TXNIP positively regulates the autophagy and apoptosis in the rat müller cell of diabetic retinopathy.

AIMS: Diabetic retinopathy (DR) can cause vision loss in patients with diabetes. The present study evaluated the expression of thioredoxin interacting protein (TXNIP) and investigated the role of TXNIP in autophagy and apoptosis of DR. MAIN METHODS: Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting were used to measure the expression level of the targets. Clustered regularly interspaced short palindromic repeats/CRISPR-associated 9 (CRISPR/cas9) method was applied for knockout of TXNIP. TdT-mediated dUTP Nick-End Labeling (TUNEL) assay and flow cytometry were utilized to detect the apoptosis. Cell Counting Kit-8 (CCK-8) assay was used to evaluate the cell viability. EdU assay was carried out to measure the cell proliferation ability. Retinal immunohistochemistry, retinal frozen section immunofluorescence as well as the electroretinogram (ERG) recording were implemented to detect the function of the retina. KEY FINDINGS: TXNIP was up-regulated under hyperglycemic condition both in vivo and in vitro. Overexpression of TXNIP activated the autophagy and apoptosis in the rat müller cell. Knockout of TXNIP reduced the autophagy and apoptosis in the rat müller cell under high glucose condition. TXNIP positively regulates autophagy via inhibition of the PI3K/AKT/mTOR signaling pathway. Knockdown of TXNIP improved the visual response to light stimulus of DR. SIGNIFICANCE: Our study unraveled for the first time that TXNIP positively regulates the autophagy in rat müller cell under high glucose condition by inhibiting the PI3K/AKT/mTOR signaling pathway, providing a novel understanding in the pathogenesis of DR and suggesting a potential new therapeutic target of DR.

Egr1 mediates retinal vascular dysfunction in diabetes mellitus via promoting p53 transcription.

OBJECTIVES: This study focused on investigating the expression and underlying molecular mechanism of early growth response 1 (Egr1) in diabetic retinopathy. METHODS: A microarray assay was applied to examine differentially expressed genes in the retina tissues of normal rats, as well as in those of streptozotocin-induced diabetic rats. Human retinal vascular endothelial cells (HRVECs) transfected with sh-NC, sh-Egr1 or sh-Egr1+ pVax1-p53 were cultured under high-glucose conditions and then used to explore the role of Egr1 in vitro. The effect of Egr1 on retinal vascular dysfunction caused by diabetes was examined by sh-Egr1 administration in vivo RESULTS: Early growth response 1 was found to be up-regulated in the retinas of diabetic rats compared to those of normal rats. Down-regulation of Egr1 in HRVECs under high-glucose conditions inhibited the apoptosis, migration and tube formation in vitro. Moreover, sh-Egr1 partially reduced the injurious effects of hyperglycaemia on retinal vascular function by decreasing apoptotic cells and microvascular formation in vivo. The reduction of Egr1 evidently down-regulated the p53 expression. Overexpression of p53 rescued the inhibition of sh-Egr1 in HRVECs under high-glucose concentration on apoptosis, migration and tube formation in vitro. CONCLUSION: Down-regulation of Egr1 partially reduced the injurious effects of hyperglycaemia on retinal vascular function via inhibiting p53 expression.