Impact of Simulated Microgravity on Cytoskeleton and Viscoelastic Properties of Endothelial Cell

Abstract

This study focused on the effects of simulated microgravity (s-μg) on mechanical properties, major cytoskeleton biopolymers, and morphology of endothelial cells (ECs). The structural and functional integrity of ECs are vital to regulate vascular homeostasis and prevent atherosclerosis. Furthermore, these highly gravity sensitive cells play a key role in pathogenesis of many diseases. In this research, impacts of s-μg on mechanical behavior of human umbilical vein endothelial cells were investigated by utilizing a three-dimensional random positioning machine (3D-RPM). Results revealed a considerable drop in cell stiffness and viscosity after 24 hrs of being subjected to weightlessness. Cortical rigidity experienced relatively immediate and significant decline comparing to the stiffness of whole cell body. The cells became rounded in morphology while western blot analysis showed reduction of the main cytoskeletal components. Moreover, fluorescence staining confirmed disorganization of both actin filaments and microtubules (MTs). The results were compared statistically among test and control groups and it was concluded that s-μg led to a significant alteration in mechanical behavior of ECs due to remodeling of cell cytoskeleton.

Microgravity-Induced Alterations of Inflammation-Related Mechanotransduction in Endothelial Cells on Board SJ-10 Satellite

“…Our data demonstrate that space microgravity suppress energy metabolism, cytokine secretion and ECM expression, modulate distinctly adhesive molecule expression, induce cytoskeletal remodeling, and enhance exosome-mediated mRNA transfer ( Figure 11 ). Our results conformed several major findings demonstrated by those studies on ECs in microgravity effect simulation using clinostats, such as decreased cell-surface expression of ICAM-1 and VCAM-1 ( Grimm et al, 2010 ; Grenon et al, 2013 ), reduced release of pro-inflammatory cytokines ( Cotrupi et al, 2005 ; Grimm et al, 2010 ; Griffoni et al, 2011 ; Grenon et al, 2013 ) and disorganization of F-actin and microtubules ( Kang et al, 2011 ; Janmaleki et al, 2016 ). However, unlike the effect of simulated microgravity, space microgravity neither enhanced NO production nor induced 3D growth in the current work, indicating a different role in angiogenesis between the two approaches.…”

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

“…Fundamental work carried out by Tabony, Pochon, and Papaseit showed that while tubulin self-assembly into microtubules occurs independent of gravity, the assembly and organization of the microtubule network is gravity dependent (Papaseit et al, 2000;Tabony et al, 2002). Importantly, this gravity-dependent organization of the microtubule network has since been described in multiple cell lines during both real and simulated microgravity exposures (Vassy et al, 2001;Uva et al, 2002;Hughes-Fulford, 2003;Rosner et al, 2006;Janmaleki et al, 2016) and possibly be the result of a poorly defined microtubule organizing center (MTOC) (Lewis et al, 1998). Taken together these data highlight an important regulatory role for the microtubule network and the MTOC following exposure to a microgravity environment.…”

Simulated microgravity triggers characteristic morphology and stress response in Saccharomyces cerevisiae

“…It should be noted that similar changes were observed in mammalian cells under conditions of SMG. Human endothelial cells incubated under conditions of SMG exhibited a round cell shape with actin disorganization (Janmaleki, Pachenari, Seyedpour, Shahghadami, & Sanati‐Nezhad, ). Comparative biology of microtubule‐associated genes also revealed remarkable evolutionary coincidence.…”