MiR-21-5p promotes RPE cell necroptosis by targeting Peli1 in a rat model of AMD

Nonexudative age-related macular degeneration (dry AMD) is characterized by the progressive degeneration of retinal pigment epithelial (RPE) cells and photoreceptors, resulting in central vision loss. The disease is primarily marked by the accumulation of drusen and RPE atrophy. Given the emerging role of miR-21-5p in various ocular diseases, including diabetic retinopathy, glaucoma, pterygium, and choroidal neovascularization, we hypothesized that miR-21-5p may also impact RPE cell integrity in AMD. To test this hypothesis, we employed a rat model of dry AMD induced by sodium iodate (NaIO3) and evaluated the effects of miR-21-5p modulation via intravitreal injections of miR-21-5p agomir or antagomir. Comprehensive assessments were performed using optical coherence tomography (OCT), fundus imaging, histopathology, and biochemical markers. Our results demonstrated an upregulation of miR-21-5p in response to NaIO3 treatment. Administration of miR-21-5p agomir exacerbated RPE damage, while pretreatment with miR-21-5p antagomir mitigated these detrimental effects. Furthermore, in vitro experiments revealed that miR-21-5p regulates necroptosis in CoCl2-treated RPE cells by targeting Pellino1 (Peli1) via its 3' untranslated region, thereby inhibiting Peli1 expression. Overexpression of Peli1 effectively counteracted the necroptotic effects induced by CoCl2. These findings highlight the potential of miR-21-5p as a therapeutic target in dry AMD, expanding our understanding of miRNA-mediated regulation of RPE cells and suggesting new avenues for treatment strategies.