CHARACTERIZATION OF SYNTHETIC HUMAN GRANULOCYTE CHEMOTACTIC PROTEIN-2- USAGE OF CHEMOKINE RECEPTORS CXCR1 AND CXCR2 AND IN-VIVO INFLAMMATORY PROPERTIES
A. Wuyts et al., CHARACTERIZATION OF SYNTHETIC HUMAN GRANULOCYTE CHEMOTACTIC PROTEIN-2- USAGE OF CHEMOKINE RECEPTORS CXCR1 AND CXCR2 AND IN-VIVO INFLAMMATORY PROPERTIES, Biochemistry, 36(9), 1997, pp. 2716-2723
Human granulocyte chemotactic protein 2 (GCP-2) has originally been is
olated from cytokine-stimulated osteosarcoma cells as a chemokine copr
oduced in minute amounts together with interleukin 8. Human GCP-2 (75
residues) was synthesized on a 0.25-mmol scale using Fmoc chemistry. A
fter disulfide bridge formation and purification, monomeric GCP-2 was
recovered as a 6-kDa protein; the pure synthetic protein showed a mole
cular mass of 8076 Da as determined by matrix-assisted laser desorptio
n/ionization mass spectrometry (MALDI-MS). The exact amino acid sequen
ce of synthetic GCP-2 was confirmed by Edman degradation. Synthetic GC
P-2 was an equally active (minimal effective concentration of 1-3 nM)
chemoattractant for neutrophilic granulocytes as was natural 75-residu
e GCP-2. At concentrations up to 30 nM, synthetic GCP-2 did not stimul
ate eosinophil, monocyte, or lymphocyte chemotaxis. GCP-2 induced a do
se-dependent increase in [Ca2+](i) in neutrophils, 1 nM being the mini
mal effective concentration. The GCP-2-induced [Ca2+](i) increase was
completely prevented by pertussis toxin. Prestimulation of neutrophils
with equimolar concentrations of purified natural IL-8, GRO alpha, GR
O gamma and ENA-78 abolished the [Ca2+](i) increase in response to 1 n
M GCP-2. Alternatively, the [Ca2+](i) rise induced by these CXC chemok
ines was inhibited by pretreatment of neutrophils with GCP-2. GCP-2 st
imulated [Ca2+](i) increases in CXCR1- and CXCR2-transfected cells, de
monstrating that GCP-2 binds to both IL-8 receptors. Intradermal injec
tion of synthetic GCP-2 resulted in a dose-dependent neutrophil accumu
lation and plasma extravasation in rabbit skin. To provoke this skin r
eaction, GCP-2. (10 pmol/site) was nearly as effective as IL-8, indica
ting that it is an important complementary mediator of the inflammator
y response.