The ketolide antimicrobial agent HMR-3004 inhibits neutrophil superoxide production by a membrane-stabilizing mechanism.
We have investigated the membrane-stabilizing potential of the prototype ketolide antimicrobial agent, HMR-3004 (3.75-125 microM), as well as the effects of this agent on the production of superoxide by human neutrophils activated with FMLP, the calcium ionophore A23187, phorbol 12-myristate 13-acetate (PMA) or opsonized zymosan (OZ), each of which uses different transductional mechanisms to activate NADPH-oxidase. Membrane-stabilizing activity was investigated using a hemolytic procedure, while superoxide production was assayed by lucigenin-enhanced chemiluminescence. At concentrations of 3.75 microM and greater, HMR-3004 caused dose-related inhibition of superoxide production by neutrophils activated by all four stimuli of membrane-associated oxidative metabolism, which was not associated with cytotoxicity or superoxide-scavenging activity. At the same concentrations, HMR-3004 antagonized the hemolytic actions of the membrane-disruptive bioactive phospholipids, lysophosphatidylcholine (LPC), platelet-activating factor (PAF) and lyso-PAF. A mechanistic relationship between the membrane-stabilizing and the anti-oxidative properties of HMR-3004 was suggested by the observation that treatment of neutrophils with non-cytolytic concentrations of LPC antagonized the inhibitory effects of the ketolide on superoxide production by these cells. These membrane-stabilizing, anti-oxidative activities of HMR-3004 suggest that in addition to its antimicrobial properties, this agent possesses anti-inflammatory properties which are superior to those of the presently available macrolide and azalide agents.
Department of Immunology, University of Pretoria, South Africa.
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Mokgobu
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Theron
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Anderson
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Feldman
D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002462:Cell Membrane / Q000187:drug effects; D006801:Humans; D048628:Ketolides; D008244:Lysophosphatidylcholines / Q000494:pharmacology; D018942:Macrolides; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D048628:Ketolides; D008244:Lysophosphatidylcholines; D018942:Macrolides; C105420:RU 64004; D013481:Superoxides; D009240:N-Formylmethionine Leucyl-Phenylalanine; D013755:Tetradecanoylphorbol Acetate