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Wiseman JP, Scarrott JM, Alves-Cruzeiro J, Saffari A, Böger C, Karyka E, Dawes E, Davies AK, Marchi PM, Graves E, Fernandes F, Yang ZL, Coldicott I, Hirst J, Webster CP, Highley JR, Hackett N, Angyal A, Silva TD, Higginbottom A, Shaw PJ, Ferraiuolo L, Ebrahimi-Fakhari D, Azzouz M. Pre-clinical development of AP4B1 gene replacement therapy for hereditary spastic paraplegia type 47. EMBO Mol Med 2024:10.1038/s44321-024-00148-5. [PMID: 39358605 DOI: 10.1038/s44321-024-00148-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 09/17/2024] [Accepted: 09/19/2024] [Indexed: 10/04/2024] Open
Abstract
Spastic paraplegia 47 (SPG47) is a neurological disorder caused by mutations in the adaptor protein complex 4 β1 subunit (AP4B1) gene leading to AP-4 complex deficiency. SPG47 is characterised by progressive spastic paraplegia, global developmental delay, intellectual disability and epilepsy. Gene therapy aimed at restoring functional AP4B1 protein levels is a rational therapeutic strategy to ameliorate the disease phenotype. Here we report that a single delivery of adeno-associated virus serotype 9 expressing hAP4B1 (AAV9/hAP4B1) into the cisterna magna leads to widespread gene transfer and restoration of various hallmarks of disease, including AP-4 cargo (ATG9A) mislocalisation, calbindin-positive spheroids in the deep cerebellar nuclei, anatomical brain defects and motor dysfunction, in an SPG47 mouse model. Furthermore, AAV9/hAP4B1-based gene therapy demonstrated a restoration of plasma neurofilament light (NfL) levels of treated mice. Encouraged by these preclinical proof-of-concept data, we conducted IND-enabling studies, including immunogenicity and GLP non-human primate (NHP) toxicology studies. Importantly, NHP safety and biodistribution study revealed no significant adverse events associated with the therapeutic intervention. These findings provide evidence of both therapeutic efficacy and safety, establishing a robust basis for the pursuit of an IND application for clinical trials targeting SPG47 patients.
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Affiliation(s)
- Jessica P Wiseman
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Western Bank, Sheffield, UK
| | - Joseph M Scarrott
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, University of Sheffield, Sheffield, UK
- Gene Therapy Innovation & Manufacturing Centre (GTIMC), Division of Neuroscience, University of Sheffield, Sheffield, UK
| | - João Alves-Cruzeiro
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, University of Sheffield, Sheffield, UK
| | - Afshin Saffari
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Movement Disorders Program, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Division of Child Neurology and Inherited Metabolic Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Cedric Böger
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Movement Disorders Program, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Evangelia Karyka
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, University of Sheffield, Sheffield, UK
- Gene Therapy Innovation & Manufacturing Centre (GTIMC), Division of Neuroscience, University of Sheffield, Sheffield, UK
| | - Emily Dawes
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, University of Sheffield, Sheffield, UK
| | - Alexandra K Davies
- School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
- Cambridge Institute for Medical Research, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK
| | - Paolo M Marchi
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, University of Sheffield, Sheffield, UK
| | - Emily Graves
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, University of Sheffield, Sheffield, UK
| | - Fiona Fernandes
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, University of Sheffield, Sheffield, UK
| | - Zih-Liang Yang
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Western Bank, Sheffield, UK
| | - Ian Coldicott
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Western Bank, Sheffield, UK
| | - Jennifer Hirst
- Cambridge Institute for Medical Research, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK
| | - Christopher P Webster
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Western Bank, Sheffield, UK
| | - J Robin Highley
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Western Bank, Sheffield, UK
| | | | - Adrienn Angyal
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | - Thushan de Silva
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | - Adrian Higginbottom
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Western Bank, Sheffield, UK
| | - Pamela J Shaw
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Western Bank, Sheffield, UK
- Sheffield NIHR Biomedical Research Centre, Sheffield Teaching Hospitals NHS Foundation Trust, Glossop Road, Sheffield, UK
| | - Laura Ferraiuolo
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, University of Sheffield, Sheffield, UK
| | - Darius Ebrahimi-Fakhari
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Movement Disorders Program, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Mimoun Azzouz
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, University of Sheffield, Sheffield, UK.
- Neuroscience Institute, University of Sheffield, Western Bank, Sheffield, UK.
- Gene Therapy Innovation & Manufacturing Centre (GTIMC), Division of Neuroscience, University of Sheffield, Sheffield, UK.
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2
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Janzing AM, Eklund E, De Koning TJ, Eggink H. Clinical Characteristics Suggestive of a Genetic Cause in Cerebral Palsy: A Systematic Review. Pediatr Neurol 2024; 153:144-151. [PMID: 38382247 DOI: 10.1016/j.pediatrneurol.2024.01.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 01/11/2024] [Accepted: 01/27/2024] [Indexed: 02/23/2024]
Abstract
BACKGROUND Cerebral palsy (CP) is a clinical diagnosis and was long categorized as an acquired disorder, but more and more genetic etiologies are being identified. This review aims to identify the clinical characteristics that are associated with genetic CP to aid clinicians in selecting candidates for genetic testing. METHODS The PubMed database was systematically searched to identify genes associated with CP. The clinical characteristics accompanying these genetic forms of CP were compared with published data of large CP populations resulting in the identification of potential indicators of genetic CP. RESULLTS Of 1930 articles retrieved, 134 were included. In these, 55 CP genes (described in two or more cases, n = 272) and 79 candidate genes (described in only one case) were reported. The most frequently CP-associated genes were PLP1 (21 cases), ARG1 (17 cases), and CTNNB1 (13 cases). Dyskinesia and the absence of spasticity were identified as strong potential indicators of genetic CP. Presence of intellectual disability, no preterm birth, and no unilateral distribution of symptoms were classified as moderate genetic indicators. CONCLUSIONS Genetic causes of CP are increasingly identified. The clinical characteristics associated with genetic CP can aid clinicians regarding to which individual with CP to offer genetic testing. The identified potential genetic indicators need to be validated in large CP cohorts but can provide the first step toward a diagnostic algorithm for genetic CP.
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Affiliation(s)
- Anna M Janzing
- Department of Neurology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; Expertise Center Movement Disorders Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Erik Eklund
- Faculty of Medicine, Department of Clinical Sciences, Pediatrics, Lund University, Lund, Sweden
| | - Tom J De Koning
- Expertise Center Movement Disorders Groningen, University Medical Center Groningen, Groningen, The Netherlands; Faculty of Medicine, Department of Clinical Sciences, Pediatrics, Lund University, Lund, Sweden; Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Hendriekje Eggink
- Department of Neurology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands; Expertise Center Movement Disorders Groningen, University Medical Center Groningen, Groningen, The Netherlands.
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3
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Orsini A, Santangelo A, Carmignani A, Camporeale A, Massart F, Tyutyusheva N, Peroni DG, Foiadelli T, Ferretti A, Toschi B, Romano S, Bonuccelli A. An Ultra-Rare Mixed Phenotype with Combined AP-4 and ERF Mutations: The First Report in a Pediatric Patient and a Literature Review. Genes (Basel) 2024; 15:436. [PMID: 38674371 PMCID: PMC11049481 DOI: 10.3390/genes15040436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 03/26/2024] [Accepted: 03/27/2024] [Indexed: 04/28/2024] Open
Abstract
The adaptor protein 4 (AP-4) constitutes a conserved hetero-tetrameric complex within the family of adaptor protein (AP) complex, crucial for the signal-mediated trafficking of integral membrane proteins. Mutations affecting all subunits of the AP-4 complex have been linked to autosomal-recessive cerebral palsy and a complex hereditary spastic paraparesis (HSP) phenotype. Our report details the case of a 14-year-old boy born to consanguineous parents, presenting psychomotor delay, severe intellectual disability, microcephaly, and trigonocephaly. Despite a history of febrile seizures, subsequent years were devoid of seizures, with normal EEG. Exome sequencing revealed pathogenic variants in both the AP4B1 and ERF genes. Significantly, the patient exhibited features associated with AP4B1 mutations, including distinctive traits such as cranial malformations. The ERF gene variant, linked to craniosynostosis, likely contributes to the observed trigonocephaly. This case represents the initial documentation of a concurrent mutation in the AP4B1 and ERF genes, underscoring the critical role of exome analysis in unraveling complex phenotypes. Understanding these complex genotypes offers valuable insights into broader syndromic conditions, facilitating comprehensive patient management.
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Affiliation(s)
- Alessandro Orsini
- Pediatric Neurology, Pediatric Department, AOUP Santa Chiara Hospital, 56100 Pisa, Italy; (A.O.); (A.B.)
| | - Andrea Santangelo
- Pediatric Neurology, Pediatric Department, AOUP Santa Chiara Hospital, 56100 Pisa, Italy; (A.O.); (A.B.)
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, 16126 Genoa, Italy
| | - Alessandra Carmignani
- Pediatric Department, AOUP Santa Chiara Hospital, 56100 Pisa, Italy; (A.C.); (A.C.); (D.G.P.)
| | - Anna Camporeale
- Pediatric Department, AOUP Santa Chiara Hospital, 56100 Pisa, Italy; (A.C.); (A.C.); (D.G.P.)
| | - Francesco Massart
- Pediatric Endocrinology, Pediatric Department, AOUP Santa Chiara Hospital, 56100 Pisa, Italy; (F.M.); (N.T.)
| | - Nina Tyutyusheva
- Pediatric Endocrinology, Pediatric Department, AOUP Santa Chiara Hospital, 56100 Pisa, Italy; (F.M.); (N.T.)
| | - Diego Giampietro Peroni
- Pediatric Department, AOUP Santa Chiara Hospital, 56100 Pisa, Italy; (A.C.); (A.C.); (D.G.P.)
| | - Thomas Foiadelli
- Clinica Pediatrica, Fondazione IRCCS Policlinico San Matteo, 27100 Pavia, Italy;
| | - Alessandro Ferretti
- Pediatrics Unit, Neuroscience, Mental Health and Sense Organs (NESMOS) Department, Faculty of Medicine and Psychology, Sapienza University of Rome, 00185 Rome, Italy;
| | - Benedetta Toschi
- Division of Medical Genetics, Department of Medical and Oncological Area, University-Hospital, 56126 Pisa, Italy; (B.T.); (S.R.)
| | - Silvia Romano
- Division of Medical Genetics, Department of Medical and Oncological Area, University-Hospital, 56126 Pisa, Italy; (B.T.); (S.R.)
| | - Alice Bonuccelli
- Pediatric Neurology, Pediatric Department, AOUP Santa Chiara Hospital, 56100 Pisa, Italy; (A.O.); (A.B.)
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4
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Caracci MO, Pizarro H, Alarcón-Godoy C, Fuentealba LM, Farfán P, De Pace R, Santibañez N, Cavieres VA, Pástor TP, Bonifacino JS, Mardones GA, Marzolo MP. The Reelin receptor ApoER2 is a cargo for the adaptor protein complex AP-4: Implications for Hereditary Spastic Paraplegia. Prog Neurobiol 2024; 234:102575. [PMID: 38281682 PMCID: PMC10979513 DOI: 10.1016/j.pneurobio.2024.102575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 01/11/2024] [Accepted: 01/23/2024] [Indexed: 01/30/2024]
Abstract
Adaptor protein complex 4 (AP-4) is a heterotetrameric complex that promotes export of selected cargo proteins from the trans-Golgi network. Mutations in each of the AP-4 subunits cause a complicated form of Hereditary Spastic Paraplegia (HSP). Herein, we report that ApoER2, a receptor in the Reelin signaling pathway, is a cargo of the AP-4 complex. We identify the motif ISSF/Y within the ApoER2 cytosolic domain as necessary for interaction with the canonical signal-binding pocket of the µ4 (AP4M1) subunit of AP-4. AP4E1- knock-out (KO) HeLa cells and hippocampal neurons from Ap4e1-KO mice display increased co-localization of ApoER2 with Golgi markers. Furthermore, hippocampal neurons from Ap4e1-KO mice and AP4M1-KO human iPSC-derived cortical i3Neurons exhibit reduced ApoER2 protein expression. Analyses of biosynthetic transport of ApoER2 reveal differential post-Golgi trafficking of the receptor, with lower axonal distribution in KO compared to wild-type neurons, indicating a role of AP-4 and the ISSF/Y motif in the axonal localization of ApoER2. Finally, analyses of Reelin signaling in mouse hippocampal and human cortical KO neurons show that AP4 deficiency causes no changes in Reelin-dependent activation of the AKT pathway and only mild changes in Reelin-induced dendritic arborization, but reduces Reelin-induced ERK phosphorylation, CREB activation, and Golgi deployment. This work thus establishes ApoER2 as a novel cargo of the AP-4 complex, suggesting that defects in the trafficking of this receptor and in the Reelin signaling pathway could contribute to the pathogenesis of HSP caused by mutations in AP-4 subunits.
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Affiliation(s)
- Mario O Caracci
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago, Chile
| | - Héctor Pizarro
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago, Chile
| | - Carlos Alarcón-Godoy
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago, Chile
| | - Luz M Fuentealba
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago, Chile
| | - Pamela Farfán
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago, Chile
| | - Raffaella De Pace
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Natacha Santibañez
- Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile
| | - Viviana A Cavieres
- Departamento de Ciencias Biológicas y Químicas, Fac. Med y Ciencia, USS, Santiago, Chile
| | - Tammy P Pástor
- Escuela de Medicina, Facultad de Medicina y Ciencia, Universidad San Sebastián, Valdivia, Chile
| | - Juan S Bonifacino
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Gonzalo A Mardones
- Escuela de Medicina, Facultad de Medicina y Ciencia, Universidad San Sebastián, Valdivia, Chile
| | - María-Paz Marzolo
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, P. Universidad Católica de Chile, Santiago, Chile.
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5
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Saffari A, Brechmann B, Böger C, Saber WA, Jumo H, Whye D, Wood D, Wahlster L, Alecu JE, Ziegler M, Scheffold M, Winden K, Hubbs J, Buttermore ED, Barrett L, Borner GHH, Davies AK, Ebrahimi-Fakhari D, Sahin M. High-content screening identifies a small molecule that restores AP-4-dependent protein trafficking in neuronal models of AP-4-associated hereditary spastic paraplegia. Nat Commun 2024; 15:584. [PMID: 38233389 PMCID: PMC10794252 DOI: 10.1038/s41467-023-44264-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 12/06/2023] [Indexed: 01/19/2024] Open
Abstract
Unbiased phenotypic screens in patient-relevant disease models offer the potential to detect therapeutic targets for rare diseases. In this study, we developed a high-throughput screening assay to identify molecules that correct aberrant protein trafficking in adapter protein complex 4 (AP-4) deficiency, a rare but prototypical form of childhood-onset hereditary spastic paraplegia characterized by mislocalization of the autophagy protein ATG9A. Using high-content microscopy and an automated image analysis pipeline, we screened a diversity library of 28,864 small molecules and identified a lead compound, BCH-HSP-C01, that restored ATG9A pathology in multiple disease models, including patient-derived fibroblasts and induced pluripotent stem cell-derived neurons. We used multiparametric orthogonal strategies and integrated transcriptomic and proteomic approaches to delineate potential mechanisms of action of BCH-HSP-C01. Our results define molecular regulators of intracellular ATG9A trafficking and characterize a lead compound for the treatment of AP-4 deficiency, providing important proof-of-concept data for future studies.
