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Pollock NM, Leighton P, Neil G, Allison WT. Transcriptomic analysis of zebrafish prion protein mutants supports conserved cross-species function of the cellular prion protein. Prion 2021; 15:70-81. [PMID: 34139950 PMCID: PMC8216189 DOI: 10.1080/19336896.2021.1924557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/23/2021] [Accepted: 04/27/2021] [Indexed: 10/31/2022] Open
Abstract
Cellular Prion Protein (PrPC) is a well-studied protein as the substrate for various progressive untreatable neurodegenerative diseases. Normal functions of PrPC are poorly understood, though recent proteomic and transcriptomic approaches have begun to reveal common themes. We use our compound prp1 and prp2 knockout mutant zebrafish at three days post fertilization to take a transcriptomic approach to investigating potentially conserved PrPC functions during development. Gene ontology analysis shows the biological processes with the largest changes in gene expression include redox processing, transport and cell adhesion. Within these categories several different gene families were prevalent including the solute carrier proteins, cytochrome p450 enzymes and protocadherins. Continuing from previous studies identifying cell adhesion as an important function of PrPC we found that in addition to the protocadherins there was a significant reduction in transcript abundance of both ncam1a and st8sia2. These two genes are involved in the early development of vertebrates. The alterations in cell adhesion transcripts were consistent with past findings in zebrafish and mouse prion protein mutants; however E-cadherin processing after prion protein knockdown failed to reveal any differences compared with wild type in either our double prp1/prp2 mutant fish or after prp1 morpholino knockdown. Our data supports a cross species conserved role for PrPC in the development and maintenance of the central nervous system, particularly by regulating various and important cell adhesion processes.
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Affiliation(s)
- Niall Mungo Pollock
- Department of Biological Sciences, University of Alberta, Edmonton, Canada
- Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton, Canada
| | - Patricia Leighton
- Department of Biological Sciences, University of Alberta, Edmonton, Canada
- Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton, Canada
| | - Gavin Neil
- Department of Biological Sciences, University of Alberta, Edmonton, Canada
| | - W. Ted Allison
- Department of Biological Sciences, University of Alberta, Edmonton, Canada
- Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton, Canada
- Department of Medical Genetics, University of Alberta, Edmonton, Canada
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Brandhorst D, Parnaud G, Friberg A, Lavallard V, Demuylder-Mischler S, Hughes S, Saphörster J, Kurfürst M, Korsgren O, Berney T, Johnson PRV. Multicenter Assessment of Animal-free Collagenase AF-1 for Human Islet Isolation. Cell Transplant 2018; 26:1688-1693. [PMID: 29251107 PMCID: PMC5753983 DOI: 10.1177/0963689717731574] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Animal-free (AF) SERVA Collagenase AF-1 and Neutral Protease (NP) AF GMP Grade have recently become available for human islet isolation. This report describes the initial experiences of 3 different islet transplant centers. Thirty-four human pancreases were digested using 1 vial of the 6 different lots of Collagenase AF-1 (2,000–2,583 PZ-U/vial) supplemented with 4 different lots of NP AF in a range of 50 to 160 DMC-U per pancreas. Isolation, culture, and quality assessment were performed using standard techniques as previously described. All data are presented as mean ± standard error of the mean (SEM). Variability of pancreas weight was associated with a wide range of collagenase and NP activities, ranging from 12.7 to 46.6 PZ-U/g (26.0 ± 1.5 PZ-U/g) and 0.4 to 3.0 DMC-U/g (1.5 ± 0.1 DMC-U/g), respectively. Postpurification islet yield was 296,494 ± 33,620 islet equivalents (IEQ) equivalent to 3,274 ± 450 IEQ/g with a purity of 55.9% ± 3.2%. Quality assessment performed after 2 to 4 d of culture demonstrated a viability of 88.1% ± 1.5% and a stimulation index of 3.7 ± 0.7. Eighteen of the 34 preparations were transplanted into type 1 diabetic patients equivalent to a transplantation rate of 52.9%. Six preparations, which were infused into patients as first transplant, could be analyzed and increased the fasting C-peptide level from 0.11 ± 0.08 pretransplant to 1.23 ± 0.24 and 2.27 ± 0.31 ng/mL 3 and 6 mo posttransplant (P < 0.05), respectively. Insulin requirements were simultaneously reduced at the same time from 39.2 ± 3.8 IU/d before transplantation to 10.8 ± 4.1 and 4.0 ± 2.3 IU/d, after 3 and 6 mo posttransplant (P < 0.05), respectively. This study demonstrates the efficiency of AF SERVA Collagenase AF-1 and NP AF for clinical islet isolation and transplantation. The new plant-based production process makes these products a safe new option for the islet field.
