Transcriptional Homeostasis of Oxidative Stress-Related Pathways in Altered Gravity

Abstract

Whereby several types of cultured cells are sensitive to gravity, the immune system belongs to the most affected systems during spaceflight. Since reactive oxygen species/reactive nitrogen species (ROS/RNS) are serving as signals of cellular homeostasis, particularly in the cells of the immune system, we investigated the immediate effect of altered gravity on the transcription of 86 genes involved in reactive oxygen species metabolism, antioxidative systems, and cellular response to oxidative stress, using parabolic flight and suborbital ballistic rocket experiments and microarray analysis. In human myelomonocytic U937 cells, we detected a rapid response of 19.8% of all of the investigated oxidative stress-related transcripts to 1.8 g of hypergravity and 1.1% to microgravity as early as after 20 s. Nearly all (97.2%) of the initially altered transcripts adapted after 75 s of hypergravity (max. 13.5 g), and 100% adapted after 5 min of microgravity. After the almost complete adaptation of initially altered transcripts, a significant second pool of differentially expressed transcripts appeared. In contrast, we detected nearly no response of oxidative stress-related transcripts in human Jurkat T cells to altered gravity. In conclusion, we assume a very well-regulated homeostasis and transcriptional stability of oxidative stress-related pathways in altered gravity in cells of the human immune system.

Rapid Cellular Perception of Gravitational Forces in Human Jurkat T Cells and Transduction into Gene Expression Regulation

“…The TEXUS-51 mission procedures have been previously described [13,14,55,56]. Briefly, three syringes were assembled into one unit.…”

“…Human Jurkat T cell culture was performed as previously described [13,14,55,56] in the ESRANGE Space Center laboratory facilities. Briefly, sterile plastic syringes were filled with 0.5 mL Jurkat cells (25 million cells).…”

“…A detailed protocol has been published previously [13,14,55,56]. In summary, the total sample volume of 1.8 mL was sheared three times by passing through a 20 G needle (B. Braun Melsungen, Melsungen, Germany).…”

“…A detailed description of RNA sample processing and microarray data analysis can be found in previous publications [13,14,55,56]. Briefly, the Affymetrix GeneChip™ Human Transcriptome Array 2.0 (Affymetrix United Kingdom Ltd., High Wycombe, UK) was used (44,699 protein coding and 22,829 non-protein coding genes).…”

Schnelle zelluläre Reaktion und Anpassung an Schwerelosigkeit

“…In unseren Studien untersuchten wir Signaltransduktionskaskaden [3,[6][7][8], Adhäsionsmoleküle [9][10][11], Stoffwechsel [11], funktionelle Parameter [12,13], Genexpressionsreaktionen [6,[14][15][16][17][18][19]…”