title: Toll-like receptors required for dermatophagoides farinae to activate NF-κB.
abstract: Body and excrement extracts from Dermatophagoides farinae were used to study stimulation of Toll-like receptors (TLRs). The excrement extract stimulated nuclear factor (NF)-κB-dependent reporter activity to an extent similar to lipopolysaccharide (LPS) in a mouse macrophage cell line, J774A.1, but the activity of the body extract was negligible. The excrement extract also activated NF-κB in HEK293 cells expressing TLR1/TLR2, TLR2/TLR6 and CD14/TLR4/MD-2, whereas no activation was observed in cells expressing TLR3, TLR5, TLR7, TLR8 or TLR9. Although the excrement extract required co-expression of CD14, TLR4 and MD-2 in HEK293 cells to activate NF-κB, efficient activation was still observed in I-13.35 cells, a bone-marrow macrophage cell line established from LPS-hypo-responsive C3H/HeJ mice. The excrement extract activated NF-κB in HEK293 cells expressing TLR2 alone, but the activation was significantly increased by co-expression of CD14. Polymyxin B inhibited CD14/TLR4/MD-2- and CD14/TLR2-mediated activation of NF-κB but not the activation in I-13.35 cells. These results indicate that CD14/TLR4/MD-2-dependent and CD14/TLR2-dependent mechanisms are involved in the activation of NF-κB by the excrement extract of D. farinae and suggest that the extract also contains substances that activate NF-κB through non-TLR-mediated mechanisms.
authors.affiliation: Research Institute of Pharmaceutical Sciences, Musashino University.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Kitajima
authors.forename: Masashi
authors.initials: M
authors.lastname: Muroi
authors.forename: Naomi
authors.initials: N
authors.lastname: Yamashita
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Tanamoto
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002460:Cell Line; D040001:Dermatophagoides farinae; D057809:HEK293 Cells; D006801:Humans; D006967:Hypersensitivity / Q000378:metabolism*; D018950:Lipopolysaccharide Receptors / Q000378:metabolism; D008070:Lipopolysaccharides; D051218:Lymphocyte Antigen 96 / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008809:Mice, Inbred C3H; D016328:NF-kappa B / Q000378:metabolism*; D011112:Polymyxin B / Q000494:pharmacology; D051195:Toll-Like Receptor 2 / Q000378:metabolism*; D051197:Toll-Like Receptor 4 / Q000378:metabolism*
chemical_list: D000900:Anti-Bacterial Agents; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; C411728:Ly96 protein, mouse; D051218:Lymphocyte Antigen 96; D016328:NF-kappa B; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D011112:Polymyxin B