title: Dual oxidase 2 is essential for house dust mite-induced pro-inflammatory cytokine production in human keratinocytes.
abstract: House dust mites (HDMs) are known to trigger chronic inflammation through Toll-like receptors (TLRs) and their signalling cascades. In this study, we found that TLR2 ligation by HDMs induced the activation of dual oxidase 2 (Duox2) and nuclear factor-κB (NF-κB), leading to the production of pro-inflammatory cytokines in human keratinocytes. Stimulation of human keratinocytes with HDMs resulted in increases in interleukin-8 (IL-8) and chemokine (C-C motif) ligand 20 (CCL20) levels. However, pro-inflammatory cytokine production was abolished in keratinocytes transfected with TLR2 siRNA, indicating that HDM-induced cytokine production was mediated via TLR2 signalling. We also examined the function of Duox1/2 isozymes, which are primarily expressed in keratinocytes, in HDM-mediated pro-inflammatory cytokine production. Human keratinocytes transfected with control siRNA or Duox1 siRNA showed no inhibition of IL-8 or CCL20 production in response to HDMs, whereas the silencing of Duox2 expression resulted in a failure to induce cytokine production. Moreover, the phosphorylation and nuclear localization of RelA/p65, a component of NF-κB, were induced by HDMs in human keratinocytes. Transfection of human keratinocytes with TLR2 siRNA or Duox2 siRNA resulted in the complete abolishment of RelA/p65 nuclear localization in response to HDMs. Taken together, these results indicate that the HDM-dependent TLR2-Duox2 signalling axis indeed promotes NF-κB activation, which induces IL-8 and CCL20 production and mediates epidermal keratinocyte inflammation.
authors.affiliation: Department of Life Sciences, Ewha Womans University, Seoul, Korea.
authors.forename: Eunbi
authors.initials: E
authors.lastname: Ko
authors.affiliation: Bioscience Research Institute, Amorepacific Corporation R&D Center, Yongin-si, Gyeonggi-do, Korea.
authors.forename: Hyun
authors.initials: H
authors.lastname: Choi
authors.affiliation: Department of Life Sciences, Ewha Womans University, Seoul, Korea.
authors.forename: Kkot-Nara
authors.initials: KN
authors.lastname: Park
authors.affiliation: Bioscience Research Institute, Amorepacific Corporation R&D Center, Yongin-si, Gyeonggi-do, Korea.
authors.forename: Ju-Yearl
authors.initials: JY
authors.lastname: Park
authors.affiliation: Bioscience Research Institute, Amorepacific Corporation R&D Center, Yongin-si, Gyeonggi-do, Korea.
authors.forename: Tae Ryong
authors.initials: TR
authors.lastname: Lee
authors.affiliation: Bioscience Research Institute, Amorepacific Corporation R&D Center, Yongin-si, Gyeonggi-do, Korea.
authors.forename: Dong Wook
authors.initials: DW
authors.lastname: Shin
authors.affiliation: Department of Life Sciences, Ewha Womans University, Seoul, Korea.
authors.forename: Yun Soo
authors.initials: YS
authors.lastname: Bae
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D054418:Chemokine CCL20 / Q000096:biosynthesis; D016207:Cytokines / Q000096:biosynthesis*; D040002:Dermatophagoides pteronyssinus / Q000276:immunology* / Q000472:pathogenicity*; D000074623:Dual Oxidases; D004789:Enzyme Activation; D055785:Gene Knockdown Techniques; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism*; D016209:Interleukin-8 / Q000096:biosynthesis; D015603:Keratinocytes / Q000276:immunology* / Q000378:metabolism*; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction; D051195:Toll-Like Receptor 2; D051996:Transcription Factor RelA / Q000378:metabolism
chemical_list: C108355:CCL20 protein, human; C508606:CXCL8 protein, human; D054418:Chemokine CCL20; D016207:Cytokines; D018836:Inflammation Mediators; D016209:Interleukin-8; C498143:RELA protein, human; D017382:Reactive Oxygen Species; C495342:TLR2 protein, human; D051195:Toll-Like Receptor 2; D051996:Transcription Factor RelA; D000074623:Dual Oxidases; D019255:NADPH Oxidases; C431515:DUOX2 protein, human
keywords: Toll-like receptors; dual oxidase 2; house dust mite; nuclear factor-κB; reactive oxygen species