title: The mixture of "ecstasy" and its metabolites impairs mitochondrial fusion/fission equilibrium and trafficking in hippocampal neurons, at in vivo relevant concentrations.
abstract: 3,4-Methylenedioxymethamphetamine (MDMA; "ecstasy") is a potentially neurotoxic recreational drug of abuse. Though the mechanisms involved are still not completely understood, formation of reactive metabolites and mitochondrial dysfunction contribute to MDMA-related neurotoxicity. Neuronal mitochondrial trafficking, and their targeting to synapses, is essential for proper neuronal function and survival, rendering neurons particularly vulnerable to mitochondrial dysfunction. Indeed, MDMA-associated disruption of Ca(2+) homeostasis and ATP depletion have been described in neurons, thus suggesting possible MDMA interference on mitochondrial dynamics. In this study, we performed real-time functional experiments of mitochondrial trafficking to explore the role of in situ mitochondrial dysfunction in MDMA's neurotoxic actions. We show that the mixture of MDMA and six of its major in vivo metabolites, each compound at 10μM, impaired mitochondrial trafficking and increased the fragmentation of axonal mitochondria in cultured hippocampal neurons. Furthermore, the overexpression of mitofusin 2 (Mfn2) or dynamin-related protein 1 (Drp1) K38A constructs almost completely rescued the trafficking deficits caused by this mixture. Finally, in hippocampal neurons overexpressing a Mfn2 mutant, Mfn2 R94Q, with impaired fusion and transport properties, it was confirmed that a dysregulation of mitochondrial fission/fusion events greatly contributed to the reported trafficking phenotype. In conclusion, our study demonstrated, for the first time, that the mixture of MDMA and its metabolites, at concentrations relevant to the in vivo scenario, impaired mitochondrial trafficking and increased mitochondrial fragmentation in hippocampal neurons, thus providing a new insight in the context of "ecstasy"-induced neuronal injury.
authors.affiliation: REQUIMTE (Rede de Química e Tecnologia), Toxicology Laboratory, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal.
authors.forename: Daniel José
authors.initials: DJ
authors.lastname: Barbosa
authors.forename: Romàn
authors.initials: R
authors.lastname: Serrat
authors.forename: Serena
authors.initials: S
authors.lastname: Mirra
authors.forename: Martí
authors.initials: M
authors.lastname: Quevedo
authors.forename: Elena Goméz
authors.initials: EG
authors.lastname: de Barreda
authors.forename: Jesús
authors.initials: J
authors.lastname: Àvila
authors.forename: Luísa Maria
authors.initials: LM
authors.lastname: Ferreira
authors.forename: Paula Sério
authors.initials: PS
authors.lastname: Branco
authors.forename: Eduarda
authors.initials: E
authors.lastname: Fernandes
authors.forename: Maria de
authors.initials: Md
authors.lastname: Lourdes Bastos
authors.forename: João Paulo
authors.initials: JP
authors.lastname: Capela
authors.forename: Eduardo
authors.initials: E
authors.lastname: Soriano
authors.forename: Félix
authors.initials: F
authors.lastname: Carvalho
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001370:Axonal Transport / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D020558:GTP Phosphohydrolases / Q000378:metabolism; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D063154:Mitochondrial Dynamics / Q000187:drug effects*; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000378:metabolism* / Q000633:toxicity*; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D020258:Neurotoxicity Syndromes / Q000209:etiology / Q000378:metabolism; D051381:Rats
chemical_list: D000255:Adenosine Triphosphate; D020558:GTP Phosphohydrolases; C488751:Mfn2 protein, mouse; D018817:N-Methyl-3,4-methylenedioxyamphetamine; D002118:Calcium
keywords: 3,4-methylenedioxymethamphetamine (MDMA; “ecstasy”); MDMA's metabolites; mitochondrial dysfunction; mitochondrial fusion/fission; mitochondrial trafficking; neurotoxicity