Published online before print May 20, 2004

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(Journal of Leukocyte Biology. 2004;76:477-483.)
© 2004 by Society for Leukocyte Biology

CP-64131, an aminobenzazepine with cytokine-like properties, stimulates human neutrophil functions through the p38-MAPK pathway

Marsha S. Anderson^*,, Cindy Knall^,1, Gail Thurman^*, Don Mann, Nancy Cusack, Gary L. Johnson^,¶,2 and Daniel R. Ambruso^*,,3

^* Bonfils Blood Center, Denver, Colorado;
Program in Molecular Signal Transduction, Division of Basic Sciences, Department of Pediatrics, National Jewish Medical Research Center, Denver, Colorado; Departments of
^¶ Pharmacology and
Pediatrics, University of Colorado Health Sciences Center, Denver; and
Central Research Division, Pfizer, Inc., Groton, Connecticut

³Correspondence: Bonfils Blood Center, 717 Yosemite Street, Denver, CO 80230. E-mail: daniel.ambruso{at}uchsc.edu

CP-64131 (CP), an aminobenzazepine with cytokine-like, physiologic effects similar to granulocyte-colony stimulating factor (G-CSF) and granulocyte macrophage (GM)-CSF, increases the number of neutrophils and stimulates marrow recovery after doxirubicin ablation. CP can also function as a neutrophil agonist, like formyl-Met-leu-Phe (fMLP). In these studies, we show that CP is unique in that it stimulates the p38-mitogen-activated protein kinase (MAPK) pathway but not extracellular signal-regulated kinase (ERK)1/2 or c-jun N-terminal kinase MAPKs in human neutrophils from peripheral blood. This is in contrast to other neutrophil agonists such as fMLP, interleukin (IL)-8, or GM-CSF, which stimulate multiple MAPK pathways. Like fMLP and IL-8, CP is capable of stimulating superoxide (O₂^–) production, CD11b expression, and cell polarization in human neutrophils. CP-stimulated O₂^– production is completely dependent on p38-MAPK activation, as determined by sensitivity to the p38-MAPK inhibitor SB203580. In contrast, SB203580 only partially inhibits expression of CD11b and has no effect on cell polarization stimulated by CP. Therefore, CP treatment of neutrophils activates p38-MAPK but has effects independent of p38-MAPK activation. In human embryonic kidney 293 cells, a human kidney epithelial cell line CP stimulates p38-MAPK and modestly activates ERK1/2. The findings define CP as a novel, small molecule, which has little cellular toxicity in vitro. CP has the ability to activate specific MAPK pathways in different cell types and should prove to be an effective agonist in combination with inhibitors to study biological responses regulated by MAPKs.

Key Words: GM-CSF • fMLP • ERK1/2