Glycolipid-Dependent, Protease Sensitive Internalization of Pseudomonas aeruginosa Into Cultured Human Respiratory Epithelial Cells

Clifford Lingwood,William G Carter,Aufaugh Emam

doi:10.2174/1874285801004010106

Clifford Lingwood, William G Carter + Show 1 more

Open Access

https://doi.org/10.2174/1874285801004010106

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Journal: The open microbiology journal	Publication Date: Dec 13, 2010
Citations: 71	License type: cc-by

Affiliation: Hospital for Sick Children

Abstract

Internalization of PAK strain Pseudomonas aeruginosa into human respiratory epithelial cell lines and HeLa cervical cancer cells in vitro was readily demonstrable via a gentamycin protection assay. Depletion of target cell glycosphingolipids (GSLs) using a glucosyl ceramide synthase inhibitor, P4, completely prevented P. aeruginosa internalization. In contrast, P4 treatment had no effect on the internalization of Salmonella typhimurium into HeLa cells. Internalized P. aeruginosa were within membrane vacuoles, often containing microvesicles, between the bacterium and the limiting membrane. P. aeruginosa internalization was markedly enhanced by target cell pretreatment with the exogenous GSL, deacetyl gangliotetraosyl ceramide (Gg4). Gg4 binds the lipid raft marker, GM1 ganglioside. Target cell pretreatment with TLCK, but not other (serine) protease inhibitors, prevented both P. aeruginosa host cell binding and internalization. NFkB inhibition also prevented internalization. A GSL-containing lipid-raft model of P. aeruginosa host cell binding/internalization is proposed

Highlights

Pseudomonas aeruginosa is an opportunistic pathogen primarily associated with the lung pathology and morbidity of cystic fibrosis patients [1]
P. aeruginosa internalization into IB3-1 and S9 cells could be readily detected by protection from gentamycin
We have shown that GSL depletion of target cells has no effect on initial P. aeruginosa adhesion [18], depletion of neutral and

Summary

Introduction

Pseudomonas aeruginosa is an opportunistic pathogen primarily associated with the lung pathology and morbidity of cystic fibrosis patients [1]. P. aeruginosa expresses a broad spectrum of pathological virulence factors responsible for disease [6]. The organism is largely an extracellular pathogen, internalization of P. aeruginosa into target cells has been reported [7, 8]. This internalization process has been proposed to be, in part, responsible for the normal elimination of the organism by induction of host cell apoptosis and macrophage clearance, a process proposed deficient in cystic fibrosis cells [9]

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