PGC-1alpha pathway dysregulation disrupts myofiber specification in a mouse model of SBMA
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE329198 | GEO | 2026/05/01
REPOSITORIES: GEO
Similar Datasets
Project description:Skeletal muscle pathology is a critical but poorly understood contributor to neuromuscular degeneration in spinal and bulbar muscular atrophy (SBMA), a CAG/polyglutamine (polyQ) expansion disorder caused by mutation in the androgen receptor (AR). Using a gene-targeted SBMA mouse model, we applied single-nucleus RNA sequencing to identify a previously unrecognized, disease-specific population of skeletal muscle myonuclei that replace normal myonuclear subtypes. This transition was driven by dysregulation of the PGC-1α pathway, a central regulator of myofiber specification and metabolic identity. PGC-1α dysfunction in SBMA muscle was age-, hormone-, and polyQ length–dependent and was partially rescued by subcutaneous delivery of AR-targeted antisense oligonucleotides. Integrated ChIP-seq and RNA-seq analyses revealed that aberrant PGC-1α activity promoted the expression of a distinct set of myofiber specification genes while downregulating those defining healthy Type IIb and Type IIx myonuclei. We propose a model in which this dysfunction arose downstream of polyQ-mediated sequestration of PGC-1α cofactors MEF2, CREB, and CBP, leading to transcriptional reprogramming and cellular dysfunction. These findings implicate PGC-1α dysregulation as a key event linking AR polyQ expansion to skeletal muscle degeneration and suggest a shared mechanism for polyQ-mediated muscle pathology across related neurodegenerative diseases.
2026-04-15 | GSE305394 | GEO
Project description:Skeletal muscle pathology is a critical but poorly understood contributor to neuromuscular degeneration in spinal and bulbar muscular atrophy (SBMA), a CAG/polyglutamine (polyQ) expansion disorder caused by mutation in the androgen receptor (AR). Using a gene-targeted SBMA mouse model, we applied single-nucleus RNA sequencing to identify a previously unrecognized, disease-specific population of skeletal muscle myonuclei that replace normal myonuclear subtypes. This transition was driven by dysregulation of the PGC-1α pathway, a central regulator of myofiber specification and metabolic identity. PGC-1α dysfunction in SBMA muscle was age-, hormone-, and polyQ length–dependent and was partially rescued by subcutaneous delivery of AR-targeted antisense oligonucleotides. Integrated ChIP-seq and RNA-seq analyses revealed that aberrant PGC-1α activity promoted the expression of a distinct set of myofiber specification genes while downregulating those defining healthy Type IIb and Type IIx myonuclei. We propose a model in which this dysfunction arose downstream of polyQ-mediated sequestration of PGC-1α cofactors MEF2, CREB, and CBP, leading to transcriptional reprogramming and cellular dysfunction. These findings implicate PGC-1α dysregulation as a key event linking AR polyQ expansion to skeletal muscle degeneration and suggest a shared mechanism for polyQ-mediated muscle pathology across related neurodegenerative diseases.
2026-04-15 | GSE305396 | GEO
Project description:Skeletal muscle pathology is a critical but poorly understood contributor to neuromuscular degeneration in spinal and bulbar muscular atrophy (SBMA), a CAG/polyglutamine (polyQ) expansion disorder caused by mutation in the androgen receptor (AR). Using a gene-targeted SBMA mouse model, we applied single-nucleus RNA sequencing to identify a previously unrecognized, disease-specific population of skeletal muscle myonuclei that replace normal myonuclear subtypes. This transition was driven by dysregulation of the PGC-1α pathway, a central regulator of myofiber specification and metabolic identity. PGC-1α dysfunction in SBMA muscle was age-, hormone-, and polyQ length–dependent and was partially rescued by subcutaneous delivery of AR-targeted antisense oligonucleotides. Integrated ChIP-seq and RNA-seq analyses revealed that aberrant PGC-1α activity promoted the expression of a distinct set of myofiber specification genes while downregulating those defining healthy Type IIb and Type IIx myonuclei. We propose a model in which this dysfunction arose downstream of polyQ-mediated sequestration of PGC-1α cofactors MEF2, CREB, and CBP, leading to transcriptional reprogramming and cellular dysfunction. These findings implicate PGC-1α dysregulation as a key event linking AR polyQ expansion to skeletal muscle degeneration and suggest a shared mechanism for polyQ-mediated muscle pathology across related neurodegenerative diseases.
