PM2.5 Induces Cardiomyoblast Senescence via AhR-Mediated Oxidative Stress.

Previous research has established a correlation between PM2.5 exposure and aging-related cardiovascular diseases, primarily in blood vessels. However, the impact of PM2.5 on cardiomyocyte aging remains unclear. In this study, we observed that extractable organic matter (EOM) from PM2.5 exposure led to cellular senescence in H9c2 cardiomyoblast cells, as characterized by an increase in the percentage of β-galactosidase-positive cells, elevated expression levels of p16 and p21, and enhanced H3K9me3 foci. EOM also induced cell cycle arrest at the G1/S stage, accompanied by downregulation of CDK4 and Cyclin D1. Furthermore, EOM exposure led to a significant elevation in intracellular reactive oxygen species (ROS), mitochondrial ROS, and DNA damage. Supplementation with the antioxidant NAC effectively attenuated EOM-induced cardiac senescence. Our findings also revealed that exposure to EOM activated the aryl hydrocarbon receptor (AhR) signaling pathway, as evidenced by AhR translocation to the nucleus and upregulation of Cyp1a1 and Cyp1b1. Importantly, the AhR antagonist CH223191 effectively mitigated EOM-induced oxidative stress and cellular senescence. In conclusion, our results indicate that PM2.5-induced AhR activation leads to oxidative stress, DNA damage, and cell cycle arrest, leading to cardiac senescence. Targeting the AhR/ROS axis might be a promising therapeutic strategy for combating PM2.5-induced cardiac aging.