Mucus and The Mucociliary Interface: Continuity and Clearance

The airway surface liquid is a two phased system that consists of the viscoelastic mucus layer that traps inhaled particles and the periciliary layer (PCL) that facilitates ciliary beating which drives mucociliary clearance (MCC). In a myriad of obstructive pulmonary diseases, MCC is disrupted by pathologically concentrated mucus with elevated viscoelastic properties. While the importance of MCC for pulmonary function is well established, a mechanistic understanding of how mucus is assembled from secretory granules and how mucus coordinates MCC remain elusive. Our understanding of the mucociliary interface (MCI), or the boundary between the PCL and mucus layer, remains poorly defined in terms of the efficiency and mechanism of force transfer from the beating cilia to the flowing mucus layer. Additionally, there are substantial gaps in our understanding of how pathological mucus affects the MCI. Finally, recent reports highlighting non-swellable structures present in mucus (i.e., flakes) indicate that the mucus layer may not be a continuous, homogenous viscoelastic fluid, highlighting another area where we lack an understanding of mucociliary interactions.



The goal of this Research Topic of Frontiers in Physiology is to compile a multidisciplinary perspective on the fundamental nature of the mucociliary interface. We seek submissions from cell and animal-based studies, human studies, and computational and mathematical modeling studies to give this article collection a wide range of perspectives on mucus and the mucociliary interface. We are particularly interested in submissions that describe how pathological changes to the mucus layer and the presence of mucus flakes and strands/bundles affect the MCI and MCC.



We specifically seek manuscripts that address knowledge gaps pertaining to:

• Communicate of cilia motion and force generation force to a mucus layer at the MCI

• Relative motion of mucus and cilia, both vertically and in the direction of transport.

• How pathological changes to the composition and concentration of the mucus layer affect the MCI.

• Effect of acute and chronic infections on mucus layer and MCC.

• How non-swelling structures such as mucus flakes and strands are formed and affect MCC.

• How mucus structures facilitate interaction with particles or pathogens.

• How ciliated cells affect assembly of mucus structures.

• Mathematical / computational modeling of the mucociliary interface and non-swelling mucus structures.