TNF-α sensitizes HT-29 colonic epithelial cells to intestinal lactobacilli

Vance J. McCracken, Taehoon Chun, Manuel E. Baldeo, Siv Ahrne, Göran Molin, Roderick I. Mackie, H. Rex Gaskins

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37 Citations (Scopus)

Abstract

The ability of the proinflammatory cytokine tumor necrosis factor-α (TNF-α) to influence epithelial interleukin (IL)-8 responses to the intestinal bacterium Lactobacillus plantarum 299v was analyzed in the human HT-29 colonic epithelial cell line. In the absence of TNF-α, IL-8 mRNA expression was not detectable by Northern blot analysis in HT-29 cells alone or in HT-29 cells co-cultured with L. plantarum 299v. However, TNF-α induced IL-8 mRNA expression, and co-culture of TNF-αtreated HT-29 cells with L. plantarum 299v significantly increased IL-8 mRNA expression above levels induced by TNF-α alone in an adhesion-dependent manner. The increase in IL-8 mRNA expression was not observed in TNF-α-treated HT-29/L. plantarum 299v cocultures using heat-killed lactobacilli or when L. plantarum adhesion was prevented using mannoside or a trans-well membrane. Paradoxically, IL-8 secretion was decreased in TNF-αtreated HT-29 cells with L. plantarum 299v relative to cells treated with TNF-α alone. TNF-α-mediated responsiveness to L. plantarum 299v was further investigated by analyzing expression of a coreceptor for bacterial cell wall products CD14. HT-29 cells expressed CD14 mRNA and cell-surface CD14; however, TNF-α did not alter CD14 mRNA or cell-surface expression, and blockade of CD14 with monoclonal antibody MY4 did not alter the IL-8 response to L. plantarum 299v in TNF-α-treated HT-29 cells. These results indicate that although TNF-α sensitizes HT-29 epithelial cells to intestinal lactobacilli, the bacteria exert a protective effect by downregulating IL-8 secretion.

Original languageEnglish
Pages (from-to)665-670
Number of pages6
JournalExperimental Biology and Medicine
Volume227
Issue number8
Publication statusPublished - 2002 Sep 1

Keywords

  • CD14
  • Interleukin-8
  • Intestinal epithelial cell
  • Lactobacillus

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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    McCracken, V. J., Chun, T., Baldeo, M. E., Ahrne, S., Molin, G., Mackie, R. I., & Rex Gaskins, H. (2002). TNF-α sensitizes HT-29 colonic epithelial cells to intestinal lactobacilli. Experimental Biology and Medicine, 227(8), 665-670.