Neuregulin-1 inhibits autophagy by activating Akt/ROS signaling pathway to improve doxorubicin induced cardiotoxicity

Objective To explore the role for neuregulin-1(NRG-1) in attenuating doxorubicin(DOX)-induced autophagy and defining the signaling pathways through which it mediates some of its effects. Methods Neonatal rat ventricular mocytes(NRVMs) were separated from two-day-old SD rats. NRVMs were subjected to various treatments in order to both induce autophagy and to determine the effects of NRG-1 on the process. After treated with neuregulin-1(1 μg/ml ), DOX(1 μmol/L), the inhibitor of PI3K LY294002 (10 μmol/L), NAC(50 μmol/L). Activation of autophagy was determined by observing increases in the well-defined markers of autophagy (including protein levels of LC3 and Beclin 1, the formation of GFP-LC3 puncta ). The activation of Akt was detected by means of western blot analysis. Intracellular ROS was determined via fluorescent detection of dihydrodichlorofluorescein (DCF). Results Compared to DOX group, Beclin 1[(3.48±0.84)vs(1.94±0.75), P<0.05]and LC3 Ⅱ[(2.26±0.78)vs(0.94±0.48), P<0.05]protein expression were markedly reduced, as well as the GFP-LC3 positive cells(P<0.05) and the level of ROS production[(174±3.8)vs(114±2.4), P<0.05]was significantly reduced in NRG-1+ DOX group. Effects that were similar with the cells which were treated with the antioxidant NAC+ DOX. Compared to NRG-1+ DOX group, these effects were blocked by the PI3K inhibitor LY294002, which increased the protein expression of Beclin 1[(1.26±0.71)vs(4.63±0.72), P<0.05], LC3Ⅱ[(1.96±0.57)vs(5.02±0.81), P<0.05]and the level of ROS production[(102±4.5)vs(157±4.9), P<0.05]. Pointing to the involvement of the Akt pathway in mediating the process. Conclusion NRG-1 is a potent inhibitor of DOX-induced autophagy and multiple signaling pathways, including Akt and activation of ROS, play important roles in the anti-autophagy effect. NRG-1 is a novel drug that may be effectively therapeutically in protecting further damage in DOX-induced damaged myocardium. Key words: Cardiotoxins; Neuregulin-1; Doxorubicin; Autophagy