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Hjartarson HT, Skott H, Granberg T, Paucar M. Phenotypic variability in a large kindred with spastic paraplegia associated with a novel REEP1 variant. eNeurologicalSci 2024; 35:100497. [PMID: 38525447 PMCID: PMC10957410 DOI: 10.1016/j.ensci.2024.100497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 02/14/2024] [Accepted: 02/22/2024] [Indexed: 03/26/2024] Open
Abstract
Background and objectives The aim of this study is to provide a comprehensive characterization of a large Estonian family spanning five generations with seventeen individuals affected by spastic paraplegia associated with a novel variant in the receptor expression-enhancing protein-1 (REEP1) gene. Methods Comprehensive clinical evaluation, neuroimaging, and neurophysiological studies were performed on six patients who provided oral and written consent. Whole-exome sequencing was performed on the index case. Targeted carrier testing was done in all other available affected and at-risk relatives. Results Four individuals presented with pure spastic paraplegia, with onset from early childhood to adult age. None had bladder or bowel dysfunction. Two subjectively asymptomatic mutation carriers displayed pyramidal signs on examination. Imaging of the neuroaxis was normal in three patients, three had MRI findings interpreted as unrelated. Motor evoked potential (MEP) was abnormal in five; the patient with the longest disease duration had additional somatosensory evoked potential (SSEP) abnormalities. The novel splice-site variant, c.32 + 1G > C in the REEP1 gene, found in the index case, co-segregates with disease in the family. Expressivity in this family is variable. Conclusion Our findings are in keeping with previous descriptions of the SPG31 spectrum. The phenotype associated with splice variants is not necessarily more severe than other conventional REEP1 variants. As for other forms of familial spastic paraplegias, the factors modulating variable expressivity in SPG31 are still unknown.
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Affiliation(s)
- Helgi Thor Hjartarson
- Department of Pediatric Neurology, Karolinska University Hospital, Stockholm, Sweden
| | - Humberto Skott
- Department of Neurophysiology, Karolinska University Hospital, Stockholm, Sweden
| | - Tobias Granberg
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
- Department of Neuroradiology, Karolinska University Hospital, Stockholm, Sweden
| | - Martin Paucar
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
- Department of Neurology, Karolinska University Hospital, Stockholm, Sweden
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Englisch AS, Hofbrucker-MacKenzie SA, Izadi-Seitz M, Kessels MM, Qualmann B. Ankrd26 is a retinoic acid-responsive plasma membrane-binding and -shaping protein critical for proper cell differentiation. Cell Rep 2024; 43:113939. [PMID: 38493476 DOI: 10.1016/j.celrep.2024.113939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 01/17/2024] [Accepted: 02/23/2024] [Indexed: 03/19/2024] Open
Abstract
Morphogens are important triggers for differentiation processes. Yet, downstream effectors that organize cell shape changes in response to morphogenic cues, such as retinoic acid, largely remain elusive. Additionally, derailed plasma membrane-derived signaling often is associated with cancer. We identify Ankrd26 as a critical player in cellular differentiation and as plasma membrane-localized protein able to self-associate and form clusters at the plasma membrane in response to retinoic acid. We show that Ankrd26 uses an N-terminal amphipathic structure for membrane binding and bending. Importantly, in an acute myeloid leukemia-associated Ankrd26 mutant, this critical structure was absent, and Ankrd26's membrane association and shaping abilities were impaired. In line with this, the mutation rendered Ankrd26 inactive in both gain-of-function and loss-of-function/rescue studies addressing retinoic acid/brain-derived neurotrophic factor (BDNF)-induced neuroblastoma differentiation. Our results highlight the importance and molecular details of Ankrd26-mediated organizational platforms for cellular differentiation at the plasma membrane and how impairment of these platforms leads to cancer-associated pathomechanisms involving these Ankrd26 properties.
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Affiliation(s)
- Anna Sofie Englisch
- Institute of Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Nonnenplan 2-4, 07743 Jena, Germany
| | - Sarah Ann Hofbrucker-MacKenzie
- Institute of Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Nonnenplan 2-4, 07743 Jena, Germany
| | - Maryam Izadi-Seitz
- Institute of Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Nonnenplan 2-4, 07743 Jena, Germany
| | - Michael Manfred Kessels
- Institute of Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Nonnenplan 2-4, 07743 Jena, Germany.
| | - Britta Qualmann
- Institute of Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Nonnenplan 2-4, 07743 Jena, Germany.
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3
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Lim JH, Kang HM, Kim DH, Jeong B, Lee DY, Lee JR, Baek JY, Cho HS, Son MY, Kim DS, Kim NS, Jung CR. ARL6IP1 gene delivery reduces neuroinflammation and neurodegenerative pathology in hereditary spastic paraplegia model. J Exp Med 2024; 221:e20230367. [PMID: 37934410 PMCID: PMC10630151 DOI: 10.1084/jem.20230367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 07/24/2023] [Accepted: 09/25/2023] [Indexed: 11/08/2023] Open
Abstract
ARL6IP1 is implicated in hereditary spastic paraplegia (HSP), but the specific pathogenic mechanism leading to neurodegeneration has not been elucidated. Here, we clarified the molecular mechanism of ARL6IP1 in HSP using in vitro and in vivo models. The Arl6ip1 knockout (KO) mouse model was generated to represent the clinically involved frameshift mutations and mimicked the HSP phenotypes. Notably, in vivo brain histopathological analysis revealed demyelination of the axon and neuroinflammation in the white matter, including the corticospinal tract. In in vitro experiments, ARL6IP1 silencing caused cell death during neuronal differentiation and mitochondrial dysfunction by dysregulated autophagy. ARL6IP1 localized on mitochondria-associated membranes (MAMs) to maintain endoplasmic reticulum and mitochondrial homeostasis via direct interaction with LC3B and BCl2L13. ARL6IP1 played a crucial role in connecting the endoplasmic reticulum and mitochondria as a member of MAMs. ARL6IP1 gene therapy reduced HSP phenotypes and restored pathophysiological changes in the Arl6ip1 KO model. Our results established that ARL6IP1 could be a potential target for HSP gene therapy.
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Affiliation(s)
- Jung Hwa Lim
- Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
- Department of Functional Genomics, Korea University of Science and Technology, Daejeon, Republic of Korea
| | - Hyun Mi Kang
- Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
- Department of Functional Genomics, Korea University of Science and Technology, Daejeon, Republic of Korea
| | - Dae Hun Kim
- Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
- Department of Functional Genomics, Korea University of Science and Technology, Daejeon, Republic of Korea
| | - Bohyeon Jeong
- Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
| | - Da Yong Lee
- Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
- Department of Functional Genomics, Korea University of Science and Technology, Daejeon, Republic of Korea
| | - Jae-Ran Lee
- Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
- Department of Functional Genomics, Korea University of Science and Technology, Daejeon, Republic of Korea
| | - Jeong Yeob Baek
- Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
| | - Hyun-Soo Cho
- Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
- Department of Functional Genomics, Korea University of Science and Technology, Daejeon, Republic of Korea
| | - Mi-Young Son
- Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
- Department of Functional Genomics, Korea University of Science and Technology, Daejeon, Republic of Korea
| | - Dae Soo Kim
- Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
- Department of Functional Genomics, Korea University of Science and Technology, Daejeon, Republic of Korea
| | - Nam-Soon Kim
- Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
- Department of Functional Genomics, Korea University of Science and Technology, Daejeon, Republic of Korea
| | - Cho-Rok Jung
- Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
- Department of Functional Genomics, Korea University of Science and Technology, Daejeon, Republic of Korea
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4
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Izadi M, Wolf D, Seemann E, Ori A, Schwintzer L, Steiniger F, Kessels MM, Qualmann B. Membrane shapers from two distinct superfamilies cooperate in the development of neuronal morphology. J Cell Biol 2023; 222:e202211032. [PMID: 37318382 PMCID: PMC10274853 DOI: 10.1083/jcb.202211032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 03/27/2023] [Accepted: 05/15/2023] [Indexed: 06/16/2023] Open
Abstract
Membrane-shaping proteins are driving forces behind establishment of proper cell morphology and function. Yet, their reported structural and in vitro properties are noticeably inconsistent with many physiological membrane topology requirements. We demonstrate that dendritic arborization of neurons is powered by physically coordinated shaping mechanisms elicited by members of two distinct classes of membrane shapers: the F-BAR protein syndapin I and the N-Ank superfamily protein ankycorbin. Strikingly, membrane-tubulating activities by syndapin I, which would be detrimental during dendritic branching, were suppressed by ankycorbin. Ankycorbin's integration into syndapin I-decorated membrane surfaces instead promoted curvatures and topologies reflecting those observed physiologically. In line with the functional importance of this mechanism, ankycorbin- and syndapin I-mediated functions in dendritic arborization mutually depend on each other and on a surprisingly specific interface mediating complex formation of the two membrane shapers. These striking results uncovered cooperative and interdependent functions of members of two fundamentally different membrane shaper superfamilies as a previously unknown, pivotal principle in neuronal shape development.
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Affiliation(s)
- Maryam Izadi
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, Jena, Germany
| | - David Wolf
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, Jena, Germany
| | - Eric Seemann
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, Jena, Germany
| | - Alessandro Ori
- Leibniz Institute on Aging—Fritz Lipmann Institute, Jena, Germany
| | - Lukas Schwintzer
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, Jena, Germany
| | - Frank Steiniger
- Electron Microscopy Center, Jena University Hospital—Friedrich Schiller University Jena, Jena, Germany
| | - Michael Manfred Kessels
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, Jena, Germany
| | - Britta Qualmann
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, Jena, Germany
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5
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Foronda H, Fu Y, Covarrubias-Pinto A, Bocker HT, González A, Seemann E, Franzka P, Bock A, Bhaskara RM, Liebmann L, Hoffmann ME, Katona I, Koch N, Weis J, Kurth I, Gleeson JG, Reggiori F, Hummer G, Kessels MM, Qualmann B, Mari M, Dikić I, Hübner CA. Heteromeric clusters of ubiquitinated ER-shaping proteins drive ER-phagy. Nature 2023:10.1038/s41586-023-06090-9. [PMID: 37225994 DOI: 10.1038/s41586-023-06090-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 04/17/2023] [Indexed: 05/26/2023]
Abstract
Membrane-shaping proteins characterized by reticulon homology domains play an important part in the dynamic remodelling of the endoplasmic reticulum (ER). An example of such a protein is FAM134B, which can bind LC3 proteins and mediate the degradation of ER sheets through selective autophagy (ER-phagy)1. Mutations in FAM134B result in a neurodegenerative disorder in humans that mainly affects sensory and autonomic neurons2. Here we report that ARL6IP1, another ER-shaping protein that contains a reticulon homology domain and is associated with sensory loss3, interacts with FAM134B and participates in the formation of heteromeric multi-protein clusters required for ER-phagy. Moreover, ubiquitination of ARL6IP1 promotes this process. Accordingly, disruption of Arl6ip1 in mice causes an expansion of ER sheets in sensory neurons that degenerate over time. Primary cells obtained from Arl6ip1-deficient mice or from patients display incomplete budding of ER membranes and severe impairment of ER-phagy flux. Therefore, we propose that the clustering of ubiquitinated ER-shaping proteins facilitates the dynamic remodelling of the ER during ER-phagy and is important for neuronal maintenance.
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Affiliation(s)
- Hector Foronda
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Yangxue Fu
- Institute of Biochemistry II, Goethe University School of Medicine, Frankfurt am Main, Germany
| | | | - Hartmut T Bocker
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Jena, Germany
- Blink AG, Jena, Germany
| | - Alexis González
- Institute of Biochemistry II, Goethe University School of Medicine, Frankfurt am Main, Germany
| | - Eric Seemann
- Institute for Biochemistry I, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Patricia Franzka
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Andrea Bock
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Ramachandra M Bhaskara
- Institute of Biochemistry II, Goethe University School of Medicine, Frankfurt am Main, Germany
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt am Main, Germany
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | - Lutz Liebmann
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Marina E Hoffmann
- Institute of Biochemistry II, Goethe University School of Medicine, Frankfurt am Main, Germany
| | - Istvan Katona
- Institute of Neuropathology, RWTH Aachen University Hospital, Aachen, Germany
| | - Nicole Koch
- Institute for Biochemistry I, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Joachim Weis
- Institute of Neuropathology, RWTH Aachen University Hospital, Aachen, Germany
| | - Ingo Kurth
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Jena, Germany
- Institute for Human Genetics and Genomic Medicine, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Joseph G Gleeson
- Department of Neurosciences, Rady Children's Institute for Genomic Medicine Howard Hughes Medical Institute, University of California, San Diego, La Jolla, CA, USA
| | - Fulvio Reggiori
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- Department of Biomedicine, Aarhus University, Aarhus C, Denmark
- Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Aarhus C, Denmark
| | - Gerhard Hummer
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Frankfurt am Main, Germany
- Institute of Biophysics, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Michael M Kessels
- Institute for Biochemistry I, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Britta Qualmann
- Institute for Biochemistry I, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Muriel Mari
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
- Department of Biomedicine, Aarhus University, Aarhus C, Denmark
| | - Ivan Dikić
- Institute of Biochemistry II, Goethe University School of Medicine, Frankfurt am Main, Germany.
