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Latham AS, Rocha SM, McDermott CP, Reigan P, Slayden RA, Tjalkens RB. Neuroprotective efficacy of the glucocorticoid receptor modulator PT150 in the rotenone mouse model of Parkinson's disease. Neurotoxicology 2024; 103:320-334. [PMID: 38960072 DOI: 10.1016/j.neuro.2024.06.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 06/17/2024] [Accepted: 06/28/2024] [Indexed: 07/05/2024]
Abstract
Parkinson's disease (PD) is the most common neurodegenerative movement disorder worldwide. Current treatments for PD largely center around dopamine replacement therapies and fail to prevent the progression of pathology, underscoring the need for neuroprotective interventions. Approaches that target neuroinflammation, which occurs prior to dopaminergic neuron (DAn) loss in the substantia nigra (SN), represent a promising therapeutic strategy. The glucocorticoid receptor (GR) has been implicated in the neuropathology of PD and modulates numerous neuroinflammatory signaling pathways in the brain. Therefore, we investigated the neuroprotective effects of the novel GR modulator, PT150, in the rotenone mouse model of PD, postulating that inhibition of glial inflammation would protect DAn and reduce accumulation of neurotoxic misfolded ⍺-synuclein protein. C57Bl/6 mice were exposed to 2.5 mg/kg/day rotenone by intraperitoneal injection for 14 days. Upon completion of rotenone dosing, mice were orally treated at day 15 with 30 mg/kg/day or 100 mg/kg/day PT150 in the 14-day post-lesioning incubation period, during which the majority of DAn loss and α-synuclein (α-syn) accumulation occurs. Our results indicate that treatment with PT150 reduced both loss of DAn and microgliosis in the nigrostriatal pathway. Although morphologic features of astrogliosis were not attenuated, PT150 treatment promoted potentially neuroprotective activity in these cells, including increased phagocytosis of hyperphosphorylated α-syn. Ultimately, PT150 treatment reduced the loss of DAn cell bodies in the SN, but not the striatum, and prohibited intra-neuronal accumulation of α-syn. Together, these data indicate that PT150 effectively reduced SN pathology in the rotenone mouse model of PD.
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Affiliation(s)
- Amanda S Latham
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, United States
| | - Savannah M Rocha
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, United States
| | - Casey P McDermott
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, United States
| | - Philip Reigan
- Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Richard A Slayden
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, United States
| | - Ronald B Tjalkens
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO 80523, United States.
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2
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Dautan D, Paslawski W, Montejo SG, Doyon DC, Marangiu R, Kaplitt MG, Chen R, Dawson VL, Zhang X, Dawson TM, Svenningsson P. Gut-Initiated Alpha Synuclein Fibrils Drive Parkinson's Disease Phenotypes: Temporal Mapping of non-Motor Symptoms and REM Sleep Behavior Disorder. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.22.590542. [PMID: 38712208 PMCID: PMC11071367 DOI: 10.1101/2024.04.22.590542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Parkinson's disease (PD) is characterized by progressive motor as well as less recognized non-motor symptoms that arise often years before motor manifestation, including sleep and gastrointestinal disturbances. Despite the heavy burden on the patient's quality of life, these non-motor manifestations are poorly understood. To elucidate the temporal dynamics of the disease, we employed a mouse model involving injection of alpha-synuclein (αSyn) pre-formed fibrils (PFF) in the duodenum and antrum as a gut-brain model of Parkinsonism. Using anatomical mapping of αSyn-PFF propagation and behavioral and physiological characterizations, we unveil a correlation between post-injection time the temporal dynamics of αSyn propagation and non-motor/motor manifestations of the disease. We highlight the concurrent presence of αSyn aggregates in key brain regions, expressing acetylcholine or dopamine, involved in sleep duration, wakefulness, and particularly REM-associated atonia corresponding to REM behavioral disorder-like symptoms. This study presents a novel and in-depth exploration into the multifaceted nature of PD, unraveling the complex connections between α-synucleinopathies, gut-brain connectivity, and the emergence of non-motor phenotypes.
