Investigation of circRNA Expression Profiles and Analysis of circRNA-miRNA-mRNA Networks in an Animal (Mouse) Model of Age-Related Macular Degeneration

Purposes: To (i) identify dysregulated circular RNAs (circRNAs) and (ii) elucidate their potential functions in an animal (mouse) model of choroidal neovascularization (CNV), a prominent feature of neovascular age-related macular degeneration (AMD). Methods: Expression profiles for circRNA were identified by microarray analysis. Selected circRNAs were confirmed by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). Bioinformatic analyses of identified circRNAs were performed to predict (i) circRNA/microRNA interactions and (ii) occurrence of competing endogenous RNA (ceRNA) networks. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were applied to predict both the biological functions and potential pathways of the altered parental genes involved in CNV. Results: Microarray analysis indicated that 100 circRNAs in RPE-choroid-sclera complexes from CNV mice were significantly altered compared with those from control mice (fold change >= 1.5, p < .05). Of these, six were validated by qRT-PCR, and included up-regulated mmu_circRNA_20332 and mmu_circRNA_19388, and down-regulated mmu_circRNA_36481, mmu_circRNA_006555, mmu_circRNA_012588, and mmu_circRNA_005578. GO analysis revealed that the altered parental genes involved in ceRNA networks were mostly enriched in immune system processes and portions of neurons. KEGG analysis revealed that these altered parental genes were also amplified in extracellular matrix (ECM)-receptor interactions, chemokine signaling pathways, and advanced glycation end-product (AGE)-receptors for advanced glycation end-product (RAGE) signaling pathways in diabetic complications. Conclusion: The study identified statistically significant differences between CNV-mouse circRNAs and control mouse circRNAs, suggesting that circRNAs play vital roles in the pathogenesis of CNV. It is, therefore, reasonable to consider circRNAs as potential therapeutic targets for regulating CNV in AMD patients.