51
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Han S, Jeong YY, Sheshadri P, Su X, Cai Q. Mitophagy regulates integrity of mitochondria at synapses and is critical for synaptic maintenance. EMBO Rep 2020; 21:e49801. [PMID: 32627320 DOI: 10.15252/embr.201949801] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 06/01/2020] [Accepted: 06/05/2020] [Indexed: 01/25/2023] Open
Abstract
Synaptic mitochondria are particularly vulnerable to physiological insults, and defects in synaptic mitochondria are linked to early pathophysiology of Alzheimer's disease (AD). Mitophagy, a cargo-specific autophagy for elimination of dysfunctional mitochondria, constitutes a key quality control mechanism. However, how mitophagy ensures synaptic mitochondrial integrity remains largely unknown. Here, we reveal Rheb and Snapin as key players regulating mitochondrial homeostasis at synapses. Rheb initiates mitophagy to target damaged mitochondria for autophagy, whereas dynein-Snapin-mediated retrograde transport promotes clearance of mitophagosomes from synaptic terminals. We demonstrate that synaptic accumulation of mitophagosomes is a feature in AD-related mutant hAPP mouse brains, which is attributed to increased mitophagy initiation coupled with impaired removal of mitophagosomes from AD synapses due to defective retrograde transport. Furthermore, while deficiency in dynein-Snapin-mediated retrograde transport recapitulates synaptic mitophagy stress and induces synaptic degeneration, elevated Snapin expression attenuates mitochondrial defects and ameliorates synapse loss in AD mouse brains. Taken together, our study provides new insights into mitophagy regulation of synaptic mitochondrial integrity, establishing a foundation for mitigating AD-associated mitochondria deficits and synaptic damage through mitophagy enhancement.
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Affiliation(s)
- Sinsuk Han
- Division of Life Science, Department of Cell Biology and Neuroscience, School of Arts and Sciences, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Yu Young Jeong
- Division of Life Science, Department of Cell Biology and Neuroscience, School of Arts and Sciences, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Preethi Sheshadri
- Division of Life Science, Department of Cell Biology and Neuroscience, School of Arts and Sciences, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Xiao Su
- Division of Life Science, Department of Cell Biology and Neuroscience, School of Arts and Sciences, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Qian Cai
- Division of Life Science, Department of Cell Biology and Neuroscience, School of Arts and Sciences, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
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52
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Limanaqi F, Busceti CL, Biagioni F, Cantini F, Lenzi P, Fornai F. Cell-Clearing Systems Bridging Repeat Expansion Proteotoxicity and Neuromuscular Junction Alterations in ALS and SBMA. Int J Mol Sci 2020; 21:ijms21114021. [PMID: 32512809 PMCID: PMC7312203 DOI: 10.3390/ijms21114021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 05/29/2020] [Accepted: 06/03/2020] [Indexed: 12/12/2022] Open
Abstract
The coordinated activities of autophagy and the ubiquitin proteasome system (UPS) are key to preventing the aggregation and toxicity of misfold-prone proteins which manifest in a number of neurodegenerative disorders. These include proteins which are encoded by genes containing nucleotide repeat expansions. In the present review we focus on the overlapping role of autophagy and the UPS in repeat expansion proteotoxicity associated with chromosome 9 open reading frame 72 (C9ORF72) and androgen receptor (AR) genes, which are implicated in two motor neuron disorders, amyotrophic lateral sclerosis (ALS) and spinal-bulbar muscular atrophy (SBMA), respectively. At baseline, both C9ORF72 and AR regulate autophagy, while their aberrantly-expanded isoforms may lead to a failure in both autophagy and the UPS, further promoting protein aggregation and toxicity within motor neurons and skeletal muscles. Besides proteotoxicity, autophagy and UPS alterations are also implicated in neuromuscular junction (NMJ) alterations, which occur early in both ALS and SBMA. In fact, autophagy and the UPS intermingle with endocytic/secretory pathways to regulate axonal homeostasis and neurotransmission by interacting with key proteins which operate at the NMJ, such as agrin, acetylcholine receptors (AChRs), and adrenergic beta2 receptors (B2-ARs). Thus, alterations of autophagy and the UPS configure as a common hallmark in both ALS and SBMA disease progression. The findings here discussed may contribute to disclosing overlapping molecular mechanisms which are associated with a failure in cell-clearing systems in ALS and SBMA.
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Affiliation(s)
- Fiona Limanaqi
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 55, 56126 Pisa, Italy; (F.L.); (F.C.); (P.L.)
| | | | - Francesca Biagioni
- I.R.C.C.S. Neuromed, Via Atinense, 18, 86077 Pozzilli, Italy; (C.L.B.); (F.B.)
| | - Federica Cantini
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 55, 56126 Pisa, Italy; (F.L.); (F.C.); (P.L.)
| | - Paola Lenzi
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 55, 56126 Pisa, Italy; (F.L.); (F.C.); (P.L.)
| | - Francesco Fornai
- Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Roma 55, 56126 Pisa, Italy; (F.L.); (F.C.); (P.L.)
- I.R.C.C.S. Neuromed, Via Atinense, 18, 86077 Pozzilli, Italy; (C.L.B.); (F.B.)
- Correspondence:
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Liang C, Shao Q, Zhang W, Yang M, Chang Q, Chen R, Chen JF. Smcr8 deficiency disrupts axonal transport-dependent lysosomal function and promotes axonal swellings and gain of toxicity in C9ALS/FTD mouse models. Hum Mol Genet 2020; 28:3940-3953. [PMID: 31625563 DOI: 10.1093/hmg/ddz230] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 08/28/2019] [Accepted: 09/23/2019] [Indexed: 02/06/2023] Open
Abstract
G4C2 repeat expansions in an intron of C9ORF72 cause the most common familial amyotrophic lateral sclerosis and frontotemporal dementia (collectively, C9ALS/FTD). Mechanisms and mediators of C9ALS/FTD pathogenesis remain poorly understood. C9orf72 and Smcr8 form a protein complex. Here, we show that expression of Smcr8, like C9orf72, is reduced in C9ALS/FTD mouse models and patient tissues. Since Smcr8 is highly conserved between human and mouse, we evaluated the effects of Smcr8 downregulation in mice. Smcr8 knockout (KO) mice exhibited motor behavior deficits, which resemble those of C9ALS/FTD mouse models, and displayed axonal swellings in their spinal cords and neuromuscular junctions. These deficits are caused by impaired autophagy-lysosomal functions due to disrupted axonal transport in mutant motor neurons. Consistent with its interaction with C9orf72 and their downregulation in patient tissues, Smcr8 deficiency exacerbated autophagy-lysosomal impairment in C9orf72 KO mice. The disease relevance of Smcr8 downregulation was reflected by exacerbated axonal swellings and gain of toxicity pathology arising from Smcr8 haploinsufficiency in a mouse model of C9ALS/FTD. Thus, our in vivo studies suggested that Smcr8 deficiency impairs axonal transport dependent autophagy-lysosomal function and exacerbates axonal degeneration and gain of toxicity in C9ALS/FTD mouse models.
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Affiliation(s)
- Chen Liang
- Center for Craniofacial Molecular Biology, University of Southern California (USC), Los Angeles, CA 90033, USA.,Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
| | - Qiang Shao
- Center for Craniofacial Molecular Biology, University of Southern California (USC), Los Angeles, CA 90033, USA
| | - Wei Zhang
- Center for Craniofacial Molecular Biology, University of Southern California (USC), Los Angeles, CA 90033, USA
| | - Mei Yang
- Center for Craniofacial Molecular Biology, University of Southern California (USC), Los Angeles, CA 90033, USA
| | - Qing Chang
- Center for Craniofacial Molecular Biology, University of Southern California (USC), Los Angeles, CA 90033, USA
| | - Rong Chen
- Department of Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, 100 N. Greene Street, Baltimore, MD 21205, USA
| | - Jian-Fu Chen
- Center for Craniofacial Molecular Biology, University of Southern California (USC), Los Angeles, CA 90033, USA
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Tomoda T, Yang K, Sawa A. Neuronal Autophagy in Synaptic Functions and Psychiatric Disorders. Biol Psychiatry 2020; 87:787-796. [PMID: 31542152 PMCID: PMC6986983 DOI: 10.1016/j.biopsych.2019.07.018] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 07/02/2019] [Accepted: 07/19/2019] [Indexed: 12/22/2022]
Abstract
Homeostatic maintenance of physiological functions is fundamental to organismal well-being. Disruption or imbalance in homeostasis results in functional disturbances at molecular, cellular, and tissue levels, leading to manifestation as physical and mental illnesses. Homeostatic imbalance is caused by a range of pathophysiological mechanisms, including disrupted reduction-oxidation reactions, inflammatory responses, metabolic disturbances, or failure in quality control of cellular proteins and organelles. However, the roles for the protein/organelle quality control in the regulation of behaviors, in particular of cognitive processes, had not been well documented, until recent reports finally supported this concept. The frontline studies in neuroscience have revealed that synaptic components (e.g., synaptic proteins, organelles, neurotransmitters and their receptors) are selectively degraded by autophagy, a cellular recycling machinery implicated in surveillance and quality control of proteins and organelles responsible for the maintenance of cellular homeostasis. Apart from the canonical role of autophagy in supporting cell viability, synaptic autophagy appears to regulate synapse remodeling and plasticity. Consistently, emerging evidence suggests novel roles of autophagy in memory encoding, information processing, or cognitive functions. In this review, we overview recent progress in understanding the roles of neuronal autophagy in homeostatic maintenance of synaptic functions, with particular focus on how disruptions in these processes may contribute to the pathophysiology of psychiatric disorders.
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Affiliation(s)
- Toshifumi Tomoda
- Centre for Addiction and Mental Health, University of Toronto, Toronto, Ontario, Canada.
| | - Kun Yang
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Akira Sawa
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, Maryland; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland; Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland; Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland; Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.
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Autophagy in motor neuron diseases. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 172:157-202. [PMID: 32620242 DOI: 10.1016/bs.pmbts.2020.03.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Motor neuron diseases (MNDs) are a wide group of neurodegenerative disorders characterized by the degeneration of a specific neuronal type located in the central nervous system, the motor neuron (MN). There are two main types of MNs, spinal and cortical MNs and depending on the type of MND, one or both types are affected. Cortical MNs innervate spinal MNs and these control a variety of cellular targets, being skeletal muscle their main one which is also affected in MNDs. A correct functionality of autophagy is necessary for the survival of all cellular types and it is particularly crucial for neurons, given their postmitotic and highly specialized nature. Numerous studies have identified alterations of autophagy activity in multiple MNDs. The scientific community has been particularly prolific in reporting the role that autophagy plays in the most common adult MND, amyotrophic lateral sclerosis, although many studies have started to identify physiological and pathological functions of this catabolic system in other MNDs, such as spinal muscular atrophy and spinal and bulbar muscular atrophy. The degradation of selective cargo by autophagy and how this process is altered upon the presence of MND-causing mutations is currently also a matter of intense investigation, particularly regarding the selective autophagic clearance of mitochondria. Thorough reviews on this field have been recently published. This chapter will cover the current knowledge on the functionality of autophagy and lysosomal homeostasis in the main MNDs and other autophagy-related topics in the MND field that have risen special interest in the research community.
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Suzuki N, Akiyama T, Warita H, Aoki M. Omics Approach to Axonal Dysfunction of Motor Neurons in Amyotrophic Lateral Sclerosis (ALS). Front Neurosci 2020; 14:194. [PMID: 32269505 PMCID: PMC7109447 DOI: 10.3389/fnins.2020.00194] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 02/24/2020] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is an intractable adult-onset neurodegenerative disease that leads to the loss of upper and lower motor neurons (MNs). The long axons of MNs become damaged during the early stages of ALS. Genetic and pathological analyses of ALS patients have revealed dysfunction in the MN axon homeostasis. However, the molecular pathomechanism for the degeneration of axons in ALS has not been fully elucidated. This review provides an overview of the proposed axonal pathomechanisms in ALS, including those involving the neuronal cytoskeleton, cargo transport within axons, axonal energy supply, clearance of junk protein, neuromuscular junctions (NMJs), and aberrant axonal branching. To improve understanding of the global changes in axons, the review summarizes omics analyses of the axonal compartments of neurons in vitro and in vivo, including a motor nerve organoid approach that utilizes microfluidic devices developed by this research group. The review also discusses the relevance of intra-axonal transcription factors frequently identified in these omics analyses. Local axonal translation and the relationship among these pathomechanisms should be pursued further. The development of novel strategies to analyze axon fractions provides a new approach to establishing a detailed understanding of resilience of long MN and MN pathology in ALS.
