title: Identification and characterization of oligonucleotides that inhibit Toll-like receptor 2-associated immune responses.
abstract: Toll-like receptors (TLRs) play important roles in the immune responses against invading microorganisms. Development of TLR antagonists is recognized as a promising direction in suppressing the associated inflammatory reactions of the TLRs. Aptamers are single-stranded RNA or DNA molecules isolated through an in vitro selection process. Using a novel molecular evolution strategy that combines immunoprecipitation (IP) with systematic evolution of ligands by exponential enrichment (SELEX), we developed an IP-SELEX selection method to facilitate the screening of high-affinity aptamers for the Toll-like receptor 2 (TLR2). Also, human TLR2 functional aptamers were identified and characterized using NF-kappaB reporter assays. Among the functional aptamers, the most effective, AP177, with a dissociation constant of 73 pM, was characterized with TLR2-expressing cells challenged with bacterial cells and purified ligands. The aptamer could effectively antagonize TLR2, significantly inhibit NF-kappaB activity, and suppress the secretion of the cytokines by >80%. In addition, the precise region within the functional aptamer that specifically bound TLR2 was resolved using aptamer microarray analysis. The results of functional assays showed that AP177 acted as a TLR2 antagonist and may hold therapeutic potential in the treatment of diseases related to dysregulated TLR2 immune responses.
authors.affiliation: Department of Microbiology, National Taiwan University, Taipei, Taiwan.
authors.forename: Yi-Chung
authors.initials: YC
authors.lastname: Chang
authors.forename: Wei-Chen
authors.initials: WC
authors.lastname: Kao
authors.forename: Wei-Ya
authors.initials: WY
authors.lastname: Wang
authors.forename: Wan-Yi
authors.initials: WY
authors.lastname: Wang
authors.forename: Ruey-Bing
authors.initials: RB
authors.lastname: Yang
authors.forename: Konan
authors.initials: K
authors.lastname: Peck
mesh_terms: D052157:Aptamers, Nucleotide; D002460:Cell Line; D019020:Directed Molecular Evolution / Q000379:methods; D055808:Drug Discovery; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D006801:Humans; D007109:Immunity / Q000187:drug effects*; D009841:Oligonucleotides / Q000494:pharmacology*; D052156:SELEX Aptamer Technique; D051195:Toll-Like Receptor 2 / Q000037:antagonists & inhibitors* / Q000276:immunology
chemical_list: D052157:Aptamers, Nucleotide; D009841:Oligonucleotides; C495342:TLR2 protein, human; D051195:Toll-Like Receptor 2