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YAN SUN, Lang Xiong, Jingqi huang, Baoxin Chen, Xiaoran Wang, Shan Huang; Autophagy inhibition alleviates TGF-β2-induced epithelial-mesenchymal transition in lens epithelial cells. Invest. Ophthalmol. Vis. Sci. 2020;61(7):5031.
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Posterior capsular opacification (PCO) and anterior subcapsular cataract (ASC) result from pathological epithelial-mesenchymal transition (EMT) of lens epithelial cells (LECs). Autophagy, an evolutionally conserved process for cellular homeostasis, has been reported to play an essential role in fibrotic disorders. Our study is designed to test the hypothesis that inhibition of autophagy can be a potential therapeutic approach to reverse TGF-β2-induced EMT in LECs, which is of critical importance to prevent PCO and ASC.
The primary rabbit LECs (Passage 3 to 5) were treated with TGF-β2 to induce EMT, at various concentrations (2.5nM, 5nM, 10nM) for 2-4 days. 3-methyladenine (3-MA, 2.5mM) and chloroquine (CQ, 50μM) were added for autophagy inhibition with or without TGF-β2 (5nM) for 2 -3 days. The LC3 II/I and P62 levels were detected to assess autophagy levels by western blot and immunofluorescence staining. The mesenchymal markers such as fibronectin, N-cadherin and α-SMA were evaluated by western blot, real-time PCR and immunofluorescence staining. Cell migration was determined by the transwell migration assay.
In the present study, we identified that TGF-β2 promoted autophagy in a time- and dose-dependent manner in LECs, especially in the 10nM-TGF-β2-treated group. Blocking autophagy attenuated TGF-β2-induced EMT in LECs by using autophagy inhibitors including 3-MA and CQ. Co-treatment with TGF-β2 and autophagy inhibitors also blocked TGF-β2-induced pSmad2/3 levels. Transwell migration assay showed that the cell migration properties were impaired during autophagy blockade.
Our data suggest that TGF-β2 can induce autophagy flux in LECs and downregulation of autophagy could attenuate TGF-β2-induced EMT in LECs via Smad signaling pathway. Autophagy inhibition provides a novel therapy strategy for preventing and treating fibrotic cataracts or other fibrotic diseases.
This is a 2020 ARVO Annual Meeting abstract.
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