PSMG4 and chronic obstructive pulmonary disease: PSMG4 was involved in pathways related to “Statin action on the PI3K/Akt pathway in COPD”, “DNA damage_Classical NHEJ mechanism of DSBs repair”, “Folic acid metabolism”, “Possible regulation of HSF-1/chaperone pathway in Huntington's disease”, and “Development_Negative regulation of WNT/Beta-catenin signaling in the nucleus” (Figure 9; Supplementary Table S4).