Project description:Single-cell RNA datasets for aortic tissue from 8-week-old inducible smooth muscle cell-specific knock-in of Acta2 R179C mutation vs. littermate controls and aortic aneurysm tissue from a human patient carrying an ACTA2 R179H variant vs. a pediatric organ donor healthy control.
Project description:Human diffuse intrinsic pontine gliomas (DIPG) are an aggressive form of pediatric brain tumors that arise in the pons in young children thus resulting in significant morbidity and very poor survival. Recent data suggest that mutations in the histone H3.3 variant are often found in these tumors, though the mechanism of their contribution to oncogenesis remains to be elucidated. Here we report that the combination of constitutive PDGFRA activation and p53 suppression as well as expression of the K27M mutant form of the histone H3.3 variant leads to neoplastic transformation of hPSC-derived neural precursors. Our study demonstrates that human ES cells represent an excellent platform for the modeling of human tumors in vitro and in vivo, which could potentially lead to the elucidation of the molecular mechanisms underlying neoplastic transformation and the identification of novel therapeutic targets. Human ES cells were differentiated to NPCs and lentivirally transduced with a combination of constitutively active PDGFRA (D842V), sh-p53, and WT or K27M mutant form of histone H3.3 variant.
Project description:Recent studies have identified a Lys 27-to-methionine (K27M) mutation at one allele of H3F3A, one of the two genes encoding histone H3 variant H3.3, in 60% of high-grade pediatric glioma cases. The median survival of this group of patients after diagnosis is ∼1 yr. Here we show that the levels of H3K27 di- and trimethylation (H3K27me2 and H3K27me3) are reduced globally in H3.3K27M patient samples due to the expression of the H3.3K27M mutant allele. Remarkably, we also observed that H3K27me3 and Ezh2 (the catalytic subunit of H3K27 methyltransferase) at chromatin are dramatically increased locally at hundreds of gene loci in H3.3K27M patient cells. Moreover, the gain of H3K27me3 and Ezh2 at gene promoters alters the expression of genes that are associated with various cancer pathways. These results indicate that H3.3K27M mutation reprograms epigenetic landscape and gene expression, which may drive tumorigenesis. We performed chromatin-immunoprecipitation of H3K27me3, H3K4me3, and EZH2 in SF7761 and NSC cell lines. And do RNA-seq in SF7761, SF8828 and NSC cell lines. SF7761 and SF8628 cell lines from patients harboring the histone H3.3 K27M mutation were obtained from Hashizume et al. (2012). NSCs (N7800-100) were purchased from Invitrogen and cultured and maintained in NSC medium (A10509-01, StemPro NSC SFM, Invitrogen).
Project description:Pediatric high-grade gliomas (pHGGs) harboring the K27M mutation of H3F3A (histone H3.3) are characterized by global reduction of the repressive histone mark H3K27me3 and DNA hypomethylation. Analysis of K27M-induced changes on H3K27me3 occupancy and DNA methylation at differentially expresed genes (K27M vs. wild-type H3.3) in primary pHGG tumor samples. 22 glioblastoma samples from pHGG patients were selected for RNA extraction and hybridization on Affymetrix Affymetrix Human Genome U133 Plus 2.0 Arrays. Expression profiling data of 17 pHHGs are part of our previous study (GSE36245 or GSE34824).
Project description:Study to investigate the role of histone residues H3K4 and H3K36 for gene expression, histone localization and neuronal lineage specification by mutation of K4 and K36 in H3.3 to alanine. Histone variant H3.3 differs from the canonical H3.1/H3.2 by only 4 to 5 amino acids, which are necessary for nucleosome assembly independent of DNA replication, and is encoded by two gene copies. Complete loss of the two H3.3 genes (H3f3a and H3f3b) leads to embryonic lethality while single gene knockout yields viable mice. We used CRISPR-Cas9 to delete H3f3a and introduce homozygous point-mutations into H3f3b, thus ensuring that the entire pool of H3.3 protein carries the mutation of interest. We differentiated H3.3ctrl (H3f3a knock-out; H3f3b wild type), H3.3K4A mutant (H3f3a knock-out; H3f3b K4A) and H3.3K36A mutant (H3f3a knock-out; H3f3b K36A) ESCs into glutamatergic neurons. Genomic localization of H3.3 protein was determined by ChIP-Sequencing in ESCs (D0). Histone modifications patterns of H3K4me1, H3K4me3 and H3K27ac were measured by ChIP-Sequencing in ESCs (D0) to assess the impact of the H3.3K4A mutation on the epigenetic landscape. Levels of H3K36me3 were measured by ChIP-Sequencing in WT and H3.3K36A mutant ESCs (D0), NPCs (D8) and neurons (D12) to assess the impact of the H3.3K36A mutation on H3K36me3 levels in development.
