101
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Fukuda Y, Li Y, Segal RA. A Mechanistic Understanding of Axon Degeneration in Chemotherapy-Induced Peripheral Neuropathy. Front Neurosci 2017; 11:481. [PMID: 28912674 PMCID: PMC5583221 DOI: 10.3389/fnins.2017.00481] [Citation(s) in RCA: 124] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 08/14/2017] [Indexed: 12/12/2022] Open
Abstract
Chemotherapeutic agents cause many short and long term toxic side effects to peripheral nervous system (PNS) that drastically alter quality of life. Chemotherapy-induced peripheral neuropathy (CIPN) is a common and enduring disorder caused by several anti-neoplastic agents. CIPN typically presents with neuropathic pain, numbness of distal extremities, and/or oversensitivity to thermal or mechanical stimuli. This adverse side effect often requires a reduction in chemotherapy dosage or even discontinuation of treatment. Currently there are no effective treatment options for CIPN. While the underlying mechanisms for CIPN are not understood, current data identify a “dying back” axon degeneration of distal nerve endings as the major pathology in this disorder. Therefore, mechanistic understanding of axon degeneration will provide insights into the pathway and molecular players responsible for CIPN. Here, we review recent findings that expand our understanding of the pathogenesis of CIPN and discuss pathways that may be shared with the axonal degeneration that occurs during developmental axon pruning and during injury-induced Wallerian degeneration. These mechanistic insights provide new avenues for development of therapies to prevent or treat CIPN.
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Affiliation(s)
- Yusuke Fukuda
- Department of Neurobiology, Harvard Medical SchoolBoston, MA, United States.,Department of Cancer Biology, Dana-Farber Cancer InstituteBoston, MA, United States
| | - Yihang Li
- Department of Neurobiology, Harvard Medical SchoolBoston, MA, United States.,Department of Cancer Biology, Dana-Farber Cancer InstituteBoston, MA, United States
| | - Rosalind A Segal
- Department of Neurobiology, Harvard Medical SchoolBoston, MA, United States.,Department of Cancer Biology, Dana-Farber Cancer InstituteBoston, MA, United States
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102
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Kumamoto K, Iguchi T, Ishida R, Uemura T, Sato M, Hirotsune S. Developmental downregulation of LIS1 expression limits axonal extension and allows axon pruning. Biol Open 2017. [PMID: 28630356 PMCID: PMC5550919 DOI: 10.1242/bio.025999] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The robust axonal growth and regenerative capacities of young neurons decrease substantially with age. This developmental downregulation of axonal growth may facilitate axonal pruning and neural circuit formation but limits functional recovery following nerve damage. While external factors influencing axonal growth have been extensively investigated, relatively little is known about the intrinsic molecular changes underlying the age-dependent reduction in regeneration capacity. We report that developmental downregulation of LIS1 is responsible for the decreased axonal extension capacity of mature dorsal root ganglion (DRG) neurons. In contrast, exogenous LIS1 expression or endogenous LIS1 augmentation by calpain inhibition restored axonal extension capacity in mature DRG neurons and facilitated regeneration of the damaged sciatic nerve. The insulator protein CTCF suppressed LIS1 expression in mature DRG neurons, and this reduction resulted in excessive accumulation of phosphoactivated GSK-3β at the axon tip, causing failure of the axonal extension. Conversely, sustained LIS1 expression inhibited developmental axon pruning in the mammillary body. Thus, LIS1 regulation may coordinate the balance between axonal growth and pruning during maturation of neuronal circuits. Summary: Developmental downregulation of LIS1 coordinates the balance between axonal elongation and pruning, which is essential for proper neuronal circuit formation but limits nerve regeneration.
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Affiliation(s)
- Kanako Kumamoto
- Department of Genetic Disease Research, Osaka City University, Graduate School of Medicine, Asahi-machi 1-4-3, Abeno, Osaka 545-8585, Japan
| | - Tokuichi Iguchi
- Department of Anatomy and Neuroscience, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
| | - Ryuichi Ishida
- Department of Genetic Disease Research, Osaka City University, Graduate School of Medicine, Asahi-machi 1-4-3, Abeno, Osaka 545-8585, Japan
| | - Takuya Uemura
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Asahi-machi 1-4-3, Abeno, Osaka 545-8585, Japan
| | - Makoto Sato
- Department of Anatomy and Neuroscience, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan.,Research Center for Child Mental Development, University of Fukui, Fukui 910-1193, Japan.,United Graduate School of Child Development, Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University, and University of Fukui, Osaka 565-0871, Japan
| | - Shinji Hirotsune
- Department of Genetic Disease Research, Osaka City University, Graduate School of Medicine, Asahi-machi 1-4-3, Abeno, Osaka 545-8585, Japan
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103
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Schaefer KA, Toral MA, Velez G, Cox AJ, Baker SA, Borcherding NC, Colgan DF, Bondada V, Mashburn CB, Yu CG, Geddes JW, Tsang SH, Bassuk AG, Mahajan VB. Calpain-5 Expression in the Retina Localizes to Photoreceptor Synapses. Invest Ophthalmol Vis Sci 2017; 57:2509-21. [PMID: 27152965 PMCID: PMC4868102 DOI: 10.1167/iovs.15-18680] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Purpose We characterize calpain-5 (CAPN5) expression in retinal and neuronal subcellular compartments. Methods CAPN5 gene variants were classified using the exome variant server, and RNA-sequencing was used to compare expression of CAPN5 mRNA in the mouse and human retina and in retinoblastoma cells. Expression of CAPN5 protein was ascertained in humans and mice in silico, in mouse retina by immunohistochemistry, and in neuronal cancer cell lines and fractionated central nervous system tissue extracts by Western analysis with eight antibodies targeting different CAPN5 regions. Results Most CAPN5 genetic variation occurs outside its protease core; and searches of cancer and epilepsy/autism genetic databases found no variants similar to hyperactivating retinal disease alleles. The mouse retina expressed one transcript for CAPN5 plus those of nine other calpains, similar to the human retina. In Y79 retinoblastoma cells, the level of CAPN5 transcript was very low. Immunohistochemistry detected CAPN5 expression in the inner and outer nuclear layers and at synapses in the outer plexiform layer. Western analysis of fractionated retinal extracts confirmed CAPN5 synapse localization. Western blots of fractionated brain neuronal extracts revealed distinct subcellular patterns and the potential presence of autoproteolytic CAPN5 domains. Conclusions CAPN5 is moderately expressed in the retina and, despite higher expression in other tissues, hyperactive disease mutants of CAPN5 only manifest as eye disease. At the cellular level, CAPN5 is expressed in several different functional compartments. CAPN5 localization at the photoreceptor synapse and with mitochondria explains the neural circuitry phenotype in human CAPN5 disease alleles.
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Affiliation(s)
- Kellie A Schaefer
- Omics Laboratory, University of Iowa, Iowa City, Iowa, United States 2Department of Ophthalmology & Visual Sciences, University of Iowa, Iowa City, Iowa, United States
| | - Marcus A Toral
- Omics Laboratory, University of Iowa, Iowa City, Iowa, United States 2Department of Ophthalmology & Visual Sciences, University of Iowa, Iowa City, Iowa, United States 3Medical Scientist Training Program, University of Iowa, Iowa City, Iowa, United States
| | - Gabriel Velez
- Omics Laboratory, University of Iowa, Iowa City, Iowa, United States 2Department of Ophthalmology & Visual Sciences, University of Iowa, Iowa City, Iowa, United States 3Medical Scientist Training Program, University of Iowa, Iowa City, Iowa, United States
| | - Allison J Cox
- Department of Pediatrics, University of Iowa, Iowa City, Iowa, United States
| | - Sheila A Baker
- Department of Ophthalmology & Visual Sciences, University of Iowa, Iowa City, Iowa, United States 5Department of Biochemistry, University of Iowa, Iowa City, Iowa, United States
| | - Nicholas C Borcherding
- Omics Laboratory, University of Iowa, Iowa City, Iowa, United States 3Medical Scientist Training Program, University of Iowa, Iowa City, Iowa, United States
| | - Diana F Colgan
- Omics Laboratory, University of Iowa, Iowa City, Iowa, United States 2Department of Ophthalmology & Visual Sciences, University of Iowa, Iowa City, Iowa, United States
| | - Vimala Bondada
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, United States
| | - Charles B Mashburn
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, United States
| | - Chen-Guang Yu
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, United States
| | - James W Geddes
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, United States
| | - Stephen H Tsang
- Barbara & Donald Jonas Stem Cell Laboratory, and Bernard & Shirlee Brown Glaucoma Laboratory, Department of Pathology & Cell Biology, Institute of Human Nutrition, College of Physicians and Surgeons, Columbia University, New York, New York, United States
| | - Alexander G Bassuk
- Department of Pediatrics, University of Iowa, Iowa City, Iowa, United States 9Neurology, University of Iowa, Iowa City, Iowa, United States
| | - Vinit B Mahajan
- Omics Laboratory, University of Iowa, Iowa City, Iowa, United States 2Department of Ophthalmology & Visual Sciences, University of Iowa, Iowa City, Iowa, United States
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104
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Gu Y, Jukkola P, Wang Q, Esparza T, Zhao Y, Brody D, Gu C. Polarity of varicosity initiation in central neuron mechanosensation. J Cell Biol 2017; 216:2179-2199. [PMID: 28606925 PMCID: PMC5496611 DOI: 10.1083/jcb.201606065] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 01/17/2017] [Accepted: 04/20/2017] [Indexed: 12/22/2022] Open
Abstract
Little is known about mechanical regulation of morphological and functional polarity of central neurons. In this study, we report that mechanical stress specifically induces varicosities in the axons but not the dendrites of central neurons by activating TRPV4, a Ca2+/Na+-permeable mechanosensitive channel. This process is unexpectedly rapid and reversible, consistent with the formation of axonal varicosities in vivo induced by mechanical impact in a mouse model of mild traumatic brain injury. In contrast, prolonged stimulation of glutamate receptors induces varicosities in dendrites but not in axons. We further show that axonal varicosities are induced by persistent Ca2+ increase, disassembled microtubules (MTs), and subsequently reversible disruption of axonal transport, and are regulated by stable tubulin-only polypeptide, an MT-associated protein. Finally, axonal varicosity initiation can trigger action potentials to antidromically propagate to the soma in retrograde signaling. Therefore, our study demonstrates a new feature of neuronal polarity: axons and dendrites preferentially respond to physical and chemical stresses, respectively.
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Affiliation(s)
- Yuanzheng Gu
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH
| | - Peter Jukkola
- Biomedical Sciences Graduate Program, The Ohio State University, Columbus, OH
| | - Qian Wang
- Biomedical Engineering Department, The Ohio State University, Columbus, OH
| | - Thomas Esparza
- Department of Neurology, Washington University, St. Louis, MO
| | - Yi Zhao
- Biomedical Engineering Department, The Ohio State University, Columbus, OH
| | - David Brody
- Department of Neurology, Washington University, St. Louis, MO
| | - Chen Gu
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH .,Biomedical Sciences Graduate Program, The Ohio State University, Columbus, OH
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105
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Larhammar M, Huntwork-Rodriguez S, Jiang Z, Solanoy H, Sengupta Ghosh A, Wang B, Kaminker JS, Huang K, Eastham-Anderson J, Siu M, Modrusan Z, Farley MM, Tessier-Lavigne M, Lewcock JW, Watkins TA. Dual leucine zipper kinase-dependent PERK activation contributes to neuronal degeneration following insult. eLife 2017; 6. [PMID: 28440222 PMCID: PMC5404924 DOI: 10.7554/elife.20725] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 03/20/2017] [Indexed: 01/24/2023] Open
Abstract
The PKR-like endoplasmic reticulum kinase (PERK) arm of the Integrated Stress Response (ISR) is implicated in neurodegenerative disease, although the regulators and consequences of PERK activation following neuronal injury are poorly understood. Here we show that PERK signaling is a component of the mouse MAP kinase neuronal stress response controlled by the Dual Leucine Zipper Kinase (DLK) and contributes to DLK-mediated neurodegeneration. We find that DLK-activating insults ranging from nerve injury to neurotrophin deprivation result in both c-Jun N-terminal Kinase (JNK) signaling and the PERK- and ISR-dependent upregulation of the Activating Transcription Factor 4 (ATF4). Disruption of PERK signaling delays neurodegeneration without reducing JNK signaling. Furthermore, DLK is both sufficient for PERK activation and necessary for engaging the ISR subsequent to JNK-mediated retrograde injury signaling. These findings identify DLK as a central regulator of not only JNK but also PERK stress signaling in neurons, with both pathways contributing to neurodegeneration.
