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Koppers M, Özkan N, Nguyen HH, Jurriens D, McCaughey J, Nguyen DTM, Li CH, Stucchi R, Altelaar M, MacGillavry HD, Kapitein LC, Hoogenraad CC, Farías GG. Axonal endoplasmic reticulum tubules control local translation via P180/RRBP1-mediated ribosome interactions. Dev Cell 2024:S1534-5807(24)00322-8. [PMID: 38815583 DOI: 10.1016/j.devcel.2024.05.005] [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: 10/12/2022] [Revised: 01/31/2024] [Accepted: 05/09/2024] [Indexed: 06/01/2024]
Abstract
Local mRNA translation in axons is critical for the spatiotemporal regulation of the axonal proteome. A wide variety of mRNAs are localized and translated in axons; however, how protein synthesis is regulated at specific subcellular sites in axons remains unclear. Here, we establish that the axonal endoplasmic reticulum (ER) supports axonal translation in developing rat hippocampal cultured neurons. Axonal ER tubule disruption impairs local translation and ribosome distribution. Using nanoscale resolution imaging, we find that ribosomes make frequent contacts with axonal ER tubules in a translation-dependent manner and are influenced by specific extrinsic cues. We identify P180/RRBP1 as an axonally distributed ribosome receptor that regulates local translation and binds to mRNAs enriched for axonal membrane proteins. Importantly, the impairment of axonal ER-ribosome interactions causes defects in axon morphology. Our results establish a role for the axonal ER in dynamically localizing mRNA translation, which is important for proper neuron development.
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Affiliation(s)
- Max Koppers
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands.
| | - Nazmiye Özkan
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Ha H Nguyen
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Daphne Jurriens
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Janine McCaughey
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Dan T M Nguyen
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Chun Hei Li
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Riccardo Stucchi
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands; Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Maarten Altelaar
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Harold D MacGillavry
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Lukas C Kapitein
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Casper C Hoogenraad
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands; Department of Neuroscience, Genentech, Inc., South San Francisco, CA 94080, USA
| | - Ginny G Farías
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, the Netherlands.
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Wang BR, Wang J, Tian T, Zhang SX, Zhao YQ, Meng SY, Wu ZY, Huang F, Zeng J, Ni J. Genetic correlation, shared loci, but no causality between bipolar disorder and inflammatory bowel disease: A genome-wide pleiotropic analysis. J Affect Disord 2024; 348:167-174. [PMID: 38154582 DOI: 10.1016/j.jad.2023.12.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 11/21/2023] [Accepted: 12/20/2023] [Indexed: 12/30/2023]
Abstract
BACKGROUND AND AIMS The comorbidity between bipolar disorder (BD) and inflammatory bowel disease (IBD) has been widely reported in observational studies. However, unclear whether this comorbidity reflects a shared genetic architecture. METHODS Leveraging large-scale genome-wide association study (GWAS) summary statistics of BD, IBD and its subtypes, ulcerative colitis (UC) and Crohn's disease (CD), we performed a genome-wide pleiotropic analysis to estimate heritability and genetic correlation, identify pleiotropy loci/genes, and explore the shared biological pathway. Mendelian randomization (MR) studies were subsequently employed to infer whether the potential causal relationship is present. RESULTS We found a positive significant genetic correlation between BD and IBD (rg = 0.10, P = 7.00 × 10-4), UC (rg = 0.09, P = 2.90 × 10-3), CD (rg = 0.08, P = 6.10 × 10-3). In cross-trait meta-analysis, a total of 29, 24, and 23 independent SNPs passed the threshold for significant association between BD and IBD, UC, and CD, respectively. We identified five novel pleiotropy genes including ZDHHC2, SCRN1, INPP4B, C1orf123, and BRD3 in both BD and IBD, as well as in its subtypes UC and CD. Pathway enrichment analyses revealed that those pleiotropy genes were mainly enriched in several immune-related signal transduction pathways and cerebral disease-related pathways. MR analyses provided no evidence for a causal relationship between BD and IBD. CONCLUSION Our findings corroborated that shared genetic basis and common biological pathways may explain the comorbidity of BD and IBD. These findings further our understanding of shared genetic mechanisms underlying BD and IBD, and potentially provide points of intervention that may allow the development of new therapies for these co-occurrent disorders.
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Affiliation(s)
- Bing-Ran Wang
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, Anhui 230032, China; Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Hefei, Anhui 230032, China; Department of Clinical Medicine, the Second School of Clinical Medical, Anhui Medical University, Hefei, Anhui 230032, China
| | - Jing Wang
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, Anhui 230032, China; Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Hefei, Anhui 230032, China
| | - Tian Tian
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, Anhui 230032, China; Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Hefei, Anhui 230032, China
| | - Shang-Xin Zhang
- Department of Gastrointestinal Surgery, Department of General Surgery, First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230032, China
| | - Yu-Qiang Zhao
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, Anhui 230032, China; Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Hefei, Anhui 230032, China
| | - Shi-Ying Meng
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, Anhui 230032, China; Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Hefei, Anhui 230032, China
| | - Zhuo-Yi Wu
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, Anhui 230032, China; Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Hefei, Anhui 230032, China
| | - Fen Huang
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, Anhui 230032, China
| | - Jing Zeng
- Department of Gastroenterology, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China.
| | - Jing Ni
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University, Hefei, Anhui 230032, China; Inflammation and Immune Mediated Diseases Laboratory of Anhui Province, Hefei, Anhui 230032, China.
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Pérez-Moreno JJ. Presynaptic endoplasmic reticulum architecture and hereditary spastic paraplegia. Neural Regen Res 2024; 19:485-486. [PMID: 37721265 PMCID: PMC10581549 DOI: 10.4103/1673-5374.380885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 05/25/2023] [Accepted: 06/07/2023] [Indexed: 09/19/2023] Open
Affiliation(s)
- Juan José Pérez-Moreno
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen Del Rocío/CSIC/Universidad de Sevilla, and Departamento de Biología Celular, Facultad de Biología, Universidad de Sevilla, Seville, Spain
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Ma X, Li M, Liu Y, Zhang X, Yang X, Wang Y, Li Y, Wang J, Liu X, Yan Z, Yu X, Wu C. ARTC1-mediated VAPB ADP-ribosylation regulates calcium homeostasis. J Mol Cell Biol 2024; 15:mjad043. [PMID: 37381178 PMCID: PMC10928986 DOI: 10.1093/jmcb/mjad043] [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: 07/26/2022] [Revised: 03/28/2023] [Accepted: 06/26/2023] [Indexed: 06/30/2023] Open
Abstract
Mono-ADP-ribosylation (MARylation) is a post-translational modification that regulates a variety of biological processes, including DNA damage repair, cell proliferation, metabolism, and stress and immune responses. In mammals, MARylation is mainly catalyzed by ADP-ribosyltransferases (ARTs), which consist of two groups: ART cholera toxin-like (ARTCs) and ART diphtheria toxin-like (ARTDs, also known as PARPs). The human ARTC (hARTC) family is composed of four members: two active mono-ADP-ARTs (hARTC1 and hARTC5) and two enzymatically inactive enzymes (hARTC3 and hARTC4). In this study, we systematically examined the homology, expression, and localization pattern of the hARTC family, with a particular focus on hARTC1. Our results showed that hARTC3 interacted with hARTC1 and promoted the enzymatic activity of hARTC1 by stabilizing hARTC1. We also identified vesicle-associated membrane protein-associated protein B (VAPB) as a new target of hARTC1 and pinpointed Arg50 of VAPB as the ADP-ribosylation site. Furthermore, we demonstrated that knockdown of hARTC1 impaired intracellular calcium homeostasis, highlighting the functional importance of hARTC1-mediated VAPB Arg50 ADP-ribosylation in regulating calcium homeostasis. In summary, our study identified a new target of hARTC1 in the endoplasmic reticulum and suggested that ARTC1 plays a role in regulating calcium signaling.
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Affiliation(s)
- Xueyao Ma
- College of Life Sciences, Institute of Life Sciences and Green Development, Hebei University, Baoding 071002, China
| | - Mengyuan Li
- College of Life Sciences, Institute of Life Sciences and Green Development, Hebei University, Baoding 071002, China
| | - Yi Liu
- College of Life Sciences, Institute of Life Sciences and Green Development, Hebei University, Baoding 071002, China
| | - Xuefang Zhang
- College of Life Sciences, Institute of Life Sciences and Green Development, Hebei University, Baoding 071002, China
| | - Xiaoyun Yang
- College of Life Sciences, Institute of Life Sciences and Green Development, Hebei University, Baoding 071002, China
| | - Yun Wang
- Department of Public Health, Affiliated Hospital of Hebei University, Baoding 071000, China
| | - Yipeng Li
- College of Life Sciences, Institute of Life Sciences and Green Development, Hebei University, Baoding 071002, China
| | - Jiayue Wang
- College of Life Sciences, Institute of Life Sciences and Green Development, Hebei University, Baoding 071002, China
| | - Xiuhua Liu
- College of Life Sciences, Institute of Life Sciences and Green Development, Hebei University, Baoding 071002, China
| | - Zhenzhen Yan
- College of Life Sciences, Institute of Life Sciences and Green Development, Hebei University, Baoding 071002, China
| | - Xiaochun Yu
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou 310024, China
- School of Life Sciences, Westlake University, Hangzhou 310024, China
- Institute of Biology, Westlake Institute for Advanced Study, Hangzhou 310024, China
| | - Chen Wu
- College of Life Sciences, Institute of Life Sciences and Green Development, Hebei University, Baoding 071002, China
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Bapat O, Purimetla T, Kruessel S, Shah M, Fan R, Thum C, Rupprecht F, Langer JD, Rangaraju V. VAP spatially stabilizes dendritic mitochondria to locally support synaptic plasticity. Nat Commun 2024; 15:205. [PMID: 38177103 PMCID: PMC10766606 DOI: 10.1038/s41467-023-44233-8] [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: 02/06/2023] [Accepted: 12/05/2023] [Indexed: 01/06/2024] Open
Abstract
Synapses are pivotal sites of plasticity and memory formation. Consequently, synapses are energy consumption hotspots susceptible to dysfunction when their energy supplies are perturbed. Mitochondria are stabilized near synapses via the cytoskeleton and provide the local energy required for synaptic plasticity. However, the mechanisms that tether and stabilize mitochondria to support synaptic plasticity are unknown. We identified proteins exclusively tethering mitochondria to actin near postsynaptic spines. We find that VAP, the vesicle-associated membrane protein-associated protein implicated in amyotrophic lateral sclerosis, stabilizes mitochondria via actin near the spines. To test if the VAP-dependent stable mitochondrial compartments can locally support synaptic plasticity, we used two-photon glutamate uncaging for spine plasticity induction and investigated the induced and adjacent uninduced spines. We find VAP functions as a spatial stabilizer of mitochondrial compartments for up to ~60 min and as a spatial ruler determining the ~30 μm dendritic segment supported during synaptic plasticity.