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, Frankfurt am Main, Germany.
| | - Christian A Hübner
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Jena, Germany.
- Center for Rare Diseases, Jena University Hospital, Friedrich Schiller University, Jena, Germany.
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Le W, Wang P, Al-Nusaif M, Zhang J, Yang H, Yang Y, Kim K, Li S, Liu C, Cai H. Pathological characteristics of axons and proteome patterns in midbrain dopaminergic neurodegeneration induced by WDR45-deficiency. Res Sq 2023:rs.3.rs-2901370. [PMID: 37292937 PMCID: PMC10246098 DOI: 10.21203/rs.3.rs-2901370/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Background Although WD repeats domain 45 (WDR45) mutations have been linked to β-propeller protein-associated neurodegeneration (BPAN), the precise molecular and cellular mechanisms behind this disease remain elusive. This study aims to shed light on the effects of WDR45-deficiency on neurodegeneration, specifically axonal degeneration, within the midbrain dopaminergic (DAergic) system. By examining pathological and molecular alterations, we hope to better understand the disease process. Methods To investigate the effects of WDR45 dysfunction on mouse behaviors and DAergic neurons, we developed a mouse model in which WDR45 was conditionally knocked out in midbrain DAergic neurons (WDR45cKO). Through a longitudinal study, we assessed alterations in mouse behavior using open field, rotarod, Y-maze, and 3-chamber social approach tests. To examine the pathological changes in DAergic neuron soma and axons, we utilized a combination of immunofluorescence staining and transmission electron microscopy. Additionally, we performed proteomic analyses of the striatum to identify the molecules and processes involved in striatal pathology. Results Our study of WDR45cKO mice revealed a range of deficits, including impaired motor function, emotional instability, and memory loss, coinciding with the profound loss of midbrain DAergic neurons. Prior to neuronal loss, we observed massive axonal enlargements in both the dorsal and ventral striatum. These enlargements were characterized by the accumulation of extensively fragmented tubular endoplasmic reticulum (ER), a hallmark of axonal degeneration. Additionally, we found that WDR45cKO mice exhibited disrupted autophagic flux. Proteomic analysis of the striatum in these mice showed that many differentially expressed proteins (DEPs) were enriched in amino acid, lipid, and tricarboxylic acid metabolisms. Of note, we observed significant alterations in the expression of genes encoding DEPs that regulate phospholipids catabolic and biosynthetic processes, such as lysophosphatidylcholine acyltransferase 1, ethanolamine-phosphate phospho-lyase, and abhydrolase domain containing 4, N-acyl phospholipase B. These findings suggest a possible link between phospholipid metabolism and striatal axon degeneration. Conclusions In this study, we have uncovered the molecular mechanisms underlying the contribution of WDR45-deficiency to axonal degeneration, revealing intricate relationships between tubular ER dysfunction, phospholipid metabolism, BPAN and other neurodegenerative diseases. These findings significantly advance our understanding of the fundamental molecular mechanisms driving neurodegeneration and may provide a foundation for developing novel, mechanistically-based therapeutic interventions.
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Affiliation(s)
- Weidong Le
- The First Affiliated Hospital Of Dalian Medical University
| | - Panpan Wang
- First Affiliated Hospital of Dalian Medical University
| | | | - Jun Zhang
- First Affiliated Hospital of Dalian Medical University
| | - Huijia Yang
- First Affiliated Hospital of Dalian Medical University
| | - Yuting Yang
- First Affiliated Hospital of Dalian Medical University
| | - Kunhyok Kim
- First Affiliated Hospital of Dalian Medical University
| | - Song Li
- First Affiliated Hospital of Dalian Medical University
| | - Cong Liu
- Shanghai Institute of Organic Chemistry
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Ho NJ, Chen X, Lei Y, Gu S. Decoding hereditary spastic paraplegia pathogenicity through transcriptomic profiling. Zool Res 2023; 44:650-662. [PMID: 37161652 PMCID: PMC10236304 DOI: 10.24272/j.issn.2095-8137.2022.281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 05/10/2023] [Indexed: 05/11/2023] Open
Abstract
Hereditary spastic paraplegia (HSP) is a group of genetic motor neuron diseases resulting from length-dependent axonal degeneration of the corticospinal upper motor neurons. Due to the advancement of next-generation sequencing, more than 70 novel HSP disease-causing genes have been identified in the past decade. Despite this, our understanding of HSP physiopathology and the development of efficient management and treatment strategies remain poor. One major challenge in studying HSP pathogenicity is selective neuronal vulnerability, characterized by the manifestation of clinical symptoms that are restricted to specific neuronal populations, despite the presence of germline disease-causing variants in every cell of the patient. Furthermore, disease genes may exhibit ubiquitous expression patterns and involve a myriad of different pathways to cause motor neuron degeneration. In the current review, we explore the correlation between transcriptomic data and clinical manifestations, as well as the importance of interspecies models by comparing tissue-specific transcriptomic profiles of humans and mice, expression patterns of different genes in the brain during development, and single-cell transcriptomic data from related tissues. Furthermore, we discuss the potential of emerging single-cell RNA sequencing technologies to resolve unanswered questions related to HSP pathogenicity.
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Affiliation(s)
- Nicolas James Ho
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Xiao Chen
- Dr. Li Dak Sum-Yip Yio Chin Center for Stem Cells and Regenerative Medicine and Department of Orthopedic Surgery of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
- Key Laboratory of Tissue Engineering and Regenerative Medicine of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
- Zhejiang University-University of Edinburgh Institute & School of Basic Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
- Department of Sports Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
- China Orthopedic Regenerative Medicine Group (CORMed), Hangzhou, Zhejiang, 310058 China
| | - Yong Lei
- School of Medicine, The Chinese University of Hong Kong (Shenzhen), Shenzhen, Guangdong 518172, China
- The Chinese University of Hong Kong (Shenzhen), Shenzhen Futian Biomedical Innovation R&D Center, Shenzhen, Guangdong 518172, China. E-mail:
| | - Shen Gu
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
- Key Laboratory for Regenerative Medicine, Ministry of Education, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
- Kunming Institute of Zoology Chinese Academy of Sciences, The Chinese University of Hong Kong Joint Laboratory of Bioresources and Molecular Research of Common Diseases, Hong Kong SAR, China
- Hong Kong Branch of CAS Center for Excellence in Animal Evolution and Genetics, The Chinese University of Hong Kong, Hong Kong SAR, China. E-mail:
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Naef V, Meschini MC, Tessa A, Morani F, Corsinovi D, Ogi A, Marchese M, Ori M, Santorelli FM, Doccini S. Converging Role for REEP1/SPG31 in Oxidative Stress. Int J Mol Sci 2023; 24:ijms24043527. [PMID: 36834939 PMCID: PMC9959426 DOI: 10.3390/ijms24043527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 02/02/2023] [Accepted: 02/07/2023] [Indexed: 02/12/2023] Open
Abstract
Mutations in the receptor expression-enhancing protein 1 gene (REEP1) are associated with hereditary spastic paraplegia type 31 (SPG31), a neurological disorder characterized by length-dependent degeneration of upper motor neuron axons. Mitochondrial dysfunctions have been observed in patients harboring pathogenic variants in REEP1, suggesting a key role of bioenergetics in disease-related manifestations. Nevertheless, the regulation of mitochondrial function in SPG31 remains unclear. To elucidate the pathophysiology underlying REEP1 deficiency, we analyzed in vitro the impact of two different mutations on mitochondrial metabolism. Together with mitochondrial morphology abnormalities, loss-of-REEP1 expression highlighted a reduced ATP production with increased susceptibility to oxidative stress. Furthermore, to translate these findings from in vitro to preclinical models, we knocked down REEP1 in zebrafish. Zebrafish larvae showed a significant defect in motor axon outgrowth leading to motor impairment, mitochondrial dysfunction, and reactive oxygen species accumulation. Protective antioxidant agents such as resveratrol rescued free radical overproduction and ameliorated the SPG31 phenotype both in vitro and in vivo. Together, our findings offer new opportunities to counteract neurodegeneration in SPG31.
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Affiliation(s)
- Valentina Naef
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Stella Maris Foundation, 56128 Pisa, Italy
| | - Maria C. Meschini
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Stella Maris Foundation, 56128 Pisa, Italy
| | - Alessandra Tessa
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Stella Maris Foundation, 56128 Pisa, Italy
| | - Federica Morani
- Department of Biology, University of Pisa, 56126 Pisa, Italy
| | - Debora Corsinovi
- Department of Biology, University of Pisa, 56126 Pisa, Italy
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, 56126 Pisa, Italy
| | - Asahi Ogi
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Stella Maris Foundation, 56128 Pisa, Italy
| | - Maria Marchese
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Stella Maris Foundation, 56128 Pisa, Italy
| | - Michela Ori
- Department of Biology, University of Pisa, 56126 Pisa, Italy
| | - Filippo M. Santorelli
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Stella Maris Foundation, 56128 Pisa, Italy
| | - Stefano Doccini
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, IRCCS Stella Maris Foundation, 56128 Pisa, Italy
- Correspondence: ; Tel.: +39-050-886-311
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9
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Qin S, You P, Yu H, Su B. REEP1 Preserves Motor Function in SOD1G93A Mice by Improving Mitochondrial Function via Interaction with NDUFA4. Neurosci Bull 2022:10.1007/s12264-022-00995-7. [DOI: 10.1007/s12264-022-00995-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 09/25/2022] [Indexed: 12/23/2022] Open
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10
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Peotter JL, Pustova I, Lettman MM, Shatadal S, Bradberry MM, Winter-Reed AD, Charan M, Sharkey EE, Alvin JR, Bren AM, Oie AK, Chapman ER, Salamat MS, Audhya A. TFG regulates secretory and endosomal sorting pathways in neurons to promote their activity and maintenance. Proc Natl Acad Sci U S A 2022; 119:e2210649119. [PMID: 36161950 PMCID: PMC9546632 DOI: 10.1073/pnas.2210649119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 08/18/2022] [Indexed: 02/01/2023] Open
Abstract
Molecular pathways that intrinsically regulate neuronal maintenance are poorly understood, but rare pathogenic mutations that underlie neurodegenerative disease can offer important insights into the mechanisms that facilitate lifelong neuronal function. Here, we leverage a rat model to demonstrate directly that the TFG p.R106C variant implicated previously in complicated forms of hereditary spastic paraplegia (HSP) underlies progressive spastic paraparesis with accompanying ventriculomegaly and thinning of the corpus callosum, consistent with disease phenotypes identified in adolescent patients. Analyses of primary cortical neurons obtained from CRISPR-Cas9-edited animals reveal a kinetic delay in biosynthetic secretory protein transport from the endoplasmic reticulum (ER), in agreement with prior induced pluripotent stem cell-based studies. Moreover, we identify an unexpected role for TFG in the trafficking of Rab4A-positive recycling endosomes specifically within axons and dendrites. Impaired TFG function compromises the transport of at least a subset of endosomal cargoes, which we show results in down-regulated inhibitory receptor signaling that may contribute to excitation-inhibition imbalances. In contrast, the morphology and trafficking of other organelles, including mitochondria and lysosomes, are unaffected by the TFG p.R106C mutation. Our findings demonstrate a multifaceted role for TFG in secretory and endosomal protein sorting that is unique to cells of the central nervous system and highlight the importance of these pathways to maintenance of corticospinal tract motor neurons.
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Affiliation(s)
- Jennifer L. Peotter
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Iryna Pustova
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Molly M. Lettman
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Shalini Shatadal
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Mazdak M. Bradberry
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Allison D. Winter-Reed
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Maya Charan
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Erin E. Sharkey
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - James R. Alvin
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Alyssa M. Bren
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Annika K. Oie
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Edwin R. Chapman
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
- HHMI, University of Wisconsin-Madison, Madison, WI 53705
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53705
| | - M. Shahriar Salamat
- Department of Pathology and Laboratory Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
- Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Anjon Audhya
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
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11
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Abstract
Receptor expression-enhancing proteins (REEPs) are an evolutionarily conserved protein family that is pivotal to the structure and function of the endoplasmic reticulum (ER). The REEP family can be classified into two major subfamilies in higher species, the REEP1-4 and REEP5-6 subfamilies. Within the REEP1-4 subfamily, REEP1 and REEP2 are closely related, and REEP3 and REEP4 are similarly related. The REEP family is widely distributed in various tissues. Recent studies indicate that the REEP family is involved in many pathological and physiological processes, such as ER morphogenesis and remodeling, microtubule cytoskeleton regulation, and the trafficking and expression of G protein-coupled receptors (GPCRs). Moreover, the REEP family plays crucial roles in the occurrence and development of many diseases, including neurological diseases, diabetes, retinal diseases, cardiac diseases, infertility, obesity, oligoarticular juvenile idiopathic arthritis (OJIA), COVID-19, and cancer. In the present review, we describe the distribution and structure of the REEP family. Furthermore, we summarize the functions and the associated diseases of this family. Based on the pleiotropic actions of the REEP family, the study of its family members is crucial to understanding the relevant pathophysiological processes and developing strategies to modulate and control these related diseases. AVAILABILITY OF DATA AND MATERIAL: The datasets used or analyzed during the current study are available from the corresponding author on reasonable request.
