Pathogenesis of Chronic Wasting Disease in Transgenic Mice

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Project Summary/Abstract: This proposal employs a transgenic murine model of chronic wasting disease (CWD) to addresses sequential prion pathogenesis and the role of bone marrow in prion trafficking and neuroinvasion. The goals of the proposed studies are: (1) to characterize the multiple aspects of the pathogenesis of CWD in transgenic, cervid PrP-expressing (Tg[CerPrP]) mice by evaluation of sequential patterns of prion tissue tropism and neuropathology; and (2) to address the role of the bone marrow and its cellular progeny in the prion trafficking and pathogenesis through reciprocal transplantation studies. We will utilize a combination of single- and dual- labeling immunohistochemistry (IHC), western blotting (WB), and immunofluorescent confocal microscopy to detect accumulations of misfolded prion protein (PrPres) in conjunction with markers of neuropathology. To define the role of the bone marrow in prion trafficking and hematogenous neuroinvasion, we will use reciprocal adoptive bone marrow transfer to create two lineages of chimeric mice, which will have PrPc expression restricted to hematopoietic or non-hematopoietic compartments. We will characterize these mice through flow cytometry, and document sequential PrPres accumulation via IHC and WB. We expect that the CWD-infected mice will mimic naturally-infected cervids with respect to susceptibility, clinical disease, microscopic neuropathology, and PrPres distribution. We hypothesize/anticipate that CWD-infected mice will reveal novel, neuropathologic features of prion disease, including increased expression of markers of gliosis, neuronal loss and apoptosis adjacent to areas of PrPres accumulation. In the adoptive bone marrow transfer experiments, we hypothesize that marrow of CWD-infected Tg[CerPrP] mice will contain infectious prions, which will be associated with myeloid lineage cells. Additionally, we hypothesize that these cells will ferry PrPres to the brain as part of cell renewal and trafficking patterns. The results of these studies will enhance understanding of the mechanisms of prion disease-associated neuropathology, help inform anti-prion disease therapeutic strategies, and explore an under-investigated pathway of prion dissemination. Using the proposed experiments, my short- term objective will be to complete my PhD in the summer of 2010; my long term goal will then be to devote myself to a becoming a successful independent researcher. The key elements of the research career development plan designed to accomplish these goals include: (1) the establishment of an advisory/mentoring panel to help establish and monitor career performance milestones; (2) the identification and successful employment as an investigative pathologist in a research-focused department and institution with a well- established infectious disease and/or neurodegenerative program; (3) participation in extramural research training opportunities at established centers of prion and neurodegenerative disease; (4) submission of peer- reviewed manuscripts and extramural grant applications, and (5) extended responsibility and participation in laboratory, departmental, and national/international meetings and journal clubs.