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Liang J, Djurkovic MA, Shtanko O, Harty RN. Chaperoning the driver of filovirus egress to a dead end. Autophagy 2023; 19:2809-2810. [PMID: 36763514 PMCID: PMC10472846 DOI: 10.1080/15548627.2023.2178781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/03/2023] [Accepted: 02/06/2023] [Indexed: 02/11/2023] Open
Abstract
Ebola virus (EBOV) and Marburg virus (MARV) are zoonotic, virulent pathogens that cause sporadic and global outbreaks of severe hemorrhagic fever. Reemergence of these filoviruses remains a global public health threat, highlighting the need for novel countermeasures to control and treat future disease outbreaks. The EBOV VP40 matrix protein drives virion assembly and egress. We recently reported that BAG3 and HSPA/HSP70, two central components of chaperone-assisted selective autophagy (CASA), target VP40 for autophagic sequestration and degradation, thereby inhibiting virus egress and spread. In addition, we found that expression of the EBOV glycoprotein (GP) activates MTORC1, the gateway regulator of autophagy. Notably, pharmacological suppression of MTORC1 signaling by rapamycin activates autophagy and blocks filovirus egress. These findings highlight the MTORC1-CASA axis as a regulator of filovirus egress and suggest new opportunities for antiviral development and intervention.
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Affiliation(s)
- Jingjing Liang
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Marija A. Djurkovic
- Host-Pathogen Interactions, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Olena Shtanko
- Host-Pathogen Interactions, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Ronald N. Harty
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
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2
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Winter L, Staszewska-Daca I, Zittrich S, Elhamine F, Zrelski MM, Schmidt K, Fischer I, Jüngst C, Schauss A, Goldmann WH, Stehle R, Wiche G. Z-Disk-Associated Plectin (Isoform 1d): Spatial Arrangement, Interaction Partners, and Role in Filamin C Homeostasis. Cells 2023; 12:1259. [PMID: 37174658 PMCID: PMC10177080 DOI: 10.3390/cells12091259] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 04/15/2023] [Accepted: 04/25/2023] [Indexed: 05/15/2023] Open
Abstract
Plectin, a highly versatile cytolinker protein, is crucial for myofiber integrity and function. Accordingly, mutations in the human gene (PLEC) cause several rare diseases, denoted as plectinopathies, with most of them associated with progressive muscle weakness. Of several plectin isoforms expressed in skeletal muscle and the heart, P1d is the only isoform expressed exclusively in these tissues. Using high-resolution stimulated emission depletion (STED) microscopy, here we show that plectin is located within the gaps between individual α-actinin-positive Z-disks, recruiting and bridging them to desmin intermediate filaments (Ifs). Loss of plectin in myofibril bundles led to a complete loss of desmin Ifs. Loss of Z-disk-associated plectin isoform P1d led to disorganization of muscle fibers and slower relaxation of myofibrils upon mechanical strain, in line with an observed inhomogeneity of muscle ultrastructure. In addition to binding to α-actinin and thereby providing structural support, P1d forms a scaffolding platform for the chaperone-assisted selective autophagy machinery (CASA) by directly interacting with HSC70 and synpo2. In isoform-specific knockout (P1d-KO) mouse muscle and mechanically stretched plectin-deficient myoblasts, we found high levels of undigested filamin C, a bona fide substrate of CASA. Similarly, subjecting P1d-KO mice to forced swim tests led to accumulation of filamin C aggregates in myofibers, highlighting a specific role of P1d in tension-induced proteolysis activated upon high loads of physical exercise and muscle contraction.
