Extracellular vesicles modulate host-microbe responses by altering TLR2 activity and phagocytosis.

Oral delivery of Gram positive bacteria, often derived from the genera Lactobacillus or Bifidobacterium, can modulate immune function. Although the exact mechanisms remain unclear, immunomodulatory effects may be elicited through the direct interaction of these bacteria with the intestinal epitheliu...

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Main Authors: Jeroen van Bergenhenegouwen, Aletta D Kraneveld, Lieke Rutten, Nienke Kettelarij, Johan Garssen, Arjan P Vos
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2014-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC3930685?pdf=render
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spelling doaj-abdc7fb6741b4fe582c2fe11b74118f02020-11-25T01:34:36ZengPublic Library of Science (PLoS)PLoS ONE1932-62032014-01-0192e8912110.1371/journal.pone.0089121Extracellular vesicles modulate host-microbe responses by altering TLR2 activity and phagocytosis.Jeroen van BergenhenegouwenAletta D KraneveldLieke RuttenNienke KettelarijJohan GarssenArjan P VosOral delivery of Gram positive bacteria, often derived from the genera Lactobacillus or Bifidobacterium, can modulate immune function. Although the exact mechanisms remain unclear, immunomodulatory effects may be elicited through the direct interaction of these bacteria with the intestinal epithelium or resident dendritic cell (DC) populations. We analyzed the immune activation properties of Lactobacilli and Bifidobacterium species and made the surprising observation that cellular responses in vitro were differentially influenced by the presence of serum, specifically the extracellular vesicle (EV) fraction. In contrast to the tested Lactobacilli species, tested Bifidobacterium species induce TLR2/6 activity which is inhibited by the presence of EVs. Using specific TLR ligands, EVs were found to enhance cellular TLR2/1 and TLR4 responses while TLR2/6 responses were suppressed. No effect could be observed on cellular TLR5 responses. We determined that EVs play a role in bacterial aggregation, suggesting that EVs interact with bacterial surfaces. EVs were found to slightly enhance DC phagocytosis of Bifidobacterium breve whereas phagocytosis of Lactobacillus rhamnosus was virtually absent upon serum EV depletion. DC uptake of a non-microbial substance (dextran) was not affected by the different serum fractions suggesting that EVs do not interfere with DC phagocytic capacity but rather modify the DC-microbe interaction. Depending on the microbe, combined effects of EVs on TLR activity and phagocytosis result in a differential proinflammatory DC cytokine release. Overall, these data suggest that EVs play a yet unrecognized role in host-microbe responses, not by interfering in recipient cellular responses but via attachment to, or scavenging of, microbe-associated molecular patterns. EVs can be found in any tissue or bodily fluid, therefore insights into EV-microbe interactions are important in understanding the mechanism of action of potential probiotics and gut immune homeostasis.http://europepmc.org/articles/PMC3930685?pdf=render
collection DOAJ
language English
format Article
sources DOAJ
author Jeroen van Bergenhenegouwen
Aletta D Kraneveld
Lieke Rutten
Nienke Kettelarij
Johan Garssen
Arjan P Vos
spellingShingle Jeroen van Bergenhenegouwen
Aletta D Kraneveld
Lieke Rutten
Nienke Kettelarij
Johan Garssen
Arjan P Vos
Extracellular vesicles modulate host-microbe responses by altering TLR2 activity and phagocytosis.
PLoS ONE
author_facet Jeroen van Bergenhenegouwen
Aletta D Kraneveld
Lieke Rutten
Nienke Kettelarij
Johan Garssen
Arjan P Vos
author_sort Jeroen van Bergenhenegouwen
title Extracellular vesicles modulate host-microbe responses by altering TLR2 activity and phagocytosis.
title_short Extracellular vesicles modulate host-microbe responses by altering TLR2 activity and phagocytosis.
title_full Extracellular vesicles modulate host-microbe responses by altering TLR2 activity and phagocytosis.
title_fullStr Extracellular vesicles modulate host-microbe responses by altering TLR2 activity and phagocytosis.
title_full_unstemmed Extracellular vesicles modulate host-microbe responses by altering TLR2 activity and phagocytosis.
title_sort extracellular vesicles modulate host-microbe responses by altering tlr2 activity and phagocytosis.
publisher Public Library of Science (PLoS)
series PLoS ONE
issn 1932-6203
publishDate 2014-01-01
description Oral delivery of Gram positive bacteria, often derived from the genera Lactobacillus or Bifidobacterium, can modulate immune function. Although the exact mechanisms remain unclear, immunomodulatory effects may be elicited through the direct interaction of these bacteria with the intestinal epithelium or resident dendritic cell (DC) populations. We analyzed the immune activation properties of Lactobacilli and Bifidobacterium species and made the surprising observation that cellular responses in vitro were differentially influenced by the presence of serum, specifically the extracellular vesicle (EV) fraction. In contrast to the tested Lactobacilli species, tested Bifidobacterium species induce TLR2/6 activity which is inhibited by the presence of EVs. Using specific TLR ligands, EVs were found to enhance cellular TLR2/1 and TLR4 responses while TLR2/6 responses were suppressed. No effect could be observed on cellular TLR5 responses. We determined that EVs play a role in bacterial aggregation, suggesting that EVs interact with bacterial surfaces. EVs were found to slightly enhance DC phagocytosis of Bifidobacterium breve whereas phagocytosis of Lactobacillus rhamnosus was virtually absent upon serum EV depletion. DC uptake of a non-microbial substance (dextran) was not affected by the different serum fractions suggesting that EVs do not interfere with DC phagocytic capacity but rather modify the DC-microbe interaction. Depending on the microbe, combined effects of EVs on TLR activity and phagocytosis result in a differential proinflammatory DC cytokine release. Overall, these data suggest that EVs play a yet unrecognized role in host-microbe responses, not by interfering in recipient cellular responses but via attachment to, or scavenging of, microbe-associated molecular patterns. EVs can be found in any tissue or bodily fluid, therefore insights into EV-microbe interactions are important in understanding the mechanism of action of potential probiotics and gut immune homeostasis.
url http://europepmc.org/articles/PMC3930685?pdf=render
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