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Affiliation(s)
- Naoki Suzuki
- Department of Neurology, Tohoku University School of Medicine, Sendai, Japan.,Department of Neurology, Shodo-kai Southern Tohoku General Hospital, Miyagi, Japan
| | - Tetsuya Akiyama
- Department of Neurology, Tohoku University School of Medicine, Sendai, Japan
| | - Hitoshi Warita
- Department of Neurology, Tohoku University School of Medicine, Sendai, Japan
| | - Masashi Aoki
- Department of Neurology, Tohoku University School of Medicine, Sendai, Japan
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57
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Darios F, Stevanin G. Impairment of Lysosome Function and Autophagy in Rare Neurodegenerative Diseases. J Mol Biol 2020; 432:2714-2734. [PMID: 32145221 PMCID: PMC7232018 DOI: 10.1016/j.jmb.2020.02.033] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 02/28/2020] [Accepted: 02/28/2020] [Indexed: 02/07/2023]
Abstract
Rare genetic diseases affect a limited number of patients, but their etiology is often known, facilitating the development of reliable animal models and giving the opportunity to investigate physiopathology. Lysosomal storage disorders are a group of rare diseases due to primary alteration of lysosome function. These diseases are often associated with neurological symptoms, which highlighted the importance of lysosome in neurodegeneration. Likewise, other groups of rare neurodegenerative diseases also present lysosomal alteration. Lysosomes fuse with autophagosomes and endosomes to allow the degradation of their content thanks to hydrolytic enzymes. It has emerged that alteration of the autophagy–lysosome pathway could play a critical role in neuronal death in many neurodegenerative diseases. Using a repertoire of selected rare neurodegenerative diseases, we highlight that a variety of alterations of the autophagy–lysosome pathway are associated with neuronal death. Yet, in most cases, it is still unclear why alteration of this pathway can lead to neurodegeneration. Lysosome function is impaired in many rare neurodegenerative diseases, making it a convergent point for these diseases. Impaired lysosome function is associated with alteration of the autophagy pathway. Autophagy–lysosome pathway can be impaired at various steps in different rare neurodegenerative diseases. The mechanisms linking impaired autophagy–lysosome pathway to neurodegeneration are still not fully elucidated.
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Affiliation(s)
- Frédéric Darios
- Sorbonne Université, F-75013, Paris, France; Inserm, U1127, F-75013 Paris, France; CNRS, UMR 7225, F-75013 Paris, France; Institut du Cerveau et de la Moelle Epinière, ICM, F-75013 Paris, France.
| | - Giovanni Stevanin
- Sorbonne Université, F-75013, Paris, France; Inserm, U1127, F-75013 Paris, France; CNRS, UMR 7225, F-75013 Paris, France; Institut du Cerveau et de la Moelle Epinière, ICM, F-75013 Paris, France; PSL Research University, Ecole Pratique des Hautes Etudes, Laboratoire de Neurogénétique, F-75013 Paris, France
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58
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Strohm L, Behrends C. Glia-specific autophagy dysfunction in ALS. Semin Cell Dev Biol 2020; 99:172-182. [DOI: 10.1016/j.semcdb.2019.05.024] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 04/30/2019] [Accepted: 05/23/2019] [Indexed: 12/12/2022]
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59
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Ivankovic D, Drew J, Lesept F, White IJ, López Doménech G, Tooze SA, Kittler JT. Axonal autophagosome maturation defect through failure of ATG9A sorting underpins pathology in AP-4 deficiency syndrome. Autophagy 2020; 16:391-407. [PMID: 31142229 PMCID: PMC6999640 DOI: 10.1080/15548627.2019.1615302] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 04/02/2019] [Accepted: 04/29/2019] [Indexed: 12/26/2022] Open
Abstract
Adaptor protein (AP) complexes mediate key sorting decisions in the cell through selective incorporation of transmembrane proteins into vesicles. Little is known of the roles of AP-4, despite its loss of function leading to a severe early onset neurological disorder, AP-4 deficiency syndrome. Here we demonstrate an AP-4 epsilon subunit knockout mouse model that recapitulates characteristic neuroanatomical phenotypes of AP-4 deficiency patients. We show that ATG9A, critical for autophagosome biogenesis, is an AP-4 cargo, which is retained within the trans-Golgi network (TGN) in vivo and in culture when AP-4 function is lost. TGN retention results in depletion of axonal ATG9A, leading to defective autophagosome generation and aberrant expansions of the distal axon. The reduction in the capacity to generate axonal autophagosomes leads to defective axonal extension and de novo generation of distal axonal swellings containing accumulated ER, underlying the impaired axonal integrity in AP-4 deficiency syndrome.Abbreviations: AP: adaptor protein; AP4B1: adaptor-related protein complex AP-4, beta 1; AP4E1: adaptor-related protein complex AP-4, epsilon 1; ATG: autophagy-related; EBSS: Earle's balanced salt solution; ER: endoplasmic reticulum; GFAP: glial fibrillary acidic protein; GOLGA1/Golgin-97/GOLG97: golgi autoantigen, golgin subfamily a, 1; GOLGA2/GM130: golgi autoantigen, golgin subfamily a, 2; HSP: hereditary spastic paraplegia; LC3/MAP1LC3B: microtubule-associated protein 1 light chain 3 beta; MAP2: microtubule-associated protein 2; MAPK8IP1/JIP1: mitogen-acitvated protein kinase 8 interacting protein 1; NEFH/NF200: neurofilament, heavy polypeptide; RBFOX3/NeuN (RNA binding protein, fox-1 homolog [C. elegans] 3); SQSTM1/p62: sequestosome 1; TGN: trans-Golgi network; WIPI2: WD repeat domain, phosphoinositide interacting protein 2.
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Affiliation(s)
| | - James Drew
- Neuroscience, Physiology and Pharmacology, UCL, London, UK
| | - Flavie Lesept
- Neuroscience, Physiology and Pharmacology, UCL, London, UK
| | - Ian J. White
- MRC Laboratory for Molecular Cell Biology, UCL, London, UK
| | | | - Sharon A. Tooze
- Molecular Cell Biology of Autophagy, The Francis Crick Institute, London, UK
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Casterton RL, Hunt RJ, Fanto M. Pathomechanism Heterogeneity in the Amyotrophic Lateral Sclerosis and Frontotemporal Dementia Disease Spectrum: Providing Focus Through the Lens of Autophagy. J Mol Biol 2020; 432:2692-2713. [PMID: 32119873 DOI: 10.1016/j.jmb.2020.02.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 02/15/2020] [Accepted: 02/17/2020] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) constitute aggressive neurodegenerative pathologies that lead to the progressive degeneration of upper and lower motor neurons and of neocortical areas, respectively. In the past decade, the identification of several genes that cause these disorders indicated that the two diseases overlap in a multifaceted spectrum of conditions. The autophagy-lysosome system has been identified as a main intersection for the onset and progression of neurodegeneration in ALS/FTD. Genetic evidence has revealed that several genes with a mechanistic role at different stages of the autophagy process are mutated in patients with ALS/FTD. Moreover, the three main proteins aggregating in ALS/FTD, including in sporadic cases, are also targeted by autophagy and affect this process. Here, we examine the varied dysfunctions and degrees of involvement of the autophagy-lysosome system that have been discovered in ALS/FTD. We argue that these findings shed light on the pathological mechanisms in the ALS/FTD spectrum and conclude that they have important consequences both for treatment options and for the basic biomolecular understanding of how this process intersects with RNA metabolism, the other major cellular process reported to be dysfunctional in part of the ALS/FTD spectrum.
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Affiliation(s)
- Rebecca L Casterton
- Department of Basic and Clinical Neuroscience, King's College London, 125 Coldharbour Lane, SE5 9NU London, United Kingdom
| | - Rachel J Hunt
- Department of Basic and Clinical Neuroscience, King's College London, 125 Coldharbour Lane, SE5 9NU London, United Kingdom
| | - Manolis Fanto
- Department of Basic and Clinical Neuroscience, King's College London, 125 Coldharbour Lane, SE5 9NU London, United Kingdom; Institut du Cerveau et de la Moelle épinière (ICM), 47, bd de l'hôpital, F-75013 Paris, France.
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61
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Protein Kinase C Isozymes and Autophagy during Neurodegenerative Disease Progression. Cells 2020; 9:cells9030553. [PMID: 32120776 PMCID: PMC7140419 DOI: 10.3390/cells9030553] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 01/27/2020] [Accepted: 02/04/2020] [Indexed: 12/16/2022] Open
Abstract
Protein kinase C (PKC) isozymes are members of the Serine/Threonine kinase family regulating cellular events following activation of membrane bound phospholipids. The breakdown of the downstream signaling pathways of PKC relates to several disease pathogeneses particularly neurodegeneration. PKC isozymes play a critical role in cell death and survival mechanisms, as well as autophagy. Numerous studies have reported that neurodegenerative disease formation is caused by failure of the autophagy mechanism. This review outlines PKC signaling in autophagy and neurodegenerative disease development and introduces some polyphenols as effectors of PKC isozymes for disease therapy.
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62
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Kyriakou K, W. Lederer C, Kleanthous M, Drousiotou A, Malekkou A. Acid Ceramidase Depletion Impairs Neuronal Survival and Induces Morphological Defects in Neurites Associated with Altered Gene Transcription and Sphingolipid Content. Int J Mol Sci 2020; 21:E1607. [PMID: 32111095 PMCID: PMC7084529 DOI: 10.3390/ijms21051607] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 02/22/2020] [Accepted: 02/22/2020] [Indexed: 12/11/2022] Open
Abstract
The ASAH1 gene encodes acid ceramidase (AC), an enzyme that is implicated in the metabolism of ceramide (Cer). Mutations in the ASAH1 gene cause two different disorders, Farber disease (FD), a rare lysosomal storage disorder, and a rare form of spinal muscular atrophy combined with progressive myoclonic epilepsy (SMA-PME). In the absence of human in vitro neuronal disease models and to gain mechanistic insights into pathological effects of ASAH1 deficiency, we established and characterized a stable ASAH1 knockdown (ASAH1KD) SH-SY5Y cell line. ASAH1KD cells displayed reduced proliferation due to elevated apoptosis and G1/S cell cycle arrest. Distribution of LAMP1-positive lysosomes towards the cell periphery and significantly shortened and less branched neurites upon differentiation, implicate AC for lysosome positioning and neuronal development, respectively. Lipidomic analysis revealed changes in the intracellular levels of distinct sphingolipid species, importantly without Cer accumulation, in line with altered gene transcription within the sphingolipid pathway. Additionally, the transcript levels for Rho GTPases (RhoA, Rac1, and Cdc42), which are key regulators of axonal orientation, neurite branching and lysosome positioning were found to be dysregulated. This study shows the critical role of AC in neurons and suggests how AC depletion leads to defects seen in neuropathology of SMA-PME and FD.
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Affiliation(s)
- Kalia Kyriakou
- Cyprus School of Molecular Medicine, P.O. Box 23462, 1683 Nicosia, Cyprus; (K.K.); (C.W.L.); (M.K.); (A.D.)
- Biochemical Genetics Department, The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, 1683 Nicosia, Cyprus
| | - Carsten W. Lederer
- Cyprus School of Molecular Medicine, P.O. Box 23462, 1683 Nicosia, Cyprus; (K.K.); (C.W.L.); (M.K.); (A.D.)
- Molecular Genetics Thalassaemia Department, The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, 1683 Nicosia, Cyprus
| | - Marina Kleanthous
- Cyprus School of Molecular Medicine, P.O. Box 23462, 1683 Nicosia, Cyprus; (K.K.); (C.W.L.); (M.K.); (A.D.)
- Molecular Genetics Thalassaemia Department, The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, 1683 Nicosia, Cyprus
| | - Anthi Drousiotou
- Cyprus School of Molecular Medicine, P.O. Box 23462, 1683 Nicosia, Cyprus; (K.K.); (C.W.L.); (M.K.); (A.D.)
