Human phosphodiesterase-4 (PDE4)

Human phosphodiesterase-4 (PDE4) is an intracellular, non-receptor enzyme that hydrolyzes the second messenger cAMP to its inactive form and plays a central role in controlling multiple cellular signaling processes. There are four genes encoding the main isoforms (PDE4A, PDE4B, PDE4C, PDE4D), each with several variants created through alternative splicing, differing in tissue distribution and subcellular localization. PDE4 is predominantly expressed in immune, epithelial, and central nervous system cells, where it serves as a key regulator of inflammation and immune responses. Dysregulation of PDE4 activity has been implicated in various inflammatory, autoimmune, and neurological disorders, making it a validated drug target. Several orally and topically administered PDE4 inhibitors, including Roflumilast, Apremilast, and Crisaborole, are approved for the treatment of persistent inflammatory and autoimmune diseases. While effective, current inhibitors are limited by gastrointestinal and neuropsychiatric side effects, and ongoing research focuses on improving safety, isoform selectivity, and expanding therapeutic indications.

Other names

Phosphodiesterase 4PDE-4cAMP-specific 3',5'-cyclic phosphodiesterase 4PDE4APDE4BPDE4CPDE4D

Inhibition of PDE4 catalytic activity, leading to increased intracellular cAMP levels; Suppression of proinflammatory cytokine production and inflammatory cell activity through cAMP-mediated signaling; Modulation of gene and protein expression downstream of the cAMP pathway