ABSTRACT
Neuromyelitis optica (NMO) is a demyelinating autoimmune disease of the optic nerve and spinal cord triggered by binding of NMO-specific immunoglobulinâ G (NMO-IgG) auto-antibodies to the water channel aquaporin-4 (AQP4) in astrocytes. To find potential NMO therapeutics, a screening system was established and used to identify inhibitors of NMO-IgG-mediated complement-dependent cytotoxicity (CDC). The screening of approximately 400 compounds yielded potent hit compounds with inhibitory effects against CDC in U87-MG cells expressing human AQP4. Derivatives of the hit compounds were synthesized and evaluated for their inhibition of CDC. Of the small molecules synthesized, (E)-1-(2-((4-methoxyphenyl)sulfonyl)vinyl)-[4-[(3-trifluoromethyl)phenyl] methoxy]benzene (5 c) showed the most potent activity in both stably transfected U87-MG cells and mice-derived astrocytes. The results of this study suggest that 5 c, which targets NMO-IgG-specific CDC, may be useful as a research tool and a potential candidate for therapeutic development for the treatment of NMO.
Subject(s)
Autoantibodies/immunology , Complement System Proteins/immunology , Cytotoxicity, Immunologic/drug effects , Neuromyelitis Optica/drug therapy , Sulfones/chemistry , Sulfones/pharmacology , Animals , Aquaporin 4/immunology , Astrocytes/drug effects , Astrocytes/immunology , Cell Line , Cells, Cultured , Dogs , Drug Discovery , Humans , Immunoglobulin G/immunology , Mice , Neuromyelitis Optica/immunology , Rats , Sulfones/chemical synthesisABSTRACT
We have synthesized three categories of α,ß-unsaturated carbonyl derivatives and evaluated their MAO-A and MAO-B inhibitory activities. Among them, compound 10b including α,ß-unsaturated ketone group showed the most potent and selective MAO-B inhibitory activity (IC50 human MAO-B 16 nM, >6000-fold selective vs MAO-A) and compound 10b exhibited good reversibility compared with selegiline, a well-known irreversible MAO-B inhibitor. However, both α,ß-unsaturated amide and ester derivatives exhibited weaker MAO-B inhibition potencies. The docking studies provided insights into the possible binding modes and the key interaction sites of the synthesized MAO-B inhibitors.
Subject(s)
Ketones/chemistry , Monoamine Oxidase Inhibitors/chemical synthesis , Monoamine Oxidase/chemistry , Binding Sites , Free Radical Scavengers/chemical synthesis , Free Radical Scavengers/chemistry , Humans , Hydrogen Peroxide/chemistry , Ketones/chemical synthesis , Ketones/metabolism , Kinetics , Molecular Docking Simulation , Monoamine Oxidase/metabolism , Monoamine Oxidase Inhibitors/chemistry , Monoamine Oxidase Inhibitors/metabolism , Protein Binding , Protein Structure, Tertiary , Structure-Activity RelationshipABSTRACT
Imbalance in the antioxidant defense system leads to detrimental consequences, such as neurological disorders. The Nrf2 signaling is known as a main pathway involved in cellular defense system. Nrf2 is a transcription factor that regulates oxidative stress response by inducing expression of various antioxidant enzyme genes. In this study, we screened several pure natural compounds for Nrf2 activator. Among them, shizukahenriol (SZH), isolated from Chloranthus henryi, activated Nrf2, and induced expression of the Nrf2-dependent antioxidant enzymes HO-1, GCLC, and GCLM in BV-2 microglial cells. This natural compound was also effective in suppressing production of inflammatory molecules NO, TNF-α, and inhibition of NF-κB p65 translocation to the nucleus in a dose-dependent manner. We also examined whether SZH rescued the microglial cells from oxidative stress-induced cell death. Pretreatment with SZH dose-dependently attenuated H2O2-induced cytotoxicity in BV-2 microglial cells. These results suggested SZH as a potential neuroprotective agent for neurological disorders.
Subject(s)
Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/pharmacology , Antioxidants/chemistry , Biological Products/chemistry , NF-E2-Related Factor 2/metabolism , Animals , Antioxidants/pharmacology , Cell Line , Hydrogen Peroxide/pharmacology , Mice , Oxidative Stress/drug effects , Reactive Oxygen Species/metabolism , Signal Transduction/drug effects , Transcription Factor RelA/metabolism , Tumor Necrosis Factor-alpha/metabolismABSTRACT
BACKGROUND/AIMS: The sodium/bicarbonate transporter NBCn1 plays an essential role in intracellular pH regulation and transepithelial HCO(3)(-) movement in the body. NBCn1 also has sodium channel-like activity uncoupled to Na/HCO(3) cotransport. We previously reported that NBCn1 interacts with the postsynaptic density protein PSD-95 in the brain. Here, we elucidated the structural determinant and functional consequence of NBCn1/PSD-95 interaction. RESULTS: In rat hippocampal CA3 neurons, NBCn1 was localized to the postsynaptic membranes of both dendritic shafts and spines and occasionally to the presynaptic membranes. A GST/NBCn1 fusion protein containing the C-terminal 131 amino acids of NBCn1 pulled down PSD-95 from rat brain lysates, whereas GST/NBCn1-ΔETSL (deletion of the last four amino acids) and GST/NBCn2 (NCBE) lacking the same ETSL did not. NBCn1 and PSD-95 were coimmunoprecipitated in HEK 293 cells, and their interaction did not affect the efficacy of PSD-95 to bind to the NMDA receptor NR2A. PSD-95 has negligible effects on intracellular pH changes mediated by NBCn1 in HEK 293 cells and Xenopus oocytes. However, PSD-95 increased an ionic conductance produced by NBCn1 channel-like activity. This increase was abolished by NBCn1-ΔETSL or by the peptide containing the last 15 amino acids of NBCn1. CONCLUSION: Our data suggest that PSD-95 interacts with NBCn1 and increases its channel-like activity while negligibly affecting Na/HCO(3) cotransport. The possibility that the channel-like activity occurs via an intermolecular cavity of multimeric NBCn1 proteins is discussed.
