1
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McGuinness HY, Gu W, Shi Y, Kobe B, Ve T. SARM1-Dependent Axon Degeneration: Nucleotide Signaling, Neurodegenerative Disorders, Toxicity, and Therapeutic Opportunities. Neuroscientist 2024; 30:473-492. [PMID: 37002660 PMCID: PMC11282687 DOI: 10.1177/10738584231162508] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Abstract
Axons are an essential component of the nervous system, and axon degeneration is an early feature of many neurodegenerative disorders. The NAD+ metabolome plays an essential role in regulating axonal integrity. Axonal levels of NAD+ and its precursor NMN are controlled in large part by the NAD+ synthesizing survival factor NMNAT2 and the pro-neurodegenerative NADase SARM1, whose activation triggers axon destruction. SARM1 has emerged as a promising axon-specific target for therapeutic intervention, and its function, regulation, structure, and role in neurodegenerative diseases have been extensively characterized in recent years. In this review, we first introduce the key molecular players involved in the SARM1-dependent axon degeneration program. Next, we summarize recent major advances in our understanding of how SARM1 is kept inactive in healthy neurons and how it becomes activated in injured or diseased neurons, which has involved important insights from structural biology. Finally, we discuss the role of SARM1 in neurodegenerative disorders and environmental neurotoxicity and its potential as a therapeutic target.
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Affiliation(s)
- Helen Y. McGuinness
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Saint Lucia, Australia
| | - Weixi Gu
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Saint Lucia, Australia
| | - Yun Shi
- Institute for Glycomics, Griffith University, Gold Coast, Australia
| | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Saint Lucia, Australia
| | - Thomas Ve
- Institute for Glycomics, Griffith University, Gold Coast, Australia
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2
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Loreto A, Merlini E, Coleman MP. Programmed axon death: a promising target for treating retinal and optic nerve disorders. Eye (Lond) 2024; 38:1802-1809. [PMID: 38538779 PMCID: PMC11226669 DOI: 10.1038/s41433-024-03025-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 02/13/2024] [Accepted: 03/08/2024] [Indexed: 07/07/2024] Open
Abstract
Programmed axon death is a druggable pathway of axon degeneration that has garnered considerable interest from pharmaceutical companies as a promising therapeutic target for various neurodegenerative disorders. In this review, we highlight mechanisms through which this pathway is activated in the retina and optic nerve, and discuss its potential significance for developing therapies for eye disorders and beyond. At the core of programmed axon death are two enzymes, NMNAT2 and SARM1, with pivotal roles in NAD metabolism. Extensive preclinical data in disease models consistently demonstrate remarkable, and in some instances, complete and enduring neuroprotection when this mechanism is targeted. Findings from animal studies are now being substantiated by genetic human data, propelling the field rapidly toward clinical translation. As we approach the clinical phase, the selection of suitable disorders for initial clinical trials targeting programmed axon death becomes crucial for their success. We delve into the multifaceted roles of programmed axon death and NAD metabolism in retinal and optic nerve disorders. We discuss the role of SARM1 beyond axon degeneration, including its potential involvement in neuronal soma death and photoreceptor degeneration. We also discuss genetic human data and environmental triggers of programmed axon death. Lastly, we touch upon potential therapeutic approaches targeting NMNATs and SARM1, as well as the nicotinamide trials for glaucoma. The extensive literature linking programmed axon death to eye disorders, along with the eye's suitability for drug delivery and visual assessments, makes retinal and optic nerve disorders strong contenders for early clinical trials targeting programmed axon death.
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Affiliation(s)
- Andrea Loreto
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Forvie Site, Robinson Way, Cambridge, UK.
- School of Medical Sciences and Save Sight Institute, Charles Perkins Centre, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.
| | - Elisa Merlini
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Forvie Site, Robinson Way, Cambridge, UK
| | - Michael P Coleman
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Forvie Site, Robinson Way, Cambridge, UK.
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3
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Dingwall CB, Sasaki Y, Strickland A, Summers DW, Bloom AJ, DiAntonio A, Milbrandt J. Suppressing phagocyte activation by overexpressing the phosphatidylserine lipase ABHD12 preserves sarmopathic nerves. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.20.599919. [PMID: 38979309 PMCID: PMC11230269 DOI: 10.1101/2024.06.20.599919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Programmed axon degeneration (AxD) is a key feature of many neurodegenerative diseases. In healthy axons, the axon survival factor NMNAT2 inhibits SARM1, the central executioner of AxD, preventing it from initiating the rapid local NAD+ depletion and metabolic catastrophe that precipitates axon destruction. Because these components of the AxD pathway act within neurons, it was also assumed that the timetable of AxD was set strictly by a cell-intrinsic mechanism independent of neuron-extrinsic processes later activated by axon fragmentation. However, using a rare human disease model of neuropathy caused by hypomorphic NMNAT2 mutations and chronic SARM1 activation (sarmopathy), we demonstrated that neuronal SARM1 can initiate macrophage-mediated axon elimination long before stressed-but-viable axons would otherwise succumb to cell-intrinsic metabolic failure. Investigating potential SARM1-dependent signals that mediate macrophage recognition and/or engulfment of stressed-but-viable axons, we found that chronic SARM1 activation triggers axonal blebbing and dysregulation of phosphatidylserine (PS), a potent phagocyte immunomodulatory molecule. Neuronal expression of the phosphatidylserine lipase ABDH12 suppresses nerve macrophage activation, preserves motor axon integrity, and rescues motor function in this chronic sarmopathy model. We conclude that PS dysregulation is an early SARM1-dependent axonal stress signal, and that blockade of phagocytic recognition and engulfment of stressed-but-viable axons could be an attractive therapeutic target for management of neurological disorders involving SARM1 activation.
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4
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Geisler S. Augustus Waller's foresight realized: SARM1 in peripheral neuropathies. Curr Opin Neurobiol 2024; 87:102884. [PMID: 38852438 DOI: 10.1016/j.conb.2024.102884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Revised: 05/16/2024] [Accepted: 05/17/2024] [Indexed: 06/11/2024]
Abstract
Peripheral neuropathy is a common neurodegenerative condition characterized by numbness, tingling, pain, and weakness that frequently starts in the distal limbs. Arising from multiple etiologies, many peripheral neuropathies exhibit a slowly progressive course due to axon degeneration for which no effective treatments exist. During the past decade, numerous crucial insights into mechanisms of axon degeneration in peripheral neuropathies emerged from experiments involving nerve-cutting procedures, revealing the central role of the SARM1 axon degeneration pathway in both. Here I review commonalities and differences in the role of SARM1 after nerve cut and in several acquired and inherited peripheral neuropathies. This new knowledge now paves the way for the development of therapeutics that directly address root causes of various kinds of neuropathies.
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Affiliation(s)
- Stefanie Geisler
- Department of Neurology, Washington University School of Medicine in St. Louis, 660S. Euclid Ave, Box 8111, St. Louis, MO 63110, USA.
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5
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Song M, Kang K, Wang S, Zhang C, Zhao X, Song F. Elevated intracellular Ca 2+ functions downstream of mitodysfunction to induce Wallerian-like degeneration and necroptosis in organophosphorus-induced delayed neuropathy. Toxicology 2024; 504:153812. [PMID: 38653376 DOI: 10.1016/j.tox.2024.153812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 04/06/2024] [Accepted: 04/19/2024] [Indexed: 04/25/2024]
Abstract
Neurotoxic organophosphorus compounds can induce a type of delayed neuropathy in humans and sensitive animals, known as organophosphorus-induced delayed neuropathy (OPIDN). OPIDN is characterized by axonal degeneration akin to Wallerian-like degeneration, which is thought to be caused by increased intra-axonal Ca2+ concentrations. This study was designed to investigate that deregulated cytosolic Ca2+ may function downstream of mitodysfunction in activating Wallerian-like degeneration and necroptosis in OPIDN. Adult hens were administrated a single dosage of 750 mg/kg tri-ortho-cresyl phosphate (TOCP), and then sacrificed at 1 day, 5 day, 10 day and 21 day post-exposure, respectively. Sciatic nerves and spinal cords were examined for pathological changes and proteins expression related to Wallerian-like degeneration and necroptosis. In vitro experiments using differentiated neuro-2a (N2a) cells were conducted to investigate the relationship among mitochondrial dysfunction, Ca2+ influx, axonal degeneration, and necroptosis. The cells were co-administered with the Ca2+-chelator BAPTA-AM, the TRPA1 channel inhibitor HC030031, the RIPK1 inhibitor Necrostatin-1, and the mitochondrial-targeted antioxidant MitoQ along with TOCP. Results demonstrated an increase in cytosolic calcium concentration and key proteins associated with Wallerian degeneration and necroptosis in both in vivo and in vitro models after TOCP exposure. Moreover, co-administration with BATPA-AM or HC030031 significantly attenuated the loss of NMNAT2 and STMN2 in N2a cells, as well as the upregulation of SARM1, RIPK1 and p-MLKL. In contrast, Necrostatin-1 treatment only inhibited the TOCP-induced elevation of p-MLKL. Notably, pharmacological protection of mitochondrial function with MitoQ effectively alleviated the increase in intracellular Ca2+ following TOCP and mitigated axonal degeneration and necroptosis in N2a cells, supporting mitochondrial dysfunction as an upstream event of the intracellular Ca2+ imbalance and neuronal damage in OPIDN. These findings suggest that mitochondrial dysfunction post-TOCP intoxication leads to an elevated intracellular Ca2+ concentration, which plays a pivotal role in the initiation and development of OPIDN through inducing SARM1-mediated axonal degeneration and activating the necroptotic signaling pathway.
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Affiliation(s)
- Mingxue Song
- Department of Toxicology and Nutrition, School of Public Health, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan, Shandong 250012, PR China
| | - Kang Kang
- Qingdao Municipal Center for Disease Control & Prevention, Qingdao, Shandong 266033, PR China
| | - Shuai Wang
- Department of Toxicology and Nutrition, School of Public Health, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan, Shandong 250012, PR China
| | - Cuiqin Zhang
- Department of Toxicology and Nutrition, School of Public Health, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan, Shandong 250012, PR China
| | - Xiulan Zhao
- Department of Toxicology and Nutrition, School of Public Health, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan, Shandong 250012, PR China
| | - Fuyong Song
- Department of Toxicology and Nutrition, School of Public Health, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan, Shandong 250012, PR China.
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Yang S, Niou ZX, Enriquez A, LaMar J, Huang JY, Ling K, Jafar-Nejad P, Gilley J, Coleman MP, Tennessen JM, Rangaraju V, Lu HC. NMNAT2 supports vesicular glycolysis via NAD homeostasis to fuel fast axonal transport. Mol Neurodegener 2024; 19:13. [PMID: 38282024 PMCID: PMC10823734 DOI: 10.1186/s13024-023-00690-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 11/28/2023] [Indexed: 01/30/2024] Open
Abstract
BACKGROUND Bioenergetic maladaptations and axonopathy are often found in the early stages of neurodegeneration. Nicotinamide adenine dinucleotide (NAD), an essential cofactor for energy metabolism, is mainly synthesized by Nicotinamide mononucleotide adenylyl transferase 2 (NMNAT2) in CNS neurons. NMNAT2 mRNA levels are reduced in the brains of Alzheimer's, Parkinson's, and Huntington's disease. Here we addressed whether NMNAT2 is required for axonal health of cortical glutamatergic neurons, whose long-projecting axons are often vulnerable in neurodegenerative conditions. We also tested if NMNAT2 maintains axonal health by ensuring axonal ATP levels for axonal transport, critical for axonal function. METHODS We generated mouse and cultured neuron models to determine the impact of NMNAT2 loss from cortical glutamatergic neurons on axonal transport, energetic metabolism, and morphological integrity. In addition, we determined if exogenous NAD supplementation or inhibiting a NAD hydrolase, sterile alpha and TIR motif-containing protein 1 (SARM1), prevented axonal deficits caused by NMNAT2 loss. This study used a combination of techniques, including genetics, molecular biology, immunohistochemistry, biochemistry, fluorescent time-lapse imaging, live imaging with optical sensors, and anti-sense oligos. RESULTS We provide in vivo evidence that NMNAT2 in glutamatergic neurons is required for axonal survival. Using in vivo and in vitro studies, we demonstrate that NMNAT2 maintains the NAD-redox potential to provide "on-board" ATP via glycolysis to vesicular cargos in distal axons. Exogenous NAD+ supplementation to NMNAT2 KO neurons restores glycolysis and resumes fast axonal transport. Finally, we demonstrate both in vitro and in vivo that reducing the activity of SARM1, an NAD degradation enzyme, can reduce axonal transport deficits and suppress axon degeneration in NMNAT2 KO neurons. CONCLUSION NMNAT2 ensures axonal health by maintaining NAD redox potential in distal axons to ensure efficient vesicular glycolysis required for fast axonal transport.
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Affiliation(s)
- Sen Yang
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
| | - Zhen-Xian Niou
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA
| | - Andrea Enriquez
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA
| | - Jacob LaMar
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
- Present address: Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, 33458, USA
| | - Jui-Yen Huang
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
| | - Karen Ling
- Neuroscience Drug Discovery, Ionis Pharmaceuticals, Inc., 2855, Gazelle Court, Carlsbad, CA, 92010, USA
| | - Paymaan Jafar-Nejad
- Neuroscience Drug Discovery, Ionis Pharmaceuticals, Inc., 2855, Gazelle Court, Carlsbad, CA, 92010, USA
| | - Jonathan Gilley
- Department of Clinical Neuroscience, Cambridge University, Cambridge, UK
| | - Michael P Coleman
- Department of Clinical Neuroscience, Cambridge University, Cambridge, UK
| | - Jason M Tennessen
- Department of Biology, Indiana University, Bloomington, IN, 47405, USA
| | - Vidhya Rangaraju
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, 33458, USA
| | - Hui-Chen Lu
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA.
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA.
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA.
