Different Cytokine Response of Primary Colonic Epithelial Cells to Commensal Bacteria

World J Gastroenterol. 2005 Jun 14;11(22):3375-84. doi: 10.3748/wjg.v11.i22.3375.

Abstract

Aim: To determine if primary murine colonic epithelial cells (CEC) respond to commensal bacteria and discriminate between different types of bacteria.

Methods: A novel CEC: bacteria co-culture system was used to compare the ability of the colonic commensal bacteria, Bacteroides ovatus, E. coli (SLF) and Lactobacillus rhamnosus (LGG) to modulate production of different cytokines (n = 15) by primary CEC. Antibody staining and flow cytometry were used to investigate Toll-like receptor (TLR) expression by CEC directly ex vivo and TLR responsiveness was determined by examining the ability of TLR ligands to influence CEC cytokine production.

Results: Primary CEC constitutively expressed functional TLR2 and TLR4. Cultured in complete medium alone, CEC secreted IL-6, MCP-1 and IP-10 the levels of which were significantly increased upon addition of the TLR ligands peptidoglycan (PGN) and lipopolysaccharide (LPS). Exposure to the commensal bacteria induced or up-regulated different patterns of cytokine production and secretion. E. coli induced production of MIP-1alpha/beta and betadefensin3 whereas B. ovatus and L. rhamnosus exclusively induced MCP-1 and MIP-2alpha expression, respectively. TNFalpha, RANTES and MEC were induced or up-regulated in response to some but not all of the bacteria whereas ENA78 and IP-10 were up-regulated in response to all bacteria. Evidence of bacterial interference and suppression of cytokine production was obtained from mixed bacterial: CEC co-cultures. Probiotic LGG suppressed E. coli- and B. ovatus-induced cytokine mRNA accumulation and protein secretion.

Conclusion: These observations demonstrate the ability of primary CEC to respond to and discriminate between different strains of commensal bacteria and identify a mechanism by which probiotic bacteria (LGG) may exert anti-inflammatory effects in vivo.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Bacteria / growth & development
  • Bacteria / immunology*
  • Cells, Cultured
  • Colon / cytology
  • Colon / immunology*
  • Colon / microbiology*
  • Cytokines / immunology*
  • Epithelial Cells / cytology
  • Epithelial Cells / immunology*
  • Epithelial Cells / microbiology*
  • Mice
  • Mice, Inbred C57BL
  • Probiotics
  • Specific Pathogen-Free Organisms

Substances

  • Cytokines