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Grimaldi I, Leser FS, Janeiro JM, da Rosa BG, Campanelli AC, Romão L, Lima FRS. The multiple functions of PrP C in physiological, cancer, and neurodegenerative contexts. J Mol Med (Berl) 2022; 100:1405-1425. [PMID: 36056255 DOI: 10.1007/s00109-022-02245-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 08/05/2022] [Accepted: 08/09/2022] [Indexed: 11/29/2022]
Abstract
Cellular prion protein (PrPC) is a highly conserved glycoprotein, present both anchored in the cell membrane and soluble in the extracellular medium. It has a diversity of ligands and is variably expressed in numerous tissues and cell subtypes, most notably in the central nervous system (CNS). Its importance has been brought to light over the years both under physiological conditions, such as embryogenesis and immune system homeostasis, and in pathologies, such as cancer and neurodegenerative diseases. During development, PrPC plays an important role in CNS, participating in axonal growth and guidance and differentiation of glial cells, but also in other organs such as the heart, lung, and digestive system. In diseases, PrPC has been related to several types of tumors, modulating cancer stem cells, enhancing malignant properties, and inducing drug resistance. Also, in non-neoplastic diseases, such as Alzheimer's and Parkinson's diseases, PrPC seems to alter the dynamics of neurotoxic aggregate formation and, consequently, the progression of the disease. In this review, we explore in detail the multiple functions of this protein, which proved to be relevant for understanding the dynamics of organism homeostasis, as well as a promising target in the treatment of both neoplastic and degenerative diseases.
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Affiliation(s)
- Izabella Grimaldi
- Glial Cell Biology Laboratory, Biomedical Sciences Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Felipe Saceanu Leser
- Glial Cell Biology Laboratory, Biomedical Sciences Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - José Marcos Janeiro
- Glial Cell Biology Laboratory, Biomedical Sciences Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Bárbara Gomes da Rosa
- Glial Cell Biology Laboratory, Biomedical Sciences Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Ana Clara Campanelli
- Glial Cell Biology Laboratory, Biomedical Sciences Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Luciana Romão
- Cell Morphogenesis Laboratory, Biomedical Sciences Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Flavia Regina Souza Lima
- Glial Cell Biology Laboratory, Biomedical Sciences Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
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Microglia in Prion Diseases: Angels or Demons? Int J Mol Sci 2020; 21:ijms21207765. [PMID: 33092220 PMCID: PMC7589037 DOI: 10.3390/ijms21207765] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/16/2020] [Accepted: 10/16/2020] [Indexed: 02/08/2023] Open
Abstract
Prion diseases are rare transmissible neurodegenerative disorders caused by the accumulation of a misfolded isoform (PrPSc) of the cellular prion protein (PrPC) in the central nervous system (CNS). Neuropathological hallmarks of prion diseases are neuronal loss, astrogliosis, and enhanced microglial proliferation and activation. As immune cells of the CNS, microglia participate both in the maintenance of the normal brain physiology and in driving the neuroinflammatory response to acute or chronic (e.g., neurodegenerative disorders) insults. Microglia involvement in prion diseases, however, is far from being clearly understood. During this review, we summarize and discuss controversial findings, both in patient and animal models, suggesting a neuroprotective role of microglia in prion disease pathogenesis and progression, or—conversely—a microglia-mediated exacerbation of neurotoxicity in later stages of disease. We also will consider the active participation of PrPC in microglial functions, by discussing previous reports, but also by presenting unpublished results that support a role for PrPC in cytokine secretion by activated primary microglia.
