MicroRNA1 modulates oxLDL-induced hyperlipidemia by down-regulating MLCK and ERK/p38 MAPK pathway

This study was aimed to determine whether microRNA1 (miR1) plays a role in the activation of myosin light chain kinase (MLCK) mediated by oxLDL in human umbilical vein endothelial cells (HUVECs).

HUVECs were treated with oxLDL along with a control miR or miR1 mimic. MiR1 expression was assayed by miRNA plate assay kit and mirVana™ miRNA isolation kit. The MLCK protein, transcript, and kinase activity were measured by Western blot, real-time-polymerase chain reaction and γ-(32)P-ATP phosphate incorporation, respectively. In addition, phosphorylation of MLC, ERK and p38 was analyzed by Western blot.

The results showed that upon treatment with oxLDL, miR1 expression was decreased, whereas MLCK expression was increased, in a time- and dose-dependent manner. Consistent with this, miR1 mimic prevented MLCK expression and activation and attenuated the phosphorylation of MLC and ERK/p38 in oxLDL-treated HUVECs. Furthermore, we showed that miR1 was able to bind a site located at the 3'un-translational region of MLCK mRNA and inhibited its expression.

Taken together, this study demonstrated that the effect of miR1 on hyperlipidemia is mediated through down-regulation of MLCK and the ERK/p38 MAPK pathway.