Oct4-mediated inhibition of Lsd1 activity promotes the active and primed state of pluripotency enhancers [ChIP-seq]
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ABSTRACT: Enhancer reactivation and pluripotency gene (PpG) expression could induce stemness and enhance tumorigenicity in cancer stem cells. Silencing of PpG enhancers (PpGe) during embryonic stem cell differentiation involves Lsd1–mediated H3K4me1 demethylation followed by DNA methylation. Here, we observed a widespread retention of H3K4me1 and DNA hypomethylation at PpGe associated with a partial repression of PpGs in F9 embryonal carcinoma cells (ECCs) post-differentiation. The absence of H3K4me1 demethylation could not be rescued by Lsd1 overexpression. Based on the observation that H3K4me1 demethylation is accompanied by strong Oct4 repression in P19 ECCs, we tested if Lsd1-Oct4 interaction affects Lsd1 catalytic activity. Our data show a dose-dependent inhibition of Lsd1 by Oct4 in vitro and retention of H3K4me1 at PpGe post-differentiation in Oct4 overexpressing P19 ECCs. These data suggest that Lsd1-Oct4 interaction in cancer stem cells may establish a primed enhancer state that is susceptible to reactivation leading to aberrant PpG expression.
Project description:Enhancer reactivation and pluripotency gene (PpG) expression could induce stemness and enhance tumorigenicity in cancer stem cells. Silencing of PpG enhancers (PpGe) during embryonic stem cell differentiation involves Lsd1–mediated H3K4me1 demethylation followed by DNA methylation. Here, we observed a widespread retention of H3K4me1 and DNA hypomethylation at PpGe associated with a partial repression of PpGs in F9 embryonal carcinoma cells (ECCs) post-differentiation. The absence of H3K4me1 demethylation could not be rescued by Lsd1 overexpression. Based on the observation that H3K4me1 demethylation is accompanied by strong Oct4 repression in P19 ECCs, we tested if Lsd1-Oct4 interaction affects Lsd1 catalytic activity. Our data show a dose-dependent inhibition of Lsd1 by Oct4 in vitro and retention of H3K4me1 at PpGe post-differentiation in Oct4 overexpressing P19 ECCs. These data suggest that Lsd1-Oct4 interaction in cancer stem cells may establish a primed enhancer state that is susceptible to reactivation leading to aberrant PpG expression.
Project description:Differential DNA methylation is characteristic of gene regulatory regions, such as enhancers, which mostly constitute low or intermediate CpG content in their DNA sequence. Consequently, quantification of changes in DNA methylation at these sites is challenging. Given DNA methylation across most of the mammalian genome is maintained, use of genome-wide bisulfite sequencing to measure fractional changes in DNA methylation at specific sites is an overexertion which is both expensive and cumbersome. Here we developed a MethylRAD technique with an improved experimental plan and bioinformatic analysis tool to examine regional DNA methylation changes in embryonic stem cells (ESCs) during differentiation. The transcriptional silencing of pluripotency genes (PpGs) during ESC differentiation is accompanied by PpG enhancer (PpGe) silencing mediated by demethylation of H3K4me1 by LSD1. Our MethylRAD data show that in presence of LSD1 inhibitor, a significant fraction of LSD1-bound PpGe fails to gain DNA methylation. We further show that this effect is mostly observed at PpGe with low/intermediate CpG content. Underscoring the sensitivity and accuracy of MethylRAD sequencing, our study demonstrates that this method can detect small changes in DNA methylation at regulatory regions including with low/intermediate CpG content, thus asserting it use as a method of choice for diagnostic purpose.
Project description:To understand the role of LSD1 in regulating histone H3K4 methylation status, ChIP-seq analyse of mono- and di-methylated H3K4 in LSD1-KD HEL cells were performed. The analyses revealed demethylation of H3K4me1 and H3K4me2 by LSD1 at regulatory regions including CEBPA gene enhancer.
Project description:By screening a collection of epigenetic compounds, we find that Lysine-Specific Demethylase 1 (LSD1) inhibitors repress brown adipocyte differentiation. RNAi-mediated Lsd1 knockdown shows similar effect, which can be rescued by expression of wild-type, but not catalytically inactive, LSD1. Furthermore, adenoviral Cre-mediated LSD1 deletion in mice leads to inhibition of brown adipogenesis, validating the pivotal role of LSD1 in brown fat development in vivo. LSD1 is a histone H3 demethylase, which selectively removes methyl groups from mono- and di-methylated lysine 4 (H3K4me1 and H3K4me2) under most circumstances, and only from lysine 9 (H3K9me1/2) when bound with androgen receptor (AR) or estrogen receptor (ER). K4 demethylation causes transcription repression, while K9 demethylation may lead to activation of gene transcription. To investigate the target genes of LSD1 during BAT differentiaiton, we performed RNA-seq to profile the gene expression in brown adipocytes treated with DMSO or LSD1 inhibitor 611 (Cpd A) for 6 days, and gene set enrichment analysis (GSEA) was then employed to identify Gene Ontology (GO) terms that were significantly enriched.
