Project description:Malignant gliomas constitute one of the most significant areas of unmet medical need, due to the invariable failure of surgical eradication and their marked molecular heterogeneity. Accumulating evidence has revealed a critical contribution by the Polycomb axis of epigenetic repression. However, a coherent understanding of the regulatory networks affected by Polycomb during gliomagenesis is still lacking. Here we integrate transcriptomic and epigenomic analyses to define Polycomb-dependent networks that promote gliomagenesis, validating them both in two independent mouse models and in a large cohort of human samples. We found that Polycomb dysregulation in gliomagenesis affects transcriptional networks associated to invasiveness and de-differentiation. The dissection of these networks uncovers Zfp423 as a crtitical Polycomb-dependent transcription factor whose silencing negatively impacts survival. The anti-gliomagenic activity of Zfp423 requires interaction with the SMAD proteins within the BMP signaling pathway, pointing to a novel synergic circuit through which Polycomb inhibits BMP signaling. Analysis of H3K27me3 distribition in two different stages of gliomagenesis
Project description:Malignant gliomas constitute one of the most significant areas of unmet medical need, due to the invariable failure of surgical eradication and their marked molecular heterogeneity. Accumulating evidence has revealed a critical contribution by the Polycomb axis of epigenetic repression. However, a coherent understanding of the regulatory networks affected by Polycomb during gliomagenesis is still lacking. Here we integrate transcriptomic and epigenomic analyses to define Polycomb-dependent networks that promote gliomagenesis, validating them both in two independent mouse models and in a large cohort of human samples. We found that Polycomb dysregulation in gliomagenesis affects transcriptional networks associated to invasiveness and de-differentiation. The dissection of these networks uncovers Zfp423 as a crtitical Polycomb-dependent transcription factor whose silencing negatively impacts survival. The anti-gliomagenic activity of Zfp423 requires interaction with the SMAD proteins within the BMP signaling pathway, pointing to a novel synergic circuit through which Polycomb inhibits BMP signaling. Transcriptomic analysis of two different stages of gliomagenesis
Project description:Malignant gliomas constitute one of the most significant areas of unmet medical need, due to the invariable failure of surgical eradication and their marked molecular heterogeneity. Accumulating evidence has revealed a critical contribution by the Polycomb axis of epigenetic repression. However, a coherent understanding of the regulatory networks affected by Polycomb during gliomagenesis is still lacking. Here we integrate transcriptomic and epigenomic analyses to define Polycomb-dependent networks that promote gliomagenesis, validating them both in two independent mouse models and in a large cohort of human samples. We found that Polycomb dysregulation in gliomagenesis affects transcriptional networks associated to invasiveness and de-differentiation. The dissection of these networks uncovers Zfp423 as a crtitical Polycomb-dependent transcription factor whose silencing negatively impacts survival. The anti-gliomagenic activity of Zfp423 requires interaction with the SMAD proteins within the BMP signaling pathway, pointing to a novel synergic circuit through which Polycomb inhibits BMP signaling.
Project description:Malignant gliomas constitute one of the most significant areas of unmet medical need, due to the invariable failure of surgical eradication and their marked molecular heterogeneity. Accumulating evidence has revealed a critical contribution by the Polycomb axis of epigenetic repression. However, a coherent understanding of the regulatory networks affected by Polycomb during gliomagenesis is still lacking. Here we integrate transcriptomic and epigenomic analyses to define Polycomb-dependent networks that promote gliomagenesis, validating them both in two independent mouse models and in a large cohort of human samples. We found that Polycomb dysregulation in gliomagenesis affects transcriptional networks associated to invasiveness and de-differentiation. The dissection of these networks uncovers Zfp423 as a crtitical Polycomb-dependent transcription factor whose silencing negatively impacts survival. The anti-gliomagenic activity of Zfp423 requires interaction with the SMAD proteins within the BMP signaling pathway, pointing to a novel synergic circuit through which Polycomb inhibits BMP signaling.
