title: Bioenergetic defect associated with mKATP channel opening in a mouse model carrying a mitofusin 2 mutation.
abstract: Charcot-Marie-Tooth disease type 2A (CMT2A) is an autosomal dominant axonal form of peripheral neuropathy caused by mutations in the mitofusin 2 gene (MFN2), which encodes a mitochondrial outer membrane protein that promotes mitochondrial fusion. Emerging evidence also points to a role of MFN2 in the regulation of mitochondrial metabolism. To examine whether mitochondrial dysfunction is a feature of CMT2A, we used a transgenic mouse model expressing in neurons a mutated R94Q form of human MFN2 shown to induce a CMT2A phenotype. Oxygraphic and enzymatic measurements both revealed a combined defect of mitochondrial complexes II and V (40 and 30% decrease, respectively) in the brain of Tg-R94 mice, leading to a drastic decrease of ATP synthesis. These deficiencies were reversed by the mitochondrial ATP-sensitive potassium channel (mK(ATP)) inhibitor 5-hydroxydecanoate. Conversely, in controls and wild-type human MFN2 mice, the mK(ATP) activator diazoxide mimicked the deficiency observed with the R94Q mutation. The physical links between complexes II and V, previously proposed as part of mK(ATP), were reinforced in Tg-R94Q mice. Our results show that the R94Q MFN2 mutation induces a combined defect of complexes II and V linked to the opening of mK(ATP), which could participate in the pathophysiology of the disease.
authors.affiliation: Unité Mixte de Recherche Centre National de Recherche Scientifique (CNRS) 6214, Institut National de Santé et de Recherche Me´dicale (INSERM) U771, Angers, France.
authors.forename: Virginie
authors.initials: V
authors.lastname: Guillet
authors.forename: Naïg
authors.initials: N
authors.lastname: Gueguen
authors.forename: Romain
authors.initials: R
authors.lastname: Cartoni
authors.forename: Arnaud
authors.initials: A
authors.lastname: Chevrollier
authors.forename: Valérie
authors.initials: V
authors.lastname: Desquiret
authors.forename: Claire
authors.initials: C
authors.lastname: Angebault
authors.forename: Patrizia
authors.initials: P
authors.lastname: Amati-Bonneau
authors.forename: Vincent
authors.initials: V
authors.lastname: Procaccio
authors.forename: Dominique
authors.initials: D
authors.lastname: Bonneau
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Martinou
authors.forename: Pascal
authors.initials: P
authors.lastname: Reynier
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism; D002607:Charcot-Marie-Tooth Disease / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D003981:Diazoxide / Q000494:pharmacology; D020558:GTP Phosphohydrolases / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D047468:Immunoprecipitation; D054086:KATP Channels / Q000819:agonists / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000378:metabolism*
chemical_list: D054086:KATP Channels; D024101:Mitochondrial Proteins; D020558:GTP Phosphohydrolases; C488751:Mfn2 protein, mouse; D003981:Diazoxide