New in vitro models for studying host-pathogen interactions

The study of host-pathogen interactions in the onset and progression of diseases is essential and requires relevant models that mimic the organ ecosystem, including the different cell types constituting the tissue, its 3D architecture (polarisation, multilayers...) and its environment (immune cells, microbiota, air-liquid interface...). For the past fifteen years, we have been developing 3D in vitro models that reproduce a state of differentiation and functionality that is more physiological and closer to the organ than 2D monolayer cultures.

The lungs are constantly exposed to the external environment and to infectious agents, leading to respiratory disorders and severe diseases. These threats represent a significant problem for human and animal health, and economic consequences for society and for livestock. The health crisis related to COVID demonstrates the profound impact that a new virus can have on our societies. Understanding the pathophysiological processes of infection remains one of the main objectives for controlling and treating these respiratory diseases. So in view of the ever-increasing impact of respiratory infections on animal and human health, the scarcity of available in vitro models representing the respiratory epithelia (bronchi, alveolar bronchioles) and the need to limit animal experimentation (3R rules), we have developed new in vitro models (2D, 3D, organoids, ex-vivo sections, 3D bioprint) to study and predict the pathogenicity of respiratory infectious agents affecting humans and animals, and also to test new therapeutic approaches.

♦New in-vitro cellular model that better mimic the lung

Our previous work on the isolation of primary lung cells (Archer et al AJRCMB 2007) already underlined the relevance of 3D culture compared to monolayers  considering expression of markers of differentiation, functionality and viral expression. So based on our experience in the isolation and culture of mammalian lung epithelial cells from different species (human, cattle, sheep), we are developing different models: 

• ◊3D in vitro models: Air-Liquid interface (ALI) and organoids which reproduce the organization of the tissue, with the differentiation of the different cell types, the gain of functionalities (ciliated activity, mucus production) and the response to pathogens, in a more physiological manner. This models are issued from pluripotent stem cell PSC, embryonic stem cells or iPSC (collaboration with B Pain (Stem Cell and Brain Research Institute, Lyon)
• ◊PCLS ex-vivo precision-cuts lung slices, which maintain the complexity of a tissue with its different cell populations. 
• ◊A bioprinted lung model to take lung tissue structuring and regionalisation a step further, using a 3D printing approach, in collaboration with the ICBMS's 3dFAb platform (collab E Petiot 3dFAB - ICBMS).

♦Study and predict the pathogenicity of infectious agents and test new therapeutic approaches using these relevant new in vitro models

Different projects are ongoing deciphering the mechanisms of infectious process regarding different type of human and non-human pathogens (virus, bacteria). :

• ANR EpilunCell : Establishment of epithelial lung cell lines for pathogen investigations .[PI B Pain CSC Lyon-INRAE,  F Archer IVPC;  A Remot/N Winter ISP, D Descamps/S Riffault VIM]. (bRSV, Mycobacterium bovis)
• ANR-Flash-Covid “CovidNanoMed” : Nanoformulations of current therapeutic drug candidates against SARS-CoV-2 for pulmonary delivery”. [PI Bernard Verrier LBTI; F Archer IVPC ; R Legrand IDMIT]
• FINOVI « Myco3DLung Respiratory mycoplasm infection, what could we learn using different respiratory epithelium models in vitro ? » [PI F Tardy ANSES; F Archer] Pathogenic bacteria, Commensal bacteria, Co-infection, Cattle
• ON GOING : 
• Horizon Europe CL6-BIODIV “BCOMING project : Biodiversity Conservation to mitigate the risks of emerging Infectious diseases”  [PI J Cappelle CIRAD, IVPC and 14 other partners] – Characterisation of new strains of the SARS CoV2 virus collected from wild animals in certain regions of Africa and Asia. Sars-Cov-2, emerging viruses
• Horizon Europe Research Infrastructures Programmes :  “ISIDORe (Integrated services for infectious disease outbreak research)[consortium of 17 european entities] : Project Screening of new broad-spectrum antivirals (Collab J Carlson, University of Uppsala). Sars-Cov-2, emerging virus, curative approach
• ANR MucRNAvax project : Evaluation of a mucosal-penetrating LipoParticulate mRNA vaccine vector capable of inducing mucosal immune responses against respiratory infectious diseases. PI B Verrier LBTI, F ARCHER IVCP, S Paul CIRI, Calatrava CIRI). SARS-Cov2, emerging virus, preventive approach
• ANR  Print@Lung : generation of a complex 3D BioImpression lung model mimicking the architecture and cellular composition of the respiratory epithelium, including the stroma and the immune component of the lung (PI F Archer; E Petiot 3dFAB, K Moreau CIRI; S Paul CIRI).
• ShapeMed@Lyon : Transdisciplinary project using the 3D Bioprinted lung model to study infections (viral and bacterial) and the impact of the environment (air pollution) on lung function, including an SHS approach to epistemology and the ethical aspects of using these models (coPIs : F Archer IVPC, E Petiot 3dFAB, K Moreau CIRI; partners : P Doublet CIRI, M Riva IRCELyon, N Lechopier S2HP)