Nucleotide Excision Repair Pathway Activity Is Inhibited by Airborne Particulate Matter (PM10) through XPA Deregulation in Lung Epithelial Cells.

Ericka Marel Quezada-Maldonado,Rocío Morales-Bárcenas,Yolanda I. Chirino,Yesennia Sánchez-Pérez,María Eugenia Gonsebatt,Claudia M. García-Cuellar

doi:10.3390/ijms23042224

Abstract

Airborne particulate matter with a diameter size of ≤10 µm (PM10) is a carcinogen that contains polycyclic aromatic hydrocarbons (PAH), which form PAH–DNA adducts. However, the way in which these adducts are managed by DNA repair pathways in cells exposed to PM10 has been partially described. We evaluated the effect of PM10 on nucleotide excision repair (NER) activity and on the levels of different proteins of this pathway that eliminate bulky DNA adducts. Our results showed that human lung epithelial cells (A549) exposed to 10 µg/cm2 of PM10 exhibited PAH–DNA adducts as well as an increase in RAD23 and XPD protein levels (first responders in NER). In addition, PM10 increased the levels of H4K20me2, a recruitment signal for XPA. However, we observed a decrease in total and phosphorylated XPA (Ser196) and an increase in phosphatase WIP1, aside from the absence of XPA–RPA complex, which participates in DNA-damage removal. Additionally, an NER activity assay demonstrated inhibition of the NER functionality in cells exposed to PM10, indicating that XPA alterations led to deficiencies in DNA repair. These results demonstrate that PM10 exposure induces an accumulation of DNA damage that is associated with NER inhibition, highlighting the role of PM10 as an important contributor to lung cancer.

Highlights

Introduction iationsOutdoor air pollution, particulate matter (PM), has an impact on the incidence and mortality of lung cancer worldwide [1,2]
The aim of this study was to investigate the deregulation of the RAD23, XPD, XPA, pXPAs196, H4k20me2, and WIP1 proteins, which are the main components of nucleotide excision repair (NER) pathway responsible for the removal of bulky DNA damage, establishing an association with the NER pathway activity in A549 lung epithelial cells exposed to PM10 for 24 and 48 h
PM10 exposure for 24 h increased the levels of BPDE–DNA adducts in A549 cells compared with the control group (FC = 2.01 vs. 0.0; p < 0.05) (Figure 1)