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Kell DB, Pretorius E. Are fibrinaloid microclots a cause of autoimmunity in Long Covid and other post-infection diseases? Biochem J 2023; 480:1217-1240. [PMID: 37584410 DOI: 10.1042/bcj20230241] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 08/03/2023] [Accepted: 08/07/2023] [Indexed: 08/17/2023]
Abstract
It is now well established that the blood-clotting protein fibrinogen can polymerise into an anomalous form of fibrin that is amyloid in character; the resultant clots and microclots entrap many other molecules, stain with fluorogenic amyloid stains, are rather resistant to fibrinolysis, can block up microcapillaries, are implicated in a variety of diseases including Long COVID, and have been referred to as fibrinaloids. A necessary corollary of this anomalous polymerisation is the generation of novel epitopes in proteins that would normally be seen as 'self', and otherwise immunologically silent. The precise conformation of the resulting fibrinaloid clots (that, as with prions and classical amyloid proteins, can adopt multiple, stable conformations) must depend on the existing small molecules and metal ions that the fibrinogen may (and is some cases is known to) have bound before polymerisation. Any such novel epitopes, however, are likely to lead to the generation of autoantibodies. A convergent phenomenology, including distinct conformations and seeding of the anomalous form for initiation and propagation, is emerging to link knowledge in prions, prionoids, amyloids and now fibrinaloids. We here summarise the evidence for the above reasoning, which has substantial implications for our understanding of the genesis of autoimmunity (and the possible prevention thereof) based on the primary process of fibrinaloid formation.
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Affiliation(s)
- Douglas B Kell
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, U.K
- The Novo Nordisk Foundation Centre for Biosustainability, Technical University of Denmark, Kemitorvet 200, 2800 Kgs Lyngby, Denmark
- Department of Physiological Sciences, Faculty of Science, Stellenbosch University, Private Bag X1 Matieland, Stellenbosch 7602, South Africa
| | - Etheresia Pretorius
- Department of Biochemistry, Cell and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, U.K
- Department of Physiological Sciences, Faculty of Science, Stellenbosch University, Private Bag X1 Matieland, Stellenbosch 7602, South Africa
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Restelli E, Capone V, Pozzoli M, Ortolan D, Quaglio E, Corbelli A, Fiordaliso F, Beznoussenko GV, Artuso V, Roiter I, Sallese M, Chiesa R. Activation of Src family kinase ameliorates secretory trafficking in mutant prion protein cells. J Biol Chem 2021; 296:100490. [PMID: 33662396 PMCID: PMC8059059 DOI: 10.1016/j.jbc.2021.100490] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 02/04/2021] [Accepted: 02/26/2021] [Indexed: 11/25/2022] Open
Abstract
Fatal familial insomnia (FFI), genetic Creutzfeldt-Jakob disease (gCJD), and Gerstmann-Sträussler-Scheinker (GSS) syndrome are neurodegenerative disorders linked to prion protein (PrP) mutations. The pathogenic mechanisms are not known, but increasing evidence points to mutant PrP misfolding and retention in the secretory pathway. We previously found that the D178N/M129 mutation associated with FFI accumulates in the Golgi of neuronal cells, impairing post-Golgi trafficking. In this study we further characterized the trafficking defect induced by the FFI mutation and tested the 178N/V129 variant linked to gCJD and a nine-octapeptide repeat insertion associated with GSS. We used transfected HeLa cells, embryonic fibroblasts and primary neurons from transgenic mice, and fibroblasts from carriers of the FFI mutation. In all these cell types, the mutant PrPs showed abnormal intracellular localizations, accumulating in the endoplasmic reticulum (ER) and Golgi. To test the efficiency of the membrane trafficking system, we monitored the intracellular transport of the temperature-sensitive vesicular stomatite virus glycoprotein (VSV-G), a well-established cargo reporter, and of endogenous procollagen I (PC-I). We observed marked alterations in secretory trafficking, with VSV-G accumulating mainly in the Golgi complex and PC-I in the ER and Golgi. A redacted version of mutant PrP with reduced propensity to misfold did not impair VSV-G trafficking, nor did artificial ER or Golgi retention of wild-type PrP; this indicates that both misfolding and intracellular retention were required to induce the transport defect. Pharmacological activation of Src family kinase (SFK) improved intracellular transport, suggesting that mutant PrP impairs secretory trafficking through corruption of SFK-mediated signaling.
