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Yang Y, Zhang Z. α-Synuclein pathology from the body to the brain: so many seeds so close to the central soil. Neural Regen Res 2024; 19:1463-1472. [PMID: 38051888 PMCID: PMC10883481 DOI: 10.4103/1673-5374.387967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 08/24/2023] [Indexed: 12/07/2023] Open
Abstract
ABSTRACT α-Synuclein is a protein that mainly exists in the presynaptic terminals. Abnormal folding and accumulation of α-synuclein are found in several neurodegenerative diseases, including Parkinson's disease. Aggregated and highly phosphorylated α-synuclein constitutes the main component of Lewy bodies in the brain, the pathological hallmark of Parkinson's disease. For decades, much attention has been focused on the accumulation of α-synuclein in the brain parenchyma rather than considering Parkinson's disease as a systemic disease. Recent evidence demonstrates that, at least in some patients, the initial α-synuclein pathology originates in the peripheral organs and spreads to the brain. Injection of α-synuclein preformed fibrils into the gastrointestinal tract triggers the gut-to-brain propagation of α-synuclein pathology. However, whether α-synuclein pathology can occur spontaneously in peripheral organs independent of exogenous α-synuclein preformed fibrils or pathological α-synuclein leakage from the central nervous system remains under investigation. In this review, we aimed to summarize the role of peripheral α-synuclein pathology in the pathogenesis of Parkinson's disease. We also discuss the pathways by which α-synuclein pathology spreads from the body to the brain.
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Affiliation(s)
- Yunying Yang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, Hubei Province, China
| | - Zhentao Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, Hubei Province, China
- TaiKang Center for Life and Medical Sciences, Wuhan University, Wuhan, Hubei Province, China
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2
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Zhang N, Yan Z, Xin H, Shao S, Xue S, Cespuglio R, Wang S. Relationship among α‑synuclein, aging and inflammation in Parkinson's disease (Review). Exp Ther Med 2024; 27:23. [PMID: 38125364 PMCID: PMC10728906 DOI: 10.3892/etm.2023.12311] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 10/19/2023] [Indexed: 12/23/2023] Open
Abstract
Parkinson's disease (PD) is a common neurodegenerative pathology whose major clinical symptoms are movement disorders. The main pathological characteristics of PD are the selective death of dopaminergic (DA) neurons in the pars compacta of the substantia nigra and the presence of Lewy bodies containing α-synuclein (α-Syn) within these neurons. PD is associated with numerous risk factors, including environmental factors, genetic mutations and aging. In many cases, the complex interplay of numerous risk factors leads to the onset of PD. The mutated α-Syn gene, which expresses pathologicalα-Syn protein, can cause PD. Another important feature of PD is neuroinflammation, which is conducive to neuronal death. α-Syn is able to interact with certain cell types in the brain, including through phagocytosis and degradation of α-Syn by glial cells, activation of inflammatory pathways by α-Syn in glial cells, transmission of α-Syn between glial cells and neurons, and interactions between peripheral immune cells and α-Syn. In addition to the aforementioned risk factors, PD may also be associated with aging, as the prevalence of PD increases with advancing age. The aging process impairs the cellular clearance mechanism, which leads to chronic inflammation and the accumulation of intracellular α-Syn, which results in DA neuronal death. In the present review, the age-associated α-Syn pathogenicity and the interactions between α-Syn and certain types of cells within the brain are discussed to facilitate understanding of the mechanisms of PD pathogenesis, which may potentially provide insight for the future clinical treatment of PD.