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7
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Chandrasekaran K, Najimi N, Sagi AR, Yarlagadda S, Salimian M, Arvas MI, Hedayat AF, Kevas Y, Kadakia A, Kristian T, Russell JW. NAD + Precursors Reverse Experimental Diabetic Neuropathy in Mice. Int J Mol Sci 2024; 25:1102. [PMID: 38256175 PMCID: PMC10816262 DOI: 10.3390/ijms25021102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 01/05/2024] [Accepted: 01/13/2024] [Indexed: 01/24/2024] Open
Abstract
Abnormal NAD+ signaling has been implicated in axonal degeneration in diabetic peripheral neuropathy (DPN). We hypothesized that supplementing NAD+ precursors could alleviate DPN symptoms through increasing the NAD+ levels and activating the sirtuin-1 (SIRT1) protein. To test this, we exposed cultured Dorsal Root Ganglion neurons (DRGs) to Nicotinamide Riboside (NR) or Nicotinamide Mononucleotide (NMN), which increased the levels of NAD+, the SIRT1 protein, and the deacetylation activity that is associated with increased neurite growth. A SIRT1 inhibitor blocked the neurite growth induced via NR or NMN. We then induced neuropathy in C57BL6 mice with streptozotocin (STZ) or a high fat diet (HFD) and administered NR or NMN for two months. Both the STZ and HFD mice developed neuropathy, which was reversed through the NR or NMN administration: sensory function improved, nerve conduction velocities normalized, and intraepidermal nerve fibers were restored. The NAD+ levels and SIRT1 activity were reduced in the DRGs from diabetic mice but were preserved with the NR or NMN treatment. We also tested the effect of NR or NMN administration in mice that overexpress the SIRT1 protein in neurons (nSIRT1 OE) and found no additional benefit from the addition of the drug. These findings suggest that supplementing with NAD+ precursors or activating SIRT1 may be a promising treatment for DPN.
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Affiliation(s)
- Krish Chandrasekaran
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (N.N.); (S.Y.); (M.I.A.); (A.F.H.); (Y.K.); (A.K.)
| | - Neda Najimi
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (N.N.); (S.Y.); (M.I.A.); (A.F.H.); (Y.K.); (A.K.)
| | - Avinash R. Sagi
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (N.N.); (S.Y.); (M.I.A.); (A.F.H.); (Y.K.); (A.K.)
| | - Sushuma Yarlagadda
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (N.N.); (S.Y.); (M.I.A.); (A.F.H.); (Y.K.); (A.K.)
| | - Mohammad Salimian
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (N.N.); (S.Y.); (M.I.A.); (A.F.H.); (Y.K.); (A.K.)
| | - Muhammed Ikbal Arvas
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (N.N.); (S.Y.); (M.I.A.); (A.F.H.); (Y.K.); (A.K.)
| | - Ahmad F. Hedayat
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (N.N.); (S.Y.); (M.I.A.); (A.F.H.); (Y.K.); (A.K.)
| | - Yanni Kevas
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (N.N.); (S.Y.); (M.I.A.); (A.F.H.); (Y.K.); (A.K.)
| | - Anand Kadakia
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (N.N.); (S.Y.); (M.I.A.); (A.F.H.); (Y.K.); (A.K.)
| | - Tibor Kristian
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
- Veterans Affairs Medical Center, Baltimore, MD 21201, USA
| | - James W. Russell
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (N.N.); (S.Y.); (M.I.A.); (A.F.H.); (Y.K.); (A.K.)
- Veterans Affairs Medical Center, Baltimore, MD 21201, USA
- CAMC Institute for Academic Medicine, 415 Morris Street Suite 300, Charleston, WV 25301, USA
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8
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Funakoshi M, Araki T. Mechanism of initiation and regulation of axonal degeneration with special reference to NMNATs and Sarm1. Neurosci Res 2023; 197:3-8. [PMID: 34767875 DOI: 10.1016/j.neures.2021.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 11/01/2021] [Indexed: 10/19/2022]
Abstract
Axonal degeneration is observed in a variety of contexts in both the central and peripheral nervous systems. Pathological signaling to regulate the progression of axonal degeneration has long been studied using Wallerian degeneration, the prototypical axonal degradation observed after injury, as a representative model. Understanding metabolism of nicotinamide adenine dinucleotide (NAD+) and the functional regulation of Sarm1 has generated great progress in this field, but there are a number of remaining questions. Here, in this short review, we describe our current understanding of the axonal degeneration mechanism, with special reference to the biology related to wlds mice and Sarm1. Furthermore, variations of axonal degeneration initiation are discussed in order to address the remaining questions needed for mechanistic clarification.
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Affiliation(s)
- Masabumi Funakoshi
- Department of Peripheral Nervous System Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1 Ogawa-Higashi, Kodaira, Tokyo, 187-8502, Japan
| | - Toshiyuki Araki
- Department of Peripheral Nervous System Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1 Ogawa-Higashi, Kodaira, Tokyo, 187-8502, Japan.
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9
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Jain A, Casanova D, Padilla AV, Paniagua Bojorges A, Kotla S, Ko KA, Samanthapudi VSK, Chau K, Nguyen MTH, Wen J, Hernandez Gonzalez SL, Rodgers SP, Olmsted-Davis EA, Hamilton DJ, Reyes-Gibby C, Yeung SCJ, Cooke JP, Herrmann J, Chini EN, Xu X, Yusuf SW, Yoshimoto M, Lorenzi PL, Hobbs B, Krishnan S, Koutroumpakis E, Palaskas NL, Wang G, Deswal A, Lin SH, Abe JI, Le NT. Premature senescence and cardiovascular disease following cancer treatments: mechanistic insights. Front Cardiovasc Med 2023; 10:1212174. [PMID: 37781317 PMCID: PMC10540075 DOI: 10.3389/fcvm.2023.1212174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 08/03/2023] [Indexed: 10/03/2023] Open
Abstract
Cardiovascular disease (CVD) is a leading cause of morbidity and mortality, especially among the aging population. The "response-to-injury" model proposed by Dr. Russell Ross in 1999 emphasizes inflammation as a critical factor in atherosclerosis development, with atherosclerotic plaques forming due to endothelial cell (EC) injury, followed by myeloid cell adhesion and invasion into the blood vessel walls. Recent evidence indicates that cancer and its treatments can lead to long-term complications, including CVD. Cellular senescence, a hallmark of aging, is implicated in CVD pathogenesis, particularly in cancer survivors. However, the precise mechanisms linking premature senescence to CVD in cancer survivors remain poorly understood. This article aims to provide mechanistic insights into this association and propose future directions to better comprehend this complex interplay.
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Affiliation(s)
- Ashita Jain
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Diego Casanova
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | | | | | - Sivareddy Kotla
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Kyung Ae Ko
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | | | - Khanh Chau
- Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX, United States
| | - Minh T. H. Nguyen
- Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX, United States
| | - Jake Wen
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | | | - Shaefali P. Rodgers
- Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX, United States
| | | | - Dale J. Hamilton
- Department of Medicine, Center for Bioenergetics, Houston Methodist Research Institute, Houston, TX, United States
| | - Cielito Reyes-Gibby
- Department of Emergency Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Sai-Ching J. Yeung
- Department of Emergency Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - John P. Cooke
- Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX, United States
| | - Joerg Herrmann
- Cardio Oncology Clinic, Division of Preventive Cardiology, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, United States
| | - Eduardo N. Chini
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Jacksonville, FL, United States
| | - Xiaolei Xu
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, United States
| | - Syed Wamique Yusuf
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Momoko Yoshimoto
- Center for Stem Cell & Regenerative Medicine, The University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Philip L. Lorenzi
- Department of Bioinformatics and Computational Biology, Division of VP Research, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Brain Hobbs
- Department of Population Health, The University of Texas at Austin, Austin, TX, United States
| | - Sunil Krishnan
- Department of Neurosurgery, The University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Efstratios Koutroumpakis
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Nicolas L. Palaskas
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Guangyu Wang
- Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX, United States
| | - Anita Deswal
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Steven H. Lin
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Jun-ichi Abe
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Nhat-Tu Le
- Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX, United States
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10
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Tribble JR, Hui F, Quintero H, El Hajji S, Bell K, Di Polo A, Williams PA. Neuroprotection in glaucoma: Mechanisms beyond intraocular pressure lowering. Mol Aspects Med 2023; 92:101193. [PMID: 37331129 DOI: 10.1016/j.mam.2023.101193] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/25/2023] [Accepted: 06/04/2023] [Indexed: 06/20/2023]
Abstract
Glaucoma is a common, complex, multifactorial neurodegenerative disease characterized by progressive dysfunction and then loss of retinal ganglion cells, the output neurons of the retina. Glaucoma is the most common cause of irreversible blindness and affects ∼80 million people worldwide with many more undiagnosed. The major risk factors for glaucoma are genetics, age, and elevated intraocular pressure. Current strategies only target intraocular pressure management and do not directly target the neurodegenerative processes occurring at the level of the retinal ganglion cell. Despite strategies to manage intraocular pressure, as many as 40% of glaucoma patients progress to blindness in at least one eye during their lifetime. As such, neuroprotective strategies that target the retinal ganglion cell and these neurodegenerative processes directly are of great therapeutic need. This review will cover the recent advances from basic biology to on-going clinical trials for neuroprotection in glaucoma covering degenerative mechanisms, metabolism, insulin signaling, mTOR, axon transport, apoptosis, autophagy, and neuroinflammation. With an increased understanding of both the basic and clinical mechanisms of the disease, we are closer than ever to a neuroprotective strategy for glaucoma.
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Affiliation(s)
- James R Tribble
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Flora Hui
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia; Department of Optometry & Vision Sciences, The University of Melbourne, Melbourne, Australia
| | - Heberto Quintero
- Department of Neuroscience, University of Montreal, Montreal, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Canada
| | - Sana El Hajji
- Department of Neuroscience, University of Montreal, Montreal, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Canada
| | - Katharina Bell
- NHMRC Clinical Trials Centre, University of Sydney, Australia; Eye ACP Duke-NUS, Singapore
| | - Adriana Di Polo
- Department of Neuroscience, University of Montreal, Montreal, Canada; Neuroscience Division, Centre de recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montreal, Canada
| | - Pete A Williams
- Department of Clinical Neuroscience, Division of Eye and Vision, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden.
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11
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Smith G, Sweeney ST, O’Kane CJ, Prokop A. How neurons maintain their axons long-term: an integrated view of axon biology and pathology. Front Neurosci 2023; 17:1236815. [PMID: 37564364 PMCID: PMC10410161 DOI: 10.3389/fnins.2023.1236815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 07/06/2023] [Indexed: 08/12/2023] Open
Abstract
Axons are processes of neurons, up to a metre long, that form the essential biological cables wiring nervous systems. They must survive, often far away from their cell bodies and up to a century in humans. This requires self-sufficient cell biology including structural proteins, organelles, and membrane trafficking, metabolic, signalling, translational, chaperone, and degradation machinery-all maintaining the homeostasis of energy, lipids, proteins, and signalling networks including reactive oxygen species and calcium. Axon maintenance also involves specialised cytoskeleton including the cortical actin-spectrin corset, and bundles of microtubules that provide the highways for motor-driven transport of components and organelles for virtually all the above-mentioned processes. Here, we aim to provide a conceptual overview of key aspects of axon biology and physiology, and the homeostatic networks they form. This homeostasis can be derailed, causing axonopathies through processes of ageing, trauma, poisoning, inflammation or genetic mutations. To illustrate which malfunctions of organelles or cell biological processes can lead to axonopathies, we focus on axonopathy-linked subcellular defects caused by genetic mutations. Based on these descriptions and backed up by our comprehensive data mining of genes linked to neural disorders, we describe the 'dependency cycle of local axon homeostasis' as an integrative model to explain why very different causes can trigger very similar axonopathies, providing new ideas that can drive the quest for strategies able to battle these devastating diseases.
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Affiliation(s)
- Gaynor Smith
- Cardiff University, School of Medicine, College of Biomedical and Life Sciences, Cardiff, United Kingdom
| | - Sean T. Sweeney
- Department of Biology, University of York and York Biomedical Research Institute, York, United Kingdom
| | - Cahir J. O’Kane
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Andreas Prokop
- Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biology, The University of Manchester, Manchester, United Kingdom
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12
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Guss EJ, Akbergenova Y, Cunningham KL, Littleton JT. Loss of the extracellular matrix protein Perlecan disrupts axonal and synaptic stability during Drosophila development. eLife 2023; 12:RP88273. [PMID: 37368474 PMCID: PMC10328508 DOI: 10.7554/elife.88273] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2023] Open
Abstract
Heparan sulfate proteoglycans (HSPGs) form essential components of the extracellular matrix (ECM) and basement membrane (BM) and have both structural and signaling roles. Perlecan is a secreted ECM-localized HSPG that contributes to tissue integrity and cell-cell communication. Although a core component of the ECM, the role of Perlecan in neuronal structure and function is less understood. Here, we identify a role for Drosophila Perlecan in the maintenance of larval motoneuron axonal and synaptic stability. Loss of Perlecan causes alterations in the axonal cytoskeleton, followed by axonal breakage and synaptic retraction of neuromuscular junctions. These phenotypes are not prevented by blocking Wallerian degeneration and are independent of Perlecan's role in Wingless signaling. Expression of Perlecan solely in motoneurons cannot rescue synaptic retraction phenotypes. Similarly, removing Perlecan specifically from neurons, glia, or muscle does not cause synaptic retraction, indicating the protein is secreted from multiple cell types and functions non-cell autonomously. Within the peripheral nervous system, Perlecan predominantly localizes to the neural lamella, a specialized ECM surrounding nerve bundles. Indeed, the neural lamella is disrupted in the absence of Perlecan, with axons occasionally exiting their usual boundary in the nerve bundle. In addition, entire nerve bundles degenerate in a temporally coordinated manner across individual hemi-segments throughout larval development. These observations indicate disruption of neural lamella ECM function triggers axonal destabilization and synaptic retraction of motoneurons, revealing a role for Perlecan in axonal and synaptic integrity during nervous system development.
