Accelerating SARS-CoV2 antiviral drug discovery using next generation 3D bioprinted scaffolds

Strategic priority area:Industrial collaborative research. Keywords:Drug discovery, SARS-CoV2, respiratory tissue

The pandemic spread of SARS-CoV2, the principle etiological agent of COVID-19, has identified an urgent need for alternative methodologies for the rapid screening & identification of antiviral compounds that limit the pathogenesis & transmission of zoonotic pathogens;specifically in high-risk category groups susceptible to auto-immune and inflammatory disease.This observation is supported by the inherent delays in vaccine production & global immunization required to protect an immuno-naïve population during a pandemic outbreak.Standard screening approaches for the identification of small molecule inhibitors (SMIs) have relied heavily on two-dimensional (2D) cell-based infection assays.While amenable to high-throughput screening, these 2D systems poorly reflect the three-dimensional physiology,mixed cell-type population,or pharmacokinetic properties of the respiratory airway.Consequently, extensive & time-consuming secondary validation assays are required prior to SMI pre-clinical animal testing.Utilizing primary bronchial cells obtained from healthy donors,which contain a mixture of epithelial, fibroblast & goblet cells,we have shown the differentiation of ciliated 3D respiratory epithelium to readily support SARS-CoV2 infection.While amenable to low-throughput inhibitor studies & secondary assay testing,the use of Transwell technology for the differentiation of respiratory cells is time consuming (minimum 4 weeks),labour intensive, & incompatible with automated imaging techniques required for high-throughput SMI screening.Thus, in the case of emerging pathogens that show tropism for differentiated respiratory epithelia new methodologies are required to facilitate the rapid identification of antiviral compounds directly within respiratory tissue.Recent advances in 3D bioprinting have revolutionized the development & mass production of 'next generation' biomolecular scaffolds that can support the differentiation of multiple cell-types.This project will build on an existing collaboration with Cellbricks, a SME company (https://cellbricks.com) which utilizes a proprietary stereolithography-based bioprinting platform to produce biomolecular scaffolds that support the internal adhesion of cells onto a 3D biopolymer matrix.The use of such scaffolds has many distinct advantages over that of existing Transwell or organoid model systems: (1) Constrained internal dimensions for reproducible cell seeding and downstream infection kinetic assays; (2) Internal 3D micro-bays to promote cell adhesion and differentiation; (3) Optical clarity suitable to high-resolution and high-throughput quantitative imaging; (4) stratification of drugs directly in respiratory tissue established from non-infected high-risk donor groups.The objective of this project is to establish the use of these prefabricated 3D scaffolds in the high-throughput screening,identification & stratification of SMI compounds to SARS-CoV2 directly within respiratory tissue;thereby circumventing the need for time consuming secondary validation assays prior to animal testing in vivo.

Trainee and project outcomes:This project will provide extensive training in infectious disease research (MRC-UoG CVR) & biomolecular engineering (Cellbricks).This project will develop key translational research skills applicable to both academia & industry,with clearly defined research aims & expertise pertinent to global health,drug discovery, and precision medicine.Outputs from this project will aid the development of novel methodologies relevant to the identification of antiviral compounds to emerging zoonotic pathogens that will support the career progression of its trainee in academia or industry. Outputs from this project will facilitate the identification and stratification of antiviral inhibitors in the treatment of SARS-CoV2 infected COVID-19 patients from high risk groups.