A peptide derived from the amino terminus of endothelial-monocyte- activating polypeptide II modulates mononuclear and polymorphonuclear leukocyte functions, defines an apparently novel cellular interaction site, and induces an acute inflammatory response

J. Kao, Y. G. Fan, I. Haehnel, J. Brett, S. Greenberg, M. Clauss, M. Kayton, K. Houck, W. Kisiel, R. Seljelid, J. Burnier, D. Stern

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Abstract

Endothelial-monocyte-activating polypeptide II (EMAP II) is a novel mediator isolated from conditioned medium of methylcholanthrene A-induced tumor cells which modulates properties of endothelial cells, mononuclear phagocytes (MPs), and polymorphonuclear leukocytes (PMNs) in vitro and induces an acute inflammatory response in vivo. A synthetic peptide comprising 15 residues from the N-terminal region (residues 6-20) was shown to induce directional migration of MPs and PMNs, with half-maximal effect at ≃200-250 pM, whereas a peptide from the C terminus of EMAP II, as well as other irrelevant peptides, were without effect. Modulation of cellular phenotype by EMAP II-derived peptide was suggested by peptide-induced elevation of cytosolic free calcium concentration in fura-2-loaded MPs and PMNs and by stimulation of peroxidase release in PMNs. Consistent with these in vitro data, EMAP II-derived N-terminal peptide-albumin conjugates injected into the mouse footpad elicited inflammatory cell tissue infiltration, whereas albumin alone or EMAP II-derived C-terminal peptide conjugated to albumin incited little response. Binding of 125I-labeled EMAP II-derived peptide (residues 12-20) to MPs was saturable (K(d) ≃200 pM) and was blocked in a dose-dependent manner by the addition of intact EMAP II and unlabeled EMAP II-derived peptides (residues 6-20 and 12-20), whereas interleukin 1, tumor necrosis factor, formyl-methionyl-leucinylphenylalanine, or irrelevant peptides were without effect. Cross-linking of 125I-EMAP II-derived peptide (residues 12-20) by disuccinimidyl suberate to human MPs demonstrated a band, ≃73 kDa, on reduced sodium dodecyl sulfate-polyacrylamide gel electrophoresis. 125I-EMAP II-derived peptide also demonstrated specific binding to human PMNs and murine RAW cells. These data indicate that the N- terminal region of EMAP II defines a biologically active locus of the molecule which interacts with target cells via a potentially novel cellular receptor.

Original languageEnglish (US)
Pages (from-to)9774-9782
Number of pages9
JournalJournal of Biological Chemistry
Volume269
Issue number13
StatePublished - Jan 1 1994

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ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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