Multiciliated cell basal bodies align in stereotypical patterns coordinated by the apical cytoskeleton

Multiciliated cells (MCCs) are specialized epithelial cells that coordinate fluid movement through ciliary beating. This process requires precise organization of basal bodies, which anchor the cilia. While the function of MCCs in mucociliary transport is well understood, the mechanism by which basal bodies align remains unclear. Previous studies have described the structural arrangement of MCCs in the airway epithelium, but no detailed investigation has focused on the dynamic process of basal body alignment. The role of the apical cytoskeleton in this process is not well characterized. Prior research has shown that basal bodies cluster in early developmental stages, but how they transition to a linear arrangement is unknown. This gap in knowledge motivated the current study to explore the alignment mechanism using live imaging and genetic manipulation. The apical cytoskeleton’s potential role as a self-organizing system has not been tested in MCCs. Understanding this process could clarify how MCCs achieve functional coordination. This paper addresses that gap by examining the developmental dynamics of basal body organization.

The study aimed to investigate how basal bodies in multiciliated cells align during differentiation. The researchers focused on the apical cytoskeleton’s role in this process. They used live imaging to observe basal body dynamics in mouse tracheal MCCs. The goal was to determine if apical microtubules and basal feet contribute to alignment. The study also sought to identify stereotypical patterns of basal body organization. By combining imaging with genetic and pharmacological approaches, the team aimed to test the apical cytoskeleton’s involvement. The purpose was to provide a mechanistic explanation for linear basal body alignment. This work could help clarify how MCCs achieve functional coordination in mucociliary transport.

The researchers developed a high-resolution live-imaging system to track basal bodies in cultured mouse tracheal MCCs. They used green fluorescent protein-centrin2 to label basal bodies for visualization. The study included time-lapse imaging during MCC differentiation to capture dynamic changes. Double immunostaining was performed to assess basal body orientation and basal feet association. Nocodazole was applied to disrupt apical microtubules and test their role in alignment. An Odf2 mutation was used to deplete basal feet and assess their contribution. A theoretical model was constructed to simulate the alignment process. The model treated the apical cytoskeleton as a viscoelastic fluid to explain self-organization.

The study revealed four stereotypical patterns of basal body organization during MCC differentiation. These patterns transitioned from a clustered 'floret' to a linear 'alignment' configuration. Basal body orientation was confirmed using double immunostaining with basal feet markers. Nocodazole treatment disrupted apical microtubules and prevented linear alignment. Odf2 mutation reduced basal feet and also disrupted the alignment process. The theoretical model suggested that the apical cytoskeleton behaves like a viscoelastic fluid. This behavior allows basal bodies to self-organize into a linear arrangement. The findings indicate that the apical cytoskeleton is essential for proper basal body alignment.

The study demonstrates that basal bodies in MCCs adopt stereotypical patterns during differentiation. Apical microtubules and basal feet are necessary for linear alignment of basal bodies. Disruption of these structures prevents proper organization of the basal body array. The apical cytoskeleton functions as a viscoelastic fluid in this process. The model explains how self-organization occurs without external guidance. These findings suggest a mechanism for achieving coordinated ciliary beating in MCCs. The results support the idea that the apical cytoskeleton is central to basal body alignment. This work provides a framework for understanding how MCCs achieve functional coordination.