Ataxia with giant axonopathy in Acbd5-deficient mice halted by adeno-associated virus gene therapy

Brain. 2024 Apr 4;147(4):1457-1473. doi: 10.1093/brain/awad407.

Abstract

Acyl-CoA binding domain containing 5 (ACBD5) is a critical player in handling very long chain fatty acids (VLCFA) en route for peroxisomal β-oxidation. Mutations in ACBD5 lead to the accumulation of VLCFA and patients present retinal dystrophy, ataxia, psychomotor delay and a severe leukodystrophy. Using CRISPR/Cas9, we generated and characterized an Acbd5 Gly357* mutant allele. Gly357* mutant mice recapitulated key features of the human disorder, including reduced survival, impaired locomotion and reflexes, loss of photoreceptors, and demyelination. The ataxic presentation of Gly357* mice involved the loss of cerebellar Purkinje cells and a giant axonopathy throughout the CNS. Lipidomic studies provided evidence for the extensive lipid dysregulation caused by VLCFA accumulation. Following a proteomic survey, functional studies in neurons treated with VLCFA unravelled a deregulated cytoskeleton with reduced actin dynamics and increased neuronal filopodia. We also show that an adeno-associated virus-mediated gene delivery ameliorated the gait phenotypes and the giant axonopathy, also improving myelination and astrocyte reactivity. Collectively, we established a mouse model with significance for VLCFA-related disorders. The development of relevant neuropathological outcomes enabled the understanding of mechanisms modulated by VLCFA and the evaluation of the efficacy of preclinical therapeutic interventions.

Keywords: AAV therapy; CNS axonopathy; VLCFA; giant axons; peroxisomal β-oxidation.

MeSH terms

  • Adrenoleukodystrophy* / genetics
  • Animals
  • Ataxia
  • Dependovirus / genetics
  • Fatty Acids* / metabolism
  • Genetic Therapy
  • Humans
  • Mice
  • Proteomics

Substances

  • Fatty Acids