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Affiliation(s)
- Daniel Dautan
- Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Wojciech Paslawski
- Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Sergio G. Montejo
- Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Daniel C. Doyon
- Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Roberta Marangiu
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
- Division of Neurosurgery, Department of Neurosurgery, New-York Hospital-Cornell Medical College, New York, NY, USA
| | - Michael G. Kaplitt
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
- Division of Neurosurgery, Department of Neurosurgery, New-York Hospital-Cornell Medical College, New York, NY, USA
| | - Rong Chen
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Valina L. Dawson
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Xiaoaun Zhang
- Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Ted M. Dawson
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Per Svenningsson
- Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
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3
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Latham AS, Rocha SM, McDermott CP, Reigan P, Slayden RA, Tjalkens RB. Neuroprotective Efficacy of the Glucocorticoid Receptor Modulator PT150 in the Rotenone Mouse Model of Parkinson's Disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.12.589261. [PMID: 38659796 PMCID: PMC11042181 DOI: 10.1101/2024.04.12.589261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Parkinson's disease (PD) is the most common neurodegenerative movement disorder worldwide. Current treatments for PD largely center around dopamine replacement therapies and fail to prevent the progression of pathology, underscoring the need for neuroprotective interventions. Approaches that target neuroinflammation, which occurs prior to dopaminergic neuron (DAn) loss in the substantia nigra (SN), represent a promising therapeutic strategy. The glucocorticoid receptor (GR) has been implicated in the neuropathology of PD and modulates numerous neuroinflammatory signaling pathways in the brain. Therefore, we investigated the neuroprotective effects of the novel GR modulator, PT150, in the rotenone mouse model of PD, postulating that inhibition of glial inflammation would protect DAn and reduce accumulation of neurotoxic misfolded ⍺-synuclein protein. C57Bl/6 mice were exposed to 2.5 mg/kg/day rotenone by intraperitoneal injection for 14 days, immediately followed by oral treatment with 30 mg/kg/day or 100 mg/kg/day PT150 in the 14-day post-lesioning incubation period, during which the majority of DAn loss and α-synuclein (α-syn) accumulation occurs. Our results indicate that treatment with PT150 reduced both loss of DAn and microgliosis in the nigrostriatal pathway. Although morphologic features of astrogliosis were not attenuated, PT150 treatment promoted potentially neuroprotective activity in these cells, including increased phagocytosis of hyperphosphorylated α-syn. Ultimately, PT150 treatment reduced the loss of DAn cell bodies in the SN, but not the striatum, and prohibited intra-neuronal accumulation of α-syn. Together, these data indicate that PT150 effectively reduced SN pathology in the rotenone mouse model of PD.
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Kim S, Pajarillo E, Nyarko-Danquah I, Aschner M, Lee E. Role of Astrocytes in Parkinson's Disease Associated with Genetic Mutations and Neurotoxicants. Cells 2023; 12:622. [PMID: 36831289 PMCID: PMC9953822 DOI: 10.3390/cells12040622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 02/02/2023] [Accepted: 02/09/2023] [Indexed: 02/17/2023] Open
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons and the aggregation of Lewy bodies in the basal ganglia, resulting in movement impairment referred to as parkinsonism. However, the etiology of PD is not well known, with genetic factors accounting only for 10-15% of all PD cases. The pathogenetic mechanism of PD is not completely understood, although several mechanisms, such as oxidative stress and inflammation, have been suggested. Understanding the mechanisms of PD pathogenesis is critical for developing highly efficacious therapeutics. In the PD brain, dopaminergic neurons degenerate mainly in the basal ganglia, but recently emerging evidence has shown that astrocytes also significantly contribute to dopaminergic neuronal death. In this review, we discuss the role of astrocytes in PD pathogenesis due to mutations in α-synuclein (PARK1), DJ-1 (PARK7), parkin (PARK2), leucine-rich repeat kinase 2 (LRRK2, PARK8), and PTEN-induced kinase 1 (PINK1, PARK6). We also discuss PD experimental models using neurotoxins, such as paraquat, rotenone, 6-hydroxydopamine, and MPTP/MPP+. A more precise and comprehensive understanding of astrocytes' modulatory roles in dopaminergic neurodegeneration in PD will help develop novel strategies for effective PD therapeutics.
