MicroRNA-351-5p aggravates intestinal ischaemia/reperfusion injury through the targeting of MAPK13 and Sirtuin-6

Intestinal ischaemia-reperfusion (II/R) injury is a serious clinical problem. Here we have investigated novel mechanisms and new drug targets in II/R injury by searching for microRNAs regulating such injury.

We used hypoxia/reoxygenation (H/R) of IEC-6 cell cultures and models of II/R models in rats and mice. Microarray assays were used to identify target miRNAs from rat intestinal. Real-time PCR, Western blot and dual luciferase reporter assays, and agomir and antagomir in vitro and in vivo were used to assess the effects of the target miRNA on II/R injury.

The miR-351-5p was differentially expressed in our models and it targeted MAPK13 and sirtuin-6. This miRNA reduced levels of sirtuin-6 and AMP-activated protein kinase phosphorylation, and activated forkhead box O3 (FoxO3α) phosphorylation to cause oxidative stress. Also, miR-351-5p markedly reduced MAPK13 level, activated polycystic kidney disease 1/NF-κB signal and increased NF-κB (p65). Moreover, miR-351-5p up-regulated levels of Bcl2-associated X, cytochrome c, apoptotic peptidase activating factor 1, cleaved-caspase 3 and cleaved-caspase 9 by reducing sirtuin-6 levels to promote apoptosis. In addition, miR-351-5p mimic in IEC-6 cells and agomir in mice aggravated these effects, and miR-351-5p inhibitor and antagomir in mice alleviated these actions.

Our data showed that miR-351-5p aggravated II/R injury by promoting intestinal mucosal oxidative stress, inflammation and apoptosis by targeting MAPK13 and sirtuin-6.These data provide new insights into the mechanisms regulating II/R injury, and of miR-351-5p could be considered as a novel therapeutic target for such injury.