Impaired NHEJ repair in amyotrophic lateral sclerosis is associated with TDP-43 mutations

Background Pathological forms of TAR DNA-binding protein 43 (TDP-43) are present in motor neurons of almost all amyotrophic lateral sclerosis (ALS) patients, and mutations in TDP-43 are also present in ALS. Loss and gain of TDP-43 functions are implicated in pathogenesis, but the mechanisms are unclear. While the RNA functions of TDP-43 have been widely investigated, its DNA binding roles remain unclear. However, recent studies have implicated a role for TDP-43 in the DNA damage response. Methods We used NSC-34 motor neuron-like cells and primary cortical neurons expressing wildtype TDP-43 or TDP-43 ALS associated mutants (A315T, Q331K), in which DNA damage was induced by etoposide or $ H_{2} $$ O_{2} $ treatment. We investigated the consequences of depletion of TDP-43 on DNA repair using small interfering RNAs. Specific non homologous end joining (NHEJ) reporters (EJ5GFP and EJ2GFP) and cells lacking DNA-dependent serine/threonine protein kinase (DNA-PK) were used to investigate the role of TDP-43 in DNA repair. To investigate the recruitment of TDP-43 to sites of DNA damage we used single molecule super-resolution microscopy and a co-immunoprecipitation assay. We also investigated DNA damage in an ALS transgenic mouse model, in which TDP-43 accumulates pathologically in the cytoplasm. We also examined fibroblasts derived from ALS patients bearing the TDP-43 M337V mutation for evidence of DNA damage. Results We demonstrate that wildtype TDP-43 is recruited to sites of DNA damage where it participates in classical NHEJ DNA repair. However, ALS-associated TDP-43 mutants lose this activity, which induces DNA damage. Furthermore, DNA damage is present in mice displaying TDP-43 pathology, implying an active role in neurodegeneration. Additionally, DNA damage triggers features typical of TDP-43 pathology; cytoplasmic mis-localisation and stress granule formation. Similarly, inhibition of NHEJ induces TDP-43 mis-localisation to the cytoplasm. Conclusions This study reveals that TDP-43 functions in DNA repair, but loss of this function triggers DNA damage and is associated with key pathological features of ALS..

Medienart:

E-Artikel

Erscheinungsjahr:

2020

Erschienen:

2020

Enthalten in:

Zur Gesamtaufnahme - volume:15

Enthalten in:

Molecular neurodegeneration - 15(2020), 1 vom: 09. Sept.

Sprache:

Englisch

Beteiligte Personen:

Konopka, Anna [VerfasserIn]
Whelan, Donna R. [VerfasserIn]
Jamali, Md Shafi [VerfasserIn]
Perri, Emma [VerfasserIn]
Shahheydari, Hamideh [VerfasserIn]
Toth, Reka P. [VerfasserIn]
Parakh, Sonam [VerfasserIn]
Robinson, Tina [VerfasserIn]
Cheong, Alison [VerfasserIn]
Mehta, Prachi [VerfasserIn]
Vidal, Marta [VerfasserIn]
Ragagnin, Audrey M. G. [VerfasserIn]
Khizhnyak, Ivan [VerfasserIn]
Jagaraj, Cyril J. [VerfasserIn]
Galper, Jasmin [VerfasserIn]
Grima, Natalie [VerfasserIn]
Deva, Anand [VerfasserIn]
Shadfar, Sina [VerfasserIn]
Nicholson, Garth A. [VerfasserIn]
Yang, Shu [VerfasserIn]
Cutts, Suzanne M. [VerfasserIn]
Horejsi, Zuzana [VerfasserIn]
Bell, Toby D. M. [VerfasserIn]
Walker, Adam K. [VerfasserIn]
Blair, Ian P. [VerfasserIn]
Atkin, Julie D. [VerfasserIn]

Links:

Volltext [kostenfrei]

Themen:

DNA damage
NHEJ
Super-resolution microscopy
TDP-43 mutations

Anmerkungen:

© The Author(s) 2020

doi:

10.1186/s13024-020-00386-4

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

OLC211936463X

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