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Affiliation(s)
- Sanghoon Kim
- Department of Pharmaceutical Science, College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Tallahassee, FL 32307, USA
| | - Edward Pajarillo
- Department of Pharmaceutical Science, College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Tallahassee, FL 32307, USA
| | - Ivan Nyarko-Danquah
- Department of Pharmaceutical Science, College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Tallahassee, FL 32307, USA
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA
| | - Eunsook Lee
- Department of Pharmaceutical Science, College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Tallahassee, FL 32307, USA
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Chen P, Lin MH, Li YX, Huang ZJ, Rong YY, Lin QS, Ye ZC. Bexarotene enhances astrocyte phagocytosis via ABCA1-mediated pathways in a mouse model of subarachnoid hemorrhage. Exp Neurol 2022; 358:114228. [PMID: 36108713 DOI: 10.1016/j.expneurol.2022.114228] [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: 07/26/2022] [Revised: 08/31/2022] [Accepted: 09/08/2022] [Indexed: 11/04/2022]
Abstract
BACKGROUND AND PURPOSE Enhancing phagocytosis can facilitate the removal of inflammatory molecules, limit the toxicity of dead cells and debris, and promote recovery after brain injury. In this study, we aimed to explore the role of bexarotene (Bex), a retinoid X receptor (RXR) agonist, in promoting astrocyte phagocytosis and neurobehavioral recovery after subarachnoid hemorrhage (SAH). METHODS Mice SAH model was induced by pre-chiasmatic injection of blood. Modified Garcia score, novel object recognition, rotarod test, and Morris water maze were performed to assess neurological function. Immunofluorescence and electron microscopy were used to evaluate astrocyte phagocytosis in vivo. In addition, ABCA1/MEGF10&GULP1, the primary astrocyte phagocytosis pathway, were stimulated by Bex or suppressed by HX531 (a RXR antagonist) to evaluate their impacts on astrocyte phagocytosis and neurological recovery. RESULTS Astrocytes phagocytosis of blood components were observed in mice after SAH induction, which is further increased by Bex treatment. Bex dramatically attenuated neuroinflammation, reduced brain edema, improved early neurological performance and promoted neurocognitive recovery. Meanwhile, Bex decreased neurotoxic reactive astrocytes and preserved neurogenesis after SAH. Bex increased the expression of astrocyte phagocytosis-related proteins ABCA1, MEGF10, and GULP1. Bex also increased the lysosomal processing of engulfed blood components in astrocytes. Moreover, Bex significantly promoted astrocytes to phagocytize debris in vitro by increasing the expression of ABCA1, MEGF10 and GULP1, while HX531 inhibited astrocyte phagocytosis and decreased these protein levels. CONCLUSIONS Bex enhanced astrocyte phagocytosis through the ABCA1-mediated pathways, and promoted neurobehavior recovery in mice after SAH induction.
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Affiliation(s)
- Ping Chen
- Department of Anesthesiology, Anesthesiology Research Institute, the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, China; Fujian Provincial Key Laboratory of Brain Aging and Neurodegenerative Diseases, The School of Basic Medical Sciences, Fujian Medical University, China
| | - Mou-Hui Lin
- Fujian Provincial Key Laboratory of Brain Aging and Neurodegenerative Diseases, The School of Basic Medical Sciences, Fujian Medical University, China
| | - Yu-Xi Li
- Fujian Provincial Key Laboratory of Brain Aging and Neurodegenerative Diseases, The School of Basic Medical Sciences, Fujian Medical University, China
| | - Zhi-Jie Huang
- Fujian Provincial Key Laboratory of Brain Aging and Neurodegenerative Diseases, The School of Basic Medical Sciences, Fujian Medical University, China
| | - Yu-You Rong
- Fujian Provincial Key Laboratory of Brain Aging and Neurodegenerative Diseases, The School of Basic Medical Sciences, Fujian Medical University, China
| | - Qing-Song Lin
- Department of Neurosurgery, Neurosurgery Research Institute, the First Affiliated Hospital, Fujian Medical University, Fuzhou, Fujian, China.
| | - Zu-Cheng Ye
- Fujian Provincial Key Laboratory of Brain Aging and Neurodegenerative Diseases, The School of Basic Medical Sciences, Fujian Medical University, China.
