Ying Wang1, Ni Tang1, Manyun Mao1, Youyou Zhou1, Yingfang Wu1, Juan Li1, Wei Zhang2, Cong Peng1, Xiang Chen1, Jie Li3. 1. Department of Dermatology, Xiangya Hospital, Central South University, Changsha, China; Hunan Key Laboratory of Skin Cancer and Psoriasis, Xiangya Hospital, Central South University, Changsha, China; Hunan Engineering Research Center of Skin Health and Disease, Changsha, China. 2. Institute of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha, China. 3. Department of Dermatology, Xiangya Hospital, Central South University, Changsha, China; Hunan Key Laboratory of Skin Cancer and Psoriasis, Xiangya Hospital, Central South University, Changsha, China; Hunan Engineering Research Center of Skin Health and Disease, Changsha, China. Electronic address: xylijie@csu.edu.cn.
Abstract
BACKGROUND: Mast cells play an important role in allergic responses and persistently exposure to environmental fine particulate matter (PM2.5) exacerbates allergic diseases,but the details remained elucidative. OBJECTIVES: To investigate the effect of PM2.5 on IgE-mediated mast cell responses through an IgE-mediated mouse model and mast cell activation. METHODS: The β-hexosaminidase release and a BALB/c model of passive cutaneous anaphylaxis (PCA) was used to test IgE-mediated mast cells activation in vitro and in vivo. RNA-Seq technique was conducted to study the gene expression profile. Reactive oxygen species (ROS) production was measured by flow-cytometry. RT-PCR,WB and ELISA were performed to examine targeting molecules expression. RESULTS: PM2.5 facilitated IgE-mediated degranulation and increased cytokines expression in mast cells. Meanwhile, the Evan's blue extravasation as well as serum cytokines in mice was increased after treatment with PM2.5. Furthermore, PM2.5 treatment dramatically increased the expression of Gadd45b which is an oxidative stress molecule that directly activates down-stream pathway, such as MEKK4/JNK. PM2.5 treatment activated MEKK4, JNK1/2 but not ERK1/2 and p38. Meanwhile, Knockdown of Gadd45b significantly attenuated PM2.5-mediated JNK1/2 activation and expression of cytokines. In addition, a JNK1/2-specific inhibitor SP600125 blocked IgE-mediated mast cell activation and cytokine release in PCA model mice. Moreover, PM2.5 treatment increased the ROS level and ROS inhibitor dramatically blocked the PM2.5-induced ROS production and reversed the PM2.5-mediated gene expression in the mitochondrial respiratory chain. CONCLUSIONS: PM2.5 regulates ROS production through Gadd45b/MEKK4/JNK pathway, facilitating IgE-mediated mast cell activation.
BACKGROUND: Mast cells play an important role in allergic responses and persistently exposure to environmental fine particulate matter (PM2.5) exacerbates allergic diseases,but the details remained elucidative. OBJECTIVES: To investigate the effect of PM2.5 on IgE-mediated mast cell responses through an IgE-mediated mouse model and mast cell activation. METHODS: The β-hexosaminidase release and a BALB/c model of passive cutaneous anaphylaxis (PCA) was used to test IgE-mediated mast cells activation in vitro and in vivo. RNA-Seq technique was conducted to study the gene expression profile. Reactive oxygen species (ROS) production was measured by flow-cytometry. RT-PCR,WB and ELISA were performed to examine targeting molecules expression. RESULTS: PM2.5 facilitated IgE-mediated degranulation and increased cytokines expression in mast cells. Meanwhile, the Evan's blue extravasation as well as serum cytokines in mice was increased after treatment with PM2.5. Furthermore, PM2.5 treatment dramatically increased the expression of Gadd45b which is an oxidative stress molecule that directly activates down-stream pathway, such as MEKK4/JNK. PM2.5 treatment activated MEKK4, JNK1/2 but not ERK1/2 and p38. Meanwhile, Knockdown of Gadd45b significantly attenuated PM2.5-mediated JNK1/2 activation and expression of cytokines. In addition, a JNK1/2-specific inhibitor SP600125 blocked IgE-mediated mast cell activation and cytokine release in PCA model mice. Moreover, PM2.5 treatment increased the ROS level and ROS inhibitor dramatically blocked the PM2.5-induced ROS production and reversed the PM2.5-mediated gene expression in the mitochondrial respiratory chain. CONCLUSIONS: PM2.5 regulates ROS production through Gadd45b/MEKK4/JNK pathway, facilitating IgE-mediated mast cell activation.