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Ma X, Li M, Wang X, Qi G, Wei L, Zhang D. Sialylation in the gut: From mucosal protection to disease pathogenesis. Carbohydr Polym 2024; 343:122471. [PMID: 39174097 DOI: 10.1016/j.carbpol.2024.122471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Revised: 06/19/2024] [Accepted: 07/07/2024] [Indexed: 08/24/2024]
Abstract
Sialylation, a crucial post-translational modification of glycoconjugates, entails the attachment of sialic acid (SA) to the terminal glycans of glycoproteins and glycolipids through a tightly regulated enzymatic process involving various enzymes. This review offers a comprehensive exploration of sialylation within the gut, encompassing its involvement in mucosal protection and its impact on disease progression. The sialylation of mucins and epithelial glycoproteins contributes to the integrity of the intestinal mucosal barrier. Furthermore, sialylation regulates immune responses in the gut, shaping interactions among immune cells, as well as their activation and tolerance. Additionally, the gut microbiota and gut-brain axis communication are involved in the role of sialylation in intestinal health. Altered sialylation patterns have been implicated in various intestinal diseases, including inflammatory bowel disease (IBD), colorectal cancer (CRC), and other intestinal disorders. Emerging research underscores sialylation as a promising avenue for diagnostic, prognostic, and therapeutic interventions in intestinal diseases. Potential strategies such as sialic acid supplementation, inhibition of sialidases, immunotherapy targeting sialylated antigens, and modulation of sialyltransferases have been utilized in the treatment of intestinal diseases. Future research directions will focus on elucidating the molecular mechanisms underlying sialylation alterations, identifying sialylation-based biomarkers, and developing targeted interventions for precision medicine approaches.
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Affiliation(s)
- Xueni Ma
- Key Laboratory of Digestive Diseases, Lanzhou University Second Hospital, Lanzhou, China; The Second Clinical Medical College, Lanzhou University, Lanzhou, China
| | - Muyang Li
- Key Laboratory of Digestive Diseases, Lanzhou University Second Hospital, Lanzhou, China; The Second Clinical Medical College, Lanzhou University, Lanzhou, China
| | - Xiaochun Wang
- Department of Gastroenterology, Gansu Provincial Hospital, Lanzhou, China
| | - Guoqing Qi
- Department of Gastroenterology, Lanzhou University Second Hospital, Lanzhou, China
| | - Lina Wei
- Department of Gastroenterology, Lanzhou University Second Hospital, Lanzhou, China
| | - Dekui Zhang
- Key Laboratory of Digestive Diseases, Lanzhou University Second Hospital, Lanzhou, China; Department of Gastroenterology, Lanzhou University Second Hospital, Lanzhou, China.
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2
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Makarava N, Kushwaha R, Baskakov IV. Reactive astrocytes in prion diseases: Friend or foe? PLoS Pathog 2024; 20:e1012286. [PMID: 38900746 PMCID: PMC11189187 DOI: 10.1371/journal.ppat.1012286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/22/2024] Open
Affiliation(s)
- Natallia Makarava
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Rajesh Kushwaha
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Ilia V. Baskakov
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
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3
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Giri RK. Molecular signatures in prion disease: altered death receptor pathways in a mouse model. J Transl Med 2024; 22:503. [PMID: 38802941 PMCID: PMC11129387 DOI: 10.1186/s12967-024-05121-x] [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: 12/02/2023] [Accepted: 03/20/2024] [Indexed: 05/29/2024] Open
Abstract
BACKGROUND Prion diseases are transmissible and fatal neurodegenerative diseases characterized by accumulation of misfolded prion protein isoform (PrPSc), astrocytosis, microgliosis, spongiosis, and neurodegeneration. Elevated levels of cell membrane associated PrPSc protein and inflammatory cytokines hint towards the activation of death receptor (DR) pathway/s in prion diseases. Activation of DRs regulate, either cell survival or apoptosis, autophagy and necroptosis based on the adaptors they interact. Very little is known about the DR pathways activation in prion disease. DR3 and DR5 that are expressed in normal mouse brain were never studied in prion disease, so also their ligands and any DR adaptors. This research gap is notable and investigated in the present study. METHODS C57BL/6J mice were infected with Rocky Mountain Laboratory scrapie mouse prion strain. The progression of prion disease was examined by observing morphological and behavioural abnormalities. The levels of PrP isoforms and GFAP were measured as the marker of PrPSc accumulation and astrocytosis respectively using antibody-based techniques that detect proteins on blot and brain section. The levels of DRs, their glycosylation and ectodomain shedding, and associated factors warrant their examination at protein level, hence western blot analysis was employed in this study. RESULTS Prion-infected mice developed motor deficits and neuropathology like PrPSc accumulation and astrocytosis similar to other prion diseases. Results from this research show higher expression of all DR ligands, TNFR1, Fas and p75NTR but decreased levels DR3 and DR5. The levels of DR adaptor proteins like TRADD and TRAF2 (primarily regulate pro-survival pathways) are reduced. FADD, which primarily regulate cell death, its level remains unchanged. RIPK1, which regulate pro-survival, apoptosis and necroptosis, its expression and proteolysis (inhibits necroptosis but activates apoptosis) are increased. CONCLUSIONS The findings from the present study provide evidence towards the involvement of DR3, DR5, DR6, TL1A, TRAIL, TRADD, TRAF2, FADD and RIPK1 for the first time in prion diseases. The knowledge obtained from this research discuss the possible impacts of these 16 differentially expressed DR factors on our understanding towards the multifaceted neuropathology of prion diseases and towards future explorations into potential targeted therapeutic interventions for prion disease specific neuropathology.
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Affiliation(s)
- Ranjit Kumar Giri
- Molecular and Cellular Neuroscience Division, National Brain Research Centre, Manesar, Gurgaon, Haryana, 122052, India.
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Hay A, Popichak K, Moreno J, Zabel M. The Role of Glial Cells in Neurobiology and Prion Neuropathology. Cells 2024; 13:832. [PMID: 38786054 PMCID: PMC11119027 DOI: 10.3390/cells13100832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 05/07/2024] [Accepted: 05/09/2024] [Indexed: 05/25/2024] Open
Abstract
Prion diseases are rare and neurodegenerative diseases that are characterized by the misfolding and infectious spread of the prion protein in the brain, causing progressive and irreversible neuronal loss and associated clinical and behavioral manifestations in humans and animals, ultimately leading to death. The brain has a complex network of neurons and glial cells whose crosstalk is critical for function and homeostasis. Although it is established that prion infection of neurons is necessary for clinical disease to occur, debate remains in the field as to the role played by glial cells, namely astrocytes and microglia, and whether these cells are beneficial to the host or further accelerate disease. Here, we review the current literature assessing the complex morphologies of astrocytes and microglia, and the crosstalk between these two cell types, in the prion-infected brain.
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Affiliation(s)
- Arielle Hay
- Division of Intramural Research, Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA
| | - Katriana Popichak
- Prion Research Center, Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA; (K.P.); (J.M.); (M.Z.)
| | - Julie Moreno
- Prion Research Center, Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA; (K.P.); (J.M.); (M.Z.)
- Department of Environmental and Radiological Health Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Mark Zabel
- Prion Research Center, Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA; (K.P.); (J.M.); (M.Z.)
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5
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Bocharova O, Makarava N, Pandit NP, Molesworth K, Baskakov IV. Multiple steps of prion strain adaptation to a new host. Front Neurosci 2024; 18:1329010. [PMID: 38362022 PMCID: PMC10867973 DOI: 10.3389/fnins.2024.1329010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 01/12/2024] [Indexed: 02/17/2024] Open
Abstract
The transmission of prions across species is a critical aspect of their dissemination among mammalian hosts, including humans. This process often necessitates strain adaptation. In this study, we sought to investigate the mechanisms underlying prion adaptation while mitigating biases associated with the history of cross-species transmission of natural prion strains. To achieve this, we utilized the synthetic hamster prion strain S05. Propagation of S05 using mouse PrPC in Protein Misfolding Cyclic Amplification did not immediately overcome the species barrier. This finding underscores the involvement of factors beyond disparities in primary protein structures. Subsequently, we performed five serial passages to stabilize the incubation time to disease in mice. The levels of PrPSc increased with each passage, reaching a maximum at the third passage, and declining thereafter. This suggests that only the initial stage of adaptation is primarily driven by an acceleration in PrPSc replication. During the protracted adaptation to a new host, we observed significant alterations in the glycoform ratio and sialylation status of PrPSc N-glycans. These changes support the notion that qualitative modifications in PrPSc contribute to a more rapid disease progression. Furthermore, consistent with the decline in sialylation, a cue for "eat me" signaling, the newly adapted strain exhibited preferential colocalization with microglia. In contrast to PrPSc dynamics, the intensity of microglia activation continued to increase after the third passage in the new host. In summary, our study elucidates that the adaptation of a prion strain to a new host is a multi-step process driven by several factors.
