Synthetic hexa- and heptapeptides that inhibit IL-8 from binding to and activating human blood neutrophils.
IL-8 is a member of the chemokine alpha subfamily that activates and is chemotactic for neutrophils. In these studies, we have synthesized and characterized a hexapeptide inhibitor of IL-8. This peptide, with an acetylated amino terminus and an amidated carboxyl terminus (Ac-RRWWCR-NH2), inhibited the specific binding of 125I-IL-8 to neutrophils. The inhibition was biphasic and apparent Ki was estimated to be approximately 2.7 microM and 13 microM for two different IL-8 binding sites. The peptide inhibited neutrophil chemotaxis, beta-glucuronidase release from neutrophils, and rabbit skin edema induced by IL-8 with an EC50 of 90 microM, 0.8 microM, respectively. Ac-RRWWCR-NH2 also suppressed the binding of macrophage inflammatory protein (MIP) 2 beta to neutrophils. However, it did not inhibit the binding of MIP-1 alpha, C5a, or leukotriene B4 to neutrophils, chemotaxis induced by FMLP, or beta-glucuronidase release induced by FMLP, C5a, or leukotriene B4. Additional peptides were analyzed to identify a better inhibitor. Inhibition of binding by Ac-rrwwcrc-NH2 synthesized with all D-amino acids was almost four times more potent than Ac-RRWWCR-NH2. Small peptide homologues of the amino-terminal end of IL-8 failed to inhibit IL-8 binding to neutrophils. These studies have identified several peptides that significantly inhibit IL-8 function. Because IL-8 seems to be an important inflammatory mediator of several human illnesses, these peptides may have pharmacologic potential.
Hayashi
S
S
Department of Biochemistry, University of Texas Health Center, Tyler 75710.
Kurdowska
A
A
Miller
E J
EJ
Albright
M E
ME
Girten
B E
BE
Cohen
A B
AB
D000595:Amino Acid Sequence; D002460:Cell Line; D002634:Chemotaxis, Leukocyte; D004487:Edema / Q000276:immunology; D006801:Humans; D016209:Interleukin-8 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D008969:Molecular Sequence Data; D018375:Neutrophil Activation / Q000187:drug effects / Q000276:immunology; D009504:Neutrophils / Q000187:drug effects / Q000276:immunology*; D009842:Oligopeptides / Q000138:chemical synthesis / Q000494:pharmacology*; D018123:Receptors, Interleukin / Q000037:antagonists & inhibitors; D023062:Receptors, Interleukin-8A; D012871:Skin Diseases / Q000276:immunology
D016209:Interleukin-8; D009842:Oligopeptides; D018123:Receptors, Interleukin; D023062:Receptors, Interleukin-8A