Autophagy dysregulation mediates the damage of high glucose to retinal pigment epithelium cells

Aim: To observe the role and mechanism of Autophagy in retinal pigment epithelial cell (RPE) damaged by high glucose, so as to offer a new idea for the treatment of diabetic retinopathy (DR).

Methods: ARPE-19, a human RPE cell line cultured in vitro was divided into the normal control (NC), Autophagy Inhibitor 3-methyladenine (3-MA), high-glucose (HG), and HG+3-MA groups. Cell viability was detected by CCK-8 assay and the Apoptosis rate was measured by flow cytometry. The protein expressions of Apoptosis markers, including Bax, Bcl-2, and Caspase-3, as well as Autophagy marker including microtubule-related protein 1 light chain 3 (LC3), p62, and mechanistic target of rapamycin (mTOR) were detected by Western blotting. Autophagic flux was detected by transfection with Ad-mCherry-GFP-LC3B.

Results: Under high glucose conditions, the viability of ARPE-19 was decreased, and the Apoptosis rate increased, the protein expressions of Bax, Caspase-3, and LC3-II/LC3-I were all increased and the expressions of Bcl-2, p62 and p-mTOR decreased, and autophagic flux was increased compared with that of the controls. Treatment with 3-MA reversed all these changes caused by high glucose.

Conclusion: The current study demonstrates the mechanisms of cell damage of ARPE-19 through high glucose/mTOR/Autophagy/Apoptosis pathway, and new strategies for DR may be developed based on Autophagy regulation to manage cell death of RPE cells.