Cyclic guanosine monophosphate (cGMP) is a second messenger molecule that transduces nitric-oxide- and natriuretic-peptide-coupled signalling, stimulating phosphorylation changes by protein kinase G. Enhancing cGMP synthesis or blocking its degradation by phosphodiesterase type 5A (PDE5A) protects against cardiovascular disease1,2. However, cGMP stimulation alone is limited by counter-adaptions including PDE upregulation3. Furthermore, although PDE5A regulates nitric-oxide-generated cGMP4,5, nitric oxide signalling is often depressed by heart disease6. PDEs controlling natriuretic-peptide-coupled cGMP remain uncertain. Here we show that cGMP-selective PDE9A (refs 7, 8) is expressed in the mammalian heart, including humans, and is upregulated by hypertrophy and cardiac failure. PDE9A regulates natriuretic-peptide- rather than nitric-oxide-stimulated cGMP in heart myocytes and muscle, and its genetic or selective pharmacological inhibition protects against pathological responses to neurohormones, and sustained pressure-overload stress. PDE9A inhibition reverses pre-established heart disease independent of nitric oxide synthase (NOS) activity, whereas PDE5A inhibition requires active NOS. Transcription factor activation and phosphoproteome analyses of myocytes with each PDE selectively inhibited reveals substantial differential targeting, with phosphorylation changes from PDE5A inhibition being more sensitive to NOS activation. Thus, unlike PDE5A, PDE9A can regulate cGMP signalling independent of the nitric oxide pathway, and its role in stress-induced heart disease suggests potential as a therapeutic target.
We thank students R. D. Wardlow and X. Hu for their assistance with some of the assays and studies. This research was supported by: the National Institutes of Health (NIH) (HL-119012, HL-089297, HL-07227), Fondation Leducq TransAtlantic Network of Excellence, The Peter Belfer Foundation, Abraham and Virginia Weiss Professorship (D.A.K.); HL-093432 (E.T.), American Heart Association (D.I.L.) and Max Kade Fellowship of the Austrian Academy of Sciences (P.P.R). Procurement of human heart tissue was enabled by grants from the National Institutes of Health (HL089847 and HL105993) to K.B.M. N.H. and W.J.P. were supported by the European Commission FP7 project 2010 Health (MEDIA; 261409). R.H. and J.E.V.E. were supported by The Johns Hopkins Innovation Proteomics Center in Heart Failure (NHLBI-HV-10-05 (2) and HHSN268201000032C). W.R.D. was supported by NIH grant HL68891 and the Totman Trust for Biomedical Research. We thank Pfizer and in particular C. Schmidt and R. Kleiman for providing the Pde9a−/− mouse and PF-04449613, and L. Jaffe at the University of Connecticut Health Center for providing the PDE9A antibody.
Extended data figures
Extended data tables
This file contains Supplementary Tables 1-3.