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Affiliation(s)
- Ojasee Bapat
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
- International Max Planck Research School for Synapses and Circuits, Jupiter, FL, 33458, USA
| | - Tejas Purimetla
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
- Geisel School of Medicine at Dartmouth, Hanover, NH, 03755-1404, USA
| | - Sarah Kruessel
- Max Planck Institute for Brain Research, Frankfurt, 60438, Germany
- Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Monil Shah
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
- International Max Planck Research School for Synapses and Circuits, Jupiter, FL, 33458, USA
| | - Ruolin Fan
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
| | - Christina Thum
- Max Planck Institute for Brain Research, Frankfurt, 60438, Germany
| | - Fiona Rupprecht
- Max Planck Institute for Brain Research, Frankfurt, 60438, Germany
- Max Planck Institute of Biophysics, Frankfurt, 60438, Germany
- Thermo Fisher Diagnostics GmbH, Henningsdorf, 16761, Germany
| | - Julian D Langer
- Max Planck Institute for Brain Research, Frankfurt, 60438, Germany
- Max Planck Institute of Biophysics, Frankfurt, 60438, Germany
| | - Vidhya Rangaraju
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA.
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Weiner S, Sauer M, Brinkmalm G, Constantinescu J, Constantinescu R, Gomes BF, Becker B, Nellgård B, Dalla K, Galasko D, Zetterberg H, Blennow K, Gobom J. SCRN1: A cerebrospinal fluid biomarker correlating with tau in Alzheimer's disease. Alzheimers Dement 2023; 19:4609-4618. [PMID: 36946611 DOI: 10.1002/alz.13042] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/29/2022] [Accepted: 01/04/2023] [Indexed: 03/23/2023]
Abstract
INTRODUCTION Secernin-1 (SCRN1) is a neuronal protein that co-localizes with neurofibrillary tangles in Alzheimer's disease (AD), but not with tau inclusions in corticobasal degeneration (CBD), progressive supranuclear palsy (PSP), or Pick's disease. METHODS We measured SCRN1 concentration in cerebrospinal fluid (CSF) using a novel mass spectrometric parallel reaction monitoring method in three clinical cohorts comprising patients with neurochemically characterized AD (n = 25) and controls (n = 28), clinically diagnosed Parkinson's disease (PD; n = 38), multiple system atrophy (MSA; n = 31), PSP (n = 20), CBD (n = 8), healthy controls (n = 37), and neuropathology-confirmed AD (n = 47). RESULTS CSF SCRN1 was significantly increased in AD (P < 0.01, fold change = 1.4) compared to controls (receiver operating characteristic area under the curve = 0.78) but not in CBD, PSP, PD, or MSA. CSF SCRN1 positively correlated with CSF total tau (R = 0.78, P = 1.1 × 10-13 ), phosphorylated tau181 (R = 0.64, P = 3.2 × 10-8 ), and Braak stage and negatively correlated with Mini-Mental State Examination score. DISCUSSION CSF SCRN1 is a candidate biomarker of AD, reflecting tau pathology. HIGHLIGHTS We developed a parallel reaction monitoring assay to measure secernin-1 (SCRN1) in cerebrospinal fluid (CSF). CSF SCRN1 was increased in Alzheimer's disease compared to healthy controls. CSF SCRN1 remained unchanged in Parkinson's disease, multiple system atrophy, progressive supranuclear palsy, or corticobasal degeneration compared to controls. CSF SCRN1 correlated strongly with CSF phosphorylated tau and total tau. CSF SCRN1 increased across Braak stages and negatively correlated with Mini-Mental State Examination score.
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Affiliation(s)
- Sophia Weiner
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, University of Gothenburg, Mölndal, Sweden
| | - Mathias Sauer
- Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Gunnar Brinkmalm
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, University of Gothenburg, Mölndal, Sweden
| | - Julius Constantinescu
- Department of Neurology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Radu Constantinescu
- Department of Neurology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Bárbara Fernandes Gomes
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, University of Gothenburg, Mölndal, Sweden
| | - Bruno Becker
- Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Bengt Nellgård
- Department of Anesthesiology and Intensive Care Medicine, Institute of Clinical Sciences, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Keti Dalla
- Department of Anesthesiology and Intensive Care Medicine, Institute of Clinical Sciences, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Douglas Galasko
- Department of Neurosciences, University of California, San Diego, La Jolla, California, USA
| | - Henrik Zetterberg
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, Sahlgrenska University Hospital, Mölndal, Sweden
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, UK
- UK Dementia Research Institute, London, UK
- Hong Kong Center for Neurodegenerative Diseases, Hong Kong, China
| | - Kaj Blennow
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Johan Gobom
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, Sahlgrenska University Hospital, Mölndal, Sweden
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Pérez-Moreno JJ, Smith RC, Oliva MK, Gallo F, Ojha S, Müller KH, O’Kane CJ. Drosophila SPG12 ortholog, reticulon-like 1, governs presynaptic ER organization and Ca2+ dynamics. J Cell Biol 2023; 222:e202112101. [PMID: 36952540 PMCID: PMC10072275 DOI: 10.1083/jcb.202112101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/01/2023] [Accepted: 02/24/2023] [Indexed: 03/25/2023] Open
Abstract
Neuronal endoplasmic reticulum (ER) appears continuous throughout the cell. Its shape and continuity are influenced by ER-shaping proteins, mutations in which can cause distal axon degeneration in Hereditary Spastic Paraplegia (HSP). We therefore asked how loss of Rtnl1, a Drosophila ortholog of the human HSP gene RTN2 (SPG12), which encodes an ER-shaping protein, affects ER organization and the function of presynaptic terminals. Loss of Rtnl1 depleted ER membrane markers at Drosophila presynaptic motor terminals and appeared to deplete narrow tubular ER while leaving cisternae largely unaffected, thus suggesting little change in resting Ca2+ storage capacity. Nevertheless, these changes were accompanied by major reductions in activity-evoked Ca2+ fluxes in the cytosol, ER lumen, and mitochondria, as well as reduced evoked and spontaneous neurotransmission. We found that reduced STIM-mediated ER-plasma membrane contacts underlie presynaptic Ca2+ defects in Rtnl1 mutants. Our results show the importance of ER architecture in presynaptic physiology and function, which are therefore potential factors in the pathology of HSP.
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Affiliation(s)
| | | | - Megan K. Oliva
- Department of Genetics, University of Cambridge, Cambridge, UK
| | - Filomena Gallo
- Development and Neuroscience, Cambridge Advanced Imaging Centre, Cambridge, UK
| | - Shainy Ojha
- Department of Genetics, University of Cambridge, Cambridge, UK
| | - Karin H. Müller
- Development and Neuroscience, Cambridge Advanced Imaging Centre, Cambridge, UK
| | - Cahir J. O’Kane
- Department of Genetics, University of Cambridge, Cambridge, UK
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Mackay JP, Smith-Dijak AI, Koch ET, Zhang P, Fung E, Nassrallah WB, Buren C, Schmidt M, Hayden MR, Raymond LA. Axonal ER Ca 2+ Release Selectively Enhances Activity-Independent Glutamate Release in a Huntington Disease Model. J Neurosci 2023; 43:3743-3763. [PMID: 36944490 PMCID: PMC10198457 DOI: 10.1523/jneurosci.1593-22.2023] [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: 08/19/2022] [Revised: 03/08/2023] [Accepted: 03/15/2023] [Indexed: 03/23/2023] Open
Abstract
Action potential (AP)-independent (miniature) neurotransmission occurs at all chemical synapses but remains poorly understood, particularly in pathologic contexts. Axonal endoplasmic reticulum (ER) Ca2+ stores are thought to influence miniature neurotransmission, and aberrant ER Ca2+ handling is implicated in progression of Huntington disease (HD). Here, we report elevated mEPSC frequencies in recordings from YAC128 mouse (HD-model) neurons (from cortical cultures and striatum-containing brain slices, both from male and female animals). Pharmacological experiments suggest that this is mediated indirectly by enhanced tonic ER Ca2+ release. Calcium imaging, using an axon-localized sensor, revealed slow AP-independent ER Ca2+ release waves in both YAC128 and WT cultures. These Ca2+ waves occurred at similar frequencies in both genotypes but spread less extensively and were of lower amplitude in YAC128 axons, consistent with axonal ER Ca2+ store depletion. Surprisingly, basal cytosolic Ca2+ levels were lower in YAC128 boutons and YAC128 mEPSCs were less sensitive to intracellular Ca2+ chelation. Together, these data suggest that elevated miniature glutamate release in YAC128 cultures is associated with axonal ER Ca2+ depletion but not directly mediated by ER Ca2+ release into the cytoplasm. In contrast to increased mEPSC frequencies, cultured YAC128 cortical neurons showed less frequent AP-dependent (spontaneous) Ca2+ events in soma and axons, although evoked glutamate release detected by an intensity-based glutamate-sensing fluorescence reporter in brain slices was similar between genotypes. Our results indicate that axonal ER dysfunction selectively elevates miniature glutamate release from cortical terminals in HD. This, together with reduced spontaneous cortical neuron firing, may cause a shift from activity-dependent to -independent glutamate release in HD, with potential implications for fidelity and plasticity of cortical excitatory signaling.SIGNIFICANCE STATEMENT Miniature neurotransmitter release persists at all chemical neuronal synapses in the absence of action potential firing but remains poorly understood, particularly in disease states. We show enhanced miniature glutamate release from cortical neurons in the YAC128 mouse Huntington disease model. This effect is mediated by axonal ER Ca2+ store depletion, but is not obviously due to elevated ER-to-cytosol Ca2+ release. Conversely, YAC128 cortical pyramidal neurons fired fewer action potentials and evoked cortical glutamate release was similar between WT an YAC128 preparations, indicating axonal ER depletion selectively enhances miniature glutamate release in YAC128 mice. These results extend our understanding of action potential independent neurotransmission and highlight a potential involvement of elevated miniature glutamate release in Huntington disease pathology.
