title: Acemannan increases NF-κB/DNA binding and IL-6/-8 expression by selectively binding Toll-like receptor-5 in human gingival fibroblasts.
abstract: Acemannan, an acetylated polymannose from Aloe vera, has immunomodulatory effects. We investigated whether acemannan induces IL-6 and -8 expression and NF-κB/DNA binding in human gingival fibroblasts. IL-6 and -8 expression levels were assessed via RT-PCR and ELISA. The NF-κB p50/p65-DNA binding was determined. The structures of acemannan mono-pentamers and Toll-like receptor 5 (TLR5) were simulated. The binding energies between acemannan and TLR5 were identified. We found that acemannan significantly stimulated IL-6/-8 expression at both the mRNA and protein level and significantly increased p50/DNA binding. Preincubation with an anti-TLR5 neutralizing antibody abolished acemannan-induced IL-6/-8 expression and p50/DNA binding, and co-incubation of acemannan with Bay11-7082, a specific NF- κB inhibitor, abolished IL-6/-8 expression. The computer modeling indicated that monomeric/dimeric single stranded acemannan molecules interacted with the TLR5 flagellin recognition sites with a high binding affinity. We conclude that acemannan induces IL-6/-8 expression, and p50/DNA binding in gingival fibroblasts, at least partly, via a TLR5/NF-κB-dependent signaling pathway. Furthermore, acemannan selectively binds with TLR5 ectodomain flagellin recognition sites.
authors.affiliation: Research Unit of Herbal Medicine, Biomaterial and Material for Dental Treatment, Department of Anatomy, Faculty of Dentistry, Chulalongkorn University, Bangkok 10330, Thailand. Electronic address: pasutha.T@chula.ac.th.
authors.forename: Pasutha
authors.initials: P
authors.lastname: Thunyakitpisal
authors.affiliation: Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand. Electronic address: vithaya.r@chula.ac.th.
authors.forename: Vithaya
authors.initials: V
authors.lastname: Ruangpornvisuti
authors.affiliation: Dental Biomaterials Science Program, Graduate School, Chulalongkorn University, Bangkok 10330, Thailand. Electronic address: kawaii_burin@hotmail.com.
authors.forename: Pattrawadee
authors.initials: P
authors.lastname: Kengkwasing
authors.affiliation: Research Unit of Herbal Medicine, Biomaterial and Material for Dental Treatment, Department of Anatomy, Faculty of Dentistry, Chulalongkorn University, Bangkok 10330, Thailand; Department of Material Science, Faculty of Science, Chulalongkorn University, Bangkok, Thailand. Electronic address: nongjaroen2525@gmail.com.
authors.forename: Jaroenporn
authors.initials: J
authors.lastname: Chokboribal
authors.affiliation: Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok, Thailand. Electronic address: spolkit@chula.ac.th.
authors.forename: Polkit
authors.initials: P
authors.lastname: Sangvanich
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology; D004247:DNA / Q000378:metabolism*; D005347:Fibroblasts / Q000187:drug effects*; D005786:Gene Expression Regulation / Q000187:drug effects*; D005881:Gingiva / Q000166:cytology; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics*; D016209:Interleukin-8 / Q000235:genetics*; D008351:Mannans / Q000494:pharmacology*; D016328:NF-kappa B / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects
chemical_list: D000276:Adjuvants, Immunologic; D015850:Interleukin-6; D016209:Interleukin-8; D008351:Mannans; D016328:NF-kappa B; D004247:DNA; C058414:acemannan
keywords: Acemannan; Cytokine; Flagellin binding site; Immunomodulator; NF-κB; Simulation model; Toll-like receptor