Identification of the Potential chi-miR-148a-5p-PTGS2 Regulatory Axis Mediating TNF and IL-17 Signaling Pathways in Caprine Bronchial Epithelial Cells Challenged with Klebsiella Pneumoniae.

Klebsiella pneumoniae (K. pneumoniae) belongs to the genus Klebsiella of the Enterobacteriaceae family. In goats, K. pneumoniae infection can result in respiratory diseases such as pneumonia and bronchopneumonia. In this study, caprine bronchial epithelial cells were infected with K. pneumoniae, and multi-omics integration analysis was conducted to investigate the immune defense mechanisms triggered by the infection. Enrichment analysis of differentially expressed genes (DEGs) using the KEGG database revealed that immune-related signaling pathways involving TNF and IL-17 were among the top 20 most enriched. Based on the TNF and IL-17 signaling pathways, ten immune pathway-related genes, including CCL20, CXCL1, TRAF4, FOS, IL6, PTGS2, TNF, CXCL8, TNFAIP3, and JUN, were selected for RT-qPCR validation. In addition, four miRNAs targeting genes involved in the above pathways, namely chi-miR-148a-5p, miR-1285-z, miR-16-x, and miR-6119-x, were verified by RT-qPCR. The expression trends of chi-miR-148a-5p and miR-1285-z were consistent with microRNA sequencing results. Furthermore, gain- and loss-of-function experiments indicated that chi-miR-148a-5p may target TNF and PTGS2, while miR-1285-z may target NFKBIZ, with CSF2 predicted as a potential target. This study suggests that chi-miR-148a-5p and miR-1285-z may participate in the TNF and IL-17 signaling pathways by regulating their predicted target genes. Moreover, the TNF and IL-17 signaling pathways are among the most highly enriched immune-related pathways involved in the innate immune response of caprine bronchial epithelial cells. This study provides insights into the molecular mechanisms underlying immune responses in goats infected with K. pneumoniae.