Lopimune -Induced Mitochondrial Toxicity is attenuated by increased uncoupling protein - 2 level in treated mouse hepatocyes

The objective of this study is to evaluate mitochondrial respiration, production of reactive oxygen species (ROS) and expression of uncoupling protein-2 (UCP2) in mouse hepatocytes following lopimune administration. Mitochondria were extracted from mouse liver using differential centrifugation and hepatocytes were isolated by collagenase perfusion procedure. Mitochondrial respiration was measured using Rank Brothers oxygen electrode. ROS production in hepatocytes was monitored by flow cytometry using 2′,7′-Dichlorofluorescin diacetate probe and UCP2 protein expression was detected by western blot. We found that lopimune induced a significant decrease of approximately 30% in respiratory control ratio starting from day 4 till day 9 of treatment. This decrease was due to an increase in state 4 respiration, reflecting an increase in mitochondrial proton leak. State 2 and state 3 respirations were not affected. Moreover, ROS production significantly increased by about 2-fold after day 1 of treatment and decreased after day 3, returning to the resting level on day 5. Interestingly, UCP2 which is absent in control hepatocytes, was expressed starting from day 4 of treatment. Our findings indicate that lopimune-induced proton leak, mediated by UCP2, may represent a response to inhibit the production of ROS as a negative feedback regulatory mechanism. These results imply a potential involvement of UCP2 in the regulation of oxidative stress, and add new insights into the u...

Source: BJ Cell - April 13, 2015 Category: Biochemistry Authors: S El Hoss, G M. Bahr, K S. Echtay Tags: BJ Cell Source Type: research