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Affiliation(s)
- Afshin Saffari
- Department of Neurology & F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
- Division of Child Neurology and Inherited Metabolic Diseases, Heidelberg University Hospital, Heidelberg, Germany
| | - Barbara Brechmann
- Department of Neurology & F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Cedric Böger
- Department of Neurology & F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Wardiya Afshar Saber
- Department of Neurology & F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Hellen Jumo
- Department of Neurology & F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Dosh Whye
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Delaney Wood
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Lara Wahlster
- Department of Hematology & Oncology, Boston Children's Hospital & Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Julian E Alecu
- Department of Neurology & F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Marvin Ziegler
- Department of Neurology & F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Marlene Scheffold
- Department of Neurology & F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Kellen Winden
- Department of Neurology & F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Jed Hubbs
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Elizabeth D Buttermore
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Lee Barrett
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Georg H H Borner
- Department of Proteomics and Signal Transduction, Max-Planck-Institute of Biochemistry, Martinsried, 82152, Germany
| | - Alexandra K Davies
- Department of Proteomics and Signal Transduction, Max-Planck-Institute of Biochemistry, Martinsried, 82152, Germany
- School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, M13 9PT, UK
| | - Darius Ebrahimi-Fakhari
- Department of Neurology & F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA.
- Movement Disorders Program, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA.
| | - Mustafa Sahin
- Department of Neurology & F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
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6
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Caracci MO, Pizarro H, Alarcón-Godoy C, Fuentealba LM, Farfán P, Pace RD, Santibañez N, Cavieres VA, Pástor TP, Bonifacino JS, Mardones GA, Marzolo MP. The Reelin Receptor ApoER2 is a Cargo for the Adaptor Protein Complex AP-4: Implications for Hereditary Spastic Paraplegia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.21.572896. [PMID: 38187774 PMCID: PMC10769347 DOI: 10.1101/2023.12.21.572896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Adaptor protein complex 4 (AP-4) is a heterotetrameric complex that promotes protein export from the trans -Golgi network. Mutations in each of the AP-4 subunits cause a complicated form of Hereditary Spastic Paraplegia (HSP). Herein, we report that ApoER2, a receptor in the Reelin signaling pathway, is a cargo of the AP-4 complex. We identify the motif ISSF/Y within the ApoER2 cytosolic domain as necessary for interaction with the canonical signal-binding pocket of the µ4 (AP4M1) subunit of AP-4. AP4E1 -knock-out (KO) HeLa cells and hippocampal neurons from Ap4e1 -KO mice display increased Golgi localization of ApoER2. Furthermore, hippocampal neurons from Ap4e1 -KO mice and AP4M1 -KO human iPSC-derived cortical i3Neurons exhibit reduced ApoER2 protein expression. Analyses of biosynthetic transport of ApoER2 reveal differential post-Golgi trafficking of the receptor, with lower axonal distribution in KO compared to wild-type neurons, indicating a role of AP-4 and the ISSF/Y motif in the axonal localization of ApoER2. Finally, analyses of Reelin signaling in mouse hippocampal and human cortical KO neurons show that AP4 deficiency causes no changes in Reelin-dependent activation of the AKT pathway and only mild changes in Reelin-induced dendritic arborization, but reduces Reelin-induced ERK phosphorylation, CREB activation, and Golgi deployment. Altogether, this work establishes ApoER2 as a novel cargo of the AP-4 complex, suggesting that defects in the trafficking of this receptor and in the Reelin signaling pathway could contribute to the pathogenesis of HSP caused by mutations in AP-4 subunits.
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7
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Li Y, Zhang C, Peng G. Ap4s1 truncation leads to axonal defects in a zebrafish model of spastic paraplegia 52. Int J Dev Neurosci 2023; 83:753-764. [PMID: 37767851 DOI: 10.1002/jdn.10303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 08/11/2023] [Accepted: 09/08/2023] [Indexed: 09/29/2023] Open
Abstract
Biallelic mutations in AP4S1, the σ4 subunit of the adaptor protein complex 4 (AP-4), lead to autosomal recessive spastic paraplegia 52 (SPG52). It is a subtype of AP-4-associated hereditary spastic paraplegia (AP-4-HSP), a complex childhood-onset neurogenetic disease characterized by progressive spastic paraplegia of the lower limbs. This disease has so far lacked effective treatment, in part due to a lack of suitable animal models. Here, we used CRISPR/Cas9 technology to generate a truncation mutation in the ap4s1 gene in zebrafish. The ap4s1 truncation led to motor impairment, delayed neurodevelopment, and distal axonal degeneration. This animal model is useful for further research into AP-4 and AP-4-HSP.
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Affiliation(s)
- Yiduo Li
- State Key Laboratory of Medical Neurobiology, Ministry of Education Frontiers Center for Brain Science, and Institutes of Brain Science, Fudan University, Shanghai, China
| | - Cuizhen Zhang
- State Key Laboratory of Medical Neurobiology, Ministry of Education Frontiers Center for Brain Science, and Institutes of Brain Science, Fudan University, Shanghai, China
| | - Gang Peng
- State Key Laboratory of Medical Neurobiology, Ministry of Education Frontiers Center for Brain Science, and Institutes of Brain Science, Fudan University, Shanghai, China
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8
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Alecu JE, Saffari A, Ziegler M, Jordan C, Tam A, Kim S, Leung E, Szczaluba K, Mierzewska H, King SD, Santorelli FM, Yoon G, Trombetta B, Kivisäkk P, Zhang B, Sahin M, Ebrahimi-Fakhari D. Plasma Neurofilament Light Chain Is Elevated in Adaptor Protein Complex 4-Related Hereditary Spastic Paraplegia. Mov Disord 2023; 38:1742-1750. [PMID: 37482941 PMCID: PMC10529494 DOI: 10.1002/mds.29524] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 05/15/2023] [Accepted: 06/09/2023] [Indexed: 07/25/2023] Open
Abstract
BACKGROUND Adaptor protein complex 4-associated hereditary spastic paraplegia (AP-4-HSP) is caused by pathogenic biallelic variants in AP4B1, AP4M1, AP4E1, and AP4S1. OBJECTIVE The aim was to explore blood markers of neuroaxonal damage in AP-4-HSP. METHODS Plasma neurofilament light chain (pNfL) and glial fibrillary acidic protein (GFAP) levels were measured in samples from patients and age- and sex-matched controls (NfL: n = 46 vs. n = 46; GFAP: n = 14 vs. n = 21) using single-molecule array assays. Patients' phenotypes were systematically assessed using the AP-4-HSP natural history study questionnaires, the Spastic Paraplegia Rating Scale, and the SPATAX disability score. RESULTS pNfL levels increased in AP-4-HSP patients, allowing differentiation from controls (Mann-Whitney U test: P = 3.0e-10; area under the curve = 0.87 with a 95% confidence interval of 0.80-0.94). Phenotypic cluster analyses revealed a subgroup of individuals with severe generalized-onset seizures and developmental stagnation, who showed differentially higher pNfL levels (Mann-Whitney U test between two identified clusters: P = 2.5e-6). Plasma GFAP levels were unchanged in patients with AP-4-HSP. CONCLUSIONS pNfL is a potential disease marker in AP-4-HSP and can help differentiate between phenotypic subgroups. © 2023 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Julian E. Alecu
- Department of Neurology and F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
- Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
| | - Afshin Saffari
- Department of Neurology and F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Marvin Ziegler
- Department of Neurology and F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Catherine Jordan
- Department of Neurology and F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Amy Tam
- Department of Neurology and F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Soyoung Kim
- Sozialpaediatrisches Zentrum Frankfurt Mitte, Frankfurt am Main, Germany
| | - Edward Leung
- Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, Manitoba, Canada
| | | | - Hanna Mierzewska
- Department of Neurology, Institute of Mother and Child, Warsaw, Poland
| | - Staci D. King
- Department of Neurology, Texas Children’s Hospital, Houston, Texas, USA
| | | | - Grace Yoon
- Divisions of Clinical and Metabolic Genetics and Neurology, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Bianca Trombetta
- Alzheimer’s Clinical and Translational Research Unit, Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Pia Kivisäkk
- Alzheimer’s Clinical and Translational Research Unit, Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Bo Zhang
- Department of Neurology and F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
- ICCTR Biostatistics and Research Design Center, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Mustafa Sahin
- Department of Neurology and F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children’s Hospital, Boston, Massachusetts, USA
- Intellectual and Developmental Disabilities Research Center, Boston Children’s Hospital, Boston, Massachusetts, USA
| | - Darius Ebrahimi-Fakhari
- Department of Neurology and F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children’s Hospital, Boston, Massachusetts, USA
- Intellectual and Developmental Disabilities Research Center, Boston Children’s Hospital, Boston, Massachusetts, USA
- Movement Disorders Program, Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
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9
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Martinello C, Panza E, Orlacchio A. Hereditary spastic paraplegias proteome: common pathways and pathogenetic mechanisms. Expert Rev Proteomics 2023; 20:171-188. [PMID: 37788157 DOI: 10.1080/14789450.2023.2260952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 08/31/2023] [Indexed: 10/05/2023]
Abstract
INTRODUCTION Hereditary spastic paraplegias (HSPs) are a group of inherited neurodegenerative disorders characterized by progressive spasticity and weakness of the lower limbs. These conditions are caused by lesions in the neuronal pyramidal tract and exhibit clinical and genetic variability. Ongoing research focuses on understanding the underlying mechanisms of HSP onset, which ultimately lead to neuronal degeneration. Key molecular mechanisms involved include axonal transport, cytoskeleton dynamics, myelination abnormalities, membrane trafficking, organelle morphogenesis, ER homeostasis, mitochondrial dysfunction, and autophagy deregulation. AREAS COVERED This review aims to provide an overview of the shared pathogenetic mechanisms in various forms of HSPs. By examining disease-causing gene products and their associated functional pathways, this understanding could lead to the discovery of new therapeutic targets and the development of treatments to modify the progression of the disease. EXPERT OPINION Investigating gene functionality is crucial for identifying shared pathogenetic pathways underlying different HSP subtypes. Categorizing protein function and identifying pathways aids in finding biomarkers, predicting early onset, and guiding treatment for a better quality of life. Targeting shared mechanisms enables efficient and cost-effective therapies. Prospects involve identifying new disease-causing genes, refining molecular processes, and implementing findings in diagnosis, key for advancing HSP understanding and developing effective treatments.
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Affiliation(s)
- Chiara Martinello
- Dipartimento di Scienze Mediche e Chirurgiche, Università di Bologna, Bologna, Italy
| | - Emanuele Panza
- Dipartimento di Scienze Mediche e Chirurgiche, Università di Bologna, Bologna, Italy
- Unità di Genetica Medica, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy
| | - Antonio Orlacchio
- Laboratorio di Neurogenetica, Centro Europeo di Ricerca sul Cervello (CERC), Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Fondazione Santa Lucia, Rome, Italy
- Dipartimento di Medicina e Chirurgia, Università di Perugia, Perugia, Italy
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10
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Saffari A, Brechmann B, Boeger C, Saber WA, Jumo H, Whye D, Wood D, Wahlster L, Alecu J, Ziegler M, Scheffold M, Winden K, Hubbs J, Buttermore E, Barrett L, Borner G, Davies A, Sahin M, Ebrahimi-Fakhari D. High-Content Small Molecule Screen Identifies a Novel Compound That Restores AP-4-Dependent Protein Trafficking in Neuronal Models of AP-4-Associated Hereditary Spastic Paraplegia. RESEARCH SQUARE 2023:rs.3.rs-3036166. [PMID: 37398196 PMCID: PMC10312991 DOI: 10.21203/rs.3.rs-3036166/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Unbiased phenotypic screens in patient-relevant disease models offer the potential to detect novel therapeutic targets for rare diseases. In this study, we developed a high-throughput screening assay to identify molecules that correct aberrant protein trafficking in adaptor protein complex 4 (AP-4) deficiency, a rare but prototypical form of childhood-onset hereditary spastic paraplegia, characterized by mislocalization of the autophagy protein ATG9A. Using high-content microscopy and an automated image analysis pipeline, we screened a diversity library of 28,864 small molecules and identified a lead compound, C-01, that restored ATG9A pathology in multiple disease models, including patient-derived fibroblasts and induced pluripotent stem cell-derived neurons. We used multiparametric orthogonal strategies and integrated transcriptomic and proteomic approaches to delineate putative molecular targets of C-01 and potential mechanisms of action. Our results define molecular regulators of intracellular ATG9A trafficking and characterize a lead compound for the treatment of AP-4 deficiency, providing important proof-of-concept data for future Investigational New Drug (IND)-enabling studies.
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Affiliation(s)
| | | | | | | | | | - Dosh Whye
- Boston Children's Hospital, Harvard Medical School
| | - Delaney Wood
- Boston Children's Hospital, Harvard Medical School
| | | | - Julian Alecu
- Boston Children's Hospital, Harvard Medical School
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11
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Scarrott JM, Alves-Cruzeiro J, Marchi PM, Webster CP, Yang ZL, Karyka E, Marroccella R, Coldicott I, Thomas H, Azzouz M. Ap4b1-knockout mouse model of hereditary spastic paraplegia type 47 displays motor dysfunction, aberrant brain morphology and ATG9A mislocalization. Brain Commun 2023; 5:fcac335. [PMID: 36632189 PMCID: PMC9825813 DOI: 10.1093/braincomms/fcac335] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 10/19/2022] [Accepted: 01/03/2023] [Indexed: 01/09/2023] Open
Abstract
Mutations in any one of the four subunits (ɛ4, β4, μ4 and σ4) comprising the adaptor protein Complex 4 results in a complex form of hereditary spastic paraplegia, often termed adaptor protein Complex 4 deficiency syndrome. Deficits in adaptor protein Complex 4 complex function have been shown to disrupt intracellular trafficking, resulting in a broad phenotypic spectrum encompassing severe intellectual disability and progressive spastic paraplegia of the lower limbs in patients. Here we report the presence of neuropathological hallmarks of adaptor protein Complex 4 deficiency syndrome in a clustered regularly interspaced short palindromic repeats-mediated Ap4b1-knockout mouse model. Mice lacking the β4 subunit, and therefore lacking functional adaptor protein Complex 4, have a thin corpus callosum, enlarged lateral ventricles, motor co-ordination deficits, hyperactivity, a hindlimb clasping phenotype associated with neurodegeneration, and an abnormal gait. Analysis of autophagy-related protein 9A (a known cargo of the adaptor protein Complex 4 in these mice shows both upregulation of autophagy-related protein 9A protein levels across multiple tissues, as well as a striking mislocalization of autophagy-related protein 9A from a generalized cytoplasmic distribution to a marked accumulation in the trans-Golgi network within cells. This mislocalization is present in mature animals but is also in E15.5 embryonic cortical neurons. Histological examination of brain regions also shows an accumulation of calbindin-positive spheroid aggregates in the deep cerebellar nuclei of adaptor protein Complex 4-deficient mice, at the site of Purkinje cell axonal projections. Taken together, these findings show a definitive link between loss-of-function mutations in murine Ap4b1 and the development of symptoms consistent with adaptor protein Complex 4 deficiency disease in humans. Furthermore, this study provides strong evidence for the use of this model for further research into the aetiology of adaptor protein Complex 4 deficiency in humans, as well as its use for the development and testing of new therapeutic modalities.
