Phosphodiesterases (PDEs) are a class of enzymes that regulate cellular signaling by hydrolyzing cyclic nucleotides (such as cAMP and cGMP) to reduce their levels. The PDE family includes multiple subtypes (PDE1-PDE11), each with specificity in cellular or tissue localization and expression. PDEs play important roles in the heart, lungs, brain, and other tissues, participating in the regulation of cardiovascular function, neurotransmission, immune responses, and other biological processes. Gene expression is regulated by various factors, and mutations or abnormal expression are associated with various diseases, including cardiovascular diseases, neurodegenerative disorders, and inflammatory diseases.