Modeling the Impact of Microgravity at the Cellular Level: Implications for Human Disease

Abstract

A lack of gravity experienced during space flight has been shown to have profound effects on human physiology including muscle atrophy, reductions in bone density and immune function, and endocrine disorders. At present, these physiological changes present major obstacles to long-term space missions. What is not clear is which pathophysiological disruptions reflect changes at the cellular level versus changes that occur due to the impact of weightlessness on the entire body. This review focuses on current research investigating the impact of microgravity at the cellular level including cellular morphology, proliferation, and adhesion. As direct research in space is currently cost prohibitive, we describe here the use of microgravity simulators for studies at the cellular level. Such instruments provide valuable tools for cost-effective research to better discern the impact of weightlessness on cellular function. Despite recent advances in understanding the relationship between extracellular forces and cell behavior, very little is understood about cellular biology and mechanotransduction under microgravity conditions. This review will examine recent insights into the impact of simulated microgravity on cell biology and how this technology may provide new insight into advancing our understanding of mechanically driven biology and disease.

Keywords: cytoskeletal; mechanobiology; mechanosensing; mechanotransduction; microgravity.

FIGURE 1

The morphology and physiology alterations of adherently growing cells after microgravity exposure. Cytoskeleton components of actin, microtubules and intermediate filament are displayed in inset circles. In adherent cells, microtubules form radiation arrangement near nuclear. Actin fibers anchor to cell membranes. Intermediate filament forms loose network around nuclear. Among cells under microgravity influence, the microtubules are shortened and curved. Less actin fibers but more condense intermediate filament are observed. This illustration was inspired by long-term thyroid cells culture in simulated microgravity environment (Kopp et al., 2015; Krüger et al., 2019a).