Manganese-based Superoxide Dismutase Mimetics Inhibit Neutrophil Infiltration in Vivo
| Autor: | Dennis P. Riley, D. J. Fretland, Una S. Ryan, Randy H. Weiss, David A. Baron |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Male
Colon Neutrophils Biochemistry Proinflammatory cytokine Superoxide dismutase Mice Structure-Activity Relationship chemistry.chemical_compound Acetic acid Superoxides In vivo Organometallic Compounds medicine Animals Superoxide dismutase mimetics Molecular Biology Manganese Dose-Response Relationship Drug biology Superoxide Dismutase Superoxide Molecular Mimicry Free Radical Scavengers Cell Biology Colitis medicine.disease In vitro Chemotaxis Leukocyte chemistry biology.protein Infiltration (medical) |
| Zdroj: | Journal of Biological Chemistry. 271:26149-26156 |
| ISSN: | 0021-9258 |
| DOI: | 10.1074/jbc.271.42.26149 |
| Popis: | In a previous study (Hardy et al. (1994) J. Biol. Chem. 269, 18535-18540), we observed that the manganese-based superoxide dismutase mimetic Mn(II)-dichloro(1,4,7,10,13-pentaazacyclopentadecane) (MnPAM) inhibited neutrophil-mediated cell injury in vitro. We have extended these studies with the low molecular weight superoxide dismutase mimic to evaluate the role of superoxide in neutrophil-mediated tissue injury in vivo. In a dose-dependent manner, MnPAM inhibited colonic tissue injury and neutrophil accumulation into the colonic tissue induced by the intracolonic instillation of dilute aqueous acetic acid in mice. Tissue injury was assessed by visual and histological analysis. Neutrophil infiltration was determined by tissue myeloperoxidase activity and confirmed by histological analysis. Two novel Mn(II) dichloro complexes of the carbon-substituted macrocycles 2-methyl-1,4,7,10,13-pentaazacyclopentadecane (MnMAM) and 2-(2-methylpropyl)-1,4,7,10,13-pentaazacyclopentadecane (MnBAM) effectively catalyzed the dismutation of superoxide with catalytic rate constants (kcat) of 3. 31 x 10(7) M-1 s-1 and 1.91 x 10(7) M-1 s-1, respectively, as determined by stopped-flow kinetic analysis at pH 8.1 and 21 degrees C. The superoxide dismutase mimetics MnMAM and MnBAM also attenuated dilute aqueous acetic acid-induced tissue injury and neutrophil infiltration into colonic tissue; however, two Mn(II) complexes that had little or no detectable SOD activity (kcat/= 0.1 x 10(7) M-1 s-1), specifically the Mn(II) dichloro complexes of 1,4,7,10,13-pentaazacyclohexadecane and 1,4,7,11,14-pentaazacycloheptadecane, failed to inhibit the colonic tissue injury or infiltration of neutrophils in mice treated intracolonically with dilute aqueous acetic acid. These results are consistent with a proinflammatory role for superoxide in the mediation of neutrophil infiltration in vivo. |
| Databáze: | OpenAIRE |
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