Institute of Anatomy, Faculty of Medicine, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
Department of Machine Design, Engineering Design and Product Development, Institute of Mechanical Engineering, Otto-von-Guericke-University Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany.
Int J Mol Sci. 2020 Jan 14;21(2):514. doi: 10.3390/ijms21020514.
Cellular processes are influenced in many ways by changes in gravitational force. In previous studies, we were able to demonstrate, in various cellular systems and research platforms that reactions and adaptation processes occur very rapidly after the onset of altered gravity. In this study we systematically compared differentially expressed gene transcript clusters (TCs) in human Jurkat T cells in microgravity provided by a suborbital ballistic rocket with vector-averaged gravity (vag) provided by a 2D clinostat. Additionally, we included 9× centrifuge experiments and rigorous controls for excluding other factors of influence than gravity. We found that 11 TCs were significantly altered in 5 min of flight-induced and vector-averaged gravity. Among the annotated clusters were , , , , and . Our results revealed that less than 1% of all examined TCs show the same response in vag and flight-induced microgravity, while 38% of differentially regulated TCs identified during the hypergravity phase of the suborbital ballistic rocket flight could be verified with a 9× ground centrifuge. In the 2D clinostat system, doing one full rotation per second, vector effects of the gravitational force are only nullified if the sensing mechanism requires 1 s or longer. Due to the fact that vag with an integration period of 1 s was not able to reproduce the results obtained in flight-induced microgravity, we conclude that the initial trigger of gene expression response to microgravity requires less than 1 s reaction time. Additionally, we discovered extensive gene expression differences caused by simple handling of the cell suspension in control experiments, which underlines the need for rigorous standardization regarding mechanical forces during cell culture experiments in general.
细胞过程受到重力变化的多方面影响。在之前的研究中，我们在各种细胞系统和研究平台中证明，在改变重力作用开始后，反应和适应过程会非常迅速地发生。在这项研究中，我们系统地比较了在微重力下（由亚轨道弹道火箭提供）和在向量平均重力（由二维转台提供）下的人类 Jurkat T 细胞中差异表达的基因转录簇（TCs）。此外，我们还包括了 9×离心实验和严格的对照实验，以排除除重力以外的其他影响因素。我们发现，在 5 分钟的飞行诱导和向量平均重力作用下，有 11 个 TCs 显著改变。在注释的聚类中，包括 、 、 、 、 。我们的结果表明，在 vag 和飞行诱导的微重力下，不到 1%的所有检查 TCs 表现出相同的反应，而在亚轨道弹道火箭飞行的超重力阶段中识别的 38%差异调节 TCs 可以通过 9×地面离心机验证。在二维转台系统中，每秒做一次完整的旋转，如果重力的感应机制需要 1 秒或更长时间，那么力的向量效应才会被抵消。由于 1 秒积分期的 vag 无法复制飞行诱导的微重力中获得的结果，我们得出结论，对微重力的基因表达反应的初始触发需要不到 1 秒的反应时间。此外，我们发现控制实验中简单处理细胞悬浮液会导致广泛的基因表达差异，这强调了在一般细胞培养实验中需要严格规范机械力的必要性。
