title: Free thiol group of MD-2 as the target for inhibition of the lipopolysaccharide-induced cell activation.
abstract: MD-2 is a part of the Toll-like 4 signaling complex with an indispensable role in activation of the lipopolysaccharide (LPS) signaling pathway and thus a suitable target for the therapeutic inhibition of TLR4 signaling. Elucidation of MD-2 structure provides a foundation for rational design of inhibitors that bind to MD-2 and inhibit LPS signaling. Since the hydrophobic binding pocket of MD-2 provides little specificity for inhibitors, we have investigated targeting the solvent-accessible cysteine residue within the hydrophobic binding pocket of MD-2. Compounds with affinity for the hydrophobic pocket that contain a thiol-reactive group, which mediates covalent bond formation with the free cysteine residue of MD-2, were tested. Fluorescent compounds 2-(4'-(iodoacetamido)anilino)naphthalene-6-sulfonic acid and N-pyrene maleimide formed a covalent bond with MD-2 through Cys(133) and inhibited LPS signaling. Cell activation was also inhibited by thiol-reactive compounds JTT-705 originally targeted against cholesterol ester transfer protein and antirheumatic compound auranofin. Oral intake of JTT-705 significantly inhibited endotoxin-triggered tumor necrosis factor alpha production in mice. The thiol group of MD-2 also represents the target of environmental or endogenous thiol-reactive compounds that are produced in inflammation.
authors.affiliation: Department of Biotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia.
authors.forename: Mateja
authors.initials: M
authors.lastname: Mancek-Keber
authors.forename: Helena
authors.initials: H
authors.lastname: Gradisar
authors.forename: Melania
authors.initials: M
authors.lastname: Iñigo Pestaña
authors.forename: Guillermo
authors.initials: G
authors.lastname: Martinez de Tejada
authors.forename: Roman
authors.initials: R
authors.lastname: Jerala
mesh_terms: D000577:Amides; D000818:Animals; D001310:Auranofin / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D001665:Binding Sites; D002460:Cell Line; D003545:Cysteine / Q000737:chemistry / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004952:Esters; D005260:Female; D006801:Humans; D008070:Lipopolysaccharides / Q000378:metabolism / Q000494:pharmacology*; D051218:Lymphocyte Antigen 96 / Q000737:chemistry / Q000378:metabolism*; D008301:Maleimides / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D008958:Models, Molecular; D015394:Molecular Structure; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011721:Pyrenes; D015398:Signal Transduction / Q000187:drug effects*; D013438:Sulfhydryl Compounds / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D051193:Toll-Like Receptors / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
chemical_list: D000577:Amides; D004952:Esters; D008070:Lipopolysaccharides; D051218:Lymphocyte Antigen 96; D008301:Maleimides; D011721:Pyrenes; D013438:Sulfhydryl Compounds; D051193:Toll-Like Receptors; D014409:Tumor Necrosis Factor-alpha; C411602:dalcetrapib; D001310:Auranofin; C030984:pyrene; C003944:N-(3-pyrene)maleimide; D003545:Cysteine