Huntington''s Disease (HD) is a fatal neurodegenerative disorder caused by an extended polyglutamine repeat in the N-terminus of the huntingtin (Htt) protein. Reactive microglia and elevated cytokine levels are observed in the brains of HD patients, but the extent to which neuroinflammation results from extrinsic or cell-autonomous mechanisms is unknown. Furthermore, the impact of microglia activation on the pathogenesis of HD remains to be established. Using genome-wide approaches, we show that expression of mutant Htt in microglia promotes cell-autonomous pro-inflammatory transcriptional activation within microglia by increasing the expression and transcriptional activities of the myeloid lineage-determining factors PU.1 and C/EBPs. Elevated levels of PU.1 and its target genes are observed in the brains of mouse models and HD individuals. Moreover, mutant Htt expressing microglia exhibit an increased capacity to induce neuronal death ex vivo and in vivo in the presence of sterile inflammation. These findings suggest that expression of mutant Htt in microglia may contribute to neuronal pathology in Huntingtin disease. Overall design: RNA-Seq and ChIP-Seq for PU.1, C/EBP, and H3K4me2 in BV2 cells and RNA-Seq in primary microglia and macrophages
Mutant Huntingtin promotes autonomous microglia activation via myeloid lineage-determining factors.
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View SamplesUbiquitous expression of ALS-causing mutations in superoxide dismutase 1 (SOD1) provoke non-cell autonomous paralytic disease. By combining ribosome affinity purification and high-throughput sequencing, a cascade of mutant SOD1-dependent, cell type-specific changes are now identified. Initial mutant-dependent damage is restricted to motor neurons and includes synapse and metabolic abnormalities, endoplasmic reticulum (ER) stress, and selective activation of the PERK arm of the unfolded protein response. PERK activation correlates with what we identify to be a naturally low level of ER chaperones in motor neurons. Early changes in astrocytes are to genes involved in inflammation and metabolism and that are targets of the PPAR and LXR transcription factors. Dysregulation of myelination and lipid signaling pathways and activation of ETS transcription factors occur in oligodendrocytes only after disease initiation. Thus, pathogenesis involves a temporal cascade of cell type selective damage initiating in motor neurons, with subsequent damage within glia driving disease propagation. Overall design: Cell type-specific mRNA was purified by ribosome affinity purification from the spinal cord of bacTRAP reporter mice that label selective cell types by EGFP-tagged ribosome RPL10A. Sequencing libraries were prepared from 3-6 biological replicates for each genotype to determine the mutant induced gene expression changes in specific cell types.
Translational profiling identifies a cascade of damage initiated in motor neurons and spreading to glia in mutant SOD1-mediated ALS.
Sex, Specimen part, Disease stage, Subject
View SamplesCross-linking and immunoprecipitation coupled with high-throughput sequencing was used to identify binding sites within 6,304 genes as the brain RNA targets for TDP-43, an RNA binding protein which when mutated causes Amyotrophic Lateral Sclerosis (ALS). Use of massively parallel sequencing and splicing-sensitive junction arrays revealed that levels of 601 mRNAs are changed (including Fus/Tls, progranulin, and other transcripts encoding neurodegenerative disease-associated proteins) and 965 altered splicing events are detected (including in sortilin, the receptor for progranulin), following depletion of TDP-43 from adult brain with antisense oligonucleotides. RNAs whose levels are most depleted by reduction in TDP-43 are derived from genes with very long introns and which encode proteins involved in synaptic activity. Lastly, TDP-43 was found to auto-regulate its synthesis, in part by directly binding and enhancing splicing of an intron within the 3’ untranslated region of its own transcript, thereby triggering nonsense mediated RNA degradation. Overall design: RNAseq in control and Tdp-43 knockdown mouse striatum
Long pre-mRNA depletion and RNA missplicing contribute to neuronal vulnerability from loss of TDP-43.
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View SamplesCross-linking and immunoprecipitation coupled with high-throughput sequencing was used to identify binding sites within 6,304 genes as the brain RNA targets for TDP-43, an RNA binding protein which when mutated causes Amyotrophic Lateral Sclerosis (ALS). Use of massively parallel sequencing and splicing-sensitive junction arrays revealed that levels of 601 mRNAs are changed (including Fus/Tls, progranulin, and other transcripts encoding neurodegenerative disease-associated proteins) and 965 altered splicing events are detected (including in sortilin, the receptor for progranulin), following depletion of TDP-43 from adult brain with antisense oligonucleotides. RNAs whose levels are most depleted by reduction in TDP-43 are derived from genes with very long introns and which encode proteins involved in synaptic activity. Lastly, TDP-43 was found to auto-regulate its synthesis, in part by directly binding and enhancing splicing of an intron within the 3’ untranslated region of its own transcript, thereby triggering nonsense mediated RNA degradation. Overall design: CLIP of Tdp-43 in 8 week mouse brain.
