RNA sequencing of Mycoplasma bovis infecting bovine mammary epithelial cells and bovine mononuclear cells.

Abstract

Importance: Mycoplasma bovis is the major pathogen of bovine mycoplasmosis, such as mastitis, pneumonia, otitis media, and arthritis. Understanding the pathophysiology of mycoplasmal infections from the pathogen-side is as important as elucidating the host-side effects; however, few studies have focused on the variations in the expression of M. bovis genes.

Objective: In this study, we performed RNA sequencing of M. bovis infecting bovine mammary epithelial cells (bMECs) and mononuclear cells (MNCs) to elucidate pathogen-side factors involved in the pathophysiology of M. bovis mastitis.

Methods: M. bovis was cocultured with bMEC and MNC using a transwell system, and total RNA was extracted for RNA sequencing analysis.

Results: We identified 162 differentially expressed genes (DEGs), 104 upregulated and 58 downregulated, in M. bovis infecting bMEC, whereas 220 DEGs, 154 upregulated and 66 downregulated, in M. bovis infecting MNC. Enrichment analysis of upregulated DEGs in M. bovis infecting bMEC revealed multiple pathways with overlapping genes involved in lipid metabolism. The expression of six virulence genes were significantly upregulated in M. bovis infecting bMEC and MNC, whereas the expression of three virulence genes were significantly downregulated in M. bovis infecting MNC.

Conclusions and relevance: Our findings indicate that M. bovis exhibits infecting cell-specific gene expression, and its virulence varies with the infecting cell type.