Phosphodiesterase 3 and 4 (PDE3/4)

Phosphodiesterase 3 (PDE3) and Phosphodiesterase 4 (PDE4) are enzymes that catalyze the hydrolysis of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), which are critical second messengers in signal transduction (UniProt, 2024). In bronchial smooth muscle, PDE3 is a primary regulator of cAMP levels, and its inhibition leads to smooth muscle relaxation and bronchodilation (PubMed, PMID: 25134490). PDE4 is the major phosphodiesterase found in inflammatory cells, including neutrophils and macrophages, where it modulates the release of pro-inflammatory cytokines (StatPearls, 2023). The dual inhibition of PDE3 and PDE4 provides a synergistic therapeutic effect by combining potent bronchodilation with broad-spectrum anti-inflammatory activity (PubMed, PMID: 30131461). This dual-target approach is specifically utilized in the treatment of Chronic Obstructive Pulmonary Disease (COPD) and asthma to improve lung function and reduce exacerbations (ClinicalTrials.gov, 2024). Inhaled dual PDE3/4 inhibitors, such as ensifentrine, are designed to provide these benefits locally in the lungs while minimizing systemic adverse effects like nausea or tachycardia (PubMed, PMID: 37354566).

Other names

Phosphodiesterase III/IVDual PDE3/4Cyclic nucleotide phosphodiesterase 3 and 4PDE3 and PDE4

Dual inhibition of PDE3 and PDE4 enzymes increases intracellular concentrations of cAMP and cGMP in airway tissues, leading to protein kinase activation, reduced intracellular calcium, and subsequent relaxation of bronchial smooth muscle alongside the suppression of inflammatory mediator release from immune cells.