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Affiliation(s)
- Martin Larhammar
- Department of Neuroscience, Genentech, Inc., San Francisco, United States
| | | | - Zhiyu Jiang
- Department of Neuroscience, Genentech, Inc., San Francisco, United States
| | - Hilda Solanoy
- Department of Neuroscience, Genentech, Inc., San Francisco, United States
| | | | - Bei Wang
- Department of Neuroscience, Genentech, Inc., San Francisco, United States
| | | | - Kevin Huang
- Bioinformatics, Genentech, Inc., San Francisco, United States
| | | | - Michael Siu
- Discovery Chemistry, Genentech, Inc., San Francisco, United States
| | - Zora Modrusan
- Molecular Biology, Genentech, Inc., San Francisco, United States
| | - Madeline M Farley
- Department of Neurosurgery, Baylor College of Medicine, Houston, Texas
| | - Marc Tessier-Lavigne
- Department of Neuroscience, Genentech, Inc., San Francisco, United States.,Laboratory of Brain Development and Repair, The Rockefeller University, New York, United States
| | - Joseph W Lewcock
- Department of Neuroscience, Genentech, Inc., San Francisco, United States
| | - Trent A Watkins
- Department of Neuroscience, Genentech, Inc., San Francisco, United States.,Department of Neurosurgery, Baylor College of Medicine, Houston, Texas.,OMNI Biomarkers Development, Genentech, Inc., San Francisco, United States
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106
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Drerup CM, Herbert AL, Monk KR, Nechiporuk AV. Regulation of mitochondria-dynactin interaction and mitochondrial retrograde transport in axons. eLife 2017; 6:22234. [PMID: 28414272 PMCID: PMC5413347 DOI: 10.7554/elife.22234] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Accepted: 04/12/2017] [Indexed: 12/11/2022] Open
Abstract
Mitochondrial transport in axons is critical for neural circuit health and function. While several proteins have been found that modulate bidirectional mitochondrial motility, factors that regulate unidirectional mitochondrial transport have been harder to identify. In a genetic screen, we found a zebrafish strain in which mitochondria fail to attach to the dynein retrograde motor. This strain carries a loss-of-function mutation in actr10, a member of the dynein-associated complex dynactin. The abnormal axon morphology and mitochondrial retrograde transport defects observed in actr10 mutants are distinct from dynein and dynactin mutant axonal phenotypes. In addition, Actr10 lacking the dynactin binding domain maintains its ability to bind mitochondria, arguing for a role for Actr10 in dynactin-mitochondria interaction. Finally, genetic interaction studies implicated Drp1 as a partner in Actr10-dependent mitochondrial retrograde transport. Together, this work identifies Actr10 as a factor necessary for dynactin-mitochondria interaction, enhancing our understanding of how mitochondria properly localize in axons. DOI:http://dx.doi.org/10.7554/eLife.22234.001
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Affiliation(s)
- Catherine M Drerup
- Department of Cell, Developmental and Cancer Biology, Oregon Health & Science University, Portland, United States.,National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
| | - Amy L Herbert
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, United States
| | - Kelly R Monk
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, United States
| | - Alex V Nechiporuk
- Department of Cell, Developmental and Cancer Biology, Oregon Health & Science University, Portland, United States
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107
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Wang S, Wang S, Asgar J, Joseph J, Ro JY, Wei F, Campbell JN, Chung MK. Ca 2+ and calpain mediate capsaicin-induced ablation of axonal terminals expressing transient receptor potential vanilloid 1. J Biol Chem 2017; 292:8291-8303. [PMID: 28360106 DOI: 10.1074/jbc.m117.778290] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 03/28/2017] [Indexed: 01/01/2023] Open
Abstract
Capsaicin is an ingredient in spicy peppers that produces burning pain by activating transient receptor potential vanilloid 1 (TRPV1), a Ca2+-permeable ion channel in nociceptors. Capsaicin has also been used as an analgesic, and its topical administration is approved for the treatment of certain pain conditions. The mechanisms underlying capsaicin-induced analgesia likely involve reversible ablation of nociceptor terminals. However, the mechanisms underlying these effects are not well understood. To visualize TRPV1-lineage axons, a genetically engineered mouse model was used in which a fluorophore is expressed under the TRPV1 promoter. Using a combination of these TRPV1-lineage reporter mice and primary afferent cultures, we monitored capsaicin-induced effects on afferent terminals in real time. We found that Ca2+ influx through TRPV1 is necessary for capsaicin-induced ablation of nociceptive terminals. Although capsaicin-induced mitochondrial Ca2+ uptake was TRPV1-dependent, dissipation of the mitochondrial membrane potential, inhibition of the mitochondrial transition permeability pore, and scavengers of reactive oxygen species did not attenuate capsaicin-induced ablation. In contrast, MDL28170, an inhibitor of the Ca2+-dependent protease calpain, diminished ablation. Furthermore, overexpression of calpastatin, an endogenous inhibitor of calpain, or knockdown of calpain 2 also decreased ablation. Quantitative assessment of TRPV1-lineage afferents in the epidermis of the hind paws of the reporter mice showed that EGTA and MDL28170 diminished capsaicin-induced ablation. Moreover, MDL28170 prevented capsaicin-induced thermal hypoalgesia. These results suggest that TRPV1/Ca2+/calpain-dependent signaling plays a dominant role in capsaicin-induced ablation of nociceptive terminals and further our understanding of the molecular mechanisms underlying the effects of capsaicin on nociceptors.
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Affiliation(s)
- Sheng Wang
- Department of Neural and Pain Sciences, School of Dentistry, Program in Neuroscience, Center to Advance Chronic Pain Research, University of Maryland, Baltimore, Maryland 21201
| | - Sen Wang
- Department of Neural and Pain Sciences, School of Dentistry, Program in Neuroscience, Center to Advance Chronic Pain Research, University of Maryland, Baltimore, Maryland 21201
| | - Jamila Asgar
- Department of Neural and Pain Sciences, School of Dentistry, Program in Neuroscience, Center to Advance Chronic Pain Research, University of Maryland, Baltimore, Maryland 21201
| | - John Joseph
- Department of Neural and Pain Sciences, School of Dentistry, Program in Neuroscience, Center to Advance Chronic Pain Research, University of Maryland, Baltimore, Maryland 21201
| | - Jin Y Ro
- Department of Neural and Pain Sciences, School of Dentistry, Program in Neuroscience, Center to Advance Chronic Pain Research, University of Maryland, Baltimore, Maryland 21201
| | - Feng Wei
- Department of Neural and Pain Sciences, School of Dentistry, Program in Neuroscience, Center to Advance Chronic Pain Research, University of Maryland, Baltimore, Maryland 21201
| | | | - Man-Kyo Chung
- Department of Neural and Pain Sciences, School of Dentistry, Program in Neuroscience, Center to Advance Chronic Pain Research, University of Maryland, Baltimore, Maryland 21201.
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108
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Inman DM, Harun-Or-Rashid M. Metabolic Vulnerability in the Neurodegenerative Disease Glaucoma. Front Neurosci 2017; 11:146. [PMID: 28424571 PMCID: PMC5371671 DOI: 10.3389/fnins.2017.00146] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 03/08/2017] [Indexed: 12/14/2022] Open
Abstract
Axons can be several orders of magnitude longer than neural somas, presenting logistical difficulties in cargo trafficking and structural maintenance. Keeping the axon compartment well supplied with energy also presents a considerable challenge; even seemingly subtle modifications of metabolism can result in functional deficits and degeneration. Axons require a great deal of energy, up to 70% of all energy used by a neuron, just to maintain the resting membrane potential. Axonal energy, in the form of ATP, is generated primarily through oxidative phosphorylation in the mitochondria. In addition, glial cells contribute metabolic intermediates to axons at moments of high activity or according to need. Recent evidence suggests energy disruption is an early contributor to pathology in a wide variety of neurodegenerative disorders characterized by axonopathy. However, the degree to which the energy disruption is intrinsic to the axon vs. associated glia is not clear. This paper will review the role of energy availability and utilization in axon degeneration in glaucoma, a chronic axonopathy of the retinal projection.
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Affiliation(s)
- Denise M Inman
- Department of Pharmaceutical Sciences, Northeast Ohio Medical UniversityRootstown, OH, USA
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109
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Son AI, Fu X, Suto F, Liu JS, Hashimoto-Torii K, Torii M. Proteome dynamics during postnatal mouse corpus callosum development. Sci Rep 2017; 7:45359. [PMID: 28349996 PMCID: PMC5368975 DOI: 10.1038/srep45359] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 02/27/2017] [Indexed: 02/08/2023] Open
Abstract
Formation of cortical connections requires the precise coordination of numerous discrete phases. This is particularly significant with regard to the corpus callosum, whose development undergoes several dynamic stages including the crossing of axon projections, elimination of exuberant projections, and myelination of established tracts. To comprehensively characterize the molecular events in this dynamic process, we set to determine the distinct temporal expression of proteins regulating the formation of the corpus callosum and their respective developmental functions. Mass spectrometry-based proteomic profiling was performed on early postnatal mouse corpus callosi, for which limited evidence has been obtained previously, using stable isotope of labeled amino acids in mammals (SILAM). The analyzed corpus callosi had distinct proteomic profiles depending on age, indicating rapid progression of specific molecular events during this period. The proteomic profiles were then segregated into five separate clusters, each with distinct trajectories relevant to their intended developmental functions. Our analysis both confirms many previously-identified proteins in aspects of corpus callosum development, and identifies new candidates in understudied areas of development including callosal axon refinement. We present a valuable resource for identifying new proteins integral to corpus callosum development that will provide new insights into the development and diseases afflicting this structure.
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Affiliation(s)
- Alexander I Son
- Center for Neuroscience Research, Children's Research Institute, Children's National Medical Center, Washington, DC 20010, USA
| | - Xiaoqin Fu
- Center for Neuroscience Research, Children's Research Institute, Children's National Medical Center, Washington, DC 20010, USA
| | - Fumikazu Suto
- Department of Ultrastructural Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo 187-8502, Japan
| | - Judy S Liu
- Center for Neuroscience Research, Children's Research Institute, Children's National Medical Center, Washington, DC 20010, USA.,Department of Pediatrics, Pharmacology and Physiology, School of Medicine and Health Sciences, The George Washington University, Washington, DC 20052, USA
| | - Kazue Hashimoto-Torii
- Center for Neuroscience Research, Children's Research Institute, Children's National Medical Center, Washington, DC 20010, USA.,Department of Pediatrics, Pharmacology and Physiology, School of Medicine and Health Sciences, The George Washington University, Washington, DC 20052, USA.,Department of Neurobiology and Kavli Institute for Neuroscience, School of Medicine, Yale University, New Haven, CT 06510, USA
| | - Masaaki Torii
- Center for Neuroscience Research, Children's Research Institute, Children's National Medical Center, Washington, DC 20010, USA.,Department of Pediatrics, Pharmacology and Physiology, School of Medicine and Health Sciences, The George Washington University, Washington, DC 20052, USA.,Department of Neurobiology and Kavli Institute for Neuroscience, School of Medicine, Yale University, New Haven, CT 06510, USA
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110
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Gamage KK, Cheng I, Park RE, Karim MS, Edamura K, Hughes C, Spano AJ, Erisir A, Deppmann CD. Death Receptor 6 Promotes Wallerian Degeneration in Peripheral Axons. Curr Biol 2017; 27:890-896. [PMID: 28285993 DOI: 10.1016/j.cub.2017.01.062] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 12/19/2016] [Accepted: 01/30/2017] [Indexed: 11/17/2022]
Abstract
Axon degeneration during development is required to sculpt a functional nervous system and is also a hallmark of pathological insult, such as injury [1, 2]. Despite similar morphological characteristics, very little overlap in molecular mechanisms has been reported between pathological and developmental degeneration [3-5]. In the peripheral nervous system (PNS), developmental axon pruning relies on receptor-mediated extrinsic degeneration mechanisms to determine which axons are maintained or degenerated [5-7]. Receptors have not been implicated in Wallerian axon degeneration; instead, axon autonomous, intrinsic mechanisms are thought to be the primary driver for this type of axon disintegration [8-10]. Here we survey the role of neuronally expressed, paralogous tumor necrosis factor receptor super family (TNFRSF) members in Wallerian degeneration. We find that an orphan receptor, death receptor 6 (DR6), is required to drive axon degeneration after axotomy in sympathetic and sensory neurons cultured in microfluidic devices. We sought to validate these in vitro findings in vivo using a transected sciatic nerve model. Consistent with the in vitro findings, DR6-/- animals displayed preserved axons up to 4 weeks after injury. In contrast to phenotypes observed in Wlds and Sarm1-/- mice, preserved axons in DR6-/- animals display profound myelin remodeling. This indicates that deterioration of axons and myelin after axotomy are mechanistically distinct processes. Finally, we find that JNK signaling after injury requires DR6, suggesting a link between this novel extrinsic pathway and the axon autonomous, intrinsic pathways that have become established for Wallerian degeneration.
