PADIAC - PAthway DIfferent ACtivators
  1. 2010 • ISS Increments 25-26
Life Sciences:
  • Immunology and Haematology
I. Walther (1), M. Hughes-Fulford (2), P. Pippia (3), A. Cogoli (4)
ETH Eidgenössische Technische Hochschule
Swiss Federal Institute of Technology
Space Biology Group
Technoparkstrasse 1
8005 Zurich
University of California
San Francisco, CA
University of Sassari
Department of Physiological, Biochemical and Cellular Sciences
Via Muroni 25
07100 Sassari
Zero-g Tec GmbH
ETH Technopark
Technoparkstrasse 1
8005 Zurich
  • PAthway DIfferent Activators (PADIAC) will test the hypothesis that the inhibition of interleukin-2 (IL-2) receptor expression on T-cells (mature white blood cells from the thymus) in microgravity is due to a sensitivity of the CD28 (molecule required for T-Cell stimulation) co-stimulatory (crucial to the development of an effective immune response) pathway to microgravity and determine how microgravity affects the expression of genes mediated by CD28 activation.

  • PADIAC will compare the gene expression between the different activation pathways and clearly distinguish the effect of microgravity from other space flight factors by utilizing a centrifuge to deliver 1-g forces on board the ISS.
Mammalian cells subjected to conditions of simulated microgravity on ground as well as to space flight conditions are showing alterations in their structure and function. Changes in proliferation, differentiation and genetic expression have been demonstrated in several types of cells. Among the mammalian cells, the cells of the immune system, in particular, are severely affected by the space environment. Especially T-lymphocytes are altered in their activation process. Changes in growth rate, cytokine production, locomotion, gene expression and protein kinase C (PKC) distribution have been observed on Space Shuttle flights. The main objectives of this proposal are to further investigate, using several activators, the genetic expression of the co-stimulatory transduction pathway mediated by the CD28, to assess whether the IL-1 receptor is involved in the inhibition of the activation, to see if the activation is also restored in space as it is in simulated microgravity using anti-CD3/IL-2 and to determine which genes are than expressed under these special conditions.

LEUKIN - Role of interleukin-2 receptor in signal transduction and gravisensing threshold of T-lymphocytes

ISS "Astrolab" Long Duration Mission - 2006

LEUKIN - Role of Interleukin-2 receptor in signal transduction and gravisensing threshold of T-Lymphocytes
STS-107, Spacehab - 2003
PADIAC will utiliSe thirteen dedicated Type-1 Experiment Containers (EC). The experiment will be uploaded on to the Space Shuttle in passive thermal control unit to maintain the temperature above +25 degrees C to ensure good viability of the samples. Upon arrival at the ISS, the ECs are installed in the Kubik incubator, pre-warmed to +37 degrees C. Following a short pre-incubation period the experiment is started by adding activator. Samples are then fixed with RNAlaterTM at 2, 4 and 24-hour intervals after activation. Following fixation the cassettes are stowed refrigerated in the case of download within a few days of fixation. For longer on-orbit stowage (less than 2 weeks) the samples are maintained at -20 degrees C until download.
The quality of data for the 4 h samples was excellent though a few more ground studies are needed on the 4 h samples to determine signal transduction under the three methods of activation to complete the picture. The data for the 24 h samples was less striking most likely due to the the fact that the RNA from the 24 h samples was in low amount.

The data are excellent for the 4h data with changes seen in IL2Rα, Xcl2, EGR‐1, GMCSF and IFNγ for each activation. In most cases, the ConA/CD28 and the more physiological CD3/CD28 activations were comparable, confirming that all previous work with ConA/CD28 is reliable. We had thought by bypassing the IL‐2 step would eliminate the suppression of spaceflight, but that was not the case. The effectiveness of the three activations demonstrated that all three stimulations were effective suggesting that IL2 is not the only limiting factor in microgravity. These experiments help to understand immune system activation by introducing the variable of gravity. As in mathematics, the elimination of a variable many times can eventually solve the equation. Spaceflight causes changes in the ability of the T cells to respond to a simulated infection. The central hypothesis was that this effect was solely dependent on IL‐2, however, this experiment shows that IL‐2 is not the only factor.
I. Walther, P. Pippia, M.A. Meloni, F. Turrini, F. Mannu, A. Cogoli, (1998), "Simulated microgravity inhibits the genetic expression of interleukin-2 and its receptor in mitogen-activated T lymphocytes", FEBS Letters, 436, pp. 115-118.
M. Hughes-Fulford, E. Sugano, T. Schopper, C.F. Li, J.B. Boonyaratanakornkit, A. Cogoli, (2005), "Early immune response and regulation of IL-2 receptor subunits", Cell Signal, 17, 9, pp. 1111-1124.
J.B. Boonyaratanakornkit, A. Cogoli, C.F. Li, T. Schopper, P. Pippia, G. Galleri, M.A. Meloni, M. Hughes-Fulford, (2005), "Key gravity-sensitive signaling pathways drive T cell activation", FASEB Journal, 19, 14, pp. 2020-2022.
M. Hughes-Fulford, J. Boonyaratakanakornkit, T. Chang, C.F. Li, (2011), "Spaceflight alters expression of microRNA during T cell activation", The Journal of Immunology, 186, pp. 109.16.
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PADIAC hardware
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