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Affiliation(s)
- Joseph M Scarrott
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield S10 2HQ, UK
| | - João Alves-Cruzeiro
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield S10 2HQ, UK
- URI Neuroscience Institute, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Paolo M Marchi
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield S10 2HQ, UK
- URI Neuroscience Institute, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Christopher P Webster
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield S10 2HQ, UK
- URI Neuroscience Institute, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Zih-Liang Yang
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield S10 2HQ, UK
- URI Neuroscience Institute, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Evangelia Karyka
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield S10 2HQ, UK
- URI Neuroscience Institute, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Raffaele Marroccella
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield S10 2HQ, UK
| | - Ian Coldicott
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield S10 2HQ, UK
- URI Neuroscience Institute, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Hannah Thomas
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield S10 2HQ, UK
- URI Neuroscience Institute, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Mimoun Azzouz
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield S10 2HQ, UK
- URI Neuroscience Institute, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
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12
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Pembridge OG, Wallace NS, Clements TP, Jackson LP. AP-4 loss in CRISPR-edited zebrafish affects early embryo development. Adv Biol Regul 2023; 87:100945. [PMID: 36642642 PMCID: PMC9992121 DOI: 10.1016/j.jbior.2022.100945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 12/12/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022]
Abstract
Mutations in the heterotetrametric adaptor protein 4 (AP-4; ε/β4/μ4/σ4 subunits) membrane trafficking coat complex lead to complex neurological disorders characterized by spastic paraplegia, microcephaly, and intellectual disabilities. Understanding molecular mechanisms underlying these disorders continues to emerge with recent identification of an essential autophagy protein, ATG9A, as an AP-4 cargo. Significant progress has been made uncovering AP-4 function in cell culture and patient-derived cell lines, and ATG9A trafficking by AP-4 is considered a potential target for gene therapy approaches. In contrast, understanding how AP-4 trafficking affects development and function at the organismal level has long been hindered by loss of conserved AP-4 genes in key model systems (S. cerevisiae, C. elegans, D. melanogaster). However, zebrafish (Danio rerio) have retained AP-4 and can serve as an important model system for studying both the nervous system and overall development. We undertook gene editing in zebrafish using a CRISPR-ExoCas9 knockout system to determine how loss of single AP-4, or its accessory protein tepsin, genes affect embryo development 24 h post-fertilization (hpf). Single gene-edited embryos display abnormal head morphology and neural necrosis. We further conducted the first exploration of how AP-4 single gene knockouts in zebrafish embryos affect expression levels and patterns of two autophagy genes, atg9a and map1lc3b. This work suggests zebrafish may be further adapted and developed as a tool to uncover AP-4 function in membrane trafficking and autophagy in the context of a model organism.
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Affiliation(s)
- Olivia G Pembridge
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Natalie S Wallace
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN, USA
| | - Thomas P Clements
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Lauren P Jackson
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN, USA; Department of Biochemistry, Vanderbilt University, Nashville, TN, USA.
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13
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Ebrahimi-Fakhari D, Saffari A, Pearl PL. Childhood-onset hereditary spastic paraplegia and its treatable mimics. Mol Genet Metab 2022; 137:436-444. [PMID: 34183250 PMCID: PMC8843241 DOI: 10.1016/j.ymgme.2021.06.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 06/18/2021] [Accepted: 06/19/2021] [Indexed: 12/24/2022]
Abstract
Early-onset forms of hereditary spastic paraplegia and inborn errors of metabolism that present with spastic diplegia are among the most common "mimics" of cerebral palsy. Early detection of these heterogenous genetic disorders can inform genetic counseling, anticipatory guidance, and improve outcomes, particularly where specific treatments exist. The diagnosis relies on clinical pattern recognition, biochemical testing, neuroimaging, and increasingly next-generation sequencing-based molecular testing. In this short review, we summarize the clinical and molecular understanding of: 1) childhood-onset and complex forms of hereditary spastic paraplegia (SPG5, SPG7, SPG11, SPG15, SPG35, SPG47, SPG48, SPG50, SPG51, SPG52) and, 2) the most common inborn errors of metabolism that present with phenotypes that resemble hereditary spastic paraplegia.
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Affiliation(s)
- Darius Ebrahimi-Fakhari
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA, USA.
| | - Afshin Saffari
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Division of Child Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, Heidelberg University Hospital, Heidelberg, Germany
| | - Phillip L Pearl
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
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14
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Salayev K, Rocca C, Kaiyrzhanov R, Guliyeva U, Guliyeva S, Mursalova A, Rahman F, Anwar N, Zafar F, Jan F, Rana N, Maqbool S, Efthymiou S, Houlden H. AP4B1-associated hereditary spastic paraplegia: Expansion of clinico-genetic phenotype and geographic range. Eur J Med Genet 2022; 65:104620. [PMID: 36122674 DOI: 10.1016/j.ejmg.2022.104620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 05/22/2022] [Accepted: 09/12/2022] [Indexed: 11/20/2022]
Abstract
BACKGROUND Hereditary spastic paraplegias (HSP) are a group of neurodegenerative diseases that present with weakness and stiffness in the lower limb muscles and lead to progressive neurological decline. Bi-allelic loss-of-function variants in genes that encode subunits of the adaptor protein complex 4 (AP-4) lead to complex HSP. This study aimed to identify causative genetic variants in consanguineous families with HSP from Azerbaijan and Pakistan. METHODS We performed a thorough clinical and neuroradiological characterization followed by exome sequencing in 7 patients from 3 unrelated families. Segregation analysis was subsequently performed by Sanger sequencing. RESULTS We describe 7 patients (4 males, 2-31 years of age) with developmental delay and spasticity. Similar to the previously reported cases with AP4B1-associated HSP, cases in the present report besides spasticity in the lower limbs had additional features including microcephaly, facial dysmorphism, infantile hypotonia, and epilepsy. The imaging findings included thin corpus callosum, white matter loss, and ventriculomegaly. CONCLUSION In this study, we report 7 novel cases of HSP caused by bi-allelic variants in AP4B1 in Azerbaijani and Pakistani families. Our observations will help clinicians observe and compare common and unique clinical features of AP4B1-associated HSP patients, further improving our current understanding of HSP.
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Affiliation(s)
- Kamran Salayev
- Azerbaijan Medical University, Department of Neurology, Baku, AZ, 1010, Azerbaijan
| | - Clarissa Rocca
- University College London, Institute of Neurology, Department of Neuromuscular Disorders, Queen Square, WC1N 3BG, London, UK
| | - Rauan Kaiyrzhanov
- University College London, Institute of Neurology, Department of Neuromuscular Disorders, Queen Square, WC1N 3BG, London, UK
| | - Ulviyya Guliyeva
- MediClub Hospital, 45, Uzeyir Hajibeyli Str., Baku, AZ, 1010, Azerbaijan
| | - Sughra Guliyeva
- MediClub Hospital, 45, Uzeyir Hajibeyli Str., Baku, AZ, 1010, Azerbaijan
| | - Aytan Mursalova
- Baku City Gerontologic Centre, Azadliq Ave., Baku, Azerbaijan
| | - Fatima Rahman
- Development and Behavioral Pediatrics Department, Institute of Child Health and the Children Hospital, Lahore, 54000, Pakistan
| | - Najwa Anwar
- Development and Behavioral Pediatrics Department, Institute of Child Health and the Children Hospital, Lahore, 54000, Pakistan
| | - Faisal Zafar
- Department of Paediatric Neurology, Children's Hospital and Institute of Child Health, Multan, Pakistan
| | - Farida Jan
- Department of Paediatrics and Child Health, Aga Khan University Hospital, Karachi, Pakistan
| | - Nuzhat Rana
- Department of Paediatric Neurology, Children's Hospital and Institute of Child Health, Multan, Pakistan
| | - Shazia Maqbool
- Development and Behavioral Pediatrics Department, Institute of Child Health and the Children Hospital, Lahore, 54000, Pakistan
| | - Stephanie Efthymiou
- University College London, Institute of Neurology, Department of Neuromuscular Disorders, Queen Square, WC1N 3BG, London, UK
| | - Henry Houlden
- University College London, Institute of Neurology, Department of Neuromuscular Disorders, Queen Square, WC1N 3BG, London, UK.
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15
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Mulkerrin G, França MC, Lope J, Tan EL, Bede P. Neuroimaging in hereditary spastic paraplegias: from qualitative cues to precision biomarkers. Expert Rev Mol Diagn 2022; 22:745-760. [PMID: 36042576 DOI: 10.1080/14737159.2022.2118048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
INTRODUCTION : Hereditary spastic paraplegias (HSP) include a clinically and genetically heterogeneous group of conditions. Novel imaging modalities have been increasingly applied to HSP cohorts which helps to quantitatively evaluate the integrity of specific anatomical structures and develop monitoring markers for both clinical care and future clinical trials. AREAS COVERED : Advances in HSP imaging are systematically reviewed with a focus on cohort sizes, imaging modalities, study design, clinical correlates, methodological approaches, and key findings. EXPERT OPINION : A wide range of imaging techniques have been recently applied to HSP cohorts. Common shortcomings of existing studies include the evaluation of genetically unconfirmed or admixed cohorts, limited sample sizes, unimodal imaging approaches, lack of postmortem validation, and a limited clinical battery, often exclusively focusing on motor aspects of the condition. A number of innovative methodological approaches have also be identified, such as robust longitudinal study designs, the implementation of multimodal imaging protocols, complementary cognitive assessments, and the comparison of HSP cohorts to MND cohorts. Collaborative multicentre initiatives may overcome sample limitations, and comprehensive clinical profiling with motor, extrapyramidal, cerebellar, and neuropsychological assessments would permit systematic clinico-radiological correlations. Academic achievements in HSP imaging have the potential to be developed into viable clinical applications to expedite the diagnosis and monitor disease progression.
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Affiliation(s)
| | - Marcondes C França
- Department of Neurology, The State University of Campinas, São Paulo, Brazil
| | - Jasmin Lope
- Computational Neuroimaging Group, Trinity College Dublin, Ireland
| | - Ee Ling Tan
- Computational Neuroimaging Group, Trinity College Dublin, Ireland
| | - Peter Bede
- Department of Neurology, St James's Hospital, Dublin, Ireland.,Computational Neuroimaging Group, Trinity College Dublin, Ireland
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16
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Majumder P, Edmison D, Rodger C, Patel S, Reid E, Gowrishankar S. AP-4 regulates neuronal lysosome composition, function, and transport via regulating export of critical lysosome receptor proteins at the trans-Golgi network. Mol Biol Cell 2022; 33:ar102. [PMID: 35976706 PMCID: PMC9635302 DOI: 10.1091/mbc.e21-09-0473] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The adaptor protein complex-4 or AP-4 is known to mediate autophagosome maturation through regulating sorting of transmembrane cargo such as ATG9A at the Golgi. There is a need to understand AP-4 function in neurons, as mutations in any of its four subunits cause a complex form of hereditary spastic paraplegia (HSP) with intellectual disability. While AP-4 has been implicated in regulating trafficking and distribution of cargo such as ATG9A and APP, little is known about its effect on neuronal lysosomal protein traffic, lysosome biogenesis and function. In this study, we demonstrate that in human iPSC-derived neurons AP-4 regulates lysosome composition, function and transport via regulating export of critical lysosomal receptors, including Sortilin 1, from the trans-Golgi network to endo-lysosomes. Additionally, loss of AP-4 causes endo-lysosomes to stall and build up in axonal swellings potentially through reduced recruitment of retrograde transport machinery to the organelle. These findings of axonal lysosome build-up are highly reminiscent of those observed in Alzheimer's disease as well as in neurons modelling the most common form of HSP, caused by spastin mutations. Our findings implicate AP-4 as a critical regulator of neuronal lysosome biogenesis and altered lysosome function and axonal endo-lysosome transport as an underlying defect in AP-4 deficient HSP. Additionally, our results also demonstrate the utility of the human i3Neuronal model system in investigating neuronal phenotypes observed in AP-4 deficient mice and/or the human AP-4 deficiency syndrome. [Media: see text] [Media: see text].
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Affiliation(s)
- Piyali Majumder
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Daisy Edmison
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Catherine Rodger
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England, UK
| | - Sruchi Patel
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Evan Reid
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, England, UK
| | - Swetha Gowrishankar
- Department of Anatomy and Cell Biology, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
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17
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Davies AK, Alecu JE, Ziegler M, Vasilopoulou CG, Merciai F, Jumo H, Afshar-Saber W, Sahin M, Ebrahimi-Fakhari D, Borner GHH. AP-4-mediated axonal transport controls endocannabinoid production in neurons. Nat Commun 2022; 13:1058. [PMID: 35217685 PMCID: PMC8881493 DOI: 10.1038/s41467-022-28609-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 01/08/2022] [Indexed: 01/20/2023] Open
Abstract
The adaptor protein complex AP-4 mediates anterograde axonal transport and is essential for axon health. AP-4-deficient patients suffer from a severe neurodevelopmental and neurodegenerative disorder. Here we identify DAGLB (diacylglycerol lipase-beta), a key enzyme for generation of the endocannabinoid 2-AG (2-arachidonoylglycerol), as a cargo of AP-4 vesicles. During normal development, DAGLB is targeted to the axon, where 2-AG signalling drives axonal growth. We show that DAGLB accumulates at the trans-Golgi network of AP-4-deficient cells, that axonal DAGLB levels are reduced in neurons from a patient with AP-4 deficiency, and that 2-AG levels are reduced in the brains of AP-4 knockout mice. Importantly, we demonstrate that neurite growth defects of AP-4-deficient neurons are rescued by inhibition of MGLL (monoacylglycerol lipase), the enzyme responsible for 2-AG hydrolysis. Our study supports a new model for AP-4 deficiency syndrome in which axon growth defects arise through spatial dysregulation of endocannabinoid signalling. Davies et al. identify a putative mechanism underlying the childhood neurological disorder AP-4 deficiency syndrome. In the absence of AP-4, an enzyme that makes 2-AG is not transported to the axon, leading to axonal growth defects, which can be rescued by inhibition of 2-AG breakdown.
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Affiliation(s)
- Alexandra K Davies
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, 82152, Germany.
| | - Julian E Alecu
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Marvin Ziegler
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA.,Department of Functional Neuroanatomy, Institute of Anatomy and Cell Biology, Heidelberg University, INF 307, Heidelberg, 69120, Germany
| | - Catherine G Vasilopoulou
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, 82152, Germany
| | - Fabrizio Merciai
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, 82152, Germany.,Department of Pharmacy and PhD Program in Drug Discovery and Development, University of Salerno, 84084, Fisciano, SA, Italy
| | - Hellen Jumo
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Wardiya Afshar-Saber
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Mustafa Sahin
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA.,Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Darius Ebrahimi-Fakhari
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Georg H H Borner
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, 82152, Germany.
