BACKGROUND: The aim of this study was to explore the role of MIAT (myocardial infarction related transcripts) in diabetic optic neuropathy and its underlying mechanism.

MATERIAL AND METHODS: QRT-PCR (quantitative real-time polymerase chain reaction) was performed to detect the mRNA levels of MIAT and HSPA5 (heart shock protein 5) in diabetic rat model and high-glucose cultured Müller cells. After the intracellular MIAT level was increased by lentivirus transfection, the proliferation, cell cycle, and apoptosis of Müller cells were measured using the CCK-8 (Cell Counting Kit-8) assay, flow cytometry, and TUNEL (terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling) assay, respectively. Mechanisms underlying the MIAT-related apoptosis were explored by Western blot analysis. The binding condition of microRNA-379 to MIAT and HSPA5 was confirmed by luciferase reporter gene assay.

RESULTS: Both MIAT and HSPA5 levels were remarkably increased in high-glucose cultured Müller cells. After transfected with LV (lentivirus)-MIAT, Müller cells showed a decreased proliferation and an enhanced apoptosis with the increased expressions of pro-apoptotic proteins. However, no remarkable changes were observed in cell cycle. Further mechanistic studies found that MIAT regulated HSPA5 expression by directly binding to microRNA-379.

CONCLUSIONS: MIAT was overexpressed in the diabetic optic nerve. MIAT overexpression remarkably promoted the apoptosis of Müller cells by adsorbing microRNA-379 and thus regulating HSPA5, which was a direct target of microRNA-379.

Keywords: Diabetes Complications, Optic Nerve Injuries, Binding, Competitive, Diabetes Mellitus, Experimental, Diabetic Neuropathies, Ependymoglial Cells, Heat-Shock Proteins, Optic Nerve, RNA, Messenger