Use of in vitro cell culture models to understand the cellular and molecular basis of immune dysfunction during spaceflight

Abstract

Dysfunction of the immune system is a widely observed phenomenon in astronauts during spaceflight. To study the functional and molecular aspects of spaceflight-induced effects on immune cells, cell culture models are commonly used. While the influence of spaceflight on the immune system of the whole organism cannot be fully recapitulated by these in vitro cell culture models, they represent a highly controlled and experimentally flexible platform to investigate and understand the molecular mechanisms that might underlie in vivo immune system dysfunction. During the last 30 years, cell culture models have been used in experiments in real microgravity and in ground-based model systems that simulate aspects of microgravity such as lack of sedimentation and low fluid shear. This chapter summarizes the broad set of data that is currently available revealing that immune cells respond to the microgravity environment. The cellular processes that are affected include functions as basic as intracellular signaling via proteins and transcription factors, cytoskeletal architecture, regulation of apoptosis, cytokine secretion, and oxidative burst reactions. Considering this multitude of findings, cell culture models are considered as a useful tool to understand the biological response of human cells to gravitational changes and help to elucidate the processes and mechanisms underlying in vivo immune dysfunction during spaceflight.