Project description:Cellular differentiation entails loss of pluripotency and parallel gain of lineage-specific and ultimately cell-type specific characteristics. Using a murine system that progresses from stem cells to lineage-committed progenitors and further to terminally differentiated neurons we analyzed two repressive epigenetic pathways: DNA methylation and Polycomb-mediated methylation of histone H3 (H3K27me3). We show that several hundred promoters become DNA methylated in lineage-committed progenitor cells. Targets are selected for pluripotency and germline-specific genes, suggesting a role for DNA methylation in stabilizing loss of pluripotency already at the progenitor state. Conversely, we detect loss and acquisition of H3K27me3 at novel targets at both progenitor and terminal state. Surprisingly, many neuron-specific genes that are poised to be activated upon terminal differentiation become Polycomb targets only in progenitor cells. Moreover, promoters marked by H3K27me3 in stem cells frequently become DNA methylated during differentiation, suggesting context-dependent crosstalk between Polycomb and DNA methylation. This data suggest a new model how de novo DNA methylation and dynamic switches in Polycomb targets restrict pluripotency and define the developmental potential of progenitor cells. Keywords: MeDIP-chip, ChIP-chip, neuronal differentiation time-course MeDIP-chip and ChIP-chip experiments were performed with at least two independnet biological replicates. For each condition hybridizations include a dye-swap experiment.
Project description:Cellular differentiation entails loss of pluripotency and parallel gain of lineage-specific and ultimately cell-type specific characteristics. Using a murine system that progresses from stem cells to lineage-committed progenitors and further to terminally differentiated neurons we analyzed two repressive epigenetic pathways: DNA methylation and Polycomb-mediated methylation of histone H3 (H3K27me3). We show that several hundred promoters become DNA methylated in lineage-committed progenitor cells. Targets are selected for pluripotency and germline-specific genes, suggesting a role for DNA methylation in stabilizing loss of pluripotency already at the progenitor state. Conversely, we detect loss and acquisition of H3K27me3 at novel targets at both progenitor and terminal state. Surprisingly, many neuron-specific genes that are poised to be activated upon terminal differentiation become Polycomb targets only in progenitor cells. Moreover, promoters marked by H3K27me3 in stem cells frequently become DNA methylated during differentiation, suggesting context-dependent crosstalk between Polycomb and DNA methylation. This data suggest a new model how de novo DNA methylation and dynamic switches in Polycomb targets restrict pluripotency and define the developmental potential of progenitor cells. Keywords: MeDIP-chip, ChIP-chip, neuronal differentiation time-course
Project description:Chromatin modifying activities for construction of appropriate epigenetic landscapes by polycomb repressive complex 2 (PRC2) play an essential role in development and tumorigenesis. However, the spatiotemporal mechanisms by which PRC2 achieves diverse epigenomes for specific tissue or cellular contexts remain poorly understood. Here, we discovered that LATS2 knockout causes dysregulation of PRC2 and subsequent transcriptome changes for differentiation in both mouse and human cells. LATS2 depletion dependent dysregulation of PRC2 also effects H3K4me3 and forms negative feedback loop for maintenance of PRC2. Further analyses reveal that LATS2 on chromatin binds to EZH2 and LATS2 has ability to phosphorylate PRC2 in vitro. These LATS2 dependent H3K27me3 targets are highly induced during neurogenesis, and statistical analysis of glioblastoma multiforme reveals that LATS2-high cases show more dedifferentiated transcriptome and poor prognosis with silencing of H3K27me3 targets. These observations suggest that LATS2-mediated epigenome coordination is pivotal for development and disease, including cancer. Three samples, two cell lines (WT_rep1, WT_rep2, and LATS2 KO) were analyzed by Agilent SurePrint G3 Human Gene Expression 8x60K v1 one color experiments.
Project description:Chromatin modifying activities for construction of appropriate epigenetic landscapes by polycomb repressive complex 2 (PRC2) play an essential role in development and tumorigenesis. However, the spatiotemporal mechanisms by which PRC2 achieves diverse epigenomes for specific tissue or cellular contexts remain poorly understood. Here, we discovered that LATS2 knockout causes dysregulation of PRC2 and subsequent transcriptome changes for differentiation in both mouse and human cells. LATS2 depletion dependent dysregulation of PRC2 also effects H3K4me3 and forms negative feedback loop for maintenance of PRC2. Further analyses reveal that LATS2 on chromatin binds to EZH2 and LATS2 has ability to phosphorylate PRC2 in vitro. These LATS2 dependent H3K27me3 targets are highly induced during neurogenesis, and statistical analysis of glioblastoma multiforme reveals that LATS2-high cases show more dedifferentiated transcriptome and poor prognosis with silencing of H3K27me3 targets. These observations suggest that LATS2-mediated epigenome coordination is pivotal for development and disease, including cancer. mRNA of wild type (WT) and LATS2 KO HeLa-S3 cells were subjected to deep sequencing profiling using Illumina HiSeq 2500