Project description:Lysine 27 to methionine mutation (H3K27M) of the H3F3A gene, which encodes the variant histone H3.3, is found in the majority of Diffuse Intrinsic Pontine Gliomas (DIPGs). DIPGs are the most aggressive form of pediatric gliomas and have a median survival of <1 year from diagnosis. As H3K27M mutation is necessary but not sufficient to cause DIPGs, it is accompanied by several other mutations in tumors. However, the mechanisms by which H3K27M increases vulnerability to DIPG tumorigenesis, while expected to involve altered epigenetic regulation is unclear. Thus, in this work we built pairs of isogenic human embryonic stem cell lines with versus without this mutation, in the absence of other DIPG contributory mutations, to investigate mechanisms by which H3K27M mutation could affect cellular proliferation and differentiation and how these were related to alterations in the transcriptome, H3K27me3, and the DNA methylome. We found that H3K27M increased stem cell proliferation and interfered with differentiation, resulting in loss of most H3K27me3 and resulting in anomalous onset of expression of developmental genes during multilineage or directed differentiation. This work suggests mechanisms by which H3K27M mutation influences stem cell properties, contributing to DIPG tumorigenesis.
Project description:Lysine 27 to methionine mutation (H3K27M) of the H3F3A gene, which encodes the variant histone H3.3, is found in the majority of Diffuse Intrinsic Pontine Gliomas (DIPGs). DIPGs are the most aggressive form of pediatric gliomas and have a median survival of <1 year from diagnosis. As H3K27M mutation is necessary but not sufficient to cause DIPGs, it is accompanied by several other mutations in tumors. However, the mechanisms by which H3K27M increases vulnerability to DIPG tumorigenesis, while expected to involve altered epigenetic regulation is unclear. Thus, in this work we built pairs of isogenic human embryonic stem cell lines with versus without this mutation, in the absence of other DIPG contributory mutations, to investigate mechanisms by which H3K27M mutation could affect cellular proliferation and differentiation and how these were related to alterations in the transcriptome, H3K27me3, and the DNA methylome. We found that H3K27M increased stem cell proliferation and interfered with differentiation, resulting in loss of most H3K27me3 and resulting in anomalous onset of expression of developmental genes during multilineage or directed differentiation. This work suggests mechanisms by which H3K27M mutation influences stem cell properties, contributing to DIPG tumorigenesis.
Project description:Lysine 27 to methionine mutation (H3K27M) of the H3F3A gene, which encodes the variant histone H3.3, is found in the majority of Diffuse Intrinsic Pontine Gliomas (DIPGs). DIPGs are the most aggressive form of pediatric gliomas and have a median survival of <1 year from diagnosis. As H3K27M mutation is necessary but not sufficient to cause DIPGs, it is accompanied by several other mutations in tumors. However, the mechanisms by which H3K27M increases vulnerability to DIPG tumorigenesis, while expected to involve altered epigenetic regulation is unclear. Thus, in this work we built pairs of isogenic human embryonic stem cell lines with versus without this mutation, in the absence of other DIPG contributory mutations, to investigate mechanisms by which H3K27M mutation could affect cellular proliferation and differentiation and how these were related to alterations in the transcriptome, H3K27me3, and the DNA methylome. We found that H3K27M increased stem cell proliferation and interfered with differentiation, resulting in loss of most H3K27me3 and resulting in anomalous onset of expression of developmental genes during multilineage or directed differentiation. This work suggests mechanisms by which H3K27M mutation influences stem cell properties, contributing to DIPG tumorigenesis.