1
|
Lawrence JA, Aguilar-Calvo P, Ojeda-Juárez D, Khuu H, Soldau K, Pizzo DP, Wang J, Malik A, Shay TF, Sullivan EE, Aulston B, Song SM, Callender JA, Sanchez H, Geschwind MD, Roy S, Rissman RA, Trejo J, Tanaka N, Wu C, Chen X, Patrick GN, Sigurdson CJ. Diminished Neuronal ESCRT-0 Function Exacerbates AMPA Receptor Derangement and Accelerates Prion-Induced Neurodegeneration. J Neurosci 2023; 43:3970-3984. [PMID: 37019623 PMCID: PMC10219035 DOI: 10.1523/jneurosci.1878-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Revised: 03/22/2023] [Accepted: 03/27/2023] [Indexed: 04/07/2023] Open
Abstract
Endolysosomal defects in neurons are central to the pathogenesis of prion and other neurodegenerative disorders. In prion disease, prion oligomers traffic through the multivesicular body (MVB) and are routed for degradation in lysosomes or for release in exosomes, yet how prions impact proteostatic pathways is unclear. We found that prion-affected human and mouse brain showed a marked reduction in Hrs and STAM1 (ESCRT-0), which route ubiquitinated membrane proteins from early endosomes into MVBs. To determine how the reduction in ESCRT-0 impacts prion conversion and cellular toxicity in vivo, we prion-challenged conditional knockout mice (male and female) having Hrs deleted from neurons, astrocytes, or microglia. The neuronal, but not astrocytic or microglial, Hrs-depleted mice showed a shortened survival and an acceleration in synaptic derangements, including an accumulation of ubiquitinated proteins, deregulation of phosphorylated AMPA and metabotropic glutamate receptors, and profoundly altered synaptic structure, all of which occurred later in the prion-infected control mice. Finally, we found that neuronal Hrs (nHrs) depletion increased surface levels of the cellular prion protein, PrPC, which may contribute to the rapidly advancing disease through neurotoxic signaling. Taken together, the reduced Hrs in the prion-affected brain hampers ubiquitinated protein clearance at the synapse, exacerbates postsynaptic glutamate receptor deregulation, and accelerates neurodegeneration.SIGNIFICANCE STATEMENT Prion diseases are rapidly progressive neurodegenerative disorders characterized by prion aggregate spread through the central nervous system. Early disease features include ubiquitinated protein accumulation and synapse loss. Here, we investigate how prion aggregates alter ubiquitinated protein clearance pathways (ESCRT) in mouse and human prion-infected brain, discovering a marked reduction in Hrs. Using a prion-infection mouse model with neuronal Hrs (nHrs) depleted, we show that low neuronal Hrs is detrimental and markedly shortens survival time while accelerating synaptic derangements, including ubiquitinated protein accumulation, indicating that Hrs loss exacerbates prion disease progression. Additionally, Hrs depletion increases the surface distribution of prion protein (PrPC), linked to aggregate-induced neurotoxic signaling, suggesting that Hrs loss in prion disease accelerates disease through enhancing PrPC-mediated neurotoxic signaling.
Collapse
Affiliation(s)
- Jessica A Lawrence
- Department of Pathology, University of California, San Diego, La, Jolla, California, 92093
| | - Patricia Aguilar-Calvo
- Department of Pathology, University of California, San Diego, La, Jolla, California, 92093
| | - Daniel Ojeda-Juárez
- Department of Pathology, University of California, San Diego, La, Jolla, California, 92093
| | - Helen Khuu
- Department of Pathology, University of California, San Diego, La, Jolla, California, 92093
| | - Katrin Soldau
- Department of Pathology, University of California, San Diego, La, Jolla, California, 92093
| | - Donald P Pizzo
- Department of Pathology, University of California, San Diego, La, Jolla, California, 92093
| | - Jin Wang
- Department of Pathology, University of California, San Diego, La, Jolla, California, 92093
| | - Adela Malik
- Department of Pathology, University of California, San Diego, La, Jolla, California, 92093
| | - Timothy F Shay
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125
| | - Erin E Sullivan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125
| | - Brent Aulston
- Department of Neurosciences, University of California, San Diego, La Jolla, California 92093
| | - Seung Min Song
- Department of Pathology, University of California, San Diego, La, Jolla, California, 92093
| | - Julia A Callender
- Department of Pathology, University of California, San Diego, La, Jolla, California, 92093
| | - Henry Sanchez
- Department of Pathology, University of California, San Francisco, San Francisco, California 94143
| | - Michael D Geschwind
- Department of Neurology, Memory and Aging Center, University of California, San Francisco (UCSF), San Francisco, California 94143
| | - Subhojit Roy
- Department of Pathology, University of California, San Diego, La, Jolla, California, 92093
- Department of Neurosciences, University of California, San Diego, La Jolla, California 92093
| | - Robert A Rissman
- Department of Neurosciences, University of California, San Diego, La Jolla, California 92093
| | - JoAnn Trejo
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093
| | - Nobuyuki Tanaka
- Division of Tumor Immunobiology, Miyagi Cancer Center Research Institute, Natori 981-1293, Japan
- Division of Tumor Immunobiology, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan
| | - Chengbiao Wu
- Department of Neurosciences, University of California, San Diego, La Jolla, California 92093
| | - Xu Chen
- Department of Neurosciences, University of California, San Diego, La Jolla, California 92093
| | - Gentry N Patrick
- Department of Biology, University of California, San Diego, La Jolla, California 92093
| | - Christina J Sigurdson
- Department of Pathology, University of California, San Diego, La, Jolla, California, 92093
- Department of Pathology, Microbiology, and Immunology, University of California, Davis, Davis, California 95616
- Department of Medicine, University of California, San Diego, La Jolla, California 92093
| |
Collapse
|
2
|
Shoup D, Priola SA. Cell biology of prion strains in vivo and in vitro. Cell Tissue Res 2023; 392:269-283. [PMID: 35107622 PMCID: PMC11249200 DOI: 10.1007/s00441-021-03572-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 12/22/2021] [Indexed: 02/01/2023]
Abstract
The properties of infectious prions and the pathology of the diseases they cause are dependent upon the unique conformation of each prion strain. How the pathology of prion disease correlates with different strains and genetic backgrounds has been investigated via in vivo assays, but how interactions between specific prion strains and cell types contribute to the pathology of prion disease has been dissected more effectively using in vitro cell lines. Observations made through in vivo and in vitro assays have informed each other with regard to not only how genetic variation influences prion properties, but also how infectious prions are taken up by cells, modified by cellular processes and propagated, and the cellular components they rely on for persistent infection. These studies suggest that persistent cellular infection results from a balance between prion propagation and degradation. This balance may be shifted depending upon how different cell lines process infectious prions, potentially altering prion stability, and how fast they can be transported to the lysosome. Thus, in vitro studies have given us a deeper understanding of the interactions between different prions and cell types and how they may influence prion disease phenotypes in vivo.
Collapse
Affiliation(s)
- Daniel Shoup
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institutes of Health, National Institute of Allergy and Infectious Diseases, Hamilton, MT, 59840, USA
| | - Suzette A Priola
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institutes of Health, National Institute of Allergy and Infectious Diseases, Hamilton, MT, 59840, USA.
| |
Collapse
|
3
|
Cholesterol and its reciprocal association with prion infection. Cell Tissue Res 2022; 392:235-246. [PMID: 35821439 DOI: 10.1007/s00441-022-03669-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Accepted: 07/04/2022] [Indexed: 11/02/2022]
Abstract
Prion diseases are incurable, infectious and fatal neurodegenerative diseases that affect both humans and animals. The pathogenesis of prion disease involves the misfolding of the cellular prion protein, PrPC, to a disease-causing conformation, PrPSc, in the brain. The exact mechanism of conversion of PrPC to PrPSc is not clear; however, there are numerous studies supporting that this process of misfolding requires the association of PrPC with lipid raft domains of the plasma membrane. An increase in the cellular cholesterol content with prion infection has been observed in both in vivo and in vitro studies. As cholesterol is critical for the formation of lipid rafts, on the one hand, this increase may be related to, or aiding in, the process of prion conversion. On the other hand, increased cholesterol levels may affect neuronal viability. Here, we discuss current literature on the underlying mechanisms and potential consequences of elevated neuronal cholesterol in prion infection and advancements in prion disease therapeutics targeting brain cholesterol homeostasis.
Collapse
|
4
|
Huang Y, Feng Y, Cui L, Yang L, Zhang Q, Zhang J, Jiang X, Zhang X, Lv Y, Jia JZ, Zhang DX, Huang YS. Autophagy-Related LC3 Accumulation Interacted Directly With LIR Containing RIPK1 and RIPK3, Stimulating Necroptosis in Hypoxic Cardiomyocytes. Front Cell Dev Biol 2021; 9:679637. [PMID: 34368130 PMCID: PMC8344065 DOI: 10.3389/fcell.2021.679637] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 06/16/2021] [Indexed: 11/13/2022] Open
Abstract
The exact relationships and detailed mechanisms between autophagy and necroptosis remain obscure. Here, we demonstrated the link between accumulated autophagosome and necroptosis by intervening with autophagic flux. We first confirmed that the LC3 interacting region (LIR) domain is present in the protein sequences of RIPK1 and RIPK3. Mutual effects among LC3, RIPK1, and RIPK3 have been identified in myocardium and cardiomyocytes. Direct LC3-RIPK1 and LC3-RIPK3 interactions were confirmed by pull-down assays, and their interactions were deleted after LIR domain mutation. Moreover, after disrupting autophagic flux under normoxia with bafilomycin A1 treatment, or with LC3 or ATG5 overexpression adenovirus, RIPK1, RIPK3, p-RIPK3, and p-MLKL levels increased, suggesting necroptosis activation. Severe disruptions in autophagic flux were observed under hypoxia and bafilomycin A1 co-treated cardiomyocytes and myocardium and led to more significant activation of necroptosis. Conversely, after alleviating hypoxia-induced autophagic flux impairment with LC3 or ATG5 knockdown adenovirus, the effects of hypoxia on RIPK1 and RIPK3 levels were reduced, which resulted in decreased p-RIPK3 and p-MLKL. Furthermore, necroptosis was inhibited by siRNAs against RIPK1 and RIPK3 under hypoxia or normoxia. Based on our results, LIR domain mediated LC3-RIPK1 and LC3-RIPK3 interaction. Besides, autophagosome accumulation under hypoxia lead to necrosome formation and, in turn, necroptosis, while when autophagic flux was uninterrupted, RIPK1 and RIPK3 were cleared through an autophagy-related pathway which inhibited necroptosis. These findings provide novel insights for the role of LC3 in regulating cardiomyocyte necroptosis, indicating its therapeutic potential in the prevention and treatment of hypoxic myocardial injury and other hypoxia-related diseases.
Collapse
Affiliation(s)
- Yao Huang
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Burn Research, Southwest Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Yanhai Feng
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Burn Research, Southwest Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Lin Cui
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Burn Research, Southwest Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Lei Yang
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Burn Research, Southwest Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Qiong Zhang
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Burn Research, Southwest Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Junhui Zhang
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Burn Research, Southwest Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Xupin Jiang
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Burn Research, Southwest Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Xingyue Zhang
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Burn Research, Southwest Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Yanling Lv
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Burn Research, Southwest Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Jie-Zhi Jia
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Burn Research, Southwest Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Dong-Xia Zhang
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Burn Research, Southwest Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Yue-Sheng Huang
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Burn Research, Southwest Hospital, Army Medical University (Third Military Medical University), Chongqing, China
- Department of Wound Repair, and Institute of Wound Repair, Shenzhen People’s Hospital (The Second Clinical Medical College, Jinan University; The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen, China
| |
Collapse
|
5
|
Cerda-Troncoso C, Varas-Godoy M, Burgos PV. Pro-Tumoral Functions of Autophagy Receptors in the Modulation of Cancer Progression. Front Oncol 2021; 10:619727. [PMID: 33634029 PMCID: PMC7902017 DOI: 10.3389/fonc.2020.619727] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 12/10/2020] [Indexed: 12/20/2022] Open
Abstract
Cancer progression involves a variety of pro-tumorigenic biological processes including cell proliferation, migration, invasion, and survival. A cellular pathway implicated in these pro-tumorigenic processes is autophagy, a catabolic route used for recycling of cytoplasmic components to generate macromolecular building blocks and energy, under stress conditions, to remove damaged cellular constituents to adapt to changing nutrient conditions and to maintain cellular homeostasis. During autophagy, cells form a double-membrane sequestering a compartment termed the phagophore, which matures into an autophagosome. Following fusion with the lysosome, the cargo is degraded inside the autolysosomes and the resulting macromolecules released back into the cytosol for reuse. Cancer cells use this recycling system during cancer progression, however the key autophagy players involved in this disease is unclear. Accumulative evidences show that autophagy receptors, crucial players for selective autophagy, are overexpressed during cancer progression, yet the mechanisms whereby pro-tumorigenic biological processes are modulated by these receptors remains unknown. In this review, we summarized the most important findings related with the pro-tumorigenic role of autophagy receptors p62/SQSTM1, NBR1, NDP52, and OPTN in cancer progression. In addition, we showed the most relevant cargos degraded by these receptors that have been shown to function as critical regulators of pro-tumorigenic processes. Finally, we discussed the role of autophagy receptors in the context of the cellular pathways implicated in this disease, such as growth factors signaling, oxidative stress response and apoptosis. In summary, we highlight that autophagy receptors should be considered important players of cancer progression, which could offer a niche for the development of novel diagnosis and cancer treatment strategies.
