title: Space experiment "Cellular Responses to Radiation in Space (CellRad)": Hardware and biological system tests.
abstract: One factor contributing to the high uncertainty in radiation risk assessment for long-term space missions is the insufficient knowledge about possible interactions of radiation with other spaceflight environmental factors. Such factors, e.g. microgravity, have to be considered as possibly additive or even synergistic factors in cancerogenesis. Regarding the effects of microgravity on signal transduction, it cannot be excluded that microgravity alters the cellular response to cosmic radiation, which comprises a complex network of signaling pathways. The purpose of the experiment "Cellular Responses to Radiation in Space" (CellRad, formerly CERASP) is to study the effects of combined exposure to microgravity, radiation and general space flight conditions on mammalian cells, in particular Human Embryonic Kidney (HEK) cells that are stably transfected with different plasmids allowing monitoring of proliferation and the Nuclear Factor κB (NF-κB) pathway by means of fluorescent proteins. The cells will be seeded on ground in multiwell plate units (MPUs), transported to the ISS, and irradiated by an artificial radiation source after an adaptation period at 0 × g and 1 × g. After different incubation periods, the cells will be fixed by pumping a formaldehyde solution into the MPUs. Ground control samples will be treated in the same way. For implementation of CellRad in the Biolab on the International Space Station (ISS), tests of the hardware and the biological systems were performed. The sequence of different steps in MPU fabrication (cutting, drilling, cleaning, growth surface coating, and sterilization) was optimized in order to reach full biocompatibility. Different coatings of the foil used as growth surface revealed that coating with 0.1 mg/ml poly-D-lysine supports cell attachment better than collagen type I. The tests of prototype hardware (Science Model) proved its full functionality for automated medium change, irradiation and fixation of cells. Exposure of HEK cells to the β-rays emitted by the radiation source dose-dependently decreased cell growth and increased NF-κB activation. The signal of the fluorescent proteins after formaldehyde fixation was stable for at least six months after fixation, allowing storage of the MPUs after fixation for several months before the transport back to Earth and evaluation of the fluorescence intensity. In conclusion, these tests show the feasibility of CellRad on the ISS with the currently available transport mechanisms.
authors.affiliation: Division of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, 51147 Köln, Germany. Electronic address: christine.hellweg@dlr.de.
authors.forename: Christine E
authors.initials: CE
authors.lastname: Hellweg
authors.affiliation: Division of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, 51147 Köln, Germany.
authors.forename: Shahana
authors.initials: S
authors.lastname: Dilruba
authors.affiliation: Airbus Defence and Space GmbH, TSPOE 3 / Payloads - Life Science, 88039 Friedrichshafen, Germany.
authors.forename: Astrid
authors.initials: A
authors.lastname: Adrian
authors.affiliation: Division of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, 51147 Köln, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Feles
authors.affiliation: Division of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, 51147 Köln, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Schmitz
authors.affiliation: Division of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, 51147 Köln, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Berger
authors.affiliation: Division of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, 51147 Köln, Germany.
authors.forename: Bartos
authors.initials: B
authors.lastname: Przybyla
authors.affiliation: Airbus Defence and Space GmbH, TSPOE 3 / Payloads - Life Science, 88039 Friedrichshafen, Germany.
authors.forename: Luca
authors.initials: L
authors.lastname: Briganti
authors.affiliation: Airbus Defence and Space GmbH, TSPOE 3 / Payloads - Life Science, 88039 Friedrichshafen, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Franz
authors.affiliation: Airbus Defence and Space GmbH, TSPOE 3 / Payloads - Life Science, 88039 Friedrichshafen, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Segerer
authors.affiliation: Division of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, 51147 Köln, Germany.
authors.forename: Luis F
authors.initials: LF
authors.lastname: Spitta
authors.affiliation: Division of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, 51147 Köln, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Henschenmacher
authors.affiliation: Division of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, 51147 Köln, Germany.
authors.forename: Bikash
authors.initials: B
authors.lastname: Konda
authors.affiliation: Division of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, 51147 Köln, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Diegeler
authors.affiliation: Division of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, 51147 Köln, Germany.
authors.forename: Christa
authors.initials: C
authors.lastname: Baumstark-Khan
authors.affiliation: Universitätsklinikum Aachen, Institut für Pharmakologie und Toxikologie, Wendlingweg 2, 52074 Aachen, Germany.
authors.forename: Corinna
authors.initials: C
authors.lastname: Panitz
authors.affiliation: Division of Radiation Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Linder Höhe, 51147 Köln, Germany.
authors.forename: Günther
authors.initials: G
authors.lastname: Reitz
mesh_terms: D003359:Cosmic Radiation; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D010957:Plasmids; D011829:Radiation Dosage; D011834:Radiation Monitoring; D015398:Signal Transduction; D013026:Space Flight; D018531:Spacecraft; D014893:Weightlessness
keywords: Biocompatibility; Mammalian radiation response; Microgravity; Nuclear factor κB; Space experiment; Storage