Physiological Responses of Jurkat Lymphocytes to Simulated Microgravity Conditions

Abstract

The presence of microgravity conditions deeply affects the human body functions at the systemic, organ and cellular levels. This study aimed to investigate the effects induced by simulated-microgravity on non-stimulated Jurkat lymphocytes, an immune cell phenotype considered as a biosensor of the body responses, in order to depict at the cellular level the effects of such a peculiar condition. Jurkat cells were grown at 1 g or on random positioning machine simulating microgravity. On these cells we performed: morphological, cell cycle and proliferation analyses using cytofluorimetric and staining protocols—intracellular Ca2+, reactive oxygen species (ROS), mitochondria membrane potential and O2− measurements using fluorescent probes—aconitase and mitochondria activity, glucose and lactate content using colorimetric assays. After the first exposure days, the cells showed a more homogeneous roundish shape, an increased proliferation rate, metabolic and detoxifying activity resulted in decreased intracellular Ca2+ and ROS. In the late exposure time, the cells adapted to the new environmental condition. Our non-activated proliferating Jurkat cells, even if responsive to altered external forces, adapted to the new environmental condition showing a healthy status. In order to define the cellular mechanism(s) triggered by microgravity, developing standardized experimental approaches and controlled cell culture and simulator conditions is strongly recommended.

Antioxidant Strategy to Prevent Simulated Microgravity-Induced Effects on Bone Osteoblasts

“…The s-microgravity was established using a desktop RPM connected to a control console through standard electrical cables (Dutch Space, Leiden, The Netherlands). The main characteristics of this apparatus were previously described [45,54,55] and the use parameters reported in the manufacturer's manual. Briefly, the RPM is a 3D clinostat whose running exerts continuous changes in orientation of the biological sample in order to minimize the gravitational force vector.…”

Changes in the Surface Expression of Intercellular Adhesion Molecule 3, the Induction of Apoptosis, and the Inhibition of Cell-Cycle Progression of Human Multidrug-Resistant Jurkat/A4 Cells Exposed to a Random Positioning Machine

“…Though our results showed a slight decrease of the expression of the ICAM-3 surface marker on the RPM group in Jurkat/A4 cells, in comparison to the control, we conclude that ICAM-3 also may be an important adhesion molecule involved in the induction of leukocyte apoptosis and the functions of cell growth behavior in microgravity conditions. As demonstrated recently, the transitory effects induced by stimulated microgravity on cell shape and proliferation are accompanied by metabolic changes that are, above all, related to mitochondrial activity [16]. The modification of external forces caused by stimulated microgravity conditions induced transient modifications in cell shape and intracellular density in Jurkat cells, accompanied by transient changes in the expression levels of some cytoskeletal proteins such as actin, tubulin, and vimentin, which are not only structural proteins but also the main functional milestones in cytoskeleton dynamics [42,43].…”

“…Most studies indicated that cells of the immune system are highly sensitive to altered gravity [16][17][18]. Jurkat cells are stable cellular models easily able to be managed, and lymphocytes can be considered as biosensors of the whole-body response and of adaptation to environmental conditions [16,28]. As reviewed by Morabito et al, shear stress during rotation, and the use of a depleted medium that cannot be renewed, impacts the outcomes of exposure lasting longer than 96 h [16].…”

“…Jurkat cells are stable cellular models easily able to be managed, and lymphocytes can be considered as biosensors of the whole-body response and of adaptation to environmental conditions [16,28]. As reviewed by Morabito et al, shear stress during rotation, and the use of a depleted medium that cannot be renewed, impacts the outcomes of exposure lasting longer than 96 h [16]. According to the results of the gene expression profile, after the first 24 h of exposure to stimulated microgravity, proliferating Jurkat cells adapted to the new environmental condition, showing a healthy status [29].…”

“…The human leukemic T-cell line Jurkat is a stable cellular model that is easily able to be managed and is sensitive to real and simulated microgravity [15][16][17][18]. The changes in the expression and secretion of genes as well as proteins involved in cancer cell proliferation, metastasis, and survival shift the cells toward a less aggressive phenotype.…”