Piliation of Lactobacillus rhamnosus GG promotes adhesion, phagocytosis, and cytokine modulation in macrophages

Cynthia E. Vargas Garcia, Mariya Petrova, Ingmar J. J. Claes, Ilke De Boeck, Tine L. A. Verhoeven, Ellen Dilissen, Ingemar von Ossowski, Airi Palva, Dominique M. Bullens, Jos Vanderleyden, Sarah Lebeer*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Recently, spaCBA-encoded pili on the cell surface of Lactobacillus rhamnosus GG were identified to be key molecules for binding to human intestinal mucus and Caco-2 intestinal epithelial cells. Here, we investigated the role of the SpaCBA pilus of L. rhamnosus GG in the interaction with macrophages in vitro by comparing the wild type with surface mutants. Our results show that SpaCBA pili play a significant role in the capacity for adhesion to macrophages and also promote bacterial uptake by these phagocytic cells. Interestingly, our data suggest that SpaCBA pili also mediate anti-inflammatory effects by induction of interleukin-10 (IL-10) mRNA and reduction of interleukin-6 (IL-6) mRNA in a murine RAW 264.7 macrophage cell line. These pili appear to mediate these effects indirectly by promoting close contact with the macrophages, facilitating the exertion of anti-inflammatory effects by other surface molecules via yet unknown mechanisms. Blockage of complement receptor 3 (CR3), previously identified to be a receptor for streptococcal pili, significantly decreased the uptake of pilus-expressing strains in RAW 264.7 cells, while the expression of IL-10 and IL-6 mRNA by these macrophages was not affected by this blocking. On the other hand, blockage of Toll-like receptor 2 (TLR2) significantly reduced the expression of IL-6 mRNA irrespective of the presence of pili.

Original languageEnglish
Pages (from-to)2050-2062
Number of pages13
JournalApplied and Environmental Microbiology
Volume81
Issue number6
DOIs
Publication statusPublished - Mar 2015
MoE publication typeA1 Journal article-refereed

Keywords

  • GREEN FLUORESCENT PROTEIN
  • DENDRITIC CELL
  • FUNCTIONAL-ANALYSIS
  • LACTOCOCCUS-LACTIS
  • LIPOTEICHOIC ACID
  • GENE-EXPRESSION
  • ATOPIC DISEASE
  • PREVENTION
  • CHILDREN
  • PILI

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