1.
A delayed type of three-dimensional growth of human endothelial cells under simulated weightlessness
Grimm, Daniela; Infanger, Manfred; Westphal, Kriss ...
Tissue engineering. Part A,
08/2009, Letnik:
15, Številka:
8
Journal Article
Endothelial cells (ECs) form three-dimensional (3D) aggregates without any scaffold when they are exposed to microgravity simulated by a random positioning machine (RPM) but not under static ...
conditions at gravity. Here we describe a delayed type of formation of 3D structures of ECs that was initiated when ECs cultured on a desktop RPM remained adherent for the first 5 days but spread over neighboring adherent cells, forming little colonies. After 2 weeks, tube-like structures (TSs) became visible in these cultures. They included a lumen, and they elongated during another 2 weeks of culturing. The walls of these TSs consisted mainly of single-layered ECs, which had produced significantly more beta(1)-integrin, laminin, fibronectin, and alpha-tubulin than ECs simultaneously grown adhering to the culture dishes under microgravity or normal gravity. The amount of actin protein was similar in ECs incorporated in TSs and in ECs growing at gravity. The ratio of tissue inhibitor of metalloproteinases-1 to matrix metalloproteinase-2 found in the supernatants was lower at the seventh than at the 28th day of culturing. These results suggest that culturing ECs under conditions of modeled gravitational unloading represents a new technique for studying the formation of tubes that resemble vascular intimas.
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2.
Modeled gravitational unloading induced downregulation of endothelin-1 in human endothelial cells
Infanger, Manfred; Ulbrich, Claudia; Baatout, Sarah ...
Journal of cellular biochemistry,
08/2007, Letnik:
101, Številka:
6
Journal Article
Many space missions have shown that prolonged space flights may increase the risk of cardiovascular problems. Using a three‐dimensional clinostat, we investigated human endothelial EA.hy926 cells up ...
to 10 days under conditions of simulated microgravity (µg) to distinguish transient from long‐term effects of µg and 1g. Maximum expression of all selected genes occurred after 10 min of clinorotation. Gene expression (osteopontin, Fas, TGF‐β1) declined to slightly upregulated levels or rose again (caspase‐3) after the fourth day of clinorotation. Caspase‐3, Bax, and Bcl‐2 protein content was enhanced for 10 days of microgravity. In addition, long‐term accumulation of collagen type I and III and alterations of the cytoskeletal alpha‐ and beta‐tubulins and F‐actin were detectable. A significantly reduced release of soluble factors in simulated microgravity was measured for brain‐derived neurotrophic factor, tissue factor, vascular endothelial growth factor (VEGF), and interestingly for endothelin‐1, which is important in keeping cardiovascular balances. The gene expression of endothelin‐1 was suppressed under µg conditions at days 7 and 10. Alterations of the vascular endothelium together with a decreased release of endothelin‐1 may entail post‐flight health hazards for astronauts. J. Cell. Biochem. J. Cell. Biochem. 101: 1439–1455, 2007. © 2007 Wiley‐Liss, Inc.
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3.
Effects of basic fibroblast growth factor on endothelial cells under conditions of simulated microgravity
Ulbrich, Claudia; Westphal, Kriss; Baatout, Sarah ...
Journal of cellular biochemistry,
07/2008, Letnik:
104, Številka:
4
Journal Article
Fibroblast growth factors interact with appropriate endothelial cell (EC) surface receptors and initiate intracellular signal cascades, which participate in modulating blood vessel growth. EC, upon ...
exposure to basic fibroblast growth factors (bFGFs) undergo profound functional alterations, which depend on their actual sensitivity and involve gene expression and de novo protein synthesis. We investigated the effects of bFGF on signaling pathways of EA.hy926 cells in different environments. EC were cultured under normal gravity (1 g) and simulated microgravity (µg) using a three‐dimensional (3D) clinostat. Microgravity induced early and late apoptosis, extracellular matrix proteins, endothelin‐1 (ET‐1) and TGF‐β1 expression. Microgravity reduced eNOS mRNA within 24 h. Moreover, a six‐ to eightfold higher amount of IL‐6 and IL‐8 was secreted within 24 h µg. In addition, microgravity induced a duplication of NF‐kappaB p50, while p65 was quadrupled. At 1 g, bFGF application (4 h) reduced ET‐1, TGF‐β1 and eNOS gene expression. After 24 h, bFGF enhanced fibronectin, VEGF, Flk‐1, Flt‐1, the release of IL‐6, IL‐8, and TGF‐β1. Furthermore, bFGF promoted apoptosis, reduced NFkB p50, but enhanced NFkB p65. After 4 h µg, bFGF decreased TGF‐β1, eNOS, and ET‐1 gene expression. After 24 h µg, bFGF elevated fibronectin, Flk‐1 and Flt‐1 protein, and reduced IL‐6 and IL‐8 compared with vehicle treated µg cultures. In µg, bFGF enhanced NF‐KappaB p50 by 50%, Bax by 25% and attenuated p65, activation of caspase‐3 and annexin V‐positive cells. bFGF differently changes intracellular signals in ECs depending whether it is applied under microgravity or normal gravity conditions. In microgravity, bFGF contributes to protect the EC from apoptosis. J. Cell. Biochem. 104: 1324–1341, 2008. © 2008 Wiley‐Liss, Inc.
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