Jang Hwanseok, Kim Jongseong, Shin Jennifer H, Fredberg Jeffrey J, Park Chan Young, Park Yongdoo
Department of Biomedical Sciences, Korea University.
Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology.
J Vis Exp. 2019 Oct 13(152). doi: 10.3791/60415.
Cells change migration patterns in response to chemical stimuli, including the gradients of the stimuli. Cellular migration in the direction of a chemical gradient, known as chemotaxis, plays an important role in development, the immune response, wound healing, and cancer metastasis. While chemotaxis modulates the migration of single cells as well as collections of cells in vivo, in vitro research focuses on single-cell chemotaxis, partly due to the lack of the proper experimental tools. To fill that gap, described here is a unique experimental system that combines microfluidics and micropatterning to demonstrate the effects of chemical gradients on collective cell migration. Furthermore, traction microscopy and monolayer stress microscopy are incorporated into the system to characterize changes in cellular force on the substrate as well as between neighboring cells. As proof-of-concept, the migration of micropatterned circular islands of Madin-Darby canine kidney (MDCK) cells is tested under a gradient of hepatocyte growth factor (HGF), a known scattering factor. It is found that cells located near the higher concentration of HGF migrate faster than those on the opposite side within a cell island. Within the same island, cellular traction is similar on both sides, but intercellular stress is much lower on the side of higher HGF concentration. This novel experimental system can provide new opportunities to studying the mechanics of chemotactic migration by cellular collectives.
细胞会根据化学刺激（包括刺激物的梯度）改变迁移模式。细胞沿化学梯度方向的迁移，即趋化性，在发育、免疫反应、伤口愈合和癌症转移中起着重要作用。虽然趋化性在体内调节单个细胞以及细胞集合的迁移，但体外研究主要集中在单细胞趋化性上，部分原因是缺乏合适的实验工具。为了填补这一空白，本文描述了一种独特的实验系统，该系统结合了微流体技术和微图案化技术，以证明化学梯度对集体细胞迁移的影响。此外，将牵引显微镜和单层应力显微镜纳入该系统，以表征细胞在底物上以及相邻细胞之间的力的变化。作为概念验证，在已知的散射因子肝细胞生长因子（HGF）的梯度下，测试了Madin-Darby犬肾（MDCK）细胞的微图案化圆形岛的迁移。发现在细胞岛内，位于HGF浓度较高一侧的细胞比另一侧的细胞迁移得更快。在同一岛内，两侧的细胞牵引力相似，但在HGF浓度较高的一侧，细胞间应力要低得多。这种新颖的实验系统可以为研究细胞集体趋化迁移的力学提供新的机会。
