Screening of key genes involved in endometritis in cows and the regulatory role of CD83 in bovine endometrial epithelial cells.

Endometritis in dairy cows involves complex molecular regulatory mechanisms. Therefore, uncovering the molecular regulatory mechanisms of endometritis in dairy cows is crucial to understand its development, prevention, and treatment. This study aimed to screen and validate key genes associated with endometritis using transcriptome sequencing of blood samples and previously obtained metabolomic sequencing data. Based on gain-of-function and loss-of-function experiments on the gene, multiple techniques, including qRT-PCR, western blotting, detection of reactive oxygen species (ROS), measurement of mitochondrial membrane potential, EdU assay, flow cytometry, and CCK-8 assay were used to explore the function of the key gene in lipopolysaccharide (LPS)-stimulated bovine endometrial epithelial cells (BEECs). The results identified 536 differentially expressed genes (DEGs) between healthy cows and those with endometritis. These DEGs were significantly enriched in apoptosis and HIF-1 signaling pathways. Weighted gene co-expression network analysis of transcriptomic and metabolomic data identified CD83, CTNNAL1, LRRC25, and NR1H3 as potential key genes for endometritis in dairy cows, with CD83 being more significantly expressed in LPS-induced BEECs. Consequently, in vitro functional studies were performed on CD83. In overexpression experiments, downregulation of the expression of inflammatory markers interleukin (IL)-1β, IL-6, and IL-8 and reduced ROS release primarily indicated the role of CD83 in attenuating the inflammatory response of BEECs. Furthermore, overexpression of CD83 regulated the S/G2 phase transition of BEECs by affecting the mRNA and protein expression of proliferation marker genes, thereby promoting proliferation of BEECs. The increased EdU positivity and the cell proliferation rate further provided evidence for the promotion of cell proliferation after overexpression of CD83. Additionally, overexpression of CD83 attenuated LPS-stimulated mitochondrial damage in BEECs, as well as the downregulation of apoptosis marker gene expression. In contrast, knockdown of CD83 expression showed the opposite trend. In summary, CD83 attenuated the inflammatory response of BEECs, promoted their proliferation, and inhibited apoptosis. This study provided basic data for understanding the mechanisms of endometritis regulation at the gene level in dairy cows.