Experimental replacement therapy counters decreased IGF-1 levels in Huntington’s disease
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE19291 | GEO | 2018/10/01
REPOSITORIES: GEO
Similar Datasets
Project description:Huntington’s disease (HD) is a dominantly inherited genetic disease caused by mutant huntingtin (htt) protein with expanded polyglutamine tracts. A neuropathological hallmark of HD is the presence of neuronal inclusions of mutant htt. p62 is an important regulatory protein in selective autophagy, a process by which aggregated proteins are degraded, and it is associated with several neurodegenerative disorders including HD. Here we investigated the effect of p62 depletion in three HD model mice: R6/2, HD190QG and HD120QG mice. We found that loss of p62 in these models led to longer lifespans and reduced nuclear inclusions, although cytoplasmic inclusions increased with polyglutamine length. In mouse embryonic fibroblasts (MEFs) with or without p62, mutant htt with a nuclear localization signal (NLS) showed no difference in nuclear inclusion between the two MEF types. In the case of mutant htt without NLS, however, p62 depletion increased cytoplasmic inclusions. Furthermore, to examine the effect of impaired autophagy in HD model mice, we crossed R6/2 mice with Atg5 conditional knockout mice. These mice also showed decreased nuclear inclusions and increased cytoplasmic inclusions, similar to HD mice lacking p62. These data suggest that the genetic ablation of p62 in HD model mice enhances cytoplasmic inclusion formation by interrupting autophagic clearance of polyQ inclusions. This reduces polyQ nuclear influx and paradoxically ameliorates disease phenotypes by decreasing toxic nuclear inclusions. Gene expression profiles were analyzed to examine the effects of p62 depletion in mouse with or without mutant huntingtin exon 1
2014-10-10 | GSE62210 | GEO
Project description:Pluripotent stem cells undergo unlimited self-renewal while maintaining their potential to differentiate into post-mitotic cells with an intact proteome, a capacity that demands a highly induced proteostasis network. As such, induced pluripotent stem cells (iPSCs) suppress the aggregation of polyQ-expanded huntingtin (HTT), the mutant protein underlying Huntington’s disease (HD). Here we show that proteasome activity determines HTT levels, preventing the accumulation of polyQ-expanded aggregates in iPSCs from HD patients (HD-iPSCs). iPSCs exhibit intrinsic high levels of UBR5, an E3 ubiquitin ligase that we find required for proteasomal degradation of both normal and mutant HTT. When UBR5 fails to monitor HTT proteostasis, the concomitant up-regulation of HTT expression particularly results in polyQ-expanded aggregation in HD-iPSCs. Moreover, UBR5 knockdown hastens protein aggregation and neurotoxicity in polyQ-expanded invertebrate models. Notably, ectopic expression of UBR5 is sufficient to induce polyubiquitination and degradation of mutant HTT, reducing polyQ-expanded aggregates in HD cell models. However, UBR5 is dispensable for the proteostasis of other aggregation-prone proteins linked with Machado-Joseph disease or amyotrophic lateral sclerosis in iPSCs. Besides its role in HTT regulation, we find that intrinsic high levels of UBR5 also determine the global proteostatic ability of iPSCs preventing aggresome formation, suggesting a role in the control of misfolded proteins ensued from normal metabolism. Thus, our findings indicate UBR5 as a central component of super-vigilant proteostasis of iPSCs with the potential to correct proteostatic deficiencies in HD.
2018-06-14 | PXD009803 | Pride
Project description:Huntington’s disease (HD) is a neurodegenerative disorder caused by expansion of a CAG trinucleotide repeat in the Huntingtin (HTT) gene, encoding a homopolymeric polyglutamine (polyQ) tract. Although mutant HTT (mHTT) protein is known to aggregate, the links between aggregation and neurotoxicity remain unclear. Here we show that both translation and aggregation of wild-type and mHTT are regulated by a stress-responsive upstream open reading frame, and that polyQ expansions cause abortive translation termination and release of truncated, aggregation-prone mHTT fragments. Notably, we find that mHTT depletes translation elongation factor eIF5A in brains of symptomatic HD mice and cultured HD cells, leading to pervasive ribosome pausing and collisions. Loss of eIF5A disrupts homeostatic controls and impairs recovery from acute stress. Importantly, drugs that inhibit translation initiation reduce premature termination and mitigate this escalating cascade of ribotoxic stress and dysfunction in HD.
