Dinuclear copper(II) complex as nitric oxide scavenger in a stimulated murine macrophage model.
Nitric oxide is a gaseous, short-living free radical which behaves as an important signaling molecule with pleiotropic capacities including vasodilatation, neurotransmission, and microbial and tumor cell killing, as well as in tissue damage and organ-specific autoimmune disorders. Here, a synthesized, dinuclear copper complex system in vitro obtained by the simple aza-phenolic ligand 2,6-bis[[bis-(2-aminoethyl)amino]methyl]phenol (L) and Cu(II) ion has been used. The stability constants of ligand L with Cu(II) ion were determined through potentiometric measurements in aqueous solution (37.1 +/- 0.1 degrees C, I = 0.15 M of NaCl) to mimic the biological medium. The measurements demonstrated that [Cu(2)H(-1)L(OH)](2+) (DCu) is the predominant species present in solution at pH 7.4. The molecular structure of the ligand in this species permits the cooperation of the two copper ions in assembling the substrate, thus the complex can be used as a receptor for small molecules such as NO. As a biological model, we chose the production of NO catalyzed by inducible nitric oxide synthase obtained from RAW 264.7 murine macrophage cell line stimulated with LPS, which enabled us to prove that NO is coordinated by the DCu complex, modifying its EPR spectra. The coordination of NO with DCu reduces the level of nitrite in the culture medium of stimulated RAW 264.7 macrophages without any inhibition in the expression of iNOS.
Chiarantini
Laura
L
Institute of Biochemistry Giorgio Fornaini, Università degli Studi di Urbino Carlo Bo, Italy. l.chiarantini@uniurb.it
Cerasi
Aurora
A
Giorgi
Luca
L
Formica
Mauro
M
Ottaviani
Maria Francesca
MF
Cangiotti
Michela
M
Fusi
Vieri
V
D000818:Animals; D001372:Aza Compounds / Q000737:chemistry / Q000494:pharmacology; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D003300:Copper / Q000737:chemistry*; D008024:Ligands; D008070:Lipopolysaccharides / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008954:Models, Biological; D008968:Molecular Conformation; D009566:Nitrates / Q000378:metabolism; D009569:Nitric Oxide / Q000737:chemistry / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000187:drug effects / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D009573:Nitrites / Q000378:metabolism; D009942:Organometallic Compounds / Q000737:chemistry*
D001372:Aza Compounds; D008024:Ligands; D008070:Lipopolysaccharides; D009566:Nitrates; D009573:Nitrites; D009942:Organometallic Compounds; D009569:Nitric Oxide; D003300:Copper; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse