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.