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Chen L, Chehade HD, Chu HY. Motor cortical neuronal hyperexcitability associated with α-synuclein aggregation. NPJ Parkinsons Dis 2025; 11:18. [PMID: 39809792 PMCID: PMC11733020 DOI: 10.1038/s41531-024-00867-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2024] [Accepted: 12/27/2024] [Indexed: 01/16/2025] Open
Abstract
ΑBSTRACT: In Parkinson's disease (PD), Lewy pathology deposits in the cerebral cortex, but how the pathology disrupts cortical circuit integrity and function remains poorly understood. To begin to address this question, we injected α-synuclein (αSyn) preformed fibrils (PFFs) into the dorsolateral striatum of mice to seed αSyn pathology in the cortical cortex and induce degeneration of midbrain dopaminergic neurons. We reported that αSyn aggregates accumulate in the motor cortex in a layer- and cell-subtype-specific pattern. Specifically, αSyn aggregates-bearing intratelencephalic neurons (ITNs) showed hyperexcitability, increased input resistance, and decreased cell capacitance, which were associated with impaired HCN channel function. Morphologically, the αSyn aggregates-bearing ITNs showed shrinkage of cell bodies and loss of dendritic spines. Last, we showed that partial dopamine depletion is not sufficient to alter thalamocortical transmission to cortical pyramidal neurons. Our results provide a novel mechanistic understanding of cortical circuit dysfunction in PD.
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Affiliation(s)
- Liqiang Chen
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, 20852, USA
- Department of Neurodegenerative Science, Van Andel Institute, Grand Rapids, MI, 49503, USA
- Department of Pharmacology and Physiology, Georgetown University of Medical Center, Washington, DC, 20007, USA
| | - Hiba Douja Chehade
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, 20852, USA
- Department of Neurodegenerative Science, Van Andel Institute, Grand Rapids, MI, 49503, USA
- Department of Pharmacology and Physiology, Georgetown University of Medical Center, Washington, DC, 20007, USA
| | - Hong-Yuan Chu
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, 20852, USA.
- Department of Neurodegenerative Science, Van Andel Institute, Grand Rapids, MI, 49503, USA.
- Department of Pharmacology and Physiology, Georgetown University of Medical Center, Washington, DC, 20007, USA.
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2
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Chen L, Chehade HD, Chu HY. Motor Cortical Neuronal Hyperexcitability Associated with α-Synuclein Aggregation. RESEARCH SQUARE 2024:rs.3.rs-4797540. [PMID: 39281856 PMCID: PMC11398582 DOI: 10.21203/rs.3.rs-4797540/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/18/2024]
Abstract
Dysfunction of the cerebral cortex is thought to underlie motor and cognitive impairments in Parkinson disease (PD). While cortical function is known to be suppressed by abnormal basal ganglia output following dopaminergic degeneration, it remains to be determined how the deposition of Lewy pathology disrupts cortical circuit integrity and function. Moreover, it is also unknown whether cortical Lewy pathology and midbrain dopaminergic degeneration interact to disrupt cortical function in late-stage. To begin to address these questions, we injected α-synuclein (αSyn) preformed fibrils (PFFs) into the dorsolateral striatum of mice to seed αSyn pathology in the cortical cortex and induce degeneration of midbrain dopaminergic neurons. Using this model system, we reported that αSyn aggregates accumulate in the motor cortex in a layer- and cell-subtype-specific pattern. Particularly, intratelencephalic neurons (ITNs) showed earlier accumulation and greater extent of αSyn aggregates relative to corticospinal neurons (CSNs). Moreover, we demonstrated that the intrinsic excitability and inputs resistance of αSyn aggregates-bearing ITNs in the secondary motor cortex (M2) are increased, along with a noticeable shrinkage of cell bodies and loss of dendritic spines. Last, neither the intrinsic excitability of CSNs nor their thalamocortical input was altered by a partial striatal dopamine depletion associated with αSyn pathology. Our results documented motor cortical neuronal hyperexcitability associated with αSyn aggregation and provided a novel mechanistic understanding of cortical circuit dysfunction in PD.