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Affiliation(s)
- Sisi Fan
- Institute of Pharmacy and Pharmacology, Hunan Provincial Key Laboratory of tumor microenvironment responsive drug research, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical School, University of South China, Hengyang 421001, Hunan, China
| | - Huimei Liu
- Institute of Pharmacy and Pharmacology, Hunan Provincial Key Laboratory of tumor microenvironment responsive drug research, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical School, University of South China, Hengyang 421001, Hunan, China
| | - Lanfang Li
- Institute of Pharmacy and Pharmacology, Hunan Provincial Key Laboratory of tumor microenvironment responsive drug research, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, Hengyang Medical School, University of South China, Hengyang 421001, Hunan, China.
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12
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Zhu PP, Hung HF, Batchenkova N, Nixon-Abell J, Henderson J, Zheng P, Renvoisé B, Pang S, Xu CS, Saalfeld S, Funke J, Xie Y, Svara F, Hess HF, Blackstone C. Transverse endoplasmic reticulum expansion in hereditary spastic paraplegia corticospinal axons. Hum Mol Genet 2022; 31:2779-2795. [PMID: 35348668 PMCID: PMC9402237 DOI: 10.1093/hmg/ddac072] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 03/15/2022] [Accepted: 03/20/2022] [Indexed: 08/12/2023] Open
Abstract
Hereditary spastic paraplegias (HSPs) comprise a large group of inherited neurologic disorders affecting the longest corticospinal axons (SPG1-86 plus others), with shared manifestations of lower extremity spasticity and gait impairment. Common autosomal dominant HSPs are caused by mutations in genes encoding the microtubule-severing ATPase spastin (SPAST; SPG4), the membrane-bound GTPase atlastin-1 (ATL1; SPG3A) and the reticulon-like, microtubule-binding protein REEP1 (REEP1; SPG31). These proteins bind one another and function in shaping the tubular endoplasmic reticulum (ER) network. Typically, mouse models of HSPs have mild, later onset phenotypes, possibly reflecting far shorter lengths of their corticospinal axons relative to humans. Here, we have generated a robust, double mutant mouse model of HSP in which atlastin-1 is genetically modified with a K80A knock-in (KI) missense change that abolishes its GTPase activity, whereas its binding partner Reep1 is knocked out. Atl1KI/KI/Reep1-/- mice exhibit early onset and rapidly progressive declines in several motor function tests. Also, ER in mutant corticospinal axons dramatically expands transversely and periodically in a mutation dosage-dependent manner to create a ladder-like appearance, on the basis of reconstructions of focused ion beam-scanning electron microscopy datasets using machine learning-based auto-segmentation. In lockstep with changes in ER morphology, axonal mitochondria are fragmented and proportions of hypophosphorylated neurofilament H and M subunits are dramatically increased in Atl1KI/KI/Reep1-/- spinal cord. Co-occurrence of these findings links ER morphology changes to alterations in mitochondrial morphology and cytoskeletal organization. Atl1KI/KI/Reep1-/- mice represent an early onset rodent HSP model with robust behavioral and cellular readouts for testing novel therapies.
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Affiliation(s)
- Peng-Peng Zhu
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hui-Fang Hung
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
- MassGeneral Institute for Neurodegenerative Disease, Charlestown, MA 02129, USA
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Natalia Batchenkova
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jonathon Nixon-Abell
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA 20147, USA
- Cambridge Institute for Medical Research, Cambridge CB2 0XY, UK
| | - James Henderson
- Cambridge Institute for Medical Research, Cambridge CB2 0XY, UK
| | - Pengli Zheng
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
- MassGeneral Institute for Neurodegenerative Disease, Charlestown, MA 02129, USA
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Benoit Renvoisé
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Song Pang
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA 20147, USA
| | - C Shan Xu
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA 20147, USA
| | - Stephan Saalfeld
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA 20147, USA
| | - Jan Funke
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA 20147, USA
| | - Yuxiang Xie
- Synaptic Function Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Fabian Svara
- ariadne.ai ag, CH-6033 Buchrain, Switzerland
- Research Center Caesar, D-53175 Bonn, Germany
| | - Harald F Hess
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA 20147, USA
| | - Craig Blackstone
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
- MassGeneral Institute for Neurodegenerative Disease, Charlestown, MA 02129, USA
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
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13
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Shimozono K, Nan H, Hata T, Saito K, Kim YJ, Nagatomo H, Ohtsuka T, Koizumi S, Takiyama Y. Ubap1 knock-in mice reproduced the phenotype of SPG80. J Hum Genet 2022. [PMID: 35962060 DOI: 10.1038/s10038-022-01073-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 07/03/2022] [Accepted: 07/28/2022] [Indexed: 11/08/2022]
Abstract
SPG80 is a neurodegenerative disorder characterized by a pure type of juvenile-onset hereditary spastic paraplegia and is caused by a heterozygous mutation of the UBAP1 (ubiquitin-associated protein 1) gene. UBAP1 is one of the subunits of the endosomal sorting complex required for transport I and plays a role in endosome sorting by binding to ubiquitin-tagged proteins. In this study, we generated novel Ubap1+/E176Efx23 knock-in mice, in which the SOUBA domain of Ubap1 was completely deleted with the UMA domain being intact, as an animal model of SPG80. The knock-in mice with this heterozygous Ubap1 truncated mutation appeared normal at birth, but they developed progressive hind limb dysfunction several months later. Molecular pathologically, loss of neurons in the spinal cord and accumulation of ubiquitinated proteins were observed in Ubap1+/E176Efx23 knock-in mice. In addition, changes in the distributions of Rab5 and Rab7 in the spinal cord suggest that this mutation in Ubap1 disturbs endosome-mediated vesicular trafficking. This is the first report of a mouse model that reproduces the phenotype of SPG80. Our knock-in mice may provide a clue for understanding the molecular pathogenesis underlying UBAP1-related HSP and screening of therapeutic agents.
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14
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Halder D, Jeon SJ, Yoon JY, Lee JJ, Jun SY, Choi MH, Jeong B, Sung DH, Lee DY, Kim BJ, Kim NS. TREX1 Deficiency Induces ER Stress-Mediated Neuronal Cell Death by Disrupting Ca 2+ Homeostasis. Mol Neurobiol 2022. [PMID: 34997539 DOI: 10.1007/s12035-021-02631-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 11/01/2021] [Indexed: 11/09/2022]
Abstract
TREX1 is an exonuclease that degrades extranuclear DNA species in mammalian cells. Herein, we show a novel mechanism by which TREX1 interacts with the BiP/GRP78 and TREX1 deficiency triggers ER stress through the accumulation of single-stranded DNA and activates unfolded protein response (UPR) signaling via the disruption of the TREX1-BiP/GRP78 interaction. In TREX1 knockdown cells, the activation of ER stress signaling disrupted ER Ca2+ homeostasis via the ERO1α-IP3R1-CaMKII pathway, leading to neuronal cell death. Moreover, TREX1 knockdown dysregulated the Golgi-microtubule network through Golgi fragmentation and decreased Ac-α-tubulin levels, contributing to neuronal injury. These alterations were also observed in neuronal cells harboring a TREX1 mutation (V91M) that has been identified in hereditary spastic paraplegia (HSP) patients in Korea. Notably, this mutation leads to defects in the TREX1-BiP/GRP78 interaction and mislocalization of TREX1 from the ER and possible disruption of the Golgi-microtubule network. In summary, the current study reveals TREX1 as a novel regulator of the BiP/GRP78 interaction and shows that TREX1 deficiency promotes ER stress-mediated neuronal cell death, which indicates that TREX1 may hold promise as a therapeutic target for neurodegenerative diseases such as HSP.
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15
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Sonda S, Pendin D, Daga A. ER Morphology in the Pathogenesis of Hereditary Spastic Paraplegia. Cells 2021; 10:2870. [PMID: 34831093 DOI: 10.3390/cells10112870] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 10/18/2021] [Accepted: 10/20/2021] [Indexed: 12/18/2022] Open
Abstract
The endoplasmic reticulum (ER) is the most abundant and widespread organelle in cells. Its peculiar membrane architecture, formed by an intricate network of tubules and cisternae, is critical to its multifaceted function. Regulation of ER morphology is coordinated by a few ER-specific membrane proteins and is thought to be particularly important in neurons, where organized ER membranes are found even in the most distant neurite terminals. Mutation of ER-shaping proteins has been implicated in the neurodegenerative disease hereditary spastic paraplegia (HSP). In this review we discuss the involvement of these proteins in the pathogenesis of HSP, focusing on the experimental evidence linking their molecular function to disease onset. Although the precise biochemical activity of some ER-related HSP proteins has been elucidated, the pathological mechanism underlying ER-linked HSP is still undetermined and needs to be further investigated.
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16
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Darios F, Coarelli G, Durr A. Genetics in hereditary spastic paraplegias: Essential but not enough. Curr Opin Neurobiol 2021; 72:8-14. [PMID: 34403957 DOI: 10.1016/j.conb.2021.07.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 06/04/2021] [Accepted: 07/14/2021] [Indexed: 12/01/2022]
Abstract
Hereditary spastic paraplegias consist of a group of rare neurodegenerative diseases characterized by lower limb spasticity. These inherited Mendelian disorders show high genetic variability associated with wide clinical diversity. Pathophysiological investigations have suggested that mutations in genes affecting the same cellular pathway generally lead to similar clinical symptoms, highlighting the importance of genetic mutation in these diseases. However, phenotype-genotype correlations have failed to explain the observed large inter-individual variability linked to mutations in a single gene, suggesting that genetics alone is not sufficient to explain symptom diversity. The identification of biomarkers, such as neurofilament light chain, could fill the gap and predict disease evolution.
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Affiliation(s)
- Frédéric Darios
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm U1127, CNRS UMR7225, Paris, 75013, France.
| | - Giulia Coarelli
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm U1127, CNRS UMR7225, Paris, 75013, France; AP-HP, Hôpital de la Pitié Salpêtrière, Paris, 75013, France
| | - Alexandra Durr
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, Inserm U1127, CNRS UMR7225, Paris, 75013, France; AP-HP, Hôpital de la Pitié Salpêtrière, Paris, 75013, France.
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17
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Liang Q, Wu N, Zaneveld S, Liu H, Fu S, Wang K, Bertrand R, Wang J, Li Y, Chen R. Transcript isoforms of Reep6 have distinct functions in the retina. Hum Mol Genet 2021; 30:1907-1918. [PMID: 34104971 DOI: 10.1093/hmg/ddab157] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/30/2021] [Accepted: 05/31/2021] [Indexed: 12/21/2022] Open
Abstract
Much of the complexity of the eukaryotic cell transcriptome is due to the alternative splicing of mRNA. However, knowledge on how transcriptome complexity is translated into functional complexity remains limited. For example, although different isoforms of a gene may show distinct temporal and spatial expression patterns, it is largely unknown whether these isoforms encode proteins with distinct functions matching their expression pattern. In this report, we investigated the function and relationship of the two isoforms of Reep6, namely Reep6.1 and Reep6.2, in rod photoreceptor cells. These two isoforms result from the alternative splicing of exon 5 and show mutually exclusive expression patterns. Reep6.2 is the canonical isoform that is expressed in non-retinal tissues while Reep6.1 is the only expressed isoform in the adult retina. The Reep6.1 isoform-specific knockout mouse, Reep6E5/E5, is generated by deleting exon 5 and a homozygous deletion phenotypically displayed a rod degeneration phenotype comparable to a Reep6 full knockout mouse, indicating that the Reep6.1 isoform is essential for the rod photoreceptor cell survival. Consistent with the results obtained from a loss-of-function experiment, overexpression of Reep6.2 failed to rescue the rod degeneration phenotype of Reep6 knockout mice while overexpression of Reep6.1 does lead to rescue. These results demonstrate that, consistent with the expression pattern of the isoform, Reep6.1 has rod-specific functions that cannot be substituted by its canonical isoform. Our findings suggested that a strict regulation of splicing is required for the maintenance of photoreceptor cells.