Collapse
Affiliation(s)
- Cristóbal Cerda-Troncoso
- Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile
| | - Manuel Varas-Godoy
- Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile
| | - Patricia V. Burgos
- Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Chile
- Centro de Envejecimiento y Regeneración (CARE-UC), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| |
Collapse
|
6
|
Shoup D, Priola SA. The Size and Stability of Infectious Prion Aggregates Fluctuate Dynamically during Cellular Uptake and Disaggregation. Biochemistry 2021; 60:398-411. [PMID: 33497187 DOI: 10.1021/acs.biochem.0c00923] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Prion diseases arise when PrPSc, an aggregated, infectious, and insoluble conformer of the normally soluble mammalian prion protein, PrPC, catalyzes the conversion of PrPC into more PrPSc, which then accumulates in the brain leading to disease. PrPSc is the primary, if not sole, component of the infectious prion. Despite the stability and protease insensitivity of PrPSc aggregates, they can be degraded after cellular uptake. However, how cells disassemble and degrade PrPSc is poorly understood. In this work, we analyzed how the protease sensitivity and size distribution of PrPSc aggregates from two different mouse-adapted prion strains, 22L, that can persistently infect cells and 87V, that cannot, changed during cellular uptake. We show that within the first 4 h following uptake large PrPSc aggregates from both prion strains become less resistant to digestion by proteinase K (PK) through a mechanism that is dependent upon the acidic environment of endocytic vesicles. We further show that during disassembly, PrPSc aggregates from both strains become more resistant to PK digestion through the apparent removal of protease-sensitive PrPSc, with PrPSc from the 87V strain disassembled more readily than PrPSc from the 22L strain. Taken together, our data demonstrate that the sizes and stabilities of PrPSc from different prion strains change during cellular uptake and degradation, thereby potentially impacting the ability of prions to infect cells.
Collapse
Affiliation(s)
- Daniel Shoup
- Rocky Mountain Laboratories, Laboratory of Persistent Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana 59840, United States
| | - Suzette A Priola
- Rocky Mountain Laboratories, Laboratory of Persistent Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana 59840, United States
| |
Collapse
|
7
|
A New Take on Prion Protein Dynamics in Cellular Trafficking. Int J Mol Sci 2020; 21:ijms21207763. [PMID: 33092231 PMCID: PMC7589859 DOI: 10.3390/ijms21207763] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 10/14/2020] [Accepted: 10/14/2020] [Indexed: 12/12/2022] Open
Abstract
The mobility of cellular prion protein (PrPC) in specific cell membrane domains and among distinct cell compartments dictates its molecular interactions and directs its cell function. PrPC works in concert with several partners to organize signaling platforms implicated in various cellular processes. The scaffold property of PrPC is able to gather a molecular repertoire to create heterogeneous membrane domains that favor endocytic events. Dynamic trafficking of PrPC through multiple pathways, in a well-orchestrated mechanism of intra and extracellular vesicular transport, defines its functional plasticity, and also assists the conversion and spreading of its infectious isoform associated with neurodegenerative diseases. In this review, we highlight how PrPC traffics across intra- and extracellular compartments and the consequences of this dynamic transport in governing cell functions and contributing to prion disease pathogenesis.
Collapse
|
8
|
The Role of Vesicle Trafficking Defects in the Pathogenesis of Prion and Prion-Like Disorders. Int J Mol Sci 2020; 21:ijms21197016. [PMID: 32977678 PMCID: PMC7582986 DOI: 10.3390/ijms21197016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/15/2020] [Accepted: 09/21/2020] [Indexed: 11/26/2022] Open
Abstract
Prion diseases are fatal and transmissible neurodegenerative diseases in which the cellular form of the prion protein ‘PrPc’, misfolds into an infectious and aggregation prone isoform termed PrPSc, which is the primary component of prions. Many neurodegenerative diseases, like Alzheimer’s disease, Parkinson’s disease, and polyglutamine diseases, such as Huntington’s disease, are considered prion-like disorders because of the common characteristics in the propagation and spreading of misfolded proteins that they share with the prion diseases. Unlike prion diseases, these are non-infectious outside experimental settings. Many vesicular trafficking impairments, which are observed in prion and prion-like disorders, favor the accumulation of the pathogenic amyloid aggregates. In addition, many of the vesicular trafficking impairments that arise in these diseases, turn out to be further aggravating factors. This review offers an insight into the currently known vesicular trafficking defects in these neurodegenerative diseases and their implications on disease progression. These findings suggest that these impaired trafficking pathways may represent similar therapeutic targets in these classes of neurodegenerative disorders.
Collapse
|
9
|
López-Pérez Ó, Badiola JJ, Bolea R, Ferrer I, Llorens F, Martín-Burriel I. An Update on Autophagy in Prion Diseases. Front Bioeng Biotechnol 2020; 8:975. [PMID: 32984276 PMCID: PMC7481332 DOI: 10.3389/fbioe.2020.00975] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 07/27/2020] [Indexed: 12/18/2022] Open
Abstract
Autophagy is a dynamic intracellular mechanism involved in protein and organelle turnover through lysosomal degradation. When properly regulated, autophagy supports normal cellular and developmental processes, whereas defects in autophagic degradation have been associated with several pathologies, including prion diseases. Prion diseases, or transmissible spongiform encephalopathies (TSE), are a group of fatal neurodegenerative disorders characterized by the accumulation of the pathological misfolded isoform (PrPSc) of the physiological cellular prion protein (PrPc) in the central nervous system. Autophagic vacuoles have been described in experimental models of TSE and in the natural disease in humans. The precise connection of this process with prion-related neuropathology, or even whether autophagy is completely beneficial or pathogenic during neurodegeneration, is poorly understood. Thus, the biological role of autophagy in these diseases is still open to debate. During the last years, researchers have used a wide range of morphological, genetic and biochemical methods to monitor and manipulate the autophagic pathway and thus determine the specific role of this process in TSE. It has been suggested that PrPc could play a crucial role in modulating the autophagic pathway in neuronal cells, and the presence of abnormal autophagic activity has been frequently observed in several models of TSE both in vitro and in vivo, as well as in human prion diseases. Altogether, these findings suggest that autophagy is implicated in prion neuropathology and points to an impairment or failure of the process, potentially contributing to the pathogenesis of the disease. Additionally, autophagy is now emerging as a host defense response in controlling prion infection that plays a protective role by facilitating the clearance of aggregation-prone proteins accumulated within neurons. Since autophagy is one of the pathways of PrPSc degradation, and drug-induced stimulation of autophagic flux (the dynamic process of autophagic degradation activity) produces anti-prion effects, new treatments based on its activation have been tested to develop therapeutic strategies for prion diseases. In this review, we summarize previous and recent findings concerning the role of autophagy in TSE.
Collapse
Affiliation(s)
- Óscar López-Pérez
- Laboratorio de Genética Bioquímica (LAGENBIO), Instituto Agroalimentario de Aragón-IA2, Instituto de Investigación Sanitaria Aragón-IISA, Universidad de Zaragoza, Zaragoza, Spain.,Centro de Encefalopatías y Enfermedades Transmisibles Emergentes (CEETE), Instituto Agroalimentario de Aragón-IA2, Instituto de Investigación Sanitaria Aragón-IISA, Universidad de Zaragoza, Zaragoza, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto Carlos III, L'Hospitalet de Llobregat, Barcelona, Spain.,Instituto de Investigación Biomédica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain
| | - Juan José Badiola
- Centro de Encefalopatías y Enfermedades Transmisibles Emergentes (CEETE), Instituto Agroalimentario de Aragón-IA2, Instituto de Investigación Sanitaria Aragón-IISA, Universidad de Zaragoza, Zaragoza, Spain
| | - Rosa Bolea
- Centro de Encefalopatías y Enfermedades Transmisibles Emergentes (CEETE), Instituto Agroalimentario de Aragón-IA2, Instituto de Investigación Sanitaria Aragón-IISA, Universidad de Zaragoza, Zaragoza, Spain
| | - Isidro Ferrer
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto Carlos III, L'Hospitalet de Llobregat, Barcelona, Spain.,Instituto de Investigación Biomédica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain.,Departamento de Patología y Terapéutica Experimental, Universidad de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Franc Llorens
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto Carlos III, L'Hospitalet de Llobregat, Barcelona, Spain.,Instituto de Investigación Biomédica de Bellvitge (IDIBELL), L'Hospitalet de Llobregat, Barcelona, Spain.,Department of Neurology, Clinical Dementia Center and National Reference Center for CJD Surveillance, University Medical School, Göttingen, Germany
| | - Inmaculada Martín-Burriel
- Laboratorio de Genética Bioquímica (LAGENBIO), Instituto Agroalimentario de Aragón-IA2, Instituto de Investigación Sanitaria Aragón-IISA, Universidad de Zaragoza, Zaragoza, Spain.,Centro de Encefalopatías y Enfermedades Transmisibles Emergentes (CEETE), Instituto Agroalimentario de Aragón-IA2, Instituto de Investigación Sanitaria Aragón-IISA, Universidad de Zaragoza, Zaragoza, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto Carlos III, Zaragoza, Spain
| |
Collapse
|
10
|
Moon JH, Park SY. Prion peptide-mediated calcium level alteration governs neuronal cell damage through AMPK-autophagy flux. Cell Commun Signal 2020; 18:109. [PMID: 32650778 PMCID: PMC7353712 DOI: 10.1186/s12964-020-00590-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 04/30/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The distinctive molecular structure of the prion protein, PrPsc, is established only in mammals with infectious prion diseases. Prion protein characterizes either the transmissible pathogen itself or a primary constituent of the disease. Our report suggested that prion protein-mediated neuronal cell death is triggered by the autophagy flux. However, the alteration of intracellular calcium levels, AMPK activity in prion models has not been described. This study is focused on the effect of the changes in intracellular calcium levels on AMPK/autophagy flux pathway and PrP (106-126)-induced neurotoxicity. METHODS Western blot and Immunocytochemistry was used to detect AMPK and autophagy-related protein expression. Flow cytometry and a TdT-mediated biotin-16-dUTP nick-end labeling (TUNEL) assay were used to detect the percentage of apoptotic cells. Calcium measurement was employed using fluo-4 by confocal microscope. RESULTS We examined the effect of calcium homeostasis alterations induced by human prion peptide on the autophagy flux in neuronal cells. Treatment with human prion peptide increased the intracellular calcium concentration and induced cell death in primary neurons as well as in a neuronal cell line. Using pharmacological inhibitors, we showed that the L-type calcium channel is involved in the cellular entry of calcium ions. Inhibition of calcium uptake prevented autophagic cell death and reduction in AMP-activated protein kinase (AMPK) activity induced by human prion peptide. CONCLUSION Our data demonstrated that prion peptide-mediated calcium inflow plays a pivotal role in prion peptide-induced autophagic cell death, and reduction in AMPK activity in neurons. Altogether, our results suggest that calcium influx might play a critical role in neurodegenerative diseases, including prion diseases. Video Abstract.
Collapse
Affiliation(s)
- Ji-Hong Moon
- Biosafety Research Institute, College of Veterinary Medicine, Jeonbuk National University, Gobong ro, Iksan, Jeonbuk, 54596, South Korea
| | - Sang-Youel Park
- Biosafety Research Institute, College of Veterinary Medicine, Jeonbuk National University, Gobong ro, Iksan, Jeonbuk, 54596, South Korea.
| |
Collapse
|
11
|
Jones E, Mead S. Genetic risk factors for Creutzfeldt-Jakob disease. Neurobiol Dis 2020; 142:104973. [PMID: 32565065 DOI: 10.1016/j.nbd.2020.104973] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 05/18/2020] [Accepted: 06/13/2020] [Indexed: 10/24/2022] Open
Abstract
Prion diseases are a group of fatal neurodegenerative disorders of mammals that share a central role for prion protein (PrP, gene PRNP) in their pathogenesis. Prions are infectious agents that account for the observed transmission of prion diseases between humans and animals in certain circumstances. The prion mechanism invokes a misfolded and multimeric assembly of PrP (a prion) that grows by templating of the normal protein and propagates by fission. Aside from the medical and public health notoriety of acquired prion diseases, the conditions have attracted interest as it has been realized that common neurodegenerative disorders share so-called prion-like mechanisms. In this article we will expand on recent evidence for new genetic loci that alter the risk of human prion disease. The most common human prion disease, sporadic Creutzfeldt-Jakob disease (sCJD), is characterized by the seemingly spontaneous appearance of prions in the brain. Genetic variation within PRNP is associated with all types of prion diseases, in particular, heterozygous genotypes at codons 129 and 219 have long been known to be strong protective factors against sCJD. A large number of rare mutations have been described in PRNP that cause autosomal dominant inherited prion diseases. Two loci recently identified by genome-wide association study increase sCJD risk, including variants in or near to STX6 and GAL3ST1. STX6 encodes syntaxin-6, a component of SNARE complexes with cellular roles that include the fusion of intracellular vesicles with target membranes. GAL3ST1 encodes cerebroside sulfotransferase, the only enzyme that sulfates sphingolipids to make sulfatides, a major lipid component of myelin. We discuss how these roles may modify the pathogenesis of prion diseases and their relevance for other neurodegenerative disorders.