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Affiliation(s)
- Liqiang Chen
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, 20852, United States
- Department of Neurodegenerative Science, Van Andel Institute, Grand Rapids, MI 49503, United States
- Department of Pharmacology and Physiology, Georgetown University of Medical Center, Washington DC, 20007, United States
| | - Hiba Douja Chehade
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, 20852, United States
- Department of Neurodegenerative Science, Van Andel Institute, Grand Rapids, MI 49503, United States
- Department of Pharmacology and Physiology, Georgetown University of Medical Center, Washington DC, 20007, United States
| | - Hong-Yuan Chu
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, 20852, United States
- Department of Neurodegenerative Science, Van Andel Institute, Grand Rapids, MI 49503, United States
- Department of Pharmacology and Physiology, Georgetown University of Medical Center, Washington DC, 20007, United States
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3
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Chen L, Chehade HD, Chu HY. Motor Cortical Neuronal Hyperexcitability Associated with α-Synuclein Aggregation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.24.604995. [PMID: 39091827 PMCID: PMC11291145 DOI: 10.1101/2024.07.24.604995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/04/2024]
Abstract
Dysfunction of the cerebral cortex is thought to underlie motor and cognitive impairments in Parkinson disease (PD). While cortical function is known to be suppressed by abnormal basal ganglia output following dopaminergic degeneration, it remains to be determined how the deposition of Lewy pathology disrupts cortical circuit integrity and function. Moreover, it is also unknown whether cortical Lewy pathology and midbrain dopaminergic degeneration interact to disrupt cortical function in late-stage. To begin to address these questions, we injected α-synuclein (αSyn) preformed fibrils (PFFs) into the dorsolateral striatum of mice to seed αSyn pathology in the cortical cortex and induce degeneration of midbrain dopaminergic neurons. Using this model system, we reported that αSyn aggregates accumulate in the motor cortex in a layer- and cell-subtype-specific pattern. Particularly, intratelencephalic neurons (ITNs) showed earlier accumulation and greater extent of αSyn aggregates relative to corticospinal neurons (CSNs). Moreover, we demonstrated that the intrinsic excitability and inputs resistance of αSyn aggregates-bearing ITNs in the secondary motor cortex (M2) are increased, along with a noticeable shrinkage of cell bodies and loss of dendritic spines. Last, neither the intrinsic excitability of CSNs nor their thalamocortical input was altered by a partial striatal dopamine depletion associated with αSyn pathology. Our results documented motor cortical neuronal hyperexcitability associated with αSyn aggregation and provided a novel mechanistic understanding of cortical circuit dysfunction in PD.
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Affiliation(s)
- Liqiang Chen
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, 20852, United States
- Department of Neurodegenerative Science, Van Andel Institute, Grand Rapids, MI 49503, United States
- Department of Pharmacology and Physiology, Georgetown University of Medical Center, Washington DC, 20007, United States
| | - Hiba Douja Chehade
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, 20852, United States
- Department of Neurodegenerative Science, Van Andel Institute, Grand Rapids, MI 49503, United States
- Department of Pharmacology and Physiology, Georgetown University of Medical Center, Washington DC, 20007, United States
| | - Hong-Yuan Chu
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, 20852, United States
- Department of Neurodegenerative Science, Van Andel Institute, Grand Rapids, MI 49503, United States
- Department of Pharmacology and Physiology, Georgetown University of Medical Center, Washington DC, 20007, United States
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4
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Chiu WH, Wattad N, Goldberg JA. Ion channel dysregulation and cellular adaptations to alpha-synuclein in stressful pacemakers of the parkinsonian brainstem. Pharmacol Ther 2024; 260:108683. [PMID: 38950869 DOI: 10.1016/j.pharmthera.2024.108683] [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: 01/23/2024] [Revised: 06/21/2024] [Accepted: 06/28/2024] [Indexed: 07/03/2024]
Abstract
