Loss of Tet proteins impairs mouse embryonic stem cells differentiation toward cardiomyocytes progenitors
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ABSTRACT: DNA methylation mediated epigenetic regulation plays a critical role in regulating cardiomyocytes (CM) differentiation. Tet protein mediated DNA methylation oxidation have been reported to play an important role in regulating embryonic stem cell (ESC) differentiation toward different lineages. In our study, we utilized CRISPR/Cas9 based genome editing method to generated Tet single, double and triple deficient mouse ESC (mESC) expressing emGFP under NKX2.5 promoter and differentiated these cells toward CM progenitors. By modulating emGFP population as cardiac progenitor cells, we found that deletion of Tet1 and Tet2 significantly impairs mESC differentiation toward CM progenitors. Further single-cell RNA-seq analysis in differentiated control and Tet-triple knockout (TKO) mESC reveals that Tet deletion resulted in accumulation of mesoderm progenitors and impairs CM differentiation. Overexpression the catalytic domain of Tet1 could rescue the development defects in Tet-TKO mESC and restore NKX2.5 gene expression. In addition, loci-specific dCas9-Tet1CD mediated epigenome editing at Hand1 loci confirmed its directly transcriptional regulation during CM differentiation. Overall, out studies suggested that Tet protein mediated epigenomic remodeling is a genome-wide event and is essential to maintain proper transcription network during mESC differentiation toward CM progenitors.
Project description:Tet enzymes (Tet1/2/3) convert 5-methylcytosine (5mC) to 5-hydroxy-methylcytosine (5hmC) and are dynamically expressed in various embryonic and adult cell types. While loss of individual Tet enzymes or combined deficiency of Tet1/2 allows for embryogenesis, the effect of complete loss of Tet activity and 5hmC marks in development is not established. We have generated Tet1/2/3 triple knockout (TKO) mouse embryonic stem cells (ESCs) and examined their developmental potential. Combined deficiency of all three Tets depleted 5hmC and impaired ESC differentiation as seen in poorly differentiated TKO embryoid bodies (EBs) and teratomas. Consistent with impaired differentiation, TKO-ESCs contributed poorly to chimeric embryos and could not support embryonic development. Global gene expression and methylome analyses of TKO-EBs revealed promoter hypermethylation and deregulation of genes implicated in embryonic development and differentiation. These findings suggest a requirement for Tet- and 5hmC-mediated DNA demethylation in proper regulation of gene expression during differentiation of ESCs and development. To quantify global gene expression in differentiating embryoid bodies (EBs) derived from wild type (WT) and Tet triple knockout (TKO), TKO and WT mouse embryonic stem cells (ESCs) were differentiated in vitro to EBs and cultured for 10 days. RNA was extracted using Qiagen RNeasy kit and subjected to microarray analysis. Global gene expression profile of two technical replicas of WT embryoid bodies (2 samples in total) was compared to two technical replicas of two independent TKO embryoid bodies (4 TKO samples in total).
Project description:Tet enzymes (Tet1/2/3) catalyze the conversion of 5-methylcytosine (5mC) to 5-hydroxy-methylcytosine (5hmC) and are dynamically expressed in various embryonic and adult cell types. While loss of individual Tet enzymes or combined deficiency of Tet1/2 allows for embryogenesis, the effect of complete loss of Tet activity and 5hmC marks in development has not been established. To define the role of Tet enzymes and 5hmC in development we have generated Tet1, Tet2 and Tet3 triple knockout (TKO) mouse embryonic stem cells (ESCs) and examined their developmental potential in vitro and in vivo. Combined deficiency of all three Tet enzymes led to complete depletion of 5hmC and impaired ESC differentiation as seen in poorly differentiated TKO embryoid bodies and teratomas. Consistent with impaired differentiation, TKO ES cells exhibited limited contribution to the chimeric embryos and could not support embryonic development in tetraploid complementation assays. Gene expression profiles and genome wide methylome analyses of TKO embryoid bodies revealed promoter hypermethylation and deregulation of genes implicated in embryonic development and differentiation. These findings suggest a requirement for Tet and 5hmC-mediated DNA demethylation in proper regulation of gene expression during differentiation of embryonic stem cells and development. Methylation patterns in tissue samples from a series of wt and Tet1/Tet2 DKO embryos, neonates and adults were generated using ethylated DNA immunoprecipitation with antibodies against 5mC (MeDIP) and 5hmC (hMeDIP) followed by deep sequencing.
Project description:Tet enzymes (Tet1/2/3) convert 5-methylcytosine (5mC) to 5-hydroxy-methylcytosine (5hmC) and are dynamically expressed in various embryonic and adult cell types. While loss of individual Tet enzymes or combined deficiency of Tet1/2 allows for embryogenesis, the effect of complete loss of Tet activity and 5hmC marks in development is not established. We have generated Tet1/2/3 triple knockout (TKO) mouse embryonic stem cells (ESCs) and examined their developmental potential. Combined deficiency of all three Tets depleted 5hmC and impaired ESC differentiation as seen in poorly differentiated TKO embryoid bodies (EBs) and teratomas. Consistent with impaired differentiation, TKO-ESCs contributed poorly to chimeric embryos and could not support embryonic development. Global gene expression and methylome analyses of TKO-EBs revealed promoter hypermethylation and deregulation of genes implicated in embryonic development and differentiation. These findings suggest a requirement for Tet- and 5hmC-mediated DNA demethylation in proper regulation of gene expression during differentiation of ESCs and development.
