Locally synchronized ciliary domains and tissue-scale cilia alignment underlie global metachronal wave patterns
Motile cilia are hair-like cell extensions present in multiple organs of the body. How cilia coordinate their regular beat in multiciliated epithelia to efficiently displace fluids remains elusive. Here, we propose the zebrafish nose as an accessible model system to study ciliary dynamics, due to its conserved properties with other ciliated tissues and its high availability for non-invasive imaging. We reveal that cilia are locally synchronized, and that the size of local synchronization domains increases with the viscosity of the surrounding medium. Despite this merely local synchronization, we observe global patterns of traveling metachronal waves across the multiciliated epithelium. Intriguingly, these global wave direction patterns are conserved across individual fish, but different for left and right nose, revealing a chiral asymmetry of metachronal coordination. In conclusion, we show that local synchronization together with tissue-scale cilia alignment shape global wave patterns in multiciliated epithelia.