Pcgf1 regulates early neural tube development through histone methylation in zebrafish

2020 ◽  
Author(s):  
Xinyue Li ◽  
Guangyu Ji ◽  
Juan Zhou ◽  
Jingyi Du ◽  
Xian Li ◽  
...  

Abstract Objective Early neural tube development in the embryo includes neural induction and self-renewal of neural stem cells (NSCs). The abnormal of neural tube development could lead to neural tube defects. The research on the mechanism of neural induction is the key to reveal the pathogenesis of the abnormal of neural tube. Though studies have confirmed a genetic component, the responsible mechanisms for the abnormal of neural tube are still largely unknown. Polycomb repressive complex 1 (PRC1) plays an important role in regulating early embryonic development, and has been sub-classified into six major complexes based on the presence of a Pcgf subunit. Pcgf1, as one of six Pcgf paralogs, is an important requirement in early embryonic brain development. Here, we intended to investigate the role and mechanism of Pcgf1 in early neural tube development of zebrafish embryos. Material and methods Morpholino (MO) antisense oligonucleotides were used to construct a Pcgf1 loss-of function zebrafish model. We analyzed the phenotype of zebrafish embryos and the expression of related genes in the process of neural induction by in situ hybridization, immunolabelling and RNA-sEq. The regulation of histone modifications on gene was detected by western blot and chromatin immunoprecipitation. Results In this study, we found that zebrafish embryos exhibited small head and reduced or even absence of telencephalon after inhibiting the expression of Pcgf1. Moreover, the neural induction process of zebrafish embryos was abnormal, and the subsequent NSCs self-renewal was inhibited under the inhibition of Pcgf1. RNA-seq and gene ontology (GO) analysis identified that the differentially expressed genes were enriched in many functional categories which related to the development phenotype. Finally, our results showed that Pcgf1 regulated the trimethylation of histone H3K27 in the Ngn1 and Otx2 promoter regions, and the levels of H3K4me3 at the promoters of Pou5f3 and Nanog. Conclusion Together, our data for the first time demonstrate that Pcgf1 plays an essential role in early neural induction phase through histone methylation in neural tube development. Our findings reveal a critical context-specific function for Pcgf1 in directing PRC1 to control cell fate.

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Xian Li ◽  
Wenjuan Zhou ◽  
Xinyue Li ◽  
Ming Gao ◽  
Shufang Ji ◽  
...  

Abstract Objective Neural tube defects (NTDs) are the most serious and common birth defects in the clinic. The SRY-related HMG box B1 (SoxB1) gene family has been implicated in different processes of early embryogenesis. Sox19b is a maternally expressed gene in the SoxB1 family that is found in the region of the presumptive central nervous system (CNS), but its role and mechanism in embryonic neural stem cells (NSCs) during neural tube development have not yet been explored. Considering that Sox19b is specific to bony fish, we intended to investigate the role and mechanism of Sox19b in neural tube development in zebrafish embryos. Material and methods Morpholino (MO) antisense oligonucleotides were used to construct a Sox19b loss-of-function zebrafish model. The phenotype and the expression of related genes were analysed by in situ hybridization and immunolabelling. Epigenetic modifications were detected by western blot and chromatin immunoprecipitation. Results In this study, we found that zebrafish embryos exhibited a reduced or even deleted forebrain phenotype after the expression of the Sox19b gene was inhibited. Moreover, we found for the first time that knockdown of Sox19b reduced the proliferation of NSCs; increased the transcription levels of Ngn1, Ascl1, HuC, Islet1, and cyclin-dependent kinase (CDK) inhibitors; and led to premature differentiation of NSCs. Finally, we found that knockdown of Sox19b decreased the levels of EZH2/H3K27me3 and decreased the level of H3K27me3 at the promoters of Ngn1 and ascl1a. Conclusion Together, our data demonstrate that Sox19b plays an essential role in early NSC proliferation and differentiation through EZH2-mediated histone methylation in neural tube development. This study established the role of transcription factor Sox19b and epigenetic factor EZH2 regulatory network on NSC development, which provides new clues and theoretical guidance for the clinical treatment of neural tube defects.


Author(s):  
Xinyue Li ◽  
Guangyu Ji ◽  
Juan Zhou ◽  
Jingyi Du ◽  
Xian Li ◽  
...  

The neural induction constitutes the initial step in the generation of the neural tube. Pcgf1, as one of six Pcgf paralogs, is a maternally expressed gene, but its role and mechanism in early neural induction during neural tube development have not yet been explored. In this study, we found that zebrafish embryos exhibited a small head and reduced or even absence of telencephalon after inhibiting the expression of Pcgf1. Moreover, the neural induction process of zebrafish embryos was abnormally activated, and the subsequent NSC self-renewal was inhibited after injecting the Pcgf1 MO. The results of in vitro also showed that knockdown of Pcgf1 increased the expression levels of the neural markers Pax6, Pou3f1, and Zfp521, but decreased the expression levels of the pluripotent markers Oct4, Hes1, and Nanog, which further confirmed that Pcgf1 was indispensable for maintaining the pluripotency of P19 cells. To gain a better understanding of the role of Pcgf1 in early development, we analyzed mRNA profiles from Pcgf1-deficient P19 cells using RNA-seq. We found that the differentially expressed genes were enriched in many functional categories, which related to the development phenotype, and knockdown of Pcgf1 increased the expression of histone demethylases. Finally, our results showed that Pcgf1 loss-of-function decreased the levels of transcriptional repression mark H3K27me3 at the promoters of Ngn1 and Otx2, and the levels of transcriptional activation mark H3K4me3 at the promoters of Pou5f3 and Nanog. Together, our findings reveal that Pcgf1 might function as both a facilitator for pluripotent maintenance and a repressor for neural induction.