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18
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Marrone L, Marchi PM, Webster CP, Marroccella R, Coldicott I, Reynolds S, Alves-Cruzeiro J, Yang ZL, Higginbottom A, Khundadze M, Shaw PJ, Hübner CA, Livesey MR, Azzouz M. OUP accepted manuscript. Hum Mol Genet 2022; 31:2693-2710. [PMID: 35313342 PMCID: PMC9402239 DOI: 10.1093/hmg/ddac063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 02/26/2022] [Accepted: 03/10/2022] [Indexed: 11/26/2022] Open
Abstract
Hereditary spastic paraplegia type 15 (HSP15) is a neurodegenerative condition caused by the inability to produce SPG15 protein, which leads to lysosomal swelling. However, the link between lysosomal aberrations and neuronal death is poorly explored. To uncover the functional consequences of lysosomal aberrations in disease pathogenesis, we analyze human dermal fibroblasts from HSP15 patients as well as primary cortical neurons derived from an SPG15 knockout (KO) mouse model. We find that SPG15 protein loss induces defective anterograde transport, impaired neurite outgrowth, axonal swelling and reduced autophagic flux in association with the onset of lysosomal abnormalities. Additionally, we observe lipid accumulation within the lysosomal compartment, suggesting that distortions in cellular lipid homeostasis are intertwined with lysosomal alterations. We further demonstrate that SPG15 KO neurons exhibit synaptic dysfunction, accompanied by augmented vulnerability to glutamate-induced excitotoxicity. Overall, our study establishes an intimate link between lysosomal aberrations, lipid metabolism and electrophysiological impairments, suggesting that lysosomal defects are at the core of multiple neurodegenerative disease processes in HSP15.
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Affiliation(s)
- Lara Marrone
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, UK
- Department of Neuroscience, Janssen Pharmaceutica, Beerse, Belgium
| | - Paolo M Marchi
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, UK
| | - Christopher P Webster
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, UK
| | - Raffaele Marroccella
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, UK
| | - Ian Coldicott
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, UK
| | - Steven Reynolds
- Academic Unit of Radiology, Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Royal Hallamshire Hospital, Sheffield, UK
| | - João Alves-Cruzeiro
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, UK
| | - Zih-Liang Yang
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, UK
| | - Adrian Higginbottom
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, UK
| | - Mukhran Khundadze
- Institute of Human Genetics, Jena University Hospital, Friedrich-Schiller-University Jena, Jena, Germany
| | - Pamela J Shaw
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, UK
| | - Christian A Hübner
- Institute of Human Genetics, Jena University Hospital, Friedrich-Schiller-University Jena, Jena, Germany
| | - Matthew R Livesey
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, UK
| | - Mimoun Azzouz
- To whom correspondence should be addressed. Tel: +44 1142222238; Fax: +44 (0)114 2222290; Email
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19
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Gómez-González C, Pizarro-Sánchez C, Rodríguez-Antolín C, Pascual-Pascual I, Garcia-Romero M, Rodriguez-Jiménez C, de Sancho-Martín R, Del Pozo-Mate Á, Solís-López M, Prior-de Castro C, Torres RJ. Hereditary spastic paraplegia associated with a novel homozygous intronic noncanonical splice site variant in the AP4B1 gene. Ann Hum Genet 2021; 86:109-118. [PMID: 34927723 DOI: 10.1111/ahg.12455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 11/15/2021] [Accepted: 12/02/2021] [Indexed: 11/27/2022]
Abstract
Pathogenic variants in the AP4B1 gene lead to a rare form of hereditary spastic paraplegia (HSP) known as SPG47. We report on a patient with a clinical suspicion of complicated HSP of the lower limbs with intellectual disability, as well as a novel homozygous noncanonical splice site variant in the AP4B1 gene, in which the effect on splicing was validated by RNA analysis. We sequenced 152 genes associated with HSP using Next-Generation Sequencing (NGS). We isolated total RNA from peripheral blood and generated cDNA using reverse transcription-polymerase chain reaction (RT-PCR). A region of AP4B1 mRNA was amplified by PCR and the fragments obtained were purified from the agarose gel and sequenced. We found a homozygous variant of uncertain significance in the AP4B1 gene NM_006594.4: c.1511-6C>G in the proband. Two different AP4B1 mRNA fragments were obtained in the patient and his carrier parents. The shorter fragment was the predominant fragment in the patient and revealed a deletion with skipping of the AP4B1 exon 10. The patient's longer fragment corresponded to an insertion of the last five nucleotides of AP4B1 intron 9. We confirmed that this variant affects the normal splicing of RNA, sustaining the molecular diagnosis of SPG47 in the patient.
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Affiliation(s)
- Clara Gómez-González
- Department of Molecular Genetics, INGEMM, La Paz University Hospital, Madrid, Spain
| | | | - Carlos Rodríguez-Antolín
- Cancer Epigenetics Laboratory, INGEMM, La Paz University Hospital, Madrid, Spain.,Biomarkers and Experimental Therapeutics in Cancer, IdiPAZ, Madrid, Spain
| | | | - Mar Garcia-Romero
- Department of Paediatric Neurology, La Paz University Hospital, Madrid, Spain
| | | | | | | | - Mario Solís-López
- Department of Bioinformatics, INGEMM, La Paz University Hospital, Madrid, Spain
| | | | - Rosa J Torres
- Biochemistry Laboratory, La Paz University Hospital Health Research Institute (FIBHULP), IdiPAZ, Madrid, Spain.,Centre for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Spain
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20
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Shin J, Nile A, Oh JW. Role of adaptin protein complexes in intracellular trafficking and their impact on diseases. Bioengineered 2021; 12:8259-8278. [PMID: 34565296 PMCID: PMC8806629 DOI: 10.1080/21655979.2021.1982846] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 09/15/2021] [Accepted: 09/15/2021] [Indexed: 02/07/2023] Open
Abstract
Adaptin proteins (APs) play a crucial role in intracellular cell trafficking. The 'classical' role of APs is carried out by AP1‒3, which bind to clathrin, cargo, and accessory proteins. Accordingly, AP1-3 are crucial for both vesicle formation and sorting. All APs consist of four subunits that are indispensable for their functions. In fact, based on studies using cells, model organism knockdown/knock-out, and human variants, each subunit plays crucial roles and contributes to the specificity of each AP. These studies also revealed that the sorting and intracellular trafficking function of AP can exert varying effects on pathology by controlling features such as cell development, signal transduction related to the apoptosis and proliferation pathways in cancer cells, organelle integrity, receptor presentation, and viral infection. Although the roles and functions of AP1‒3 are relatively well studied, the functions of the less abundant and more recently identified APs, AP4 and AP5, are still to be investigated. Further studies on these APs may enable a better understanding and targeting of specific diseases.APs known or suggested locations and functions.
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Affiliation(s)
- Juhyun Shin
- Department of Stem Cell and Regenerative Biotechnology and Animal Resources Research Center, Konkuk University, Seoul, Republic of Korea
| | - Arti Nile
- Department of Stem Cell and Regenerative Biotechnology and Animal Resources Research Center, Konkuk University, Seoul, Republic of Korea
| | - Jae-Wook Oh
- Department of Stem Cell and Regenerative Biotechnology and Animal Resources Research Center, Konkuk University, Seoul, Republic of Korea
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21
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Ebrahimi-Fakhari D, Alecu JE, Ziegler M, Geisel G, Jordan C, D'Amore A, Yeh RC, Akula SK, Saffari A, Prabhu SP, Sahin M, Yang E. Systematic Analysis of Brain MRI Findings in Adaptor Protein Complex 4-Associated Hereditary Spastic Paraplegia. Neurology 2021; 97:e1942-e1954. [PMID: 34544818 DOI: 10.1212/wnl.0000000000012836] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 08/23/2021] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND AND OBJECTIVES AP-4-associated hereditary spastic paraplegia (AP-4-HSP: SPG47, SPG50, SPG51, SPG52) is an emerging cause of childhood-onset hereditary spastic paraplegia and mimic of cerebral palsy. This study aims to define the spectrum of brain MRI findings in AP-4-HSP and to investigate radioclinical correlations. METHODS We performed a systematic qualitative and quantitative analysis of 107 brain MRI studies from 76 individuals with genetically confirmed AP-4-HSP and correlation with clinical findings including surrogates of disease severity. RESULTS We define AP-4-HSP as a disorder of gray and white matter and demonstrate that abnormal myelination is common and that metrics of reduced white matter volume correlate with severity of motor symptoms. We identify a common diagnostic imaging signature consisting of (1) a thin splenium of the corpus callosum, (2) an absent or thin anterior commissure, (3) characteristic signal abnormalities of the forceps minor ("ears of the grizzly sign"), and (4) periventricular white matter abnormalities. The presence of 2 or more of these findings has a sensitivity of ∼99% for detecting AP-4-HSP; the combination of all 4 is found in ∼45% of cases. Compared to other HSPs with a thin corpus callosum, the absent anterior commissure appears to be specific to AP-4-HSP. Our analysis identified a subset of patients with polymicrogyria, underscoring the role of AP-4 in early brain development. These patients displayed a higher prevalence of seizures and status epilepticus, many at a young age. DISCUSSION Our findings define the MRI spectrum of AP-4-HSP, providing opportunities for early diagnosis, identification of individuals at risk for complications, and a window into the role of the AP-4 complex in brain development and neurodegeneration.
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Affiliation(s)
- Darius Ebrahimi-Fakhari
- From the Department of Neurology (D.E.-F., J.E.A., M.Z., G.G., C.J., A.D., A.S., M.S.), and Division of Neuroradiology, Department of Radiology (S.P.P., E.Y.), The Manton Center for Orphan Disease Research (D.E.-F., R.C.Y., S.K.A.), Rosamund Stone Zander Translational Neuroscience Center (M.S.), and Division of Genetics and Genomics (D.E.-F., R.C.Y., S.K.A.), Boston Children's Hospital, Harvard Medical School, MA.
| | - Julian E Alecu
- From the Department of Neurology (D.E.-F., J.E.A., M.Z., G.G., C.J., A.D., A.S., M.S.), and Division of Neuroradiology, Department of Radiology (S.P.P., E.Y.), The Manton Center for Orphan Disease Research (D.E.-F., R.C.Y., S.K.A.), Rosamund Stone Zander Translational Neuroscience Center (M.S.), and Division of Genetics and Genomics (D.E.-F., R.C.Y., S.K.A.), Boston Children's Hospital, Harvard Medical School, MA
| | - Marvin Ziegler
- From the Department of Neurology (D.E.-F., J.E.A., M.Z., G.G., C.J., A.D., A.S., M.S.), and Division of Neuroradiology, Department of Radiology (S.P.P., E.Y.), The Manton Center for Orphan Disease Research (D.E.-F., R.C.Y., S.K.A.), Rosamund Stone Zander Translational Neuroscience Center (M.S.), and Division of Genetics and Genomics (D.E.-F., R.C.Y., S.K.A.), Boston Children's Hospital, Harvard Medical School, MA
| | - Gregory Geisel
- From the Department of Neurology (D.E.-F., J.E.A., M.Z., G.G., C.J., A.D., A.S., M.S.), and Division of Neuroradiology, Department of Radiology (S.P.P., E.Y.), The Manton Center for Orphan Disease Research (D.E.-F., R.C.Y., S.K.A.), Rosamund Stone Zander Translational Neuroscience Center (M.S.), and Division of Genetics and Genomics (D.E.-F., R.C.Y., S.K.A.), Boston Children's Hospital, Harvard Medical School, MA
| | - Catherine Jordan
- From the Department of Neurology (D.E.-F., J.E.A., M.Z., G.G., C.J., A.D., A.S., M.S.), and Division of Neuroradiology, Department of Radiology (S.P.P., E.Y.), The Manton Center for Orphan Disease Research (D.E.-F., R.C.Y., S.K.A.), Rosamund Stone Zander Translational Neuroscience Center (M.S.), and Division of Genetics and Genomics (D.E.-F., R.C.Y., S.K.A.), Boston Children's Hospital, Harvard Medical School, MA
| | - Angelica D'Amore
- From the Department of Neurology (D.E.-F., J.E.A., M.Z., G.G., C.J., A.D., A.S., M.S.), and Division of Neuroradiology, Department of Radiology (S.P.P., E.Y.), The Manton Center for Orphan Disease Research (D.E.-F., R.C.Y., S.K.A.), Rosamund Stone Zander Translational Neuroscience Center (M.S.), and Division of Genetics and Genomics (D.E.-F., R.C.Y., S.K.A.), Boston Children's Hospital, Harvard Medical School, MA
| | - Rebecca C Yeh
- From the Department of Neurology (D.E.-F., J.E.A., M.Z., G.G., C.J., A.D., A.S., M.S.), and Division of Neuroradiology, Department of Radiology (S.P.P., E.Y.), The Manton Center for Orphan Disease Research (D.E.-F., R.C.Y., S.K.A.), Rosamund Stone Zander Translational Neuroscience Center (M.S.), and Division of Genetics and Genomics (D.E.-F., R.C.Y., S.K.A.), Boston Children's Hospital, Harvard Medical School, MA
| | - Shyam K Akula
- From the Department of Neurology (D.E.-F., J.E.A., M.Z., G.G., C.J., A.D., A.S., M.S.), and Division of Neuroradiology, Department of Radiology (S.P.P., E.Y.), The Manton Center for Orphan Disease Research (D.E.-F., R.C.Y., S.K.A.), Rosamund Stone Zander Translational Neuroscience Center (M.S.), and Division of Genetics and Genomics (D.E.-F., R.C.Y., S.K.A.), Boston Children's Hospital, Harvard Medical School, MA
| | - Afshin Saffari
- From the Department of Neurology (D.E.-F., J.E.A., M.Z., G.G., C.J., A.D., A.S., M.S.), and Division of Neuroradiology, Department of Radiology (S.P.P., E.Y.), The Manton Center for Orphan Disease Research (D.E.-F., R.C.Y., S.K.A.), Rosamund Stone Zander Translational Neuroscience Center (M.S.), and Division of Genetics and Genomics (D.E.-F., R.C.Y., S.K.A.), Boston Children's Hospital, Harvard Medical School, MA
| | - Sanjay P Prabhu
- From the Department of Neurology (D.E.-F., J.E.A., M.Z., G.G., C.J., A.D., A.S., M.S.), and Division of Neuroradiology, Department of Radiology (S.P.P., E.Y.), The Manton Center for Orphan Disease Research (D.E.-F., R.C.Y., S.K.A.), Rosamund Stone Zander Translational Neuroscience Center (M.S.), and Division of Genetics and Genomics (D.E.-F., R.C.Y., S.K.A.), Boston Children's Hospital, Harvard Medical School, MA
| | - Mustafa Sahin
- From the Department of Neurology (D.E.-F., J.E.A., M.Z., G.G., C.J., A.D., A.S., M.S.), and Division of Neuroradiology, Department of Radiology (S.P.P., E.Y.), The Manton Center for Orphan Disease Research (D.E.-F., R.C.Y., S.K.A.), Rosamund Stone Zander Translational Neuroscience Center (M.S.), and Division of Genetics and Genomics (D.E.-F., R.C.Y., S.K.A.), Boston Children's Hospital, Harvard Medical School, MA
| | - Edward Yang
- From the Department of Neurology (D.E.-F., J.E.A., M.Z., G.G., C.J., A.D., A.S., M.S.), and Division of Neuroradiology, Department of Radiology (S.P.P., E.Y.), The Manton Center for Orphan Disease Research (D.E.-F., R.C.Y., S.K.A.), Rosamund Stone Zander Translational Neuroscience Center (M.S.), and Division of Genetics and Genomics (D.E.-F., R.C.Y., S.K.A.), Boston Children's Hospital, Harvard Medical School, MA
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22
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Ebrahimi-Fakhari D, Alecu JE, Brechmann B, Ziegler M, Eberhardt K, Jumo H, D’Amore A, Habibzadeh P, Faghihi MA, De Bleecker JL, Vuillaumier-Barrot S, Auvin S, Santorelli FM, Neuser S, Popp B, Yang E, Barrett L, Davies AK, Saffari A, Hirst J, Sahin M. High-throughput imaging of ATG9A distribution as a diagnostic functional assay for adaptor protein complex 4-associated hereditary spastic paraplegia. Brain Commun 2021; 3:fcab221. [PMID: 34729478 PMCID: PMC8557665 DOI: 10.1093/braincomms/fcab221] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 08/05/2021] [Accepted: 08/19/2021] [Indexed: 01/09/2023] Open
Abstract
Adaptor protein complex 4-associated hereditary spastic paraplegia is caused by biallelic loss-of-function variants in AP4B1, AP4M1, AP4E1 or AP4S1, which constitute the four subunits of this obligate complex. While the diagnosis of adaptor protein complex 4-associated hereditary spastic paraplegia relies on molecular testing, the interpretation of novel missense variants remains challenging. Here, we address this diagnostic gap by using patient-derived fibroblasts to establish a functional assay that measures the subcellular localization of ATG9A, a transmembrane protein that is sorted by adaptor protein complex 4. Using automated high-throughput microscopy, we determine the ratio of the ATG9A fluorescence in the trans-Golgi-network versus cytoplasm and ascertain that this metric meets standards for screening assays (Z'-factor robust >0.3, strictly standardized mean difference >3). The 'ATG9A ratio' is increased in fibroblasts of 18 well-characterized adaptor protein complex 4-associated hereditary spastic paraplegia patients [mean: 1.54 ± 0.13 versus 1.21 ± 0.05 (standard deviation) in controls] and receiver-operating characteristic analysis demonstrates robust diagnostic power (area under the curve: 0.85, 95% confidence interval: 0.849-0.852). Using fibroblasts from two individuals with atypical clinical features and novel biallelic missense variants of unknown significance in AP4B1, we show that our assay can reliably detect adaptor protein complex 4 function. Our findings establish the 'ATG9A ratio' as a diagnostic marker of adaptor protein complex 4-associated hereditary spastic paraplegia.
