Volume 26, Issue 8, 18 August 2023, 107375
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Increased SIRT3 combined with PARP inhibition rescues motor function of SBMA mice rights and content
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  • Peptide acetylation is elevated and SIRT3 protein and activity are diminished in SBMA

  • Increasing SIRT3 corrects TCA cycle activity in SBMA mouse quadriceps

  • PARP inhibition does not rescue reduced NAD+ in SBMA mouse skeletal muscle

  • Increased SIRT3 + PARP inhibition rescues hexokinase activity and exercise endurance


Spinal and bulbar muscular atrophy (SBMA) is a neuromuscular disease with substantial mitochondrial and metabolic dysfunctions. SBMA is caused by polyglutamine (polyQ) expansion in the androgen receptor (AR). Activating or increasing the NAD+-dependent deacetylase, SIRT3, reduced oxidative stress and death of cells modeling SBMA. However, increasing diminished SIRT3 in AR100Q mice failed to reduce acetylation of the SIRT3 target/antioxidant, SOD2, and had no effect on increased total acetylated peptides in quadriceps. Yet, overexpressing SIRT3 resulted in a trend of motor recovery, and corrected TCA cycle activity by decreasing acetylation of SIRT3 target proteins. We sought to boost blunted SIRT3 activity by replenishing diminished NAD+ with PARP inhibition. Although NAD+ was not affected, overexpressing SIRT3 with PARP inhibition fully restored hexokinase activity, correcting the glycolytic pathway in AR100Q quadriceps, and rescued motor endurance of SBMA mice. These data demonstrate that targeting metabolic anomalies can restore motor function downstream of polyQ-expanded AR.

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Biological sciences
Molecular biology
Cell biology

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