Abstract
Purpose :
Dry age-related macular degeneration (AMD) manifests the accumulation of drusen under the Brunch's membrane of which amyloid beta is speculated to be the key factor of AMD pathology. The detrimental role of Aβ on retina has been widely explored while Aβ-induced epigenetic changes have not been fully investigated. We therefore intended to identify the microRNA (miRNA) expression profiles in an Aβ-induced model of retinal degeneration.
Methods :
Two-month-old male C57BL/6 mice were intravitreally injected Aβ1-40 (7μg／5μL) or PBS (5μL). Two days later, animals were euthanized and eye tissues were collected for hematoxylin and eosin (H&E) stain, Annexin V-FITC/PI assay and miRNA assay. A scatter plot was generated to assess the quality of the miRNA data after filtering and a volcano plot was generated to visualize the differential expressions. Top 5 up- and down-regulated miRNAs were analyzed by Gene Ontology (GO) and pathway analysis.
Results :
H&E-stained sections of retinal pigment epithelium (RPE)/neural retina tissue showed retinal alternations including the disorganization of the outer retina and RPE vacuolation and hypopigmentation in the model group. Immunofluorescence V-FITC/PI assay revealed that the level of apoptosis increased in the outer retina including the outer plexiform layer (OPL) and outer nuclear layer (ONL) compared to the controls 48 hrs after Aβ injections. MicroRNA profiling revealed 61 miRNAs differentially expressed between the Aβ-injected and the control group. Among which, 38 miRNAs were upregulated (fold change>1.5, p<0.05) and 23 miRNAs were downregulated (fold change<0.667, p<0.05). The top 5 up-regulated miRNA (mmu-miR-223-3p, mmu-miR-216b-5p, mmu-miR-155-5p, mmu-miR-142a-3p, mmu-miR-33-5p) and down-regulated miRNA (mmu-miR-200b-3p, mmu-miR-744-5p, mmu-miR-1224-5p, mmu-miR-433-3p, mmu-miR-298-5p) were chosen for further GO and pathway analyses. According to these results, the ubiquitin mediated proteolysis, the MAPK signaling pathway and the neurotrophin signaling pathway might be involved in the molecular mechanisms underlying the Aβ-induced retinal degeneration.
Conclusions :
Our study firstly profiled the miRNA expression patterns in an Aβ-induced experimental retina degeneration model that simulated the pathology of the early stage and progression of dry AMD. Our results implied novel targets for a major cause of blindness.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.