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Ng XY, Cao M. Dysfunction of synaptic endocytic trafficking in Parkinson's disease. Neural Regen Res 2024; 19:2649-2660. [PMID: 38595283 PMCID: PMC11168511 DOI: 10.4103/nrr.nrr-d-23-01624] [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: 09/27/2023] [Revised: 12/12/2023] [Accepted: 01/03/2024] [Indexed: 04/11/2024] Open
Abstract
Parkinson's disease is characterized by the selective degeneration of dopamine neurons in the nigrostriatal pathway and dopamine deficiency in the striatum. The precise reasons behind the specific degeneration of these dopamine neurons remain largely elusive. Genetic investigations have identified over 20 causative PARK genes and 90 genomic risk loci associated with both familial and sporadic Parkinson's disease. Notably, several of these genes are linked to the synaptic vesicle recycling process, particularly the clathrin-mediated endocytosis pathway. This suggests that impaired synaptic vesicle recycling might represent an early feature of Parkinson's disease, followed by axonal degeneration and the eventual loss of dopamine cell bodies in the midbrain via a "dying back" mechanism. Recently, several new animal and cellular models with Parkinson's disease-linked mutations affecting the endocytic pathway have been created and extensively characterized. These models faithfully recapitulate certain Parkinson's disease-like features at the animal, circuit, and cellular levels, and exhibit defects in synaptic membrane trafficking, further supporting the findings from human genetics and clinical studies. In this review, we will first summarize the cellular and molecular findings from the models of two Parkinson's disease-linked clathrin uncoating proteins: auxilin (DNAJC6/PARK19) and synaptojanin 1 (SYNJ1/PARK20). The mouse models carrying these two PARK gene mutations phenocopy each other with specific dopamine terminal pathology and display a potent synergistic effect. Subsequently, we will delve into the involvement of several clathrin-mediated endocytosis-related proteins (GAK, endophilin A1, SAC2/INPP5F, synaptotagmin-11), identified as Parkinson's disease risk factors through genome-wide association studies, in Parkinson's disease pathogenesis. We will also explore the direct or indirect roles of some common Parkinson's disease-linked proteins (alpha-synuclein (PARK1/4), Parkin (PARK2), and LRRK2 (PARK8)) in synaptic endocytic trafficking. Additionally, we will discuss the emerging novel functions of these endocytic proteins in downstream membrane traffic pathways, particularly autophagy. Given that synaptic dysfunction is considered as an early event in Parkinson's disease, a deeper understanding of the cellular mechanisms underlying synaptic vesicle endocytic trafficking may unveil novel targets for early diagnosis and the development of interventional therapies for Parkinson's disease. Future research should aim to elucidate why generalized synaptic endocytic dysfunction leads to the selective degeneration of nigrostriatal dopamine neurons in Parkinson's disease.
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Affiliation(s)
- Xin Yi Ng
- Programme in Neuroscience and Behavioural Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Mian Cao
- Programme in Neuroscience and Behavioural Disorders, Duke-NUS Medical School, Singapore, Singapore
- Department of Physiology, National University of Singapore, Singapore, Singapore
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2
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Panagiotou S, Tan KW, Nguyen PM, Müller A, Oqua AI, Tomas A, Wendt A, Eliasson L, Tengholm A, Solimena M, Idevall-Hagren O. OSBP-mediated PI(4)P-cholesterol exchange at endoplasmic reticulum-secretory granule contact sites controls insulin secretion. Cell Rep 2024; 43:113992. [PMID: 38536815 DOI: 10.1016/j.celrep.2024.113992] [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: 10/04/2023] [Revised: 02/07/2024] [Accepted: 03/07/2024] [Indexed: 04/28/2024] Open
Abstract
Insulin is packaged into secretory granules that depart the Golgi and undergo a maturation process that involves changes in the protein and lipid composition of the granules. Here, we show that insulin secretory granules form physical contacts with the endoplasmic reticulum and that the lipid exchange protein oxysterol-binding protein (OSBP) is recruited to these sites in a Ca2+-dependent manner. OSBP binding to insulin granules is positively regulated by phosphatidylinositol-4 (PI4)-kinases and negatively regulated by the PI4 phosphate (PI(4)P) phosphatase Sac2. Loss of Sac2 results in excess accumulation of cholesterol on insulin granules that is normalized when OSBP expression is reduced, and both acute inhibition and small interfering RNA (siRNA)-mediated knockdown of OSBP suppress glucose-stimulated insulin secretion without affecting insulin production or intracellular Ca2+ signaling. In conclusion, we show that lipid exchange at endoplasmic reticulum (ER)-granule contact sites is involved in the exocytic process and propose that these contacts act as reaction centers with multimodal functions during insulin granule maturation.
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Affiliation(s)
| | - Kia Wee Tan
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Phuoc My Nguyen
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Andreas Müller
- Molecular Diabetology, University Hospital and Faculty of Medicine Carl Gustav Carus, TU Dresden, Dresden, Germany; Paul Langerhans Institute Dresden (PLID) of the Helmholtz Center Munich at the University Hospital Carl Gustav Carus and Faculty of Medicine of the TU Dresden, Dresden, Germany; German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
| | - Affiong Ika Oqua
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Alejandra Tomas
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Anna Wendt
- Department of Clinical Sciences, Lund University, Lund, Sweden; Lund University Diabetes Center (LUDC), Lund, Sweden
| | - Lena Eliasson
- Department of Clinical Sciences, Lund University, Lund, Sweden; Lund University Diabetes Center (LUDC), Lund, Sweden
| | - Anders Tengholm
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Michele Solimena
- Paul Langerhans Institute Dresden (PLID) of the Helmholtz Center Munich at the University Hospital Carl Gustav Carus and Faculty of Medicine of the TU Dresden, Dresden, Germany; German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany; Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
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Firdaus Z, Li X. Unraveling the Genetic Landscape of Neurological Disorders: Insights into Pathogenesis, Techniques for Variant Identification, and Therapeutic Approaches. Int J Mol Sci 2024; 25:2320. [PMID: 38396996 PMCID: PMC10889342 DOI: 10.3390/ijms25042320] [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: 01/18/2024] [Revised: 02/09/2024] [Accepted: 02/13/2024] [Indexed: 02/25/2024] Open
Abstract
Genetic abnormalities play a crucial role in the development of neurodegenerative disorders (NDDs). Genetic exploration has indeed contributed to unraveling the molecular complexities responsible for the etiology and progression of various NDDs. The intricate nature of rare and common variants in NDDs contributes to a limited understanding of the genetic risk factors associated with them. Advancements in next-generation sequencing have made whole-genome sequencing and whole-exome sequencing possible, allowing the identification of rare variants with substantial effects, and improving the understanding of both Mendelian and complex neurological conditions. The resurgence of gene therapy holds the promise of targeting the etiology of diseases and ensuring a sustained correction. This approach is particularly enticing for neurodegenerative diseases, where traditional pharmacological methods have fallen short. In the context of our exploration of the genetic epidemiology of the three most prevalent NDDs-amyotrophic lateral sclerosis, Alzheimer's disease, and Parkinson's disease, our primary goal is to underscore the progress made in the development of next-generation sequencing. This progress aims to enhance our understanding of the disease mechanisms and explore gene-based therapies for NDDs. Throughout this review, we focus on genetic variations, methodologies for their identification, the associated pathophysiology, and the promising potential of gene therapy. Ultimately, our objective is to provide a comprehensive and forward-looking perspective on the emerging research arena of NDDs.
