis further revealed the accumulation of multipotent SHF progenitors and subsequent halt of myocyte differentiation upon Tet depletion. At the molecular level, we found that Tet ablation perturbs the transcriptional network of Islet1, a transcription factor that is crucial for cardiac development in embryos. Overall, our study demonstrates a critical role of Tet-mediated epigenetic regulation for embryonic cardiac development.

2021 ◽  
Author(s):  
Christopher J. Derrick ◽  
Eric J. G. Pollitt ◽  
Ashley Sanchez Sevilla Uruchurtu ◽  
Farah Hussein ◽  
Emily S. Noёl

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.


2019 ◽  
Author(s):  
Michael J Reimer ◽  
Kirthi Pulakanti ◽  
Linzheng Shi ◽  
Alex Abel ◽  
Mingyu Liang ◽  
...  

Abstract Background: The Tet protein family (Tet1, Tet2, and Tet3) regulate DNA methylation through conversion of 5-methylcytosine to 5-hydroxymethylcytosine which can ultimately result in DNA demethylation and play a critical role during early mammalian development and pluripotency¬. While multiple groups have generated knockouts combining loss of different Tet proteins in murine embryonic stem cells (ESCs), differences in genetic background and approaches has made it difficult to directly compare results and discern the direct mechanism by which Tet proteins regulate the transcriptome. To address this concern, we utilized genomic editing in an isogenic pluripotent background which permitted a quantitative, flow-cytometry based measurement of pluripotency in combination with genome-wide assessment of gene expression and DNA methylation changes. Our ultimate goal was to generate a resource of large-scale datasets to permit hypothesis-generating experiments. Results: We demonstrate a quantitative disparity in the differentiation ability among Tet protein deletions, with Tet2 single knockout exhibiting the most severe defect, while loss of Tet1 ¬alone or combinations of Tet genes showed a quantitatively intermediate phenotype. Using a combination of transcriptomic and epigenomic approaches we demonstrate an increase in DNA hypermethylation and a divergence of transcriptional profiles in pluripotency among Tet deletions, with loss of Tet2 having the most profound effect in undifferentiated ESCs. Conclusions: We conclude that loss of Tet2 has the most dramatic effect both on the phenotype of ESCs and the transcriptome compared to other genotypes. While loss of Tet proteins increased DNA hypermethylation, especially in gene promoters, these changes in DNA methylation did not correlate with gene expression changes. Thus, while loss of different Tet proteins alters DNA methylation, this change does not appear to be directly responsible for transcriptome changes. Thus, loss of Tet proteins likely regulates the transcriptome epigenetically both through altering 5mC but also through additional mechanisms. Nonetheless, the transcriptome changes in pluripotent Tet2-/- ESCs compared to wild-type implies that the disparities in differentiation can be partially attributed to baseline alterations in gene expression.


2019 ◽  
Author(s):  
Michael J Reimer ◽  
Kirthi Pulakanti ◽  
Linzheng Shi ◽  
Alex Abel ◽  
Mingyu Liang ◽  
...  

Abstract Background: The Tet protein family (Tet1, Tet2, and Tet3) regulate DNA methylation through conversion of 5-methylcytosine to 5-hydroxymethylcytosine which can ultimately result in DNA demethylation and play a critical role during early mammalian development and pluripotency¬. While multiple groups have generated knockouts combining loss of different Tet proteins in murine embryonic stem cells (ESCs), differences in genetic background and approaches has made it difficult to directly compare results and discern the direct mechanism by which Tet proteins regulate the transcriptome. To address this concern, we utilized genomic editing in an isogenic pluripotent background which permitted a quantitative, flow-cytometry based measurement of pluripotency in combination with genome-wide assessment of gene expression and DNA methylation changes. Our ultimate goal was to generate a resource of large-scale datasets to permit hypothesis-generating experiments. Results: We demonstrate a quantitative disparity in the differentiation ability among Tet protein deletions, with Tet2 single knockout exhibiting the most severe defect, while loss of Tet1 ¬alone or combinations of Tet genes showed a quantitatively intermediate phenotype. Using a combination of transcriptomic and epigenomic approaches we demonstrate an increase in DNA hypermethylation and a divergence of transcriptional profiles in pluripotency among Tet deletions, with loss of Tet2 having the most profound effect in undifferentiated ESCs. Conclusions: We conclude that loss of Tet2 has the most dramatic effect both on the phenotype of ESCs and the transcriptome compared to other genotypes. While loss of Tet proteins increased DNA hypermethylation, especially in gene promoters, these changes in DNA methylation did not correlate with gene expression changes. Thus, while loss of different Tet proteins alters DNA methylation, this change does not appear to be directly responsible for transcriptome changes. Thus, loss of Tet proteins likely regulates the transcriptome epigenetically both through altering 5mC but also through additional mechanisms. Nonetheless, the transcriptome changes in pluripotent Tet2-/- ESCs compared to wild-type implies that the disparities in differentiation can be partially attributed to baseline alterations in gene expression.


