Resveratrol preconditioning protects against cerebral ischemic injury via Nrf2

Background and Purpose—Nuclear erythroid 2 related factor 2 (Nrf2) is an astrocyteenriched transcription factor that has previously been shown to upregulate cellular antioxidant systems in response to ischemia. While resveratrol preconditioning (RPC) has emerged as a potential neuroprotective therapy, the involvement of Nrf2 in RPC-induced neuroprotection and mitochondrial reactive oxygen species (ROS) production following cerebral ischemia remains unclear. The goal of our study was to study the contribution of Nrf2 to RPC and its effects on mitochondrial function. Methods—We used rodent astrocyte cultures and an in vivo stroke model with RPC. An Nrf2 DNA-binding ELISA and protein analysis via Western blotting of downstream Nrf2 targets were performed to determine RPC-induced activation of Nrf2 in rat and mouse astrocytes. Following RPC, mitochondrial function was determined by measuring ROS production and mitochondrial respiration in both wild-type (WT) and Nrf2−/− mice. Infarct volume was measured to determine neuroprotection, while protein levels were measured by immunoblotting. Results—We report that Nrf2 is activated by RPC in rodent astrocyte cultures, and that loss of Nrf2 reduced RPC-mediated neuroprotection in a mouse model of focal cerebral ischemia. In addition, we observed that wild-type and Nrf2−/− cortical mitochondria exhibited increased uncoupling and ROS production following RPC treatments, Finally, Nrf2−/− astrocytes exhibited decreased mitochondrial antioxidant expression and were unable to upregulate cellular antioxidants following RPC treatment. Conclusion—Nrf2 contributes to RPC-induced neuroprotection through maintaining mitochondrial coupling and antioxidant protein expression. Corresponding Author: Miguel A. Perez-Pinzon, Ph.D., Department of Neurology, D4-5, University of Miami Miller School of Medicine, PO Box 016960, Miami, FL 33101, USA, Phone: (305) 243-6955, Fax: (305)243-5830, [email protected]. HHS Public Access Author manuscript Stroke. Author manuscript; available in PMC 2016 June 01. Published in final edited form as: Stroke. 2015 June ; 46(6): 1626–1632. doi:10.1161/STROKEAHA.115.008921. A uhor M anscript