title: Mitochondrial myopathy induces a starvation-like response.
abstract: Mitochondrial respiratory chain (RC) deficiency is among the most common causes of inherited metabolic disease, but its physiological consequences are poorly characterized. We studied the skeletal muscle gene expression profiles of mice with late-onset mitochondrial myopathy. These animals express a dominant patient mutation in the mitochondrial replicative helicase Twinkle, leading to accumulation of multiple mtDNA deletions and progressive subtle RC deficiency in the skeletal muscle. The global gene expression pattern of the mouse skeletal muscle showed induction of pathways involved in amino acid starvation response and activation of Akt signaling. Furthermore, the muscle showed induction of a fasting-related hormone, fibroblast growth factor 21 (Fgf21). This secreted regulator of lipid metabolism was also elevated in the mouse serum, and the animals showed widespread changes in their lipid metabolism: small adipocyte size, low fat content in the liver and resistance to high-fat diet. We propose that RC deficiency induces a mitochondrial stress response, with local and global changes mimicking starvation, in a normal nutritional state. These results may have important implications for understanding the metabolic consequences of mitochondrial myopathies.
authors.affiliation: Research Program of Molecular Neurology, Biomedicum-Helsinki, 00290 Helsinki, Finland.
authors.forename: Henna
authors.initials: H
authors.lastname: Tyynismaa
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Carroll
authors.forename: Nuno
authors.initials: N
authors.lastname: Raimundo
authors.forename: Sofia
authors.initials: S
authors.lastname: Ahola-Erkkilä
authors.forename: Tina
authors.initials: T
authors.lastname: Wenz
authors.forename: Heini
authors.initials: H
authors.lastname: Ruhanen
authors.forename: Kilian
authors.initials: K
authors.lastname: Guse
authors.forename: Akseli
authors.initials: A
authors.lastname: Hemminki
authors.forename: Katja E
authors.initials: KE
authors.lastname: Peltola-Mjøsund
authors.forename: Valtteri
authors.initials: V
authors.lastname: Tulkki
authors.forename: Matej
authors.initials: M
authors.lastname: Oresic
authors.forename: Carlos T
authors.initials: CT
authors.lastname: Moraes
authors.forename: Kirsi
authors.initials: K
authors.lastname: Pietiläinen
authors.forename: Iiris
authors.initials: I
authors.lastname: Hovatta
authors.forename: Anu
authors.initials: A
authors.lastname: Suomalainen
mesh_terms: D017667:Adipocytes / Q000473:pathology; D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism; D004272:DNA, Mitochondrial / Q000235:genetics* / Q000378:metabolism; D004579:Electron Transport / Q000502:physiology; D005346:Fibroblast Growth Factors / Q000235:genetics; D015870:Gene Expression; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D050356:Lipid Metabolism / Q000235:genetics; D008754:Methylenetetrahydrofolate Dehydrogenase (NADP) / Q000235:genetics; D051379:Mice; D008822:Mice, Transgenic; D008931:Mitochondria, Muscle / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D017240:Mitochondrial Myopathies / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D024101:Mitochondrial Proteins / Q000235:genetics; D018482:Muscle, Skeletal / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D017384:Sequence Deletion; D013217:Starvation / Q000235:genetics / Q000378:metabolism*; D013312:Stress, Physiological
chemical_list: D000596:Amino Acids; D004272:DNA, Mitochondrial; D024101:Mitochondrial Proteins; C414620:fibroblast growth factor 21; D005346:Fibroblast Growth Factors; D008754:Methylenetetrahydrofolate Dehydrogenase (NADP); C514862:Akt1 protein, mouse; D051057:Proto-Oncogene Proteins c-akt; C513299:Twnk protein, mouse; D004265:DNA Helicases