Regulation of ICAM-1 in cells of the monocyte/macrophage system in microgravity.

Liliana E Layer,Eva Hürlimann,Hartwin Lier,Frank Engelmann,Gesine Bradacs,Cora S Thiel,Josefine Biskup,Annett Gutewort,Swantje Hauschild,Svantje Tauber,Dana Michaela Simmet ,Ines Barz,Sonja Krammer,Nadine Gölz,Christiane Raig,Claudia Dumrese,Katrin Paulsen,Daniel A Hofmaenner ,Oliver Ullrich,Stephanie Engeli,Andreas Huge,Isabell Buttron,Lisa Mutschler,Gabriela Rieder,Claudia Philpot,Felix Unverdorben

doi:10.1155/2015/538786

Abstract

Cells of the immune system are highly sensitive to altered gravity, and the monocyte as well as the macrophage function is proven to be impaired under microgravity conditions. In our study, we investigated the surface expression of ICAM-1 protein and expression of ICAM-1 mRNA in cells of the monocyte/macrophage system in microgravity during clinostat, parabolic flight, sounding rocket, and orbital experiments. In murine BV-2 microglial cells, we detected a downregulation of ICAM-1 expression in clinorotation experiments and a rapid and reversible downregulation in the microgravity phase of parabolic flight experiments. In contrast, ICAM-1 expression increased in macrophage-like differentiated human U937 cells during the microgravity phase of parabolic flights and in long-term microgravity provided by a 2D clinostat or during the orbital SIMBOX/Shenzhou-8 mission. In nondifferentiated U937 cells, no effect of microgravity on ICAM-1 expression could be observed during parabolic flight experiments. We conclude that disturbed immune function in microgravity could be a consequence of ICAM-1 modulation in the monocyte/macrophage system, which in turn could have a strong impact on the interaction with T lymphocytes and cell migration. Thus, ICAM-1 can be considered as a rapid-reacting and sustained gravity-regulated molecule in mammalian cells.

Highlights

Several limiting factors for human health and performance in microgravity have been clearly identified arising from the immune system, and substantial research activities are required in order to provide the basic information for appropriate integrated risk management
We investigated the surface expression of intercellular adhesion molecules (ICAMs)-1 protein and expression of ICAM-1 mRNA in cells of the monocyte/macrophage system in microgravity during clinostat, parabolic flight, sounding rocket, and orbital experiments
ICAM-1 expression increased in macrophage-like differentiated human U937 cells during the microgravity phase of parabolic flights and in long-term microgravity provided by a 2D clinostat or during the orbital SIMBOX/Shenzhou-8 mission

Summary

Introduction

Several limiting factors for human health and performance in microgravity have been clearly identified arising from the immune system, and substantial research activities are required in order to provide the basic information for appropriate integrated risk management. T lymphocytes as well as monocytes and macrophages are impaired severely in their functions under microgravity conditions [2,3,4]. T cell activation is severely disturbed under microgravity conditions as shown in the blood of astronauts during and after space flight [5] and in numerous in vitro experiments (reviewed by [6]). In monocytes the secretion of the cytokines IL-1, IL-6, TNF-alpha, and IL-10 is altered under microgravity conditions [7, 8]. Substantial changes in gene expression of monocytes and in gene induction associated with the differentiation of monocytes into macrophages have been observed [8]

Methods

Results

Conclusion