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Affiliation(s)
- Olga Bocharova
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Natallia Makarava
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Narayan P. Pandit
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Kara Molesworth
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Ilia V. Baskakov
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
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6
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Bocharova O, Makarava N, Pandit NP, Molesworth K, Baskakov IV. Multiple steps of prion strain adaptation to a new host. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.24.563743. [PMID: 37961127 PMCID: PMC10634783 DOI: 10.1101/2023.10.24.563743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The transmission of prions across species is a critical aspect of their dissemination among mammalian hosts, including humans. This process often necessitates strain adaptation. In this study, we sought to investigate the mechanisms underlying prion adaptation while mitigating biases associated with the history of cross-species transmission of natural prion strains. To achieve this, we utilized the synthetic hamster prion strain S05. Propagation of S05 using mouse PrPC in Protein Misfolding Cyclic Amplification did not immediately overcome the species barrier. This finding underscores the involvement of factors beyond disparities in primary protein structures. Subsequently, we performed five serial passages to stabilize the incubation time to disease in mice. The levels of PrPSc increased with each passage, reaching a maximum at the third passage, and declining thereafter. This suggests that only the initial stage of adaptation is primarily driven by an acceleration in PrPSc replication. During the protracted adaptation to a new host, we observed significant alterations in the glycoform ratio and sialylation status of PrPSc N-glycans. These changes support the notion that qualitative modifications in PrPSc contribute to a more rapid disease progression. Furthermore, consistent with the decline in sialylation, a cue for "eat me" signaling, the newly adapted strain exhibited preferential colocalization with microglia. In contrast to PrPSc dynamics, the intensity of microglia activation continued to increase after the third passage in the new host. In summary, our study elucidates that the adaptation of a prion strain to a new host is a multi-step process driven by several factors.
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Affiliation(s)
- Olga Bocharova
- Center for Biomedical Engineering and Technology, Baltimore, Maryland, USA
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Natallia Makarava
- Center for Biomedical Engineering and Technology, Baltimore, Maryland, USA
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Narayan P. Pandit
- Center for Biomedical Engineering and Technology, Baltimore, Maryland, USA
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Kara Molesworth
- Center for Biomedical Engineering and Technology, Baltimore, Maryland, USA
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Ilia V. Baskakov
- Center for Biomedical Engineering and Technology, Baltimore, Maryland, USA
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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Makarava N, Baskakov IV. Role of sialylation of N-linked glycans in prion pathogenesis. Cell Tissue Res 2023; 392:201-214. [PMID: 35088180 PMCID: PMC9329487 DOI: 10.1007/s00441-022-03584-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 01/12/2022] [Indexed: 01/10/2023]
Abstract
Mammalian prion or PrPSc is a proteinaceous infectious agent that consists of a misfolded, self-replicating state of the prion protein or PrPC. PrPC and PrPSc are posttranslationally modified with N-linked glycans, which are sialylated at the terminal positions. More than 30 years have passed since the first characterization of the composition and structural diversity of N-linked glycans associated with the prion protein, yet the role of carbohydrate groups that constitute N-glycans and, in particular, their terminal sialic acid residues in prion disease pathogenesis remains poorly understood. A number of recent studies shed a light on the role of sialylation in the biology of prion diseases. This review article discusses several mechanisms by which terminal sialylation dictates the spread of PrPSc across brain regions and the outcomes of prion infection in an organism. In particular, relationships between the sialylation status of PrPSc and important strain-specific features including lymphotropism, neurotropism, and neuroinflammation are discussed. Moreover, emerging evidence pointing out the roles of sialic acid residues in prion replication, cross-species transmission, strain competition, and strain adaptation are reviewed. A hypothesis according to which selective, strain-specified recruitment of PrPC sialoglycoforms dictates unique strain-specific disease phenotypes is examined. Finally, the current article proposes that prion strains evolve as a result of a delicate balance between recruiting highly sialylated glycoforms to avoid an "eat-me" response by glia and limiting heavily sialylated glycoforms for enabling rapid prion replication.
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Affiliation(s)
- Natallia Makarava
- Center for Biomedical Engineering and Technology and Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Ilia V Baskakov
- Center for Biomedical Engineering and Technology and Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
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8
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Neuroinflammation microenvironment sharpens seizure circuit. Neurobiol Dis 2023; 178:106027. [PMID: 36736598 DOI: 10.1016/j.nbd.2023.106027] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/25/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023] Open
Abstract
A large set of inflammatory molecules and their receptors are induced in epileptogenic foci of patients with pharmacoresistant epilepsies of structural etiologies or with refractory status epilepticus. Studies in animal models mimicking these clinical conditions have shown that the activation of specific inflammatory signallings in forebrain neurons or glial cells may modify seizure thresholds, thus contributing to both ictogenesis and epileptogenesis. The search for mechanisms underlying these effects has highlighted that inflammatory mediators have CNS-specific neuromodulatory functions, in addition to their canonical activation of immune responses for pathogen recognition and clearance. This review reports the neuromodulatory effects of inflammatory mediators and how they contribute to alter the inhibitory/excitatory balance in neural networks that underlie seizures. In particular, we describe key findings related to the ictogenic role of prototypical inflammatory cytokines (IL-1β and TNF) and danger signals (HMGB1), their modulatory effects of neuronal excitability, and the mechanisms underlying these effects. It will be discussed how harnessing these neuromodulatory properties of immune mediators may lead to novel therapies to control drug-resistant seizures.
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9
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Hay AJD, Murphy TJ, Popichak KA, Zabel MD, Moreno JA. Adipose-derived mesenchymal stromal cells decrease prion-induced glial inflammation in vitro. Sci Rep 2022; 12:22567. [PMID: 36581683 PMCID: PMC9800558 DOI: 10.1038/s41598-022-26628-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 12/16/2022] [Indexed: 12/30/2022] Open
Abstract
Prion diseases are characterized by the cellular prion protein, PrPC, misfolding and aggregating into the infectious prion protein, PrPSc, which leads to neurodegeneration and death. An early sign of disease is inflammation in the brain and the shift of resting glial cells to reactive astrocytes and activated microglia. Few therapeutics target this stage of disease. Mesenchymal stromal cells produce anti-inflammatory molecules when exposed to inflammatory signals and damaged tissue. Here, we show that adipose-derived mesenchymal stromal cells (AdMSCs) migrate toward prion-infected brain homogenate and produce the anti-inflammatory molecules transforming growth factor β (TGFβ) and tumor necrosis factor-stimulated gene 6 (TSG-6). In an in vitro model of prion exposure of both primary mixed glia and BV2 microglial cell line, co-culturing with AdMSCs led to a significant decrease in inflammatory cytokine mRNA and markers of reactive astrocytes and activated microglia. This protection against in vitro prion-associated inflammatory responses is independent of PrPSc replication. These data support a role for AdMSCs as a beneficial therapeutic for decreasing the early onset of glial inflammation and reprogramming glial cells to a protective phenotype.
