Physics of Life Processes, Leiden Institute of Physics, Leiden University, Leiden, the Netherlands; School of Science, Department of Physics, Technische Universität Dresden, Dresden, Germany; Life & Physical Science, Instrumentation and Life Support Laboratory, ESA/ESTEC, Noordwijk, the Netherlands.
Life & Physical Science, Instrumentation and Life Support Laboratory, ESA/ESTEC, Noordwijk, the Netherlands; Dutch Experiment Support Centre, Department of Oral and Maxillofacial Surgery/Oral Pathology, Amsterdam University Medical Centre, location VUmc & Academic Centre for Dentistry Amsterdam, Amsterdam, the Netherlands.
Biophys J. 2021 Mar 2;120(5):773-780. doi: 10.1016/j.bpj.2021.01.021.
Cells sense and react on changes of the mechanical properties of their environment and, likewise, respond to external mechanical stress applied to them. However, whether the gravitational field as overall body force modulates cellular behavior is unclear. Different studies demonstrated that micro- and hypergravity influences the shape and elasticity of cells, initiate cytoskeleton reorganization, and influence cell motility. All these cellular properties are interconnected and contribute to forces that cells apply on their surrounding microenvironment. Yet, studies that investigated changes of cell traction forces under hypergravity conditions are scarce. Here, we performed hypergravity experiments on 3T3 fibroblast cells using the large-diameter centrifuge at the European Space Agency - European Space Research and Technology Centre. Cells were exposed to hypergravity of up to 19.5 g for 16 h in both the upright and the inverted orientation with respect to the g-force vector. We observed a decrease in cellular traction forces when the gravitational field was increased up to 5.4 g, followed by an increase of traction forces for higher gravity fields up to 19.5 g independent of the orientation of the gravity vector. We attribute the switch in cellular response to shear thinning at low g-forces, followed by significant rearrangement and enforcement of the cytoskeleton at high g-forces.
细胞感知并对其环境力学特性的变化作出反应，同样，它们也会对施加在它们身上的外部机械力作出反应。然而，重力场作为整体体力是否调节细胞行为尚不清楚。不同的研究表明，微重力和超重力会影响细胞的形状和弹性，引发细胞骨架重组，并影响细胞迁移。所有这些细胞特性都是相互关联的，它们共同作用于细胞对周围微环境施加的力。然而，研究超重力条件下细胞牵引力变化的研究还很少。在这里，我们使用欧洲航天局-欧洲空间研究与技术中心的大直径离心机对 3T3 成纤维细胞进行了超重力实验。细胞在垂直和倒置两种状态下分别暴露于高达 19.5g 的超重力中长达 16 小时。我们观察到当重力场增加到 5.4g 时，细胞牵引力会减小，然后在更高的重力场下（高达 19.5g）牵引力会增加，而与重力矢量的方向无关。我们将细胞响应的转变归因于低重力场下的剪切变稀，随后在高重力场下细胞骨架的显著重排和加强。