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Affiliation(s)
- Ellen J Guss
- The Picower Institute for Learning and Memory, Department of Biology, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Yulia Akbergenova
- The Picower Institute for Learning and Memory, Department of Biology, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - Karen L Cunningham
- The Picower Institute for Learning and Memory, Department of Biology, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
| | - J Troy Littleton
- The Picower Institute for Learning and Memory, Department of Biology, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, United States
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13
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Yang S, Niou ZX, Enriquez A, LaMar J, Huang JY, Ling K, Jafar-Nejad P, Gilley J, Coleman MP, Tennessen JM, Rangaraju V, Lu HC. NMNAT2 supports vesicular glycolysis via NAD homeostasis to fuel fast axonal transport. RESEARCH SQUARE 2023:rs.3.rs-2859584. [PMID: 37292715 PMCID: PMC10246254 DOI: 10.21203/rs.3.rs-2859584/v1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Background Bioenergetic maladaptations and axonopathy are often found in the early stages of neurodegeneration. Nicotinamide adenine dinucleotide (NAD), an essential cofactor for energy metabolism, is mainly synthesized by Nicotinamide mononucleotide adenylyl transferase 2 (NMNAT2) in CNS neurons. NMNAT2 mRNA levels are reduced in the brains of Alzheimer's, Parkinson's, and Huntington's disease. Here we addressed whether NMNAT2 is required for axonal health of cortical glutamatergic neurons, whose long-projecting axons are often vulnerable in neurodegenerative conditions. We also tested if NMNAT2 maintains axonal health by ensuring axonal ATP levels for axonal transport, critical for axonal function. Methods We generated mouse and cultured neuron models to determine the impact of NMNAT2 loss from cortical glutamatergic neurons on axonal transport, energetic metabolism, and morphological integrity. In addition, we determined if exogenous NAD supplementation or inhibiting a NAD hydrolase, sterile alpha and TIR motif-containing protein 1 (SARM1), prevented axonal deficits caused by NMNAT2 loss. This study used a combination of genetics, molecular biology, immunohistochemistry, biochemistry, fluorescent time-lapse imaging, live imaging with optical sensors, and anti-sense oligos. Results We provide in vivo evidence that NMNAT2 in glutamatergic neurons is required for axonal survival. Using in vivo and in vitro studies, we demonstrate that NMNAT2 maintains the NAD-redox potential to provide "on-board" ATP via glycolysis to vesicular cargos in distal axons. Exogenous NAD+ supplementation to NMNAT2 KO neurons restores glycolysis and resumes fast axonal transport. Finally, we demonstrate both in vitro and in vivo that reducing the activity of SARM1, an NAD degradation enzyme, can reduce axonal transport deficits and suppress axon degeneration in NMNAT2 KO neurons. Conclusion NMNAT2 ensures axonal health by maintaining NAD redox potential in distal axons to ensure efficient vesicular glycolysis required for fast axonal transport.
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14
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Waddell J, Khatoon R, Kristian T. Cellular and Mitochondrial NAD Homeostasis in Health and Disease. Cells 2023; 12:1329. [PMID: 37174729 PMCID: PMC10177113 DOI: 10.3390/cells12091329] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 04/26/2023] [Accepted: 05/04/2023] [Indexed: 05/15/2023] Open
Abstract
The mitochondrion has a unique position among other cellular organelles due to its dynamic properties and symbiotic nature, which is reflected in an active exchange of metabolites and cofactors between the rest of the intracellular compartments. The mitochondrial energy metabolism is greatly dependent on nicotinamide adenine dinucleotide (NAD) as a cofactor that is essential for both the activity of respiratory and TCA cycle enzymes. The NAD level is determined by the rate of NAD synthesis, the activity of NAD-consuming enzymes, and the exchange rate between the individual subcellular compartments. In this review, we discuss the NAD synthesis pathways, the NAD degradation enzymes, and NAD subcellular localization, as well as NAD transport mechanisms with a focus on mitochondria. Finally, the effect of the pathologic depletion of mitochondrial NAD pools on mitochondrial proteins' post-translational modifications and its role in neurodegeneration will be reviewed. Understanding the physiological constraints and mechanisms of NAD maintenance and the exchange between subcellular compartments is critical given NAD's broad effects and roles in health and disease.
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Affiliation(s)
- Jaylyn Waddell
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
| | - Rehana Khatoon
- Department of Anesthesiology and the Center for Shock, Trauma and Anesthesiology Research (S.T.A.R.), University of Maryland School of Medicine, Baltimore, MD 21201, USA;
| | - Tibor Kristian
- Department of Anesthesiology and the Center for Shock, Trauma and Anesthesiology Research (S.T.A.R.), University of Maryland School of Medicine, Baltimore, MD 21201, USA;
- Veterans Affairs Maryland Health Center System, 10 North Greene Street, Baltimore, MD 21201, USA
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15
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Li W, Gao M, Hu C, Chen X, Zhou Y. NMNAT2: An important metabolic enzyme affecting the disease progression. Biomed Pharmacother 2023; 158:114143. [PMID: 36528916 DOI: 10.1016/j.biopha.2022.114143] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 12/13/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Nicotinamide mononucleotide adenylyltransferase 2 (NMNAT2) is an evolutionarily conserved nicotinamide adenine dinucleotide (NAD+) synthase located in the cytoplasm and Golgi apparatus. NMNAT2 has an important role in neurodegenerative diseases, malignant tumors, and other diseases that seriously endanger human health. NMNAT2 exerts a neuroprotective function through its NAD synthase activity and chaperone function. Among them, the NMNAT2-NAD+-Sterile alpha and Toll/interleukin-1 receptor motif-containing 1 (SARM1) axis is closely related to Wallerian degeneration. Physical injury or pathological stimulation will cause a decrease in NMNAT2, which activates SARM1, leading to axonal degeneration and the occurrence of amyotrophic lateral sclerosis (ALS), Alzheimer's disease, peripheral neuropathy, and other neurodegenerative diseases. In addition, NMNAT2 exerts a cancer-promoting role in solid tumors, including colorectal cancer, lung cancer, ovarian cancer, and glioma, and is closely related to tumor occurrence and development. This paper reviews the chromosomal and subcellular localization of NMNAT2 and its basic biological functions. We also summarize the NMNAT2-related signal transduction pathway and the role of NMNAT2 in diseases. We aimed to provide a new perspective to comprehensively understand the relationship between NMNAT2 and its associated diseases.
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Affiliation(s)
- Wentao Li
- NHC Key Laboratory of Carcinogenesis, Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, China; Cancer Research Institute, Basic School of Medicine, Central South University, Changsha, Hunan 410078, China
| | - Mengxiang Gao
- NHC Key Laboratory of Carcinogenesis, Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, China; Cancer Research Institute, Basic School of Medicine, Central South University, Changsha, Hunan 410078, China
| | - Chunhui Hu
- Teaching and Research Section of Clinical Nursing, Xiangya Hospital of Central South University, Changsha, Hunan 410013, China
| | - Xiuwen Chen
- Teaching and Research Section of Clinical Nursing, Xiangya Hospital of Central South University, Changsha, Hunan 410013, China.
| | - Yanhong Zhou
- NHC Key Laboratory of Carcinogenesis, Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, China; Cancer Research Institute, Basic School of Medicine, Central South University, Changsha, Hunan 410078, China.
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16
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Wang S, Zhang Y, Lou J, Yong H, Shan S, Liu Z, Song M, Zhang C, Kou R, Liu Z, Yu W, Zhao X, Song F. The therapeutic potential of berberine chloride against SARM1-dependent axon degeneration in acrylamide-induced neuropathy. Phytother Res 2023; 37:77-88. [PMID: 36054436 DOI: 10.1002/ptr.7594] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2022] [Revised: 07/11/2022] [Accepted: 08/06/2022] [Indexed: 01/19/2023]
Abstract
Chronic acrylamide (ACR) intoxication causes typical pathology of axon degeneration. Moreover, sterile-α and toll/interleukin 1 receptor motif-containing protein 1 (SARM1), the central executioner of the programmed axonal destruction process under various insults, is up-regulated in ACR neuropathy. However, it remains unclear whether inhibitors targeting SARM1 are effective or not. Among all the pharmacological antagonists, berberine chloride (BBE), a natural phytochemical and the first identified non-competitive inhibitor of SARM1, attracts tremendous attention. Here, we observed the protection of 100 μM BBE against ACR-induced neurites injury (2 mM ACR, 24 hr) in vitro, and further evaluated the neuroprotective effect of BBE (100 mg/kg p.o. three times a week for 4 weeks) in ACR-intoxicated rats (40 mg/kg i.p. three times a week for 4 weeks). The expression of SARM1 was also detected. BBE intervention significantly inhibited the overexpression of SARM1, ameliorated axonal degeneration, alleviated pathological changes in the sciatic nerve and spinal cord, and improved neurobehavioral symptoms in ACR-poisoned rats. Thus, BBE exhibits a strong neuroprotective effect against the SARM1-dependent axon destruction in ACR neuropathy. Meanwhile, our study underscores the need for appropriate inhibitor selection in diverse situations that would benefit from blocking the SARM1-dependent axonal destruction pathway.
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Affiliation(s)
- Shuai Wang
- Department of Toxicology and Nutrition, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Yifan Zhang
- Department of Toxicology and Nutrition, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Jianwei Lou
- Department of Neurology, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Hui Yong
- Department of Toxicology and Nutrition, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Shulin Shan
- Department of Toxicology and Nutrition, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Zhidan Liu
- Department of Toxicology and Nutrition, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Mingxue Song
- Department of Toxicology and Nutrition, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Cuiqin Zhang
- Department of Toxicology and Nutrition, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China.,School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Ruirui Kou
- Department of Toxicology and Nutrition, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China.,School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Zhaoxiong Liu
- Department of Toxicology and Nutrition, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Wenhao Yu
- School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China.,Department of Biostatistics, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Xiulan Zhao
- Department of Toxicology and Nutrition, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China.,School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Fuyong Song
- Department of Toxicology and Nutrition, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
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17
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Lépine S, Castellanos-Montiel MJ, Durcan TM. TDP-43 dysregulation and neuromuscular junction disruption in amyotrophic lateral sclerosis. Transl Neurodegener 2022; 11:56. [PMID: 36575535 PMCID: PMC9793560 DOI: 10.1186/s40035-022-00331-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 11/29/2022] [Indexed: 12/28/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a disease characterized by upper and lower motor neuron (MN) loss with a signature feature of cytoplasmic aggregates containing TDP-43, which are detected in nearly all patients. Mutations in the gene that encodes TDP-43 (TARBDP) are known to result in both familial and sporadic ALS. In ALS, disruption of neuromuscular junctions (NMJs) constitutes a critical event in disease pathogenesis, leading to denervation atrophy, motor impairments and disability. Morphological defects and impaired synaptic transmission at NMJs have been reported in several TDP-43 animal models and in vitro, linking TDP-43 dysregulation to the loss of NMJ integrity in ALS. Through the lens of the dying-back and dying-forward hypotheses of ALS, this review discusses the roles of TDP-43 related to synaptic function, with a focus on the potential molecular mechanisms occurring within MNs, skeletal muscles and glial cells that may contribute to NMJ disruption in ALS.
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Affiliation(s)
- Sarah Lépine
- grid.14709.3b0000 0004 1936 8649The Neuro’s Early Drug Discovery Unit (EDDU), Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, 3801 University Street, Montreal, QC H3A 2B4 Canada ,grid.14709.3b0000 0004 1936 8649Faculty of Medicine and Health Sciences, McGill University, 3605 De La Montagne, Montreal, QC H3G 2M1 Canada
| | - Maria José Castellanos-Montiel
- grid.14709.3b0000 0004 1936 8649The Neuro’s Early Drug Discovery Unit (EDDU), Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, 3801 University Street, Montreal, QC H3A 2B4 Canada
| | - Thomas Martin Durcan
- grid.14709.3b0000 0004 1936 8649The Neuro’s Early Drug Discovery Unit (EDDU), Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, 3801 University Street, Montreal, QC H3A 2B4 Canada
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18
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Autophagy protein ULK1 interacts with and regulates SARM1 during axonal injury. Proc Natl Acad Sci U S A 2022; 119:e2203824119. [PMID: 36375051 PMCID: PMC9704737 DOI: 10.1073/pnas.2203824119] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Autophagy is a cellular catabolic pathway generally thought to be neuroprotective. However, autophagy and in particular its upstream regulator, the ULK1 kinase, can also promote axonal degeneration. We examined the role and the mechanisms of autophagy in axonal degeneration using a mouse model of contusive spinal cord injury (SCI). Consistent with activation of autophagy during axonal degeneration following SCI, autophagosome marker LC3, ULK1 kinase, and ULK1 target, phospho-ATG13, accumulated in the axonal bulbs and injured axons. SARM1, a TIR NADase with a pivotal role in axonal degeneration, colocalized with ULK1 within 1 h after SCI, suggesting possible interaction between autophagy and SARM1-mediated axonal degeneration. In our in vitro experiments, inhibition of autophagy, including Ulk1 knockdown and ULK1 inhibitor, attenuated neurite fragmentation and reduced accumulation of SARM1 puncta in neurites of primary cortical neurons subjected to glutamate excitotoxicity. Immunoprecipitation data demonstrated that ULK1 physically interacted with SARM1 in vitro and in vivo and that SAM domains of SARM1 were necessary for ULK1-SARM1 complex formation. Consistent with a role in regulation of axonal degeneration, in primary cortical neurons ULK1-SARM1 interaction increased upon neurite damage. Supporting a role for autophagy and ULK1 in regulation of SARM1 in axonal degeneration in vivo, axonal ULK1 activation and accumulation of SARM1 were both decreased after SCI in Becn1+/- autophagy hypomorph mice compared to wild-type (WT) controls. These findings suggest a regulatory crosstalk between autophagy and axonal degeneration pathways, which is mediated through ULK1-SARM1 interaction and contributes to the ability of SARM1 to accumulate in injured axons.
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19
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Feldman HC, Merlini E, Guijas C, DeMeester KE, Njomen E, Kozina EM, Yokoyama M, Vinogradova E, Reardon HT, Melillo B, Schreiber SL, Loreto A, Blankman JL, Cravatt BF. Selective inhibitors of SARM1 targeting an allosteric cysteine in the autoregulatory ARM domain. Proc Natl Acad Sci U S A 2022; 119:e2208457119. [PMID: 35994671 PMCID: PMC9436332 DOI: 10.1073/pnas.2208457119] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 07/25/2022] [Indexed: 12/23/2022] Open
Abstract
The nicotinamide adenine dinucleotide hydrolase (NADase) sterile alpha toll/interleukin receptor motif containing-1 (SARM1) acts as a central executioner of programmed axon death and is a possible therapeutic target for neurodegenerative disorders. While orthosteric inhibitors of SARM1 have been described, this multidomain enzyme is also subject to intricate forms of autoregulation, suggesting the potential for allosteric modes of inhibition. Previous studies have identified multiple cysteine residues that support SARM1 activation and catalysis, but which of these cysteines, if any, might be selectively targetable by electrophilic small molecules remains unknown. Here, we describe the chemical proteomic discovery of a series of tryptoline acrylamides that site-specifically and stereoselectively modify cysteine-311 (C311) in the noncatalytic, autoregulatory armadillo repeat (ARM) domain of SARM1. These covalent compounds inhibit the NADase activity of WT-SARM1, but not C311A or C311S SARM1 mutants, show a high degree of proteome-wide selectivity for SARM1_C311 and stereoselectively block vincristine- and vacor-induced neurite degeneration in primary rodent dorsal root ganglion neurons. Our findings describe selective, covalent inhibitors of SARM1 targeting an allosteric cysteine, pointing to a potentially attractive therapeutic strategy for axon degeneration-dependent forms of neurological disease.