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Affiliation(s)
- Arielle J. D. Hay
- grid.47894.360000 0004 1936 8083Prion Research Center, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523 USA ,grid.47894.360000 0004 1936 8083Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523 USA
| | - Tanner J. Murphy
- grid.47894.360000 0004 1936 8083Prion Research Center, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523 USA ,grid.47894.360000 0004 1936 8083Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523 USA ,grid.47894.360000 0004 1936 8083Department of Environmental and Radiological Health Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523 USA
| | - Katriana A. Popichak
- grid.47894.360000 0004 1936 8083Prion Research Center, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523 USA ,grid.47894.360000 0004 1936 8083Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523 USA ,grid.47894.360000 0004 1936 8083Present Address: Center for Healthy Aging, Colorado State University, Fort Collins, CO 80523 USA
| | - Mark D. Zabel
- grid.47894.360000 0004 1936 8083Prion Research Center, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523 USA ,grid.47894.360000 0004 1936 8083Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523 USA ,grid.47894.360000 0004 1936 8083Present Address: Center for Healthy Aging, Colorado State University, Fort Collins, CO 80523 USA
| | - Julie A. Moreno
- grid.47894.360000 0004 1936 8083Prion Research Center, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523 USA ,grid.47894.360000 0004 1936 8083Department of Environmental and Radiological Health Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523 USA ,grid.47894.360000 0004 1936 8083Present Address: Center for Healthy Aging, Colorado State University, Fort Collins, CO 80523 USA
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10
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Makarava N, Katorcha E, Chang JCY, Lau JTY, Baskakov IV. Deficiency in ST6GAL1, one of the two α2,6-sialyltransferases, has only a minor effect on the pathogenesis of prion disease. Front Mol Biosci 2022; 9:1058602. [PMID: 36452458 PMCID: PMC9702343 DOI: 10.3389/fmolb.2022.1058602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 10/31/2022] [Indexed: 10/22/2023] Open
Abstract
Prion diseases are a group of fatal neurodegenerative diseases caused by misfolding of the normal cellular form of the prion protein or PrPC, into a disease-associated self-replicating state or PrPSc. PrPC and PrPSc are posttranslationally modified with N-linked glycans, in which the terminal positions occupied by sialic acids residues are attached to galactose predominantly via α2-6 linkages. The sialylation status of PrPSc is an important determinant of prion disease pathogenesis, as it dictates the rate of prion replication and controls the fate of prions in an organism. The current study tests whether a knockout of ST6Gal1, one of the two mammalian sialyltransferases that catalyze the sialylation of glycans via α2-6 linkages, reduces the sialylation status of PrPSc and alters prion disease pathogenesis. We found that a global knockout of ST6Gal1 in mice significantly reduces the α2-6 sialylation of the brain parenchyma, as determined by staining with Sambucus Nigra agglutinin. However, the sialylation of PrPSc remained stable and the incubation time to disease increased only modestly in ST6Gal1 knockout mice (ST6Gal1-KO). A lack of significant changes in the PrPSc sialylation status and prion pathogenesis is attributed to the redundancy in sialylation and, in particular, the plausible involvement of a second member of the sialyltransferase family that sialylate via α2-6 linkages, ST6Gal2.
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Affiliation(s)
- Natallia Makarava
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Elizaveta Katorcha
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Jennifer Chen-Yu Chang
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Joseph T. Y. Lau
- Department of Molecular and Cellular Biology, Roswell Park Comprehensive Cancer Center, Buffalo, NY, United States
| | - Ilia V. Baskakov
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
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11
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Wang Y, Hartmann K, Thies E, Mohammadi B, Altmeppen H, Sepulveda-Falla D, Glatzel M, Krasemann S. Loss of Homeostatic Microglia Signature in Prion Diseases. Cells 2022; 11:cells11192948. [PMID: 36230910 PMCID: PMC9563810 DOI: 10.3390/cells11192948] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 09/12/2022] [Accepted: 09/15/2022] [Indexed: 11/16/2022] Open
Abstract
Prion diseases are neurodegenerative diseases that affect humans and animals. They are always fatal and, to date, no treatment exists. The hallmark of prion disease pathophysiology is the misfolding of an endogenous protein, the cellular prion protein (PrPC), into its disease-associated isoform PrPSc. Besides the aggregation and deposition of misfolded PrPSc, prion diseases are characterized by spongiform lesions and the activation of astrocytes and microglia. Microglia are the innate immune cells of the brain. Activated microglia and astrocytes represent a common pathological feature in neurodegenerative disorders. The role of activated microglia has already been studied in prion disease mouse models; however, it is still not fully clear how they contribute to disease progression. Moreover, the role of microglia in human prion diseases has not been thoroughly investigated thus far, and specific molecular pathways are still undetermined. Here, we review the current knowledge on the different roles of microglia in prion pathophysiology. We discuss microglia markers that are also dysregulated in other neurodegenerative diseases including microglia homeostasis markers. Data on murine and human brain tissues show that microglia are highly dysregulated in prion diseases. We highlight here that the loss of homeostatic markers may especially stand out.
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12
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Quercetin binding accelerates prion fibrillation into proteinase sensitive and loosely structured amyloids. Biomed Pharmacother 2022; 151:113177. [PMID: 35676783 DOI: 10.1016/j.biopha.2022.113177] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/18/2022] [Accepted: 05/22/2022] [Indexed: 11/23/2022] Open
Abstract
Amyloidoses are caused by the deposition of amyloid fibrils ascribed to protein misfolding. In this study, we examined the antiamyloidogenic and antioxidative activities of quercetin, a plant flavonol from the flavonoid group of polyphenols, on mouse prion protein (moPrP) with biophysical approaches. As the results show, quercetin binds to the C-terminal region of moPrP, and quercetin binding does not affect the structure of moPrP. However, quercetin binding accelerates moPrP fibrillation and changes the structure of moPrP fibrils. Unlike typical prion fibrils, quercetin-bound fibrils are sensitive to proteinase K and are loosely structured. Moreover, due to high antioxidant activity of flavonoid, quercetin-bound fibrils lack imbalance of free radicals and, therefore, they are nontoxic towards neuroblastoma cells. The quercetin shows its uniqueness from typical antiamyloidogenic drugs which either suppress the development of amyloid or eliminate formed amyloids. Quercetin binding converts moPrP into protease-sensitive and non-cytotoxic fibrils. This work provides a powerful resolution in the advancement of antiamyloidogenic treatment.
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García-Martínez M, Cortez LM, Otero A, Betancor M, Serrano-Pérez B, Bolea R, Badiola JJ, Garza MC. Distinctive Toll-like Receptors Gene Expression and Glial Response in Different Brain Regions of Natural Scrapie. Int J Mol Sci 2022; 23:ijms23073579. [PMID: 35408945 PMCID: PMC8998348 DOI: 10.3390/ijms23073579] [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: 03/09/2022] [Revised: 03/22/2022] [Accepted: 03/23/2022] [Indexed: 11/16/2022] Open
Abstract
Prion diseases are chronic and fatal neurodegenerative diseases characterized by the accumulation of disease-specific prion protein (PrPSc), spongiform changes, neuronal loss, and gliosis. Growing evidence shows that the neuroinflammatory response is a key component of prion diseases and contributes to neurodegeneration. Toll-like receptors (TLRs) have been proposed as important mediators of innate immune responses triggered in the central nervous system in other human neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis. However, little is known about the role of TLRs in prion diseases, and their involvement in the neuropathology of natural scrapie has not been studied. We assessed the gene expression of ovine TLRs in four anatomically distinct brain regions in natural scrapie-infected sheep and evaluated the possible correlations between gene expression and the pathological hallmarks of prion disease. We observed significant changes in TLR expression in scrapie-infected sheep that correlate with the degree of spongiosis, PrPSc deposition, and gliosis in each of the regions studied. Remarkably, TLR4 was the only gene upregulated in all regions, regardless of the severity of neuropathology. In the hippocampus, we observed milder neuropathology associated with a distinct TLR gene expression profile and the presence of a peculiar microglial morphology, called rod microglia, described here for the first time in the brain of scrapie-infected sheep. The concurrence of these features suggests partial neuroprotection of the hippocampus. Finally, a comparison of the findings in naturallyinfected sheep versus an ovinized mouse model (tg338 mice) revealed distinct patterns of TLRgene expression.
