Upregulation of MicroRNA-210 Regulates Renal Angiogenesis Mediated by Activation of VEGF Signaling Pathway under Ischemia/Perfusion Injury in vivo and in vitro

Background: MicroRNAs (miRNAs) are endogenous, non-coding, small RNAs that regulate gene expression and function, but little is known about regulation of miRNAs in the kidneys under normal or pathologic conditions. Here, we sought to investigate the potential involvement of miRNAs in renal ischemia/reperfusion (I/R) injury and angiogenesis and to define some of the miRNAs possibly associated with renal angiogenesis. Methods and Results: Male Balb/c mice were subjected to a standard renal I/R. CD31 immunostaining indicated a significant increase of microvessels in the ischemic region. VEGF and VEGFR2 expression were increased in renal I/R at both the mRNA and protein levels which were detected by qRT-PCR and Western blot, respectively. More importantly, 76 microRNAs exhibited more than 2-fold changes using Agilent microRNA microarray, which contains downregulation of 40 miRNAs and upregulation of 36 miRNAs. Upregulation of miR-210 was confirmed by qRT-PCR with prominent changes at 4 and 24 h after reperfusion. Furthermore, overexpression of miR-210 in HUVEC-12 cells enhances VEGF and VEGFR2 expression and promotes angiogenesis on Matrigel in vitro. Conclusion: These findings suggest miR-210 may be involved in targeting the VEGF signaling pathway to regulate angiogenesis after renal I/R injury, which provides novel insights into the angiogenesis mechanism of renal I/R injury.