Molecular Mechanisms and Pathological Effects of Strain Specificity in Prion Infection

The prion proteins are the basis of novel infectious, neurodegenerating diseases. Under normal conditions, most organisms produce prion proteins (PrP). The normal PrP contains α 1-23 N-terminal segment which is responsible for piloting the protein from the site of synthesis through the Golgi to the plasma membrane. In disease conditions, PrP loses its secondary structure reducing its α-helical contents and leading to a protein that has a higher level of the β-pleated sheath. This change can be detected easily through Infrared spectroscopy. This misfolding could be due to mutation in the gene encoding the protein, and the mRNA. The kiss of the abnormal prion to the normal has been thought to be the key signature in the pathology of prion disease. Prion disease infection is strain-dependent, manifestation and symptoms in one species differ from another. Infectivity of the prion usually is more prone in similar species and less prone between inter-species perhaps the difference in the sequence of amino acids, replication environment, recognition elements, size of fragments, mutation, level of glycosylation, and NAD+ depletion account for this. There are currently no therapies that effectively treat the underlying causes of prion infection, although there are treatments that can alleviate some of its symptoms, and delay the stacking of PrPres. Also, novel disease-modifying strategies/therapeutic approaches that are aimed at down-regulating expression and PrPsen knocking out are promising. Chitosan serves as an efficient vehicle for crossing the blood-brain barrier. This review discusses the prion’s nature, strain-specific modes of infection, and possible therapeutic approaches.