2024-03-13 | PXD026012 | Pride
Project description:The amplification of a CAG repeat in the gene coding for huntingtin (HTT) leads to Huntington’s disease (HD). At the protein level, this translates into the expansion of a poly-glutamine (polyQ) stretch in the HTT N-terminus, which renders HTT aggregation-prone by unknown mechanisms. Here we investigate the effects of polyQ expansion on the HTT-HAP40 complex, where HTT structure is substantially stabilized. Surprisingly, our biophysical, cryo-EM and crosslinking mass spectrometry experiments reveal no major changes between 17QHTT-HAP40 (wild type), 46QHTT-HAP40 (typical polyQ length in HD patients) and 128QHTT-HAP40 (extreme polyQ length). Thus, the proposed destabilizing effect of HTT polyQ expansion may not suffice to alter the HTT-HAP40 complex, suggesting that polyQ expansion does not have a major global effect on HTT structure.
2021-03-19 | PXD018451 | Pride
Project description:Huntington's disease (HD) is a dominantly inherited genetic disease caused by mutant huntingtin (htt) protein with expanded polyglutamine tracts. A neuropathological hallmark of HD is the presence of neuronal inclusions of mutant htt. p62 is an important regulatory protein in selective autophagy, a process by which aggregated proteins are degraded, and it is associated with several neurodegenerative disorders including HD. Here we investigated the effect of p62 depletion in three HD model mice: R6/2, HD190QG and HD120QG mice. We found that loss of p62 in these models led to longer lifespans and reduced nuclear inclusions, although cytoplasmic inclusions increased with polyglutamine length. In mouse embryonic fibroblasts (MEFs) with or without p62, mutant htt with a nuclear localization signal (NLS) showed no difference in nuclear inclusion between the two MEF types. In the case of mutant htt without NLS, however, p62 depletion increased cytoplasmic inclusions. Furthermore, to examine the effect of impaired autophagy in HD model mice, we crossed R6/2 mice with Atg5 conditional knockout mice. These mice also showed decreased nuclear inclusions and increased cytoplasmic inclusions, similar to HD mice lacking p62. These data suggest that the genetic ablation of p62 in HD model mice enhances cytoplasmic inclusion formation by interrupting autophagic clearance of polyQ inclusions. This reduces polyQ nuclear influx and paradoxically ameliorates disease phenotypes by decreasing toxic nuclear inclusions. Gene expression profiles were analyzed to examine the effects of p62 depletion in mouse with or without mutant huntingtin exon 1 To examine the effect of p62 depletion on the transcriptome of Huntington's disease model mice, we crossed p62 knockout mice with HD model mice. We extracted total RNA from the striatum of these mice at 8 weeks and used for a microaaray analysis. The samples are HD transgenic mice with p62 knockout (HD_p62KO), HD mice with normal p62 (HD_p62WT), non-HD-transgenic mice with p62 knockout (NT_p62KO), and non-HD-transgenic mice with normal p62 (NT_p62WT).
2014-10-10 | E-GEOD-62210 | biostudies-arrayexpress
Project description:Huntington’s disease (HD) is an incurable inherited disorder caused by repeat expansion in the huntingtin gene (Htt). The mutant protein causes neuronal degeneration leading to severe motor and psychological abnormalities. Selective downregulation of the mutant Htt by targeting Spt4/Spt5 or the Spt5-PolII transcription elongation complexes was proposed as a potential therapy. We report the identification of SPI-24 and SPI-77 small molecule inhibitors of Spt5-PolII that selectively lower mutant Htt. In the BACHD mouse model of HD, direct delivery to the striatum, subcutaneous injection and oral administration of these inhibitors diminished mutant Htt levels, ameliorated mitochondrial dysfunction and restored BDNF expression. Prolonged treatment attenuated motor and anxious-like phenotypes of HD mice and delayed disease deterioration. SPI-24 long-term treatment had no side-effects or global changes in gene expression. Mechanistically, SPIs reduce Spt5 and PolII occupancies of mutant Htt. Thus, SPIs can be an effective therapeutic strategy for HD.
