Particulate matter induces inflammatory cytokine production via activation of NFκB by TLR5-NOX4-ROS signaling in human skin keratinocyte and mouse skin

Publication date: Available online 15 December 2018Source: Redox BiologyAuthor(s): Yea Seong Ryu, Kyoung Ah Kang, Mei Jing Piao, Mee Jung Ahn, Joo Mi Yi, Young-Min Hyun, Seo Hyeong Kim, Min Kyung Ko, Chang Ook Park, Jin Won HyunAbstractParticulate matter (PM) increases levels of pro-inflammatory cytokines, but its effects on the skin remain largely unknown. We investigated the signal transduction pathway and epigenetic regulatory mechanisms underlying cellular inflammation induced by PM with a diameter of ≤ 2.5 (PM2.5) in vitro and in vivo. PM2.5-treated skin keratinocytes produced various inflammatory cytokines, including IL-6. The binding of PM2.5 to TLR5 initiated intracellular signaling through MyD88, and led to the translocation of NFκB to the nucleus, where it bound the NFκB site within IL-6 promoter. Furthermore, PM2.5 induced a direct interaction between TLR5 and NOX4, and in turn induced the production of ROS and activated NFκB-IL-6 downstream, which was prevented by siRNA-mediated knockdown of NOX4 or antioxidant treatment. Furthermore, expression of TLR5, MyD88, NOX4, phospho-NFκB, and IL-6 was increased in skin tissue of PM2.5-treated flaky tail mice. PM2.5-induced increased transcription of IL-6 was regulated via DNA methylation and histone methylation by epigenetic modification; the binding of DNA demethylase and histone methyltransferase to the IL-6 promoter regions resulted in increased IL-6 mRNA expression. Our findings provide deep insight into the pat...
Source: Redox Biology - Category: Biology Source Type: research