scholarly journals Mechanisms of prion-induced neurodegeneration

Author(s):  
Paula Saá ◽  
David A. Harris ◽  
Larisa Cervenakova

Transmissible spongiform encephalopathies (TSEs), or prion diseases, are fatal neurodegenerative disorders characterised by long incubation period, short clinical duration, and transmissibility to susceptible species. Neuronal loss, spongiform changes, gliosis and the accumulation in the brain of the misfolded version of a membrane-bound cellular prion protein (PrPC), termed PrPTSE, are diagnostic markers of these diseases. Compelling evidence links protein misfolding and its accumulation with neurodegenerative changes. Accordingly, several mechanisms of prion-mediated neurotoxicity have been proposed. In this paper, we provide an overview of the recent knowledge on the mechanisms of neuropathogenesis, the neurotoxic PrP species and the possible therapeutic approaches to treat these devastating disorders.

Biomolecules ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 466
Author(s):  
Leonor Orge ◽  
Carla Lima ◽  
Carla Machado ◽  
Paula Tavares ◽  
Paula Mendonça ◽  
...  

Transmissible Spongiform Encephalopathies (TSEs) or prion diseases are a fatal group of infectious, inherited and spontaneous neurodegenerative diseases affecting human and animals. They are caused by the conversion of cellular prion protein (PrPC) into a misfolded pathological isoform (PrPSc or prion- proteinaceous infectious particle) that self-propagates by conformational conversion of PrPC. Yet by an unknown mechanism, PrPC can fold into different PrPSc conformers that may result in different prion strains that display specific disease phenotype (incubation time, clinical signs and lesion profile). Although the pathways for neurodegeneration as well as the involvement of brain inflammation in these diseases are not well understood, the spongiform changes, neuronal loss, gliosis and accumulation of PrPSc are the characteristic neuropathological lesions. Scrapie affecting small ruminants was the first identified TSE and has been considered the archetype of prion diseases, though atypical and new animal prion diseases continue to emerge highlighting the importance to investigate the lesion profile in naturally affected animals. In this report, we review the neuropathology and the neuroinflammation of animal prion diseases in natural hosts from scrapie, going through the zoonotic bovine spongiform encephalopathy (BSE), the chronic wasting disease (CWD) to the newly identified camel prion disease (CPD).


2019 ◽  
Vol 57 (1) ◽  
pp. 90-107
Author(s):  
Alyona V. Michael ◽  
Justin J. Greenlee ◽  
Tyler A. Harm ◽  
S. Jo Moore ◽  
Min Zhang ◽  
...  

Mammalian transmissible spongiform encephalopathies (TSEs) display marked activation of astrocytes and microglia that precedes neuronal loss. Investigation of clinical parallels between TSEs and other neurodegenerative protein misfolding diseases, such as Alzheimer’s disease, has revealed similar patterns of neuroinflammatory responses to the accumulation of self-propagating amyloids. The contribution of glial activation to the progression of protein misfolding diseases is incompletely understood, with evidence for mediation of both protective and deleterious effects. Glial populations are heterogeneously distributed throughout the brain and capable of dynamic transitions along a spectrum of functional activation states between pro- and antiinflammatory polarization extremes. Using a murine model of Rocky Mountain Laboratory scrapie, the neuroinflammatory response to prion infection was characterized by evaluating glial activation across 15 brain regions over time and correlating it to traditional markers of prion neuropathology, including vacuolation and PrPSc deposition. Quantitative immunohistochemistry was used to evaluate glial expression of iNOS and Arg1, markers of classical and alternative glial activation, respectively. The results indicate progressive upregulation of iNOS in microglia and a mixed astrocytic profile featuring iNOS expression in white matter tracts and detection of Arg1-positive populations throughout the brain. These data establish a temporospatial lesion profile for this prion infection model and demonstrate evidence of multiple glial activation states.


2021 ◽  
Vol 2 (3) ◽  
pp. 80-94
Author(s):  
Saif Jabbar Yasir ◽  
Taghreed Abdul Kareem Al- Makhzoomy

Prion diseases or transmissible spongiform encephalopathies (TSEs) are a family of rare progressive neurodegenerative disorders that affect both humans and animals. They are distinguished by long incubation periods, characteristic spongiform changes associated with neuronal loss, and a failure to induce inflammatory response. Prion diseases in animals, Scrapie in sheep, chronic wasting disease (CWD) in deer, bovine spongiform encephalopathy (commonly known as "mad cow disease") in cattle, and Creutzfeldt-Jakob disease in humans are all examples of infectious diseases. The prion protein (PrP) was identified in a patient in 2015, and it was previously believed to be the cause of all known mammalian prion diseases. However, The protein alpha-synuclein, which is thought to be responsible for MSA, was suggested to be the cause of the disease in 2015.


