Targeting PDE4 has been verified as an effective therapeutic strategy for inflammatory conditions, including asthma, chronic obstructive pulmonary disease (COPD), psoriasis, atopic dermatitis (AD), inflammatory bowel diseases (IBD), rheumatic arthritis (RA), lupus, and neuroinflammation (as shown in Figure 1). The gene discussed is PDE4A; the disease is chronic obstructive pulmonary disease.