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Affiliation(s)
- Qingnan Liang
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA.,Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Nathaniel Wu
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Smriti Zaneveld
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Hehe Liu
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Shangyi Fu
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Keqing Wang
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Renae Bertrand
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA.,Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Jun Wang
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Yumei Li
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA
| | - Rui Chen
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, 77030, USA.,Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, 77030, USA
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18
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Franzka P, Henze H, Jung MJ, Schüler SC, Mittag S, Biskup K, Liebmann L, Kentache T, Morales J, Martínez B, Katona I, Herrmann T, Huebner AK, Hennings JC, Groth S, Gresing L, Horstkorte R, Marquardt T, Weis J, Kaether C, Mutchinick OM, Ori A, Huber O, Blanchard V, von Maltzahn J, Hübner CA. GMPPA defects cause a neuromuscular disorder with α-dystroglycan hyperglycosylation. J Clin Invest 2021; 131:139076. [PMID: 33755596 DOI: 10.1172/jci139076] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 03/18/2021] [Indexed: 11/17/2022] Open
Abstract
GDP-mannose-pyrophosphorylase-B (GMPPB) facilitates the generation of GDP-mannose, a sugar donor required for glycosylation. GMPPB defects cause muscle disease due to hypoglycosylation of α-dystroglycan (α-DG). Alpha-DG is part of a protein complex, which links the extracellular matrix with the cytoskeleton, thus stabilizing myofibers. Mutations of the catalytically inactive homolog GMPPA cause alacrima, achalasia, and mental retardation syndrome (AAMR syndrome), which also involves muscle weakness. Here, we showed that Gmppa-KO mice recapitulated cognitive and motor deficits. As structural correlates, we found cortical layering defects, progressive neuron loss, and myopathic alterations. Increased GDP-mannose levels in skeletal muscle and in vitro assays identified GMPPA as an allosteric feedback inhibitor of GMPPB. Thus, its disruption enhanced mannose incorporation into glycoproteins, including α-DG in mice and humans. This increased α-DG turnover and thereby lowered α-DG abundance. In mice, dietary mannose restriction beginning after weaning corrected α-DG hyperglycosylation and abundance, normalized skeletal muscle morphology, and prevented neuron degeneration and the development of motor deficits. Cortical layering and cognitive performance, however, were not improved. We thus identified GMPPA defects as the first congenital disorder of glycosylation characterized by α-DG hyperglycosylation, to our knowledge, and we have unraveled underlying disease mechanisms and identified potential dietary treatment options.
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Affiliation(s)
- Patricia Franzka
- Institute of Human Genetics, University Hospital Jena, Friedrich Schiller University, Jena, Germany
| | - Henriette Henze
- Leibniz-Institute on Aging - Fritz-Lipmann-Institute, Jena, Germany
| | - M Juliane Jung
- Leibniz-Institute on Aging - Fritz-Lipmann-Institute, Jena, Germany
| | | | - Sonnhild Mittag
- Department of Biochemistry II, University Hospital Jena, Friedrich Schiller University, Jena, Germany
| | - Karina Biskup
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Berlin, Germany
| | - Lutz Liebmann
- Institute of Human Genetics, University Hospital Jena, Friedrich Schiller University, Jena, Germany
| | - Takfarinas Kentache
- Welbio and de Duve Institute, Université Catholique de Louvain, Brussels, Belgium
| | - José Morales
- Department of Genetics, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Braulio Martínez
- Department of Pathology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Istvan Katona
- Institut für Neuropathologie, Institute of Neuropathology, RWTH Aachen University Hospital, Aachen, Germany
| | - Tanja Herrmann
- Institute of Human Genetics, University Hospital Jena, Friedrich Schiller University, Jena, Germany
| | - Antje-Kathrin Huebner
- Institute of Human Genetics, University Hospital Jena, Friedrich Schiller University, Jena, Germany
| | - J Christopher Hennings
- Institute of Human Genetics, University Hospital Jena, Friedrich Schiller University, Jena, Germany
| | - Susann Groth
- Leibniz-Institute on Aging - Fritz-Lipmann-Institute, Jena, Germany
| | - Lennart Gresing
- Institute of Human Genetics, University Hospital Jena, Friedrich Schiller University, Jena, Germany
| | - Rüdiger Horstkorte
- Institut für Physiologische Chemie, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
| | - Thorsten Marquardt
- University Hospital Muenster, Department of Pediatrics, Muenster, Germany
| | - Joachim Weis
- Institut für Neuropathologie, Institute of Neuropathology, RWTH Aachen University Hospital, Aachen, Germany
| | | | - Osvaldo M Mutchinick
- Department of Genetics, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Alessandro Ori
- Leibniz-Institute on Aging - Fritz-Lipmann-Institute, Jena, Germany
| | - Otmar Huber
- Department of Biochemistry II, University Hospital Jena, Friedrich Schiller University, Jena, Germany
| | - Véronique Blanchard
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Berlin, Germany
| | | | - Christian A Hübner
- Institute of Human Genetics, University Hospital Jena, Friedrich Schiller University, Jena, Germany
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19
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Sree S, Parkkinen I, Their A, Airavaara M, Jokitalo E. Morphological Heterogeneity of the Endoplasmic Reticulum within Neurons and Its Implications in Neurodegeneration. Cells 2021; 10:970. [PMID: 33919188 DOI: 10.3390/cells10050970] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 04/13/2021] [Accepted: 04/19/2021] [Indexed: 12/19/2022] Open
Abstract
The endoplasmic reticulum (ER) is a multipurpose organelle comprising dynamic structural subdomains, such as ER sheets and tubules, serving to maintain protein, calcium, and lipid homeostasis. In neurons, the single ER is compartmentalized with a careful segregation of the structural subdomains in somatic and neurite (axodendritic) regions. The distribution and arrangement of these ER subdomains varies between different neuronal types. Mutations in ER membrane shaping proteins and morphological changes in the ER are associated with various neurodegenerative diseases implying significance of ER morphology in maintaining neuronal integrity. Specific neurons, such as the highly arborized dopaminergic neurons, are prone to stress and neurodegeneration. Differences in morphology and functionality of ER between the neurons may account for their varied sensitivity to stress and neurodegenerative changes. In this review, we explore the neuronal ER and discuss its distinct morphological attributes and specific functions. We hypothesize that morphological heterogeneity of the ER in neurons is an important factor that accounts for their selective susceptibility to neurodegeneration.
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20
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Morikawa T, Ohishi H, Kosaka K, Shimojo T, Nagano A, Taniguchi I, Fujioka R, Moriyama K, Unoki M, Takahashi M, Nakao M, Izumi Y, Bamba T, Sasaki H, Miura S, Shibata H. Ddhd1 knockout mouse as a model of locomotive and physiological abnormality in familial spastic paraplegia. Biosci Rep 2021; 41:BSR20204171. [PMID: 33600578 DOI: 10.1042/BSR20204171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 02/04/2021] [Accepted: 02/11/2021] [Indexed: 11/17/2022] Open
Abstract
We have previously reported a novel homozygous 4-bp deletion in DDHD1 as the responsible variant for spastic paraplegia type 28 (SPG28; OMIM#609340). The variant causes a frameshift, resulting in a functionally null allele in the patient. DDHD1 encodes phospholipase A1 (PLA1) catalyzing phosphatidylinositol to lysophosphatidylinositol (LPI). To clarify the pathogenic mechanism of SPG28, we established Ddhd1 knockout mice (Ddhd1[-/-]) carrying a 5-bp deletion in Ddhd1, resulting in a premature termination of translation at a position similar to that of the patient. We observed a significant decrease in foot-base angle (FBA) in aged Ddhd1(-/-) (24 months of age) and a significant decrease in LPI 20:4 (sn-2) in Ddhd1(-/-) cerebra (26 months of age). These changes in FBA were not observed in 14 months of age. We also observed significant changes of expression levels of 22 genes in the Ddhd1(-/-) cerebra (26 months of age). Gene Ontology (GO) terms relating to the nervous system and cell-cell communications were significantly enriched. We conclude that the reduced signaling of LPI 20:4 (sn-2) by PLA1 dysfunction is responsible for the locomotive abnormality in SPG28, further suggesting that the reduction of downstream signaling such as GPR55 which is agonized by LPI is involved in the pathogenesis of SPG28.
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21
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Edmison D, Wang L, Gowrishankar S. Lysosome Function and Dysfunction in Hereditary Spastic Paraplegias. Brain Sci 2021; 11:152. [PMID: 33498913 PMCID: PMC7911997 DOI: 10.3390/brainsci11020152] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/15/2021] [Accepted: 01/21/2021] [Indexed: 12/13/2022] Open
Abstract
Hereditary Spastic Paraplegias (HSPs) are a genetically diverse group of inherited neurological diseases with over 80 associated gene loci. Over the last decade, research into mechanisms underlying HSPs has led to an emerging interest in lysosome dysfunction. In this review, we highlight the different classes of HSPs that have been linked to lysosome defects: (1) a subset of complex HSPs where mutations in lysosomal genes are causally linked to the diseases, (2) other complex HSPs where mutation in genes encoding membrane trafficking adaptors lead to lysosomal defects, and (3) a subset of HSPs where mutations affect genes encoding proteins whose function is primarily linked to a different cellular component or organelle such as microtubule severing and Endoplasmic Reticulum-shaping, while also altering to lysosomes. Interestingly, aberrant axonal lysosomes, associated with the latter two subsets of HSPs, are a key feature observed in other neurodegenerative diseases such as Alzheimer's disease. We discuss how altered lysosome function and trafficking may be a critical contributor to HSP pathology and highlight the need for examining these features in the cortico-spinal motor neurons of HSP mutant models.
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Affiliation(s)
| | | | - Swetha Gowrishankar
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA; (D.E.); (L.W.)
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Kozono T, Sato H, Okumura W, Jogano C, Tamura-Nakano M, Kawamura YI, Rohrer J, Tonozuka T, Nishikawa A. The N-terminal region of Jaw1 has a role to inhibit the formation of organized smooth endoplasmic reticulum as an intrinsically disordered region. Sci Rep 2021; 11:753. [PMID: 33436890 PMCID: PMC7804115 DOI: 10.1038/s41598-020-80258-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 12/18/2020] [Indexed: 02/07/2023] Open
Abstract
Jaw1/LRMP is a type II integral membrane protein that is localized at the endoplasmic reticulum (ER) and outer nuclear membrane. We previously reported that a function of Jaw1 is to maintain the nuclear shape as a KASH protein via its carboxyl terminal region, a component of linker of nucleoskeleton and cytoskeleton complex in the oligomeric state. Although the oligomerization of some KASH proteins via the cytosolic regions serves to stabilize protein-protein interactions, the issue of how the oligomerization of Jaw1 is regulated is not completely understood. Therefore, we focused on three distinct regions on the cytosolic face of Jaw1: the N-terminal region, the coiled-coil domain and the stem region, in terms of oligomerization. A co-immunoprecipitation assay showed that its coiled-coil domain is a candidate for the oligomerization site. Furthermore, our data indicated that the N-terminal region prevents the aberrant oligomerization of Jaw1 as an intrinsically disordered region (IDR). Importantly, the ectopic expression of an N-terminal region deleted mutant caused the formation of organized smooth ER (OSER), structures such as nuclear karmellae and whorls, in B16F10 cells. Furthermore, this OSER interfered with the localization of the oligomer and interactors such as the type III inositol 1,4,5-triphosphate receptor (IP3R3) and SUN2. In summary, the N-terminal region of Jaw1 inhibits the formation of OSER as an IDR to maintain the homeostatic localization of interactors on the ER membrane.
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Affiliation(s)
- Takuma Kozono
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Tokyo, 183-8509, Japan.,Department of Gastroenterology, The Research Center for Hepatitis and Immunology, Research Institute, National Center for Global Health and Medicine, Chiba, 272-8516, Japan
| | - Hiroyuki Sato
- Department of Applied Biological Chemistry, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, 183-8509, Japan
| | - Wataru Okumura
- Department of Food and Energy Systems Science, Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Tokyo, 184-8588, Japan
| | - Chifuyu Jogano
- Department of Applied Biological Chemistry, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, 183-8509, Japan
| | - Miwa Tamura-Nakano
- Communal Laboratory, Research Institute, National Center for Global Health and Medicine, Tokyo, 162-8655, Japan
| | - Yuki I Kawamura
- Department of Gastroenterology, The Research Center for Hepatitis and Immunology, Research Institute, National Center for Global Health and Medicine, Chiba, 272-8516, Japan
| | - Jack Rohrer
- Institute of Chemistry and Biotechnology, Zurich University of Applied Sciences, CH-8820, Waedenswil, Switzerland
| | - Takashi Tonozuka
- Department of Applied Biological Chemistry, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, 183-8509, Japan
| | - Atsushi Nishikawa
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Tokyo, 183-8509, Japan. .,Department of Applied Biological Chemistry, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, 183-8509, Japan. .,Department of Food and Energy Systems Science, Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Tokyo, 184-8588, Japan.
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23
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Wang B, Yu Y, Wei L, Zhang Y. Inhibition of ER stress improves progressive motor deficits in a REEP1-null mouse model of hereditary spastic paraplegia. Biol Open 2020; 9:bio054296. [PMID: 32878877 PMCID: PMC7541344 DOI: 10.1242/bio.054296] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 08/26/2020] [Indexed: 01/06/2023] Open
Abstract
Hereditary spastic paraplegias (HSPs) are genetic neurodegenerative diseases. HSPs are characterized by lower-extremity weakness and spasticity. However, there is no specific clinical treatment strategy to prevent or reverse nerve degeneration in HSPs. Mutations in receptor expression-enhancing protein 1 (REEP1) are well-recognized and relatively common causes of autosomal dominant HSPs. REEP1 modifies the endoplasmic reticulum (ER) shape, and is implicated in the ER stress response. Defects in the ER stress response seem to be crucial mechanisms underlying HSP neurodegeneration. Here, we report that REEP1-/- mice exhibit progressive motor deficits, along with denervation of neuromuscular junctions and increased ER stress. Moreover, marked axonal degeneration and morphological abnormalities are observed. In this study, we treated both REEP1-/- and wild-type (WT) mice with salubrinal, which is a specific inhibitor of ER stress, and we observed increased nerve-muscle connections and enhanced motor functions. Our data highlight the importance of ER homeostasis in HSPs, providing new opportunities for HSP treatment.
