Damage Effects And Mechanism Of Human Bronchial Epithelial Cells Exposed To Airborne PM_2.5 In Nanjing City

With the development of urbanization and industrialization,the air pollution has become a severe public problem for harming people's health.As one of the major components of air pollution,PM_2.5 attracts lots of attention in recent years.A large number of epidemiological and toxicological studies have demonstrated that PM_2.5 would harm to human health.However,the mechanism of adverse health effects caused by PM_2.5 remain incompletely understood.In order to explore the molecular mechanism underlying PM_2.5-induced cytotoxic effects,we collected the airborne PM_2.5 from the urban area of Nanjing City,and adopted Inductively Coupled Plasma Mass Spectrometry?ICP-MS?and Gas Chromatography-Mass Spectrometer?GC-MS?,and combined in vitro,genome expression profiling microarray,we carried out the following research:?1?analyze the chemical composition of PM_2.5 in Nanjing City.?2?explore the changes in gene expression of human bronchial epithelial cells exposed to PM_2.5 and investigate the potential molecular mechanism.Part I Chemical composition analysis of PM_2.5 in NanjingObjective:PM_2.5 is a severe air pollutant,and the loading component in which is very complex.The PM_2.5 chemical composition depend on many factors,such as the season,place,meteorological and geographical factors and so on.In this study,we collected the airborne PM_2.5 of Nanjing city.Water soluble ion,chemical elements,and polycyclic aromatic hydrocarbons were analyzed.Methods:The sampling site is located in the Hanzhong Road,which is in the urban area of Nanjing city,and the sampling time was from March to May of 2015.The glass fiber filters or quartz filters were used for sampling.Chromatography System was used to analyze water soluble inorganic ions,and the elements were determined by ICP-MS,and the PAHs were analyzed by GC-MS.Results:The daily average PM_2.5 concentration in Nanjing during the sampling period was 94.13±35.42?g/m3.Four anions?SO42-,NO3-,Cl-,F-?and six cations?NH4+,Ca2+,Na+,K+,Mg2+,Li+?were measured.The total mass concentration of anions was higher than cations.SO42-,NO3-and NH4+ were the largest contributors to PM_2.5.Twenty-one elements were detected,and the top four of elements accounting for PM_2.5 were As,P,Sn,Ti,and Pb,Sr and Mo were in the low level.We also determined sixteen PAHs in PM_2.5 samples.The mass concentration of individual compound for PAHs range from 0.10 ng/m3 to 14.10ng/m3,the highest and lowest concentration for individual compound were indeno?1,2,3-CD?pyrene and acenaphthene,respectively.Conclusion:During the sampling period,the daily average PM_2.5 concentration in Nanjing city was higher than the national air quality standard.The water soluble ions accounted for the largest part for PM_2.5.The concentration of As and PAHs were in high levels,and PM_2.5 pollution in Nanjing should be attracted attention.Part? Damage effects and mechanism of HBE cells exposed to airborne PM_2.5Objective:We analyzed the chemical composition of PM_2.5 in Nanjing city in the first part,but the mechanism of adverse health effects caused by PM_2.5 remain incompletely understood.In this part,we preliminarily research the changes in gene expression profiling of HBE cells exposed to PM2.s,and further explore potential molecular mechanism.Methods:The HBE cells were exposed to 150?g/ml PM_2.5 for 48h,and the control group was set up at the same time.We adopted Agilent mRNA single-channel expression profiling microarray to detect the impact of PM_2.5 on gene expression profiling of HBE cells and screened the differentially expressed genes.The Benzopyrene?B?a?P?was set as the positive control.Then we used RT-PCR and Western blot to verify the results of microarray analysis.After exposing to PM_2.5 for 48h at the concentration of 150?g/ml,we detected the changes of EROD,ROS,IL-6 levels,and the impact on JAK/Stat signal pathway.Meanwhile,we observed changes of cytotoxic effects induced by PM_2.5 after a-naphthoflavone?ANF,CYP1A1/1B1 inhibitor?treatment.Results:The results showed that CYP1A1/1B1 were significantly up-regulated after exposure to PM_2.5.Both mRNA expression and protein expression of CYP1A1/1B1 increased significantly after PM_2.5,B?a?P and PM_2.5+B?a?P treatment,respectively,compared with control group.The level of EROD,ROS,IL-6,and cellular apoptosis rate were significantly higher than the control group.PM_2.5 treatment also induced activation of STAT3.CYP1A1/1B1 inhibitor?ANF?strongly reduced PM_2.5-induced expression of EROD,ROS and IL-6.The results also showed the tendency of inhibiting apoptosis and STAT3 activation.Conclusion:PM_2.5 can induce the high expression of CYP1A1/1B1and damage effects on HBE cells,and CYP1A1/1B1 were involved in PM_2.5-induced damage effects.