Project description:Tet enzymes (Tet1/2/3) catalyze the conversion of 5-methylcytosine (5mC) to 5-hydroxy-methylcytosine (5hmC) and are dynamically expressed in various embryonic and adult cell types. While loss of individual Tet enzymes or combined deficiency of Tet1/2 allows for embryogenesis, the effect of complete loss of Tet activity and 5hmC marks in development has not been established. To define the role of Tet enzymes and 5hmC in development we have generated Tet1, Tet2 and Tet3 triple knockout (TKO) mouse embryonic stem cells (ESCs) and examined their developmental potential in vitro and in vivo. Combined deficiency of all three Tet enzymes led to complete depletion of 5hmC and impaired ESC differentiation as seen in poorly differentiated TKO embryoid bodies and teratomas. Consistent with impaired differentiation, TKO ES cells exhibited limited contribution to the chimeric embryos and could not support embryonic development in tetraploid complementation assays. Gene expression profiles and genome wide methylome analyses of TKO embryoid bodies revealed promoter hypermethylation and deregulation of genes implicated in embryonic development and differentiation. These findings suggest a requirement for Tet and 5hmC-mediated DNA demethylation in proper regulation of gene expression during differentiation of embryonic stem cells and development.
Project description:Current knowledge about the role of epigenetic modifiers in pancreas development has been exponentially increased. However, the precise function of TET dioxygenases in pancreas specification remains poorly understood. Using a stepwise human embryonic stem cell (hESC) differentiation system, TET1/TET2/TET3 triple-knockout (TKO) cells displayed severe defects in pancreatic differentiation. Whole-genome analysis revealed TET depletion led to aberrant DNA methylation and chromatin remodeling. In comparison with methylome and hydroxymethylome datasets previously generated from hESCs, we identified unique pancreas-specific hyper-methylated and hypo-hydroxymethylated regions in TKO cells, where binding of pioneer transcription factor FOXA2 was remarkably enriched. Interestingly, transduction of full-length TET1 in TKO cells effectively rescued pancreatic differentiation and the expression of PAX4, a key determinant for -cell specification. Taking these findings together with genome-wide mapping of TET1 in pancreatic progenitors, we uncovered that TET1 co-occupied at a specific subset of FOXA2-bound loci featuring high levels of active chromatin. Locus-specific DNA methylation analysis revealed significant increases of 5-methylcytosine at the PAX4 enhancer in a TET1-dependent manner, consistent with defective generation of functional beta-cells from TET1-knockout hESCs. Thus, our study not only highlights the importance of TET-dependent epigenetic regulation in pancreas development but also unveils an essential role of TET1 in establishing beta-cell identity.
Project description:Surveillance of DNA methylation in mammals is critical for genome stability and epigenetic regulation. The discovery of the ten-eleven translocation (TET) proteins catalyzing the oxidation from 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC), and 5-carboxylcytosine (5caC) revolutionized the understanding of DNA methylation dynamics. Interestingly, in recent years evidence accumulated that TET1 also harbours non-catalytic functions. However, the role and mechanism of TET1 DNA demethylation independent functions still remain poorly understood. Here, we use genome engineering and quantitative multi-omics approaches to dissect the non-catalytic role of TET1. Strikingly, we find that the majority of transcriptional regulation depends on non-catalytic functions of TET1. To gain insights into possible mechanisms by which TET1 regulates transcription independent of DNA demethylation, we asked if the loss of TET1 is accompanied by changes in the histone modificaiton landscape. To this end, we compared the relative abundances of core histone modifications between Tet1 KO, Tet1 CM and WT mESCs using quantitative LC-MS/MS analysis. Surprisingly, we observed a profound global reduction of pH4Kac and H4K20me3 as well as H3K27me3 in Tet1 KO mESC. Vice versa, the monomethylation states of the latter two residues, H3K27me1 and H4K20me1 were significantly increased in Tet1 KO. Similar to the results from the transcriptome data, most of these changes were specific to Tet1 KO cells.