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Affiliation(s)
- Darius Ebrahimi-Fakhari
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- The Manton Center for Orphan Disease Research, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Julian E Alecu
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Barbara Brechmann
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Division of Neuropediatrics and Inherited Metabolic Diseases, Center for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Marvin Ziegler
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Ruprecht-Karls University Heidelberg, Medical School, 69120 Heidelberg, Germany
| | - Kathrin Eberhardt
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Hellen Jumo
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Angelica D’Amore
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Parham Habibzadeh
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, 71347 Shiraz, Iran
| | - Mohammad Ali Faghihi
- Department of Psychiatry and Behavioral Sciences, University of Miami, Miami, FL 33136, USA
| | - Jan L De Bleecker
- Department of Neurology, Ghent University Hospital, 9000 Ghent, Belgium
| | | | - Stéphane Auvin
- Pediatric Neurology Department, AP-HP, Robert Debré Hospital, 75019 Paris, France
| | - Filippo M Santorelli
- Department of Molecular Medicine, IRCCS Fondazione Stella Maris, 56128 Pisa, Italy
| | - Sonja Neuser
- Institute of Human Genetics, University of Leipzig Medical Center, 04103 Leipzig, Germany
| | - Bernt Popp
- Institute of Human Genetics, University of Leipzig Medical Center, 04103 Leipzig, Germany
| | - Edward Yang
- Division of Neuroradiology, Department of Radiology, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Lee Barrett
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Alexandra K Davies
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Afshin Saffari
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Division of Neuropediatrics and Inherited Metabolic Diseases, Center for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Jennifer Hirst
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Mustafa Sahin
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children’s Hospital, Boston, MA 02115, USA
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23
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Jordan C, Geisel G, Alecu JE, Zhang B, Sahin M, Ebrahimi-Fakhari D. Disease Severity and Motor Impairment Correlate With Health-Related Quality of Life in AP-4-Associated Hereditary Spastic Paraplegia. NEUROLOGY-GENETICS 2021; 7:e605. [PMID: 34295967 PMCID: PMC8293284 DOI: 10.1212/nxg.0000000000000605] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 04/23/2021] [Indexed: 11/15/2022]
Abstract
Objective AP-4-associated hereditary spastic paraplegia (AP-4-HSP) is a childhood-onset neurogenetic disease and mimic of cerebral palsy. Data on health-related quality of life (HRQoL) are lacking. To establish a metric for HRQoL and caregiver priorities, we used the Caregiver Priorities and Child Health Index of Life with Disabilities (CPCHILD) questionnaire to assess HRQoL in correlation with disease severity in 64 patients with AP-4-HSP. Methods A cross-sectional analysis of caregiver-reported HRQoL was performed using the CPCHILD questionnaire in combination with a detailed clinical characterization. Results HRQoL was impaired in all domains in patients with AP-4-HSP (mean score: 59.6 ± 12.6 [SD]), with no significant difference between the 4 subtypes. Age, as a surrogate for disease duration, and Spastic Paraplegia Rating Scale scores, as an indicator for corticospinal tract dysfunction and motor impairment, correlated with lower CPCHILD scores (Pearson r = −0.31, p = 0.01 and r = −0.52, p < 0.0001, respectively). Patients with tetraplegia showed lower CPCHILD scores compared with individuals with diplegia or no spasticity. Wheelchair dependence reduced HRQoL in all domains. The presence of seizures, including medically refractory epilepsy, was not associated with lower CPCHILD scores. Standardized assessment of caregiver priorities identified several areas of high importance to HRQoL. Conclusions We show that the CPCHILD questionnaire, developed for use in children with cerebral palsy, can be used to assess HRQoL in patients with childhood-onset complex hereditary spastic paraplegia. HRQoL is reduced in patients with AP-4-HSP and correlates with the degree of motor impairment. These results provide a framework for medical decision making and a baseline for the future development of treatment guidelines and interventional trials.
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Affiliation(s)
- Catherine Jordan
- Department of Neurology and The F.M. Kirby Neurobiology Center (C.J., G.G., J.E.A., M.S., D.E.-F.), Rosamund Stone Zander Translational Neuroscience Center (G.G., M.S.), and ICCTR Biostatistics and Research Design Center (B.Z.), Boston Children's Hospital, Harvard Medical School, MA
| | - Gregory Geisel
- Department of Neurology and The F.M. Kirby Neurobiology Center (C.J., G.G., J.E.A., M.S., D.E.-F.), Rosamund Stone Zander Translational Neuroscience Center (G.G., M.S.), and ICCTR Biostatistics and Research Design Center (B.Z.), Boston Children's Hospital, Harvard Medical School, MA
| | - Julian E Alecu
- Department of Neurology and The F.M. Kirby Neurobiology Center (C.J., G.G., J.E.A., M.S., D.E.-F.), Rosamund Stone Zander Translational Neuroscience Center (G.G., M.S.), and ICCTR Biostatistics and Research Design Center (B.Z.), Boston Children's Hospital, Harvard Medical School, MA
| | - Bo Zhang
- Department of Neurology and The F.M. Kirby Neurobiology Center (C.J., G.G., J.E.A., M.S., D.E.-F.), Rosamund Stone Zander Translational Neuroscience Center (G.G., M.S.), and ICCTR Biostatistics and Research Design Center (B.Z.), Boston Children's Hospital, Harvard Medical School, MA
| | - Mustafa Sahin
- Department of Neurology and The F.M. Kirby Neurobiology Center (C.J., G.G., J.E.A., M.S., D.E.-F.), Rosamund Stone Zander Translational Neuroscience Center (G.G., M.S.), and ICCTR Biostatistics and Research Design Center (B.Z.), Boston Children's Hospital, Harvard Medical School, MA
| | - Darius Ebrahimi-Fakhari
- Department of Neurology and The F.M. Kirby Neurobiology Center (C.J., G.G., J.E.A., M.S., D.E.-F.), Rosamund Stone Zander Translational Neuroscience Center (G.G., M.S.), and ICCTR Biostatistics and Research Design Center (B.Z.), Boston Children's Hospital, Harvard Medical School, MA
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Toupenet Marchesi L, Leblanc M, Stevanin G. Current Knowledge of Endolysosomal and Autophagy Defects in Hereditary Spastic Paraplegia. Cells 2021; 10:cells10071678. [PMID: 34359848 PMCID: PMC8307360 DOI: 10.3390/cells10071678] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 06/26/2021] [Accepted: 06/29/2021] [Indexed: 12/25/2022] Open
Abstract
Hereditary spastic paraplegia (HSP) refers to a group of neurological disorders involving the degeneration of motor neurons. Due to their clinical and genetic heterogeneity, finding common effective therapeutics is difficult. Therefore, a better understanding of the common pathological mechanisms is necessary. The role of several HSP genes/proteins is linked to the endolysosomal and autophagic pathways, suggesting a functional convergence. Furthermore, impairment of these pathways is particularly interesting since it has been linked to other neurodegenerative diseases, which would suggest that the nervous system is particularly sensitive to the disruption of the endolysosomal and autophagic systems. In this review, we will summarize the involvement of HSP proteins in the endolysosomal and autophagic pathways in order to clarify their functioning and decipher some of the pathological mechanisms leading to HSP.
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Affiliation(s)
- Liriopé Toupenet Marchesi
- Institut du Cerveau—Paris Brain Institute—ICM, INSERM, CNRS, APHP, Sorbonne Université, Pitié-Salpêtrière Hospital, 75013 Paris, France; (L.T.M.); (M.L.)
- Neurogenetics Team, EPHE, Paris Sciences Lettres Research University, 75000 Paris, France
| | - Marion Leblanc
- Institut du Cerveau—Paris Brain Institute—ICM, INSERM, CNRS, APHP, Sorbonne Université, Pitié-Salpêtrière Hospital, 75013 Paris, France; (L.T.M.); (M.L.)
- Neurogenetics Team, EPHE, Paris Sciences Lettres Research University, 75000 Paris, France
| | - Giovanni Stevanin
- Institut du Cerveau—Paris Brain Institute—ICM, INSERM, CNRS, APHP, Sorbonne Université, Pitié-Salpêtrière Hospital, 75013 Paris, France; (L.T.M.); (M.L.)
- Neurogenetics Team, EPHE, Paris Sciences Lettres Research University, 75000 Paris, France
- Correspondence:
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25
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Crawley O, Grill B. Autophagy in axonal and presynaptic development. Curr Opin Neurobiol 2021; 69:139-148. [PMID: 33940492 DOI: 10.1016/j.conb.2021.03.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 03/17/2021] [Accepted: 03/21/2021] [Indexed: 10/21/2022]
Abstract
The study of autophagy in the nervous system has predominantly centered on degeneration. Evidence is now cementing crucial roles for autophagy in neuronal development and growth, especially in axonal and presynaptic compartments. A picture is emerging that autophagy typically promotes the growth of axons and reduces presynaptic stability. Nonetheless, these are not rigid principles, and it remains unclear why autophagy does not always display these relationships during axonal and presynaptic development. Recent progress has identified mechanisms underlying spatiotemporal control of autophagy in neurons and begun to unravel how autophagy is integrated with other cellular processes, such as proteasomal degradation and axon guidance. Ultimately, understanding how autophagy is regulated and its role in the developing nervous system is key to comprehending how the nervous system assembles its stereotyped yet plastic configuration. It is also likely to inform how we think about neurodevelopmental disorders and neurodegenerative diseases.
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Affiliation(s)
- Oliver Crawley
- Unidad de Neurobiología Celular y de Sistemas, Instituto de Neurociencias (CSIC-UMH), San Juan de Alicante, 03550, Spain.
| | - Brock Grill
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, 98199, USA; Department of Pediatrics, University of Washington School of Medicine, Seattle, WA, USA; Department of Pharmacology, University of Washington School of Medicine, Seattle, WA, USA.
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26
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Rudenskaya GE, Guseva DM, Mironovich OL, Kadnikova VA, Dadali EL, Komar'kov IF, Novoselova OG, Ryzhkova OP. [AP4-assocated hereditary spastic paraplegias]. Zh Nevrol Psikhiatr Im S S Korsakova 2021; 121:71-78. [PMID: 33728854 DOI: 10.17116/jnevro202112102171] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE In the course of studies of spastic paraplegias in Russian patients to detect AP4-associated forms, estimate their proportion in the total SPG group and analyze clinical and molecular characteristics. MATERIAL AND METHODS Five families of Russian ethnicity: four with SPG47, one with SPG51 (4 girls and a boy aged 2.5-9 years) were studied. Clinical and genealogical methods, whole-exome sequencing (WES) and verification by familial Sanger sequencing were used. RESULTS In our total group, including 118 families with 21 different forms, SPG AP4-associated forms accounted for 4.2% owing mainly to SPG47 (3.4%, 5th place in SPG structure; 20% and 2nd place in AE subgroup.) In non-consanguineous, unrelated SPG47 families three patients had identical genotypes: homozygosity for an earlier reported mutation c.1160_1161 delCA (p.Thr387ArgfsTer30) in AP4B1 exon 6; the 4th patient was compound-heterozygous for the same mutation and novel c.1240C>T (p.Gln414Ter) in exon 7. Frequency of c.1160_1161 delCA may be caused by founder effect in Slavic populations though the idea needs additional studies. The SPG51 patient was compound heterozygous for novel AP4E1 mutations c.2604delA (p.Ser868fs) and c.3346A>G (p.Arg1116Gly). Parent's heterozygosity in all cases was confirmed by Sanger sequencing. Phenotypes were typical: early development delay, muscle hypotony transforming into sever spasticity, mental deficiency, microceplaly (in all SPG47 cases), epilepsy (in 3 SPG47 and SPG51 cases), MRI changes, mainly hydrocephalus and/or hypoplasia of corpus callosum (in 3 SPG47 cases) and few extraneural signs. CONCLUSION AP4-associated SPG should be taken into consideration in patients with early-onset severe nervous diseases mimicking non-genetic organic CNS disorders and massive exome sequencing (WES or other variants) should be performed.