Parkinson's disease (PD) is diagnosed by its cardinal motor symptoms that are associated with the loss of dopamine neurons in the substantia nigra pars compacta (SNc). However, PD patients suffer from various non-motor symptoms years before diagnosis. These prodromal symptoms are thought to be associated with the appearance of Lewy body pathologies (LBP) in brainstem regions such as the dorsal motor nucleus of the vagus (DMV), the locus coeruleus (LC) and others. The neurons in these regions that are vulnerable to LBP are all slow autonomous pacemaker neurons that exhibit elevated oxidative stress due to their perpetual influx of Ca2+ ions. Aggregation of toxic α-Synuclein (aSyn) - the main constituent of LBP - during the long prodromal period challenges these vulnerable neurons, presumably altering their biophysics and physiology. In contrast to pathophysiology of late stage parkinsonism which is well-documented, little is known about the pathophysiology of the brainstem during prodromal PD. In this review, we discuss ion channel dysregulation associated with aSyn aggregation in brainstem pacemaker neurons and their cellular responses to them. While toxic aSyn elevates oxidative stress in SNc and LC pacemaker neurons and exacerbates their phenotype, DMV neurons mount an adaptive response that mitigates the oxidative stress. Ion channel dysregulation and cellular adaptations may be the drivers of the prodromal symptoms of PD. For example, selective targeting of toxic aSyn to DMV pacemakers, elevates the surface density of K+ channels, which slows their firing rate, resulting in reduced parasympathetic tone to the gastrointestinal tract, which resembles the prodromal PD symptoms of dysphagia and constipation. The divergent responses of SNc & LC vs. DMV pacemaker neurons may explain why the latter outlive the former despite presenting LBPs earlier. Elucidation the brainstem pathophysiology of prodromal PD could pave the way for physiological biomarkers, earlier diagnosis and novel neuroprotective therapies for PD.
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Affiliation(s)
- Wei-Hua Chiu
- Department of Neurology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Nadine Wattad
- Department of Medical Neurobiology, Institute of Medical Research Israel - Canada, The Faculty of Medicine, The Hebrew University of Jerusalem, 9112102 Jerusalem, Israel
| | - Joshua A Goldberg
- Department of Medical Neurobiology, Institute of Medical Research Israel - Canada, The Faculty of Medicine, The Hebrew University of Jerusalem, 9112102 Jerusalem, Israel; Department of Neuroscience, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA.
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de Souza JGV, de Souza DP, da Silva CAA, Martins Sá RW, Paton JFR, da Silva MP, Moraes DJA. Electrophysiological Properties and Morphology of Cardiac and Pulmonary Motoneurons within the Dorsal Motor Nucleus of the Vagus of Rats. Neuroscience 2024; 551:153-165. [PMID: 38821242 DOI: 10.1016/j.neuroscience.2024.05.038] [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: 02/16/2024] [Revised: 05/24/2024] [Accepted: 05/27/2024] [Indexed: 06/02/2024]
Abstract
The dorsal motor nucleus of the vagus (DMV) contains parasympathetic motoneurons that project to the heart and lungs. These motoneurons control ventricular excitability/contractility and airways secretions/blood flow, respectively. However, their electrophysiological properties, morphology and synaptic input activity remain unknown. One important ionic current described in DMV motoneurons controlling their electrophysiological behaviour is the A-type mediated by voltage-dependent K+ (Kv) channels. Thus, we compared the electrophysiological properties, synaptic activity, morphology, A-type current density, and single cell expression of Kv subunits, that contribute to macroscopic A-type currents, between DMV motoneurons projecting to either the heart or lungs of adult male rats. Using retrograde labelling, we visualized distinct DMV motoneurons projecting to the heart or lungs in acutely prepared medullary slices. Subsequently, whole cell recordings, morphological reconstruction and single motoneuron qRT-PCR studies were performed. DMV pulmonary motoneurons were more depolarized, electrically excitable, presented higher membrane resistance, broader action potentials and received greater excitatory synaptic inputs compared to cardiac DMV motoneurons. These differences were in part due to highly branched dendritic complexity and lower magnitude of A-type K+ currents. By evaluating expression of channels that mediate A-type currents from single motoneurons, we demonstrated a lower level of Kv4.2 in pulmonary versus cardiac motoneurons, whereas Kv4.3 and Kv1.4 levels were similar. Thus, with the distinct electrical, morphological, and molecular properties of DMV cardiac and pulmonary motoneurons, we surmise that these cells offer a new vista of opportunities for genetic manipulation providing improvement of parasympathetic function in cardiorespiratory diseases such heart failure and asthma.
