Coordination of Cilia Movements in Multi-Ciliated Cells

Abstract

Multiple motile cilia are formed at the apical surface of multi-ciliated cells in the epithelium of the oviduct or the fallopian tube, the trachea, and the ventricle of the brain. Those cilia beat unidirectionally along the tissue axis, and this provides a driving force for directed movements of ovulated oocytes, mucus, and cerebrospinal fluid in each of these organs. Furthermore, cilia movements show temporal coordination between neighboring cilia. To establish such coordination of cilia movements, cilia need to sense and respond to various cues, including the organ’s orientation and movements of neighboring cilia. In this review, we discuss the mechanisms by which cilia movements of multi-ciliated cells are coordinated, focusing on planar cell polarity and the cytoskeleton, and highlight open questions for future research.

Formation and function of multiciliated cells

“…Although newly developed motile cilia beat in random directions (Spassky and Meunier, 2017), the directions of cilia movements within each MCC are progressively aligned (the rotational polarity) and cilia movements of neighboring MCCs are also polarized along the tissue axis (tissue-level polarity; Fig. 4 B; Arata et al, 2022). Ciliary orientation is generally measured in terms of the BB orientation and the axonemal orientation, which are respectively defined by the direction from the center of the BB to the tip of the basal foot (BB orientation) and by the line connecting the CP microtubules (CP plane; Schneiter et al, 2021).…”