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Reiten MR, Bakkebø MK, Brun-Hansen H, Lewandowska-Sabat AM, Olsaker I, Tranulis MA, Espenes A, Boysen P. Hematological shift in goat kids naturally devoid of prion protein. Front Cell Dev Biol 2015. [PMID: 26217662 PMCID: PMC4495340 DOI: 10.3389/fcell.2015.00044] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The physiological role of the cellular prion protein (PrPC) is incompletely understood. The expression of PrPC in hematopoietic stem cells and immune cells suggests a role in the development of these cells, and in PrPC knockout animals altered immune cell proliferation and phagocytic function have been observed. Recently, a spontaneous nonsense mutation at codon 32 in the PRNP gene in goats of the Norwegian Dairy breed was discovered, rendering homozygous animals devoid of PrPC. Here we report hematological and immunological analyses of homozygous goat kids lacking PrPC (PRNPTer/Ter) compared to heterozygous (PRNP+/Ter) and normal (PRNP+/+) kids. Levels of cell surface PrPC and PRNP mRNA in peripheral blood mononuclear cells (PBMCs) correlated well and were very low in PRNPTer/Ter, intermediate in PRNP+/Ter and high in PRNP+/+ kids. The PRNPTer/Ter animals had a shift in blood cell composition with an elevated number of red blood cells (RBCs) and a tendency toward a smaller mean RBC volume (P = 0.08) and an increased number of neutrophils (P = 0.068), all values within the reference ranges. Morphological investigations of blood smears and bone marrow imprints did not reveal irregularities. Studies of relative composition of PBMCs, phagocytic ability of monocytes and T-cell proliferation revealed no significant differences between the genotypes. Our data suggest that PrPC has a role in bone marrow physiology and warrant further studies of PrPC in erythroid and immune cell progenitors as well as differentiated effector cells also under stressful conditions. Altogether, this genetically unmanipulated PrPC-free animal model represents a unique opportunity to unveil the enigmatic physiology and function of PrPC.
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Affiliation(s)
- Malin R Reiten
- Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences Oslo, Norway
| | - Maren K Bakkebø
- Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences Oslo, Norway
| | - Hege Brun-Hansen
- Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences Oslo, Norway
| | - Anna M Lewandowska-Sabat
- Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences Oslo, Norway
| | - Ingrid Olsaker
- Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences Oslo, Norway
| | - Michael A Tranulis
- Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences Oslo, Norway
| | - Arild Espenes
- Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences Oslo, Norway
| | - Preben Boysen
- Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences Oslo, Norway
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Sakudo A, Onodera T. Prion protein (PrP) gene-knockout cell lines: insight into functions of the PrP. Front Cell Dev Biol 2015; 2:75. [PMID: 25642423 PMCID: PMC4295555 DOI: 10.3389/fcell.2014.00075] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 12/22/2014] [Indexed: 11/13/2022] Open
Abstract
Elucidation of prion protein (PrP) functions is crucial to fully understand prion diseases. A major approach to studying PrP functions is the use of PrP gene-knockout (Prnp (-/-)) mice. So far, six types of Prnp (-/-) mice have been generated, demonstrating the promiscuous functions of PrP. Recently, other PrP family members, such as Doppel and Shadoo, have been found. However, information obtained from comparative studies of structural and functional analyses of these PrP family proteins do not fully reveal PrP functions. Recently, varieties of Prnp (-/-) cell lines established from Prnp (-/-) mice have contributed to the analysis of PrP functions. In this mini-review, we focus on Prnp (-/-) cell lines and summarize currently available Prnp (-/-) cell lines and their characterizations. In addition, we introduce the recent advances in the methodology of cell line generation with knockout or knockdown of the PrP gene. We also discuss how these cell lines have provided valuable insights into PrP functions and show future perspectives.
