Project description:Histone deacetylase (HDAC) 4 is a transcriptional repressor that contains a glutamine rich domain. We hypothesised that it may be involved in the molecular pathogenesis of Huntington's disease (HD), a protein folding neurodegenerative disorder caused by an aggregation-prone polyglutamine expansion and transcriptional dysregulation. We found that HDAC4 interacts with huntingtin in a polyglutamine-length dependent manner and co-localises with cytoplasmic inclusions. We show that HDAC4 reduction delayed cytoplasmic aggregate formation, restored Bdnf transcript levels and rescued neuronal and cortico-striatal synaptic function in HD mouse models. This was accompanied by an improvement in motor co-ordination, neurological phenotypes and increased lifespan. Surprisingly, HDAC4 reduction had no effect on global transcriptional dysfunction and did not modulate nuclear huntingtin aggregation. Our results define a crucial role for cytoplasmic aggregation in the molecular pathology of HD. HDAC4 reduction presents a novel strategy for targeting huntingtin aggregation which may be amenable to small molecule therapeutics. mRNA expression analysis was performed by microarray in 9 weeks old WT (n=9), R6/2 (n=9), HDAC4het (n=9) and Double R6/2::HDAC4het (n=10) mice. Microarray quality control was performed using the software package provided on RACE (http://race.unil.ch).
Project description:Histone deacetylase (HDAC) 4 is a transcriptional repressor that contains a glutamine rich domain. We hypothesised that it may be involved in the molecular pathogenesis of Huntington's disease (HD), a protein folding neurodegenerative disorder caused by an aggregation-prone polyglutamine expansion and transcriptional dysregulation. We found that HDAC4 interacts with huntingtin in a polyglutamine-length dependent manner and co-localises with cytoplasmic inclusions. We show that HDAC4 reduction delayed cytoplasmic aggregate formation, restored Bdnf transcript levels and rescued neuronal and cortico-striatal synaptic function in HD mouse models. This was accompanied by an improvement in motor co-ordination, neurological phenotypes and increased lifespan. Surprisingly, HDAC4 reduction had no effect on global transcriptional dysfunction and did not modulate nuclear huntingtin aggregation. Our results define a crucial role for cytoplasmic aggregation in the molecular pathology of HD. HDAC4 reduction presents a novel strategy for targeting huntingtin aggregation which may be amenable to small molecule therapeutics. mRNA expression analysis was performed by microarray in 15 weeks old WT (n=8), R6/2 (n=9), HDAC4het (n=8) and Double R6/2::HDAC4het (n=9) mice. Microarray quality control was performed using the software package provided on RACE (http://race.unil.ch).
Project description:Histone deacetylase (HDAC) 4 is a transcriptional repressor that contains a glutamine rich domain. We hypothesised that it may be involved in the molecular pathogenesis of Huntington’s disease (HD), a protein folding neurodegenerative disorder caused by an aggregation-prone polyglutamine expansion and transcriptional dysregulation. We found that HDAC4 interacts with huntingtin in a polyglutamine-length dependent manner and co-localises with cytoplasmic inclusions. We show that HDAC4 reduction delayed cytoplasmic aggregate formation, restored Bdnf transcript levels and rescued neuronal and cortico-striatal synaptic function in HD mouse models. This was accompanied by an improvement in motor co-ordination, neurological phenotypes and increased lifespan. Surprisingly, HDAC4 reduction had no effect on global transcriptional dysfunction and did not modulate nuclear huntingtin aggregation. Our results define a crucial role for cytoplasmic aggregation in the molecular pathology of HD. HDAC4 reduction presents a novel strategy for targeting huntingtin aggregation which may be amenable to small molecule therapeutics.
Project description:Histone deacetylase (HDAC) 4 is a transcriptional repressor that contains a glutamine rich domain. We hypothesised that it may be involved in the molecular pathogenesis of Huntington’s disease (HD), a protein folding neurodegenerative disorder caused by an aggregation-prone polyglutamine expansion and transcriptional dysregulation. We found that HDAC4 interacts with huntingtin in a polyglutamine-length dependent manner and co-localises with cytoplasmic inclusions. We show that HDAC4 reduction delayed cytoplasmic aggregate formation, restored Bdnf transcript levels and rescued neuronal and cortico-striatal synaptic function in HD mouse models. This was accompanied by an improvement in motor co-ordination, neurological phenotypes and increased lifespan. Surprisingly, HDAC4 reduction had no effect on global transcriptional dysfunction and did not modulate nuclear huntingtin aggregation. Our results define a crucial role for cytoplasmic aggregation in the molecular pathology of HD. HDAC4 reduction presents a novel strategy for targeting huntingtin aggregation which may be amenable to small molecule therapeutics.