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Affiliation(s)
- Kanchana K Gamage
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA
| | - Irene Cheng
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA; Neuroscience Graduate Program, University of Virginia, Charlottesville, VA 22903, USA
| | - Rachel E Park
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA
| | - Mardeen S Karim
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA
| | - Kazusa Edamura
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA
| | - Christopher Hughes
- Department of Physics and Astronomy, James Madison University, Harrisonburg, VA 22807, USA
| | - Anthony J Spano
- Department of Biology, University of Virginia, Charlottesville, VA 22903, USA
| | - Alev Erisir
- Department of Psychology, University of Virginia, Charlottesville, VA 22903, USA
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111
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Holland SM, Thomas GM. Roles of palmitoylation in axon growth, degeneration and regeneration. J Neurosci Res 2017; 95:1528-1539. [PMID: 28150429 DOI: 10.1002/jnr.24003] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 11/09/2016] [Accepted: 11/28/2016] [Indexed: 12/11/2022]
Abstract
The protein-lipid modification palmitoylation plays important roles in neurons, but most attention has focused on roles of this modification in the regulation of mature pre- and post-synapses. However, exciting recent findings suggest that palmitoylation is also critical for both the growth and integrity of neuronal axons and plays previously unappreciated roles in conveying axonal anterograde and retrograde signals. Here we review these emerging roles for palmitoylation in the regulation of axons in health and disease. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Sabrina M Holland
- Shriners Hospitals Pediatric Research Center (Center for Neurorehabilitation and Neural Repair)
| | - Gareth M Thomas
- Shriners Hospitals Pediatric Research Center (Center for Neurorehabilitation and Neural Repair).,Department of Anatomy and Cell Biology, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, Philadelphia, PA, 19140
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112
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Abstract
Axonal degeneration is a pivotal feature of many neurodegenerative conditions and substantially accounts for neurological morbidity. A widely used experimental model to study the mechanisms of axonal degeneration is Wallerian degeneration (WD), which occurs after acute axonal injury. In the peripheral nervous system (PNS), WD is characterized by swift dismantling and clearance of injured axons with their myelin sheaths. This is a prerequisite for successful axonal regeneration. In the central nervous system (CNS), WD is much slower, which significantly contributes to failed axonal regeneration. Although it is well-documented that Schwann cells (SCs) have a critical role in the regenerative potential of the PNS, to date we have only scarce knowledge as to how SCs ‘sense’ axonal injury and immediately respond to it. In this regard, it remains unknown as to whether SCs play the role of a passive bystander or an active director during the execution of the highly orchestrated disintegration program of axons. Older reports, together with more recent studies, suggest that SCs mount dynamic injury responses minutes after axonal injury, long before axonal breakdown occurs. The swift SC response to axonal injury could play either a pro-degenerative role, or alternatively a supportive role, to the integrity of distressed axons that have not yet committed to degenerate. Indeed, supporting the latter concept, recent findings in a chronic PNS neurodegeneration model indicate that deactivation of a key molecule promoting SC injury responses exacerbates axonal loss. If this holds true in a broader spectrum of conditions, it may provide the grounds for the development of new glia-centric therapeutic approaches to counteract axonal loss.
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Affiliation(s)
- Keit Men Wong
- Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Elisabetta Babetto
- Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA.,Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Bogdan Beirowski
- Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA.,Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
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113
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Gordon T, Borschel GH. The use of the rat as a model for studying peripheral nerve regeneration and sprouting after complete and partial nerve injuries. Exp Neurol 2017; 287:331-347. [DOI: 10.1016/j.expneurol.2016.01.014] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 01/14/2016] [Accepted: 01/15/2016] [Indexed: 02/06/2023]
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114
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Sedmak G, Jovanov-Milošević N, Puskarjov M, Ulamec M, Krušlin B, Kaila K, Judaš M. Developmental Expression Patterns of KCC2 and Functionally Associated Molecules in the Human Brain. Cereb Cortex 2016; 26:4574-4589. [PMID: 26428952 DOI: 10.1093/cercor/bhv218] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Work on rodents demonstrated that steep upregulation of KCC2, a neuron-specific Cl- extruder of cation-chloride cotransporter (CCC) family, commences in supraspinal structures at around birth, leading to establishment of hyperpolarizing GABAergic responses. We describe spatiotemporal expression profiles of the entire CCC family in human brain. KCC2 mRNA was observed already at 10th postconceptional week (PCW) in amygdala, cerebellum, and thalamus. KCC2-immunoreactive (KCC2-ir) neurons were abundant in subplate at 18 PCW. By 25 PCW, numerous subplate and cortical plate neurons became KCC2-ir. The mRNA expression profiles of α- and β-isoforms of Na-K ATPase, which fuels cation-chloride cotransport, as well of tropomyosin receptor kinase B (TrkB), which promotes developmental upregulation of KCC2, were consistent with data from studies on rodents about their interactions with KCC2. Thus, in human brain, expression of KCC2 and its functionally associated proteins begins in early fetal period. Our work facilitates translation of results on CCC functions from animal studies to human and refutes the view that poor efficacy of anticonvulsants in the term human neonate is attributable to the lack of KCC2. We propose that perinatally low threshold for activation of Ca2+-dependent protease calpain renders neonates susceptible to downregulation of KCC2 by traumatic events, such as perinatal hypoxia ischemia.
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Affiliation(s)
| | | | - Martin Puskarjov
- Department of Biosciences and Neuroscience Center, University of Helsinki, Viikinkaari 1, Helsinki FI-00014, Finland
| | - Monika Ulamec
- Department of Pathology, Clinical Hospital Center Sisters of Mercy, University of Zagreb School of Medicine, Zagreb 10 000, Croatia
| | - Božo Krušlin
- Department of Pathology, Clinical Hospital Center Sisters of Mercy, University of Zagreb School of Medicine, Zagreb 10 000, Croatia
| | - Kai Kaila
- Department of Biosciences and Neuroscience Center, University of Helsinki, Viikinkaari 1, Helsinki FI-00014, Finland
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115
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Zhang JN, Michel U, Lenz C, Friedel CC, Köster S, d’Hedouville Z, Tönges L, Urlaub H, Bähr M, Lingor P, Koch JC. Calpain-mediated cleavage of collapsin response mediator protein-2 drives acute axonal degeneration. Sci Rep 2016; 6:37050. [PMID: 27845394 PMCID: PMC5109185 DOI: 10.1038/srep37050] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 10/24/2016] [Indexed: 01/25/2023] Open
Abstract
Axonal degeneration is a key initiating event in many neurological diseases. Focal lesions to axons result in a rapid disintegration of the perilesional axon by acute axonal degeneration (AAD) within several hours. However, the underlying molecular mechanisms of AAD are only incompletely understood. Here, we studied AAD in vivo through live-imaging of the rat optic nerve and in vitro in primary rat cortical neurons in microfluidic chambers. We found that calpain is activated early during AAD of the optic nerve and that calpain inhibition completely inhibits axonal fragmentation on the proximal side of the crush while it attenuates AAD on the distal side. A screening of calpain targets revealed that collapsin response mediator protein-2 (CRMP2) is a main downstream target of calpain activation in AAD. CRMP2-overexpression delayed bulb formation and rescued impairment of axonal mitochondrial transport after axotomy in vitro. In vivo, CRMP2-overexpression effectively protected the proximal axon from fragmentation within 6 hours after crush. Finally, a proteomic analysis of the optic nerve was performed at 6 hours after crush, which identified further proteins regulated during AAD, including several interactors of CRMP2. These findings reveal CRMP2 as an important mediator of AAD and define it as a putative therapeutic target.
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Affiliation(s)
- Jian-Nan Zhang
- Department of Neurology, University Medicine Göttingen, 37075 Göttingen, Germany
| | - Uwe Michel
- Department of Neurology, University Medicine Göttingen, 37075 Göttingen, Germany
| | - Christof Lenz
- Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
- Institute of Clinical Chemistry, University Medicine Göttingen, 37075 Göttingen, Germany
| | | | - Sarah Köster
- Institute for X-Ray Physics, Georg-August-University Göttingen, 37077 Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), 37075 Göttingen, Germany
| | - Zara d’Hedouville
- Department of Neurology, University Medicine Göttingen, 37075 Göttingen, Germany
| | - Lars Tönges
- Department of Neurology, University Medicine Göttingen, 37075 Göttingen, Germany
- Department of Neurology, Ruhr-University Bochum, St. Josef-Hospital, 44791 Bochum, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany
- Institute of Clinical Chemistry, University Medicine Göttingen, 37075 Göttingen, Germany
| | - Mathias Bähr
- Department of Neurology, University Medicine Göttingen, 37075 Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), 37075 Göttingen, Germany
| | - Paul Lingor
- Department of Neurology, University Medicine Göttingen, 37075 Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), 37075 Göttingen, Germany
| | - Jan C. Koch
- Department of Neurology, University Medicine Göttingen, 37075 Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), 37075 Göttingen, Germany
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116
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Monitoring peripheral nerve degeneration in ALS by label-free stimulated Raman scattering imaging. Nat Commun 2016; 7:13283. [PMID: 27796305 PMCID: PMC5095598 DOI: 10.1038/ncomms13283] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 09/19/2016] [Indexed: 01/02/2023] Open
Abstract
The study of amyotrophic lateral sclerosis (ALS) and potential interventions would be facilitated if motor axon degeneration could be more readily visualized. Here we demonstrate that stimulated Raman scattering (SRS) microscopy could be used to sensitively monitor peripheral nerve degeneration in ALS mouse models and ALS autopsy materials. Three-dimensional imaging of pre-symptomatic SOD1 mouse models and data processing by a correlation-based algorithm revealed that significant degeneration of peripheral nerves could be detected coincidentally with the earliest detectable signs of muscle denervation and preceded physiologically measurable motor function decline. We also found that peripheral degeneration was an early event in FUS as well as C9ORF72 repeat expansion models of ALS, and that serial imaging allowed long-term observation of disease progression and drug effects in living animals. Our study demonstrates that SRS imaging is a sensitive and quantitative means of measuring disease progression, greatly facilitating future studies of disease mechanisms and candidate therapeutics.
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117
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FAIM-L regulation of XIAP degradation modulates Synaptic Long-Term Depression and Axon Degeneration. Sci Rep 2016; 6:35775. [PMID: 27767058 PMCID: PMC5073314 DOI: 10.1038/srep35775] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 10/05/2016] [Indexed: 12/19/2022] Open
Abstract
Caspases have recently emerged as key regulators of axonal pruning and degeneration and of long-term depression (LTD), a long-lasting form of synaptic plasticity. However, the mechanism underlying these functions remains unclear. In this context, XIAP has been shown to modulate these processes. The neuron-specific form of FAIM protein (FAIM-L) is a death receptor antagonist that stabilizes XIAP protein levels, thus preventing death receptor-induced neuronal apoptosis. Here we show that FAIM-L modulates synaptic transmission, prevents chemical-LTD induction in hippocampal neurons, and thwarts axon degeneration after nerve growth factor (NGF) withdrawal. Additionally, we demonstrate that the participation of FAIM-L in these two processes is dependent on its capacity to stabilize XIAP protein levels. Our data reveal FAIM-L as a regulator of axonal degeneration and synaptic plasticity.