2009 ◽  
Vol 89 (4) ◽  
pp. 1105-1152 ◽  
Author(s):  
Adriano Aguzzi ◽  
Anna Maria Calella

Transmissible spongiform encephalopathies (TSEs) are inevitably lethal neurodegenerative diseases that affect humans and a large variety of animals. The infectious agent responsible for TSEs is the prion, an abnormally folded and aggregated protein that propagates itself by imposing its conformation onto the cellular prion protein (PrPC) of the host. PrPCis necessary for prion replication and for prion-induced neurodegeneration, yet the proximal causes of neuronal injury and death are still poorly understood. Prion toxicity may arise from the interference with the normal function of PrPC, and therefore, understanding the physiological role of PrPCmay help to clarify the mechanism underlying prion diseases. Here we discuss the evolution of the prion concept and how prion-like mechanisms may apply to other protein aggregation diseases. We describe the clinical and the pathological features of the prion diseases in human and animals, the events occurring during neuroinvasion, and the possible scenarios underlying brain damage. Finally, we discuss potential antiprion therapies and current developments in the realm of prion diagnostics.


Biomolecules ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 469
Author(s):  
Hasier Eraña ◽  
Jorge M. Charco ◽  
Ezequiel González-Miranda ◽  
Sandra García-Martínez ◽  
Rafael López-Moreno ◽  
...  

Transmissible spongiform encephalopathies or prion diseases are rapidly progressive neurodegenerative diseases, the clinical manifestation of which can resemble other promptly evolving neurological maladies. Therefore, the unequivocal ante-mortem diagnosis is highly challenging and was only possible by histopathological and immunohistochemical analysis of the brain at necropsy. Although surrogate biomarkers of neurological damage have become invaluable to complement clinical data and provide more accurate diagnostics at early stages, other neurodegenerative diseases show similar alterations hindering the differential diagnosis. To solve that, the detection of the pathognomonic biomarker of disease, PrPSc, the aberrantly folded isoform of the prion protein, could be used. However, the amounts in easily accessible tissues or body fluids at pre-clinical or early clinical stages are extremely low for the standard detection methods. The solution comes from the recent development of in vitro prion propagation techniques, such as Protein Misfolding Cyclic Amplification (PMCA) and Real Time-Quaking Induced Conversion (RT-QuIC), which have been already applied to detect minute amounts of PrPSc in different matrixes and make early diagnosis of prion diseases feasible in a near future. Herein, the most relevant tissues and body fluids in which PrPSc has been detected in animals and humans are being reviewed, especially those in which cell-free prion propagation systems have been used with diagnostic purposes.


2020 ◽  
Vol 21 (20) ◽  
pp. 7765
Author(s):  
Caterina Peggion ◽  
Roberto Stella ◽  
Paolo Lorenzon ◽  
Enzo Spisni ◽  
Alessandro Bertoli ◽  
...  

Prion diseases are rare transmissible neurodegenerative disorders caused by the accumulation of a misfolded isoform (PrPSc) of the cellular prion protein (PrPC) in the central nervous system (CNS). Neuropathological hallmarks of prion diseases are neuronal loss, astrogliosis, and enhanced microglial proliferation and activation. As immune cells of the CNS, microglia participate both in the maintenance of the normal brain physiology and in driving the neuroinflammatory response to acute or chronic (e.g., neurodegenerative disorders) insults. Microglia involvement in prion diseases, however, is far from being clearly understood. During this review, we summarize and discuss controversial findings, both in patient and animal models, suggesting a neuroprotective role of microglia in prion disease pathogenesis and progression, or—conversely—a microglia-mediated exacerbation of neurotoxicity in later stages of disease. We also will consider the active participation of PrPC in microglial functions, by discussing previous reports, but also by presenting unpublished results that support a role for PrPC in cytokine secretion by activated primary microglia.


