ASPP2 Upregulation as a Novel Approach to TGF-β2-Induced Proliferative Vitreoretinopathy In Vivo and In Vitro.

Purpose: Proliferative vitreoretinopathy (PVR) can cause blindness and the pathogenesis is unclear. Transforming growth factor (TGF)-β-induced epithelial-mesenchymal transition (EMT) of RPE cells is vital. P53 protein 2 (ASPP2) was previously reported to inhibit EMT in PVR rats, but the specific mechanism is unveiled.

Methods: TGF-β was used to induce EMT in ARPE-19 cells, and evaluated by immunofluorescence and western blot. ARPE-19 cells were transfected with scrambled/ASPP2-lentivirus, followed by TGF-β treatment. After that, alterations of EMT and autophagy were measured by western blot and transmission electron microscopy. Moreover, TGF-β and ARPE-19 cells treated with scrambled/ASPP2-lentivirus were employed to establish the PVR model via intravitreal injection to SD rats, and retinal changes as well as EMT and autophagy activity were evaluated accordingly.

Results: ASPP2 expression was decreased during TGF-β-induced EMT in ARPE-19 cells. In vitro, EMT and autophagy was activated by TGF-β, which could be partly reversed by ASPP2 upregulation. In vivo, ASPP2 upregulation protected against structural and functional changes in PVR retinas. Additionally, expressions of EMT and autophagy markers in retinas were inhibited by ASPP2 upregulation.

Conclusions: ASPP2 upregulation inhibited the EMT and autophagy process caused by TGF-β in ARPE-19 cells. Correspondingly, upregulation of ASPP2 alleviated intraocular fibrosis and protected visual function in PVR rats.