c-Jun mediated microRNA-302d-3p induces RPE dedifferentiation and CNV formation by targeting p21^Waf1/Cip1

Abstract

Purpose : Dedifferentiation of retinal pigment epithelium (RPE) and choroidal neovascularization (CNV) contributes to the pathogenesis of age-related macular degeneration (AMD). MicroRNAs (miRNAs) play crucial roles in AMD onset and progression. We aim to illustrate the effects and mechanisms of miRNAs on RPE dedifferentiation and CNV formation.

Methods : Microarray was applied to identify RPE differentiation relevant miRNAs. Bioinformatics analysis and luciferase reporter assay were performed to identify the up-stream transcript factor (TF) and down-stream target of miR-302d-3p. Q-PCR, western blot, immunofluorescence, flow cytometric analysis, analyses of proliferation and migration, and tube formation assay were conducted to reveal the role of miR-302d-3p in regulating RPE function and CNV formation.

Results : Microarray identified miR-302d-3p as the most down-regulated miRNA signature along with RPE differentiation. In vitro study further supported that miR-302d-3p induces RPE dedifferentiation and apoptosis, promotes its migration, proliferation and cell-cycle progression, and interrupted its phagocytosis. c-Jun was identified as a upstream TF for MIR302D, which potentially modulated RPE function by regulating miR-302d-3p expression. P21^Waf1/Cip1, a cyclin-dependent kinase inhibitor encoded by the CDKN1A gene, was identified as a down-stream target of miR-302d-3p. P21^Waf1/Cip1 promoted RPE differentiation, and inhibited its proliferation, migration and cell-cycle progression. MiR-302d-3p suppressed RPE differentiation through directly targeting p21^Waf1/Cip1. In addition, the miR-302d-3p/ p21^Waf1/Cip1 axis was also involved in regulating tube formation of endothelial cells, suggesting its role in CNV generation.

Conclusions : Our study implies that miR-302d-3p, regulated by c-Jun, contributes to the pathogenesis of both atrophic and exudative AMD. MiR-302d-3p promotes RPE dedifferentiation, migration, proliferation, cell-cycle progression and apoptosis, inhibits RPE phagocytosis, and induces CNV by targeting p21^Waf1/Cip1. Pharmacological miR-302d-3p inhibitors are prospective therapeutic options for prevention and treatment of AMD.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.

 

c-Jun mediated miR-302d-3p inhibits RPE differentiation and phagocytosis, and promotes RPE apoptosis, proliferation, migration and cell-cycle progression.

 

MiR-302d-3p mediates RPE function and HUVEC tube formation by directly targeting p21^Waf1/Cip1.