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: Virginie Guillet, Naïg Gueguen, Romain Cartoni, Arnaud Chevrollier, Valérie Desquiret, Claire Angebault, Patrizia Amati-Bonneau, Vincent Procaccio, Dominique Bonneau, Jean-Claude Martinou, Pascal Reynier
• Journal: FASEB journal : official publication of the Federation of American Societies for Experimental Biology (FASEB J) Vol. 25 Issue 5 Pg. 1618-27 (May 2011) ISSN: 1530-6860 [Electronic] United States
• PMID: 21285398 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• KATP Channels
• Mitochondrial Proteins
• GTP Phosphohydrolases
• Mfn2 protein, mouse
• Diazoxide

Topics

• Animals
• Blotting, Western
• Brain (metabolism)
• Charcot-Marie-Tooth Disease (genetics, metabolism, pathology)
• Diazoxide (pharmacology)
• GTP Phosphohydrolases (genetics, metabolism)
• Humans
• Immunoprecipitation
• KATP Channels (agonists, metabolism)
• Mice
• Mice, Inbred C57BL
• Mice, Transgenic
• Mitochondria (drug effects, metabolism)
• Mitochondrial Proteins (metabolism)