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Affiliation(s)
- Nianping Zhang
- Postdoctoral Mobile Station, Shandong University of Traditional Chinese Medicine, Jinan, Shandong 250355, P.R. China
- Experimental Center, Shandong University of Traditional Chinese Medicine, Jinan, Shandong 250355, P.R. China
| | - Zhaoli Yan
- Department of Neurosurgery, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, Shandong 250014, P.R. China
| | - Hua Xin
- Department of Neurology, People's Hospital of Rizhao, Rizhao, Shandong 276800, P.R. China
| | - Shuai Shao
- Department of Reproductive Medicine, Jingmen People's Hospital, Jingmen, Hubei 448000, P.R. China
| | - Song Xue
- Experimental Center, Shandong University of Traditional Chinese Medicine, Jinan, Shandong 250355, P.R. China
| | - Raymond Cespuglio
- Neuroscience Research Center of Lyon (CNRL), Claude-Bernard Lyon-1 University, 69500 Lyon, France
| | - Shijun Wang
- Department of Pathology, College of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, Shandong 250355, P.R. China
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3
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Saramowicz K, Siwecka N, Galita G, Kucharska-Lusina A, Rozpędek-Kamińska W, Majsterek I. Alpha-Synuclein Contribution to Neuronal and Glial Damage in Parkinson's Disease. Int J Mol Sci 2023; 25:360. [PMID: 38203531 PMCID: PMC10778752 DOI: 10.3390/ijms25010360] [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: 11/22/2023] [Revised: 12/18/2023] [Accepted: 12/21/2023] [Indexed: 01/12/2024] Open
Abstract
Parkinson's disease (PD) is a complex neurodegenerative disease characterized by the progressive loss of dopaminergic neurons in the substantia nigra and the widespread accumulation of alpha-synuclein (αSyn) protein aggregates. αSyn aggregation disrupts critical cellular processes, including synaptic function, mitochondrial integrity, and proteostasis, which culminate in neuronal cell death. Importantly, αSyn pathology extends beyond neurons-it also encompasses spreading throughout the neuronal environment and internalization by microglia and astrocytes. Once internalized, glia can act as neuroprotective scavengers, which limit the spread of αSyn. However, they can also become reactive, thereby contributing to neuroinflammation and the progression of PD. Recent advances in αSyn research have enabled the molecular diagnosis of PD and accelerated the development of targeted therapies. Nevertheless, despite more than two decades of research, the cellular function, aggregation mechanisms, and induction of cellular damage by αSyn remain incompletely understood. Unraveling the interplay between αSyn, neurons, and glia may provide insights into disease initiation and progression, which may bring us closer to exploring new effective therapeutic strategies. Herein, we provide an overview of recent studies emphasizing the multifaceted nature of αSyn and its impact on both neuron and glial cell damage.
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Affiliation(s)
| | | | | | | | | | - Ireneusz Majsterek
- Department of Clinical Chemistry and Biochemistry, Medical University of Lodz, 92-215 Lodz, Poland; (K.S.); (N.S.); (G.G.); (A.K.-L.); (W.R.-K.)
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4
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Zhang X, Tang B, Guo J. Parkinson's disease and gut microbiota: from clinical to mechanistic and therapeutic studies. Transl Neurodegener 2023; 12:59. [PMID: 38098067 PMCID: PMC10722742 DOI: 10.1186/s40035-023-00392-8] [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: 07/26/2023] [Accepted: 11/27/2023] [Indexed: 12/17/2023] Open
Abstract
Parkinson's disease (PD) is one of the most prevalent neurodegenerative diseases. The typical symptomatology of PD includes motor symptoms; however, a range of nonmotor symptoms, such as intestinal issues, usually occur before the motor symptoms. Various microorganisms inhabiting the gastrointestinal tract can profoundly influence the physiopathology of the central nervous system through neurological, endocrine, and immune system pathways involved in the microbiota-gut-brain axis. In addition, extensive evidence suggests that the gut microbiota is strongly associated with PD. This review summarizes the latest findings on microbial changes in PD and their clinical relevance, describes the underlying mechanisms through which intestinal bacteria may mediate PD, and discusses the correlations between gut microbes and anti-PD drugs. In addition, this review outlines the status of research on microbial therapies for PD and the future directions of PD-gut microbiota research.
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Affiliation(s)
- Xuxiang Zhang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, 410008, China
| | - Beisha Tang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, 410008, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, 410008, China
- Hunan International Scientific and Technological Cooperation Base of Neurodegenerative and Neurogenetic Diseases, Changsha, 410008, China
- Center for Medical Genetics and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, 410008, China
- Engineering Research Center of Hunan Province in Cognitive Impairment Disorders, Central South University, Changsha, 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, China
| | - Jifeng Guo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, 410008, China.
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, 410008, China.
- Hunan International Scientific and Technological Cooperation Base of Neurodegenerative and Neurogenetic Diseases, Changsha, 410008, China.
- Center for Medical Genetics and Hunan Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, 410008, China.
- Engineering Research Center of Hunan Province in Cognitive Impairment Disorders, Central South University, Changsha, 410008, China.
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, China.
