Abstract
Purpose :
Risuteganib (RSG) is an engineered arginylglycylaspartic acid (RGD)-class synthetic peptide and a first-in-class integrin-regulator for ophthalmology. We previously reported RSG protected against retinal pigment epithelial (RPE) cell injury induced by hydroquinone (HQ), a major oxidant in cigarette smoke and atmospheric pollutants related to the pathogenesis of age-related macular degeneration (AMD). Herein, we explore the potential biological pathways protected by RSG in human RPE cells.
Methods :
Cultured human RPE cells were treated with HQ at different concentrations in the presence or absence of RSG (400 µM, Allegro Ophthalmics, LLC) for various times. Whole transcriptome analysis and gene expression was analyzed via Illumina RNA sequencing and qPCR, respectively. HQ-provoked cell death was evaluated by flow cytometry with Annexin V and 7-AAD. Level of heme oxygenase-1 (HO-1) protein was measured by Western blot. Cytoskeletal F-actin was stained with fluorescent phalloidin and actin aggregates were quantified with Fiji-ImageJ.
Results :
Compared to untreated cells, RSG minimally affected the RPE cell transcriptome, while HQ induced substantial transcriptome changes. A variety of the biological processes and pathways induced by HQ were regulated by RSG+HQ combination treatment including calcium signaling, TGF-β signaling, Ras signaling, cytokine-cytokine receptor interaction, and actin cytoskeleton. Cytoprotection, cellular stress response, unfolded protein response, and nuclear factor erythroid 2-related factor 2 genes were significantly up-regulated by RSG+HQ vs HQ alone (FDR<0.05). HQ induced necrotic cell death to a much greater extent than apoptotic cell death. RSG significantly protected against both necrosis and apoptosis induced by HQ (P<0.05). HO-1 protein levels were significantly upregulated by HQ (P<0.05) and further up-regulated by RSG+HQ (P<0.05). HQ significantly increased F-actin aggregates (P<0.05) while RSG significantly decreased HQ-induced aggregates (P<0.05).
Conclusions :
RSG had no adverse effects on healthy RPE cells. RSG regulated multiple pathways and protected against damaging effects mediated by HQ, implying a potential role for RSG therapy in the treatment of retinal diseases, such as AMD.
This is a 2020 ARVO Annual Meeting abstract.