Invited Review SeriesMyocardial Phosphodiesterases and Their Role in cGMP RegulationDunkerly-Eyring, Brittany BA*,†; Kass, David A. MD*,†Author Information *Department of Medicine, Division of Cardiology, Baltimore, MD; and †Department of Pharmacology and Molecular Sciences, Baltimore, MD. Reprints: David A. Kass, MD, Johns Hopkins Medical Institutions, Ross Research Building, Room 858, 720 Rutland Avenue, Baltimore, MD 21205 (e-mail: firstname.lastname@example.org). D. A. Kass receives research funding and is an advisor to Intracellular Therapies Inc., a pharmaceutical company developing PDE1 inhibitors for cardiac and other medical indications. He is also an advisor to Cardurion Pharmaceuticals Inc., a company pursuing the use of PDE9A inhibitors for cardiac indications. The remaining authors have no conflicts of interests to disclose. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (www.jcvp.org). Received June 06, 2019 Accepted September 30, 2019 Online date: October 22, 2019 Journal of Cardiovascular Pharmacology: June 2020 - Volume 75 - Issue 6 - p 483-493 doi: 10.1097/FJC.0000000000000773 Buy SDC Metrics Abstract Cyclic nucleotide phosphodiesterases comprise an 11-member superfamily yielding near 100 isoform variants that hydrolyze cAMP or cGMP to their respective 5′-monophosphate form. Each plays a role in compartmentalized cyclic nucleotide signaling, with varying selectivity for each substrate, and conveying cell and intracellular-specific localized control. This review focuses on the 5 phosphodiesterases (PDEs) expressed in the cardiac myocyte capable of hydrolyzing cGMP and that have been shown to play a role in cardiac physiological and pathological processes. PDE1, PDE2, and PDE3 catabolize cAMP as well, whereas PDE5 and PDE9 are cGMP selective. PDE3 and PDE5 are already in clinical use, the former for heart failure, and PDE1, PDE9, and PDE5 are all being actively studied for this indication in patients. Research in just the past few years has revealed many novel cardiac influences of each isoform, expanding the therapeutic potential from their selective pharmacological blockade or in some instances, activation. PDE1C inhibition was found to confer cell survival protection and enhance cardiac contractility, whereas PDE2 inhibition or activation induces beneficial effects in hypertrophied or failing hearts, respectively. PDE3 inhibition is already clinically used to treat acute decompensated heart failure, although toxicity has precluded its long-term use. However, newer approaches including isoform-specific allosteric modulation may change this. Finally, inhibition of PDE5A and PDE9A counter pathological remodeling of the heart and are both being pursued in clinical trials. Here, we discuss recent research advances in each of these PDEs, their impact on the myocardium, and cardiac therapeutic potential. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.