scholarly journals Enhancer priming by H3K4 methyltransferase MLL4 controls cell fate transition

2016 ◽  
Vol 113 (42) ◽  
pp. 11871-11876 ◽  
Author(s):  
Chaochen Wang ◽  
Ji-Eun Lee ◽  
Binbin Lai ◽  
Todd S. Macfarlan ◽  
Shiliyang Xu ◽  
...  

Transcriptional enhancers control cell-type–specific gene expression. Primed enhancers are marked by histone H3 lysine 4 (H3K4) mono/di-methylation (H3K4me1/2). Active enhancers are further marked by H3K27 acetylation (H3K27ac). Mixed-lineage leukemia 4 (MLL4/KMT2D) is a major enhancer H3K4me1/2 methyltransferase with functional redundancy with MLL3 (KMT2C). However, its role in cell fate maintenance and transition is poorly understood. Here, we show in mouse embryonic stem cells (ESCs) that MLL4 associates with, but is surprisingly dispensable for the maintenance of, active enhancers of cell-identity genes. As a result, MLL4 is dispensable for cell-identity gene expression and self-renewal in ESCs. In contrast, MLL4 is required for enhancer-binding of H3K27 acetyltransferase p300, enhancer activation, and induction of cell-identity genes during ESC differentiation. MLL4 protein, rather than MLL4-mediated H3K4 methylation, controls p300 recruitment to enhancers. We also show that, in somatic cells, MLL4 is dispensable for maintaining cell identity but essential for reprogramming into induced pluripotent stem cells. These results indicate that, although enhancer priming by MLL4 is dispensable for cell-identity maintenance, it controls cell fate transition by orchestrating p300-mediated enhancer activation.

Oncogene ◽  
2020 ◽  
Vol 39 (43) ◽  
pp. 6633-6646 ◽  
Author(s):  
Ye Chen ◽  
Liang Xu ◽  
Ruby Yu-Tong Lin ◽  
Markus Müschen ◽  
H. Phillip Koeffler

Abstract Transcription factors (TFs) coordinate the on-and-off states of gene expression typically in a combinatorial fashion. Studies from embryonic stem cells and other cell types have revealed that a clique of self-regulated core TFs control cell identity and cell state. These core TFs form interconnected feed-forward transcriptional loops to establish and reinforce the cell-type-specific gene-expression program; the ensemble of core TFs and their regulatory loops constitutes core transcriptional regulatory circuitry (CRC). Here, we summarize recent progress in computational reconstitution and biologic exploration of CRCs across various human malignancies, and consolidate the strategy and methodology for CRC discovery. We also discuss the genetic basis and therapeutic vulnerability of CRC, and highlight new frontiers and future efforts for the study of CRC in cancer. Knowledge of CRC in cancer is fundamental to understanding cancer-specific transcriptional addiction, and should provide important insight to both pathobiology and therapeutics.


Cells ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3365
Author(s):  
Gabriela Maria Guerra ◽  
Doreen May ◽  
Torsten Kroll ◽  
Philipp Koch ◽  
Marco Groth ◽  
...  

SMG6 is an endonuclease, which cleaves mRNAs during nonsense-mediated mRNA decay (NMD), thereby regulating gene expression and controling mRNA quality. SMG6 has been shown as a differentiation license factor of totipotent embryonic stem cells. To investigate whether it controls the differentiation of lineage-specific pluripotent progenitor cells, we inactivated Smg6 in murine embryonic neural stem cells. Nestin-Cre-mediated deletion of Smg6 in mouse neuroprogenitor cells (NPCs) caused perinatal lethality. Mutant mice brains showed normal structure at E14.5 but great reduction of the cortical NPCs and late-born cortical neurons during later stages of neurogenesis (i.e., E18.5). Smg6 inactivation led to dramatic cell death in ganglionic eminence (GE) and a reduction of interneurons at E14.5. Interestingly, neurosphere assays showed self-renewal defects specifically in interneuron progenitors but not in cortical NPCs. RT-qPCR analysis revealed that the interneuron differentiation regulators Dlx1 and Dlx2 were reduced after Smg6 deletion. Intriguingly, when Smg6 was deleted specifically in cortical and hippocampal progenitors, the mutant mice were viable and showed normal size and architecture of the cortex at E18.5. Thus, SMG6 regulates cell fate in a cell type-specific manner and is more important for neuroprogenitors originating from the GE than for progenitors from the cortex.


