Characterization of two novel LPS-binding sites in leukocyte integrin βA domain

Kwong Fai Wong, John M. Luk, R. Holland Cheng, Lloyd B. Klickstein, Sheung Tat Fan

Research output: Contribution to journalArticle

30 Scopus citations

Abstract

Lipopolysaccharide (LPS), a bacterial endotoxin, triggers deleterious systemic inflammatory responses when released into blood circulation, causing organ dysfunction and death. In response to LPS stimulation, CD14 and toll-like receptor (TLR)-4 elicit inflammatory signaling cascades. Although leukocyte integrins (CD11b/CD18 and CD11c/CD18) were reported to bind LPS and induce NF-κB translocation, the evidence on such epitope location remains elusive. The present study aims to delineate the LPS-binding sites on the integrin CD18 antigen and to design peptide(s) as potential prophylactic and/or therapeutic agents to modulate LPS effects in activated Jurkat cells. Epitope mapping analysis using a series of CD18 truncated variants revealed two putative LPS-binding sites within the βA region (216-248 and 266-318 a.a.), which were further confirmed by point mutation studies. Inhibition assay demonstrated that the CD18-βA266-318 peptide could block LPS binding in a dosedependent manner. Our data also indicated that treatment with the CD18-peptide modulated TNF-α mRNA transcription via the NF-κB signaling pathway in LPS-activated Jurkat cells. In conclusion, we have identified two novel LPS-binding sites located at the CD18 βA domain of leukocyte integrin, and the integrin peptide βA266-318 is shown to inhibit LPS binding and subsequent inflammatory events, having therapeutic implications to cure Gram-negative endotoxemia.

Original languageEnglish (US)
Pages (from-to)3231-3239
Number of pages9
JournalFASEB Journal
Volume21
Issue number12
DOIs
StatePublished - Oct 2007

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Keywords

  • Endotoxin-neutralizing peptide
  • Lipopolysaccharide
  • NF-κB
  • Prophylaxis
  • Sepsis
  • TNF-α

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry
  • Cell Biology
  • Medicine(all)

Cite this

Wong, K. F., Luk, J. M., Cheng, R. H., Klickstein, L. B., & Fan, S. T. (2007). Characterization of two novel LPS-binding sites in leukocyte integrin βA domain. FASEB Journal, 21(12), 3231-3239. https://doi.org/10.1096/fj.06-7579com