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118
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Yaniv SP, Schuldiner O. A fly's view of neuronal remodeling. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2016; 5:618-35. [PMID: 27351747 PMCID: PMC5086085 DOI: 10.1002/wdev.241] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2016] [Revised: 04/10/2016] [Accepted: 04/18/2016] [Indexed: 11/17/2022]
Abstract
Developmental neuronal remodeling is a crucial step in sculpting the final and mature brain connectivity in both vertebrates and invertebrates. Remodeling includes degenerative events, such as neurite pruning, that may be followed by regeneration to form novel connections during normal development. Drosophila provides an excellent model to study both steps of remodeling since its nervous system undergoes massive and stereotypic remodeling during metamorphosis. Although pruning has been widely studied, our knowledge of the molecular and cellular mechanisms is far from complete. Our understanding of the processes underlying regrowth is even more fragmentary. In this review, we discuss recent progress by focusing on three groups of neurons that undergo stereotypic pruning and regrowth during metamorphosis, the mushroom body γ neurons, the dendritic arborization neurons and the crustacean cardioactive peptide peptidergic neurons. By comparing and contrasting the mechanisms involved in remodeling of these three neuronal types, we highlight the common themes and differences as well as raise key questions for future investigation in the field. WIREs Dev Biol 2016, 5:618–635. doi: 10.1002/wdev.241 For further resources related to this article, please visit the WIREs website
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Affiliation(s)
- Shiri P Yaniv
- Dept of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
| | - Oren Schuldiner
- Dept of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel
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119
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Curcio M, Salazar IL, Mele M, Canzoniero LMT, Duarte CB. Calpains and neuronal damage in the ischemic brain: The swiss knife in synaptic injury. Prog Neurobiol 2016; 143:1-35. [PMID: 27283248 DOI: 10.1016/j.pneurobio.2016.06.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 03/22/2016] [Accepted: 05/09/2016] [Indexed: 12/26/2022]
Abstract
The excessive extracellular accumulation of glutamate in the ischemic brain leads to an overactivation of glutamate receptors with consequent excitotoxic neuronal death. Neuronal demise is largely due to a sustained activation of NMDA receptors for glutamate, with a consequent increase in the intracellular Ca(2+) concentration and activation of calcium- dependent mechanisms. Calpains are a group of Ca(2+)-dependent proteases that truncate specific proteins, and some of the cleavage products remain in the cell, although with a distinct function. Numerous studies have shown pre- and post-synaptic effects of calpains on glutamatergic and GABAergic synapses, targeting membrane- associated proteins as well as intracellular proteins. The resulting changes in the presynaptic proteome alter neurotransmitter release, while the cleavage of postsynaptic proteins affects directly or indirectly the activity of neurotransmitter receptors and downstream mechanisms. These alterations also disturb the balance between excitatory and inhibitory neurotransmission in the brain, with an impact in neuronal demise. In this review we discuss the evidence pointing to a role for calpains in the dysregulation of excitatory and inhibitory synapses in brain ischemia, at the pre- and post-synaptic levels, as well as the functional consequences. Although targeting calpain-dependent mechanisms may constitute a good therapeutic approach for stroke, specific strategies should be developed to avoid non-specific effects given the important regulatory role played by these proteases under normal physiological conditions.
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Affiliation(s)
- Michele Curcio
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Ivan L Salazar
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; Doctoral Programme in Experimental Biology and Biomedicine, Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; Institute for Interdisciplinary Research, University of Coimbra (IIIUC), 3030-789 Coimbra, Portugal
| | - Miranda Mele
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | | | - Carlos B Duarte
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal.
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120
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Chang B, Quan Q, Lu S, Wang Y, Peng J. Molecular mechanisms in the initiation phase of Wallerian degeneration. Eur J Neurosci 2016; 44:2040-8. [PMID: 27062141 DOI: 10.1111/ejn.13250] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 04/06/2016] [Accepted: 04/06/2016] [Indexed: 12/20/2022]
Abstract
Axonal degeneration is an early hallmark of nerve injury and many neurodegenerative diseases. The discovery of the Wallerian degeneration slow mutant mouse, in which axonal degeneration is delayed, revealed that Wallerian degeneration is an active progress and thereby illuminated the mechanisms underlying axonal degeneration. Nicotinamide mononucleotide adenylyltransferase 2 and sterile alpha and armadillo motif-containing protein 1 play essential roles in the maintenance of axon integrity by regulating the level of nicotinamide adenine dinucleotide, which seems to be the key molecule involved in the maintenance of axonal health. However, the function of nicotinamide mononucleotide remains debatable, and we discuss two apparently conflicting roles of nicotinamide mononucleotide in Wallerian degeneration. In this article, we focus on the roles of these molecules in the initiation phase of Wallerian degeneration to improve our understanding of the mechanisms underpinning this phenomenon.
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Affiliation(s)
- Biao Chang
- Institute of Orthopedics, General Hospital of People's Liberation Army, 28th Fuxing Road, Beijing, China.,Beijing Key Laboratory of Regenerative Medicine in Orthopedics, Beijing, China.,Key Laboratory of Musculoskeletal Trauma & War Injuries, People's Liberation Army, Beijing, China
| | - Qi Quan
- Institute of Orthopedics, General Hospital of People's Liberation Army, 28th Fuxing Road, Beijing, China.,Beijing Key Laboratory of Regenerative Medicine in Orthopedics, Beijing, China.,Key Laboratory of Musculoskeletal Trauma & War Injuries, People's Liberation Army, Beijing, China
| | - Shibi Lu
- Institute of Orthopedics, General Hospital of People's Liberation Army, 28th Fuxing Road, Beijing, China.,Beijing Key Laboratory of Regenerative Medicine in Orthopedics, Beijing, China.,Key Laboratory of Musculoskeletal Trauma & War Injuries, People's Liberation Army, Beijing, China
| | - Yu Wang
- Institute of Orthopedics, General Hospital of People's Liberation Army, 28th Fuxing Road, Beijing, China.,Beijing Key Laboratory of Regenerative Medicine in Orthopedics, Beijing, China.,Key Laboratory of Musculoskeletal Trauma & War Injuries, People's Liberation Army, Beijing, China.,The Neural Regeneration Co-innovation Center of Jiangsu Province, Nantong, China
| | - Jiang Peng
- Institute of Orthopedics, General Hospital of People's Liberation Army, 28th Fuxing Road, Beijing, China.,Beijing Key Laboratory of Regenerative Medicine in Orthopedics, Beijing, China.,Key Laboratory of Musculoskeletal Trauma & War Injuries, People's Liberation Army, Beijing, China.,The Neural Regeneration Co-innovation Center of Jiangsu Province, Nantong, China
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121
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Axon degeneration: context defines distinct pathways. Curr Opin Neurobiol 2016; 39:108-15. [PMID: 27197022 DOI: 10.1016/j.conb.2016.05.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 05/02/2016] [Accepted: 05/03/2016] [Indexed: 12/29/2022]
Abstract
Axon degeneration is an essential part of development, plasticity, and injury response and has been primarily studied in mammalian models in three contexts: 1) Axotomy-induced Wallerian degeneration, 2) Apoptosis-induced axon degeneration (axon apoptosis), and 3) Axon pruning. These three contexts dictate engagement of distinct pathways for axon degeneration. Recent advances have identified the importance of SARM1, NMNATs, NAD+ depletion, and MAPK signaling in axotomy-induced Wallerian degeneration. Interestingly, apoptosis-induced axon degeneration and axon pruning have many shared mechanisms both in signaling (e.g. DLK, JNKs, GSK3α/β) and execution (e.g. Puma, Bax, caspase-9, caspase-3). However, the specific mechanisms by which caspases are activated during apoptosis versus pruning appear distinct, with apoptosis requiring Apaf-1 but not caspase-6 while pruning requires caspase-6 but not Apaf-1.
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122
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Henninger N, Bouley J, Sikoglu EM, An J, Moore CM, King JA, Bowser R, Freeman MR, Brown RH. Attenuated traumatic axonal injury and improved functional outcome after traumatic brain injury in mice lacking Sarm1. Brain 2016; 139:1094-105. [PMID: 26912636 PMCID: PMC5006226 DOI: 10.1093/brain/aww001] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 11/02/2015] [Accepted: 12/04/2015] [Indexed: 01/01/2023] Open
Abstract
Axonal degeneration is a critical, early event in many acute and chronic neurological disorders. It has been consistently observed after traumatic brain injury, but whether axon degeneration is a driver of traumatic brain injury remains unclear. Molecular pathways underlying the pathology of traumatic brain injury have not been defined, and there is no efficacious treatment for traumatic brain injury. Here we show that mice lacking the mouse Toll receptor adaptor Sarm1 (sterile α/Armadillo/Toll-Interleukin receptor homology domain protein) gene, a key mediator of Wallerian degeneration, demonstrate multiple improved traumatic brain injury-associated phenotypes after injury in a closed-head mild traumatic brain injury model. Sarm1(-/-) mice developed fewer β-amyloid precursor protein aggregates in axons of the corpus callosum after traumatic brain injury as compared to Sarm1(+/+) mice. Furthermore, mice lacking Sarm1 had reduced plasma concentrations of the phophorylated axonal neurofilament subunit H, indicating that axonal integrity is maintained after traumatic brain injury. Strikingly, whereas wild-type mice exibited a number of behavioural deficits after traumatic brain injury, we observed a strong, early preservation of neurological function in Sarm1(-/-) animals. Finally, using in vivo proton magnetic resonance spectroscopy we found tissue signatures consistent with substantially preserved neuronal energy metabolism in Sarm1(-/-) mice compared to controls immediately following traumatic brain injury. Our results indicate that the SARM1-mediated prodegenerative pathway promotes pathogenesis in traumatic brain injury and suggest that anti-SARM1 therapeutics are a viable approach for preserving neurological function after traumatic brain injury.
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Affiliation(s)
- Nils Henninger
- 1 Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01655, USA 2 Department of Psychiatry University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - James Bouley
- 1 Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Elif M Sikoglu
- 2 Department of Psychiatry University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Jiyan An
- 3 Divisions of Neurology and Neurobiology, Barrow Neurological Institute, Phoenix, AZ 85013, USA
| | - Constance M Moore
- 2 Department of Psychiatry University of Massachusetts Medical School, Worcester, MA 01655, USA 4 Department of Radiology University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Jean A King
- 1 Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01655, USA 2 Department of Psychiatry University of Massachusetts Medical School, Worcester, MA 01655, USA 4 Department of Radiology University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Robert Bowser
- 3 Divisions of Neurology and Neurobiology, Barrow Neurological Institute, Phoenix, AZ 85013, USA
| | - Marc R Freeman
- 5 Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Robert H Brown
- 1 Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01655, USA
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123
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Kurbatskaya K, Phillips EC, Croft CL, Dentoni G, Hughes MM, Wade MA, Al-Sarraj S, Troakes C, O’Neill MJ, Perez-Nievas BG, Hanger DP, Noble W. Upregulation of calpain activity precedes tau phosphorylation and loss of synaptic proteins in Alzheimer's disease brain. Acta Neuropathol Commun 2016; 4:34. [PMID: 27036949 PMCID: PMC4818436 DOI: 10.1186/s40478-016-0299-2] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 03/15/2016] [Indexed: 12/05/2022] Open
Abstract
Alterations in calcium homeostasis are widely reported to contribute to synaptic degeneration and neuronal loss in Alzheimer’s disease. Elevated cytosolic calcium concentrations lead to activation of the calcium-sensitive cysteine protease, calpain, which has a number of substrates known to be abnormally regulated in disease. Analysis of human brain has shown that calpain activity is elevated in AD compared to controls, and that calpain-mediated proteolysis regulates the activity of important disease-associated proteins including the tau kinases cyclin-dependent kinase 5 and glycogen kinase synthase-3. Here, we sought to investigate the likely temporal association between these changes during the development of sporadic AD using Braak staged post-mortem brain. Quantification of protein amounts in these tissues showed increased activity of calpain-1 from Braak stage III onwards in comparison to controls, extending previous findings that calpain-1 is upregulated at end-stage disease, and suggesting that activation of calcium-sensitive signalling pathways are sustained from early stages of disease development. Increases in calpain-1 activity were associated with elevated activity of the endogenous calpain inhibitor, calpastatin, itself a known calpain substrate. Activation of the tau kinases, glycogen-kinase synthase-3 and cyclin-dependent kinase 5 were also found to occur in Braak stage II-III brain, and these preceded global elevations in tau phosphorylation and the loss of post-synaptic markers. In addition, we identified transient increases in total amyloid precursor protein and pre-synaptic markers in Braak stage II-III brain, that were lost by end stage Alzheimer's disease, that may be indicative of endogenous compensatory responses to the initial stages of neurodegeneration. These findings provide insight into the molecular events that underpin the progression of Alzheimer's disease, and further highlight the rationale for investigating novel treatment strategies that are based on preventing abnormal calcium homeostasis or blocking increases in the activity of calpain or important calpain substrates.