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Affiliation(s)
| | - Elisa Merlini
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0PY, United Kingdom
| | - Carlos Guijas
- Lundbeck La Jolla Research Center Inc, San Diego, CA 92121
| | | | - Evert Njomen
- Department of Chemistry, Scripps Research, La Jolla, CA 92037
| | - Ellen M Kozina
- Lundbeck La Jolla Research Center Inc, San Diego, CA 92121
| | - Minoru Yokoyama
- Department of Chemistry, Scripps Research, La Jolla, CA 92037
| | | | | | - Bruno Melillo
- Department of Chemistry, Scripps Research, La Jolla, CA 92037
- Chemical Biology and Therapeutics Science Program, Broad Institute, Cambridge, MA 02138
| | - Stuart L Schreiber
- Chemical Biology and Therapeutics Science Program, Broad Institute, Cambridge, MA 02138
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138
| | - Andrea Loreto
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0PY, United Kingdom
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20
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Ademi M, Yang X, Coleman MP, Gilley J. Natural variants of human SARM1 cause both intrinsic and dominant loss-of-function influencing axon survival. Sci Rep 2022; 12:13846. [PMID: 35974060 PMCID: PMC9381744 DOI: 10.1038/s41598-022-18052-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 08/04/2022] [Indexed: 11/08/2022] Open
Abstract
SARM1 is a central executioner of programmed axon death, and this role requires intrinsic NAD(P)ase or related enzyme activity. A complete absence of SARM1 robustly blocks axon degeneration in mice, but even a partial depletion confers meaningful protection. Since axon loss contributes substantially to the onset and progression of multiple neurodegenerative disorders, lower inherent SARM1 activity is expected to reduce disease susceptibility in some situations. We, therefore, investigated whether there are naturally occurring SARM1 alleles within the human population that encode SARM1 variants with loss-of-function. Out of the 18 natural SARM1 coding variants we selected as candidates, we found that 10 display loss-of-function in three complimentary assays: they fail to robustly deplete NAD in transfected HEK 293T cells; they lack constitutive and NMN-induced NADase activity; and they fail to promote axon degeneration in primary neuronal cultures. Two of these variants are also able to block axon degeneration in primary culture neurons in the presence of endogenous, wild-type SARM1, indicative of dominant loss-of-function. These results demonstrate that SARM1 loss-of-function variants occur naturally in the human population, and we propose that carriers of these alleles will have different degrees of reduced susceptibility to various neurological conditions.
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Affiliation(s)
- Mirlinda Ademi
- Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Forvie Site, Robinson Way, Cambridge, CB2 0PY, UK
| | - Xiuna Yang
- Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Forvie Site, Robinson Way, Cambridge, CB2 0PY, UK
| | - Michael P Coleman
- Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Forvie Site, Robinson Way, Cambridge, CB2 0PY, UK.
| | - Jonathan Gilley
- Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Forvie Site, Robinson Way, Cambridge, CB2 0PY, UK.
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21
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Dissanayake KN, Redman RR, Mackenzie H, Eddleston M, Ribchester RR. "Calcium bombs" as harbingers of synaptic pathology and their mitigation by magnesium at murine neuromuscular junctions. Front Mol Neurosci 2022; 15:937974. [PMID: 35959105 PMCID: PMC9361872 DOI: 10.3389/fnmol.2022.937974] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 07/04/2022] [Indexed: 12/24/2022] Open
Abstract
Excitotoxicity is thought to be an important factor in the onset and progression of amyotrophic lateral sclerosis (ALS). Evidence from human and animal studies also indicates that early signs of ALS include degeneration of motor nerve terminals at neuromuscular junctions (NMJs), before degeneration of motor neuron cell bodies. Here we used a model of excitotoxicity at NMJs in isolated mouse muscle, utilizing the organophosphorus (OP) compound omethoate, which inhibits acetylcholinesterase activity. Acute exposure to omethoate (100 μM) induced prolonged motor endplate contractures in response to brief tetanic nerve stimulation at 20-50 Hz. In some muscle fibers, Fluo-4 fluorescence showed association of these contractures with explosive increases in Ca2+ ("calcium bombs") localized to motor endplates. Calcium bombs were strongly and selectively mitigated by increasing Mg2+ concentration in the bathing medium from 1 to 5 mM. Overnight culture of nerve-muscle preparations from WldS mice in omethoate or other OP insecticide components and their metabolites (dimethoate, cyclohexanone, and cyclohexanol) induced degeneration of NMJs. This degeneration was also strongly mitigated by increasing [Mg2+] from 1 to 5 mM. Thus, equivalent increases in extracellular [Mg2+] mitigated both post-synaptic calcium bombs and degeneration of NMJs. The data support a link between Ca2+ and excitotoxicity at NMJs and suggest that elevating extracellular [Mg2+] could be an effective intervention in treatment of synaptic pathology induced by excitotoxic triggers.
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Affiliation(s)
- Kosala N. Dissanayake
- Euan MacDonald Centre for Motor Neurone Disease Research, The University of Edinburgh, Edinburgh, United Kingdom,Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| | - Robert R. Redman
- Euan MacDonald Centre for Motor Neurone Disease Research, The University of Edinburgh, Edinburgh, United Kingdom,Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| | - Harry Mackenzie
- Euan MacDonald Centre for Motor Neurone Disease Research, The University of Edinburgh, Edinburgh, United Kingdom,Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| | - Michael Eddleston
- Clinical Pharmacology, Toxicology and Therapeutics, Centre for Cardiovascular Science, Queen’s Medical Research Institute, The University of Edinburgh, Edinburgh, United Kingdom
| | - Richard R. Ribchester
- Euan MacDonald Centre for Motor Neurone Disease Research, The University of Edinburgh, Edinburgh, United Kingdom,Centre for Discovery Brain Sciences, The University of Edinburgh, Edinburgh, United Kingdom,*Correspondence: Richard R. Ribchester,
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22
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Coleman MP. Axon Biology in ALS: Mechanisms of Axon Degeneration and Prospects for Therapy. Neurotherapeutics 2022; 19:1133-1144. [PMID: 36207571 PMCID: PMC9587191 DOI: 10.1007/s13311-022-01297-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/02/2022] [Indexed: 10/10/2022] Open
Abstract
This review addresses the longstanding debate over whether amyotrophic lateral sclerosis (ALS) is a 'dying back' or 'dying forward' disorder in the light of new gene identifications and the increased understanding of mechanisms of action for previously identified ALS genes. While the topological pattern of pathology in animal models, and more anecdotally in patients is indeed 'dying back', this review discusses how this fits with the fact that many of the major initiating events are thought to occur within the soma. It also discusses how widely varying ALS risk factors, including some impacting axons directly, may combine to drive a common pathway involving TAR DNA binding protein 43 (TDP-43) and neuromuscular junction (NMJ) denervation. The emerging association between sterile alpha and TIR motif-containing 1 (SARM1), a protein so far mostly associated with axon degeneration, and sporadic ALS is another major theme. The strengths and limitations of the current evidence supporting an association are considered, along with ways in which SARM1 could become activated in ALS. The final section addresses SARM1-based therapies along with the prospects for targeting other axonal steps in ALS pathogenesis.
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Affiliation(s)
- Michael P Coleman
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Robinson Way, Cambridge, CB2 0PY, UK.
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23
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Chandrasekaran K, Najimi N, Sagi AR, Yarlagadda S, Salimian M, Arvas MI, Hedayat AF, Kevas Y, Kadakia A, Russell JW. NAD + Precursors Repair Mitochondrial Function in Diabetes and Prevent Experimental Diabetic Neuropathy. Int J Mol Sci 2022; 23:4887. [PMID: 35563288 PMCID: PMC9102948 DOI: 10.3390/ijms23094887] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 04/18/2022] [Accepted: 04/26/2022] [Indexed: 12/04/2022] Open
Abstract
Axon degeneration in diabetic peripheral neuropathy (DPN) is associated with impaired NAD+ metabolism. We tested whether the administration of NAD+ precursors, nicotinamide mononucleotide (NMN) or nicotinamide riboside (NR), prevents DPN in models of Type 1 and Type 2 diabetes. NMN was administered to streptozotocin (STZ)-induced diabetic rats and STZ-induced diabetic mice by intraperitoneal injection at 50 or 100 mg/kg on alternate days for 2 months. mice The were fed with a high fat diet (HFD) for 2 months with or without added NR at 150 or 300 mg/kg for 2 months. The administration of NMN to STZ-induced diabetic rats or mice or dietary addition of NR to HFD-fed mice improved sensory function, normalized sciatic and tail nerve conduction velocities, and prevented loss of intraepidermal nerve fibers in skin samples from the hind-paw. In adult dorsal root ganglion (DRG) neurons isolated from HFD-fed mice, there was a decrease in NAD+ levels and mitochondrial maximum reserve capacity. These impairments were normalized in isolated DRG neurons from NR-treated mice. The results indicate that the correction of NAD+ depletion in DRG may be sufficient to prevent DPN but does not significantly affect glucose tolerance, insulin levels, or insulin resistance.
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Affiliation(s)
- Krish Chandrasekaran
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (N.N.); (A.R.S.); (S.Y.); (M.S.); (M.I.A.); (A.F.H.); (Y.K.); (A.K.)
- Veterans Affairs Medical Center, Baltimore, MD 21201, USA
| | - Neda Najimi
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (N.N.); (A.R.S.); (S.Y.); (M.S.); (M.I.A.); (A.F.H.); (Y.K.); (A.K.)
| | - Avinash R. Sagi
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (N.N.); (A.R.S.); (S.Y.); (M.S.); (M.I.A.); (A.F.H.); (Y.K.); (A.K.)
| | - Sushuma Yarlagadda
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (N.N.); (A.R.S.); (S.Y.); (M.S.); (M.I.A.); (A.F.H.); (Y.K.); (A.K.)
| | - Mohammad Salimian
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (N.N.); (A.R.S.); (S.Y.); (M.S.); (M.I.A.); (A.F.H.); (Y.K.); (A.K.)
| | - Muhammed Ikbal Arvas
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (N.N.); (A.R.S.); (S.Y.); (M.S.); (M.I.A.); (A.F.H.); (Y.K.); (A.K.)
| | - Ahmad F. Hedayat
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (N.N.); (A.R.S.); (S.Y.); (M.S.); (M.I.A.); (A.F.H.); (Y.K.); (A.K.)
| | - Yanni Kevas
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (N.N.); (A.R.S.); (S.Y.); (M.S.); (M.I.A.); (A.F.H.); (Y.K.); (A.K.)
| | - Anand Kadakia
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (N.N.); (A.R.S.); (S.Y.); (M.S.); (M.I.A.); (A.F.H.); (Y.K.); (A.K.)
| | - James W. Russell
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; (K.C.); (N.N.); (A.R.S.); (S.Y.); (M.S.); (M.I.A.); (A.F.H.); (Y.K.); (A.K.)
- Veterans Affairs Medical Center, Baltimore, MD 21201, USA
- CAMC Institute for Academic Medicine, 415 Morris Street Suite 300, Charleston, WV 25301, USA
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24
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Msheik Z, El Massry M, Rovini A, Billet F, Desmoulière A. The macrophage: a key player in the pathophysiology of peripheral neuropathies. J Neuroinflammation 2022; 19:97. [PMID: 35429971 PMCID: PMC9013246 DOI: 10.1186/s12974-022-02454-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 03/29/2022] [Indexed: 12/22/2022] Open
Abstract
Macrophages are present in all mammalian tissues and coexist with various cell types in order to respond to different environmental cues. However, the role of these cells has been underestimated in the context of peripheral nerve damage. More importantly, macrophages display divergent characteristics, associated with their origin, and in response to the modulatory effects of their microenvironment. Interestingly, the advent of new techniques such as fate mapping and single-cell transcriptomics and their synergistic use has helped characterize in detail the origin and fate of tissue-resident macrophages in the peripheral nervous system (PNS). Furthermore, these techniques have allowed a better understanding of their functions from simple homeostatic supervisors to chief regulators in peripheral neuropathies. In this review, we summarize the latest knowledge about macrophage ontogeny, function and tissue identity, with a particular focus on PNS-associated cells, as well as their interaction with reactive oxygen species under physiological and pathological conditions. We then revisit the process of Wallerian degeneration, describing the events accompanying axon degeneration, Schwann cell activation and most importantly, macrophage recruitment to the site of injury. Finally, we review these processes in light of internal and external insults to peripheral nerves leading to peripheral neuropathies, the involvement of macrophages and the potential benefit of the targeting of specific macrophages for the alleviation of functional defects in the PNS.
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25
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Moss KR, Johnson AE, Bopp TS, Yu ATY, Perry K, Chung T, Höke A. SARM1 knockout does not rescue neuromuscular phenotypes in a Charcot-Marie-Tooth disease Type 1A mouse model. J Peripher Nerv Syst 2022; 27:58-66. [PMID: 35137510 PMCID: PMC8940700 DOI: 10.1111/jns.12483] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 01/25/2022] [Accepted: 02/02/2022] [Indexed: 11/28/2022]
Abstract
Charcot-Marie-Tooth disease Type 1A (CMT1A) is caused by duplication of the PMP22 gene and is the most common inherited peripheral neuropathy. Although CMT1A is a dysmyelinating peripheral neuropathy, secondary axon degeneration has been suggested to drive functional deficits in patients. Given that SARM1 knockout is a potent inhibitor of the programmed axon degeneration pathway, we asked whether SARM1 knockout rescues neuromuscular phenotypes in CMT1A model (C3-PMP) mice. CMT1A mice were bred with SARM1 knockout mice to generate CMT1A/SARM1-/- mice. A series of behavioral assays were employed to evaluate motor and sensorimotor function. Electrophysiological and histological studies of the tibial branch of the sciatic nerve were performed. Additionally, gastrocnemius and soleus muscle morphology were evaluated histologically. Although clear behavioral and electrophysiological deficits were observed in CMT1A model mice, genetic deletion of SARM1 conferred no significant improvement. Nerve morphometry revealed predominantly myelin deficits in CMT1A model mice and SARM1 knockout yielded no improvement in all nerve morphometry measures. Similarly, muscle morphometry deficits in CMT1A model mice were not improved by SARM1 knockout. Our findings demonstrate that programmed axon degeneration pathway inhibition does not provide therapeutic benefit in C3-PMP CMT1A model mice. Our results indicate that the clinical phenotypes observed in CMT1A mice are likely caused primarily by prolonged dysmyelination, motivate further investigation into mechanisms of dysmyelination in these mice and necessitate the development of improved CMT1A rodent models that recapitulate the secondary axon degeneration observed in patients.
