title: Microgravity promotes osteoclast activity in medaka fish reared at the international space station.
abstract: The bone mineral density (BMD) of astronauts decreases specifically in the weight-bearing sites during spaceflight. It seems that osteoclasts would be affected by a change in gravity; however, the molecular mechanism involved remains unclear. Here, we show that the mineral density of the pharyngeal bone and teeth region of TRAP-GFP/Osterix-DsRed double transgenic medaka fish was decreased and that osteoclasts were activated when the fish were reared for 56 days at the international space station. In addition, electron microscopy observation revealed a low degree of roundness of mitochondria in osteoclasts. In the whole transcriptome analysis, fkbp5 and ddit4 genes were strongly up-regulated in the flight group. The fish were filmed for abnormal behavior; and, interestingly, the medaka tended to become motionless in the late stage of exposure. These results reveal impaired physiological function with a change in mechanical force under microgravity, which impairment was accompanied by osteoclast activation.
authors.affiliation: Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama 226-8501, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Chatani
authors.affiliation: Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama 226-8501, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Mantoku
authors.affiliation: Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama 226-8501, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Takeyama
authors.affiliation: Section of Biostructural Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8549, Japan.
authors.forename: Dawud
authors.initials: D
authors.lastname: Abduweli
authors.affiliation: Section of Pharmacology, Department of Bio-Matrix, Graduate School, Tokyo Medical and Dental University, Tokyo 113-8549, Japan.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Sugamori
authors.affiliation: Section of Pharmacology, Department of Bio-Matrix, Graduate School, Tokyo Medical and Dental University, Tokyo 113-8549, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Aoki
authors.affiliation: Section of Pharmacology, Department of Bio-Matrix, Graduate School, Tokyo Medical and Dental University, Tokyo 113-8549, Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Ohya
authors.affiliation: Department of Science and Applications, Japan Space Forum, Tsukuba 305-8505, Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Suzuki
authors.affiliation: Department of Science and Applications, Japan Space Forum, Tsukuba 305-8505, Japan.
authors.forename: Satoko
authors.initials: S
authors.lastname: Uchida
authors.affiliation: Department of Science and Applications, Japan Space Forum, Tsukuba 305-8505, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Sakimura
authors.affiliation: Mitsubishi Heavy Industries, Ltd. Kobe 652-8585, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kono
authors.affiliation: Japan Aerospace Exploration Agency, Tsukuba 305-8505, Japan.
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Tanigaki
authors.affiliation: Japan Aerospace Exploration Agency, Tsukuba 305-8505, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Shirakawa
authors.affiliation: Section of Biostructural Science, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo 113-8549, Japan.
authors.forename: Yoshiro
authors.initials: Y
authors.lastname: Takano
authors.affiliation: Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama 226-8501, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Kudo
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D015519:Bone Density / Q000502:physiology*; D001862:Bone Resorption / Q000503:physiopathology*; D001842:Bone and Bones / Q000502:physiology; D005118:Extraterrestrial Environment; D008928:Mitochondria / Q000502:physiology; D009990:Oryzias; D010006:Osteoblasts / Q000502:physiology; D010010:Osteoclasts / Q000502:physiology*; D010012:Osteogenesis / Q000502:physiology*; D013026:Space Flight; D018531:Spacecraft; D022021:Tacrolimus Binding Proteins / Q000096:biosynthesis / Q000235:genetics; D014070:Tooth / Q000502:physiology; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics; D015854:Up-Regulation; D014893:Weightlessness; D000099159:Tacrolimus Binding Protein 5
chemical_list: D022021:Tacrolimus Binding Proteins; D014157:Transcription Factors; D000099159:Tacrolimus Binding Protein 5