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Affiliation(s)
- Daniel Brandhorst
- 1 Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom.,2 Oxford Centre for Diabetes, Endocrinology, and Metabolism (OCDEM), Churchill Hospital, Oxford, United Kingdom
| | - Géraldine Parnaud
- 3 Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospital, Geneva, Switzerland
| | - Andrew Friberg
- 4 Department of Immunology, Genetics and Pathology, University of Uppsala, Uppsala, Sweden
| | - Vanessa Lavallard
- 3 Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospital, Geneva, Switzerland
| | - Sandrine Demuylder-Mischler
- 3 Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospital, Geneva, Switzerland
| | - Stephen Hughes
- 1 Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom.,2 Oxford Centre for Diabetes, Endocrinology, and Metabolism (OCDEM), Churchill Hospital, Oxford, United Kingdom
| | | | | | - Olle Korsgren
- 4 Department of Immunology, Genetics and Pathology, University of Uppsala, Uppsala, Sweden
| | - Thierry Berney
- 3 Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospital, Geneva, Switzerland
| | - Paul R V Johnson
- 1 Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom.,2 Oxford Centre for Diabetes, Endocrinology, and Metabolism (OCDEM), Churchill Hospital, Oxford, United Kingdom
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Leighton PLA, Kanyo R, Neil GJ, Pollock NM, Allison WT. Prion gene paralogs are dispensable for early zebrafish development and have nonadditive roles in seizure susceptibility. J Biol Chem 2018; 293:12576-12592. [PMID: 29903907 DOI: 10.1074/jbc.ra117.001171] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 06/07/2018] [Indexed: 11/06/2022] Open
Abstract
Normally folded prion protein (PrPC) and its functions in healthy brains remain underappreciated compared with the intense study of its misfolded forms ("prions," PrPSc) during the pathobiology of prion diseases. This impedes the development of therapeutic strategies in Alzheimer's and prion diseases. Disrupting the zebrafish homologs of PrPC has provided novel insights; however, mutagenesis of the zebrafish paralog prp2 did not recapitulate previous dramatic developmental phenotypes, suggesting redundancy with the prp1 paralog. Here, we generated zebrafish prp1 loss-of-function mutant alleles and dual prp1-/-;prp2-/- mutants. Zebrafish prp1-/- and dual prp1-/-;prp2-/- mutants resemble mammalian Prnp knockouts insofar as they lack overt phenotypes, which surprisingly contrasts with reports of severe developmental phenotypes when either prp1 or prp2 is knocked down acutely. Previous studies suggest that PrPC participates in neural cell development/adhesion, including in zebrafish where loss of prp2 affects adhesion and deposition patterns of lateral line neuromasts. In contrast with the expectation that prp1's functions would be redundant to prp2, they appear to have opposing functions in lateral line neurodevelopment. Similarly, loss of prp1 blunted the seizure susceptibility phenotypes observed in prp2 mutants, contrasting the expected exacerbation of phenotypes if these prion gene paralogs were serving redundant roles. In summary, prion mutant fish lack the overt phenotypes previously predicted, and instead they have subtle phenotypes similar to mammals. No evidence was found for functional redundancy in the zebrafish prion gene paralogs, and the phenotypes observed when each gene is disrupted individually are consistent with ancient functions of prion proteins in neurodevelopment and modulation of neural activity.
