A Novel Role of ARA70 in Regulating Ferritinophagy of RGCs During Retinal Ischemia Reperfusion.

Although the contribution of ferroptosis, an iron-dependent cell death, to ischemia reperfusion (IR)-induced retinal injury has been reported before, to optimize therapeutic strategy, there is still an urgent need to identify potential candidates involved in this process. Androgen Receptor-Associated Protein of 70 kDa (ARA70) is a cargo receptor for ferritinophagy, and its role in retinal ferroptosis has not been revealed yet. Herein, we explored the role of ARA70 in IR-associated retinal lesions by in vivo (C57BL/6 J mice with intraocular pressure of 90-100 mmHg) and in vitro (retinal ganglion cells (RGCs) stimulated with tert-butyl hydroperoxide (tBH)) experiments. It was found that IR upregulated ARA70 expression and accelerated lipid peroxidation in retinal tissues. We first confirmed that two ferroptosis inhibitors, deferiprone or ferrostatin-1 (Fer-1), suppressed ferritin degradation, restrained apoptosis and inflammation, and protected mouse retinas against IR stress. Next, primary mouse RGCs were treated with tBH to simulate IR environment in vitro . ARA70 expression was decreased at lower concentrations of tBH (5-20 μM), but increased at higher concentrations (40-80 μM). Interestingly, the expression of ferritin-related proteins (ferritin heavy chain, FTH; ferritin light chain, FTL) showed an opposite alteration. Knockdown of ARA70 protected RGCs from tBH-induced damage. It inhibited the delivery of ferritin to lysosomes for ferritinophagy and thus reducing cellular Fe2+ concentration. Besides, ARA70 knockdown suppressed autophagy and inflammation of tBH-treated RGCs. These findings provide novel insights into the pathogenesis of retinal IR, and may be helpful for treatment of retinal diseases.