In vitro Nrf2 reporter assays. Human U937 macrophages were transiently transfected with the Nrf2 luciferase reporter construct and subsequently treated with PFP or t-BHQ (positive control). (A) A dose-dependent increase in Nrf2 activity was observed after PFP treatment. Treatment with 2 μg/cm2 PFP yielded a significant response compared to controls. At 10 μg/cm2, the Nrf2 reporter generated similar levels compared to t-BHQ. (B) PFP treatment increases binding activity of Nrf2 at a consensus ARE binding element using GMSA with ARE consensus oligonucleotide after treatment of U937 macrophages with PFP (2 μg/cm2) and t-BHQ (10 μM) for 90 minutes. (C) HMOX1 mRNA was upregulated approximately 6-fold after 2 μg/cm2 PFP treatment compared to controls. Data are presented as mean+SEM (n=3 separate experiments), * significantly different compared to control.