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Affiliation(s)
- Zeba Firdaus
- Department of Internal Medicine, Mayo Clinic, Rochester, MN 55905, USA;
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
| | - Xiaogang Li
- Department of Internal Medicine, Mayo Clinic, Rochester, MN 55905, USA;
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN 55905, USA
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4
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Gupta S, Khan J, Ghosh S. Molecular mechanism of cognitive impairment associated with Parkinson's disease: A stroke perspective. Life Sci 2024; 337:122358. [PMID: 38128756 DOI: 10.1016/j.lfs.2023.122358] [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: 06/20/2023] [Revised: 12/03/2023] [Accepted: 12/13/2023] [Indexed: 12/23/2023]
Abstract
Parkinson's disease (PD) is a common neurological illness that causes several motor and non-motor symptoms, most characteristically limb tremors and bradykinesia. PD is a slowly worsening disease that arises due to progressive neurodegeneration of specific areas of the brain, especially the substantia nigra of the midbrain. Even though PD has continuously been linked to a higher mortality risk in numerous epidemiologic studies, there have been significant discoveries regarding the connection between PD and stroke. The incidence of strokes such as cerebral infarction and hemorrhage is substantially associated with the development of PD. Moreover, cognitive impairments, primarily dementia, have been associated with stroke and PD. However, the underlying molecular mechanism of this phenomenon is still obscure. This concise review focuses on the relationship between stroke and PD, emphasizing the molecular mechanism of cognition deficit and memory loss evident in PD and stroke. Furthermore, we are also highlighting some potential drug molecules that can target both PD and stroke.
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Affiliation(s)
- Sanju Gupta
- Department of Bioscience & Bioengineering, Indian Institute of Technology Jodhpur (IIT-Jodhpur), Rajasthan 342037, India
| | - Juhee Khan
- Department of Bioscience & Bioengineering, Indian Institute of Technology Jodhpur (IIT-Jodhpur), Rajasthan 342037, India
| | - Surajit Ghosh
- Department of Bioscience & Bioengineering, Indian Institute of Technology Jodhpur (IIT-Jodhpur), Rajasthan 342037, India.
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5
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Sigrist SJ, Haucke V. Orchestrating vesicular and nonvesicular membrane dynamics by intrinsically disordered proteins. EMBO Rep 2023; 24:e57758. [PMID: 37680133 PMCID: PMC10626433 DOI: 10.15252/embr.202357758] [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: 07/05/2023] [Revised: 08/22/2023] [Accepted: 08/24/2023] [Indexed: 09/09/2023] Open
Abstract
Compartmentalization by membranes is a common feature of eukaryotic cells and serves to spatiotemporally confine biochemical reactions to control physiology. Membrane-bound organelles such as the endoplasmic reticulum (ER), the Golgi complex, endosomes and lysosomes, and the plasma membrane, continuously exchange material via vesicular carriers. In addition to vesicular trafficking entailing budding, fission, and fusion processes, organelles can form membrane contact sites (MCSs) that enable the nonvesicular exchange of lipids, ions, and metabolites, or the secretion of neurotransmitters via subsequent membrane fusion. Recent data suggest that biomolecule and information transfer via vesicular carriers and via MCSs share common organizational principles and are often mediated by proteins with intrinsically disordered regions (IDRs). Intrinsically disordered proteins (IDPs) can assemble via low-affinity, multivalent interactions to facilitate membrane tethering, deformation, fission, or fusion. Here, we review our current understanding of how IDPs drive the formation of multivalent protein assemblies and protein condensates to orchestrate vesicular and nonvesicular transport with a special focus on presynaptic neurotransmission. We further discuss how dysfunction of IDPs causes disease and outline perspectives for future research.
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Affiliation(s)
- Stephan J Sigrist
- Department of Biology, Chemistry, PharmacyFreie Universität BerlinBerlinGermany
| | - Volker Haucke
- Department of Biology, Chemistry, PharmacyFreie Universität BerlinBerlinGermany
- Department of Molecular Pharmacology and Cell BiologyLeibniz Forschungsinstitut für Molekulare Pharmakologie (FMP)BerlinGermany
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6
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Song DY, Yuan L, Cui N, Feng C, Meng L, Wang XH, Xiang M, Liu D, Wang C, Zhang Z, Li JY, Li W. α-Synuclein induces deficiency in clathrin-mediated endocytosis through inhibiting synaptojanin1 expression. J Neurochem 2023; 167:461-484. [PMID: 37788328 DOI: 10.1111/jnc.15974] [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: 06/15/2023] [Revised: 08/13/2023] [Accepted: 09/13/2023] [Indexed: 10/05/2023]
Abstract
Parkinson's disease (PD) is an age-related chronic neurological disorder, mainly characterized by the pathological feature of α-synuclein (α-syn) aggregation, with the exact disease pathogenesis unclear. During the onset and progression of PD, synaptic dysfunction, including dysregulation of axonal transport, impaired exocytosis, and endocytosis are identified as crucial events of PD pathogenesis. It has been reported that over-expression of α-syn impairs clathrin-mediated endocytosis (CME) in the synapses. However, the underlying mechanisms still needs to be explored. In this study, we investigated the molecular events underlying the synaptic dysfunction caused by over-expression of wild-type human α-syn and its mutant form, involving series of proteins participating in CME. We found that excessive human α-syn causes impaired fission and uncoating of clathrin-coated vesicles during synaptic vesicle recycling, leading to reduced clustering of synaptic vesicles near the active zone and increased size of plasma membrane and number of endocytic intermediates. Furthermore, over-expressed human α-syn induced changes of CME-associated proteins, among which synaptojanin1 (SYNJ1) showed significant reduction in various brain regions. Over-expression of SYNJ1 in primary hippocampal neurons from α-syn transgenic mice recovered the synaptic vesicle density, clustering and endocytosis. Using fluorescence-conjugated transferrin, we demonstrated that SYNJ1 re-boosted the CME activity by restoring the phosphatidylinositol-4,5-bisphosphate homeostasis. Our data suggested that over-expression of α-syn disrupts synaptic function through interfering with vesicle recycling, which could be alleviated by re-availing of SYNJ1. Our study unrevealed a molecular mechanism of the synaptic dysfunction in PD pathogenesis and provided a potential therapeutic target for treating PD.
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Affiliation(s)
- Dong-Yan Song
- Institute of Neuroscience, College of Life and Health Sciences, Northeastern University, Shenyang, China
- Laboratory of Research in Parkinson's Disease and Related Disorders, Health Sciences Institute, Key Laboratory of Major Chronic Diseases of Nervous System of Liaoning Province, China Medical University, Shenyang, China
| | - Lin Yuan
- Laboratory of Research in Parkinson's Disease and Related Disorders, Health Sciences Institute, Key Laboratory of Major Chronic Diseases of Nervous System of Liaoning Province, China Medical University, Shenyang, China
| | - Na Cui
- Laboratory of Research in Parkinson's Disease and Related Disorders, Health Sciences Institute, Key Laboratory of Major Chronic Diseases of Nervous System of Liaoning Province, China Medical University, Shenyang, China
| | - Cong Feng
- Laboratory of Research in Parkinson's Disease and Related Disorders, Health Sciences Institute, Key Laboratory of Major Chronic Diseases of Nervous System of Liaoning Province, China Medical University, Shenyang, China
| | - Lanxia Meng
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Xin-He Wang
- Institute of Neuroscience, College of Life and Health Sciences, Northeastern University, Shenyang, China
| | - Man Xiang
- Laboratory of Research in Parkinson's Disease and Related Disorders, Health Sciences Institute, Key Laboratory of Major Chronic Diseases of Nervous System of Liaoning Province, China Medical University, Shenyang, China
| | - Di Liu
- Institute of Neuroscience, College of Life and Health Sciences, Northeastern University, Shenyang, China
| | - Chun Wang
- Laboratory of Research in Parkinson's Disease and Related Disorders, Health Sciences Institute, Key Laboratory of Major Chronic Diseases of Nervous System of Liaoning Province, China Medical University, Shenyang, China
| | - Zhentao Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Jia-Yi Li
- Laboratory of Research in Parkinson's Disease and Related Disorders, Health Sciences Institute, Key Laboratory of Major Chronic Diseases of Nervous System of Liaoning Province, China Medical University, Shenyang, China
- Neural Plasticity and Repair Unit, Department of Experimental Medical Sciences, Lund University, Lund, Sweden
| | - Wen Li
- Laboratory of Research in Parkinson's Disease and Related Disorders, Health Sciences Institute, Key Laboratory of Major Chronic Diseases of Nervous System of Liaoning Province, China Medical University, Shenyang, China
- Neural Plasticity and Repair Unit, Department of Experimental Medical Sciences, Lund University, Lund, Sweden
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7
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Muraleedharan A, Vanderperre B. The endo-lysosomal system in Parkinson's disease: expanding the horizon. J Mol Biol 2023:168140. [PMID: 37148997 DOI: 10.1016/j.jmb.2023.168140] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 04/22/2023] [Accepted: 04/27/2023] [Indexed: 05/08/2023]
Abstract
Parkinson's disease (PD) is the second most common neurodegenerative disorder after Alzheimer's disease, and its prevalence is increasing with age. A wealth of genetic evidence indicates that the endo-lysosomal system is a major pathway driving PD pathogenesis with a growing number of genes encoding endo-lysosomal proteins identified as risk factors for PD, making it a promising target for therapeutic intervention. However, detailed knowledge and understanding of the molecular mechanisms linking these genes to the disease are available for only a handful of them (e.g. LRRK2, GBA1, VPS35). Taking on the challenge of studying poorly characterized genes and proteins can be daunting, due to the limited availability of tools and knowledge from previous literature. This review aims at providing a valuable source of molecular and cellular insights into the biology of lesser-studied PD-linked endo-lysosomal genes, to help and encourage researchers in filling the knowledge gap around these less popular genetic players. Specific endo-lysosomal pathways discussed range from endocytosis, sorting, and vesicular trafficking to the regulation of membrane lipids of these membrane-bound organelles and the specific enzymatic activities they contain. We also provide perspectives on future challenges that the community needs to tackle and propose approaches to move forward in our understanding of these poorly studied endo-lysosomal genes. This will help harness their potential in designing innovative and efficient treatments to ultimately re-establish neuronal homeostasis in PD but also other diseases involving endo-lysosomal dysfunction.
