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

Abstract

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 ≈3000 Ω cm 2 and a potential difference (PD) of ≈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.

Minimum Information for Conducting and Reporting In Vitro Intracellular Infection Assays

“…25 Isolation of a monoclonal colony of the hAELVi cell line by single-cell printing resulted in the new cell line Arlo, which shows enhanced barrier properties while preserving a monolayer morphology even upon repeated passaging. 28 Another approach to improve pre-clinical validation of nanoantibiotic is to utilize human induced pluripotent stem cells (hiPSCs). By modeling human diseases, hiPSCs provide a valuable tool to understand disease progression and are useful in predicting interactions of a new material or formulation which are useful in advancing pre-clinical results obtained.…”

“…For examples, Kuehn et al generated a human alveolar epithelial lentivirus immortalized (hAELVi) cell line derived from primary cells which were virally transduced with a set of immortalizing genes . Isolation of a monoclonal colony of the hAELVi cell line by single-cell printing resulted in the new cell line Arlo, which shows enhanced barrier properties while preserving a monolayer morphology even upon repeated passaging . Another approach to improve pre-clinical validation of nanoantibiotic is to utilize human induced pluripotent stem cells (hiPSCs).…”