Does reduced gravity alter cellular response to ionizing radiation?

Abstract

This review addresses the purported interplay between actual or simulated weightlessness and cellular response to ionizing radiation. Although weightlessness is known to alter several cellular functions and to affect signaling pathways implicated in cell proliferation, differentiation and death, its influence on cellular radiosensitivity has so far proven elusive. Renewed controversy as to whether reduced gravity enhances long-term radiation risk is fueled by recently published data that claim either overall enhancement of genomic damage or no increase of radiation-induced clastogenicity by modeled microgravity in irradiated human cells. In elucidating this crucial aspect of space radiation protection, ground-based experiments, such as those based on rotating-wall bioreactors, will increasingly be used and represent a more reproducible alternative to in-flight experiments. These low-shear vessels also make three-dimensional cellular co-cultures possible and thus allow to study the gravisensitivity of radioresponse in a context that better mimics cell-to-cell communication and hence in vivo cellular behavior.

Simulated microgravity decreases apoptosis in fetal fibroblasts

“…It has been hypothesized that the cytoskeleton could act as a mechanosensitive element that would trigger cell signaling changes leading to differences in cell proliferation and cell death (18,20). A possible interaction between irradiation and simulated microgravity has already been investigated (21). Indeed, microgravity-induced alterations in DNA damage repair kinetics following irradiation could have dramatic consequences for cell survival, which is of Figure 1.…”

Modelled microgravity cultivation modulates N-acylhomoserine lactone production in Rhodospirillum rubrum S1H independently of cell density

“…While giving us a first glimpse of how the bacterium would react to space flight conditions, the culture conditions remained far from the actual liquid culture condition foreseen in the MELiSSA loop. Since inflight research has many limitations, this has driven the development of Earth-based systems to simulate microgravity (Manti, 2006;Marco et al, 2007).…”

Are biological effects of space radiation really altered under the microgravity environment?

“…Even if the gravity condition created by MMG is not exactly same as the actual microgravity in space, it is useful to find candidates of factors responsible for the alteration by the gravity change. Manti made a similar suggestion in his review paper published in 2006 (Manti, 2006), which stated that the rotating-wall bioreactor allows for study of the gravisensitivity of radio response in a context that better mimics cell-to-cell communication and hence in vivo cellular behavior. Indeed, the several factors were found to respond to the excess of gravity by ground-based simulation.…”