2019 ◽  
Author(s):  
Michael J Reimer ◽  
Kirthi Pulakanti ◽  
Linzheng Shi ◽  
Alex Abel ◽  
Mingyu Liang ◽  
...  

Abstract Background: The Tet protein family (Tet1, Tet2, and Tet3) regulate DNA methylation through conversion of 5-methylcytosine to 5-hydroxymethylcytosine which can ultimately result in DNA demethylation and play a critical role during early mammalian development and pluripotency¬. While multiple groups have generated knockouts combining loss of different Tet proteins in murine embryonic stem cells (ESCs), differences in genetic background and approaches has made it difficult to directly compare results and discern the direct mechanism by which Tet proteins regulate the transcriptome. To address this concern, we utilized genomic editing in an isogenic pluripotent background which permitted a quantitative, flow-cytometry based measurement of pluripotency in combination with genome-wide assessment of gene expression and DNA methylation changes. Our ultimate goal was to generate a resource of large-scale datasets to permit hypothesis-generating experiments. Results: We demonstrate a quantitative disparity in the differentiation ability among Tet protein deletions, with Tet2 single knockout exhibiting the most severe defect, while loss of Tet1 ¬alone or combinations of Tet genes showed a quantitatively intermediate phenotype. Using a combination of transcriptomic and epigenomic approaches we demonstrate an increase in DNA hypermethylation and a divergence of transcriptional profiles in pluripotency among Tet deletions, with loss of Tet2 having the most profound effect in undifferentiated ESCs. Conclusions: We conclude that loss of Tet2 has the most dramatic effect both on the phenotype of ESCs and the transcriptome compared to other genotypes. While loss of Tet proteins increased DNA hypermethylation, especially in gene promoters, these changes in DNA methylation did not correlate with gene expression changes. Thus, while loss of different Tet proteins alters DNA methylation, this change does not appear to be directly responsible for transcriptome changes. Thus, loss of Tet proteins likely regulates the transcriptome epigenetically both through altering 5mC but also through additional mechanisms. Nonetheless, the transcriptome changes in pluripotent Tet2-/- ESCs compared to wild-type implies that the disparities in differentiation can be partially attributed to baseline alterations in gene expression.


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Shaohai Fang ◽  
Jia Li ◽  
Yang Xiao ◽  
Minjung Lee ◽  
Lei Guo ◽  
...  

Abstract Tet-mediated DNA demethylation plays an important role in shaping the epigenetic landscape and chromatin accessibility to control gene expression. While several studies demonstrated pivotal roles of Tet in regulating embryonic development, little is known about their functions in heart development. Here we analyze DNA methylation and hydroxymethylation dynamics during early cardiac development in both human and mice. We find that cardiac-specific deletion of Tet2 and Tet3 in mice (Tet2/3-DKO) leads to ventricular non-compaction cardiomyopathy (NCC) with embryonic lethality. Single-cell RNA-seq analyses reveal a reduction in cardiomyocyte numbers and transcriptional reprogramming in cardiac tissues upon Tet2/3 depletion. Impaired DNA demethylation and reduced chromatin accessibility in Tet2/3-DKO mice further compromised Ying-yang1 (YY1) binding to its genomic targets, and perturbed high-order chromatin organization at key genes involved in heart development. Our studies provide evidence of the physiological role of Tet in regulating DNA methylation dynamics and chromatin organization during early heart development.


Development ◽  
2021 ◽  
Author(s):  
Christopher J. Derrick ◽  
Eric J. G. Pollitt ◽  
Ashley Sanchez Sevilla Uruchurtu ◽  
Farah Hussein ◽  
Andrew J. Grierson ◽  
...  

During early vertebrate heart development the heart transitions from a linear tube to a complex asymmetric structure, a morphogenetic process which occurs simultaneously with growth of the heart. Cardiac growth during early heart morphogenesis is driven by deployment of cells from the Second Heart Field (SHF) into both poles of the heart. Laminin is a core component of the extracellular matrix (ECM), and although mutations in laminin subunits are linked with cardiac abnormalities, no role for laminin has been identified in early vertebrate heart morphogenesis. We identified tissue-specific expression of laminin genes in the developing zebrafish heart, supporting a role for laminins in heart morphogenesis. Analysis of heart development in lamb1a zebrafish mutant embryos reveals mild morphogenetic defects and progressive cardiomegaly, and that Lamb1a functions to limit heart size during cardiac development by restricting SHF addition. lamb1a mutants exhibit hallmarks of altered haemodynamics, and blocking cardiac contractility in lamb1a mutants rescues heart size and atrial SHF addition. Together this suggests that laminin mediates interactions between SHF deployment and cardiac biomechanics during heart development and growth in the developing embryo.