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Affiliation(s)
- Bingjie Wang
- State Key Laboratory of Membrane Biology, School of Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - You Yu
- State Key Laboratory of Membrane Biology, School of Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Lai Wei
- State Key Laboratory of Membrane Biology, School of Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Yan Zhang
- State Key Laboratory of Membrane Biology, School of Life Sciences, PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
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24
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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25
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Abstract
Background: REEP1 is a common cause of autosomal dominant hereditary spastic paraplegia (HSP) but is rare in China. The pathological mechanism of REEP1 is not fully understood. Methods: We screened for REEP1 mutations in 31 unrelated probands from Chinese HSP families using next-generation sequencing targeting pathogenic genes for HSP and other related diseases. All variants were validated by Sanger sequencing. The proband family members were also screened for variants for the segregation analysis. All previously reported REEP1 mutations and cases were reviewed to clarify the genetic and clinical features of REEP1-related HSP. Results: A pathogenic mutation, REEP1c. 125G>A (p.Trp42*), was detected in a pure HSP family from North China out of 31 HSP families (1/31). This locus, which is located in the second hydrophobic domain of REEP1, is detected in both Caucasian patients with complicated HSP phenotypes and Chinese pure HSP families. Conclusion: REEP1-related HSP can be found in the Chinese population. The 42nd residue is a novel transethnic mutation hotspot. Mutations in this spot can lead to both complicated and pure form of HSP. Identification of transethnic hotspot will contribute to clarify the underlying pathological mechanisms.
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Affiliation(s)
- Xinran Ma
- Department of Neurology, Peking University Third Hospital, Beijing, China
| | - Ji He
- Department of Neurology, Peking University Third Hospital, Beijing, China
| | - Xiaoxuan Liu
- Department of Neurology, Peking University Third Hospital, Beijing, China
| | - Dongsheng Fan
- Department of Neurology, Peking University Third Hospital, Beijing, China.,Beijing Municipal Key Laboratory of Biomarker and Translational Research in Neurodegenerative Diseases, Beijing, China.,Key Laboratory for Neuroscience, National Health Commission/Ministry of Education, Peking University, Beijing, China
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26
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Guglielmi A. A complete overview of REEP1: old and new insights on its role in hereditary spastic paraplegia and neurodegeneration. Rev Neurosci 2020; 31:351-362. [PMID: 31913854 DOI: 10.1515/revneuro-2019-0083] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 11/08/2019] [Indexed: 01/09/2023]
Abstract
At the end of 19th century, Adolf von Strümpell and Sigmund Freud independently described the symptoms of a new pathology now known as hereditary spastic paraplegia (HSP). HSP is part of the group of genetic neurodegenerative diseases usually associated with slow progressive pyramidal syndrome, spasticity, weakness of the lower limbs, and distal-end degeneration of motor neuron long axons. Patients are typically characterized by gait symptoms (with or without other neurological disorders), which can appear both in young and adult ages depending on the different HSP forms. The disease prevalence is at 1.3-9.6 in 100 000 individuals in different areas of the world, making HSP part of the group of rare neurodegenerative diseases. Thus far, there are no specific clinical and paraclinical tests, and DNA analysis is still the only strategy to obtain a certain diagnosis. For these reasons, it is mandatory to extend the knowledge on genetic causes, pathology mechanism, and disease progression to give clinicians more tools to obtain early diagnosis, better therapeutic strategies, and examination tests. This review gives an overview of HSP pathologies and general insights to a specific HSP subtype called spastic paraplegia 31 (SPG31), which rises after mutation of REEP1 gene. In fact, recent findings discovered an interesting endoplasmic reticulum antistress function of REEP1 and a role of this protein in preventing τ accumulation in animal models. For this reason, this work tries to elucidate the main aspects of REEP1, which are described in the literature, to better understand its role in SPG31 HSP and other pathologies.
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Affiliation(s)
- Alessio Guglielmi
- Neurobiology Laboratory, International Centre of Genetic Engineering and Biotechnology, I-34149 Trieste, Italy
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27
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Arribat Y, Grepper D, Lagarrigue S, Qi T, Cohen S, Amati F. Spastin mutations impair coordination between lipid droplet dispersion and reticulum. PLoS Genet 2020; 16:e1008665. [PMID: 32315314 DOI: 10.1371/journal.pgen.1008665] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Accepted: 02/12/2020] [Indexed: 12/22/2022] Open
Abstract
Lipid droplets (LD) are affected in multiple human disorders. These highly dynamic organelles are involved in many cellular roles. While their intracellular dispersion is crucial to ensure their function and other organelles-contact, underlying mechanisms are still unclear. Here we show that Spastin, one of the major proteins involved in Hereditary Spastic Paraplegia (HSP), controls LD dispersion. Spastin depletion in zebrafish affects metabolic properties and organelle dynamics. These functions are ensured by a conserved complex set of splice variants. M1 isoforms determine LD dispersion in the cell by orchestrating endoplasmic reticulum (ER) shape along microtubules (MTs). To further impact LD fate, Spastin modulates transcripts levels and subcellular location of other HSP key players, notably Seipin and REEP1. In pathological conditions, mutations in human Spastin M1 disrupt this mechanism and impacts LD network. Spastin depletion influences not only other key proteins but also modulates specific neutral lipids and phospholipids, revealing an impact on membrane and organelle components. Altogether our results show that Spastin and its partners converge in a common machinery that coordinates LD dispersion and ER shape along MTs. Any alteration of this system results in HSP clinical features and impacts lipids profile, thus opening new avenues for novel biomarkers of HSP.
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28
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Lee SH, Hadipour-Lakmehsari S, Murthy HR, Gibb N, Miyake T, Teng ACT, Cosme J, Yu JC, Moon M, Lim S, Wong V, Liu P, Billia F, Fernandez-Gonzalez R, Stagljar I, Sharma P, Kislinger T, Scott IC, Gramolini AO. REEP5 depletion causes sarco-endoplasmic reticulum vacuolization and cardiac functional defects. Nat Commun 2020; 11:965. [PMID: 32075961 DOI: 10.1038/s41467-019-14143-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 12/17/2019] [Indexed: 12/17/2022] Open
Abstract
The sarco-endoplasmic reticulum (SR/ER) plays an important role in the development and progression of many heart diseases. However, many aspects of its structural organization remain largely unknown, particularly in cells with a highly differentiated SR/ER network. Here, we report a cardiac enriched, SR/ER membrane protein, REEP5 that is centrally involved in regulating SR/ER organization and cellular stress responses in cardiac myocytes. In vitro REEP5 depletion in mouse cardiac myocytes results in SR/ER membrane destabilization and luminal vacuolization along with decreased myocyte contractility and disrupted Ca2+ cycling. Further, in vivo CRISPR/Cas9-mediated REEP5 loss-of-function zebrafish mutants show sensitized cardiac dysfunction upon short-term verapamil treatment. Additionally, in vivo adeno-associated viral (AAV9)-induced REEP5 depletion in the mouse demonstrates cardiac dysfunction. These results demonstrate the critical role of REEP5 in SR/ER organization and function as well as normal heart function and development. The sarcoplasmic (SR) and endoplasmic reticulum (ER) are involved in heart development but how this arises is unclear. Here, the authors show that loss of a SR/ER protein REEP5 causes membrane destabilization and decreased cardiac myocyte contractility, with cardiac dysfunction in mutant mouse and zebrafish models.
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29
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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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30
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Napoli B, Gumeni S, Forgiarini A, Fantin M, De Filippis C, Panzeri E, Vantaggiato C, Orso G. Naringenin Ameliorates Drosophila ReepA Hereditary Spastic Paraplegia-Linked Phenotypes. Front Neurosci 2019; 13:1202. [PMID: 31803000 PMCID: PMC6877660 DOI: 10.3389/fnins.2019.01202] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 10/23/2019] [Indexed: 12/11/2022] Open
Abstract
Defects in the endoplasmic reticulum (ER) membrane shaping and interaction with other organelles seem to be a crucial mechanism underlying Hereditary Spastic Paraplegia (HSP) neurodegeneration. REEP1, a transmembrane protein belonging to TB2/HVA22 family, is implicated in SPG31, an autosomal dominant form of HSP, and its interaction with Atlastin/SPG3A and Spastin/SPG4, the other two major HSP linked proteins, has been demonstrated to play a crucial role in modifying ER architecture. In addition, the Drosophila ortholog of REEP1, named ReepA, has been found to regulate the response to ER neuronal stress. Herein we investigated the role of ReepA in ER morphology and stress response. ReepA is upregulated under stress conditions and aging. Our data show that ReepA triggers a selective activation of Ire1 and Atf6 branches of Unfolded Protein Response (UPR) and modifies ER morphology. Drosophila lacking ReepA showed Atf6 and Ire1 activation, expansion of ER sheet-like structures, locomotor dysfunction and shortened lifespan. Furthermore, we found that naringenin, a flavonoid that possesses strong antioxidant and neuroprotective activity, can rescue the cellular phenotypes, the lifespan and locomotor disability associated with ReepA loss of function. Our data highlight the importance of ER homeostasis in nervous system functionality and HSP neurodegenerative mechanisms, opening new opportunities for HSP treatment.
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Affiliation(s)
- Barbara Napoli
- Scientific Institute, IRCCS Eugenio Medea, Laboratory of Molecular Biology, Bosisio Parini, Lecco, Italy
| | - Sentiljana Gumeni
- Department of Cell Biology and Biophysics, Faculty of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Alessia Forgiarini
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padova, Italy
| | - Marianna Fantin
- Scientific Institute, IRCCS Eugenio Medea, Laboratory of Molecular Biology, Bosisio Parini, Lecco, Italy
| | - Concetta De Filippis
- Foundation Institute of Pediatric Research, “Città della Speranza”, Padova, Italy
| | - Elena Panzeri
- Scientific Institute, IRCCS Eugenio Medea, Laboratory of Molecular Biology, Bosisio Parini, Lecco, Italy
| | - Chiara Vantaggiato
- Scientific Institute, IRCCS Eugenio Medea, Laboratory of Molecular Biology, Bosisio Parini, Lecco, Italy
| | - Genny Orso
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, Padova, Italy
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31
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Abstract
Autophagy regulates the degradation of unnecessary or dysfunctional cellular components. This catabolic process requires the formation of a double-membrane vesicle, the autophagosome, that engulfs the cytosolic material and delivers it to the lysosome. Substrate specificity is achieved by autophagy receptors, which are characterized by the presence of at least one LC3-interaction region (LIR) or GABARAP-interaction motif (GIM). Only recently, several receptors that mediate the specific degradation of endoplasmic reticulum (ER) components via autophagy have been identified (the process known as ER-phagy or reticulophagy). Here, we give an update on the current knowledge about the role of ER-phagy receptors in health and disease.
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32
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Fowler PC, Garcia-Pardo ME, Simpson JC, O'Sullivan NC. NeurodegenERation: The Central Role for ER Contacts in Neuronal Function and Axonopathy, Lessons From Hereditary Spastic Paraplegias and Related Diseases. Front Neurosci 2019; 13:1051. [PMID: 31680803 PMCID: PMC6801308 DOI: 10.3389/fnins.2019.01051] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 09/19/2019] [Indexed: 12/17/2022] Open
Abstract
The hereditary spastic paraplegias (HSPs) are a group of inherited neurodegenerative conditions whose characteristic feature is degeneration of the longest axons within the corticospinal tract which leads to progressive spasticity and weakness of the lower limbs. Though highly genetically heterogeneous, the majority of HSP cases are caused by mutations in genes encoding proteins that are responsible for generating and organizing the tubular endoplasmic reticulum (ER). Despite this, the role of the ER within neurons, particularly the long axons affected in HSP, is not well understood. Throughout axons, ER tubules make extensive contacts with other organelles, the cytoskeleton and the plasma membrane. At these ER contacts, protein complexes work in concert to perform specialized functions including organelle shaping, calcium homeostasis and lipid biogenesis, all of which are vital for neuronal survival and may be disrupted by HSP-causing mutations. In this article we summarize the proteins which mediate ER contacts, review the functions these contacts are known to carry out within neurons, and discuss the potential contribution of disruption of ER contacts to axonopathy in HSP.
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Affiliation(s)
- Philippa C Fowler
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - M Elena Garcia-Pardo
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Jeremy C Simpson
- UCD School of Biology and Environmental Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Niamh C O'Sullivan
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
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33
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Wolf D, Hofbrucker-MacKenzie SA, Izadi M, Seemann E, Steiniger F, Schwintzer L, Koch D, Kessels MM, Qualmann B. Ankyrin repeat-containing N-Ank proteins shape cellular membranes. Nat Cell Biol 2019; 21:1191-1205. [PMID: 31548610 DOI: 10.1038/s41556-019-0381-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 07/25/2019] [Indexed: 01/02/2023]
Abstract
Cells of multicellular organisms need to adopt specific morphologies. However, the molecular mechanisms bringing about membrane topology changes are far from understood-mainly because knowledge of membrane-shaping proteins that can promote local membrane curvatures is still limited. Our analyses unveiled that several members of a large, previously unrecognised protein family, which we termed N-Ank proteins, use a combination of their ankyrin repeat array and an amino (N)-terminal amphipathic helix to bind and shape membranes. Consistently, functional analyses revealed that the N-Ank protein ankycorbin (NORPEG/RAI14), which was exemplarily characterised further, plays an important, ankyrin repeat-based and N-terminal amphipathic helix-dependent role in early morphogenesis of neurons. This function furthermore required coiled coil-mediated self-assembly and manifested as ankycorbin nanodomains marked by protrusive membrane topologies. In summary, here, we unveil a class of powerful membrane shapers and thereby assign mechanistic and cell biological functions to the N-Ank protein superfamily.
