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Journal article

AR cooperates with SMAD4 to maintain skeletal muscle homeostasis

Abstract:

Androgens and androgen-related molecules exert a plethora of functions across different tissues, mainly through binding to the transcription factor androgen receptor (AR). Despite widespread therapeutic use and misuse of androgens as potent anabolic agents, the molecular mechanisms of this effect on skeletal muscle are currently unknown. Muscle mass in adulthood is mainly regulated by the bone morphogenetic protein (BMP) axis of the transforming growth factor (TGF)-β pathway via recruitment of mothers against decapentaplegic homolog 4 (SMAD4) protein. Here we show that, upon activation, AR forms a transcriptional complex with SMAD4 to orchestrate a muscle hypertrophy programme by modulating SMAD4 chromatin binding dynamics and enhancing its transactivation activity. We challenged this mechanism of action using spinal and bulbar muscular atrophy (SBMA) as a model of study. This adult-onset neuromuscular disease is caused by a polyglutamine expansion (polyQ) in AR and is characterized by progressive muscle weakness and atrophy secondary to a combination of lower motor neuron degeneration and primary muscle atrophy. Here we found that the presence of an elongated polyQ tract impairs AR cooperativity with SMAD4, leading to an inability to mount an effective anti-atrophy gene expression programme in skeletal muscle in response to denervation. Furthermore, adeno-associated virus, serotype 9 (AAV9)-mediated muscle-restricted delivery of BMP7 is able to rescue the muscle atrophy in SBMA mice, supporting the development of treatments able to fine-tune AR-SMAD4 transcriptional cooperativity as a promising target for SBMA and other conditions associated with muscle loss.

Publication status:
Published
Peer review status:
Peer reviewed

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Publisher copy:
10.1007/s00401-022-02428-1

Authors


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Institution:
University of Oxford
Role:
Author
More by this author
Institution:
University of Oxford
Division:
MSD
Department:
Paediatrics
Role:
Author
ORCID:
0000-0002-1238-3040
More by this author
Role:
Author
ORCID:
0000-0002-4553-7018
More by this author
Institution:
University of Oxford
Division:
MSD
Department:
Paediatrics
Role:
Author
ORCID:
0000-0002-3313-7631


Publisher:
Springer
Journal:
Acta Neuropathologica More from this journal
Volume:
143
Issue:
6
Pages:
713-731
Publication date:
2022-05-06
Acceptance date:
2022-04-27
DOI:
EISSN:
1432-0533
ISSN:
0001-6322
Pmid:
35522298


Language:
English
Keywords:
Pubs id:
1256659
Local pid:
pubs:1256659
Deposit date:
2022-11-11

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