2021 ◽  
Vol 12 ◽  
Author(s):  
Rongpu Jia ◽  
Yu Gao ◽  
Song Guo ◽  
Si Li ◽  
Liangji Zhou ◽  
...  

Trophoblast stem cells (TSCs) are derived from blastocysts and the extra-embryonic ectoderm (ExE) of post-implantation embryos and play a significant role in fetal development, but the roles that TSCs play in the earlier status of fetal diseases need further exploration. Super enhancers (SEs) are dense clusters of stitched enhancers that control cell identity determination and disease development and may participate in TSC differentiation. We identified key cell identity genes regulated by TSC-SEs via integrated analysis of H3K27ac and H3K4me1 chromatin immunoprecipitation sequencing (ChIP-seq), RNA-sequencing (RNA-seq) and ATAC-sequencing (ATAC-seq) data. The identified key TSC identity genes regulated by SEs, such as epidermal growth factor receptor (EGFR), integrin β5 (ITGB5) and Paxillin (Pxn), were significantly upregulated during TSC differentiation, and the transcription network mediated by TSC-SEs enriched in terms like focal adhesion and actin cytoskeleton regulation related to differentiation of TSCs. Additionally, the increased chromatin accessibility of the key cell identity genes verified by ATAC-seq further demonstrated the regulatory effect of TSC-SEs on TSC lineage commitment. Our results illustrated the significant roles of the TSC-SE-regulated network in TSC differentiation, and identified key TSC identity genes EGFR, ITGB5 and Pxn, providing novel insight into TSC differentiation and lays the foundation for future studies on embryo implantation and related diseases.


2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Feikun Yang ◽  
Dean W. Richardson

The tendon is highly prone to injury, overuse, or age-related degeneration in both humans and horses. Natural healing of injured tendon is poor, and cell-based therapeutic treatment is still a significant clinical challenge. In this study, we extensively investigated the expression of tenogenic genes in equine bone marrow mesenchymal stem cells (BMSCs) and tenocyte-derived induced pluripotent stem cells (teno-iPSCs) stimulated by growth factors (TGF-β3 and BMP12) combined with ectopic expression of tenogenic transcription factor MKX or cyclic uniaxial mechanical stretch. Western blotting revealed that TGF-β3 and BMP12 increased the expression of transcription factors SCX and MKX in both cells, but the tenocyte marker tenomodulin (TNMD) was detected only in BMSCs and upregulated by either inducer. On the other hand, quantitative real-time PCR showed that TGF-β3 increased the expression of EGR1, COL1A2, FMOD, and TNC in BMSCs and SCX, COL1A2, DCN, FMOD, and TNC in teno-iPSCs. BMP12 treatment elevated SCX, MKX, DCN, FMOD, and TNC in teno-iPSCs. Overexpression of MKX increased SCX, DCN, FMOD, and TNC in BMSCs and EGR1, COL1A2, DCN, FMOD, and TNC in teno-iPSCs; TGF-β3 further enhanced TNC in BMSCs. Moreover, mechanical stretch increased SCX, EGR1, DCN, ELN, and TNC in BMSCs and SCX, MKX, EGR1, COL1A2, DCN, FMOD, and TNC in teno-iPSCs; TGF-β3 tended to further elevate SCX, ELN, and TNC in BMSCs and SCX, MKX, COL1A2, DCN, and TNC in teno-iPSCs, while BMP12 further uptrended the expression of SCX and DCN in BMSCs and DCN in teno-iPSCs. Additionally, the aforementioned tenogenic inducers also affected the expression of signaling regulators SMAD7, ETV4, and SIRT1 in BMSCs and teno-iPSCs. Taken together, our data demonstrate that, in respect to the tenocyte-lineage-specific gene expression, BMSCs and teno-iPSCs respond differently to the tenogenic stimuli, which may affect the outcome of their application in tendon repair or regeneration.