Long pre-mRNA depletion and RNA missplicing contribute to neuronal vulnerability from loss of TDP-43.
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View SamplesThrough the generation of humanized FUS mice expressing full length human FUS, we identify that when expressed at near endogenous murine FUS levels both wild-type or ALS- and frontotemporal dementia (FTD)-causing mutations complement the essential function(s) of murine FUS. Replacement of murine FUS with mutant, but not wild-type, human FUS causes stress-mediated induction of chaperones, decreased expression of ion channels/transporters essential for synaptic function, and reduced synaptic activity, without loss of nuclear FUS or its cytoplasmic aggregation. Most strikingly, accumulation of mutant human FUS is shown to activate an integrated stress response and inhibit local, intra-axonal protein synthesis in hippocampal neurons and sciatic nerves. Collectively, our evidence demonstrates that human ALS/FTD-linked mutations in FUS induce a gain-of-toxicity that includes stress-mediated suppression in intra-axonal translation, synaptic dysfunction, and progressive, age-dependent motor and cognitive disease without cytoplasmic aggregation, altered nuclear localization, or aberrant splicing of FUS-bound pre-mRNAs. Methods: RNA from mouse spinal cords of 18-month-old mFUS-/-/hgFUS (WT, R521C or R521H) and their Non-Tg control littermates was extracted with TRIzol. RNA quality was measured using the Agilent Bioanalyzer system and processed using the Illumina TruSeq Stranded mRNA Sample Preparation Kit according to manufacturer's protocols. mRNA profiles were generated by deep sequencing, with n=3 biological replicates per group. Results: We mapped on average 15 million non-redundant reads per sample. Fastq files were aligned to mouse reference genome (mm9 UCSC Genome Browser) using TopHat workfow and the transcript abundance for each annotated protein-coding gene [as fragments per kilobase of transcript per million mapped reads (FPKM)] was estimated by Cufflinks. 13,468 genes which expressed FPKM>=1 were kept for downstream analyses. RNA profiles from normal (Non-Tg) and humanized hgFUSWT mice were almost undistinguishable. Both humanized mutant FUS lines had highly distinct RNA profiles [determined with unsupervised hierarchical clustering and principal component analysis (PCA)], with 709 down and 348 up-regulated genes relative to age-matched Non-Tg or humanized hgFUSWT littermates (P<0.05). These changes uncovered FUS mutant dependent altered pathways that may contribute to ALS/FTD-linked mutant FUS-mediated toxicity. The validation by RT-QPCR of altered expression of 20 genes is shown in Figure 5. Overall design: RNA expression profile of mouse spinal cords from 18-month-old mFUS-/-/hgFUS (WT, R521C or R521H) and their Non-Tg control littermates was obtained by deep sequencing in n=3 indendepent animals per genotype using Illumina HiSeq 2000 sequencer.
ALS/FTD-Linked Mutation in FUS Suppresses Intra-axonal Protein Synthesis and Drives Disease Without Nuclear Loss-of-Function of FUS.
Age, Specimen part, Cell line, Subject
View SamplesPurpose: The purpose of this experiment is to identify a C9-ALS/FTD specific genomic profile in fibroblast lines that is distinct from sporadic ALS without C9orf72 expansion and non-neurologic control cells. The study will then evaluate the effect on this identified profile of ASO treatment targeting the sense strand RNA transcript of the C9orf72 gene. Methods: Expression profiling was performed on RNAs from fibroblasts of four C9orf72 patients, four control individuals and four sporadic ALS patients using Multiplex Analysis of PolyA-linked Sequences method. Results: Hierarchical clustering of expression values for all genes showed that the four C9orf72 patient lines had an expression profile distinct from control and sporadic ALS lines. Statistical comparison of expression values between the four C9orf72 lines and the four control lines revealed that 122 genes were upregulated (defined by a False Discovery Rate FDR<0.05) and 34 genes were downregulated (defined by a False Discovery Rate FDR <0.05) in C9orf72 patient fibroblasts. Conclusions: A genome wide RNA signature can be defined in fibroblasts with C9orf72 expansion. ASO-mediated reduction of C9orf72 RNA levels in fibroblasts with the hexanucleotide expansion efficiently reduced accumulation of GGGGCC RNA foci. This did not, however, generate a reversal of the C9orf72 RNA profile. Overall design: Use of Multiplex Analysis of PolyA-linked Sequences to identify expression changes in fibroblasts from amyotrophic lateral sclerosis and frontotemporal dementia patients harboring an hexanucleotide expansion in the C9orf72 gene.