- Biochemical Genetics Department, The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, 1683 Nicosia, Cyprus
| | - Anna Malekkou
- Cyprus School of Molecular Medicine, P.O. Box 23462, 1683 Nicosia, Cyprus; (K.K.); (C.W.L.); (M.K.); (A.D.)
- Biochemical Genetics Department, The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, 1683 Nicosia, Cyprus
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63
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DYNLRB1 is essential for dynein mediated transport and neuronal survival. Neurobiol Dis 2020; 140:104816. [PMID: 32088381 PMCID: PMC7273200 DOI: 10.1016/j.nbd.2020.104816] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 02/08/2020] [Accepted: 02/18/2020] [Indexed: 12/19/2022] Open
Abstract
The cytoplasmic dynein motor complex transports essential signals and organelles from the cell periphery to the perinuclear region, hence is critical for the survival and function of highly polarized cells such as neurons. Dynein Light Chain Roadblock-Type 1 (DYNLRB1) is thought to be an accessory subunit required for specific cargos, but here we show that it is essential for general dynein-mediated transport and sensory neuron survival. Homozygous Dynlrb1 null mice are not viable and die during early embryonic development. Furthermore, heterozygous or adult knockdown animals display reduced neuronal growth, and selective depletion of Dynlrb1 in proprioceptive neurons compromises their survival. Conditional depletion of Dynlrb1 in sensory neurons causes deficits in several signaling pathways, including β-catenin subcellular localization, and a severe impairment in the axonal transport of both lysosomes and retrograde signaling endosomes. Hence, DYNLRB1 is an essential component of the dynein complex, and given dynein's critical functions in neuronal physiology, DYNLRB1 could have a prominent role in the etiology of human neurodegenerative diseases.
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64
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Vicencio E, Beltrán S, Labrador L, Manque P, Nassif M, Woehlbier U. Implications of Selective Autophagy Dysfunction for ALS Pathology. Cells 2020; 9:cells9020381. [PMID: 32046060 PMCID: PMC7072226 DOI: 10.3390/cells9020381] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 02/01/2020] [Accepted: 02/03/2020] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a lethal neurodegenerative disorder that progressively affects motor neurons in the brain and spinal cord. Due to the biological complexity of the disease, its etiology remains unknown. Several cellular mechanisms involved in the neurodegenerative process in ALS have been found, including the loss of RNA and protein homeostasis, as well as mitochondrial dysfunction. Insoluble protein aggregates, damaged mitochondria, and stress granules, which contain RNA and protein components, are recognized and degraded by the autophagy machinery in a process known as selective autophagy. Autophagy is a highly dynamic process whose dysregulation has now been associated with neurodegenerative diseases, including ALS, by numerous studies. In ALS, the autophagy process has been found deregulated in both familial and sporadic cases of the disease. Likewise, mutations in genes coding for proteins involved in the autophagy machinery have been reported in ALS patients, including selective autophagy receptors. In this review, we focus on the role of selective autophagy in ALS pathology.
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Affiliation(s)
- Emiliano Vicencio
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile; (E.V.); (S.B.); (L.L.); (P.M.)
| | - Sebastián Beltrán
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile; (E.V.); (S.B.); (L.L.); (P.M.)
| | - Luis Labrador
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile; (E.V.); (S.B.); (L.L.); (P.M.)
| | - Patricio Manque
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile; (E.V.); (S.B.); (L.L.); (P.M.)
- Center for Genomics and Bioinformatics, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile
| | - Melissa Nassif
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile; (E.V.); (S.B.); (L.L.); (P.M.)
- Escuela de Biotecnología, Facultad de Ciencias, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile
- Correspondence: (U.W.); (M.N.)
| | - Ute Woehlbier
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile; (E.V.); (S.B.); (L.L.); (P.M.)
- Escuela de Biotecnología, Facultad de Ciencias, Universidad Mayor, Camino la Piramide 5750, Huechuraba 8580745, Santiago, Chile
- Correspondence: (U.W.); (M.N.)
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Seranova E, Palhegyi AM, Verma S, Dimova S, Lasry R, Naama M, Sun C, Barrett T, Rosenstock TR, Kumar D, Cohen MA, Buganim Y, Sarkar S. Human Induced Pluripotent Stem Cell Models of Neurodegenerative Disorders for Studying the Biomedical Implications of Autophagy. J Mol Biol 2020; 432:2754-2798. [PMID: 32044344 DOI: 10.1016/j.jmb.2020.01.024] [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: 12/20/2019] [Revised: 01/22/2020] [Accepted: 01/23/2020] [Indexed: 12/12/2022]
Abstract
Autophagy is an intracellular degradation process that is essential for cellular survival, tissue homeostasis, and human health. The housekeeping functions of autophagy in mediating the clearance of aggregation-prone proteins and damaged organelles are vital for post-mitotic neurons. Improper functioning of this process contributes to the pathology of myriad human diseases, including neurodegeneration. Impairment in autophagy has been reported in several neurodegenerative diseases where pharmacological induction of autophagy has therapeutic benefits in cellular and transgenic animal models. However, emerging studies suggest that the efficacy of autophagy inducers, as well as the nature of the autophagy defects, may be context-dependent, and therefore, studies in disease-relevant experimental systems may provide more insights for clinical translation to patients. With the advancements in human stem cell technology, it is now possible to establish disease-affected cellular platforms from patients for investigating disease mechanisms and identifying candidate drugs in the appropriate cell types, such as neurons that are otherwise not accessible. Towards this, patient-derived human induced pluripotent stem cells (hiPSCs) have demonstrated considerable promise in constituting a platform for effective disease modeling and drug discovery. Multiple studies have utilized hiPSC models of neurodegenerative diseases to study autophagy and evaluate the therapeutic efficacy of autophagy inducers in neuronal cells. This review provides an overview of the regulation of autophagy, generation of hiPSCs via cellular reprogramming, and neuronal differentiation. It outlines the findings in various neurodegenerative disorders where autophagy has been studied using hiPSC models.
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Affiliation(s)
- Elena Seranova
- Institute of Cancer and Genomic Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Adina Maria Palhegyi
- Institute of Cancer and Genomic Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Surbhi Verma
- Institute of Cancer and Genomic Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom; Cellular Immunology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Simona Dimova
- Institute of Cancer and Genomic Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Rachel Lasry
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, The Hebrew University Hadassah Medical School, Jerusalem, 91120, Israel
| | - Moriyah Naama
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, The Hebrew University Hadassah Medical School, Jerusalem, 91120, Israel
| | - Congxin Sun
- Institute of Cancer and Genomic Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Timothy Barrett
- Institute of Cancer and Genomic Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Tatiana Rosado Rosenstock
- Department of Physiological Science, Santa Casa de São Paulo School of Medical Sciences, São Paulo, SP, 01221-020, Brazil
| | - Dhiraj Kumar
- Cellular Immunology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Malkiel A Cohen
- Whitehead Institute for Biomedical Research, Cambridge, MA, 02142, USA
| | - Yosef Buganim
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, The Hebrew University Hadassah Medical School, Jerusalem, 91120, Israel
| | - Sovan Sarkar
- Institute of Cancer and Genomic Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
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Cai Q, Jeong YY. Mitophagy in Alzheimer's Disease and Other Age-Related Neurodegenerative Diseases. Cells 2020; 9:cells9010150. [PMID: 31936292 PMCID: PMC7017092 DOI: 10.3390/cells9010150] [Citation(s) in RCA: 136] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 01/03/2020] [Accepted: 01/05/2020] [Indexed: 02/07/2023] Open
Abstract
Mitochondrial dysfunction is a central aspect of aging and neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and Huntington's disease. Mitochondria are the main cellular energy powerhouses, supplying most of ATP by oxidative phosphorylation, which is required to fuel essential neuronal functions. Efficient removal of aged and dysfunctional mitochondria through mitophagy, a cargo-selective autophagy, is crucial for mitochondrial maintenance and neuronal health. Mechanistic studies into mitophagy have highlighted an integrated and elaborate cellular network that can regulate mitochondrial turnover. In this review, we provide an updated overview of the recent discoveries and advancements on the mitophagy pathways and discuss the molecular mechanisms underlying mitophagy defects in Alzheimer's disease and other age-related neurodegenerative diseases, as well as the therapeutic potential of mitophagy-enhancing strategies to combat these disorders.
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Foster AD, Rea SL. The role of sequestosome 1/p62 protein in amyotrophic lateral sclerosis and frontotemporal dementia pathogenesis. Neural Regen Res 2020; 15:2186-2194. [PMID: 32594029 PMCID: PMC7749485 DOI: 10.4103/1673-5374.284977] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis and frontotemporal lobar degeneration are multifaceted diseases with genotypic, pathological and clinical overlap. One such overlap is the presence of SQSTM1/p62 mutations. While traditionally mutations manifesting in the ubiquitin-associated domain of p62 were associated with Paget’s disease of bone, mutations affecting all functional domains of p62 have now been identified in amyotrophic lateral sclerosis and frontotemporal lobar degeneration patients. p62 is a multifunctional protein that facilitates protein degradation through autophagy and the ubiquitin-proteasome system, and also regulates cell survival via the Nrf2 antioxidant response pathway, the nuclear factor-kappa B signaling pathway and apoptosis. Dysfunction in these signaling and protein degradation pathways have been observed in amyotrophic lateral sclerosis and frontotemporal lobar degeneration, and mutations that affect the role of p62 in these pathways may contribute to disease pathogenesis. In this review we discuss the role of p62 in these pathways, the effects of p62 mutations and the effect of mutations in the p62 modulator TANK-binding kinase 1, in relation to amyotrophic lateral sclerosis-frontotemporal lobar degeneration pathogenesis.
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Affiliation(s)
- Adriana Delice Foster
- Harry Perkins Institute of Medical Research, University of Western Australia; Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, Western Australia, Australia; Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Murdoch, Western Australia, Australia
| | - Sarah Lyn Rea
- Harry Perkins Institute of Medical Research, University of Western Australia; Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Nedlands, Western Australia, Australia; Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Murdoch, Western Australia, Australia
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Djajadikerta A, Keshri S, Pavel M, Prestil R, Ryan L, Rubinsztein DC. Autophagy Induction as a Therapeutic Strategy for Neurodegenerative Diseases. J Mol Biol 2019; 432:2799-2821. [PMID: 31887286 DOI: 10.1016/j.jmb.2019.12.035] [Citation(s) in RCA: 142] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Revised: 10/28/2019] [Accepted: 12/03/2019] [Indexed: 12/12/2022]
Abstract
Autophagy is a major, conserved cellular pathway by which cells deliver cytoplasmic contents to lysosomes for degradation. Genetic studies have revealed extensive links between autophagy and neurodegenerative disease, and disruptions to autophagy may contribute to pathology in some cases. Autophagy degrades many of the toxic, aggregate-prone proteins responsible for such diseases, including mutant huntingtin (mHTT), alpha-synuclein (α-syn), tau, and others, raising the possibility that autophagy upregulation may help to reduce levels of toxic protein species, and thereby alleviate disease. This review examines autophagy induction as a potential therapy in several neurodegenerative diseases-Alzheimer's disease, Parkinson's disease, polyglutamine diseases, and amyotrophic lateral sclerosis (ALS). Evidence in cells and in vivo demonstrates promising results in many disease models, in which autophagy upregulation is able to reduce the levels of toxic proteins, ameliorate signs of disease, and delay disease progression. However, the effective therapeutic use of autophagy induction requires detailed knowledge of how the disease affects the autophagy-lysosome pathway, as activating autophagy when the pathway cannot go to completion (e.g., when lysosomal degradation is impaired) may instead exacerbate disease in some cases. Investigating the interactions between autophagy and disease pathogenesis is thus a critical area for further research.
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Affiliation(s)
- Alvin Djajadikerta
- Department of Medical Genetics, Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, UK; UK Dementia Research Institute, Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, UK
| | - Swati Keshri
- Department of Medical Genetics, Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, UK; UK Dementia Research Institute, Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, UK
| | - Mariana Pavel
- Department of Immunology, "Grigore T. Popa" University of Medicine and Pharmacy, Iasi, 700115, Romania
| | - Ryan Prestil
- Department of Medical Genetics, Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, UK; UK Dementia Research Institute, Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, UK
| | - Laura Ryan
- Department of Medical Genetics, Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, UK; UK Dementia Research Institute, Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, UK
| | - David C Rubinsztein
- Department of Medical Genetics, Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, UK; UK Dementia Research Institute, Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, UK.