Project description:Here we describe that lysine-specific demethylase 1 (Lsd1/KDM1a), which demethylates histone H3 on LysM-bM-^@M-^I4 or LysM-bM-^@M-^I9 (H3K4/K9), is an indispensible epigenetic governor of hematopoietic differentiation. Integrative genomic analysis in primary hematopoietic cells, combining global occupancy of Lsd1, genome-wide analysis of its histone substrates H3K4 mono- and di-methylation and gene expression profiling, reveals that Lsd1 represses hematopoietic stem and progenitor cell (HSPC) gene expression programs during hematopoietic differentiation. We found that Lsd1 function was not restricted to transcription start sites, but is also critical at enhancers. Loss of Lsd1 at these sites was associated with increased H3K4me1 and H3K4me2 methylation levels on HSPC genes and their derepression. Failure to fully silence HSPC genes compromised differentiation of hematopoietic stem cells and mature blood cell lineages. Our data indicate that Lsd1-mediated concurrent repression of enhancer and promoter activity of stem and progenitor cell genes is a pivotal epigenetic mechanism required for proper hematopoietic maturation. To identify direct target genes of Lsd1 in myeloid cells we mapped global occupancy of Lsd1 in 32D granuolocytic progenitor cells and compared H3K4me1/me2/me3 and H3K27ac histone modifications in Lsd1fl/fl (wild type) vs. Lsd1fl/f Mx1Cre (knockout) Gr1dim Mac1 granuolocytic progenitor cells.
Project description:Lysine Specific Demethylase 1 (LSD1, KDM1A) functions as a transcriptional corepressor through demethylation of histone 3 lysine 4 (H3K4), but has coactivator function on some genes through unclear mechanisms. We show that LSD1, interacting with CoREST, associates with and coactivates androgen receptor (AR) on a large fraction of androgen-stimulated genes. A subset of these AR/LSD1-associated enhancer sites have histone 3 threonine 6 phosphorylation (H3T6ph), and these sites are further enriched for androgen-stimulated genes. Significantly, despite its coactivator activity, LSD1 still mediates H3K4me2 demethylation at these androgen-stimulated enhancers. FOXA1 is also associated with LSD1 at AR regulated enhancer sites, and a FOXA1 interaction with LSD1 enhances binding of both proteins at these sites. These findings show LSD1 functions broadly as a regulator of AR function, that it maintains a transcriptional repression function at AR-regulated enhancers through H3K4 demethylation, and has a distinct AR-linked coactivator function mediated by demethylation of other substrates. Determine the role of LSD1 in androgen signaling.
Project description:Lysine-specific histone demethylase 1 (LSD1), which demethylates mono- or di- methylated histone H3 on lysine 4 (H3K4me1/2), is essential for early embryogenesis and development. Here we show that LSD1 is dispensable for embryonic stem cell (ESC) self-renewal but is required for ESC growth and differentiation. Reexpression of a catalytically-dead LSD1 (LSD1MUT) recovers the proliferation capability of ESCs, yet the enzymatic activity of LSD1 is essential to ensure proper differentiation. Indeed, a gain of H3K4me1 in Lsd1 knockout (KO) ESCs does not lead to major changes in global gene expression programs related to stemness. However, ablation of LSD1 but not LSD1MUT results in decreased DNMT1 and UHRF1 proteins coupled to global hypomethylation. We show that both LSD1 and LSD1MUT control protein stability of UHRF1 and DNMT1 through interaction with the ubiquitin-specific peptidase 7 (USP7) and, consequently, inhibiting DNMT1 and UHRF1 ubiquitylation. Our studies elucidate for the first time a novel mechanism by which the scaffolding function of LSD1 controls DNA methylation in ESCs.
Project description:Transcription factors and chromatin modifiers play important roles in programming and reprogramming of cellular states during development. Much is known about the role of these regulators in gene activation, but relatively little is known about the critical process of enhancer silencing during differentiation. Here we show that the H3K4/K9 histone demethylase LSD1 plays an essential role in decommissioning enhancers during differentiation of embryonic stem cells (ESCs). LSD1 occupies enhancers of active genes critical for control of ESC state. However, LSD1 is not essential for maintenance of ESC identity. Instead, ESCs lacking LSD1 activity fail to fully differentiate and ESC-specific enhancers fail to undergo the histone demethylation events associated with differentiation. At enhancers, LSD1 is a component of the NuRD complex, which contains additional subunits that are necessary for ESC differentiation. We propose that the LSD1-NuRD complex decommissions enhancers of the pluripotency program upon differentiation, which is essential for complete shutdown of the ESC gene expression program and the transition to new cell states. This represents the expression part of the study.
Project description:Transcription factors and chromatin modifiers play important roles in programming and reprogramming of cellular states during development. Much is known about the role of these regulators in gene activation, but relatively little is known about the critical process of enhancer silencing during differentiation. Here we show that the H3K4/K9 histone demethylase LSD1 plays an essential role in decommissioning enhancers during differentiation of embryonic stem cells (ESCs). LSD1 occupies enhancers of active genes critical for control of ESC state. However, LSD1 is not essential for maintenance of ESC identity. Instead, ESCs lacking LSD1 activity fail to fully differentiate and ESC-specific enhancers fail to undergo the histone demethylation events associated with differentiation. At enhancers, LSD1 is a component of the NuRD complex, which contains additional subunits that are necessary for ESC differentiation. We propose that the LSD1-NuRD complex decommissions enhancers of the pluripotency program upon differentiation, which is essential for complete shutdown of the ESC gene expression program and the transition to new cell states. This is the ChIP-seq part of the study.
Project description:Profiling of H3K4me1 genome wide occupancy in mESC WT, LSD1 KO, and rescued with WT LSD1 (RO) and with mutant LSD1 (AK) to explore the effects of LSD1 on histone methylation.