title: Structure Guided Chemical Modifications of Propylthiouracil Reveal Novel Small Molecule Inhibitors of Cytochrome b5 Reductase 3 That Increase Nitric Oxide Bioavailability.
abstract: NADH cytochrome b5 reductase 3 (CYB5R3) is critical for reductive reactions such as fatty acid elongation, cholesterol biosynthesis, drug metabolism, and methemoglobin reduction. Although the physiological and metabolic importance of CYB5R3 has been established in hepatocytes and erythrocytes, emerging investigations suggest that CYB5R3 is critical for nitric oxide signaling and vascular function. However, advancement toward fully understanding CYB5R3 function has been limited due to a lack of potent small molecule inhibitors. Because of this restriction, we modeled the binding mode of propylthiouracil, a weak inhibitor of CYB5R3 (IC50 = ∼275 μM), and used it as a guide to predict thiouracil-biased inhibitors from the set of commercially available compounds in the ZINC database. Using this approach, we validated two new potent derivatives of propylthiouracil, ZINC05626394 (IC50 = 10.81 μM) and ZINC39395747 (IC50 = 9.14 μM), both of which inhibit CYB5R3 activity in cultured cells. Moreover, we found that ZINC39395747 significantly increased NO bioavailability in renal vascular cells, augmented renal blood flow, and decreased systemic blood pressure in response to vasoconstrictors in spontaneously hypertensive rats. These compounds will serve as a new tool to examine the biological functions of CYB5R3 in physiology and disease and also as a platform for new drug development.
authors.affiliation: From the Heart, Lung, Blood, and Vascular Medicine Institute.
authors.forename: Md Mizanur
authors.initials: MM
authors.lastname: Rahaman
authors.affiliation: Department of Computational and Systems Biology.
authors.forename: Fabio G
authors.initials: FG
authors.lastname: Reinders
authors.affiliation: Department of Computational and Systems Biology.
authors.forename: David
authors.initials: D
authors.lastname: Koes
authors.affiliation: From the Heart, Lung, Blood, and Vascular Medicine Institute.
authors.forename: Anh T
authors.initials: AT
authors.lastname: Nguyen
authors.affiliation: From the Heart, Lung, Blood, and Vascular Medicine Institute, Department of Pharmacology and Chemical Biology, and.
authors.forename: Stephanie M
authors.initials: SM
authors.lastname: Mutchler
authors.affiliation: From the Heart, Lung, Blood, and Vascular Medicine Institute.
authors.forename: Courtney
authors.initials: C
authors.lastname: Sparacino-Watkins
authors.affiliation: From the Heart, Lung, Blood, and Vascular Medicine Institute, Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15213.
authors.forename: Roger A
authors.initials: RA
authors.lastname: Alvarez
authors.affiliation: From the Heart, Lung, Blood, and Vascular Medicine Institute.
authors.forename: Megan P
authors.initials: MP
authors.lastname: Miller
authors.affiliation: Department of Pharmacology and Chemical Biology, and.
authors.forename: Dongmei
authors.initials: D
authors.lastname: Cheng
authors.affiliation: Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15213.
authors.forename: Bill B
authors.initials: BB
authors.lastname: Chen
authors.affiliation: Department of Pharmacology and Chemical Biology, and.
authors.forename: Edwin K
authors.initials: EK
authors.lastname: Jackson
authors.affiliation: Department of Computational and Systems Biology.
authors.forename: Carlos J
authors.initials: CJ
authors.lastname: Camacho
authors.affiliation: From the Heart, Lung, Blood, and Vascular Medicine Institute, Department of Pharmacology and Chemical Biology, and astraub@pitt.edu.
authors.forename: Adam C
authors.initials: AC
authors.lastname: Straub
mesh_terms: D000818:Animals; D042966:Cytochrome-B(5) Reductase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D015195:Drug Design; D004791:Enzyme Inhibitors / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D015394:Molecular Structure; D009569:Nitric Oxide / Q000378:metabolism*; D011441:Propylthiouracil / Q000737:chemistry* / Q000378:metabolism; D051381:Rats
chemical_list: D004791:Enzyme Inhibitors; D009569:Nitric Oxide; D011441:Propylthiouracil; D042966:Cytochrome-B(5) Reductase
keywords: computational biology; cytochrome b5 reductase 3; hemoglobin; nitric oxide; oxidation-reduction (redox); vascular