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Affiliation(s)
- Elena Restelli
- Laboratory of Prion Neurobiology, Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Vanessa Capone
- Department of Innovative Technologies in Medicine & Dentistry, University G. D'Annunzio, Chieti, Italy; Center for Advanced Studies and Technology (CAST), University G. D'Annunzio, Chieti, Italy
| | - Manuela Pozzoli
- Laboratory of Prion Neurobiology, Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Davide Ortolan
- Laboratory of Prion Neurobiology, Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Elena Quaglio
- Laboratory of Prion Neurobiology, Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Alessandro Corbelli
- Bio-Imaging Unit, Department of Cardiovascular Medicine, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | - Fabio Fiordaliso
- Bio-Imaging Unit, Department of Cardiovascular Medicine, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy
| | | | | | - Ignazio Roiter
- ULSS 2 Marca Trevigiana, Ca' Foncello Hospital, Treviso, Italy
| | - Michele Sallese
- Department of Innovative Technologies in Medicine & Dentistry, University G. D'Annunzio, Chieti, Italy; Center for Advanced Studies and Technology (CAST), University G. D'Annunzio, Chieti, Italy
| | - Roberto Chiesa
- Laboratory of Prion Neurobiology, Department of Neuroscience, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Milan, Italy.
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Mutant prion proteins increase calcium permeability of AMPA receptors, exacerbating excitotoxicity. PLoS Pathog 2020; 16:e1008654. [PMID: 32673372 PMCID: PMC7365390 DOI: 10.1371/journal.ppat.1008654] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Accepted: 05/26/2020] [Indexed: 01/26/2023] Open
Abstract
Prion protein (PrP) mutations are linked to genetic prion diseases, a class of phenotypically heterogeneous neurodegenerative disorders with invariably fatal outcome. How mutant PrP triggers neurodegeneration is not known. Synaptic dysfunction precedes neuronal loss but it is not clear whether, and through which mechanisms, disruption of synaptic activity ultimately leads to neuronal death. Here we show that mutant PrP impairs the secretory trafficking of AMPA receptors (AMPARs). Specifically, intracellular retention of the GluA2 subunit results in synaptic exposure of GluA2-lacking, calcium-permeable AMPARs, leading to increased calcium permeability and enhanced sensitivity to excitotoxic cell death. Mutant PrPs linked to different genetic prion diseases affect AMPAR trafficking and function in different ways. Our findings identify AMPARs as pathogenic targets in genetic prion diseases, and support the involvement of excitotoxicity in neurodegeneration. They also suggest a mechanistic explanation for how different mutant PrPs may cause distinct disease phenotypes. Genetic prion diseases are degenerative brain disorders caused by mutations in the gene encoding the prion protein (PrP). Different PrP mutations cause different diseases, including Creutzfeldt-Jakob disease, fatal familial insomnia and Gerstmann-Sträussler-Scheinker syndrome. How mutant PrP causes neuronal death and how different mutants encode distinct disease phenotypes is not known. Here we show that mutant PrP alters the subunit composition of glutamate AMPA receptors, promoting cell surface exposure of GluA2-lacking, calcium-permeable receptors, ultimately increasing neuronal vulnerability to excitotoxic cell death. We also demonstrate that the underlying molecular mechanism is the formation of a GluA2 subunit-PrP complex which is retained in the neuronal secretory pathway. PrP mutants associated with clinically different genetic prion diseases have distinct effects on GluA2 trafficking, depending on their tendency to misfold and aggregate in different intracellular organelles, indicating a possible contribution of this mechanism to the disease phenotype.
