Project description:Glioblastoma (GBM) is thought to be driven by a sub-population of cancer stem cells (CSCs) that self-renew and recapitulate tumor heterogeneity, yet remain poorly understood. Here we present a comparative epigenomic analysis of GBM CSCs that reveals widespread activation of genes normally held in check by Polycomb repressors. These activated targets include a large set of developmental transcription factors (TFs) whose coordinated activation is unique to the CSCs. We demonstrate that a critical factor in the set, ASCL1, activates Wnt signaling by repressing the negative regulator DKK1. We show that ASCL1 is essential for maintenance and in vivo tumorigenicity of GBM CSCs. Genomewide binding profiles for ASCL1 and the Wnt effector LEF1 provide mechanistic insight and suggest widespread interactions between the TF module and the signaling pathway. Our findings demonstrate regulatory connections between ASCL1, Wnt signaling and collaborating TFs that are essential for the maintenance and tumorigenicity of GBM CSCs. Two replicates for MGG4, MGG6, MGG23 and NS; four replicates for MGG8
Project description:Glioblastoma (GBM) is thought to be driven by a sub-population of cancer stem cells (CSCs) that self-renew and recapitulate tumor heterogeneity, yet remain poorly understood. Here we present a comparative epigenomic analysis of GBM CSCs that reveals widespread activation of genes normally held in check by Polycomb repressors. These activated targets include a large set of developmental transcription factors (TFs) whose coordinated activation is unique to the CSCs. We demonstrate that a critical factor in the set, ASCL1, activates Wnt signaling by repressing the negative regulator DKK1. We show that ASCL1 is essential for maintenance and in vivo tumorigenicity of GBM CSCs. Genomewide binding profiles for ASCL1 and the Wnt effector LEF1 provide mechanistic insight and suggest widespread interactions between the TF module and the signaling pathway. Our findings demonstrate regulatory connections between ASCL1, Wnt signaling and collaborating TFs that are essential for the maintenance and tumorigenicity of GBM CSCs. Epigenomic profiling of glioblastoma stem cells
Project description:Glioblastoma (GBM) is thought to be driven by a sub-population of cancer stem cells (CSCs) that self-renew and recapitulate tumor heterogeneity, yet remain poorly understood. Here we present a comparative epigenomic analysis of GBM CSCs that reveals widespread activation of genes normally held in check by Polycomb repressors. These activated targets include a large set of developmental transcription factors (TFs) whose coordinated activation is unique to the CSCs. We demonstrate that a critical factor in the set, ASCL1, activates Wnt signaling by repressing the negative regulator DKK1. We show that ASCL1 is essential for maintenance and in vivo tumorigenicity of GBM CSCs. Genomewide binding profiles for ASCL1 and the Wnt effector LEF1 provide mechanistic insight and suggest widespread interactions between the TF module and the signaling pathway. Our findings demonstrate regulatory connections between ASCL1, Wnt signaling and collaborating TFs that are essential for the maintenance and tumorigenicity of GBM CSCs. Histone modification profiling for multiple marks by ChIP-Seq in untreated glioblastoma cancer stem cells, glioblastoma non-stem cells and neural stem cells
Project description:The complex system by which the skin regulates immune responses to the external environment is unclear. Here, we investigated cell-cell interactions underlying cutaneous defense against S. aureus. Single-cell transcriptomics (scRNA-Seq) and unbiased network analysis revealed unexpected, dominant IL-17-mediated dermal reticular fibroblast-to-neutrophil communication. Multi-faceted in vitro omics studies demonstrated that IL-17 synergized with several factors including TNF⍺ to induce fibroblast NFKBIZ and chemokine secretion. Cultured fibroblasts drove robust neutrophil recruitment through NFKBIZ-dependent CXCR2 and CXCR4 ligands. Mice lacking IL-17R in fibroblasts (PdgfraΔIl17ra) were generated to determine the significance of fibroblast-neutrophil communication. PdgfraΔIl17ra mice exhibited drastically reduced skin neutrophilia in multiple disease models and reduced defense against S. aureus. These findings were translated to humans by comprehensive analysis of biopsies from psoriasis patients on and off anti-IL-17 treatment. Thus, dermal fibroblasts are critical for skin type 17 inflammation and represent a novel target for treatment of infection and inflammatory disease.
