Phosphodiesterase (PDE) (PDE)

Phosphodiesterases (PDEs) are a superfamily of enzymes responsible for the hydrolysis of the phosphodiester bond in the second messenger molecules cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). By regulating the levels and localization of these cyclic nucleotides, PDEs play a critical role in signal transduction pathways that govern various physiological processes, including smooth muscle contraction, platelet aggregation, and immune cell activation [1, 6]. There are 11 known families of PDEs (PDE1–PDE11), each with distinct substrate specificities and tissue distributions [7, 10]. Caffeine acts as a non-selective PDE inhibitor, though its primary physiological effects at dietary doses are often attributed to adenosine receptor antagonism; however, at higher concentrations, it effectively inhibits PDEs, leading to increased cAMP levels and subsequent bronchodilation and cardiac stimulation [1, 2, 3]. Dysregulation of PDE activity is associated with numerous pathological states, including cardiovascular disease, inflammatory disorders, and neurological conditions [8, 16]. Consequently, PDE inhibitors have been developed as therapeutic agents for a wide range of indications, from respiratory diseases like asthma to vascular conditions like pulmonary hypertension [1, 15]. While non-selective inhibitors like caffeine and theophylline were among the first used, modern drug discovery focuses on isoform-selective inhibitors to minimize off-target effects and improve safety profiles [15, 17].

Other names

Cyclic nucleotide phosphodiesterase3',5'-cyclic-nucleotide phosphodiesterasePDE familyPhosphodiesterase enzyme

Inhibition of the hydrolysis of cyclic adenosine monophosphate (cAMP) and/or cyclic guanosine monophosphate (cGMP) into their inactive 5'-monophosphate forms, thereby increasing intracellular concentrations of these second messengers and prolonging their signaling effects.