Project description:The intermediate filament protein Nestin serves as a biomarker for stem cells and has been used to identify subsets of cancer stem-like cells. However, the mechanistic contributions of Nestin to cancer pathogenesis are not understood. Here we report that Nestin binds the hedgehog pathway transcription factor Gli3 to mediate the development of medulloblastomas of the hedgehog subtype. In a mouse model system, Nestin levels increased progressively during medulloblastoma formation resulting in enhanced tumor growth. Conversely, loss of Nestin dramatically inhibited proliferation and promoted differentiation. Mechanistic investigations revealed that the tumor-promoting effects of Nestin were mediated by binding to Gli3, a zinc finger transcription factor that negatively regulates hedgehog signaling. Nestin binding to Gli3 blocked Gli3 phosphorylation and its subsequent proteolytic processing, thereby abrogating its ability to negatively regulate the hedgehog pathway. Our findings show how Nestin drives hedgehog pathway-driven cancers and uncover in Gli3 a therapeutic target to treat these malignancies. Nestin+ and Nestin- GNPs (granule neuron precursors) were purified from Nestin-CFP/Math1-Cre/Ptch1-loxp cerebella at postnatal day 4 by FACs, and total RNA from these two cell populations were extracted, and then labeled and hybridized to Affymetrix Mouse Genome 430 2.0 arrays.
Project description:Engineered gold nanoparticles (GNPs) have become a useful tool in various therapeutic and diagnostic applications. Uncertainty remains regarding possible impacts of GNPs to the immune system. In this regard, we investigated the interactions of polymer-coated GNPs with B cells and their functions in mice as they constitute a crucial part of the immune system and represent a potential target for systemically administered GNPs. Surprisingly, we observed that polymer-coated GNPs mainly interact with the recently identified subpopulation of B lymphocytes named Age-associated B cells (ABCs). Importantly, we also showed that GNPs did not affect the percentages of other B cell populations in different organs. Furthermore, GNPs did not activate B cell innate-like immune responses in any of the tested conditions, nor did they impair adaptive B cell responses in immunized mice. Together, these data provide an important contribution to otherwise limited knowledge about GNP interference with B cell immune function, and demonstrate that GNPs represent a safe tool to target ABCs in vivo for various potential applications.
Project description:Sonic hedgehog (Shh) signals via Gli transcription factors to stimulate proliferation of granule neuron precursor cells (GNPs) in the cerebellum. Deregulation of Shh target genes often results in unrestrained GNP proliferation and eventually medulloblastoma (MB), the most common pediatric brain malignancy. Gene expression profiling was coupled with transcription factor binding location analysis to determine the Gli1-controlled transcriptional regulatory networks in GNPs and medulloblastoma cells. We detected significant overlap, as well as differences, in the Gli1-controlled transcriptional regulatory networks in GNPs and MBs. We determined the presence of gene expression in each dataset. There were 9260 genes expressed in Gli1-FLAG GNPs and 9185 genes expressed in Gli1-FLAG;Ptc+/- tumors; 8691 of which are in common. The large overlap is consistent with the cellular origin of these tumors. When the genes detectably expressed were intersected with our binding data, there were only 132 putative Gli1 target genes shared by both cell populations. Due to the heightened activation of the Hh pathway in tumors relative to GNPs, we further deduced direct Gli1 target genes exclusive to tumors by determining significantly induced genes in tumors versus in Ptc+/- GNPs. We identified at least 116 tumor-specific Gli1 target genes. These data suggest that tumor formation is accompanied by a tremendous change in the battery of Gli target genes. Presence of gene expression was determined for all samples: Gli1-FLAG-expressing GNPs, Ptc+/- GNPs, and Gli1-FLAG;Ptc+/-medulloblastomas. These datasets were intersected with chIP-chip data to determine potential direct Gli1 target genes. Differential gene expression was determined by comparing expression profiles from medulloblastoma tumors to those from Ptc+/- GNPs.
