Reversible protein acetylation provides a central mechanism for controlling gene expression and cellular signaling events. It is governed by the antagonistic commitment of two enzymes families: the histone acetyltransferases (HATs) and the histone deacetylases (HDACs). HDAC4, like its class IIa counterparts, is a potent transcriptional repressor through interactions with tissue-specific transcription factors via its N-terminal domain. Whilst the lysine deacetylase activity of the class IIa HDACs is much less potent than that of the class I enzymes, HDAC4 has been reported to influence protein deacetylation through its interaction with HDAC3.
HDAC4 does not act as a protein deacetylase in the postnatal murine brain in vivo.
Sex, Specimen part
View SamplesPurpose: Transcriptome profiling (RNA-seq) to microarray to evaluate transcriptional changes in the heart of HD mouse models Methods: Heart mRNA profiles of 4-weeks-old wild-type (WT) and R6/2 transgenic; 15-weeks-old WT and R6/2 transgenic mice; 8-month-old WT and HdhQ150 knock-in mice; 22-month-old WT and HdhQ150 knock-in mice were generated by deep sequencing, in triplicate, using Illumina Hi-seq 2000. Conclusions: Our study showed that there is no major transcriptional deregulation in the heart of mouse models of HD. Overall design: Heart mRNA profiles of 4-weeks-old wild-type (WT) and R6/2 transgenic; 15-weeks-old WT and R6/2 transgenic mice; 8-month-old WT and HdhQ150 knock-in mice; 22-month-old WT and HdhQ150 knock-in mice were generated by deep sequencing, in triplicate, using Illumina Hi-seq 2000.
Dysfunction of the CNS-heart axis in mouse models of Huntington's disease.
No sample metadata fields
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HDAC4 reduction: a novel therapeutic strategy to target cytoplasmic huntingtin and ameliorate neurodegeneration.
Sex, Age, Specimen part
View SamplesHistone 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 Huntingtons 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.
HDAC4 reduction: a novel therapeutic strategy to target cytoplasmic huntingtin and ameliorate neurodegeneration.
Sex, Age, Specimen part
View SamplesHistone 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 Huntingtons 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.
HDAC4 reduction: a novel therapeutic strategy to target cytoplasmic huntingtin and ameliorate neurodegeneration.
Sex, Age, Specimen part
View SamplesHuntington's disease (HD) is an inherited neurodegenerative disorder of which skeletal muscle atrophy is a common feature, and multiple lines of evidence support a muscle-based pathophysiology in HD mouse models. Inhibition of myostatin signaling increases muscle mass, and therapeutic approaches based on this are in clinical development. We have used a soluble ActRIIB decoy receptor (ACVR2B/Fc) to test the effects of myostatin/activin A inhibition in the R6/2 mouse model of HD. Transcriptional profiling of muscle in treated and untreated wild-type and R6/2 mice was performed to analyze the effect of the ActRIIB decoy on genes and pathways involved in maintaining normal muscle physiology as well as those dysregulated due to the mutant HTT gene mutation. Overall design: RNAseq was performed on tibialis muscle from wild-type, wildtype + decoy, R6/2 and R6/2 + decoy; N = 10 per group. RNAseq was done on an Illumina Hi-seq 2000. Paired-end sequencing was obtained, 4-plexed across lanes for a minimum of 38 million 50mer paired reads per sample
Myostatin inhibition prevents skeletal muscle pathophysiology in Huntington's disease mice.
Sex, Age, Specimen part, Cell line, Treatment, Subject
View SamplesNo description.
Age-associated changes in expression of small, noncoding RNAs, including microRNAs, in C. elegans.
Cell line, Subject
View SamplesMED1 (Mediator complex subunit 1) is expressed by human epidermal keratinocytes and functions as a coactivator of several transcription factors. To elucidate the role of MED1 in keratinocytes, we established keratinocyte-specific MED1-null (MED1epi-/-) mice using the K5Cre-LoxP system.
Roles of MED1 in quiescence of hair follicle stem cells and maintenance of normal hair cycling.
Specimen part
View SamplesRoux-en-Y gastric bypass (RYGB) is the most effective therapy for morbid obesity, but it has a ~20% failure rate. We used our established RYGB model in diet-induced obese (DIO) Sprague-Dawley rats, which reproduces human bi-phasic body weight (BW) loss pattern, to determine mechanisms contributing to success (RGYB-S) or failed (RYGB-F) RYGB. DIO rats were randomized to RYGB, sham operated Obese, and sham operated obese pair fed-linked to RYGB (PF) groups. BW, caloric intake (CI) and fecal output (FO) were recorded daily for 90 days, food efficiency (FE) was calculated, and morphologic changes were determined. Gut, adipose and thyroid hormones were measured in plasma. Mitochondrial respiratory complexes in skeletal muscle, expression of energy-related hypothalamic and fat peptides, receptors and enzymes were quantified. A 25% failure rate occurred. RYGB-S, RYGB-F and PF rats vs. Obese showed rapid BW decrease, followed by sustained BW loss in RYGB-S. RYGB-F and PF gradually increased BW. Expression profiling of both CNS (hypothalamus) and peripheral tissues (subcutaneous abdominal fat) strongly supported the involvement of a number of metabolic and feeding-related genes in the differential outcomes.
Characterization of weight loss and weight regain mechanisms after Roux-en-Y gastric bypass in rats.
No sample metadata fields
View SamplesCyclin C was cloned as a growth-promoting G1 cyclin, and was also shown to regulate gene transcription. Here we report that in vivo cyclin C acts as a haploinsufficient tumour suppressor, by controlling Notch1 oncogene levels. Cyclin C activates an 'orphan' CDK19 kinase, as well as CDK8 and CDK3. These cyclin-C-CDK complexes phosphorylate the Notch1 intracellular domain (ICN1) and promote ICN1 degradation. Genetic ablation of cyclin C blocks ICN1 phosphorylation in vivo, thereby elevating ICN1 levels in cyclin-C-knockout mice. Cyclin C ablation or heterozygosity collaborates with other oncogenic lesions and accelerates development of T-cell acute lymphoblastic leukaemia (T-ALL). Furthermore, the cyclin C encoding gene CCNC is heterozygously deleted in a significant fraction of human T-ALLs, and these tumours express reduced cyclin C levels. We also describe point mutations in human T-ALL that render cyclin-C-CDK unable to phosphorylate ICN1. Hence, tumour cells may develop different strategies to evade inhibition by cyclin C.
Cyclin C is a haploinsufficient tumour suppressor.
Specimen part
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