Lactobacillus delbrueckii TUA4408L and its extracellular polysaccharides attenuate enterotoxigenic Escherichia coli-induced inflammatory response in porcine intestinal epitheliocytes via Toll-like receptor-2 and 4

Mol Nutr Food Res. 2014 Oct;58(10):2080-93. doi: 10.1002/mnfr.201400218. Epub 2014 Aug 5.


Scope: Immunobiotics are known to modulate intestinal immune responses by regulating Toll-like receptor (TLR) signaling pathways, which are responsible for the induction of cytokines and chemokines in response to microbial-associated molecular patterns. However, little is known about the immunomodulatory activity of compounds or molecules from immunobiotics.

Methods and results: We evaluated whether Lactobacillus delbrueckii subsp. delbrueckii TUA4408L (Ld) or its extracellular polysaccharide (EPS): acidic EPS (APS) and neutral EPS (NPS), modulated the response of porcine intestinal epitheliocyte (PIE) cells against Enterotoxigenic Escherichia coli (ETEC) 987P. The roles of TLR2, TLR4, and TLR negative regulators in the immunoregulatory effects were also studied. ETEC-induced inflammatory cytokines were downregulated when PIE cells were prestimulated with both Ld or EPSs. Ld, APS, and NPS inhibited ETEC mediated mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) activation by upregulating TLR negative regulators. The capability of Ld to suppress inflammatory cytokines was diminished when PIE cells were blocked with anti-TLR2 antibody, while APS failed to suppress inflammatory cytokines when cells were treated with anti-TLR4 antibody. Induction of Ca²⁺ fluxes in TLR knockdown cells confirmed that TLR2 plays a principal role in the immunomodulatory action of Ld, while the activity of APS is mediated by TLR4. In addition, NPS activity depends on both TLR4 and TLR2.

Conclusion: Ld and its EPS have the potential to be used for the development of anti-inflammatory functional foods to prevent intestinal diseases in both humans and animals.

Keywords: Anti-inflammatory activity; Extracellular polysaccharides; L. delbrueckii; PIE cells; TLR negative regulators; TLR2; TLR4.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium Signaling / drug effects
  • Cell Line
  • Cytokines / agonists
  • Cytokines / metabolism
  • Enterocytes / immunology*
  • Enterocytes / metabolism
  • Enterocytes / microbiology
  • Enterotoxigenic Escherichia coli / immunology*
  • Immunity, Mucosal* / drug effects
  • Lactobacillus delbrueckii / immunology*
  • Lactobacillus delbrueckii / metabolism
  • MAP Kinase Signaling System / drug effects
  • Polysaccharides, Bacterial / metabolism
  • Polysaccharides, Bacterial / pharmacology*
  • Probiotics / metabolism
  • RNA Interference
  • RNA, Small Interfering
  • Surface Properties
  • Sus scrofa
  • Toll-Like Receptor 2 / agonists*
  • Toll-Like Receptor 2 / antagonists & inhibitors
  • Toll-Like Receptor 2 / genetics
  • Toll-Like Receptor 2 / metabolism
  • Toll-Like Receptor 4 / agonists*
  • Toll-Like Receptor 4 / antagonists & inhibitors
  • Toll-Like Receptor 4 / genetics
  • Toll-Like Receptor 4 / metabolism


  • Cytokines
  • Polysaccharides, Bacterial
  • RNA, Small Interfering
  • Toll-Like Receptor 2
  • Toll-Like Receptor 4