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Abstract
Fatal familial insomnia (FFI) and sporadic fatal insomnia (sFI), or thalamic form of sporadic Creutzfeldt-Jakob disease MM2 (sCJDMM2T), are prion diseases originally named and characterized in 1992 and 1999, respectively. FFI is genetically determined and linked to a D178N mutation coupled with the M129 genotype in the prion protein gene (PRNP) at chromosome 20. sFI is a phenocopy of FFI and likely its sporadic form. Both diseases are primarily characterized by progressive sleep impairment, disturbances of autonomic nervous system, and motor signs associated with severe loss of nerve cells in medial thalamic nuclei. Both diseases harbor an abnormal disease-associated prion protein isoform, resistant to proteases with relative mass of 19 kDa identified as resPrPTSE type 2. To date at least 70 kindreds affected by FFI with 198 members and 18 unrelated carriers along with 25 typical cases of sFI have been published. The D178N-129M mutation is thought to cause FFI by destabilizing the mutated prion protein and facilitating its conversion to PrPTSE. The thalamus is the brain region first affected. A similar mechanism triggered spontaneously may underlie sFI.
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Chiesa R, Restelli E, Comerio L, Del Gallo F, Imeri L. Transgenic mice recapitulate the phenotypic heterogeneity of genetic prion diseases without developing prion infectivity: Role of intracellular PrP retention in neurotoxicity. Prion 2017; 10:93-102. [PMID: 26864450 PMCID: PMC4981194 DOI: 10.1080/19336896.2016.1139276] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Genetic prion diseases are degenerative brain disorders caused by mutations in the gene encoding the prion protein (PrP). Different PrP mutations cause different diseases, including Creutzfeldt-Jakob disease (CJD), Gerstmann-Sträussler-Scheinker (GSS) syndrome and fatal familial insomnia (FFI). The reason for this variability is not known. It has been suggested that prion strains with unique self-replicating and neurotoxic properties emerge spontaneously in individuals carrying PrP mutations, dictating the phenotypic expression of disease. We generated transgenic mice expressing the FFI mutation, and found that they developed a fatal neurological illness highly reminiscent of FFI, and different from those of similarly generated mice modeling genetic CJD and GSS. Thus transgenic mice recapitulate the phenotypic differences seen in humans. The mutant PrPs expressed in these mice are misfolded but unable to self-replicate. They accumulate in different compartments of the neuronal secretory pathway, impairing the membrane delivery of ion channels essential for neuronal function. Our results indicate that conversion of mutant PrP into an infectious isoform is not required for pathogenesis, and suggest that the phenotypic variability may be due to different effects of mutant PrP on intracellular transport.
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Affiliation(s)
- Roberto Chiesa
- a Laboratory of Prion Neurobiology, Department of Neuroscience, IRCCS - "Mario Negri" Institute for Pharmacological Research , Milan , Italy
| | - Elena Restelli
- a Laboratory of Prion Neurobiology, Department of Neuroscience, IRCCS - "Mario Negri" Institute for Pharmacological Research , Milan , Italy
| | - Liliana Comerio
- a Laboratory of Prion Neurobiology, Department of Neuroscience, IRCCS - "Mario Negri" Institute for Pharmacological Research , Milan , Italy
| | - Federico Del Gallo
- b Department of Health Sciences , University of Milan Medical School , Milan , Italy
| | - Luca Imeri
- b Department of Health Sciences , University of Milan Medical School , Milan , Italy
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Llorens F, Zarranz JJ, Fischer A, Zerr I, Ferrer I. Fatal Familial Insomnia: Clinical Aspects and Molecular Alterations. Curr Neurol Neurosci Rep 2017; 17:30. [PMID: 28324299 DOI: 10.1007/s11910-017-0743-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
PURPOSE OF REVIEW Fatal familiar insomnia (FFI) is an autosomal dominant inherited prion disease caused by D178N mutation in the prion protein gene (PRNP D178N) accompanied by the presence of a methionine at the codon 129 polymorphic site on the mutated allele. FFI is characterized by severe sleep disorder, dysautonomia, motor signs and abnormal behaviour together with primary atrophy of selected thalamic nuclei and inferior olives, and expansion to other brain regions with disease progression. This article reviews recent research on the clinical and molecular aspects of the disease. RECENT FINDINGS New clinical and biomarker tools have been implemented in order to assist in the diagnosis of the disease. In addition, the generation of mouse models, the availability of 'omics' data in brain tissue and the use of new seeding techniques shed light on the molecular events in FFI pathogenesis. Biochemical studies in human samples also reveal that neuropathological alterations in vulnerable brain regions underlie severe impairment in key cellular processes such as mitochondrial and protein synthesis machinery. Although the development of a therapy is still a major challenge, recent findings represent a step toward understanding of the clinical and molecular aspects of FFI.
