title: Identification of small molecule NPR-B antagonists by high throughput screening--potential use in heart failure.
abstract: We found previously that stimulation of natriuretic peptide receptor (NPR)-B by C-type natriuretic peptide (CNP) in failing rat ventricle potentiates β1-adrenoceptor (β1-AR)-mediated inotropic response to noradrenaline through cGMP-mediated inhibition of phosphodiesterase (PDE) 3, thereby enhancing cAMP-mediated signalling. Increased cAMP-mediated signalling is deleterious in chronic heart failure (HF; basis for the use of β-blockers in HF) and we propose to consider NPR-B antagonists as new HF treatment in addition to conventional therapy. Since there is no NPR-B-selective antagonist available for clinical studies, we aimed at identifying a novel small molecule (non-peptide) NPR-B antagonist. An assay was developed and high throughput screening performed on a chemical library of about 20,000 small molecule compounds (<500 Da) to identify NPR-B antagonists based on inhibition of CNP-stimulated cGMP production in NPR-B-expressing HEK293 cells. The screen revealed several potential NPR-B antagonists, of which six were selected for further studies. Three showed selective NPR-B vs NPR-A inhibition and three were partially selective. The compounds mediated reversible, noncompetitive inhibition and most likely act as allosteric modulators binding outside the agonist binding site of NPR-B. In rat ventricular muscle strips, the potentiating effect of CNP upon β1-AR-evoked inotropic effects could be attenuated by at least one of these compounds. We identified several small molecule NPR-B antagonists by high throughput screening and show in a functional heart preparation that blocking NPR-B stimulation with a small molecule compound can reduce the potentiating effect of CNP on the β1-AR-mediated inotropic response to noradrenaline.
authors.affiliation: Department of Pharmacology, Faculty of Medicine, University of Oslo and Oslo University Hospital, Sognsvannsveien 20, P.O. Box 1057, Blindern, 0316, Oslo, Norway.
authors.forename: Trond
authors.initials: T
authors.lastname: Bach
authors.forename: Stine
authors.initials: S
authors.lastname: Bergholtz
authors.forename: Jon
authors.initials: J
authors.lastname: Riise
authors.forename: Eirik
authors.initials: E
authors.lastname: Qvigstad
authors.forename: Tor
authors.initials: T
authors.lastname: Skomedal
authors.forename: Jan-Bjørn
authors.initials: JB
authors.lastname: Osnes
authors.forename: Finn Olav
authors.initials: FO
authors.lastname: Levy
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004353:Drug Evaluation, Preclinical / Q000379:methods; D057809:HEK293 Cells; D006333:Heart Failure / Q000175:diagnosis* / Q000188:drug therapy* / Q000235:genetics; D006352:Heart Ventricles / Q000187:drug effects; D057166:High-Throughput Screening Assays / Q000379:methods / Q000706:statistics & numerical data*; D006801:Humans; D008969:Molecular Sequence Data; D009924:Organ Culture Techniques; D051381:Rats; D017461:Receptors, Atrial Natriuretic Factor / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D000099242:Atrial Natriuretic Factor Receptor B
chemical_list: D017461:Receptors, Atrial Natriuretic Factor; D000099242:Atrial Natriuretic Factor Receptor B