MiR-1 Is Regulated by Hydrogen Peroxide via MAPK and Limits Cell Migration and Invasion.

MicroRNA-1 (miR-1) is a conserved microRNA that is highly expressed in skeletal and cardiac muscle tissues. Moreover, miR-1 regulates genes and has critical roles in cell migration and invasion. Downregulation of miR-1 has been found in many pathologies of numerous organs, including the lungs. What exactly contributes to the downregulation of miR-1 is not fully understood, and in the present study, we investigated whether ROS regulate miR-1 and its role in cell migration and invasion. A549 cells were grown and maintained in DMEM:F12 (1:1) and supplemented with 10% FBS and 1000 U of Penicillin/Streptomycin and maintained as recommended by the manufacturer (ATCC). Cell migration and invasion, IHC, Western blot, qPCR, ROS, miR-1 transfection, and qPCR were used to determine miR-1 regulation and its role in cell migration. Exogenous miR-1 decreased the formation of ROS and inhibited cell migration and invasion, whereas inhibition of miR-1 increased ROS formation and stimulated cell migration and invasion. Inhibition of miR-1 induced the formation of actin filaments contractile structures, whereas exogenous miR-1 limited the formation of these structures. Hydrogen peroxide significantly decreased miR-1 level, whereas inhibition of Nox4 had no effect on miR-1 level. Alpha amanitin did not decrease miR-1 level, whereas inhibition of NF-кB temporally decreased miR-1 level. This study demonstrates that ROS suppress miR-1 and that miR-1 is posttranscriptionally regulated via MAPK. Endogenous Nox4-dependent ROS are not involved in miR-1 regulation, whereas exogenous ROS regulates miR-1. NF-κB plays a key role in miR-1 regulation in both redox and nonredox environments. Moreover, Mir-1 limits cell migration and invasion even in the presence of ROS. TSP-1 is a major regulator of TGFβ and its expression is upregulated by ROS. Our work indicates ROS is a major regulator of miR-1 and TSP-1 and could be a potential therapeutic target to limit ROS- and non-ROS-mediated processes in lung cells.