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Affiliation(s)
- David Wolf
- Institute of Biochemistry I, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | | | - Maryam Izadi
- Institute of Biochemistry I, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Eric Seemann
- Institute of Biochemistry I, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Frank Steiniger
- Electron Microscopy Centre, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Lukas Schwintzer
- Institute of Biochemistry I, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Dennis Koch
- Institute of Biochemistry I, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Michael Manfred Kessels
- Institute of Biochemistry I, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany.
| | - Britta Qualmann
- Institute of Biochemistry I, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany.
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Genc B, Gozutok O, Ozdinler PH. Complexity of Generating Mouse Models to Study the Upper Motor Neurons: Let Us Shift Focus from Mice to Neurons. Int J Mol Sci 2019; 20:E3848. [PMID: 31394733 DOI: 10.3390/ijms20163848] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 07/26/2019] [Accepted: 08/05/2019] [Indexed: 12/11/2022] Open
Abstract
Motor neuron circuitry is one of the most elaborate circuitries in our body, which ensures voluntary and skilled movement that requires cognitive input. Therefore, both the cortex and the spinal cord are involved. The cortex has special importance for motor neuron diseases, in which initiation and modulation of voluntary movement is affected. Amyotrophic lateral sclerosis (ALS) is defined by the progressive degeneration of both the upper and lower motor neurons, whereas hereditary spastic paraplegia (HSP) and primary lateral sclerosis (PLS) are characterized mainly by the loss of upper motor neurons. In an effort to reveal the cellular and molecular basis of neuronal degeneration, numerous model systems are generated, and mouse models are no exception. However, there are many different levels of complexities that need to be considered when developing mouse models. Here, we focus our attention to the upper motor neurons, which are one of the most challenging neuron populations to study. Since mice and human differ greatly at a species level, but the cells/neurons in mice and human share many common aspects of cell biology, we offer a solution by focusing our attention to the affected neurons to reveal the complexities of diseases at a cellular level and to improve translational efforts.
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Shribman S, Reid E, Crosby AH, Houlden H, Warner TT. Hereditary spastic paraplegia: from diagnosis to emerging therapeutic approaches. Lancet Neurol 2019; 18:1136-46. [PMID: 31377012 DOI: 10.1016/S1474-4422(19)30235-2] [Citation(s) in RCA: 147] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 05/20/2019] [Accepted: 05/29/2019] [Indexed: 12/16/2022]
Abstract
Hereditary spastic paraplegia (HSP) describes a heterogeneous group of genetic neurodegenerative diseases characterised by progressive spasticity of the lower limbs. The pathogenic mechanism, associated clinical features, and imaging abnormalities vary substantially according to the affected gene and differentiating HSP from other genetic diseases associated with spasticity can be challenging. Next generation sequencing-based gene panels are now widely available but have limitations and a molecular diagnosis is not made in most suspected cases. Symptomatic management continues to evolve but with a greater understanding of the pathophysiological basis of individual HSP subtypes there are emerging opportunities to provide targeted molecular therapies and personalised medicine.
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Khundadze M, Ribaudo F, Hussain A, Rosentreter J, Nietzsche S, Thelen M, Winter D, Hoffmann B, Afzal MA, Hermann T, de Heus C, Piskor EM, Kosan C, Franzka P, von Kleist L, Stauber T, Klumperman J, Damme M, Proikas-Cezanne T, Hübner CA. A mouse model for SPG48 reveals a block of autophagic flux upon disruption of adaptor protein complex five. Neurobiol Dis 2019; 127:419-431. [PMID: 30930081 DOI: 10.1016/j.nbd.2019.03.026] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 02/25/2019] [Accepted: 03/24/2019] [Indexed: 12/25/2022] Open
Abstract
Hereditary spastic paraplegia is a spastic gait disorder that arises from degeneration of corticospinal axons. The subtype SPG48 is associated with mutations in the zeta subunit of the adaptor protein complex five (AP5). AP5 function and the pathophysiology of SPG48 are only poorly understood. Here, we report an AP5 zeta knockout mouse, which shows an age-dependent degeneration of corticospinal axons. Our analysis of knockout fibroblasts supports a trafficking defect from late endosomes to the transGolgi network and reveals a structural defect of the Golgi. We further show that both autophagic flux and the recycling of lysosomes from autolysosomes were impaired in knockout cells. In vivo, we observe an increase of autophagosomes and autolysosomes and, at later stages, the accumulation of intracellular waste in neurons. Taken together, we propose that loss of AP5 function blocks autophagy and thus leads to the aberrant accumulation of autophagic cargo, which finally results in axon degeneration.
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Affiliation(s)
- Mukhran Khundadze
- Institute of Human Genetics, University Hospital Jena, Friedrich-Schiller-University Jena, Jena 07747, Germany.
| | - Federico Ribaudo
- Institute of Human Genetics, University Hospital Jena, Friedrich-Schiller-University Jena, Jena 07747, Germany
| | - Adeela Hussain
- Institute of Human Genetics, University Hospital Jena, Friedrich-Schiller-University Jena, Jena 07747, Germany
| | - Jan Rosentreter
- Institute of Human Genetics, University Hospital Jena, Friedrich-Schiller-University Jena, Jena 07747, Germany
| | - Sandor Nietzsche
- Electron Microscopy Center, University Hospital Jena, Friedrich-Schiller-University Jena, Jena 07743, Germany
| | - Melanie Thelen
- Institute for Biochemistry and Molecular Biology, University of Bonn, Bonn 53115, Germany
| | - Dominic Winter
- Institute for Biochemistry and Molecular Biology, University of Bonn, Bonn 53115, Germany
| | - Birgit Hoffmann
- Biomolecular Photonics Group, University Hospital Jena, Friedrich-Schiller-University Jena, Jena 07743, Germany
| | - Muhammad Awais Afzal
- Institute of Human Genetics, University Hospital Jena, Friedrich-Schiller-University Jena, Jena 07747, Germany
| | - Tanja Hermann
- Institute of Human Genetics, University Hospital Jena, Friedrich-Schiller-University Jena, Jena 07747, Germany
| | - Cecilia de Heus
- Department of Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht 3584, Netherlands
| | - Eva-Maria Piskor
- Institute of Biochemistry and Biophysics, Friedrich-Schiller-University Jena, Jena 07743, Germany
| | - Christian Kosan
- Institute of Biochemistry and Biophysics, Friedrich-Schiller-University Jena, Jena 07743, Germany
| | - Patricia Franzka
- Institute of Human Genetics, University Hospital Jena, Friedrich-Schiller-University Jena, Jena 07747, Germany
| | - Lisa von Kleist
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin 14195, Germany
| | - Tobias Stauber
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin 14195, Germany
| | - Judith Klumperman
- Department of Cell Biology, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht 3584, Netherlands
| | - Markus Damme
- Institute of Biochemistry, Christian-Albrechts-University Kiel, Kiel 24118, Germany
| | - Tassula Proikas-Cezanne
- Department of Molecular Biology, Eberhard Karls University Tübingen, Tübingen 72076, Germany
| | - Christian A Hübner
- Institute of Human Genetics, University Hospital Jena, Friedrich-Schiller-University Jena, Jena 07747, Germany.
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Leal-Gutiérrez JD, Elzo MA, Johnson DD, Hamblen H, Mateescu RG. Genome wide association and gene enrichment analysis reveal membrane anchoring and structural proteins associated with meat quality in beef. BMC Genomics 2019; 20:151. [PMID: 30791866 PMCID: PMC6385435 DOI: 10.1186/s12864-019-5518-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 02/07/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Meat quality related phenotypes are difficult and expensive to measure and predict but are ideal candidates for genomic selection if genetic markers that account for a worthwhile proportion of the phenotypic variation can be identified. The objectives of this study were: 1) to perform genome wide association analyses for Warner-Bratzler Shear Force (WBSF), marbling, cooking loss, tenderness, juiciness, connective tissue and flavor; 2) to determine enriched pathways present in each genome wide association analysis; and 3) to identify potential candidate genes with multiple quantitative trait loci (QTL) associated with meat quality. RESULTS The WBSF, marbling and cooking loss traits were measured in longissimus dorsi muscle from 672 steers. Out of these, 495 animals were used to measure tenderness, juiciness, connective tissue and flavor by a sensory panel. All animals were genotyped for 221,077 markers and included in a genome wide association analysis. A total number of 68 genomic regions covering 52 genes were identified using the whole genome association approach; 48% of these genes encode transmembrane proteins or membrane associated molecules. Two enrichment analysis were performed: a tissue restricted gene enrichment applying a correlation analysis between raw associated single nucleotide polymorphisms (SNPs) by trait, and a functional classification analysis performed using the DAVID Bioinformatic Resources 6.8 server. The tissue restricted gene enrichment approach identified eleven pathways including "Endoplasmic reticulum membrane" that influenced multiple traits simultaneously. The DAVID functional classification analysis uncovered eleven clusters related to transmembrane or structural proteins. A gene network was constructed where the number of raw associated uncorrelated SNPs for each gene across all traits was used as a weight. A multiple SNP association analysis was performed for the top five most connected genes in the gene-trait network. The gene network identified the EVC2, ANXA10 and PKHD1 genes as potentially harboring multiple QTLs. Polymorphisms identified in structural proteins can modulate two different processes with direct effect on meat quality: in vivo myocyte cytoskeletal organization and postmortem proteolysis. CONCLUSION The main result from the present analysis is the uncovering of several candidate genes associated with meat quality that have structural function in the skeletal muscle.
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Affiliation(s)
| | - Mauricio A. Elzo
- Department of Animal Sciences, University of Florida, Gainesville, FL USA
| | - D. Dwain Johnson
- Department of Animal Sciences, University of Florida, Gainesville, FL USA
| | - Heather Hamblen
- Department of Animal Sciences, University of Florida, Gainesville, FL USA
| | - Raluca G. Mateescu
- Department of Animal Sciences, University of Florida, Gainesville, FL USA
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Trummer B, Haubenberger D, Blackstone C. Clinical Trial Designs and Measures in Hereditary Spastic Paraplegias. Front Neurol 2018; 9:1017. [PMID: 30627115 PMCID: PMC6309810 DOI: 10.3389/fneur.2018.01017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 11/12/2018] [Indexed: 01/19/2023] Open
Abstract
Hereditary spastic paraplegias (HSPs) are a large group of genetically-diverse neurologic disorders characterized clinically by a common feature of lower extremity spasticity and gait difficulties. Current therapies are predominantly symptomatic, and even then usually provide inadequate relief of symptoms. Going forward, HSP therapeutics development requires a systematic analysis of quantifiable measures and tools to assess treatment response. This review summarizes promising therapeutic targets, assessment measures, and previous clinical trials for the HSPs. Oxidative stress, signaling pathways, microtubule dynamics, and gene rescue/replacement have been proposed as potential treatment targets or modalities. Quantitative evaluation of pre-clinical rodent HSP models emphasize rotarod performance, foot base angle, grip strength, stride length, beam walking, critical speed, and body weight. Clinical measures of HSP in humans include 10-m gait velocity, the Spastic Paraplegia Rating Scale (SPRS), Ashworth Spasticity Scale, Fugl-Meyer Scale, timed up-and-go, and the Gillette Functional Assessment Questionnaire. We conducted a broad search for past clinical trials in HSPs and identified trials that investigated pharmacological agents including atorvastatin, gabapentin, L-threonine, botulinum toxin, dalfampridine, methylphenidate, and baclofen. We provide recommendations for future HSP treatment directions based on these prior research experiences as well as regulatory insight.
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Affiliation(s)
- Brian Trummer
- Neurogenetics Branch, Clinical Research Program, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
- Clinical Trials Unit, Clinical Research Program, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Dietrich Haubenberger
- Clinical Trials Unit, Clinical Research Program, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Craig Blackstone
- Neurogenetics Branch, Clinical Research Program, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
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Beetz C, Khundadze M, Goldberg LV, Hübner CA. Erbliche spastische Spinalparalysen: aktuelle Erkenntnisse und Entwicklungen. MED GENET-BERLIN 2018. [DOI: 10.1007/s11825-018-0196-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Zusammenfassung
Die erblichen spastischen Spinalparalysen („hereditary spastic paraplegias“, HSPs) sind Bewegungsstörungen, die aus der Degeneration der Axone oberer Motoneuronen resultieren. Sie sind klinisch und genetisch sehr heterogen. Der vorliegende Übersichtsartikel fasst aktuelle Strategien zur genetischen Diagnostik der HSPs zusammen, erörtert mögliche Mutationsmechanismen, diskutiert Erklärungen für die klinische Variabilität innerhalb ausgewählter Formen und verweist auf noch ungeklärte und zum Teil wenig beachtete Phänomene. Außerdem wird die Notwendigkeit eines tieferen Verständnisses der zellulären und molekularen Mechanismen für die Entwicklung neuer Therapien dargestellt.