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Affiliation(s)
- Júlia G V de Souza
- School of Medicine of Ribeirão Preto, Department of Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Daniel P de Souza
- School of Medicine of Ribeirão Preto, Department of Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Carlos A A da Silva
- School of Medicine of Ribeirão Preto, Department of Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Renato W Martins Sá
- School of Medicine of Ribeirão Preto, Department of Physiology, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Julian F R Paton
- Manaaki Manawa - The Centre for Heart Research, Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Melina P da Silva
- Department of Biophysics, Paulista School of Medicine, Federal University of São Paulo, São Paulo, SP, Brazil.
| | - Davi J A Moraes
- Department of Physiology and Biophysics, Biomedical Science Institute, University of São Paulo, São Paulo, SP, Brazil.
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Chen X, Feng Y, Quinn RJ, Pountney DL, Richardson DR, Mellick GD, Ma L. Potassium Channels in Parkinson's Disease: Potential Roles in Its Pathogenesis and Innovative Molecular Targets for Treatment. Pharmacol Rev 2023; 75:758-788. [PMID: 36918260 DOI: 10.1124/pharmrev.122.000743] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 01/05/2023] [Accepted: 03/07/2023] [Indexed: 03/16/2023] Open
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder characterized by selective loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) region of the midbrain. The loss of neurons results in a subsequent reduction of dopamine in the striatum, which underlies the core motor symptoms of PD. To date, there are no effective treatments to stop, slow, or reverse the pathologic progression of dopaminergic neurodegeneration. This unfortunate predicament is because of the current early stages in understanding the biologic targets and pathways involved in PD pathogenesis. Ion channels have become emerging targets for new therapeutic development for PD due to their essential roles in neuronal function and neuroinflammation. Potassium channels are the most prominent ion channel family and have been shown to be critically important in PD pathology because of their roles in modulating neuronal excitability, neurotransmitter release, synaptic transmission, and neuroinflammation. In this review, members of the subfamilies of voltage-gated K+ channels, inward rectifying K+ channels, and Ca2+-activated K+ channels are described. Evidence of the role of these channels in PD etiology is discussed together with the latest views on related pathologic mechanisms and their potential as biologic targets for developing neuroprotective drugs for PD. SIGNIFICANCE STATEMENT: Parkinson's disease (PD) is the second most common neurodegenerative disorder, featuring progressive degeneration of dopaminergic neurons in the midbrain. It is a multifactorial disease involving multiple risk factors and complex pathobiological mechanisms. Mounting evidence suggests that ion channels play vital roles in the pathogenesis and progression of PD by regulating neuronal excitability and immune cell function. Therefore, they have become "hot" biological targets for PD, as demonstrated by multiple clinical trials of drug candidates targeting ion channels for PD therapy.
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Affiliation(s)
- Xiaoyi Chen
- School of Environment and Science (Y.F., D.R.R., G.D.M., L.M.) and Centre for Cancer Cell Biology and Drug Discovery (D.R.R.), Griffith Institute for Drug Discovery (X.C., Y.F., R.J.Q., D.R.R., G.D.M., L.M.), Griffith University, Nathan, Brisbane, Queensland, Australia; and School of Pharmacy and Medical Science, Griffith University, Gold Coast, Queenslandstate, Australia (D.L.P.)
| | - Yunjiang Feng
- School of Environment and Science (Y.F., D.R.R., G.D.M., L.M.) and Centre for Cancer Cell Biology and Drug Discovery (D.R.R.), Griffith Institute for Drug Discovery (X.C., Y.F., R.J.Q., D.R.R., G.D.M., L.M.), Griffith University, Nathan, Brisbane, Queensland, Australia; and School of Pharmacy and Medical Science, Griffith University, Gold Coast, Queenslandstate, Australia (D.L.P.)
| | - Ronald J Quinn
- School of Environment and Science (Y.F., D.R.R., G.D.M., L.M.) and Centre for Cancer Cell Biology and Drug Discovery (D.R.R.), Griffith Institute for Drug Discovery (X.C., Y.F., R.J.Q., D.R.R., G.D.M., L.M.), Griffith University, Nathan, Brisbane, Queensland, Australia; and School of Pharmacy and Medical Science, Griffith University, Gold Coast, Queenslandstate, Australia (D.L.P.)
