title: Toll-like receptor (TLR)-7 and -8 modulatory activities of dimeric imidazoquinolines.
abstract: Toll-like receptors (TLRs) are pattern recognition receptors that recognize specific molecular patterns present in molecules that are broadly shared by pathogens but are structurally distinct from host molecules. The TLR7-agonistic imidazoquinolines are of interest as vaccine adjuvants given their ability to induce pronounced Th1-skewed humoral responses. Minor modifications on the imidazoquinoline scaffold result in TLR7-antagonistic compounds which may be of value in addressing innate immune activation-driven immune exhaustion observed in HIV. We describe the syntheses and evaluation of TLR7 and TLR8 modulatory activities of dimeric constructs of imidazoquinoline linked at the C2, C4, C8, and N(1)-aryl positions. Dimers linked at the C4, C8, and N(1)-aryl positions were agonistic at TLR7; only the N(1)-aryl dimer with a 12-carbon linker was dual TLR7/8 agonistic. Dimers linked at C2 position showed antagonistic activities at TLR7 and TLR8; the C2 dimer with a propylene spacer was maximally antagonistic at both TLR7 and TLR8.
authors.affiliation: Department of Medicinal Chemistry, University of Kansas, Multidisciplinary Research Building, Room 320D, 2030 Becker Drive, Lawrence Kansas 66047, United States.
authors.forename: Nikunj M
authors.initials: NM
authors.lastname: Shukla
authors.forename: Cole A
authors.initials: CA
authors.lastname: Mutz
authors.forename: Subbalakshmi S
authors.initials: SS
authors.lastname: Malladi
authors.forename: Hemamali J
authors.initials: HJ
authors.lastname: Warshakoon
authors.forename: Rajalakshmi
authors.initials: R
authors.lastname: Balakrishna
authors.forename: Sunil A
authors.initials: SA
authors.lastname: David
mesh_terms: D019281:Dimerization; D017930:Genes, Reporter; D006801:Humans; D007093:Imidazoles / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D007113:Immunity, Innate; D016898:Interferon-alpha / Q000096:biosynthesis; D053583:Interleukin-1beta / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D016209:Interleukin-8 / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D011804:Quinolines / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D013329:Structure-Activity Relationship; D051199:Toll-Like Receptor 7 / Q000819:agonists* / Q000037:antagonists & inhibitors*; D051200:Toll-Like Receptor 8 / Q000037:antagonists & inhibitors*; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000096:biosynthesis
chemical_list: D007093:Imidazoles; D016898:Interferon-alpha; D053583:Interleukin-1beta; D016209:Interleukin-8; D011804:Quinolines; D051199:Toll-Like Receptor 7; D051200:Toll-Like Receptor 8; D014409:Tumor Necrosis Factor-alpha