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Affiliation(s)
- Christian Beetz
- Aff1 0000 0000 8517 6224 grid.275559.9 Institut für Klinische Chemie und Laboratoriumsdiagnostik Universitätsklinikum Jena Jena Deutschland
| | - Mukhran Khundadze
- Aff2 0000 0000 8517 6224 grid.275559.9 Institut für Humangenetik Universitätsklinikum Jena Am Klinikum 1 07747 Jena Deutschland
| | - Lisa V. Goldberg
- Aff1 0000 0000 8517 6224 grid.275559.9 Institut für Klinische Chemie und Laboratoriumsdiagnostik Universitätsklinikum Jena Jena Deutschland
| | - Christian A. Hübner
- Aff2 0000 0000 8517 6224 grid.275559.9 Institut für Humangenetik Universitätsklinikum Jena Am Klinikum 1 07747 Jena Deutschland
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Csordás G, Weaver D, Hajnóczky G. Endoplasmic Reticulum-Mitochondrial Contactology: Structure and Signaling Functions. Trends Cell Biol 2018; 28:523-540. [PMID: 29588129 DOI: 10.1016/j.tcb.2018.02.009] [Citation(s) in RCA: 335] [Impact Index Per Article: 55.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 02/23/2018] [Accepted: 02/23/2018] [Indexed: 02/08/2023]
Abstract
Interorganellar contacts are increasingly recognized as central to the control of cellular behavior. These contacts, which typically involve a small fraction of the endomembrane surface, are local communication hubs that resemble synapses. We propose the term contactology to denote the analysis of interorganellar contacts. Endoplasmic reticulum (ER) contacts with mitochondria were recognized several decades ago; major roles in ion and lipid transfer, signaling, and membrane dynamics have been established, while others continue to emerge. The functional diversity of ER-mitochondrial (ER-mito) contacts is mirrored in their structural heterogeneity, with subspecialization likely supported by multiple, different linker-forming protein structures. The nanoscale size of the contacts has made studying their structure, function, and dynamics difficult. This review focuses on the structure of the ER-mito contacts, methods for studying them, and the roles of contacts in Ca2+ and reactive oxygen species (ROS) signaling.
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Affiliation(s)
- György Csordás
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
| | - David Weaver
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
| | - György Hajnóczky
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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Abstract
The endoplasmic reticulum (ER) is a morphologically dynamic organelle containing different membrane subdomains with distinct cellular functions. Numerous observations have revealed that ER stress response induced by disturbed ER homeostasis is linked to various neurological/neurodegenerative disorders. In contrast, recent findings unveil that ER structural derangements are linked to the progression of several neurological diseases. The derangements involve two distinct, and likely opposing pathways. One is dysfunction of ER dynamics machinery, leading to disruption of ER network organization. Another one is facilitation of pre-existing machinery, leading to generation of markedly-ordered de novo membranous structure. Restoring the ER network can be the effective way toward the cure of ER-deranged neurological disorders.
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Affiliation(s)
- Tomoyuki Yamanaka
- Laboratory of Structural Neuropathology, Graduate School of Brain Science, Doshisha University, Kyoto, Japan
| | - Nobuyuki Nukina
- Laboratory of Structural Neuropathology, Graduate School of Brain Science, Doshisha University, Kyoto, Japan
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Kamada M, Kawarai T, Miyamoto R, Kawakita R, Tojima Y, Montecchiani C, D'Onofrio L, Caltagirone C, Orlacchio A, Kaji R. Spastic paraplegia type 31: A novel REEP1 splice site donor variant and expansion of the phenotype variability. Parkinsonism Relat Disord 2018; 46:79-83. [DOI: 10.1016/j.parkreldis.2017.10.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 09/28/2017] [Accepted: 10/18/2017] [Indexed: 11/26/2022]
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Seemann E, Sun M, Krueger S, Tröger J, Hou W, Haag N, Schüler S, Westermann M, Huebner CA, Romeike B, Kessels MM, Qualmann B. Deciphering caveolar functions by syndapin III KO-mediated impairment of caveolar invagination. eLife 2017; 6. [PMID: 29202928 PMCID: PMC5716666 DOI: 10.7554/elife.29854] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 11/14/2017] [Indexed: 12/11/2022] Open
Abstract
Several human diseases are associated with a lack of caveolae. Yet, the functions of caveolae and the molecular mechanisms critical for shaping them still are debated. We show that muscle cells of syndapin III KO mice show severe reductions of caveolae reminiscent of human caveolinopathies. Yet, different from other mouse models, the levels of the plasma membrane-associated caveolar coat proteins caveolin3 and cavin1 were both not reduced upon syndapin III KO. This allowed for dissecting bona fide caveolar functions from those supported by mere caveolin presence and also demonstrated that neither caveolin3 nor caveolin3 and cavin1 are sufficient to form caveolae. The membrane-shaping protein syndapin III is crucial for caveolar invagination and KO rendered the cells sensitive to membrane tensions. Consistent with this physiological role of caveolae in counterpoising membrane tensions, syndapin III KO skeletal muscles showed pathological parameters upon physical exercise that are also found in CAVEOLIN3 mutation-associated muscle diseases.
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Affiliation(s)
- Eric Seemann
- Institute for Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Minxuan Sun
- Institute for Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Sarah Krueger
- Institute for Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Jessica Tröger
- Institute for Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Wenya Hou
- Institute for Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Natja Haag
- Institute for Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Susann Schüler
- Institute for Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Martin Westermann
- Electron Microscopy Center, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Christian A Huebner
- Institute for Human Genetics, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Bernd Romeike
- Institute of Pathology, Division of Neuropathology, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Michael M Kessels
- Institute for Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Britta Qualmann
- Institute for Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
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Yalçın B, Zhao L, Stofanko M, O'Sullivan NC, Kang ZH, Roost A, Thomas MR, Zaessinger S, Blard O, Patto AL, Sohail A, Baena V, Terasaki M, O'Kane CJ. Modeling of axonal endoplasmic reticulum network by spastic paraplegia proteins. eLife 2017; 6. [PMID: 28742022 PMCID: PMC5576921 DOI: 10.7554/elife.23882] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 07/24/2017] [Indexed: 01/17/2023] Open
Abstract
Axons contain a smooth tubular endoplasmic reticulum (ER) network that is thought to be continuous with ER throughout the neuron; the mechanisms that form this axonal network are unknown. Mutations affecting reticulon or REEP proteins, with intramembrane hairpin domains that model ER membranes, cause an axon degenerative disease, hereditary spastic paraplegia (HSP). We show that Drosophila axons have a dynamic axonal ER network, which these proteins help to model. Loss of HSP hairpin proteins causes ER sheet expansion, partial loss of ER from distal motor axons, and occasional discontinuities in axonal ER. Ultrastructural analysis reveals an extensive ER network in axons, which shows larger and fewer tubules in larvae that lack reticulon and REEP proteins, consistent with loss of membrane curvature. Therefore HSP hairpin-containing proteins are required for shaping and continuity of axonal ER, thus suggesting roles for ER modeling in axon maintenance and function. DOI:http://dx.doi.org/10.7554/eLife.23882.001 The way we move – from simple motions like reaching out to grab something, to playing the piano or dancing – is coordinated in our brain. These processes involve many regions and steps, in which nerve cells transport signals along projections known as axons. Axons rely on sophisticated ‘engineering’ to work properly over long distances and are vulnerable to diseases that disrupt their engineering. For example, in genetic diseases called ‘hereditary spastic paraplegias’, damages to the ‘distal’ end of axons – the end furthest from the nerve cell body – cause paralysis of the lower body. Axons have several internal structures that make sure everything works properly. One of these structures is the endoplasmic reticulum, which is a network of tubular membranes that runs lengthwise along the axon. It is known that spastic paraplegias are sometimes caused by mutations affecting proteins that help to build and shape the endoplasmic reticulum, for example, the proteins of the reticulon and REEP families. However, until now it was not known how the ER forms its network in the axons and if this is influenced by these proteins. To see whether reticulons and REEPs affect the shape of the endoplasmic reticulum, Yalçιn et al. used healthy fruit fly larvae, and genetically modified ones that lacked the proteins. The results show that in healthy flies, the tubular network runs continuously along the axons. When either reticulon or REEP proteins were removed, the distal axons contained less endoplasmic reticulum. In mutant fly larvae that lacked both protein families, the endoplasmic reticulum was more interrupted and contained more gaps than in normal larvae. Using high-magnification electron microscopy confirmed these findings, and showed that the tubules of the endoplasmic reticulum in mutant axons were larger, but fewer. A next step will be to test whether these mutations also affect how the axons work and communicate over long distances. A better knowledge of the role of the endoplasmic reticulum in axons will help us to understand how damages to it could affect hereditary spastic paraplegias and other degenerative conditions. DOI:http://dx.doi.org/10.7554/eLife.23882.002
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Affiliation(s)
- Belgin Yalçın
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Lu Zhao
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Martin Stofanko
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Niamh C O'Sullivan
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Zi Han Kang
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Annika Roost
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Matthew R Thomas
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Sophie Zaessinger
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Olivier Blard
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Alex L Patto
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Anood Sohail
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Valentina Baena
- Department of Cell Biology, University of Connecticut Health Center, Farmington, United States
| | - Mark Terasaki
- Department of Cell Biology, University of Connecticut Health Center, Farmington, United States
| | - Cahir J O'Kane
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
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Renvoisé B, Malone B, Falgairolle M, Munasinghe J, Stadler J, Sibilla C, Park SH, Blackstone C. Reep1 null mice reveal a converging role for hereditary spastic paraplegia proteins in lipid droplet regulation. Hum Mol Genet 2017; 25:5111-5125. [PMID: 27638887 DOI: 10.1093/hmg/ddw315] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 09/12/2016] [Indexed: 12/21/2022] Open
Abstract
Hereditary spastic paraplegias (HSPs; SPG1-76 plus others) are length-dependent disorders affecting long corticospinal axons, and the most common autosomal dominant forms are caused by mutations in genes that encode the spastin (SPG4), atlastin-1 (SPG3A) and REEP1 (SPG31) proteins. These proteins bind one another and shape the tubular endoplasmic reticulum (ER) network throughout cells. They also are involved in lipid droplet formation, enlargement, or both in cells, though mechanisms remain unclear. Here we have identified evidence of partial lipoatrophy in Reep1 null mice in addition to prominent spastic paraparesis. Furthermore, Reep1-/- embryonic fibroblasts and neurons in the cerebral cortex both show lipid droplet abnormalities. The apparent partial lipodystrophy in Reep1 null mice, although less severe, is reminiscent of the lipoatrophy phenotype observed in the most common form of autosomal recessive lipodystrophy, Berardinelli-Seip congenital lipodystrophy. Berardinelli-Seip lipodystrophy is caused by autosomal recessive mutations in the BSCL2 gene that encodes an ER protein, seipin, that is also mutated in the autosomal dominant HSP SPG17 (Silver syndrome). Furthermore, REEP1 co-immunoprecipitates with seipin in cells. This strengthens the link between alterations in ER morphogenesis and lipid abnormalities, with important pathogenic implications for the most common forms of HSP.
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Affiliation(s)
| | | | | | - Jeeva Munasinghe
- Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
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Agrawal SA, Burgoyne T, Eblimit A, Bellingham J, Parfitt DA, Lane A, Nichols R, Asomugha C, Hayes MJ, Munro PM, Xu M, Wang K, Futter CE, Li Y, Chen R, Cheetham ME. REEP6 deficiency leads to retinal degeneration through disruption of ER homeostasis and protein trafficking. Hum Mol Genet 2017; 26:2667-2677. [PMID: 28475715 PMCID: PMC5808736 DOI: 10.1093/hmg/ddx149] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 04/12/2017] [Accepted: 04/14/2017] [Indexed: 01/09/2023] Open
Abstract
Retinitis pigmentosa (RP) is the most common form of inherited retinal dystrophy. We recently identified mutations in REEP6, which encodes the receptor expression enhancing protein 6, in several families with autosomal recessive RP. REEP6 is related to the REEP and Yop1p family of ER shaping proteins and potential receptor accessory proteins, but the role of REEP6 in the retina is unknown. Here we characterize the disease mechanisms associated with loss of REEP6 function using a Reep6 knockout mouse generated by CRISPR/Cas9 gene editing. In control mice REEP6 was localized to the inner segment and outer plexiform layer of rod photoreceptors. The Reep6-/- mice exhibited progressive photoreceptor degeneration from P20 onwards. Ultrastructural analyses at P20 by transmission electron microscopy and 3View serial block face scanning EM revealed an expansion of the distal ER in the Reep6-/- rods and an increase in their number of mitochondria. Electroretinograms revealed photoreceptor dysfunction preceded degeneration, suggesting potential defects in phototransduction. There was no effect on the traffic of rhodopsin, Rom1 or peripherin/rds; however, the retinal guanylate cyclases GC1 and GC2 were severely affected in the Reep6 knockout animals, with almost undetectable expression. These changes correlated with an increase in C/EBP homologous protein (CHOP) expression and the activation of caspase 12, suggesting that ER stress contributes to cell death. Collectively, these data suggest that REEP6 plays an essential role in maintaining cGMP homeostasis though facilitating the stability and/or trafficking of guanylate cyclases and maintaining ER and mitochondrial homeostasis.