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Affiliation(s)
- Franc Llorens
- Department of Neurology, Clinical Dementia Center, University Medical Center, Georg-August University, Robert Koch Strasse 40, Göttingen, Germany. .,German Center for Neurodegenerative Diseases (DZNE)-site Göttingen, Göttingen, Germany.
| | - Juan-José Zarranz
- Neurology Department, University Hospital Cruces, University of the Basque Country, Bilbao, Bizkaia, Spain
| | - Andre Fischer
- German Center for Neurodegenerative Diseases (DZNE)-site Göttingen, Göttingen, Germany
| | - Inga Zerr
- Department of Neurology, Clinical Dementia Center, University Medical Center, Georg-August University, Robert Koch Strasse 40, Göttingen, Germany.,German Center for Neurodegenerative Diseases (DZNE)-site Göttingen, Göttingen, Germany
| | - Isidro Ferrer
- Institute of Neuropathology, Bellvitge University Hospital-IDIBELL, L'Hospitalet de Llobregat, c/Feixa Llarga sn, 08907, Barcelona, Spain. .,University of Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain. .,CIBERNED (Network Centre for Biomedical Research of Neurodegenerative Diseases), Institute Carlos III, Ministry of Health, Madrid, Spain.
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Stincardini C, Massignan T, Biggi S, Elezgarai SR, Sangiovanni V, Vanni I, Pancher M, Adami V, Moreno J, Stravalaci M, Maietta G, Gobbi M, Negro A, Requena JR, Castilla J, Nonno R, Biasini E. An antipsychotic drug exerts anti-prion effects by altering the localization of the cellular prion protein. PLoS One 2017; 12:e0182589. [PMID: 28787011 PMCID: PMC5546605 DOI: 10.1371/journal.pone.0182589] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 07/20/2017] [Indexed: 02/01/2023] Open
Abstract
Prion diseases are neurodegenerative conditions characterized by the conformational conversion of the cellular prion protein (PrPC), an endogenous membrane glycoprotein of uncertain function, into PrPSc, a pathological isoform that replicates by imposing its abnormal folding onto PrPC molecules. A great deal of evidence supports the notion that PrPC plays at least two roles in prion diseases, by acting as a substrate for PrPSc replication, and as a mediator of its toxicity. This conclusion was recently supported by data suggesting that PrPC may transduce neurotoxic signals elicited by other disease-associated protein aggregates. Thus, PrPC may represent a convenient pharmacological target for prion diseases, and possibly other neurodegenerative conditions. Here, we sought to characterize the activity of chlorpromazine (CPZ), an antipsychotic previously shown to inhibit prion replication by directly binding to PrPC. By employing biochemical and biophysical techniques, we provide direct experimental evidence indicating that CPZ does not bind PrPC at biologically relevant concentrations. Instead, the compound exerts anti-prion effects by inducing the relocalization of PrPC from the plasma membrane. Consistent with these findings, CPZ also inhibits the cytotoxic effects delivered by a PrP mutant. Interestingly, we found that the different pharmacological effects of CPZ could be mimicked by two inhibitors of the GTPase activity of dynamins, a class of proteins involved in the scission of newly formed membrane vesicles, and recently reported as potential pharmacological targets of CPZ. Collectively, our results redefine the mechanism by which CPZ exerts anti-prion effects, and support a primary role for dynamins in the membrane recycling of PrPC, as well as in the propagation of infectious prions.
