TDP-43 regulates LC3ylation in neural tissue through ATG4B cryptic splicing inhibition

Acta Neuropathol. 2024 Sep 21;148(1):45. doi: 10.1007/s00401-024-02780-4.

Abstract

Amyotrophic lateral sclerosis (ALS) is an adult-onset motor neuron disease with a mean survival time of three years. The 97% of the cases have TDP-43 nuclear depletion and cytoplasmic aggregation in motor neurons. TDP-43 prevents non-conserved cryptic exon splicing in certain genes, maintaining transcript stability, including ATG4B, which is crucial for autophagosome maturation and Microtubule-associated proteins 1A/1B light chain 3B (LC3B) homeostasis. In ALS mice (G93A), Atg4b depletion worsens survival rates and autophagy function. For the first time, we observed an elevation of LC3ylation in the CNS of both ALS patients and atg4b-/- mouse spinal cords. Furthermore, LC3ylation modulates the distribution of ATG3 across membrane compartments. Antisense oligonucleotides (ASOs) targeting cryptic exon restore ATG4B mRNA in TARDBP knockdown cells. We further developed multi-target ASOs targeting TDP-43 binding sequences for a broader effect. Importantly, our ASO based in peptide-PMO conjugates show brain distribution post-IV administration, offering a non-invasive ASO-based treatment avenue for neurodegenerative diseases.

Keywords: ALS; Antisense oligonucleotides; Autophagy; Digital PCR; Post-translational modification.

MeSH terms

  • Amyotrophic Lateral Sclerosis* / genetics
  • Amyotrophic Lateral Sclerosis* / metabolism
  • Amyotrophic Lateral Sclerosis* / pathology
  • Animals
  • Autophagy / physiology
  • Autophagy-Related Proteins* / genetics
  • Autophagy-Related Proteins* / metabolism
  • Cysteine Endopeptidases* / genetics
  • Cysteine Endopeptidases* / metabolism
  • DNA-Binding Proteins* / genetics
  • DNA-Binding Proteins* / metabolism
  • Female
  • Humans
  • Male
  • Mice
  • Mice, Knockout
  • Mice, Transgenic
  • Microtubule-Associated Proteins* / genetics
  • Microtubule-Associated Proteins* / metabolism
  • Motor Neurons / metabolism
  • Motor Neurons / pathology
  • Oligonucleotides, Antisense / pharmacology
  • RNA Splicing / genetics
  • Spinal Cord / metabolism
  • Spinal Cord / pathology

Substances

  • Autophagy-Related Proteins
  • DNA-Binding Proteins
  • ATG4B protein, human
  • Microtubule-Associated Proteins
  • Cysteine Endopeptidases
  • TARDBP protein, human
  • Atg4b protein, mouse
  • Tardbp protein, mouse
  • Oligonucleotides, Antisense