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Affiliation(s)
- Kathryn R. Moss
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD
| | - Anna E. Johnson
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD
| | - Taylor S. Bopp
- Department of Physical Medicine and Rehabilitation, Johns Hopkins School of Medicine, Baltimore, MD
| | - Andrew T-Y. Yu
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD
| | - Ken Perry
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD
| | - Tae Chung
- Department of Physical Medicine and Rehabilitation, Johns Hopkins School of Medicine, Baltimore, MD
| | - Ahmet Höke
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD,Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD,Corresponding Author: Ahmet Höke MD, PhD, Johns Hopkins School of Medicine, 855 N. Wolfe St., Baltimore, MD 21205, Tel: 410-955-2227, Fax: 410-502-5459,
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26
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Angeletti C, Amici A, Gilley J, Loreto A, Trapanotto AG, Antoniou C, Merlini E, Coleman MP, Orsomando G. SARM1 is a multi-functional NAD(P)ase with prominent base exchange activity, all regulated bymultiple physiologically relevant NAD metabolites. iScience 2022; 25:103812. [PMID: 35198877 PMCID: PMC8844822 DOI: 10.1016/j.isci.2022.103812] [Citation(s) in RCA: 46] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 12/13/2021] [Accepted: 01/20/2022] [Indexed: 12/11/2022] Open
Abstract
SARM1 is an NAD(P) glycohydrolase and TLR adapter with an essential, prodegenerative role in programmed axon death (Wallerian degeneration). Like other NAD(P)ases, it catalyzes multiple reactions that need to be fully investigated. Here, we compare these multiple activities for recombinant human SARM1, human CD38, and Aplysia californica ADP ribosyl cyclase. SARM1 has the highest transglycosidation (base exchange) activity at neutral pH and with some bases this dominates NAD(P) hydrolysis and cyclization. All SARM1 activities, including base exchange at neutral pH, are activated by an increased NMN:NAD ratio, at physiological levels of both metabolites. SARM1 base exchange occurs also in DRG neurons and is thus a very likely physiological source of calcium-mobilizing agent NaADP. Finally, we identify regulation by free pyridines, NADP, and nicotinic acid riboside (NaR) on SARM1, all of therapeutic interest. Understanding which specific SARM1 function(s) is responsible for axon degeneration is essential for its targeting in disease. Base exchange is a prominent, and sometimes completely dominant, SARM1 activity Physiologically relevant NMN:NAD ratios may regulate all of SARM1's multiple activities Physiological NADP may inhibit SARM1 more potently than NAD and via a distinct site NaR and VR both selectively inhibit SARM1 and are thus possible effectors or drug leads
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27
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Bloom AJ, Mao X, Strickland A, Sasaki Y, Milbrandt J, DiAntonio A. Constitutively active SARM1 variants that induce neuropathy are enriched in ALS patients. Mol Neurodegener 2022; 17:1. [PMID: 34991663 PMCID: PMC8739729 DOI: 10.1186/s13024-021-00511-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 12/17/2021] [Indexed: 03/31/2023] Open
Abstract
Background In response to injury, neurons activate a program of organized axon self-destruction initiated by the NAD+ hydrolase, SARM1. In healthy neurons SARM1 is autoinhibited, but single amino acid changes can abolish autoinhibition leading to constitutively active SARM1 enzymes that promote degeneration when expressed in cultured neurons. Methods To investigate whether naturally occurring human variants might disrupt SARM1 autoinhibition and potentially contribute to risk for neurodegenerative disease, we assayed the enzymatic activity of all 42 rare SARM1 alleles identified among 8507 amyotrophic lateral sclerosis (ALS) patients and 9671 controls. We then intrathecally injected mice with virus expressing SARM1 constructs to test the capacity of an ALS-associated constitutively active SARM1 variant to promote neurodegeneration in vivo. Results Twelve out of 42 SARM1 missense variants or small in-frame deletions assayed exhibit constitutive NADase activity, including more than half of those that are unique to the ALS patients or that occur in multiple patients. There is a > 5-fold enrichment of constitutively active variants among patients compared to controls. Expression of constitutively active ALS-associated SARM1 alleles in cultured dorsal root ganglion (DRG) neurons is pro-degenerative and cytotoxic. Intrathecal injection of an AAV expressing the common SARM1 reference allele is innocuous to mice, but a construct harboring SARM1V184G, the constitutively active variant found most frequently among the ALS patients, causes axon loss, motor dysfunction, and sustained neuroinflammation. Conclusions These results implicate rare hypermorphic SARM1 alleles as candidate genetic risk factors for ALS and other neurodegenerative conditions. Supplementary Information The online version contains supplementary material available at 10.1186/s13024-021-00511-x.
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Affiliation(s)
- A Joseph Bloom
- Needleman Center for Neurometabolism and Axonal Therapeutics and Department of Genetics, Washington University School of Medicine in Saint Louis, St. Louis, MO, USA.
| | - Xianrong Mao
- Needleman Center for Neurometabolism and Axonal Therapeutics and Department of Genetics, Washington University School of Medicine in Saint Louis, St. Louis, MO, USA
| | - Amy Strickland
- Needleman Center for Neurometabolism and Axonal Therapeutics and Department of Genetics, Washington University School of Medicine in Saint Louis, St. Louis, MO, USA
| | - Yo Sasaki
- Needleman Center for Neurometabolism and Axonal Therapeutics and Department of Genetics, Washington University School of Medicine in Saint Louis, St. Louis, MO, USA
| | - Jeffrey Milbrandt
- Needleman Center for Neurometabolism and Axonal Therapeutics and Department of Genetics, Washington University School of Medicine in Saint Louis, St. Louis, MO, USA.
| | - Aaron DiAntonio
- Needleman Center for Neurometabolism and Axonal Therapeutics and Department of Developmental Biology, Washington University School of Medicine in Saint Louis, St. Louis, MO, USA.
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28
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Varadarajan SG, Hunyara JL, Hamilton NR, Kolodkin AL, Huberman AD. Central nervous system regeneration. Cell 2022; 185:77-94. [PMID: 34995518 PMCID: PMC10896592 DOI: 10.1016/j.cell.2021.10.029] [Citation(s) in RCA: 82] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 10/26/2021] [Accepted: 10/27/2021] [Indexed: 02/06/2023]
Abstract
Neurons of the mammalian central nervous system fail to regenerate. Substantial progress has been made toward identifying the cellular and molecular mechanisms that underlie regenerative failure and how altering those pathways can promote cell survival and/or axon regeneration. Here, we summarize those findings while comparing the regenerative process in the central versus the peripheral nervous system. We also highlight studies that advance our understanding of the mechanisms underlying neural degeneration in response to injury, as many of these mechanisms represent primary targets for restoring functional neural circuits.
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Affiliation(s)
| | - John L Hunyara
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Natalie R Hamilton
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Alex L Kolodkin
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Andrew D Huberman
- Department of Neurobiology, Stanford University, Stanford, CA 94305, USA; Department of Ophthalmology, Stanford University, Stanford, CA 94305, USA.
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29
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Banerjee P, Olmsted-Davis EA, Deswal A, Nguyen MTH, Koutroumpakis E, Palaskas NL, Lin SH, Kotla S, Reyes-Gibby C, Yeung SCJ, Yusuf SW, Yoshimoto M, Kobayashi M, Yu B, Schadler K, Herrmann J, Cooke JP, Jain A, Chini E, Le NT, Abe JI. Cancer treatment-induced NAD+ depletion in premature senescence and late cardiovascular complications. THE JOURNAL OF CARDIOVASCULAR AGING 2022; 2:28. [PMID: 35801078 PMCID: PMC9258520 DOI: 10.20517/jca.2022.13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Numerous studies have revealed the critical role of premature senescence induced by various cancer treatment modalities in the pathogenesis of aging-related diseases. Senescence-associated secretory phenotype (SASP) can be induced by telomere dysfunction. Telomeric DNA damage response induced by some cancer treatments can persist for months, possibly accounting for long-term sequelae of cancer treatments. Telomeric DNA damage-induced mitochondrial dysfunction and increased reactive oxygen species production are hallmarks of premature senescence. Recently, we reported that the nucleus-mitochondria positive feedback loop formed by p90 ribosomal S6 kinase (p90RSK) and phosphorylation of S496 on ERK5 (a unique member of the mitogen-activated protein kinase family that is not only a kinase but also a transcriptional co-activator) were vital signaling events that played crucial roles in linking mitochondrial dysfunction, nuclear telomere dysfunction, persistent SASP induction, and atherosclerosis. In this review, we will discuss the role of NAD+ depletion in instigating SASP and its downstream signaling and regulatory mechanisms that lead to the premature onset of atherosclerotic cardiovascular diseases in cancer survivors.
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Affiliation(s)
- Priyanka Banerjee
- Academic Institute, Department of Cardiovascular Sciences, Center for Cardiovascular Sciences, Houston Methodist Research Institute, Weill Cornell Medical College, Houston, TX 77030, USA
| | - Elizabeth A. Olmsted-Davis
- Academic Institute, Department of Cardiovascular Sciences, Center for Cardiovascular Sciences, Houston Methodist Research Institute, Weill Cornell Medical College, Houston, TX 77030, USA
| | - Anita Deswal
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Minh TH. Nguyen
- Academic Institute, Department of Cardiovascular Sciences, Center for Cardiovascular Sciences, Houston Methodist Research Institute, Weill Cornell Medical College, Houston, TX 77030, USA.,University of Science and Technology of Hanoi, Vietnam Academy of Science and Technology, Hanoi 122100, Vietnam
| | - Efstratios Koutroumpakis
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Nicholas L. Palaskas
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Steven H. Lin
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Sivareddy Kotla
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Cielito Reyes-Gibby
- Department of Emergency Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Sai-Ching J. Yeung
- Department of Emergency Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Syed Wamique Yusuf
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Momoko Yoshimoto
- Center for Stem Cell & Regenerative Medicine, The University of Texas Health Science Center of Houston, TX 77030, USA
| | - Michihiro Kobayashi
- Center for Stem Cell & Regenerative Medicine, The University of Texas Health Science Center of Houston, TX 77030, USA
| | - Bing Yu
- Department of Epidemiology, Human Genetics and Environmental Sciences School of Public Health, The University of Texas Health Science Center of Houston, TX 77030, USA
| | - Keri Schadler
- Department of Pediatrics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Joerg Herrmann
- Cardio Oncology Clinic, Division of Preventive Cardiology, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - John P. Cooke
- Academic Institute, Department of Cardiovascular Sciences, Center for Cardiovascular Sciences, Houston Methodist Research Institute, Weill Cornell Medical College, Houston, TX 77030, USA
| | - Abhishek Jain
- Department of Biomedical Engineering, Texas A&M, College Station, TX 77843, USA
| | - Eduardo Chini
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Nhat-Tu Le
- Academic Institute, Department of Cardiovascular Sciences, Center for Cardiovascular Sciences, Houston Methodist Research Institute, Weill Cornell Medical College, Houston, TX 77030, USA
| | - Jun-Ichi Abe
- Department of Cardiology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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30
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Sarm1 haploinsufficiency or low expression levels after antisense oligonucleotides delay programmed axon degeneration. Cell Rep 2021; 37:110108. [PMID: 34910914 PMCID: PMC8692746 DOI: 10.1016/j.celrep.2021.110108] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 08/24/2021] [Accepted: 11/17/2021] [Indexed: 12/28/2022] Open
Abstract
Activation of the pro-degenerative protein SARM1 after diverse physical and disease-relevant injuries causes programmed axon degeneration. Original studies indicate that substantially decreased SARM1 levels are required for neuroprotection. However, we demonstrate, in Sarm1 haploinsufficient mice, that lowering SARM1 levels by 50% delays programmed axon degeneration in vivo after sciatic nerve transection and partially prevents neurite outgrowth defects in mice lacking the pro-survival factor NMNAT2. In vitro, the rate of degeneration in response to traumatic, neurotoxic, and genetic triggers of SARM1 activation is also slowed. Finally, we demonstrate that Sarm1 antisense oligonucleotides decrease SARM1 levels by more than 50% in vitro, which delays or prevents programmed axon degeneration. Combining Sarm1 haploinsufficiency with antisense oligonucleotides further decreases SARM1 levels and prolongs protection after neurotoxic injury. These data demonstrate that axon protection occurs in a Sarm1 gene dose-responsive manner and that SARM1-lowering agents have therapeutic potential, making Sarm1-targeting antisense oligonucleotides a promising therapeutic strategy. SARM1-dependent axon degeneration occurs after diverse neurotoxic triggers Silencing one allele of pro-degenerative SARM1 slows programmed axon degeneration Sarm1 ASOs can mimic this, delaying axon degeneration in multiple contexts Decreasing SARM1 expression even partially may be therapeutically valuable
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31
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Loreto A, Angeletti C, Gu W, Osborne A, Nieuwenhuis B, Gilley J, Merlini E, Arthur-Farraj P, Amici A, Luo Z, Hartley-Tassell L, Ve T, Desrochers LM, Wang Q, Kobe B, Orsomando G, Coleman MP. Neurotoxin-mediated potent activation of the axon degeneration regulator SARM1. eLife 2021; 10:72823. [PMID: 34870595 PMCID: PMC8758145 DOI: 10.7554/elife.72823] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 12/05/2021] [Indexed: 11/13/2022] Open
Abstract
Axon loss underlies symptom onset and progression in many neurodegenerative disorders. Axon degeneration in injury and disease is promoted by activation of the NAD-consuming enzyme SARM1. Here, we report a novel activator of SARM1, a metabolite of the pesticide and neurotoxin vacor. Removal of SARM1 completely rescues mouse neurons from vacor-induced neuron and axon death in vitro and in vivo. We present the crystal structure of the Drosophila SARM1 regulatory domain complexed with this activator, the vacor metabolite VMN, which as the most potent activator yet known is likely to support drug development for human SARM1 and NMNAT2 disorders. This study indicates the mechanism of neurotoxicity and pesticide action by vacor, raises important questions about other pyridines in wider use today, provides important new tools for drug discovery, and demonstrates that removing SARM1 can robustly block programmed axon death induced by toxicity as well as genetic mutation.