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Affiliation(s)
- James P Mackay
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health
| | - Amy I Smith-Dijak
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health
- Graduate Program in Neuroscience
| | - Ellen T Koch
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health
- Graduate Program in Neuroscience
| | - Peng Zhang
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health
- Department of Neurosciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106
| | - Evan Fung
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health
| | - Wissam B Nassrallah
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health
- MD/PhD Program
| | - Caodu Buren
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health
- Graduate Program in Neuroscience
| | - Mandi Schmidt
- Graduate Program in Neuroscience
- Centre for Molecular Medicine and Therapeutics, British Columbia Children's Hospital Research Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Michael R Hayden
- Centre for Molecular Medicine and Therapeutics, British Columbia Children's Hospital Research Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Lynn A Raymond
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health
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9
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Axonal Regeneration Mediated by a Novel Axonal Guidance Pair, Galectin-1 and Secernin-1. Mol Neurobiol 2023; 60:1250-1266. [PMID: 36437381 DOI: 10.1007/s12035-022-03125-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 11/04/2022] [Indexed: 11/29/2022]
Abstract
Galectin-1 (Gal-1), a member of the Galectin family, is expressed in various tissues and responsible for multiple biological activities. Previous studies reported that extracellular Gal-1 participated in axonal growth and repair, and Gal-1 knockout mice exhibited memory impairment. However, no study has demonstrated the direct contribution of intracellular Gal-1 upregulation in neurons to promoting axonal regeneration in the brain and recovering memory function. In the present study, we found that axonal growth is promoted by overexpression of Gal-1 via adeno-associated virus serotype 9 delivery in primary cultured hippocampal neurons. Moreover, Gal-1 was expressed on the membranes of growth cones in hippocampal neurons and interacted with a novel axonal guidance molecule, Secernin-1, which was secreted from prefrontal cortex (PFC) neurons. Gal-1-overexpression-driven axonal growth was enhanced when recombinant (extracellular) Secernin-1 was treated to the axonal site in a neuron device chamber. Direct binding of extracellular Secernin-1 with Gal-1 was detected through immunoprecipitation and immunocytochemistry, demonstrating that Gal-1 possibly works as an axonal guidance receptor for Secernin-1 in hippocampal neurons. In the PFC, the expression of Gal-1 in axonal shafts and terminals of hippocampal neurons was decreased in the 5XFAD mouse model of Alzheimer's disease (AD). Overexpression of Gal-1 in hippocampal neurons recovered memory deficits and induced axonal regeneration toward the PFC in 5XFAD mice. This study suggests that the enhanced interaction of Secernin-1 and Gal-1 can be harnessed as a therapeutic strategy for long-distance and direction-specific axonal regeneration in AD.
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10
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Yperman K, Kuijpers M. Neuronal endoplasmic reticulum architecture and roles in axonal physiology. Mol Cell Neurosci 2023; 125:103822. [PMID: 36781033 DOI: 10.1016/j.mcn.2023.103822] [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: 11/17/2022] [Revised: 02/06/2023] [Accepted: 02/08/2023] [Indexed: 02/13/2023] Open
Abstract
The endoplasmic reticulum (ER) is the largest membrane compartment within eukaryotic cells and is emerging as a key coordinator of many cellular processes. The ER can modulate local calcium fluxes and communicate with other organelles like the plasma membrane. The importance of ER in neuronal processes such as neurite growth, axon repair and neurotransmission has recently gained much attention. In this review, we highlight the importance of the ER tubular network in axonal homeostasis and discuss how the generation and maintenance of the thin tubular ER network in axons and synapses, requires a cooperative effort of ER-shaping proteins, cytoskeleton and autophagy processes.
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Affiliation(s)
- Klaas Yperman
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - Marijn Kuijpers
- Department of Molecular Neurobiology, Donders Institute for Brain, Cognition and Behaviour and Faculty of Science, Radboud University, 6525 AJ Nijmegen, the Netherlands.
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11
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Activity-dependent endoplasmic reticulum Ca 2+ uptake depends on Kv2.1-mediated endoplasmic reticulum/plasma membrane junctions to promote synaptic transmission. Proc Natl Acad Sci U S A 2022; 119:e2117135119. [PMID: 35862456 PMCID: PMC9335237 DOI: 10.1073/pnas.2117135119] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The endoplasmic reticulum (ER) extends throughout the neuron as a continuous organelle, and its dysfunction is associated with several neurological disorders. During electrical activity, the ER takes up Ca2+ from the cytosol, which has been shown to support synaptic transmission. This close choreography of ER Ca2+ uptake with electrical activity suggests functional coupling of the ER to sources of voltage-gated Ca2+ entry through an unknown mechanism. We report that a nonconducting role for Kv2.1 through its ER binding domain is necessary for ER Ca2+ uptake during neuronal activity. Loss of Kv2.1 profoundly disables neurotransmitter release without altering presynaptic voltage. This suggests that Kv2.1-mediated signaling hubs play an important neurobiological role in Ca2+ handling and synaptic transmission independent of ion conduction. The endoplasmic reticulum (ER) forms a continuous and dynamic network throughout a neuron, extending from dendrites to axon terminals, and axonal ER dysfunction is implicated in several neurological disorders. In addition, tight junctions between the ER and plasma membrane (PM) are formed by several molecules including Kv2 channels, but the cellular functions of many ER-PM junctions remain unknown. Recently, dynamic Ca2+ uptake into the ER during electrical activity was shown to play an essential role in synaptic transmission. Our experiments demonstrate that Kv2.1 channels are necessary for enabling ER Ca2+ uptake during electrical activity, as knockdown (KD) of Kv2.1 rendered both the somatic and axonal ER unable to accumulate Ca2+ during electrical stimulation. Moreover, our experiments demonstrate that the loss of Kv2.1 in the axon impairs synaptic vesicle fusion during stimulation via a mechanism unrelated to voltage. Thus, our data demonstrate that a nonconducting role of Kv2.1 exists through its binding to the ER protein VAMP-associated protein (VAP), which couples ER Ca2+ uptake with electrical activity. Our results further suggest that Kv2.1 has a critical function in neuronal cell biology for Ca2+ handling independent of voltage and reveals a critical pathway for maintaining ER lumen Ca2+ levels and efficient neurotransmitter release. Taken together, these findings reveal an essential nonclassical role for both Kv2.1 and the ER-PM junctions in synaptic transmission.
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12
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Khan S. Endoplasmic Reticulum in Metaplasticity: From Information Processing to Synaptic Proteostasis. Mol Neurobiol 2022; 59:5630-5655. [PMID: 35739409 DOI: 10.1007/s12035-022-02916-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 06/05/2022] [Indexed: 11/29/2022]
Abstract
The ER (endoplasmic reticulum) is a Ca2+ reservoir and the unique protein-synthesizing machinery which is distributed throughout the neuron and composed of multiple different structural domains. One such domain is called EMC (endoplasmic reticulum membrane protein complex), pleiotropic nature in cellular functions. The ER/EMC position inside the neurons unmasks its contribution to synaptic plasticity via regulating various cellular processes from protein synthesis to Ca2+ signaling. Since presynaptic Ca2+ channels and postsynaptic ionotropic receptors are organized into the nanodomains, thus ER can be a crucial player in establishing TMNCs (transsynaptic molecular nanocolumns) to shape efficient neural communications. This review hypothesized that ER is not only involved in stress-mediated neurodegeneration but also axon regrowth, remyelination, neurotransmitter switching, information processing, and regulation of pre- and post-synaptic functions. Thus ER might not only be a protein-synthesizing and quality control machinery but also orchestrates plasticity of plasticity (metaplasticity) within the neuron to execute higher-order brain functions and neural repair.
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Affiliation(s)
- Shumsuzzaman Khan
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, USA.
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13
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Deng C, Reinhard S, Hennlein L, Eilts J, Sachs S, Doose S, Jablonka S, Sauer M, Moradi M, Sendtner M. Impaired dynamic interaction of axonal endoplasmic reticulum and ribosomes contributes to defective stimulus-response in spinal muscular atrophy. Transl Neurodegener 2022; 11:31. [PMID: 35650592 PMCID: PMC9161492 DOI: 10.1186/s40035-022-00304-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 04/28/2022] [Indexed: 11/19/2022] Open
Abstract
Background Axonal degeneration and defects in neuromuscular neurotransmission represent a pathological hallmark in spinal muscular atrophy (SMA) and other forms of motoneuron disease. These pathological changes do not only base on altered axonal and presynaptic architecture, but also on alterations in dynamic movements of organelles and subcellular structures that are not necessarily reflected by static histopathological changes. The dynamic interplay between the axonal endoplasmic reticulum (ER) and ribosomes is essential for stimulus-induced local translation in motor axons and presynaptic terminals. However, it remains enigmatic whether the ER and ribosome crosstalk is impaired in the presynaptic compartment of motoneurons with Smn (survival of motor neuron) deficiency that could contribute to axonopathy and presynaptic dysfunction in SMA. Methods Using super-resolution microscopy, proximity ligation assay (PLA) and live imaging of cultured motoneurons from a mouse model of SMA, we investigated the dynamics of the axonal ER and ribosome distribution and activation. Results We observed that the dynamic remodeling of ER was impaired in axon terminals of Smn-deficient motoneurons. In addition, in axon terminals of Smn-deficient motoneurons, ribosomes failed to respond to the brain-derived neurotrophic factor stimulation, and did not undergo rapid association with the axonal ER in response to extracellular stimuli. Conclusions These findings implicate impaired dynamic interplay between the ribosomes and ER in axon terminals of motoneurons as a contributor to the pathophysiology of SMA and possibly also other motoneuron diseases. Supplementary Information The online version contains supplementary material available at 10.1186/s40035-022-00304-2.
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Affiliation(s)
- Chunchu Deng
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, 97078, Würzburg, Germany
| | - Sebastian Reinhard
- Department of Biotechnology and Biophysics, Biocenter, Julius-Maximilians-University Wuerzburg, 97074, Würzburg, Germany
| | - Luisa Hennlein
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, 97078, Würzburg, Germany
| | - Janna Eilts
- Department of Biotechnology and Biophysics, Biocenter, Julius-Maximilians-University Wuerzburg, 97074, Würzburg, Germany
| | - Stefan Sachs
- Department of Biotechnology and Biophysics, Biocenter, Julius-Maximilians-University Wuerzburg, 97074, Würzburg, Germany
| | - Sören Doose
- Department of Biotechnology and Biophysics, Biocenter, Julius-Maximilians-University Wuerzburg, 97074, Würzburg, Germany
| | - Sibylle Jablonka
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, 97078, Würzburg, Germany
| | - Markus Sauer
- Department of Biotechnology and Biophysics, Biocenter, Julius-Maximilians-University Wuerzburg, 97074, Würzburg, Germany
| | - Mehri Moradi
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, 97078, Würzburg, Germany.
| | - Michael Sendtner
- Institute of Clinical Neurobiology, University Hospital Wuerzburg, 97078, Würzburg, Germany.
