Bioprinted Multi-Cell Type Lung Model for the Study of Viral Inhibitors.

Johanna Berg,Stefan Hippenstiel,Marie Weinhart,Mona Fechler-Bitteti,Jens Kurreck,Zia Weber,Andreas C. Hocke,Laura Elomaa

doi:10.3390/v13081590

Abstract

Influenza A virus (IAV) continuously causes epidemics and claims numerous lives every year. The available treatment options are insufficient and the limited pertinence of animal models for human IAV infections is hampering the development of new therapeutics. Bioprinted tissue models support studying pathogenic mechanisms and pathogen-host interactions in a human micro tissue environment. Here, we describe a human lung model, which consisted of a bioprinted base of primary human lung fibroblasts together with monocytic THP-1 cells, on top of which alveolar epithelial A549 cells were printed. Cells were embedded in a hydrogel consisting of alginate, gelatin and collagen. These constructs were kept in long-term culture for 35 days and their viability, expression of specific cell markers and general rheological parameters were analyzed. When the models were challenged with a combination of the bacterial toxins LPS and ATP, a release of the proinflammatory cytokines IL-1β and IL-8 was observed, confirming that the model can generate an immune response. In virus inhibition assays with the bioprinted lung model, the replication of a seasonal IAV strain was restricted by treatment with an antiviral agent in a dose-dependent manner. The printed lung construct provides an alveolar model to investigate pulmonary pathogenic biology and to support development of new therapeutics not only for IAV, but also for other viruses.

Highlights

The human lung is the primary target organ for many viral and bacterial pathogens [1].Lower respiratory tract infections caused by influenza A virus (IAV) infections are still a major cause of morbidity and mortality worldwide [2,3]
Within the last few years, bioprinting has become interesting for pharmaceutical applications in terms of drug testing and high-throughput screening
With the recent viral outbreaks of SARS-CoV-2, SARS, MERS, Zika and the influenza outbreaks of 2009 (H1N1) and 2013 (H7N9), human 3D lung models in general [50,51], and bioprinting technologies in particular, have gained significantly more traction in research devoted to combating infectious diseases [52]

Summary

Introduction

The human lung is the primary target organ for many viral and bacterial pathogens [1].Lower respiratory tract infections caused by influenza A virus (IAV) infections are still a major cause of morbidity and mortality worldwide [2,3]. In addition to seasonal IAV strains, the emergence of pandemic IAV strains, such as H1N1 in 2009, results in even higher infectivity and pathogenicity [4,5], as they are often accompanied by an uncontrolled, severe response from the immune system [6,7,8]. In addition to IAV, bacteria can enter the deeper regions of the lung and infect alveolar epithelium [12,13]. Bacterial toxins such as lipo-poly-saccharide (LPS) or pneumolysin (PLY) induce the secretion of pro-inflammatory cytokines, including interleukin 1β (IL-1β), tumor necrosis factor α (TNFα) and IL-8, contributing to a severe immune reaction [14,15,16,17]. The resulting increase in migration and activation of macrophages facilitates this excessive inflammatory response [13,16,18]

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