Project description:The TET family of FE(II) and 2-oxoglutarate-dependent enzymes (Tet1/2/3) promote DNA demethylation by converting 5-methylcytosine to 5-hydroxymethylcytosine (5hmC), which they further oxidize into 5-formylcytosine and 5-carboxylcytosine. Tet1 is robustly expressed in mouse embryonic stem cells (mESCs) and has been implicated in mESC maintenance. Here we demonstrate that, unlike genetic deletion, RNAi-mediated depletion of Tet1 in mESCs led to a significant reduction in 5hmC and loss of mESC identity. The differentiation phenotype due to Tet1 depletion positively correlated with the extent of 5hmC loss. Meta-analyses of genomic datasets suggested interaction between Tet1 and leukemia inhibitory factor (LIF) signaling. LIF signaling is known to promote self-renewal and pluripo-tency in mESCs partly by opposing MAPK/ERK mediated differentiation. Withdrawal of LIF leads to differentiation of mESCs. We discovered that Tet1 depletion impaired LIF-dependent Stat3-mediated gene activation by affecting Stat3's ability to bind to its target sites on chromatin. Nanog overexpression or inhibition of MAPK/ERK signaling, both known to maintain mESCs in the absence of LIF, rescued Tet1 depletion, further supporting the dependence of LIF/Stat3 signaling on Tet1. These data support the conclusion that analysis of mESCs in the hours/days immediately following efficient Tet1 depletion reveals Tet1’s normal physiological role in maintaining the pluripotent state that may be subject to homeostatic compensation in genetic models. Genome-wide mapping of 5hmC and microarray gene expression profiling in E14Tg2a mESCs after transfection with indicated siRNAs: Tet1 siRNA #1 (Invitrogen, MSS284895), Tet1 siRNA #2 (Invitrogen, MSS284897), and Control siRNA duplex targeting firefly luciferase.
Project description:The TET family of FE(II) and 2-oxoglutarate-dependent enzymes (Tet1/2/3) promote DNA demethylation by converting 5-methylcytosine to 5-hydroxymethylcytosine (5hmC), which they further oxidize into 5-formylcytosine and 5-carboxylcytosine. Tet1 is robustly expressed in mouse embryonic stem cells (mESCs) and has been implicated in mESC maintenance. Here we demonstrate that, unlike genetic deletion, RNAi-mediated depletion of Tet1 in mESCs led to a significant reduction in 5hmC and loss of mESC identity. The differentiation phenotype due to Tet1 depletion positively correlated with the extent of 5hmC loss. Meta-analyses of genomic datasets suggested interaction between Tet1 and leukemia inhibitory factor (LIF) signaling. LIF signaling is known to promote self-renewal and pluripo-tency in mESCs partly by opposing MAPK/ERK mediated differentiation. Withdrawal of LIF leads to differentiation of mESCs. We discovered that Tet1 depletion impaired LIF-dependent Stat3-mediated gene activation by affecting Stat3's ability to bind to its target sites on chromatin. Nanog overexpression or inhibition of MAPK/ERK signaling, both known to maintain mESCs in the absence of LIF, rescued Tet1 depletion, further supporting the dependence of LIF/Stat3 signaling on Tet1. These data support the conclusion that analysis of mESCs in the hours/days immediately following efficient Tet1 depletion reveals Tet1M-bM-^@M-^Ys normal physiological role in maintaining the pluripotent state that may be subject to homeostatic compensation in genetic models. Genome-wide mapping of 5hmC and microarray gene expression profiling in E14Tg2a mESCs after transfection with indicated siRNAs: Tet1 siRNA #1 (Invitrogen, MSS284895), Tet1 siRNA #2 (Invitrogen, MSS284897), and Control siRNA duplex targeting firefly luciferase.
Project description:Gene expression with RNA-seq for inducible Tet TKO (Tet iTKO) mESCs compared with control mouse ESCs (mESC) after 6.5 days in vitro culture after tamoxifen treatment
Project description:The TET family of FE(II) and 2-oxoglutarate-dependent enzymes (Tet1/2/3) promote DNA demethylation by converting 5-methylcytosine to 5-hydroxymethylcytosine (5hmC), which they further oxidize into 5-formylcytosine and 5-carboxylcytosine. Tet1 is robustly expressed in mouse embryonic stem cells (mESCs) and has been implicated in mESC maintenance. Here we demonstrate that, unlike genetic deletion, RNAi-mediated depletion of Tet1 in mESCs led to a significant reduction in 5hmC and loss of mESC identity. The differentiation phenotype due to Tet1 depletion positively correlated with the extent of 5hmC loss. Meta-analyses of genomic datasets suggested interaction between Tet1 and leukemia inhibitory factor (LIF) signaling. LIF signaling is known to promote self-renewal and pluripo-tency in mESCs partly by opposing MAPK/ERK mediated differentiation. Withdrawal of LIF leads to differentiation of mESCs. We discovered that Tet1 depletion impaired LIF-dependent Stat3-mediated gene activation by affecting Stat3's ability to bind to its target sites on chromatin. Nanog overexpression or inhibition of MAPK/ERK signaling, both known to maintain mESCs in the absence of LIF, rescued Tet1 depletion, further supporting the dependence of LIF/Stat3 signaling on Tet1. These data support the conclusion that analysis of mESCs in the hours/days immediately following efficient Tet1 depletion reveals Tet1’s normal physiological role in maintaining the pluripotent state that may be subject to homeostatic compensation in genetic models.