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Affiliation(s)
- Andrea Loreto
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Carlo Angeletti
- Department of Clinical Sciences (DISCO), Section of Biochemistry, Polytechnic University of Marche, Ancona, Italy
| | - Weixi Gu
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Australia
| | - Andrew Osborne
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Bart Nieuwenhuis
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Jonathan Gilley
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Elisa Merlini
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Peter Arthur-Farraj
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Adolfo Amici
- Department of Clinical Sciences (DISCO), Section of Biochemistry, Polytechnic University of Marche, Ancona, Italy
| | - Zhenyao Luo
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Australia
| | | | - Thomas Ve
- Institute for Glycomics, Griffith University, Southport, Australia
| | - Laura M Desrochers
- Neuroscience, BioPharmaceuticals R and D, AstraZeneca, Waltham, United States
| | - Qi Wang
- Neuroscience, BioPharmaceuticals R and D, AstraZeneca, Waltham, United States
| | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Australia
| | - Giuseppe Orsomando
- Department of Clinical Sciences (DISCO), Section of Biochemistry, Polytechnic University of Marche, Ancona, Italy
| | - Michael P Coleman
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
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Mitochondrial dysfunction as a trigger of programmed axon death. Trends Neurosci 2021; 45:53-63. [PMID: 34852932 DOI: 10.1016/j.tins.2021.10.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 10/05/2021] [Accepted: 10/29/2021] [Indexed: 12/31/2022]
Abstract
Mitochondrial failure has long been associated with programmed axon death (Wallerian degeneration, WD), a widespread and potentially preventable mechanism of axon degeneration. While early findings in axotomised axons indicated that mitochondria are involved during the execution steps of this pathway, recent studies suggest that in addition, mitochondrial dysfunction can initiate programmed axon death without physical injury. As mitochondrial dysfunction is associated with disorders involving early axon loss, including Parkinson's disease, peripheral neuropathies, and multiple sclerosis, the findings that programmed axon death is activated by mitochondrial impairment could indicate the involvement of druggable mechanisms whose disruption may protect axons in such diseases. Here, we review the latest developments linking mitochondrial dysfunction to programmed axon death and discuss their implications for injury and disease.
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Lundt S, Ding S. NAD + Metabolism and Diseases with Motor Dysfunction. Genes (Basel) 2021; 12:1776. [PMID: 34828382 PMCID: PMC8625820 DOI: 10.3390/genes12111776] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 11/04/2021] [Accepted: 11/05/2021] [Indexed: 12/12/2022] Open
Abstract
Neurodegenerative diseases result in the progressive deterioration of the nervous system, with motor and cognitive impairments being the two most observable problems. Motor dysfunction could be caused by motor neuron diseases (MNDs) characterized by the loss of motor neurons, such as amyotrophic lateral sclerosis and Charcot-Marie-Tooth disease, or other neurodegenerative diseases with the destruction of brain areas that affect movement, such as Parkinson's disease and Huntington's disease. Nicotinamide adenine dinucleotide (NAD+) is one of the most abundant metabolites in the human body and is involved with numerous cellular processes, including energy metabolism, circadian clock, and DNA repair. NAD+ can be reversibly oxidized-reduced or directly consumed by NAD+-dependent proteins. NAD+ is synthesized in cells via three different paths: the de novo, Preiss-Handler, or NAD+ salvage pathways, with the salvage pathway being the primary producer of NAD+ in mammalian cells. NAD+ metabolism is being investigated for a role in the development of neurodegenerative diseases. In this review, we discuss cellular NAD+ homeostasis, looking at NAD+ biosynthesis and consumption, with a focus on the NAD+ salvage pathway. Then, we examine the research, including human clinical trials, focused on the involvement of NAD+ in MNDs and other neurodegenerative diseases with motor dysfunction.
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Affiliation(s)
- Samuel Lundt
- Dalton Cardiovascular Research Center, University of Missouri-Columbia, Columbia, MO 65211, USA;
- Interdisciplinary Neuroscience Program, University of Missouri-Columbia, Columbia, MO 65211, USA
| | - Shinghua Ding
- Dalton Cardiovascular Research Center, University of Missouri-Columbia, Columbia, MO 65211, USA;
- Department of Biomedical, Biological and Chemical Engineering, University of Missouri-Columbia, Columbia, MO 65211, USA
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Dissanayake KN, Margetiny F, Whitmore CL, Chou RCC, Roesl C, Patel V, McArdle JJ, Webster R, Beeson D, Tattersall JEH, Wyllie DJA, Eddleston M, Ribchester RR. Antagonistic postsynaptic and presynaptic actions of cyclohexanol on neuromuscular synaptic transmission and function. J Physiol 2021; 599:5417-5449. [PMID: 34748643 DOI: 10.1113/jp281921] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 11/01/2021] [Indexed: 01/20/2023] Open
Abstract
Intentional ingestion of agricultural organophosphorus insecticides is a significant public health issue in rural Asia, causing thousands of deaths annually. Some survivors develop a severe, acute or delayed myasthenic syndrome. In animal models, similar myasthenia has been associated with increasing plasma concentration of one insecticide solvent metabolite, cyclohexanol. We investigated possible mechanisms using voltage and current recordings from mouse neuromuscular junctions (NMJs) and transfected human cell lines. Cyclohexanol (10-25 mM) reduced endplate potential (EPP) amplitudes by 10-40% and enhanced depression during repetitive (2-20 Hz) stimulation by up to 60%. EPP decay was prolonged more than twofold. Miniature EPPs were attenuated by more than 50%. Cyclohexanol inhibited whole-cell currents recorded from CN21 cells expressing human postjunctional acetylcholine receptors (hnAChR) with an IC50 of 3.74 mM. Cyclohexanol (10-20 mM) also caused prolonged episodes of reduced-current, multi-channel bursting in outside-out patch recordings from hnAChRs expressed in transfected HEK293T cells, reducing charge transfer by more than 50%. Molecular modelling indicated cyclohexanol binding (-6 kcal/mol) to a previously identified alcohol binding site on nicotinic AChR α-subunits. Cyclohexanol also increased quantal content of evoked transmitter release by ∼50%. In perineurial recordings, cyclohexanol selectively inhibited presynaptic K+ currents. Modelling indicated cyclohexanol binding (-3.8 kcal/mol) to voltage-sensitive K+ channels at the same site as tetraethylammonium (TEA). TEA (10 mM) blocked K+ channels more effectively than cyclohexanol but EPPs were more prolonged in 20 mM cyclohexanol. The results explain the pattern of neuromuscular dysfunction following ingestion of organophosphorus insecticides containing cyclohexanol precursors and suggest that cyclohexanol may facilitate investigation of mechanisms regulating synaptic strength at NMJs. KEY POINTS: Intentional ingestion of agricultural organophosphorus insecticides is a significant public health issue in rural Asia, causing thousands of deaths annually. Survivors may develop a severe myasthenic syndrome or paralysis, associated with increased plasma levels of cyclohexanol, an insecticide solvent metabolite. Analysis of synaptic transmission at neuromuscular junctions in isolated mouse skeletal muscle, using isometric tension recording and microelectrode recording of endplate voltages and currents, showed that cyclohexanol reduced postsynaptic sensitivity to acetylcholine neurotransmitter (reduced quantal size) while simultaneously enhancing evoked transmitter release (increased quantal content). Patch recording from transfected cell lines, together with molecular modelling, indicated that cyclohexanol causes selective, allosteric antagonism of postsynaptic nicotinic acetylcholine receptors and block of presynaptic K+ -channel function. The data provide insight into the cellular and molecular mechanisms of neuromuscular weakness following intentional ingestion of agricultural organophosphorus insecticides. Our findings also extend understanding of the effects of alcohols on synaptic transmission and homeostatic synaptic function.
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Affiliation(s)
- Kosala N Dissanayake
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Pharmacology, Toxicology and Therapeutics, Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - Filip Margetiny
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | | | - Robert C-C Chou
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Cornelia Roesl
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Vishwendra Patel
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, State University of New Jersey, Newark, NJ, USA
| | - Joseph J McArdle
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, State University of New Jersey, Newark, NJ, USA
| | - Richard Webster
- Weatherall Institute for Molecular Medicine, Radcliffe Infirmary, Oxford, UK
| | - David Beeson
- Weatherall Institute for Molecular Medicine, Radcliffe Infirmary, Oxford, UK
| | | | - David J A Wyllie
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Centre for Brain Development and Repair, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore, India
| | - Michael Eddleston
- Pharmacology, Toxicology and Therapeutics, Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK
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Roesl C, Evans ER, Dissanayake KN, Boczonadi V, Jones RA, Jordan GR, Ledahawsky L, Allen GCC, Scott M, Thomson A, Wishart TM, Hughes DI, Mead RJ, Shone CC, Slater CR, Gillingwater TH, Skehel PA, Ribchester RR. Confocal Endomicroscopy of Neuromuscular Junctions Stained with Physiologically Inert Protein Fragments of Tetanus Toxin. Biomolecules 2021; 11:1499. [PMID: 34680132 PMCID: PMC8534034 DOI: 10.3390/biom11101499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/07/2021] [Accepted: 10/08/2021] [Indexed: 01/09/2023] Open
Abstract
Live imaging of neuromuscular junctions (NMJs) in situ has been constrained by the suitability of ligands for inert vital staining of motor nerve terminals. Here, we constructed several truncated derivatives of the tetanus toxin C-fragment (TetC) fused with Emerald Fluorescent Protein (emGFP). Four constructs, namely full length emGFP-TetC (emGFP-865:TetC) or truncations comprising amino acids 1066-1315 (emGFP-1066:TetC), 1093-1315 (emGFP-1093:TetC) and 1109-1315 (emGFP-1109:TetC), produced selective, high-contrast staining of motor nerve terminals in rodent or human muscle explants. Isometric tension and intracellular recordings of endplate potentials from mouse muscles indicated that neither full-length nor truncated emGFP-TetC constructs significantly impaired NMJ function or transmission. Motor nerve terminals stained with emGFP-TetC constructs were readily visualised in situ or in isolated preparations using fibre-optic confocal endomicroscopy (CEM). emGFP-TetC derivatives and CEM also visualised regenerated NMJs. Dual-waveband CEM imaging of preparations co-stained with fluorescent emGFP-TetC constructs and Alexa647-α-bungarotoxin resolved innervated from denervated NMJs in axotomized WldS mouse muscle and degenerating NMJs in transgenic SOD1G93A mouse muscle. Our findings highlight the region of the TetC fragment required for selective binding and visualisation of motor nerve terminals and show that fluorescent derivatives of TetC are suitable for in situ morphological and physiological characterisation of healthy, injured and diseased NMJs.
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Affiliation(s)
- Cornelia Roesl
- Centre for Discovery Brain Sciences and the Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK; (C.R.); (K.N.D.); (R.A.J.); (G.R.J.); (L.L.); (G.C.C.A.); (M.S.); (A.T.); (T.H.G.)
| | - Elizabeth R. Evans
- Public Health England, National Infection Service, Porton Down, Salisbury SP4 0JG, UK; (E.R.E.); (C.C.S.)
| | - Kosala N. Dissanayake
- Centre for Discovery Brain Sciences and the Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK; (C.R.); (K.N.D.); (R.A.J.); (G.R.J.); (L.L.); (G.C.C.A.); (M.S.); (A.T.); (T.H.G.)
| | - Veronika Boczonadi
- Applied Neuromuscular Junction Facility, Bio-Imaging Unit, Biosciences Institute, University of Newcastle-upon-Tyne, Framlington Place, Newcastle-upon-Tyne NE2 4HH, UK; (V.B.); (C.R.S.)
| | - Ross A. Jones
- Centre for Discovery Brain Sciences and the Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK; (C.R.); (K.N.D.); (R.A.J.); (G.R.J.); (L.L.); (G.C.C.A.); (M.S.); (A.T.); (T.H.G.)
| | - Graeme R. Jordan
- Centre for Discovery Brain Sciences and the Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK; (C.R.); (K.N.D.); (R.A.J.); (G.R.J.); (L.L.); (G.C.C.A.); (M.S.); (A.T.); (T.H.G.)
| | - Leire Ledahawsky
- Centre for Discovery Brain Sciences and the Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK; (C.R.); (K.N.D.); (R.A.J.); (G.R.J.); (L.L.); (G.C.C.A.); (M.S.); (A.T.); (T.H.G.)
| | - Guy C. C. Allen
- Centre for Discovery Brain Sciences and the Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK; (C.R.); (K.N.D.); (R.A.J.); (G.R.J.); (L.L.); (G.C.C.A.); (M.S.); (A.T.); (T.H.G.)
| | - Molly Scott
- Centre for Discovery Brain Sciences and the Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK; (C.R.); (K.N.D.); (R.A.J.); (G.R.J.); (L.L.); (G.C.C.A.); (M.S.); (A.T.); (T.H.G.)
| | - Alanna Thomson
- Centre for Discovery Brain Sciences and the Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK; (C.R.); (K.N.D.); (R.A.J.); (G.R.J.); (L.L.); (G.C.C.A.); (M.S.); (A.T.); (T.H.G.)
| | - Thomas M. Wishart
- The Roslin Institute, Royal (Dick) School of Veterinary Studies, College of Medicine and Veterinary Medicine, University of Edinburgh, Easter Bush, Edinburgh EH25 9RG, UK;
| | - David I. Hughes
- Spinal Cord Research Group, Institute of Neuroscience and Psychology, University of Glasgow, Glasgow G12 8QQ, UK;
| | - Richard J. Mead
- Sheffield Institute for Translational Neuroscience (SITraN), University of Sheffield, Glossop Road, Sheffield S10 2HQ, UK;
| | - Clifford C. Shone
- Public Health England, National Infection Service, Porton Down, Salisbury SP4 0JG, UK; (E.R.E.); (C.C.S.)
| | - Clarke R. Slater
- Applied Neuromuscular Junction Facility, Bio-Imaging Unit, Biosciences Institute, University of Newcastle-upon-Tyne, Framlington Place, Newcastle-upon-Tyne NE2 4HH, UK; (V.B.); (C.R.S.)
| | - Thomas H. Gillingwater
- Centre for Discovery Brain Sciences and the Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK; (C.R.); (K.N.D.); (R.A.J.); (G.R.J.); (L.L.); (G.C.C.A.); (M.S.); (A.T.); (T.H.G.)
| | - Paul A. Skehel
- Centre for Discovery Brain Sciences and the Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK; (C.R.); (K.N.D.); (R.A.J.); (G.R.J.); (L.L.); (G.C.C.A.); (M.S.); (A.T.); (T.H.G.)
| | - Richard R. Ribchester
- Centre for Discovery Brain Sciences and the Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK; (C.R.); (K.N.D.); (R.A.J.); (G.R.J.); (L.L.); (G.C.C.A.); (M.S.); (A.T.); (T.H.G.)
