The levels of mitochondria and cellular ROS were determined by flow cytometer using CMH2XRos (#M7513) and CM-H2DCF-DA (#C6827) as fluorescent probes (BD Biosciences, San Jose, CA), respectively, as described in previous publications (10 (link),14 (link)). The intracellular levels of GSH/oxidized glutathione (GSSG) and NADPH/NADP+ were measured with a GSH/GSSG Assay kit (#V6612) and a NADPH/NADP+ Assay kit (#G9081) (Promega, WI) according to the manufacturer’s instructions.