Discovery of GSK2795039, a Novel Small Molecule NADPH Oxidase 2 Inhibitor

Abstract

Aims: The NADPH oxidase (NOX) family of enzymes catalyzes the formation of reactive oxygen species (ROS). NOX enzymes not only have a key role in a variety of physiological processes but also contribute to oxidative stress in certain disease states. To date, while numerous small molecule inhibitors have been reported (in particular for NOX2), none have demonstrated inhibitory activity in vivo. As such, there is a need for the identification of improved NOX inhibitors to enable further evaluation of the biological functions of NOX enzymes in vivo as well as the therapeutic potential of NOX inhibition. In this study, both the in vitro and in vivo pharmacological profiles of GSK2795039, a novel NOX2 inhibitor, were characterized in comparison with other published NOX inhibitors. Results: GSK2795039 inhibited both the formation of ROS and the utilization of the enzyme substrates, NADPH and oxygen, in a variety of semirecombinant cell-free and cellbased NOX2 assays. It inhibited NOX2 in an NADPH competitive manner and was selective over other NOX isoforms, xanthine oxidase, and endothelial nitric oxide synthase enzymes. Following systemic administration in mice, GSK2795039 abolished the production of ROS by activated NOX2 enzyme in a paw inflammation model. Furthermore, GSK2795039 showed activity in a murine model of acute pancreatitis, reducing the levels of serum amylase triggered by systemic injection of cerulein. Innovation and Conclusions: GSK2795039 is a novel NOX2 inhibitor that is the first small molecule to demonstrate inhibition of the NOX2 enzyme in vivo. Antioxid. Redox Signal. 23, 358-374.

NOX Activation by Subunit Interaction and Underlying Mechanisms in Disease

“…GSK2795039, a small molecular inhibitor, has been recently developed and was found to be protective in paw inflammation and acute pancreatitis mouse models. Unlike DPI, it is specific to NOX2, demonstrating reduction in NOX2 activity via competitive inhibition with little to no inhibition of other NOX isoforms and other flavoenzymes, such as xanthine oxidase or nitric oxide synthase (Hirano et al, 2015). Given the increasing evidence for NOX2’s role in such conditions as stroke and the moderate bioavailability of the drug in the brain, the inhibitor has potential in treating ischemia and neurodegenerative disorders as well (Kahles and Brandes, 2013; Hirano et al, 2015).…”

Anti-Inflammatory Small Molecules To Treat Seizures and Epilepsy: From Bench to Bedside

“…For instance, apocynin shows marked ROS scavenging activity and inhibition on rho kinases; DPI is a general inhibitor of flavoproteins, e.g., xanthine oxidase and endothelial nitric oxide synthase (eNOS) [115]. Owing to recent advances in chemical biology and HTS, several new classes of small-molecule NOX inhibitors with improved specificity have been identified [115–117]. However, whether these novel NOX2 inhibitors would show any antiepileptic or antiepileptogenic effect in animal models requires investigation.…”

Mitigation of NADPH Oxidase 2 Activity as a Strategy to Inhibit Peroxynitrite Formation

“…Many HTS-based H 2 O 2 assays to detect Nox inhibitors included the enzyme HRP. The lack of probes' selectivity for specific oxidant and the susceptibility of the HTS assays to peroxidase substrates and inhibitors led to the controversy over the Nox-inhibitory potency of the positive hits selected, including apocynin, VAS2870, and 2-acetylphenothiazine (36,60,61). In fact, one of the authors recently reported a new myeloperoxidase inhibitor, identified during the HTS campaign for Nox2 inhibitors, using the L-012 probe as a Nox2 activity reporter (62).…”