Development of a first-in-class homolog-selective, covalent NOX4 inhibitor
Mariana Castelôa1, Sara Marchese2, Marta Massari2
1RISE-Health, Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Rua do Campo Alegre, s/n, Porto 4169-007, Portugal.
Abstract:
The NADPH oxidase (NOX) family in humans includes seven enzymes whose main function is to produce reactive oxygen species. Because of their role in oxidative damage, these enzymes are being explored as targets for new therapies against oxidative stress-related diseases. However, their conserved catalytic core poses selective inhibition challenging. Current inhibitors suffer from low potency, cytotoxicity, assay interference, and poor selectivity. VAS2870, a covalent NOX inhibitor targeting a cysteine in the dehydrogenase (DH) domain, does not present assay interference but still shows limited selectivity, solubility, and safety. This study aimed to develop improved VAS2870-based targeted covalent inhibitors (TCIs) by designing and screening a library of cysteine-targeting compounds against NOX1, NOX2, NOX4, and NOX5. A hit compound, compound 2, was optimized, yielding a potent, homolog-selective NOX4 inhibitor, compound 18. Its mechanism of action was validated, demonstrating covalent binding to a cysteine residue and showing that compound binding is hindered by the presence of FAD in the DH domain.
Insights
Researchers developed novel targeted covalent inhibitors (TCIs) to selectively block NADPH oxidase (NOX) enzymes, which are implicated in oxidative stress diseases. A new compound effectively inhibits NOX4, offering a promising therapeutic avenue.
Area of Science:
- Biochemistry
- Pharmacology
- Medicinal Chemistry
Background:
- NADPH oxidase (NOX) enzymes produce reactive oxygen species, contributing to oxidative stress and related diseases.
- Targeting NOX enzymes is a therapeutic strategy, but selective inhibition is challenging due to conserved catalytic cores.
- Existing NOX inhibitors like VAS2870 have limitations in selectivity, solubility, and safety.
Purpose of the Study:
- To design and screen novel VAS2870-based targeted covalent inhibitors (TCIs).
- To identify potent and selective inhibitors against NOX1, NOX2, NOX4, and NOX5.
- To optimize a lead compound for improved therapeutic properties.
Main Methods:
- Designed and synthesized a library of cysteine-targeting compounds.
- Screened compounds against NOX1, NOX2, NOX4, and NOX5.
- Optimized a hit compound (compound 2) to yield compound 18.
- Validated the mechanism of action, including covalent binding and FAD influence.
Main Results:
- Identified a potent, homolog-selective NOX4 inhibitor (compound 18).
- Validated covalent binding to a cysteine residue.
- Demonstrated that FAD presence in the dehydrogenase domain hinders compound binding.
Conclusions:
- Developed a novel, potent, and selective NOX4 inhibitor.
- TCIs represent a promising approach for targeting NOX enzymes.
- Understanding FAD's role provides insights for future inhibitor design.
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