Multi-scale alignment of respiratory cilia and its relation to mucociliary function.

Autor: Schneiter M; Institute of Applied Physics, University of Bern, Sidlerstrasse 5, Switzerland; Institute of Anatomy, University of Bern, Baltzerstrasse 2, Switzerland., Halm S; Institute of Anatomy, University of Bern, Baltzerstrasse 2, Switzerland., Odriozola A; Institute of Anatomy, University of Bern, Baltzerstrasse 2, Switzerland., Mogel H; Division of Veterinary Anatomy, University of Bern, Länggassstrasse 120, Switzerland., Rička J; Institute of Applied Physics, University of Bern, Sidlerstrasse 5, Switzerland., Stoffel MH; Division of Veterinary Anatomy, University of Bern, Länggassstrasse 120, Switzerland., Zuber B; Institute of Anatomy, University of Bern, Baltzerstrasse 2, Switzerland. Electronic address: benoit.zuber@ana.unibe.ch., Frenz M; Institute of Anatomy, University of Bern, Baltzerstrasse 2, Switzerland. Electronic address: martin.frenz@iap.unibe.ch., Tschanz SA; Institute of Anatomy, University of Bern, Baltzerstrasse 2, Switzerland.
Jazyk: angličtina
Zdroj: Journal of structural biology [J Struct Biol] 2021 Mar; Vol. 213 (1), pp. 107680. Date of Electronic Publication: 2020 Dec 21.
DOI: 10.1016/j.jsb.2020.107680
Abstrakt: The tracheobronchial tree is lined by a mucociliary epithelium containing millions of multiciliated cells. Their integrated oscillatory activity continuously propels an overlying pollution-protecting mucus layer in cranial direction, leading to mucociliary clearance - the primary defence mechanism of the airways. Mucociliary transport is commonly thought to co-emerge with the collective ciliary motion pattern under appropriate geometrical and rheological conditions. Proper ciliary alignment is therefore considered essential to establish mucociliary clearance in the respiratory system. Here, we used volume electron microscopy in combination with high-speed reflection contrast microscopy in order to examine ciliary orientation and its spatial organization, as well as to measure the propagation direction of metachronal waves and the direction of mucociliary transport on bovine tracheal epithelia with reference to the tracheal long axis (TLA). Ciliary orientation is measured in terms of the basal body orientation (BBO) and the axonemal orientation (AO), which are commonly considered to coincide, both equivalently indicating the effective stroke as well as the mucociliary transport direction. Our results, however, reveal that only the AO is in line with the mucociliary transport, which was found to run along a left-handed helical trajectory, whereas the BBO was found to be aligned with the TLA. Furthermore, we show that even if ciliary orientation remains consistent between adjacent cells, ciliary orientation exhibits a gradual shift within individual cells. Together with the symplectic beating geometry, this intracellular orientational pattern could provide for the propulsion of highly viscous mucus and likely constitutes a compromise between efficiency and robustness.
(Copyright © 2020 Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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