Project description:The complex system by which the skin regulates immune responses to the external environment is unclear. Here, we investigated cell-cell interactions underlying cutaneous defense against S. aureus. Single-cell transcriptomics (scRNA-Seq) and unbiased network analysis revealed unexpected, dominant IL-17-mediated dermal reticular fibroblast-to-neutrophil communication. Multi-faceted in vitro omics studies demonstrated that IL-17 synergized with several factors including TNF⍺ to induce fibroblast NFKBIZ and chemokine secretion. Cultured fibroblasts drove robust neutrophil recruitment through NFKBIZ-dependent CXCR2 and CXCR4 ligands. Mice lacking IL-17R in fibroblasts (PdgfraΔIl17ra) were generated to determine the significance of fibroblast-neutrophil communication. PdgfraΔIl17ra mice exhibited drastically reduced skin neutrophilia in multiple disease models and reduced defense against S. aureus. These findings were translated to humans by comprehensive analysis of biopsies from psoriasis patients on and off anti-IL-17 treatment. Thus, dermal fibroblasts are critical for skin type 17 inflammation and represent a novel target for treatment of infection and inflammatory disease.
Project description:The hair follicle (HF) is a complex miniorgan that serves as an ideal model system to study stem cell (SC) interactions with the niche during growth and regeneration. Dermal papilla (DP) cells are required for activating SCs during the adult hair cycle, but the signal exchange between niche and SC precursors/transit amplifying progenitor cells (TACs) that regulates HF morphogenetic growth is largely unknown. Here we use six transgenic reporters to isolate 14 major skin and HF cell populations. With next-generation RNA sequencing we characterize their transcriptomes and define unique molecular signatures. SC precursors, TACs and the DP niche express a plethora of known and novel ligands and receptors. Signaling interaction network analysis reveals a birds-eye view of pathways implicated in epithelial-mesenchymal interactions. Using a systematic tissue-wide approach this work provides a comprehensive platform, linked to an interactive online database, to identify and further explore the SC/TAC/niche crosstalk regulating HF growth.
Project description:The transition to flowering in plants is controlled by a regulatory network that responds to both developmental and environmental signals. The MADS-box genes FLOWERING LOCUS C (FLC) and SHORT VEGETATIVE PHASE (SVP) are major flowering repressors that enhance responses to environmental cues such as winter temperatures, high ambient temperatures and photoperiod. FLC and SVP physically interact in vivo and mutation of each gene causes early flowering while the double mutant is more extreme. The molecular mechanisms underlying these genetic interactions are mostly unknown. We addressed the regulatory input of these two key transcription factors (TFs) both individually and as a complex at the genome-wide level through ChIP-seq and microarray expression analysis in single and double mutants. Analysis of each TF demonstrated that the complex acts predominantly via functional redundancy in the repression of flowering. SVP and FLC bind to the same regions of the flowering genes SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1) and FLOWERING LOCUS T (FT) but do not require the presence of the other to bind. However, genome-wide identification of SVP and FLC occupancy events revealed that their binding scenarios are quantitatively and qualitatively affected by the presence of the cognate partner. A subgroup of genes whose regulation by these TFs depends exclusively on combinatorial binding of both proteins was identified, demonstrating a qualitatively essential role of the SVP-FLC complex. Some of these genes are involved in the control of flowering through direct and indirect regulation of Gibberellin-related processes. Cis-regulatory elements enriched only at such complex-bound sites were identified. Thus the regulatory output mediated by SVP and FLC reveals substantial flexibility, leading to dependent and independent DNA binding that enables additive, cooperative and repressive modes of co-regulation. In total 48 samples; 24 leaf samples corresponding to two different growing conditions, 24 apex samples corresponding to two different growing conditions.