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Record 1 of 1576
Stress, and pathogen response gene expression in modeled microgravity
Author and Affiliation:
Sundaresan, Alamelu(Universities Space Research Association, Houston, TX, United States)
Pellis, Neal R.(NASA Johnson Space Center, Houston, TX, United States)
Abstract: Purpose: Immune suppression in microgravity has been well documented. With the advent of human exploration and long-term space travel, the immune system of the astronaut must be optimally maintained. It is important to investigate the expression patterns of cytokine genes, because they are directly related to immune response. Heat shock proteins (HSPs), also called stress proteins, are a group of proteins that are present in the cells of every life form. These proteins are induced when a cell responds to stressors such as heat, cold and oxygen deprivation. Microgravity is another stressor that may regulate HSPs. Heat shock proteins trigger immune response through activities that occur both inside the cell (intracellular) and outside the cell (extracellular). Knowledge about these two gene groups could lead to establishment of a blueprint of the immune response and adaptation-related genes in the microgravity environment. Methods: Human peripheral blood cells were cultured in 1g (T flask) and modeled microgravity (MMG, rotating-wall vessel) for 24 and 72 hours. Cell samples were collected and subjected to gene array analysis using the Affymetrix HG_U95 array. Data was collected and subjected to a two-way analysis of variance. The genes related to immune and stress responses were analyzed. Results and Conclusions: HSP70 was up-regulated by more than two fold in microgravity culture, while HSP90 was significantly down-regulated. HSP70 is not typically expressed in all kinds of cells, but it is expressed at high levels in stress conditions. HSP70 participates in translation, protein translocation, proteolysis and protein folding, suppressing aggregation and reactivating denatured proteins. Increased serum HSP70 levels correlate with a better outcome for heat-stroke or severe trauma patients. At the same time, elevated serum levels of HSP70 have been detected in patients with peripheral or renal vascular disease. HSP90 has been identified in the cytosol, nucleus and endoplasmic reticulum, and exists in many tissue types. HSP90 associates with actin filaments in certain conditions and aids cell motility. The down-regulation of HSP90 could lead to deleterious effects in the lymphocytes, thereby contributing to suppressed immune function in microgravity. Interleukins such as IL 1 alpha, IL11 receptor chain alpha, IL7R, and IL4R were significantly down regulated in modeled microgravity. Further analysis of the genes involved in immune response at the protein level may provide a basis for prophylactic and countermeasure strategies to augment the human immune system for space exploration.
Publication Date: Jan 01, 2006
Document ID:
20060010410
(Acquired Apr 12, 2006)
Subject Category: AEROSPACE MEDICINE
Document Type: Conference Paper
Meeting Information: 15th IAA Humans in Space Symposium; 22-26 May 2005; Graz; Austria
Meeting Sponsor: The Inst. of Adaptive and Spaceflight Physics; Graz, Austria
Financial Sponsor: NASA Johnson Space Center; Houston, TX, United States
Organization Source: NASA Johnson Space Center; Houston, TX, United States
Description: 1p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: No Copyright
NASA Terms: MICROGRAVITY; GENE EXPRESSION; ASTRONAUTS; PROTEINS; PHYSIOLOGICAL RESPONSES; PATHOGENS; INTERLEUKINS; COUNTERMEASURES; INJURIES; HEAT STROKE; SPACE EXPLORATION; THERMAL SHOCK; PATIENTS
Availability Source: Other Sources
Availability Notes: Abstract Only
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