Functional and molecular defects of hiPSC-derived neurons from patients with ATM deficiency

L. Carlessi, E. Fusar Poli, G. Bechi, M. Mantegazza, B. Pascucci, L. Narciso, E. Dogliotti, C. Sala, C. Verpelli, D. Lecis, D. Delia

Research output: Contribution to journalArticle

Abstract

Loss of ataxia telangiectasia mutated (ATM) kinase, a key factor of the DNA damage response (DDR) pathway, causes the cancer predisposing and neurodegenerative syndrome ataxia-telangiectasia (A-T). To investigate the mechanisms of neurodegeneration, we have reprogrammed fibroblasts from ATM-null A-T patients and normal controls to pluripotency (human-induced pluripotent stem cells), and derived from these neural precursor cells able to terminally differentiate into post-mitotic neurons positive to >90% for β-tubulin III+/microtubule-associated protein 2+. We show that A-T neurons display similar voltage-gated potassium and sodium currents and discharges of action potentials as control neurons, but defective expression of the maturation and synaptic markers SCG10, SYP and PSD95 (postsynaptic density protein 95). A-T neurons exhibited defective repair of DNA double-strand breaks (DSBs) and repressed phosphorylation of ATM substrates (e.g., γH2AX, Smc1-S966, Kap1-S824, Chk2-T68, p53-S15), but normal repair of single-strand breaks, and normal short- and long-patch base excision repair activities. Moreover, A-T neurons were resistant to apoptosis induced by the genotoxic agents camptothecin and trabectedin, but as sensitive as controls to the oxidative agents. Most notably, A-T neurons exhibited abnormal accumulation of topoisomerase 1-DNA covalent complexes (Top1-ccs). These findings reveal that ATM deficiency impairs neuronal maturation, suppresses the response and repair of DNA DSBs, and enhances Top1-cc accumulation. Top1-cc could be a risk factor for neurodegeneration as they may interfere with transcription elongation and promote transcriptional decline.

Original languageEnglish
Article numbere1342
JournalCell Death and Disease
Volume5
Issue number7
DOIs
Publication statusPublished - 2014

    Fingerprint

ASJC Scopus subject areas

  • Cell Biology
  • Immunology
  • Cancer Research
  • Cellular and Molecular Neuroscience
  • Medicine(all)

Cite this

Carlessi, L., Poli, E. F., Bechi, G., Mantegazza, M., Pascucci, B., Narciso, L., Dogliotti, E., Sala, C., Verpelli, C., Lecis, D., & Delia, D. (2014). Functional and molecular defects of hiPSC-derived neurons from patients with ATM deficiency. Cell Death and Disease, 5(7), [e1342]. https://doi.org/10.1038/cddis.2014.310