Protease inhibitors protect macrophages from lipopolysaccharide-induced cytotoxicity: possible role for NF-kappaB.
Recent studies suggest lipopolysaccharide (LPS) mediated cell death as underlying mechanism of hyporesponsiveness and dysfunction of macrophages in the late phase of septic shock. In the present study LPS (0.001 - 30 microg/ml) caused a concentration-dependent toxicity in the macrophage cell line (J774.1A) within 24 h. The toxicity induced by LPS (1 microg/ml) was completely inhibited by the serine protease inhibitors, N-alpha-tosyl-L-phenylalanine chloromethyl ketone (TPCK) and N-alpha-tosyl-L-lysine chloromethyl ketone (TLCK) as measured by the mitochondrial-dependent oxidation of 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromid (MTT) to formazan. These inhibitors antagonize the activation of nuclear transcription factor-kappaB (NF-kappaB) indirectly by inhibiting I kappaB alpha-protease. SN50, a direct inhibitor of NF-kappaB translocation into the nucleus also protected macrophages from LPS-mediated toxicity. We conclude from these data that the early phase signal transduction pathway leading to LPS-mediated cytotoxicity in macrophages involves the activation of NF-kappaB. Thus, I kappaB alpha-protease inhibitors might serve as therapeutical agents to maintain macrophage viability during sepsis and to prevent sepsis-induced immune dysfunction.
Abate
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Department of Pharmacology and Toxicology, School of Pharmacy, Martin Luther University, Halle (Saale), Germany. abate@pharmazie.uni-halle.de
Schröder
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D000595:Amino Acid Sequence; D000818:Animals; D016923:Cell Death / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000378:metabolism; D004347:Drug Interactions; D020672:I-kappa B Proteins; D008070:Lipopolysaccharides / Q000633:toxicity*; D008262:Macrophage Activation / Q000187:drug effects / Q000502:physiology; D008264:Macrophages / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D051379:Mice; D008969:Molecular Sequence Data; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000502:physiology*; D010455:Peptides / Q000378:metabolism; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D014107:Tosyllysine Chloromethyl Ketone / Q000494:pharmacology*; D014108:Tosylphenylalanyl Chloromethyl Ketone / Q000494:pharmacology*
D004268:DNA-Binding Proteins; D020672:I-kappa B Proteins; D008070:Lipopolysaccharides; D016328:NF-kappa B; C000606205:Nfkbia protein, mouse; D010455:Peptides; C118258:SN50 peptide; D015842:Serine Proteinase Inhibitors; D000072000:NF-KappaB Inhibitor alpha; D014107:Tosyllysine Chloromethyl Ketone; D014108:Tosylphenylalanyl Chloromethyl Ketone