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14
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Peppercorn K, Kleffmann T, Jones O, Hughes S, Tate W. Secreted Amyloid Precursor Protein Alpha, a Neuroprotective Protein in the Brain Has Widespread Effects on the Transcriptome and Proteome of Human Inducible Pluripotent Stem Cell-Derived Glutamatergic Neurons Related to Memory Mechanisms. Front Neurosci 2022; 16:858524. [PMID: 35692428 PMCID: PMC9179159 DOI: 10.3389/fnins.2022.858524] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 03/14/2022] [Indexed: 11/18/2022] Open
Abstract
Secreted amyloid precursor protein alpha (sAPPα) processed from a parent human brain protein, APP, can modulate learning and memory. It has potential for development as a therapy preventing, delaying, or even reversing Alzheimer’s disease. In this study a comprehensive analysis to understand how it affects the transcriptome and proteome of the human neuron was undertaken. Human inducible pluripotent stem cell (iPSC)-derived glutamatergic neurons in culture were exposed to 1 nM sAPPα over a time course and changes in the transcriptome and proteome were identified with RNA sequencing and Sequential Window Acquisition of All THeoretical Fragment Ion Spectra-Mass Spectrometry (SWATH-MS), respectively. A large subset (∼30%) of differentially expressed transcripts and proteins were functionally involved with the molecular biology of learning and memory, consistent with reported links of sAPPα to memory enhancement, as well as neurogenic, neurotrophic, and neuroprotective phenotypes in previous studies. Differentially regulated proteins included those encoded in previously identified Alzheimer’s risk genes, APP processing related proteins, proteins involved in synaptogenesis, neurotransmitters, receptors, synaptic vesicle proteins, cytoskeletal proteins, proteins involved in protein and organelle trafficking, and proteins important for cell signalling, transcriptional splicing, and functions of the proteasome and lysosome. We have identified a complex set of genes affected by sAPPα, which may aid further investigation into the mechanism of how this neuroprotective protein affects memory formation and how it might be used as an Alzheimer’s disease therapy.
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Affiliation(s)
- Katie Peppercorn
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
- Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Torsten Kleffmann
- Division of Health Sciences, Research Infrastructure Centre, University of Otago, Dunedin, New Zealand
| | - Owen Jones
- Brain Health Research Centre, University of Otago, Dunedin, New Zealand
- Department of Psychology, University of Otago, Dunedin, New Zealand
| | - Stephanie Hughes
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
- Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Warren Tate
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
- Brain Health Research Centre, University of Otago, Dunedin, New Zealand
- *Correspondence: Warren Tate,
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15
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Zamponi E, Meehl JB, Voeltz GK. The ER ladder is a unique morphological feature of developing mammalian axons. Dev Cell 2022; 57:1369-1382.e6. [PMID: 35609616 DOI: 10.1016/j.devcel.2022.05.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 03/28/2022] [Accepted: 05/02/2022] [Indexed: 11/25/2022]
Abstract
The endoplasmic reticulum (ER) confronts a challenge to accommodate long, smooth ER tubules into the structural complexity of the axonal compartment. Here, we describe a morphological feature for the axonal ER network in developing neurons we termed the ER ladder. Axonal ER ladders are composed of rungs that wrap tightly around the microtubule bundle and dynamic rails, which slide across microtubules. We found that the ER-shaping protein Reticulon 2 determines the architecture and dynamics of the axonal ER ladder by modulating its interaction with microtubules. Moreover, we show that ER ladder depletion impairs the trafficking of associated vesicular axonal cargoes. Finally, we demonstrate that stromal interaction molecule 1 (Stim1) localizes to ER rungs and translocates to ER-plasma membrane contact sites upon depletion of luminal Ca2+. Our findings uncover fundamental insights into the structural and functional organization of the axonal ER network in developing mammalian neurons.
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Affiliation(s)
- Emiliano Zamponi
- Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, Boulder, CO 80309, USA; Howard Hughes Medical Institute, Boulder, CO 80309, USA
| | - Janet B Meehl
- Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, Boulder, CO 80309, USA; Howard Hughes Medical Institute, Boulder, CO 80309, USA
| | - Gia K Voeltz
- Department of Molecular, Cellular & Developmental Biology, University of Colorado Boulder, Boulder, CO 80309, USA; Howard Hughes Medical Institute, Boulder, CO 80309, USA.
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16
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Linhorst A, Lübke T. The Human Ntn-Hydrolase Superfamily: Structure, Functions and Perspectives. Cells 2022; 11:cells11101592. [PMID: 35626629 PMCID: PMC9140057 DOI: 10.3390/cells11101592] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 05/05/2022] [Accepted: 05/06/2022] [Indexed: 01/27/2023] Open
Abstract
N-terminal nucleophile (Ntn)-hydrolases catalyze the cleavage of amide bonds in a variety of macromolecules, including the peptide bond in proteins, the amide bond in N-linked protein glycosylation, and the amide bond linking a fatty acid to sphingosine in complex sphingolipids. Ntn-hydrolases are all sharing two common hallmarks: Firstly, the enzymes are synthesized as inactive precursors that undergo auto-proteolytic self-activation, which, as a consequence, reveals the active site nucleophile at the newly formed N-terminus. Secondly, all Ntn-hydrolases share a structural consistent αββα-fold, notwithstanding the total lack of amino acid sequence homology. In humans, five subclasses of the Ntn-superfamily have been identified so far, comprising relevant members such as the catalytic active subunits of the proteasome or a number of lysosomal hydrolases, which are often associated with lysosomal storage diseases. This review gives an updated overview on the structural, functional, and (patho-)physiological characteristics of human Ntn-hydrolases, in particular.
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17
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Chanaday NL, Kavalali ET. Role of the endoplasmic reticulum in synaptic transmission. Curr Opin Neurobiol 2022; 73:102538. [PMID: 35395547 PMCID: PMC9167765 DOI: 10.1016/j.conb.2022.102538] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 02/25/2022] [Accepted: 03/06/2022] [Indexed: 11/03/2022]
Abstract
Neurons possess a complex morphology spanning long distances and a large number of subcellular specializations such as presynaptic terminals and dendritic spines. This structural complexity is essential for maintenance of synaptic junctions and associated electrical as well as biochemical signaling events. Given the structural and functional complexity of neurons, neuronal endoplasmic reticulum is emerging as a key regulator of neuronal function, in particular synaptic signaling. Neuronal endoplasmic reticulum mediates calcium signaling, calcium and lipid homeostasis, vesicular trafficking, and proteostasis events that underlie autonomous functions of numerous subcellular compartments. However, based on its geometric complexity spanning the whole neuron, endoplasmic reticulum also integrates the activity of these autonomous compartments across the neuron and coordinates their interactions with the soma. In this article, we review recent work regarding neuronal endoplasmic reticulum function and its relationship to neurotransmission and plasticity.
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Affiliation(s)
- Natali L Chanaday
- Department of Pharmacology, School of Medicine, Vanderbilt University, Nashville, TN, 37240-7933, USA.
| | - Ege T Kavalali
- Department of Pharmacology, School of Medicine, Vanderbilt University, Nashville, TN, 37240-7933, USA; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, 37240-7933, USA.
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18
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Tendulkar S, Hegde S, Garg L, Thulasidharan A, Kaduskar B, Ratnaparkhi A, Ratnaparkhi GS. Caspar, an adapter for VAPB and TER94, modulates the progression of ALS8 by regulating IMD/NFκB mediated glial inflammation in a drosophila model of human disease. Hum Mol Genet 2022; 31:2857-2875. [PMID: 35377453 PMCID: PMC9433731 DOI: 10.1093/hmg/ddac076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 03/25/2022] [Accepted: 03/29/2022] [Indexed: 11/16/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal, late-onset, progressive motor neurodegenerative disorder. A key pathological feature of the disease is the presence of heavily ubiquitinated protein inclusions. Both the unfolded protein response and the ubiquitin–proteasome system appear significantly impaired in patients and animal models of ALS. We have studied cellular and molecular mechanisms involved in ALS using a vesicle-associated membrane protein-associated protein B (VAPB/ALS8) Drosophila model [Moustaqim-Barrette, A., Lin, Y.Q., Pradhan, S., Neely, G.G., Bellen, H.J. and Tsuda, H. (2014) The ALS 8 protein, VAP, is required for ER protein quality control. Hum. Mol. Genet., 23, 1975–1989], which mimics many systemic aspects of the human disease. Here, we show that VAPB, located on the cytoplasmic face of the endoplasmic reticulum membrane, interacts with Caspar, an orthologue of human fas associated factor 1 (FAF1). Caspar, in turn, interacts with transitional endoplasmic reticulum ATPase (TER94), a fly orthologue of ALS14 (VCP/p97, valosin-containing protein). Caspar overexpression in the glia extends lifespan and also slows the progression of motor dysfunction in the ALS8 disease model, a phenomenon that we ascribe to its ability to restrain age-dependent inflammation, which is modulated by Relish/NFκB signalling. Caspar binds to VAPB via an FFAT motif, and we find that Caspar’s ability to negatively regulate NFκB signalling is not dependent on the VAPB:Caspar interaction. We hypothesize that Caspar is a key molecule in the pathogenesis of ALS. The VAPB:Caspar:TER94 complex appears to be a candidate for regulating both protein homeostasis and NFκB signalling, with our study highlighting a role for Caspar in glial inflammation. We project human FAF1 as an important protein target to alleviate the progression of motor neuron disease.
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Affiliation(s)
- Shweta Tendulkar
- Indian Institute of Science Education & Research (IISER) Pune 411008, India
| | - Sushmitha Hegde
- Indian Institute of Science Education & Research (IISER) Pune 411008, India
| | - Lovleen Garg
- Indian Institute of Science Education & Research (IISER) Pune 411008, India
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19
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Wang X, Lin Z, Bustin KA, McKnight NR, Parsons WH, Matthews ML. Discovery of Potent and Selective Inhibitors against Protein-Derived Electrophilic Cofactors. J Am Chem Soc 2022; 144:5377-5388. [PMID: 35235319 PMCID: PMC10159212 DOI: 10.1021/jacs.1c12748] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Electrophilic cofactors are widely distributed in nature and play important roles in many physiological and disease processes, yet they have remained blind spots in traditional activity-based protein profiling (ABPP) approaches that target nucleophiles. More recently, reverse-polarity (RP)-ABPP using hydrazine probes identified an electrophilic N-terminal glyoxylyl (Glox) group for the first time in secernin-3 (SCRN3). The biological function(s) of both the protein and Glox as a cofactor has not yet been pharmacologically validated because of the lack of selective inhibitors that could disrupt and therefore identify its activity. Here, we present the first platform for analyzing the reactivity and selectivity of an expanded nucleophilic probe library toward main-chain carbonyl cofactors such as Glox and pyruvoyl (Pyvl) groups. We first applied the library proteome-wide to profile and confirm engagement with various electrophilic protein targets, including secernin-2 (SCRN2), shown here also to possess a Glox group. A broadly reactive indole ethylhydrazine probe was used for a competitive in vitro RP-ABPP assay to screen for selective inhibitors against such cofactors from a set of commercially available nucleophilic fragments. Using Glox-containing SCRN proteins as a case study, naphthyl hydrazine was identified as a potent and selective SCRN3 inhibitor, showing complete inhibition in cell lysates with no significant cross-reactivity detected for other enzymes. Moving forward, this platform provides the fundamental basis for the development of selective Glox inhibitors and represents a starting point to advance small molecules that modulate electrophile-dependent function.
