Functional analysis of Lactobacillus rhamnosus GG pili in relation to adhesion and immunomodulatory interactions with intestinal epithelial cells

Sarah Lebeer*, Ingmar Claes, Hanne L. P. Tytgat, Tine L. A. Verhoeven, Eyra Marien, Ingemar von Ossowski, Justus Reunanen, Airi Palva, Willem M. de Vos, Sigrid C. J. De Keersmaecker, Jos Vanderleyden

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Lactobacillus rhamnosus GG, a probiotic with good survival capacity in the human gut, has well-documented adhesion properties and health effects. Recently, spaCBA-encoded pili that bind to human intestinal mucus were identified on its cell surface. Here, we report on the phenotypic analysis of a spaCBA pilus knockout mutant in comparison with the wild type and other adhesin mutants. The SpaCBA pilus of L. rhamnosus GG showed to be key for efficient adherence to the Caco-2 intestinal epithelial cell (IEC) line and biofilm formation. Moreover, the spaCBA mutant induces an elevated level of interleukin-8 (IL-8) mRNA in Caco-2 cells compared to the wild type, possibly involving an interaction of lipoteichoic acid with Toll-like receptor 2. In contrast, an L. rhamnosus GG mutant without exopolysaccharides but with an increased exposure of pili leads to the reduced expression of IL-8. Using Transwells to partition bacteria from Caco-2 cells, IL-8 induction is blocked completely regardless of whether wild-type or mutant L. rhamnosus GG cells are used. Taken together, our data suggest that L. rhamnosus GG SpaCBA pili, while promoting strong adhesive interactions with IECs, have a functional role in balancing IL-8 mRNA expression induced by surface molecules such as lipoteichoic acid.

Original languageEnglish
Pages (from-to)185-193
Number of pages9
JournalApplied and Environmental Microbiology
Volume78
Issue number1
DOIs
Publication statusPublished - Jan 2012
MoE publication typeA1 Journal article-refereed

Keywords

  • GRAM-POSITIVE BACTERIA
  • SALMONELLA-TYPHIMURIUM
  • LIPOTEICHOIC ACID
  • REVEALS
  • EXPRESSION
  • MOLECULES
  • VIRULENCE
  • IMPACT

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