Comparison of mRNA expression levels of selected genes in the brain stem of cattle naturally infected with classical and atypical BSE

Since 2004 cases of atypical bovine spongiform encephalopathy (BSE) in older cattle are recorded on the basis of aberrant glycoprofiles of prion protein resistant to proteolysis (PrPres). The nature of those types of PrPres is still not fully understood but the epidemiological data indicate that their occurrence is rare. Hitherto, most BSE cases were studied on the basis of the features of pathological form of prion protein (PrPSc) or lesions observed in the gray matter of the brain. Here we propose the gene expression profiling as a method to characterize and distinguish BSE types. Thus, the aim of the study was to compare the activity of some genes which are known to play a role in the pathogenesis of transmissible spongiform encephalopathies (TSEs). Significant differences in the expression level of the selected genes in the brain stem were observed for 7 out of 11 genes tested when the results for BSE affected and healthy control animals were compared. Significant up-regulation of caspase 3, Bax and 14-3-3 protein encoding genes was apparent in the obex of all BSE affected cattle regardless of the prion type. Significant and unique to BSE H-type up-regulation was detected in prion and SOD1 genes, while BSE C-type was characterized by higher Bcl-2 and Fyn gene expression levels in respect to other BSE types and control animals. Different gene expression profiles of bovine brains infected with classical and atypical BSE indicate possible different pathogenesis or origin of the disease.

Research Highlights
► All BSE affected cattle regardless of the prion type were characterized by significant up-regulation of caspase 3, Bax and 14-3-3 protein encoding genes in the obex region.
► BSE type-dependent, significant differences in the gene expression were observed for BSE H-type and BSE C-type.
► Significant and unique to BSE H-type up-regulation was detected in prion and SOD1 genes.
► BSE C-type was characterized by higher Bcl-2 and Fyn gene expression levels.
► Differences in the gene expression profiles of bovine brains infected with classical and atypical BSE suggest possible different pathogenesis or origin of the disease.