Project description:The morphogen and mitogen, Sonic Hedgehog, activates a Gli1-dependent transcription program that drives proliferation of granule neuron progenitors (GNPs) within the external germinal layer of the postnatally developing cerebellum. Medulloblastomas with mutations activating the Sonic Hedgehog signaling pathway preferentially arise within the external germinal layer, and the tumor cells closely resemble GNPs. Atoh1/Math1, a basic helix-loop-helix transcription factor essential for GNP histogenesis, does not induce medulloblastomas when expressed in primary mouse GNPs that are explanted from the early postnatal cerebellum and transplanted back into the brains of naïve mice. However, enforced expression of Atoh1 in primary GNPs enhances the oncogenicity of cells overexpressing Gli1 by almost three orders of magnitude. Unlike Gli1, Atoh1 cannot support GNP proliferation in the absence of Sonic Hedgehog signaling and does not govern expression of canonical cell cycle genes. Instead, Atoh1 maintains GNPs in a Sonic Hedgehog-responsive state by regulating genes that trigger neuronal differentiation, including many expressed in response to bone morphogenic protein-4. Therefore, by targeting multiple genes regulating the differentiation state of GNPs, Atoh1 collaborates with the pro-proliferative Gli1-dependent transcriptional program to influence medulloblastoma development. Keywords: disease state analysis
Project description:The morphogen and mitogen, Sonic Hedgehog, activates a Gli1-dependent transcription program that drives proliferation of granule neuron progenitors (GNPs) within the external germinal layer of the postnatally developing cerebellum. Medulloblastomas with mutations activating the Sonic Hedgehog signaling pathway preferentially arise within the external germinal layer, and the tumor cells closely resemble GNPs. Atoh1/Math1, a basic helix-loop-helix transcription factor essential for GNP histogenesis, does not induce medulloblastomas when expressed in primary mouse GNPs that are explanted from the early postnatal cerebellum and transplanted back into the brains of naïve mice. However, enforced expression of Atoh1 in primary GNPs enhances the oncogenicity of cells overexpressing Gli1 by almost three orders of magnitude. Unlike Gli1, Atoh1 cannot support GNP proliferation in the absence of Sonic Hedgehog signaling and does not govern expression of canonical cell cycle genes. Instead, Atoh1 maintains GNPs in a Sonic Hedgehog-responsive state by regulating genes that trigger neuronal differentiation, including many expressed in response to bone morphogenic protein-4. Therefore, by targeting multiple genes regulating the differentiation state of GNPs, Atoh1 collaborates with the pro-proliferative Gli1-dependent transcriptional program to influence medulloblastoma development. Keywords: disease state analysis 14 samples, 1 time series, 2 engineered Medulloblastoma tumors
Project description:Molecular networking has become a key method to visualize and annotate the chemical space in non-targeted mass spectrometry data. We present feature-based molecular networking (FBMN) as an analysis method in the Global Natural Products Social Molecular Networking (GNPS) infrastructure that builds on chromatographic feature detection and alignment tools. FBMN enables quantitative analysis and resolution of isomers, including from ion mobility spectrometry.
Project description:Sonic hedgehog (Shh) signals via Gli transcription factors to stimulate proliferation of granule neuron precursor cells (GNPs) in the cerebellum. Deregulation of Shh target genes often results in unrestrained GNP proliferation and eventually medulloblastoma (MB), the most common pediatric brain malignancy. Gene expression profiling was coupled with transcription factor binding location analysis to determine the Gli1-controlled transcriptional regulatory networks in GNPs and medulloblastoma cells. We detected significant overlap, as well as differences, in the Gli1-controlled transcriptional regulatory networks in GNPs and MBs. We determined the presence of gene expression in each dataset. There were 9260 genes expressed in Gli1-FLAG GNPs and 9185 genes expressed in Gli1-FLAG;Ptc+/- tumors; 8691 of which are in common. The large overlap is consistent with the cellular origin of these tumors. When the genes detectably expressed were intersected with our binding data, there were only 132 putative Gli1 target genes shared by both cell populations. Due to the heightened activation of the Hh pathway in tumors relative to GNPs, we further deduced direct Gli1 target genes exclusive to tumors by determining significantly induced genes in tumors versus in Ptc+/- GNPs. We identified at least 116 tumor-specific Gli1 target genes. These data suggest that tumor formation is accompanied by a tremendous change in the battery of Gli target genes.