AR function is altered by polyglutamine expansion and by SUMO
Ontology highlight
ABSTRACT:
ORGANISM(S): Rattus norvegicus
SUBMITTER: Andrew Lieberman
PROVIDER: E-GEOD-50383 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
Similar Datasets
Project description:Expansion of a polyglutamine (polyQ) tract in the gene for the androgen receptor (AR) results in partial loss of transactivation function and causes spinobulbar muscular atrophy (SBMA). Modification of AR by small ubiquitin-like modifier (SUMO) reduces AR function in a promoter context-dependent manner. We used microarrays to confirm and demonstrate loss of AR function from polyQ expansion and to test the degree to which AR function is altered by preventing polyQ AR SUMOylation.
2014-08-23 | GSE50383 | GEO
Project description:Spinal and bulbar muscular atrophy (SBMA) is a slowly progressing neuromuscular disease caused by a polyglutamine (polyQ)-encoding CAG repeat expansion in the androgen receptor (AR) gene, leading to AR aggregation, lower motor neuron death, and muscle atrophy. AR is a ligand-activated transcription factor that regulates neuronal architecture and promotes axon regeneration; however, whether AR transcriptional functions contribute to disease pathogenesis is not fully understood. Using a differentiated PC12 cell model of SBMA, we identified dysfunction of polyQ-expanded AR in its regulation of neurite growth and maintenance. Specifically, we found that in the presence of androgens, polyQ-expanded AR inhibited neurite outgrowth, induced neurite retraction, and inhibited neurite regrowth. This dysfunction was independent of polyQ-expanded AR transcriptional activity at androgen response elements (AREs). We further showed that the formation of polyQ-expanded AR intranuclear inclusions promoted neurite retraction, which coincided with reduced expression of the neuronal differentiation marker -III-Tubulin. Finally, we revealed that cell death is not the primary outcome for cells undergoing neurite retraction; rather, these cells become senescent. Our findings reveal that mechanisms independent of AR canonical transcriptional activity underly neurite defects in a cell model of SBMA and identify senescence as a previously unappreciated pathway implicated in this pathology. These findings suggest that, in the absence of a role for AR canonical transcriptional activity in the SBMA pathologies described here, the development of SBMA therapeutics that preserve this activity may be desirable. This approach may be broadly applicable to other polyglutamine diseases such as Huntington’s disease and spinocerebellar ataxias.
2024-07-05 | GSE267802 | GEO
Project description:Spinal and bulbar muscular atrophy (SBMA), also known as Kennedy’s Disease, is a slowly progressive adult-onset neuromuscular disease which results from a polyglutamine (polyQ) encoding CAG repeat expansion within the androgen receptor gene (AR). Despite the ubiquitous expression of the androgen receptor, it is unclear why motor neurons selectively degenerate and there are no effective treatments or disease modifying therapies for this debilitating disease. In order to identify potential therapeutic targets, we set out to establish the genes and molecular pathways involved in early motor neuron dysfunction in SBMA. We therefore undertook global transcriptomic profiling of cultured primary embryonic motor neurons from the spinal cord of AR100 mice, which model SBMA.. Four biological replicate samples were used for genome wide analysis using Affymetrix 430 v2.0 mouse arrays. Data was normalised using therobust multichip average (RMA) algorithm.
2019-05-02 | E-MTAB-6986 | biostudies-arrayexpress
Project description:Spinobulbar muscular atrophy (SBMA) is a neurodegenerative disease caused by expansion of a polyglutamine tract in the androgen receptor (AR). This mutation confers toxic function to AR through unknown mechanisms. Mutant AR toxicity requires binding of its hormone ligand, suggesting that pathogenesis involves ligand-induced changes in AR. However, whether toxicity is mediated by native AR function or a novel AR function is unknown. We systematically investigated events downstream of ligand-dependent AR activation in a Drosophila model of SBMA. We show that nuclear translocation of AR is necessary but not sufficient for toxicity and that DNA binding by AR is necessary for toxicity. Mutagenesis studies demonstrated that a functional AF-2 domain is essential for toxicity, a finding corroborated by a genetic screen that identified AF-2 interactors as dominant modifiers of degeneration. These findings indicate that SBMA pathogenesis is mediated by misappropriation of native protein function, a mechanism that may apply broadly to polyglutamine diseases.
