pp38 and total p38 protein were detected via western analysis. Surprisingly, with the exception of DCLF/TNFα exposure, treatment with the p38 inhibitor SB203580 enhanced cytotoxicity mediated by AA derivative/TNFα exposure in the presence and absence of IFNγ (P38 plays a protective role in NSAID/cytokine-induced cytotoxicity. Representative blots are shown. NSAID-treated patients compared to 12 per 100 person years in non-NSAID exposed patients. Treatment with a representative AA or PA derivative induced activation of the MAPKs c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and p38. Please check for further notifications by email. Cells were also incubated in the presence and absence of the pan-caspase inhibitor ZVAD-FMK (40 μM). Mechanisms of IDILI are unknown, but immune responses are suspected to underlie them. Protein extracts were collected 18 h after treatment. <>
HepG2 cells were treated with (A) a representative PA derivative (IBU: 6 mM) alone or in combination with TNFα and/or IFNγ. stream
pSTAT 1 (Tyrosine 701), pSTAT-1 (Serine 727), and α-Tubulin protein levels, were detected via western analysis. We tested the hypothesis that caspases and MAPKs are involved in NSAID/cytokine-induced cytotoxicity. HepG2 cells were treated with NSAIDs that have (A, B) or do not have (C) IDILI liability alone or in combination with TNFα (10 ng/ml) and/or IFNγ (10 ng/ml). Cytotoxicity was measured 24 h later. An AA derivative but not a PA derivative enhanced IFNγ-mediated activation of STAT-1, and this enhancement was ERK-dependent. a, significantly different from VEH; b, significantly different from TNFα; c, significantly different from IFNγ; d, significantly different from control. Representative blots are shown. (C) Cells were treated with a representative AA derivative (DCLF: 250 µM) or a representative PA derivative (IBU: 6 mM) in the presence or absence of SP600125 for 12 h, and p-JNK and total JNK protein were detected via western analysis. These results are consistent with what has been reported previously in studies involving animal models of drug/inflammatory stress-induced liver injury (To gain insight into the mechanism underlying NSAID/cytokine-induced cytotoxic synergy, the roles of caspases and MAPKs were examined. Thank you for submitting a comment on this article. NSAID/cytokine combinations were also incubated in the presence and absence of the p38 inhibitor SB203580 (20 μM). Cytotoxicity was measured 24 h later. Search for other works by this author on:
Abbreviations: VEH, vehicle; TNF, tumor necrosis factor-alpha; IFN, interferon gamma; TI, tumor necrosis factor-alpha and interferon-gamma; DCLF, diclofenac; IBU, ibuprofen.We next examined the involvement of JNK in NSAID/cytokine-induced cytotoxicity. Immunotoxicity of an Electrochemically Fluorinated Aqueous Film-Forming Foam Representive blots are shown. a, significantly different from VEH; b, significantly different from TNFα; c, significantly different from Control; d, significantly different from DCLF (without inhibitor). Data were analyzed via a 1-way or 2-way analysis of variance (ANOVA). Aspirin, an NSAID that is not associated with IDILI, did not synergize with any combination of cytokines to kill cells. Although these 2 subclasses differed in the manner in which they synergized with the cytokines, within subclass they responded similarly to each other. c, significantly different from Control within a cytokine treatment. Treatment with SP600125, an inhibitor of JNK activation, significantly reduced cytotoxicity mediated by cytokines in combination with NSAIDs containing an AA moiety (JNK is involved in the NSAID/cytokine-induced cytotoxic interaction. b, significantly different from IFNγ within an NSAID treatment. pp38 and total p38 protein were detected via western analysis. Upon phosphorylation, STAT-1 dimerizes and translocates to the nucleus, where it binds to specific DNA sequences (In stark contrast to DCLF, treatment with IBU prevented IFNγ-mediated phosphorylation of STAT-1 at both Tyr 701 and Ser 727 (In summary, NSAIDs associated with IDILI synergize with TNFα to cause death of HepG2 cells. Caspase enzymes are crucial to the initiation of apoptosis (Prolonged activation of JNK is associated with signaling through pathways leading to cell death (In contrast to the AA derivatives, JNK inhibition did not affect cytotoxicity mediated by PA derivative/cytokine combinations (ERK phosphorylation is typically associated with activating cell survival signaling pathways; however, it has become clear that under some conditions, ERK activates cell death pathways (The involvement of p38 in drug/cytokine-induced cytotoxic synergy has not been reported. a, significantly different from VEH within an NSAID treatment.