Cell Reports ◽  
2017 ◽  
Vol 18 (4) ◽  
pp. 1019-1032 ◽  
Author(s):  
Zhengfang Zhou ◽  
Jingying Wang ◽  
Chaoshe Guo ◽  
Weiting Chang ◽  
Jian Zhuang ◽  
...  

Nutrients ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 181 ◽  
Author(s):  
Guillaume Blin ◽  
Marjorie Liand ◽  
Claire Mauduit ◽  
Hassib Chehade ◽  
Mohamed Benahmed ◽  
...  

Heart diseases are a leading cause of death. While the link between early exposure to nutritional excess and heart disease risk is clear, the molecular mechanisms involved are poorly understood. In the developmental programming field, increasing evidence is pointing out the critical role of epigenetic mechanisms. Among them, polycomb repressive complex 2 (PRC2) and DNA methylation play a critical role in heart development and pathogenesis. In this context, we aimed at evaluating the role of these epigenetic marks in the long-term cardiac alterations induced by early dietary challenge. Using a model of rats exposed to maternal high-fat diet during gestation and lactation, we evaluated cardiac alterations at adulthood. Expression levels of PRC2 components, its histone marks di- and trimethylated histone H3 (H3K27me2/3), associated histone mark (ubiquitinated histone H2A, H2AK119ub1) and target genes were measured by Western blot. Global DNA methylation level and DNA methyl transferase 3B (DNMT3B) protein levels were measured. Maternal high-fat diet decreased H3K27me3, H2Ak119ub1 and DNA methylation levels, down-regulated the enhancer of zeste homolog 2 (EZH2), and DNMT3B expression. The levels of the target genes, isl lim homeobox 1 (Isl1), six homeobox 1 (Six1) and mads box transcription enhancer factor 2, polypeptide C (Mef2c), involved in cardiac pathogenesis were up regulated. Overall, our data suggest that the programming of cardiac alterations by maternal exposure to high-fat diet involves the derepression of pro-fibrotic and pro-hypertrophic genes through the induction of EZH2 and DNMT3B deficiency.


2021 ◽  
Vol 5 (1) ◽  
pp. e202101228
Author(s):  
Xiaokang Wang ◽  
Wojciech Rosikiewicz ◽  
Yurii Sedkov ◽  
Tanner Martinez ◽  
Baranda S Hansen ◽  
...  

DNA methylation at enhancers and CpG islands usually leads to gene repression, which is counteracted by DNA demethylation through the TET protein family. However, how TET enzymes are recruited and regulated at these genomic loci is not fully understood. Here, we identify TET2, the glycosyltransferase OGT and a previously undescribed proline and serine rich protein, PROSER1 as interactors of UTX, a component of the enhancer-associated MLL3/4 complexes. We find that PROSER1 mediates the interaction between OGT and TET2, thus promoting TET2 O-GlcNAcylation and protein stability. In addition, PROSER1, UTX, TET1/2, and OGT colocalize on many genomic elements genome-wide. Loss of PROSER1 results in lower enrichment of UTX, TET1/2, and OGT at enhancers and CpG islands, with a concomitant increase in DNA methylation and transcriptional down-regulation of associated target genes and increased DNA hypermethylation encroachment at H3K4me1-predisposed CpG islands. Furthermore, we provide evidence that PROSER1 acts as a more general regulator of OGT activity by controlling O-GlcNAcylation of multiple other chromatin signaling pathways. Taken together, this study describes for the first time a regulator of TET2 O-GlcNAcylation and its implications in mediating DNA demethylation at UTX-dependent enhancers and CpG islands and supports an important role for PROSER1 in regulating the function of various chromatin-associated proteins via OGT-mediated O-GlcNAcylation.


2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Wenzheng Liu ◽  
Guanhua Wu ◽  
Fei Xiong ◽  
Yongjun Chen

Abstract Background The ten-eleven translocation 1 (TET1) protein is a 5-methylcytosine hydroxylase that belongs to the TET protein family of human α-ketoglutarate oxygenases. TET1 recognizes and binds to regions of high genomic 5′-CpG-3′ dinucleotide density, such as CpG islands, initiates the DNA demethylation program, and maintains DNA methylation and demethylation balance to maintain genomic methylation homeostasis and achieve epigenetic regulation. This article reviews the recent research progress of TET1 in the mechanism of demethylation, stem cells and immunity, various malignant tumours and other clinical diseases. Conclusion TET1 acts as a key factor mediating demethylation, the mechanism of which still remains to be investigated in detail. TET1 is also critical in maintaining the differentiation pluripotency of embryonic stem cells and plays anti- or oncogenic roles in combination with different signalling pathways in different tumours. In certain tumours, its role is still controversial. In addition, the noncatalytic activity of TET1 has gradually attracted attention and has become a new direction of research in recent years.


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