2010-09-23 | GSE23802 | GEO
Project description:Spinobulbar muscular atrophy (SBMA) is a neurodegenerative disease caused by expansion of a polyglutamine tract in the androgen receptor (AR). This mutation confers toxic function to AR through unknown mechanisms. Mutant AR toxicity requires binding of its hormone ligand, suggesting that pathogenesis involves ligand-induced changes in AR. However, whether toxicity is mediated by native AR function or a novel AR function is unknown. We systematically investigated events downstream of ligand-dependent AR activation in a Drosophila model of SBMA. We show that nuclear translocation of AR is necessary but not sufficient for toxicity and that DNA binding by AR is necessary for toxicity. Mutagenesis studies demonstrated that a functional AF-2 domain is essential for toxicity, a finding corroborated by a genetic screen that identified AF-2 interactors as dominant modifiers of degeneration. These findings indicate that SBMA pathogenesis is mediated by misappropriation of native protein function, a mechanism that may apply broadly to polyglutamine diseases. We used Affymetrix arrays to generate a molecular phenotype of degeneration in profile flies expressing wild-type or polyglutamine-expanded AR. We also expressed in the fly eye polyglutamine-expanded AR with point mutations affecting the DNA binding domain and the AF-2 domain. In some experiments, GMR-GAL4; UAR-AR flies were crossed to flies carrying a chromosomal duplication of the limpet gene. Transgene expression was induced in the eye using GMR-GAL4. Flies were crossed at 29 deg C on food containing either 1mM DHT or 1% ethanol (vehicle).
2010-09-23 | E-GEOD-23802 | biostudies-arrayexpress
Project description:Spinal and bulbar muscular atrophy (SBMA) is a neuromuscular disorder caused by a polyglutamine expansion in the androgen receptor (AR). Previous studies have shown that transcriptional dysregulation and mitochondrial impairment occur in SBMA. We used gene-expression analysis and ChIP-sequencing to map transcriptional changes in SBMA induced pluripotent stem cell-derived motor neurons. The SBMA cells had decreased expression of genes encoding electron transport chain subunits and other metabolic proteins, associated with reduced histone acetylation which may be contributing to mitochondrial dysfunction. AR ChIP-sequencing results indicate that this is not a direct transcriptional effect of mutant AR on mitochondrial gene expression. Furthermore, we found decreased acetyl-CoA, and pyruvate supplementation to correct this deficiency improved mitochondrial function and SBMA motor neuron viability. We propose that epigenetic dysregulation of metabolic genes contributes to reduced mitochondrial ATP production. Our results show a molecular link between altered epigenetic regulation and mitochondrial metabolism that contributes to neurodegeneration.
2020-08-10 | GSE140016 | GEO
Project description:Spinal and bulbar muscular atrophy (SBMA) is a neuromuscular disorder caused by a polyglutamine expansion in the androgen receptor (AR). Previous studies have shown that transcriptional dysregulation and mitochondrial impairment occur in SBMA. We used gene-expression analysis and ChIP-sequencing to map transcriptional changes in SBMA induced pluripotent stem cell-derived motor neurons. The SBMA cells had decreased expression of genes encoding electron transport chain subunits and other metabolic proteins, associated with reduced histone acetylation which may be contributing to mitochondrial dysfunction. AR ChIP-sequencing results indicate that this is not a direct transcriptional effect of mutant AR on mitochondrial gene expression. Furthermore, we found decreased acetyl-CoA, and pyruvate supplementation to correct this deficiency improved mitochondrial function and SBMA motor neuron viability. We propose that epigenetic dysregulation of metabolic genes contributes to reduced mitochondrial ATP production. Our results show a molecular link between altered epigenetic regulation and mitochondrial metabolism that contributes to neurodegeneration.