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Wang J, Rousseau J, Kim E, Ehresmann S, Cheng YT, Duraine L, Zuo Z, Park YJ, Li-Kroeger D, Bi W, Wong LJ, Rosenfeld J, Gleeson J, Faqeih E, Alkuraya FS, Wierenga KJ, Chen J, Afenjar A, Nava C, Doummar D, Keren B, Juusola J, Grompe M, Bellen HJ, Campeau PM. Loss of Oxidation Resistance 1, OXR1, Is Associated with an Autosomal-Recessive Neurological Disease with Cerebellar Atrophy and Lysosomal Dysfunction. Am J Hum Genet 2019; 105:1237-1253. [PMID: 31785787 PMCID: PMC6904826 DOI: 10.1016/j.ajhg.2019.11.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Accepted: 11/01/2019] [Indexed: 12/28/2022] Open
Abstract
We report an early-onset autosomal-recessive neurological disease with cerebellar atrophy and lysosomal dysfunction. We identified bi-allelic loss-of-function (LoF) variants in Oxidative Resistance 1 (OXR1) in five individuals from three families; these individuals presented with a history of severe global developmental delay, current intellectual disability, language delay, cerebellar atrophy, and seizures. While OXR1 is known to play a role in oxidative stress resistance, its molecular functions are not well established. OXR1 contains three conserved domains: LysM, GRAM, and TLDc. The gene encodes at least six transcripts, including some that only consist of the C-terminal TLDc domain. We utilized Drosophila to assess the phenotypes associated with loss of mustard (mtd), the fly homolog of OXR1. Strong LoF mutants exhibit late pupal lethality or pupal eclosion defects. Interestingly, although mtd encodes 26 transcripts, severe LoF and null mutations can be rescued by a single short human OXR1 cDNA that only contains the TLDc domain. Similar rescue is observed with the TLDc domain of NCOA7, another human homolog of mtd. Loss of mtd in neurons leads to massive cell loss, early death, and an accumulation of aberrant lysosomal structures, similar to what we observe in fibroblasts of affected individuals. Our data indicate that mtd and OXR1 are required for proper lysosomal function; this is consistent with observations that NCOA7 is required for lysosomal acidification.
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Affiliation(s)
- Julia Wang
- Program in Developmental Biology, Medical Scientist Training Program, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - Justine Rousseau
- Centre Hospitalier Universitaire Saint-Justine Research Center, CHU Sainte-Justine, Montreal, QC H3T 1J4, Canada
| | - Emily Kim
- Biochemistry and Cell Biology, Rice University, Houston, TX 77005, USA
| | - Sophie Ehresmann
- Centre Hospitalier Universitaire Saint-Justine Research Center, CHU Sainte-Justine, Montreal, QC H3T 1J4, Canada
| | - Yi-Ting Cheng
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lita Duraine
- Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zhongyuan Zuo
- Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ye-Jin Park
- Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - David Li-Kroeger
- Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Weimin Bi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Lee-Jun Wong
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jill Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Joseph Gleeson
- Rady Institute of Genomic Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Eissa Faqeih
- Section of Medical Genetics, Children's Hospital, King Fahad Medical City, Riyadh, 11525, Saudi Arabia
| | - Fowzan S Alkuraya
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, 11525, Saudi Arabia
| | - Klaas J Wierenga
- Department of Pediatrics, Oklahoma University Health Sciences Center (OUHSC), Oklahoma City, OK 26901, USA; Department of Clinical Genomics, Mayo Clinic Florida, Jacksonville, FL 32224, USA
| | - Jiani Chen
- Department of Pediatrics, Oklahoma University Health Sciences Center (OUHSC), Oklahoma City, OK 26901, USA; Division of Genomic Diagnostics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Alexandra Afenjar
- Assistance Publique des Hôpitaux de Paris, Unité de Génétique Clinique, Hôpital Armand Trousseau, Groupe Hospitalier Universitaire Paris, 75012, France; Département de Génétique et Embryologie Médicale, CRMR des Malformations et Maladies Congénitales du Cervelet, GRC ConCer-LD, Sorbonne Universités, Hôpital Trousseau, Paris, 75012 France
| | - Caroline Nava
- Assistance Publique des Hôpitaux de Paris, Unité de Génétique Clinique, Hôpital Armand Trousseau, Groupe Hospitalier Universitaire Paris, 75012, France
| | - Diane Doummar
- Assistance Publique des Hôpitaux de Paris, Service de Neuropédiatrie, Hôpital Armand Trousseau, Groupe Hospitalier Universitaire Paris, 75012 France
| | - Boris Keren
- Assistance Publique des Hôpitaux de Paris, Unité de Génétique Clinique, Hôpital Armand Trousseau, Groupe Hospitalier Universitaire Paris, 75012, France
| | | | - Markus Grompe
- Department of Pediatrics, Oregon Health and Science University, Portland, Oregon 97201, USA; Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, Oregon 97201, USA
| | - Hugo J Bellen
- Jan and Dan Duncan Neurological Research Institute, Baylor College of Medicine, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute and Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA.
| | - Philippe M Campeau
- Centre Hospitalier Universitaire Saint-Justine Research Center, CHU Sainte-Justine, Montreal, QC H3T 1J4, Canada.
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Allison R, Edgar JR, Reid E. Spastin MIT Domain Disease-Associated Mutations Disrupt Lysosomal Function. Front Neurosci 2019; 13:1179. [PMID: 31787869 PMCID: PMC6856053 DOI: 10.3389/fnins.2019.01179] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 10/18/2019] [Indexed: 12/25/2022] Open
Abstract
The hereditary spastic paraplegias (HSPs) are genetic motor neuron diseases characterized by progressive degeneration of corticospinal tract axons. Mutations in SPAST, encoding the microtubule-severing ATPase spastin, are the most common causes of HSP. The broad SPAST mutational spectrum indicates a haploinsufficiency pathogenic mechanism in most cases. Most missense mutations cluster in the ATPase domain, where they disrupt the protein's ability to sever microtubules. However, several putative missense mutations in the protein's microtubule interacting and trafficking (MIT) domain have also been described, but the pathogenicity of these mutations has not been verified with functional studies. Spastin promotes endosomal tubule fission, and defects in this lead to lysosomal enzyme mistrafficking and downstream lysosomal abnormalities. We investigated the function of three disease-associated spastin MIT mutants and found that none was able to promote normal endosomal tubule fission, lysosomal enzyme receptor trafficking, or lysosomal morphology. One of the mutations affected recruitment of spastin to endosomes, a property that requires the canonical function of the MIT domain in binding endosomal sorting complex required for transport (ESCRT)-III proteins. However, the other mutants did not affect spastin's endosomal recruitment, raising the possibility of pathologically important non-canonical roles for the MIT domain. In conclusion, we demonstrate that spastin MIT mutants cause functional abnormalities related to the pathogenesis of HSP. These mutations do not directly affect spastin's microtubule-severing capacity, and so we identify a new molecular pathological mechanism by which spastin mutations may cause disease.
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Affiliation(s)
- Rachel Allison
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - James R Edgar
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Evan Reid
- Department of Medical Genetics, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
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The Endolysosomal System and Proteostasis: From Development to Degeneration. J Neurosci 2019; 38:9364-9374. [PMID: 30381428 DOI: 10.1523/jneurosci.1665-18.2018] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 09/17/2018] [Accepted: 09/20/2018] [Indexed: 12/12/2022] Open
Abstract
How do neurons adapt their endolysosomal system to address the particular challenge of membrane transport across their elaborate cellular landscape and to maintain proteostasis for the lifetime of the organism? Here we review recent findings that address this central question. We discuss the cellular and molecular mechanisms of endolysosomal trafficking and the autophagy pathway in neurons, as well as their role in neuronal development and degeneration. These studies highlight the importance of understanding the basic cell biology of endolysosomal trafficking and autophagy and their roles in the maintenance of proteostasis within the context of neurons, which will be critical for developing effective therapies for various neurodevelopmental and neurodegenerative disorders.
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Feng F, Zhang M, Yang C, Heng X, Wu X. The dual roles of autophagy in gliomagenesis and clinical therapy strategies based on autophagic regulation mechanisms. Biomed Pharmacother 2019; 120:109441. [PMID: 31541887 DOI: 10.1016/j.biopha.2019.109441] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 09/02/2019] [Accepted: 09/06/2019] [Indexed: 01/14/2023] Open
Abstract
Autophagy, a self-digestion intracellular catabolic process, plays a crucial role in cellular homeostasis under conditions of starvation, oxidative stress and genotoxic stress. The capability of maintaining homeostasis contributes to preventing malignant behavior in normal cells. Many studies have provided compelling evidence that autophagy is involved in brain tumor recurrence and chemotherapy and radiotherapy resistance. Gliomas, as the primary central nervous system (CNS) tumors, are characterized by rapid, aggressive growth and recurrence and have a poor prognosis and bleak outlook even with modern multimodality strategies involving maximal surgical resection, radiotherapy and alkylating agent-based chemotherapy. Autophagy-associated signaling pathways, such as the extracellular signal-regulated kinase1/2 (ERK1/2) pathway, class I phosphatidylinositol 3-phosphate kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway and nuclear factor kappa-B (NF-κB) pathway, act as tumor suppressors or protect tumor cells against chemotherapy/radiotherapy-induced cytotoxicity in gliomagenesis. Through these pathways, both lethal autophagy and protective autophagy play crucial roles in tumor initiation, chemoresistance and glioma stem cell differentiation. Moreover, lethal autophagy and protective autophagy have been identified as novel therapeutic targets in glioma according to the mechanisms described above. Here, we discuss the multiple impacts of the autophagic response on distinct phases of gliomagenesis and the advanced progress of therapies based on this concept.
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Affiliation(s)
- Fan Feng
- Institute of Clinical Medicine College, Qingdao University, # 38, Dengzhou Road, Qingdao 266071, Shandong, China
| | - Moxuan Zhang
- Weifang Medical University, 261042, # 7166, Baotong Western Road, Weifang, Shandong, China
| | - Chuanchao Yang
- Weifang Medical University, 261042, # 7166, Baotong Western Road, Weifang, Shandong, China
| | - Xueyuan Heng
- Department of Neurosurgery, Linyi People's Hospital, # 27, Jiefang Eastern Road, Linyi 276000, Shandong, China.
| | - Xiujie Wu
- Department of Neurosurgery, Linyi People's Hospital, # 27, Jiefang Eastern Road, Linyi 276000, Shandong, China.
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Chamberlain KA, Sheng ZH. Mechanisms for the maintenance and regulation of axonal energy supply. J Neurosci Res 2019; 97:897-913. [PMID: 30883896 PMCID: PMC6565461 DOI: 10.1002/jnr.24411] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 02/04/2019] [Accepted: 02/18/2019] [Indexed: 12/25/2022]
Abstract
The unique polarization and high-energy demand of neurons necessitates specialized mechanisms to maintain energy homeostasis throughout the cell, particularly in the distal axon. Mitochondria play a key role in meeting axonal energy demand by generating adenosine triphosphate through oxidative phosphorylation. Recent evidence demonstrates how axonal mitochondrial trafficking and anchoring are coordinated to sense and respond to altered energy requirements. If and when these mechanisms are impacted in pathological conditions, such as injury and neurodegenerative disease, is an emerging research frontier. Recent evidence also suggests that axonal energy demand may be supplemented by local glial cells, including astrocytes and oligodendrocytes. In this review, we provide an updated discussion of how oxidative phosphorylation, aerobic glycolysis, and oligodendrocyte-derived metabolic support contribute to the maintenance of axonal energy homeostasis.
