PTEN and ischemia: miR-21 knockdown intensified ischemia-induced renal epithelial cell injury by (1) enhanced apoptosis through the phosphatase and tensin homolog (PTEN)/Akt/mammalian target of rapamycin (mTOR)/hypoxia-inducible factor (HIF) pathways and (2) increased inflammation by promoting dendritic cell maturation.10