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5
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Zhang Z, Liu Z, Lv A, Fan C. How Toll-like receptors influence Parkinson's disease in the microbiome-gut-brain axis. Front Immunol 2023; 14:1154626. [PMID: 37207228 PMCID: PMC10189046 DOI: 10.3389/fimmu.2023.1154626] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 04/17/2023] [Indexed: 05/21/2023] Open
Abstract
Recently, a large number of experimenters have found that the pathogenesis of Parkinson's disease may be related to the gut microbiome and proposed the microbiome-gut-brain axis. Studies have shown that Toll-like receptors, especially Toll-like receptor 2 (TLR2) and Toll-like receptor 4 (TLR4), are key mediators of gut homeostasis. In addition to their established role in innate immunity throughout the body, research is increasingly showing that the Toll-like receptor 2 and Toll-like receptor 4 signaling pathways shape the development and function of the gut and enteric nervous system. Notably, Toll-like receptor 2 and Toll-like receptor 4 are dysregulated in Parkinson's disease patients and may therefore be identified as the core of early gut dysfunction in Parkinson's disease. To better understand the contribution of Toll-like receptor 2 and Toll-like receptor 4 dysfunction in the gut to early α-synuclein aggregation, we discussed the structural function of Toll-like receptor 2 and Toll-like receptor 4 and signal transduction of Toll-like receptor 2 and Toll-like receptor 4 in Parkinson's disease by reviewing clinical, animal models, and in vitro studies. We also present a conceptual model of the pathogenesis of Parkinson's disease, in which microbial dysbiosis alters the gut barrier as well as the Toll-like receptor 2 and Toll-like receptor 4 signaling pathways, ultimately leading to a positive feedback loop for chronic gut dysfunction, promoting α-synuclein aggregation in the gut and vagus nerve.
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Affiliation(s)
- Ziyi Zhang
- Department of Anesthesiology, Baotou Central Hospital, Baotou, China
- Baotou Clinical Medical College, Inner Mongolia Medical University, Baotou, China
| | - Zhihui Liu
- Department of Anesthesiology, Baotou Central Hospital, Baotou, China
- *Correspondence: Zhihui Liu,
| | - Ao Lv
- The First Clinical College, Shanxi Medical University, Taiyuan, Shanxi, China
| | - Chenhui Fan
- Safety Engineering, People’s Public Security University of China, Beijing, China
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6
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An opinion on the debatable function of brain resident immune protein, T-cell receptor beta subunit in the central nervous system. IBRO Neurosci Rep 2022; 13:235-242. [PMID: 36590097 PMCID: PMC9795316 DOI: 10.1016/j.ibneur.2022.09.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 09/02/2022] [Indexed: 01/04/2023] Open
Abstract
In recent years scientific research has established that the nervous and immune systems have shared molecular signaling components. Proteins native to immune cells, which are also found in the brain, have neuronal functions in the nervous system where they affect synaptic plasticity, axonal regeneration, neurogenesis, and neurotransmission. Certain native immune molecules like major histocompatibility complex I (MHC-I), paired immunoglobulin receptor B (PirB), toll-like receptor (TLR), cluster of differentiation-3 zeta (CD3ζ), CD4 co-receptor, and T-cell receptor beta (TCR-β) expression in neurons have been extensively documented. In this review, we provide our opinion and discussed the possible roles of T-cell receptor beta subunits in modulating the function of neurons in the central nervous system. Based on the previous findings of Syken and Shatz., 2003; Nishiyori et al., 2004; Rodriguez et., 1993 and Komal et., 2014; we discuss whether restrictive expression of TCR-β subunits in selected brain regions could be involved in the pathology of neurological disorders and whether their aberrant enhancement in expression may be considered as a suitable biomarker for aging or neurodegenerative diseases like Huntington's disease (HD).
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7
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Fields JA, Swinton M, Sundermann EE, Scrivens N, Vallee KAJ, Moore DJ. Complement component 3 and complement factor H protein levels are altered in brain tissues from people with human immunodeficiency virus: A pilot study. Front Aging Neurosci 2022; 14:981937. [PMID: 36118688 PMCID: PMC9472593 DOI: 10.3389/fnagi.2022.981937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 08/01/2022] [Indexed: 11/13/2022] Open
Abstract
People with HIV (PWH) continue to suffer from dysfunction of the central nervous system, as evidenced by HIV-associated neurocognitive disorder (HAND), despite antiretroviral therapy and suppressed viral loads. As PWH live longer they may also be at risk of age-related neurodegenerative diseases such Alzheimer’s disease (AD) and its precursor, amnestic mild cognitive impairment (aMCI). The complement system is associated with deposition of AD-related proteins such as beta amyloid (Aβ), neuroinflammation, and neurological dysfunction in PWH. Complement component 3 (C3) is a key protagonist in the complement cascade and complement factor H (CFH) is an antagonist of C3 activity. We investigated the relationship between C3 and CFH levels in the brain and Aβ plaques and neurological dysfunction in 22 PWH. We analyzed by immunoblot C3 and CFH protein levels in frontal cortex (FC) and cerebellum (CB) brain specimens from PWH previously characterized for Aβ plaque deposition. C3 and CFH protein levels were then correlated with specific cognitive domains. C3 protein levels in the FC were significantly increased in brains with Aβ plaques and in brains with HAND compared to controls. In the CB, C3 levels trended higher in brains with Aβ plaques. Overall C3 protein levels were significantly higher in the FC compared to the CB, but the opposite was true for CFH, having significantly higher levels of CFH protein in the CB compared to the FC. However, only CFH in the FC showed significant correlations with specific domains, executive function and motor performance. These findings corroborate previous results showing that complement system proteins are associated with HAND and AD neuropathogenesis.