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Arthur-Farraj P, Coleman MP. Lessons from Injury: How Nerve Injury Studies Reveal Basic Biological Mechanisms and Therapeutic Opportunities for Peripheral Nerve Diseases. Neurotherapeutics 2021; 18:2200-2221. [PMID: 34595734 PMCID: PMC8804151 DOI: 10.1007/s13311-021-01125-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2021] [Indexed: 12/25/2022] Open
Abstract
Since Waller and Cajal in the nineteenth and early twentieth centuries, laboratory traumatic peripheral nerve injury studies have provided great insight into cellular and molecular mechanisms governing axon degeneration and the responses of Schwann cells, the major glial cell type of peripheral nerves. It is now evident that pathways underlying injury-induced axon degeneration and the Schwann cell injury-specific state, the repair Schwann cell, are relevant to many inherited and acquired disorders of peripheral nerves. This review provides a timely update on the molecular understanding of axon degeneration and formation of the repair Schwann cell. We discuss how nicotinamide mononucleotide adenylyltransferase 2 (NMNAT2) and sterile alpha TIR motif containing protein 1 (SARM1) are required for axon survival and degeneration, respectively, how transcription factor c-JUN is essential for the Schwann cell response to nerve injury and what each tells us about disease mechanisms and potential therapies. Human genetic association with NMNAT2 and SARM1 strongly suggests aberrant activation of programmed axon death in polyneuropathies and motor neuron disorders, respectively, and animal studies suggest wider involvement including in chemotherapy-induced and diabetic neuropathies. In repair Schwann cells, cJUN is aberrantly expressed in a wide variety of human acquired and inherited neuropathies. Animal models suggest it limits axon loss in both genetic and traumatic neuropathies, whereas in contrast, Schwann cell secreted Neuregulin-1 type 1 drives onion bulb pathology in CMT1A. Finally, we discuss opportunities for drug-based and gene therapies to prevent axon loss or manipulate the repair Schwann cell state to treat acquired and inherited neuropathies and neuronopathies.
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Affiliation(s)
- Peter Arthur-Farraj
- Department of Clinical Neurosciences, John Van Geest Centre for Brain Repair, University of Cambridge, Robinson Way, Cambridge, CB2 0PY, UK.
| | - Michael P Coleman
- Department of Clinical Neurosciences, John Van Geest Centre for Brain Repair, University of Cambridge, Robinson Way, Cambridge, CB2 0PY, UK.
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37
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Li C, Wu LE. Risks and rewards of targeting NAD + homeostasis in the brain. Mech Ageing Dev 2021; 198:111545. [PMID: 34302821 DOI: 10.1016/j.mad.2021.111545] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 07/18/2021] [Accepted: 07/19/2021] [Indexed: 01/29/2023]
Abstract
Strategies to correct declining nicotinamide adenine dinucleotide (NAD+) levels in neurological disease and biological ageing are promising therapeutic candidates. These strategies include supplementing with NAD+ precursors, small molecule activation of NAD+ biosynthetic enzymes, and treatment with small molecule inhibitors of NAD+ consuming enzymes such as CD38, SARM1 or members of the PARP family. While these strategies have shown efficacy in animal models of neurological disease, each of these has the mechanistic potential for adverse events that could preclude their preclinical use. Here, we discuss the implications of these strategies for treating neurological diseases, including potential off-target effects that may be unique to the brain.
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Affiliation(s)
- Catherine Li
- School of Medical Sciences, UNSW Sydney, NSW, 2052, Australia
| | - Lindsay E Wu
- School of Medical Sciences, UNSW Sydney, NSW, 2052, Australia.
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Risner ML, Pasini S, McGrady NR, D’Alessandro KB, Yao V, Cooper ML, Calkins DJ. Neuroprotection by Wld S depends on retinal ganglion cell type and age in glaucoma. Mol Neurodegener 2021; 16:36. [PMID: 34090501 PMCID: PMC8180099 DOI: 10.1186/s13024-021-00459-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 05/26/2021] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Early challenges to axonal physiology, active transport, and ultrastructure are endemic to age-related neurodegenerative disorders, including those affecting the optic nerve. Chief among these, glaucoma causes irreversible vision loss through sensitivity to intraocular pressure (IOP) that challenges retinal ganglion cell (RGC) axons, which comprise the optic nerve. Early RGC axonopathy includes distal to proximal progression that implicates a slow form of Wallerian degeneration. In multiple disease models, including inducible glaucoma, expression of the slow Wallerian degeneration (WldS) allele slows axon degeneration and confers protection to cell bodies. METHODS Using an inducible model of glaucoma along with whole-cell patch clamp electrophysiology and morphological analysis, we tested if WldS also protects RGC light responses and dendrites and, if so, whether this protection depends upon RGC type. We induced glaucoma in young and aged mice to determine if neuroprotection by WldS on anterograde axonal transport and spatial contrast acuity depends on age. RESULTS We found WldS protects dendritic morphology and light-evoked responses of RGCs that signal light onset (αON-Sustained) during IOP elevation. However, IOP elevation significantly reduces dendritic complexity and light responses of RGCs that respond to light offset (αOFF-Sustained) regardless of WldS. As expected, WldS preserves anterograde axon transport and spatial acuity in young adult mice, but its protection is significantly limited in aged mice. CONCLUSION The efficacy of WldS in conferring protection to neurons and their axons varies by cell type and diminishes with age.
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Affiliation(s)
- Michael L. Risner
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave. S, Nashville, TN 37232 USA
| | - Silvia Pasini
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave. S, Nashville, TN 37232 USA
| | - Nolan R. McGrady
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave. S, Nashville, TN 37232 USA
| | - Karis B. D’Alessandro
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave. S, Nashville, TN 37232 USA
| | - Vincent Yao
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave. S, Nashville, TN 37232 USA
| | - Melissa L. Cooper
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave. S, Nashville, TN 37232 USA
| | - David J. Calkins
- Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave. S, Nashville, TN 37232 USA
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Bosanac T, Hughes RO, Engber T, Devraj R, Brearley A, Danker K, Young K, Kopatz J, Hermann M, Berthemy A, Boyce S, Bentley J, Krauss R. Pharmacological SARM1 inhibition protects axon structure and function in paclitaxel-induced peripheral neuropathy. Brain 2021; 144:3226-3238. [PMID: 33964142 PMCID: PMC8634121 DOI: 10.1093/brain/awab184] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 03/02/2021] [Accepted: 04/27/2021] [Indexed: 11/26/2022] Open
Abstract
Axonal degeneration is an early and ongoing event that causes disability and disease progression in many neurodegenerative disorders of the peripheral and central nervous systems. Chemotherapy-induced peripheral neuropathy (CIPN) is a major cause of morbidity and the main cause of dose reductions and discontinuations in cancer treatment. Preclinical evidence indicates that activation of the Wallerian-like degeneration pathway driven by sterile alpha and TIR motif containing 1 (SARM1) is responsible for axonopathy in CIPN. SARM1 is the central driver of an evolutionarily conserved programme of axonal degeneration downstream of chemical, inflammatory, mechanical or metabolic insults to the axon. SARM1 contains an intrinsic NADase enzymatic activity essential for its pro-degenerative functions, making it a compelling therapeutic target to treat neurodegeneration characterized by axonopathies of the peripheral and central nervous systems. Small molecule SARM1 inhibitors have the potential to prevent axonal degeneration in peripheral and central axonopathies and to provide a transformational disease-modifying treatment for these disorders. Using a biochemical assay for SARM1 NADase we identified a novel series of potent and selective irreversible isothiazole inhibitors of SARM1 enzymatic activity that protected rodent and human axons in vitro. In sciatic nerve axotomy, we observed that these irreversible SARM1 inhibitors decreased a rise in nerve cADPR and plasma neurofilament light chain released from injured sciatic nerves in vivo. In a mouse paclitaxel model of CIPN we determined that Sarm1 knockout mice prevented loss of axonal function, assessed by sensory nerve action potential amplitudes of the tail nerve, in a gene-dosage-dependent manner. In that CIPN model, the irreversible SARM1 inhibitors prevented loss of intraepidermal nerve fibres induced by paclitaxel and provided partial protection of axonal function assessed by sensory nerve action potential amplitude and mechanical allodynia.
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Affiliation(s)
- Todd Bosanac
- Disarm Therapeutics, a wholly owned subsidiary of Eli Lilly & Co., Cambridge MA 02142, USA
| | - Robert O Hughes
- Disarm Therapeutics, a wholly owned subsidiary of Eli Lilly & Co., Cambridge MA 02142, USA
| | - Thomas Engber
- Disarm Therapeutics, a wholly owned subsidiary of Eli Lilly & Co., Cambridge MA 02142, USA
| | - Rajesh Devraj
- Disarm Therapeutics, a wholly owned subsidiary of Eli Lilly & Co., Cambridge MA 02142, USA
| | | | | | | | | | | | | | | | | | - Raul Krauss
- Disarm Therapeutics, a wholly owned subsidiary of Eli Lilly & Co., Cambridge MA 02142, USA
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Structural and Mechanistic Regulation of the Pro-degenerative NAD Hydrolase SARM1. Cell Rep 2021; 32:107999. [PMID: 32755591 DOI: 10.1016/j.celrep.2020.107999] [Citation(s) in RCA: 72] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 06/09/2020] [Accepted: 07/14/2020] [Indexed: 01/20/2023] Open
Abstract
The NADase SARM1 is a central switch in injury-activated axon degeneration, an early hallmark of many neurological diseases. Here, we present cryo-electron microscopy (cryo-EM) structures of autoinhibited (3.3 Å) and active SARM1 (6.8 Å) and provide mechanistic insight into the tight regulation of SARM1's function by the local metabolic environment. Although both states retain an octameric core, the defining feature of the autoinhibited state is a lock between the autoinhibitory Armadillo/HEAT motif (ARM) and catalytic Toll/interleukin-1 receptor (TIR) domains, which traps SARM1 in an inactive state. Mutations that break this lock activate SARM1, resulting in catastrophic neuronal death. Notably, the mutants cannot be further activated by the endogenous activator nicotinamide mononucleotide (NMN), and active SARM1 is product inhibited by Nicotinamide (NAM), highlighting SARM1's functional dependence on key metabolites in the NAD salvage pathway. Our studies provide a molecular understanding of SARM1's transition from an autoinhibited to an injury-activated state and lay the foundation for future SARM1-based therapies to treat axonopathies.
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Hill CS, Loreto A. Emergence of the Wallerian degeneration pathway as a mechanism of secondary brain injury. Neural Regen Res 2021; 16:980-981. [PMID: 33229742 PMCID: PMC8178794 DOI: 10.4103/1673-5374.297070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/22/2020] [Accepted: 07/07/2020] [Indexed: 11/04/2022] Open
Affiliation(s)
- Ciaran Scott Hill
- National Hospital for Neurology and Neurosurgery, University College London Hospitals; UCL Cancer Institute, University College London, London, UK
| | - Andrea Loreto
- Jon Van Geest Centre for Brain Repair, University of Cambridge, Cambridge, UK
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Figley MD, Gu W, Nanson JD, Shi Y, Sasaki Y, Cunnea K, Malde AK, Jia X, Luo Z, Saikot FK, Mosaiab T, Masic V, Holt S, Hartley-Tassell L, McGuinness HY, Manik MK, Bosanac T, Landsberg MJ, Kerry PS, Mobli M, Hughes RO, Milbrandt J, Kobe B, DiAntonio A, Ve T. SARM1 is a metabolic sensor activated by an increased NMN/NAD + ratio to trigger axon degeneration. Neuron 2021; 109:1118-1136.e11. [PMID: 33657413 PMCID: PMC8174188 DOI: 10.1016/j.neuron.2021.02.009] [Citation(s) in RCA: 136] [Impact Index Per Article: 45.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 01/15/2021] [Accepted: 02/08/2021] [Indexed: 12/16/2022]
Abstract
Axon degeneration is a central pathological feature of many neurodegenerative diseases. Sterile alpha and Toll/interleukin-1 receptor motif-containing 1 (SARM1) is a nicotinamide adenine dinucleotide (NAD+)-cleaving enzyme whose activation triggers axon destruction. Loss of the biosynthetic enzyme NMNAT2, which converts nicotinamide mononucleotide (NMN) to NAD+, activates SARM1 via an unknown mechanism. Using structural, biochemical, biophysical, and cellular assays, we demonstrate that SARM1 is activated by an increase in the ratio of NMN to NAD+ and show that both metabolites compete for binding to the auto-inhibitory N-terminal armadillo repeat (ARM) domain of SARM1. We report structures of the SARM1 ARM domain bound to NMN and of the homo-octameric SARM1 complex in the absence of ligands. We show that NMN influences the structure of SARM1 and demonstrate via mutagenesis that NMN binding is required for injury-induced SARM1 activation and axon destruction. Hence, SARM1 is a metabolic sensor responding to an increased NMN/NAD+ ratio by cleaving residual NAD+, thereby inducing feedforward metabolic catastrophe and axonal demise.
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Affiliation(s)
- Matthew D Figley
- Department of Developmental Biology, Washington University School of Medicine in Saint Louis, St. Louis, MO, USA; Needleman Center for Neurometabolism and Axonal Therapeutics, Washington University School of Medicine in Saint Louis, St. Louis, MO, USA
| | - Weixi Gu
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia
| | - Jeffrey D Nanson
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia
| | - Yun Shi
- Institute for Glycomics, Griffith University, Southport, QLD 4222, Australia
| | - Yo Sasaki
- Needleman Center for Neurometabolism and Axonal Therapeutics, Washington University School of Medicine in Saint Louis, St. Louis, MO, USA; Department of Genetics, Washington University School of Medicine in Saint Louis, St. Louis, MO, USA
| | - Katie Cunnea
- Evotec (UK) Ltd., 114 Innovation Drive, Milton Park, Abingdon, Oxfordshire OX14 4RZ, UK; Evotec SE, Manfred Eigen Campus, Essener Bogen 7, 22419 Hamburg, Germany
| | - Alpeshkumar K Malde
- Institute for Glycomics, Griffith University, Southport, QLD 4222, Australia
| | - Xinying Jia
- Centre for Advanced Imaging, University of Queensland, Brisbane, QLD 4072, Australia
| | - Zhenyao Luo
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia
| | - Forhad K Saikot
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia
| | - Tamim Mosaiab
- Institute for Glycomics, Griffith University, Southport, QLD 4222, Australia
| | - Veronika Masic
- Institute for Glycomics, Griffith University, Southport, QLD 4222, Australia
| | - Stephanie Holt
- Institute for Glycomics, Griffith University, Southport, QLD 4222, Australia
| | | | - Helen Y McGuinness
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia
| | - Mohammad K Manik
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia
| | - Todd Bosanac
- Disarm Therapeutics, a wholly owned subsidiary of Eli Lilly & Co., Cambridge, MA, USA
| | - Michael J Landsberg
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia
| | - Philip S Kerry
- Evotec (UK) Ltd., 114 Innovation Drive, Milton Park, Abingdon, Oxfordshire OX14 4RZ, UK; Evotec SE, Manfred Eigen Campus, Essener Bogen 7, 22419 Hamburg, Germany
| | - Mehdi Mobli
- Centre for Advanced Imaging, University of Queensland, Brisbane, QLD 4072, Australia
| | - Robert O Hughes
- Disarm Therapeutics, a wholly owned subsidiary of Eli Lilly & Co., Cambridge, MA, USA
| | - Jeffrey Milbrandt
- Needleman Center for Neurometabolism and Axonal Therapeutics, Washington University School of Medicine in Saint Louis, St. Louis, MO, USA; Department of Genetics, Washington University School of Medicine in Saint Louis, St. Louis, MO, USA.
| | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD 4072, Australia.
| | - Aaron DiAntonio
- Department of Developmental Biology, Washington University School of Medicine in Saint Louis, St. Louis, MO, USA; Needleman Center for Neurometabolism and Axonal Therapeutics, Washington University School of Medicine in Saint Louis, St. Louis, MO, USA.
| | - Thomas Ve
- Institute for Glycomics, Griffith University, Southport, QLD 4222, Australia.
