Abstract
Purpose :
Retinal and corneal disorders that stem from mitochondrial dysfunction, including macular degeneration and Fuchs’ dystrophy, exhibit oxidative stress and increased inflammatory activity as key contributors to their pathogenesis. Nuclear factor erythroid 2-related factor 2 (NRF2) is a transcription factor that regulates proteins required for normal mitochondrial function, removal of cellular oxidants, and control of the inflammatory response, and represents a therapeutic target to restore normal cellular function. We have performed in vitro studies designed to determine the activity, potency, selectivity, and cytotoxicity of a novel NRF2 activator, SCO-116, for ocular use.
Methods :
Time-resolved fluorescence resonance energy transfer (TR-FRET) was used to determine the activity of SCO-116 to release NRF2 from its negative regulator, KEAP1, following a 1-h incubation. The ability of SCO-116 to activate the antioxidant response element was measured in HEK293T cells transfected with antioxidant response element-Nano-luc reporter following a 6-h incubation with SCO-116 or vehicle. Cytotoxicity was also examined in separate experiments in HMEC-1, AC16, and HK2 cells incubated for 24-48 h with either SCO-116 or vehicle, with ATP content measured using CellTiter Glo. Finally, a Eurofins SafetyScreen panel was performed, to assess SCO-116 interaction with a series of 87 G-protein-coupled receptors, ion channels, enzymes, transporters, and nuclear receptors.
Results :
SCO-116 exhibited potent inhibition of the KEAP1-NRF2 interaction in a cell-free system (IC50 0.28 nM). This correlated with the ability of SCO-116 to activate the antioxidant response element in HEK293 cells (EC30 37 nM). This activity was not associated with cytotoxicity; no decrease in ATP content was detected in any cell type evaluated at any concentration tested (up to 30 µM). Finally, a broad cell-based selectivity screen of SCO-116 at 100 nM revealed no significant inhibition of any of the 87 targets assayed.
Conclusions :
SCO-116 has been identified as a novel NRF2 activator, and the present data demonstrate potent interaction with its molecular target (KEAP1) and subsequent activation of NRF2 at concentrations not associated with cytotoxicity or off-target effects. SCO-116 is currently under investigation for treatment of both macular degeneration and Fuchs’ dystrophy, and these data support this continued evaluation.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.