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8
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Ruf WP, Meirelles J, Danzer KM. Spreading of alpha-synuclein between different cell types. Behav Brain Res 2022; 436:114059. [PMID: 35995264 DOI: 10.1016/j.bbr.2022.114059] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 08/07/2022] [Accepted: 08/10/2022] [Indexed: 10/15/2022]
Abstract
Aggregation of alpha-synuclein (α-syn) is central in Parkinson's disease as well as in other synucleinopathies. Recent evidence suggests that not only intracellular aggregation of α-syn plays an important role for disease pathogenesis but also cell-to-cell propagation of α-syn seems to significantly contribute to pathological changes in synucleinopathies. In this mini-review we summarize current aspects of spreading of α-syn between brain cell types and its role in pathology.
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Affiliation(s)
- Wolfgang P Ruf
- Department of Neurology, University Clinic, University of Ulm, Ulm, Germany
| | - Joao Meirelles
- German Center for Neurodegenerative Diseases (DZNE), Ulm, Germany
| | - Karin M Danzer
- Department of Neurology, University Clinic, University of Ulm, Ulm, Germany; German Center for Neurodegenerative Diseases (DZNE), Ulm, Germany.
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9
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Microglia Phenotypes in Aging and Neurodegenerative Diseases. Cells 2022; 11:cells11132091. [PMID: 35805174 PMCID: PMC9266143 DOI: 10.3390/cells11132091] [Citation(s) in RCA: 80] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 06/24/2022] [Accepted: 06/29/2022] [Indexed: 02/08/2023] Open
Abstract
Neuroinflammation is a hallmark of many neurodegenerative diseases (NDs) and plays a fundamental role in mediating the onset and progression of disease. Microglia, which function as first-line immune guardians of the central nervous system (CNS), are the central drivers of neuroinflammation. Numerous human postmortem studies and in vivo imaging analyses have shown chronically activated microglia in patients with various acute and chronic neuropathological diseases. While microglial activation is a common feature of many NDs, the exact role of microglia in various pathological states is complex and often contradictory. However, there is a consensus that microglia play a biphasic role in pathological conditions, with detrimental and protective phenotypes, and the overall response of microglia and the activation of different phenotypes depends on the nature and duration of the inflammatory insult, as well as the stage of disease development. This review provides a comprehensive overview of current research on the various microglia phenotypes and inflammatory responses in health, aging, and NDs, with a special emphasis on the heterogeneous phenotypic response of microglia in acute and chronic diseases such as hemorrhagic stroke (HS), Alzheimer’s disease (AD), and Parkinson’s disease (PD). The primary focus is translational research in preclinical animal models and bulk/single-cell transcriptome studies in human postmortem samples. Additionally, this review covers key microglial receptors and signaling pathways that are potential therapeutic targets to regulate microglial inflammatory responses during aging and in NDs. Additionally, age-, sex-, and species-specific microglial differences will be briefly reviewed.
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10
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Vidović M, Rikalovic MG. Alpha-Synuclein Aggregation Pathway in Parkinson's Disease: Current Status and Novel Therapeutic Approaches. Cells 2022; 11:cells11111732. [PMID: 35681426 PMCID: PMC9179656 DOI: 10.3390/cells11111732] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 05/20/2022] [Accepted: 05/22/2022] [Indexed: 01/27/2023] Open
Abstract
Following Alzheimer’s, Parkinson’s disease (PD) is the second-most common neurodegenerative disorder, sharing an unclear pathophysiology, a multifactorial profile, and massive social costs worldwide. Despite this, no disease-modifying therapy is available. PD is tightly associated with α-synuclein (α-Syn) deposits, which become organised into insoluble, amyloid fibrils. As a typical intrinsically disordered protein, α-Syn adopts a monomeric, random coil conformation in an aqueous solution, while its interaction with lipid membranes drives the transition of the molecule part into an α-helical structure. The central unstructured region of α-Syn is involved in fibril formation by converting to well-defined, β-sheet rich secondary structures. Presently, most therapeutic strategies against PD are focused on designing small molecules, peptides, and peptidomimetics that can directly target α-Syn and its aggregation pathway. Other approaches include gene silencing, cell transplantation, stimulation of intracellular clearance with autophagy promoters, and degradation pathways based on immunotherapy of amyloid fibrils. In the present review, we sum marise the current advances related to α-Syn aggregation/neurotoxicity. These findings present a valuable arsenal for the further development of efficient, nontoxic, and non-invasive therapeutic protocols for disease-modifying therapy that tackles disease onset and progression in the future.
