Fig. 2

Functional enrichment analysis of COPD-associated DEGs emphasizes the mitochondrial alternations. a Volcano plots for COPD-associated DEGs in six bulk RNA-seq datasets of human lung tissues from COPD patients and control individuals with the number of up- and down-regulated DEGs of each dataset displayed in the plot. One dot represents a gene. Blue dots represent down-regulated DEGs. Red dots represent up-regulated DEGs. Gray dots represent genes showed no significant differential expression. b GSEA analysis of COPD-associated DEGs in six bulk RNA-seq datasets. The activated pathways were arranged in the left column and the suppressed ones were in the right column. c Functional enrichment analysis showing molecular function (green), cell component (red), and biological process (blue) in GO categories of COPD-associated DEGs in six bulk RNA-seq datasets