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Affiliation(s)
- Amitha Muraleedharan
- Centre d'Excellence en Recherche sur les Maladies Orphelines - Fondation Courtois and Biological Sciences Department, Université du Québec à Montréal
| | - Benoît Vanderperre
- Centre d'Excellence en Recherche sur les Maladies Orphelines - Fondation Courtois and Biological Sciences Department, Université du Québec à Montréal
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8
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Ng XY, Wu Y, Lin Y, Yaqoob SM, Greene LE, De Camilli P, Cao M. Mutations in Parkinsonism-linked endocytic proteins synaptojanin1 and auxilin have synergistic effects on dopaminergic axonal pathology. NPJ Parkinsons Dis 2023; 9:26. [PMID: 36792618 PMCID: PMC9932162 DOI: 10.1038/s41531-023-00465-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 01/20/2023] [Indexed: 02/17/2023] Open
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder characterized by defective dopaminergic (DAergic) input to the striatum. Mutations in two genes encoding synaptically enriched clathrin-uncoating factors, synaptojanin 1 (SJ1) and auxilin, have been implicated in atypical Parkinsonism. SJ1 knock-in (SJ1-KIRQ) mice carrying a disease-linked mutation display neurological manifestations reminiscent of Parkinsonism. Here we report that auxilin knockout (Aux-KO) mice display dystrophic changes of a subset of nigrostriatal DAergic terminals similar to those of SJ1-KIRQ mice. Furthermore, Aux-KO/SJ1-KIRQ double mutant mice have shorter lifespan and more severe synaptic defects than single mutant mice. These include increase in dystrophic striatal nerve terminals positive for DAergic markers and for the PD risk protein SV2C, as well as adaptive changes in striatal interneurons. The synergistic effect of the two mutations demonstrates a special lability of DAergic neurons to defects in clathrin uncoating, with implications for PD pathogenesis in at least some forms of this condition.
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Affiliation(s)
- Xin Yi Ng
- Programme in Neuroscience and Behavioural Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Yumei Wu
- Departments of Neuroscience and Cell Biology, Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT, 06510, USA
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
| | - Youneng Lin
- Programme in Neuroscience and Behavioural Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Sidra Mohamed Yaqoob
- Programme in Neuroscience and Behavioural Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Lois E Greene
- Laboratory of Cell Biology, NHLBI, National Institutes of Health, Bethesda, MD, USA
| | - Pietro De Camilli
- Departments of Neuroscience and Cell Biology, Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT, 06510, USA
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA
| | - Mian Cao
- Programme in Neuroscience and Behavioural Disorders, Duke-NUS Medical School, Singapore, Singapore.
- Department of Physiology, National University of Singapore, Singapore, Singapore.
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9
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Synaptic vesicle proteins and ATG9A self-organize in distinct vesicle phases within synapsin condensates. Nat Commun 2023; 14:455. [PMID: 36709207 PMCID: PMC9884207 DOI: 10.1038/s41467-023-36081-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Accepted: 01/16/2023] [Indexed: 01/30/2023] Open
Abstract
Ectopic expression in fibroblasts of synapsin 1 and synaptophysin is sufficient to generate condensates of vesicles highly reminiscent of synaptic vesicle (SV) clusters and with liquid-like properties. Here we show that unlike synaptophysin, other major integral SV membrane proteins fail to form condensates with synapsin, but co-assemble into the clusters formed by synaptophysin and synapsin in this ectopic expression system. Another vesicle membrane protein, ATG9A, undergoes activity-dependent exo-endocytosis at synapses, raising questions about the relation of ATG9A traffic to the traffic of SVs. We find that both in fibroblasts and in nerve terminals ATG9A does not co-assemble into synaptophysin-positive vesicle condensates but localizes on a distinct class of vesicles that also assembles with synapsin but into a distinct phase. Our findings suggest that ATG9A undergoes differential sorting relative to SV proteins and also point to a dual role of synapsin in controlling clustering at synapses of SVs and ATG9A vesicles.
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10
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Molecular Mechanism and Regulation of Autophagy and Its Potential Role in Epilepsy. Cells 2022; 11:cells11172621. [PMID: 36078029 PMCID: PMC9455075 DOI: 10.3390/cells11172621] [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: 07/20/2022] [Revised: 08/14/2022] [Accepted: 08/22/2022] [Indexed: 01/18/2023] Open
Abstract
Autophagy is an evolutionally conserved degradation mechanism for maintaining cell homeostasis whereby cytoplasmic components are wrapped in autophagosomes and subsequently delivered to lysosomes for degradation. This process requires the concerted actions of multiple autophagy-related proteins and accessory regulators. In neurons, autophagy is dynamically regulated in different compartments including soma, axons, and dendrites. It determines the turnover of selected materials in a spatiotemporal control manner, which facilitates the formation of specialized neuronal functions. It is not surprising, therefore, that dysfunctional autophagy occurs in epilepsy, mainly caused by an imbalance between excitation and inhibition in the brain. In recent years, much attention has been focused on how autophagy may cause the development of epilepsy. In this article, we overview the historical landmarks and distinct types of autophagy, recent progress in the core machinery and regulation of autophagy, and biological roles of autophagy in homeostatic maintenance of neuronal structures and functions, with a particular focus on synaptic plasticity. We also discuss the relevance of autophagy mechanisms to the pathophysiology of epileptogenesis.
