concanavalin-a and benzyloxycarbonylvalyl-alanyl-aspartyl-fluoromethyl-ketone

Concanavalin A (con A)-induced hepatitis is an immunomediated disease in which assembly of CD4(+) T cells and T helper (Th)1-like cytokines causes Fas-mediated liver cell death. Nitric oxide (NO) modulates Th1 response in vitro. NCX-4016 is an NO-aspirin derivative that spares the gastrointestinal tract and shares molecular targets with NO. The aim of this study was to investigate whether this NO-aspirin modulates Th1-like response induced by con A.. BALB/c mice were injected with 0.3 mg con A per mouse alone or in combination with NO-aspirin (18-100 mg/kg) or aspirin (10-55 mg/kg).. NO-aspirin, but not aspirin, caused a dose-dependent protection against liver damage induced by con A. At a dose of 100 mg/kg, NO-aspirin caused a 40%-80% reduction of interleukin (IL)-1beta, IL-12, IL-18, interferon (IFN)-gamma, and tumor necrosis factor alpha production without affecting cytokine messenger RNA expression. NO-aspirin prevented Fas, Fas ligand, and IL-2 receptor up-regulation on spleen lymphocytes and Fas ligand on hepatocytes and caused the S-nitrosylation/inhibition of IL-1beta-converting enzyme-like cysteine proteases (caspases) involved in the processing and maturation of IL-1beta and IL-18. IL-18 immunoneutralization prevented IFN-gamma release and protected from liver injury induced by con A. In contrast to a selective caspase 1 inhibitor, zVAD.FMK, a pancaspase inhibitor, prevented IFN-gamma release and protected the liver from injury.. Th1-like response induced by con A is mediated by IL-18 and requires activation of multiple caspases. NCX-4016 causes the S-nitrosylation/inhibition of caspases involved in cytokine production. Inhibition of Th1-like response is a new anti-inflammatory mechanism of action of NO-aspirin.

Topics: Amino Acid Chloromethyl Ketones; Animals; Aspirin; Caspase 1; Caspase 3; Caspase Inhibitors; Caspases; Chemical and Drug Induced Liver Injury; Concanavalin A; Cysteine Proteinase Inhibitors; Cytokines; Fas Ligand Protein; fas Receptor; Interferon-gamma; Interleukin-18; Interleukins; Liver; Membrane Glycoproteins; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Platelet Aggregation Inhibitors; Receptors, Interleukin-2; RNA, Messenger; Spleen; T-Lymphocytes; Th1 Cells; Transcription, Genetic; Up-Regulation

Several models of tumor necrosis factor (TNF)/TNF-receptor 1 (TNF-R1)-dependent liver injury in mice were investigated with respect to caspase-3-like protease activation representing a pivotal mechanism of apoptotic cell death. Injection of TNF or T-cell-activating agents (i.e., agonistic anti-CD3 antibody or staphylococcal enterotoxin B [SEB]) into galactosamine (GalN)-sensitized mice caused TNF/TNF-R1-dependent liver injury. Intravenous concanavalin A (Con A) alone induced TNF-mediated hepatotoxicity dependent on both TNF-R1 and TNF-R2. Hepatic caspase-3-like proteases were activated in GalN/TNF, GalN/anti-CD3, or GalN/SEB-treated mice, but not in Con A-treated mice. Consistently, the broad-spectrum caspase inhibitor, benzoyloxycarbonyl-val-ala-asp-fluoromethylketone (zVADfmk), prevented TNF-mediated hepatotoxicity in all GalN-dependent models, but failed to protect against Con A. Under transcriptional arrest, however, Con A induced TNF-R1-dependent, but not TNF-R2-dependent, activation of caspase-3-like proteases, and zVADfmk prevented animals from Con A-mediated liver injury under this condition. Histological analysis revealed distinct differences between Con A- and GalN/Con A-induced liver injury regarding apoptotic morphology of hepatocytes. We conclude that impaired transcription induces a switch of Con A hepatotoxicity toward a caspase-3-like protease-dependent pathway. The observation that the functional state of the transcriptional machinery decides whether TNF-driven hepatocyte apoptosis involves activation of caspase-3-like proteases or alternative signaling pathways in vivo might be of relevance for the immunopathology of the liver.

Topics: Amino Acid Chloromethyl Ketones; Animals; Antibodies; Antigens, CD; Apoptosis; Caspase 3; Caspases; CD3 Complex; Concanavalin A; Cysteine Proteinase Inhibitors; Enterotoxins; Enzyme Activation; Galactosamine; Lipid Metabolism; Liver; Male; Mice; Mice, Inbred BALB C; Receptors, Tumor Necrosis Factor; Receptors, Tumor Necrosis Factor, Type I; Receptors, Tumor Necrosis Factor, Type II; Specific Pathogen-Free Organisms; Staphylococcus aureus; Tumor Necrosis Factor-alpha

The objective of the present study was to determine the effects of concanavalin A (Con A) administration on the interleukin 1beta converting enzyme (ICE) activity and CPP32-like activity in mouse liver. Treatment with Con A (0.2 mg/mouse, i.v.) caused an elevated plasma alanine aminotransferase (ALT) level at 8 hr after Con A injection. ICE activity was decreased at 8 and 24 hr after Con A treatment. In contrast, CPP32-like activity was increased at 24 hr after Con A injection. Since CPP32-like activity was induced after ALT had increased, the induction of CPP32-like activity may not be involved in Con A-induced hepatitis.

Topics: Amino Acid Chloromethyl Ketones; Animals; Caspase 1; Caspase 3; Caspases; Chemical and Drug Induced Liver Injury; Concanavalin A; Cysteine Proteinase Inhibitors; Disease Models, Animal; Enzyme Induction; Female; Liver; Mice; Mice, Inbred BALB C

Two lipophilic derivatives of caffeic acid which inhibit lipoxygenase, caffeic acid phenethyl ester (CAPE) and N,N'-dicyclohexyl-O-(3,4-dihydroxycinnamoyl)-isourea (DCHCU), reduced the proliferative response of murine splenocytes to concanavalin A in vitro. Both CAPE and DCHCU induced apoptosis in murine thymocyte cultures as verified by flow cytometry and by visualisation of DNA with acridine orange staining. CAPE-induced apoptosis was inhibited by z-VAD-fmk, an inhibitor of the interleukin-1beta-converting enzyme family of cysteine proteases. We suggest that the lipoxygenase pathway of arachidonic acid metabolism plays a role in regulating lymphocyte responses such as proliferation and apoptosis.

Topics: Amino Acid Chloromethyl Ketones; Animals; Apoptosis; Caffeic Acids; Caspase 1; Cell Division; Cells, Cultured; Concanavalin A; Cysteine Endopeptidases; Cysteine Proteinase Inhibitors; Lipoxygenase Inhibitors; Lymphocytes; Male; Mice; Mice, Inbred C57BL; Phenylethyl Alcohol; Propolis; Quercetin; T-Lymphocytes; Urea