Phosphodiesterase isoform (PDE (for the family), specific isoforms are abbreviated as PDE1, PDE2, etc.)

Phosphodiesterase isoforms are a large superfamily of enzymes that catalyze the hydrolysis of cyclic nucleotides, primarily cAMP and cGMP, thus terminating their signaling pathways[1][7][5]. There are 11 mammalian phosphodiesterase families (PDE1–PDE11), each encoded by different genes and generating multiple isoforms through alternative splicing, with variations in tissue distribution, regulatory mechanisms, and substrate specificity[1][5][7]. Some isoforms are selective for cAMP (e.g., PDE4, PDE7, PDE8), others for cGMP (e.g., PDE5, PDE6, PDE9), and some are dual-specificity (e.g., PDE1, PDE2, PDE3, PDE10, PDE11)[1][5][7]. They play essential roles in the regulation of key physiological processes such as vascular tone, cardiac contractility, neural signaling, immune response, and inflammation. Because of their central role in controlling intracellular second messengers, specific PDE isoforms are drug targets for various clinical indications, including cardiovascular, respiratory, neuropsychiatric, and inflammatory diseases[2][4][6]. Drug development focuses on selective inhibition of individual isoforms to maximize therapeutic effects and limit side effects; however, adverse drug reactions remain a key challenge, especially due to the wide tissue distribution and functional redundancy among PDEs[4][2][5].

Other names

PhosphodiesterasesPDEsCyclic nucleotide phosphodiesterases

Inhibition of cAMP-specific phosphodiesterases increases intracellular cAMP, leading to smooth muscle relaxation and anti-inflammatory effects Inhibition of cGMP-specific phosphodiesterases increases cGMP, enhancing vasodilation and/or affecting retinal signaling Dual inhibitors (e.g., PDE3) alter the balance of cAMP/cGMP signaling, impacting cardiac contractility, platelet aggregation, and metabolic regulation