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124
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Traumatic Axonal Injury: Mechanisms and Translational Opportunities. Trends Neurosci 2016; 39:311-324. [PMID: 27040729 PMCID: PMC5405046 DOI: 10.1016/j.tins.2016.03.002] [Citation(s) in RCA: 188] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 03/06/2016] [Accepted: 03/07/2016] [Indexed: 12/22/2022]
Abstract
Traumatic axonal injury (TAI) is an important pathoanatomical subgroup of traumatic brain injury (TBI) and a major driver of mortality and functional impairment. Experimental models have provided insights into the effects of mechanical deformation on the neuronal cytoskeleton and the subsequent processes that drive axonal injury. There is also increasing recognition that axonal or white matter loss may progress for years post-injury and represent one mechanistic framework for progressive neurodegeneration after TBI. Previous trials of novel therapies have failed to make an impact on clinical outcome, in both TBI in general and TAI in particular. Recent advances in understanding the cellular and molecular mechanisms of injury have the potential to translate into novel therapeutic targets. Multiple therapeutic targets are emerging that offer the potential to reduce secondary brain injury at a cellular level. These include cytoskeletal and membrane stabilisation, control of calcium flux and calpain activation, optimisation of cellular energetics, and modulation of the inflammatory response. Wallerian degeneration, as occurs following an axonal injury, is an active, cell-autonomous death pathway that involves failure of axonal transport to deliver key enzymes involved in NAD biosynthesis. Chronic microglial activation occurs following traumatic brain injury (TBI) and may persist for decades afterwards. This ongoing response has been linked to long-term neurodegeneration, particularly of white matter tracts. Phagoptosis is the process whereby physiologically stressed but otherwise viable neurons are phagocytosed by microglia in response to a range of eat-me signals induced by tissue injury.
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125
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de Lima S, Mietto BS, Paula C, Muniz T, Martinez AMB, Gardino PF. Rescuing axons from degeneration does not affect retinal ganglion cell death. Braz J Med Biol Res 2016; 49:e5106. [PMID: 27007653 PMCID: PMC4819409 DOI: 10.1590/1414-431x20155106] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 10/28/2015] [Indexed: 11/22/2022] Open
Abstract
After a traumatic injury to the central nervous system, the distal stumps of axons undergo Wallerian degeneration (WD), an event that comprises cytoskeleton and myelin breakdown, astrocytic gliosis, and overexpression of proteins that inhibit axonal regrowth. By contrast, injured neuronal cell bodies show features characteristic of attempts to initiate the regenerative process of elongating their axons. The main molecular event that leads to WD is an increase in the intracellular calcium concentration, which activates calpains, calcium-dependent proteases that degrade cytoskeleton proteins. The aim of our study was to investigate whether preventing axonal degeneration would impact the survival of retinal ganglion cells (RGCs) after crushing the optic nerve. We observed that male Wistar rats (weighing 200-400 g; n=18) treated with an exogenous calpain inhibitor (20 mM) administered via direct application of the inhibitor embedded within the copolymer resin Evlax immediately following optic nerve crush showed a delay in the onset of WD. This delayed onset was characterized by a decrease in the number of degenerated fibers (P<0.05) and an increase in the number of preserved fibers (P<0.05) 4 days after injury. Additionally, most preserved fibers showed a normal G-ratio. These results indicated that calpain inhibition prevented the degeneration of optic nerve fibers, rescuing axons from the process of axonal degeneration. However, analysis of retinal ganglion cell survival demonstrated no difference between the calpain inhibitor- and vehicle-treated groups, suggesting that although the calpain inhibitor prevented axonal degeneration, it had no effect on RGC survival after optic nerve damage.
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Affiliation(s)
- S de Lima
- Laboratório de Neurobiologia da Retina, Centro de Ciências da Saúde, Instituto de Biofísica Carlos Chagas Filho, Rio de Janeiro, RJ, Brasil
| | - B S Mietto
- Laboratório de Neurodegeneração e Reparo, Departamento de Patologia, Faculdade de Medicina, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brasil
| | - C Paula
- Laboratório de Neurobiologia da Retina, Centro de Ciências da Saúde, Instituto de Biofísica Carlos Chagas Filho, Rio de Janeiro, RJ, Brasil
| | - T Muniz
- Laboratório de Neurobiologia da Retina, Centro de Ciências da Saúde, Instituto de Biofísica Carlos Chagas Filho, Rio de Janeiro, RJ, Brasil
| | - A M B Martinez
- Laboratório de Neurodegeneração e Reparo, Departamento de Patologia, Faculdade de Medicina, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brasil
| | - P F Gardino
- Laboratório de Neurobiologia da Retina, Centro de Ciências da Saúde, Instituto de Biofísica Carlos Chagas Filho, Rio de Janeiro, RJ, Brasil
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Simon DJ, Pitts J, Hertz NT, Yang J, Yamagishi Y, Olsen O, Tešić Mark M, Molina H, Tessier-Lavigne M. Axon Degeneration Gated by Retrograde Activation of Somatic Pro-apoptotic Signaling. Cell 2016; 164:1031-45. [PMID: 26898330 DOI: 10.1016/j.cell.2016.01.032] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 11/22/2015] [Accepted: 01/20/2016] [Indexed: 11/16/2022]
Abstract
During development, sensory axons compete for limiting neurotrophic support, and local neurotrophin insufficiency triggers caspase-dependent axon degeneration. The signaling driving axon degeneration upon local deprivation is proposed to reside within axons. Our results instead support a model in which, despite the apoptotic machinery being present in axons, the cell body is an active participant in gating axonal caspase activation and axon degeneration. Loss of trophic support in axons initiates retrograde activation of a somatic pro-apoptotic pathway, which, in turn, is required for distal axon degeneration via an anterograde pro-degenerative factor. At a molecular level, the cell body is the convergence point of two signaling pathways whose integrated action drives upregulation of pro-apoptotic Puma, which, unexpectedly, is confined to the cell body. Puma then overcomes inhibition by pro-survival Bcl-xL and Bcl-w and initiates the anterograde pro-degenerative program, highlighting the role of the cell body as an arbiter of large-scale axon removal.
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Affiliation(s)
- David J Simon
- Laboratory of Brain Development and Repair, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Jason Pitts
- Laboratory of Brain Development and Repair, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Nicholas T Hertz
- Laboratory of Brain Development and Repair, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Jing Yang
- Laboratory of Brain Development and Repair, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Yuya Yamagishi
- Laboratory of Brain Development and Repair, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Olav Olsen
- Laboratory of Brain Development and Repair, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Milica Tešić Mark
- Proteomics Resource Center, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Henrik Molina
- Proteomics Resource Center, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | - Marc Tessier-Lavigne
- Laboratory of Brain Development and Repair, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
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127
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Gerdts J, Summers DW, Milbrandt J, DiAntonio A. Axon Self-Destruction: New Links among SARM1, MAPKs, and NAD+ Metabolism. Neuron 2016; 89:449-60. [PMID: 26844829 PMCID: PMC4742785 DOI: 10.1016/j.neuron.2015.12.023] [Citation(s) in RCA: 245] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Wallerian axon degeneration is a form of programmed subcellular death that promotes axon breakdown in disease and injury. Active degeneration requires SARM1 and MAP kinases, including DLK, while the NAD+ synthetic enzyme NMNAT2 prevents degeneration. New studies reveal that these pathways cooperate in a locally mediated axon destruction program, with NAD+ metabolism playing a central role. Here, we review the biology of Wallerian-type axon degeneration and discuss the most recent findings, with special emphasis on critical signaling events and their potential as therapeutic targets for axonopathy.
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Affiliation(s)
- Josiah Gerdts
- Department of Genetics, Washington University School of Medicine in St. Louis, 660 Euclid Avenue, St. Louis, MO 63110, USA
| | - Daniel W Summers
- Department of Genetics, Washington University School of Medicine in St. Louis, 660 Euclid Avenue, St. Louis, MO 63110, USA; Department of Developmental Biology, Washington University School of Medicine in St. Louis, 660 Euclid Avenue, St. Louis, MO 63110, USA
| | - Jeffrey Milbrandt
- Department of Genetics, Washington University School of Medicine in St. Louis, 660 Euclid Avenue, St. Louis, MO 63110, USA; Hope Center for Neurological Disorders, 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; Hope Center for Neurological Disorders, Washington University School of Medicine in St. Louis, 660 Euclid Avenue, St. Louis, MO 63110, USA.
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128
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Wallerian Degeneration Is Executed by an NMN-SARM1-Dependent Late Ca(2+) Influx but Only Modestly Influenced by Mitochondria. Cell Rep 2015; 13:2539-2552. [PMID: 26686637 DOI: 10.1016/j.celrep.2015.11.032] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 09/01/2015] [Accepted: 11/06/2015] [Indexed: 11/23/2022] Open
Abstract
Axon injury leads to rapid depletion of NAD-biosynthetic enzyme NMNAT2 and high levels of its substrate, NMN. We proposed a key role for NMN in Wallerian degeneration but downstream events and their relationship to other mediators remain unclear. Here, we show, in vitro and in vivo, that axotomy leads to a late increase in intra-axonal Ca(2+), abolished by pharmacological or genetic reduction of NMN levels. NMN requires the pro-degenerative protein SARM1 to stimulate Ca(2+) influx and axon degeneration. While inhibition of NMN synthesis and SARM1 deletion block Ca(2+) rise and preserve axonal integrity, they fail to prevent early mitochondrial dynamic changes. Furthermore, depolarizing mitochondria does not alter the rate of Wallerian degeneration. These data reveal that NMN and SARM1 act in a common pathway culminating in intra-axonal Ca(2+) increase and fragmentation and dissociate mitochondrial dysfunctions from this pathway, elucidating which steps may be most effective as targets for therapy.
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129
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Vargas ME, Yamagishi Y, Tessier-Lavigne M, Sagasti A. Live Imaging of Calcium Dynamics during Axon Degeneration Reveals Two Functionally Distinct Phases of Calcium Influx. J Neurosci 2015; 35:15026-38. [PMID: 26558774 PMCID: PMC4642236 DOI: 10.1523/jneurosci.2484-15.2015] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 09/30/2015] [Accepted: 10/07/2015] [Indexed: 12/29/2022] Open
Abstract
Calcium is a key regulator of axon degeneration caused by trauma and disease, but its specific spatial and temporal dynamics in injured axons remain unclear. To clarify the function of calcium in axon degeneration, we observed calcium dynamics in single injured neurons in live zebrafish larvae and tested the temporal requirement for calcium in zebrafish neurons and cultured mouse DRG neurons. Using laser axotomy to induce Wallerian degeneration (WD) in zebrafish peripheral sensory axons, we monitored calcium dynamics from injury to fragmentation, revealing two stereotyped phases of axonal calcium influx. First, axotomy triggered a transient local calcium wave originating at the injury site. This initial calcium wave only disrupted mitochondria near the injury site and was not altered by expression of the protective WD slow (WldS) protein. Inducing multiple waves with additional axotomies did not change the kinetics of degeneration. In contrast, a second phase of calcium influx occurring minutes before fragmentation spread as a wave throughout the axon, entered mitochondria, and was abolished by WldS expression. In live zebrafish, chelating calcium after the first wave, but before the second wave, delayed the progress of fragmentation. In cultured DRG neurons, chelating calcium early in the process of WD did not alter degeneration, but chelating calcium late in WD delayed fragmentation. We propose that a terminal calcium wave is a key instructive component of the axon degeneration program. SIGNIFICANCE STATEMENT Axon degeneration resulting from trauma or neurodegenerative disease can cause devastating deficits in neural function. Understanding the molecular and cellular events that execute axon degeneration is essential for developing treatments to address these conditions. Calcium is known to contribute to axon degeneration, but its temporal requirements in this process have been unclear. Live calcium imaging in severed zebrafish neurons and temporally controlled pharmacological treatments in both zebrafish and cultured mouse sensory neurons revealed that axonal calcium influx late in the degeneration process regulates axon fragmentation. These findings suggest that temporal considerations will be crucial for developing treatments for diseases associated with axon degeneration.
