Identification of key genes and signaling pathways in comparative transcriptome analysis of bovine mammary epithelial cells challenged with Escherichia coli

Substantial evidence demonstrates that the identification of pathogens is of major importance in order tocorrect actions, prevent transmission to other cows, reduce the risk of appearance of chronic infections, andaid to reduce inappropriate use of antibiotics, antimicrobial resistance, and cost of treatment. Escherichia coli(E. coli) is one of the most prevalent Gram-negative pathogens known that causes mammary gland infectionsin dairy cattle and may greatly influence animal welfare and milk composition/quality negatively. Mammaryepithelial cells (MEC) act as sentinels to bacterial intrusion by producing mediators of inflammation andlocal defense. In this study, a public microarray dataset GSE۴۷۵۹۹ was used to explore the differentiallyexpressed genes (DEGs) from ۱۶ mammary epithelial cell samples containing ۸ samples infected with E. coliand ۸ samples as control. Differential gene expression analysis between infected and control samples wasperformed identifying ۱۴۷ DE genes based on fold change > ±۰.۰۵ and false discovery rate <۰.۰۵, of which۱۳ were underexpressed and ۱۳۴ genes were overexpressed in the infected samples compared to controlsamples. Among these genes, five genes—ISG۱۵, CCL۲, TLR۲, MX۱, and JAK۲—were identified as thehub genes (highly connected genes), which were subjected to protein-protein interaction (PPI) network.Moreover, functional annotation and enrichment analysis identified ۲۷, ۹, and ۳ GO terms related toinflammatory and immune responses in the biological process, molecular function, and cellular componentcategories, respectively. KEGG pathway significant enrichment analysis revealed that the DEGs participatedin ۴۴ pathways which are known to be enriched in TNF signaling pathway, IL-۱۷ signaling pathway, Tolllikereceptor signaling pathway, and chemokine signaling pathway. Therefore, the identification of diseasecausinggenes and genetic mechanisms related to immune or inflammatory responses helps to improvediagnosis, prognosis, and monitoring of responses to therapy.

کلیدواژه ها:

Differentially expressed genes ، Mammary epithelial cells ، Pathway analysis ، Bovine