2006 ◽  
Vol 7 (1-2) ◽  
pp. 97-105 ◽  
Author(s):  
Scott P. Leach ◽  
M. D. Salman ◽  
Dwayne Hamar

Transmissible spongiform encephalopathies (TSEs) are a family of neurodegenerative diseases characterized by their long incubation periods, progressive neurological changes, and spongiform appearance in the brain. There is much evidence to show that TSEs are caused by an isoform of the normal cellular surface prion protein PrPC. The normal function of PrPC is still unknown, but it exhibits properties of a cupro-protein, capable of binding up to six copper ions. There are two differing views on copper's role in prion diseases. While one view looks at the PrPC copper-binding as the trigger for conversion to PrPSc, the opposing viewpoint sees a lack of PrPC copper-binding resulting in the conformational change into the disease causing isoform. Manganese and zinc have been shown to interact with PrPC as well and have been found in abnormal levels in prion diseases. This review addresses the interaction between select trace elements and the PrPC.


2006 ◽  
Vol 20 (1) ◽  
pp. 18-24 ◽  
Author(s):  
Gwynivere A Davies ◽  
Adam R Bryant ◽  
John D Reynolds ◽  
Frank R Jirik ◽  
Keith A Sharkey

The gastrointestinal (GI) tract plays a central role in the pathogenesis of transmissible spongiform encephalopathies. These are human and animal diseases that include bovine spongiform encephalopathy, scrapie and Creutzfeldt-Jakob disease. They are uniformly fatal neurological diseases, which are characterized by ataxia and vacuolation in the central nervous system. Alhough they are known to be caused by the conversion of normal cellular prion protein to its infectious conformational isoform (PrPsc) the process by which this isoform is propagated and transported to the brain remains poorly understood. M cells, dendritic cells and possibly enteroendocrine cells are important in the movement of infectious prions across the GI epithelium. From there, PrPscpropagation requires B lymphocytes, dendritic cells and follicular dendritic cells of Peyer’s patches. The early accumulation of the disease-causing agent in the plexuses of the enteric nervous system supports the contention that the autonomic nervous system is important in disease transmission. This is further supported by the presence of PrPscin the ganglia of the parasympathetic and sympathetic nerves that innervate the GI tract. Additionally, the lymphoreticular system has been implicated as the route of transmission from the gut to the brain. Although normal cellular prion protein is found in the enteric nervous system, its role has not been characterized. Further research is required to understand how the cellular components of the gut wall interact to propagate and transmit infectious prions to develop potential therapies that may prevent the progression of transmissible spongiform encephalopathies.


Author(s):  
James W. Ironside ◽  
Matthew P. Frosch ◽  
Bernardino Ghetti

This chapter describes and illustrates the neuropathology of prion diseases, also known as transmissible spongiform encephalopathies. These diseases are characterized pathologically by varying combinations of spongiform change, neuronal loss, reactive gliosis, and prion protein (PrP) deposition. The morphologic pattern depends on the etiology of the disease and the genotype of the patient. Different clinicopathological phenotypes of sporadic Creutzfeldt-Jakob disease (CJD) have been described depending on the PRNP codon 129 genotype and the PrP isotype. A novel form known as variably protease-sensitive prionopathy has been recently identified. Familial prion diseases include familial CJD, Gerstmann-Sträussler-Scheinker disease, and fatal familial insomnia. Over 40 different PRNP mutations have been identified. Acquired prion diseases include Kuru; iatrogenic CJD, particularly in recipients of contaminated human pituitary hormone, and variant CJD, which seems closely related to bovine spongiform encephalopathy.


2018 ◽  
Vol 76 (10) ◽  
pp. 705-712
Author(s):  
Pedro Piccardo ◽  
David M. Asher

ABSTRACT Protein misfolding diseases are usually associated with deposits of single “key” proteins that somehow drive the pathology; β-amyloid and hyperphosphorylated tau accumulate in Alzheimer's disease, α-synuclein in Parkinson's disease, or abnormal prion protein (PrPTSE) in transmissible spongiform encephalopathies (TSEs or prion diseases). However, in some diseases more than two proteins accumulate in the same brain. These diseases might be considered “complex” proteinopathies. We have studied models of TSEs (to explore deposits of PrPTSE and of “secondary proteins”) infecting different strains and doses of TSE agent, factors that control incubation period, duration of illness and histopathology. Model TSEs allowed us to investigate whether different features of histopathology are independent of PrPTSE or appear as a secondary result of PrPTSE. Better understanding the complex proteinopathies may help to explain the wide spectrum of degenerative diseases and why some overlap clinically and histopathologically. These studies might also improve diagnosis and eventually even suggest new treatments for human neurodegenerative diseases.


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