2026-04-15 | GSE305395 | GEO
Project description:Spinal and bulbar muscular atrophy (SBMA) is a CAG/polyglutamine (polyQ) repeat expansion disorder in which the mutant androgen receptor (AR) protein triggers progressive degeneration of the neuromuscular system in men. As the misfolded polyQ AR is the proximal mediator of toxicity, therapeutic efforts have focused on targeting the mutant protein, but these prior efforts have met with limited success in SBMA patients. Here, we examine the efficacy of proteolysis targeting chimeras (PROTACs), small molecule AR degraders that rapidly and potently promote AR ubiquitination and degradation by the proteasome. We identify ARD-1676 as a PROTAC that clears polyQ AR in an over-expression system, in patient iPSC-derived induced motor neurons and skeletal muscle cells, and in a gene targeted mouse model of disease. Furthermore, we demonstrate that 24-hour treatment with ARD-1676 rescues transcriptional dysregulation in SBMA induced skeletal muscle cells. These data provide evidence of therapeutic efficacy and in vivo target engagement, establishing PROTACs as potential therapeutic agents for the treatment of SBMA.
2025-12-09 | GSE297069 | 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:Degeneration of the neuromuscular system is a characteristic feature of spinal and bulbar muscular atrophy (SBMA), a CAG/polyglutamine (polyQ) expansion disorder caused by mutation in the androgen receptor (AR). Using a gene targeted mouse model of SBMA, AR113Q mice, we demonstrate age-dependent degeneration of the neuromuscular system that initially manifests with muscle weakness and atrophy and progresses to include denervation of neuromuscular junctions and lower motor neuron soma atrophy. Using this model, we tested the hypothesis that therapeutic intervention targeting skeletal muscle during this period of disease progression arrests degeneration of the neuromuscular system. To accomplish this, AR-targeted antisense oligonucleotides were administered subcutaneously to symptomatic AR113Q mice to reduce expression of polyQ AR in peripheral tissues but not in the spinal cord. This intervention rescued muscle atrophy, neuromuscular junction innervation, lower motor neuron soma size, and survival in aged AR113Q mice. Single-nucleus RNA sequencing revealed age-dependent transcriptional changes in the AR113Q spinal cord during disease progression which were mitigated by peripheral AR gene silencing. Our findings underscore the intricate interplay between peripheral tissues and the central nervous system in SBMA and emphasize the therapeutic effectiveness of peripheral gene knockdown in symptomatic disease.
2025-08-04 | GSE300077 | GEO
Project description:Degeneration of the neuromuscular system is a characteristic feature of spinal and bulbar muscular atrophy (SBMA), a CAG/polyglutamine (polyQ) expansion disorder caused by mutation in the androgen receptor (AR). Using a gene targeted mouse model of SBMA, AR113Q mice, we demonstrate age-dependent degeneration of the neuromuscular system that initially manifests with muscle weakness and atrophy and progresses to include denervation of neuromuscular junctions and lower motor neuron soma atrophy. Using this model, we tested the hypothesis that therapeutic intervention targeting skeletal muscle during this period of disease progression arrests degeneration of the neuromuscular system. To accomplish this, AR-targeted antisense oligonucleotides were administered subcutaneously to symptomatic AR113Q mice to reduce expression of polyQ AR in peripheral tissues but not in the spinal cord. This intervention rescued muscle atrophy, neuromuscular junction innervation, lower motor neuron soma size, and survival in aged AR113Q mice. Single-nucleus RNA sequencing revealed age-dependent transcriptional changes in the AR113Q spinal cord during disease progression which were mitigated by peripheral AR gene silencing. Our findings underscore the intricate interplay between peripheral tissues and the central nervous system in SBMA and emphasize the therapeutic effectiveness of peripheral gene knockdown in symptomatic disease.
2025-07-31 | GSE264689 | GEO
Project description:Emerging evidence implicates transcriptional dyseregulation within skeletal muscle in the pathogenesis of Kennedy disease/spinal bulbar muscular atrophy (KD/SBMA). We therefore broadly characterized gene expression in skeletal muscle of three independently generated mouse models of this disorder. The mouse models included a polyglutamine expanded (polyQ) AR knock-in model (AR113Q KI), a polyQ AR transgenic model (AR97Q Tg), and a transgenic mouse which overexpresses wild type AR solely in muscle (HSA-AR Tg). We performed microarray analysis of lower hindlimb muscles taken from these three models using high density oligonucleotide arrays. Changes in gene expression relative to wild type controls were evaluated separately in each strain. We validated our results using quantitative RT-PCR. Patterns of gene expression that are common to all lines and unique to each are described. When considered globally, the degree of overlap between the three models is approximately equivalent, and several patterns of gene expression relevant to the disease process were observed. Notably, patterns of gene expression typical of loss of AR function were observed in all three models, as were alterations in genes involved in cell adhesion, energy balance, Huntington’s disease, muscle atrophy and myogenesis. By comparing patterns of gene expression in three independent models of KD/SBMA, we have been able to identify candidate genes that might mediate the core myogenic features of KD/SBMA. Keywords: Gene expression in transgenic mice and disease state analysis