| | - Dean L Pountney
- School of Environment and Science (Y.F., D.R.R., G.D.M., L.M.) and Centre for Cancer Cell Biology and Drug Discovery (D.R.R.), Griffith Institute for Drug Discovery (X.C., Y.F., R.J.Q., D.R.R., G.D.M., L.M.), Griffith University, Nathan, Brisbane, Queensland, Australia; and School of Pharmacy and Medical Science, Griffith University, Gold Coast, Queenslandstate, Australia (D.L.P.)
| | - Des R Richardson
- School of Environment and Science (Y.F., D.R.R., G.D.M., L.M.) and Centre for Cancer Cell Biology and Drug Discovery (D.R.R.), Griffith Institute for Drug Discovery (X.C., Y.F., R.J.Q., D.R.R., G.D.M., L.M.), Griffith University, Nathan, Brisbane, Queensland, Australia; and School of Pharmacy and Medical Science, Griffith University, Gold Coast, Queenslandstate, Australia (D.L.P.)
| | - George D Mellick
- School of Environment and Science (Y.F., D.R.R., G.D.M., L.M.) and Centre for Cancer Cell Biology and Drug Discovery (D.R.R.), Griffith Institute for Drug Discovery (X.C., Y.F., R.J.Q., D.R.R., G.D.M., L.M.), Griffith University, Nathan, Brisbane, Queensland, Australia; and School of Pharmacy and Medical Science, Griffith University, Gold Coast, Queenslandstate, Australia (D.L.P.)
| | - Linlin Ma
- School of Environment and Science (Y.F., D.R.R., G.D.M., L.M.) and Centre for Cancer Cell Biology and Drug Discovery (D.R.R.), Griffith Institute for Drug Discovery (X.C., Y.F., R.J.Q., D.R.R., G.D.M., L.M.), Griffith University, Nathan, Brisbane, Queensland, Australia; and School of Pharmacy and Medical Science, Griffith University, Gold Coast, Queenslandstate, Australia (D.L.P.)
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Cheng Y, Tong Q, Yuan Y, Song X, Jiang W, Wang Y, Li W, Li Y, Zhang K. α-Synuclein induces prodromal symptoms of Parkinson's disease via activating TLR2/MyD88/NF-κB pathway in Schwann cells of vagus nerve in a rat model. J Neuroinflammation 2023; 20:36. [PMID: 36788559 PMCID: PMC9926693 DOI: 10.1186/s12974-023-02720-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 02/03/2023] [Indexed: 02/16/2023] Open
Abstract
BACKGROUND Increasing evidence suggests that patients with Parkinson's disease (PD) present with peripheral autonomic dysfunction (AutD) that even precedes motor deficits, through which α-synuclein can spread to the central nervous system. However, the pathological mechanisms underlying AutD in prodromal PD remain unclear. Here, we investigated the role of α-synuclein and its interplay with the activation of Schwann cells (SCs) of the vagus nerve in AutD. METHODS Rats were subjected to injection with adeno-associated viruses containing the human mutated A53T gene (AAV-A53T) or an empty vector into the left cervical vagus nerve and evaluated for gastrointestinal symptoms, locomotor functions, intestinal blood flow, and nerve electrophysiology. Further, we examined the impact of α-synucleinopathy on vagus nerves, SCs, and central nervous system neurons using electron microscopy, immunofluorescence, immunohistochemistry, and western blot. Finally, the role of Toll-like receptor 2 (TLR2) in regulating the neuroinflammation in the vagus nerve via MyD88 and NF-κB pathway was determined using genetic knockdown. RESULTS We found that rats injected with AAV-A53T in the vagus nerve exhibited prominent signs of AutD, preceding the onset of motor deficits and central dopaminergic abnormalities by at least 3 months, which could serve as a model for prodromal PD. In addition, reduced intestinal blood flow and decreased nerve conduction velocity were identified in AAV-A53T-injected rats, accompanied by disrupted myelin sheaths and swollen SCs in the vagus nerve. Furthermore, our data demonstrated that p-α-synuclein was deposited in SCs but not in axons, activating the TLR2/MyD88/NF-κB signaling pathway and leading to neuroinflammatory responses. In contrast, silencing the TLR2 gene not only reduced inflammatory cytokine expression but also ameliorated vagal demyelination and secondary axonal loss, consequently improving autonomic function in rats. CONCLUSIONS These observations suggest that overexpression of α-synuclein in the vagus nerve can induce symptoms of AutD in prodromal PD, and provide support for a deeper understanding of the pathological mechanisms underlying AutD and the emergence of effective therapeutic strategies for PD.
