PoP Projects

The zebrafish is recognized internationally an inexpensive model of neurodegenerative disease, as the genes of zebrafish can be readily manipulated within individual cell types, allowing researchers to create CWD prion-infectible fish. To cross the species barrier (as mice are not infectible with CWD prions from deer), the team's engineering of zebrafish includes disrupting the fish's PrP-C gene and replacing it with the PrP-C gene from deer. They will also manipulate various portions of the deer PrP gene and investigate how these mutations affect the functions of PrP in neurodegenerative disease. This basic understanding is critical to design of effective intervention and monitoring in prion disease progression. Prion-infectible fish will be used to monitor for the presence of prions and to as an efficient primary screen for therapeutic drugs. The end goals are to identify targets of prion disease treatment and environmental monitoring.

The key to managing CWD in wild and farmed deer is a better understanding of the risk factors in disease transmission and progression. One way to accomplish this is by identifying genes for CWD susceptibility; another is to study genetic variation in naturally infected and uninfected wild deer using similar methods that are being used to study the genetics of human disease. This project aims to assess the feasibility of using the "association mapping" approach that tests for correlations between marker alleles and disease status to identify disease-susceptibility genes. They will determine how the deer genome is organized by quantifying linkage disequilibrium, and then they will conduct a pilot experiment to test for association between genetic markers and CWD prevalence in matched case/control wild deer using a panel of several hundred microsatellites of predicted chromosomal location.

This project aims to detect and quantify PrPC expression in antler velvet at different stages of development and in the innervations trigeminal nerve, brain stem nuclei and ganglia. The hypothesis is that PrPC is expressed in high levels in the densely innervated and highly active antler velvet, in correlation with the developmental stage of antlers and increases towards the terminal stage of antler development. In CWD infected animals this would result in high conversion rates of PrPC to PrPCWD and subsequent high concentrations of PrPCWD in antler velvet before shredding. If the hypothesis is verified, the team plans to look at topography and levels of PrPCWD expression in infected animals in a second project, in an effort to address the larger hypothesis regarding the environmental accumulation of PrPCWD and transmission of CWD in the deer population. The results could contribute to an improved understanding of the pathobiology of CWD, the transmission within deer populations, and ultimately t o a basis for controlling CWD in farmed and wildlife deer in Alberta.

This project intends to synthesize novel organic molecules that are explicitly designed to attach tightly to infectious prion particles by taking advantage of their "multimeric" structure. These molecules could have several important uses. First, they could aid in the structural analysis of the infectious form of the prion protein. If the organic binders stabilized one particular type of cluster, it might lend itself to the traditional tools of structural biology. Second, these molecules could be used for the detection of infectious prion protein if a fluorescent "reporter" group is also attached. Finally, tightly binding compounds may inhibit the transmission of prion diseases by preventing interaction between the infectious particles and normally folded prion protein. Such molecules could serve as lead compounds for the eventual development of therapeutic drugs to treat prion diseases.

“Functional interactions between prion proteins and NMDA receptors—a role in prion pathophysiology?”

Building on preliminary date, this project plans to test the hypothesis that the conversion of native PrP by the infectious form of PrP leads to an unsilencing of NR2D containing receptors, thus raising the susceptibility of glutamate toxicity, and cell death. To test this, they will use a combination of complimentary experimental techniques, including functional studies in primary hippocampal cultures and brain slices, electrophysiology, molecular biology, and the use of PrP and NR2D knockout mice, all of which are established in the principal investigator's laboratory. The team anticipates findings that will provide novel insights into the function of PrP in both health and disease, and may yield novel strategies for interfering with neuronal loss during prion disease.