Collapse
Affiliation(s)
- Emma Jones
- MRC Prion Unit at University College London (UCL), UCL Institute of Prion Diseases, 33 Cleveland Street, W1W 7FF, United Kingdom
| | - Simon Mead
- MRC Prion Unit at University College London (UCL), UCL Institute of Prion Diseases, 33 Cleveland Street, W1W 7FF, United Kingdom.
| |
Collapse
|
12
|
Sora V, Kumar M, Maiani E, Lambrughi M, Tiberti M, Papaleo E. Structure and Dynamics in the ATG8 Family From Experimental to Computational Techniques. Front Cell Dev Biol 2020; 8:420. [PMID: 32587856 PMCID: PMC7297954 DOI: 10.3389/fcell.2020.00420] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 05/06/2020] [Indexed: 12/31/2022] Open
Abstract
Autophagy is a conserved and essential intracellular mechanism for the removal of damaged components. Since autophagy deregulation is linked to different kinds of pathologies, it is fundamental to gain knowledge on the fine molecular and structural details related to the core proteins of the autophagy machinery. Among these, the family of human ATG8 proteins plays a central role in recruiting other proteins to the different membrane structures involved in the autophagic pathway. Several experimental structures are available for the members of the ATG8 family alone or in complex with their different biological partners, including disordered regions of proteins containing a short linear motif called LC3 interacting motif. Recently, the first structural details of the interaction of ATG8 proteins with biological membranes came into light. The availability of structural data for human ATG8 proteins has been paving the way for studies on their structure-function-dynamic relationship using biomolecular simulations. Experimental and computational structural biology can help to address several outstanding questions on the mechanism of human ATG8 proteins, including their specificity toward different interactors, their association with membranes, the heterogeneity of their conformational ensemble, and their regulation by post-translational modifications. We here summarize the main results collected so far and discuss the future perspectives within the field and the knowledge gaps. Our review can serve as a roadmap for future structural and dynamics studies of the ATG8 family members in health and disease.
Collapse
Affiliation(s)
- Valentina Sora
- Computational Biology Laboratory, Center for Autophagy, Recycling and Disease, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Mukesh Kumar
- Computational Biology Laboratory, Center for Autophagy, Recycling and Disease, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Emiliano Maiani
- Computational Biology Laboratory, Center for Autophagy, Recycling and Disease, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Matteo Lambrughi
- Computational Biology Laboratory, Center for Autophagy, Recycling and Disease, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Matteo Tiberti
- Computational Biology Laboratory, Center for Autophagy, Recycling and Disease, Danish Cancer Society Research Center, Copenhagen, Denmark
| | - Elena Papaleo
- Computational Biology Laboratory, Center for Autophagy, Recycling and Disease, Danish Cancer Society Research Center, Copenhagen, Denmark
- Translational Disease System Biology, Faculty of Health and Medical Sciences, Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
13
|
Minikel EV, Kuhn E, Cocco AR, Vallabh SM, Hartigan CR, Reidenbach AG, Safar JG, Raymond GJ, McCarthy MD, O'Keefe R, Llorens F, Zerr I, Capellari S, Parchi P, Schreiber SL, Carr SA. Domain-specific Quantification of Prion Protein in Cerebrospinal Fluid by Targeted Mass Spectrometry. Mol Cell Proteomics 2019; 18:2388-2400. [PMID: 31558565 PMCID: PMC6885701 DOI: 10.1074/mcp.ra119.001702] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 09/16/2019] [Indexed: 01/11/2023] Open
Abstract
Therapies currently in preclinical development for prion disease seek to lower prion protein (PrP) expression in the brain. Trials of such therapies are likely to rely on quantification of PrP in cerebrospinal fluid (CSF) as a pharmacodynamic biomarker and possibly as a trial endpoint. Studies using PrP ELISA kits have shown that CSF PrP is lowered in the symptomatic phase of disease, a potential confounder for reading out the effect of PrP-lowering drugs in symptomatic patients. Because misfolding or proteolytic cleavage could potentially render PrP invisible to ELISA even if its concentration were constant or increasing in disease, we sought to establish an orthogonal method for CSF PrP quantification. We developed a multi-species targeted mass spectrometry method based on multiple reaction monitoring (MRM) of nine PrP tryptic peptides quantified relative to an isotopically labeled recombinant protein standard for human samples, or isotopically labeled synthetic peptides for nonhuman species. Analytical validation experiments showed process replicate coefficients of variation below 15%, good dilution linearity and recovery, and suitable performance for both CSF and brain homogenate and across humans as well as preclinical species of interest. In n = 55 CSF samples from individuals referred to prion surveillance centers with rapidly progressive dementia, all six human PrP peptides, spanning the N- and C-terminal domains of PrP, were uniformly reduced in prion disease cases compared with individuals with nonprion diagnoses. Thus, lowered CSF PrP concentration in prion disease is a genuine result of the disease process and not an artifact of ELISA-based measurement. As a result, dose-finding studies for PrP lowering drugs may need to be conducted in presymptomatic at-risk individuals rather than in symptomatic patients. We provide a targeted mass spectrometry-based method suitable for preclinical quantification of CSF PrP as a tool for drug development.
Collapse
Affiliation(s)
- Eric Vallabh Minikel
- Chemical Biology and Therapeutics Science Program, Broad Institute of MIT and Harvard, Cambridge, MA 02142; Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, MA 02115; Prion Alliance, Cambridge, MA 02139; Proteomics Platform, Broad Institute of MIT and Harvard, Cambridge, MA 02142.
| | - Eric Kuhn
- Proteomics Platform, Broad Institute of MIT and Harvard, Cambridge, MA 02142; Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, MA 02115
| | - Alexandra R Cocco
- Proteomics Platform, Broad Institute of MIT and Harvard, Cambridge, MA 02142
| | - Sonia M Vallabh
- Chemical Biology and Therapeutics Science Program, Broad Institute of MIT and Harvard, Cambridge, MA 02142; Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, MA 02115; Prion Alliance, Cambridge, MA 02139
| | | | - Andrew G Reidenbach
- Chemical Biology and Therapeutics Science Program, Broad Institute of MIT and Harvard, Cambridge, MA 02142
| | - Jiri G Safar
- Departments of Pathology and Neurology Case Western Reserve University, Cleveland, OH 44106
| | - Gregory J Raymond
- Laboratory of Persistent Viral Diseases, NIAID Rocky Mountain Labs, Hamilton, MT 59840
| | - Michael D McCarthy
- Environmental Health and Safety, Broad Institute of MIT and Harvard, Cambridge, MA 02142
| | - Rhonda O'Keefe
- Environmental Health and Safety, Broad Institute of MIT and Harvard, Cambridge, MA 02142
| | - Franc Llorens
- National Reference Center for TSE, Georg-August University, Göttingen, 37073, Germany; Biomedical Research Networking Center on Neurodegenerative Diseases (CIBERNED), L'Hospitalet de Llobregat, 08908, Barcelona, Spain
| | - Inga Zerr
- National Reference Center for TSE, Georg-August University, Göttingen, 37073, Germany
| | - Sabina Capellari
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, 40139, Italy; Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, 40123, Italy
| | - Piero Parchi
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, 40139, Italy; Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna, 40138, Italy
| | - Stuart L Schreiber
- Chemical Biology and Therapeutics Science Program, Broad Institute of MIT and Harvard, Cambridge, MA 02142; Department of Chemistry & Chemical Biology, Harvard University, Cambridge, MA 02138
| | - Steven A Carr
- Proteomics Platform, Broad Institute of MIT and Harvard, Cambridge, MA 02142.
| |
Collapse
|
14
|
Translocating a High-Affinity Designer TIMP-1 to the Cell Membrane for Total Renal Carcinoma Inhibition: Putting the Prion Protein to Good Use. Mol Cell Biol 2019; 39:MCB.00128-19. [PMID: 31208977 DOI: 10.1128/mcb.00128-19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Accepted: 06/06/2019] [Indexed: 12/20/2022] Open
Abstract
Membrane type 1-matrix metalloproteinase (MT1-MMP) and tumor necrosis factor α (TNF-α)-converting enzyme (TACE) are prominent membrane-anchored metalloproteinases that regulate the turnover of extracellular matrix (ECM) components and bioactive molecules required for cancer proliferation. In this study, we describe a novel approach that would allow tissue inhibitor of metalloproteinase 1 (TIMP-1), the endogenous inhibitor of the matrix metalloproteinases (MMPs), to be translocated to the cell membrane for simultaneous MT1-MMP/TACE inhibition. We achieve this by fusing T1TACE, a designer TIMP-1 with superb affinities for MT1-MMP and TACE, to the glycosyl-phosphatidyl inositol anchor of prions to create a membrane-tethered, broad-spectrum inhibitor, named T1Pr αTACE, that colocalizes with MT1-MMP and TACE on the cell surface. Transduction of T1Pr αTACE in human fibrosarcoma cells results not only in a substantial reduction in gelatinolytic and TNF-α/heparin binding epithelial growth factor shedding activities but also in a loss of tubulogenic capability in three-dimensional matrices. In renal carcinoma, T1Pr αTACE triggers cellular senescence and disrupts MMP-mediated proteolysis of ECM components such as fibronectin and collagen I, leading to an impairment in cell motility and survival under both in vitro and in vivo conditions. Taken together, our findings may provide a new perspective in TIMP targeting that could be exploited to halt metastatic renal carcinoma progression.
Collapse
|
15
|
de la Ballina LR, Munson MJ, Simonsen A. Lipids and Lipid-Binding Proteins in Selective Autophagy. J Mol Biol 2019; 432:135-159. [PMID: 31202884 DOI: 10.1016/j.jmb.2019.05.051] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 05/29/2019] [Accepted: 05/29/2019] [Indexed: 02/07/2023]
Abstract
Eukaryotic cells have the capacity to degrade intracellular components through a lysosomal degradation pathway called macroautophagy (henceforth referred to as autophagy) in which superfluous or damaged cytosolic entities are engulfed and separated from the rest of the cell constituents into double membraned vesicles known as autophagosomes. Autophagosomes then fuse with endosomes and lysosomes, where cargo is broken down into basic building blocks that are released to the cytoplasm for the cell to reuse. Autophagic degradation can target either cytoplasmic material in bulk (non-selective autophagy) or particular cargo in what is called selective autophagy. Proper autophagic turnover requires the orchestrated participation of several players that need to be tightly and temporally coordinated. Whereas a large number of autophagy-related (ATG) proteins have been identified and their functions and regulation are starting to be understood, there is substantially less knowledge regarding the specific lipids constituting the autophagic membranes as well as their role in initiating, enabling or regulating the autophagic process. This review focuses on lipids and their corresponding binding proteins that are crucial in the process of selective autophagy.
Collapse
Affiliation(s)
- Laura R de la Ballina
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway; Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Michael J Munson
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway; Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Anne Simonsen
- Department of Molecular Medicine, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo, Norway; Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
| |
Collapse
|
16
|
Hellerschmied D, Serebrenik YV, Shao L, Burslem GM, Crews CM. Protein folding state-dependent sorting at the Golgi apparatus. Mol Biol Cell 2019; 30:2296-2308. [PMID: 31166830 PMCID: PMC6743468 DOI: 10.1091/mbc.e19-01-0069] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
In eukaryotic cells, organelle-specific protein quality control (PQC) is critical for maintaining cellular homeostasis. Despite the Golgi apparatus being the major protein processing and sorting site within the secretory pathway, how it contributes to PQC has remained largely unknown. Using different chemical biology-based protein unfolding systems, we reveal the segregation of unfolded proteins from folded proteins in the Golgi. Quality control (QC) substrates are subsequently exported in distinct carriers, which likely contain unfolded proteins as well as highly oligomerized cargo that mimic protein aggregates. At an additional sorting step, oligomerized proteins are committed to lysosomal degradation, while unfolded proteins localize to the endoplasmic reticulum (ER) and associate with chaperones. These results highlight the existence of checkpoints at which QC substrates are selected for Golgi export and lysosomal degradation. Our data also suggest that the steady-state ER localization of misfolded proteins, observed for several disease-causing mutants, may have different origins.
