Human organs-on-chips as tools for repurposing approved drugs as potential influenza and COVID19 therapeutics in viral pandemics

Longlong Si; Haiqing Bai; Melissa Rodas; Wuji Cao; Crystal Yur Oh; Amanda Jiang; Atiq Nurani; Danni Y Zhu; Girija Goyal; Sarah Gilpin; Rachelle Prantil-Baun; Donald E. Ingber

The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.04.13.039917 doi: bioRxiv preprint cells are grown under an air-liquid interface (ALI) on one side of the membrane in the 'airway channel', and this is tissue layer is interfaced with a primary human lung endothelium grown on the opposite side of the same membrane and exposed to continuous fluid flow within the parallel 'vascular channel' (Fig. 1A) . This device supports differentiation of the lung airway basal stem cells into a mucociliary, pseudostratified epithelium with proportions of airway-specific cell types (ciliated cells, mucus-producing goblet cells, club cells, and basal cells) (Fig. S1A) , as well as establishment of continuous ZO1-containing tight junctions and cilia (Fig. 1B) , permeability barrier properties, and levels of mucus production (Fig. S1B ,C) similar to those observed in human airway in vivo 13 , as well as in prior Airway Chip studies that used a membrane with smaller pores (0.4 µm vs. the 7 µm diameter used here) that did not permit immune cell transmigration 6,7 . The underlying human pulmonary microvascular endothelium also formed a continuous planar cell monolayer with cells linked by VE-cadherin containing adherens junctions (Fig. 1B) as it does in vivo. Importantly, the highly differentiated airway epithelium in the Airway Chip expresses higher levels of multiple serine proteases including TMPRSS2, TMPRSS4, TMPRSS11D and TMPRSS11E (DESC1) compared to MDCK cells that are often used to study influenza infection in vitro (Fig. 1C) ; these proteases are essential for the activation and propagation of influenza viruses in vivo. In addition, differentiation of the airway cells at an ALI on-chip is accompanied by large increases in protein (Fig. 1D) and mRNA expression levels of the SARS-CoV-2 receptor, angiotensin converting enzyme-2 (ACE-2) (Fig. 1D,E) , as well as the TMPRSS2 protease (Fig. 1F) , which are also required for infection by SARS-CoV-2 14 . author/funder. All rights reserved. No reuse allowed without permission.