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Affiliation(s)
- Mirta García-Martínez
- Centro de Encefalopatías y Enfermedades Transmisibles Emergentes, IA2, IIS Aragón, Universidad de Zaragoza, 50013 Zaragoza, Spain; (M.G.-M.); (M.B.); (R.B.); (J.J.B.)
| | - Leonardo M. Cortez
- Department of Medicine and Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB T6G 2G3, Canada
- Correspondence: (L.M.C.); (A.O.)
| | - Alicia Otero
- Centro de Encefalopatías y Enfermedades Transmisibles Emergentes, IA2, IIS Aragón, Universidad de Zaragoza, 50013 Zaragoza, Spain; (M.G.-M.); (M.B.); (R.B.); (J.J.B.)
- Correspondence: (L.M.C.); (A.O.)
| | - Marina Betancor
- Centro de Encefalopatías y Enfermedades Transmisibles Emergentes, IA2, IIS Aragón, Universidad de Zaragoza, 50013 Zaragoza, Spain; (M.G.-M.); (M.B.); (R.B.); (J.J.B.)
| | - Beatriz Serrano-Pérez
- Agrotecnio-CERCA Center, Department of Animal Science, University of Lleida, 25198 Lleida, Spain;
| | - Rosa Bolea
- Centro de Encefalopatías y Enfermedades Transmisibles Emergentes, IA2, IIS Aragón, Universidad de Zaragoza, 50013 Zaragoza, Spain; (M.G.-M.); (M.B.); (R.B.); (J.J.B.)
| | - Juan J. Badiola
- Centro de Encefalopatías y Enfermedades Transmisibles Emergentes, IA2, IIS Aragón, Universidad de Zaragoza, 50013 Zaragoza, Spain; (M.G.-M.); (M.B.); (R.B.); (J.J.B.)
| | - María Carmen Garza
- Departamento de Anatomía e Histología Humanas, IIS Aragón, Universidad de Zaragoza, 50009 Zaragoza, Spain;
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Brahadeeswaran S, Sivagurunathan N, Calivarathan L. Inflammasome Signaling in the Aging Brain and Age-Related Neurodegenerative Diseases. Mol Neurobiol 2022; 59:2288-2304. [PMID: 35066762 DOI: 10.1007/s12035-021-02683-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/06/2021] [Indexed: 12/28/2022]
Abstract
Inflammasomes are intracellular protein complexes, members of the innate immune system, and their activation and regulation play an essential role in maintaining homeostatic conditions against exogenous and endogenous stimuli. Inflammasomes occur as cytosolic proteins and assemble into a complex during the recognition of pathogen-associated or danger-associated molecular patterns by pattern-recognition receptors in host cells. The formation of the inflammasome complex elicits signaling molecules of proinflammatory cytokines such as interleukin-1β and interleukin 18 via activation of caspase-1 in the canonical inflammasome pathway whereas caspase-11 in the case of a mouse and caspase-4 and caspase-5 in the case of humans in the non-canonical inflammasome pathway, resulting in pyroptotic or inflammatory cell death which ultimately leads to neuroinflammation and neurodegenerative diseases. Inflammasome activation, particularly in microglial cells and macrophages, has been linked to aging as well as age-related neurodegenerative diseases. The accumulation of abnormal/ misfolded proteins acts as a ligand for inflammasome activation in neurodegenerative diseases. Although recent studies have revealed the inflammasomes' functionality in both in vitro and in vivo models, many inflammasome signaling cascade activations during biological aging, neuroinflammation, and neurodegeneration are still ambiguous. In this review, we comprehensively unveil the cellular and molecular mechanisms of inflammasome activation during neuronal aging and age-related neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, Huntington's disease, multiple sclerosis, prion disease, and amyotrophic lateral sclerosis.
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Affiliation(s)
- Subhashini Brahadeeswaran
- Molecular Pharmacology and Toxicology Laboratory, Department of Life Sciences, School of Life Sciences, Central University of Tamil Nadu, Neelakudi Campus, Thiruvarur, Tamil Nadu, 610005, India
| | - Narmadhaa Sivagurunathan
- Molecular Pharmacology and Toxicology Laboratory, Department of Life Sciences, School of Life Sciences, Central University of Tamil Nadu, Neelakudi Campus, Thiruvarur, Tamil Nadu, 610005, India
| | - Latchoumycandane Calivarathan
- Molecular Pharmacology and Toxicology Laboratory, Department of Life Sciences, School of Life Sciences, Central University of Tamil Nadu, Neelakudi Campus, Thiruvarur, Tamil Nadu, 610005, India.
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15
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Chaudhary S, Ashok A, Wise AS, Rana NA, McDonald D, Kritikos AE, Kong Q, Singh N. Upregulation of brain hepcidin in prion diseases. Prion 2021; 15:126-137. [PMID: 34224321 PMCID: PMC8259718 DOI: 10.1080/19336896.2021.1946377] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 06/04/2021] [Accepted: 06/17/2021] [Indexed: 12/14/2022] Open
Abstract
Accumulation of redox-active iron in human sporadic Creutzfeldt-Jakob disease (sCJD) brain tissue and scrapie-infected mouse brains has been demonstrated previously. Here, we explored whether upregulation of local hepcidin secreted within the brain is the underlying cause of iron accumulation and associated toxicity. Using scrapie-infected mouse brains, we demonstrate transcriptional upregulation of hepcidin relative to controls. As a result, ferroportin (Fpn), the downstream effector of hepcidin and the only known iron export protein was downregulated, and ferritin, an iron storage protein was upregulated, suggesting increased intracellular iron. A similar transcriptional and translational upregulation of hepcidin, and decreased expression of Fpn and an increase in ferritin expression was observed in sCJD brain tissue. Further evaluation in human neuroblastoma cells (M17) exposed to synthetic mini-hepcidin showed downregulation of Fpn, upregulation of ferritin, and an increase in reactive oxygen species (ROS), resulting in cytotoxicity in a dose-dependent manner. Similar effects were noted in primary neurons isolated from mouse brain. As in M17 cells, primary neurons accumulated ferritin and ROS, and showed toxicity at five times lower concentration of mini-hepcidin. These observations suggest that upregulation of brain hepcidin plays a significant role in iron accumulation and associated neurotoxicity in human and animal prion disorders.
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Affiliation(s)
- Suman Chaudhary
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Ajay Ashok
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Aaron S. Wise
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Neil A. Rana
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Dallas McDonald
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Alexander E. Kritikos
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Qingzhong Kong
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Neena Singh
- Department of Pathology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
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Adhikari UK, Sakiz E, Zhou X, Habiba U, Kumar S, Mikhael M, Senesi M, Guang Li C, Guillemin GJ, Ooi L, David MA, Collins S, Karl T, Tayebi M. Cross-Linking Cellular Prion Protein Induces Neuronal Type 2-Like Hypersensitivity. Front Immunol 2021; 12:639008. [PMID: 34394070 PMCID: PMC8361482 DOI: 10.3389/fimmu.2021.639008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 07/13/2021] [Indexed: 01/13/2023] Open
Abstract
Background Previous reports identified proteins associated with ‘apoptosis’ following cross-linking PrPC with motif-specific anti-PrP antibodies in vivo and in vitro. The molecular mechanisms underlying this IgG-mediated neurotoxicity and the role of the activated proteins in the apoptotic pathways leading to neuronal death has not been properly defined. Previous reports implicated a number of proteins, including apolipoprotein E, cytoplasmic phospholipase A2, prostaglandin and calpain with anti-PrP antibody-mediated ‘apoptosis’, however, these proteins are also known to play an important role in allergy. In this study, we investigated whether cross-linking PrPC with anti-PrP antibodies stimulates a neuronal allergenic response. Methods Initially, we predicted the allergenicity of the epitope sequences associated with ‘neurotoxic’ anti-PrP antibodies using allergenicity prediction servers. We then investigated whether anti-PrP antibody treatment of mouse primary neurons (MPN), neuroblastoma cells (N2a) and microglia (N11) cell lines lead to a neuronal allergenic response. Results In-Silico studies showed that both tail- and globular-epitopes were allergenic. Specifically, binding regions that contain epitopes for previously reported ‘neurotoxic’ antibodies such as ICSM18 (146-159), ICSM35 (91-110), POM 1 (138-147) and POM 3 (95-100) lead to activation of allergenic related proteins. Following direct application of anti-PrPC antibodies on N2a cells, we identified 4 neuronal allergenic-related proteins when compared with untreated cells. Furthermore, we identified 8 neuronal allergenic-related proteins following treatment of N11 cells with anti-PrPC antibodies prior to co-culture with N2a cells when compared with untreated cells. Antibody treatment of MPN or MPN co-cultured with antibody-treated N11 led to identifying 10 and 7 allergenic-related proteins when compared with untreated cells. However, comparison with 3F4 antibody treatment revealed 5 and 4 allergenic-related proteins respectively. Of importance, we showed that the allergenic effects triggered by the anti-PrP antibodies were more potent when antibody-treated microglia were co-cultured with the neuroblastoma cell line. Finally, co-culture of N2a or MPN with N11-treated with anti-PrP antibodies resulted in significant accumulation of NO and IL6 but not TNF-α in the cell culture media supernatant. Conclusions This study showed for the first time that anti-PrP antibody binding to PrPC triggers a neuronal hypersensitivity response and highlights the important role of microglia in triggering an IgG-mediated neuronal hypersensitivity response. Moreover, this study provides an important impetus for including allergenic assessment of therapeutic antibodies for neurodegenerative disorders to derive safe and targeted biotherapeutics.