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Affiliation(s)
- Marija Vidović
- Laboratory for Plant Molecular Biology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444a, 11042 Belgrade, Serbia
- Correspondence: ; Tel.: +38-16-4276-3221
| | - Milena G. Rikalovic
- Environment and Sustainable Development, Singidunum Univeristy, Danijelova 32, 11010 Belgrade, Serbia;
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Chavarría C, Ivagnes R, Souza JM. Extracellular Alpha-Synuclein: Mechanisms for Glial Cell Internalization and Activation. Biomolecules 2022; 12:biom12050655. [PMID: 35625583 PMCID: PMC9138387 DOI: 10.3390/biom12050655] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 04/22/2022] [Accepted: 04/27/2022] [Indexed: 11/16/2022] Open
Abstract
Alpha-synuclein (α-syn) is a small protein composed of 140 amino acids and belongs to the group of intrinsically disordered proteins. It is a soluble protein that is highly expressed in neurons and expressed at low levels in glial cells. The monomeric protein aggregation process induces the formation of oligomeric intermediates and proceeds towards fibrillar species. These α-syn conformational species have been detected in the extracellular space and mediate consequences on surrounding neurons and glial cells. In particular, higher-ordered α-syn aggregates are involved in microglial and oligodendrocyte activation, as well as in the induction of astrogliosis. These phenomena lead to mitochondrial dysfunction, reactive oxygen and nitrogen species formation, and the induction of an inflammatory response, associated with neuronal cell death. Several receptors participate in cell activation and/or in the uptake of α-syn, which can vary depending on the α-syn aggregated state and cell types. The receptors involved in this process are of outstanding relevance because they may constitute potential therapeutic targets for the treatment of PD and related synucleinopathies. This review article focuses on the mechanism associated with extracellular α-syn uptake in glial cells and the consequent glial cell activation that contributes to the neuronal death associated with synucleinopathies.
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12
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Szabo MP, Iba M, Nath A, Masliah E, Kim C. Does SARS-CoV-2 affect neurodegenerative disorders? TLR2, a potential receptor for SARS-CoV-2 in the CNS. Exp Mol Med 2022; 54:447-454. [PMID: 35396576 PMCID: PMC8990637 DOI: 10.1038/s12276-022-00755-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 01/13/2022] [Indexed: 12/15/2022] Open
Abstract
The coronavirus (COVID-19) pandemic, caused by severe acute respiratory system coronavirus 2 (SARS-CoV-2), has created significant challenges for scientists seeking to understand the pathogenic mechanisms of SARS-CoV-2 infection and to identify the best therapies for infected patients. Although ACE2 is a known receptor for the virus and has been shown to mediate viral entry into the lungs, accumulating reports highlight the presence of neurological symptoms resulting from infection. As ACE2 expression is low in the central nervous system (CNS), these neurological symptoms are unlikely to be caused by ACE2-virus binding. In this review, we will discuss a proposed interaction between SARS-CoV-2 and Toll-like receptor 2 (TLR2) in the CNS. TLR2 is an innate immune receptor that recognizes exogenous microbial components but has also been shown to interact with multiple viral components, including the envelope (E) protein of SARS-CoV-2. In addition, TLR2 plays an important role in the pathogenesis of neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD). Based on these observations, we hypothesize that TLR2 may play a critical role in the response to SARS-CoV-2 infiltration in the CNS, thereby resulting in the induction or acceleration of AD and PD pathologies in patients.
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Affiliation(s)
- Marcell P Szabo
- Molecular Neuropathology Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Michiyo Iba
- Molecular Neuropathology Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Avindra Nath
- Section of Infections of the Nervous System, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Eliezer Masliah
- Molecular Neuropathology Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA. .,Division of Neuroscience, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Changyoun Kim
- Molecular Neuropathology Section, Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, 20892, USA.
