Basal Cell Expansion Conditions Influence Differentiation and Phenotypic Outcomes in Primary Nasal Epithelia Grown at Air–Liquid Interface

Background/Objectives: Primary airway epithelia grown at air–liquid interface (ALI) are widely used to model respiratory endophenotypes and to enable individualized functional testing. However, culture conditions used to establish ALI vary considerably and may introduce selection biases. We aimed to adapt our lung explant-based ALI protocol to nasal basal cells obtained by minimally invasive brushing and to identify expansion conditions that optimize the number of primary epithelia that can be generated from nasal brushing while preserving donor-specific features.

Methods

Primary nasal basal cells from nine healthy adult donors were expanded using different protocol variations in a paired design. We systematically varied two factors during the expansion phase: (a) supplementation with Rho-associated kinase (ROCK) and SMAD pathway inhibitors and (b) a single passage prior to ALI differentiation. Outcomes included the likelihood of obtaining a well-formed, differentiated ALI epithelium and functional readouts relevant to respiratory phenotyping.