Highly differentiated human airway epithelial cells: a model to study host cell–parasite interactions in pertussis

Abstract

Background Bordetella pertussis colonizes the human respiratory mucosa. Most studies on B. pertussis adherence have relied on cultured mammalian cells that lack key features present in differentiated human airway cells or on animal models that are not natural hosts of B. pertussis. The objectives of this work are to evaluate B. pertussis infection on highly differentiated human airway cells in vitro and to show the role of B. pertussis fimbriae in cell adherence. Methods Primary human airway epithelial (PHAE) cells from human bronchi and a human bronchial epithelial (HBE) cell line were grown in vitro under air-liquid interface conditions. Results PHAE and HBE cells infected with B. pertussis wild type strain revealed bacterial adherence to cell’s apical surface and bacterial induced cytoskeleton changes and cell detachment. Mutations in the major fimbrial subunits Fim2/3 or in the minor fimbrial adhesin subunit FimD affected B. pertussis adherence to predominantly HBE cells. This cell model recapitulates the morphologic features of the human airway infected by B. pertussis and confirms the role of fimbriae in B. pertussis adherence. Furthemore, HBE cells show that fimbrial subunits, and specifically FimD adhesin, are critical in B. pertussis adherence to airway cells. Conclusions The relevance of this model to study host-parasite interaction in pertussis lies in the striking physiologic and morphologic similarity between the PHAE and HBE cells and the human airway ciliated and goblet cells in vivo. These cells can proliferate in vitro, differentiate, and express the same genetic profile as human respiratory cells in vivo.

Histopathology of Bordetella pertussis in the Baboon Model

“…The lack of significant pathology in the trachea is striking. In numerous studies utilizing polarized tracheal or bronchial tissue culture or explanted nasal turbinate, adenoid, or tracheal organ tissue culture, the ciliated epithelial tissues demonstrated ciliostasis, a loss of cilia, cell extrusion, and sloughing of cells when infected with B. pertussis (17)(18)(19). Similar damage was reported in a study examining nasal epithelial biopsy samples taken from children with pertussis (20).…”

Bordetella pertussis Adenylate Cyclase Toxin Disrupts Functional Integrity of Bronchial Epithelial Layers

“…Mammalian epithelial cells grown as submerged monolayers may lack important phenotypic and physiological features of the polarized differentiated human airway epithelial tissue. Indeed, highly differentiated primary human airway epithelial cell layers and cultured HBE-2 bronchial epithelial cells were recently used for infection with B. pertussis to study the role of fimbriae in bacterial adherence to ciliated cells (46). Here we used VA10 epithelial cells that were polarized and differentiated at the air-liquid interface (ALI) and that form pseudostratified epithelial layers with apicobasal polarity, functional tight junctions, and TEER, the hallmarks of epithelial barrier function (47,48).…”

Invited review: human air-liquid-interface organotypic airway tissue models derived from primary tracheobronchial epithelial cells—overview and perspectives

“…However, the molecular mechanism underlying its adherence and colonization has not been thoroughly investigated due to the lack of suitable in vitro models. Guevara and colleagues developed a quantitative adherence assay in ALI airway cultures and identified multiple mutations in the fimbrial adhesin subunits that may contribute to B. pertussis adherence, confirming the essential role of FimD adhesion in this process (Guevara et al 2016).…”