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13
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NPT1220-312, a TLR2/TLR9 Small Molecule Antagonist, Inhibits Pro-Inflammatory Signaling, Cytokine Release, and NLRP3 Inflammasome Activation. Int J Inflam 2022; 2022:2337363. [PMID: 35265316 PMCID: PMC8898874 DOI: 10.1155/2022/2337363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 01/12/2022] [Accepted: 01/30/2022] [Indexed: 11/24/2022] Open
Abstract
Toll-like receptors (TLRs) play a critical role in innate immune system responses to damage-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs). A growing body of evidence suggests that excessive TLR-mediated innate immune system activation can lead to neuronal damage and precipitate or perpetuate neurodegenerative diseases. Among TLR subtypes, both TLR2 and TLR9 have been implicated in neurodegenerative disorders with increased expression of these receptors in the central nervous system being associated with pro-inflammatory signaling and increased burdens of pathologic aggregated proteins. In the current study, we characterized the actions of a combined TLR2/TLR9 antagonist, NPT1220-312, on pro-inflammatory signaling and cytokine release in monocyte/macrophage-derived heterologous cells, human microglia, and murine and human whole blood. NPT1220-312 potently blocked TLR2- and TLR9-mediated release of inflammatory cytokines in monocyte/macrophage cells and in human microglia. NPT1220-312 also blocked TLR2-mediated activation of the NLR family pyrin domain containing 3 (NLRP3) inflammasome including IL-1β, IL-18, and apoptosis-associated speck-like protein containing a CARD (ASC) release to the culture medium of human differentiated macrophages. The ability of NPT1220-312 to inhibit TLR2 mediated pro-inflammatory release of chemokines and cytokines in situ was demonstrated using murine and human whole blood. Together, these findings suggest that blockade of TLR2 and TLR9 may reduce inappropriate production of pro-inflammatory cytokines and chemokines from peripheral and central immune cells and thus potentially provide therapeutic benefit in neuroinflammatory/neurodegenerative disorders.
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14
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Weiss F, Labrador-Garrido A, Dzamko N, Halliday G. Immune responses in the Parkrtdinson's disease brain. Neurobiol Dis 2022; 168:105700. [DOI: 10.1016/j.nbd.2022.105700] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 03/14/2022] [Accepted: 03/15/2022] [Indexed: 12/15/2022] Open
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15
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Lai TT, Kim YJ, Ma HI, Kim YE. Evidence of Inflammation in Parkinson’s Disease and Its Contribution to Synucleinopathy. J Mov Disord 2022; 15:1-14. [PMID: 35124957 PMCID: PMC8820875 DOI: 10.14802/jmd.21078] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Accepted: 08/04/2021] [Indexed: 12/15/2022] Open
Abstract
Accumulation of alpha-synuclein (αSyn) protein in neurons is a renowned pathological hallmark of Parkinson’s disease (PD). In addition, accumulating evidence indicates that activated inflammatory responses are involved in the pathogenesis of PD. Thus, achieving a better understanding of the interaction between inflammation and synucleinopathy in relation to the PD process will facilitate the development of promising disease-modifying therapies. In this review, the evidence of inflammation in PD is discussed, and human, animal, and laboratory studies relevant to the relationship between inflammation and αSyn are explored as well as new therapeutic targets associated with this relationship.
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Affiliation(s)
- Thuy Thi Lai
- Department of Neurology, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang, Korea
- Hallym Neurological Institute, Hallym University College of Medicine, Anyang, Korea
| | - Yun Joong Kim
- Department of Neurology, Yongin Severance Hospital, Yonsei University College of Medicine, Yongin, Korea
| | - Hyeo-il Ma
- Department of Neurology, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang, Korea
- Hallym Neurological Institute, Hallym University College of Medicine, Anyang, Korea
| | - Young Eun Kim
- Department of Neurology, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, Anyang, Korea
- Hallym Neurological Institute, Hallym University College of Medicine, Anyang, Korea
- Corresponding author: Young Eun Kim, MD Department of Neurology, Hallym University Sacred Heart Hospital, Hallym University College of Medicine, 22 Gwanpyeong-ro 170beon-gil, Dongangu, Anyang 14068, Korea / Tel: +82-31-380-3740 / E-mail:
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16
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Gorecki AM, Anyaegbu CC, Anderton RS. TLR2 and TLR4 in Parkinson's disease pathogenesis: the environment takes a toll on the gut. Transl Neurodegener 2021; 10:47. [PMID: 34814947 PMCID: PMC8609261 DOI: 10.1186/s40035-021-00271-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 10/29/2021] [Indexed: 02/08/2023] Open
Abstract