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Affiliation(s)
- Claudia Stincardini
- Dulbecco Telethon Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Tania Massignan
- Dulbecco Telethon Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Silvia Biggi
- Dulbecco Telethon Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Saioa R. Elezgarai
- Dulbecco Telethon Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, Trento, Italy
- Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Valeria Sangiovanni
- Dulbecco Telethon Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Ilaria Vanni
- Department of Food Safety and Veterinary Health, Istituto Superiore di Sanitá, Rome, Italy
| | - Michael Pancher
- HTS Core Facility, Centre for Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Valentina Adami
- HTS Core Facility, Centre for Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Jorge Moreno
- CIC bioGUNE, Parque tecnológico de Bizkaia, Derio
| | - Matteo Stravalaci
- Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Giulia Maietta
- Dulbecco Telethon Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, Trento, Italy
| | - Marco Gobbi
- Department of Molecular Biochemistry and Pharmacology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
| | - Alessandro Negro
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Jesús R. Requena
- CIMUS Biomedical Research Institute, University of Santiago de Compostela, Santiago de Compostela, Spain
- Department of Medical Sciences, University of Santiago de Compostela, Santiago de Compostela, Spain
| | - Joaquín Castilla
- CIC bioGUNE, Parque tecnológico de Bizkaia, Derio
- IKERBASQUE, Basque Foundation for Science, Bilbao, Bizkaia, Spain
| | - Romolo Nonno
- Department of Food Safety and Veterinary Health, Istituto Superiore di Sanitá, Rome, Italy
| | - Emiliano Biasini
- Dulbecco Telethon Laboratory of Prions and Amyloids, Centre for Integrative Biology (CIBIO), University of Trento, Trento, Italy
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy
- * E-mail:
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Lenis YY, Wang X, Tang W, Wu G, Bazer FW. Effects of agmatine on secretion of interferon tau and catecholamines and expression of genes related to production of polyamines by ovine trophectoderm cells. Amino Acids 2016; 48:2389-99. [DOI: 10.1007/s00726-016-2216-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 03/09/2016] [Indexed: 02/03/2023]
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Bouybayoune I, Mantovani S, Del Gallo F, Bertani I, Restelli E, Comerio L, Tapella L, Baracchi F, Fernández-Borges N, Mangieri M, Bisighini C, Beznoussenko GV, Paladini A, Balducci C, Micotti E, Forloni G, Castilla J, Fiordaliso F, Tagliavini F, Imeri L, Chiesa R. Transgenic fatal familial insomnia mice indicate prion infectivity-independent mechanisms of pathogenesis and phenotypic expression of disease. PLoS Pathog 2015; 11:e1004796. [PMID: 25880443 PMCID: PMC4400166 DOI: 10.1371/journal.ppat.1004796] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 03/09/2015] [Indexed: 11/18/2022] Open
Abstract
Fatal familial insomnia (FFI) and a genetic form of Creutzfeldt-Jakob disease (CJD178) are clinically different prion disorders linked to the D178N prion protein (PrP) mutation. The disease phenotype is determined by the 129 M/V polymorphism on the mutant allele, which is thought to influence D178N PrP misfolding, leading to the formation of distinctive prion strains with specific neurotoxic properties. However, the mechanism by which misfolded variants of mutant PrP cause different diseases is not known. We generated transgenic (Tg) mice expressing the mouse PrP homolog of the FFI mutation. These mice synthesize a misfolded form of mutant PrP in their brains and develop a neurological illness with severe sleep disruption, highly reminiscent of FFI and different from that of analogously generated Tg(CJD) mice modeling CJD178. No prion infectivity was detectable in Tg(FFI) and Tg(CJD) brains by bioassay or protein misfolding cyclic amplification, indicating that mutant PrP has disease-encoding properties that do not depend on its ability to propagate its misfolded conformation. Tg(FFI) and Tg(CJD) neurons have different patterns of intracellular PrP accumulation associated with distinct morphological abnormalities of the endoplasmic reticulum and Golgi, suggesting that mutation-specific alterations of secretory transport may contribute to the disease phenotype. Genetic prion diseases are degenerative brain disorders caused by mutations in the gene encoding the prion protein (PrP). Different PrP mutations cause different diseases, including Creutzfeldt-Jakob disease (CJD) and fatal familial insomnia (FFI). The reason for this variability is not known, but assembly of the mutant PrPs into distinct aggregates that spread in the brain by promoting PrP aggregation may contribute to the disease phenotype. We previously generated transgenic mice modeling genetic CJD, clinically identified by dementia and motor abnormalities. We have now generated transgenic mice carrying the PrP mutation associated with FFI, and found that they develop severe sleep abnormalities and other key features of the human disorder. Thus, transgenic mice recapitulate the phenotypic differences seen in humans. The mutant PrPs in FFI and CJD mice are aggregated but unable to promote PrP aggregation. They accumulate in different intracellular compartments and cause distinct morphological abnormalities of transport organelles. These results indicate that mutant PrP has disease-encoding properties that are independent of its ability to self-propagate, and suggest that the phenotypic heterogeneity may be due to different effects of aggregated PrP on intracellular transport. Our study provides new insights into the mechanisms of selective neuronal dysfunction due to protein aggregation.