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Affiliation(s)
- Mauricio Enrique Vargas
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095, Jules Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California 90095, and
| | - Yuya Yamagishi
- Laboratory of Brain Development and Repair, The Rockefeller University, New York, New York 10065
| | - Marc Tessier-Lavigne
- Laboratory of Brain Development and Repair, The Rockefeller University, New York, New York 10065
| | - Alvaro Sagasti
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095,
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130
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Jantzie LL, Winer JL, Corbett CJ, Robinson S. Erythropoietin Modulates Cerebral and Serum Degradation Products from Excess Calpain Activation following Prenatal Hypoxia-Ischemia. Dev Neurosci 2015; 38:15-26. [PMID: 26551007 DOI: 10.1159/000441024] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 09/10/2015] [Indexed: 01/20/2023] Open
Abstract
Preterm infants suffer central nervous system (CNS) injury from hypoxia-ischemia and inflammation - termed encephalopathy of prematurity. Mature CNS injury activates caspase and calpain proteases. Erythropoietin (EPO) limits apoptosis mediated by activated caspases, but its role in modulating calpain activation has not yet been investigated extensively following injury to the developing CNS. We hypothesized that excess calpain activation degrades developmentally regulated molecules essential for CNS circuit formation, myelination and axon integrity, including neuronal potassium-chloride co-transporter (KCC2), myelin basic protein (MBP) and phosphorylated neurofilament (pNF), respectively. Further, we predicted that post-injury EPO treatment could mitigate CNS calpain-mediated degradation. Using prenatal transient systemic hypoxia-ischemia (TSHI) in rats to mimic CNS injury from extreme preterm birth, and postnatal EPO treatment with a clinically relevant dosing regimen, we found sustained postnatal excess cortical calpain activation following prenatal TSHI, as shown by the cleavage of alpha II-spectrin (αII-spectrin) into 145-kDa αII-spectrin degradation products (αII-SDPs) and p35 into p25. Postnatal expression of the endogenous calpain inhibitor calpastatin was also reduced following prenatal TSHI. Calpain substrate expression following TSHI, including cortical KCC2, MBP and NF, was modulated by postnatal EPO treatment. Calpain activation was reflected in serum levels of αII-SDPs and KCC2 fragments, and notably, EPO treatment also modulated KCC2 fragment levels. Together, these data indicate that excess calpain activity contributes to the pathogenesis of encephalopathy of prematurity. Serum biomarkers of calpain activation may detect ongoing cerebral injury and responsiveness to EPO or similar neuroprotective strategies.
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Affiliation(s)
- Lauren L Jantzie
- Department of Neurosurgery, Boston Children's Hospital and Harvard Medical School, Boston, Mass., USA
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131
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The Role of Proteases in Hippocampal Synaptic Plasticity: Putting Together Small Pieces of a Complex Puzzle. Neurochem Res 2015; 41:156-82. [DOI: 10.1007/s11064-015-1752-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 10/26/2015] [Accepted: 10/27/2015] [Indexed: 12/17/2022]
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132
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Furukawa A, Koriyama Y. A role of Heat Shock Protein 70 in Photoreceptor Cell Death: Potential as a Novel Therapeutic Target in Retinal Degeneration. CNS Neurosci Ther 2015; 22:7-14. [PMID: 26507240 DOI: 10.1111/cns.12471] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 09/23/2015] [Accepted: 09/25/2015] [Indexed: 01/17/2023] Open
Abstract
Retinal degenerative diseases (RDs) such as retinitis pigmentosa (RP) are a genetically heterogeneous group of disorders characterized by night blindness and peripheral vision loss, which caused by the dysfunction and death of photoreceptor cells. Although many causative gene mutations have been reported, the final common end stage is photoreceptor cell death. Unfortunately, no effective treatments or therapeutic agents have been discovered. Heat shock protein 70 (HSP70) is highly conserved and has antiapoptotic activities. A few reports have shown that HSP70 plays a role in RDs. Thus, we focused on the role of HSP70 in photoreceptor cell death. Using the N-methyl-N-nitrosourea (MNU)-induced photoreceptor cell death model in mice, we could examine two stages of the novel cell death mechanism; the early stage, including HSP70 cleavage through protein carbonylation by production of reactive oxygen species, lipid peroxidation and Ca(2+) influx/calpain activation, and the late stage of cathepsin and/or caspase activation. The upregulation of intact HSP70 expression by its inducer is likely to protect photoreceptor cells. In this review, we focus on the role of HSP70 and the novel cell death signaling process in RDs. We also describe candidate therapeutic agents for RDs.
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Affiliation(s)
- Ayako Furukawa
- Graduate School and Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan
| | - Yoshiki Koriyama
- Graduate School and Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan
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133
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Clemens LE, Weber JJ, Wlodkowski TT, Yu-Taeger L, Michaud M, Calaminus C, Eckert SH, Gaca J, Weiss A, Magg JCD, Jansson EKH, Eckert GP, Pichler BJ, Bordet T, Pruss RM, Riess O, Nguyen HP. Olesoxime suppresses calpain activation and mutant huntingtin fragmentation in the BACHD rat. Brain 2015; 138:3632-53. [PMID: 26490331 DOI: 10.1093/brain/awv290] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 08/11/2015] [Indexed: 12/14/2022] Open
Abstract
Huntington's disease is a fatal human neurodegenerative disorder caused by a CAG repeat expansion in the HTT gene, which translates into a mutant huntingtin protein. A key event in the molecular pathogenesis of Huntington's disease is the proteolytic cleavage of mutant huntingtin, leading to the accumulation of toxic protein fragments. Mutant huntingtin cleavage has been linked to the overactivation of proteases due to mitochondrial dysfunction and calcium derangements. Here, we investigated the therapeutic potential of olesoxime, a mitochondria-targeting, neuroprotective compound, in the BACHD rat model of Huntington's disease. BACHD rats were treated with olesoxime via the food for 12 months. In vivo analysis covered motor impairments, cognitive deficits, mood disturbances and brain atrophy. Ex vivo analyses addressed olesoxime's effect on mutant huntingtin aggregation and cleavage, as well as brain mitochondria function. Olesoxime improved cognitive and psychiatric phenotypes, and ameliorated cortical thinning in the BACHD rat. The treatment reduced cerebral mutant huntingtin aggregates and nuclear accumulation. Further analysis revealed a cortex-specific overactivation of calpain in untreated BACHD rats. Treated BACHD rats instead showed significantly reduced levels of mutant huntingtin fragments due to the suppression of calpain-mediated cleavage. In addition, olesoxime reduced the amount of mutant huntingtin fragments associated with mitochondria, restored a respiration deficit, and enhanced the expression of fusion and outer-membrane transport proteins. In conclusion, we discovered the calpain proteolytic system, a key player in Huntington's disease and other neurodegenerative disorders, as a target of olesoxime. Our findings suggest that olesoxime exerts its beneficial effects by improving mitochondrial function, which results in reduced calpain activation. The observed alleviation of behavioural and neuropathological phenotypes encourages further investigations on the use of olesoxime as a therapeutic for Huntington's disease.
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Affiliation(s)
- Laura E Clemens
- 1 Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstrasse 7, 72076 Tuebingen, Germany 2 Centre for Rare Diseases, University of Tuebingen, Calwerstrasse 7, 72076 Tuebingen, Germany
| | - Jonasz J Weber
- 1 Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstrasse 7, 72076 Tuebingen, Germany 2 Centre for Rare Diseases, University of Tuebingen, Calwerstrasse 7, 72076 Tuebingen, Germany
| | - Tanja T Wlodkowski
- 1 Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstrasse 7, 72076 Tuebingen, Germany 2 Centre for Rare Diseases, University of Tuebingen, Calwerstrasse 7, 72076 Tuebingen, Germany
| | - Libo Yu-Taeger
- 1 Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstrasse 7, 72076 Tuebingen, Germany 2 Centre for Rare Diseases, University of Tuebingen, Calwerstrasse 7, 72076 Tuebingen, Germany
| | - Magali Michaud
- 3 Trophos SA., Parc Scientifique de Luminy Case 931, 13288 Marseille Cedex 9, France
| | - Carsten Calaminus
- 4 Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, University of Tuebingen, Roentgenweg 13, 72076 Tuebingen, Germany
| | - Schamim H Eckert
- 5 Department of Pharmacology, Goethe University Frankfurt am Main, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Janett Gaca
- 5 Department of Pharmacology, Goethe University Frankfurt am Main, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Andreas Weiss
- 6 Novartis Institutes for BioMedical Research, Klybeckstrasse 141, 4057 Basel, Switzerland
| | - Janine C D Magg
- 1 Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstrasse 7, 72076 Tuebingen, Germany 2 Centre for Rare Diseases, University of Tuebingen, Calwerstrasse 7, 72076 Tuebingen, Germany
| | - Erik K H Jansson
- 1 Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstrasse 7, 72076 Tuebingen, Germany 2 Centre for Rare Diseases, University of Tuebingen, Calwerstrasse 7, 72076 Tuebingen, Germany
| | - Gunter P Eckert
- 5 Department of Pharmacology, Goethe University Frankfurt am Main, Max-von-Laue Str. 9, 60438 Frankfurt, Germany
| | - Bernd J Pichler
- 4 Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, University of Tuebingen, Roentgenweg 13, 72076 Tuebingen, Germany
| | - Thierry Bordet
- 3 Trophos SA., Parc Scientifique de Luminy Case 931, 13288 Marseille Cedex 9, France
| | - Rebecca M Pruss
- 3 Trophos SA., Parc Scientifique de Luminy Case 931, 13288 Marseille Cedex 9, France
| | - Olaf Riess
- 1 Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstrasse 7, 72076 Tuebingen, Germany 2 Centre for Rare Diseases, University of Tuebingen, Calwerstrasse 7, 72076 Tuebingen, Germany
| | - Huu P Nguyen
- 1 Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Calwerstrasse 7, 72076 Tuebingen, Germany 2 Centre for Rare Diseases, University of Tuebingen, Calwerstrasse 7, 72076 Tuebingen, Germany
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134
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Abstract
The assembly of functional neural circuits requires the combined action of progressive and regressive events. Regressive events encompass a variety of inhibitory developmental processes, including axon and dendrite pruning, which facilitate the removal of exuberant neuronal connections. Most axon pruning involves the removal of axons that had already made synaptic connections; thus, axon pruning is tightly associated with synapse elimination. In many instances, these developmental processes are regulated by the interplay between neurons and glial cells that act instructively during neural remodeling. Owing to the importance of axon and dendritic pruning, these remodeling events require precise spatial and temporal control, and this is achieved by a range of distinct molecular mechanisms. Disruption of these mechanisms results in abnormal pruning, which has been linked to brain dysfunction. Therefore, understanding the mechanisms of axon and dendritic pruning will be instrumental in advancing our knowledge of neural disease and mental disorders.
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Affiliation(s)
- Martin M Riccomagno
- Department of Cell Biology and Neuroscience, University of California, Riverside, California 92521;
| | - Alex L Kolodkin
- Solomon H. Snyder Department of Neuroscience, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205;
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135
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Zhang L, Ou J, Xu X, Peng Y, Guo H, Pan Y, Chen J, Wang T, Peng H, Liu Q, Tian D, Pan Q, Zou X, Zhao J, Hu Z, Xia K. AMPD1 functional variants associated with autism in Han Chinese population. Eur Arch Psychiatry Clin Neurosci 2015; 265:511-7. [PMID: 25155876 DOI: 10.1007/s00406-014-0524-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 08/09/2014] [Indexed: 11/25/2022]
Abstract
Autism is a childhood neurodevelopmental disorder with high heterogeneity. Following our genome-wide associated loci with autism, we performed sequencing analysis of the coding regions, UTR and flanking splice junctions of AMPD1 in 830 Chinese autism individuals as well as 514 unrelated normal controls. Fourteen novel variants in the coding sequence were identified, including 11 missense variants and 3 synonymous mutations. Among these missense variants, 10 variants were absent in 514 control subjects, and conservative and functional prediction was carried out. Mitochondria activity and lactate dehydrogenase assay were performed in 5 patients' lymphoblast cell lines; p.P572S and p.S626C showed decreased mitochondrial complex I activity, and p.S626C increased lactate dehydrogenase release in medium. Conclusively, our data suggested that mutational variants in AMPD1 contribute to autism risk in Han Chinese population, uncovering the contribution of mutant protein to disease development that operates via mitochondria dysfunction and cell necrosis.
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Affiliation(s)
- Lusi Zhang
- State Key Laboratory of Medical Genetics, Central South University, 110, Xiangya Road, Changsha, Hunan, China
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136
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Cashman CR, Höke A. Mechanisms of distal axonal degeneration in peripheral neuropathies. Neurosci Lett 2015; 596:33-50. [PMID: 25617478 PMCID: PMC4428955 DOI: 10.1016/j.neulet.2015.01.048] [Citation(s) in RCA: 145] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 01/16/2015] [Accepted: 01/19/2015] [Indexed: 02/08/2023]
Abstract
Peripheral neuropathy is a common complication of a variety of diseases and treatments, including diabetes, cancer chemotherapy, and infectious causes (HIV, hepatitis C, and Campylobacter jejuni). Despite the fundamental difference between these insults, peripheral neuropathy develops as a combination of just six primary mechanisms: altered metabolism, covalent modification, altered organelle function and reactive oxygen species formation, altered intracellular and inflammatory signaling, slowed axonal transport, and altered ion channel dynamics and expression. All of these pathways converge to lead to axon dysfunction and symptoms of neuropathy. The detailed mechanisms of axon degeneration itself have begun to be elucidated with studies of animal models with altered degeneration kinetics, including the slowed Wallerian degeneration (Wld(S)) and Sarm knockout animal models. These studies have shown axonal degeneration to occur through a programmed pathway of injury signaling and cytoskeletal degradation. Insights into the common disease insults that converge on the axonal degeneration pathway promise to facilitate the development of therapeutics that may be effective against other mechanisms of neurodegeneration.