2020-08-10 | GSE140015 | GEO
Project description:Spinal and bulbar muscular atrophy (SBMA) is a neuromuscular disorder caused by a polyglutamine expansion in the androgen receptor (AR). Previous studies have shown that transcriptional dysregulation and mitochondrial impairment occur in SBMA. We used gene-expression analysis and ChIP-sequencing to map transcriptional changes in SBMA induced pluripotent stem cell-derived motor neurons. The SBMA cells had decreased expression of genes encoding electron transport chain subunits and other metabolic proteins, associated with reduced histone acetylation which may be contributing to mitochondrial dysfunction. AR ChIP-sequencing results indicate that this is not a direct transcriptional effect of mutant AR on mitochondrial gene expression. Furthermore, we found decreased acetyl-CoA, and pyruvate supplementation to correct this deficiency improved mitochondrial function and SBMA motor neuron viability. We propose that epigenetic dysregulation of metabolic genes contributes to reduced mitochondrial ATP production. Our results show a molecular link between altered epigenetic regulation and mitochondrial metabolism that contributes to neurodegeneration.
2020-08-10 | GSE140017 | GEO
Project description:Kennedy’s disease/Spinobulbar muscular atrophy (KD/SBMA) is a degenerative neuromuscular disease affecting males. This disease is caused by polyglutamine expansion mutations of the androgen receptor (AR) gene. Although KD/SBMA has been traditionally considered a motor neuron disease, emerging evidence points to a central etiological role of muscle. We previously reported a microarray study of genes regulated in muscle of three genetically unique mouse models of KD/SBMA but were unable to those which are androgen-dependent or are associated with onset of symptoms. Methodology/principal findings: In the current study we examined the time course and androgen-dependence of transcriptional changes in the HSA-AR transgenic (Tg) mouse model, in which females have a severe phenotype after acute testosterone treatment. Using microarray analysis we identified regulated genes at the onset and peak of muscle weakness in testosterone-treated Tg females. We found both transient and persistent groups of regulated genes and analysis of gene function indicated functional groups such as mitochondrion, ion and nucleotide binding, muscle development, and sarcomere maintenance. By comparing the current results with those from the three previously reported models we were able to identify KD/SBMA candidate genes that are androgen dependent, and occur early in the disease process, properties which are promising for targeted therapeutics.
2015-03-22 | GSE61886 | GEO
Project description:Transcription factors (TFs) activate enhancers to drive cell-specific gene expression in response to signals, but our understanding of enhancer assembly in signaling events is incomplete. Here we show that Androgen Receptor (AR), a steroid hormone signaling-regulated transcription factor, forms phase-separated condensates in response to androgen to activate enhancers. We demonstrate that the intrinsically disordered NTD of AR drives condensate formation and that NTD deletion or aromatic residue mutation reduces AR self-association and abolishes AR transcriptional activity. AR NTD can be substituted by some IDRs from other proteins for AR condensation capacity and transactivation function. Extending the polyQ tract within AR NTD strengthens AR phase separation and also leads to impaired transcriptional activity. PolyQ expansion does not affect AR binding on enhancers, but instead impairs enhancer assembly. These results suggest that AR phase separation mediates enhancer assembly, and an optimal level of AR condensation is required for its proper function in mediating AR-AR homotypic and AR-cofactor heterotypic interactions to regulate transcription in response to signals. Our study supports that alteration of the fine-tuned protein condensation might underlie AR-related human pathologies, therefore providing novel molecular insights for potential therapeutic strategies to treat prostate cancer and other AR-involved diseases by targeting AR condensation.
2023-10-31 | GSE215161 | GEO