2010-10-12 | GSE10190 | GEO
Project description:Emerging evidence implicates transcriptional dyseregulation within skeletal muscle in the pathogenesis of Kennedy disease/spinal bulbar muscular atrophy (KD/SBMA). We therefore broadly characterized gene expression in skeletal muscle of three independently generated mouse models of this disorder. The mouse models included a polyglutamine expanded (polyQ) AR knock-in model (AR113Q KI), a polyQ AR transgenic model (AR97Q Tg), and a transgenic mouse which overexpresses wild type AR solely in muscle (HSA-AR Tg). We performed microarray analysis of lower hindlimb muscles taken from these three models using high density oligonucleotide arrays. Changes in gene expression relative to wild type controls were evaluated separately in each strain. We validated our results using quantitative RT-PCR. Patterns of gene expression that are common to all lines and unique to each are described. When considered globally, the degree of overlap between the three models is approximately equivalent, and several patterns of gene expression relevant to the disease process were observed. Notably, patterns of gene expression typical of loss of AR function were observed in all three models, as were alterations in genes involved in cell adhesion, energy balance, Huntingtonâ??s disease, muscle atrophy and myogenesis. By comparing patterns of gene expression in three independent models of KD/SBMA, we have been able to identify candidate genes that might mediate the core myogenic features of KD/SBMA. Keywords: Gene expression in transgenic mice and disease state analysis We used microarray (38.5K oligo mouse array, which contain 35,302 of 70mer oligonucleotide probes largely derived from constitutively expressed exons and 3,482 of controls) to analyze gene expression in limb muscles of transgenic mice. Three mouse models of KD/SBMA were used: HSA-AR, AR113Q knock-in and AR97Q. HSA-AR transgenic male mice (n=5) and their WT brothers (n=8, all mice were 110-130 days of age) were used in this experiment. ARQ113-Knock In males (n=3, 3-4 months of age), and transgenic AR97Q males and WT brothers (n= 6 of each) were used in this study. For both HSA-AR and AR113Q samples, the log2 ratio of experimental samples (Cy5) and reference RNA(Cy3) was obtained, and log2 ratios from mutant samples were then subtracted from log2 ratios from WT controls. AR97Q males (Cy5) were simply compared with their WT brothers (Cy3) using a log2 ratio, rather than being first compared with reference RNA.
2010-10-12 | E-GEOD-10190 | biostudies-arrayexpress
Project description:Title: Total Skeletal Muscle PGC-1 Deficiency Uncouples Mitochondrial Derangements from Fiber Type Determination and Insulin Sensitivity Abstract: Evidence is emerging that the PGC-1 coactivators serve a critical role in skeletal muscle metabolism, function, and disease. Mice with total PGC-1 deficiency in skeletal muscle (PGC-1α-/- βf/f/MLC-Cre mice) were generated and characterized. PGC-1α-/-βf/f/MLC-Cre mice exhibit a dramatic reduction in exercise performance compared to single PGC-1α- or PGC-1β-deficient mice and wild-type controls. The exercise phenotype of the PGC-1α-/-βf/f/MLC-Cre mice was associated with a marked diminution in muscle oxidative capacity and mitochondrial structural derangements consistent with fusion/fission and biogenic defects together with rapid depletion of muscle glycogen stores during exercise. Surprisingly, the skeletal muscle fiber type profile of the PGC-1α-/-βf/f/MLCCre mice was not significantly different than the wild-type mice. Moreover, insulin sensitivity and glucose tolerance were also not altered in the PGC-1α-/-βf/f/MLC-Cre mice. Taken together, we conclude that PGC-1 coactivators are necessary for the oxidative and mitochondrial programs of skeletal muscle but are dispensable for fundamental fiber type determination and insulin sensitivity. RNA from PGC-1alpha-/- beta f/f/Mlc1fcre was obtained and gene expression pattern compared with PGC-1alpha -/-, PGC-1beta f/f, and PGC-1beta f/f/Mlc1fCre controls. Results file descriptions: 1. GSE23365_skfloxAKO_PPexcl_genesup_GEO-8-16-2010: This table contains genes that were upregulated ≥2.0 fold in gastrocnemius muscle from PGC-1alpha-/- - mice, PGC-1beta f/f/Mlc1fCre mice and PGC-1alpha-/- - beta f/f/Mlc1fCre mice. All groups are normalized to PGC-1beta f/f mice and values are expressed as mean±SEM. The column “description’ contains the gene name, and the column “ID” contains Agilent probe names. 2. GSE23365_skfloxAKO_PPexcl_genesdown_GEO-8-16-2010 This table contains genes that were downregulated ≤0.7 fold in gastrocnemius muscle from PGC-1alpha-/- - mice, PGC-1beta f/f/Mlc1fCre mice and PGC-1alpha-/- - beta f/f/Mlc1fCre mice. All groups are normalized to PGC-1beta f/f mice and values are expressed as mean±SEM. The column “description’ contains the gene name, and the column “ID” contains Agilent probe names.
2010-12-01 | E-GEOD-23365 | biostudies-arrayexpress