Distribution of cellular prion protein in normal human cerebral cortex--does it have relevance to Creutzfeldt-Jakob disease?

Abstract

Creutzfeldt-Jakob disease and bovine spongiform encephalopathy are the best known forms of prion diseases. A basis for their pathogenesis is the transformation of normal prion protein to abnormal prion protein. This would mean that either loss of normal function or a gain of a toxic function of the prion protein would play a major role. Since the prime target for Creutzfeldt-Jakob disease in humans is the neocortex, and the intracortical distribution of the destructive process in prion diseases appears not to be haphazard, it may be that a clear cortical study of normal prion protein production in the premorbid human neocortex might contribute to insight in the pathogenesis of prion diseases. As no such study is available, we performed a detailed study in normal human cortex using immunohistochemistry for prion protein, in both frozen and vibratomised tissue, and in situ hybridisation for prion protein mRNA. We have found normal prion protein production mainly in the upper cortical neurons in neocortex and Purkinje cells in the cerebellum. This finding implicates that normal prion protein is more important as an anti-apoptotic signal in disease than abnormal prion protein is as a toxic substance.