Abstract

During embryonic development, the orientation of motile cilia is established in part through the action of hydrodynamic forces, but a direct test of this mechanism has remained outstanding. Using multiciliated cells on the larval skin of Xenopus laevis, the role of fluid flow in development of cilia orientational polarity is investigated by a combination of live fluorescence imaging of the ciliated tissue, high-speed cilia imaging, microfluidics, and quantitative flow visualization.

First, a systematic description of the flow profile about a multiciliated cell in vivo is presented, revealing the underling mechanical forces. Second, the live response of the system to hydrodynamic forces is tested by applying an exogenous flow. At the cell scales, basal bodies increase their alignment following cell shape changes and cytoskeleton remodelling. At the tissue scale, cell flows lead to tissue shear and overall changes in cell orientation refining the alignment of ciliated cells.