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Affiliation(s)
| | - D M Guseva
- Research Centre for Medical Genetics, Moscow, Russia
| | | | - V A Kadnikova
- Research Centre for Medical Genetics, Moscow, Russia
| | - E L Dadali
- Research Centre for Medical Genetics, Moscow, Russia
| | | | | | - O P Ryzhkova
- Research Centre for Medical Genetics, Moscow, Russia
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27
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Akter H, Hossain MS, Dity NJ, Rahaman MA, Furkan Uddin KM, Nassir N, Begum G, Hameid RA, Islam MS, Tusty TA, Basiruzzaman M, Sarkar S, Islam M, Jahan S, Lim ET, Woodbury-Smith M, Stavropoulos DJ, O'Rielly DD, Berdeiv BK, Nurun Nabi AHM, Ahsan MN, Scherer SW, Uddin M. Whole exome sequencing uncovered highly penetrant recessive mutations for a spectrum of rare genetic pediatric diseases in Bangladesh. NPJ Genom Med 2021; 6:14. [PMID: 33594065 PMCID: PMC7887195 DOI: 10.1038/s41525-021-00173-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 01/06/2021] [Indexed: 01/31/2023] Open
Abstract
Collectively, rare genetic diseases affect a significant number of individuals worldwide. In this study, we have conducted whole-exome sequencing (WES) and identified underlying pathogenic or likely pathogenic variants in five children with rare genetic diseases. We present evidence for disease-causing autosomal recessive variants in a range of disease-associated genes such as DHH-associated 46,XY gonadal dysgenesis (GD) or 46,XY sex reversal 7, GNPTAB-associated mucolipidosis II alpha/beta (ML II), BBS1-associated Bardet-Biedl Syndrome (BBS), SURF1-associated Leigh Syndrome (LS) and AP4B1-associated spastic paraplegia-47 (SPG47) in unrelated affected members from Bangladesh. Our analysis pipeline detected three homozygous mutations, including a novel c. 863 G > C (p.Pro288Arg) variant in DHH, and two compound heterozygous variants, including two novel variants: c.2972dupT (p.Met991Ilefs*) in GNPTAB and c.229 G > C (p.Gly77Arg) in SURF1. All mutations were validated by Sanger sequencing. Collectively, this study adds to the genetic heterogeneity of rare genetic diseases and is the first report elucidating the genetic profile of (consanguineous and nonconsanguineous) rare genetic diseases in the Bangladesh population.
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Affiliation(s)
- Hosneara Akter
- Genetics and Genomic Medicine Centre, NeuroGen Children's Healthcare, Dhaka, Bangladesh
- Department of Biochemistry and Molecular Biology, University of Dhaka, Dhaka, Bangladesh
| | | | - Nushrat Jahan Dity
- Genetics and Genomic Medicine Centre, NeuroGen Children's Healthcare, Dhaka, Bangladesh
| | - Md Atikur Rahaman
- Genetics and Genomic Medicine Centre, NeuroGen Children's Healthcare, Dhaka, Bangladesh
| | - K M Furkan Uddin
- Genetics and Genomic Medicine Centre, NeuroGen Children's Healthcare, Dhaka, Bangladesh
| | - Nasna Nassir
- College of Medicine, Mohammed Bin Rashid University of Medicine and Health Science, Dubai, UAE
| | - Ghausia Begum
- College of Medicine, Mohammed Bin Rashid University of Medicine and Health Science, Dubai, UAE
| | - Reem Abdel Hameid
- College of Medicine, Mohammed Bin Rashid University of Medicine and Health Science, Dubai, UAE
| | | | - Tahrima Arman Tusty
- Department of Genetic Engineering & Biotechnology, University of Dhaka, Dhaka, Bangladesh
| | - Mohammad Basiruzzaman
- Genetics and Genomic Medicine Centre, NeuroGen Children's Healthcare, Dhaka, Bangladesh
- Department of Child Neurology, NeuroGen Children's Healthcare, Dhaka, Bangladesh
| | - Shaoli Sarkar
- Genetics and Genomic Medicine Centre, NeuroGen Children's Healthcare, Dhaka, Bangladesh
- Department of Child Neurology, NeuroGen Children's Healthcare, Dhaka, Bangladesh
| | - Mazharul Islam
- Genetics and Genomic Medicine Centre, NeuroGen Children's Healthcare, Dhaka, Bangladesh
- Department of Child Neurology, NeuroGen Children's Healthcare, Dhaka, Bangladesh
| | - Sharmin Jahan
- Department of Endocrinology & Metabolism, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh
| | - Elaine T Lim
- Department of Genetics, Harvard Medical School, Boston, USA
| | - Marc Woodbury-Smith
- The Centre for Applied Genomics, The Hospital for Sick Children, Toronto, Canada
- Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Dimitri James Stavropoulos
- Genome Diagnostics, Department of Pediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Canada
| | | | - Bakhrom K Berdeiv
- College of Medicine, Mohammed Bin Rashid University of Medicine and Health Science, Dubai, UAE
| | - A H M Nurun Nabi
- Department of Biochemistry and Molecular Biology, University of Dhaka, Dhaka, Bangladesh
| | - Mohammed Nazmul Ahsan
- Department of Genetic Engineering & Biotechnology, University of Dhaka, Dhaka, Bangladesh
| | - Stephen W Scherer
- The Centre for Applied Genomics, The Hospital for Sick Children, Toronto, Canada
- McLaughlin Centre and Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Mohammed Uddin
- College of Medicine, Mohammed Bin Rashid University of Medicine and Health Science, Dubai, UAE.
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The role of AP-4 in cargo export from the trans-Golgi network and hereditary spastic paraplegia. Biochem Soc Trans 2020; 48:1877-1888. [PMID: 33084855 DOI: 10.1042/bst20190664] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 09/22/2020] [Accepted: 09/29/2020] [Indexed: 01/02/2023]
Abstract
Heterotetrameric adaptor protein (AP) complexes play key roles in protein sorting and transport vesicle formation in the endomembrane system of eukaryotic cells. One of these complexes, AP-4, was identified over 20 years ago but, up until recently, its function remained unclear. AP-4 associates with the trans-Golgi network (TGN) through interaction with small GTPases of the ARF family and recognizes transmembrane proteins (i.e. cargos) having specific sorting signals in their cytosolic domains. Recent studies identified accessory proteins (tepsin, RUSC2 and the FHF complex) that co-operate with AP-4, and cargos (amyloid precursor protein, ATG9A and SERINC3/5) that are exported from the TGN in an AP-4-dependent manner. Defective export of ATG9A from the TGN in AP-4-deficient cells was shown to reduce ATG9A delivery to pre-autophagosomal structures, impairing autophagosome formation and/or maturation. In addition, mutations in AP-4-subunit genes were found to cause neurological dysfunction in mice and a form of complicated hereditary spastic paraplegia referred to as 'AP-4-deficiency syndrome' in humans. These findings demonstrated that mammalian AP-4 is required for the development and function of the central nervous system, possibly through its role in the sorting of ATG9A for the maintenance of autophagic homeostasis. In this article, we review the properties and functions of AP-4, and discuss how they might explain the clinical features of AP-4 deficiency.
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29
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Ebrahimi-Fakhari D, Teinert J, Behne R, Wimmer M, D'Amore A, Eberhardt K, Brechmann B, Ziegler M, Jensen DM, Nagabhyrava P, Geisel G, Carmody E, Shamshad U, Dies KA, Yuskaitis CJ, Salussolia CL, Ebrahimi-Fakhari D, Pearson TS, Saffari A, Ziegler A, Kölker S, Volkmann J, Wiesener A, Bearden DR, Lakhani S, Segal D, Udwadia-Hegde A, Martinuzzi A, Hirst J, Perlman S, Takiyama Y, Xiromerisiou G, Vill K, Walker WO, Shukla A, Dubey Gupta R, Dahl N, Aksoy A, Verhelst H, Delgado MR, Kremlikova Pourova R, Sadek AA, Elkhateeb NM, Blumkin L, Brea-Fernández AJ, Dacruz-Álvarez D, Smol T, Ghoumid J, Miguel D, Heine C, Schlump JU, Langen H, Baets J, Bulk S, Darvish H, Bakhtiari S, Kruer MC, Lim-Melia E, Aydinli N, Alanay Y, El-Rashidy O, Nampoothiri S, Patel C, Beetz C, Bauer P, Yoon G, Guillot M, Miller SP, Bourinaris T, Houlden H, Robelin L, Anheim M, Alamri AS, Mahmoud AAH, Inaloo S, Habibzadeh P, Faghihi MA, Jansen AC, Brock S, Roubertie A, Darras BT, Agrawal PB, Santorelli FM, Gleeson J, Zaki MS, Sheikh SI, Bennett JT, Sahin M. Defining the clinical, molecular and imaging spectrum of adaptor protein complex 4-associated hereditary spastic paraplegia. Brain 2020; 143:2929-2944. [PMID: 32979048 PMCID: PMC7780481 DOI: 10.1093/brain/awz307] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 07/25/2019] [Accepted: 08/16/2019] [Indexed: 12/21/2022] Open
Abstract
Bi-allelic loss-of-function variants in genes that encode subunits of the adaptor protein complex 4 (AP-4) lead to prototypical yet poorly understood forms of childhood-onset and complex hereditary spastic paraplegia: SPG47 (AP4B1), SPG50 (AP4M1), SPG51 (AP4E1) and SPG52 (AP4S1). Here, we report a detailed cross-sectional analysis of clinical, imaging and molecular data of 156 patients from 101 families. Enrolled patients were of diverse ethnic backgrounds and covered a wide age range (1.0-49.3 years). While the mean age at symptom onset was 0.8 ± 0.6 years [standard deviation (SD), range 0.2-5.0], the mean age at diagnosis was 10.2 ± 8.5 years (SD, range 0.1-46.3). We define a set of core features: early-onset developmental delay with delayed motor milestones and significant speech delay (50% non-verbal); intellectual disability in the moderate to severe range; mild hypotonia in infancy followed by spastic diplegia (mean age: 8.4 ± 5.1 years, SD) and later tetraplegia (mean age: 16.1 ± 9.8 years, SD); postnatal microcephaly (83%); foot deformities (69%); and epilepsy (66%) that is intractable in a subset. At last follow-up, 36% ambulated with assistance (mean age: 8.9 ± 6.4 years, SD) and 54% were wheelchair-dependent (mean age: 13.4 ± 9.8 years, SD). Episodes of stereotypic laughing, possibly consistent with a pseudobulbar affect, were found in 56% of patients. Key features on neuroimaging include a thin corpus callosum (90%), ventriculomegaly (65%) often with colpocephaly, and periventricular white-matter signal abnormalities (68%). Iron deposition and polymicrogyria were found in a subset of patients. AP4B1-associated SPG47 and AP4M1-associated SPG50 accounted for the majority of cases. About two-thirds of patients were born to consanguineous parents, and 82% carried homozygous variants. Over 70 unique variants were present, the majority of which are frameshift or nonsense mutations. To track disease progression across the age spectrum, we defined the relationship between disease severity as measured by several rating scales and disease duration. We found that the presence of epilepsy, which manifested before the age of 3 years in the majority of patients, was associated with worse motor outcomes. Exploring genotype-phenotype correlations, we found that disease severity and major phenotypes were equally distributed among the four subtypes, establishing that SPG47, SPG50, SPG51 and SPG52 share a common phenotype, an 'AP-4 deficiency syndrome'. By delineating the core clinical, imaging, and molecular features of AP-4-associated hereditary spastic paraplegia across the age spectrum our results will facilitate early diagnosis, enable counselling and anticipatory guidance of affected families and help define endpoints for future interventional trials.
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Affiliation(s)
- Darius Ebrahimi-Fakhari
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Julian Teinert
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Division of Child Neurology and Metabolic Medicine, Centre for Paediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Robert Behne
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Department of Neurology, University Hospital Würzburg, Würzburg, Germany
| | - Miriam Wimmer
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Angelica D'Amore
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Molecular Medicine, IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Kathrin Eberhardt
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Barbara Brechmann
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Marvin Ziegler
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Dana M Jensen
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA, USA
| | - Premsai Nagabhyrava
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Gregory Geisel
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Erin Carmody
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Uzma Shamshad
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Kira A Dies
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Christopher J Yuskaitis
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Catherine L Salussolia
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Daniel Ebrahimi-Fakhari
- Pediatric Neurology, Saarland University Medical Center, Homburg/Saar, Germany
- Department of General Pediatrics, University Children's Hospital Muenster, Muenster, Germany
| | - Toni S Pearson
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Afshin Saffari
- Division of Child Neurology and Metabolic Medicine, Centre for Paediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Andreas Ziegler
- Division of Child Neurology and Metabolic Medicine, Centre for Paediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Stefan Kölker
- Division of Child Neurology and Metabolic Medicine, Centre for Paediatric and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Jens Volkmann
- Department of Neurology, University Hospital Würzburg, Würzburg, Germany
| | - Antje Wiesener
- Institute of Human Genetics, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - David R Bearden
- Child Neurology, University of Rochester School of Medicine, Rochester, NY, USA
| | - Shenela Lakhani
- Center for Neurogenetics, Weill Cornell Medical College, New York, NY, USA
| | - Devorah Segal
- Center for Neurogenetics, Weill Cornell Medical College, New York, NY, USA
- Division of Child Neurology, Weill Cornell Medicine, New York City, NY, USA
| | - Anaita Udwadia-Hegde
- Department of Pediatric Neurology, Jaslok Hospital and Research Centre, Mumbai, India
| | - Andrea Martinuzzi
- Scientific Institute, IRCCS E. Medea, Unità Operativa Conegliano, Treviso, Italy
| | - Jennifer Hirst
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Seth Perlman
- Division of Neurology, Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | | | | | - Katharina Vill
- Pediatric Neurology and Developmental Medicine, Dr. v. Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
| | - William O Walker
- Department of Pediatrics, Seattle Children's Hospital, University of Washington School of Medicine, Seattle, WA, USA
| | - Anju Shukla
- Department of Medical Genetics, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, India
| | | | - Niklas Dahl
- Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Ayse Aksoy
- Pediatric Neurology, Dr. Sami Ulus Hospital, Ankara, Turkey
| | - Helene Verhelst
- Pediatric Neurology, Ghent University Hospital, Ghent, Belgium
| | - Mauricio R Delgado
- Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Radka Kremlikova Pourova
- Department of Biology and Medical Genetics, Second Medical Faculty, Charles University and UH Motol, Prague, Czech Republic
| | - Abdelrahim A Sadek
- Pediatric Neurology, Faculty of Medicine, Sohag University, Sohag, Egypt
| | | | - Lubov Blumkin
- Movement Disorders Clinic, Pediatric Neurology Unit, Wolfson Medical Center, Holon, Sackler School of Medicine, Tel-Aviv University, Israel
| | | | - David Dacruz-Álvarez
- Neurología Pediátrica, Complexo Hospitalario Universitario, Santiago de Compostela, Spain
| | - Thomas Smol
- CHU Lille, Institut de Génétique Médicale, RADEME, Lille, France
| | - Jamal Ghoumid
- CHU Lille, Institut de Génétique Médicale, RADEME, Lille, France
| | - Diego Miguel
- Serviço de Genética Médica, Universidade Federal da Bahia, Salvador, Brazil
| | - Constanze Heine
- Institute of Human Genetics, University Hospital Leipzig, Leipzig, Germany
| | | | | | - Jonathan Baets
- Neurogenetics Group and Neuromuscular Reference Center, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium
| | - Saskia Bulk
- Medical Genetics, Centre Hospitalier Universitaire de Liège, Liège, Belgium
| | - Hossein Darvish
- Cancer Research Center and Department of Medical Genetics, Semnan University of Medical Sciences, Semnan, Iran
| | - Somayeh Bakhtiari
- Barrow Neurological Institute, Phoenix Children's Hospital, Phoenix, AZ, USA
| | - Michael C Kruer
- Barrow Neurological Institute, Phoenix Children's Hospital, Phoenix, AZ, USA
| | - Elizabeth Lim-Melia
- Pediatric Medical Genetics, Maria Fareri Children's Hospital, Valhalla, NY, USA
| | - Nur Aydinli
- Pediatric Genetics, Department of Pediatrics, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
| | - Yasemin Alanay
- Pediatric Neurology, Istanbul Medical Faculty, Istanbul, Turkey
| | | | | | - Chirag Patel
- Genetic Health Queensland, Royal Brisbane and Women's Hospital, Brisbane, Australia
| | | | | | - Grace Yoon
- Division of Clinical and Metabolic Genetics, Department of Paediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - Mireille Guillot
- Department of Paediatrics, The Hospital for Sick Children and The University of Toronto, Toronto, Canada
| | - Steven P Miller
- Department of Paediatrics, The Hospital for Sick Children and The University of Toronto, Toronto, Canada
| | - Thomas Bourinaris
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Henry Houlden
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Laura Robelin
- Service de Neurologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Mathieu Anheim
- Service de Neurologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Abdullah S Alamri
- Pediatric Neurology, National Neuroscience Institute, King Fahad Medical City, Riyadh, Saudi Arabia
| | - Adel A H Mahmoud
- Pediatrics, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Soroor Inaloo
- Neonatal Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Parham Habibzadeh
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad Ali Faghihi
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
- Center for Therapeutic Innovation and Department of Psychiatry and Behavioral Sciences, University of Miami, Miami, FL, USA
| | - Anna C Jansen
- Pediatric Neurology Unit, Department of Pediatrics, UZ Brussel, Brussels, Belgium
| | - Stefanie Brock
- Pediatric Neurology Unit, Department of Pediatrics, UZ Brussel, Brussels, Belgium
| | | | - Basil T Darras
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Pankaj B Agrawal
- Divisions of Newborn Medicine and Genetics and Genomics, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | | | - Joseph Gleeson
- Rady Children's Institute for Genomic Medicine, Rady Children's Hospital, San Diego, CA, USA
| | - Maha S Zaki
- Clinical Genetics, Human Genetics and Genome Research Division, National Research Centre, Cairo, Egypt
| | | | - James T Bennett
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA, USA
| | - Mustafa Sahin
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
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30
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Gadbery JE, Abraham A, Needle CD, Moth C, Sheehan J, Capra JA, Jackson LP. Integrating structural and evolutionary data to interpret variation and pathogenicity in adapter protein complex 4. Protein Sci 2020; 29:1535-1549. [PMID: 32285480 PMCID: PMC7255511 DOI: 10.1002/pro.3870] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/01/2020] [Accepted: 04/10/2020] [Indexed: 12/13/2022]
Abstract
Genetic variation in the membrane trafficking adapter protein complex 4 (AP-4) can result in pathogenic neurological phenotypes including microencephaly, spastic paraplegias, epilepsy, and other developmental defects. We lack molecular mechanisms responsible for impaired AP-4 function arising from genetic variation, because AP-4 remains poorly understood structurally. Here, we analyze patterns of AP-4 genetic evolution and conservation to identify regions that are likely important for function and thus more susceptible to pathogenic variation. We map known variants onto an AP-4 homology model and predict the likelihood of pathogenic variation at a given location on the structure of AP-4. We find significant clustering of likely pathogenic variants located at the interface between the β4 and N-μ4 subunits, as well as throughout the C-μ4 subunit. Our work offers an integrated perspective on how genetic and evolutionary forces affect AP-4 structure and function. As more individuals with uncharacterized AP-4 variants are identified, our work provides a foundation upon which their functional effects and disease relevance can be interpreted.
