title: Profiling the mitochondrial proteome of Leber's Hereditary Optic Neuropathy (LHON) in Thailand: down-regulation of bioenergetics and mitochondrial protein quality control pathways in fibroblasts with the 11778G>A mutation.
abstract: Leber's Hereditary Optic Neuropathy (LHON) is one of the commonest mitochondrial diseases. It causes total blindness, and predominantly affects young males. For the disease to develop, it is necessary for an individual to carry one of the primary mtDNA mutations 11778G>A, 14484T>C or 3460G>A. However these mutations are not sufficient to cause disease, and they do not explain the characteristic features of LHON such as the higher prevalence in males, incomplete penetrance, and relatively later age of onset. In order to explore the roles of nuclear encoded mitochondrial proteins in development of LHON, we applied a proteomic approach to samples from affected and unaffected individuals from 3 pedigrees and from 5 unrelated controls. Two-dimensional electrophoresis followed by MS/MS analysis in the mitochondrial lysate identified 17 proteins which were differentially expressed between LHON cases and unrelated controls, and 24 proteins which were differentially expressed between unaffected relatives and unrelated controls. The proteomic data were successfully validated by western blot analysis of 3 selected proteins. All of the proteins identified in the study were mitochondrial proteins and most of them were down regulated in 11778G>A mutant fibroblasts. These proteins included: subunits of OXPHOS enzyme complexes, proteins involved in intermediary metabolic processes, nucleoid related proteins, chaperones, cristae remodelling proteins and an anti-oxidant enzyme. The protein profiles of both the affected and unaffected 11778G>A carriers shared many features which differed from those of unrelated control group, revealing similar proteomic responses to 11778G>A mutation in both affected and unaffected individuals. Differentially expressed proteins revealed two broad groups: a cluster of bioenergetic pathway proteins and a cluster involved in protein quality control system. Defects in these systems are likely to impede the function of retinal ganglion cells, and may lead to the development of LHON in synergy with the primary mtDNA mutation.
authors.affiliation: Department of Biochemistry, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Aung Win
authors.initials: AW
authors.lastname: Tun
authors.affiliation: Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Sakdithep
authors.initials: S
authors.lastname: Chaiyarit
authors.affiliation: Department of Biochemistry, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Supannee
authors.initials: S
authors.lastname: Kaewsutthi
authors.affiliation: Department of Biochemistry, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Wanphen
authors.initials: W
authors.lastname: Katanyoo
authors.affiliation: Department of Ophthalmology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Wanicha
authors.initials: W
authors.lastname: Chuenkongkaew
authors.affiliation: Laboratory of Proteome Research, National Institute of Biomedical Innovation, Osaka, Japan.
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Kuwano
authors.affiliation: Laboratory of Proteome Research, National Institute of Biomedical Innovation, Osaka, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Tomonaga
authors.affiliation: Department of Biochemistry, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Chayanon
authors.initials: C
authors.lastname: Peerapittayamongkol
authors.affiliation: Medical Proteomics Unit, Office for Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand; Center for Research in Complex Systems Science, Mahidol University, Bangkok, Thailand.
authors.forename: Visith
authors.initials: V
authors.lastname: Thongboonkerd
authors.affiliation: Department of Biochemistry, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Patcharee
authors.initials: P
authors.lastname: Lertrit
mesh_terms: D000328:Adult; D001706:Biopsy; D015153:Blotting, Western; D016022:Case-Control Studies; D030562:Databases, Protein; D015536:Down-Regulation; D004734:Energy Metabolism; D005190:Family; D005260:Female; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation / Q000235:genetics*; D029242:Optic Atrophy, Hereditary, Leber / Q000378:metabolism*; D020543:Proteome / Q000378:metabolism*; D040901:Proteomics; D015203:Reproducibility of Results; D013347:Subcellular Fractions / Q000378:metabolism; D013785:Thailand; D055815:Young Adult
chemical_list: D024101:Mitochondrial Proteins; D020543:Proteome