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Affiliation(s)
- Yue Cheng
- grid.412676.00000 0004 1799 0784Department of Neurology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029 China
| | - Qing Tong
- grid.412676.00000 0004 1799 0784Department of Neurology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029 China
| | - Yongsheng Yuan
- grid.412676.00000 0004 1799 0784Department of Neurology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029 China
| | - Xinna Song
- grid.412676.00000 0004 1799 0784Department of Neurology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029 China
| | - Wenwen Jiang
- grid.412676.00000 0004 1799 0784Department of Neurology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029 China
| | - Yueping Wang
- grid.89957.3a0000 0000 9255 8984Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, Nanjing, 211116 China
| | - Wenjie Li
- grid.89957.3a0000 0000 9255 8984Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, Nanjing, 211116 China
| | - Yangxia Li
- grid.412676.00000 0004 1799 0784Department of Neurology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029 China
| | - Kezhong Zhang
- Department of Neurology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China.
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Helwig M, Ulusoy A, Rollar A, O’Sullivan SA, Lee SSL, Aboutalebi H, Pinto-Costa R, Jevans B, Klinkenberg M, Di Monte DA. Neuronal hyperactivity-induced oxidant stress promotes in vivo α-synuclein brain spreading. SCIENCE ADVANCES 2022; 8:eabn0356. [PMID: 36044566 PMCID: PMC9432848 DOI: 10.1126/sciadv.abn0356] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 07/15/2022] [Indexed: 05/31/2023]
Abstract
Interneuronal transfer and brain spreading of pathogenic proteins are features of neurodegenerative diseases. Pathophysiological conditions and mechanisms affecting this spreading remain poorly understood. This study investigated the relationship between neuronal activity and interneuronal transfer of α-synuclein, a Parkinson-associated protein, and elucidated mechanisms underlying this relationship. In a mouse model of α-synuclein brain spreading, hyperactivity augmented and hypoactivity attenuated protein transfer. Important features of neuronal hyperactivity reported here were an exacerbation of oxidative and nitrative reactions, pronounced accumulation of nitrated α-synuclein, and increased protein aggregation. Data also pointed to mitochondria as key targets and likely sources of reactive oxygen and nitrogen species within hyperactive neurons. Rescue experiments designed to counteract the increased burden of reactive oxygen species reversed hyperactivity-induced α-synuclein nitration, aggregation, and interneuronal transfer, providing first evidence of a causal link between these pathological effects of neuronal stimulation and indicating a mechanistic role of oxidant stress in hyperactivity-induced α-synuclein spreading.
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Affiliation(s)
- Michael Helwig
- German Center for Neurodegenerative Diseases (DZNE), Bonn 53127, Germany
| | - Ayse Ulusoy
- German Center for Neurodegenerative Diseases (DZNE), Bonn 53127, Germany
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Angela Rollar
- German Center for Neurodegenerative Diseases (DZNE), Bonn 53127, Germany
| | | | - Shirley S. L. Lee
- German Center for Neurodegenerative Diseases (DZNE), Bonn 53127, Germany
| | - Helia Aboutalebi
- German Center for Neurodegenerative Diseases (DZNE), Bonn 53127, Germany
| | - Rita Pinto-Costa
- German Center for Neurodegenerative Diseases (DZNE), Bonn 53127, Germany
| | - Benjamin Jevans
- German Center for Neurodegenerative Diseases (DZNE), Bonn 53127, Germany
| | | | - Donato A. Di Monte
- German Center for Neurodegenerative Diseases (DZNE), Bonn 53127, Germany
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
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Burke S, Trudeau LE. Axonal Domain Structure as a Putative Identifier of Neuron-Specific Vulnerability to Oxidative Stress in Cultured Neurons. eNeuro 2022; 9:ENEURO.0139-22.2022. [PMID: 36192156 PMCID: PMC9595591 DOI: 10.1523/eneuro.0139-22.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 08/30/2022] [Accepted: 09/16/2022] [Indexed: 12/15/2022] Open
