(M-482) Rapidly Generated Lung Organoids as a Physiologically Relevant In-Vitro Model for Studying Respiratory Viral Infections and Host-Virus Interactions"
Introduction:: The lung, a primary target for highly lethal respiratory viruses like influenza and coronaviruses, experiences related infections that rank as the fourth leading cause of death globally. Developing a physiologically accurate in-vitro lung viral infection model has been difficult due to several limitations, such as time for model generation, scalability, unrepresentative fetal phenotype, lack of distinct anatomical regions, and inability to replicate complex branching morphogenesis and diverse cellular populations in proximal and distal lung regions. This study aims to address these limitations by creating an in-vitro model for studying emerging viral threats within a rapidly generated and physiologically pertinent context.
Materials and Methods:: Lower respiratory tract organoids containing markers for both proximal and distal lung regions were produced through interactions between human airway epithelial cells (immortalized and primary) and fetal fibroblasts. Cell differentiation into various epithelium subtypes was induced by controlling the microenvironment. The organoids were characterized using immunofluorescence, RNA sequencing, and flow cytometry, Additionally, Tandem Mass Tags (TMT) were employed to identify proteins expressed in the organoids that contribute to tissue development, cell differentiation, and tube formation.
Results, Conclusions, and Discussions:: The organoids generated in this study exhibited goblet, secretory, basal, and alveolar types I and II cell populations, with morphology imitating lung tissue morphogenesis over time and forming macrostructures exceeding 10000 μm in size. The organoid proteome closely resembled adult lung tissue, with upregulated proteins associated with the innate immune system for improved threat response. As a proof of concept, the organoid model was successfully infected with influenza H1N1 and SARS-CoV-2, suggesting its potential applicability for studying other emerging or re-emerging viral infections.
Our findings demonstrate that the developed organoids possess key features of adult lung tissue, which could provide a physiologically relevant in-vitro model for studying respiratory viral infections. The ability to rapidly generate and accurately represent lung tissue morphogenesis and diverse cellular populations addresses current limitations in existing models. The upregulation of proteins linked to the innate immune system in the organoids highlights their potential for studying host-virus interactions and understanding viral pathogenesis. This physiologically relevant model may contribute to a better understanding of viral pathogenesis and the development of novel in-vitro therapies for emerging and re-emerging viral infections.