2021 ◽  
Author(s):  
Candice Byers ◽  
Catrina Spruce ◽  
Haley J. Fortin ◽  
Anne Czechanski ◽  
Steven C. Munger ◽  
...  

AbstractGenetically diverse pluripotent stem cells (PSCs) display varied, heritable responses to differentiation cues in the culture environment. By harnessing these disparities through derivation of embryonic stem cells (ESCs) from the BXD mouse genetic reference panel, along with C57BL/6J (B6) and DBA/2J (D2) parental strains, we demonstrate genetically determined biases in lineage commitment and identify major regulators of the pluripotency epigenome. Upon transition to formative pluripotency using epiblast-like cells (EpiLCs), B6 quickly dissolves naïve networks adopting gene expression modules indicative of neuroectoderm lineages; whereas D2 retains aspects of naïve pluripotency with little bias in differentiation. Genetic mapping identifies 6 major trans-acting loci co-regulating chromatin accessibility and gene expression in ESCs and EpiLCs, indicating a common regulatory system impacting cell state transition. These loci distally modulate occupancy of pluripotency factors, including TRIM28, P300, and POU5F1, at hundreds of regulatory elements. One trans-acting locus on Chr 12 primarily impacts chromatin accessibility in ESCs; while in EpiLCs the same locus subsequently influences gene expression, suggesting early chromatin priming. Consequently, the distal gene targets of this locus are enriched for neurogenesis genes and were more highly expressed when cells carried B6 haplotypes at this Chr 12 locus, supporting genetic regulation of biases in cell fate. Spontaneous formation of embryoid bodies validated this with B6 showing a propensity towards neuroectoderm differentiation and D2 towards definitive endoderm, confirming the fundamental importance of genetic variation influencing cell fate decisions.


2020 ◽  
Vol 295 (51) ◽  
pp. 17659-17671
Author(s):  
Nicole Ziegler ◽  
Erik Bader ◽  
Alexey Epanchintsev ◽  
Daniel Margerie ◽  
Aimo Kannt ◽  
...  

AMP-activated protein kinase (AMPK) is a key regulator of energy metabolism that phosphorylates a wide range of proteins to maintain cellular homeostasis. AMPK consists of three subunits: α, β, and γ. AMPKα and β are encoded by two genes, the γ subunit by three genes, all of which are expressed in a tissue-specific manner. It is not fully understood, whether individual isoforms have different functions. Using RNA-Seq technology, we provide evidence that the loss of AMPKβ1 and AMPKβ2 lead to different gene expression profiles in human induced pluripotent stem cells (hiPSCs), indicating isoform-specific function. The knockout of AMPKβ2 was associated with a higher number of differentially regulated genes than the deletion of AMPKβ1, suggesting that AMPKβ2 has a more comprehensive impact on the transcriptome. Bioinformatics analysis identified cell differentiation as one biological function being specifically associated with AMPKβ2. Correspondingly, the two isoforms differentially affected lineage decision toward a cardiac cell fate. Although the lack of PRKAB1 impacted differentiation into cardiomyocytes only at late stages of cardiac maturation, the availability of PRKAB2 was indispensable for mesoderm specification as shown by gene expression analysis and histochemical staining for cardiac lineage markers such as cTnT, GATA4, and NKX2.5. Ultimately, the lack of AMPKβ1 impairs, whereas deficiency of AMPKβ2 abrogates differentiation into cardiomyocytes. Finally, we demonstrate that AMPK affects cellular physiology by engaging in the regulation of hiPSC transcription in an isoform-specific manner, providing the basis for further investigations elucidating the role of dedicated AMPK subunits in the modulation of gene expression.