Targeted degradation of sense and antisense C9orf72 RNA foci as therapy for ALS and frontotemporal degeneration.
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View SamplesPediatric Acute Myeloid Leukemia (AML) is an aggressive and poor prognosis malignancy for which there are few effective targeted approaches, despite the numerous genetic alterations, including MLL gene rearrangements (MLL-r). The histone methyltransferase DOT1L is involved in supporting proliferation of MLL-r cells, for which a target inhibitor, Pinometostat, has been evaluated in a clinical trial recruiting pediatric MLL-r leukemic patients. However, modest clinical effects have been reported. Recent studies reported that additional leukemia subtypes lacking MLL-r are sensitive to DOT1L inhibition. Here we report that targeting DOT1L with Pinometostat sensitizes pediatric AML cells to further treatment with the multi-kinase inhibitor Sorafenib, irrespectively of MLL-r. DOT1L pharmacologic inhibition induces AML cell differentiation and modulated expression of genes with relevant roles in cancer development. Such modifications in transcriptional program impact on further treatments, inducing a strong sensitization to Sorafenib, with increased apoptosis and growth suppression of both AML cell lines and primary pediatric AML cells with diverse genotypes. We used microarrays to define differential regulation of gene expression in AML cell lines with or without MLL gene rearrangements following pharmacologic inhibition of DOT1L.
Inhibition of Methyltransferase DOT1L Sensitizes to Sorafenib Treatment AML Cells Irrespective of <i>MLL</i>-Rearrangements: A Novel Therapeutic Strategy for Pediatric AML.
Treatment
View Samplesc-MYC (MYC) overexpression or hyperactivation is one of the most common drivers of human cancer. Despite intensive study, the MYC oncogene remains recalcitrant to therapeutic inhibition. Like other classic oncogenes, hyperactivation of MYC leads to collateral stresses onto cancer cells, suggesting that tumors harbor unique vulnerabilities arising from oncogenic activation of MYC. Herein, we discover the spliceosome as a new target of oncogenic stress in MYC-driven cancers. We identify BUD31 as a MYC-synthetic lethal gene, and demonstrate that BUD31 is a splicing factor required for the assembly and catalytic activity of the spliceosome. Core spliceosomal factors (SF3B1, U2AF1, and others) associate with BUD31 and are also required to tolerate oncogenic MYC. Notably, MYC hyperactivation induces an increase in total pre-mRNA synthesis, suggesting an increased burden on the core spliceosome to process pre-mRNA. In contrast to normal cells, partial inhibition of the spliceosome in MYC-hyperactivated cells leads to global intron retention, widespread defects in pre-mRNA maturation, and deregulation of many essential cell processes. Importantly, genetic or pharmacologic inhibition of the spliceosome in vivo impairs survival, tumorigenicity, and metastatic proclivity of MYC-dependent breast cancers. Collectively, these data suggest that oncogenic MYC confers a collateral stress on splicing and that components of the spliceosome may be therapeutic entry points for aggressive MYC-driven cancers. Overall design: Examination of intron rentention in MYC-ER HMECs, in 4 conditions
The spliceosome is a therapeutic vulnerability in MYC-driven cancer.
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View SamplesEpstein-Barr virus is associated with several human malignancies, including Burkitt Lymnphoma. The virus encodes more than 40 microRNAs, which participate in its possible pathogenetic role.
Molecular signature of Epstein Barr virus-positive Burkitt lymphoma and post-transplant lymphoproliferative disorder suggest different roles for Epstein Barr virus.
Specimen part, Cell line
View SamplesBitter taste receptors (T2Rs) are typical G-protein coupled receptors expressed in various tissue where they are involved in the regulation of physiological processes, thus suggesting a wider function in sensing microenvironment. We analyzed their expression and role in acute myeloid leukemia (AML). AML cells express functional T2Rs and their stimulation with the agonist, denatonium benzoate, substantially modified the AML cell transcriptomic profile and functions. GEP analysis identified relevant cellular processes affected by denatonium treatment in AML, including cell cycle, survival, migration and metabolism. More precisely, T2R activation reduced proliferation by inducing cell cycle arrest in G0/G1 phase or induced apoptosis via caspase cascade activation; impaired AML cell motility and migratory capacity; inhibited cellular respiration by decreasing glucose uptake and oxidative phosphorylation.
Denatonium as a Bitter Taste Receptor Agonist Modifies Transcriptomic Profile and Functions of Acute Myeloid Leukemia Cells.
Specimen part, Cell line, Treatment
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