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Affiliation(s)
- Lilli Winter
- Department of Biochemistry and Cell Biology, Max Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
- Division of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, 1090 Vienna, Austria
| | - Ilona Staszewska-Daca
- Department of Biochemistry and Cell Biology, Max Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
| | - Stefan Zittrich
- Institute of Vegetative Physiology, Medical Faculty, University of Cologne, 50931 Cologne, Germany
| | - Fatiha Elhamine
- Institute of Vegetative Physiology, Medical Faculty, University of Cologne, 50931 Cologne, Germany
| | - Michaela M. Zrelski
- Division of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, 1090 Vienna, Austria
| | - Katy Schmidt
- Division of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, 1090 Vienna, Austria
- Core Facility for Cell Imaging & Ultrastructure Research (CIUS), University of Vienna, 1030 Vienna, Austria
| | - Irmgard Fischer
- Department of Biochemistry and Cell Biology, Max Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
| | - Christian Jüngst
- CECAD Imaging Facility, CECAD Forschungszentrum Cologne, 50931 Cologne, Germany
| | - Astrid Schauss
- CECAD Imaging Facility, CECAD Forschungszentrum Cologne, 50931 Cologne, Germany
| | - Wolfgang H. Goldmann
- Department of Physics, Center for Medical Physics and Technology, Friedrich-Alexander-University Erlangen-Nuremberg, 91052 Erlangen, Germany
| | - Robert Stehle
- Institute of Vegetative Physiology, Medical Faculty, University of Cologne, 50931 Cologne, Germany
| | - Gerhard Wiche
- Department of Biochemistry and Cell Biology, Max Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
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Tedesco B, Ferrari V, Cozzi M, Chierichetti M, Casarotto E, Pramaggiore P, Mina F, Piccolella M, Cristofani R, Crippa V, Rusmini P, Galbiati M, Poletti A. The role of autophagy-lysosomal pathway in motor neuron diseases. Biochem Soc Trans 2022; 50:1489-1503. [PMID: 36111809 PMCID: PMC9704526 DOI: 10.1042/bst20220778] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 08/20/2022] [Accepted: 08/22/2022] [Indexed: 10/22/2023]
Abstract
Motor neuron diseases (MNDs) include a broad group of diseases in which neurodegeneration mainly affects upper and/or lower motor neurons (MNs). Although the involvement of specific MNs, symptoms, age of onset, and progression differ in MNDs, the main pathogenic mechanism common to most MNDs is represented by proteostasis alteration and proteotoxicity. This pathomechanism may be directly related to mutations in genes encoding proteins involved in the protein quality control system, particularly the autophagy-lysosomal pathway (ALP). Alternatively, proteostasis alteration can be caused by aberrant proteins that tend to misfold and to aggregate, two related processes that, over time, cannot be properly handled by the ALP. Here, we summarize the main ALP features, focusing on different routes utilized to deliver substrates to the lysosome and how the various ALP pathways intersect with the intracellular trafficking of membranes and vesicles. Next, we provide an overview of the mutated genes that have been found associated with MNDs, how these gene products are involved in different steps of ALP and related processes. Finally, we discuss how autophagy can be considered a valid therapeutic target for MNDs treatment focusing on traditional autophagy modulators and on emerging approaches to overcome their limitations.
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Affiliation(s)
- Barbara Tedesco
- Dipartimento di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università degli Studi di Milano, Milano, Italy
- Unit of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Veronica Ferrari
- Dipartimento di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università degli Studi di Milano, Milano, Italy
| | - Marta Cozzi
- Dipartimento di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università degli Studi di Milano, Milano, Italy
| | - Marta Chierichetti
- Dipartimento di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università degli Studi di Milano, Milano, Italy
| | - Elena Casarotto
- Dipartimento di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università degli Studi di Milano, Milano, Italy
| | - Paola Pramaggiore
- Dipartimento di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università degli Studi di Milano, Milano, Italy
| | - Francesco Mina
- Dipartimento di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università degli Studi di Milano, Milano, Italy
| | - Margherita Piccolella
- Dipartimento di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università degli Studi di Milano, Milano, Italy
| | - Riccardo Cristofani
- Dipartimento di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università degli Studi di Milano, Milano, Italy
| | - Valeria Crippa
- Dipartimento di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università degli Studi di Milano, Milano, Italy
| | - Paola Rusmini
- Dipartimento di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università degli Studi di Milano, Milano, Italy
| | - Mariarita Galbiati
- Dipartimento di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università degli Studi di Milano, Milano, Italy
| | - Angelo Poletti
- Dipartimento di Scienze Farmacologiche e Biomolecolari (DiSFeB), Università degli Studi di Milano, Milano, Italy
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Abstract
Autophagy is an evolutionarily conserved catabolic process that targets different types of cytoplasmic cargo (such as bulk cytoplasm, damaged cellular organelles, and misfolded protein aggregates) for lysosomal degradation. Autophagy is activated in response to biological stress and also plays a critical role in the maintenance of normal cellular homeostasis; the latter function is particularly important for the integrity of postmitotic, metabolically active tissues, such as skeletal muscle. Through impairment of muscle homeostasis, autophagy dysfunction contributes to the pathogenesis of many different skeletal myopathies; the observed autophagy defects differ from disease to disease but have been shown to involve all steps of the autophagic cascade (from induction to lysosomal cargo degradation) and to impair both bulk and selective autophagy. To highlight the molecular and cellular mechanisms that are shared among different myopathies with deficient autophagy, these disorders are discussed based on the nature of the underlying autophagic defect rather than etiology or clinical presentation.