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Affiliation(s)
- Christopher R Cashman
- Departments of Neuroscience and Neurology, USA; MSTP- MD/PhD Program, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Ahmet Höke
- Departments of Neuroscience and Neurology, USA.
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137
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Song S, Mitchell DE, Crowder NA, Duffy KR. Postnatal accumulation of intermediate filaments in the cat and human primary visual cortex. J Comp Neurol 2015; 523:2111-26. [PMID: 25823892 DOI: 10.1002/cne.23781] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 03/16/2015] [Accepted: 03/17/2015] [Indexed: 12/25/2022]
Abstract
A principal characteristic of the mammalian visual system is its high capacity for plasticity in early postnatal development during a time commonly referred to as the critical period. The progressive diminution of plasticity with age is linked to the emergence of a collection of molecules called molecular brakes that reduce plasticity and stabilize neural circuits modified by earlier visual experiences. Manipulation of braking molecules either pharmacologically or though experiential alteration enhances plasticity and promotes recovery from visual impairment. The stability of neural circuitry is increased by intermediate filamentous proteins of the cytoskeleton such as neurofilaments and α-internexin. We examined levels of these intermediate filaments within cat and human primary visual cortex (V1) across development to determine whether they accumulate following a time course consistent with a molecular brake. In both species, levels of intermediate filaments increased considerably throughout early postnatal life beginning shortly after the peak of the critical period, with the highest levels measured in adults. Neurofilament phosphorylation was also observed to increase throughout development, raising the possibility that posttranslational modification by phosphorylation reduces plasticity due to increased protein stability. Finally, an approach to scale developmental time points between species is presented that compares the developmental profiles of intermediate filaments between cats and humans. Although causality between intermediate filaments and plasticity was not directly tested in this study, their accumulation relative to the critical period indicates that they may contribute to the decline in plasticity with age, and may also constrain the success of treatments for visual disorders applied in adulthood.
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Affiliation(s)
- Seoho Song
- Department of Psychology and Neuroscience, Dalhousie University, Life Sciences Centre, Halifax, Nova Scotia, Canada, B3H 4R2
| | - Donald E Mitchell
- Department of Psychology and Neuroscience, Dalhousie University, Life Sciences Centre, Halifax, Nova Scotia, Canada, B3H 4R2
| | - Nathan A Crowder
- Department of Psychology and Neuroscience, Dalhousie University, Life Sciences Centre, Halifax, Nova Scotia, Canada, B3H 4R2
| | - Kevin R Duffy
- Department of Psychology and Neuroscience, Dalhousie University, Life Sciences Centre, Halifax, Nova Scotia, Canada, B3H 4R2
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138
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Identification of 12/15-lipoxygenase as a regulator of axon degeneration through high-content screening. J Neurosci 2015; 35:2927-41. [PMID: 25698732 DOI: 10.1523/jneurosci.2936-14.2015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Axon degeneration is a programed process that takes place during development, in response to neuronal injury, and as a component of neurodegenerative disease pathology, yet the molecular mechanisms that drive this process remain poorly defined. In this study, we have developed a semi-automated, 384-well format axon degeneration assay in rat dorsal root ganglion (DRG) neurons using a trophic factor withdrawal paradigm. Using this setup, we have screened a library of known drugs and bioactives to identify several previously unappreciated regulators of axon degeneration, including lipoxygenases. Multiple structurally distinct lipoxygenase inhibitors as well as mouse DRG neurons lacking expression of 12/15-lipoxygenase display protection of axons in this context. Retinal ganglion cell axons from 12/15-lipoxygenase-null mice were similarly protected from degeneration following nerve crush injury. Through additional mechanistic studies, we demonstrate that lipoxygenases act cell autonomously within neurons to regulate degeneration, and are required for mitochondrial permeabilization and caspase activation in the axon. These findings suggest that these enzymes may represent an attractive target for treatment of neuropathies and provide a potential mechanism for the neuroprotection observed in various settings following lipoxygenase inhibitor treatment.
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139
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Yang J, Wu Z, Renier N, Simon DJ, Uryu K, Park DS, Greer PA, Tournier C, Davis RJ, Tessier-Lavigne M. Pathological axonal death through a MAPK cascade that triggers a local energy deficit. Cell 2015; 160:161-76. [PMID: 25594179 DOI: 10.1016/j.cell.2014.11.053] [Citation(s) in RCA: 223] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 09/12/2014] [Accepted: 11/20/2014] [Indexed: 11/30/2022]
Abstract
Axonal death disrupts functional connectivity of neural circuits and is a critical feature of many neurodegenerative disorders. Pathological axon degeneration often occurs independently of known programmed death pathways, but the underlying molecular mechanisms remain largely unknown. Using traumatic injury as a model, we systematically investigate mitogen-activated protein kinase (MAPK) families and delineate a MAPK cascade that represents the early degenerative response to axonal injury. The adaptor protein Sarm1 is required for activation of this MAPK cascade, and this Sarm1-MAPK pathway disrupts axonal energy homeostasis, leading to ATP depletion before physical breakdown of damaged axons. The protective cytoNmnat1/Wld(s) protein inhibits activation of this MAPK cascade. Further, MKK4, a key component in the Sarm1-MAPK pathway, is antagonized by AKT signaling, which modulates the degenerative response by limiting activation of downstream JNK signaling. Our results reveal a regulatory mechanism that integrates distinct signals to instruct pathological axon degeneration.
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Affiliation(s)
- Jing Yang
- Laboratory of Brain Development and Repair, The Rockefeller University, New York, NY 10065, USA
| | - Zhuhao Wu
- Laboratory of Brain Development and Repair, The Rockefeller University, New York, NY 10065, USA
| | - Nicolas Renier
- Laboratory of Brain Development and Repair, The Rockefeller University, New York, NY 10065, USA
| | - David J Simon
- Laboratory of Brain Development and Repair, The Rockefeller University, New York, NY 10065, USA
| | - Kunihiro Uryu
- Electron Microscopy Resource Center, The Rockefeller University, New York, NY 10065, USA
| | - David S Park
- University of Ottawa Brain and Mind Research Institute, University of Ottawa, Canada
| | - Peter A Greer
- Queen's University Cancer Research Institute, Kingston, Ontario, Canada
| | - Cathy Tournier
- University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | - Roger J Davis
- Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Marc Tessier-Lavigne
- Laboratory of Brain Development and Repair, The Rockefeller University, New York, NY 10065, USA.
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140
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Gilley J, Orsomando G, Nascimento-Ferreira I, Coleman MP. Absence of SARM1 rescues development and survival of NMNAT2-deficient axons. Cell Rep 2015; 10:1974-81. [PMID: 25818290 PMCID: PMC4386025 DOI: 10.1016/j.celrep.2015.02.060] [Citation(s) in RCA: 138] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 12/23/2014] [Accepted: 02/24/2015] [Indexed: 11/01/2022] Open
Abstract
SARM1 function and nicotinamide mononucleotide adenylyltransferase 2 (NMNAT2) loss both promote axon degeneration, but their relative relationship in the process is unknown. Here, we show that NMNAT2 loss and resultant changes to NMNAT metabolites occur in injured SARM1-deficient axons despite their delayed degeneration and that axon degeneration specifically induced by NMNAT2 depletion requires SARM1. Strikingly, SARM1 deficiency also corrects axon outgrowth in mice lacking NMNAT2, independently of NMNAT metabolites, preventing perinatal lethality. Furthermore, NAMPT inhibition partially restores outgrowth of NMNAT2-deficient axons, suggesting that the NMNAT substrate, NMN, contributes to this phenotype. NMNAT2-depletion-dependent degeneration of established axons and restricted extension of developing axons are thus both SARM1 dependent, and SARM1 acts either downstream of NMNAT2 loss and NMN accumulation in a linear pathway or in a parallel branch of a convergent pathway. Understanding the pathway will help establish relationships with other modulators of axon survival and facilitate the development of effective therapies for axonopathies.
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Affiliation(s)
- Jonathan Gilley
- Signalling Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Giuseppe Orsomando
- Department of Clinical Sciences (DISCO), Section of Biochemistry, Polytechnic University of Marche, Via Ranieri 67, Ancona 60131, Italy
| | | | - Michael P Coleman
- Signalling Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK.
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141
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Kanamori T, Yoshino J, Yasunaga KI, Dairyo Y, Emoto K. Local endocytosis triggers dendritic thinning and pruning in Drosophila sensory neurons. Nat Commun 2015; 6:6515. [DOI: 10.1038/ncomms7515] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 02/04/2015] [Indexed: 12/15/2022] Open
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142
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Armstrong RC, Mierzwa AJ, Marion CM, Sullivan GM. White matter involvement after TBI: Clues to axon and myelin repair capacity. Exp Neurol 2015; 275 Pt 3:328-333. [PMID: 25697845 DOI: 10.1016/j.expneurol.2015.02.011] [Citation(s) in RCA: 158] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 01/15/2015] [Accepted: 02/06/2015] [Indexed: 11/17/2022]
Abstract
Impact-acceleration forces to the head cause traumatic brain injury (TBI) with damage in white matter tracts comprised of long axons traversing the brain. White matter injury after TBI involves both traumatic axonal injury (TAI) and myelin pathology that evolves throughout the post-injury time course. The axon response to initial mechanical forces and secondary insults follows the process of Wallerian degeneration, which initiates as a potentially reversible phase of intra-axonal damage and proceeds to an irreversible phase of axon fragmentation. Distal to sites of axon disconnection, myelin sheaths remain for prolonged periods, which may activate neuroinflammation and inhibit axon regeneration. In addition to TAI, TBI can cause demyelination of intact axons. These evolving features of axon and myelin pathology also represent opportunities for repair. In experimental TBI, demyelinated axons exhibit remyelination, which can serve to both protect axons and facilitate recovery of function. Myelin remodeling may also contribute to neuroplasticity. Efficient clearance of myelin debris is a potential target to attenuate the progression of chronic pathology. During the early phase of Wallerian degeneration, interventions that prevent the transition from reversible damage to axon disconnection warrant the highest priority, based on the poor regenerative capacity of axons in the CNS. Clinical evaluation of TBI will need to address the challenge of accurately detecting the extent and stage of axon damage. Distinguishing the complex white matter changes associated with axons and myelin is necessary for interpreting advanced neuroimaging approaches and for identifying a broader range of therapeutic opportunities to improve outcome after TBI.
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Affiliation(s)
- Regina C Armstrong
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Program in Neuroscience, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
| | - Amanda J Mierzwa
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - Christina M Marion
- Program in Neuroscience, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
| | - Genevieve M Sullivan
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA; Center for Neuroscience and Regenerative Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA
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143
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Zang Y, Chen SX, Liao GJ, Zhu HQ, Wei XH, Cui Y, Na XD, Pang RP, Xin WJ, Zhou LJ, Liu XG. Calpain-2 contributes to neuropathic pain following motor nerve injury via up-regulating interleukin-6 in DRG neurons. Brain Behav Immun 2015; 44:37-47. [PMID: 25150005 DOI: 10.1016/j.bbi.2014.08.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 07/25/2014] [Accepted: 08/12/2014] [Indexed: 01/09/2023] Open
Abstract
Motor nerve injury by L5 ventral root transection (L5-VRT) initiates interleukin-6 (IL-6) up-regulation in primary afferent system contributing to neuropathic pain. However, the early upstream regulatory mechanisms of IL-6 after L5-VRT are still unknown. Here, we monitored both the activity of calpain, a calcium-dependent protease suggested as one of the earliest mediators for cytokine regulation, and the expression of IL-6 in bilateral L4-L6 dorsal root ganglias (DRGs) soon after L5-VRT. We found that the protein level of calpain-2 in DRGs, but not calpain-1 was increased transiently in the first 10 min(-1)h ipsilaterally and 20 min(-1)h contralaterally after L5-VRT, long before mechanical allodynia was initiated (5-15 h ipsilaterally and 15 h(-1)d contralaterally). The early activation of calpain evaluated by the generation of spectrin breakdown products (SBDP) correlated well with IL-6 up-regulation in bilateral DRGs. Double immunofluorescence staining revealed that almost all the calpain-2 positive neurons expressed IL-6, indicating an association between calpain-2 and IL-6. Inhibition of calpain by pre-treatment with MDL28170 (25mg/kg, i.p.) attenuated the rat mechanical allodynia and prevented the early up-regulation of IL-6 following L5-VRT. Addition of exogenous calpain-2 onto the surface of left L5 DRG triggered a temporal allodynia and increased IL-6 in bilateral DRGs simultaneously. Taken together, the early increase of calpain-2 in L5-VRT rats might be responsible for the induction of allodynia via up-regulating IL-6 in DRG neurons.