Collapse
Affiliation(s)
| | | | - Lin Shao
- Department of Neuroscience, Yale School of Medicine, New Haven, CT 06520
| | | | - Craig M Crews
- Department of Molecular, Cellular and Developmental Biology.,Department of Chemistry, Yale University, New Haven, CT 06511.,Department of Pharmacology, Yale University, New Haven, CT 06511
| |
Collapse
|
17
|
Vorberg IM. All the Same? The Secret Life of Prion Strains within Their Target Cells. Viruses 2019; 11:v11040334. [PMID: 30970585 DOI: 10.3390/v11040334] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 04/02/2019] [Accepted: 04/05/2019] [Indexed: 01/23/2023] Open
Abstract
Prions are infectious β-sheet-rich protein aggregates composed of misfolded prion protein (PrPSc) that do not possess coding nucleic acid. Prions replicate by recruiting and converting normal cellular PrPC into infectious isoforms. In the same host species, prion strains target distinct brain regions and cause different disease phenotypes. Prion strains are associated with biophysically distinct PrPSc conformers, suggesting that strain properties are enciphered within alternative PrPSc quaternary structures. So far it is unknown how prion strains target specific cells and initiate productive infections. Deeper mechanistic insight into the prion life cycle came from cell lines permissive to a range of different prion strains. Still, it is unknown why certain cell lines are refractory to infection by one strain but permissive to another. While pharmacologic and genetic manipulations revealed subcellular compartments involved in prion replication, little is known about strain-specific requirements for endocytic trafficking pathways. This review summarizes our knowledge on how prions replicate within their target cells and on strain-specific differences in prion cell biology.
Collapse
Affiliation(s)
- Ina M Vorberg
- German Center for Neurodegenerative Diseases (DZNE e.V.), Sigmund-Freud-Strasse 27, 53127 Bonn, Germany.
- Rheinische Friedrich-Wilhelms-Universität Bonn, 53127 Bonn, Germany.
| |
Collapse
|
18
|
Le NTT, Wu B, Harris DA. Prion neurotoxicity. Brain Pathol 2019; 29:263-277. [PMID: 30588688 DOI: 10.1111/bpa.12694] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 11/28/2018] [Indexed: 01/04/2023] Open
Abstract
Although the mechanisms underlying prion propagation and infectivity are now well established, the processes accounting for prion toxicity and pathogenesis have remained mysterious. These processes are of enormous clinical relevance as they hold the key to identification of new molecular targets for therapeutic intervention. In this review, we will discuss two broad areas of investigation relevant to understanding prion neurotoxicity. The first is the use of in vitro experimental systems that model key events in prion pathogenesis. In this context, we will describe a hippocampal neuronal culture system we developed that reproduces the earliest pathological alterations in synaptic morphology and function in response to PrPSc . This system has allowed us to define a core synaptotoxic signaling pathway involving the activation of NMDA and AMPA receptors, stimulation of p38 MAPK phosphorylation and collapse of the actin cytoskeleton in dendritic spines. The second area concerns a striking and unexpected phenomenon in which certain structural manipulations of the PrPC molecule itself, including introduction of N-terminal deletion mutations or binding of antibodies to C-terminal epitopes, unleash powerful toxic effects in cultured cells and transgenic mice. We will describe our studies of this phenomenon, which led to the recognition that it is related to the induction of large, abnormal ionic currents by the structurally altered PrP molecules. Our results suggest a model in which the flexible N-terminal domain of PrPC serves as a toxic effector which is regulated by intramolecular interactions with the globular C-terminal domain. Taken together, these two areas of study have provided important clues to underlying cellular and molecular mechanisms of prion neurotoxicity. Nevertheless, much remains to be done on this next frontier of prion science.
Collapse
Affiliation(s)
- Nhat T T Le
- Department of Biochemistry, Boston University School of Medicine, Boston, MA
| | - Bei Wu
- Department of Biochemistry, Boston University School of Medicine, Boston, MA
| | - David A Harris
- Department of Biochemistry, Boston University School of Medicine, Boston, MA
| |
Collapse
|
19
|
Jiang B, Liu J, Lee MH. Targeting a Designer TIMP-1 to the Cell Surface for Effective MT1-MMP Inhibition: A Potential Role for the Prion Protein in Renal Carcinoma Therapy. Molecules 2019; 24:molecules24020255. [PMID: 30641935 PMCID: PMC6359047 DOI: 10.3390/molecules24020255] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 01/03/2019] [Accepted: 01/07/2019] [Indexed: 12/16/2022] Open
Abstract
Renal carcinoma cells express Membrane Type 1-Matrix Metalloproteinase (MT1-MMP, MMP-14) to degrade extracellular matrix components and a range of bioactive molecules to allow metastasis and cell proliferation. The activity of MT1-MMP is modulated by the endogenous inhibitors, Tissue Inhibitor of Metalloproteinases (TIMPs). In this study, we describe a novel strategy that would enable a "designer" TIMP-1 tailored specifically for MT1-MMP inhibition (V4A/P6V/T98L; Kiapp 1.66 nM) to be targeted to the plasma membrane for more effective MT1-MMP inhibition. To achieve this, we fuse the designer TIMP-1 to the glycosyl-phosphatidyl inositol (GPI) anchor of the prion protein to create a membrane-tethered, high-affinity TIMP variant named "T1Pr αMT1" that is predominantly located on the cell surface and co-localised with MT1-MMP. Confocal microscopy shows that T1Pr αMT1 is found throughout the cell surface in particular the membrane ruffles where MT1-MMP is most abundant. Expression of T1Pr αMT1 brings about a complete abrogation of the gelatinolytic activity of cellular MT1-MMP in HT1080 fibrosarcoma cells whilst in renal carcinoma cells CaKi-1, the GPI-TIMP causes a disruption in MMP-mediated proteolysis of ECM components such as fibronectin, collagen I and laminin that consequently triggers a downstream senescence response. Moreover, the transduced cells also suffer from an impairment in proliferation and survival in vitro as well as in NOD/SCID mouse xenograft. Taken together, our findings demonstrate that the GPI anchor of prion could be exploited as a targeting device in TIMP engineering for MT1-MMP inhibition with a potential in renal carcinoma therapy.
Collapse
Affiliation(s)
- Bingjie Jiang
- Department of Biological Sciences, Xian Jiaotong Liverpool University, 111 Ren Ai Road, Suzhou 215123, China.
| | - Jian Liu
- Department of Biological Sciences, Xian Jiaotong Liverpool University, 111 Ren Ai Road, Suzhou 215123, China.
| | - Meng Huee Lee
- Department of Biological Sciences, Xian Jiaotong Liverpool University, 111 Ren Ai Road, Suzhou 215123, China.
| |
Collapse
|
20
|
Bartoletti-Stella A, Corrado P, Mometto N, Baiardi S, Durrenberger PF, Arzberger T, Reynolds R, Kretzschmar H, Capellari S, Parchi P. Analysis of RNA Expression Profiles Identifies Dysregulated Vesicle Trafficking Pathways in Creutzfeldt-Jakob Disease. Mol Neurobiol 2018; 56:5009-5024. [PMID: 30446946 DOI: 10.1007/s12035-018-1421-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 11/01/2018] [Indexed: 12/21/2022]
Abstract
Functional genomics applied to the study of RNA expression profiles identified several abnormal molecular processes in experimental prion disease. However, only a few similar studies have been carried out to date in a naturally occurring human prion disease. To better characterize the transcriptional cascades associated with sporadic Creutzfeldt-Jakob disease (sCJD), the most common human prion disease, we investigated the global gene expression profile in samples from the frontal cortex of 10 patients with sCJD and 10 non-neurological controls by microarray analysis. The comparison identified 333 highly differentially expressed genes (hDEGs) in sCJD. Functional enrichment Gene Ontology analysis revealed that hDEGs were mainly associated with synaptic transmission, including GABA (q value = 0.049) and glutamate (q value = 0.005) signaling, and the immune/inflammatory response. Furthermore, the analysis of cellular components performed on hDEGs showed a compromised regulation of vesicle-mediated transport with mainly up-regulated genes related to the endosome (q value = 0.01), lysosome (q value = 0.04), and extracellular exosome (q value < 0.01). A targeted analysis of the retromer core component VPS35 (vacuolar protein sorting-associated protein 35) showed a down-regulation of gene expression (p value= 0.006) and reduced brain protein levels (p value= 0.002). Taken together, these results confirm and expand previous microarray expression profile data in sCJD. Most significantly, they also demonstrate the involvement of the endosomal-lysosomal system. Since the latter is a common pathogenic pathway linking together diseases, such as Alzheimer's and Parkinson's, it might be the focus of future studies aimed to identify new therapeutic targets in neurodegenerative diseases.
Collapse
Affiliation(s)
- Anna Bartoletti-Stella
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Ospedale Bellaria, 40139, Bologna, Italy
| | - Patrizia Corrado
- Department of Biomedical and NeuroMotor Sciences, DIBINEM, University of Bologna, 40123, Bologna, Italy
| | - Nicola Mometto
- Department of Biomedical and NeuroMotor Sciences, DIBINEM, University of Bologna, 40123, Bologna, Italy
| | - Simone Baiardi
- Department of Biomedical and NeuroMotor Sciences, DIBINEM, University of Bologna, 40123, Bologna, Italy
| | - Pascal F Durrenberger
- Centre for Inflammation and Tissue Repair, UCL Respiratory, University College London, Rayne Building, London, UK
| | - Thomas Arzberger
- Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-University Munich, Munich, Germany.,Center for Neuropathology and Prion Research, Ludwig-Maximilians-University Munich, Munich, Germany
| | | | - Hans Kretzschmar
- Center for Neuropathology and Prion Research, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Sabina Capellari
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Ospedale Bellaria, 40139, Bologna, Italy. .,Department of Biomedical and NeuroMotor Sciences, DIBINEM, University of Bologna, 40123, Bologna, Italy.
| | - Piero Parchi
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Ospedale Bellaria, 40139, Bologna, Italy. .,Department of Experimental, Diagnostic and Specialty Medicine, DIMES, University of Bologna, 40138, Bologna, Italy.
| |
Collapse
|
21
|
Abstract
The development of multiple cell culture models of prion infection over the last two decades has led to a significant increase in our understanding of how prions infect cells. In particular, new techniques to distinguish exogenous from endogenous prions have allowed us for the first time to look in depth at the earliest stages of prion infection through to the establishment of persistent infection. These studies have shown that prions can infect multiple cell types, both neuronal and nonneuronal. Once in contact with the cell, they are rapidly taken up via multiple endocytic pathways. After uptake, the initial replication of prions occurs almost immediately on the plasma membrane and within multiple endocytic compartments. Following this acute stage of prion replication, persistent prion infection may or may not be established. Establishment of a persistent prion infection in cells appears to depend upon the achievement of a delicate balance between the rate of prion replication and degradation, the rate of cell division, and the efficiency of prion spread from cell to cell. Overall, cell culture models have shown that prion infection of the cell is a complex and variable process which can involve multiple cellular pathways and compartments even within a single cell.
Collapse
Affiliation(s)
- Suzette A Priola
- Laboratory of Persistent Viral Diseases, National Institute of Allergy and Infectious Diseases, Hamilton, MT, United States.
| |
Collapse
|
22
|
Retrograde Transport by Clathrin-Coated Vesicles is Involved in Intracellular Transport of PrP Sc in Persistently Prion-Infected Cells. Sci Rep 2018; 8:12241. [PMID: 30115966 PMCID: PMC6095914 DOI: 10.1038/s41598-018-30775-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 08/03/2018] [Indexed: 12/22/2022] Open
Abstract
Intracellular dynamics of an abnormal isoform of prion protein (PrPSc) are tightly associated with prion propagation. However, the machineries involved in the intracellular trafficking of PrPSc are not fully understood. Our previous study suggested that PrPSc in persistently prion-infected cells dynamically circulates between endocytic-recycling compartments (ERCs) and peripheral regions of the cells. To investigate these machineries, we focused on retrograde transport from endosomes to the trans-Golgi network, which is one of the pathways involved in recycling of molecules. PrPSc was co-localized with components of clathrin-coated vesicles (CCVs) as well as those of the retromer complex, which are known as machineries for retrograde transport. Fractionation of intracellular compartments by density gradient centrifugation showed the presence of PrPSc and the components of CCVs in the same fractions. Furthermore, PrPSc was detected in CCVs isolated from intracellular compartments of prion-infected cells. Knockdown of clathrin interactor 1, which is one of the clathrin adaptor proteins involved in retrograde transport, did not change the amount of PrPSc, but it altered the distribution of PrPSc from ERCs to peripheral regions, including late endosomes/lysosomes. These data demonstrated that some PrPSc is transported from endosomes to ERCs by CCVs, which might be involved in the recycling of PrPSc.
