A Monoclonal Human Alveolar Epithelial Cell Line (Arlo) with Pronounced Barrier Function for Studying Drug Permeability and Viral Infections

In the development of orally inhaled drug products preclinical animal models regularly fail to predict pharmacological as well as toxicological responses in humans. Models based on human cells and tissues are potential alternatives to animal experimentation allowing for the isolation of essential processes of human biology and making them accessible in vitro. Here, the generation of a novel monoclonal cell line Arlo, derived from the polyclonal human alveolar epithelium lentivirus immortalized cell line hAELVi via single-cell printing, and its characterization as a model for the human alveolar epithelium as well as a building block for future complex in vitro models is described. Arlo is systematically compared in vitro to primary human alveolar epithelial cells (hAEpCs) as well as to the polyclonal hAELVi cell line. Arlo cells show enhanced barrier properties with high transepithelial electrical resistance (TEER) of approximate to 3000 ohm cm(2) and a potential difference (PD) of approximate to 30 mV under air-liquid interface (ALI) conditions, that can be modulated. The cells grow in a polarized monolayer and express genes relevant to barrier integrity as well as homeostasis as is observed in hAEpCs. Successful productive infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a proof-of-principle study offers an additional, attractive application of Arlo beyond biopharmaceutical experimentation.

Automated summary

The study describes a novel monoclonal cell line called Arlo, derived from a polyclonal human alveolar epithelium cell line. Arlo cells exhibit enhanced barrier properties and express genes relevant to barrier integrity and homeostasis, similar to primary human alveolar epithelial cells. Additionally, Arlo cells have been successfully infected with SARS-CoV-2, suggesting potential applications beyond biopharmaceutical experimentation.