Science ◽  
2019 ◽  
Vol 363 (6432) ◽  
pp. 1217-1222 ◽  
Author(s):  
Abhishek A. Chakraborty ◽  
Tuomas Laukka ◽  
Matti Myllykoski ◽  
Alison E. Ringel ◽  
Matthew A. Booker ◽  
...  

Oxygen sensing is central to metazoan biology and has implications for human disease. Mammalian cells express multiple oxygen-dependent enzymes called 2-oxoglutarate (OG)-dependent dioxygenases (2-OGDDs), but they vary in their oxygen affinities and hence their ability to sense oxygen. The 2-OGDD histone demethylases control histone methylation. Hypoxia increases histone methylation, but whether this reflects direct effects on histone demethylases or indirect effects caused by the hypoxic induction of the HIF (hypoxia-inducible factor) transcription factor or the 2-OG antagonist 2-hydroxyglutarate (2-HG) is unclear. Here, we report that hypoxia promotes histone methylation in a HIF- and 2-HG–independent manner. We found that the H3K27 histone demethylase KDM6A/UTX, but not its paralog KDM6B, is oxygen sensitive. KDM6A loss, like hypoxia, prevented H3K27 demethylation and blocked cellular differentiation. Restoring H3K27 methylation homeostasis in hypoxic cells reversed these effects. Thus, oxygen directly affects chromatin regulators to control cell fate.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 3301-3301
Author(s):  
Shaun David Patterson ◽  
Matthew E Massett ◽  
Helen Wheadon ◽  
Xu Huang ◽  
Heather G Jørgensen ◽  
...  

Abstract Background: Acute myeloid leukemia (AML) arises due to an accumulation of genetic lesions within myeloid progenitors and oncogenic transformation is often characterised by disordered transcription. Recently the histone lysine demethylase KDM4A was shown to be essential for AML blast survival and self-renewal. shRNA knockdown (KD) of KDM4A led to downregulated expression of the transcription factor NFATC2 an MLL-AF9 AML model, suggesting that it is a key target of KDM4A oncogenic function. The Nuclear Factor of Activated T Cells (NFAT) family of transcription factors control cell cycle genes and self-renewal pathways in hematopoietic tissues and are well-defined as oncogenic regulators in various malignancies. NFATs have recently been attributed roles in the development of FLT3 ITD AML and resistance to tyrosine kinase inhibitors (TKIs) in myeloid leukemias but there is little evidence detailing the role(s) of NFATC2 specifically in AML. We hypothesized that NFATc2 activity is essential for the survival of AML cells and the oncogenic transcriptional networks within these. Aims: To determine if AML cells are dependent on NFATC2 for survival and to elucidate the transcriptional and binding targets of NFATc2 in AML. Methods: NFATC2 was depleted using shRNA KD in numerous cell line models of AML and putative transcriptional targets were elucidated using RNA-seq following KD. Binding targets of NFATc2 were determined using ChIP-seq. Transcriptomic targets of NFATc2 were validated using the Fluidigm Biomark multiplex PCR system and real time quantitative PCR. Results: KD of NFATC2 significantly impaired the colony forming capacity and expansion in liquid cultures of AML cell lines from diverse (cyto)genetic backgrounds. MLL-AF9/TP53 mut THP-1 cells showed reduced entry to the S-phase of the cell cycle and downregulation of cyclin D1 following NFATC2 depletion, suggesting that NFATC2 is critical for cell cycle progression in these cells. Overexpression of human NFATC2 in THP-1 led to an increased rate of cell growth. RNA-seq analysis of THP-1 cells with NFATC2 KD revealed >20 genes with deregulated expression (FDR<0.1), which have been validated using PCR methods. Overexpression of human NFATC2 resulted in significant deregulation of 9 of these genes (FDR<0.1), defining a subset of genes which may regulate the observed phenotype. Additionally, these top genes were not all differentially regulated in other MLL-AF9 AML cell lines MOLM-13 and NOMO-1 following NFATC2 KD. Finally, in THP-1, gene set enrichment analysis (GSEA) of sequencing results revealed that targets of MYC and calmodulin kinase STK33 were enriched within the genes perturbed by NFATC2 depletion. Targets of MYC signaling were validated by PCR in THP-1 but were not found to be deregulated in MOLM-13 following NFATC2 KD. ChIP-seq analysis of NFATc2 binding in THP-1 cells showed that >30% of NFATc2 targets were at promoter regions within 5kb of the transcription start site. Motif analysis of precipitated DNA fragments discovered two novel motifs which were enriched at NFATc2 binding sites (p<0.0001). Discussion: NFATC2 was found to be essential for expansion of AML cells in various cell line models. In the MLL-AF9 driven THP-1 model a number of putative transcriptional and genomic targets were defined, which include novel targets not previously described in AML pathogenesis and targets of MYC, an established oncogenic protein in AML. The differing expression profiles observed across AML cell lines of diverse (cyto)genetic backgrounds with NFATC2 KD suggest that the regulatory targets of NFATc2 vary depending on the cellular signaling landscape. Together with the finding that NFATC2 is indispensable for AML cell survival this study has elucidated novel roles(s) for NFATC2 in AML oncogenesis. Disclosures Massett: Kymab Ltd: Current Employment. Huang: Janssen Pharmaceutical Companies of Johnson & Johnson (China): Current Employment.