Collapse
|
23
|
Collu F, Spiga E, Chakroun N, Rezaei H, Fraternali F. Probing the early stages of prion protein (PrP) aggregation with atomistic molecular dynamics simulations. Chem Commun (Camb) 2018; 54:8007-8010. [PMID: 29967919 DOI: 10.1039/c8cc04089c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Prions are self-replicating infectious proteinaceous agents whose conformations are capable of forming amyloid-like aggregate fibrils. Here we present molecular dynamics simulations aimed at investigating the aggregation process of the β-rich H2H3 domain of the ovine prion protein (H2H3-OvPrPSc), known to be the portion of prion protein carrying oligomerization activity.
Collapse
Affiliation(s)
- Francesca Collu
- King's College London, Randall Centre for Cell & Molecular Biophysics, London, UK.
| | | | | | | | | |
Collapse
|
24
|
Phadwal K, Kurian D, Salamat MKF, MacRae VE, Diack AB, Manson JC. Spermine increases acetylation of tubulins and facilitates autophagic degradation of prion aggregates. Sci Rep 2018; 8:10004. [PMID: 29968775 PMCID: PMC6030104 DOI: 10.1038/s41598-018-28296-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 06/18/2018] [Indexed: 12/30/2022] Open
Abstract
Autolysosomal dysfunction and unstable microtubules are hallmarks of chronic neurodegenerative diseases associated with misfolded proteins. Investigation of impaired protein quality control and clearance systems could therefore provide an important avenue for intervention. To investigate this we have used a highly controlled model for protein aggregation, an in vitro prion system. Here we report that prion aggregates traffic via autolysosomes in the cytoplasm. Treatment with the natural polyamine spermine clears aggregates by enhancing autolysosomal flux. We demonstrated this by blocking the formation of mature autophagosomes resulting in accumulation of prion aggregates in the cytoplasm. Further we investigated the mechanism of spermine’s mode of action and we demonstrate that spermine increases the acetylation of microtubules, which is known to facilitate retrograde transport of autophagosomes from the cellular periphery to lysosomes located near the nucleus. We further report that spermine facilitates selective autophagic degradation of prion aggregates by binding to microtubule protein Tubb6. This is the first report in which spermine and the pathways regulated by it are applied as a novel approach towards clearance of misfolded prion protein and we suggest that this may have important implication for the broader family of protein misfolding diseases.
Collapse
Affiliation(s)
- Kanchan Phadwal
- The Roslin Institute & R(D)SVS, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Dominic Kurian
- The Roslin Institute & R(D)SVS, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | | | - Vicky E MacRae
- The Roslin Institute & R(D)SVS, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Abigail B Diack
- The Roslin Institute & R(D)SVS, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Jean C Manson
- The Roslin Institute & R(D)SVS, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK. .,Centre for Dementia Prevention, University of Edinburgh, Edinburgh, UK. .,Edinburgh Neuroscience, University of Edinburgh, Edinburgh, UK.
| |
Collapse
|
25
|
Vilette D, Courte J, Peyrin JM, Coudert L, Schaeffer L, Andréoletti O, Leblanc P. Cellular mechanisms responsible for cell-to-cell spreading of prions. Cell Mol Life Sci 2018; 75:2557-2574. [PMID: 29761205 PMCID: PMC11105574 DOI: 10.1007/s00018-018-2823-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 04/04/2018] [Accepted: 04/23/2018] [Indexed: 01/01/2023]
Abstract
Prions are infectious agents that cause fatal neurodegenerative diseases. Current evidence indicates that they are essentially composed of an abnormally folded protein (PrPSc). These abnormal aggregated PrPSc species multiply in infected cells by recruiting and converting the host PrPC protein into new PrPSc. How prions move from cell to cell and progressively spread across the infected tissue is of crucial importance and may provide experimental opportunity to delay the progression of the disease. In infected cells, different mechanisms have been identified, including release of infectious extracellular vesicles and intercellular transfer of PrPSc-containing organelles through tunneling nanotubes. These findings should allow manipulation of the intracellular trafficking events targeting PrPSc in these particular subcellular compartments to experimentally address the relative contribution of these mechanisms to in vivo prion pathogenesis. In addition, such information may prompt further experimental strategies to decipher the causal roles of protein misfolding and aggregation in other human neurodegenerative diseases.
Collapse
Affiliation(s)
- Didier Vilette
- UMR1225, INRA, ENVT, Ecole Nationale Vétérinaire, 23 Chemin des Capelles, Toulouse, France.
| | - Josquin Courte
- Neurosciences Paris Seine, UMR8246, Inserm U1130, IBPS, UPMC, Sorbonne Universités, 4 Place Jussieu, 75005, Paris, France
- Laboratoire Physico Chimie Curie, UMR168, UPMC, IPGG, Sorbonne Universités, 6 Rue Jean Calvin, 75005, Paris, France
| | - Jean Michel Peyrin
- Neurosciences Paris Seine, UMR8246, Inserm U1130, IBPS, UPMC, Sorbonne Universités, 4 Place Jussieu, 75005, Paris, France.
| | - Laurent Coudert
- Insitut NeuroMyoGène, CNRS UMR5310, INSERM U1217, Faculté de Médecine Rockefeller, Université Claude Bernard Lyon I, 8 Avenue Rockefeller, 69373, Lyon Cedex 08, France
| | - Laurent Schaeffer
- Insitut NeuroMyoGène, CNRS UMR5310, INSERM U1217, Faculté de Médecine Rockefeller, Université Claude Bernard Lyon I, 8 Avenue Rockefeller, 69373, Lyon Cedex 08, France
| | - Olivier Andréoletti
- UMR1225, INRA, ENVT, Ecole Nationale Vétérinaire, 23 Chemin des Capelles, Toulouse, France
| | - Pascal Leblanc
- Insitut NeuroMyoGène, CNRS UMR5310, INSERM U1217, Faculté de Médecine Rockefeller, Université Claude Bernard Lyon I, 8 Avenue Rockefeller, 69373, Lyon Cedex 08, France.
| |
Collapse
|
26
|
Abstract
During the course of prion infection, the normally soluble and protease-sensitive mammalian prion protein (PrPC) is refolded into an insoluble, partially protease-resistant, and infectious form called PrPSc. The conformational conversion of PrPC to PrPSc is a critical event during prion infection and is essential for the production of prion infectivity. This chapter briefly summarizes the ways in which cell biological approaches have enhanced our understanding of how PrP contributes to different aspects of prion pathogenesis.
Collapse
|
27
|
Mabbott NA. How do PrP Sc Prions Spread between Host Species, and within Hosts? Pathogens 2017; 6:pathogens6040060. [PMID: 29186791 PMCID: PMC5750584 DOI: 10.3390/pathogens6040060] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 11/16/2017] [Accepted: 11/21/2017] [Indexed: 12/22/2022] Open
Abstract
Prion diseases are sub-acute neurodegenerative diseases that affect humans and some domestic and free-ranging animals. Infectious prion agents are considered to comprise solely of abnormally folded isoforms of the cellular prion protein known as PrPSc. Pathology during prion disease is restricted to the central nervous system where it causes extensive neurodegeneration and ultimately leads to the death of the host. The first half of this review provides a thorough account of our understanding of the various ways in which PrPSc prions may spread between individuals within a population, both horizontally and vertically. Many natural prion diseases are acquired peripherally, such as by oral exposure, lesions to skin or mucous membranes, and possibly also via the nasal cavity. Following peripheral exposure, some prions accumulate to high levels within the secondary lymphoid organs as they make their journey from the site of infection to the brain, a process termed neuroinvasion. The replication of PrPSc prions within secondary lymphoid organs is important for their efficient spread to the brain. The second half of this review describes the key tissues, cells and molecules which are involved in the propagation of PrPSc prions from peripheral sites of exposure (such as the lumen of the intestine) to the brain. This section also considers how additional factors such as inflammation and aging might influence prion disease susceptibility.
Collapse
Affiliation(s)
- Neil A Mabbott
- The Roslin Institute & Royal (Dick) School of Veterinary Sciences, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, UK
| |
Collapse
|
28
|
Sakaguchi S, Uchiyama K. Novel amplification mechanism of prions through disrupting sortilin-mediated trafficking. Prion 2017; 11:398-404. [PMID: 29099278 DOI: 10.1080/19336896.2017.1391435] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
Conformational conversion of the cellular prion protein, PrPC, into the abnormally folded isoform of prion protein, PrPSc, which leads to marked accumulation of PrPSc in brains, is a key pathogenic event in prion diseases, a group of fatal neurodegenerative disorders caused by prions. However, the exact mechanism of PrPSc accumulation in prion-infected neurons remains unknown. We recently reported a novel cellular mechanism to support PrPSc accumulation in prion-infected neurons, in which PrPSc itself promotes its accumulation by evading the cellular inhibitory mechanism, which is newly identified in our recent study. We showed that the VPS10P sorting receptor sortilin negatively regulates PrPSc accumulation in prion-infected neurons, by interacting with PrPC and PrPSc and trafficking them to lysosomes for degradation. However, PrPSc stimulated lysosomal degradation of sortilin, disrupting the sortilin-mediated degradation of PrPC and PrPSc and eventually evoking further accumulation of PrPSc in prion-infected neurons. These findings suggest a positive feedback amplification mechanism for PrPSc accumulation in prion-infected neurons.
Collapse
Affiliation(s)
- Suehiro Sakaguchi
- a Division of Molecular Neurobiology, Institute for Enzyme Research (KOSOKEN), Tokushima University , Tokushima , Japan
| | - Keiji Uchiyama
- a Division of Molecular Neurobiology, Institute for Enzyme Research (KOSOKEN), Tokushima University , Tokushima , Japan
| |
Collapse
|
29
|
Shah SZA, Zhao D, Hussain T, Yang L. Role of the AMPK pathway in promoting autophagic flux via modulating mitochondrial dynamics in neurodegenerative diseases: Insight into prion diseases. Ageing Res Rev 2017; 40:51-63. [PMID: 28903070 DOI: 10.1016/j.arr.2017.09.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Revised: 09/06/2017] [Accepted: 09/07/2017] [Indexed: 12/15/2022]
Abstract
Neurons are highly energy demanding cells dependent on the mitochondrial oxidative phosphorylation system. Mitochondria generate energy via respiratory complexes that constitute the electron transport chain. Adenosine triphosphate depletion or glucose starvation act as a trigger for the activation of adenosine monophosphate-activated protein kinase (AMPK). AMPK is an evolutionarily conserved protein that plays an important role in cell survival and organismal longevity through modulation of energy homeostasis and autophagy. Several studies suggest that AMPK activation may improve energy metabolism and protein clearance in the brains of patients with vascular injury or neurodegenerative disease. Mild mitochondrial dysfunction leads to activated AMPK signaling, but severe endoplasmic reticulum stress and mitochondrial dysfunction may lead to a shift from autophagy towards apoptosis and perturbed AMPK signaling. Hence, controlling mitochondrial dynamics and autophagic flux via AMPK activation might be a useful therapeutic strategy in neurodegenerative diseases to reinstate energy homeostasis and degrade misfolded proteins. In this review article, we discuss briefly the role of AMPK signaling in energy homeostasis, the structure of AMPK, activation mechanisms of AMPK, regulation of AMPK, the role of AMPK in autophagy, the role of AMPK in neurodegenerative diseases, and finally the role of autophagic flux in prion diseases.
Collapse
Affiliation(s)
- Syed Zahid Ali Shah
- National Animal Transmissible Spongiform Encephalopathy Laboratory and Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - Deming Zhao
- National Animal Transmissible Spongiform Encephalopathy Laboratory and Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - Tariq Hussain
- National Animal Transmissible Spongiform Encephalopathy Laboratory and Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China
| | - Lifeng Yang
- National Animal Transmissible Spongiform Encephalopathy Laboratory and Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China.
| |
Collapse
|
30
|
Abstract
Three decades after the discovery of prions as the cause of Creutzfeldt-Jakob disease and other transmissible spongiform encephalopathies, we are still nowhere close to finding an effective therapy. Numerous pharmacological interventions have attempted to target various stages of disease progression, yet none has significantly ameliorated the course of disease. We still lack a mechanistic understanding of how the prions damage the brain, and this situation results in a dearth of validated pharmacological targets. In this review, we discuss the attempts to interfere with the replication of prions and to enhance their clearance. We also trace some of the possibilities to identify novel targets that may arise with increasing insights into prion biology.
