Key Proteins Involved in Spheroid Formation and Angiogenesis in Endothelial Cells After Long-Term Exposure to Simulated Microgravity

Abstract

Background/Aims: Cardiovascular complications are common in astronauts returning from a prolonged spaceflight. These health problems might be driven by complex modulations of gene expression and protein synthesis in endothelial cells (ECs). Studies on the influence of microgravity on phenotype, growth pattern and biological processes of ECs can help to understand these complications. Methods: We exposed ECs (EA.hy926) to a Random Positioning Machine (RPM). Proteins associated with cell structure, angiogenesis and endothelial dysfunction were investigated in distinct pools of multicellular spheroids (MCS), adherent cells (AD) and tubular structures (TS) formed after a 35-day RPM-exposure. Results: Combining morphological and molecular approaches, we found AD, MCS and TS with changes in the synthesis and release of proteins involved in three-dimensional growth. Fibronectin and monocyte chemoattractant protein-1 (MCP-1) mRNAs and protein contents were elevated along with an increased secretion of vascular endothelial growth factor (VEGF), interleukin (IL)-6, IL-8, MCP-1, intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), neutrophil gelatinase-associated lipocalin (NGAL) and regulated on activation, normal T cell expressed and secreted (RANTES) proteins in the culture supernatant as determined by multianalyte profiling technology. Together they form a network of interaction. Conclusions: These results show that a prolonged RPM-exposure of ECs induced TS and MCS formation. The factors VEGF, NGAL, IL-6, IL-8, MCP-1, VCAM-1, ICAM-1, fibronectin and RANTES seem to be affected when gravity is omitted.

Simulated Microgravity Influences VEGF, MAPK, and PAM Signaling in Prostate Cancer Cells

“…Microgravity can induce alterations in morphology, growth, and protein biosynthesis and secretion [10], depending on the responding cell type [12]. In addition, cell cultures in µg can be performed scaffold-free to engineer three-dimensional (3D) aggregates, including multicellular spheroids (MCS), tissues, and tubular structures [13][14][15]. These organoids can be used for research in space medicine [13,16] and for testing the delivery and efficacy of drugs [17].…”

Semantic Analysis of Posttranslational Modification of Proteins Accumulated in Thyroid Cancer Cells Exposed to Simulated Microgravity

“…In addition to the interactions shown in Figure 1, it has relationships to nuclear factor kappa B [25], to connective tissue growth factor, caveolin 1, and to intercellular adhesion molecule 1. All these proteins were found in earlier studies and were considered as key proteins of spheroid formation [24,38,39]. …”

Changes in the Surface Expression of Intercellular Adhesion Molecule 3, the Induction of Apoptosis, and the Inhibition of Cell-Cycle Progression of Human Multidrug-Resistant Jurkat/A4 Cells Exposed to a Random Positioning Machine

“…ICAM-1 expression was heightened in macrophage-like differentiated human U937 cells during the microgravity phase of parabolic flights and in long-term microgravity provided by a two-dimensional clinostat or during the orbital SIMBOX/Shenzhou-8 mission [32,36]. Disturbed immune function in microgravity could be a consequence of ICAM-1 modulation in the monocyte/macrophage system, which, in turn, could have a strong impact on the cells' interaction with T-lymphocytes and migration [36].…”

“…Some researchers have reported that microgravity exposure changes the morphological phenotype, cell cycle, and cell adhesion, and has an impact on cell survival that is highly dependent upon the cell type, as well as on the duration of exposure [30,31]. Long-term RPM exposure of human endothelial cells induced the formation of three-dimensional tubular structures and spheroids [32]. Previous reports have shown that simulated microgravity induced partial arrest in the G2/M-phase of the MCF-7 cells and normal murine vascular smooth muscle cells, and also slowed down the cell cycle progression of myoblasts [33].…”