ABSTRACT
Mice deficient in the toll-like receptor (TLR) or the myeloid differentiation factor 88 (MyD88) are resistant to acute liver failure (ALF) with sudden death of hepatocytes. Chalcone derivatives from medicinal plants protect from hepatic damages including ALF, but their mechanisms remain to be clarified. Here, we focused on molecular basis of piperidylmethyloxychalcone (PMOC) in the treatment of TLR/MyD88-associated ALF. C57BL/6J mice were sensitized with D-galactosamine (GalN) and challenged with Escherichia coli lipopolysaccharide (LPS, TLR4 agonist) or oligodeoxynucleotide containing unmethylated CpG motif (CpG ODN, TLR9 agonist) for induction of ALF. Post treatment with PMOC sequentially ameliorated hepatic inflammation, apoptosis of hepatocytes, severe liver injury and shock-mediated death in ALF-induced mice. As a mechanism, PMOC inhibited the catalytic activity of TGF-ß-activated kinase 1 (TAK1) in a competitive manner with respect to ATP, displaced fluorescent ATP probe from the complex with TAK1, and docked at the ATP-binding active site on the crystal structure of TAK1. Moreover, PMOC inhibited TAK1 auto-phosphorylation, which is an axis in the activating pathways of nuclear factor-κB (NF-κB) or activating protein 1 (AP1), in the liver with ALF in vivo or in primary liver cells stimulated with TLR agonists in vitro. PMOC consequently suppressed TAK1-inducible NF-κB or AP1 activity in the inflammatory injury, an early pathogenesis leading to ALF. The results suggested that PMOC could contribute to the treatment of TLR/MyD88-associated ALF with the ATP-binding site of TAK1 as a potential therapeutic target.
Subject(s)
Chalcone/pharmacology , Immune System Diseases/complications , Liver Failure, Acute/etiology , Liver Failure, Acute/metabolism , MAP Kinase Kinase Kinases/antagonists & inhibitors , Animals , Chalcone/analogs & derivatives , Chalcone/chemistry , Disease Models, Animal , Gene Expression Regulation/drug effects , Hepatocytes/drug effects , Hepatocytes/immunology , Hepatocytes/metabolism , Hepatocytes/pathology , Liver Failure, Acute/drug therapy , Liver Failure, Acute/pathology , MAP Kinase Kinase Kinases/chemistry , MAP Kinase Kinase Kinases/metabolism , Macrophages/drug effects , Macrophages/immunology , Macrophages/metabolism , Macrophages/pathology , Mice , Models, Molecular , Molecular Conformation , NF-kappa B/metabolism , Phosphorylation , Protective Agents/pharmacology , Protein Binding , Structure-Activity RelationshipABSTRACT
Myeloid differentiation 2 (MD-2) recognizes endotoxin lipopolysaccharide (LPS), which is required for Toll-like receptor 4 (TLR4) activity. MD-2 represents a more attractive therapeutic target than TLR4 for intervention in severe inflammatory disorders due to microbial infection. Here, we suggest MD-2 as a molecular target of nonlipid chalcone in the inhibition of LPS-induced cellular inflammation. A chalcone derivative, 2',4-dihydroxy-6'-isopentyloxychalcone (JSH) competitively displaced LPS from MD-2, and was fitted into the ligand-binding site on the crystal structure of MD-2 under the most energetically favorable simulation. JSH nullified TLR4 activation mechanism and sequentially inhibited nuclear factor-κB (NF-κB) activation that involves the phosphorylation and degradation of inhibitory κBs and the nuclear import and transcriptional activity of NF-κB in LPS-activated macrophages. Moreover, JSH suppressed NF-κB-target inflammatory genes such as inducible nitric oxide synthase, cyclooxygenase-2, interleukin-1ß (IL-1ß) and IL-6. Taken together, this study assigns the chalcone structure as an LPS antagonist binding to MD-2 with therapeutic potential against inflammatory conditions.
Subject(s)
Adaptor Proteins, Signal Transducing/antagonists & inhibitors , Chalcone/pharmacology , Endotoxins/immunology , Endotoxins/toxicity , Immunologic Factors/pharmacology , Toll-Like Receptor 4/antagonists & inhibitors , Adaptor Proteins, Signal Transducing/chemistry , Adaptor Proteins, Signal Transducing/immunology , Adaptor Proteins, Signal Transducing/metabolism , Animals , Cells, Cultured , Lymphocyte Antigen 96 , Macrophages/drug effects , Macrophages/immunology , Mice , Mice, Inbred C3H , Mice, Inbred C57BL , NF-kappa B/antagonists & inhibitors , NF-kappa B/immunology , Nitric Oxide Synthase/antagonists & inhibitors , Protein Binding , Protein Structure, Tertiary , Toll-Like Receptor 4/immunologyABSTRACT
Chroman derivatives exhibited potent inhibitory activity of NF-kappaB. For SAR, the chroman scaffold was modified with an indoline moiety. A series of indoline-2-carboxylic acid N-(substituted)phenylamide derivatives were synthesized to explore their inhibitory activities of NF-kappaB and they were also evaluated for cytotoxicity against various cancer cell lines. Since intermediates with Boc showed outstanding results, various substituents in place of the Boc group were introduced additionally and these compounds were also evaluated for SAR.
Subject(s)
Antineoplastic Agents/chemistry , Benzylamines/chemistry , Indoles/chemistry , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/toxicity , Benzylamines/chemical synthesis , Benzylamines/toxicity , Cell Line, Tumor , Chromans/chemistry , Drug Screening Assays, Antitumor , Humans , NF-kappa B/antagonists & inhibitors , NF-kappa B/metabolism , Structure-Activity RelationshipABSTRACT
alpha-Viniferin, an oligostilbene of trimeric resveratrol, has been reported to have anti-inflammatory potential in carrageenin-induced paw edema or adjuvant-induced arthritis in animal models. However, little is known about the molecular basis. In this study, alpha-viniferin at 3 - 10 microM dose-dependently inhibited interferon (IFN)-gamma-induced Ser(727) phosphorylation of the signal transducer and activation of transcription-1 (STAT-1), a pivotal transcription factor controlling IFN-gamma-targeted genes, in RAW 264.7 macrophages, and also IFN-gamma-induced activation of the extracellular signal-regulated kinase (ERK)-1, a protein kinase upstream of the Ser(727) phosphorylation of STAT-1. However, alpha-viniferin, only at a higher concentration of 10 microM, inhibited Janus kinase 2-mediated Tyr(701) phosphorylation of STAT-1 in the cells. To understand STAT-1-dependent inflammatory responses, we quantified nitric oxide (NO) or chemokines. alpha-Viniferin at 3 - 10 muM dose-dependently inhibited IFN-gamma-induced production of NO, IFN-gamma-inducible protein-10 (IP-10), or the monokine induced by IFN-gamma (MIG) in RAW 264.7 cells and also that of NO in primary macrophages-derived from C57BL/6 mice. Furthermore, alpha-viniferin diminished IFN-gamma-induced protein levels of inducible NO synthase (iNOS), attenuated mRNA levels of iNOS, IP-10, or MIG as well as inhibited promoter activity of the iNOS gene. In conclusion, this study proposes an anti-inflammatory mechanism of alpha-viniferin, down-regulating STAT-1-inducible inflammatory genes via inhibiting ERK-mediated STAT-1 activation in IFN-gamma-stimulated macrophages.