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Affiliation(s)
- Marta Margeta
- Department of Pathology, University of California, San Francisco, California 94143, USA;
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Du A, Huang S, Zhao X, Feng K, Zhang S, Huang J, Miao X, Baggi F, Ostrom RS, Zhang Y, Chen X, Xu C. Suppression of CHRN endocytosis by carbonic anhydrase CAR3 in the pathogenesis of myasthenia gravis. Autophagy 2017; 13:1981-1994. [PMID: 28933591 PMCID: PMC5788490 DOI: 10.1080/15548627.2017.1375633] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Myasthenia gravis is an autoimmune disorder of the neuromuscular junction manifested as fatigable muscle weakness, which is typically caused by pathogenic autoantibodies against postsynaptic CHRN/AChR (cholinergic receptor nicotinic) in the endplate of skeletal muscle. Our previous studies have identified CA3 (carbonic anhydrase 3) as a specific protein insufficient in skeletal muscle from myasthenia gravis patients. In this study, we investigated the underlying mechanism of how CA3 insufficiency might contribute to myasthenia gravis. Using an experimental autoimmune myasthenia gravis animal model and the skeletal muscle cell C2C12, we find that inhibition of CAR3 (the mouse homolog of CA3) promotes CHRN internalization via a lipid raft-mediated pathway, leading to accelerated degradation of postsynaptic CHRN. Activation of CAR3 reduces CHRN degradation by suppressing receptor endocytosis. CAR3 exerts this effect by suppressing chaperone-assisted selective autophagy via interaction with BAG3 (BCL2-associated athanogene 3) and by dampening endoplasmic reticulum stress. Collectively, our study illustrates that skeletal muscle cell CAR3 is critical for CHRN homeostasis in the neuromuscular junction, and its deficiency leads to accelerated degradation of CHRN and development of myasthenia gravis, potentially revealing a novel therapeutic approach for this disorder.
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Affiliation(s)
- Ailian Du
- a Department of Neurology, Tongren Hospital , Shanghai Jiao Tong University School of Medicine (SJTUSM) , Shanghai , China
| | - Shiqian Huang
- b Shanghai Institute of Immunology, Institutes of Medical Sciences , Shanghai Jiao Tong University School of Medicine , Shanghai , China
| | - Xiaonan Zhao
- b Shanghai Institute of Immunology, Institutes of Medical Sciences , Shanghai Jiao Tong University School of Medicine , Shanghai , China
| | - Kuan Feng
- c Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences & SJTUSM , Shanghai , China
| | - Shuangyan Zhang
- b Shanghai Institute of Immunology, Institutes of Medical Sciences , Shanghai Jiao Tong University School of Medicine , Shanghai , China
| | - Jiefang Huang
- c Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences & SJTUSM , Shanghai , China
| | - Xiang Miao
- c Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences & SJTUSM , Shanghai , China
| | - Fulvio Baggi
- d Neurology IV-Neuroimmunology and Neuromuscular Diseases Unit, Fondazione Istituto Neurologico "Carlo Besta" , Milan , Italy
| | - Rennolds S Ostrom
- e Department of Biomedical and Pharmaceutical Sciences , Chapman University School of Pharmacy , Irvine , CA , USA
| | - Yanyun Zhang
- b Shanghai Institute of Immunology, Institutes of Medical Sciences , Shanghai Jiao Tong University School of Medicine , Shanghai , China.,c Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences & SJTUSM , Shanghai , China
| | - Xiangjun Chen
- f Department of Neurology , Fudan University Huashan Hospital, and Institute of Neurology, Fudan University , Shanghai , China
| | - Congfeng Xu
- b Shanghai Institute of Immunology, Institutes of Medical Sciences , Shanghai Jiao Tong University School of Medicine , Shanghai , China.,c Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences & SJTUSM , Shanghai , China
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