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Affiliation(s)
- Patricia L A Leighton
- From the Department of Biological Sciences and the Centre for Prion and Protein Folding Diseases, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - Richard Kanyo
- From the Department of Biological Sciences and the Centre for Prion and Protein Folding Diseases, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - Gavin J Neil
- From the Department of Biological Sciences and the Centre for Prion and Protein Folding Diseases, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - Niall M Pollock
- From the Department of Biological Sciences and the Centre for Prion and Protein Folding Diseases, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - W Ted Allison
- From the Department of Biological Sciences and the Centre for Prion and Protein Folding Diseases, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
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Kanata E, Arsenakis M, Sklaviadis T. Caprine PrP variants harboring Asp-146, His-154 and Gln-211 alleles display reduced convertibility upon interaction with pathogenic murine prion protein in scrapie infected cells. Prion 2017; 10:391-408. [PMID: 27537339 DOI: 10.1080/19336896.2016.1199312] [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: 12/31/2022] Open
Abstract
Scrapie, the prion disease of sheep and goats, is a devastating malady of small ruminants. Due to its infectious nature, epidemic outbreaks may occur in flocks/herds consisting of highly susceptible animals. Field studies identified scrapie-protective caprine PrP variants, harboring specific single amino acid changes (Met-142, Arg-143, Asp-146, Ser-146, His-154, Gln-211 and Lys-222). Their effects are under further evaluation, and aim to determine the most protective allele. We assessed some of these variants (Asp-146, His-154, Gln-211 and Lys-222), after their exogenous expression as murine-caprine chimeras in a scrapie- infected murine cell line. We report that exogenously expressed PrPs undergo conformational conversion upon interaction with the endogenous pathological murine prion protein (PrPSC), which results in the detection of goat-specific and partially PK-resistant moieties. These moieties display a PK-resistance pattern distinct from the one detected in natural goat scrapie cases. Within this cellular model, distinct conformational conversion potentials were assigned to the tested variants. Molecules carrying the Asp-146, His-154 and Gln-211 alleles showed significantly lower conversion levels compared to wild type, confirming their protective effects against scrapie. Although we utilized a heterologous conversion system, this is to our knowledge, the first study of caprine PrP variants in a cellular context of scrapie, that confirms the protective effects of some of the studied alleles.
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Affiliation(s)
- Eirini Kanata
- a Department of Genetics , Development and Molecular Biology, School of Biology, Aristotle University of Thessaloniki , Thessaloniki , Greece.,b School of Pharmacy , Aristotle University of Thessaloniki , Thessaloniki , Greece
| | - Minas Arsenakis
- a Department of Genetics , Development and Molecular Biology, School of Biology, Aristotle University of Thessaloniki , Thessaloniki , Greece
| | - Theodoros Sklaviadis
- b School of Pharmacy , Aristotle University of Thessaloniki , Thessaloniki , Greece
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Allison WT, DuVal MG, Nguyen-Phuoc K, Leighton PLA. Reduced Abundance and Subverted Functions of Proteins in Prion-Like Diseases: Gained Functions Fascinate but Lost Functions Affect Aetiology. Int J Mol Sci 2017; 18:E2223. [PMID: 29064456 PMCID: PMC5666902 DOI: 10.3390/ijms18102223] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 10/18/2017] [Accepted: 10/20/2017] [Indexed: 12/12/2022] Open
Abstract
Prions have served as pathfinders that reveal many aspects of proteostasis in neurons. The recent realization that several prominent neurodegenerative diseases spread via a prion-like mechanism illuminates new possibilities for diagnostics and therapeutics. Thus, key proteins in Alzheimer Disease and Amyotrophic lateral sclerosis (ALS), including amyloid-β precursor protein, Tau and superoxide dismutase 1 (SOD1), spread to adjacent cells in their misfolded aggregated forms and exhibit template-directed misfolding to induce further misfolding, disruptions to proteostasis and toxicity. Here we invert this comparison to ask what these prion-like diseases can teach us about the broad prion disease class, especially regarding the loss of these key proteins' function(s) as they misfold and aggregate. We also consider whether functional amyloids might reveal a role for subverted protein function in neurodegenerative disease. Our synthesis identifies SOD1 as an exemplar of protein functions being lost during prion-like protein misfolding, because SOD1 is inherently unstable and loses function in its misfolded disease-associated form. This has under-appreciated parallels amongst the canonical prion diseases, wherein the normally folded prion protein, PrPC, is reduced in abundance in fatal familial insomnia patients and during the preclinical phase in animal models, apparently via proteostatic mechanisms. Thus while template-directed misfolding and infectious properties represent gain-of-function that fascinates proteostasis researchers and defines (is required for) the prion(-like) diseases, loss and subversion of the functions attributed to hallmark proteins in neurodegenerative disease needs to be integrated into design towards effective therapeutics. We propose experiments to uniquely test these ideas.
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Affiliation(s)
- W Ted Allison
- Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton, AB T6G 2M8, Canada.
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada.
- Department of Medical Genetics, University of Alberta, Edmonton, AB T6G 2M8, Canada.
| | - Michèle G DuVal
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada.
| | - Kim Nguyen-Phuoc
- Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton, AB T6G 2M8, Canada.
- Department of Medical Genetics, University of Alberta, Edmonton, AB T6G 2M8, Canada.
| | - Patricia L A Leighton
- Centre for Prions & Protein Folding Disease, University of Alberta, Edmonton, AB T6G 2M8, Canada.
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9, Canada.
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