Fluorescent Nanocomposite for Visualizing Cross-Talk between MicroRNA-21 and Hydrogen Peroxide in Ischemia-Reperfusion Injury in Live Cells and In Vivo.

MicroRNAs (miRNAs) and reactive oxygen species (ROS) are concurrently implicated in heart ischemia-reperfusion (IR) injury. There may exist mutual cross-talk between miRNAs and ROS in cardiac IR injury process. In this study, we developed a novel crown-like silica@polydopamine-DNA-CeO2 nanocomposite by assembly of silica@polydopamine-DNA1 nanoparticles decorated with satellite CeO2 -DNA2 nanoparticles for detecting and imaging of microRNA-21 (miR-21) and hydrogen peroxide (H2 O2 ) in simulated IR injury in living cells and in vivo. The miRNA-21 was found to be regulated by H2 O2 via PI3K/AKT signaling pathway for the first time in H9C2 cells in simulated ischemia-reperfusion injury. H2 O2 and miRNA-21 are overproduced during mimicked heart ischemia-reperfusion injury, suggesting that they are closely related to reperfusion injury. All these results reveal that there is definite cross-talk between miR-21 and H2 O2 in IR injury. The current method can provide a promising strategy to further explore the interplaying roles between ROS and miRNAs in other pathological processes.