title: Changes in mitochondrial homeostasis and redox status in astronauts following long stays in space.
abstract: The effects of long-term exposure to extreme space conditions on astronauts were investigated by analyzing hair samples from ten astronauts who had spent six months on the International Space Station (ISS). Two samples were collected before, during and after their stays in the ISS; hereafter, referred to as Preflight, Inflight and Postflight, respectively. The ratios of mitochondrial (mt) to nuclear (n) DNA and mtRNA to nRNA were analyzed via quantitative PCR. The combined data of Preflight, Inflight and Postflight show a significant reduction in the mtDNA/nDNA in Inflight, and significant reductions in the mtRNA/nRNA ratios in both the Inflight and Postflight samples. The mtRNA/mtDNA ratios were relatively constant, except in the Postflight samples. Using the same samples, the expression of redox and signal transduction related genes, MnSOD, CuZnSOD, Nrf2, Keap1, GPx4 and Catalase was also examined. The results of the combined data from Preflight, Inflight and Postflight show a significant decrease in the expression of all of the redox-related genes in the samples collected Postflight, with the exception of Catalase, which show no change. This decreased expression may contribute to increased oxidative stress Inflight resulting in the mitochondrial damage that is apparent Postflight.
authors.affiliation: Department of Oncology and Space Environmental Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima City, Kagoshima 890-8544, Japan.
authors.forename: Hiroko P
authors.initials: HP
authors.lastname: Indo
authors.affiliation: Department of Oncology and Space Environmental Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima City, Kagoshima 890-8544, Japan.
authors.forename: Hideyuki J
authors.initials: HJ
authors.lastname: Majima
authors.affiliation: Divison of Aerospace Medicine, The Jikei University School of Medicine, Minato-ku, Tokyo 105-8461, Japan.|Japan Aerospace Exploration Agency, Tsukuba City, Ibaraki 305-8505, Japan.|Space Biosciences Division, NASA Ames Research Center, Moffett Field, California 94035, USA.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Terada
authors.affiliation: Department of Oncology and Space Environmental Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima City, Kagoshima 890-8544, Japan.
authors.forename: Shigeaki
authors.initials: S
authors.lastname: Suenaga
authors.affiliation: Department of Oncology and Space Environmental Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima City, Kagoshima 890-8544, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Tomita
authors.affiliation: Japan Aerospace Exploration Agency, Tsukuba City, Ibaraki 305-8505, Japan.
authors.forename: Shin
authors.initials: S
authors.lastname: Yamada
authors.affiliation: Department of Oncology and Space Environmental Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima City, Kagoshima 890-8544, Japan.|Japan Aerospace Exploration Agency, Tsukuba City, Ibaraki 305-8505, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Higashibata
authors.affiliation: Department of Oncology and Space Environmental Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima City, Kagoshima 890-8544, Japan.|Japan Aerospace Exploration Agency, Tsukuba City, Ibaraki 305-8505, Japan.|Institute of Space and Astronautical Science, Sagamihara, Kanagawa 252-5210, Japan.|Department of Space and Astronautical Science, School of Physical Sciences, SOKENDAI (The Graduate University for Advanced Studies), Sagamihara, Kanagawa 252-5210, Japan.
authors.forename: Noriaki
authors.initials: N
authors.lastname: Ishioka
authors.affiliation: Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima City, Kagoshima 890-8544, Japan.
authors.forename: Takuro
authors.initials: T
authors.lastname: Kanekura
authors.affiliation: National Center Hospital for Mental Nervous and Muscular Disorders, Kodaira, Tokyo 187-8551, Japan.
authors.forename: Ikuya
authors.initials: I
authors.lastname: Nonaka
authors.affiliation: The Heart Research Institute, 7 Eliza Street, Newtown, Sydney, 7 Eliza Street, Newtown, Sydney, NSW 2042, Australia.|Sydney Medical School, University of Sydney, Sydney, NSW 2006, Australia.
authors.forename: Clare L
authors.initials: CL
authors.lastname: Hawkins
authors.affiliation: Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Blegdamsvej 3, Copenhagen 2200, Denmark.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Davies
authors.affiliation: Department of Toxicology and Cancer Biology, University of Kentucky College of Medicine, Lexington, Kentucky 40536, USA.
authors.forename: Daret K St
authors.initials: DK
authors.lastname: Clair
authors.affiliation: Japan Aerospace Exploration Agency, Tsukuba City, Ibaraki 305-8505, Japan.|Tokyo University of Science, Shinjuku, Tokyo 162-0825, Japan.
authors.forename: Chiaki
authors.initials: C
authors.lastname: Mukai
mesh_terms: D018480:Astronauts; D004272:DNA, Mitochondrial / Q000235:genetics / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation; D006706:Homeostasis; D006801:Humans; D008297:Male; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism; D012313:RNA / Q000235:genetics / Q000378:metabolism; D000077278:RNA, Mitochondrial; D013026:Space Flight; D013997:Time Factors
chemical_list: D004272:DNA, Mitochondrial; D000077278:RNA, Mitochondrial; D012313:RNA