Establishment of ruminant cell lines for replication and study of specific pathogens – EpiLungCell

Lungs are constantly exposed to the external environment, the infectious and toxic agents present in the air. Both viral and bacterial pathogens trigger damage to the lung epithelial cells leading to the alteration of the respiratory efficiency and in some cases to severe illness of the affected person or animal. Understanding the physio-pathological processes of infection remains one of the main goals to control and treat the diseases. Those threats represent major health and economic issues for cattle and among them, bovine tuberculosis and bronchopneumonia are two major pathologies. These bovine diseases have their human counterparts, namely bronchiolitis in infants and human tuberculosis. Being able to predict the pathogenicity of different circulating or emerging strains of virus or bacteria, could help to better apprehend the disease and develop preventive or curative measures. To better understand the determinants of the infectious process, to study the cell-pathogen interactions and to be able to predict the virulence of respiratory pathogens, it is necessary to have relevant and innovative study models. Indeed, very few reliable in vitro models mimic the lower respiratory tract and more precisely the alveolar compartment, the offensive site of these pathogens. In order to specifically study the reactivity of pulmonary epithelial cells to respiratory bacteria and virus and their involvement in the infectious process, we propose to develop alternative in vitro models using the stem cell plasticity to the in vivo experimental approaches. The EpiLungCell main aims are:
i) to develop new in vitro cellular models mimicking the different stages of lung epithelial state of differentiation, from iPS (induced Pluripotent Stem) and eIP (induced Epithelial Progenitor) cells to mature bronchiolar and alveolar epithelial cells.
ii) to challenge these cells with Respiratory Syncytial Virus (RSV), and Mycobacterium bovis (Mb) pathogens and to investigate the functional consequences of the infection on their physiology.
iii) to propose those substrates as tools to evaluate the pathogenicity of new viral or bacterial respiratory strains.
The EpiLungCell project takes place over 3 years and is divided into four work packages (WP). The first WP aims to establish new cellular substrates with original epithelial phenotypes. The physiological response of these substrates to infection by bacteria such as Mb (second WP) or by the RSV virus (third WP) will be studied and compared at the molecular and cellular levels with what is observed in cells directly derived from animal models. Finally, in a fourth and final WP, these new substrates will be developed and used for diagnostic purposes to identify and predict the pathogenicity of new strains identified and isolated directly from the field. The development and the use of these cellular substrates also aim to reduce the use of animal models in the study of these pathogens.
The main results of the proposal will be the production of new cell lines, in particular lung epithelial cells, a better understanding of the mechanisms of infection by these pathogens and the development of new diagnostic tools. The two aspects of basic knowledge with cell response to infection and of applied science with the diagnostic tool will thus be satisfied. Together, it will provide a better understanding of the physiology of the pulmonary epithelium, its characterization, its susceptibility to infectious agents and its alterations during the infectious processes.