Project description:Transcriptional dysregulation is an early feature of Huntington's disease (HD). We observed gene-specific changes in H3K4me3 at transcriptionally repressed promoters in R6/2 mouse and human HD brain. Genome-wide analysis showed a novel chromatin signature for this mark. Reducing the levels of the H3K4 demethylase SMCX/Jarid1c in primary neurons reversed down-regulation of key neuronal genes caused by mutant Huntingtin (Htt) expression. Finally, reduction of SMCX/Jarid1c in primary neurons from BACHD mice or the single Jarid1 in a Drosophila HD model was protective. Therefore, targeting this epigenetic signature may be an effective strategy to ameliorate the consequences of HD. mRNA-seq in wild type and R6/2 cortex and striatum at 8 and 12 weeks.
Project description:Transcriptional dysregulation is an early feature of Huntington's disease (HD). We observed gene-specific changes in H3K4me3 at transcriptionally repressed promoters in R6/2 mouse and human HD brain. Genome-wide analysis showed a novel chromatin signature for this mark. Reducing the levels of the H3K4 demethylase SMCX/Jarid1c in primary neurons reversed down-regulation of key neuronal genes caused by mutant Huntingtin (Htt) expression. Finally, reduction of SMCX/Jarid1c in primary neurons from BACHD mice or the single Jarid1 in a Drosophila HD model was protective. Therefore, targeting this epigenetic signature may be an effective strategy to ameliorate the consequences of HD. ChIP-seq for H3K4me3 in wild type and R6/2 cortex and striatum at 8 and 12 weeks.
Project description:Transcriptional alterations are characteristic of persistent pain states but the key regulators remain elusive. Using a conditional knockout (cKO) strategy in mice we sought to determine whether loss of the transcriptional co-repressor histone deacetylase four (HDAC4) would have implications for sensory neuron transcription and nociception. HDAC4 was found to be largely dispensable for transcriptional regulation of naïve sensory neurons but was required for transcriptional responses after injury, with Calca and Trpv1 expression consistently downregulated in HDAC4 cKO compared to littermate controls (0.2-0.44 fold). This downregulation corresponded to reduced sensitivity to capsaicin in vitro (76% +/- 4.4% wildtype capsaicin responders vs 56.9% +/- 4.7% cKO responders) and to reduced thermal hypersensitivity in the complete Freund’s adjuvant model of inflammatory pain (1.3-1.4 fold improvement). These data indicate that HDAC4 is a novel inflammatory pain mediator and may be a good therapeutic target, capable of orchestrating the regulation of multiple downstream effectors. Total RNA was extracted from HDAC4 cKO and HDAC4 fl/fl naïve adult lumbar dorsal root ganglia (n=3/group). mRNA expression was compared using Affymetrix Mouse Gene Arrays (Mouse Gene 2.0ST) run on a GeneChip Fluidics Station 450. Chips were scanned on an Affymetrix GeneChip Scanner.
Project description:Transcriptional dysregulation is an early feature of Huntington's disease (HD). We observed gene-specific changes in H3K4me3 at transcriptionally repressed promoters in R6/2 mouse and human HD brain. Genome-wide analysis showed a novel chromatin signature for this mark. Reducing the levels of the H3K4 demethylase SMCX/Jarid1c in primary neurons reversed down-regulation of key neuronal genes caused by mutant Huntingtin (Htt) expression. Finally, reduction of SMCX/Jarid1c in primary neurons from BACHD mice or the single Jarid1 in a Drosophila HD model was protective. Therefore, targeting this epigenetic signature may be an effective strategy to ameliorate the consequences of HD.
Project description:Transcriptional dysregulation is an early feature of Huntington's disease (HD). We observed gene-specific changes in H3K4me3 at transcriptionally repressed promoters in R6/2 mouse and human HD brain. Genome-wide analysis showed a novel chromatin signature for this mark. Reducing the levels of the H3K4 demethylase SMCX/Jarid1c in primary neurons reversed down-regulation of key neuronal genes caused by mutant Huntingtin (Htt) expression. Finally, reduction of SMCX/Jarid1c in primary neurons from BACHD mice or the single Jarid1 in a Drosophila HD model was protective. Therefore, targeting this epigenetic signature may be an effective strategy to ameliorate the consequences of HD.
Project description:Huntington's disease (HD) is a devastating neurodegenerative disorder caused by the expansion of CAG repeats in the huntingtin (HTT) gene. Recent advances in gene editing technologies, such as CRISPR/CasRx, have opened new avenues for therapeutic interventions. In this study, we explored the efficacy of CRISPR/CasRx, which can specifically and accurately digest single-stranded RNA and down-regulate the expression of related genes, in targeting the HTT mRNA and its potential as a treatment strategy for HD. Our results showed that CRISPR/CasRx could significantly down-regulate HTT mRNA in different models, including human embryonic kidney (HEK) 293T cells, HD140Q-knockin (HD 140Q-KI) mice at various disease stages, and Huntingtin knockin (HD-KI) pigs, and lead to a subsequent decrease in the expression of mutant Huntingtin (mHTT) protein. Moreover, this intervention could significantly ameliorate the neurological symptoms in HD 140Q-KI mice and HD-KI pigs. These findings highlight the effectiveness of the RNA-targeting CRISPR/CasRx as a potential therapeutic strategy for HD. Furthermore, the success of this approach provides valuable insights and novel avenues for the treatment of other genetic disorders caused by gene mutations.