miRNA-181a Over Expression Acts as Potent Anti-Oxidant by Increasing SOD-1 and Nrf-2 in Hepatic Cells

Background and Aims: Oxidative stress plays an important role in inducing apoptosis and injury in hepatocytes. In response to the injury, the cells proliferate and replace the injured cells. There is a difference in the protein expression during liver injury, which is tightly regulated by several mechanisms. One of the mechanisms could be through miRNAs. In this study, we hypothesized thatmiRNA-181a could induce nrf-2, thereby acting as a potent anti-oxidant in decreasing the amount of ROS generated in hepatic cells. Methods: Chang liver cell line was used for all the experiments. miRNA-181a was over expressed in these cells using siPORT NeoFX transfection reagent as per the manufacturer’s instructions. The cells were collected after 72 h of transfection. The cells were collected for either protein or RNA isolation. Total RNA was isolated, cDNA was synthesized and the real time RT-PCR was performed for superoxide dismutase-1 (SOD-1), SOD-2 and glutathione peroxidase-1. Western Blots were performed for erk1/2, nrf2 and b-actin. Results: miRNA-181a over expression resulted in a significant increase in the SOD-1 levels (5-fold increase compared to control). There was no significant change in SOD-2 and Gpx-1. Western Blot analysis revealed that over-expressing miRNA-181a also upregulated the protein levels of Nrf2 (2-fold as compared to control) and erk1/2. Conclusion: The data from this study showed that the over expression of miRNA-181a in non-cancerous hepatic cells increased the SOD-1 levels and nrf-2 levels, which could play a role in decreasing ROS levels in hepatic injury.