A new study suggests that gene expression profiling may allow researchers to track the progression of bovine spongiform encephalopathy (BSE) in cattle and ultimately predict their infectious status.
The researchers from the Veterinary Laboratories Agency, Woodham Lane, New Haw, Surrey, United Kingdom and Ludwig-Maximilians-University Munich, Germany detail their findings in the September 2009 issue of the Journal of Virology.
Prion diseases are transmissible, and inevitably fatal, neurodegenerative disorders that are responsible for BSE in cattle, Creutzfeldt-Jakob disease (CJD) in humans, and scrapie in sheep and goats. The first cases of BSE were reported in the United Kingdom in 1986 and reached epidemic proportions by 1992 at which point up to 185,000 cattle had succumbed to the disease. Contaminated meat and bone meal, common dietary supplements, are believed to be the cause of oral infection in cattle and BSE is considered to be the origin of the human disease variant of which there have been approximately 200 cases worldwide. Current research suggests that an abnormality of the cellular prion protein is essential to the infectivity of prion disease, indicating a correlation between BSE pathogenesis and gene expression.
In the study brain tissue samples were collected from cattle orally infected with BSE at varying time points following postinfection and monitored for changes in gene expression. Researchers found that 114 genes were differentially regulated over the course of infection, many of which encode proteins involved in functions such as immune response, stress response and cell adhesion. The largest number of differentially regulated genes was detected at 21 months postinfection indicating many pathogenic processes in the animal brain prior to detection of BSE in the central nervous system.
"Gene expression profiling in the BSE time course study revealed a broad correlation between the expression of genes and the progression of BSE," say the researchers. "Evidence is presented to suggest that it is possible to predict the infectious status of animals using the expression profiles from this study."
(Y. Tang, W. Xiang, S.A.C. Hawkins, H.A. Kretzschmar, O. Windl. 2009. Transcriptional changes in the brains of cattle orally infected with the bovine spongiform encephalopathy agent precede detection of infectivity. Journal of Virology, 83. 18: 9464-9473.)
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