Cells are particularly good at solving mazes, according to a new study, which demonstrates how they are able to navigate long and complicated routes through the body using self-generated chemoattractant gradients. These cellular abilities are demonstrated in a pair of videos that shows cells navigating a reinterpretation of the famous Hampton Court Palace hedge maze near London. Cells navigate through tissues using gradients of attractive chemicals in a process called chemotaxis. However, simple chemotaxis only provides short-range guidance. Even so, some cells traverse relatively vast distances through the human body during embryogenesis, neural development, cancer metastasis and inflammatory immune responses. The mechanisms underlying how these cells know precisely where to go through complex biological environments isn't well understood. Through a combination of computational modeling and live cell experiments, Luke Tweedy and colleagues describe how cells can find their way through the complex and branching pathways that thread throughout the human body. Tweedy et al. created miniature microfluidic mazes and observed how live Dictyostelium discoideum- a species of soil amoeba - fared at solving them. The authors found that the cells navigate best when they use "self-generated chemotaxis" to create their own attractant gradients, which allow the cells to obtain a great deal of information about their surroundings. By breaking down the local chemoattractant gradient, cells could read the diffusion of a new attractant into the surrounding area, allowing them to "see" around corners and even accurately predict the correct path at branching junctions. Tweedy et al. conclude that these self-generated gradients are crucial to many long-range cellular processes, including inflammation and germ cell migrations.
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Science