Phenotyping ciliary dynamics and coordination in response to CFTR-modulators in Cystic Fibrosis respiratory epithelial cells

Abstract

Personalized approaches for systematically assessing ciliary beat dynamics and for drug testing would improve the challenging task of diagnosing and treating respiratory disorders. In this pilot study, we show how multiscale differential dynamic microscopy (multi-DDM) can be used to characterize collective ciliary beating in a non-biased automated manner. We use multi-DDM to assess the efficacy of different CFTR-modulating drugs in human airway epithelial cells derived from subjects with cystic fibrosis (ΔF508/ΔF508 and ∆F508/-) based on ciliary beat frequency and coordination. Similar to clinical observations, drug efficacy is variable across donors, even within the same genotype. We show how our assay can quantitatively identify the most efficient drugs for restoring ciliary beating for each individual donor. Multi-DDM provides insight into ciliary beating responses following treatment with drugs, and has application in the broader context of respiratory disease and for drug screening.

The use of biophysical approaches to understand ciliary beating

“…In these systems also the kinematic properties of the fluid (viscosity, and, if the fluid is viscoelastic, it's full rheological behaviour) are crucial. We saw clear evidence of this in experiments where the cilia frequency but also the range of coordination changed dramatically with mucus washing and drug treatment, in CF cells [43].…”

“…Our team has recently demonstrated a new video analysis technique we called multi-DDM to extract information from high frame-rate videos of cells in ALI culture [42] [43]. The basic property of cilia beating is their frequency (CBF) but a wealth of other information is present in videos of cells at ALI, and connected to the fundamental concepts and open questions introduced earlier.…”

Airway Inflammation and Host Responses in the Era of CFTR Modulators

“…Ex vivo studies have revealed direct effects of CFTR modulators on the function of neutrophils [ 69 , 109 , 124 , 125 ], macrophages [ 126 , 127 , 130 ], lymphocytes [ 131 , 132 , 133 ], epithelial cells [ 134 , 135 ], and their signalling pathways [ 124 , 128 , 132 ]. There have been additional effects of CFTR modulators demonstrating improvements in MCC including LCI, mucus plugging, and air trapping [ 117 , 121 , 122 ], as well as effects on ciliary function [ 143 ]. However, despite these findings, uncertainty remains as to whether these effects are directly attributable to modulator effects on target cells or whether they are secondary to modification of the diseased airway environment.…”

“…Timing is likely to be a key determinant of modulator effects on inflammation, as those with established bronchiectasis and embedded airway infection are likely to continue to exhibit airway inflammation. Furthermore, although CFTR modulators may improve the regenerative properties of epithelial cells and macrophages [ 143 , 144 ], there is no evidence that they can reverse existing disease or the progression of lung function decline; therefore, CFTR modulators may be most effectively utilised as a preventative strategy. This is supported by studies in the G551D-mutated CF ferret model, in which the initiation of IVA treatment in utero resulted in improved pancreatic function and growth and prevented mucus accumulation and bacterial infection in the lungs [ 145 ].…”

“…These studies show that as well as improving their primary function as airway fluid regulators, CFTR modulators also have effects on epithelial immune function with evidence that they directly downregulate inflammatory responses. The effects of CFTR modulators on airway epithelial immune function, as well as their influence on redox balance, lipid metabolism, pathogen interactions, and epithelial repair [ 138 , 139 , 140 , 141 , 142 , 143 ] warrant further evaluation given the clear effects of modulator therapy on epithelial cell fluid regulation.…”