Responsiveness of intestinal epithelial cell lines to lipopolysaccharide is correlated with Toll-like receptor 4 but not Toll-like receptor 2 or CD14 expression (original) (raw)

Abstract

Background and aims. Luminal bacteria have been implicated in the pathogenesis of inflammatory bowel diseases. Exposure of intestinal epithelial cells (IEC) to bacterial components potentially initiates intestinal inflammation by release of chemokines and recruitment of inflammatory cells. We analyzed receptor expression and signaling pathways involved in activation of human primary IEC and carcinoma-derived cell lines by lipopolysaccharide (LPS).

Materials and methods. HT-29/p, HT-29/MTX, and Caco-2 cells were stimulated by LPS. IL-8 content in supernatants was analyzed by ELISA, and expression of CD14, Toll-like receptor (TLR) 2 and TLR 4 was determined by RT-PCR. Presence of TLR 4 protein was assessed by western blot analysis. LPS response was modulated by sCD14, LPS-binding protein, neutralization of CD14, and inhibitors of early signal activation.

Results. LPS dose-dependently induced secretion of IL-8 in undifferentiated HT-29/p cells while Caco-2 and permanently differentiated HT-29/MTX cells were unresponsive. Differently to HT-29/MTX, both HT-29/p and Caco-2 cells constitutively expressed transcripts for CD14. However, CD14 was not required for LPS-mediated induction of IL-8 in HT-29/p cells since neutralizing anti-CD14 antibodies left IL-8 levels unchanged. Unresponsiveness of Caco-2 and HT-29/MTX cells to LPS persisted in the presence of sCD14 and/or LPS-binding protein. Neither cell line expressed TLR 2 transcripts while only responsive HT-29/p cells expressed TLR 4 mRNA and TLR 4 protein. Butyrate down-regulated TLR 4 expression and significantly diminished LPS-dependent IL-8 secretion. Inhibition of G protein dependent kinase activation reduced IL-8 levels to 50%; the phosphatidyl-inositol-3′-kinase inhibitor LY294002 abrogated the response.

Conclusion. Responsiveness of IEC lines to LPS is positively correlated with TLR 4 expression. Strategies targeting TLR 4 expression or TLR 4 mediated signaling may antagonize IEC activation by LPS.

Access this article

Log in via an institution

Subscribe and save

Buy Now

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

Author information

Authors and Affiliations

  1. Department of Medicine II and Medical Research Center, University of Heidelberg, Medical Faculty of Mannheim, Theodor-Kutzer-Ufer, 68167 Mannheim, Germany, , , , ,
    Ulrich Böcker, Oleksandr Yezerskyy, Peter Feick, Tobias Manigold, Frank Herweck, Siegbert Rossol & Manfred V. Singer
  2. Division of Gastroenterology, Hepatology, and Nutrition, Winthrop University Hospital, Mineola, NY 11051, USA, , , , ,
    Asit Panja
  3. Department of Hematology, University Hospital Frankfurt, 60590 Frankfurt, Germany, , , , ,
    Uwe Kalina

Authors

  1. Ulrich Böcker
    You can also search for this author inPubMed Google Scholar
  2. Oleksandr Yezerskyy
    You can also search for this author inPubMed Google Scholar
  3. Peter Feick
    You can also search for this author inPubMed Google Scholar
  4. Tobias Manigold
    You can also search for this author inPubMed Google Scholar
  5. Asit Panja
    You can also search for this author inPubMed Google Scholar
  6. Uwe Kalina
    You can also search for this author inPubMed Google Scholar
  7. Frank Herweck
    You can also search for this author inPubMed Google Scholar
  8. Siegbert Rossol
    You can also search for this author inPubMed Google Scholar
  9. Manfred V. Singer
    You can also search for this author inPubMed Google Scholar

Additional information

Electronic Publication

Rights and permissions

About this article

Cite this article

Böcker, U., Yezerskyy, O., Feick, P. et al. Responsiveness of intestinal epithelial cell lines to lipopolysaccharide is correlated with Toll-like receptor 4 but not Toll-like receptor 2 or CD14 expression.Int J Colorectal Dis 18, 25–32 (2003). https://doi.org/10.1007/s00384-002-0415-6

Download citation