Elucidating the cellular mechanisms of prion propagation and clearance for devising new targets for intervention in prion disease There are an increasing number of neurodegenerative disorders which result from the aggregation of misfolded proteins and which share patho-physiological mechanisms. Prion diseases are the prototypical protein misfolding diseases, and their pathogenesis is associated solely with aberrant misfolding of a single cellular protein (PrPc). Prion diseases are unique in this group as they are infectious disorders found in man and animals. Besides sporadic or genetic manifestation, they can be acquired by infection and transmitted between species, resulting in endemic or epidemic scenarios (e.g. BSE/vCJD and CWD). They can be controlled, but eradication is impossible. Therefore, it is mandatory to understand the molecular and cellular requirements for propagation and transmission of prions in order to device rational strategies for controlling these events. Advances in understanding prion patho-physiology will have major implications for other protein misfolding diseases, as it may help elucidate common cellular mechanisms. Such understanding is of fundamental scientific importance as neurodegenerative diseases represent one of the biggest health problems in our aging society, and uncovering molecular mechanisms of general validity is fundamental for the identification of new targets and development of rational therapies. The long-term goal of our group is to develop therapeutic and prophylactic anti-prion strategies. The overall objective we have is to study the cellular and molecular biology of prion infections and to use gained understanding for delineating novel targets for intervention. We have focused our attempts on two main strategies. One is the endogenous cellular clearance capacity for prions, the other one is to target the cellular isoform PrPc, which is a prerequisite for prion conversion and execution of neurodegeneration. It is our central hypothesis that it is feasible to interfere in prion propagation by increasing the cellular clearance for prions. Work in Aim 1 will substantiate our finding that prion clearance can be enhanced by compound-induced induction of autophagy, a basic cellular program for degradation and recycling. The proposed work intends to better understand the underlying molecular mechanisms and to validate the therapeutic and translational potential of this finding in vivo. Work in Aim 2 and 3 addresses cellular modifiers of prion formation. We have found that a basal level of autophagy is needed for establishing prion infection and we propose that autophagy represents the biological equivalent for the postulated disaggregase function in mammalian prion/prion-like biology. Our goal is to prove this at the cellular and molecular level. The rational for work in Aim 3 is that protein quality control mechanisms in the secretory pathway can directly influence prion conversion by determining on the quality of conversion substrates. We want to manipulate this by over-expressing folding and sorting proteins, in order to show that this represents a novel pathway counteracting prion propagation. Overall, our studies will provide mechanistic insights into basic cellular and molecular mechanisms which are relevant for neurodegenerative diseases and will result in novel targets for rational therapy against prion diseases and protein misfolding disorders.

Public Health Relevance

Understanding how prions reproduce at the cellular level is necessary for developing rational strategies to fight against prion diseases. We are using existing cellular programs which we manipulate in a way that this either disfavors the formations of prions or induces their degradation. Our work provides mechanistic insights into basic mechanisms which are relevant for neurodegenerative diseases and will result in novel targets for rational therapy against prion diseases and protein misfolding disorders.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS076853-02
Application #
8465922
Study Section
Cellular and Molecular Biology of Neurodegeneration Study Section (CMND)
Program Officer
Wong, May
Project Start
2012-06-01
Project End
2017-05-31
Budget Start
2013-06-01
Budget End
2014-05-31
Support Year
2
Fiscal Year
2013
Total Cost
$298,698
Indirect Cost
$87,604
Name
University of Wyoming
Department
Veterinary Sciences
Type
Schools of Earth Sciences/Natur
DUNS #
069690956
City
Laramie
State
WY
Country
United States
Zip Code
82071
Engelke, Anna D; Gonsberg, Anika; Thapa, Simrika et al. (2018) Dimerization of the cellular prion protein inhibits propagation of scrapie prions. J Biol Chem 293:8020-8031
Taguchi, Yuzuru; Lu, Li; Marrero-Winkens, Cristobal et al. (2018) Correction: Disulfide-crosslink scanning reveals prion-induced conformational changes and prion strain-specific structures of the pathological prion protein PrPSc. J Biol Chem 293:14925
Thapa, Simrika; Abdulrahman, Basant; Abdelaziz, Dalia H et al. (2018) Overexpression of quality control proteins reduces prion conversion in prion-infected cells. J Biol Chem 293:16069-16082
Taguchi, Yuzuru; Lu, Li; Marrero-Winkens, Cristobal et al. (2018) Disulfide-crosslink scanning reveals prion-induced conformational changes and prion strain-specific structures of the pathological prion protein PrPSc. J Biol Chem 293:12730-12740
Abdulrahman, Basant A; Abdelaziz, Dalia H; Schatzl, Hermann M (2018) Autophagy regulates exosomal release of prions in neuronal cells. J Biol Chem 293:8956-8968
Abdulrahman, Basant A; Abdelaziz, Dalia; Thapa, Simrika et al. (2017) The celecoxib derivatives AR-12 and AR-14 induce autophagy and clear prion-infected cells from prions. Sci Rep 7:17565
Shim, Su Yeon; Karri, Srinivasarao; Law, Sampson et al. (2016) Prion infection impairs lysosomal degradation capacity by interfering with rab7 membrane attachment in neuronal cells. Sci Rep 6:21658
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Taguchi, Yuzuru; Schätzl, Hermann M (2014) Small-scale Subcellular Fractionation with Sucrose Step Gradient. Bio Protoc 4:
Taguchi, Yuzuru; Mistica, Arla M A; Kitamoto, Tetsuyuki et al. (2013) Critical significance of the region between Helix 1 and 2 for efficient dominant-negative inhibition by conversion-incompetent prion protein. PLoS Pathog 9:e1003466

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