Nrf2 Responses in a 3D Human Airway Model Exposed to Whole Aerosol from Combustible Cigarettes or Heated Tobacco Products

April 3, 2023

SOT 62nd Annual Meeting and ToxExpo, March 19-23 2023, Nashville, Tennessee, USA

Brian M. Keyser1, John Wertman1, Michael Hollings2, Kristen Jordan1

1 Scientific & Regulatory Affairs, RAI Services Company, Winston-Salem, NC;
2 Labcorp Early Development Laboratories Ltd., Harrogate, UK

The nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway, activated in human lung cells by cigarette smoke, regulates genes involved in the antioxidative stress response. Here, we evaluated whole smoke/aerosol from two marketed combustible cigarettes (CC), 1R6F reference cigarette, four HTP (glo™) styles, and a marketed HTP comparator on cell viability and Nrf2 response in a 3D human airway model (EpiAirway™) transfected with a luciferase Nrf2 promoter. EpiAirway™ tissues were exposed at the air liquid interface to whole smoke or aerosol. Eighteen hours post-exposure, luciferase activity and cell viability were measured. Relative luciferase activity was expressed as fold change over the air exposed control. Post-exposure, whole smoke/aerosol deposition was quantified using chemical analysis (e.g., glycerol, nicotine, carbonyls). Differential Nrf2 activation was observed following exposure to CC whole smoke compared to the glo™ and the marketed comparator HTP aerosols. Moreover, the minimum exposurecorrelated nicotine concentration required to induce a >2-fold increase (threshold response) in Nrf2 activation was >30x lower for CC than the HTPs. These data show that the 3D Nrf2 EpiAirway™ in vitro model can be used to assess and discriminate responses for a biomarker (oxidative stress) from disease pathways associated with smoking (e.g., respiratory and cardiovascular disease).

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