Intimacy is a cellular turn-on

The simple act of coming closer together ignites signaling pathways in epithelial cells, as shown by Daniel Tschumperlin, Jeffrey Drazen (Harvard School of Public Health, Boston, MA), and colleagues. The results describe how cells might activate cellular responses to mechanical stress.

Cells are pushed closer together by physical forces. In the lung, for instance, epithelial cells feel the pressure from underlying muscle tissue, particularly in asthmatic patients. The authors see that these forces do not change cellular volume. Rather, they squeeze out fluids from between neighboring cells.

The resulting close cellular proximity means that ligands that get secreted between cells are more concentrated and therefore more likely to activate signaling pathways. “Now there's less space for these things to bounce around in before they find a receptor,” says Tschumperlin.

Lung cells under...