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11
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Jensen JB, Falkenburger BH, Dickson EJ, de la Cruz L, Dai G, Myeong J, Jung SR, Kruse M, Vivas O, Suh BC, Hille B. Biophysical physiology of phosphoinositide rapid dynamics and regulation in living cells. J Gen Physiol 2022; 154:e202113074. [PMID: 35583815 PMCID: PMC9121023 DOI: 10.1085/jgp.202113074] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 04/28/2022] [Indexed: 01/07/2023] Open
Abstract
Phosphoinositide membrane lipids are ubiquitous low-abundance signaling molecules. They direct many physiological processes that involve ion channels, membrane identification, fusion of membrane vesicles, and vesicular endocytosis. Pools of these lipids are continually broken down and refilled in living cells, and the rates of some of these reactions are strongly accelerated by physiological stimuli. Recent biophysical experiments described here measure and model the kinetics and regulation of these lipid signals in intact cells. Rapid on-line monitoring of phosphoinositide metabolism is made possible by optical tools and electrophysiology. The experiments reviewed here reveal that as for other cellular second messengers, the dynamic turnover and lifetimes of membrane phosphoinositides are measured in seconds, controlling and timing rapid physiological responses, and the signaling is under strong metabolic regulation. The underlying mechanisms of this metabolic regulation remain questions for the future.
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Affiliation(s)
- Jill B. Jensen
- Department of Physiology and Biophysics, University of Washington, Seattle, WA
| | | | - Eamonn J. Dickson
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA
| | - Lizbeth de la Cruz
- Department of Physiology and Biophysics, University of Washington, Seattle, WA
| | - Gucan Dai
- Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO
| | - Jongyun Myeong
- Department of Cell Biology and Physiology, Washington University in St. Louis, St. Louis, MO
| | | | - Martin Kruse
- Department of Biology and Program in Neuroscience, Bates College, Lewiston, ME
| | - Oscar Vivas
- Department of Physiology and Biophysics, University of Washington, Seattle, WA
| | - Byung-Chang Suh
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, Republic of Korea
| | - Bertil Hille
- Department of Physiology and Biophysics, University of Washington, Seattle, WA
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12
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Vozdek R, Pramstaller PP, Hicks AA. Functional Screening of Parkinson's Disease Susceptibility Genes to Identify Novel Modulators of α-Synuclein Neurotoxicity in Caenorhabditis elegans. Front Aging Neurosci 2022; 14:806000. [PMID: 35572147 PMCID: PMC9093606 DOI: 10.3389/fnagi.2022.806000] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 03/18/2022] [Indexed: 11/24/2022] Open
Abstract
Idiopathic Parkinson's disease (PD) is characterized by progressive loss of dopaminergic (DA) neurons during aging. The pathological hallmark of PD is the Lewy body detected in postmortem brain tissue, which is mainly composed of aggregated α-Synuclein (αSyn). However, it is estimated that 90% of PD cases have unknown pathogenetic triggers. Here, we generated a new transgenic Caenorhabditis elegans PD model eraIs1 expressing green fluorescent protein- (GFP-) based reporter of human αSyn in DA neurons, and exhibited a nice readout of the developed αSyn inclusions in DA neurons, leading to their degeneration during aging. Using these animals in a preliminary reverse genetic screening of >100-PD genome-wide association study- (GWAS-) based susceptibility genes, we identified 28 orthologs of C. elegans and their inactivation altered the phenotype of eraIs1; 10 knockdowns exhibited reduced penetrance of αSyn:Venus inclusions formed in the axons of cephalic (CEP) DA neurons, 18 knockdowns exhibited increased penetrance of disrupted CEP dendrite integrity among which nine knockdowns also exhibited disrupted neuronal morphology independent of the expressed αSyn reporter. Loss-of-function alleles of the five identified genes, such as sac-2, rig-6 or lfe-2, unc-43, and nsf-1, modulated the corresponding eraIs1 phenotype, respectively, and supported the RNA interference (RNAi) data. The Western blot analysis showed that the levels of insoluble αSyn:Venus were not correlated with the observed phenotypes in these mutants. However, RNAi of 12 identified modulators reduced the formation of pro-aggregating polyglutamine Q40:YFP foci in muscle cells, suggesting the possible role of these genes in cellular proteotoxicity. Therefore, modulators identified by their associated biological pathways, such as calcium signaling or vesicular trafficking, represent new potential therapeutic targets for neurodegenerative proteopathies and other diseases associated with aging.
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Affiliation(s)
- Roman Vozdek
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, Bolzano, Italy
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13
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Yang S, Park D, Manning L, Hill SE, Cao M, Xuan Z, Gonzalez I, Dong Y, Clark B, Shao L, Okeke I, Almoril-Porras A, Bai J, De Camilli P, Colón-Ramos DA. Presynaptic autophagy is coupled to the synaptic vesicle cycle via ATG-9. Neuron 2022; 110:824-840.e10. [PMID: 35065714 PMCID: PMC9017068 DOI: 10.1016/j.neuron.2021.12.031] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 10/20/2021] [Accepted: 12/20/2021] [Indexed: 01/01/2023]
Abstract
Autophagy is a cellular degradation pathway essential for neuronal health and function. Autophagosome biogenesis occurs at synapses, is locally regulated, and increases in response to neuronal activity. The mechanisms that couple autophagosome biogenesis to synaptic activity remain unknown. In this study, we determine that trafficking of ATG-9, the only transmembrane protein in the core autophagy pathway, links the synaptic vesicle cycle with autophagy. ATG-9-positive vesicles in C. elegans are generated from the trans-Golgi network via AP-3-dependent budding and delivered to presynaptic sites. At presynaptic sites, ATG-9 undergoes exo-endocytosis in an activity-dependent manner. Mutations that disrupt endocytosis, including a lesion in synaptojanin 1 associated with Parkinson's disease, result in abnormal ATG-9 accumulation at clathrin-rich synaptic foci and defects in activity-induced presynaptic autophagy. Our findings uncover regulated key steps of ATG-9 trafficking at presynaptic sites and provide evidence that ATG-9 exo-endocytosis couples autophagosome biogenesis at presynaptic sites with the activity-dependent synaptic vesicle cycle.
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Affiliation(s)
- Sisi Yang
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Departments of Neuroscience and of Cell Biology, Yale University School of Medicine, 260 Whitney Avenue, YSB C167, New Haven, CT 06511, USA
| | - Daehun Park
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Departments of Neuroscience and of Cell Biology, Yale University School of Medicine, 260 Whitney Avenue, YSB C167, New Haven, CT 06511, USA; Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Laura Manning
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Departments of Neuroscience and of Cell Biology, Yale University School of Medicine, 260 Whitney Avenue, YSB C167, New Haven, CT 06511, USA
| | - Sarah E Hill
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Departments of Neuroscience and of Cell Biology, Yale University School of Medicine, 260 Whitney Avenue, YSB C167, New Haven, CT 06511, USA
| | - Mian Cao
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Departments of Neuroscience and of Cell Biology, Yale University School of Medicine, 260 Whitney Avenue, YSB C167, New Haven, CT 06511, USA; Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Zhao Xuan
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Departments of Neuroscience and of Cell Biology, Yale University School of Medicine, 260 Whitney Avenue, YSB C167, New Haven, CT 06511, USA
| | - Ian Gonzalez
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Departments of Neuroscience and of Cell Biology, Yale University School of Medicine, 260 Whitney Avenue, YSB C167, New Haven, CT 06511, USA
| | - Yongming Dong
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Benjamin Clark
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Departments of Neuroscience and of Cell Biology, Yale University School of Medicine, 260 Whitney Avenue, YSB C167, New Haven, CT 06511, USA
| | - Lin Shao
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Departments of Neuroscience and of Cell Biology, Yale University School of Medicine, 260 Whitney Avenue, YSB C167, New Haven, CT 06511, USA
| | - Ifechukwu Okeke
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Departments of Neuroscience and of Cell Biology, Yale University School of Medicine, 260 Whitney Avenue, YSB C167, New Haven, CT 06511, USA
| | - Agustin Almoril-Porras
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Departments of Neuroscience and of Cell Biology, Yale University School of Medicine, 260 Whitney Avenue, YSB C167, New Haven, CT 06511, USA
| | - Jihong Bai
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Pietro De Camilli
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Departments of Neuroscience and of Cell Biology, Yale University School of Medicine, 260 Whitney Avenue, YSB C167, New Haven, CT 06511, USA; Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510, USA; Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Daniel A Colón-Ramos
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Departments of Neuroscience and of Cell Biology, Yale University School of Medicine, 260 Whitney Avenue, YSB C167, New Haven, CT 06511, USA; Instituto de Neurobiología José del Castillo, Recinto de Ciencias Médicas, Universidad de Puerto Rico, 201 Boulevard del Valle, San Juan, PR 00901, USA; Wu Tsai Institute, Yale University, New Haven, CT 06510, USA.