Parkinson's disease (PD) is an incurable, devastating disorder that is characterized by pathological protein aggregation and neurodegeneration in the substantia nigra. In recent years, growing evidence has implicated the gut environment and the gut-brain axis in the pathogenesis and progression of PD, especially in a subset of people who exhibit prodromal gastrointestinal dysfunction. Specifically, perturbations of gut homeostasis are hypothesized to contribute to α-synuclein aggregation in enteric neurons, which may spread to the brain over decades and eventually result in the characteristic central nervous system manifestations of PD, including neurodegeneration and motor impairments. However, the mechanisms linking gut disturbances and α-synuclein aggregation are still unclear. A plethora of research indicates that toll-like receptors (TLRs), especially TLR2 and TLR4, are critical mediators of gut homeostasis. Alongside their established role in innate immunity throughout the body, studies are increasingly demonstrating that TLR2 and TLR4 signalling shapes the development and function of the gut and the enteric nervous system. Notably, TLR2 and TLR4 are dysregulated in patients with PD, and may thus be central to early gut dysfunction in PD. To better understand the putative contribution of intestinal TLR2 and TLR4 dysfunction to early α-synuclein aggregation and PD, we critically discuss the role of TLR2 and TLR4 in normal gut function as well as evidence for altered TLR2 and TLR4 signalling in PD, by reviewing clinical, animal model and in vitro research. Growing evidence on the immunological aetiology of α-synuclein aggregation is also discussed, with a focus on the interactions of α-synuclein with TLR2 and TLR4. We propose a conceptual model of PD pathogenesis in which microbial dysbiosis alters the permeability of the intestinal barrier as well as TLR2 and TLR4 signalling, ultimately leading to a positive feedback loop of chronic gut dysfunction promoting α-synuclein aggregation in enteric and vagal neurons. In turn, α-synuclein aggregates may then migrate to the brain via peripheral nerves, such as the vagal nerve, to contribute to neuroinflammation and neurodegeneration typically associated with PD.
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Affiliation(s)
- Anastazja M Gorecki
- School of Biological Science, University of Western Australia, Crawley, WA, Australia.
- Neurodegenerative Disorders Research Group, Perron Institute for Neurological and Translational Science, Nedlands, WA, Australia.
| | - Chidozie C Anyaegbu
- Curtin Health Innovation Research Institute, Ralph and Patricia Sarich Neuroscience Research Institute, Curtin University, Nedlands, WA, Australia
| | - Ryan S Anderton
- Faculty of Medicine, Nursing and Midwifery and Faculty of Health Sciences, University of Notre Dame Australia, Fremantle, WA, Australia
- School of Nursing, Midwifery, Health Sciences and Physiotherapy, University of Notre Dame Australia, Fremantle, WA, Australia
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Wang C, Yang T, Liang M, Xie J, Song N. Astrocyte dysfunction in Parkinson's disease: from the perspectives of transmitted α-synuclein and genetic modulation. Transl Neurodegener 2021; 10:39. [PMID: 34657636 PMCID: PMC8522040 DOI: 10.1186/s40035-021-00265-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 10/05/2021] [Indexed: 01/20/2023] Open
Abstract
Parkinson's disease (PD) is a common neurodegenerative disorder that primarily affects the elderly. While the etiology of PD is likely multifactorial with the involvement of genetic, environmental, aging and other factors, α-synuclein (α-syn) pathology is a pivotal mechanism underlying the development of PD. In recent years, astrocytes have attracted considerable attention in the field. Although astrocytes perform a variety of physiological functions in the brain, they are pivotal mediators of α-syn toxicity since they internalize α-syn released from damaged neurons, and this triggers an inflammatory response, protein degradation dysfunction, mitochondrial dysfunction and endoplasmic reticulum stress. Astrocytes are indispensable coordinators in the background of several genetic mutations, including PARK7, GBA1, LRRK2, ATP13A2, PINK1, PRKN and PLA2G6. As the most abundant glial cells in the brain, functional astrocytes can be replenished and even converted to functional neurons. In this review, we discuss astrocyte dysfunction in PD with an emphasis on α-syn toxicity and genetic modulation and conclude that astrocyte replenishment is a valuable therapeutic approach in PD.
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Affiliation(s)
- Changjing Wang
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, School of Basic Medicine, Qingdao University, Qingdao, 266071, China
| | - Tongtong Yang
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, School of Basic Medicine, Qingdao University, Qingdao, 266071, China
| | - Meiyu Liang
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, School of Basic Medicine, Qingdao University, Qingdao, 266071, China
| | - Junxia Xie
- Institute of Brain Science and Disease, Qingdao University, Qingdao, 266071, China.
| | - Ning Song
- Department of Physiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, School of Basic Medicine, Qingdao University, Qingdao, 266071, China.
