Department of Systems Biology, Harvard Medical School, Boston, MA 02115.
Proc Natl Acad Sci U S A. 2013 Dec 24;110(52):21006-11. doi: 10.1073/pnas.1317441110. Epub 2013 Dec 9.
Cells integrate multiple measurement modalities to navigate their environment. Soluble and substrate-bound chemical gradients and physical cues have all been shown to influence cell orientation and migration. Here we investigate the role of asymmetric hydraulic pressure in directional sensing. Cells confined in microchannels identified and chose a path of lower hydraulic resistance in the absence of chemical cues. In a bifurcating channel with asymmetric hydraulic resistances, this choice was preceded by the elaboration of two leading edges with a faster extension rate along the lower resistance channel. Retraction of the "losing" edge appeared to precipitate a final choice of direction. The pressure differences altering leading edge protrusion rates were small, suggesting weak force generation by leading edges. The response to the physical asymmetry was able to override a dynamically generated chemical cue. Motile cells may use this bias as a result of hydraulic resistance, or "barotaxis," in concert with chemotaxis to navigate complex environments.
细胞整合多种测量模式来导航其环境。已证明可溶性和基质结合的化学梯度以及物理线索都能影响细胞的方向和迁移。在这里，我们研究了不对称液压压力在定向感应中的作用。在没有化学线索的情况下，被限制在微通道中的细胞会识别并选择阻力较小的路径。在具有不对称液压阻力的分叉通道中，这种选择是由两个前缘的精心制作所引起的，这两个前缘沿着阻力较小的通道以更快的延伸率扩展。“失去”边缘的回缩似乎导致了最终方向的选择。改变前缘突出率的压力差很小，表明前缘产生的力很弱。对物理不对称的反应能够覆盖动态生成的化学线索。运动细胞可能会由于液压阻力（或“barotaxis”）与趋化性一起使用这种偏差来在复杂环境中导航。