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14
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Xing Y, Sapuan AH, Martín-Bastida A, Naidu S, Tench C, Evans J, Sare G, Schwarz ST, Al-Bachari S, Parkes LM, Kanavou S, Raw J, Silverdale M, Bajaj N, Pavese N, Burn D, Piccini P, Grosset DG, Auer DP. Neuromelanin-MRI to Quantify and Track Nigral Depigmentation in Parkinson's Disease: A Multicenter Longitudinal Study Using Template-Based Standardized Analysis. Mov Disord 2022; 37:1028-1039. [PMID: 35165920 PMCID: PMC9303322 DOI: 10.1002/mds.28934] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 11/24/2021] [Accepted: 01/09/2022] [Indexed: 12/15/2022] Open
Abstract
Background Clinical diagnosis and monitoring of Parkinson's disease (PD) remain challenging because of the lack of an established biomarker. Neuromelanin‐magnetic resonance imaging (NM‐MRI) is an emerging biomarker of nigral depigmentation indexing the loss of melanized neurons but has unknown prospective diagnostic and tracking performance in multicenter settings. Objectives The aim was to investigate the diagnostic accuracy of NM‐MRI in early PD in a multiprotocol setting and to determine and compare serial NM‐MRI changes in PD and controls. Methods In this longitudinal case–control 3 T MRI study, 148 patients and 97 controls were included from six UK clinical centers, of whom 140 underwent a second scan after 1.5 to 3 years. An automated template‐based analysis was applied for subregional substantia nigra NM‐MRI contrast and volume assessment. A point estimate of the period of prediagnostic depigmentation was computed. Results All NM metrics performed well to discriminate patients from controls, with receiver operating characteristic showing 85% accuracy for ventral NM contrast and 83% for volume. Generalizability using a priori volume cutoff was good (79% accuracy). Serial MRI demonstrated accelerated NM loss in patients compared to controls. Ventral NM contrast loss was point estimated to start 5 to 6 years before clinical diagnosis. Ventral nigral depigmentation was greater in the most affected side, more severe cases, and nigral NM volume change correlated with change in motor severity. Conclusions We demonstrate that NM‐MRI provides clinically useful diagnostic information in early PD across protocols, platforms, and sites. It provides methods and estimated depigmentation rates that highlight the potential to detect preclinical PD and track progression for biomarker‐enabled clinical trials. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society
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Affiliation(s)
- Yue Xing
- School of Medicine, Mental Health & Clinical Neurosciences, Nottingham, United Kingdom.,Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom.,National Institute for Health Research, Nottingham Biomedical Research Centre, Nottingham, United Kingdom
| | - Abdul Halim Sapuan
- School of Medicine, Mental Health & Clinical Neurosciences, Nottingham, United Kingdom.,Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom.,National Institute for Health Research, Nottingham Biomedical Research Centre, Nottingham, United Kingdom
| | - Antonio Martín-Bastida
- Division of Neurology, Imperial College London, London, United Kingdom.,Department of Neurology and Neurosciences, Clínica Universidad de Navarra, Pamplona-Madrid, Spain
| | - Saadnah Naidu
- School of Medicine, Mental Health & Clinical Neurosciences, Nottingham, United Kingdom.,Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom.,Neurology, Nottingham University Hospital Trust, Nottingham, United Kingdom
| | - Christopher Tench
- School of Medicine, Mental Health & Clinical Neurosciences, Nottingham, United Kingdom.,Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom.,National Institute for Health Research, Nottingham Biomedical Research Centre, Nottingham, United Kingdom
| | - Jonathan Evans
- Neurology, Nottingham University Hospital Trust, Nottingham, United Kingdom
| | - Gillian Sare
- Neurology, Nottingham University Hospital Trust, Nottingham, United Kingdom
| | - Stefan T Schwarz
- School of Medicine, Mental Health & Clinical Neurosciences, Nottingham, United Kingdom.,Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom.,Department of Radiology, Cardiff and Vale University Health Board, Cardiff, United Kingdom
| | - Sarah Al-Bachari
- Division of Neuroscience and Experimental Psychology, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, United Kingdom.,Lancaster Medical School, Lancaster University, Lancaster, United Kingdom.,Department of Neurology, Lancashire Teaching Hospitals NHS Foundation Trust, Preston, United Kingdom
| | - Laura M Parkes
- Division of Neuroscience & Experimental Psychology, School of Biological Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Sofia Kanavou
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Jason Raw
- Pennine Acute Hospitals NHS Trust, Oldham, United Kingdom
| | - Monty Silverdale
- Division of Neurology, Salford Royal NHS Foundation Trust, Manchester Academic Health Science Centre, University of Manchester, Manchester, United Kingdom
| | - Nin Bajaj
- School of Medicine, Mental Health & Clinical Neurosciences, Nottingham, United Kingdom.,Spire Nottingham Hospital, Nottingham, United Kingdom
| | - Nicola Pavese
- Newcastle Magnetic Resonance Centre & Positron Emission Tomography Centre and Clinical Ageing Research Unit, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - David Burn
- Faculty of Medical Sciences, The Medical School, Framlington Place, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Paola Piccini
- Division of Neurology, Imperial College London, London, United Kingdom.,Department of Brain Science, Imperial College London, London, United Kingdom
| | - Donald G Grosset
- Institute for Neurological Sciences, Queen Elizabeth University Hospital, Glasgow, United Kingdom
| | - Dorothee P Auer
- School of Medicine, Mental Health & Clinical Neurosciences, Nottingham, United Kingdom.,Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom.,National Institute for Health Research, Nottingham Biomedical Research Centre, Nottingham, United Kingdom
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15
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Zhou Q, Lin J, Yan Y, Meng S, Liao H, Chen R, He G, Zhu Y, He C, Mao K, Wang J, Zhang J, Zhou Z, Xiao Z. INPP5F translocates into cytoplasm and interacts with ASPH to promote tumor growth in hepatocellular carcinoma. J Exp Clin Cancer Res 2022; 41:13. [PMID: 34996491 PMCID: PMC8740451 DOI: 10.1186/s13046-021-02216-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 12/07/2021] [Indexed: 11/10/2022] Open
Abstract
Background Increasing evidence has suggested inositol polyphosphate 5-phosphatase family contributes to tumorigenesis and tumor progression. However, the role of INPP5F in hepatocellular carcinoma (HCC) and its underlying mechanisms is unclear. Methods The expression of INPP5F in HCC was analyzed in public databases and our clinical specimens. The biological functions of INPP5F were investigated in vitro and vivo. The molecular mechanism of INPP5F in regulating tumor growth were studied by transcriptome-sequencing analysis, mass spectrometry analysis, immunoprecipitation assay and immunofluorescence assay. Results High expression of INPP5F was found in HCC tissues and was associated with poor prognosis in HCC patients. Overexpression of INPP5F promoted HCC cell proliferation, and vice versa. Knockdown of INPP5F suppressed tumor growth in vivo. Results from transcriptome-sequencing analysis showed INPP5F not only regulated a series of cell cycle related genes expression (c-MYC and cyclin E1), but also promoted many aerobic glycolysis related genes expression. Further studies confirmed that INPP5F could enhance lactate production and glucose consumption in HCC cell. Mechanistically, INPP5F activated Notch signaling pathway and upregulated c-MYC and cyclin E1 in HCC via interacting with ASPH. Interestingly, INPP5F was commonly nuclear-located in cells of adjacent non-tumor tissues, while in HCC, cytoplasm-located was more common. LMB (nuclear export inhibitor) treatment restricted INPP5F in nucleus and was associated with inhibition of Notch signaling and cell proliferation. Sequence of nuclear localization signals (NLSs) and nuclear export signals (NESs) in INPP5F aminoacidic sequence were then identified. Alteration of the NLSs or NESs influenced the localization of INPP5F and the expression of its downstream molecules. Furthermore, we found INPP5F interacted with both exportin and importin through NESs and NLSs, respectively, but the interaction with exportin was stronger, leading to cytoplasmic localization of INPP5F in HCC. Conclusion These findings indicate that INPP5F functions as an oncogene in HCC via a translocation mechanism and activating ASPH-mediated Notch signaling pathway. INPP5F may serve as a potential therapeutic target for HCC patients. Supplementary Information The online version contains supplementary material available at 10.1186/s13046-021-02216-x.
