Primary ciliary dyskinesia (PCD) is a genetically heterogeneous disorder caused by defective motile cilia, resulting in impaired mucociliary clearance, chronic respiratory disease, laterality defects and subfertility. Currently, no disease-modifying treatments exist. Targeting PCD at its root cause requires emerging genetic therapies, such as small molecules, oligonucleotides, mRNA therapy, gene replacement and genome editing. With over 52 implicated genes and numerous patient-specific variants, there is a need for robust preclinical models to evaluate and accelerate these approaches. This review examines human preclinical models that recapitulate patient-specific genotypes and phenotypes while providing sufficient scalability for screening and detailed efficacy assessment. The models should also resolve knowledge gaps, including which cells need targeting and at what stage of differentiation. Air–liquid interface cultures of primary human airway epithelial cells or induced pluripotent stem cells (iPSCs) represent the current practice, alongside three-dimensional organoids, spheroids and lung-on-a-chip platforms. To overcome the limited proliferative capacity of primary cells, strategies include BMI-1 or hTERT transduction, conditional reprogramming with Rho-associated kinase (ROCK) inhibitors and feeder layers, and differentiation of iPSCs. Patient-derived and CRISPR-edited models have been developed for multiple PCD genes. Outcome measures to confirm efficacy of the therapy include high-speed video microscopy for quantifying ciliary beat pattern, transmission electron microscopy for ultrastructural assessment, mucociliary clearance assays and deep molecular phenotyping. There is a need for field-wide standardisation through consensus protocols, core outcome sets, minimum reporting criteria, quality benchmarks and regulatory alignment to facilitate accelerated translation of preclinical findings to clinical therapeutics.
Ong et al. (Wed,) studied this question.