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Affiliation(s)
- Xie Wang
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Zongtao Lin
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Katelyn A Bustin
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Nate R McKnight
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - William H Parsons
- Department of Chemistry and Biochemistry, Oberlin College, Oberlin, Ohio 44074, United States
| | - Megan L Matthews
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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20
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Kors S, Costello JL, Schrader M. VAP Proteins - From Organelle Tethers to Pathogenic Host Interactors and Their Role in Neuronal Disease. Front Cell Dev Biol 2022; 10:895856. [PMID: 35756994 PMCID: PMC9213790 DOI: 10.3389/fcell.2022.895856] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 04/25/2022] [Indexed: 12/26/2022] Open
Abstract
Vesicle-associated membrane protein (VAMP)-associated proteins (VAPs) are ubiquitous ER-resident tail-anchored membrane proteins in eukaryotic cells. Their N-terminal major sperm protein (MSP) domain faces the cytosol and allows them to interact with a wide variety of cellular proteins. Therefore, VAP proteins are vital to many cellular processes, including organelle membrane tethering, lipid transfer, autophagy, ion homeostasis and viral defence. Here, we provide a timely overview of the increasing number of VAPA/B binding partners and discuss the role of VAPA/B in maintaining organelle-ER interactions and cooperation. Furthermore, we address how viruses and intracellular bacteria hijack VAPs and their binding partners to induce interactions between the host ER and pathogen-containing compartments and support pathogen replication. Finally, we focus on the role of VAP in human disease and discuss how mutated VAPB leads to the disruption of cellular homeostasis and causes amyotrophic lateral sclerosis.
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Affiliation(s)
- Suzan Kors
- *Correspondence: Suzan Kors, ; Michael Schrader,
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21
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Deng C, Moradi M, Reinhard S, Ji C, Jablonka S, Hennlein L, Lüningschrör P, Doose S, Sauer M, Sendtner M. Dynamic remodeling of ribosomes and endoplasmic reticulum in axon terminals of motoneurons. J Cell Sci 2021; 134:272552. [PMID: 34668554 DOI: 10.1242/jcs.258785] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 10/14/2021] [Indexed: 12/23/2022] Open
Abstract
In neurons, the endoplasmic reticulum (ER) forms a highly dynamic network that enters axons and presynaptic terminals and plays a central role in Ca2+ homeostasis and synapse maintenance; however, the underlying mechanisms involved in regulation of its dynamic remodeling as well as its function in axon development and presynaptic differentiation remain elusive. Here, we used high-resolution microscopy and live-cell imaging to investigate rapid movements of the ER and ribosomes in axons of cultured motoneurons after stimulation with brain-derived neurotrophic factor. Our results indicate that the ER extends into axonal growth cone filopodia, where its integrity and dynamic remodeling are regulated mainly by actin and the actin-based motor protein myosin VI (encoded by Myo6). Additionally, we found that in axonal growth cones, ribosomes assemble into 80S subunits within seconds and associate with the ER in response to extracellular stimuli, which describes a novel function of axonal ER in dynamic regulation of local translation. This article has an associated First Person interview with Chunchu Deng, joint first author of the paper.
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Affiliation(s)
- Chunchu Deng
- Institute of Clinical Neurobiology, University Hospital Würzburg, 97078 Würzburg, Germany
| | - Mehri Moradi
- Institute of Clinical Neurobiology, University Hospital Würzburg, 97078 Würzburg, Germany
| | - Sebastian Reinhard
- Department of Biotechnology and Biophysics, Biocenter, Julius-Maximilians-University Würzburg, 97074 Würzburg, Germany
| | - Changhe Ji
- Institute of Clinical Neurobiology, University Hospital Würzburg, 97078 Würzburg, Germany
| | - Sibylle Jablonka
- Institute of Clinical Neurobiology, University Hospital Würzburg, 97078 Würzburg, Germany
| | - Luisa Hennlein
- Institute of Clinical Neurobiology, University Hospital Würzburg, 97078 Würzburg, Germany
| | - Patrick Lüningschrör
- Institute of Clinical Neurobiology, University Hospital Würzburg, 97078 Würzburg, Germany
| | - Sören Doose
- Department of Biotechnology and Biophysics, Biocenter, Julius-Maximilians-University Würzburg, 97074 Würzburg, Germany
| | - Markus Sauer
- Department of Biotechnology and Biophysics, Biocenter, Julius-Maximilians-University Würzburg, 97074 Würzburg, Germany
| | - Michael Sendtner
- Institute of Clinical Neurobiology, University Hospital Würzburg, 97078 Würzburg, Germany
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22
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Borgese N, Iacomino N, Colombo SF, Navone F. The Link between VAPB Loss of Function and Amyotrophic Lateral Sclerosis. Cells 2021; 10:1865. [PMID: 34440634 PMCID: PMC8392409 DOI: 10.3390/cells10081865] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/16/2021] [Accepted: 07/16/2021] [Indexed: 02/06/2023] Open
Abstract
The VAP proteins are integral adaptor proteins of the endoplasmic reticulum (ER) membrane that recruit a myriad of interacting partners to the ER surface. Through these interactions, the VAPs mediate a large number of processes, notably the generation of membrane contact sites between the ER and essentially all other cellular membranes. In 2004, it was discovered that a mutation (p.P56S) in the VAPB paralogue causes a rare form of dominantly inherited familial amyotrophic lateral sclerosis (ALS8). The mutant protein is aggregation-prone, non-functional and unstable, and its expression from a single allele appears to be insufficient to support toxic gain-of-function effects within motor neurons. Instead, loss-of-function of the single wild-type allele is required for pathological effects, and VAPB haploinsufficiency may be the main driver of the disease. In this article, we review the studies on the effects of VAPB deficit in cellular and animal models. Several basic cell physiological processes are affected by downregulation or complete depletion of VAPB, impinging on phosphoinositide homeostasis, Ca2+ signalling, ion transport, neurite extension, and ER stress. In the future, the distinction between the roles of the two VAP paralogues (A and B), as well as studies on motor neurons generated from induced pluripotent stem cells (iPSC) of ALS8 patients will further elucidate the pathogenic basis of p.P56S familial ALS, as well as of other more common forms of the disease.
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Affiliation(s)
- Nica Borgese
- CNR Institute of Neuroscience, Via Follereau 3, Bldg U28, 20854 Vedano al Lambro, Italy; (N.I.); (S.F.C.)
| | | | | | - Francesca Navone
- CNR Institute of Neuroscience, Via Follereau 3, Bldg U28, 20854 Vedano al Lambro, Italy; (N.I.); (S.F.C.)
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23
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Özkan N, Koppers M, van Soest I, van Harten A, Jurriens D, Liv N, Klumperman J, Kapitein LC, Hoogenraad CC, Farías GG. ER - lysosome contacts at a pre-axonal region regulate axonal lysosome availability. Nat Commun 2021; 12:4493. [PMID: 34301956 PMCID: PMC8302662 DOI: 10.1038/s41467-021-24713-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 07/01/2021] [Indexed: 11/16/2022] Open
Abstract
Neuronal function relies on careful coordination of organelle organization and transport. Kinesin-1 mediates transport of the endoplasmic reticulum (ER) and lysosomes into the axon and it is increasingly recognized that contacts between the ER and lysosomes influence organelle organization. However, it is unclear how organelle organization, inter-organelle communication and transport are linked and how this contributes to local organelle availability in neurons. Here, we show that somatic ER tubules are required for proper lysosome transport into the axon. Somatic ER tubule disruption causes accumulation of enlarged and less motile lysosomes at the soma. ER tubules regulate lysosome size and axonal translocation by promoting lysosome homo-fission. ER tubule - lysosome contacts often occur at a somatic pre-axonal region, where the kinesin-1-binding ER-protein P180 binds microtubules to promote kinesin-1-powered lysosome fission and subsequent axonal translocation. We propose that ER tubule - lysosome contacts at a pre-axonal region finely orchestrate axonal lysosome availability for proper neuronal function.
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Affiliation(s)
- Nazmiye Özkan
- Cell Biology, Neurobiology and Biophysics. Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Max Koppers
- Cell Biology, Neurobiology and Biophysics. Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Inge van Soest
- Cell Biology, Neurobiology and Biophysics. Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Alexandra van Harten
- Cell Biology, Neurobiology and Biophysics. Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Daphne Jurriens
- Cell Biology, Neurobiology and Biophysics. Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Nalan Liv
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Judith Klumperman
- Section Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Lukas C Kapitein
- Cell Biology, Neurobiology and Biophysics. Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Casper C Hoogenraad
- Cell Biology, Neurobiology and Biophysics. Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Ginny G Farías
- Cell Biology, Neurobiology and Biophysics. Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands.
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24
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Neefjes J, Cabukusta B. What the VAP: The Expanded VAP Family of Proteins Interacting With FFAT and FFAT-Related Motifs for Interorganellar Contact. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2021; 4:25152564211012246. [PMID: 34036242 PMCID: PMC7610837 DOI: 10.1177/25152564211012246] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Membrane contact sites are formed by tether proteins that have the ability to bring two organellar membranes together. VAP proteins are a family of endoplasmic reticulum (ER)-resident tether proteins specialized in interacting with FFAT (two phenylalanines in an acidic tract) peptide motifs in other proteins. If the FFAT-motif-containing proteins reside on other organelles, VAP proteins form contact sites between these organelles and the ER. The role of VAPA and VAPB, the two founding members of the VAP family in recruiting proteins to the ER and forming membrane contact sites is well appreciated as numerous interaction partners of VAPA and VAPB at different intracellular contact sites have been characterized. Recently, three new proteins -MOSPD1, MOSPD2 and MOSPD3-have been added to the VAP family. While MOSPD2 has a motif preference similar to VAPA and VAPB, MOSPD1 and MOSPD3 prefer to interact with proteins containing FFNT (two phenylalanines in a neutral tract) motifs. In this review, we discuss the recent advances in motif binding by VAP proteins along with the other biological processes VAP proteins are involved in.