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Affiliation(s)
- Kelly Anne Chamberlain
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Room 2B-215, 35 Convent Drive, Bethesda, Maryland 20892-3706, USA
| | - Zu-Hang Sheng
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Room 2B-215, 35 Convent Drive, Bethesda, Maryland 20892-3706, USA
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Affiliation(s)
- Fang Lin
- Department of Pharmacology, Laboratory of Aging and Nervous Diseases (SZS0703)Soochow University School of Pharmaceutical ScienceSu ZhouChina
| | - Shou‐Qing Luo
- Peninsula Schools of Medicine and Dentistry, Institute of Translational and Stratified MedicineUniversity of PlymouthPlymouthUK
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Qi W, Yan L, Liu Y, Zhou X, Li R, Wang Y, Bai L, Chen J, Nie X. Simvastatin aggravates impaired autophagic flux in NSC34-hSOD1G93A cells through inhibition of geranylgeranyl pyrophosphate synthesis. Neuroscience 2019; 409:130-141. [DOI: 10.1016/j.neuroscience.2019.04.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 04/05/2019] [Accepted: 04/13/2019] [Indexed: 11/28/2022]
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Mitochondrial Transport and Turnover in the Pathogenesis of Amyotrophic Lateral Sclerosis. BIOLOGY 2019; 8:biology8020036. [PMID: 31083575 PMCID: PMC6627920 DOI: 10.3390/biology8020036] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 01/20/2019] [Accepted: 02/03/2019] [Indexed: 02/06/2023]
Abstract
Neurons are high-energy consuming cells, heavily dependent on mitochondria for ATP generation and calcium buffering. These mitochondrial functions are particularly critical at specific cellular sites, where ionic currents impose a large energetic burden, such as at synapses. The highly polarized nature of neurons, with extremely large axoplasm relative to the cell body, requires mitochondria to be efficiently transported along microtubules to reach distant sites. Furthermore, neurons are post-mitotic cells that need to maintain pools of healthy mitochondria throughout their lifespan. Hence, mitochondrial transport and turnover are essential processes for neuronal survival and function. In neurodegenerative diseases, the maintenance of a healthy mitochondrial network is often compromised. Numerous lines of evidence indicate that mitochondrial impairment contributes to neuronal demise in a variety of neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), where degeneration of motor neurons causes a fatal muscle paralysis. Dysfunctional mitochondria accumulate in motor neurons affected by genetic or sporadic forms of ALS, strongly suggesting that the inability to maintain a healthy pool of mitochondria plays a pathophysiological role in the disease. This article critically reviews current hypotheses on mitochondrial involvement in the pathogenesis of ALS, focusing on the alterations of mitochondrial axonal transport and turnover in motor neurons.
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78
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Nguyen DKH, Thombre R, Wang J. Autophagy as a common pathway in amyotrophic lateral sclerosis. Neurosci Lett 2019; 697:34-48. [PMID: 29626651 PMCID: PMC6170747 DOI: 10.1016/j.neulet.2018.04.006] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 03/26/2018] [Accepted: 04/02/2018] [Indexed: 12/11/2022]
Abstract
Age-dependent neurodegenerative diseases are associated with a decline in protein quality control systems including autophagy. Amyotrophic lateral sclerosis (ALS) is a motor neuron degenerative disease of complex etiology with increasing connections to other neurodegenerative conditions such as frontotemporal dementia. Among the diverse genetic causes for ALS, a striking feature is the common connection to autophagy and its associated pathways. There is a recurring theme of protein misfolding as in other neurodegenerative diseases, but importantly there is a distinct common thread among ALS genes that connects them to the cascade of autophagy. However, the roles of autophagy in ALS remain enigmatic and it is still unclear whether activation or inhibition of autophagy would be a reliable avenue to ameliorate the disease. The main evidence that links autophagy to different genetic forms of ALS is discussed.
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Affiliation(s)
- Dao K H Nguyen
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, 21205, USA; Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Ravi Thombre
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, 21205, USA; Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Jiou Wang
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, 21205, USA; Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA.
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79
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Beltran S, Nassif M, Vicencio E, Arcos J, Labrador L, Cortes BI, Cortez C, Bergmann CA, Espinoza S, Hernandez MF, Matamala JM, Bargsted L, Matus S, Rojas-Rivera D, Bertrand MJM, Medinas DB, Hetz C, Manque PA, Woehlbier U. Network approach identifies Pacer as an autophagy protein involved in ALS pathogenesis. Mol Neurodegener 2019; 14:14. [PMID: 30917850 PMCID: PMC6437924 DOI: 10.1186/s13024-019-0313-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 03/11/2019] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Amyotrophic lateral sclerosis (ALS) is a multifactorial fatal motoneuron disease without a cure. Ten percent of ALS cases can be pointed to a clear genetic cause, while the remaining 90% is classified as sporadic. Our study was aimed to uncover new connections within the ALS network through a bioinformatic approach, by which we identified C13orf18, recently named Pacer, as a new component of the autophagic machinery and potentially involved in ALS pathogenesis. METHODS Initially, we identified Pacer using a network-based bioinformatic analysis. Expression of Pacer was then investigated in vivo using spinal cord tissue from two ALS mouse models (SOD1G93A and TDP43A315T) and sporadic ALS patients. Mechanistic studies were performed in cell culture using the mouse motoneuron cell line NSC34. Loss of function of Pacer was achieved by knockdown using short-hairpin constructs. The effect of Pacer repression was investigated in the context of autophagy, SOD1 aggregation, and neuronal death. RESULTS Using an unbiased network-based approach, we integrated all available ALS data to identify new functional interactions involved in ALS pathogenesis. We found that Pacer associates to an ALS-specific subnetwork composed of components of the autophagy pathway, one of the main cellular processes affected in the disease. Interestingly, we found that Pacer levels are significantly reduced in spinal cord tissue from sporadic ALS patients and in tissues from two ALS mouse models. In vitro, Pacer deficiency lead to impaired autophagy and accumulation of ALS-associated protein aggregates, which correlated with the induction of cell death. CONCLUSIONS This study, therefore, identifies Pacer as a new regulator of proteostasis associated with ALS pathology.
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Affiliation(s)
- S Beltran
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, P.O.BOX 70086, Santiago, Chile.,Center for Genomics and Bioinformatics, Faculty of Science, Universidad Mayor, Camino la Piramide, 5750, Santiago, Chile
| | - M Nassif
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, P.O.BOX 70086, Santiago, Chile.,Center for Genomics and Bioinformatics, Faculty of Science, Universidad Mayor, Camino la Piramide, 5750, Santiago, Chile
| | - E Vicencio
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, P.O.BOX 70086, Santiago, Chile.,Center for Genomics and Bioinformatics, Faculty of Science, Universidad Mayor, Camino la Piramide, 5750, Santiago, Chile
| | - J Arcos
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, P.O.BOX 70086, Santiago, Chile.,Center for Genomics and Bioinformatics, Faculty of Science, Universidad Mayor, Camino la Piramide, 5750, Santiago, Chile
| | - L Labrador
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, P.O.BOX 70086, Santiago, Chile.,Center for Genomics and Bioinformatics, Faculty of Science, Universidad Mayor, Camino la Piramide, 5750, Santiago, Chile
| | - B I Cortes
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, P.O.BOX 70086, Santiago, Chile.,Center for Genomics and Bioinformatics, Faculty of Science, Universidad Mayor, Camino la Piramide, 5750, Santiago, Chile
| | - C Cortez
- Center for Genomics and Bioinformatics, Faculty of Science, Universidad Mayor, Camino la Piramide, 5750, Santiago, Chile
| | - C A Bergmann
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, P.O.BOX 70086, Santiago, Chile.,Center for Genomics and Bioinformatics, Faculty of Science, Universidad Mayor, Camino la Piramide, 5750, Santiago, Chile
| | - S Espinoza
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, P.O.BOX 70086, Santiago, Chile
| | - M F Hernandez
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, P.O.BOX 70086, Santiago, Chile.,Center for Genomics and Bioinformatics, Faculty of Science, Universidad Mayor, Camino la Piramide, 5750, Santiago, Chile
| | - J M Matamala
- Department of Neurological Sciences, Faculty of Medicine, University of Chile, Santiago, Chile.,Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Independencia, 1027, Santiago, Chile
| | - L Bargsted
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Independencia, 1027, Santiago, Chile
| | - S Matus
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Independencia, 1027, Santiago, Chile.,Fundación Ciencia & Vida, Zañartu 1482, 7780272, Santiago, Chile.,Neurounion Biomedical Foundation, 7780272, Santiago, Chile.,Center for Geroscience, Brain Health and Metabolism (GERO), Santiago, Chile
| | - D Rojas-Rivera
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, P.O.BOX 70086, Santiago, Chile.,VIB Center for Inflammation Research, Technologiepark 927, Zwijnaarde, 9052, Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Technologiepark 927, Zwijnaarde, 9052, Ghent, Belgium
| | - M J M Bertrand
- VIB Center for Inflammation Research, Technologiepark 927, Zwijnaarde, 9052, Ghent, Belgium.,Department of Biomedical Molecular Biology, Ghent University, Technologiepark 927, Zwijnaarde, 9052, Ghent, Belgium
| | - D B Medinas
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Independencia, 1027, Santiago, Chile.,Center for Geroscience, Brain Health and Metabolism (GERO), Santiago, Chile.,Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Independencia, 1027, Santiago, Chile
| | - C Hetz
- Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Independencia, 1027, Santiago, Chile.,Center for Geroscience, Brain Health and Metabolism (GERO), Santiago, Chile.,Buck Institute for Research on Aging, Novato, CA, 94945, USA.,Program of Cellular and Molecular Biology, Institute of Biomedical Sciences, University of Chile, Independencia, 1027, Santiago, Chile.,Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA, 02115, USA
| | - P A Manque
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, P.O.BOX 70086, Santiago, Chile. .,Center for Genomics and Bioinformatics, Faculty of Science, Universidad Mayor, Camino la Piramide, 5750, Santiago, Chile. .,Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, VA, 23298, USA.
| | - U Woehlbier
- Center for Integrative Biology, Faculty of Science, Universidad Mayor, Camino la Piramide 5750, P.O.BOX 70086, Santiago, Chile. .,Center for Genomics and Bioinformatics, Faculty of Science, Universidad Mayor, Camino la Piramide, 5750, Santiago, Chile.
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80
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Zheng YR, Zhang XN, Chen Z. Mitochondrial transport serves as a mitochondrial quality control strategy in axons: Implications for central nervous system disorders. CNS Neurosci Ther 2019; 25:876-886. [PMID: 30900394 PMCID: PMC6566064 DOI: 10.1111/cns.13122] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Revised: 03/02/2019] [Accepted: 03/05/2019] [Indexed: 12/13/2022] Open
Abstract
Axonal mitochondrial quality is essential for neuronal health and functions. Compromised mitochondrial quality, reflected by loss of membrane potential, collapse of ATP production, abnormal morphology, burst of reactive oxygen species generation, and impaired Ca2+ buffering capacity, can alter mitochondrial transport. Mitochondrial transport in turn maintains axonal mitochondrial homeostasis in several ways. Newly generated mitochondria are anterogradely transported along with axon from soma to replenish axonal mitochondrial pool, while damaged mitochondria undergo retrograde transport for repair or degradation. Besides, mitochondria are also arrested in axon to quarantine damages locally. Accumulating evidence suggests abnormal mitochondrial transport leads to mitochondrial dysfunction and axon degeneration in a variety of neurological and psychiatric disorders. Further investigations into the details of this process would help to extend our understanding of various neurological diseases and shed light on the corresponding therapies.
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Affiliation(s)
- Yan-Rong Zheng
- Institute of Pharmacology and Toxicology, NHC and CAMS Key Laboratory of Medical Neurobiology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Xiang-Nan Zhang
- Institute of Pharmacology and Toxicology, NHC and CAMS Key Laboratory of Medical Neurobiology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Zhong Chen
- Institute of Pharmacology and Toxicology, NHC and CAMS Key Laboratory of Medical Neurobiology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China.,Department of Neurology, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
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81
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Gonzalez Porras MA, Sieck GC, Mantilla CB. Impaired Autophagy in Motor Neurons: A Final Common Mechanism of Injury and Death. Physiology (Bethesda) 2019; 33:211-224. [PMID: 29638184 DOI: 10.1152/physiol.00008.2018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Autophagy is a cellular digestion process that contributes to cellular homeostasis and adaptation by the elimination of proteins and damaged organelles. Evidence suggests that dysregulation of autophagy plays a role in neurodegenerative diseases, including motor neuron disorders. Herein, we review emerging evidence indicating the roles of autophagy in physiological motor neuron processes and its function in specific compartments. Moreover, we discuss the involvement of autophagy in the pathogenesis of motor neuron diseases, including spinal cord injury and aging, and recent developments that offer promising therapeutic approaches to mitigate effects of dysregulated autophagy in health and disease.
