Abstract 15771: Mitochondria Targeted Antioxidant Prevents Mitochondrial Dysfunction Induced by Cardiolipin Deficiency
Cardiolipin, a mitochondrial inner membrane phospholipid, is essential for optimal mitochondrial function. Previous studies have shown that mutation of tafazzin, an acyltransferase for cardiolipin acyl-chain remodeling, reduces the cardiolipin content and causes Barth syndrome, which is a rare X-linked multisystem disorder diagnosed in early infancy. Dilated cardiomyopathy is one of its typical clinic manifestations. Reactive oxygen species (ROS) have been implicated in the development of cardiomyopathy and is also the obligated byproducts of the mitochondrial respiration chain. Based on previous finding that tafazzin knockdown decreases ATP production from mitochondria, we hypothesized that cardiolipin deficiency induced by tafazzin knockdown increases ROS production from mitochondria and mitochondria-targeted antioxidant that prevents cardiolipin deficiency induced mitochondrial dysfunction. We employed rat neonatal ventricular myocyte (NVM) induced by tafazzin knockdown with adenovirus containing tafazzin shRNA as cardiolipin deficiency model to investigate the effects of mitochondrial antioxidant, mito-TEMPO, on the production of ROS and ATP from mitochondria. Knocking down of tafazzin was confirmed by both real-time RT-PCR and Western blot. Mass spectrometry-based shotgun lipidomics analysis showed that tafazzin knockdown decreases the steady state levels of cardiolipin by 13% (n =4, p < 0.01). Tafazzin knockdown increased cellular ROS to 142% compared with NVM treated with scrambled shRNA virus (n = 3, p < 0.05). The treatment of NVM with 25 μM mito-TEMPO totally blocked tafazzin knockdown induced ROS (n = 3, p < 0.01). Mito-TEMPO also abolished tafazzin knockdown induced intracellular ATP decrease (n = 4, p < 0.05) and dramatically decreased the activated (phosphorylated) form of AMP activated protein kinase α. The treatment of NVM with mito-TMPO attenuates tafazzin knockdown induced cytochrome c release as well. In summary, mito-TEMPO prevents cardiolipin deficiency induced mitochondrial dysfunction including enhanced ROS, reduced ATP, and cytochrome c release. Mitochondria-targeted antioxidants may be an effective therapeutic for dilated cardiomyopathies resulted from mitochondrial oxidative stress.
- © 2012 by American Heart Association, Inc.