Surface glycosaminoglycans mediate adherence between HeLa cells and Lactobacillus salivarius Lv72

Rebeca Martín,Juan E Suárez,Susana Escobedo,Carla Martín,Luis M Quirós

doi:10.1186/1471-2180-13-210

Rebeca Martín, Juan E Suárez + Show 3 more

Open Access

https://doi.org/10.1186/1471-2180-13-210

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Abstract

BackgroundThe adhesion of lactobacilli to the vaginal surface is of paramount importance to develop their probiotic functions. For this reason, the role of HeLa cell surface proteoglycans in the attachment of Lactobacillus salivarius Lv72, a mutualistic strain of vaginal origin, was investigated.ResultsIncubation of cultures with a variety of glycosaminoglycans (chondroitin sulfate A and C, heparin and heparan sulfate) resulted in marked binding interference. However, no single glycosaminoglycan was able to completely abolish cell binding, the sum of all having an additive effect that suggests cooperation between them and recognition of specific adhesins on the bacterial surface. In contrast, chondroitin sulfate B enhanced cell to cell attachment, showing the relevance of the stereochemistry of the uronic acid and the sulfation pattern on binding. Elimination of the HeLa surface glycosaminoglycans with lyases also resulted in severe adherence impairment. Advantage was taken of the Lactobacillus-glycosaminoglycans interaction to identify an adhesin from the bacterial surface. This protein, identify as a soluble binding protein of an ABC transporter system (OppA) by MALDI-TOF/(MS), was overproduced in Escherichia coli, purified and shown to interfere with L. salivarius Lv72 adhesion to HeLa cells.ConclusionsThese data suggest that glycosaminoglycans play a fundamental role in attachment of mutualistic bacteria to the epithelium that lines the cavities where the normal microbiota thrives, OppA being a bacterial adhesin involved in the process.

Highlights

The adhesion of lactobacilli to the vaginal surface is of paramount importance to develop their probiotic functions
Interference of GAGs on HeLa cell-Lactobacillus salivarius Lv72 adhesion To study the role of GAGs on Lv72 adhesion to HeLa cells, addition of commercial preparations of HS, heparin, CS A or CS C to HeLa to cell monolayers was performed immediately before the addition of exponentially growing L. salivarius Lv72 cells
The estimated dissociation constants (KD) were of 2.5 nM for HS, 6.8 nM for CS A, 39.9 nM for CS C and 280.9 nM for heparin, which indicates that the affinity of the bacteria for the different receptors varied markedly, up to two orders of magnitude between HS and heparin

Summary

Introduction

The adhesion of lactobacilli to the vaginal surface is of paramount importance to develop their probiotic functions For this reason, the role of HeLa cell surface proteoglycans in the attachment of Lactobacillus salivarius Lv72, a mutualistic strain of vaginal origin, was investigated. Identification of the proteins secreted by the bacteria and those anchored to its cell wall has provided lists of polypeptides putatively involved in mucous adherence. This approach has identified enzymes related to sugar catabolism, such as glyceraldehyde-3-phosphate dehydrogenase and enolase [9,10,11,12]

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