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Affiliation(s)
- Ying Zang
- Pain Research Center and Department of Physiology, Zhongshan Medical School of Sun Yat-Sen University, 74 Zhongshan Rd. 2, Guangzhou 510080, China.
| | - Shao-Xia Chen
- Pain Research Center and Department of Physiology, Zhongshan Medical School of Sun Yat-Sen University, 74 Zhongshan Rd. 2, Guangzhou 510080, China
| | - Guang-Jie Liao
- Pain Research Center and Department of Physiology, Zhongshan Medical School of Sun Yat-Sen University, 74 Zhongshan Rd. 2, Guangzhou 510080, China; Department of Pathology, The Red Cross Hospital of Yulin, 1 Jinwang Rd., Yulin 537000, China
| | - He-Quan Zhu
- Pain Research Center and Department of Physiology, Zhongshan Medical School of Sun Yat-Sen University, 74 Zhongshan Rd. 2, Guangzhou 510080, China
| | - Xu-Hong Wei
- Pain Research Center and Department of Physiology, Zhongshan Medical School of Sun Yat-Sen University, 74 Zhongshan Rd. 2, Guangzhou 510080, China
| | - Yu Cui
- Pain Research Center and Department of Physiology, Zhongshan Medical School of Sun Yat-Sen University, 74 Zhongshan Rd. 2, Guangzhou 510080, China
| | - Xiao-Dong Na
- Pain Research Center and Department of Physiology, Zhongshan Medical School of Sun Yat-Sen University, 74 Zhongshan Rd. 2, Guangzhou 510080, China; Department of Pathophysiology, Zhongshan Medical School of Sun Yat-Sen University, 74 Zhongshan Rd. 2, Guangzhou 510080, China
| | - Rui-Ping Pang
- Pain Research Center and Department of Physiology, Zhongshan Medical School of Sun Yat-Sen University, 74 Zhongshan Rd. 2, Guangzhou 510080, China
| | - Wen-Jun Xin
- Pain Research Center and Department of Physiology, Zhongshan Medical School of Sun Yat-Sen University, 74 Zhongshan Rd. 2, Guangzhou 510080, China
| | - Li-Jun Zhou
- Pain Research Center and Department of Physiology, Zhongshan Medical School of Sun Yat-Sen University, 74 Zhongshan Rd. 2, Guangzhou 510080, China
| | - Xian-Guo Liu
- Pain Research Center and Department of Physiology, Zhongshan Medical School of Sun Yat-Sen University, 74 Zhongshan Rd. 2, Guangzhou 510080, China
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144
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Williams PR, Marincu BN, Sorbara CD, Mahler CF, Schumacher AM, Griesbeck O, Kerschensteiner M, Misgeld T. A recoverable state of axon injury persists for hours after spinal cord contusion in vivo. Nat Commun 2014; 5:5683. [PMID: 25511170 DOI: 10.1038/ncomms6683] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2014] [Accepted: 10/28/2014] [Indexed: 01/25/2023] Open
Abstract
Therapeutic strategies for spinal cord injury (SCI) commonly focus on regenerating disconnected axons. An alternative approach would be to maintain continuity of damaged axons, especially after contusion. The viability of such neuropreservative strategies depends on the degree to which initially injured axons can recover. Here we use morphological and molecular in vivo imaging after contusion SCI in mice to show that injured axons persist in a metastable state for hours. Intra-axonal calcium dynamics influence fate, but the outcome is not invariably destructive in that many axons with calcium elevations recover homeostasis without intervention. Calcium enters axons primarily through mechanopores. Spontaneous pore resealing allows calcium levels to normalize and axons to survive long term. Axon loss can be halted by blocking calcium influx or calpain, even with delayed initiation. Our data identify an inherent self-preservation process in contused axons and a window of opportunity for rescuing connectivity after nontransecting SCI.
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Affiliation(s)
- Philip R Williams
- Institute of Neuronal Cell Biology, Technische Universität München, Munich 80802, Germany
| | - Bogdan-Nicolae Marincu
- Institute of Neuronal Cell Biology, Technische Universität München, Munich 80802, Germany
| | - Catherine D Sorbara
- 1] Institute of Neuronal Cell Biology, Technische Universität München, Munich 80802, Germany [2] Institute of Clinical Neuroimmunology, Ludwig-Maximilians Universität München, Munich 81377, Germany
| | - Christoph F Mahler
- Institute of Clinical Neuroimmunology, Ludwig-Maximilians Universität München, Munich 81377, Germany
| | - Adrian-Minh Schumacher
- Institute of Clinical Neuroimmunology, Ludwig-Maximilians Universität München, Munich 81377, Germany
| | - Oliver Griesbeck
- Max-Planck Institute of Neurobiology, Martinsried 82152, Germany
| | - Martin Kerschensteiner
- 1] Institute of Clinical Neuroimmunology, Ludwig-Maximilians Universität München, Munich 81377, Germany [2] Munich Cluster for Systems Neurology (SyNergy), Munich 81377, Germany
| | - Thomas Misgeld
- 1] Institute of Neuronal Cell Biology, Technische Universität München, Munich 80802, Germany [2] Munich Cluster for Systems Neurology (SyNergy), Munich 81377, Germany [3] Center of Integrated Protein Science (CIPSM), Munich 81377, Germany [4] German Center for Neurodegenerative Diseases (DZNE), Munich 81377, Germany
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145
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Schuldiner O, Yaron A. Mechanisms of developmental neurite pruning. Cell Mol Life Sci 2014; 72:101-19. [PMID: 25213356 DOI: 10.1007/s00018-014-1729-6] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 09/02/2014] [Accepted: 09/04/2014] [Indexed: 12/19/2022]
Abstract
The precise wiring of the nervous system is a combined outcome of progressive and regressive events during development. Axon guidance and synapse formation intertwined with cell death and neurite pruning sculpt the mature circuitry. It is now well recognized that pruning of dendrites and axons as means to refine neuronal networks, is a wide spread phenomena required for the normal development of vertebrate and invertebrate nervous systems. Here we will review the arising principles of cellular and molecular mechanisms of neurite pruning. We will discuss these principles in light of studies in multiple neuronal systems, and speculate on potential explanations for the emergence of neurite pruning as a mechanism to sculpt the nervous system.
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Affiliation(s)
- Oren Schuldiner
- Department of Molecular Cell Biology, Weizmann Institute of Sciences, 7610001, Rehovot, Israel,
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146
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Abstract
Mitochondrial dysfunction is the underlying cause of many neurological disorders, including peripheral neuropathies. Mitochondria rely on a proton gradient to generate ATP and interfering with electron transport chain function can lead to the deleterious accumulation of reactive oxygen species (ROS). Notably, loss of mitochondrial potential precedes cellular demise in several programmed cell destruction pathways, including axons undergoing Wallerian degeneration. Here, we demonstrate that mitochondrial depolarization triggers axon degeneration and cell death in primary mouse sensory neurons. These degenerative events are not blocked by inhibitors of canonical programmed cell death pathways such as apoptosis, necroptosis, and parthanatos. Instead, the axodestructive factor Sarm1 is required for this axon degeneration and cell death. In the absence of Sarm1, the mitochondrial poison CCCP still induces depolarization of mitochondria, ATP depletion, calcium influx, and the accumulation of ROS, yet cell death and axon degeneration are blocked. The survival of these neurons despite the accumulation of ROS indicates that Sarm1 acts downstream of ROS generation. Indeed, loss of Sarm1 protects sensory neurons and their axons from prolonged exposure to ROS. Therefore, Sarm1 functions downstream of ROS to induce neuronal cell death and axon degeneration during oxidative stress. These findings highlight the central role for Sarm1 in a novel form of programmed cell destruction that we term sarmoptosis.
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147
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Neukomm LJ, Freeman MR. Diverse cellular and molecular modes of axon degeneration. Trends Cell Biol 2014; 24:515-23. [PMID: 24780172 PMCID: PMC4149811 DOI: 10.1016/j.tcb.2014.04.003] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 03/30/2014] [Accepted: 04/01/2014] [Indexed: 01/11/2023]
Abstract
The elimination of large portions of axons is a widespread event in the developing and diseased nervous system. Subsets of axons are selectively destroyed to help fine-tune neural circuit connectivity during development. Axonal degeneration is also an early feature of nearly all neurodegenerative diseases, occurs after most neural injuries, and is a primary driver of functional impairment in patients. In this review we discuss the diversity of cellular mechanisms by which axons degenerate. Initial molecular characterization highlights some similarities in their execution but also argues that unique genetic programs modulate each mode of degeneration. Defining these pathways rigorously will provide new targets for therapeutic intervention after neural injury or in neurodegenerative disease.
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Affiliation(s)
- Lukas J Neukomm
- Department of Neurobiology, Howard Hughes Medical Institute, University of Massachusetts Medical School, 704 LRB, 364 Plantation Street, Worcester, MA 01609, USA
| | - Marc R Freeman
- Department of Neurobiology, Howard Hughes Medical Institute, University of Massachusetts Medical School, 704 LRB, 364 Plantation Street, Worcester, MA 01609, USA.
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148
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Pease SE, Segal RA. Preserve and protect: maintaining axons within functional circuits. Trends Neurosci 2014; 37:572-82. [PMID: 25167775 DOI: 10.1016/j.tins.2014.07.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 07/21/2014] [Accepted: 07/27/2014] [Indexed: 12/14/2022]
Abstract
During development, neural circuits are initially generated by exuberant innervation and are rapidly refined by selective preservation and elimination of axons. The establishment and maintenance of functional circuits therefore requires coordination of axon survival and degeneration pathways. Both developing and mature circuits rely on interdependent mitochondrial and cytoskeletal components to maintain axonal health and homeostasis; injury or diseases that impinge on these components frequently cause pathologic axon loss. Here, we review recent findings that identify mechanisms of axonal preservation in the contexts of development, injury, and disease.
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Affiliation(s)
- Sarah E Pease
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA; Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - Rosalind A Segal
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA; Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA.
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149
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Abstract
To explore the link between bioenergetics and motor neuron degeneration, we used a computational model in which detailed morphology and ion conductance are paired with intracellular ATP production and consumption. We found that reduced ATP availability increases the metabolic cost of a single action potential and disrupts K+/Na+ homeostasis, resulting in a chronic depolarization. The magnitude of the ATP shortage at which this ionic instability occurs depends on the morphology and intrinsic conductance characteristic of the neuron. If ATP shortage is confined to the distal part of the axon, the ensuing local ionic instability eventually spreads to the whole neuron and involves fasciculation-like spiking events. A shortage of ATP also causes a rise in intracellular calcium. Our modeling work supports the notion that mitochondrial dysfunction can account for salient features of the paralytic disorder amyotrophic lateral sclerosis, including motor neuron hyperexcitability, fasciculation, and differential vulnerability of motor neuron subpopulations.
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Affiliation(s)
- Gwendal Le Masson
- Neurocentre Magendie, INSERM U862, University of Bordeaux, 33077 Bordeaux, France; Department of Neurology, Neuro-Muscular Unit and ALS Center, CHU de Bordeaux, 33076 Bordeaux, France.
| | - Serge Przedborski
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032-3784, USA; Departments of Neurology, Pathology and Cell Biology, Columbia University, New York, NY 10032, USA.
| | - L F Abbott
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032-3784, USA; Departments of Neuroscience and Physiology and Cellular Biophysics, Columbia University, New York, NY 10032, USA
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150
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Wallerian degeneration: an emerging axon death pathway linking injury and disease. Nat Rev Neurosci 2014; 15:394-409. [DOI: 10.1038/nrn3680] [Citation(s) in RCA: 387] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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