miR-17-5p attenuates kidney ischemia-reperfusion injury by inhibiting the PTEN and BIM pathways

BACKGROUND: Kidney ischemia-reperfusion (I/R) injury is an independent risk factor for delayed graft function after kidney transplantation with long-term graft survival deterioration. Previously, we found that the upregulated expression of miR-17-5p exerts a protective effect in kidney I/R injury, but the mechanism has not been clearly studied. METHODS: A kidney I/R injury model was induced in adult C57BL/6 male mice (20–22 g) by clamping both kidney pedicles for 30 min. The miR-17-5p agomir complex was injected into mice 24 h before surgery via the tail vein at a total injection volume of 10 µL/g body weight. The mice were euthanized on post-I/R injury day 2, and kidney function, apoptosis, autophagy, and related molecules were then detected. Human kidney-2 (HK-2) cells, which underwent hypoxia/reoxygenation, were treated with the miR-17-5p agomir, miR-17-5p antagomir, and small interfering ribonucleic acids (siRNAs). Cell viability, apoptosis, autophagy, and molecules were also examined. RESULTS: Autophagy, miR-17-5p expression, and kidney function damage were significantly more increased in the I/R group than in the sham group. In the cultured HK-2 cells underwent hypoxia/reoxygenation, the miR-17-5p agomir directly inhibited the expression of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and Bcl-2 like protein 11 (BIM), and attenuated apoptosis and autophagy. Further, miR-17-5p inhibited autophagy by activating the protein kinase B (Akt)/Beclin1 pathway, which was suppressed by siRNAs. Additionally, the administration of miR-17-5p agomir greatly improved kidney function in the I/R mice group by inhibiting autophagy and apoptosis. CONCLUSIONS: These findings suggest a new possible therapeutic strategy for the prevention and treatment of kidney I/R injury. The upregulation of miR-17-5p expression appears to inhibit apoptosis and autophagy by suppressing PTEN and BIM expression, which in turn upregulates downstream Akt/Beclin1 expression.