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Affiliation(s)
| | - Elif Sakiz
- School of Medicine, Western Sydney University, Campbelltown, NSW, Australia
| | - Xian Zhou
- National Institute of Complementary Medicine (NICM) Health Research Institute, Western Sydney University, Campbelltown, NSW, Australia
| | - Umma Habiba
- School of Medicine, Western Sydney University, Campbelltown, NSW, Australia
| | - Sachin Kumar
- School of Medicine, Western Sydney University, Campbelltown, NSW, Australia
| | - Meena Mikhael
- School of Medicine, Western Sydney University, Campbelltown, NSW, Australia
| | - Matteo Senesi
- Australian National Creutzfeldt-Jakob Disease Registry, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia.,Department of Medicine, Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia
| | - Chun Guang Li
- National Institute of Complementary Medicine (NICM) Health Research Institute, Western Sydney University, Campbelltown, NSW, Australia
| | - Gilles J Guillemin
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Wollongong, NSW, Australia
| | - Lezanne Ooi
- School of Chemistry and Molecular Bioscience, Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia.,School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
| | | | - Steven Collins
- Australian National Creutzfeldt-Jakob Disease Registry, The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, VIC, Australia.,Department of Medicine, Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, Australia
| | - Tim Karl
- School of Medicine, Western Sydney University, Campbelltown, NSW, Australia.,Neuroscience Research Australia (NeuRA), Sydney, NSW, Australia.,School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Mourad Tayebi
- School of Medicine, Western Sydney University, Campbelltown, NSW, Australia
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17
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Sinha A, Kushwaha R, Molesworth K, Mychko O, Makarava N, Baskakov IV. Phagocytic Activities of Reactive Microglia and Astrocytes Associated with Prion Diseases Are Dysregulated in Opposite Directions. Cells 2021; 10:1728. [PMID: 34359897 PMCID: PMC8304827 DOI: 10.3390/cells10071728] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/02/2021] [Accepted: 07/04/2021] [Indexed: 01/11/2023] Open
Abstract
Phagocytosis is one of the most important physiological functions of the glia directed at maintaining a healthy, homeostatic environment in the brain. Under a homeostatic environment, the phagocytic activities of astrocytes and microglia are tightly coordinated in time and space. In neurodegenerative diseases, both microglia and astrocytes contribute to neuroinflammation and disease pathogenesis, however, whether their phagocytic activities are up- or downregulated in reactive states is not known. To address this question, this current study isolated microglia and astrocytes from C57BL/6J mice infected with prions and tested their phagocytic activities in live-cell imaging assays that used synaptosomes and myelin debris as substrates. The phagocytic uptake by the reactive microglia was found to be significantly upregulated, whereas that of the reactive astrocytes was strongly downregulated. The up- and downregulation of phagocytosis by the two cell types were observed irrespective of whether disease-associated synaptosomes, normal synaptosomes, or myelin debris were used in the assays, indicating that dysregulations are dictated by cell reactive states, not substrates. Analysis of gene expression confirmed dysregulation of phagocytic functions in both cell types. Immunostaining of animal brains infected with prions revealed that at the terminal stage of disease, neuronal cell bodies were subject to engulfment by reactive microglia. This study suggests that imbalance in the phagocytic activities of the reactive microglia and astrocytes, which are dysregulated in opposite directions, is likely to lead to excessive microglia-mediated neuronal death on the one hand, and the inability of astrocytes to clear cell debris on the other hand, contributing to the neurotoxic effects of glia as a whole.
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Affiliation(s)
- Anshuman Sinha
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.S.); (R.K.); (K.M.); (O.M.); (N.M.)
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Rajesh Kushwaha
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.S.); (R.K.); (K.M.); (O.M.); (N.M.)
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Kara Molesworth
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.S.); (R.K.); (K.M.); (O.M.); (N.M.)
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Olga Mychko
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.S.); (R.K.); (K.M.); (O.M.); (N.M.)
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Natallia Makarava
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.S.); (R.K.); (K.M.); (O.M.); (N.M.)
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Ilia V. Baskakov
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (A.S.); (R.K.); (K.M.); (O.M.); (N.M.)
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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Abstract
Transformation of astrocytes into reactive states is considered one of the major pathological hallmarks of prion and other neurodegenerative diseases. Recent years witnessed a growing appreciation of the view that reactive astrocytes are intimately involved in chronic neurodegeneration; however, little is known about their role in disease pathogenesis. The current article reviews the progress of the last few years and critically discusses controversial questions of whether reactive astrocytes associated with prion diseases are neurotoxic or neuroprotective and whether bidirectional A1–A2 model is applicable for describing polarization of astrocytes. Moreover, other important topics, including reversibility of a transition to a reactive state, along with the role of microglia and other stimuli in triggering astrocyte activation are reviewed. Defining the role of reactive astrocytes in pathogenesis of neurodegenerative diseases will open unrealized opportunities for developing new therapeutic approaches against prion and other neurodegenerative diseases.
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Affiliation(s)
- Ilia V Baskakov
- Department of Anatomy and Neurobiology, And Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA
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19
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Garcés M, Guijarro IM, Ritchie DL, Badiola JJ, Monzón M. Novel Morphological Glial Alterations in the Spectrum of Prion Disease Types: A Focus on Common Findings. Pathogens 2021; 10:pathogens10050596. [PMID: 34068251 PMCID: PMC8153175 DOI: 10.3390/pathogens10050596] [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: 04/13/2021] [Revised: 04/26/2021] [Accepted: 05/11/2021] [Indexed: 01/12/2023] Open
Abstract
Human prion diseases are a group of rare fatal neurodegenerative diseases with sporadic, genetic, and acquired forms. They are neuropathologically characterized by pathological prion protein accumulation, neuronal death, and vacuolation. Classical immunological response has long been known not to play a major in prion diseases; however, gliosis is known to be a common feature although variable in extent and poorly described. In this investigation, astrogliosis and activated microglia in two brain regions were assessed and compared with non-neurologically affected patients in a representative sample across the spectrum of Creutzfeldt–Jakob disease (CJD) forms and subtypes in order to analyze the influence of prion strain on pathological processes. In this report, we choose to focus on features common to all CJD types rather than the diversity among them. Novel pathological changes in both glial cell types were found to be shared by all CJD types. Microglial activation correlated to astrogliosis. Spongiosis, but not pathological prion protein deposition, correlated to both astrogliosis and microgliosis. At the ultrastructural level, astrocytic glial filaments correlated with pathological changes associated with prion disease. These observations confirm that neuroglia play a prominent role in the neurodegenerative process of prion diseases, regardless of the causative prion type.