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Affiliation(s)
- John E. Gadbery
- Department of Biological SciencesVanderbilt UniversityNashvilleTennesseeUSA
| | - Abin Abraham
- Vanderbilt Genetics InstituteVanderbilt University School of MedicineNashvilleTennesseeUSA
| | - Carli D. Needle
- Department of Biological SciencesVanderbilt UniversityNashvilleTennesseeUSA
| | - Christopher Moth
- Center for Structural BiologyVanderbilt UniversityNashvilleTennesseeUSA
| | - Jonathan Sheehan
- Center for Structural BiologyVanderbilt UniversityNashvilleTennesseeUSA
- Department of BiochemistryVanderbilt University School of MedicineNashvilleTennesseeUSA
| | - John A. Capra
- Department of Biological SciencesVanderbilt UniversityNashvilleTennesseeUSA
- Vanderbilt Genetics InstituteVanderbilt University School of MedicineNashvilleTennesseeUSA
- Center for Structural BiologyVanderbilt UniversityNashvilleTennesseeUSA
- Department of Biomedical InformaticsVanderbilt University School of MedicineNashvilleTennesseeUSA
| | - Lauren P. Jackson
- Department of Biological SciencesVanderbilt UniversityNashvilleTennesseeUSA
- Center for Structural BiologyVanderbilt UniversityNashvilleTennesseeUSA
- Department of BiochemistryVanderbilt University School of MedicineNashvilleTennesseeUSA
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31
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Mattera R, Williamson CD, Ren X, Bonifacino JS. The FTS-Hook-FHIP (FHF) complex interacts with AP-4 to mediate perinuclear distribution of AP-4 and its cargo ATG9A. Mol Biol Cell 2020; 31:963-979. [PMID: 32073997 PMCID: PMC7185972 DOI: 10.1091/mbc.e19-11-0658] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 02/05/2020] [Accepted: 02/12/2020] [Indexed: 01/08/2023] Open
Abstract
The heterotetrameric adaptor protein complex 4 (AP-4) is a component of a protein coat associated with the trans-Golgi network (TGN). Mutations in AP-4 subunits cause a complicated form of autosomal-recessive hereditary spastic paraplegia termed AP-4-deficiency syndrome. Recent studies showed that AP-4 mediates export of the transmembrane autophagy protein ATG9A from the TGN to preautophagosomal structures. To identify additional proteins that cooperate with AP-4 in ATG9A trafficking, we performed affinity purification-mass spectrometry followed by validation of the hits by biochemical and functional analyses. This approach resulted in the identification of the fused toes homolog-Hook-FHIP (FHF) complex as a novel AP-4 accessory factor. We found that the AP-4-FHF interaction is mediated by direct binding of the AP-4 μ4 subunit to coiled-coil domains in the Hook1 and Hook2 subunits of FHF. Knockdown of FHF subunits resulted in dispersal of AP-4 and ATG9A from the perinuclear region of the cell, consistent with the previously demonstrated role of the FHF complex in coupling organelles to the microtubule (MT) retrograde motor dynein-dynactin. These findings thus uncover an additional mechanism for the distribution of ATG9A within cells and provide further evidence for a role of protein coats in coupling transport vesicles to MT motors.
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Affiliation(s)
- Rafael Mattera
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Chad D. Williamson
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
| | - Xuefeng Ren
- Department of Molecular and Cell Biology and California Institute of Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720
| | - Juan S. Bonifacino
- Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892
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Ruan WC, Wang J, Yu YL, Che YP, Ding L, Li CX, Wang XD, Li HF. Novel variants in AP4B1 cause spastic tetraplegia, moderate psychomotor development delay and febrile seizures in a Chinese patient: a case report. BMC MEDICAL GENETICS 2020; 21:51. [PMID: 32171285 PMCID: PMC7071676 DOI: 10.1186/s12881-020-0988-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 02/28/2020] [Indexed: 11/10/2022]
Abstract
Introduction The AP4B1 gene encodes a subunit of adaptor protein complex-4 (AP4), a component of intracellular transportation of proteins which plays important roles in neurons. Bi-allelic mutations in AP4B1 cause autosomal recessive spastic paraplegia-47(SPG47). Case presentation Here we present a Chinese patient with spastic tetraplegia, moderate psychomotor development delay and febrile seizures plus. Brain MRIs showed dilated supratentorial ventricle, thin posterior and splenium part of corpus callosum. The patient had little progress through medical treatments and rehabilitating regimens. Whole exome sequencing identified novel compound heterozygous truncating variants c.1207C > T (p.Gln403*) and c.52_53delAC (p.Cys18Glnfs*7) in AP4B1 gene. Causal mutations in AP4B1 have been reported in 29 individuals from 22 families so far, most of which are homozygous mutations. Conclusions Our study enriched the genetic and phenotypic spectrum of SPG47. Early discovery, diagnosis and proper treatment on the conditions generally increase chances of improvement on the quality of life for patients.
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Affiliation(s)
- Wen-Cong Ruan
- Department of Rehabilitation, The Children's Hospital, Zhejiang University School of Medicine, Zhejiang, 310052, China
| | - Jia Wang
- Cipher Gene, LLC, Beijing, 100080, China
| | - Yong-Lin Yu
- Department of Rehabilitation, The Children's Hospital, Zhejiang University School of Medicine, Zhejiang, 310052, China
| | - Yue-Ping Che
- Department of Rehabilitation, The Children's Hospital, Zhejiang University School of Medicine, Zhejiang, 310052, China
| | - Li Ding
- Department of Rehabilitation, The Children's Hospital, Zhejiang University School of Medicine, Zhejiang, 310052, China
| | - Chen-Xi Li
- Department of Rehabilitation, The Children's Hospital, Zhejiang University School of Medicine, Zhejiang, 310052, China
| | | | - Hai-Feng Li
- Department of Rehabilitation, The Children's Hospital, Zhejiang University School of Medicine, Zhejiang, 310052, China.
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Szczałuba K, Mierzewska H, Śmigiel R, Kosińska J, Koppolu A, Biernacka A, Stawiński P, Pollak A, Rydzanicz M, Płoski R. AP4B1-associated hereditary spastic paraplegia: expansion of phenotypic spectrum related to homozygous p.Thr387fs variant. J Appl Genet 2020; 61:213-218. [PMID: 32166732 PMCID: PMC7148264 DOI: 10.1007/s13353-020-00552-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 02/05/2020] [Accepted: 02/12/2020] [Indexed: 11/11/2022]
Abstract
Biallelic mutations in the AP4B1 gene, encoding adaptor-related protein complex 4 beta-1 subunit, have been recognized as an important cause of a group of conditions leading to adaptor-related protein complex 4 (AP4)-associated hereditary spastic paraplegia (SPG47). We describe a homozygous, known variant c.1160_1161delCA (p.Thr387fs) that was found in the largest ever group of patients coming from four families. The patients exhibited early hypotonia progressing to spastic paraplegia, microcephaly, epilepsy, and central nervous system (CNS) defects and global developmental delay that are consistent with the nature of SPG47. Our findings expand phenotypic spectrum of SPG47 to include polymorphic seizures, mild/moderate intellectual disability, and intracerebral cysts as well as point to founder mutation in AP4 deficiency disorders in apparently non-consanguineous Polish families without shared ancestry.
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Affiliation(s)
- Krzysztof Szczałuba
- Department of Medical Genetics, Medical University of Warsaw, ul. Pawinskiego 3c, 02-106, Warsaw, Poland
| | - Hanna Mierzewska
- Department of Child and Adolescent Neurology, Institute of Mother and Child, Warsaw, Poland
| | - Robert Śmigiel
- Department of Paediatrics, Division of Paediatric Propaedeutics and Rare Disorders, Wroclawa Medical University, Wroclaw, Poland
| | - Joanna Kosińska
- Department of Medical Genetics, Medical University of Warsaw, ul. Pawinskiego 3c, 02-106, Warsaw, Poland
| | - Agnieszka Koppolu
- Department of Medical Genetics, Medical University of Warsaw, ul. Pawinskiego 3c, 02-106, Warsaw, Poland.,Postgraduate School of Molecular Medicine, Warsaw, Poland
| | - Anna Biernacka
- Department of Medical Genetics, Medical University of Warsaw, ul. Pawinskiego 3c, 02-106, Warsaw, Poland.,Postgraduate School of Molecular Medicine, Warsaw, Poland
| | - Piotr Stawiński
- Department of Medical Genetics, Medical University of Warsaw, ul. Pawinskiego 3c, 02-106, Warsaw, Poland.,Department of Genetics, Institute of Physiology and Pathology of Hearing, Warsaw, Poland
| | - Agnieszka Pollak
- Department of Medical Genetics, Medical University of Warsaw, ul. Pawinskiego 3c, 02-106, Warsaw, Poland
| | - Małgorzata Rydzanicz
- Department of Medical Genetics, Medical University of Warsaw, ul. Pawinskiego 3c, 02-106, Warsaw, Poland
| | - Rafał Płoski
- Department of Medical Genetics, Medical University of Warsaw, ul. Pawinskiego 3c, 02-106, Warsaw, Poland.
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Zatyka M, Sarkar S, Barrett T. Autophagy in Rare (NonLysosomal) Neurodegenerative Diseases. J Mol Biol 2020; 432:2735-2753. [PMID: 32087199 PMCID: PMC7232014 DOI: 10.1016/j.jmb.2020.02.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 02/10/2020] [Accepted: 02/10/2020] [Indexed: 12/13/2022]
Abstract
Neurodegenerative diseases (NDDs) comprise conditions with impaired neuronal function and loss and may be associated with a build-up of aggregated proteins with altered physicochemical properties (misfolded proteins). There are many disorders, and causes include gene mutations, infections, or exposure to toxins. The autophagy pathway is involved in the removal of unwanted proteins and organelles through lysosomes. While lysosomal storage disorders have been described for many years, it is now recognised that perturbations of the autophagy pathway itself can also lead to neurodegenerative disease. These include monogenic disorders of key proteins involved in the autophagy pathway, and disorders within pathways that critically control autophagy through monitoring of the supply of nutrients (mTORC1 pathway) or of energy supply in cells (AMPK pathway). This review focuses on childhood-onset neurodegenerative disorders with perturbed autophagy, due to defects in the autophagy pathway, or in upstream signalling via mTORC1 and AMPK. The review first provides a short description of autophagy, as related to neurons. It then examines the extended role of autophagy in neuronal function, plasticity, and memory. There follows a description of each step of the autophagy pathway in greater detail, illustrated with examples of diseases grouped by the stage of their perturbation of the pathway. Each disease is accompanied by a short clinical description, to illustrate the diversity but also the overlap of symptoms caused by perturbation of key proteins necessary for the proper functioning of autophagy. Finally, there is a consideration of current challenges that need addressing for future therapeutic advances. Autophagy is an important pathway for the removal of misfolded proteins from terminally differentiated neurons. Monogenic defects in autophagy cause childhood-onset neurodegeneration. Defects in different stages of the pathway may present with overlapping clinical features. Increasing autophagic flux may be a therapeutic strategy to treat many autophagic disorders.
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Affiliation(s)
- Malgorzata Zatyka
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Sovan Sarkar
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Timothy Barrett
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, UK; Department of Endocrinology, Birmingham Women's and Children's Hospital, Steelhouse Lane, Birmingham B4 6NH, UK.
