Submitted to: Gordon Research Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: January 4, 2004
Publication Date: January 20, 2004
Citation: Heidari, M., Zuerner, R.L., Alt, D.P., Neill, J.D. 2004. Sage analysis of bovine macrophages: identification of genes targeted for immune suppression by digital dermatitis spirochetes. Gordon Research Conference Proceedings. p. 20. Technical Abstract: Papillomatous digital dermatitis (PDD) is a leading cause of lameness in dairy cattle. Microbiological and histological analyses suggest several different bacterial types are associated with PDD. Spirochetes related to Treponema phagedenis are a consistent feature of PDD lesions. These spirochetes are often found at the leading edge of PDD lesions, and likely play an important role in the progression of the infection. To investigate the differential gene expression in PDD host cells, serial analysis of gene expression (SAGE) was utilized. SAGE is a powerful global gene expression profiling technique used for comprehensive gene discovery and quantitative gene expression. Bovine macrophages (BoMac) were stimulated with whole cell-lysates (WCL) from a T. phagedenis-like bacterium recently isolated from PDD lesions. RNA extracted from BoMac cells was used to construct SAGE libraries consisting of short sequence tags. The sequences of approximately 50,000 gene tags from each library were determined. Comparison of data obtained from non-stimulated and stimulated cells showed that the bacterial products induced a series of changes in gene expression, including many genes related to cell division, energy metabolism, protein synthesis, and stabilization of the extracellular matrix. Current studies are focused characterizing differential expression of several immune response genes that suggests that bacterial constituents from PDD-spirochetes suppress the host response to infection.