Agrawal Akanksha, Clayton Erin L, Cavazos Courtney L, Clayton Benjamin A, Rodney George G
Department of Integrative Physiology, Baylor College of Medicine, Houston, Texas, USA.
Acta Physiol (Oxf). 2025 Jan;241(1):e14243. doi: 10.1111/apha.14243. Epub 2024 Oct 18.
Duchenne muscular dystrophy is a progressive muscle-wasting disease caused by mutations in the dystrophin gene. Despite progress in dystrophin-targeted gene therapies, it is still a fatal disease requiring novel therapeutics that can be used synergistically or alternatively to emerging gene therapy. Defective autophagy and disorganized microtubule networks contribute to dystrophic pathogenesis, yet the mechanisms by which microtubule alterations regulate autophagy remain elusive. The present study was designed to uncover possible mechanisms underpinning the role of microtubules in regulating autophagy in dystrophic mice.
Mdx mice were also supplemented with Tubastatin A, a pharmacological inhibitor of histone deacetylase 6, and pathophysiology was assessed. Mdx mice with a genetic deletion of the Nox-2 scaffolding subunit p47 were used to assess redox dependence on tubulin acetylation.
Our data show decreased acetylation of α-tubulin with enhanced histone deacetylase 6 expression. Tubastatin A increases tubulin acetylation and Q-SNARE complex formation but does not alter microtubule organization or density, indicating improved autophagosome-lysosome fusion. Tubastatin A increases the acetylation of peroxiredoxin and protects it from hyper-oxidation, hence modulating intracellular redox status in mdx mice. Tubastatin A reduces muscle damage and enhances force production. Genetic down regulation of Nox2 activity in the mdx mice promotes autophagosome maturation but not autolysosome formation.
Our data highlight that autophagy is differentially regulated by redox and acetylation in mdx mice. By improving autophagy through promoting tubulin acetylation, Tubastatin A decreases the dystrophic phenotype and improves muscle function, suggesting a great potential for clinical translation and treating dystrophic patients.
杜兴氏肌营养不良症是一种由肌营养不良蛋白基因突变引起的进行性肌肉萎缩疾病。尽管针对肌营养不良蛋白的基因治疗取得了进展，但它仍然是一种致命疾病，需要能够与新兴基因治疗协同使用或替代使用的新型治疗方法。自噬缺陷和微管网络紊乱导致营养不良的发病机制，但微管改变调节自噬的机制仍不清楚。本研究旨在揭示微管在调节营养不良小鼠自噬中作用的潜在机制。
给mdx小鼠补充组蛋白去乙酰化酶6的药理抑制剂Tubastatin A，并评估其病理生理学。使用基因缺失Nox-2支架亚基p47的mdx小鼠来评估氧化还原对微管蛋白乙酰化的依赖性。
我们的数据显示，随着组蛋白去乙酰化酶6表达增强，α-微管蛋白的乙酰化减少。Tubastatin A增加微管蛋白乙酰化和Q-SNARE复合物形成，但不改变微管组织或密度，表明自噬体-溶酶体融合得到改善。Tubastatin A增加过氧化物酶的乙酰化并保护其免受过度氧化，从而调节mdx小鼠的细胞内氧化还原状态。Tubastatin A减少肌肉损伤并增强力量产生。mdx小鼠中Nox2活性的基因下调促进自噬体成熟，但不促进自溶酶体形成。
我们的数据突出表明，mdx小鼠的自噬受氧化还原和乙酰化的差异调节。通过促进微管蛋白乙酰化来改善自噬，Tubastatin A减少营养不良表型并改善肌肉功能，提示其在临床转化和治疗营养不良患者方面具有巨大潜力。
