PAthway DIfferent ACtivators (PADIAC) - 11.22.16

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ISS Science for Everyone

Science Objectives for Everyone
PAthway DIfferent Activators (PADIAC) plans to improve the knowledge of the immune system by studying T-cell (mature white blood cells from the thymus) activation in microgravity.
Science Results for Everyone
To improve our knowledge of the immune system, this investigation compared gene expression in different pathways that activate T-cells (mature white blood cells) to distinguish the effect of microgravity from other space flight factors. Researchers tested the hypothesis that inhibition of expression of a receptor known as interleukin-2 (IL-2) in microgravity is due to sensitivity to microgravity in a molecule required for T-cell stimulation. Researchers also sought to determine how microgravity affects the expression of genes controlled by that molecule. Data revealed changes in five activation pathways and suggest that IL-2 is not the only limiting factor in microgravity.

The following content was provided by Isabelle Walther, Ph.D., and is maintained in a database by the ISS Program Science Office.
Information provided courtesy of the Erasmus Experiment Archive.
Experiment Details


Principal Investigator(s)
Isabelle Walther, Ph.D., Swiss Federal Institute of Technology, Space Biology, Zurich, Switzerland

Augusto Cogoli, Ph.D., Zero-g Tec GmbH, Zurich, Switzerland
Millie Hughes-Fulford, Ph.D., University of California, San Francisco, CA, United States
Proto Pippia, Universiy of Sassari, Sassari, Italy

Swiss Federal Institute of Technology, Space Biology, Zurich, Switzerland

Sponsoring Space Agency
European Space Agency (ESA)

Sponsoring Organization
Information Pending

Research Benefits
Information Pending

ISS Expedition Duration
September 2010 - March 2011

Expeditions Assigned

Previous Missions
Information Pending

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Experiment Description

Research Overview

  • 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.

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Space Applications
Information Pending

Earth Applications
Information Pending

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Operational Requirements and Protocols
PADIAC will utilize thirteen dedicated Type-1 Experiment Containers (EC). The experiment will be uploaded on Space Shuttle in passive thermal control unit to maintain the temperature above +25 degrees C to ensure good viability of the samples. Upon arrival to ISS, the ECs are installed in the Kubik incubator, prewarmed 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.

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Decadal Survey Recommendations

Animal and Human Biology AH14
Animal and Human Biology AH15
Crosscutting Issues for Humans in the Space Environment CC2

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Results/More Information

Information Pending

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Related Websites
The information on this page is provided courtesy of the ESA Erasmus Experiment Archive.

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image PADIAC hardware, image courtesy of ESA.
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image NASA Image: ISS025E006732 - NASA astronaut Douglas H. Wheelock, Expedition 25 commander, holds up items unpacked from the Soyuz.
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