Direct repression of IGF2 is implicated in the anti-angiogenic function of microRNA-210 in human retinal endothelial cells.

Pathological angiogenesis leads to the development of retinal vasculopathies and causes severe vision impairment. Increased understanding of the mechanisms underlying the angiogenic behavior of retinal endothelial cells helps provide new insights for developing treatment of retinal vasculopathies. Pro-angiogenic function of miR-210 has previously been identified. However, the functional implication of miR-210 in retinal endothelial cells remains unknown. Human retinal microvascular endothelial cells (HRECs) were employed to investigate the impact of miR-210 on the angiogenic capacity of retinal endothelial cells. It was observed that without affecting the viability of HRECs, miR-210 significantly suppressed the migration and capillary-like tube formation in HRECs. Moreover, pro-angiogenic insulin growth factor 2 (IGF2) was newly identified as a direct target of miR-210 in HRECs. MiR-210 decreased the expression of IGF2 at both mRNA and protein levels in HRECs. IGF2-simulated activation of p38 MAPK was attenuated by miR-210 in HRECs. Recombinant IGF2 protein rescued miR-210-induced impairment of tube formation in HRECs. Therefore, in contrast to the previously reported pro-angiogenic function of miR-210, the current work reveals novel anti-angiogenic activity of miR-210 in HRECs. Furthermore, IGF2 is identified for the first time as a direct target of miR-210 in HRECs, adding new mechanistic insights into the expression regulation of pro-angiogenic IGF2 in human retinal endothelial cells. The current work helps increase the understanding of regulatory mechanisms underlying retinal endothelial cell physiology, justifying further evaluation for the therapeutic implications of miR-210/IGF2 interaction in the treatment of related retinal vasculopathies.