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Affiliation(s)
| | - Gary C Sieck
- Department of Physiology & Biomedical Engineering, Mayo Clinic , Rochester, Minnesota.,Department of Anesthesiology and Perioperative Medicine, Mayo Clinic , Rochester, Minnesota
| | - Carlos B Mantilla
- Department of Physiology & Biomedical Engineering, Mayo Clinic , Rochester, Minnesota.,Department of Anesthesiology and Perioperative Medicine, Mayo Clinic , Rochester, Minnesota
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82
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Liang Y. Emerging Concepts and Functions of Autophagy as a Regulator of Synaptic Components and Plasticity. Cells 2019; 8:cells8010034. [PMID: 30634508 PMCID: PMC6357011 DOI: 10.3390/cells8010034] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 12/23/2018] [Accepted: 01/03/2019] [Indexed: 12/15/2022] Open
Abstract
Protein homeostasis (proteostasis) is crucial to the maintenance of neuronal integrity and function. As the contact sites between neurons, synapses rely heavily on precisely regulated protein-protein interactions to support synaptic transmission and plasticity processes. Autophagy is an effective degradative pathway that can digest cellular components and maintain cellular proteostasis. Perturbations of autophagy have been implicated in aging and neurodegeneration due to a failure to remove damaged proteins and defective organelles. Recent evidence has demonstrated that autophagosome formation is prominent at synaptic terminals and neuronal autophagy is regulated in a compartment-specific fashion. Moreover, synaptic components including synaptic proteins and vesicles, postsynaptic receptors and synaptic mitochondria are known to be degraded by autophagy, thereby contributing to the remodeling of synapses. Indeed, emerging studies indicate that modulation of autophagy may be required for different forms of synaptic plasticity and memory formation. In this review, I will discuss our current understanding of the important role of neuronal/synaptic autophagy in maintaining neuronal function by degrading synaptic components and try to propose a conceptual framework of how the degradation of synaptic components via autophagy might impact synaptic function and contribute to synaptic plasticity.
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Affiliation(s)
- YongTian Liang
- Neurogenetik, Institut für Biologie, Freie Universität Berlin, 14195 Berlin, Germany.
- NeuroCure, Cluster of Excellence, Charité Universitätsmedizin, 10117 Berlin, Germany.
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83
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Palomo GM, Granatiero V, Kawamata H, Konrad C, Kim M, Arreguin AJ, Zhao D, Milner TA, Manfredi G. Parkin is a disease modifier in the mutant SOD1 mouse model of ALS. EMBO Mol Med 2018; 10:e8888. [PMID: 30126943 PMCID: PMC6180298 DOI: 10.15252/emmm.201808888] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 07/26/2018] [Accepted: 07/27/2018] [Indexed: 12/14/2022] Open
Abstract
Mutant Cu/Zn superoxide dismutase (SOD1) causes mitochondrial alterations that contribute to motor neuron demise in amyotrophic lateral sclerosis (ALS). When mitochondria are damaged, cells activate mitochondria quality control (MQC) mechanisms leading to mitophagy. Here, we show that in the spinal cord of G93A mutant SOD1 transgenic mice (SOD1-G93A mice), the autophagy receptor p62 is recruited to mitochondria and mitophagy is activated. Furthermore, the mitochondrial ubiquitin ligase Parkin and mitochondrial dynamics proteins, such as Miro1, and Mfn2, which are ubiquitinated by Parkin, and the mitochondrial biogenesis regulator PGC1α are depleted. Unexpectedly, Parkin genetic ablation delays disease progression and prolongs survival in SOD1-G93A mice, as it slows down motor neuron loss and muscle denervation and attenuates the depletion of mitochondrial dynamics proteins and PGC1α. Our results indicate that Parkin is a disease modifier in ALS, because chronic Parkin-mediated MQC activation depletes mitochondrial dynamics-related proteins, inhibits mitochondrial biogenesis, and worsens mitochondrial dysfunction.
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Affiliation(s)
- Gloria M Palomo
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Veronica Granatiero
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Hibiki Kawamata
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Csaba Konrad
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Michelle Kim
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Andrea J Arreguin
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Dazhi Zhao
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
| | - Teresa A Milner
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
- Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY, USA
| | - Giovanni Manfredi
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY, USA
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84
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Activation of autophagy rescues synaptic and cognitive deficits in fragile X mice. Proc Natl Acad Sci U S A 2018; 115:E9707-E9716. [PMID: 30242133 DOI: 10.1073/pnas.1808247115] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Fragile X syndrome (FXS) is the most frequent form of heritable intellectual disability and autism. Fragile X (Fmr1-KO) mice exhibit aberrant dendritic spine structure, synaptic plasticity, and cognition. Autophagy is a catabolic process of programmed degradation and recycling of proteins and cellular components via the lysosomal pathway. However, a role for autophagy in the pathophysiology of FXS is, as yet, unclear. Here we show that autophagic flux, a functional readout of autophagy, and biochemical markers of autophagy are down-regulated in hippocampal neurons of fragile X mice. We further show that enhanced activity of mammalian target of rapamycin complex 1 (mTORC1) and translocation of Raptor, a defining component of mTORC1, to the lysosome are causally related to reduced autophagy. Activation of autophagy by delivery of shRNA to Raptor directly into the CA1 of living mice via the lentivirus expression system largely corrects aberrant spine structure, synaptic plasticity, and cognition in fragile X mice. Postsynaptic density protein (PSD-95) and activity-regulated cytoskeletal-associated protein (Arc/Arg3.1), proteins implicated in spine structure and synaptic plasticity, respectively, are elevated in neurons lacking fragile X mental retardation protein. Activation of autophagy corrects PSD-95 and Arc abundance, identifying a potential mechanism by which impaired autophagy is causally related to the fragile X phenotype and revealing a previously unappreciated role for autophagy in the synaptic and cognitive deficits associated with fragile X syndrome.
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85
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Cheng XT, Xie YX, Zhou B, Huang N, Farfel-Becker T, Sheng ZH. Characterization of LAMP1-labeled nondegradative lysosomal and endocytic compartments in neurons. J Cell Biol 2018; 217:3127-3139. [PMID: 29695488 PMCID: PMC6123004 DOI: 10.1083/jcb.201711083] [Citation(s) in RCA: 157] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 02/20/2018] [Accepted: 04/13/2018] [Indexed: 01/04/2023] Open
Abstract
Despite widespread distribution of LAMP1 and the heterogeneous nature of LAMP1-labeled compartments, LAMP1 is routinely used as a lysosomal marker, and LAMP1-positive organelles are often referred to as lysosomes. In this study, we use immunoelectron microscopy and confocal imaging to provide quantitative analysis of LAMP1 distribution in various autophagic and endolysosomal organelles in neurons. Our study demonstrates that a significant portion of LAMP1-labeled organelles do not contain detectable lysosomal hydrolases including cathepsins D and B and glucocerebrosidase. A bovine serum albumin-gold pulse-chase assay followed by ultrastructural analysis suggests a heterogeneity of degradative capacity in LAMP1-labeled endolysosomal organelles. Gradient fractionation displays differential distribution patterns of LAMP1/2 and cathepsins D/B in neurons. We further reveal that LAMP1 intensity in familial amyotrophic lateral sclerosis-linked motor neurons does not necessarily reflect lysosomal deficits in vivo. Our study suggests that labeling a set of lysosomal hydrolases combined with various endolysosomal markers would be more accurate than simply relying on LAMP1/2 staining to assess neuronal lysosome distribution, trafficking, and functionality under physiological and pathological conditions.
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Affiliation(s)
- Xiu-Tang Cheng
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - Yu-Xiang Xie
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - Bing Zhou
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - Ning Huang
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - Tamar Farfel-Becker
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - Zu-Hang Sheng
- Synaptic Function Section, The Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
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86
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Kiryu-Seo S, Kiyama H. Mitochondrial behavior during axon regeneration/degeneration in vivo. Neurosci Res 2018; 139:42-47. [PMID: 30179641 DOI: 10.1016/j.neures.2018.08.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 07/31/2018] [Accepted: 08/22/2018] [Indexed: 01/25/2023]
Abstract
Over the last decade, mitochondrial dynamics beyond function during axon regeneration/degeneration have received attention. Axons have an effective delivery system of mitochondria shuttling between soma and axonal terminals, due to their polarized structure. The proper axonal transport of mitochondria, coordinated with mitochondrial fission/fusion and clearance, is vital for supplying high power energy in injured axons. Many researchers have studied mitochondrial dynamics using in vitro cultured cells with significant progress reported. However, the in vitro culture system is missing a physiological environment including glial cells, immune cells, and endothelial cells, whose communications are indispensable to nerve regeneration/degeneration. In line with this, the understanding of mitochondrial behavior in injured axon in vivo is necessary for promoting the physiological understanding of damaged axons and the development of a therapeutic strategy. In this review, we focus on recent insights into in vivo mitochondrial dynamics during axonal regeneration/degeneration, and introduce the advances of mouse strains to visualize mitochondria in a neuron-specific or an injury-specific manner, which are extremely useful for nerve regeneration/degeneration studies.
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Affiliation(s)
- Sumiko Kiryu-Seo
- Department of Functional Anatomy and Neuroscience, Graduate School of Medicine, Nagoya University. 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
| | - Hiroshi Kiyama
- Department of Functional Anatomy and Neuroscience, Graduate School of Medicine, Nagoya University. 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan
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87
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Bojungikgi-tang Improves Muscle and Spinal Cord Function in an Amyotrophic Lateral Sclerosis Model. Mol Neurobiol 2018; 56:2394-2407. [PMID: 30030751 DOI: 10.1007/s12035-018-1236-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 07/10/2018] [Indexed: 12/13/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a motor neuron disease characterized by progressive motor function impairment, dysphagia, and respiratory failure. Owing to the complexity of its pathogenic mechanisms, an effective therapy for ALS is lacking. Herbal medicines with multiple targets have good efficacy and low adverse reactions for the treatment of neurodegenerative diseases. In this study, the effects of Bojungikgi-tang (BJIGT), an herbal medicine with eight component herbs, on muscle and spinal cord function were evaluated in an ALS animal model. Animals were randomly divided into three groups: a non-transgenic group (nTg, n = 24), a hSOD1G93A transgenic group (Tg, n = 24), and a hSOD1G93A transgenic group in which 8-week-old mice were orally administered BJIGT (1 mg/g) once daily for 6 weeks (Tg+BJIGT, n = 24). The effects of BJIGT were evaluated using a rotarod test, foot-printing, and survival analyses based on Kaplan-Meier survival curves. To determine the biological mechanism underlying the effects of BJIGT in hSOD1G93A mice, western blotting, transmission electron microscopy, and Bungarotoxin staining were used. BJIGT improved motor function and extended the survival duration of hSOD1G93A mice. In addition, BJIGT had protective effects, including anti-oxidative and anti-inflammatory effects, in both the spinal cord and muscle of hSOD1G93A mice. Our results demonstrated that BJIGT causes muscle atrophy and the denervation of neuromuscular junctions in the gastrocnemius of hSOD1G93A mice. The components of BJIGT may alleviate the symptoms of ALS via different mechanisms, and accordingly, BJIGT treatment may be an effective therapeutic approach.
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88
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Yamashita T, Kwak S. Cell death cascade and molecular therapy in ADAR2-deficient motor neurons of ALS. Neurosci Res 2018; 144:4-13. [PMID: 29944911 DOI: 10.1016/j.neures.2018.06.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Revised: 05/19/2018] [Accepted: 06/14/2018] [Indexed: 02/06/2023]
Abstract
TAR DNA-binding protein (TDP-43) pathology in the motor neurons is the most reliable pathological hallmark of amyotrophic lateral sclerosis (ALS), and motor neurons bearing TDP-43 pathology invariably exhibit failure in RNA editing at the GluA2 glutamine/arginine (Q/R) site due to down-regulation of adenosine deaminase acting on RNA 2 (ADAR2). Conditional ADAR2 knockout (AR2) mice display ALS-like phenotype, including progressive motor dysfunction due to loss of motor neurons. Motor neurons devoid of ADAR2 express Q/R site-unedited GluA2, and AMPA receptors with unedited GluA2 in their subunit assembly are abnormally permeable to Ca2+, which results in progressive neuronal death. Moreover, analysis of AR2 mice has demonstrated that exaggerated Ca2+ influx through the abnormal AMPA receptors overactivates calpain, a Ca2+-dependent protease, that cleaves TDP-43 into aggregation-prone fragments, which serve as seeds for TDP-43 pathology. Activated calpain also disrupts nucleo-cytoplasmic transport and gene expression by cleaving molecules involved in nucleocytoplasmic transport, including nucleoporins. These lines of evidence prompted us to develop molecular targeting therapy for ALS by normalization of disrupted intracellular environment due to ADAR2 down-regulation. In this review, we have summarized the work from our group on the cell death cascade in sporadic ALS and discussed a potential therapeutic strategy for ALS.