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Affiliation(s)
- Ihssane Bouybayoune
- Department of Neuroscience, IRCCS—“Mario Negri” Institute for Pharmacological Research, Milan, Italy
| | - Susanna Mantovani
- Department of Neuroscience, IRCCS—“Mario Negri” Institute for Pharmacological Research, Milan, Italy
| | - Federico Del Gallo
- Department of Health Sciences, University of Milan Medical School, Milan, Italy
| | - Ilaria Bertani
- Department of Neuroscience, IRCCS—“Mario Negri” Institute for Pharmacological Research, Milan, Italy
| | - Elena Restelli
- Department of Neuroscience, IRCCS—“Mario Negri” Institute for Pharmacological Research, Milan, Italy
| | - Liliana Comerio
- Department of Neuroscience, IRCCS—“Mario Negri” Institute for Pharmacological Research, Milan, Italy
| | - Laura Tapella
- Department of Neuroscience, IRCCS—“Mario Negri” Institute for Pharmacological Research, Milan, Italy
| | - Francesca Baracchi
- Department of Health Sciences, University of Milan Medical School, Milan, Italy
| | | | - Michela Mangieri
- Division of Neuropathology and Neurology, IRCCS Foundation “Carlo Besta” National Neurological Institute, Milan, Italy
| | - Cinzia Bisighini
- Bio-Imaging Unit, Department of Cardiovascular Research, IRCCS—“Mario Negri” Institute for Pharmacological Research, Milan, Italy
| | | | - Alessandra Paladini
- Department of Neuroscience, IRCCS—“Mario Negri” Institute for Pharmacological Research, Milan, Italy
| | - Claudia Balducci
- Department of Neuroscience, IRCCS—“Mario Negri” Institute for Pharmacological Research, Milan, Italy
| | - Edoardo Micotti
- Department of Neuroscience, IRCCS—“Mario Negri” Institute for Pharmacological Research, Milan, Italy
| | - Gianluigi Forloni
- Department of Neuroscience, IRCCS—“Mario Negri” Institute for Pharmacological Research, Milan, Italy
| | - Joaquín Castilla
- CIC bioGUNE, Parque Tecnológico de Bizkaia, Derio, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Fabio Fiordaliso
- Bio-Imaging Unit, Department of Cardiovascular Research, IRCCS—“Mario Negri” Institute for Pharmacological Research, Milan, Italy
| | - Fabrizio Tagliavini
- Division of Neuropathology and Neurology, IRCCS Foundation “Carlo Besta” National Neurological Institute, Milan, Italy
| | - Luca Imeri
- Department of Health Sciences, University of Milan Medical School, Milan, Italy
| | - Roberto Chiesa
- Department of Neuroscience, IRCCS—“Mario Negri” Institute for Pharmacological Research, Milan, Italy
- * E-mail:
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Wang X, Burghardt RC, Romero JJ, Hansen TR, Wu G, Bazer FW. Functional roles of arginine during the peri-implantation period of pregnancy. III. Arginine stimulates proliferation and interferon tau production by ovine trophectoderm cells via nitric oxide and polyamine-TSC2-MTOR signaling pathways. Biol Reprod 2015; 92:75. [PMID: 25653279 DOI: 10.1095/biolreprod.114.125989] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
In mammal species, arginine is a multifunctional amino acid required for survival, growth, and development of conceptuses (embryo/fetus and associated extraembryonic membranes) during the peri-implantation period of pregnancy. However, functional roles of arginine with respect to it being a substrate for production of nitric oxide (NO) and polyamines on trophectoderm cell proliferation and function remain largely unknown. To systematically assess roles of arginine in conceptus development and its effect on interferon tau (IFNT) production for pregnancy recognition signaling in ruminants, an established ovine trophectoderm (oTr1) cell line isolated from Day-15 ovine conceptuses were used to determine their response to arginine, putrescine, and