Neutrophils play a key role in innate immunity, and the identification of new stimuli that stimulate neutrophil activity is a very important issue. In this study, we identified three novel peptides by screening a synthetic hexapeptide combinatorial library. The identified peptides GMMWAI, MMHWAM, and MMHWFM caused an increase in intracellular Ca2+ in a concentration-dependent manner via phospholipase C activity in human neutrophils. The three peptides acted specifically on neutrophils and monocytes and not on other non-leukocytic cells. As a physiological characteristic of the peptides, we observed that the three peptides induced chemotactic migration of neutrophils as well as stimulated superoxide anion production. Studying receptor specificity, we observed that two of the peptides (GMMWAI and MMHWFM) acted on formyl peptide receptor (FPR)1 while the other peptide (MMHWAM) acted on FPR2. Since the three novel peptides were specific agonists for FPR1 or FPR2, they might be useful tools to study FPR1- or FPR2-mediated immune response and signaling.
Animals ; Calcium/metabolism ; Cell Line ; Cells, Cultured ; Chemotaxis, Leukocyte/drug effects ; Humans ; Mice ; NIH 3T3 Cells ; Neutrophils/*cytology/*drug effects ; PC12 Cells ; Peptides/*pharmacology ; Rats ; Receptors, Formyl Peptide/agonists

Nordy is a synthesized chrial compound. To investigate the effects of nordy (25 - 100 micromol x L(-1)) on the function of formylpeptide receptor (FPR) of malignant human glioma cells, human glioblastoma cell line U87 was used to detect its proliferation, migration, calcium mobilization, vascular endothelial growth factor (VEGF) mRNA and protein levels after activation of FPR by its agonist N-formyl-methionyl-leucyl-phenylalanine (fMLF). Cell proliferation, migration ability, VEGF mRNA, VEGF protein and calcium mobilization were evaluated by cell counting, chemotaxis assay, RT-PCR, ELISA and spectrometry. Nordy (50 - 100 micromol x L(-1)) potently inhibited the proliferation, migration and calcium mobilization of U87 cells induced by fMLF (P < 0.05). Moreover, 100 micromol x L(-1) nordy showed a significantly impaired VEGF mRNA expression and protein secretion induced by fMLF (P < 0.05). Nordy could inhibit FPR functioning in glioma cell proliferation, migration and angiogenesis, which might be a possible mechanism of its anti-cancer effects.
Antineoplastic Agents ; pharmacology ; Calcium ; metabolism ; Cell Line, Tumor ; Cell Movement ; drug effects ; Cell Proliferation ; drug effects ; Dose-Response Relationship, Drug ; Enzyme-Linked Immunosorbent Assay ; Glioblastoma ; genetics ; metabolism ; pathology ; Humans ; Masoprocol ; analogs & derivatives ; pharmacology ; N-Formylmethionine Leucyl-Phenylalanine ; pharmacology ; RNA, Messenger ; biosynthesis ; genetics ; Receptors, Formyl Peptide ; agonists ; metabolism ; physiology ; Reverse Transcriptase Polymerase Chain Reaction ; Spectrophotometry ; methods ; Vascular Endothelial Growth Factor A ; biosynthesis ; genetics