PYDDT, a novel phase 2 enzymes inducer, activates Keap1–Nrf2 pathway via depleting the cellular level of glutathione

Keap1–Nrf2 pathway has emerged as a regulator for the endogenous antioxidant response, which is critical in defending cells against carcinogenesis. Herein, we demonstrated that depleting the cellular level of glutathione (GSH) by a novel electrophilic agent 2-(pro-1-ynyl)-5-(5,6-dihydroxypenta-1,3-diynyl) thiophene (PYDDT) could activate Keap1–Nrf2 pathway. In above process, it was found that Keap1 was modified by S-glutathionylation, an important post-translational modification of protein cysteines with critical roles in oxidative stress and signal transduction. We concluded from our findings that conjugation with intracellular GSH by PYDDT might lead to Keap1 S-glutathionylation and was a key event involved in its Nrf2 inducing activity.