Speaker
Description
Background and objectives
Postinfluenza models of Staphylococcus aureus pneumonia demonstrate the severe outcome of a coinfection associated with substantial morbidity and mortality for patients. To date, investigations concerning microbial infections of the lung are usually carried out in animal models. However, lung anatomy and physiology as well as composition of the immune system differ significantly between rodents and men.
To investigate cell processes between epithelial, endothelial and immune cells after influenza virus/ S. aureus coinfection, we aimed to establish a human alveolus-model recreating a reactive tissue-tissue interface between the vascular endothelium and the airway-facing epithelium.
Methods/Results
For this reason, MOTiF biochips were seeded with human endothelial cells on the vascular site and with epithelial cells and macrophages on the airway site (Figure 1). This organoid was cultured for up to 14 days with a robust and stable air-liquid interphase under dynamic flow conditions. Barrier integrity was proven by transepithelial electrical resistance (TEER) measurements and permeability assays. Expression and localization of cell-type specific markers and functional proteins was proven by immunofluorescence. Viral and bacterial infection occurs trough airway site with further designation of acute phase of invasion and early immune response thereafter up to 8 hours, depending of multiplicity of infection (MOI).
Dynamic conditions for maintaining ALI allow a stable barrier with high transepithelial resistance and an intact vascularity. We will provide evidence for an increase of barrier integrity after introduction of macrophages proven by TEER measurement and permeability tests. Our data indicate an stable surfactant production of alveolar epithelial cells type II. Subsequent infection has been successfully established and pathogenicity factors can be investigated.
Conclusions
We established a functional, biochip-based human in vitro alveolus model that is suitable for investigation of complex co-infections. Separated airway and vascular chambers allow an infection with a pathogen from the airway site. Thereby inducing an immune response, it is possible to observe migration of immune cells from the vascular site into the infected sites to study species-specific mechanism of pathogens.
Figure 1: Schematic composition of the alveolus model. The cavity in the chip is divided by a porous membrane into an upper and a lower chamber. The membrane serves as a scaffold for cells. Vascular endothelial cells are cultured beneath the membrane in the lower chamber. Alveolar epithelial cells and macrophages are co-cultured on top of the membrane. Nutrient and oxygen supply is achieved by perfusion of the vascular chamber. After reaching confluency cells are co-cultured at an air-liquid-interphase for up to 14 days.
| Choose primary session | Virus host cell interaction |
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| Choose secondary Session | Virus host cell interaction |
