Genipin protects against mitochondrial damage of the retinal pigment epithelium under hyperglycemia through the AKT pathway mediated by the miR-4429/JAK2 signaling axis

BACKGROUND: To investigate the protective effect and mechanism of genipin (GE) on mitochondrial damage in retinal pigment epithelial (RPE) cells induced by high glucose. METHODS: Differential genes of GE in the treatment of diabetic retinopathy (DR) were screened by the Gene Expression Omnibus (GEO) database. Differential genes located in the AKT pathway were obtained. TargetScan, miRDB, and DIANA databases were used to predict the targeted microRNAs (miRNAs) of differential genes. A high-fat diet combined with streptomycin (STZ) intraperitoneal injection were used to establish a diabetic mouse model. Diabetic mice were treated with GE by intragastric administration. The functional and molecular changes of the retina were detected by electroretinogram (ERG) and reverse transcription-polymerase chain reaction (RT-PCR). ARPE-19 cells were cultured under hyperglycemic conditions with AKT and JAK2 inhibitors. MiR-4429 was knocked down/overexpressed to detect changes in cell function, activity, and mitochondrial function. The dual luciferase reporter assay confirmed the targeted binding of miR-4429 with JAK2. RESULTS: Bioinformatics analysis finally yielded JAK2 as the research target gene. miR-4429 was predicted to be the targeted miRNA of JAK2 by online databases. The results of animal experiments showed that the retinal function of mice recovered after GE administration (P<0.05), the expression of AKT and miR-4429 in RPE cells was significantly increased (P<0.05), and the expression of JAK2 was significantly decreased (P<0.05). The results of cell experiments showed that the functions of cells and mitochondria recovered after the addition of GE under hyperglycemia (P<0.05). Cell and mitochondrial functions were decreased after the addition of AKT inhibitor (P<0.05). Overexpression of miR-4429 or inhibition of JAK2 increased cell activity and mitochondrial function (P<0.05). The results of the dual luciferase reporter assay showed that miR-4429 had a targeted binding site with JAK2. CONCLUSIONS: GE protects ARPE-19 cell functional activity, inflammatory responses, and mitochondrial damage by promoting the AKT signaling pathway and regulating the expression of the miR-4429/JAK2 signaling axis.