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京都大学 / 0048 / 新制・論文博士 / 博士(農学) / 乙第12948号 / 論農博第2820号 / 新制||農||1035(附属図書館) / 学位論文||H27||N4935(農学部図書室) / 32207 / (主査)教授 三芳 秀人, 教授 加納 健司, 教授 三上 文三 / 学位規則第4条第2項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第20418号 / 農博第2203号 / 新制||農||1047(附属図書館) / 学位論文||H29||N5039(農学部図書室) / 京都大学大学院農学研究科応用生命科学専攻 / (主査)教授 三芳 秀人, 教授 宮川 恒, 教授 森 直樹 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

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京都大学 / 新制・課程博士 / 博士(薬科学) / 甲第24555号 / 薬科博第172号 / 新制||薬科||19(附属図書館) / 京都大学大学院薬学研究科医薬創成情報科学専攻 / (主査)教授 大野 浩章, 教授 小野 正博, 教授 掛谷 秀昭 / 学位規則第4条第1項該当 / Doctor of Pharmaceutical Sciences / Kyoto University / DFAM

BACKGROUND: Mitochondrial complex I deficiency often leads to a devastating neurodegenerative disorder of childhood. In most cases, the underlying genetic defect is unknown. Recessive nuclear gene mutations, rather than mitochondrial DNA mutations, account for the majority of cases. AIM: Our aim was to identify the genetic basis of complex I deficiency in 34 patients with isolated complex I deficiency, by studying six of the 39 nuclear encoded complex I subunit genes (NDUFV1, NDUFS1, NDUFS2, NDUFS4, NDUFS7 and NDUFS8). These genes have been conserved throughout evolution and carry out essential aspects of complex I function. METHODS: RNA was extracted from patient fibroblasts and cDNA made by reverse transcription. Overlapping amplicons that together spanned the entire coding area of each gene were amplified by PCR. The genes were screened for mutations using denaturing High Performance Liquid Chromatography (dHPLC). Patient samples with abnormal dHPLC profiles underwent direct DNA sequencing. RESULTS: Novel mutations were identified in six of 34 (18%) patients with isolated complex I deficiency. Five patients had two mutations identified and one patient had a single mutation in NDUFS4 identified. All patients with mutations had a progressive encephalopathy and five out of six had Leigh syndrome or Leigh like syndrome. Mutations were found in three nuclear encoded subunit genes, NDUFV1, NDUFS2 and NDUFS4. Three novel NDUFV1 mutations were identified (R386H, K111E and P252R). The R386H mutation was found in two apparently unrelated patients. Four novel NDUFS2 mutations were identified (R221X, M292T, R333Q and IVS9+4A&ltG). The novel NDUFS4 mutation c.221delC was found in two patients - one in homozygous form and the other heterozygous. Specific genotype and phenotype correlations were not identified. CONCLUSIONS: Nuclear encoded complex I subunit gene mutations are an important contributor to the aetiology of isolated complex I deficiency in childhood. Screening of these genes is an essential part of the investigation of complex I deficiency.

Thesis (Ph.D.)--University of Alabama at Birmingham, 2009. / Title from PDF title page (viewed on Feb. 3, 2010). Includes bibliographical references.

The thesis summarizes data gathered on various components of respiratory chain of Trypanosoma brucei. Namely, NADH:ubiquinone oxidoreductase (complex I), alternative NADH:ubiquinone oxidoreductase (NDH2) and mitochondrial glycerol-3-phosphate dehydrogenase are discussed themselves and in broader context of energy metabolism. Also, a work done using RNA interference library is described.

Le NAD+ apparaît comme un régulateur majeur du fonctionnement mitochondrial. En effet, ce cofacteur régule non seulement l’activité de nombreuses enzymes impliqués dans le métabolisme énergétique (enzymes de la β-oxydation des acides gras, du cycle de Krebs) mais joue également un rôle dans la production d’espèces réactives de l’oxygène (ROS). Le NAD+ est aussi le cofacteur des sirtuines, des enzymes déacétylases régulatrices notamment du métabolisme mitochondrial. De plus, la mitochondrie est l’organite au sein duquel la concentration en NAD+ est la plus élevée (jusqu’à 70% du NAD cellulaire). Le complexe I, qui possède une activité NADH déshydrogénase, pourrait être l’un des régulateurs majeurs du rapport NADH/NAD+ mitochondrial. L’objectif de ce travail de thèse a été d’étudier le rôle du rapport NADH/NAD+ mitochondrial dans le métabolisme énergétique et l’implication du complexe I dans les pathologies mitochondriales. Nous avons mis en évidence qu’une modulation du rapport NADH/NAD+ mitochondrial (augmentation par un activateur pharmacologique ou diminution consécutive à une mutation touchant une sous-unité du complexe I, modifie de manière drastique le métabolisme énergétique notamment en activant ou inhibant la protéine SIRT3, isoforme mitochondriale des sirtuines. Le complexe I semble jouer un rôle majeur dans cette modulation. Le resveratrol, ciblant le complexe I, ainsi que le NMN, un précurseur du NAD+, permettent de restaurer ce rapport et d’améliorer ainsi le métabolisme mitochondrial. Nos résultats suggèrent donc que le rapport NADH/NAD+ pourrait être une cible thérapeutique particulièrement intéressante dans les déficits du complexe I. / NAD+ appears as a main regulator of the mitochondrial function. Indeed, this compound not only regulates the enzymatic activity of enzymes involved in energetic metabolism (fatty acid oxidation, tricarboxylic acid cycle) but is also involved in ROS production. NAD+ is also the cofactor of sirtuins, deacetylase enzymes, in particular regulating the mitochondrial function. Moreover, mitochondria sequester most of the cellular NAD+ (up to 70 %). The complex I, which possesses an NADH dehydrogenase activity, is thought to be the most important regualtor of the mitochondrial NADH/NAD+ ratio. The work presented here aimed at studying the role of the mitochondrial NADH/NAD+ ratio in mitochondrial metabolism and to test the involvement of the complex I in mitochondrial disorders. We show that a modulation of the mitochondrial NADH/NAD+ ratio (increase by a pharmacological agent or decrease in complex-I mutated fibroplasts) severely affects the mitochondrial energetic function especially by interacting with SIRT3 a mitochondrial sirtuin isoform. The NADH/NAD+ ratio is highly regulated by complex I activity. Resveratrol, which targets the complex I, as well as NMN, a NAD+ precursor, improves the mitochondrial NADH/NAD+ ratio and consequently increases the mitochondrial metabolism. Our results strongly suggest that the mitochondrial NADH/NAD+ ratio could be an interesting therapeutic target especially in complex I- deficient patients.

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