Role of Novel Redox Regulator, MnTnBuOE‐2‐PyP 5+ in Rotenone Induced 4‐HNE Aggresosome Degradation through Autophagy in Cardiomyocytes

Abstract

Oxidative stress has been linked to pathogenesis of cardiovascular disease. Mitochondria is the major site where reactive oxygen species (ROS) are produced and mainly generated from complex I and complex III of electron transport chain. ROS leads to generation of reactive aldehydes known as 4-hydroxynonenal (4-HNE) through lipid peroxidation. 4-HNE modifies protein through covalent adduction thereby causing their crosslinking, aggregation, and inactivation. It has been little known about degradation of 4-HNE adducted proteins. Autophagy is a dynamic process which maintains cellular homeostasis by removing damaged organelles and protein. There has been use of antioxidant in cardiovascular disease in order to detoxify ROS and ameliorate disease process. Superoxide dismutase (SOD) mimetic, MnTnBuOE-2-PyP5+ has shown to be promising treatment in oxidative stress induced disease pathology because of its specificity to superoxide (O −), high lipophilicity and less toxic profile. In this study, we are trying to explore the role of, MnTnBuOE-2-PyP5+on rotenone induced 4-HNE aggresosome formation and its degradation process in HL-1 cardiomyocyte. Rotenone, a complex I inhibitor treatment (500nM) for 24 hours increased ROS in HL-1 cardiomyocytes. Rotenone treatment led to increase accumulation 4-HNE aggresosome in HL-1 cardiomyocytes. Rotenone treatment induce increase in LC3-II shown by immunoblotting and immunofluorescence. Pre-treatment with MnTnBuOE-2-PyP5+(20 µM) for 24 hours attenuated rotenone induced ROS formation. In addition, pre-treatment with mimetic decreased 4-HNE aggresosome and LC3-II. Rotenone induced increase in autophagosome was attenuated by pre-treatment with MnTnBuOE-2-PyP5+ as shown by fluorescent-tagged LC3 (tfLC3). Rotenone induced tubulin hyperacetylation through ROS mediated pathway which was attenuated by MnTnBuOE-2-PyP5+. These results indicate that pre-treatment with MnTnBuOE-2-PyP5+ decrease rotenone induced 4-HNE aggresosome by enhancing their degradation process.