title: On the mechanism underlying ethanol-induced mitochondrial dynamic disruption and autophagy response.
abstract: We have explored the mechanisms underlying ethanol-induced mitochondrial dynamics disruption and mitophagy. Ethanol increases mitochondrial fission in a concentration-dependent manner through Drp1 mitochondrial translocation and OPA1 proteolytic cleavage. ARPE-19 (a human retinal pigment epithelial cell line) cells challenged with ethanol showed mitochondrial potential disruptions mediated by alterations in mitochondrial complex IV protein level and increases in mitochondrial reactive oxygen species production. In addition, ethanol activated the canonical autophagic pathway, as denoted by autophagosome formation and autophagy regulator elements including Beclin1, ATG5-ATG12 and P-S6 kinase. Likewise, autophagy inhibition dramatically increased mitochondrial fission and cell death, whereas autophagy stimulation rendered the opposite results, placing autophagy as a cytoprotective response aimed to remove damaged mitochondria. Interestingly, although ethanol induced mitochondrial Bax translocation, this episode was associated to cell death rather than mitochondrial fission or autophagy responses. Thus, Bax required 600 mM ethanol to migrate to mitochondria, a concentration that resulted in cell death. Furthermore, mouse embryonic fibroblasts lacking this protein respond to ethanol by undergoing mitochondrial fission and autophagy but not cytotoxicity. Finally, by using the specific mitochondrial-targeted scavenger MitoQ, we revealed mitochondria as the main source of reactive oxygen species that trigger autophagy activation. These findings suggest that cells respond to ethanol activating mitochondrial fission machinery by Drp1 and OPA1 rather than bax, in a manner that stimulates cytoprotective autophagy through mitochondrial ROS.
authors.affiliation: Grupo de Neurofarmacología, Dpto. Ciencias Médicas, Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha. IDINE, Albacete, Spain; Facultad de Medicina y Odontología, Universidad Católica de Valencia ¨San Vicente Mártir¨, Valencia, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Bonet-Ponce
authors.affiliation: Grupo de Neurofarmacología, Dpto. Ciencias Médicas, Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha. IDINE, Albacete, Spain; Facultad de Medicina y Odontología, Universidad Católica de Valencia ¨San Vicente Mártir¨, Valencia, Spain.
authors.forename: Sara
authors.initials: S
authors.lastname: Saez-Atienzar
authors.affiliation: Grupo de Neurofarmacología, Dpto. Ciencias Médicas, Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha. IDINE, Albacete, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: da Casa
authors.affiliation: Facultad de Medicina y Odontología, Universidad Católica de Valencia ¨San Vicente Mártir¨, Valencia, Spain.
authors.forename: Miguel
authors.initials: M
authors.lastname: Flores-Bellver
authors.affiliation: Facultad de Medicina y Odontología, Universidad Católica de Valencia ¨San Vicente Mártir¨, Valencia, Spain.
authors.forename: Jorge M
authors.initials: JM
authors.lastname: Barcia
authors.affiliation: Facultad de Medicina y Odontología, Universidad Católica de Valencia ¨San Vicente Mártir¨, Valencia, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Sancho-Pelluz
authors.affiliation: Facultad de Medicina y Odontología, Universidad Católica de Valencia ¨San Vicente Mártir¨, Valencia, Spain.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Romero
authors.affiliation: Grupo de Neurofarmacología, Dpto. Ciencias Médicas, Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha. IDINE, Albacete, Spain.
authors.forename: Joaquín
authors.initials: J
authors.lastname: Jordan
authors.affiliation: Grupo de Neurofarmacología, Dpto. Ciencias Médicas, Facultad de Medicina de Albacete, Universidad de Castilla-La Mancha. IDINE, Albacete, Spain; Unidad de Neuropsicofarmacología Traslacional, Complejo Hospitalario Universitario de Albacete, Albacete, Spain. Electronic address: mgalindoa@sescam.jccm.es.
authors.forename: María F
authors.initials: MF
authors.lastname: Galindo
mesh_terms: D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D000071192:Autophagy-Related Protein 12; D000071187:Autophagy-Related Protein 5; D000071186:Beclin-1; D002460:Cell Line; D034281:Dynamins / Q000378:metabolism; D000431:Ethanol / Q000494:pharmacology*; D005347:Fibroblasts / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D063154:Mitochondrial Dynamics; D063306:Mitophagy; D017382:Reactive Oxygen Species / Q000378:metabolism; D055213:Retinal Pigment Epithelium / Q000166:cytology; D019893:Ribosomal Protein S6 Kinases / Q000378:metabolism; D025841:Small Ubiquitin-Related Modifier Proteins / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: C466624:ATG12 protein, human; C502778:ATG5 protein, human; D051017:Apoptosis Regulatory Proteins; D000071192:Autophagy-Related Protein 12; D000071187:Autophagy-Related Protein 5; C491997:BECN1 protein, human; D000071186:Beclin-1; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D017382:Reactive Oxygen Species; D025841:Small Ubiquitin-Related Modifier Proteins; D051028:bcl-2-Associated X Protein; D000431:Ethanol; D019893:Ribosomal Protein S6 Kinases; D020558:GTP Phosphohydrolases; C415198:OPA1 protein, human; D034281:Dynamins
keywords: Alcohol; Apoptosis; Bax; Drp-1; Oxidative stress