Downregulation of miRNA-184 Promotes Nerve-Associated Angiogenesis via Vascular Endothelial Growth Factor A Following Ischemic Stroke.

PURPOSE: The implication of several microRNAs in ischemic stroke and preclinical studies suggests that targeting these microRNAs could aid stroke recovery. MicroRNA-184 (miR-184) is downregulated in ischemic stroke in rats, and its downregulation contributes to corneal neovascularization. However, it is not clear whether miR-184 plays a part in angiogenesis following brain ischemia-reperfusion. We sought to determine if miR-184 participates in angiogenesis in response to ischemic stroke with the aim of identifying a targetable pathway to facilitate recovery after stroke.

PATIENTS AND

METHODS

In this study, we investigated the effect of miR-184 on nerve-associated angiogenesis following brain ischemia-reperfusion by analyzing miR-184 expression levels in the peripheral blood of 10 healthy individuals and 15 individuals with ischemic stroke, a rat middle cerebral artery occlusion model, and human SH-SY5Y neuroblastoma cells co-cultured with human umbilical vein endothelial cells and subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) to model interactions between neurons and brain endothelial cells. We used luciferase reporter assays to evaluate downstream target expression and microscopy to observe nerve-associated angiogenesis.

RESULTS

We found that miR-184 expression was significantly downregulated in patients with ischemic stroke, rats subjected to middle cerebral artery occlusion, and human SH-SY5Y cells after OGD/R. Inhibition of miR-184 expression markedly promoted angiogenesis in vitro, as evidenced by increased numbers of vascular nodes, meshes and segments, and elevated vascular endothelial growth factor A expression. Luciferase reporter assays verified type 2 phosphatidic acid phosphatase B (PPAP2B) mRNA as a direct downstream target of miR-184. Moreover, deletion of PPAP2B markedly reduced miR-184-associated angiogenesis.

CONCLUSION

miR-184 is notably downregulated in brain tissue and cells in response to ischemia-reperfusion, thereby contributing to nerve-associated angiogenesis in vitro by enabling greater expression of PPAP2B and vascular endothelial growth factor A. These findings may aid the development of interventions for stroke recovery.