Qiuli Fu1, Danni Lyu1, Lifang Zhang1, Zhenwei Qin1, Qiaomei Tang1, Houfa Yin1, Xiaoming Lou2, Zhijian Chen3, Ke Yao4. 1. Eye Center of the 2nd Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, China; Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou, Zhejiang Province, China. 2. Department of Environmental and Occupational Health, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang Province, China. 3. Department of Environmental and Occupational Health, Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou, Zhejiang Province, China. Electronic address: zhjchen@cdc.zj.cn. 4. Eye Center of the 2nd Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, China; Zhejiang Provincial Key Lab of Ophthalmology, Hangzhou, Zhejiang Province, China. Electronic address: xlren@zju.edu.cn.
Abstract
PURPOSE: To investigate particulate matter (PM2.5)-induced damage to human corneal epithelial cells (HCECs) and to determine the underlying mechanisms. METHODS: HCECs were exposed to PM2.5 at a series of concentrations for various periods. Cell viability was measured by using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell proliferation was evaluated via 5-ethynyl-2'-deoxyuridine (EdU) analysis, while autophagy was determined by immunofluorescence and Western blot. RESULTS: PM2.5-induced cell damage of HCECs occurred in a time- and dose-dependent manner. Decreased cell viability and proliferation as well as increased apoptosis were observed in HCECs after PM2.5 exposure for 24 h. Autophagy in HCECs was slightly inhibited in the early stage (before 4 h) of exposure but significantly activated in the late stage (after 24 h), as evidenced by a decrease in the former and increase in the latter of the expression of the autophagy-associated markers LC3B, ATG5, and BECN1. Interestingly, rapamycin, an autophagy activator, attenuated early-stage but aggravated late-stage PM2.5-induced cell damage, suggesting that the role of autophagy in HCECs may change over time during PM2.5 exposure. In addition, in the early stage, the expression of LC3B and ATG5 increased in cells co-treated with rapamycin and PM2.5 compared to rapamycin-only or PM2.5-only treated cells, suggesting that autophagy may benefit cell viability after PM2.5 exposure. CONCLUSIONS: The results indicate the potential role of autophagy in the treatment of PM2.5-induced ocular corneal diseases and provide direct evidence for the cytotoxicity, possibly involving an autophagic process, of PM2.5 in HCECs.
PURPOSE: To investigate particulate matter (PM2.5)-induced damage to human corneal epithelial cells (HCECs) and to determine the underlying mechanisms. METHODS: HCECs were exposed to PM2.5 at a series of concentrations for various periods. Cell viability was measured by using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell proliferation was evaluated via 5-ethynyl-2'-deoxyuridine (EdU) analysis, while autophagy was determined by immunofluorescence and Western blot. RESULTS: PM2.5-induced cell damage of HCECs occurred in a time- and dose-dependent manner. Decreased cell viability and proliferation as well as increased apoptosis were observed in HCECs after PM2.5 exposure for 24 h. Autophagy in HCECs was slightly inhibited in the early stage (before 4 h) of exposure but significantly activated in the late stage (after 24 h), as evidenced by a decrease in the former and increase in the latter of the expression of the autophagy-associated markers LC3B, ATG5, and BECN1. Interestingly, rapamycin, an autophagy activator, attenuated early-stage but aggravated late-stage PM2.5-induced cell damage, suggesting that the role of autophagy in HCECs may change over time during PM2.5 exposure. In addition, in the early stage, the expression of LC3B and ATG5 increased in cells co-treated with rapamycin and PM2.5 compared to rapamycin-only or PM2.5-only treated cells, suggesting that autophagy may benefit cell viability after PM2.5 exposure. CONCLUSIONS: The results indicate the potential role of autophagy in the treatment of PM2.5-induced ocular corneal diseases and provide direct evidence for the cytotoxicity, possibly involving an autophagic process, of PM2.5 in HCECs.
Authors: Tae Gu Lee; Soo-Wang Hyun; Kyuhyung Jo; Bongkyun Park; Ik Soo Lee; Su Jeong Song; Chan-Sik Kim Journal: Int J Environ Res Public Health Date: 2019-09-04 Impact factor: 3.390