Collapse
Affiliation(s)
- Adriano Aguzzi
- Institute of Neuropathology, University of Zurich, CH-8091 Zürich, Switzerland;
| | - Asvin K K Lakkaraju
- Institute of Neuropathology, University of Zurich, CH-8091 Zürich, Switzerland;
| | - Karl Frontzek
- Institute of Neuropathology, University of Zurich, CH-8091 Zürich, Switzerland;
| |
Collapse
|
31
|
Fehlinger A, Wolf H, Hossinger A, Duernberger Y, Pleschka C, Riemschoss K, Liu S, Bester R, Paulsen L, Priola SA, Groschup MH, Schätzl HM, Vorberg IM. Prion strains depend on different endocytic routes for productive infection. Sci Rep 2017; 7:6923. [PMID: 28761068 PMCID: PMC5537368 DOI: 10.1038/s41598-017-07260-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 06/27/2017] [Indexed: 01/08/2023] Open
Abstract
Prions are unconventional agents composed of misfolded prion protein that cause fatal neurodegenerative diseases in mammals. Prion strains induce specific neuropathological changes in selected brain areas. The mechanism of strain-specific cell tropism is unknown. We hypothesised that prion strains rely on different endocytic routes to invade and replicate within their target cells. Using prion permissive cells, we determined how impairment of endocytosis affects productive infection by prion strains 22L and RML. We demonstrate that early and late stages of prion infection are differentially sensitive to perturbation of clathrin- and caveolin-mediated endocytosis. Manipulation of canonical endocytic pathways only slightly influenced prion uptake. However, blocking the same routes had drastic strain-specific consequences on the establishment of infection. Our data argue that prion strains use different endocytic pathways for infection and suggest that cell type-dependent differences in prion uptake could contribute to host cell tropism.
Collapse
Affiliation(s)
- Andrea Fehlinger
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - Hanna Wolf
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - André Hossinger
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - Yvonne Duernberger
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - Catharina Pleschka
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - Katrin Riemschoss
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - Shu Liu
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - Romina Bester
- Institut für Virologie, Technische Universität München, Trogerstr. 30, 81675, München, Germany
| | - Lydia Paulsen
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - Suzette A Priola
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 South 4th Street, Hamilton, MT, 59840, USA
| | - Martin H Groschup
- Friedrich-Loeffler-Institut, Institute of Novel and Emerging Infectious Diseases, 17493, Greifswald-Insel Riems, Germany
| | - Hermann M Schätzl
- Dept. of Comparative Biology & Experimental Medicine, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Ina M Vorberg
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany. .,Department of Neurology, Rheinische Friedrich-Wilhelms-Universität, 53127, Bonn, Germany.
| |
Collapse
|
32
|
Uchiyama K, Tomita M, Yano M, Chida J, Hara H, Das NR, Nykjaer A, Sakaguchi S. Prions amplify through degradation of the VPS10P sorting receptor sortilin. PLoS Pathog 2017; 13:e1006470. [PMID: 28665987 PMCID: PMC5509376 DOI: 10.1371/journal.ppat.1006470] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 07/13/2017] [Accepted: 06/14/2017] [Indexed: 01/09/2023] Open
Abstract
Prion diseases are a group of fatal neurodegenerative disorders caused by prions, which consist mainly of the abnormally folded isoform of prion protein, PrPSc. A pivotal pathogenic event in prion disease is progressive accumulation of prions, or PrPSc, in brains through constitutive conformational conversion of the cellular prion protein, PrPC, into PrPSc. However, the cellular mechanism by which PrPSc is progressively accumulated in prion-infected neurons remains unknown. Here, we show that PrPSc is progressively accumulated in prion-infected cells through degradation of the VPS10P sorting receptor sortilin. We first show that sortilin interacts with PrPC and PrPSc and sorts them to lysosomes for degradation. Consistently, sortilin-knockdown increased PrPSc accumulation in prion-infected cells. In contrast, overexpression of sortilin reduced PrPSc accumulation in prion-infected cells. These results indicate that sortilin negatively regulates PrPSc accumulation in prion-infected cells. The negative role of sortilin in PrPSc accumulation was further confirmed in sortilin-knockout mice infected with prions. The infected mice had accelerated prion disease with early accumulation of PrPSc in their brains. Interestingly, sortilin was reduced in prion-infected cells and mouse brains. Treatment of prion-infected cells with lysosomal inhibitors, but not proteasomal inhibitors, increased the levels of sortilin. Moreover, sortilin was reduced following PrPSc becoming detectable in cells after infection with prions. These results indicate that PrPSc accumulation stimulates sortilin degradation in lysosomes. Taken together, these results show that PrPSc accumulation of itself could impair the sortilin-mediated sorting of PrPC and PrPSc to lysosomes for degradation by stimulating lysosomal degradation of sortilin, eventually leading to progressive accumulation of PrPSc in prion-infected cells. Once prions consisting mainly of PrPSc infect hosts, they constitutively propagate in their brains. Progressive production of PrPSc through the constitutive conformational conversion of PrPC into PrPSc underlies prion propagation. However, the mechanism enabling progressive production of PrPSc in prion-infected cells remains unknown. We here found that the VPS10P sorting receptor sortilin is involved in degradation of PrPC and PrPSc in infected cells by binding to both molecules and subsequently trafficking them to the lysosomal protein degradation pathway. Interestingly, we also found that degradation of sortilin was stimulated in lysosomes in prion-infected cells possibly as a result of the sortilin-PrPC or -PrPSc complexes being trafficked to lysosomes. Our findings indicate that PrPSc itself impairs the sortilin-mediated degradation of PrPC and PrPSc by stimulating degradation of sortilin in lysosomes. This eventually results in progressive production of PrPSc in prion-infected cells by increasing the opportunity of PrPC to convert into PrPSc and by accumulating the already produced PrPSc. This mechanism was confirmed in sortilin-KO mice infected with prions. The mice had exacerbated prion disease with earlier accumulation of PrPSc in their brains.
Collapse
Affiliation(s)
- Keiji Uchiyama
- Division of Molecular Neurobiology, Institute for Enzyme Research (KOSOKEN), Tokushima University, Tokushima, Japan
- * E-mail: (SS); (KU)
| | - Mitsuru Tomita
- Division of Molecular Neurobiology, Institute for Enzyme Research (KOSOKEN), Tokushima University, Tokushima, Japan
- Student Laboratory, Faculty of Medicine, Tokushima University, Tokushima, Japan
| | - Masashi Yano
- Division of Molecular Neurobiology, Institute for Enzyme Research (KOSOKEN), Tokushima University, Tokushima, Japan
| | - Junji Chida
- Division of Molecular Neurobiology, Institute for Enzyme Research (KOSOKEN), Tokushima University, Tokushima, Japan
| | - Hideyuki Hara
- Division of Molecular Neurobiology, Institute for Enzyme Research (KOSOKEN), Tokushima University, Tokushima, Japan
| | - Nandita Rani Das
- Division of Molecular Neurobiology, Institute for Enzyme Research (KOSOKEN), Tokushima University, Tokushima, Japan
| | - Anders Nykjaer
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Suehiro Sakaguchi
- Division of Molecular Neurobiology, Institute for Enzyme Research (KOSOKEN), Tokushima University, Tokushima, Japan
- * E-mail: (SS); (KU)
| |
Collapse
|
33
|
Majumder P, Chakrabarti O. Lysosomal Quality Control in Prion Diseases. Mol Neurobiol 2017; 55:2631-2644. [PMID: 28421536 DOI: 10.1007/s12035-017-0512-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 04/04/2017] [Indexed: 11/28/2022]
Abstract
Prion diseases are transmissible, familial or sporadic. The prion protein (PrP), a normal cell surface glycoprotein, is ubiquitously expressed throughout the body. While loss of function of PrP does not elicit apparent phenotypes, generation of misfolded forms of the protein or its aberrant metabolic isoforms has been implicated in a number of neurodegenerative disorders such as scrapie, kuru, Creutzfeldt-Jakob disease, fatal familial insomnia, Gerstmann-Sträussler-Scheinker and bovine spongiform encephalopathy. These diseases are all phenotypically characterised by spongiform vacuolation of the adult brain, hence collectively termed as late-onset spongiform neurodegeneration. Misfolded form of PrP (PrPSc) and one of its abnormal metabolic isoforms (the transmembrane CtmPrP) are known to be disease-causing agents that lead to progressive loss of structure or function of neurons culminating in neuronal death. The aberrant forms of PrP utilise and manipulate the various intracellular quality control mechanisms during pathogenesis of these diseases. Amongst these, the lysosomal quality control machinery emerges as one of the primary targets exploited by the disease-causing isoforms of PrP. The autophagosomal-lysosomal degradation pathway is adversely affected in multiple ways in prion diseases and may hence be regarded as an important modulator of neurodegeneration. Some of the ESCRT pathway proteins have also been shown to be involved in the manifestation of disease phenotype. This review discusses the significance of the lysosomal quality control pathway in affecting transmissible and familial types of prion diseases.
Collapse
Affiliation(s)
- Priyanka Majumder
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Sector-1, Block-AF, Bidhannagar, Kolkata, West Bengal, 700064, India
| | - Oishee Chakrabarti
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Sector-1, Block-AF, Bidhannagar, Kolkata, West Bengal, 700064, India.
| |
Collapse
|
34
|
PrP Knockout Cells Expressing Transmembrane PrP Resist Prion Infection. J Virol 2017; 91:JVI.01686-16. [PMID: 27847358 DOI: 10.1128/jvi.01686-16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 11/01/2016] [Indexed: 11/20/2022] Open
Abstract
Glycosylphosphatidylinositol (GPI) anchoring of the prion protein (PrPC) influences PrPC misfolding into the disease-associated isoform, PrPres, as well as prion propagation and infectivity. GPI proteins are found in cholesterol- and sphingolipid-rich membrane regions called rafts. Exchanging the GPI anchor for a nonraft transmembrane sequence redirects PrPC away from rafts. Previous studies showed that nonraft transmembrane PrPC variants resist conversion to PrPres when transfected into scrapie-infected N2a neuroblastoma cells, likely due to segregation of transmembrane PrPC and GPI-anchored PrPres in distinct membrane environments. Thus, it remained unclear whether transmembrane PrPC might convert to PrPres if seeded by an exogenous source of PrPres not associated with host cell rafts and without the potential influence of endogenous expression of GPI-anchored PrPC To further explore these questions, constructs containing either a C-terminal wild-type GPI anchor signal sequence or a nonraft transmembrane sequence containing a flexible linker were expressed in a cell line derived from PrP knockout hippocampal neurons, NpL2. NpL2 cells have physiological similarities to primary neurons, representing a novel and advantageous model for studying transmissible spongiform encephalopathy (TSE) infection. Cells were infected with inocula from multiple prion strains and in different biochemical states (i.e., membrane bound as in brain microsomes from wild-type mice or purified GPI-anchorless amyloid fibrils). Only GPI-anchored PrPC supported persistent PrPres propagation. Our data provide strong evidence that in cell culture GPI anchor-directed membrane association of PrPC is required for persistent PrPres propagation, implicating raft microdomains as a location for conversion. IMPORTANCE Mechanisms of prion propagation, and what makes them transmissible, are poorly understood. Glycosylphosphatidylinositol (GPI) membrane anchoring of the prion protein (PrPC) directs it to specific regions of cell membranes called rafts. In order to test the importance of the raft environment on prion propagation, we developed a novel model for prion infection where cells expressing either GPI-anchored PrPC or transmembrane-anchored PrPC, which partitions it to a different location, were treated with infectious, misfolded forms of the prion protein, PrPres We show that only GPI-anchored PrPC was able to convert to PrPres and able to serially propagate. The results strongly suggest that GPI anchoring and the localization of PrPC to rafts are crucial to the ability of PrPC to propagate as a prion.
Collapse
|
35
|
Moon JH, Lee JH, Nazim UMD, Lee YJ, Seol JW, Eo SK, Lee JH, Park SY. Human prion protein-induced autophagy flux governs neuron cell damage in primary neuron cells. Oncotarget 2016; 7:29989-30002. [PMID: 27102156 PMCID: PMC5058658 DOI: 10.18632/oncotarget.8802] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2016] [Accepted: 04/13/2016] [Indexed: 01/09/2023] Open
Abstract
An unusual molecular structure of the prion protein, PrPsc is found only in mammals with transmissible prion diseases. Prion protein stands for either the infectious pathogen itself or a main component of it. Recent studies suggest that autophagy is one of the major functions that keep cells alive and has a protective effect against the neurodegeneration. In this study, we investigated that the effect of human prion protein on autophagy-lysosomal system of primary neuronal cells. The treatment of human prion protein induced primary neuron cell death and decreased both LC3-II and p62 protein amount indicating autophagy flux activation. Electron microscope pictures confirmed the autophagic flux activation in neuron cells treated with prion protein. Inhibition of autophagy flux using pharmacological and genetic tools prevented neuron cell death induced by human prion protein. Autophagy flux induced by prion protein is more activated in prpc expressing cells than in prpc silencing cells. These data demonstrated that prion protein-induced autophagy flux is involved in neuron cell death in prion disease and suggest that autophagy flux might play a critical role in neurodegenerative diseases including prion disease.
