Biology of Adherent Cells in Microgravity

Abstract

re , and Betty V. Nusgens Why Cell Biology Research in Microgravity?It is obvious that a journey in an orbiting spacecraft induces in most astronauts (cosmonauts) a signifi cant reduction of bone mass. This is accompanied by a large redistribution of the body fl uids and oedema of the upper part of the body and various disorders of the vascular system by alteration of the balance of the body fl uids. Altered renal function and bone resorption were suggested to be responsible for an increased propensity in forming kidney stones. The immune resistance has been considered as another side effect that is potentially responsible for various diseases, infectious and other, that could affect the crew of spacecrafts.Uni -and multicellular organisms are sensitive to environmental factors, chemical and physical, that modulate their vital functions. In space fl ights, the absence of the gravity stimulus under which all organisms have developed on Earth has been claimed to alter the precise equilibrium of physiological processes that is called health. Besides the lack of gravity, several additional disturbing elements need also to be considered, among which is increased cosmic radiations as a cause of cell damage by the induction of reactive oxygen species and mutations. Psychological stress, mainly in humans, is potentially responsible for endocrine disturbances that could also modify the operational activity of the cells. In all organisms, an exchange of information between cells modulates their functions. In multicellular organisms this situation is more complex since the different types of cells and their interactions, homo -and heterotypic, are in operation. This situation can be simplifi ed by dissociating the pluricellular organs and organisms: we can consider experimentally the participation of a single cell type and each extracellular message in the complex network of intracellular signalling that precisely controls the multiple pathways required for life. This analytical approach is most suitable for pinpointing the pieces of the puzzle that could be considered as a molecular target for pharmacological intervention. Both the pathology induced by Space exploration and its counterpart on Earth will equally benefi t from these investigations.The present chapter provides an overview of some specifi c facets of cell biological research in microgravity, their complexity and the need to continuously adapt 123 Biology in Space and Life on Earth. Effects of Spacefl ight on Biological Systems. Edited by Enno Brinckmann

RhoGTPases as Key Players in Mammalian Cell Adaptation to Microgravity

“…The most likely candidates to assume the role of these structures are various elements of the cytoskeleton, the nucleus, intracellular organelles, and also certain cell surface receptors (integrins), which interact both with cytoskeletal structures and the extracellular matrix. These structures are able to sense constraints and deformations in the matrix which are caused either by a gravitational or mechanical field and convert this signal into intracellular messengers, which then give rise to a cellular response to the changes in gravity [ 21 , 27 ]. It is also noteworthy that the cytoskeleton and integrins are not the primary sensors but react in response to their regulatory proteins (controllers of polymerization/destabilization agent).…”

Modifications of Plasma Membrane Organization in Cancer Cells for Targeted Therapy

“…Both micro-and hyper-gravity was shown to affect various cellular processes such as gene expression [304,305], proliferation [306], differentiation [307][308][309][310][311][312], autophagy [310,313,314] and cell death [305,310,315]. Although the mechanism of cellular graviperception remains unclear [316,317], previous studies suggested an essential role of the cytoskeleton [305], adhesive molecules [318], and cell membrane mechanoreceptors in that process. It is known that the reorganization of cytoskeletal fibers caused by mechanical forces such as altered gravity strongly alters cell functioning [294,319,320].…”

3D Clinorotation Affects Drug Sensitivity of Human Ovarian Cancer Cells

“…There is still a considerable uncertainty in regard to the establishment of the exact mechanism of the cellular graviperception (Lambert et al 2007;Sundaresan et al 2004). However, a substantial amount of literature indicates the vital role of the cellular cytoskeleton (Xu et al 2018), along with mechanoreceptors and adhesive molecules (Rudimov and Buravkova 2016) in those processes.…”