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Pathogenesis of α-Synuclein in Parkinson's Disease: From a Neuron-Glia Crosstalk Perspective. Int J Mol Sci 2022; 23:ijms232314753. [PMID: 36499080 PMCID: PMC9739123 DOI: 10.3390/ijms232314753] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Revised: 11/21/2022] [Accepted: 11/22/2022] [Indexed: 11/29/2022] Open
Abstract
Parkinson's disease (PD) is a progressive neurodegenerative disorder. The classical behavioral defects of PD patients involve motor symptoms such as bradykinesia, tremor, and rigidity, as well as non-motor symptoms such as anosmia, depression, and cognitive impairment. Pathologically, the progressive loss of dopaminergic (DA) neurons in the substantia nigra (SN) and the accumulation of α-synuclein (α-syn)-composed Lewy bodies (LBs) and Lewy neurites (LNs) are key hallmarks. Glia are more than mere bystanders that simply support neurons, they actively contribute to almost every aspect of neuronal development and function; glial dysregulation has been implicated in a series of neurodegenerative diseases including PD. Importantly, amounting evidence has added glial activation and neuroinflammation as new features of PD onset and progression. Thus, gaining a better understanding of glia, especially neuron-glia crosstalk, will not only provide insight into brain physiology events but also advance our knowledge of PD pathologies. This review addresses the current understanding of α-syn pathogenesis in PD, with a focus on neuron-glia crosstalk. Particularly, the transmission of α-syn between neurons and glia, α-syn-induced glial activation, and feedbacks of glial activation on DA neuron degeneration are thoroughly discussed. In addition, α-syn aggregation, iron deposition, and glial activation in regulating DA neuron ferroptosis in PD are covered. Lastly, we summarize the preclinical and clinical therapies, especially targeting glia, in PD treatments.
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P2X7 Receptor and Purinergic Signaling: Orchestrating Mitochondrial Dysfunction in Neurodegenerative Diseases. eNeuro 2022; 9:9/6/ENEURO.0092-22.2022. [PMID: 36376084 PMCID: PMC9665882 DOI: 10.1523/eneuro.0092-22.2022] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 07/14/2022] [Accepted: 08/09/2022] [Indexed: 11/15/2022] Open
Abstract
Mitochondrial dysfunction is one of the basic hallmarks of cellular pathology in neurodegenerative diseases. Since the metabolic activity of neurons is highly dependent on energy supply, nerve cells are especially vulnerable to impaired mitochondrial function. Besides providing oxidative phosphorylation, mitochondria are also involved in controlling levels of second messengers such as Ca2+ ions and reactive oxygen species (ROS). Interestingly, the critical role of mitochondria as producers of ROS is closely related to P2XR purinergic receptors, the activity of which is modulated by free radicals. Here, we review the relationships between the purinergic signaling system and affected mitochondrial function. Purinergic signaling regulates numerous vital biological processes in the CNS. The two main purines, ATP and adenosine, act as excitatory and inhibitory neurotransmitters, respectively. Current evidence suggests that purinergic signaling best explains how neuronal activity is related to neuronal electrical activity and energy homeostasis, especially in the development of Alzheimer's and Parkinson's diseases. In this review, we focus on the mechanisms underlying the involvement of the P2RX7 purinoreceptor in triggering mitochondrial dysfunction during the development of neurodegenerative disorders. We also summarize various avenues by which the purine signaling pathway may trigger metabolic dysfunction contributing to neuronal death and the inflammatory activation of glial cells. Finally, we discuss the potential role of the purinergic system in the search for new therapeutic approaches to treat neurodegenerative diseases.