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Affiliation(s)
- Takenari Yamashita
- Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Shin Kwak
- Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan; Department of Neurology, Tokyo Medical University, 6-7-1, Nishishinjuku, Shinjuku-ku, Tokyo, 160-0023, Japan.
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89
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Lie PPY, Nixon RA. Lysosome trafficking and signaling in health and neurodegenerative diseases. Neurobiol Dis 2018; 122:94-105. [PMID: 29859318 DOI: 10.1016/j.nbd.2018.05.015] [Citation(s) in RCA: 173] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 04/27/2018] [Accepted: 05/29/2018] [Indexed: 12/20/2022] Open
Abstract
Lysosomes, single-membrane organelles defined by a uniquely strong acidic lumenal pH and high content of acid hydrolases, are the shared degradative compartments of the endocytic and autophagic pathways. These pathways, and especially lysosomes, are points of particular vulnerability in many neurodegenerative diseases. Beyond the role of lysosomes in substrate degradation, new findings have ascribed to lysosomes the leading role in sensing and responding to cellular nutrients, growth factors and cellular stress. This review aims to integrate recent concepts of basic lysosome biology and pathobiology as a basis for understanding neurodegenerative disease pathogenesis. Here, we discuss the newly recognized signaling functions of lysosomes and specific aspects of lysosome biology in neurons while re-visiting the classical defining criteria for lysosomes and the importance of preserving strict definitions. Our discussion emphasizes dynein-mediated axonal transport of maturing degradative organelles, with further consideration of their roles in synaptic function. We finally examine how distinctive underlying disturbances of lysosomes in various neurodegenerative diseases result in unique patterns of auto/endolysosomal mistrafficking. The rapidly emerging understanding of lysosomal trafficking and disruptions in lysosome signaling is providing valuable clues to new targets for disease-modifying therapies.
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Affiliation(s)
- Pearl P Y Lie
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University Langone Medical Center, New York, NY 10016, USA.
| | - Ralph A Nixon
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University Langone Medical Center, New York, NY 10016, USA; Department of Cell Biology, New York University Langone Medical Center, New York, NY 10016, USA; NYU Neuroscience Institute, New York University Langone Medical Center, New York, NY 10016, USA
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90
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Diogo CV, Yambire KF, Fernández Mosquera L, Branco F T, Raimundo N. Mitochondrial adventures at the organelle society. Biochem Biophys Res Commun 2018; 500:87-93. [PMID: 28456629 PMCID: PMC5930832 DOI: 10.1016/j.bbrc.2017.04.124] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2017] [Accepted: 04/23/2017] [Indexed: 01/16/2023]
Abstract
Mitochondria are constantly communicating with the rest of the cell. Defects in mitochondria underlie severe pathologies, whose mechanisms remain poorly understood. It is becoming increasingly evident that mitochondrial malfunction resonates in other organelles, perturbing their function and their biogenesis. In this manuscript, we review the current knowledge on the cross-talk between mitochondria and other organelles, particularly lysosomes, peroxisomes and the endoplasmic reticulum. Several organelle interactions are mediated by transcriptional programs, and other signaling mechanisms are likely mediating organelle dysfunction downstream of mitochondrial impairments. Many of these organelle crosstalk pathways are likely to have a role in pathological processes.
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Affiliation(s)
- Cátia V Diogo
- Universitätsmedizin Göttingen, Institute fur Zellbiochemie, Humboldtallee 23, room 01.423, 37073 Göttingen, Germany
| | - King Faisal Yambire
- Universitätsmedizin Göttingen, Institute fur Zellbiochemie, Humboldtallee 23, room 01.423, 37073 Göttingen, Germany; International Max-Planck Research School in Neuroscience, Göttingen, Germany
| | - Lorena Fernández Mosquera
- Universitätsmedizin Göttingen, Institute fur Zellbiochemie, Humboldtallee 23, room 01.423, 37073 Göttingen, Germany
| | - Tiago Branco F
- Universitätsmedizin Göttingen, Institute fur Zellbiochemie, Humboldtallee 23, room 01.423, 37073 Göttingen, Germany
| | - Nuno Raimundo
- Universitätsmedizin Göttingen, Institute fur Zellbiochemie, Humboldtallee 23, room 01.423, 37073 Göttingen, Germany.
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91
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Moruno-Manchon JF, Uzor NE, Ambati CR, Shetty V, Putluri N, Jagannath C, McCullough LD, Tsvetkov AS. Sphingosine kinase 1-associated autophagy differs between neurons and astrocytes. Cell Death Dis 2018; 9:521. [PMID: 29743513 PMCID: PMC5943283 DOI: 10.1038/s41419-018-0599-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 04/05/2018] [Accepted: 04/12/2018] [Indexed: 02/07/2023]
Abstract
Autophagy is a degradative pathway for removing aggregated proteins, damaged organelles, and parasites. Evidence indicates that autophagic pathways differ between cell types. In neurons, autophagy plays a homeostatic role, compared to a survival mechanism employed by starving non-neuronal cells. We investigated if sphingosine kinase 1 (SK1)-associated autophagy differs between two symbiotic brain cell types—neurons and astrocytes. SK1 synthesizes sphingosine-1-phosphate, which regulates autophagy in non-neuronal cells and in neurons. We found that benzoxazine autophagy inducers upregulate SK1 and neuroprotective autophagy in neurons, but not in astrocytes. Starvation enhances SK1-associated autophagy in astrocytes, but not in neurons. In astrocytes, SK1 is cytoprotective and promotes the degradation of an autophagy substrate, mutant huntingtin, the protein that causes Huntington’s disease. Overexpressed SK1 is unexpectedly toxic to neurons, and its toxicity localizes to the neuronal soma, demonstrating an intricate relationship between the localization of SK1’s activity and neurotoxicity. Our results underscore the importance of cell type-specific autophagic differences in any efforts to target autophagy therapeutically.
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Affiliation(s)
- Jose F Moruno-Manchon
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, Houston, TX, 77030, USA
| | - Ndidi-Ese Uzor
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, Houston, TX, 77030, USA.,The University of Texas Graduate School of Biomedical Sciences, Houston, TX, 77030, USA
| | - Chandrashekar R Ambati
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Vivekananda Shetty
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Nagireddy Putluri
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Chinnaswamy Jagannath
- Department of Pathology and Laboratory Medicine, The University of Texas McGovern Medical School, Houston, TX, 77030, USA
| | - Louise D McCullough
- The University of Texas Graduate School of Biomedical Sciences, Houston, TX, 77030, USA.,Department of Neurology, The University of Texas McGovern Medical School at Houston, Houston, TX, 77030, USA
| | - Andrey S Tsvetkov
- Department of Neurobiology and Anatomy, The University of Texas McGovern Medical School, Houston, TX, 77030, USA. .,The University of Texas Graduate School of Biomedical Sciences, Houston, TX, 77030, USA. .,UT Health Consortium on Aging, The University of Texas McGovern Medical School, Houston, TX, 77030, USA.
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92
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Tammineni P, Jeong YY, Feng T, Aikal D, Cai Q. Impaired axonal retrograde trafficking of the retromer complex augments lysosomal deficits in Alzheimer's disease neurons. Hum Mol Genet 2018; 26:4352-4366. [PMID: 28973312 DOI: 10.1093/hmg/ddx321] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Accepted: 08/09/2017] [Indexed: 01/13/2023] Open
Abstract
Lysosomal proteolysis is essential for the quality control of intracellular components and the maintenance of cellular homeostasis. Lysosomal alterations have been implicated as one of the main cellular defects contributing to the onset and progression of Alzheimer's disease (AD). However, the mechanism underlying lysosomal deficits in AD remains poorly understood. Here, we reveal that lysosomal deficits are attributed to retromer dysfunction induced by altered retromer trafficking in the axon of AD-related mutant human amyloid precursor protein (hAPP) transgenic (Tg) mouse neurons. We demonstrate that retrograde transport of retromer is impaired, leading to its significant reduction in the soma and abnormal retention within late endosomes in distal axons of mutant hAPP neurons. Therefore, retromer-mediated endosome-to-Golgi retrieval of cation-independent mannose-6-phosphate receptors (CI-MPR) in the soma is disrupted in mutant hAPP neurons, causing defects in lysosome biogenesis. Such defects result in protease deficiency in lysosomes and impaired lysosomal proteolysis, as evidenced by aberrant accumulation of sequestered substrates within lysosomes. Intriguingly, enhancement of retrograde transport in mutant hAPP neurons facilitates the trafficking of axonal retromer toward the soma and thus enhances protease transport to lysosomes, thereby restoring lysosomal proteolytic activity. Taken together, our study provides new insights into the regulation of retromer trafficking through retrograde axonal transport to fulfil its function in promoting lysosome biogenesis in the soma, suggesting a potential approach for rescuing lysosomal proteolysis deficits in AD.
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Affiliation(s)
- Prasad Tammineni
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Yu Young Jeong
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Tuancheng Feng
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Daniyal Aikal
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
| | - Qian Cai
- Department of Cell Biology and Neuroscience, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
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93
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Abstract
In recent years, the role of autophagy in the pathogenesis of most neurodegenerative diseases has transitioned into a limbo of protective or detrimental effects. Genetic evidence indicates that mutations in autophagy-regulatory genes can result in the occurrence of amyotrophic lateral sclerosis (ALS), suggesting a physiological role of the pathway to motoneuron function. However, experimental manipulation of autophagy in ALS models led to conflicting results depending on the intervention strategy and the disease model used. A recent work by the Maniatis group systematically explored the role of cell-specific autophagy in motoneurons at different disease stages, revealing surprising and unexpected findings. Autophagy activity at early stages may contribute to maintaining the structure and function of neuromuscular junctions, whereas at later steps of the disease it has a pathogenic activity possibly involving cell-nonautonomous mechanisms related to glial activation. This new study adds a new layer of complexity in the field, suggesting an intricate interplay between proteostasis alterations, the time-differential function of autophagy in neurons, and muscle innervation in ALS.
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Affiliation(s)
- Vicente Valenzuela
- a Biomedical Neuroscience Institute (BNI), Faculty of Medicine , University of Chile , Santiago , Chile.,b Center for Geroscience , Brain Health and Metabolism (GERO) , Santiago , Chile.,c Program of Cellular and Molecular Biology , Institute of Biomedical Sciences, University of Chile , Santiago , Chile
| | - Melissa Nassif
- d Center for Integrative Biology (CIB), Faculty of Sciences , Universidad Mayor , Santiago , Chile
| | - Claudio Hetz
- a Biomedical Neuroscience Institute (BNI), Faculty of Medicine , University of Chile , Santiago , Chile.,b Center for Geroscience , Brain Health and Metabolism (GERO) , Santiago , Chile.,c Program of Cellular and Molecular Biology , Institute of Biomedical Sciences, University of Chile , Santiago , Chile.,e Buck Institute for Research on Aging , Novato , CA , USA.,f Department of Immunology and Infectious Diseases , Harvard School of Public Health , Boston MA , USA
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94
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Liao EH, Gray L, Tsurudome K, El-Mounzer W, Elazzouzi F, Baim C, Farzin S, Calderon MR, Kauwe G, Haghighi AP. Kinesin Khc-73/KIF13B modulates retrograde BMP signaling by influencing endosomal dynamics at the Drosophila neuromuscular junction. PLoS Genet 2018; 14:e1007184. [PMID: 29373576 PMCID: PMC5802963 DOI: 10.1371/journal.pgen.1007184] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 02/07/2018] [Accepted: 01/03/2018] [Indexed: 11/18/2022] Open
Abstract
Retrograde signaling is essential for neuronal growth, function and survival; however, we know little about how signaling endosomes might be directed from synaptic terminals onto retrograde axonal pathways. We have identified Khc-73, a plus-end directed microtubule motor protein, as a regulator of sorting of endosomes in Drosophila larval motor neurons. The number of synaptic boutons and the amount of neurotransmitter release at the Khc-73 mutant larval neuromuscular junction (NMJ) are normal, but we find a significant decrease in the number of presynaptic release sites. This defect in Khc-73 mutant larvae can be genetically enhanced by a partial genetic loss of Bone Morphogenic Protein (BMP) signaling or suppressed by activation of BMP signaling in motoneurons. Consistently, activation of BMP signaling that normally enhances the accumulation of phosphorylated form of BMP transcription factor Mad in the nuclei, can be suppressed by genetic removal of Khc-73. Using a number of assays including live imaging in larval motor neurons, we show that loss of Khc-73 curbs the ability of retrograde-bound endosomes to leave the synaptic area and join the retrograde axonal pathway. Our findings identify Khc-73 as a regulator of endosomal traffic at the synapse and modulator of retrograde BMP signaling in motoneurons.