Collapse
Affiliation(s)
- Ji-Hong Moon
- Biosafety Research Institute, College of Veterinary Medicine, Chonbuk National University, Iksan, Jeonbuk, South Korea
| | - Ju-Hee Lee
- Biosafety Research Institute, College of Veterinary Medicine, Chonbuk National University, Iksan, Jeonbuk, South Korea
| | - Uddin MD Nazim
- Biosafety Research Institute, College of Veterinary Medicine, Chonbuk National University, Iksan, Jeonbuk, South Korea
| | - You-Jin Lee
- Biosafety Research Institute, College of Veterinary Medicine, Chonbuk National University, Iksan, Jeonbuk, South Korea
| | - Jae-Won Seol
- Biosafety Research Institute, College of Veterinary Medicine, Chonbuk National University, Iksan, Jeonbuk, South Korea
| | - Seong-Kug Eo
- Biosafety Research Institute, College of Veterinary Medicine, Chonbuk National University, Iksan, Jeonbuk, South Korea
| | - John-hwa Lee
- Biosafety Research Institute, College of Veterinary Medicine, Chonbuk National University, Iksan, Jeonbuk, South Korea
| | - Sang-Youel Park
- Biosafety Research Institute, College of Veterinary Medicine, Chonbuk National University, Iksan, Jeonbuk, South Korea
| |
Collapse
|
36
|
Glatzel M, Linsenmeier L, Dohler F, Krasemann S, Puig B, Altmeppen HC. Shedding light on prion disease. Prion 2016; 9:244-56. [PMID: 26186508 DOI: 10.1080/19336896.2015.1065371] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Proteolytic processing regulates key processes in health and disease. The cellular prion protein (PrP(C)) is subject to at least 3 cleavage events, α-cleavage, β-cleavage and shedding. In contrast to α- and β-cleavage where there is an ongoing controversy on the identity of relevant proteases, the metalloprotease ADAM10 represents the only relevant PrP sheddase. Here we focus on the roles that ADAM10-mediated shedding of PrP(C) and its pathogenic isoform (PrP(Sc)) might play in regulating their physiological and pathogenic functions, respectively. As revealed by our recent study using conditional ADAM10 knockout mice (Altmeppen et al., 2015), shedding of PrP seems to be involved in key processes of prion diseases. These aspects and several open questions arising from them are discussed. Increased knowledge on this topic can shed new light on prion diseases and other neurodegenerative conditions as well.
Collapse
Affiliation(s)
- Markus Glatzel
- a Institute of Neuropathology; University Medical Center Hamburg-Eppendorf ; Hamburg , Germany
| | | | | | | | | | | |
Collapse
|
37
|
McKinnon C, Goold R, Andre R, Devoy A, Ortega Z, Moonga J, Linehan JM, Brandner S, Lucas JJ, Collinge J, Tabrizi SJ. Prion-mediated neurodegeneration is associated with early impairment of the ubiquitin-proteasome system. Acta Neuropathol 2016; 131:411-25. [PMID: 26646779 PMCID: PMC4752964 DOI: 10.1007/s00401-015-1508-y] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 11/02/2015] [Accepted: 11/12/2015] [Indexed: 01/25/2023]
Abstract
Prion diseases are a group of fatal neurodegenerative disorders characterised by the accumulation of misfolded prion protein (PrP(Sc)) in the brain. The critical relationship between aberrant protein misfolding and neurotoxicity currently remains unclear. The accumulation of aggregation-prone proteins has been linked to impairment of the ubiquitin-proteasome system (UPS) in a variety of neurodegenerative disorders, including Alzheimer's, Parkinson's and Huntington's diseases. As the principal route for protein degradation in mammalian cells, this could have profound detrimental effects on neuronal function and survival. Here, we determine the temporal onset of UPS dysfunction in prion-infected Ub(G76V)-GFP reporter mice, which express a ubiquitin fusion proteasome substrate to measure in vivo UPS activity. We show that the onset of UPS dysfunction correlates closely with PrP(Sc) deposition, preceding earliest behavioural deficits and neuronal loss. UPS impairment was accompanied by accumulation of polyubiquitinated substrates and found to affect both neuronal and astrocytic cell populations. In prion-infected CAD5 cells, we demonstrate that activation of the UPS by the small molecule inhibitor IU1 is sufficient to induce clearance of polyubiquitinated substrates and reduce misfolded PrP(Sc) load. Taken together, these results identify the UPS as a possible early mediator of prion pathogenesis and promising target for development of future therapeutics.
Collapse
Affiliation(s)
- Chris McKinnon
- Department of Neurodegenerative Disease, University College London, Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Rob Goold
- Department of Neurodegenerative Disease, University College London, Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Ralph Andre
- Department of Neurodegenerative Disease, University College London, Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Anny Devoy
- Department of Neurodegenerative Disease, University College London, Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Zaira Ortega
- Centro de Biología Molecular "Severo Ochoa", (CBMSO) CSIC/UAM, Madrid, Spain
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Julie Moonga
- Department of Neurodegenerative Disease, University College London, Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Jacqueline M Linehan
- MRC Prion Unit, University College London, Institute of Neurology, Queen Square, London, UK
| | - Sebastian Brandner
- Department of Neurodegenerative Disease, University College London, Institute of Neurology, Queen Square, London, WC1N 3BG, UK
- Division of Neuropathology, The National Hospital for Neurology and Neurosurgery, Queen Square, London, UK
| | - José J Lucas
- Centro de Biología Molecular "Severo Ochoa", (CBMSO) CSIC/UAM, Madrid, Spain
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - John Collinge
- Department of Neurodegenerative Disease, University College London, Institute of Neurology, Queen Square, London, WC1N 3BG, UK
- MRC Prion Unit, University College London, Institute of Neurology, Queen Square, London, UK
| | - Sarah J Tabrizi
- Department of Neurodegenerative Disease, University College London, Institute of Neurology, Queen Square, London, WC1N 3BG, UK.
| |
Collapse
|
38
|
Muñoz-Gutiérrez JF, Aguilar Pierlé S, Schneider DA, Baszler TV, Stanton JB. Transcriptomic Determinants of Scrapie Prion Propagation in Cultured Ovine Microglia. PLoS One 2016; 11:e0147727. [PMID: 26807844 PMCID: PMC4726464 DOI: 10.1371/journal.pone.0147727] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 01/07/2016] [Indexed: 12/22/2022] Open
Abstract
Susceptibility to infection by prions is highly dependent on the amino acid sequence and host expression of the cellular prion protein (PrPC); however, cellular expression of a genetically susceptible PrPC is insufficient. As an example, it has been shown in cultured cells that permissive and resistant sublines derived from the same parental population often have similar expression levels of PrPC. Thus, additional cellular factors must influence susceptibility to prion infection. The aim of this study was to elucidate the factors associated with relative permissiveness and resistance to scrapie prions in cultured cells derived from a naturally affected species. Two closely related ovine microglia clones with different prion susceptibility, but no detectable differences in PrPC expression levels, were inoculated with either scrapie-positive or scrapie-negative sheep brainstem homogenates. Five passages post-inoculation, the transcriptional profiles of mock and infected clones were sequenced using Illumina technology. Comparative transcriptional analyses identified twenty-two differentially transcribed genes, most of which were upregulated in poorly permissive microglia. This included genes encoding for selenoprotein P, endolysosomal proteases, and proteins involved in extracellular matrix remodeling. Furthermore, in highly permissive microglia, transforming growth factor β–induced, retinoic acid receptor response 1, and phosphoserine aminotranspherase 1 gene transcripts were upregulated. Gene Set Enrichment Analysis identified proteolysis, translation, and mitosis as the most affected pathways and supported the upregulation trend of several genes encoding for intracellular proteases and ribosomal proteins in poorly permissive microglia. This study identifies new genes potentially involved in scrapie prion propagation, corroborates results from other studies, and extends those results into another cell culture model.
Collapse
Affiliation(s)
- Juan F. Muñoz-Gutiérrez
- Department of Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
- * E-mail: (JFMG); (JBS)
| | - Sebastián Aguilar Pierlé
- Department of Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
| | - David A. Schneider
- Department of Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
- United States Department of Agriculture, Agricultural Research Service, Pullman, Washington, United States of America
| | - Timothy V. Baszler
- Department of Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, Washington, United States of America
| | - James B. Stanton
- Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
- * E-mail: (JFMG); (JBS)
| |
Collapse
|
39
|
Milisav I, Šuput D, Ribarič S. Unfolded Protein Response and Macroautophagy in Alzheimer's, Parkinson's and Prion Diseases. Molecules 2015; 20:22718-56. [PMID: 26694349 PMCID: PMC6332363 DOI: 10.3390/molecules201219865] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 11/30/2015] [Accepted: 12/09/2015] [Indexed: 12/13/2022] Open
Abstract
Proteostasis are integrated biological pathways within cells that control synthesis, folding, trafficking and degradation of proteins. The absence of cell division makes brain proteostasis susceptible to age-related changes and neurodegeneration. Two key processes involved in sustaining normal brain proteostasis are the unfolded protein response and autophagy. Alzheimer’s disease (AD), Parkinson’s disease (PD) and prion diseases (PrDs) have different clinical manifestations of neurodegeneration, however, all share an accumulation of misfolded pathological proteins associated with perturbations in unfolded protein response and macroautophagy. While both the unfolded protein response and macroautophagy play an important role in the prevention and attenuation of AD and PD progression, only macroautophagy seems to play an important role in the development of PrDs. Macroautophagy and unfolded protein response can be modulated by pharmacological interventions. However, further research is necessary to better understand the regulatory pathways of both processes in health and neurodegeneration to be able to develop new therapeutic interventions.
Collapse
Affiliation(s)
- Irina Milisav
- Institute of Pathophysiology, Faculty of Medicine, Zaloška 4, Ljubljana SI-1000, Slovenia.
- Faculty of Health Sciences, Zdravstvena pot 5, SI-1000 Ljubljana, Slovenija.
| | - Dušan Šuput
- Institute of Pathophysiology, Faculty of Medicine, Zaloška 4, Ljubljana SI-1000, Slovenia.
| | - Samo Ribarič
- Institute of Pathophysiology, Faculty of Medicine, Zaloška 4, Ljubljana SI-1000, Slovenia.
| |
Collapse
|
40
|
Speldewinde SH, Doronina VA, Grant CM. Autophagy protects against de novo formation of the [PSI+] prion in yeast. Mol Biol Cell 2015; 26:4541-51. [PMID: 26490118 PMCID: PMC4678013 DOI: 10.1091/mbc.e15-08-0548] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 10/14/2015] [Indexed: 11/11/2022] Open
Abstract
The molecular basis by which prions arise spontaneously is poorly understood. The present data point toward oxidative protein damage as one of the triggers of de novo prion formation. Autophagy functions to clear oxidatively damaged proteins before their conversion to the prion form. Prions are self-propagating, infectious proteins that underlie several neurodegenerative diseases. The molecular basis underlying their sporadic formation is poorly understood. We show that autophagy protects against de novo formation of [PSI+], which is the prion form of the yeast Sup35 translation termination factor. Autophagy is a cellular degradation system, and preventing autophagy by mutating its core components elevates the frequency of spontaneous [PSI+] formation. Conversely, increasing autophagic flux by treating cells with the polyamine spermidine suppresses prion formation in mutants that normally show a high frequency of de novo prion formation. Autophagy also protects against the de novo formation of another prion, namely the Rnq1/[PIN+] prion, which is not related in sequence to the Sup35/[PSI+] prion. We show that growth under anaerobic conditions in the absence of molecular oxygen abrogates Sup35 protein damage and suppresses the high frequency of [PSI+] formation in an autophagy mutant. Autophagy therefore normally functions to remove oxidatively damaged Sup35, which accumulates in cells grown under aerobic conditions, but in the absence of autophagy, damaged/misfolded Sup35 undergoes structural transitions favoring its conversion to the propagatable [PSI+] form.
Collapse
Affiliation(s)
- Shaun H Speldewinde
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Victoria A Doronina
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
| | - Chris M Grant
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom
| |
Collapse
|
41
|
Aguzzi A, Lakkaraju AKK. Cell Biology of Prions and Prionoids: A Status Report. Trends Cell Biol 2015; 26:40-51. [PMID: 26455408 DOI: 10.1016/j.tcb.2015.08.007] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 08/08/2015] [Accepted: 08/24/2015] [Indexed: 11/18/2022]
Abstract
The coalescence of proteins into highly ordered aggregates is a hallmark of protein misfolding disorders (PMDs), which, when affecting the central nervous system, lead to progressive neurodegeneration. Although the chemical identity and the topology of each culprit protein are unique, the principles governing aggregation and propagation are strikingly stereotypical. It is now clear that such protein aggregates can spread from cell to cell and eventually affect entire organ systems - similarly to prion diseases. However, because most aggregates are not found to transmit between individuals, they are not infectious sensu strictiori. Therefore, they are not identical to prions and we prefer to define them as 'prionoids'. Here we review recent advances in understanding the toxicity of protein aggregation affecting the brain.