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Affiliation(s)
- Qianlei Zhou
- Department of Hepatobiliary Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.,Guangdong Province Key laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.,Department of Thyroid Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Jianhong Lin
- Department of Hepatobiliary Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.,Guangdong Province Key laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Yongcong Yan
- Department of Hepatobiliary Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.,Guangdong Province Key laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Shiyu Meng
- Guangdong Province Key laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.,Department of Anesthesiology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Hao Liao
- Department of Hepatobiliary Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.,Guangdong Province Key laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Ruibin Chen
- Department of Hepatobiliary Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.,Guangdong Province Key laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Gui He
- Cellular & Molecular Diagnostics Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Yue Zhu
- Guangdong Province Key laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.,Department of Thyroid Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Chuanchao He
- Department of Hepatobiliary Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.,Guangdong Province Key laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Kai Mao
- Department of Hepatobiliary Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.,Guangdong Province Key laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Jie Wang
- Department of Hepatobiliary Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.,Guangdong Province Key laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China
| | - Jianlong Zhang
- Department of Hepatobiliary Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China. .,Guangdong Province Key laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.
| | - Zhenyu Zhou
- Department of Hepatobiliary Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China. .,Guangdong Province Key laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.
| | - Zhiyu Xiao
- Department of Hepatobiliary Surgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China. .,Guangdong Province Key laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, 510120, China.
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16
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Ho D, Schierding W, Farrow SL, Cooper AA, Kempa-Liehr AW, O’Sullivan JM. Machine Learning Identifies Six Genetic Variants and Alterations in the Heart Atrial Appendage as Key Contributors to PD Risk Predictivity. Front Genet 2022; 12:785436. [PMID: 35047012 PMCID: PMC8762216 DOI: 10.3389/fgene.2021.785436] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 11/09/2021] [Indexed: 12/14/2022] Open
Abstract
Parkinson's disease (PD) is a complex neurodegenerative disease with a range of causes and clinical presentations. Over 76 genetic loci (comprising 90 SNPs) have been associated with PD by the most recent GWAS meta-analysis. Most of these PD-associated variants are located in non-coding regions of the genome and it is difficult to understand what they are doing and how they contribute to the aetiology of PD. We hypothesised that PD-associated genetic variants modulate disease risk through tissue-specific expression quantitative trait loci (eQTL) effects. We developed and validated a machine learning approach that integrated tissue-specific eQTL data on known PD-associated genetic variants with PD case and control genotypes from the Wellcome Trust Case Control Consortium. In so doing, our analysis ranked the tissue-specific transcription effects for PD-associated genetic variants and estimated their relative contributions to PD risk. We identified roles for SNPs that are connected with INPP5P, CNTN1, GBA and SNCA in PD. Ranking the variants and tissue-specific eQTL effects contributing most to the machine learning model suggested a key role in the risk of developing PD for two variants (rs7617877 and rs6808178) and eQTL associated transcriptional changes of EAF1-AS1 within the heart atrial appendage. Similarly, effects associated with eQTLs located within the Brain Cerebellum were also recognized to confer major PD risk. These findings were replicated in two additional, independent cohorts (the UK Biobank, and NeuroX) and thus warrant further mechanistic investigations to determine if these transcriptional changes could act as early contributors to PD risk and disease development.
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Affiliation(s)
- Daniel Ho
- Liggins Institute, The University of Auckland, Auckland, New Zealand
| | - William Schierding
- Liggins Institute, The University of Auckland, Auckland, New Zealand
- MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, United Kingdom
| | - Sophie L. Farrow
- Liggins Institute, The University of Auckland, Auckland, New Zealand
- MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, United Kingdom
| | - Antony A. Cooper
- Australian Parkinsons Mission, Garvan Institute of Medical Research, Sydney, NSW, Australia
- St Vincent’s Clinical School, UNSW Sydney, Sydney, NSW, Australia
| | | | - Justin M. O’Sullivan
- Liggins Institute, The University of Auckland, Auckland, New Zealand
- MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, United Kingdom
- Brain Research New Zealand, The University of Auckland, Auckland, New Zealand
- The Maurice Wilkins Centre, The University of Auckland, Auckland, New Zealand
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17
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Xue F, Gao L, Chen T, Chen H, Zhang H, Wang T, Han Z, Gao S, Wang L, Hu Y, Tang J, Huang L, Liu G, Zhang Y. Parkinson's Disease rs117896735 Variant Regulates INPP5F Expression in Brain Tissues and Increases Risk of Alzheimer's Disease. J Alzheimers Dis 2022; 89:67-77. [PMID: 35848021 DOI: 10.3233/jad-220086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Both INPP5D and INPP5F are members of INPP5 family. INPP5F rs117896735 variant was associated with Parkinson's disease (PD) risk, and INPP5D was an Alzheimer's disease (AD) risk gene. However, it remains unclear about the roles of INPP5F rs117896735 variant in AD. OBJECTIVE We aim to investigate the roles of rs117896735 in AD. METHODS First, we conducted a candidate variant study to evaluate the association of rs117896735 variant with AD risk using the large-scale AD GWAS dataset. Second, we conducted a gene expression analysis of INPP5F to investigate the expression difference of INPP5F in different human tissues using two large-scale gene expression datasets. Third, we conducted an expression quantitative trait loci analysis to evaluate whether rs117896735 variant regulate the expression of INPP5F. Fourth, we explore the potentially differential expression of INPP5F in AD and control using multiple AD-control gene expression datasets in human brain tissues and whole blood. RESULTS We found that 1) rs117896735 A allele was associated with the increased risk of AD with OR = 1.15, 95% CI 1.005-1.315, p = 0.042; 2) rs117896735 A allele could increase INPP5F expression in multiple human tissues; 3) INPP5F showed different expression in different human tissues, especially in brain tissues; 4) INPP5F showed significant expression dysregulation in AD compared with controls in human brain tissues. CONCLUSION Conclusion: We demonstrate that PD rs117896735 variant could regulate INPP5F expression in brain tissues and increase the risk of AD. These finding may provide important information about the role of rs117896735 in AD.
