The Role of Dipeptidyl Peptidase Inhibitors in Pulmonary Diseases

The dipeptidyl peptidase (DPP) family comprises enzymes with important metabolic and immunomodulatory properties. This narrative review summarizes recent clinical and experimental evidence on the role of DPP-1, DPP-4, DPP-9, and DPP-10 in pulmonary diseases. The strongest translational evidence currently supports DPP-1 inhibition in non-cystic fibrosis bronchiectasis, where brensocatib reduces exacerbations and prolongs time to first exacerbation, with additional DPP-1 inhibitors in development. By contrast, the roles of DPP-4, DPP-9, and DPP-10 are supported mainly by preclinical studies in pulmonary hypertension, acute lung injury (ALI)/acute respiratory distress syndrome (ARDS), pulmonary fibrosis, asthma, non-small cell lung cancer (NSCLC), and nonsteroidal anti-inflammatory drugs (NSAIDs)/aspirin-exacerbated respiratory disease. Across these models, DPP inhibition modulates inflammation, protease activation, epithelial- or endothelial-to- mesenchymal transition (EMT/ EndMT), extracellular matrix (ECM) remodeling, and related signaling pathways. Overall, DPP-targeted interventions are promising in pulmonary medicine, but broader clinical translation will require well-designed prospective trials.