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Affiliation(s)
- Edward H. Liao
- Buck Institute for Research on Aging, Novato, CA, United States of America
| | - Lindsay Gray
- Buck Institute for Research on Aging, Novato, CA, United States of America
| | - Kazuya Tsurudome
- Buck Institute for Research on Aging, Novato, CA, United States of America
| | | | - Fatima Elazzouzi
- Department of Physiology, McGill University, Montreal, QC, Canada
| | - Christopher Baim
- Department of Physiology, McGill University, Montreal, QC, Canada
| | - Sarah Farzin
- Department of Physiology, McGill University, Montreal, QC, Canada
| | - Mario R. Calderon
- Buck Institute for Research on Aging, Novato, CA, United States of America
- Department of Physiology, McGill University, Montreal, QC, Canada
| | - Grant Kauwe
- Buck Institute for Research on Aging, Novato, CA, United States of America
| | - A. Pejmun Haghighi
- Buck Institute for Research on Aging, Novato, CA, United States of America
- Department of Physiology, McGill University, Montreal, QC, Canada
- * E-mail:
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95
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Deng Z, Sheehan P, Chen S, Yue Z. Is amyotrophic lateral sclerosis/frontotemporal dementia an autophagy disease? Mol Neurodegener 2017; 12:90. [PMID: 29282133 PMCID: PMC5746010 DOI: 10.1186/s13024-017-0232-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 12/07/2017] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are neurodegenerative disorders that share genetic risk factors and pathological hallmarks. Intriguingly, these shared factors result in a high rate of comorbidity of these diseases in patients. Intracellular protein aggregates are a common pathological hallmark of both diseases. Emerging evidence suggests that impaired RNA processing and disrupted protein homeostasis are two major pathogenic pathways for these diseases. Indeed, recent evidence from genetic and cellular studies of the etiology and pathogenesis of ALS-FTD has suggested that defects in autophagy may underlie various aspects of these diseases. In this review, we discuss the link between genetic mutations, autophagy dysfunction, and the pathogenesis of ALS-FTD. Although dysfunction in a variety of cellular pathways can lead to these diseases, we provide evidence that ALS-FTD is, in many cases, an autophagy disease.
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Affiliation(s)
- Zhiqiang Deng
- Brain center, Zhongnan Hospital, Wuhan University, Wuhan, Hubei, 430071, China.,Taihe Hospital, Hubei University of Medicine, Shiyan, Hubei, 442000, China.,Department of Neurology, The Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, 10029, USA
| | - Patricia Sheehan
- Department of Neurology, The Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, 10029, USA
| | - Shi Chen
- Brain center, Zhongnan Hospital, Wuhan University, Wuhan, Hubei, 430071, China. .,Taihe Hospital, Hubei University of Medicine, Shiyan, Hubei, 442000, China.
| | - Zhenyu Yue
- Department of Neurology, The Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, 10029, USA.
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96
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Kulkarni VV, Maday S. Compartment-specific dynamics and functions of autophagy in neurons. Dev Neurobiol 2017; 78:298-310. [PMID: 29197160 DOI: 10.1002/dneu.22562] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 11/13/2017] [Accepted: 11/16/2017] [Indexed: 02/06/2023]
Abstract
Autophagy is a lysosomal degradation pathway that is critical to maintaining neuronal homeostasis and viability. Autophagy sequesters damaged and aged cellular components from the intracellular environment, and shuttles these diverse macromolecules to lysosomes for destruction. This active surveillance of the quality of the cytoplasm and organelles is essential in neurons to sustain their long-term functionality and viability. Indeed, defective autophagy is linked to neurodevelopmental abnormalities and neurodegeneration in mammals. Here, we review the mechanisms of autophagy in neurons and functional roles for autophagy in neuronal homeostasis. We focus on the compartment-specific dynamics of autophagy in neurons, and how autophagy might perform non-canonical functions critical for neurons. We suggest the existence of multiple populations of autophagosomes with compartment-specific functions important for neural activity and function. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 298-310, 2018.
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Affiliation(s)
- Vineet Vinay Kulkarni
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, 19104
| | - Sandra Maday
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, 19104
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97
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Distinct roles for motor neuron autophagy early and late in the SOD1 G93A mouse model of ALS. Proc Natl Acad Sci U S A 2017; 114:E8294-E8303. [PMID: 28904095 DOI: 10.1073/pnas.1704294114] [Citation(s) in RCA: 138] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Mutations in autophagy genes can cause familial and sporadic amyotrophic lateral sclerosis (ALS). However, the role of autophagy in ALS pathogenesis is poorly understood, in part due to the lack of cell type-specific manipulations of this pathway in animal models. Using a mouse model of ALS expressing mutant superoxide dismutase 1 (SOD1G93A), we show that motor neurons form large autophagosomes containing ubiquitinated aggregates early in disease progression. To investigate whether this response is protective or detrimental, we generated mice in which the critical autophagy gene Atg7 was specifically disrupted in motor neurons (Atg7 cKO). Atg7 cKO mice were viable but exhibited structural and functional defects at a subset of vulnerable neuromuscular junctions. By crossing Atg7 cKO mice to the SOD1G93A mouse model, we found that autophagy inhibition accelerated early neuromuscular denervation of the tibialis anterior muscle and the onset of hindlimb tremor. Surprisingly, however, lifespan was extended in Atg7 cKO; SOD1G93A double-mutant mice. Autophagy inhibition did not prevent motor neuron cell death, but it reduced glial inflammation and blocked activation of the stress-related transcription factor c-Jun in spinal interneurons. We conclude that motor neuron autophagy is required to maintain neuromuscular innervation early in disease but eventually acts in a non-cell-autonomous manner to promote disease progression.
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98
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Rogers RS, Tungtur S, Tanaka T, Nadeau LL, Badawi Y, Wang H, Ni HM, Ding WX, Nishimune H. Impaired Mitophagy Plays a Role in Denervation of Neuromuscular Junctions in ALS Mice. Front Neurosci 2017; 11:473. [PMID: 28890682 PMCID: PMC5575151 DOI: 10.3389/fnins.2017.00473] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Accepted: 08/10/2017] [Indexed: 12/11/2022] Open
Abstract
Motor neurons in amyotrophic lateral sclerosis (ALS) patients and animal models show degeneration from the nerve terminal, known as dying-back neuropathy. To investigate the mechanism underlying this neuropathy, we analyzed the neuromuscular junctions (NMJs) and motor neuron cell bodies in SOD1G93A mice using electron microscopy. NMJs of SOD1G93A mice exhibited significantly higher numbers of autophagosomes and degenerated mitochondria compared to wild-type controls. Mitophagosomes were identified in the NMJ presynaptic terminals of wild-type mice and SOD1G93A mice. However, the number of mitophagosomes did not increase significantly in SOD1G93A NMJs indicating a defect in mitophagy, the autophagic process to degrade mitochondria. Consistent with this, proteins essential for mitophagy, p62/SQSTM1, Bnip3, Pink1, and Parkin were down-regulated in motor neurons in SOD1G93A mice. Importantly, SQSTM1 is one of the genes mutated in familial ALS patients. We evaluated the effect of impaired mitophagy on motor neurons by analyzing the double knockout mice of Pink1 and Parkin, two genes responsible for sensing depolarized mitochondria and delivering degenerated mitochondria to mitophagosomes. The double knockout mice exhibited NMJ degeneration, including axon swelling and NMJ fragmentation at 4 months of age. These phenotypes were rarely observed in wild-type control mice of the same age. The protein level of ATP synthase β subunit increased in the NMJ presynaptic terminals, suggesting the accumulation of mitochondria at NMJs of the double knockout mice. Importantly, NMJ denervation was observed in the double knockout mice. These data suggest that the reduced mitophagy function in motor neurons of SOD1G93A mice is one of the mechanisms causing degeneration of ALS NMJs.
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Affiliation(s)
- Robert S Rogers
- Department of Anatomy and Cell Biology, University of Kansas School of MedicineKansas City, KS, United States
| | - Sudheer Tungtur
- Department of Anatomy and Cell Biology, University of Kansas School of MedicineKansas City, KS, United States
| | - Tomohiro Tanaka
- Department of Anatomy and Cell Biology, University of Kansas School of MedicineKansas City, KS, United States
| | - Lisa L Nadeau
- Department of Anatomy and Cell Biology, University of Kansas School of MedicineKansas City, KS, United States
| | - Yomna Badawi
- Department of Anatomy and Cell Biology, University of Kansas School of MedicineKansas City, KS, United States
| | - Hua Wang
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas School of MedicineKansas City, KS, United States
| | - Hong-Min Ni
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas School of MedicineKansas City, KS, United States
| | - Wen-Xing Ding
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas School of MedicineKansas City, KS, United States
| | - Hiroshi Nishimune
- Department of Anatomy and Cell Biology, University of Kansas School of MedicineKansas City, KS, United States
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99
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Ramesh N, Pandey UB. Autophagy Dysregulation in ALS: When Protein Aggregates Get Out of Hand. Front Mol Neurosci 2017; 10:263. [PMID: 28878620 PMCID: PMC5572252 DOI: 10.3389/fnmol.2017.00263] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 08/03/2017] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder that results from the loss of upper and lower motor neurons. One of the key pathological hallmarks in diseased neurons is the mislocalization of disease-associated proteins and the formation of cytoplasmic aggregates of these proteins and their interactors due to defective protein quality control. This apparent imbalance in the cellular protein homeostasis could be a crucial factor in causing motor neuron death in the later stages of the disease in patients. Autophagy is a major protein degradation pathway that is involved in the clearance of protein aggregates and damaged organelles. Abnormalities in autophagy have been observed in numerous neurodegenerative disorders, including ALS. In this review, we discuss the contribution of autophagy dysfunction in various in vitro and in vivo models of ALS. Furthermore, we examine the crosstalk between autophagy and other cellular stresses implicated in ALS pathogenesis and the therapeutic implications of regulating autophagy in ALS.
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Affiliation(s)
- Nandini Ramesh
- Department of Human Genetics, University of Pittsburgh Graduate School of Public HealthPittsburgh, PA, United States.,Division of Child Neurology, Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical CenterPittsburgh, PA, United States
| | - Udai Bhan Pandey
- Department of Human Genetics, University of Pittsburgh Graduate School of Public HealthPittsburgh, PA, United States.,Division of Child Neurology, Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh Medical CenterPittsburgh, PA, United States.,Department of Neurology, University of Pittsburgh School of MedicinePittsburgh, PA, United States
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100
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Khalil B, Liévens JC. Mitochondrial quality control in amyotrophic lateral sclerosis: towards a common pathway? Neural Regen Res 2017; 12:1052-1061. [PMID: 28852382 PMCID: PMC5558479 DOI: 10.4103/1673-5374.211179] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/27/2017] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder characterized by loss of upper and lower motor neurons. Different mechanisms contribute to the disease initiation and progression, including mitochondrial dysfunction which has been proposed to be a central determinant in ALS pathogenesis. Indeed, while mitochondrial defects have been mainly described in ALS-linked SOD1 mutants, it is now well established that mitochondria become also dysfunctional in other ALS conditions. In such context, the mitochondrial quality control system allows to restore normal functioning of mitochondria and to prevent cell death, by both eliminating and replacing damaged mitochondrial components or by degrading the entire organelle through mitophagy. Recent evidence shows that ALS-related genes interfere with the mitochondrial quality control system. This review highlights how ineffective mitochondrial quality control may render motor neurons defenseless towards the accumulating mitochondrial damage in ALS.
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Affiliation(s)
- Bilal Khalil
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, FL, USA
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