Pietro Vernazza, Switzerland

Cantonal Hospital St. Gallen Infectious Diseases and Hospital Epidemiology

Author Of 1 Presentation

IMPACT OF THE COM QUORUM SENSING SYSTEM ON THE TIGHT JUNCTION BELT DURING PNEUMOCOCCAL INVASION OF DIFFERENTIATED HUMAN BRONCHIAL EPITHELIAL CELLS (ID 681)

Abstract

Background

The tight junction (TJ) belt contributes to epithelial integrity during pneumococcal invasive disease. We investigated the effect of S. pneumoniae (Spn) invasion and translocation on TJ proteins and the role of Com, a quorum sensing system essential for the evolution of Spn.

Methods

A pseudostratified human airway epithelial tissue (HAE) model was developed with bronchial cells from donors. HAE cells were infected with TIGR4, or TIGR4ΔcomC, at different densities and incubated for up to 30 h. Pneumococci colonizing and those translocated to the basolateral side were quantified. Transepithelial electrical resistance (TEER), confocal/electron microscopy, ELISA for TJ proteins, and transcriptional analysis of genes encoding for ZO-1, claudin-4, and claudin-7, were performed.

Results

Infection with TIGR4 induced a dose-dependent decrease of TEER that correlated with invasion/translocation. Unexpectedly, a further decrease of TEER, with increased invasion, was induced by TIGR4ΔcomC compared to wt. Supernatant levels of ZO-1 and claudin-7 were increased when bacteria translocated, and were higher in HAE infected with TIGR4ΔcomC. Transcription of the ZO-1 gene was downregulated during infection with either strain, and further downregulated during the translocation stage.

Conclusions

S. pneumoniae invades, and translocates through, HAE cells by targeting TJ proteins. Knocking-down Com resulted in greater invasion and enhanced disturbance of the TJ.

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