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35
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Behne R, Teinert J, Wimmer M, D’Amore A, Davies AK, Scarrott JM, Eberhardt K, Brechmann B, Chen IPF, Buttermore ED, Barrett L, Dwyer S, Chen T, Hirst J, Wiesener A, Segal D, Martinuzzi A, Duarte ST, Bennett JT, Bourinaris T, Houlden H, Roubertie A, Santorelli FM, Robinson M, Azzouz M, Lipton JO, Borner GHH, Sahin M, Ebrahimi-Fakhari D. Adaptor protein complex 4 deficiency: a paradigm of childhood-onset hereditary spastic paraplegia caused by defective protein trafficking. Hum Mol Genet 2020; 29:320-334. [PMID: 31915823 PMCID: PMC7001721 DOI: 10.1093/hmg/ddz310] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 10/22/2019] [Accepted: 12/05/2019] [Indexed: 12/25/2022] Open
Abstract
Deficiency of the adaptor protein complex 4 (AP-4) leads to childhood-onset hereditary spastic paraplegia (AP-4-HSP): SPG47 (AP4B1), SPG50 (AP4M1), SPG51 (AP4E1) and SPG52 (AP4S1). This study aims to evaluate the impact of loss-of-function variants in AP-4 subunits on intracellular protein trafficking using patient-derived cells. We investigated 15 patient-derived fibroblast lines and generated six lines of induced pluripotent stem cell (iPSC)-derived neurons covering a wide range of AP-4 variants. All patient-derived fibroblasts showed reduced levels of the AP4E1 subunit, a surrogate for levels of the AP-4 complex. The autophagy protein ATG9A accumulated in the trans-Golgi network and was depleted from peripheral compartments. Western blot analysis demonstrated a 3-5-fold increase in ATG9A expression in patient lines. ATG9A was redistributed upon re-expression of AP4B1 arguing that mistrafficking of ATG9A is AP-4-dependent. Examining the downstream effects of ATG9A mislocalization, we found that autophagic flux was intact in patient-derived fibroblasts both under nutrient-rich conditions and when autophagy is stimulated. Mitochondrial metabolism and intracellular iron content remained unchanged. In iPSC-derived cortical neurons from patients with AP4B1-associated SPG47, AP-4 subunit levels were reduced while ATG9A accumulated in the trans-Golgi network. Levels of the autophagy marker LC3-II were reduced, suggesting a neuron-specific alteration in autophagosome turnover. Neurite outgrowth and branching were reduced in AP-4-HSP neurons pointing to a role of AP-4-mediated protein trafficking in neuronal development. Collectively, our results establish ATG9A mislocalization as a key marker of AP-4 deficiency in patient-derived cells, including the first human neuron model of AP-4-HSP, which will aid diagnostic and therapeutic studies.
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Affiliation(s)
- Robert Behne
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Department of Neurology, University Hospital Würzburg, 97080 Würzburg, Germany
| | - Julian Teinert
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Division of Pediatric Neurology and Metabolic Medicine, Center for Child and Adolescent Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Miriam Wimmer
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Angelica D’Amore
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Molecular Medicine, IRCCS Fondazione Stella Maris, 56018 Pisa, Italy
| | - Alexandra K Davies
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Joseph M Scarrott
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield S10 2HQ, UK
| | - Kathrin Eberhardt
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Barbara Brechmann
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Ivy Pin-Fang Chen
- Translational Neuroscience Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Elizabeth D Buttermore
- Translational Neuroscience Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Lee Barrett
- Translational Neuroscience Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Sean Dwyer
- Translational Neuroscience Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Teresa Chen
- Translational Neuroscience Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Jennifer Hirst
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Antje Wiesener
- Institute of Human Genetics, Friedrich-Alexander Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Devorah Segal
- Division of Pediatric Neurology, Department of Pediatrics, Weill Cornell Medicine, New York City, NY 10021, USA
| | - Andrea Martinuzzi
- Scientific Institute, IRCCS E. Medea, Unità Operativa Conegliano, 31015 Treviso, Italy
| | - Sofia T Duarte
- Department of Pediatric Neurology, Centro Hospitalar de Lisboa Central, 1169-050 Lisbon, Portugal
| | - James T Bennett
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, WA 98195, USA
| | - Thomas Bourinaris
- Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1E 6BT, UK
| | - Henry Houlden
- Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1E 6BT, UK
| | | | | | - Margaret Robinson
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Mimoun Azzouz
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Sheffield S10 2HQ, UK
| | - Jonathan O Lipton
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Division of Sleep Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Georg H H Borner
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Mustafa Sahin
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Translational Neuroscience Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Darius Ebrahimi-Fakhari
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, USA
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Teinert J, Behne R, Wimmer M, Ebrahimi-Fakhari D. Novel insights into the clinical and molecular spectrum of congenital disorders of autophagy. J Inherit Metab Dis 2020; 43:51-62. [PMID: 30854657 DOI: 10.1002/jimd.12084] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 03/07/2019] [Indexed: 12/24/2022]
Abstract
Autophagy is a fundamental and conserved catabolic pathway that mediates the degradation of macromolecules and organelles in lysosomes. Autophagy is particularly important to postmitotic and metabolically active cells such as neurons. The complex architecture of neurons and their long axons pose additional challenges for efficient recycling of cargo. Not surprisingly autophagy is required for normal central nervous system development and function. Several single-gene disorders of the autophagy pathway have been discovered in recent years giving rise to a novel group of inborn errors of metabolism referred to as congenital disorders of autophagy. While these disorders are heterogeneous, they share several clinical and molecular characteristics including a prominent and progressive involvement of the central nervous system leading to brain malformations, developmental delay, intellectual disability, epilepsy, movement disorders, and cognitive decline. On brain magnetic resonance imaging a predominant involvement of the corpus callosum, the corticospinal tracts and the cerebellum are noted. A storage disease phenotype is present in some diseases, underscoring both clinical and molecular overlaps to lysosomal storage diseases. This review provides an update on the clinical, imaging, and genetic spectrum of congenital disorders of autophagy and highlights the importance of this pathway for neurometabolism and childhood-onset neurological diseases.
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Affiliation(s)
- Julian Teinert
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Robert Behne
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Miriam Wimmer
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Darius Ebrahimi-Fakhari
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
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Sanger A, Hirst J, Davies AK, Robinson MS. Adaptor protein complexes and disease at a glance. J Cell Sci 2019; 132:132/20/jcs222992. [PMID: 31636158 DOI: 10.1242/jcs.222992] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Adaptor protein (AP) complexes are heterotetramers that select cargo for inclusion into transport vesicles. Five AP complexes (AP-1 to AP-5) have been described, each with a distinct localisation and function. Furthermore, patients with a range of disorders, particularly involving the nervous system, have now been identified with mutations in each of the AP complexes. In many cases this has been correlated with aberrantly localised membrane proteins. In this Cell Science at a Glance article and the accompanying poster, we summarize what is known about the five AP complexes and discuss how this helps to explain the clinical features of the different genetic disorders.
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Affiliation(s)
- Anneri Sanger
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Jennifer Hirst
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Alexandra K Davies
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Margaret S Robinson
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
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38
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Teinert J, Behne R, D'Amore A, Wimmer M, Dwyer S, Chen T, Buttermore ED, Chen IPF, Sahin M, Ebrahimi-Fakhari D. Generation and characterization of six human induced pluripotent stem cell lines (iPSC) from three families with AP4B1-associated hereditary spastic paraplegia (SPG47). Stem Cell Res 2019; 40:101575. [PMID: 31525725 PMCID: PMC7269118 DOI: 10.1016/j.scr.2019.101575] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 06/29/2019] [Accepted: 09/09/2019] [Indexed: 11/17/2022] Open
Abstract
Bi-allelic variants in the subunits of the adaptor protein complex 4 lead to childhood-onset, complex hereditary spastic paraplegia (AP-4-HSP): SPG47 (AP4B1), SPG50 (AP4M1), SPG51 (AP4E1), and SPG52 (AP4S1). Here, we describe the generation of induced pluripotent stem cells (iPSCs) from three AP-4-HSP patients with compound-heterozygous, loss-of-function variants in AP4B1 and sex-matched parents. Fibroblasts were reprogrammed using non-integrating Sendai virus. iPSCs were characterized according to standard protocols including karyotyping, embryoid body formation, pluripotency marker expression and STR profiling. These first iPSC lines for SPG47 provide a valuable resource for studying this rare disease and related forms of hereditary spastic paraplegia.
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Affiliation(s)
- Julian Teinert
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Robert Behne
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Angelica D'Amore
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Miriam Wimmer
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Sean Dwyer
- Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Teresa Chen
- Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Elizabeth D Buttermore
- Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Ivy Pin-Fang Chen
- Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Mustafa Sahin
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Translational Neuroscience Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Darius Ebrahimi-Fakhari
- Department of Neurology, The F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
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39
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40
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Zhu Y, Runwal G, Obrocki P, Rubinsztein DC. Autophagy in childhood neurological disorders. Dev Med Child Neurol 2019; 61:639-645. [PMID: 30417343 DOI: 10.1111/dmcn.14092] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/21/2018] [Indexed: 01/16/2023]
Abstract
Autophagy is a tightly modulated lysosomal degradation pathway. Genetic disorders of autophagy during nervous system development may lead to developmental delay, neurodegeneration, and other neurological signs in children. Here we aimed to summarize single gene disorders that perturb various steps of autophagy pathway and their roles in the causation of childhood neurological diseases. Numerous childhood-onset disorders are caused by mutations that impact the autophagy pathway. These can manifest with a range of features including ataxia, spastic paraplegia, and intellectual disability. Defective proteins causing such diseases can interfere with autophagy flux at different stages of the itinerary. Defective autophagy may be an important contributor to the pathological features of various childhood neurodegenerative diseases and lead to the accumulation of aberrant protein and dysfunctional organelles. Insights into the relevant cell biological processes may help understand pathophysiological mechanisms and inspire autophagy-restoring therapeutic approaches. WHAT THIS PAPER ADDS: Numerous childhood-onset disorders are caused by mutations that impact the autophagy pathway. Defective autophagy is a feature of some mutations that cause ataxia, spastic paraplegia, and intellectual disability.
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Affiliation(s)
- Ye Zhu
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge, UK
| | - Gautam Runwal
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge, UK
| | - Pawel Obrocki
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge, UK
| | - David C Rubinsztein
- Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge, UK.,UK Dementia Research Institute, Wellcome Trust, Cambridge Biomedical Campus, Cambridge, UK
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Hebbar M, Shukla A, Nampoothiri S, Bielas S, Girisha KM. Locus and allelic heterogeneity in five families with hereditary spastic paraplegia. J Hum Genet 2018; 64:17-21. [PMID: 30337681 PMCID: PMC6344291 DOI: 10.1038/s10038-018-0523-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 09/12/2018] [Accepted: 10/08/2018] [Indexed: 01/29/2023]
Abstract
Hereditary spastic paraplegias are a group of genetically heterogeneous neurological disorders characterized by progressive weakness and spasticity of lower limbs. We ascertained five families with eight individuals with hereditary spastic paraplegia. Pathogenic variants were identified by exome sequencing of index cases. The cohort consists of three families with spastic paraplegia type 47 (AP4B1) with a common mutation in two families, a family with spastic paraplegia type 50 (AP4M1), and two male siblings with X-linked spastic paraplegia 2 (PLP1). This work illustrates locus and allelic heterogeneity in five families with hereditary spastic paraplegia.
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Affiliation(s)
- Malavika Hebbar
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Anju Shukla
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India
| | - Sheela Nampoothiri
- Department of Pediatric Genetics, Amrita Institute of Medical Sciences and Research Centre, Ponekkara, Cochin, Kerala, India
| | - Stephanie Bielas
- Department of Human Genetics, University of Michigan, Ann Arbor, MI, USA
| | - Katta M Girisha
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, India.
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Davies AK, Itzhak DN, Edgar JR, Archuleta TL, Hirst J, Jackson LP, Robinson MS, Borner GHH. AP-4 vesicles contribute to spatial control of autophagy via RUSC-dependent peripheral delivery of ATG9A. Nat Commun 2018; 9:3958. [PMID: 30262884 PMCID: PMC6160451 DOI: 10.1038/s41467-018-06172-7] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 08/17/2018] [Indexed: 12/03/2022] Open
Abstract
Adaptor protein 4 (AP-4) is an ancient membrane trafficking complex, whose function has largely remained elusive. In humans, AP-4 deficiency causes a severe neurological disorder of unknown aetiology. We apply unbiased proteomic methods, including 'Dynamic Organellar Maps', to find proteins whose subcellular localisation depends on AP-4. We identify three transmembrane cargo proteins, ATG9A, SERINC1 and SERINC3, and two AP-4 accessory proteins, RUSC1 and RUSC2. We demonstrate that AP-4 deficiency causes missorting of ATG9A in diverse cell types, including patient-derived cells, as well as dysregulation of autophagy. RUSC2 facilitates the transport of AP-4-derived, ATG9A-positive vesicles from the trans-Golgi network to the cell periphery. These vesicles cluster in close association with autophagosomes, suggesting they are the "ATG9A reservoir" required for autophagosome biogenesis. Our study uncovers ATG9A trafficking as a ubiquitous function of the AP-4 pathway. Furthermore, it provides a potential molecular pathomechanism of AP-4 deficiency, through dysregulated spatial control of autophagy.
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Affiliation(s)
- Alexandra K Davies
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
| | - Daniel N Itzhak
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, 82152, Germany
| | - James R Edgar
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
| | - Tara L Archuleta
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, 37235, USA
| | - Jennifer Hirst
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
| | - Lauren P Jackson
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, 37235, USA
| | - Margaret S Robinson
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK.
| | - Georg H H Borner
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Martinsried, 82152, Germany.
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Altered distribution of ATG9A and accumulation of axonal aggregates in neurons from a mouse model of AP-4 deficiency syndrome. PLoS Genet 2018; 14:e1007363. [PMID: 29698489 PMCID: PMC5940238 DOI: 10.1371/journal.pgen.1007363] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 05/08/2018] [Accepted: 04/12/2018] [Indexed: 12/22/2022] Open
Abstract
The hereditary spastic paraplegias (HSP) are a clinically and genetically heterogeneous group of disorders characterized by progressive lower limb spasticity. Mutations in subunits of the heterotetrameric (ε-β4-μ4-σ4) adaptor protein 4 (AP-4) complex cause an autosomal recessive form of complicated HSP referred to as "AP-4 deficiency syndrome". In addition to lower limb spasticity, this syndrome features intellectual disability, microcephaly, seizures, thin corpus callosum and upper limb spasticity. The pathogenetic mechanism, however, remains poorly understood. Here we report the characterization of a knockout (KO) mouse for the AP4E1 gene encoding the ε subunit of AP-4. We find that AP-4 ε KO mice exhibit a range of neurological phenotypes, including hindlimb clasping, decreased motor coordination and weak grip strength. In addition, AP-4 ε KO mice display a thin corpus callosum and axonal swellings in various areas of the brain and spinal cord. Immunohistochemical analyses show that the transmembrane autophagy-related protein 9A (ATG9A) is more concentrated in the trans-Golgi network (TGN) and depleted from the peripheral cytoplasm both in skin fibroblasts from patients with mutations in the μ4 subunit of AP-4 and in various neuronal types in AP-4 ε KO mice. ATG9A mislocalization is associated with increased tendency to accumulate mutant huntingtin (HTT) aggregates in the axons of AP-4 ε KO neurons. These findings indicate that the AP-4 ε KO mouse is a suitable animal model for AP-4 deficiency syndrome, and that defective mobilization of ATG9A from the TGN and impaired autophagic degradation of protein aggregates might contribute to neuroaxonal dystrophy in this disorder.
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