Macrophage triggering with cecropin A and melittin-derived peptides induces type II nitric oxide synthase expression.
Triggering of RAW 264.7 cells with a cecropin A-melittin hybrid peptide (CA(1-8)M(1-18)) promoted a rapid rise in the intracellular calcium concentration that was followed, after a lag period of 6 h, by nitric oxide synthesis through the expression of the cytokine-inducible form of nitric oxide synthase (type II NOS or iNOS). The maximal effect was obtained at peptide concentrations in the 2 to 5-microM range. Simultaneous incubation with the peptide and LPS abrogated the nitric oxide synthesis elicited after LPS treatment of the cells. CA(1-8)M(1-18) induced a rapid activation of nuclear factor kappaB as evidenced by the presence of p50/p65 heterodimers of the nuclear factor kappaB/c-Rel family in the nuclei of activated cells. This peptide also activated the reporter activity of cells transfected with a plasmid harboring a 1-kb fragment corresponding to the 5'-flanking region of the murine iNOS gene. CA(1-8)M(1-18) promoted apoptotic cell death at concentrations below 1 to 2 microM, whereas higher concentrations altered the plasma membrane integrity. These results suggest the involvement of multiple intracellular signaling pathways in the mechanism by which this peptide elicits macrophage triggering.
Velasco
M
M
Institute of Biochemistry (CSIC-UCM), Faculty of Pharmacy, Complutense University, Madrid, Spain.
Díaz-Guerra
M J
MJ
Díaz-Achirica
P
P
Andreu
D
D
Rivas
L
L
Boscá
L
L
D000818:Animals; D023181:Antimicrobial Cationic Peptides; D017209:Apoptosis / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004790:Enzyme Induction / Q000187:drug effects; D008262:Macrophage Activation / Q000187:drug effects*; D008555:Melitten / Q000494:pharmacology*; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000096:biosynthesis*; D010455:Peptides / Q000494:pharmacology*; D011993:Recombinant Fusion Proteins
D023181:Antimicrobial Cationic Peptides; D016328:NF-kappa B; D010455:Peptides; D011993:Recombinant Fusion Proteins; D008555:Melitten; C031161:cecropin A; D019001:Nitric Oxide Synthase; D002118:Calcium