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Affiliation(s)
- Moisés Garcés
- Research Centre for Encephalopathies and Transmissible Emerging Diseases, Institute for Health Research Aragón (IIS), University of Zaragoza, 50013 Zaragoza, Spain; (M.G.); (I.M.G.); (J.J.B.)
| | - Isabel M. Guijarro
- Research Centre for Encephalopathies and Transmissible Emerging Diseases, Institute for Health Research Aragón (IIS), University of Zaragoza, 50013 Zaragoza, Spain; (M.G.); (I.M.G.); (J.J.B.)
| | - Diane L. Ritchie
- National CJD Research & Surveillance Unit, Centre for Clinical Brain Sciences, The University of Edinburgh, Edinburgh EH4 2XU, UK;
| | - Juan J. Badiola
- Research Centre for Encephalopathies and Transmissible Emerging Diseases, Institute for Health Research Aragón (IIS), University of Zaragoza, 50013 Zaragoza, Spain; (M.G.); (I.M.G.); (J.J.B.)
| | - Marta Monzón
- Research Centre for Encephalopathies and Transmissible Emerging Diseases, Institute for Health Research Aragón (IIS), University of Zaragoza, 50013 Zaragoza, Spain; (M.G.); (I.M.G.); (J.J.B.)
- Correspondence: ; Tel.: +34-976-762944
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20
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The degree of astrocyte activation is predictive of the incubation time to prion disease. Acta Neuropathol Commun 2021; 9:87. [PMID: 33980286 PMCID: PMC8114720 DOI: 10.1186/s40478-021-01192-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 05/03/2021] [Indexed: 12/18/2022] Open
Abstract
In neurodegenerative diseases including Alzheimer’s, Parkinson’s and prion diseases, astrocytes acquire disease-associated reactive phenotypes. With growing appreciation of their role in chronic neurodegeneration, the questions whether astrocytes lose their ability to perform homeostatic functions in the reactive states and whether the reactive phenotypes are neurotoxic or neuroprotective remain unsettled. The current work examined region-specific changes in expression of genes, which report on astrocyte physiological functions and their reactive states, in C57Black/6J mice challenged with four prion strains via two inoculation routes. Unexpectedly, strong reverse correlation between the incubation time to the diseases and the degree of astrocyte activation along with disturbance in functional pathways was observed. The animal groups with the most severe astrocyte response and degree of activation showed the most rapid disease progression. The degree of activation tightly intertwined with the global transformation of the homeostatic state, characterized by disturbances in multiple gene sets responsible for normal physiological functions producing a neurotoxic, reactive phenotype as a net result. The neurotoxic reactive phenotype exhibited a universal gene signature regardless of the prion strain. The current work suggests that the degree of astrocyte activation along with the disturbance in their physiological pathways contribute to the faster progression of disease and perhaps even drive prion pathogenesis.
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21
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Kushwaha R, Sinha A, Makarava N, Molesworth K, Baskakov IV. Non-cell autonomous astrocyte-mediated neuronal toxicity in prion diseases. Acta Neuropathol Commun 2021; 9:22. [PMID: 33546775 PMCID: PMC7866439 DOI: 10.1186/s40478-021-01123-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 01/14/2021] [Indexed: 02/08/2023] Open
Abstract
Under normal conditions, astrocytes perform a number of important physiological functions centered around neuronal support and synapse maintenance. In neurodegenerative diseases including Alzheimer’s, Parkinson’s and prion diseases, astrocytes acquire reactive phenotypes, which are sustained throughout the disease progression. It is not known whether in the reactive states associated with prion diseases, astrocytes lose their ability to perform physiological functions and whether the reactive states are neurotoxic or, on the contrary, neuroprotective. The current work addresses these questions by testing the effects of reactive astrocytes isolated from prion-infected C57BL/6J mice on primary neuronal cultures. We found that astrocytes isolated at the clinical stage of the disease exhibited reactive, pro-inflammatory phenotype, which also showed downregulation of genes involved in neurogenic and synaptogenic functions. In astrocyte-neuron co-cultures, astrocytes from prion-infected animals impaired neuronal growth, dendritic spine development and synapse maturation. Toward examining the role of factors secreted by reactive astrocytes, astrocyte-conditioned media was found to have detrimental effects on neuronal viability and synaptogenic functions via impairing synapse integrity, and by reducing spine size and density. Reactive microglia isolated from prion-infected animals were found to induce phenotypic changes in primary astrocytes reminiscent to those observed in prion-infected mice. In particular, astrocytes cultured with reactive microglia-conditioned media displayed hypertrophic morphology and a downregulation of genes involved in neurogenic and synaptogenic functions. In summary, the current study provided experimental support toward the non-cell autonomous mechanisms behind neurotoxicity in prion diseases and demonstrated that the astrocyte reactive phenotype associated with prion diseases is synaptotoxic.
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22
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From Posttranslational Modifications to Disease Phenotype: A Substrate Selection Hypothesis in Neurodegenerative Diseases. Int J Mol Sci 2021; 22:ijms22020901. [PMID: 33477465 PMCID: PMC7830165 DOI: 10.3390/ijms22020901] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/12/2021] [Accepted: 01/15/2021] [Indexed: 11/16/2022] Open
Abstract
A number of neurodegenerative diseases including prion diseases, tauopathies and synucleinopathies exhibit multiple clinical phenotypes. A diversity of clinical phenotypes has been attributed to the ability of amyloidogenic proteins associated with a particular disease to acquire multiple, conformationally distinct, self-replicating states referred to as strains. Structural diversity of strains formed by tau, α-synuclein or prion proteins has been well documented. However, the question how different strains formed by the same protein elicit different clinical phenotypes remains poorly understood. The current article reviews emerging evidence suggesting that posttranslational modifications are important players in defining strain-specific structures and disease phenotypes. This article put forward a new hypothesis referred to as substrate selection hypothesis, according to which individual strains selectively recruit protein isoforms with a subset of posttranslational modifications that fit into strain-specific structures. Moreover, it is proposed that as a result of selective recruitment, strain-specific patterns of posttranslational modifications are formed, giving rise to unique disease phenotypes. Future studies should define whether cell-, region- and age-specific differences in metabolism of posttranslational modifications play a causative role in dictating strain identity and structural diversity of strains of sporadic origin.
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23
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Short and sweet: How glycans impact prion conversion, cofactor interactions, and cross-species transmission. PLoS Pathog 2021; 17:e1009123. [PMID: 33444414 PMCID: PMC7808606 DOI: 10.1371/journal.ppat.1009123] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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Timmerman R, Burm SM, Bajramovic JJ. Tissue-specific features of microglial innate immune responses. Neurochem Int 2020; 142:104924. [PMID: 33248205 DOI: 10.1016/j.neuint.2020.104924] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 11/21/2020] [Accepted: 11/22/2020] [Indexed: 02/07/2023]
Abstract
As tissue-resident macrophages of the brain, microglia are increasingly considered as cellular targets for therapeutical intervention. Innate immune responses in particular have been implicated in central nervous system (CNS) infections, neuro-oncology, neuroinflammatory and neurodegenerative diseases. We here review the impact of 'nature and nurture' on microglial innate immune responses and summarize documented tissue-specific adaptations. Overall, such adaptations are associated with regulatory processes rather than with overt differences in the expressed repertoire of activating receptors of different tissue-resident macrophages. Microglial responses are characterized by slower kinetics, by a more persistent nature and by a differential usage of downstream enzymes and accessory receptors. We further consider factors like aging, previous exposure to inflammatory stimuli, and differences in the microenvironment that can modulate innate immune responses. The long-life span of microglia in the metabolically active CNS renders them susceptible to the phenomenon of 'inflammaging', and major challenges lie in the unraveling of the factors that underlie age-related alterations in microglial behavior.
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Affiliation(s)
- R Timmerman
- Alternatives Unit, Biomedical Primate Research Centre, Rijswijk, the Netherlands
| | - S M Burm
- Genmab, Utrecht, the Netherlands
| | - J J Bajramovic
- Alternatives Unit, Biomedical Primate Research Centre, Rijswijk, the Netherlands.