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Affiliation(s)
- Feng Xue
- Department of Neurosurgery, Tianjin Hospital of ITCWM Nan Kai Hospital, Tianjin, China
| | - Luyan Gao
- Department of Neurology, Tianjin Fourth Central Hospital, The Fourth Central Hospital Affiliated to Nankai University, The Fourth Central Clinical College of Tianjin Medical University, Tianjin, China
| | - TingTing Chen
- Department of Oncology, Tianjin Hospital of ITCWM Nan Kai Hospital, Tianjin, China
| | - Hongyuan Chen
- Department of Neurology, The Second Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Haihua Zhang
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Tao Wang
- Chinese Institute for Brain Research, Beijing, China
| | - Zhifa Han
- School of Medicine, School of Pharmaceutical Sciences, THU-PKU Center for Life Sciences, Tsinghua University, Beijing, China
| | - Shan Gao
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Longcai Wang
- Department of Anesthesiology, The Affiliated Hospital of Weifang Medical University, Weifang, China
| | - Yang Hu
- School of Life Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Jiangwei Tang
- Department of Neurology, Tianjin Fourth Central Hospital, The Fourth Central Hospital Affiliated to Nankai University, The Fourth Central Clinical College of Tianjin Medical University, Tianjin, China
| | - Lei Huang
- Department of Neurology, Tianjin Fourth Central Hospital, The Fourth Central Hospital Affiliated to Nankai University, The Fourth Central Clinical College of Tianjin Medical University, Tianjin, China
| | - Guiyou Liu
- Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
- Chinese Institute for Brain Research, Beijing, China
- Beijing Key Laboratory of Hypoxia Translational Medicine, National Engineering Laboratory of Internet Medical Diagnosis and Treatment Technology, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Yan Zhang
- Department of Pathology, The Affiliated Hospital of Weifang Medical University, Weifang, China
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18
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Choudhry H, Aggarwal M, Pan PY. Mini-review: Synaptojanin 1 and its implications in membrane trafficking. Neurosci Lett 2021; 765:136288. [PMID: 34637856 PMCID: PMC8572151 DOI: 10.1016/j.neulet.2021.136288] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 10/03/2021] [Accepted: 10/05/2021] [Indexed: 12/04/2022]
Abstract
This mini-review aims to summarize a growing body of literature on synaptojanin 1 (Synj1), a phosphoinositide phosphatase that was initially known to have a prominent role in synaptic vesicle recycling. Synj1 is coded by the SYNJ1 gene, whose mutations and variants are associated with an increasing number of neurological disorders. To better understand the mechanistic role of Synj1 in disease pathogenesis, we review details of phosphoinositide signaling pathways and the reported involvement of Synj1 in membrane trafficking with a specific focus on Parkinson’s disease (PD). Recent studies have tremendously advanced our understanding of Synj1 protein structure and function while broadening our view of how Synj1 regulates synaptic membrane trafficking and endosomal trafficking in various organisms and cell types. A growing body of evidence points to inefficient membrane trafficking as key pathogenic mechanisms in neurodegenerative diseases associated with abnormal Synj1 expression. Despite significant progress made in the field, the mechanism by which Synj1 connects to trafficking, signaling, and pathogenesis is lacking and remains to be addressed.
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Affiliation(s)
- Hassaam Choudhry
- Dept. of Neuroscience and Cell Biology, Rutgers, Robert Wood Johnson Medical School, 675 Hoes Lane West, Piscataway, NJ 08854, USA
| | - Meha Aggarwal
- Dept. of Neuroscience and Cell Biology, Rutgers, Robert Wood Johnson Medical School, 675 Hoes Lane West, Piscataway, NJ 08854, USA
| | - Ping-Yue Pan
- Dept. of Neuroscience and Cell Biology, Rutgers, Robert Wood Johnson Medical School, 675 Hoes Lane West, Piscataway, NJ 08854, USA.
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19
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Dopaminergic Axons: Key Recitalists in Parkinson's Disease. Neurochem Res 2021; 47:234-248. [PMID: 34637100 DOI: 10.1007/s11064-021-03464-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 10/03/2021] [Accepted: 10/05/2021] [Indexed: 12/20/2022]
Abstract
Parkinson's disease (PD) is associated with dopamine depletion in the striatum owing to the selective and progressive loss of the nigrostriatal dopaminergic neurons, which results in motor dysfunction and secondary clinical manifestations. The dopamine level in the striatum is preserved because of the innervation of the substantia nigra (SN) dopaminergic neurons into it. Therefore, protection of the SN neurons is crucial for maintaining the dopamine level in the striatum and for ensuring the desired motor coordination. Several strategies have been devised to protect the degenerating dopaminergic neurons or to restore the dopamine levels for treating PD. Most of the methods focus exclusively on preventing cell body death in the neurons. Although advances have been made in understanding the disease, the search for disease-modifying drugs is an ongoing process. The present review describes the evidence from studies involving patients with PD as well as PD models that axon terminals are highly vulnerable to exogenous and endogenous insults and degenerate at the early stage of the disease. Impairment of mitochondrial dynamics, Ca2+ homeostasis, axonal transport, and loss of plasticity of axon terminals appear before the neuronal degeneration in PD. Furthermore, distortion of synaptic morphology and reduction of postsynaptic dendritic spines are the neuropathological hallmarks of early-stage disease. Thus, the review proposes a shift in focus from discerning the mechanism of neuronal cell body loss and targeting it to an entirely different approach of preventing axonal degeneration. The review also suggests appropriate strategies to prevent the loss of synaptic terminals, which could induce regrowth of the axon and its auxiliary fibers and might offer relief from the symptomatic features of PD.
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Schechter M, Sharon R. An Emerging Role for Phosphoinositides in the Pathophysiology of Parkinson’s Disease. JOURNAL OF PARKINSON'S DISEASE 2021; 11:1725-1750. [PMID: 34151859 PMCID: PMC8609718 DOI: 10.3233/jpd-212684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Recent data support an involvement of defects in homeostasis of phosphoinositides (PIPs) in the pathophysiology of Parkinson’s disease (PD). Genetic mutations have been identified in genes encoding for PIP-regulating and PIP-interacting proteins, that are associated with familial and sporadic PD. Many of these proteins are implicated in vesicular membrane trafficking, mechanisms that were recently highlighted for their close associations with PD. PIPs are phosphorylated forms of the membrane phospholipid, phosphatidylinositol. Their composition in the vesicle’s membrane of origin, as well as membrane of destination, controls vesicular membrane trafficking. We review the converging evidence that points to the involvement of PIPs in PD. The review describes PD- and PIP-associated proteins implicated in clathrin-mediated endocytosis and autophagy, and highlights the involvement of α-synuclein in these mechanisms.
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Affiliation(s)
- Meir Schechter
- Department of Biochemistry and Molecular Biology, IMRIC, The Hebrew University-Hadassah Medical School, Ein Kerem, Jerusalem, Israel
| | - Ronit Sharon
- Department of Biochemistry and Molecular Biology, IMRIC, The Hebrew University-Hadassah Medical School, Ein Kerem, Jerusalem, Israel
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Hoshino F, Sakane F. The SAC1 phosphatase domain of synaptojanin-1 is activated by interacting with polyunsaturated fatty acid-containing phosphatidic acids. FEBS Lett 2021; 595:2479-2492. [PMID: 34387861 DOI: 10.1002/1873-3468.14177] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 08/10/2021] [Accepted: 08/10/2021] [Indexed: 11/07/2022]
Abstract
Although there are many phosphatidic acid (PA) molecular species based on its fatty acyl compositions, their interacting partners have been poorly investigated. Here, we identified synaptojanin-1 (SYNJ1), a Parkinson's disease-related protein that is essential for regulating clathrin-mediated synaptic vesicle endocytosis via dually dephosphorylating D5 and D4 position phosphates from phosphatidylinositol (PI) (4,5)-bisphosphate, as a 1-stearoyl-2-docosahexaenoyl (18:0/22:6)-PA-binding protein. SYNJ1 failed to substantially associate with other acidic phospholipids. Although SYNJ1 interacted with 18:0/20:4-PA in addition to 18:0/22:6-PA, the association of the enzyme with 16:0/16:0-, 16:0/18:1-, 18:0/18:0- or 18:1/18:1-PA was not considerable. 18:0/20:4- and 18:0/22:6-PAs bound to SYNJ1 via its SAC1 domain, which preferentially hydrolyses D4 position phosphate. Moreover, 18:0/20:4- and 18:0/22:6-PA selectively enhanced the D4-phosphatase activity, but not the D5-phosphatase activity, of SYNJ1.