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Affiliation(s)
- Akikazu Sakudo
- Laboratory of Biometabolic Chemistry, Faculty of Medicine, School of Health Sciences, University of the Ryukyus Nishihara, Japan
| | - Takashi Onodera
- Research Center for Food Safety, School of Agricultural and Life Sciences, University of Tokyo Tokyo, Japan
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Wang M, Zhao D, Yang Y, Liu J, Wang J, Yin X, Yang L, Zhou X. The cellular prion protein negatively regulates phagocytosis and cytokine expression in murine bone marrow-derived macrophages. PLoS One 2014; 9:e102785. [PMID: 25058617 PMCID: PMC4109954 DOI: 10.1371/journal.pone.0102785] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 06/23/2014] [Indexed: 11/19/2022] Open
Abstract
The cellular prion protein (PrPC) is a glycosylphosphatidylinositol (GPI)-anchored glycoprotein on the cell surface. Previous studies have demonstrated contradictory roles for PrPC in connection with the phagocytic ability of macrophages. In the present work, we investigated the function of PrPC in phagocytosis and cytokine expression in bone marrow-derived macrophages infected with Escherichia coli. E. coli infection induced an increase in the PRNP mRNA level. Knockout of PrPC promoted bacterial uptake; upregulated Rab5, Rab7, and Eea1 mRNA expression; and increased the recruitment of lysosomal-associated membrane protein-2 to phagosomes, suggesting enhanced microbicidal activity. Remarkably, knockout of PrPC suppressed the proliferation of internalized bacteria and increased the expression of cytokines such as interleukin-1β. Collectively, our data reveal an important role of PrPC as a negative regulator for phagocytosis, phagosome maturation, cytokine expression, and macrophage microbicidal activity.
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Affiliation(s)
- Min Wang
- State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Deming Zhao
- State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Yang Yang
- State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Jin Liu
- State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Jin Wang
- State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Xiaomin Yin
- State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Lifeng Yang
- State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Xiangmei Zhou
- State Key Laboratories for Agrobiotechnology, Key Lab of Animal Epidemiology and Zoonosis, Ministry of Agriculture, National Animal Transmissible Spongiform Encephalopathy Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China
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Nuvolone M, Kana V, Hutter G, Sakata D, Mortin-Toth SM, Russo G, Danska JS, Aguzzi A. SIRPα polymorphisms, but not the prion protein, control phagocytosis of apoptotic cells. ACTA ACUST UNITED AC 2013; 210:2539-52. [PMID: 24145514 PMCID: PMC3832919 DOI: 10.1084/jem.20131274] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Prnp(-/-) mice lack the prion protein PrP(C) and are resistant to prion infections, but variable phenotypes have been reported in Prnp(-/-) mice and the physiological function of PrP(C) remains poorly understood. Here we examined a cell-autonomous phenotype, inhibition of macrophage phagocytosis of apoptotic cells, previously reported in Prnp(-/-) mice. Using formal genetic, genomic, and immunological analyses, we found that the regulation of phagocytosis previously ascribed to PrP(C) is instead controlled by a linked locus encoding the signal regulatory protein α (Sirpa). These findings indicate that control of phagocytosis was previously misattributed to the prion protein and illustrate the requirement for stringent approaches to eliminate confounding effects of flanking genes in studies modeling human disease in gene-targeted mice. The plethora of seemingly unrelated functions attributed to PrP(C) suggests that additional phenotypes reported in Prnp(-/-) mice may actually relate to Sirpa or other genetic confounders.
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Affiliation(s)
- Mario Nuvolone
- Institute of Neuropathology, University Hospital of Zurich, CH-8091 Zurich, Switzerland
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Singh A, Haldar S, Horback K, Tom C, Zhou L, Meyerson H, Singh N. Prion protein regulates iron transport by functioning as a ferrireductase. J Alzheimers Dis 2013; 35:541-52. [PMID: 23478311 DOI: 10.3233/jad-130218] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Prion protein (PrPC) is implicated in the pathogenesis of prion disorders, but its normal function is unclear. We demonstrate that PrPC is a ferrireductase (FR), and its absence causes systemic iron deficiency in PrP knock-out mice (PrP-/-). When exposed to non-transferrin-bound (NTB) radioactive-iron (59FeCl3) by gastric-gavage, PrP-/- mice absorb significantly more 59Fe from the intestinal lumen relative to controls, indicating appropriate systemic response to the iron deficiency. Chronic exposure to excess dietary iron corrects this deficiency, but unlike wild-type (PrP+/+) controls that remain iron over-loaded, PrP-/- mice revert back to the iron deficient phenotype after 5 months of chase on normal diet. Bone marrow (BM) preparations of PrP-/- mice on normal diet show relatively less stainable iron, and this phenotype is only partially corrected by intraperitoneal administration of excess iron-dextran. Cultured PrP-/- BM-macrophages incorporate significantly less NTB-59Fe in the absence or presence of excess extracellular iron, indicating reduced uptake and/or storage of available iron in the absence of PrPC. When expressed in neuroblastoma cells, PrPC exhibits NAD(P)H-dependent cell-surface and intracellular FR activity that requires the copper-binding octa-peptide-repeat region and linkage to the plasma membrane for optimal function. Incorporation of NTB-59Fe by neuroblastoma cells correlates with FR activity of PrPC, implicating PrPC in cellular iron uptake and metabolism. These observations explain the correlation between PrPC expression and cellular iron levels, and the cause of iron imbalance in sporadic-Creutzfeldt-Jakob-disease brains where PrPC accumulates as insoluble aggregates.
