3.3 GO and KEGG enrichment
The GO was used to identify key biological functions corresponding to 1 of 3 term categories, namely, biological process, cellular component, and molecular function. Results showed that the most significant GO terms in each term category for 173 significant DEGs were ”antigen processing and presentation of peptide or polysaccharide antigen via MHC class II”, ”MHC class II protein complex”, and ”MHC class II receptor activity” (Table 2, Fig. 2A). Furthermore, the identified significantly enriched KEGG pathways of significant DEGs were demonstrated to be about infection, inflammation, and immune response (Table 2, Fig. 2B). Among them, virus infection, antigen processing and presentation, and B cell receptor were identified as those that might play an important role in the pathogenesis of BPD.
Similarly, the results of GSE32472 were analyzed by Pietrzyk et al. suggested that the signaling pathway of the hematopoietic cell lineage, allograft rejection, asthma, intestinal immune network for IgA production, and cell adhesion molecules (CAMs) were also involved in BPD (Pietrzyk et al., 2013). Moreover, the hematopoietic cell lineage signaling pathway could be obtained in all 3 measurements in their study. Regarding the results of GSE125873 which were analyzed by Ryan et al., they also found the signaling pathway of CAMs, phagosome, systemic lupus erythematosus, and leishmaniasis. In addition, they also obtained the processes of ”antigen processing and presentation of exogenous peptide antigen via MHC class II”, ”antigen processing and presentation of peptide or polysaccharide antigen via MHC class II” and ”MHC class II receptor activity” in the terms of the GO-BP category (Ryan et al., 2019).