TY - JOUR T1 - Aurintricarboxylic Acid Protects against Cell Death Caused by Lipopolysaccharide in Macrophages by Decreasing Inducible Nitric-Oxide Synthase Induction via IκB Kinase, Extracellular Signal-Regulated Kinase, and p38 Mitogen-Activated Protein Kinase Inhibition JF - Molecular Pharmacology JO - Mol Pharmacol SP - 90 LP - 101 DO - 10.1124/mol.62.1.90 VL - 62 IS - 1 AU - Chin-Ju Tsi AU - Yee Chao AU - Ching-Wen Chen AU - Wan Wan Lin Y1 - 2002/07/01 UR - http://molpharm.aspetjournals.org/content/62/1/90.abstract N2 - To elucidate the mechanisms involved in cell protection by aurintricarboxylic acid (ATA), an endonuclease inhibitor, high nitric oxide (NO)-induced macrophage apoptosis was studied. In RAW 264.7 macrophages, a high level of NO production accompanied by cell apoptosis was apparent with lipopolysaccharide (LPS) treatment. Direct NO donor sodium nitroprusside (SNP) also dramatically induced cell death, with an EC50 of 1 mM. Coincubation of ATA (1–500 μM) in LPS-stimulated RAW 264.7 cells resulted in a striking reduction of NO production and cell apoptosis, whereas only a partial cell protection was achieved in response to SNP. This suggests that abrogation of inducible nitric-oxide synthase (iNOS)-dependent NO production might contribute to ATA protection of LPS-treated cells. Immunoblotting and reverse transcription-polymerase chain reaction analysis revealed that ATA down-regulated iNOS protein through transcriptional inhibition of iNOS gene expression but was unrelated to iNOS protein stability. ATA not only inhibited nuclear factor-κB (NF-κB) activation through impairment of the targeting and degradation of IκBs but also reduced LPS-induced activator protein-1 (AP-1) activation. These actions of ATA were not caused by the influence on LPS binding to macrophage membrane. Kinase assays indicated that ATA inhibited IκB kinase (IKK), extracellular signal-regulated kinase (ERK), and p38 mitogen-activated protein kinase (MAPK) activity both in vivo and in vitro, suggesting a direct interaction between ATA and these signaling molecules. Taken together, these results provide novel action targets of ATA and indicate that ATA protection of macrophages from LPS-mediated cell death is primarily the result of its inhibition of NO production, which closely relates to the inactivation of NF-κB and AP-1 and inhibition of IKK, ERK and p38 MAPK. ER -