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Araki T. [Mechanism of axonal degeneration: from molecular signaling to the development of therapeutic applications]. Nihon Yakurigaku Zasshi 2021; 156:66-70. [PMID: 33642532 DOI: 10.1254/fpj.20089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Neurons communicate with other cells via long processes, i.e., axons and dendrites, functionally and morphologically specialized tree-like structures. Formation and maintenance of such processes play a crucial role in neuronal functions. Axons are particularly important for construction of neuronal network, and, together with synapses at the end of them, play a central role in transmission of information. Axonal degeneration, a phenomenon that once formed axons lose structural integrity, is most typically observed as "Wallerian degeneration", in which injured axonal segment (distal to the site of injury) degenerates. Different forms of axonal degeneration are also observed in a variety of contexts, including pathogenesis and progression of different neurodegenerative disorders, as well as neuronal network formation during development. Thus, understanding of regulatory mechanism of axonal degeneration is important in many aspects, such as for clarification of neuronal morphogenesis mechanism, and for development of neuroprotective therapy against neurological disorders. Here, I discuss recent progress in the research field of axonal degeneration mechanism.
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Affiliation(s)
- Toshiyuki Araki
- Department of Peripheral Nervous System Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry
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44
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Xue T, Sun Q, Zhang Y, Wu X, Shen H, Li X, Wu J, Li H, Wang Z, Chen G. Phosphorylation at S548 as a Functional Switch of Sterile Alpha and TIR Motif-Containing 1 in Cerebral Ischemia/Reperfusion Injury in Rats. Mol Neurobiol 2021; 58:453-469. [PMID: 32968873 DOI: 10.1007/s12035-020-02132-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 09/14/2020] [Indexed: 12/18/2022]
Abstract
Sterile alpha and Toll/interleukin-1 receptor motif-containing 1 (SARM1) is a pro-degenerative molecule in Wallerian degeneration, which is mainly expressed in brain/neurons and colocalized with mitochondria and microtubules. The aim of this study was to determine the role of SARM1 in cerebral ischemia/reperfusion (I/R) injury and the underlying mechanisms. In vivo, a middle cerebral artery occlusion/reperfusion (MCAO/R) model in adult male Sprague Dawley rats (250-300 g) was established, and in vitro, cultured primary neurons were subjected to oxygen-glucose deprivation/reoxygenation (OGD/R) to imitate I/R injury. Overexpression lentiviruses encoding wild-type SARM1 and SARM1 with serine 548 alanine mutation (S548A) were constructed and administered to rats by intra-penumbral injection. First, the potential role of SARM1 in cerebral I/R injury was confirmed by the increased protein levels of SARM1 within penumbra tissue, especially in neurons. Second, there was an increase in the phosphorylation ratio of p-SARM1(S548)/SARM1 at 2 h after MCAO/R. Third, on the basis of site-specific mutagenesis, we identified S548 as a key site for SARM1 phosphorylation in I/R conditions. Fourth, SARM1 (S548A) overexpression reduced infarct size, neuronal death, and neurobehavioral dysfunction, while wild-type SARM1 overexpression had the opposite effects. Finally, we found that SARM1 phosphorylation at the S548 site switched SARM1 function from promoting mitochondrial transport to inhibiting mitochondrial transport along axons after I/R injury. Restriction of SARM1 phosphorylation at S548 may be a promising intervention target for I/R injury; thus, exogenous administration of SARM1 (S548A) may be a novel strategy for improving neurological outcomes.
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Affiliation(s)
- Tao Xue
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Qing Sun
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Yijie Zhang
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Xin Wu
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Haitao Shen
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Xiang Li
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Jiang Wu
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Haiying Li
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China.
| | - Zhong Wang
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China.
| | - Gang Chen
- Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
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45
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Ribchester RR, Mehta AR. Neuromuscular junctions: mind meeting matter. Lancet Neurol 2021; 20:93. [PMID: 33484653 DOI: 10.1016/s1474-4422(20)30486-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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46
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Niu J, Sanders SS, Jeong HK, Holland SM, Sun Y, Collura KM, Hernandez LM, Huang H, Hayden MR, Smith GM, Hu Y, Jin Y, Thomas GM. Coupled Control of Distal Axon Integrity and Somal Responses to Axonal Damage by the Palmitoyl Acyltransferase ZDHHC17. Cell Rep 2020; 33:108365. [PMID: 33207199 PMCID: PMC7803378 DOI: 10.1016/j.celrep.2020.108365] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 08/28/2020] [Accepted: 10/19/2020] [Indexed: 12/25/2022] Open
Abstract
After optic nerve crush (ONC), the cell bodies and distal axons of most retinal ganglion cells (RGCs) degenerate. RGC somal and distal axon degenerations were previously thought to be controlled by two parallel pathways, involving activation of the kinase dual leucine-zipper kinase (DLK) and loss of the axon survival factor nicotinamide mononucleotide adenylyltransferase-2 (NMNAT2), respectively. Here, we report that palmitoylation of both DLK and NMNAT2 by the palmitoyl acyltransferase ZDHHC17 couples these signals. ZDHHC17-dependent palmitoylation enables DLK-dependent somal degeneration after ONC and also ensures NMNAT-dependent distal axon integrity in healthy optic nerves. We provide evidence that ZDHHC17 also controls survival-versus-degeneration decisions in dorsal root ganglion (DRG) neurons, and we identify conserved motifs in NMNAT2 and DLK that govern their ZDHHC17-dependent regulation. These findings suggest that the control of somal and distal axon integrity should be considered as a single, holistic process, mediated by the concerted action of two palmitoylation-dependent pathways.
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Affiliation(s)
- Jingwen Niu
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, Philadelphia, PA 19140, USA
| | - Shaun S Sanders
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, Philadelphia, PA 19140, USA
| | - Hey-Kyeong Jeong
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, Philadelphia, PA 19140, USA
| | - Sabrina M Holland
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, Philadelphia, PA 19140, USA
| | - Yue Sun
- Section of Neurobiology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Kaitlin M Collura
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, Philadelphia, PA 19140, USA
| | - Luiselys M Hernandez
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, Philadelphia, PA 19140, USA
| | - Haoliang Huang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Michael R Hayden
- Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, BC, Canada
| | - George M Smith
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, Philadelphia, PA 19140, USA; Department of Neuroscience, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Yang Hu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto, CA 94304, USA
| | - Yishi Jin
- Section of Neurobiology, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Gareth M Thomas
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, Philadelphia, PA 19140, USA; Department of Anatomy and Cell Biology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA.
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47
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Abstract
It is increasingly recognized that local protein synthesis (LPS) contributes to fundamental aspects of axon biology, in both developing and mature neurons. Mutations in RNA-binding proteins (RBPs), as central players in LPS, and other proteins affecting RNA localization and translation are associated with a range of neurological disorders, suggesting disruption of LPS may be of pathological significance. In this review, we substantiate this hypothesis by examining the link between LPS and key axonal processes, and the implicated pathophysiological consequences of dysregulated LPS. First, we describe how the length and autonomy of axons result in an exceptional reliance on LPS. We next discuss the roles of LPS in maintaining axonal structural and functional polarity and axonal trafficking. We then consider how LPS facilitates the establishment of neuronal connectivity through regulation of axonal branching and pruning, how it mediates axonal survival into adulthood and its involvement in neuronal stress responses.
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Affiliation(s)
- Julie Qiaojin Lin
- UK Dementia Research Institute at University of Cambridge, Department of Clinical Neurosciences, Island Research Building, Cambridge Biomedical Campus, Cambridge, UK
| | | | - Christine E Holt
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
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48
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Figley MD, DiAntonio A. The SARM1 axon degeneration pathway: control of the NAD + metabolome regulates axon survival in health and disease. Curr Opin Neurobiol 2020; 63:59-66. [PMID: 32311648 PMCID: PMC7483800 DOI: 10.1016/j.conb.2020.02.012] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 02/20/2020] [Accepted: 02/25/2020] [Indexed: 02/06/2023]
Abstract
Axons are essential for nervous system function and axonal pathology is a common hallmark of many neurodegenerative diseases. Over a century and a half after the original description of Wallerian axon degeneration, advances over the past five years have heralded the emergence of a comprehensive, mechanistic model of an endogenous axon degenerative process that can be activated by both injury and disease. Axonal integrity is maintained by the opposing actions of the survival factors NMNAT2 and STMN2 and pro-degenerative molecules DLK and SARM1. The balance between axon survival and self-destruction is intimately tied to axonal NAD+ metabolism. These mechanistic insights may enable axon-protective therapies for a variety of human neurodegenerative diseases including peripheral neuropathy, traumatic brain injury and potentially ALS and Parkinson's.
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Affiliation(s)
- Matthew D Figley
- Department of Developmental Biology, Washington University School of Medicine in St. Louis, 660 Euclid Avenue, St. Louis, MO 63110, USA
| | - Aaron DiAntonio
- Department of Developmental Biology, Washington University School of Medicine in St. Louis, 660 Euclid Avenue, St. Louis, MO 63110, USA; Needleman Center for Neurometabolism and Axonal Therapeutics, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA.
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49
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Stassart RM, Woodhoo A. Axo-glial interaction in the injured PNS. Dev Neurobiol 2020; 81:490-506. [PMID: 32628805 DOI: 10.1002/dneu.22771] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/28/2020] [Accepted: 06/12/2020] [Indexed: 12/11/2022]
Abstract
Axons share a close relationship with Schwann cells, their glial partners in peripheral nerves. An intricate axo-glia network of signals and bioactive molecules regulates the major aspects of nerve development and normal functioning of the peripheral nervous system. Disruptions to these complex axo-glial interactions can have serious neurological consequences, as typically seen in injured nerves. Recent studies in inherited neuropathies have demonstrated that damage to one of the partners in this symbiotic unit ultimately leads to impairment of the other partner, emphasizing the bidirectional influence of axon to glia and glia to axon signaling in these diseases. After physical trauma to nerves, dramatic alterations in the architecture and signaling environment of peripheral nerves take place. Here, axons and Schwann cells respond adaptively to these perturbations and change the nature of their reciprocal interactions, thereby driving the remodeling and regeneration of peripheral nerves. In this review, we focus on the nature and importance of axon-glia interactions in injured nerves, both for the reshaping and repair of nerves after trauma, and in driving pathology in inherited peripheral neuropathies.
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Affiliation(s)
- Ruth M Stassart
- Department of Neuropathology, University Clinic Leipzig, Leipzig, Germany
| | - Ashwin Woodhoo
- Nerve Disorders Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia, Spain.,IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
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50
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Gao G, He J, Luo Y, Sun Y, Zhou Y, Zhang J, Xing Y, Dai J. Axonopathy Likely Initiates Neuropathological Processes Via a Mechanism of Axonal Leakage in Alzheimer's Mouse Models. Curr Mol Med 2020; 19:183-195. [PMID: 30961496 DOI: 10.2174/1566524019666190405174908] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 03/14/2019] [Accepted: 03/15/2019] [Indexed: 12/31/2022]
Abstract
BACKGROUND The formation of hyperphosphorylated tau and the production of β-amyloid are thought to be critical steps contributing to the pathological mechanisms in Alzheimer's disease (AD). However, there has been a long-lasting debate over their importance in the onset of AD. Recent studies have demonstrated that axonopathy is considered as an early neuropathological change of AD. However, the exact relationship between the development of axonopathy and the classic neuropathological changes such as senile plaques (SPs) and neurofibrillary tangles (NFTs) is unclear. OBJECTIVE The aim of this study was to investigate whether the formation of SPs and NFTs is associated with the development of axonal leakage. METHOD AND RESULTS Here we show that the formation and development of axonal leakage - a novel axonopathy is an age-dependent process, accompanied by swellings of axons and varicosities and associated with chronic oxidative stress induced by thiamine deficient (TD) diet in Kunming mice. In an APP/PS1 transgenic mouse model of AD, axonal leakage appears at 3 months, becomes more obvious at 6 months and severe, beyond 1 year. We also show that slight axonal leakage is related to the formation of hyperphosphorylated tau, but not plaques, and that only severe axonal leakage accompanied by the extensive swollen axons and varicosities, and overproduction of β-amyloid leads to the formation of SPs and hyperphosphorylated tau. CONCLUSION These data provide an explanation of the common origin and development of SPs and NFTs, and suggest that axonal leakage might be a key event in the development of the neuropathological processes in AD.
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Affiliation(s)
- Ge Gao
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan, China
| | - Jing He
- Wuhan Institute for Neuroscience and Neuroengineering, South-Central University for Nationalities, Wuhan, Hubei, China.,Clinical Laboratory of the Second Affiliated Hospital, Hunan University of Chinese Medicine, Changsha, China
| | - Yi Luo
- Wuhan Institute for Neuroscience and Neuroengineering, South-Central University for Nationalities, Wuhan, Hubei, China.,Clinical Laboratory of Zhongnan Hospital, Wuhan University, Wuhan, Hubei, China
| | - Yan Sun
- Wuhan Institute for Neuroscience and Neuroengineering, South-Central University for Nationalities, Wuhan, Hubei, China.,The College of Life Sciences, South-Central University for Nationalities, Wuhan, Hubei, China
| | - Yanping Zhou
- Wuhan Institute for Neuroscience and Neuroengineering, South-Central University for Nationalities, Wuhan, Hubei, China.,Department of Pathophysiology, Guangxi University of Chinese Medicine, Nanning, Guangxi, China
| | - Junxia Zhang
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan, China.,Department of Anatomy, Histology and Embryology, Henan University of Chinese Medicine, Zhengzhou, Henan, China
| | - Ying Xing
- School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan, China
| | - Jiapei Dai
- Wuhan Institute for Neuroscience and Neuroengineering, South-Central University for Nationalities, Wuhan, Hubei, China.,The College of Life Sciences, South-Central University for Nationalities, Wuhan, Hubei, China
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