Cloricromene, a semi-synthetic coumarin derivative, inhibits tumor necrosis factor-alpha production at a pre-transcriptional level.
Cloricromene decreases myocardial infarct size after ischemic-reperfusion injury in vivo, and it has been suggested that this is due to inhibition of tumor necrosis factor-alpha (TNF-alpha). The purpose of this work was to characterize the mechanism of cloricromene-induced inhibition of TNF-alpha in rat macrophages. Cloricromene inhibited lipopolysaccharide-induced TNF-alpha release in a dose-dependent manner (IC(50)=5.9 +/- 0.8 microM). This was not due to cytotoxicity, as cloricromene was well tolerated up to 500 microM. Cloricromene inhibited lipopolysaccharide-induced expression of TNF-alpha mRNA, which suggests a pre-transcriptional effect. We then investigated the early signal transduction pathway triggered by lipopolysaccharide. The binding of lipopolysaccharide to its receptor CD14 activates protein kinase C and nuclear factor-kappaB (NF-kappaB). Cloricromene inhibited NF-kappaB activation in a dose-dependent manner, but affected protein kinase C translocation only slightly. We then established that cloricromene inhibited lipopolysaccharide-induced cellular oxidative activity, which is important for NF-kappaB activation. Our results show that cloricromene interferes with the early signal transduction pathway triggered by lipopolysaccharide.
Corsini
E
E
Laboratory of Toxicology, Department of Pharmacological Sciences, Faculty of Pharmacy, University of Milan, Via Balzaretti 9, 20133, Milan, Italy. emanuela.corsini@unimi.it
Lucchi
L
L
Binaglia
M
M
Viviani
B
B
Bevilacqua
C
C
Monastra
G
G
Marinovich
M
M
Galli
C L
CL
D000818:Animals; D002866:Chromonar / Q000031:analogs & derivatives / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects; D008070:Lipopolysaccharides / Q000494:pharmacology; D016676:Macrophages, Alveolar / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D016328:NF-kappa B / Q000187:drug effects / Q000378:metabolism; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D012333:RNA, Messenger / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D014158:Transcription, Genetic / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism
D008070:Lipopolysaccharides; D016328:NF-kappa B; D010975:Platelet Aggregation Inhibitors; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; C025945:cloricromen; D002866:Chromonar