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Affiliation(s)
- Jacques Neefjes
- Cell and Chemical Biology, Oncode Institute, Leiden University Medical Center, Leiden, the Netherlands
| | - Birol Cabukusta
- Cell and Chemical Biology, Oncode Institute, Leiden University Medical Center, Leiden, the Netherlands
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25
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Lindhout FW, Portegies S, Kooistra R, Herstel LJ, Stucchi R, Hummel JJA, Scheefhals N, Katrukha EA, Altelaar M, MacGillavry HD, Wierenga CJ, Hoogenraad CC. Centrosome-mediated microtubule remodeling during axon formation in human iPSC-derived neurons. EMBO J 2021; 40:e106798. [PMID: 33835529 PMCID: PMC8126955 DOI: 10.15252/embj.2020106798] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 02/09/2021] [Accepted: 02/17/2021] [Indexed: 12/21/2022] Open
Abstract
Axon formation critically relies on local microtubule remodeling and marks the first step in establishing neuronal polarity. However, the function of the microtubule‐organizing centrosomes during the onset of axon formation is still under debate. Here, we demonstrate that centrosomes play an essential role in controlling axon formation in human‐induced pluripotent stem cell (iPSC)‐derived neurons. Depleting centrioles, the core components of centrosomes, in unpolarized human neuronal stem cells results in various axon developmental defects at later stages, including immature action potential firing, mislocalization of axonal microtubule‐associated Trim46 proteins, suppressed expression of growth cone proteins, and affected growth cone morphologies. Live‐cell imaging of microtubules reveals that centriole loss impairs axonal microtubule reorganization toward the unique parallel plus‐end out microtubule bundles during early development. We propose that centrosomes mediate microtubule remodeling during early axon development in human iPSC‐derived neurons, thereby laying the foundation for further axon development and function.
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Affiliation(s)
- Feline W Lindhout
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Sybren Portegies
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Robbelien Kooistra
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Lotte J Herstel
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Riccardo Stucchi
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands.,Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Jessica J A Hummel
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Nicky Scheefhals
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Eugene A Katrukha
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Maarten Altelaar
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Harold D MacGillavry
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Corette J Wierenga
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Casper C Hoogenraad
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands.,Department of Neuroscience, Genentech, Inc, South San Francisco, CA, USA
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26
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Axonal Organelles as Molecular Platforms for Axon Growth and Regeneration after Injury. Int J Mol Sci 2021; 22:ijms22041798. [PMID: 33670312 PMCID: PMC7918155 DOI: 10.3390/ijms22041798] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/06/2021] [Accepted: 02/08/2021] [Indexed: 02/06/2023] Open
Abstract
Investigating the molecular mechanisms governing developmental axon growth has been a useful approach for identifying new strategies for boosting axon regeneration after injury, with the goal of treating debilitating conditions such as spinal cord injury and vision loss. The picture emerging is that various axonal organelles are important centers for organizing the molecular mechanisms and machinery required for growth cone development and axon extension, and these have recently been targeted to stimulate robust regeneration in the injured adult central nervous system (CNS). This review summarizes recent literature highlighting a central role for organelles such as recycling endosomes, the endoplasmic reticulum, mitochondria, lysosomes, autophagosomes and the proteasome in developmental axon growth, and describes how these organelles can be targeted to promote axon regeneration after injury to the adult CNS. This review also examines the connections between these organelles in developing and regenerating axons, and finally discusses the molecular mechanisms within the axon that are required for successful axon growth.
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27
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Li C, Qian T, He R, Wan C, Liu Y, Yu H. Endoplasmic Reticulum-Plasma Membrane Contact Sites: Regulators, Mechanisms, and Physiological Functions. Front Cell Dev Biol 2021; 9:627700. [PMID: 33614657 PMCID: PMC7889955 DOI: 10.3389/fcell.2021.627700] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 01/13/2021] [Indexed: 12/13/2022] Open
Abstract
The endoplasmic reticulum (ER) forms direct membrane contact sites with the plasma membrane (PM) in eukaryotic cells. These ER-PM contact sites play essential roles in lipid homeostasis, ion dynamics, and cell signaling, which are carried out by protein-protein or protein-lipid interactions. Distinct tethering factors dynamically control the architecture of ER-PM junctions in response to intracellular signals or external stimuli. The physiological roles of ER-PM contact sites are dependent on a variety of regulators that individually or cooperatively perform functions in diverse cellular processes. This review focuses on proteins functioning at ER-PM contact sites and highlights the recent progress in their mechanisms and physiological roles.
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Affiliation(s)
- Chenlu Li
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Tiantian Qian
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Ruyue He
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Chun Wan
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO, United States
| | - Yinghui Liu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Haijia Yu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
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28
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Houston BJ, Nagirnaja L, Merriner DJ, O'Connor AE, Okuda H, Omurtag K, Smith C, Aston KI, Conrad DF, O'Bryan MK. The Sertoli cell expressed gene secernin-1 (Scrn1) is dispensable for male fertility in the mouse. Dev Dyn 2021; 250:922-931. [PMID: 33442887 DOI: 10.1002/dvdy.299] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 01/05/2021] [Accepted: 01/08/2021] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Male infertility is a prevalent clinical presentation for which there is likely a strong genetic component due to the thousands of genes required for spermatogenesis. Within this study we investigated the role of the gene Scrn1 in male fertility. Scrn1 is preferentially expressed in XY gonads during the period of sex determination and in adult Sertoli cells based on single cell RNA sequencing. We investigated the expression of Scrn1 in juvenile and adult tissues and generated a knockout mouse model to test its role in male fertility. RESULTS Scrn1 was expressed at all ages examined in the post-natal testis; however, its expression peaked at postnatal days 7-14 and SCRN1 protein was clearly localized to Sertoli cells. Scrn1 deletion was achieved via removal of exon 3, and its loss had no effect on male fertility or sex determination. Knockout mice were capable of siring litters of equal size to wild type counterparts and generated equal numbers of sperm with comparable motility and morphology characteristics. CONCLUSIONS Scrn1 was found to be dispensable for male fertility, but this study identifies SCRN1 as a novel marker of the Sertoli cell cytoplasm.
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Affiliation(s)
- Brendan J Houston
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia.,School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Liina Nagirnaja
- Division of Genetics, Oregon National Primate Research Center, Beaverton, Oregon, USA
| | - D Jo Merriner
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
| | - Anne E O'Connor
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
| | - Hidenobu Okuda
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia
| | - Kenan Omurtag
- Division of Reproductive Endocrinology and Infertility, School of Medicine, Washington University, St Louis, Missouri, USA
| | - Craig Smith
- Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Kenneth I Aston
- Department of Surgery (Urology), University of Utah, Salt Lake City, Utah, USA
| | - Donald F Conrad
- Division of Genetics, Oregon National Primate Research Center, Beaverton, Oregon, USA
| | - Moira K O'Bryan
- School of Biological Sciences, Monash University, Clayton, Victoria, Australia.,School of BioSciences, The University of Melbourne, Parkville, Victoria, Australia
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29
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Deregulation of phosphatidylinositol-4-phosphate in the development of amyotrophic lateral sclerosis 8. Adv Biol Regul 2021; 79:100779. [PMID: 33461946 DOI: 10.1016/j.jbior.2020.100779] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 12/15/2020] [Accepted: 12/21/2020] [Indexed: 01/19/2023]
Abstract
Amyotrophic lateral sclerosis 8 (ALS8) is one of a heterogeneous group of progressive neurodegenerative disorders characterized by the death of motor neurons. ALS8 is caused by mutations in VAPB, a protein that acts at multiple membrane contact sites between the endoplasmic reticulum (ER) and almost all other organelles and thus affects functions at diverse cellular locations. One prominent function mediated by VAPB at these sites is lipid exchange, and a recurrent phenotype observed in all models investigating knockout or knockdown of VAPs is a significant increase in the levels of phosphatidylinositol-4-phosphate (PI4P). Here we consider the relevance of this PI4P deregulation in the development of ALS8 that might represent a potential target for therapeutic intervention.
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30
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TSUBOI M, HIRABAYASHI Y. New insights into the regulation of synaptic transmission and plasticity by the endoplasmic reticulum and its membrane contacts. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2021; 97:559-572. [PMID: 34897182 PMCID: PMC8687855 DOI: 10.2183/pjab.97.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 10/18/2021] [Indexed: 06/14/2023]
Abstract
Mammalian neurons are highly compartmentalized yet very large cells. To provide each compartment with its distinct properties, metabolic homeostasis and molecular composition need to be precisely coordinated in a compartment-specific manner. Despite the importance of the endoplasmic reticulum (ER) as a platform for various biochemical reactions, such as protein synthesis, protein trafficking, and intracellular calcium control, the contribution of the ER to neuronal compartment-specific functions and plasticity remains elusive. Recent advances in the development of live imaging and serial scanning electron microscopy (sSEM) analysis have revealed that the neuronal ER is a highly dynamic organelle with compartment-specific structures. sSEM studies also revealed that the ER forms contacts with other membranes, such as the mitochondria and plasma membrane, although little is known about the functions of these ER-membrane contacts. In this review, we discuss the mechanisms and physiological roles of the ER structure and ER-mitochondria contacts in synaptic transmission and plasticity, thereby highlighting a potential link between organelle ultrastructure and neuronal functions.
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Affiliation(s)
- Masafumi TSUBOI
- Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
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31
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Borgese N, Navone F, Nukina N, Yamanaka T. Mutant VAPB: Culprit or Innocent Bystander of Amyotrophic Lateral Sclerosis? CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2021; 4:25152564211022515. [PMID: 37366377 PMCID: PMC10243577 DOI: 10.1177/25152564211022515] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 05/08/2021] [Accepted: 05/12/2021] [Indexed: 06/28/2023]
Abstract
Nearly twenty years ago a mutation in the VAPB gene, resulting in a proline to serine substitution (p.P56S), was identified as the cause of a rare, slowly progressing, familial form of the motor neuron degenerative disease Amyotrophic Lateral Sclerosis (ALS). Since then, progress in unravelling the mechanistic basis of this mutation has proceeded in parallel with research on the VAP proteins and on their role in establishing membrane contact sites between the ER and other organelles. Analysis of the literature on cellular and animal models reviewed here supports the conclusion that P56S-VAPB, which is aggregation-prone, non-functional and unstable, is expressed at levels that are insufficient to support toxic gain-of-function or dominant negative effects within motor neurons. Instead, insufficient levels of the product of the single wild-type allele appear to be required for pathological effects, and may be the main driver of the disease. In light of the multiple interactions of the VAP proteins, we address the consequences of specific VAPB depletion and highlight various affected processes that could contribute to motor neuron degeneration. In the future, distinction of specific roles of each of the two VAP paralogues should help to further elucidate the basis of p.P56S familial ALS, as well as of other more common forms of the disease.
