Our lab studies the molecular and cellular biology of prion diseases with the goal to develop therapeutic and prophylactic anti-prion strategies. Our lab is one of very few labs worldwide that covers the full spectrum of prion research, from in vitro platforms to cell culture and small and large animal models. Our unit can house up to 1,800 prion-infected rodents, has immunohistochemistry, confocal microscopy, single-cell RNASeq and spatial transcriptomics equipment in prion containment labs. We use various transgenic mouse lines for propagating prions of different species, knock-in mice that recapitulate CWD pathogenesis as found in the cervid host (pioneered by the Gilch lab) and have access to an in-house reindeer facility.
Prions are atypical infectious agents that cause strictly fatal neurodegenerative diseases, including Creutzfeldt-Jakob disease (CJD) in humans, scrapie in sheep, bovine spongiform encephalopathy (BSE) in cattle, and chronic wasting disease (CWD) in cervids. Prion diseases are prototypical conformational or protein misfolding disorders, caused by misfolding of the normal cellular prion protein (PrPC) into its infectious and pathologic isoform PrPSc. A lot of our current research studies chronic wasting disease (CWD), a highly contagious prion disease in free-ranging and captive cervids that is on the rise in the U.S. and Canada. There are many negative effects CWD has for cervid populations and certain sectors of Canadian economies. It is therefore crucial to establish strategies that facilitate an effective containment of CWD. Active vaccination would be such an approach but seems hampered by the apparent inability of the immune system to sense and counter-act prion diseases. Our group has established a strong research portfolio around CWD vaccine development that is at the international forefront. Ongoing research will define the correlates of protection for our vaccine candidates to develop vaccines that protect the animal population while reducing shedding of CWD prions into the environment. While this has been challenging to address in the past due to the lack of appropriate and affordable animal models, we now have knock-in mouse models that reflect CWD pathogenesis in cervids. We have also entered several collaborative vaccination-CWD challenge trials in deer and elk. The vaccination strategy used here has two significant additive effects. It has the potential to improve individual survival, which will hopefully translate into population effects. It also reduces prion shedding, likely translating into reduction of CWD prions in the environment in the long term.
We are also a founding member of the Canadian German CWD macaque consortium that studies the zoonotic potential of CWD by inoculation into Cynomolgus macaques since 2008. Our laboratory passaged macaque CWD into various rodent hosts, providing the first experimental evidence that CWD can orally infect old-world monkeys, considered a relevant non-human primate model.
The long-term goal of our research program is to study the molecular biology of prion infections to develop therapeutic and prophylactic anti-prion strategies. For chronic wasting disease specifically, we are developing CWD vaccines for farmed and free-ranging cervids that reduce mortality and release of CWD prions into the environment. We are also studying the zoonotic potential of CWD.
Our group has provided a solid proof-of-concept that vaccines targeting PrPC overcome tolerance and are effective and safe. We have also entered vaccination-CWD challenge trials in deer and elk (Colorado State University and Wyoming Game & Fish Department). Over the next years, our aims are (1) to establish that vaccines reduce lateral prion transmission, (2) to validate oral vaccine platforms in mouse and cervid studies, and (3) to define the molecular determinants of protection using single-cell transcriptomics for tailoring the most successful vaccines.
Our work resulted in a comprehensive mechanistic description of the roles of autophagy in prion infection. We showed that induction of autophagy induces prion clearance and impacts exosomal prion release. This work defined induction of autophagy as an anti-prion strategy. We also showed that autophagy can have contrasting functions in prion replication. These findings demonstrate that prions use cellular machineries to benefit propagation in certain cell types, whereas other cell types employ the same machinery as a defense mechanism.
We hypothesize that prion infection is influenced by proteostasis mechanisms that positively or negatively affect prion propagation. We propose that prion replication must find the right balance within this scenario. Our goal is to define the molecular mechanisms of how autophagy and Hsp110 molecular chaperones act as cellular modifiers of prion infection. We manipulate these pathways in cell and mouse models of prion infection, and test whether targeting both pathways results in additive anti-prion effects.
Using cynomolgus macaques, we explored the zoonotic potential of CWD. Sensitive prion amplification assays revealed low levels of prions in macaque tissues. Inoculation of transgenic mice and bank voles with macaque tissues induced a full-blown prion disease upon serial transmission. One interpretation of these findings is that CWD prions retain infectivity across species and that primate infection may manifest atypically. Our results challenge conclusions that minimize the zoonotic risk of CWD and underscore the need for continued surveillance.
RT-QuIC, PMCA, and Western Blots are the foundational methodologies defining the prion field, allowing us to quantify and qualify various key properties of prion proteins.
To get a bigger picture of gene and protein interactions from pathogenesis to treatment, we employ transcriptomics, scRNAseq (10x), spatial transcriptomics, and proteomics.
Our lab employs the use of animal models as well, namely WT Transgenic and KI Mice, Bank Voles, Reindeer, White Tailed Deer, Mule Deer, and Rocky Mountain Elk.
We investigate prion biochemistry using cell line models (Cad-5, RK-13, N2A) gene editing (Lentivirus and CRISPR) and primary cell culture (fibroblasts, and IPSCs).
Vaccine development projects involve both production of recombinant prion proteins (MACS) and encapsulation (PLGA Nanoparticles), but also validation of immune response (ELISA, ELISpot).
