Chronic Alcohol Exposure Decreases 53BP1 Protein Levels Leading to a Defective DNA Repair in Cultured Primary Cortical Neurons.
Chronic alcohol consumption may cause neurodevelopmental and neurodegenerative disorders. Alcohol neurotoxicity is associated with the production of acetaldehyde and reactive oxygen species that induce oxidative DNA damage. However, the molecular mechanisms by which ethanol disturbs the DNA damage response (DDR), resulting in a defective DNA repair, remain unknown. Here, we have used cultured primary cortical neurons exposed to 50 or 100 mM ethanol for 7 days to analyze the ethanol-induced DDR. Ethanol exposure produced a dose-dependent generation of double strand breaks and the formation of DNA damage foci immunoreactive for the histone γH2AX, a DNA damage marker, and for the ubiquitylated H2A, which is involved in chromatin remodeling at DNA damage sites. Importantly, these DNA damage foci failed to recruit the protein 53BP1, a crucial DNA repair factor. This effect was associated with a drop in 53BP1 mRNA and protein levels and with an inhibition of global transcription. Moreover, ethanol-exposed neurons treated with ionizing radiation (2 Gy) also failed to recruit 53BP1 at DNA damage foci and exhibited a greater vulnerability to DNA lesions than irradiated control neurons. Our results support that defective DNA repair, mediated by the deficient expression and recruitment of 53BP1 to DNA damage sites, represents a novel mechanism involved in ethanol neurotoxicity. The design of therapeutic strategies that increase or stabilize 53BP1 levels might potentially promote DNA repair and partially compensate alcohol neurotoxicity.
Sección de Biología y Patología Celular, Centro de Investigación, Hospital La Fe, Valencia, Spain.|Unidad de Microscopía IIS La Fe, Valencia, Spain.
Ana M
AM
Romero
Department of Anatomy and Cell Biology and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)", University of Cantabria-IDIVAL, Av. Cardenal Herrera Oria s/n, 39011, Santander, Spain.
Ana
A
Palanca
Department of Anatomy and Cell Biology and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)", University of Cantabria-IDIVAL, Av. Cardenal Herrera Oria s/n, 39011, Santander, Spain.
Maria
M
Ruiz-Soto
Division of Epidemiology and Public Health, "CIBER de Epidemiología y Salud Pública (CIBERESP)", IDIVAL, University of Cantabria, Santander, Spain.
Javier
J
Llorca
Unidad de Microscopía IIS La Fe, Valencia, Spain.
María P
MP
Marín
Sección de Biología y Patología Celular, Centro de Investigación, Hospital La Fe, Valencia, Spain.
Jaime
J
Renau-Piqueras
Department of Anatomy and Cell Biology and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)", University of Cantabria-IDIVAL, Av. Cardenal Herrera Oria s/n, 39011, Santander, Spain.
Maria T
MT
Berciano
Department of Anatomy and Cell Biology and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)", University of Cantabria-IDIVAL, Av. Cardenal Herrera Oria s/n, 39011, Santander, Spain. lafargam@unican.es.
Miguel
M
Lafarga
D000818:Animals; D002492:Central Nervous System Depressants / Q000494:pharmacology*; D002540:Cerebral Cortex / Q000166:cytology*; D002843:Chromatin / Q000187:drug effects / Q000648:ultrastructure; D020552:Comet Assay; D004249:DNA Damage / Q000187:drug effects; D004260:DNA Repair / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004622:Embryo, Mammalian; D000431:Ethanol / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000528:radiation effects; D006624:Hippocampus / Q000166:cytology; D006657:Histones / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009474:Neurons / Q000187:drug effects* / Q000648:ultrastructure; D051381:Rats; D013997:Time Factors; D015533:Transcriptional Activation / Q000187:drug effects; D014965:X-Rays / Q000009:adverse effects
D002492:Central Nervous System Depressants; D002843:Chromatin; C468783:H2AX protein, human; D006657:Histones; D047908:Intracellular Signaling Peptides and Proteins; C489787:MAP2 protein, rat; D008869:Microtubule-Associated Proteins; D000431:Ethanol
53BP1; DNA damage; Defective DNA repair; Ethanol neurotoxicity; Neurodegeneration