MC-released exosomal miR-92a-3p transmits IL-17A signal by inhibiting the target Notch-1 to accelerate DR progression. An intravitreal administration of exosomes containing miR-92a-3p inhibitor may become a potential therapeutic strategy for DR.

Exosomes isolated from primarily cultured MCs were identified and high-throughput sequencing was used to indicate differentially expressed miRNAs in the exosomes. Targeting relationship of miR-92a-3p and Notch-1 was determined by dual-luciferase reporter assay. MCs were treated with high glucose (HG), IL-17A, anti-IL-17A antibody, miR-92a-3p inhibitor, or/and miR-92a-3p mimic, and exosomes derived from MCs with the various treatments were applied to primary RGCs. DR mice were induced by streptozotocin (STZ) and subjected to intravitreal injection.

Inflammatory processes have been involved in diabetic retinopathy (DR). Interleukin (IL)-17A, a pro-inflammatory cytokine, is associated with DR occurrence and development. However, mechanisms underlying the IL-17A impact on DR need further investigations. Herein, we show that exosomal miRNA delivers IL-17A signal from Müller cells (MCs) to retinal ganglion cells (RGCs) to facilitate DR.

Expression of miR-92a-3p in exosomes derived from MCs with IL-17A treatment in either the absence or the presence of HG was upregulated, and the IL-17A effect was blocked by anti-IL-17A antibody. The exosomes derived from IL-17A-treated MCs downregulated Notch-1 expression in recipient RGCs and increased the neuronal death. These effects of IL-17A were suppressed by miR-92a-3p inhibitor but enhanced by miR-92a-3p mimic. In STZ mice, intravitreal administration of exosomes derived from IL-17A-treated MCs downregulated retinal Notch-1 expression and increased RGC apoptosis. These IL-17A effects were hindered by miR-92a-3p inhibitor. Conclusions: MC-released exosomal miR-92a-3p transmits IL-17A signal by inhibiting the target Notch-1 to accelerate DR progression. An intravitreal administration of exosomes containing miR-92a-3p inhibitor may become a potential therapeutic strategy for DR.