The CYP1A1/ chimeric RNA RPL17-C18orf32 axis mediates Benzo[ghi]perylene induced-respiratory toxicity and DNA damage in vitro and in vivo

Benzo[ghi]perylene (BghiP), a prevalent high-molecular-weight (HMW) polycyclic aromatic hydrocarbon (PAH) with significant environmental exposure, poses potential health risks that remain inadequately characterized. This study investigated the respiratory toxicity of BghiP exposure and its underlying mechanisms in vitro (human bronchial epithelial cells BEAS-2B and 16HBE) and in vivo (mouse model). Chronic exposure to environmentally relevant concentrations of BghiP (500 ng/mL for 2 weeks in vitro ; 500 µg/m 3 for 4 weeks in vivo ) significantly reduced cell proliferation, induced apoptosis and cell cycle arrest, and caused DNA damage in BEAS-2B and 16HBE cells. In vivo, BghiP exposure increased lung coefficients, induced pathological alterations, and triggered pulmonary inflammation. Mechanistically, BghiP exposure upregulated the expression of cytochrome P450 (CYP1A1), which subsequently promoted the transcription of chimeric RNA RPL17-C18orf32. We identified that the CYP1A1/RPL17-C18orf32 axis plays a pivotal role in mediating BghiP's toxic effects. Knockdown of either CYP1A1 or RPL17-C18orf32 attenuated BghiP-induced cytotoxicity, DNA damage, and cellular dysfunction, while overexpression of RPL17-C18orf32 exacerbated these detrimental effects. Co-manipulation experiments further confirmed that CYP1A1 acts upstream to regulate RPL17-C18orf32 expression. This study is the first to provide evidence that the CYP1A1/RPL17-C18orf32 axis is a critical mediator of BghiP-induced respiratory toxicity and DNA damage. Our findings systematically elucidate the cytotoxic and genotoxic effects of BghiP, introducing the novel concept of chimeric RNA involvement in PAH toxicity mechanisms and offering a new perspective for understanding the health impacts of environmental pollutants.