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Broome ST, Musumeci G, Castorina A. PACAP and VIP Mitigate Rotenone-Induced Inflammation in BV-2 Microglial Cells. J Mol Neurosci 2022; 72:2163-2175. [PMID: 35199308 PMCID: PMC9726775 DOI: 10.1007/s12031-022-01968-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 01/05/2022] [Indexed: 12/16/2022]
Abstract
Rotenone is a commercial pesticide commonly used to model Parkinson's disease (PD) due to its ability to induce dopaminergic degeneration. Studies have confirmed that rotenone causes microglial activation, which seems to contribute to the toxic effects seen in rodent models. Pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP) are two structurally related neuropeptides that have robust neuroprotective and anti-inflammatory properties. However, their ability to regulate microglial activity in response to rotenone is not fully understood. Using rotenone as an inflammatory stimulus, we tested whether PACAP or VIP could mitigate microglial activation in BV2 microglial cells. Rotenone dose-dependently reduced cell viability and the percentage of apoptotic cells. It also increased the release of nitric oxide (NO) in culture media and the expression of microglial activation markers and pro-inflammatory markers, including CD11b, MMP-9 and IL-6, and heightened the endogenous levels of PACAP and its preferring receptor PAC1. Co-treatment with PACAP or VIP prevented rotenone-induced increase of NO, CD11b, MMP-9 and IL-6. These results indicate that both PACAP and VIP are able to prevent the pro-inflammatory effects of rotenone in BV2 cells, supporting the idea that these molecules can have therapeutic value in slowing down PD progression.
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Affiliation(s)
- Sarah Thomas Broome
- Laboratory of Cellular and Molecular Neuroscience (LCMN), School of Life Sciences, Faculty of Science, University of Technology Sydney, PO Box 123, Broadway, NSW, 2007, Australia
| | - Giuseppe Musumeci
- Section of Human Anatomy, Histology and Movement Science, Department of Biomedical and Biotechnological Sciences, University of Catania, via S. Sofia, 87, 95123, Catania, Italy
| | - Alessandro Castorina
- Laboratory of Cellular and Molecular Neuroscience (LCMN), School of Life Sciences, Faculty of Science, University of Technology Sydney, PO Box 123, Broadway, NSW, 2007, Australia.
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Awa S, Suzuki G, Masuda-Suzukake M, Nonaka T, Saito M, Hasegawa M. Phosphorylation of endogenous α-synuclein induced by extracellular seeds initiates at the pre-synaptic region and spreads to the cell body. Sci Rep 2022; 12:1163. [PMID: 35064139 PMCID: PMC8782830 DOI: 10.1038/s41598-022-04780-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 12/30/2021] [Indexed: 11/16/2022] Open
Abstract
Accumulation of phosphorylated α-synuclein aggregates has been implicated in several diseases, such as Parkinson's disease (PD) and dementia with Lewy bodies (DLB), and is thought to spread in a prion-like manner. Elucidating the mechanisms of prion-like transmission of α-synuclein is important for the development of therapies for these diseases, but little is known about the details. Here, we injected α-synuclein fibrils into the brains of wild-type mice and examined the early phase of the induction of phosphorylated α-synuclein accumulation. We found that phosphorylated α-synuclein appeared within a few days after the intracerebral injection. It was observed initially in presynaptic regions and subsequently extended its localization to axons and cell bodies. These results suggest that extracellular α-synuclein fibrils are taken up into the presynaptic region and seed-dependently convert the endogenous normal α-synuclein that is abundant there to an abnormal phosphorylated form, which is then transported through the axon to the cell body.
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Affiliation(s)
- Shiori Awa
- Department of Brain and Neurosciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan.,Department of Biosciences, College of Humanities and Sciences, Nihon University, Tokyo, Japan.,Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Genjiro Suzuki
- Department of Brain and Neurosciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan.
| | - Masami Masuda-Suzukake
- Department of Brain and Neurosciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Takashi Nonaka
- Department of Brain and Neurosciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Minoru Saito
- Department of Biosciences, College of Humanities and Sciences, Nihon University, Tokyo, Japan.,Department of Correlative Study in Physics and Chemistry, Graduate School of Integrated Basic Sciences, Nihon University, Tokyo, Japan
| | - Masato Hasegawa
- Department of Brain and Neurosciences, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan.
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