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Affiliation(s)
- Nica Borgese
- CNR Institute of
Neuroscience, Vedano al Lambro (MB), Italy
| | | | - Nobuyuki Nukina
- Laboratory of Structural
Neuropathology, Doshisha University Graduate School of Brain Science,
Kyoto, Japan
| | - Tomoyuki Yamanaka
- Laboratory of Structural
Neuropathology, Doshisha University Graduate School of Brain Science,
Kyoto, Japan
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32
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Neuronal Autophagy Regulates Presynaptic Neurotransmission by Controlling the Axonal Endoplasmic Reticulum. Neuron 2020; 109:299-313.e9. [PMID: 33157003 PMCID: PMC7837115 DOI: 10.1016/j.neuron.2020.10.005] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 08/22/2020] [Accepted: 10/05/2020] [Indexed: 12/21/2022]
Abstract
Neurons are known to rely on autophagy for removal of defective proteins or organelles to maintain synaptic neurotransmission and counteract neurodegeneration. In spite of its importance for neuronal health, the physiological substrates of neuronal autophagy in the absence of proteotoxic challenge have remained largely elusive. We use knockout mice conditionally lacking the essential autophagy protein ATG5 and quantitative proteomics to demonstrate that loss of neuronal autophagy causes selective accumulation of tubular endoplasmic reticulum (ER) in axons, resulting in increased excitatory neurotransmission and compromised postnatal viability in vivo. The gain in excitatory neurotransmission is shown to be a consequence of elevated calcium release from ER stores via ryanodine receptors accumulated in axons and at presynaptic sites. We propose a model where neuronal autophagy controls axonal ER calcium stores to regulate neurotransmission in healthy neurons and in the brain. Neuronal autophagy controls the endoplasmic reticulum (ER) in axons Loss of neuronal autophagy leads to increased excitatory neurotransmission Increased neurotransmission is due to elevated calcium release from ER stores
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33
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Oliva MK, Pérez-Moreno JJ, O’Shaughnessy J, Wardill TJ, O’Kane CJ. Endoplasmic Reticulum Lumenal Indicators in Drosophila Reveal Effects of HSP-Related Mutations on Endoplasmic Reticulum Calcium Dynamics. Front Neurosci 2020; 14:816. [PMID: 32903680 PMCID: PMC7438849 DOI: 10.3389/fnins.2020.00816] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 07/10/2020] [Indexed: 12/02/2022] Open
Abstract
Genes for endoplasmic reticulum (ER)-shaping proteins are among the most commonly mutated in hereditary spastic paraplegia (HSP). Mutation of these genes in model organisms can lead to disruption of the ER network. To investigate how the physiological roles of the ER might be affected by such disruption, we developed tools to interrogate its Ca2+ signaling function. We generated GAL4-driven Ca2+ sensors targeted to the ER lumen, to record ER Ca2+ fluxes in identified Drosophila neurons. Using GAL4 lines specific for Type Ib or Type Is larval motor neurons, we compared the responses of different lumenal indicators to electrical stimulation, in axons and presynaptic terminals. The most effective sensor, ER-GCaMP6-210, had a Ca2+ affinity close to the expected ER lumenal concentration. Repetitive nerve stimulation generally showed a transient increase of lumenal Ca2+ in both the axon and presynaptic terminals. Mutants lacking neuronal reticulon and REEP proteins, homologs of human HSP proteins, showed a larger ER lumenal evoked response compared to wild type; we propose mechanisms by which this phenotype could lead to neuronal dysfunction or degeneration. Our lines are useful additions to a Drosophila Ca2+ imaging toolkit, to explore the physiological roles of ER, and its pathophysiological roles in HSP and in axon degeneration more broadly.
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Affiliation(s)
- Megan K. Oliva
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | | | | | - Trevor J. Wardill
- College of Biological Sciences, University of Minnesota, Minneapolis, MN, United States
| | - Cahir J. O’Kane
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
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34
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Zaman MF, Nenadic A, Radojičić A, Rosado A, Beh CT. Sticking With It: ER-PM Membrane Contact Sites as a Coordinating Nexus for Regulating Lipids and Proteins at the Cell Cortex. Front Cell Dev Biol 2020; 8:675. [PMID: 32793605 PMCID: PMC7387695 DOI: 10.3389/fcell.2020.00675] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 07/03/2020] [Indexed: 12/31/2022] Open
Abstract
Membrane contact sites between the cortical endoplasmic reticulum (ER) and the plasma membrane (PM) provide a direct conduit for small molecule transfer and signaling between the two largest membranes of the cell. Contact is established through ER integral membrane proteins that physically tether the two membranes together, though the general mechanism is remarkably non-specific given the diversity of different tethering proteins. Primary tethers including VAMP-associated proteins (VAPs), Anoctamin/TMEM16/Ist2p homologs, and extended synaptotagmins (E-Syts), are largely conserved in most eukaryotes and are both necessary and sufficient for establishing ER-PM association. In addition, other species-specific ER-PM tether proteins impart unique functional attributes to both membranes at the cell cortex. This review distils recent functional and structural findings about conserved and species-specific tethers that form ER-PM contact sites, with an emphasis on their roles in the coordinate regulation of lipid metabolism, cellular structure, and responses to membrane stress.
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Affiliation(s)
- Mohammad F Zaman
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada
| | - Aleksa Nenadic
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada
| | - Ana Radojičić
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada.,Department of Botany, University of British Columbia, Vancouver, BC, Canada
| | - Abel Rosado
- Department of Botany, University of British Columbia, Vancouver, BC, Canada
| | - Christopher T Beh
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada.,The Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, BC, Canada
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35
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Kumar R, Donakonda S, Müller SA, Lichtenthaler SF, Bötzel K, Höglinger GU, Koeglsperger T. Basic Fibroblast Growth Factor 2-Induced Proteome Changes Endorse Lewy Body Pathology in Hippocampal Neurons. iScience 2020; 23:101349. [PMID: 32707433 PMCID: PMC7381695 DOI: 10.1016/j.isci.2020.101349] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 06/11/2020] [Accepted: 07/03/2020] [Indexed: 12/15/2022] Open
Abstract
Hippocampal Lewy body pathology (LBP) is associated with changes in neurotrophic factor signaling and neuronal energy metabolism. LBP progression is attributed to the aggregation of α-synuclein (α-Syn) and its cell-to-cell transmission via extracellular vehicles (EVs). We recently discovered an enhanced EV release in basic fibroblast growth factor (bFGF)-treated hippocampal neurons. Here, we examined the EV and cell lysate proteome changes in bFGF-treated hippocampal neurons. We identified n = 2,310 differentially expressed proteins (DEPs) induced by bFGF. We applied weighted protein co-expression network analysis (WPCNA) to generate protein modules from DEPs and mapped them to published LBP datasets. This approach revealed n = 532 LBP-linked DEPs comprising key α-Syn-interacting proteins, LBP-associated RNA-binding proteins (RBPs), and neuronal ion channels and receptors that can impact LBP onset and progression. In summary, our deep proteomic analysis affirms the potential influence of bFGF signaling on LBP-related proteome changes and associated molecular interactions.
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Affiliation(s)
- Rohit Kumar
- German Center for Neurodegenerative Diseases (DZNE), 81337 Munich, Germany; Faculty of Medicine, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany; Department of Neurology, Ludwig Maximilian University, 81377 Munich, Germany.
| | - Sainitin Donakonda
- Institute of Immunology and Experimental Oncology, Technical University of Munich, 81675 Munich, Germany
| | - Stephan A Müller
- German Center for Neurodegenerative Diseases (DZNE), 81337 Munich, Germany
| | - Stefan F Lichtenthaler
- German Center for Neurodegenerative Diseases (DZNE), 81337 Munich, Germany; Neuroproteomics, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany; Munich Cluster for Systems Neurology (SyNergy), 81377 Munich, Germany
| | - Kai Bötzel
- Department of Neurology, Ludwig Maximilian University, 81377 Munich, Germany
| | - Günter U Höglinger
- German Center for Neurodegenerative Diseases (DZNE), 81337 Munich, Germany; Faculty of Medicine, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany; Department of Neurology, Hannover Medical School (MHH), 30625 Hannover, Germany
| | - Thomas Koeglsperger
- German Center for Neurodegenerative Diseases (DZNE), 81337 Munich, Germany; Department of Neurology, Ludwig Maximilian University, 81377 Munich, Germany.
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Willems J, de Jong APH, Scheefhals N, Mertens E, Catsburg LAE, Poorthuis RB, de Winter F, Verhaagen J, Meye FJ, MacGillavry HD. ORANGE: A CRISPR/Cas9-based genome editing toolbox for epitope tagging of endogenous proteins in neurons. PLoS Biol 2020; 18:e3000665. [PMID: 32275651 PMCID: PMC7176289 DOI: 10.1371/journal.pbio.3000665] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 04/22/2020] [Accepted: 03/27/2020] [Indexed: 12/15/2022] Open
Abstract
The correct subcellular distribution of proteins establishes the complex morphology and function of neurons. Fluorescence microscopy techniques are invaluable to investigate subcellular protein distribution, but they suffer from the limited ability to efficiently and reliably label endogenous proteins with fluorescent probes. We developed ORANGE: Open Resource for the Application of Neuronal Genome Editing, which mediates targeted genomic integration of epitope tags in rodent dissociated neuronal culture, in organotypic slices, and in vivo. ORANGE includes a knock-in library for in-depth investigation of endogenous protein distribution, viral vectors, and a detailed two-step cloning protocol to develop knock-ins for novel targets. Using ORANGE with (live-cell) superresolution microscopy, we revealed the dynamic nanoscale organization of endogenous neurotransmitter receptors and synaptic scaffolding proteins, as well as previously uncharacterized proteins. Finally, we developed a mechanism to create multiple knock-ins in neurons, mediating multiplex imaging of endogenous proteins. Thus, ORANGE enables quantification of expression, distribution, and dynamics for virtually any protein in neurons at nanoscale resolution. This study describes the development of a genome editing toolbox (ORANGE) for endogenous tagging of proteins in neurons. This open resource allows the investigation of protein localization and dynamics in neurons using live-cell and super-resolution imaging techniques.