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Affiliation(s)
- Smriti A. Agrawal
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Thomas Burgoyne
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Aiden Eblimit
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - James Bellingham
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - David A. Parfitt
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Amelia Lane
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | | | - Chinwe Asomugha
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Matthew J. Hayes
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Peter M. Munro
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Mingchu Xu
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Keqing Wang
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Clare E. Futter
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Yumei Li
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Rui Chen
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
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Lavie J, Serrat R, Bellance N, Courtand G, Dupuy JW, Tesson C, Coupry I, Brice A, Lacombe D, Durr A, Stevanin G, Darios F, Rossignol R, Goizet C, Bénard G. Mitochondrial morphology and cellular distribution are altered in SPG31 patients and are linked to DRP1 hyperphosphorylation. Hum Mol Genet 2017; 26:674-685. [PMID: 28007911 DOI: 10.1093/hmg/ddw425] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 12/12/2016] [Indexed: 01/07/2023] Open
Abstract
Hereditary spastic paraplegia, SPG31, is a rare neurological disorder caused by mutations in REEP1 gene encoding the microtubule-interacting protein, REEP1. The mechanism by which REEP1-dependent processes are linked with the disease is unclear. REEP1 regulates the morphology and trafficking of various organelles via interaction with the microtubules. In this study, we collected primary fibroblasts from SPG31 patients to investigate their mitochondrial morphology. We observed that the mitochondrial morphology in patient cells was highly tubular compared with control cells. We provide evidence that these morphological alterations are caused by the inhibition of mitochondrial fission protein, DRP1, due to the hyperphosphorylation of its serine 637 residue. This hyperphosphorylation is caused by impaired interactions between REEP1 and mitochondrial phosphatase PGAM5. Genetically or pharmacologically induced decrease of DRP1-S637 phosphorylation restores mitochondrial morphology in patient cells. Furthermore, ectopic expression of REEP1 carrying pathological mutations in primary neuronal culture targets REEP1 to the mitochondria. Mutated REEP1 proteins sequester mitochondria to the perinuclear region of the neurons and therefore, hamper mitochondrial transport along the axon. Considering the established role of mitochondrial distribution and morphology in neuronal health, our results support the involvement of a mitochondrial dysfunction in SPG31 pathology.
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Affiliation(s)
- Julie Lavie
- INSERM U1211, Laboratoire Maladies Rares: Génétique et Métabolisme. Hôpital Pellegrin, 33000 Bordeaux, France.,University of Bordeaux, 33077 Bordeaux, France
| | - Román Serrat
- University of Bordeaux, 33077 Bordeaux, France.,INSERM U1215, NeuroCentre Magendie, 33077 Bordeaux, France
| | - Nadège Bellance
- INSERM U1211, Laboratoire Maladies Rares: Génétique et Métabolisme. Hôpital Pellegrin, 33000 Bordeaux, France.,University of Bordeaux, 33077 Bordeaux, France
| | - Gilles Courtand
- University of Bordeaux, 33077 Bordeaux, France.,INCIA, Université de Bordeaux, CNRS UMR5287, Bordeaux, France
| | - Jean-William Dupuy
- University of Bordeaux, 33077 Bordeaux, France.,Plateforme Protéome, Centre de Génomique Fonctionnelle, F-33000 Bordeaux, France
| | - Christelle Tesson
- INSERM U1127, CNRS UMR 7225, UPMC Université Paris 06 UMR S1127, Sorbonne Université Institut du Cerveau et de la Moelle épinière, ICM F-75013, Paris, France.,Ecole Pratique des Hautes Etudes, PSL Research University, 75014 Paris, France
| | - Isabelle Coupry
- INSERM U1211, Laboratoire Maladies Rares: Génétique et Métabolisme. Hôpital Pellegrin, 33000 Bordeaux, France.,University of Bordeaux, 33077 Bordeaux, France
| | - Alexis Brice
- INSERM U1127, CNRS UMR 7225, UPMC Université Paris 06 UMR S1127, Sorbonne Université Institut du Cerveau et de la Moelle épinière, ICM F-75013, Paris, France
| | - Didier Lacombe
- INSERM U1211, Laboratoire Maladies Rares: Génétique et Métabolisme. Hôpital Pellegrin, 33000 Bordeaux, France.,University of Bordeaux, 33077 Bordeaux, France
| | - Alexandra Durr
- INSERM U1127, CNRS UMR 7225, UPMC Université Paris 06 UMR S1127, Sorbonne Université Institut du Cerveau et de la Moelle épinière, ICM F-75013, Paris, France
| | - Giovanni Stevanin
- INSERM U1127, CNRS UMR 7225, UPMC Université Paris 06 UMR S1127, Sorbonne Université Institut du Cerveau et de la Moelle épinière, ICM F-75013, Paris, France.,Ecole Pratique des Hautes Etudes, PSL Research University, 75014 Paris, France
| | - Fréderic Darios
- INSERM U1127, CNRS UMR 7225, UPMC Université Paris 06 UMR S1127, Sorbonne Université Institut du Cerveau et de la Moelle épinière, ICM F-75013, Paris, France
| | - Rodrigue Rossignol
- INSERM U1211, Laboratoire Maladies Rares: Génétique et Métabolisme. Hôpital Pellegrin, 33000 Bordeaux, France.,University of Bordeaux, 33077 Bordeaux, France
| | - Cyril Goizet
- INSERM U1211, Laboratoire Maladies Rares: Génétique et Métabolisme. Hôpital Pellegrin, 33000 Bordeaux, France.,University of Bordeaux, 33077 Bordeaux, France
| | - Giovanni Bénard
- INSERM U1211, Laboratoire Maladies Rares: Génétique et Métabolisme. Hôpital Pellegrin, 33000 Bordeaux, France.,University of Bordeaux, 33077 Bordeaux, France
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Allison R, Edgar JR, Pearson G, Rizo T, Newton T, Günther S, Berner F, Hague J, Connell JW, Winkler J, Lippincott-Schwartz J, Beetz C, Winner B, Reid E. Defects in ER-endosome contacts impact lysosome function in hereditary spastic paraplegia. J Cell Biol 2017; 216:1337-1355. [PMID: 28389476 PMCID: PMC5412567 DOI: 10.1083/jcb.201609033] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 01/20/2017] [Accepted: 02/21/2017] [Indexed: 01/29/2023] Open
Abstract
Hereditary spastic paraplegia (HSP) is a genetically heterogeneous disease caused by mutations in many genes, including those encoding spastin, strumpellin, or REEP1. Allison et al. show that similar lysosomal phenotypes are associated with mutations in different classes of HSP proteins and suggest that defective ER–endosome contacts and endosome tubule fission may be a common cause of axon degeneration in the disease. Contacts between endosomes and the endoplasmic reticulum (ER) promote endosomal tubule fission, but the mechanisms involved and consequences of tubule fission failure are incompletely understood. We found that interaction between the microtubule-severing enzyme spastin and the ESCRT protein IST1 at ER–endosome contacts drives endosomal tubule fission. Failure of fission caused defective sorting of mannose 6-phosphate receptor, with consequently disrupted lysosomal enzyme trafficking and abnormal lysosomal morphology, including in mouse primary neurons and human stem cell–derived neurons. Consistent with a role for ER-mediated endosomal tubule fission in lysosome function, similar lysosomal abnormalities were seen in cellular models lacking the WASH complex component strumpellin or the ER morphogen REEP1. Mutations in spastin, strumpellin, or REEP1 cause hereditary spastic paraplegia (HSP), a disease characterized by axonal degeneration. Our results implicate failure of the ER–endosome contact process in axonopathy and suggest that coupling of ER-mediated endosomal tubule fission to lysosome function links different classes of HSP proteins, previously considered functionally distinct, into a unifying pathway for axonal degeneration.
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Affiliation(s)
- Rachel Allison
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England, UK.,Department of Medical Genetics, University of Cambridge, Cambridge CB2 0XY, England, UK
| | - James R Edgar
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England, UK.,Department of Clinical Biochemistry, University of Cambridge, Cambridge CB2 0XY, England, UK
| | - Guy Pearson
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England, UK.,Department of Medical Genetics, University of Cambridge, Cambridge CB2 0XY, England, UK
| | - Tania Rizo
- Interdisciplinary Center for Clinical Research (IZKF) Junior Research Group III and Federal Ministry of Education and Research (BMBF) Research Group Neuroscience, Friedrich-Alexander-University Erlangen-Nuernberg, 91054 Erlangen, Germany
| | - Timothy Newton
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England, UK.,Department of Medical Genetics, University of Cambridge, Cambridge CB2 0XY, England, UK
| | - Sven Günther
- Department of Clinical Chemistry and Laboratory Diagnostics, Jena University Hospital, 07743 Jena, Germany
| | - Fiamma Berner
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England, UK
| | - Jennifer Hague
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England, UK.,Department of Medical Genetics, University of Cambridge, Cambridge CB2 0XY, England, UK
| | - James W Connell
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England, UK.,Department of Medical Genetics, University of Cambridge, Cambridge CB2 0XY, England, UK
| | - Jürgen Winkler
- Department of Molecular Neurology, Friedrich-Alexander-University Erlangen-Nuernberg, 91054 Erlangen, Germany
| | | | - Christian Beetz
- Department of Clinical Chemistry and Laboratory Diagnostics, Jena University Hospital, 07743 Jena, Germany
| | - Beate Winner
- Interdisciplinary Center for Clinical Research (IZKF) Junior Research Group III and Federal Ministry of Education and Research (BMBF) Research Group Neuroscience, Friedrich-Alexander-University Erlangen-Nuernberg, 91054 Erlangen, Germany.,Institute of Human Genetics, Friedrich-Alexander-University Erlangen-Nuernberg, 91054 Erlangen, Germany
| | - Evan Reid
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England, UK .,Department of Medical Genetics, University of Cambridge, Cambridge CB2 0XY, England, UK
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49
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De Mario A, Quintana-Cabrera R, Martinvalet D, Giacomello M. (Neuro)degenerated Mitochondria-ER contacts. Biochem Biophys Res Commun 2017; 483:1096-1109. [DOI: 10.1016/j.bbrc.2016.07.056] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 07/10/2016] [Indexed: 01/24/2023]
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50
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Richard S, Lavie J, Banneau G, Voirand N, Lavandier K, Debouverie M. Hereditary spastic paraplegia due to a novel mutation of the REEP1 gene: Case report and literature review. Medicine (Baltimore) 2017; 96:e5911. [PMID: 28099355 PMCID: PMC5279100 DOI: 10.1097/md.0000000000005911] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
RATIONALE Hereditary spastic paraplegia (HSP) is a heterogeneous group of diseases little known in clinical practice due to its low prevalence, slow progression, and difficult diagnosis. This results in an underestimation of HSP leading to belated diagnosis and management. In depth diagnosis is based on clinical presentation and identification of genomic mutations. We describe the clinical presentation and pathogeny of HSP through a report of a case due to a novel mutation of the REEP1 gene (SPG31). PATIENT CONCERNS A 64-year-old woman presented gait disturbances due to spasticity of the lower limbs progressing since her third decade. Previous investigations failed to find any cause. INTERVENTIONS DNA analysis was performed to search for HSP causing mutations. DIAGNOSES A novel heterozygote mutation (c.595 + 1G>A) of the REEP1 gene, within the splice site of intron 6, was discovered. This nucleotide change causes exon 6 skipping leading to frame shift and a truncated transcript identified by complementary DNA sequencing of reverse transcription polymerase chain reaction products. OUTCOMES REEP1 is a known protein predominantly located in the upper motor neurons. Mutation of REEP1 primary affects the longest axons explaining predominance of pyramidal syndrome on lower limbs. LESSONS Slow progressive pyramidal syndrome of the lower limbs should elicit a diagnosis of HSP. We describe a novel mutation of the REEP1 gene causing HSP. Pathogeny is based on resulting abnormal REEP1 protein which is involved in the development of longest axons constituting the corticospinal tracts.
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Affiliation(s)
- Sébastien Richard
- Department of Neurology, University Hospital of Nancy, Nancy
- Department of Neurology, Hospital of Bar-le-Duc, Bar-le-Duc
- Centre d’Investigation Clinique Plurithématique CIC-P 1433, Inserm U1116, University Hospital of Nancy, Vandoeuvre-lès-Nancy
| | - Julie Lavie
- Laboratory of Rare Diseases: Genetic and Metabolism (MRGM), University Hospital Pellegrin, Bordeaux
| | - Guillaume Banneau
- Department of Genetics, Pitié-Salpêtrière Hospital, Public Hospital Network of Paris, Paris, France
| | | | | | - Marc Debouverie
- Department of Neurology, University Hospital of Nancy, Nancy
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