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Affiliation(s)
- Ajay Singh
- Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA
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Jeon JW, Park BC, Jung JG, Jang YS, Shin EC, Park YW. The Soluble Form of the Cellular Prion Protein Enhances Phagocytic Activity and Cytokine Production by Human Monocytes Via Activation of ERK and NF-κB. Immune Netw 2013; 13:148-56. [PMID: 24009542 PMCID: PMC3759712 DOI: 10.4110/in.2013.13.4.148] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 07/19/2013] [Accepted: 07/22/2013] [Indexed: 02/01/2023] Open
Abstract
The PrP(C) is expressed in many types of immune cells including monocytes and macrophages, however, its function in immune regulation remains to be elucidated. In the present study, we examined a role for PrP(C) in regulation of monocyte function. Specifically, the effect of a soluble form of PrP(C) was studied in human monocytes. A recombinant fusion protein of soluble human PrP(C) fused with the Fc portion of human IgG1 (designated as soluble PrP(C)-Fc) bound to the cell surface of monocytes, induced differentiation to macrophage-like cells, and enhanced adherence and phagocytic activity. In addition, soluble PrP(C)-Fc stimulated monocytes to produce pro-inflammatory cytokines such as TNF-α, IL-1β, and IL-6. Both ERK and NF-κB signaling pathways were activated in soluble PrP(C)-treated monocytes, and inhibitors of either pathway abrogated monocyte adherence and cytokine production. Taken together, we conclude that soluble PrP(C)-Fc enhanced adherence, phagocytosis, and cytokine production of monocytes via activation of the ERK and NF-κB signaling pathways.
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Affiliation(s)
- Jae-Won Jeon
- Aging Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-806, Korea
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Bradford BM, Mabbott NA. Prion disease and the innate immune system. Viruses 2012; 4:3389-419. [PMID: 23342365 PMCID: PMC3528271 DOI: 10.3390/v4123389] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2012] [Revised: 11/14/2012] [Accepted: 11/22/2012] [Indexed: 02/06/2023] Open
Abstract
Prion diseases or transmissible spongiform encephalopathies are a unique category of infectious protein-misfolding neurodegenerative disorders. Hypothesized to be caused by misfolding of the cellular prion protein these disorders possess an infectious quality that thrives in immune-competent hosts. While much has been discovered about the routing and critical components involved in the peripheral pathogenesis of these agents there are still many aspects to be discovered. Research into this area has been extensive as it represents a major target for therapeutic intervention within this group of diseases. The main focus of pathological damage in these diseases occurs within the central nervous system. Cells of the innate immune system have been proven to be critical players in the initial pathogenesis of prion disease, and may have a role in the pathological progression of disease. Understanding how prions interact with the host innate immune system may provide us with natural pathways and mechanisms to combat these diseases prior to their neuroinvasive stage. We present here a review of the current knowledge regarding the role of the innate immune system in prion pathogenesis.
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Affiliation(s)
- Barry M Bradford
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Easter Bush Campus, Midlothian, EH25 9RG, UK.
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