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Affiliation(s)
- Jelmer Willems
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, the Netherlands
| | - Arthur P. H. de Jong
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, the Netherlands
| | - Nicky Scheefhals
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, the Netherlands
| | - Eline Mertens
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, the Netherlands
| | - Lisa A. E. Catsburg
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, the Netherlands
| | - Rogier B. Poorthuis
- Department of Translational Neuroscience, UMC Utrecht Brain Center, Utrecht University, Utrecht, the Netherlands
| | - Fred de Winter
- Laboratory for Neuroregeneration, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, the Netherlands
| | - Joost Verhaagen
- Laboratory for Neuroregeneration, Netherlands Institute for Neuroscience, Royal Netherlands Academy of Arts and Sciences, Amsterdam, the Netherlands
| | - Frank J. Meye
- Department of Translational Neuroscience, UMC Utrecht Brain Center, Utrecht University, Utrecht, the Netherlands
| | - Harold D. MacGillavry
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht, the Netherlands
- * E-mail:
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Öztürk Z, O’Kane CJ, Pérez-Moreno JJ. Axonal Endoplasmic Reticulum Dynamics and Its Roles in Neurodegeneration. Front Neurosci 2020; 14:48. [PMID: 32116502 PMCID: PMC7025499 DOI: 10.3389/fnins.2020.00048] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 01/13/2020] [Indexed: 12/13/2022] Open
Abstract
The physical continuity of axons over long cellular distances poses challenges for their maintenance. One organelle that faces this challenge is endoplasmic reticulum (ER); unlike other intracellular organelles, this forms a physically continuous network throughout the cell, with a single membrane and a single lumen. In axons, ER is mainly smooth, forming a tubular network with occasional sheets or cisternae and low amounts of rough ER. It has many potential roles: lipid biosynthesis, glucose homeostasis, a Ca2+ store, protein export, and contacting and regulating other organelles. This tubular network structure is determined by ER-shaping proteins, mutations in some of which are causative for neurodegenerative disorders such as hereditary spastic paraplegia (HSP). While axonal ER shares many features with the tubular ER network in other contexts, these features must be adapted to the long and narrow dimensions of axons. ER appears to be physically continuous throughout axons, over distances that are enormous on a subcellular scale. It is therefore a potential channel for long-distance or regional communication within neurons, independent of action potentials or physical transport of cargos, but involving its physiological roles such as Ca2+ or organelle homeostasis. Despite its apparent stability, axonal ER is highly dynamic, showing features like anterograde and retrograde transport, potentially reflecting continuous fusion and breakage of the network. Here we discuss the transport processes that must contribute to this dynamic behavior of ER. We also discuss the model that these processes underpin a homeostatic process that ensures both enough ER to maintain continuity of the network and repair breaks in it, but not too much ER that might disrupt local cellular physiology. Finally, we discuss how failure of ER organization in axons could lead to axon degenerative diseases, and how a requirement for ER continuity could make distal axons most susceptible to degeneration in conditions that disrupt ER continuity.
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Affiliation(s)
| | - Cahir J. O’Kane
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
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Pires G, McElligott S, Drusinsky S, Halliday G, Potier MC, Wisniewski T, Drummond E. Secernin-1 is a novel phosphorylated tau binding protein that accumulates in Alzheimer's disease and not in other tauopathies. Acta Neuropathol Commun 2019; 7:195. [PMID: 31796108 PMCID: PMC6892024 DOI: 10.1186/s40478-019-0848-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 11/14/2019] [Indexed: 12/13/2022] Open
Abstract
We recently identified Secernin-1 (SCRN1) as a novel amyloid plaque associated protein using localized proteomics. Immunohistochemistry studies confirmed that SCRN1 was present in plaque-associated dystrophic neurites and also revealed distinct and abundant co-localization with neurofibrillary tangles (NFTs). Little is known about the physiological function of SCRN1 and its role in Alzheimer's disease (AD) and other neurodegenerative diseases has not been studied. Therefore, we performed a comprehensive study of SCRN1 distribution in neurodegenerative diseases. Immunohistochemistry was used to map SCRN1 accumulation throughout the progression of AD in a cohort of 58 patients with a range of NFT pathology (Abundant NFT, n = 21; Moderate NFT, n = 22; Low/No NFT, n = 15), who were clinically diagnosed as having AD, mild cognitive impairment or normal cognition. SCRN1 accumulation was also examined in two cases with both Frontotemporal Lobar Degeneration (FTLD)-Tau and AD-related neuropathology, cases of Down Syndrome (DS) with AD (n = 5), one case of hereditary cerebral hemorrhage with amyloidosis - Dutch type (HCHWA-D) and other non-AD tauopathies including: primary age-related tauopathy (PART, [n = 5]), Corticobasal Degeneration (CBD, [n = 5]), Progressive Supranuclear Palsy (PSP, [n = 5]) and Pick's disease (PiD, [n = 4]). Immunohistochemistry showed that SCRN1 was a neuronal protein that abundantly accumulated in NFTs and plaque-associated dystrophic neurites throughout the progression of AD. Quantification of SCRN1 immunohistochemistry confirmed that SCRN1 preferentially accumulated in NFTs in comparison to surrounding non-tangle containing neurons at both early and late stages of AD. Similar results were observed in DS with AD and PART. However, SCRN1 did not co-localize with phosphorylated tau inclusions in CBD, PSP or PiD. Co-immunoprecipitation revealed that SCRN1 interacted with phosphorylated tau in human AD brain tissue. Together, these results suggest that SCRN1 is uniquely associated with tau pathology in AD, DS and PART. As such, SCRN1 has potential as a novel therapeutic target and could serve as a useful biomarker to distinguish AD from other tauopathies.
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Affiliation(s)
- Geoffrey Pires
- Center for Cognitive Neurology and Department of Neurology, New York University School of Medicine, 435 East 30th Street, Rm 1017, New York, NY, 10016, USA
| | - Sacha McElligott
- Center for Cognitive Neurology and Department of Neurology, New York University School of Medicine, 435 East 30th Street, Rm 1017, New York, NY, 10016, USA
| | - Shiron Drusinsky
- Center for Cognitive Neurology and Department of Neurology, New York University School of Medicine, 435 East 30th Street, Rm 1017, New York, NY, 10016, USA
| | - Glenda Halliday
- Brain & Mind Centre and Central Clinical School, Faculty of Medicine and Health, University of Sydney, 94 Mallett Street, Camperdown, NSW, 2050, Australia
| | - Marie-Claude Potier
- Institut du Cerveau et de la Moelle épinière, CNRS UMR7225, INSERM U1127, UPMC, Hôpital de la Pitié-Salpêtrière, 47 Bd de l'Hôpital, Paris, France
| | - Thomas Wisniewski
- Center for Cognitive Neurology and Department of Neurology, New York University School of Medicine, 435 East 30th Street, Rm 1017, New York, NY, 10016, USA.
- Departments of Pathology and Psychiatry, New York University School of Medicine, 435 East 30th Street, Rm 1017, New York, NY, 10016, USA.
| | - Eleanor Drummond
- Center for Cognitive Neurology and Department of Neurology, New York University School of Medicine, 435 East 30th Street, Rm 1017, New York, NY, 10016, USA.
- Brain & Mind Centre and Central Clinical School, Faculty of Medicine and Health, University of Sydney, 94 Mallett Street, Camperdown, NSW, 2050, Australia.
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Bezprozvanny I, Kavalali ET. Presynaptic endoplasmic reticulum and neurotransmission. Cell Calcium 2019; 85:102133. [PMID: 31812114 DOI: 10.1016/j.ceca.2019.102133] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 11/25/2019] [Accepted: 11/25/2019] [Indexed: 11/19/2022]
Abstract
Synaptic transmission relies on rapid calcium (Ca2+) influx into presynaptic terminal via voltage-gated Ca2+ channels. However, smooth ER is present in presynaptic terminals and accumulating evidence indicate that ER Ca2+ signaling may play a modulatory role in synaptic transmission. Most recent publication by Lindhout and colleagues (EMBO J, 38 (2019) e101345) suggested that the fragmentation state of the ER affects synaptic vesicle release. Here we discuss these results as well as several key publications that addressed a connection between ER Ca2+ signaling and synaptic transmission.
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Affiliation(s)
- Ilya Bezprozvanny
- Department of Physiology, The University of Texas Southwestern Medical Center, Dallas, TX 75390-9040, USA.
| | - Ege T Kavalali
- Department of Pharmacology and Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, 37240-7933, USA.
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Peng Y, Zhao W, Qu F, Jing J, Hu Y, Liu Y, Ding Z. Proteomic alterations underlie an association with teratozoospermia in obese mice sperm. Reprod Biol Endocrinol 2019; 17:82. [PMID: 31651332 PMCID: PMC6813985 DOI: 10.1186/s12958-019-0530-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 10/02/2019] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Obesity is a worldwide crisis impairing human health. In this condition, declines in sperm quality stem from reductions in sperm concentration, motility and increase in sperm deformity. The mechanism underlying these alterations remains largely unknown. This study, determined if obesity-associated proteomic expression patterns in mice sperm parallel those in spermatozoa obtained from obese humans. METHODS An obese mouse model was established via feeding a high-fat diet (HFD). Histological analysis identified testicular morphology and a computer assisted semen analyzer (CASA) evaluated sperm parameters. Proteome analysis was performed using a label-free quantitative LC-MS/MS system. Western blot, immunohistochemical and immunofluorescent analyses characterized protein expression levels and localization in testis, sperm and clinical samples. RESULTS Bodyweight gains on the HFD induced hepatic steatosis. Declines in sperm motility accompanied sperm deformity development. Differential proteomic analysis identified reduced cytoskeletal proteins, centrosome and spindle pole associated protein 1 (CSPP1) and Centrin 1 (CETN1), in sperm from obese mice. In normal weight mice, both CSPP1 and CETN1 were localized in the spermatocytes and spermatids. Their expression was appreciable in the post-acrosomal region parallel to the microtubule tracks of the manchette structure in spermatids, which affects spermatid head shaping and morphological maintenance. Moreover, CSPP1 was localized in the head-tail coupling apparatus of the mature sperm, while CETN1 expression was delimited to the post-acrosomal region within the sperm head. Importantly, sperm CSPP1 and CETN1 abundance in both the overweight and obese males decreased in comparison with that in normal weight men. CONCLUSION These findings show that regionally distinct expression and localization of CETN1 and CSPP1 is strongly related to spermiogenesis and sperm morphology maintaining. Obesity is associated with declines in the CETN1 and CSPP1 abundance and compromise of both sperm morphology in mice and relevant clinical samples. This parallelism between altered protein expression in mice and humans suggests that these effects may contribute to poor sperm quality including increased deformity.
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Affiliation(s)
- Yuanhong Peng
- Department of Histology, Embryology, Genetics and Developmental Biology, Shanghai Key Laboratory for Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Wenzhen Zhao
- Department of Histology and Embryology, School of Basic Medical Science, Dali University, Dali, 671000, Yunnan, China
- Institute of Reproductive Medicine, Dali University, Dali, 671000, Yunnan, China
| | - Fei Qu
- Department of Histology, Embryology, Genetics and Developmental Biology, Shanghai Key Laboratory for Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Jia Jing
- Department of Histology, Embryology, Genetics and Developmental Biology, Shanghai Key Laboratory for Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Yanqin Hu
- Department of Histology, Embryology, Genetics and Developmental Biology, Shanghai Key Laboratory for Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Yue Liu
- Department of Histology, Embryology, Genetics and Developmental Biology, Shanghai Key Laboratory for Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
| | - Zhide Ding
- Department of Histology, Embryology, Genetics and Developmental Biology, Shanghai Key Laboratory for Reproductive Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
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