NO donors, as well as their associated inhibitors. Arginine at physiological concentration (0.2 mM) stimulated maximum oTr cell proliferation (increased 2.0-fold at 48 h and 2.6-fold at 96 h; P < 0.05), stimulated IFNT production (IFNT/cell increased 3.1-fold; P < 0.05), and increased total protein per cell by more than 1.5-fold (P < 0.05). It also increased phosphorylated tuberous sclerosis protein (p-TSC2) and phosphorylated mechanistic target of rapamycin (MTOR) abundance by more than 2.7- and 4.3-fold (P < 0.0001) after long-term incubation, respectively. When Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME; NO synthase inhibitor), DL-α-difluoromethylornithine hydrochloride hydrate (DFMO; ornithine decarboxylase inhibitor), and the combination (L-NAME + DFMO) were added, the effects of arginine on cell proliferation was reduced by 10.7%, 16.1%, and 22.3% (P < 0.05) at 48 h, and 15.3%, 27.2%, and 39.1% (P < 0.05) at 96 h of incubation, respectively, but values remained 1.5-fold higher (P < 0.05) than for the arginine-free control, which suggests that arginine, per se, serves as a growth factor. Both putrescine and NO stimulate cell proliferation via activation of the TSC2-MTOR signaling cascade, whereas only putrescine increased IFNT production. Collectively, our results indicate that arginine is essential for oTr1 cell proliferation and IFNT production via the NO/polyamine-TSC2-MTOR signaling pathways, particularly the pathway involving polyamine biosynthesis.
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Affiliation(s)
- Xiaoqiu Wang
- Center for Animal Biotechnology and Genomics, Texas A&M University, College Station, Texas Department of Animal Science, Texas A&M University, College Station, Texas
| | - Robert C Burghardt
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas
| | - Jared J Romero
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Thomas R Hansen
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Guoyao Wu
- Center for Animal Biotechnology and Genomics, Texas A&M University, College Station, Texas Department of Animal Science, Texas A&M University, College Station, Texas
| | - Fuller W Bazer
- Center for Animal Biotechnology and Genomics, Texas A&M University, College Station, Texas Department of Animal Science, Texas A&M University, College Station, Texas
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Synaptic dysfunction in prion diseases: a trafficking problem? Int J Cell Biol 2013; 2013:543803. [PMID: 24369467 PMCID: PMC3863542 DOI: 10.1155/2013/543803] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 10/08/2013] [Indexed: 11/26/2022] Open
Abstract
Synaptic dysfunction is an important cause of neurological symptoms in prion diseases, a class of clinically heterogeneous neurodegenerative disorders caused by misfolding of the cellular prion protein (PrPC). Experimental data suggest that accumulation of misfolded PrPC in the endoplasmic reticulum (ER) may be crucial in synaptic failure, possibly because of the activation of the translational repression pathway of the unfolded protein response. Here, we report that this pathway is not operative in mouse models of genetic prion disease, consistent with our previous observation that ER stress is not involved. Building on our recent finding that ER retention of mutant PrPC impairs the secretory trafficking of calcium channels essential for synaptic function, we propose a model of pathogenicity in which intracellular retention of misfolded PrPC results in loss of function or gain of toxicity of PrPC-interacting proteins. This neurotoxic modality may also explain the phenotypic heterogeneity of prion diseases.
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