Collapse
Affiliation(s)
- Adriano Aguzzi
- Institute of Neuropathology, University of Zürich, CH-8091 Zürich, Switzerland.
| | - Asvin K K Lakkaraju
- Institute of Neuropathology, University of Zürich, CH-8091 Zürich, Switzerland.
| |
Collapse
|
42
|
Trafficking and degradation pathways in pathogenic conversion of prions and prion-like proteins in neurodegenerative diseases. Virus Res 2015; 207:146-54. [DOI: 10.1016/j.virusres.2015.01.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 10/01/2014] [Accepted: 01/22/2015] [Indexed: 11/20/2022]
|
43
|
Sisakhtnezhad S, Khosravi L. Emerging physiological and pathological implications of tunneling nanotubes formation between cells. Eur J Cell Biol 2015; 94:429-43. [PMID: 26164368 DOI: 10.1016/j.ejcb.2015.06.010] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 06/20/2015] [Accepted: 06/23/2015] [Indexed: 12/21/2022] Open
Abstract
Cell-to-cell communication is a critical requirement to coordinate behaviors of the cells in a community and thereby achieve tissue homeostasis and conservation of the multicellular organisms. Tunneling nanotubes (TNTs), as a cell-to-cell communication over long distance, allow for bi- or uni-directional transfer of cellular components between cells. Identification of inducing agents and the cell and molecular mechanism underling the formation of TNTs and their structural and functional features may lead to finding new important roles for these intercellular bridges in vivo and in vitro. During the last decade, research has shown TNTs have different structural and functional properties, varying between and within cell systems. In this review, we will focus on TNTs and their cell and molecular mechanism of formation. Moreover, the latest findings into their functional roles in physiological and pathological processes, such as signal transduction, micro and nano-particles delivery, immune responses, embryogenesis, cellular reprogramming, apoptosis, cancer, and neurodegenerative diseases initiation and progression and pathogens transfer, will be discussed.
Collapse
Affiliation(s)
| | - Leila Khosravi
- Department of Biology, Faculty of Science, Razi University, Kermanshah, Iran
| |
Collapse
|
44
|
Goold R, McKinnon C, Tabrizi SJ. Prion degradation pathways: Potential for therapeutic intervention. Mol Cell Neurosci 2015; 66:12-20. [PMID: 25584786 PMCID: PMC4503822 DOI: 10.1016/j.mcn.2014.12.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 12/16/2014] [Indexed: 12/18/2022] Open
Abstract
Prion diseases are fatal neurodegenerative disorders. Pathology is closely linked to the misfolding of native cellular PrP(C) into the disease-associated form PrP(Sc) that accumulates in the brain as disease progresses. Although treatments have yet to be developed, strategies aimed at stimulating the degradation of PrP(Sc) have shown efficacy in experimental models of prion disease. Here, we describe the cellular pathways that mediate PrP(Sc) degradation and review possible targets for therapeutic intervention. This article is part of a Special Issue entitled 'Neuronal Protein'.
Collapse
Affiliation(s)
- Rob Goold
- Department of Neurodegenerative Disease, UCL Institute of Neurology, University College London, United Kingdom
| | - Chris McKinnon
- Department of Neurodegenerative Disease, UCL Institute of Neurology, University College London, United Kingdom
| | - Sarah J Tabrizi
- Department of Neurodegenerative Disease, UCL Institute of Neurology, University College London, United Kingdom.
| |
Collapse
|
45
|
Abstract
The plasma membrane (PM) and endocytic protein quality control (QC) in conjunction with the endosomal sorting machinery either repairs or targets conformationally damaged membrane proteins for lysosomal/vacuolar degradation. Here, we provide an overview of emerging aspects of the underlying mechanisms of PM QC that fulfill a critical role in preserving cellular protein homeostasis in health and diseases.
Collapse
Affiliation(s)
- Pirjo M Apaja
- Department of Physiology and Research Group Focused on Protein Structure (GRASP), McGill University, Montreal, Quebec, Canada; and
| | - Gergely L Lukacs
- Department of Physiology and Research Group Focused on Protein Structure (GRASP), McGill University, Montreal, Quebec, Canada; and Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| |
Collapse
|
46
|
Puig B, Altmeppen H, Glatzel M. The GPI-anchoring of PrP: implications in sorting and pathogenesis. Prion 2015; 8:11-8. [PMID: 24509692 DOI: 10.4161/pri.27892] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The cellular prion protein (PrP(C)) is an N-glycosylated GPI-anchored protein usually present in lipid rafts with numerous putative functions. When it changes its conformation to a pathological isoform (then referred to as PrP(Sc)), it is an essential part of the prion, the agent causing fatal and transmissible neurodegenerative prion diseases. There is growing evidence that toxicity and neuronal damage on the one hand and propagation/infectivity on the other hand are two distinct processes of the disease and that the GPI-anchor attachment of PrP(C) and PrP(Sc) plays an important role in protein localization and in neurotoxicity. Here we review how the signal sequence of the GPI-anchor matters in PrP(C) localization, how an altered cellular localization of PrP(C) or differences in GPI-anchor composition can affect prion infection, and we discuss through which mechanisms changes on the anchorage of PrP(C) can modify the disease process.
Collapse
|
47
|
Yim YI, Park BC, Yadavalli R, Zhao X, Eisenberg E, Greene LE. The multivesicular body is the major internal site of prion conversion. J Cell Sci 2015; 128:1434-43. [PMID: 25663703 PMCID: PMC4379730 DOI: 10.1242/jcs.165472] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The conversion of the properly folded prion protein, PrPc, to its misfolded amyloid form, PrPsc, occurs as the two proteins traffic along the endocytic pathway and PrPc is exposed to PrPsc. To determine the specific site of prion conversion, we knocked down various proteins in the endocytic pathway including Rab7a, Tsg101 and Hrs (also known as HGS). PrPsc was markedly reduced in two chronically infected cell lines by preventing the maturation of the multivesicular body, a process that begins in the early endosome and ends with the sorting of cargo to the lysosome. By contrast, knocking down proteins in the retromer complex, which diverts cargo away from the multivesicular body caused an increase in PrPsc levels. These results suggest that the multivesicular body is the major site for intracellular conversion of PrPc to PrPsc.
Collapse
Affiliation(s)
- Yang-In Yim
- Laboratory of Cell Biology, NHLBI, NIH, Bethesda, MD 20892, USA
| | - Bum-Chan Park
- Laboratory of Cell Biology, NHLBI, NIH, Bethesda, MD 20892, USA
| | | | - Xiaohong Zhao
- Laboratory of Cell Biology, NHLBI, NIH, Bethesda, MD 20892, USA
| | - Evan Eisenberg
- Laboratory of Cell Biology, NHLBI, NIH, Bethesda, MD 20892, USA
| | - Lois E Greene
- Laboratory of Cell Biology, NHLBI, NIH, Bethesda, MD 20892, USA
| |
Collapse
|
48
|
Berman DE, Ringe D, Petsko GA, Small SA. The use of pharmacological retromer chaperones in Alzheimer's disease and other endosomal-related disorders. Neurotherapeutics 2015; 12:12-8. [PMID: 25472693 PMCID: PMC4322078 DOI: 10.1007/s13311-014-0321-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The retromer is an evolutionary conserved multiprotein complex involved in the sorting and retrograde trafficking of cargo from endosomal compartments to the Golgi network and to the cell surface. The neuronal retromer traffics the amyloid precursor protein away from the endosomes, a site where amyloid precursor protein is enzymatically cleaved into pathogenic fragments in Alzheimer's disease. In recent years, deficiencies in retromer-mediated transport have been implicated in several neurological and non-neurological diseases, including Parkinson's disease, suggesting that improving the efficacy of the retromer trafficking pathway would result in decreased pathology. We recently identified a new family of small molecules that appear to stabilize the interaction between members of the retromer complex and enhance its function in neurons: the retromer pharmacological chaperones. Here we discuss the role of these molecules in the improvement of retromer trafficking and endosomal dysfunction, as well as their potential as therapeutics for neurological and non-neurological disorders.
Collapse
Affiliation(s)
- Diego E Berman
- The Taub Institute for Research on Alzheimer's Disease and the Aging Brain, and Department of Pathology and Cell Biology, Columbia University College of Physicians and Surgeons, New York, NY, 10032, USA,
| | | | | | | |
Collapse
|
49
|
Le NTT, Narkiewicz J, Aulić S, Salzano G, Tran HT, Scaini D, Moda F, Giachin G, Legname G. Synthetic prions and other human neurodegenerative proteinopathies. Virus Res 2014; 207:25-37. [PMID: 25449570 DOI: 10.1016/j.virusres.2014.10.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 10/02/2014] [Accepted: 10/22/2014] [Indexed: 12/13/2022]
Abstract
Transmissible spongiform encephalopathies (TSE) are a heterogeneous group of neurodegenerative disorders. The common feature of these diseases is the pathological conversion of the normal cellular prion protein (PrP(C)) into a β-structure-rich conformer-termed PrP(Sc). The latter can induce a self-perpetuating process leading to amplification and spreading of pathological protein assemblies. Much evidence suggests that PrP(Sc) itself is able to recruit and misfold PrP(C) into the pathological conformation. Recent data have shown that recombinant PrP(C) can be misfolded in vitro and the resulting synthetic conformers are able to induce the conversion of PrP(C) into PrP(Sc)in vivo. In this review we describe the state-of-the-art of the body of literature in this field. In addition, we describe a cell-based assay to test synthetic prions in cells, providing further evidence that synthetic amyloids are able to template conversion of PrP into prion inclusions. Studying prions might help to understand the pathological mechanisms governing other neurodegenerative diseases. Aggregation and deposition of misfolded proteins is a common feature of several neurodegenerative disorders, such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and other disorders. Although the proteins implicated in each of these diseases differ, they share a common prion mechanism. Recombinant proteins are able to aggregate in vitro into β-rich amyloid fibrils, sharing some features of the aggregates found in the brain. Several studies have reported that intracerebral inoculation of synthetic aggregates lead to unique pathology, which spread progressively to distal brain regions and reduced survival time in animals. Here, we review the prion-like features of different proteins involved in neurodegenerative disorders, such as α-synuclein, superoxide dismutase-1, amyloid-β and tau.
Collapse
Affiliation(s)
- Nhat Tran Thanh Le
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Joanna Narkiewicz
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Suzana Aulić
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Giulia Salzano
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Hoa Thanh Tran
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Denis Scaini
- Life Science Department, University of Trieste, Trieste, Italy
| | - Fabio Moda
- Carlo Besta Neurological Institute, Department of Neuropathology and Neurology 5, Milan, Italy
| | - Gabriele Giachin
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy.
| | - Giuseppe Legname
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy; Elettra-Sincrotrone Trieste S.C.p.A., Area Science Park, Basovizza, Trieste, Italy.
| |
Collapse
|
50
|
Prion protein-specific antibodies-development, modes of action and therapeutics application. Viruses 2014; 6:3719-37. [PMID: 25275428 PMCID: PMC4213558 DOI: 10.3390/v6103719] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 09/22/2014] [Accepted: 09/23/2014] [Indexed: 12/21/2022] Open
Abstract
Prion diseases or Transmissible Spongiform Encephalopathies (TSEs) are lethal neurodegenerative disorders involving the misfolding of the host encoded cellular prion protein, PrPC. This physiological form of the protein is expressed throughout the body, and it reaches the highest levels in the central nervous system where the pathology occurs. The conversion into the pathogenic isoform denoted as prion or PrPSc is the key event in prion disorders. Prominent candidates for the treatment of prion diseases are antibodies and their derivatives. Anti-PrPC antibodies are able to clear PrPSc from cell culture of infected cells. Furthermore, application of anti-PrPC antibodies suppresses prion replication in experimental animal models. Major drawbacks of immunotherapy are immune tolerance, the risks of neurotoxic side effects, limited ability of compounds to cross the blood-brain barrier and their unfavorable pharmacokinetic. The focus of this review is to recapitulate the current understanding of the molecular mechanisms for antibody mediated anti-prion activity. Although relevant for designing immunotherapeutic tools, the characterization of key antibody parameters shaping the molecular mechanism of the PrPC to PrPSc conversion remains elusive. Moreover, this review illustrates the various attempts towards the development of anti-PrP antibody compounds and discusses therapeutic candidates that modulate PrP expression.
Collapse
|