Biotoxic effects and gene expression regulation of urban PM 2.5 in southwestern China.

Atmospheric fine particulate matter (PM _2.5 ) causes severe haze in China and is regarded as a threat to human health. The health effects of PM _2.5 vary location by location due to the variation in size distribution, chemical composition, and sources. In this study, the cytotoxicity effect, oxidative stress, and gene expression regulation of PM _2.5 in Chengdu and Chongqing, two typical urban areas in southern China, were evaluated. Urban PM _2.5 in summer and winter significantly inhibited cell viability and increased reactive oxygen species (ROS) levels in A549 cells. Notably, PM _2.5 in winter exhibited higher cytotoxicity and ROS level than summer. Moreover, in this study, PM _2.5 commonly induced cancer-related gene expression such as cell adhesion molecule 1 (PECAM1), interleukin 24 (IL24), and cytochrome P450 (CYP1A1); meanwhile, PM _2.5 commonly acted on cancer-related biological functions such as cell-substrate junction, cell-cell junction, and focal adhesion. In particular, PM _2.5 in Chengdu in summer had the highest carcinogenic potential among PM _2.5 at the two sites in summer and winter. Importantly, cancer-related genes were uniquely targeted by PM _2.5 , such as epithelial splicing regulatory protein 1 (ESRP1) and membrane-associated ring-CH-type finger 1 (1-Mar) by Chengdu summer PM _2.5 ; collagen type IX alpha 3 chain (COL9A3) by Chengdu winter PM _2.5 ; SH2 domain-containing 1B (SH2D1B) by Chongqing summer PM _2.5 ; and interleukin 1 receptor-like 1 (IL1RL1) and zinc finger protein 42 (ZNF423) by Chongqing winter PM _2.5 . Meanwhile, important cancer-related biological functions were specially induced by PM _2.5 , such as cell cycle checkpoint by Chengdu summer PM _2.5 ; macromolecule methylation by Chengdu winter PM _2.5 ; endoplasmic reticulum-Golgi intermediate compartment membrane by Chongqing summer PM _2.5 ; and cellular lipid catabolic process by Chongqing winter PM _2.5 . Conclusively, in the typical urban areas of southern China, both summer and winter PM _2.5 illustrated significant gene regulation effects. This study contributes to evaluating the adverse health effects of PM _2.5 in southern China and providing public health suggestions for policymakers.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2020. Published by Elsevier B.V.)