Abstract
Several populations of neurons are purported to degenerate in Parkinson's disease (PD). One current hypothesis suggests that vulnerable neurons in PD share common characteristics including projecting to voluminous territories and having extremely long and branched axonal domains with large numbers of neurotransmitter release sites. In this study, we used a mouse in vitro culture system to compare the axonal domain of neuronal populations suspected to be vulnerable in PD to that of neuronal populations considered at a lesser risk. In the first category, we included dopamine (DA) neurons of the substantia nigra, noradrenergic neurons of the locus coeruleus (LC), serotonin neurons of the raphe nuclei (R), and cholinergic neurons of the dorsal motor nucleus of the vagus (DMV). In the second category, we included DA neurons of the ventral tegmental area, cholinergic neurons of the hypoglossal nucleus, and cholinergic interneurons of the dorsal striatum. Validating their differential vulnerability, we find that, when compared with neurons presumed to be resilient in PD, a larger proportion of neurons presumed to be vulnerable in PD degenerate in response to cell stress induced by hydrogen peroxide. We also find that they are endowed with larger axonal domains, that are more complex, have more axonal varicosities with a higher proportion of varicosities that are positive for synaptotagmin 1 (Syt-1). Notwithstanding the obvious limitations related to the dissection of small brain nuclei and to the growth of these neurons in vitro, these findings support the hypothesis that axonal domain structure is a key characteristic of neuronal vulnerability to oxidative stress.
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Affiliation(s)
- Samuel Burke
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, Quebec, H3T 1J4, Canada
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montreal, Quebec, H3T 1J4, Canada
- Neural Signaling and Circuitry Research Group (SNC), Montréal, Quebec, H3T 1J4, Canada
- Center for Interdisciplinary Research on the Brain and Learning (CIRCA), Montréal, Quebec, H3T 1J4
| | - Louis-Eric Trudeau
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montreal, Quebec, H3T 1J4, Canada
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montreal, Quebec, H3T 1J4, Canada
- Neural Signaling and Circuitry Research Group (SNC), Montréal, Quebec, H3T 1J4, Canada
- Center for Interdisciplinary Research on the Brain and Learning (CIRCA), Montréal, Quebec, H3T 1J4
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Kulkarni AS, Burns MR, Brundin P, Wesson DW. Linking α-synuclein-induced synaptopathy and neural network dysfunction in early Parkinson's disease. Brain Commun 2022; 4:fcac165. [PMID: 35822101 PMCID: PMC9272065 DOI: 10.1093/braincomms/fcac165] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 03/11/2022] [Accepted: 06/20/2022] [Indexed: 01/18/2023] Open
Abstract
The prodromal phase of Parkinson's disease is characterized by aggregation of the misfolded pathogenic protein α-synuclein in select neural centres, co-occurring with non-motor symptoms including sensory and cognitive loss, and emotional disturbances. It is unclear whether neuronal loss is significant during the prodrome. Underlying these symptoms are synaptic impairments and aberrant neural network activity. However, the relationships between synaptic defects and network-level perturbations are not established. In experimental models, pathological α-synuclein not only impacts neurotransmission at the synaptic level, but also leads to changes in brain network-level oscillatory dynamics-both of which likely contribute to non-motor deficits observed in Parkinson's disease. Here we draw upon research from both human subjects and experimental models to propose a 'synapse to network prodrome cascade' wherein before overt cell death, pathological α-synuclein induces synaptic loss and contributes to aberrant network activity, which then gives rise to prodromal symptomology. As the disease progresses, abnormal patterns of neural activity ultimately lead to neuronal loss and clinical progression of disease. Finally, we outline goals and research needed to unravel the basis of functional impairments in Parkinson's disease and other α-synucleinopathies.
