Aryl hydrocarbon receptor orchestrates transcriptomic, non-coding and splicing programs that drive human lung...

Cannabis vaping is increasingly consumed as an alternative to cannabis smoke, yet its health consequences remain poorly defined. Vaporization may reduce the formation of combustion-related toxicants, but emerging data suggest that cannabis vaping still elicits deleterious effects in respiratory epithelial cells. While the actions of cannabis are commonly attributed to cannabinoid receptors, other molecular targets such as the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, may play a role. In this study, we used wild-type (A549^WT) and AhR-knockout (A549^AHRKO) human alveolar epithelial cells cultured at the air-liquid interface (ALI) to investigate whether AhR mediates the response to cannabis vapor. Cells were exposed using the expoCube to achieve THC levels of ~ 2 μg. Under basal conditions, AhR supported cell proliferation and regulated long non-coding RNAs (lncRNA) associated with cell cycle progression. Cannabis vapor exposure increased cell growth in an AhR-dependent manner. Transcriptomic profiling revealed that both protein-coding genes and lncRNA affiliated with cell cycle were upregulated in A549^WT but not in A549^AHRKO cells, indicating AhR is required to promote the transcriptional response to cannabis vapor. The AhR also modulated alternative splicing events in response to cannabis vapor, with increased splicing alterations observed in A549^WT cells compared to A549^AHRKO cells, signifying the AhR coordinates distinct post-transcriptional responses to cannabis vapor exposure. These results suggest a potential link between cannabis vapor exposure and oncogenic signaling, highlighting AhR as a molecular sentinel that shapes epithelial cell response to cannabis vapor through coordinated transcriptional and post-transcriptional regulation.