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18
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Kawahata I. [The novel mechanism of α-synuclein propagation in synucleinopathy]. Nihon Yakurigaku Zasshi 2021; 156:251. [PMID: 34193707 DOI: 10.1254/fpj.21033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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19
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Nazish I, Arber C, Piers TM, Warner TT, Hardy JA, Lewis PA, Pocock JM, Bandopadhyay R. Abrogation of LRRK2 dependent Rab10 phosphorylation with TLR4 activation and alterations in evoked cytokine release in immune cells. Neurochem Int 2021; 147:105070. [PMID: 34004238 PMCID: PMC7610942 DOI: 10.1016/j.neuint.2021.105070] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 05/11/2021] [Indexed: 02/08/2023]
Abstract
LRRK2 protein is expressed prominently in immune cells, cell types whose contribution to LRRK2-associated genetic Parkinson's disease (PD) is increasingly being recognised. We investigated the effect of inflammatory stimuli using RAW264.7 murine macrophage cells as model systems. A detailed time course of TLR2 and TLR4 stimulation was investigated through measuring LRRK2 phosphorylation at its specific phospho-sites, and Rab8 and Rab10 phosphorylation together with cytokine release following treatment with LPS and zymosan. LRRK2 phosphorylation at Ser935, Ser955 and Ser973 was increased significantly over untreated conditions at 4-24h in both WT-LRRK2 and T1348N-LRRK2 cell lines to similar extents although levels of Ser910 phosphorylation were maintained at higher levels throughout. Importantly we demonstrate that LPS stimulation significantly decreased phospho-Rab10 but not phospho-Rab8 levels over 4-24h in both WT-LRRK2 and T1348N-LRRK2 cell lines. The dephosphorylation of Rab10 was not attributed to its specific phosphatase, PPM1H as the levels remained unaltered with LPS treatment. MAPK phosphorylation occurred prior to LRRK2 phosphorylation which was validated by blocking TLR4 and TLR2 receptors with TAK242 or Sparstolonin B respectively. A significant decrease in basal level of TNFα release was noted in both T1348N-LRRK2 and KO-LRRK2 cell lines at 48h compared to WT-LRRK2 cell line, however LPS and zymosan treatment did not cause any significant alteration in the TNFα and IL-6 release between the three cell lines. In contrast, LPS and zymosan caused significantly lower IL-10 release in T1348N-LRRK2 and KO-LRRK2 cell lines. A significant decrease in phospho-Rab10 levels was also confirmed in human IPS-derived macrophages with TLR4 activation. Our data demonstrates for the first time that LRRK2-dependent Rab10 phosphorylation is modulated by LPS stimulation, and that cytokine release may be influenced by the status of LRRK2. These data provide further insights into the function of LRRK2 in immune response, and has relevance for understanding cellular dysfunctions when developing LRRK2-based inhibitors for clinical treatment.
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Affiliation(s)
- Iqra Nazish
- Reta Lila Weston Institute and Department of Clinical and Movement Neuroscience, UCL Queen Square Institute of Neurology, 1 Wakefield Street, WC1N 1PJ, UK
| | - Charles Arber
- Department of Neurodegenerative Diseases, UCL Queen Square Institute of Neurology, 1 Wakefield Street, WC1N 1PJ, UK
| | - Thomas M. Piers
- Department of Neuroinflammation, UCL Queen Square Institute of Neurology, 1 Wakefield Street, WC1N 1PJ, UK
| | - Thomas T. Warner
- Reta Lila Weston Institute and Department of Clinical and Movement Neuroscience, UCL Queen Square Institute of Neurology, 1 Wakefield Street, WC1N 1PJ, UK
| | - John A. Hardy
- Reta Lila Weston Institute and Department of Clinical and Movement Neuroscience, UCL Queen Square Institute of Neurology, 1 Wakefield Street, WC1N 1PJ, UK,Department of Neurodegenerative Diseases, UCL Queen Square Institute of Neurology, 1 Wakefield Street, WC1N 1PJ, UK,Queen Square Genomics, UCL Dementia Research Institute, Wing 1.2 Cruciform Building, Gower Street, London, WC1E 6BT, UK
| | - Patrick A. Lewis
- Department of Neurodegenerative Diseases, UCL Queen Square Institute of Neurology, 1 Wakefield Street, WC1N 1PJ, UK,Royal Veterinary College, Royal College Street, London, NW1 0TU, UK
| | - Jennifer M. Pocock
- Department of Neuroinflammation, UCL Queen Square Institute of Neurology, 1 Wakefield Street, WC1N 1PJ, UK
| | - Rina Bandopadhyay
- Reta Lila Weston Institute and Department of Clinical and Movement Neuroscience, UCL Queen Square Institute of Neurology, 1 Wakefield Street, WC1N 1PJ, UK.
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