Abstract
Purpose :
Risuteganib (RSG) is a novel synthetic peptide that regulates integrin functions and has shown promising efficacy in an intermediate dry AMD phase 2 clinical study. We previously reported that RSG protected against retinal pigment epithelial (RPE) cell injury induced by hydroquinone (HQ), a major oxidant in cigarette smoke and atmospheric pollutants, agents implicated in age-related macular degeneration (AMD) pathogenesis. Many transcription factors (TFs) are important regulators of genes that control cellular response to oxidative stress. Herein, we investigate the effect of RSG on expression of several TFs regulated by HQ in human RPE cells.
Methods :
Cultured human RPE cells in triplicate wells were treated with HQ at different concentrations in the presence or absence of RSG (400 µM, Allegro Ophthalmics, LLC) for various treatment times. Expression of TF genes associated with cellular stress response, including activating transcription factor 3 (ATF3), DNA damage-inducible transcript 3 (DDIT3; encodes the multifunctional TF, CHOP), and DNA-binding protein inhibitors (ID-2 and ID-3), were analyzed by qPCR. Expression of ATF3, CHOP, nuclear factor erythroid 2-related factor 2 (NRF2), and X-box binding protein 1s (XBP1) were evaluated by Western blot.
Results :
Compared to untreated cells, HQ significantly increased mRNA expression of ATF3, DDIT3, ID2 and ID3 (P<0.05). RSG+HQ cotreatment significantly further upregulated HQ-induced ATF3 and DDIT3 (P<0.05) and decreased HQ-induced ID2 and ID3 mRNA levels (P<0.05). Levels of ATF3, Nrf2, CHOP, XBP1 proteins were significantly upregulated by HQ and further upregulated by RSG+HQ cotreatment (P<0.05).
Conclusions :
RSG modulated multiple transcription factors involved in oxidant injury pathways, supporting a multifunctional role of RSG on RPE cells against oxidative stress.
This is a 2021 ARVO Annual Meeting abstract.