Author(s):  
Yajing Meng ◽  
Tianzhe Zhang ◽  
Ran Zheng ◽  
Song Ding ◽  
Jie Yang ◽  
...  

Epigenetic modifications play a crucial role in neurogenesis, learning, and memory, but the study of their role in early neuroectoderm commitment from pluripotent inner cell mass is relatively lacking. Here we utilized the system of directed neuroectoderm differentiation from human embryonic stem cells and identified that KDM6B, an enzyme responsible to erase H3K27me3, was the most upregulated enzyme of histone methylation during neuroectoderm differentiation by transcriptome analysis. We then constructed KDM6B-null embryonic stem cells and found strikingly that the pluripotent stem cells with KDM6B knockout exhibited much higher neuroectoderm induction efficiency. Furthermore, we constructed a series of embryonic stem cell lines knocking out the other H3K27 demethylase KDM6A, and depleting both KDM6A and KDM6B, respectively. These cell lines together confirmed that KDM6 impeded early neuroectoderm commitment. By RNA-seq, we found that the expression levels of a panel of WNT genes were significantly affected upon depletion of KDM6. Importantly, the result that WNT agonist and antagonist could abolish the differential neuroectoderm induction due to manipulating KDM6 further demonstrated that WNT was the major downstream of KDM6 during early neural induction. Moreover, we found that the chemical GSK-J1, an inhibitor of KDM6, could enhance neuroectoderm induction from both embryonic stem cells and induced pluripotent stem cells. Taken together, our findings not only illustrated the important role of the histone methylation modifier KDM6 in early neurogenesis, providing insights into the precise epigenetic regulation in cell fate determination, but also showed that the inhibitor of KDM6 could facilitate neuroectoderm differentiation from human pluripotent stem cells.


IUBMB Life ◽  
2017 ◽  
Vol 69 (9) ◽  
pp. 706-719 ◽  
Author(s):  
Juan Yu ◽  
Jianbing Mu ◽  
Qian Guo ◽  
Lihong Yang ◽  
Juan Zhang ◽  
...  

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yumeng Zhang ◽  
Jiaqi Xu ◽  
Zhili Ren ◽  
Ya Meng ◽  
Weiwei Liu ◽  
...  

Abstract Background Vitamin B3 (nicotinamide) plays important roles in metabolism as well as in SIRT and PARP pathways. It is also recently reported as a novel kinase inhibitor with multiple targets. Nicotinamide promotes pancreatic cell differentiation from human embryonic stem cells (hESCs). However, its molecular mechanism is still unclear. In order to understand the molecular mechanism involved in pancreatic cell fate determination, we analyzed the downstream pathways of nicotinamide in the derivation of NKX6.1+ pancreatic progenitors from hESCs. Methods We applied downstream modulators of nicotinamide during the induction from posterior foregut to pancreatic progenitors, including niacin, PARP inhibitor, SIRT inhibitor, CK1 inhibitor and ROCK inhibitor. The impact of those treatments was evaluated by quantitative real-time PCR, flow cytometry and immunostaining of pancreatic markers. Furthermore, CK1 isoforms were knocked down to validate CK1 function in the induction of pancreatic progenitors. Finally, RNA-seq was used to demonstrate pancreatic induction on the transcriptomic level. Results First, we demonstrated that nicotinamide promoted pancreatic progenitor differentiation in chemically defined conditions, but it did not act through either niacin-associated metabolism or the inhibition of PARP and SIRT pathways. In contrast, nicotinamide modulated differentiation through CK1 and ROCK inhibition. We demonstrated that CK1 inhibitors promoted the generation of PDX1/NKX6.1 double-positive pancreatic progenitor cells. shRNA knockdown revealed that the inhibition of CK1α and CK1ε promoted pancreatic progenitor differentiation. We then showed that nicotinamide also improved pancreatic progenitor differentiation through ROCK inhibition. Finally, RNA-seq data showed that CK1 and ROCK inhibition led to pancreatic gene expression, similar to nicotinamide treatment. Conclusions In this report, we revealed that nicotinamide promotes generation of pancreatic progenitors from hESCs through CK1 and ROCK inhibition. Furthermore, we discovered the novel role of CK1 in pancreatic cell fate determination.


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