2019 ◽  
Vol 119 (05) ◽  
pp. 716-725 ◽  
Author(s):  
Xianguo Kong ◽  
Lin Ma ◽  
Edward Chen ◽  
Chad Shaw ◽  
Leonard Edelstein

AbstractMegakaryopoiesis produces specialized haematopoietic stem cells in the bone marrow that give rise to megakaryocytes which ultimately produce platelets. Defects in megakaryopoiesis can result in altered platelet counts and physiology, leading to dysfunctional haemostasis and thrombosis. Additionally, dysregulated megakaryopoiesis is also associated with myeloid pathologies. Transcription factors play critical roles in cell differentiation by regulating the temporal and spatial patterns of gene expression which ultimately decide cell fate. Several transcription factors have been described as regulating megakaryopoiesis including myocyte enhancer factor 2C (MEF2C); however, the genes regulated by MEF2C that influence megakaryopoiesis have not been reported. Using chromatin immunoprecipitation-sequencing and Gene Ontology data we identified five candidate genes that are bound by MEF2C and regulate megakaryopoiesis: MOV10, AGO3, HDAC1, RBBP5 and WASF2. To study expression of these genes, we silenced MEF2C gene expression in the Meg01 megakaryocytic cell line and in induced pluripotent stem cells by CRISPR/Cas9 editing. We also knocked down MEF2C expression in cord blood-derived haematopoietic stem cells by siRNA. We found that absent or reduced MEF2C expression resulted in defects in megakaryocytic differentiation and reduced levels of the candidate target genes. Luciferase assays confirmed that genomic sequences within the target genes are regulated by MEF2C levels. Finally, we demonstrate that small deletions linked to a platelet count-associated single nucleotide polymorphism alter transcriptional activity, suggesting a mechanism by which genetic variation in MEF2C alters platelet production. These data help elucidate the mechanism behind MEF2C regulation of megakaryopoiesis and genetic variation driving platelet production.


Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Yang Li ◽  
Bo Lin ◽  
Lei Yang

Introduction: Dissecting the gene expression programs which control the early stage cardiovascular development is essential for understanding the molecular mechanisms of human heart development and heart disease. Many lineage-specific genes are involved in the differentiation into specific cell fate. Hypothesis: The lineage-specificity of the genes may predict regulatory potential during human cardiovascular differentiation. Methods: Here, we performed transcriptome sequencing (RNA-seq) of highly purified human Embryonic Stem Cells (hESCs), hESC-derived Multipotential Cardiovascular Progenitors (MCPs) and MCP-specified three cardiovascular lineages. A novel algorithm, named as Gene Expression Pattern Analyzer (GEPA), was developed to obtain a refined lineage-specificity map of all sequenced genes, which reveals dynamic changes of transcriptional factor networks underlying early human cardiovascular development. Results: The GEPA predictions captured ∼90% of top-ranked regulatory cardiac genes that were previously predicted based on chromatin signature changes in hESCs, and further defined their cardiovascular lineage-specificities, indicating that our multi-fate comparison analysis could predict novel regulatory genes. Furthermore, GEPA analysis revealed the MCP-specific expressions of genes in ephrin signaling pathway, positive role of which in cardiomyocyte differentiation was further validated experimentally. By using RNA-seq plus GEPA workflow, we also identified stage-specific RNA splicing switch and lineage-enriched long noncoding RNAs during human cardiovascular differentiation. Conclusions: Overall, our study utilized multi-cell-fate transcriptomic comparison analysis to establish a lineage-specific gene expression map for predicting and validating novel regulatory mechanisms underlying early human cardiovascular development.


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