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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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Mabbott NA, Bradford BM, Pal R, Young R, Donaldson DS. The Effects of Immune System Modulation on Prion Disease Susceptibility and Pathogenesis. Int J Mol Sci 2020; 21:E7299. [PMID: 33023255 PMCID: PMC7582561 DOI: 10.3390/ijms21197299] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 09/25/2020] [Accepted: 09/29/2020] [Indexed: 12/17/2022] Open
Abstract
Prion diseases are a unique group of infectious chronic neurodegenerative disorders to which there are no cures. Although prion infections do not stimulate adaptive immune responses in infected individuals, the actions of certain immune cell populations can have a significant impact on disease pathogenesis. After infection, the targeting of peripherally-acquired prions to specific immune cells in the secondary lymphoid organs (SLO), such as the lymph nodes and spleen, is essential for the efficient transmission of disease to the brain. Once the prions reach the brain, interactions with other immune cell populations can provide either host protection or accelerate the neurodegeneration. In this review, we provide a detailed account of how factors such as inflammation, ageing and pathogen co-infection can affect prion disease pathogenesis and susceptibility. For example, we discuss how changes to the abundance, function and activation status of specific immune cell populations can affect the transmission of prion diseases by peripheral routes. We also describe how the effects of systemic inflammation on certain glial cell subsets in the brains of infected individuals can accelerate the neurodegeneration. A detailed understanding of the factors that affect prion disease transmission and pathogenesis is essential for the development of novel intervention strategies.
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Affiliation(s)
- Neil A. Mabbott
- The Roslin Institute & Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, UK; (B.M.B.); (R.P.); (R.Y.); (D.S.D.)
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Baskakov IV. Role of sialylation in prion disease pathogenesis and prion structure. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 175:31-52. [PMID: 32958238 DOI: 10.1016/bs.pmbts.2020.07.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Mammalian prion or PrPSc is a proteinaceous infectious agent that consists of a misfolded, self-replicating state of a sialoglycoprotein called the prion protein or PrPC. Sialylation of the prion protein, a terminal modification of N-linked glycans, was discovered more than 30 years ago, yet the role of sialylation in prion pathogenesis is not well understood. This chapter summarizes current knowledge on the role of sialylation of the prion protein in prion diseases. First, we discuss recent data suggesting that sialylation of PrPSc N-linked glycans determines the fate of prion infection in an organism and control prion lymphotropism. Second, emerging evidence pointing out at the role N-glycans in neuroinflammation are discussed. Thirds, this chapter reviews a mechanism postulating that sialylated N-linked glycans are important players in defining strain-specific structures. A new hypothesis according to which individual strain-specific PrPSc structures govern selection of PrPC sialoglycoforms is discussed. Finally, this chapter explain how N-glycan sialylation control the prion replication and strain interference. In summary, comprehensive review of our knowledge on N-linked glycans and their sialylation provided in this chapter helps to answer important questions of prion biology that have been puzzling for years.
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Affiliation(s)
- Ilia V Baskakov
- Department of Anatomy and Neurobiology, and Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States.
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Makarava N, Chang JCY, Molesworth K, Baskakov IV. Posttranslational modifications define course of prion strain adaptation and disease phenotype. J Clin Invest 2020; 130:4382-4395. [PMID: 32484800 PMCID: PMC7410085 DOI: 10.1172/jci138677] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 05/13/2020] [Indexed: 12/13/2022] Open
Abstract
Posttranslational modifications are a common feature of proteins associated with neurodegenerative diseases including prion protein (PrPC), tau, and α-synuclein. Alternative self-propagating protein states or strains give rise to different disease phenotypes and display strain-specific subsets of posttranslational modifications. The relationships between strain-specific structure, posttranslational modifications, and disease phenotype are poorly understood. We previously reported that among hundreds of PrPC sialoglycoforms expressed by a cell, individual prion strains recruited PrPC molecules selectively, according to the sialylation status of their N-linked glycans. Here we report that transmission of a prion strain to a new host is accompanied by a dramatic shift in the selectivity of recruitment of PrPC sialoglycoforms, giving rise to a self-propagating scrapie isoform (PrPSc) with a unique sialoglycoform signature and disease phenotype. The newly emerged strain has the shortest incubation time to disease and is characterized by colocalization of PrPSc with microglia and a very profound proinflammatory response, features that are linked to a unique sialoglycoform composition of PrPSc. The current work provides experimental support for the hypothesis that strain-specific patterns of PrPSc sialoglycoforms formed as a result of selective recruitment dictate strain-specific disease phenotypes. This work suggests a causative relationship between a strain-specific structure, posttranslational modifications, and disease phenotype.
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Affiliation(s)
- Natallia Makarava
- Center for Biomedical Engineering and Technology and
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Jennifer Chen-Yu Chang
- Center for Biomedical Engineering and Technology and
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Kara Molesworth
- Center for Biomedical Engineering and Technology and
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Ilia V. Baskakov
- Center for Biomedical Engineering and Technology and
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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29
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Callender JA, Sevillano AM, Soldau K, Kurt TD, Schumann T, Pizzo DP, Altmeppen H, Glatzel M, Esko JD, Sigurdson CJ. Prion protein post-translational modifications modulate heparan sulfate binding and limit aggregate size in prion disease. Neurobiol Dis 2020; 142:104955. [PMID: 32454127 DOI: 10.1016/j.nbd.2020.104955] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 05/09/2020] [Accepted: 05/21/2020] [Indexed: 01/05/2023] Open
Abstract
Many aggregation-prone proteins linked to neurodegenerative disease are post-translationally modified during their biogenesis. In vivo pathogenesis studies have suggested that the presence of post-translational modifications can shift the aggregate assembly pathway and profoundly alter the disease phenotype. In prion disease, the N-linked glycans and GPI-anchor on the prion protein (PrP) impair fibril assembly. However, the relevance of the two glycans to aggregate structure and disease progression remains unclear. Here we show that prion-infected knockin mice expressing an additional PrP glycan (tri-glycosylated PrP) develop new plaque-like deposits on neuronal cell membranes, along the subarachnoid space, and periventricularly, suggestive of high prion mobility and transit through the interstitial fluid. These plaque-like deposits were largely non-congophilic and composed of full length, uncleaved PrP, indicating retention of the glycophosphatidylinositol (GPI) anchor. Prion aggregates sedimented in low density fractions following ultracentrifugation, consistent with oligomers, and bound low levels of heparan sulfate (HS) similar to other predominantly GPI-anchored prions. Collectively, these results suggest that highly glycosylated PrP primarily converts as a GPI-anchored glycoform, with low involvement of HS co-factors, limiting PrP assembly mainly to oligomers. Since PrPC is highly glycosylated, these findings may explain the high frequency of diffuse, synaptic, and plaque-like deposits in the brain as well as the rapid conversion commonly observed in human and animal prion disease.
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Affiliation(s)
| | | | - Katrin Soldau
- Departments of Pathology, UC San Diego, La Jolla, CA 92093, USA
| | - Timothy D Kurt
- Departments of Pathology, UC San Diego, La Jolla, CA 92093, USA
| | - Taylor Schumann
- Departments of Pathology, UC San Diego, La Jolla, CA 92093, USA
| | - Donald P Pizzo
- Departments of Pathology, UC San Diego, La Jolla, CA 92093, USA
| | - Hermann Altmeppen
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, 20251, Germany
| | - Markus Glatzel
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, 20251, Germany
| | - Jeffrey D Esko
- Department of Cellular and Molecular Medicine, UC San Diego, La Jolla, CA 92093, USA
| | - Christina J Sigurdson
- Department of Pathology, Microbiology, and Immunology, UC Davis, Davis, CA 95616, USA; Departments of Medicine, UC San Diego, La Jolla, CA 92093, USA.
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Makarava N, Chang JCY, Baskakov IV. Region-Specific Sialylation Pattern of Prion Strains Provides Novel Insight into Prion Neurotropism. Int J Mol Sci 2020; 21:ijms21030828. [PMID: 32012886 PMCID: PMC7037812 DOI: 10.3390/ijms21030828] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 01/10/2020] [Accepted: 01/23/2020] [Indexed: 12/14/2022] Open
Abstract
Mammalian prions are unconventional infectious agents that invade and replicate in an organism by recruiting a normal form of a prion protein (PrPC) and converting it into misfolded, disease-associated state referred to as PrPSc. PrPC is posttranslationally modified with two N-linked glycans. Prion strains replicate by selecting substrates from a large pool of PrPC sialoglycoforms expressed by a host. Brain regions have different vulnerability to prion infection, however, molecular mechanisms underlying selective vulnerability is not well understood. Toward addressing this question, the current study looked into a possibility that sialylation of PrPSc might be involved in defining selective vulnerability of brain regions. The current work found that in 22L -infected animals, PrPSc is indeed sialylated in a region dependent manner. PrPSc in hippocampus and cortex was more sialylated than PrPSc from thalamus and stem. Similar trends were also observed in brain materials from RML- and ME7-infected animals. The current study established that PrPSc sialylation status is indeed region-specific. Together with previous studies demonstrating that low sialylation status accelerates prion replication, this work suggests that high vulnerability of certain brain region to prion infection could be attributed to their low sialylation status.