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Affiliation(s)
- Aishwarya S Kulkarni
- Department of Pharmacology & Therapeutics, University of Florida, 1200 Newell Dr, Gainesville, FL 32610, USA
| | - Matthew R Burns
- Department of Neurology, University of Florida, 1200 Newell Dr, Gainesville, FL 32610, USA
- Norman Fixel Institute for Neurological Disorders, University of Florida, 1200 Newell Dr, Gainesville, FL 32610, USA
| | - Patrik Brundin
- Pharma Research and Early Development (pRED), F. Hoffman-La Roche, Little Falls, NJ, USA
| | - Daniel W Wesson
- Department of Pharmacology & Therapeutics, University of Florida, 1200 Newell Dr, Gainesville, FL 32610, USA
- Norman Fixel Institute for Neurological Disorders, University of Florida, 1200 Newell Dr, Gainesville, FL 32610, USA
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Van Den Berge N, Ulusoy A. Animal models of brain-first and body-first Parkinson's disease. Neurobiol Dis 2022; 163:105599. [DOI: 10.1016/j.nbd.2021.105599] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 12/14/2021] [Accepted: 12/20/2021] [Indexed: 12/15/2022] Open
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12
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Cui W, Yang X, Chen X, Xiao D, Zhu J, Zhang M, Qin X, Ma X, Lin Y. Treating LRRK2‐Related Parkinson's Disease by Inhibiting the mTOR Signaling Pathway to Restore Autophagy. ADVANCED FUNCTIONAL MATERIALS 2021. [DOI: 10.1002/adfm.202105152] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Weitong Cui
- State Key Laboratory of Oral Diseases National Clinical Research Center for Oral Diseases West China Hospital of Stomatology Sichuan University Chengdu 610041 China
| | - Xiao Yang
- Psychiatric Laboratory and Mental Health Center West China Hospital of Sichuan University Chengdu 610041 China
| | - Xingyu Chen
- State Key Laboratory of Oral Diseases National Clinical Research Center for Oral Diseases West China Hospital of Stomatology Sichuan University Chengdu 610041 China
| | - Dexuan Xiao
- State Key Laboratory of Oral Diseases National Clinical Research Center for Oral Diseases West China Hospital of Stomatology Sichuan University Chengdu 610041 China
| | - Junyao Zhu
- State Key Laboratory of Oral Diseases National Clinical Research Center for Oral Diseases West China Hospital of Stomatology Sichuan University Chengdu 610041 China
| | - Mei Zhang
- State Key Laboratory of Oral Diseases National Clinical Research Center for Oral Diseases West China Hospital of Stomatology Sichuan University Chengdu 610041 China
| | - Xin Qin
- State Key Laboratory of Oral Diseases National Clinical Research Center for Oral Diseases West China Hospital of Stomatology Sichuan University Chengdu 610041 China
| | - Xiaohong Ma
- Psychiatric Laboratory and Mental Health Center West China Hospital of Sichuan University Chengdu 610041 China
| | - Yunfeng Lin
- State Key Laboratory of Oral Diseases National Clinical Research Center for Oral Diseases West China Hospital of Stomatology Sichuan University Chengdu 610041 China
- College of Biomedical Engineering Sichuan University Chengdu 610041 P. R. China
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Na + leak-current channel (NALCN) at the junction of motor and neuropsychiatric symptoms in Parkinson's disease. J Neural Transm (Vienna) 2021; 128:749-762. [PMID: 33961117 DOI: 10.1007/s00702-021-02348-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 04/30/2021] [Indexed: 12/27/2022]
Abstract
Parkinson's disease (PD) is a debilitating movement disorder often accompanied by neuropsychiatric symptoms that stem from the loss of dopaminergic function in the basal ganglia and altered neurotransmission more generally. Akinesia, postural instability, tremors and frozen gait constitute the major motor disturbances, whereas neuropsychiatric symptoms include altered circadian rhythms, disordered sleep, depression, psychosis and cognitive impairment. Evidence is emerging that the motor and neuropsychiatric symptoms may share etiologic factors. Calcium/ion channels (CACNA1C, NALCN), synaptic proteins (SYNJ1) and neuronal RNA-binding proteins (RBFOX1) are among the risk genes that are common to PD and various psychiatric disorders. The Na+ leak-current channel (NALCN) is the focus of this review because it has been implicated in dystonia, regulation of movement, cognitive impairment, sleep and circadian rhythms. It regulates the resting membrane potential in neurons, mediates pace-making activity, participates in synaptic vesicle recycling and is functionally co-localized to the endoplasmic reticulum (ER)-several of the major processes adversely affected in PD. Here, we summarize the literature on mechanisms and pathways that connect the motor and neuropsychiatric symptoms of PD with a focus on recurring relationships to the NALCN. It is hoped that the various connections outlined here will stimulate further discussion, suggest additional areas for exploration and ultimately inspire novel treatment strategies.
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