Project description:Several basic helix-loop-helix (bHLH) transcription factors are upregulated in Sonic Hedgehog subgroup of medulloblastoma (SHH MB). Olig2, a neural bHLH transcription factor known to regulate differentiation of neural cell populations, is broadly expressed in mouse models of SHH MB. ChIP-Seq of Olig2 revealed its binding to a large number of sites near genes known to promote SHH MB tumorigenesis, suggesting a potential role for Olig2 in regulating transcriptional programme of MB.
Project description:Origins of the brain tumor, medulloblastoma, from stem cells or restricted pro-genitor cells are unclear. To investigate this, we activated oncogenic Hedgehog signaling in multipotent and lineage-restricted CNS progenitors. We observed that normal unipo-tent cerebellar granule neuron precursors (CGNP) derive from hGFAP+ and Olig2+ rhombic lip progenitors. Hedgehog activation in a spectrum of early and late stage CNS progenitors generated similar medulloblastomas, but not other brain cancers, indicating that acquisition of CGNP identity is essential for tumorigenesis. We show in human and mouse medulloblastoma that cells expressing the glia-associated markers Gfap and Olig2 are neoplastic and that they retain features of embryonic-type granule lineage progenitors. Thus, oncogenic Hedgehog signaling promotes medulloblastoma from lineage-restricted granule cell progenitors. Gene expression profiling of cerebellar tumors generated from various early and late stage CNS progenitor cells. Experiment Overall Design: Group comparisons with biological replicates
Project description:Origins of the brain tumor, medulloblastoma, from stem cells or restricted pro-genitor cells are unclear. To investigate this, we activated oncogenic Hedgehog signaling in multipotent and lineage-restricted CNS progenitors. We observed that normal unipo-tent cerebellar granule neuron precursors (CGNP) derive from hGFAP+ and Olig2+ rhombic lip progenitors. Hedgehog activation in a spectrum of early and late stage CNS progenitors generated similar medulloblastomas, but not other brain cancers, indicating that acquisition of CGNP identity is essential for tumorigenesis. We show in human and mouse medulloblastoma that cells expressing the glia-associated markers Gfap and Olig2 are neoplastic and that they retain features of embryonic-type granule lineage progenitors. Thus, oncogenic Hedgehog signaling promotes medulloblastoma from lineage-restricted granule cell progenitors. Gene expression profiling of cerebellar tumors generated from various early and late stage CNS progenitor cells.
Project description:We show that a synthetic modified messenger RNA (smRNA)-based reprogramming method that leads to the generation of transgene-free OLs has been developed. An smRNA encoding a modified form of OLIG2, a key TF in OL development, in which the serine 147 phosphorylation site is replaced with alanine, OLIG2S147A, is designed to reprogram hiPSCs into OLs. We demonstrate that repeated administration of the smRNA encoding OLIG2 S147A lead to higher and more stable protein expression. Using the single-mutant OLIG2 smRNA morphogen, we establish a 6-day smRNA transfection protocol, and glial induction lead to rapid NG2+ OL progenitor cell (OPC) generation (> 70% purity) from hiPSC-derived neural progenitor cells (NPCs). The smRNA-induced NG2+ OPCs can mature into functional OLs in vitro and promote remyelination in vivo. Proteomic analysis of OLIG2-binding proteins indicates that OLIG2 is bound by the heat shock protein 70 (HSP70) complex. The HSP70 complex is bound more strongly to OLIG2 with the modified phosphorylation site than to wild-type OLIG2.
Project description:By utilizing single-cell analysis at different stages of tumorigenesis, we demonstrated a developmental hierarchy of dynamic progenitor pools in murine sonic hedgehog-(SHH) MBs. We identified Olig2+ progenitors as transit-amplifying cells during initial tumorigenic phases. These cells are quiescent stem-like progenitors in full-blown tumors but enriched in therapy-resistant as well as recurrent medulloblastomas. Olig2 ablation or depletion of mitotic Olig2+ progenitors abrogated tumorigenesis. Transcriptome profiling and chromatin occupancy assays revealed that Olig2 activates oncogenic networks including HIPPO- Yap/Taz signaling and Aurora-A/MycN pathways. Co-targeting these oncogenic pathways induced sustained tumor growth arrest. Together, our single-cell analyses uncover unexpected glia-lineage-related Olig2+ progenitor pools critical for medulloblastoma initiation and suggest targeting Olig2-regulated oncogenic pathways as an avenue for therapy.
Project description:By utilizing single-cell analysis at different stages of tumorigenesis, we demonstrated a developmental hierarchy of dynamic progenitor pools in murine sonic hedgehog-(SHH) MBs. We identified Olig2+ progenitors as transit-amplifying cells during initial tumorigenic phases. These cells are quiescent stem-like progenitors in full-blown tumors but enriched in therapy-resistant as well as recurrent medulloblastomas. Olig2 ablation or depletion of mitotic Olig2+ progenitors abrogated tumorigenesis. Transcriptome profiling and chromatin occupancy assays revealed that Olig2 activates oncogenic networks including HIPPO- Yap/Taz signaling and Aurora-A/MycN pathways. Co-targeting these oncogenic pathways induced sustained tumor growth arrest. Together, our single-cell analyses uncover unexpected glia-lineage-related Olig2+ progenitor pools critical for medulloblastoma initiation and suggest targeting Olig2-regulated oncogenic pathways as an avenue for therapy.
Project description:By utilizing single-cell analysis at different stages of tumorigenesis, we demonstrated a developmental hierarchy of dynamic progenitor pools in murine sonic hedgehog-(SHH) MBs. We identified Olig2+ progenitors as transit-amplifying cells during initial tumorigenic phases. These cells are quiescent stem-like progenitors in full-blown tumors but enriched in therapy-resistant as well as recurrent medulloblastomas. Olig2 ablation or depletion of mitotic Olig2+ progenitors abrogated tumorigenesis. Transcriptome profiling and chromatin occupancy assays revealed that Olig2 activates oncogenic networks including HIPPO- Yap/Taz signaling and Aurora-A/MycN pathways. Co-targeting these oncogenic pathways induced sustained tumor growth arrest. Together, our single-cell analyses uncover unexpected glia-lineage-related Olig2+ progenitor pools critical for medulloblastoma initiation and suggest targeting Olig2-regulated oncogenic pathways as an avenue for therapy.