2023-11-20 | GSE225788 | GEO
Project description:Huntington’s disease (HD) is an incurable inherited disorder caused by repeat expansion in the huntingtin gene (Htt). The mutant protein causes neuronal degeneration leading to severe motor and psychological abnormalities. Selective downregulation of the mutant Htt by targeting Spt4/Spt5 or the Spt5-PolII transcription elongation complexes was proposed as a potential therapy. We report the identification of SPI-24 and SPI-77 small molecule inhibitors of Spt5-PolII that selectively lower mutant Htt. In the BACHD mouse model of HD, direct delivery to the striatum, subcutaneous injection and oral administration of these inhibitors diminished mutant Htt levels, ameliorated mitochondrial dysfunction and restored BDNF expression. Prolonged treatment attenuated motor and anxious-like phenotypes of HD mice and delayed disease deterioration. SPI-24 long-term treatment had no side-effects or global changes in gene expression. Mechanistically, SPIs reduce Spt5 and PolII occupancies of mutant Htt. Thus, SPIs can be an effective therapeutic strategy for HD.
2023-11-20 | GSE225789 | GEO
Project description:We have developed a web-based platform for HTT PPI visualization, exploration, and multi-omic integration called HTT-OMNI. We demonstrate the utility of this platform not only for exploring and filtering existing huntingtin (HTT) PPIs, but also for investigating user-generated omics datasets. For example, we demonstrate the comparison of a published HTT IP-MS experiment, performed in the striatum brain region of a mouse HD model, to unpublished HTT IP-MS experiments in the cortex brain region. Overall, HTT-OMNI summarizes and integrates known HTT PPIs with polyQ-dependent transcriptome and proteome measurements, providing an all-in-one exploratory platform that facilitates the prioritization of target genes that may contribute to HD pathogenesis.
2022-08-15 | PXD034158 | Pride
Project description:Abstract - Huntingtin (Htt) protein interacts with many transcriptional regulators, with widespread disruption to the transcriptome in Huntington’s disease (HD) brought about by altered interactions with the mutant Htt (muHtt) protein. Repressor Element-1 Silencing Transcription Factor (REST) is a repressor whose association with Htt in the cytoplasm is disrupted in HD, leading to increased nuclear REST and concomitant repression of several neuronal-specific genes, including brain-derived neurotrophic factor (Bdnf). Here, we explored a wide set of HD dysregulated genes to identify direct REST targets whose expression is altered in a cellular model of HD but that can be rescued by knock-down of REST activity. We found many direct REST target genes encoding proteins important for nervous system development, including a cohort involved in synaptic transmission, at least two of which can be rescued at the protein level by REST knock-down. We also identified several microRNAs (miRNAs) whose aberrant repression is directly mediated by REST, including miR-137, which has not previously been shown to be a direct REST target in mouse. These data provide evidence of the contribution of inappropriate REST-mediated transcriptional repression to the widespread changes in coding and non-coding gene expression in a cellular model of HD that may affect normal neuronal function and survival.
2013-01-03 | GSE42107 | GEO
Project description:Huntington’s disease (HD) is caused by expanded CAG repeats in the Huntingtin gene (HTT) that results in expression of mutant HTT proteins (mHTT) with extended polyglutamine tracts in diverse cells of the body, including striatal neurons and astrocytes. The relative contributions of neurons and astrocytes to disease pathogenesis are unknown for HD and other neurodegenerative diseases. This is a critical issue to address since it has been proposed that neuronal loss in HD and other major neurodegenerative diseases is downstream of astrocytic dysfunction that drives neuronal death. Moreover, astrocyte-to-neuron conversion is considered a promising approach in HD and other neurodegenerative diseases with little reported detriment with regards to normal astrocytic physiological functions, which are varied and extensive in health and disease. Thus, astrocytes are considered both causative and also largely replaceable in neurodegeneration, and their basic contributions to disease pathophysiology relative to neurons remain undefined in vivo. We used genetically encoded and cell-specific zinc finger protein (ZFP) transcriptional repressors to lower mHTT and molecularly dissected neuronal and astrocytic influences on HD pathophysiology at molecular, cellular, and behavioral levels. We found that the major disease drivers were in fact neurons, with astrocytes displaying lesser loss of essential functions such as cholesterol metabolism that were downstream of greater neuronal dysfunction, which encompassed neuromodulation, synaptic, and intracellular signaling. We thus dissected the cell autonomous and non-cell autonomous mechanistic and causal contributions of both neurons and astrocytes to a complex neurodegenerative disease in vivo with wider implications for rescue and repair strategies.
2022-12-15 | PXD030021 | Pride