CircRNA MALAT1/miR-96-5p/FOXK2 axis regulates choroidal neovascularization

Objective  This study determined the role of circRNA MALAT1 (circ-MALAT1) in Choroidal Neovascularization (CNV).

Methods  CNV mice were induced by laser photocoagulation, and Hypoxic human Retinal Microvascular Endothelial Cells (HRMECs) were induced using cobalt chloride. circ-MALAT1 expression pattern was determined in CNV mice and hypoxic HRMECs. Hematoxylin-eosin staining and fluorescein fundus angiography were performed to examine focal areas in CNV mice. Endothelial cell proliferation and migration assay, tubule formation assay, and apoptosis assay were conducted to determine angiogenesis in vitro. Circ-MALAT1-mediated CNV development was investigated using bioinformatics, luciferase analysis, and RNA immunoprecipitation.

Results  circ-MALAT1 expression was upregulated in laser-induced CNV mice and hypoxic HRMECs. circ-MALAT1 silencing delayed structural disorganization of choroidal membranes and the formation of CNV, which was abolished by miR-96-5p inhibitors. circ-MALAT1 silencing decreased HRMEC viability, proliferation, migration, and tube formation and promoted apoptosis. circ-MALAT1 acted as a miR-96-5p sponge, chelating and inhibiting miR-96-5p activity, which led to increased expression of FOXK2. miR-96-5p overexpression mimicked the anti-angiogenic effects mediated by circ-MALAT1 silencing. FOXK2 overexpression diminished circ-MALAT1 silencing-mediated inhibition of endothelial cell progression. Furthermore, significant upregulation of circ-MALAT1 and FOXK2 expression was detected in clinical samples from neovascular age-related macular degeneration patients.

Conclusion  The introduction of circ-MALAT1/miR-96-5p/FOXK2 as a potential therapeutic target in this study provides new insights into the molecular pathogenesis of CNV, but our preliminary study only hints at the possibility of this axis as a target for CNV intervention, and its clinical significance still needs to be validated with larger sample sizes.

Keywords
Choroidal Neovascularization; Age-Related Macular Degeneration; CircRNA MALAT1; miR-96-5p