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Affiliation(s)
- Natallia Makarava
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (N.M.); (J.C.-Y.C.)
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Jennifer Chen-Yu Chang
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (N.M.); (J.C.-Y.C.)
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Ilia V. Baskakov
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (N.M.); (J.C.-Y.C.)
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
- Correspondence:
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Region-specific glial homeostatic signature in prion diseases is replaced by a uniform neuroinflammation signature, common for brain regions and prion strains with different cell tropism. Neurobiol Dis 2020; 137:104783. [PMID: 32001329 DOI: 10.1016/j.nbd.2020.104783] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 01/21/2020] [Accepted: 01/25/2020] [Indexed: 02/08/2023] Open
Abstract
Chronic neuroinflammation is recognized as a major neuropathological hallmark in a broad spectrum of neurodegenerative diseases including Alzheimer's, Parkinson's, Frontal Temporal Dementia, Amyotrophic Lateral Sclerosis, and prion diseases. Both microglia and astrocytes exhibit region-specific homeostatic transcriptional identities, which under chronic neurodegeneration, transform into reactive phenotypes in a region- and disease-specific manner. Little is known about region-specific identity of glia in prion diseases. The current study was designed to determine whether the region-specific homeostatic signature of glia changes with the progression of prion diseases, and whether these changes occur in a region-dependent or universal manner. Also of interest was whether different prion strains give rise to different reactive phenotypes. To answer these questions, we analyzed gene expression in the thalamus, cortex, hypothalamus and hippocampus of mice infected with 22L and ME7 prion strains using a Nanostring Neuroinflammation panel at the subclinical, early clinical and advanced stages of the disease. We found that at the preclinical stage of the disease, the region-specific homeostatic identities were preserved. However, with the appearance of clinical signs, the region-specific signatures were partially lost and replaced with a neuroinflammation signature. While the same sets of genes were activated by both prion strains, the timing of neuroinflammation and the degree of activation in different brain regions was strain-specific. Changes in astrocyte function scored at the top of the activated pathways. Moreover, clustering analysis suggested that the astrocyte function pathway responded to prion infection prior to the Activated Microglia or Neuron and Neurotransmission pathways. The current work established neuroinflammation gene expression signature associated with prion diseases. Our results illustrate that with the disease progression, the region-specific homeostatic transcriptome signatures are replaced by the region-independent neuroinflammation signature, which is common for prion strains with different cell tropism. The prion-associated neuroinflammation signature identified in the current study overlapped only partially with the microglia degenerative phenotype and the disease-associated microglia phenotype reported for animal models of other neurodegenerative diseases.
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Modulation of Innate Immunity by Amyloidogenic Peptides. Trends Immunol 2019; 40:762-780. [PMID: 31320280 DOI: 10.1016/j.it.2019.06.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 06/11/2019] [Accepted: 06/12/2019] [Indexed: 12/11/2022]
Abstract
Amyloid formation contributes to the development of progressive metabolic and neurodegenerative diseases, while also serving functional roles in host defense. Emerging evidence suggests that as amyloidogenic peptides populate distinct aggregation states, they interact with different combinations of pattern recognition receptors (PRRs) to direct the phenotype and function of tissue-resident and infiltrating innate immune cells. We review recent evidence of innate immunomodulation by distinct forms of amyloidogenic peptides produced by mammals (humans, non-human primates), bacteria, and fungi, as well as the corresponding cell-surface and intracellular PRRs in these interactions, in human and mouse models. Our emerging understanding of peptide aggregate-innate immune cell interactions, and the factors regulating the balance between amyloid function and pathogenicity, might aid the development of anti-amyloid and immunomodulating therapies.
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Butnaru D, Chapman J. The impact of self-replicating proteins on inflammation, autoimmunity and neurodegeneration-An untraveled path. Autoimmun Rev 2019; 18:231-240. [PMID: 30639644 DOI: 10.1016/j.autrev.2018.09.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 09/12/2018] [Indexed: 02/08/2023]
Abstract
The central nervous system (CNS) in neurodegenerative diseases is a battlefield in which microglia fight a highly atypical battle. During the inflammatory process microglia themselves become dysfunctional and even with all the available immune arsenal including cytokine or/and antibody production, the battle is eventually lost. A closer look into the picture will reveal the fact that this is mainly due to the atypical characteristics of the infectious agent. The supramolecular assemblies of misfolded proteins carry unique features not encountered in any of the common pathogens. Through misfolding, proteins undergo conformational changes which make them become immunogenic, neurotoxic and highly infective. The immunogenicity appears to be triggered by the exposure of previously hidden hydrophobic portions in proteins which act as damage-associated molecular patters (DAMPs) for the immune system. The neurotoxicity and infectivity are promoted by the small oligomeric forms of misfolded proteins/peptides. Oligomers adopt conformations such as tubular-like, beta-barrel-like, etc., that penetrate cell membranes through their hydrophobic surfaces, thus destabilizing ionic homeostasis. At the same time, oligomers act as a seed for protein misfolding through a prion/prion-like mechanism. Here, we propose the hypothesis that oligomers have catalytic surfaces and exercise their capacity to infect native proteins through specific characteristics such as hydrophobic, electrostatic and π-π stacking interactions as well as the specific surface area (SSA), surface curvature and surface chemistry of their nanoscale supramolecular assemblies. All these are the key elements for prion/prion-like mechanism of self-replication and disease spreading within the CNS. Thus, understanding the mechanism of prion's templating activity may help us in the prevention and development of novel therapeutic strategies for neurodegenerative diseases.
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Affiliation(s)
- Dana Butnaru
- The Zabludowicz Center for Autoimmune Diseases, Sheba Medical Center, Tel Hashomer, Israel.
| | - Joab Chapman
- Sheba Medical Center, Israel; Robert and Martha Harden Chair in Mental and Neurological Diseases, Sackler Faculty of Medicine, Tel Aviv University, Israel
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Baskakov IV, Katorcha E, Makarava N. Prion Strain-Specific Structure and Pathology: A View from the Perspective of Glycobiology. Viruses 2018; 10:v10120723. [PMID: 30567302 PMCID: PMC6315442 DOI: 10.3390/v10120723] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 12/13/2018] [Accepted: 12/15/2018] [Indexed: 01/15/2023] Open
Abstract
Prion diseases display multiple disease phenotypes characterized by diverse clinical symptoms, different brain regions affected by the disease, distinct cell tropism and diverse PrPSc deposition patterns. The diversity of disease phenotypes within the same host is attributed to the ability of PrPC to acquire multiple, alternative, conformationally distinct, self-replicating PrPSc states referred to as prion strains or subtypes. Structural diversity of PrPSc strains has been well documented, yet the question of how different PrPSc structures elicit multiple disease phenotypes remains poorly understood. The current article reviews emerging evidence suggesting that carbohydrates in the form of sialylated N-linked glycans, which are a constitutive part of PrPSc, are important players in defining strain-specific structures and disease phenotypes. This article introduces a new hypothesis, according to which individual strain-specific PrPSc structures govern selection of PrPC sialoglycoforms that form strain-specific patterns of carbohydrate epitopes on PrPSc surface and contribute to defining the disease phenotype and outcomes.
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Affiliation(s)
- Ilia V Baskakov
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MA 21201, USA.
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MA 21201, USA.
| | - Elizaveta Katorcha
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MA 21201, USA.
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MA 21201, USA.
| | - Natallia Makarava
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MA 21201, USA.
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MA 21201, USA.
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