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Affiliation(s)
- Fumi Hoshino
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, 263-8522, Japan
| | - Fumio Sakane
- Department of Chemistry, Graduate School of Science, Chiba University, Chiba, 263-8522, Japan
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Pan PY, Zhu J, Rizvi A, Zhu X, Tanaka H, Dreyfus CF. Synaptojanin1 deficiency upregulates basal autophagosome formation in astrocytes. J Biol Chem 2021; 297:100873. [PMID: 34126070 PMCID: PMC8258991 DOI: 10.1016/j.jbc.2021.100873] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 06/02/2021] [Accepted: 06/10/2021] [Indexed: 01/07/2023] Open
Abstract
Macroautophagy dysregulation is implicated in multiple neurological disorders, such as Parkinson's disease. While autophagy pathways are heavily researched in heterologous cells and neurons, regulation of autophagy in the astrocyte, the most abundant cell type in the mammalian brain, is less well understood. Missense mutations in the Synj1 gene encoding Synaptojanin1 (Synj1), a neuron-enriched lipid phosphatase, have been linked to Parkinsonism with seizures. Our previous study showed that the Synj1 haploinsufficient (Synj1+/−) mouse exhibits age-dependent autophagy impairment in multiple brain regions. Here, we used cultured astrocytes from Synj1-deficient mice to investigate its role in astrocyte autophagy. We report that Synj1 is expressed in low levels in astrocytes and represses basal autophagosome formation. We demonstrate using cellular imaging that Synj1-deficient astrocytes exhibit hyperactive autophagosome formation, represented by an increase in the size and number of GFP-microtubule-associated protein 1A/1B-light chain 3 structures. Interestingly, Synj1 deficiency is also associated with an impairment in stress-induced autophagy clearance. We show, for the first time, that the Parkinsonism-associated R839C mutation impacts autophagy in astrocytes. The impact of this mutation on the phosphatase function of Synj1 resulted in elevated basal autophagosome formation that mimics Synj1 deletion. We found that the membrane expression of the astrocyte-specific glucose transporter GluT-1 was reduced in Synj1-deficient astrocytes. Consistently, AMP-activated protein kinase activity was elevated, suggesting altered glucose sensing in Synj1-deficient astrocytes. Expressing exogenous GluT-1 in Synj1-deficient astrocytes reversed the autophagy impairment, supporting a role for Synj1 in regulating astrocyte autophagy via disrupting glucose-sensing pathways. Thus, our work suggests a novel mechanism for Synj1-related Parkinsonism involving astrocyte dysfunction.
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Affiliation(s)
- Ping-Yue Pan
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA.
| | - Justin Zhu
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA
| | - Asma Rizvi
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA
| | - Xinyu Zhu
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA
| | - Hikari Tanaka
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA
| | - Cheryl F Dreyfus
- Department of Neuroscience and Cell Biology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA
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Ichise E, Chiyonobu T, Ishikawa M, Tanaka Y, Shibata M, Tozawa T, Taura Y, Yamashita S, Yoshida M, Morimoto M, Higurashi N, Yamamoto T, Okano H, Hirose S. Impaired neuronal activity and differential gene expression in STXBP1 encephalopathy patient iPSC-derived GABAergic neurons. Hum Mol Genet 2021; 30:1337-1348. [PMID: 33961044 DOI: 10.1093/hmg/ddab113] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/10/2021] [Accepted: 04/14/2021] [Indexed: 11/13/2022] Open
Abstract
Syntaxin-binding protein 1 (STXBP1; also called MUNC18-1), encoded by STXBP1, is an essential component of the molecular machinery that controls synaptic vesicle docking and fusion. De novo pathogenic variants of STXBP1 cause a complex set of neurological disturbances, namely STXBP1 encephalopathy (STXBP1-E) that includes epilepsy, neurodevelopmental disorders and neurodegeneration. Several animal studies have suggested the contribution of GABAergic dysfunction in STXBP1-E pathogenesis. However, the pathophysiological changes in GABAergic neurons of these patients are still poorly understood. Here, we exclusively generated GABAergic neurons from STXBP1-E patient-derived induced pluripotent stem cells (iPSCs) by transient expression of the transcription factors ASCL1 and DLX2. We also generated CRISPR/Cas9-edited isogenic iPSC-derived GABAergic (iPSC GABA) neurons as controls. We demonstrated that the reduction in STXBP1 protein levels in patient-derived iPSC GABA neurons was slight (approximately 20%) compared to the control neurons, despite a 50% reduction in STXBP1 mRNA levels. Using a microelectrode array-based assay, we found that patient-derived iPSC GABA neurons exhibited dysfunctional maturation with reduced numbers of spontaneous spikes and bursts. These findings reinforce the idea that GABAergic dysfunction is a crucial contributor to STXBP1-E pathogenesis. Moreover, gene expression analysis revealed specific dysregulation of genes previously implicated in epilepsy, neurodevelopment and neurodegeneration in patient-derived iPSC GABA neurons, namely KCNH1, KCNH5, CNN3, RASGRF1, SEMA3A, SIAH3 and INPP5F. Thus, our study provides new insights for understanding the biological processes underlying the widespread neuropathological features of STXBP1-E.
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Affiliation(s)
- Eisuke Ichise
- Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Tomohiro Chiyonobu
- Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Mitsuru Ishikawa
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Yasuyoshi Tanaka
- Research Institute for the Molecular Pathomechanisms of Epilepsy, Fukuoka University, Fukuoka 814-0180, Japan
| | - Mami Shibata
- Research Institute for the Molecular Pathomechanisms of Epilepsy, Fukuoka University, Fukuoka 814-0180, Japan
| | - Takenori Tozawa
- Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Yoshihiro Taura
- Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Satoshi Yamashita
- Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Michiko Yoshida
- Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Masafumi Morimoto
- Department of Medical Science, School of Nursing, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Norimichi Higurashi
- Department of Pediatrics, Jikei University School of Medicine, Tokyo 105-8461, Japan
| | - Toshiyuki Yamamoto
- Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo 162-8666, Japan
| | - Hideyuki Okano
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Shinichi Hirose
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka 814-0180, Japan
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Meir S, Merav A, Suaad AE, Dana D, Daniel G, Ronit S. α-Synuclein facilitates endocytosis by elevating the steady-state levels of phosphatidylinositol 4,5-bisphosphate.. [DOI: 10.1101/2020.06.18.158709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Abstractα-Synuclein (α-Syn) is a protein implicated in the pathogenesis of Parkinson’s disease (PD). It is an intrinsically disordered protein that binds acidic phospholipids. Growing evidence supports a role for α-Syn in membrane trafficking, including, mechanisms of endocytosis and exocytosis, although the exact role of α-Syn in these mechanisms is currently unclear. Here we have investigated the role of α-Syn in membrane trafficking through its association with acidic phosphoinositides (PIPs), such as phosphatidylinositol 4,5-bisphosphate (PI4,5P2) and phosphatidylinositol 3,4-bisphosphate (PI3,4P2). Our results show that α-Syn colocalizes with PIP2 and the phosphorylated active form of the clathrin adaptor AP2 at clathrin-coated pits. Using endocytosis of transferrin, an indicator of clathrin mediated endocytosis (CME), we find that α-Syn involvement in endocytosis is specifically mediated through PI4,5P2 levels. We further show that the rate of synaptic vesicle (SV) endocytosis is differentially affected by α-Syn mutations. In accord with their effects on PI4,5P2 levels at the plasma membrane, the PD associated E46K and A53T mutations further enhance SV endocytosis. However, neither A30P mutation, nor Lysine to Glutamic acid substitutions at the KTKEGV repeat domain of α-Syn, that interfere with phospholipid binding, affect SV endocytosis. This study provides evidence for a critical involvement of PIPs in α-Syn-mediated membrane trafficking.Significance Statementα-Synuclein (α-Syn) protein is known for its causative role in Parkinson’s disease. α-Syn is normally involved in mechanisms of membrane trafficking, including endocytosis, exocytosis and synaptic vesicles cycling. However, a certain degree of controversy regarding the exact role of α-Syn in these mechanisms persists. Here we show that α-Syn acts to increase plasma membrane levels PI4,5P2 and PI3,4P2 to facilitate clathrin mediated and synaptic vesicles endocytosis. Based on the results, we suggest that α-Syn interactions with the acidic phosphoinositides facilitate a shift in their homeostasis to support endocytosis.
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