Neuraminidase Enhances Pseudomonas Aeruginosa Secretome Disruption of the Rat Pulmonary Microvascular Endothelial Cell Monolayer

Abstract

Neuraminidase (NA), an enzyme that removes sialic acids and is produced by many pathogenic organisms, has previously been shown to cause endothelial barrier disruption. P. aeruginosa strains secrete a variety of proteins, including NA, into the extracellular environment, the collection of which may be termed the secretome. Many of these proteins are virulence factors and expression can vary across strains, as well as over the course of growth and in response to environmental factors. For example, strain PAO1 expresses LasB, an elastase which has been previously implicated in disruption of endothelial monolayers by cleaving VE‐cadherin, which is sialylated, but strain Pa103 does not. This study investigates the role of NA in P. aeruginosa secretome disruption of the pulmonary microvascular endothelial cell (PMVEC) monolayer. PMVEC monolayers were treated with secretome from various P. aeruginosa strains including the wildtype PAO1, a NA deleted strain, PAO1Δ2794, and the wildtype strain Pa103. Secretomes from the different strains caused gap formation in the PMVEC monolayer at differing times. Large gaps were observed at 18 hours after treatment with PAO1 secretome, while similar damage from the PAO1Δ2794 secretomes was not observed until 26 hours after treatment. Only minor damage was observed upon treatment with Pa103 secretome at any time point. The delay in damage observed between the wild‐type secretome treatment and the NA‐deleted secretome lead to the conclusion that NA enhances disruption of the PMVEC barrier by P. aeruginosa PAO1 secretome. Supported by R01HL107778.