PDE7A and metabolic disease: Phosphodiesterase7 (PDE7) regulates cAMP-PKA signalingand playsa crucial role in immune function, neuroprotection, and inflammation.Dysregulated PDE7 activity is linked to neurodegenerative, autoimmune,and metabolic disorders, making it a promising therapeutic target.Recent advancements in PDE7 inhibitors, particularly pyrimidinone-basedcompounds, have shown high selectivity and potent biological effects.Beyond therapeutics, radiolabeled PDE7 inhibitors offer potentialfor PET imaging, enabling noninvasive disease monitoring and treatmentassessment.