Space flight affects motility and cytoskeletal structures in human monocyte cell line J‐111

Abstract

Certain functions of immune cells in returning astronauts are known to be altered. A dramatic depression of the mitogenic in vitro activation of human lymphocytes was observed in low gravity. T-cell activation requires the interaction of different type of immune cells as T-lymphocytes and monocytes. Cell motility based on a continuous rearrangement of the cytoskeletal network within the cell is essential for cell-cell contacts. In this investigation on the International Space Station we studied the influence of low gravity on different cytoskeletal structures in adherent monocytes and their ability to migrate. J-111 monocytes were incubated on a colloid gold substrate attached to a cover slide. Migrating cells removed the colloid gold, leaving a track recording cell motility. A severe reduction of the motility of J-111 cells was found in low gravity compared to 1g in-flight and ground controls. Cell shape appeared more contracted, whereas the control cells showed the typical morphology of migrating monocytes, i.e., elongated and with pseudopodia. A qualitative and quantitative analysis of the structures of F-actin, β-tubulin and vinculin revealed that exposure of J-111 cells to low gravity affected the distribution of the different filaments and significantly reduced the fluorescence intensity of F-actin fibers. Cell motility relies on an intact structure of different cytoskeletal elements. The highly reduced motility of monocytes in low gravity must be attributed to the observed severe disruption of the cytoskeletal structures and may be one of the reasons for the dramatic depression of the in vitro activation of human lymphocytes.

Simulated microgravity inhibits the migration of mesenchymal stem cells by remodeling actin cytoskeleton and increasing cell stiffness

“…The effect of microgravity or simulated microgravity on cell migration is not consistent among different reports. The reduced cell migration induced by microgravity or simulated microgravity correlated with a decrease of F-actin (Plett et al 2004;Li et al 2009;Meloni et al 2011), while extended expression of CXCR4 may mediate an increased BMSCs migration under simulated microgravity (Mitsuhara et al 2013). Particularly, Siamwala et al proposed that simulated microgravity perturbs actin polymerization to promote nitric oxideassociated migration of human Eahy926 cells (Siamwala et al 2010).…”

Chronic exposure to simulated space conditions predominantly affects cytoskeleton remodeling and oxidative stress response in mouse fetal fibroblasts

“…The duration of the experiment was chosen to allow cellular adaptation to the simulated microgravity environment for instance for cytoskeleton remodeling (13,14), in order to decrease the primary stress response mechanisms and to better characterize the effects of chronic exposure to these conditions. Microarrays were performed on RNA harvested from CTRL, IR, RPM and RPM and IR conditions.…”

Mechanotransduction as an Adaptation to Gravity

“…Under low gravity environment, actin stress fibers are reduced in number, length, and thickness (178, 179). Actin is often redistributed and has either a more perinuclear or more cortical localization (180, 181).…”