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Peterson BS, Li J, Trujillo M, Sawardekar S, Balyozian D, Bansal S, Sun BF, Marcelino C, Nanda A, Xu T, Amen D, Bansal R. A multi-site 99mTc-HMPAO SPECT study of cerebral blood flow in a community sample of patients with major depression. Transl Psychiatry 2024; 14:234. [PMID: 38830866 PMCID: PMC11148018 DOI: 10.1038/s41398-024-02961-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 05/09/2024] [Accepted: 05/23/2024] [Indexed: 06/05/2024] Open
Abstract
Prior regional Cerebral Blood Flow (rCBF) studies in Major Depressive Disorder (MDD) have been limited by small, highly selective, non-representative samples that have yielded variable and poorly replicated findings. The aim of this study was to compare rCBF measures in a large, more representative community sample of adults with MDD and healthy control participants. This is a cross-sectional, retrospective multi-site cohort study in which clinical data from 338 patients 18-65 years of age with a primary diagnosis of MDD were retrieved from a central database for 8 privately owned, private-pay outpatient psychiatric centers across the United States. Two 99mTc-HMPAO SPECT brain scans, one at rest and one during performance of a continuous performance task, were acquired as a routine component of their initial clinical evaluation. In total, 103 healthy controls, 18-65 years old and recruited from the community were also assessed and scanned. Depressed patients had significantly higher rCBF in frontal, anterior cingulate, and association cortices, and in basal ganglia, thalamus, and cerebellum, after accounting for significantly higher overall CBF. Depression severity associated positively with rCBF in the basal ganglia, hippocampus, cerebellum, and posterior white matter. Elevated rCBF was especially prominent in women and older patients. Elevated rCBF likely represents pathogenic hypermetabolism in MDD, with its magnitude in direct proportion to depression severity. It is brain-wide, with disproportionate increases in cortical and subcortical attentional networks. Hypermetabolism may be a reasonable target for novel therapeutics in MDD.
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Affiliation(s)
- Bradley S Peterson
- Institute for the Developing Mind, Children's Hospital Los Angeles, Los Angeles, CA, USA.
- Department of Psychiatry, Keck School of Medicine at the University of Southern California, Los Angeles, CA, USA.
| | - Jennifer Li
- Institute for the Developing Mind, Children's Hospital Los Angeles, Los Angeles, CA, USA
- Department of Psychiatry, Keck School of Medicine at the University of Southern California, Los Angeles, CA, USA
| | - Manuel Trujillo
- Department of Psychiatry at NYU Grossman School of Medicine, New York, NY, USA
- Amen Clinics Inc., Costa Mesa, CA, USA
| | - Siddhant Sawardekar
- Institute for the Developing Mind, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | - David Balyozian
- Department of Psychiatry, Keck School of Medicine at the University of Southern California, Los Angeles, CA, USA
| | - Siddharth Bansal
- Institute for the Developing Mind, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | - Bernice F Sun
- Institute for the Developing Mind, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | - Courtney Marcelino
- Institute for the Developing Mind, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | - Anoop Nanda
- Institute for the Developing Mind, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | - Tracy Xu
- Institute for the Developing Mind, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | | | - Ravi Bansal
- Institute for the Developing Mind, Children's Hospital Los Angeles, Los Angeles, CA, USA
- Department of Psychiatry, Keck School of Medicine at the University of Southern California, Los Angeles, CA, USA
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2
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Wu M, Li M, Liu W, Yan M, Li L, Ding W, Nian X, Dai W, Sun D, Zhu Y, Huang Q, Lu X, Cai Z, Hong F, Li X, Zhang L, Liu Z, Mo W, Zhang X, Zhang L. Nucleoporin Seh1 maintains Schwann cell homeostasis by regulating genome stability and necroptosis. Cell Rep 2023; 42:112802. [PMID: 37453065 DOI: 10.1016/j.celrep.2023.112802] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 06/06/2023] [Accepted: 06/26/2023] [Indexed: 07/18/2023] Open
Abstract
Schwann cells play critical roles in peripheral neuropathies; however, the regulatory mechanisms of their homeostasis remain largely unknown. Here, we show that nucleoporin Seh1, a component of nuclear pore complex, is important for Schwann cell homeostasis. Expression of Seh1 decreases as mice age. Loss of Seh1 leads to activated immune responses and cell necroptosis. Mice with depletion of Seh1 in Schwann cell lineage develop progressive reduction of Schwann cells in sciatic nerves, predominantly non-myelinating Schwann cells, followed by neural fiber degeneration and malfunction of the sensory and motor system. Mechanistically, Seh1 safeguards genome stability by mediating the interaction between SETDB1 and KAP1. The disrupted interaction after ablation of Seh1 derepresses endogenous retroviruses, which triggers ZBP1-dependent necroptosis in Schwann cells. Collectively, our results demonstrate that Seh1 is required for Schwann cell homeostasis by maintaining genome integrity and suggest that decrease of nucleoporins may participate in the pathogenesis of periphery neuropathies.
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Affiliation(s)
- Mei Wu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Man Li
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Wei Liu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Minbiao Yan
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Li Li
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Weichao Ding
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Ximing Nian
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Wenxiu Dai
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Di Sun
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Yanqin Zhu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Qiuying Huang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Xiaoyun Lu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Zhiyu Cai
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Fan Hong
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Xuewen Li
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Ling Zhang
- Department of Clinic Laboratory, the affiliated Chenggong Hospital, School of Medicine, Xiamen University, Xiamen, Fujian 361102, China
| | - Zhixiong Liu
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Wei Mo
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Xueqin Zhang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Liang Zhang
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Department of Gynaecology and Obstetrics, Women and Children's Hospital Affiliated to Xiamen University, Faculty of Medicine and Life Sciences, Xiamen University, Xiamen, Fujian 361102, China.
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3
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Beirowski B. Emerging evidence for compromised axonal bioenergetics and axoglial metabolic coupling as drivers of neurodegeneration. Neurobiol Dis 2022; 170:105751. [PMID: 35569720 DOI: 10.1016/j.nbd.2022.105751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 04/20/2022] [Accepted: 05/09/2022] [Indexed: 10/18/2022] Open
Abstract
Impaired bioenergetic capacity of the nervous system is thought to contribute to the pathogenesis of many neurodegenerative diseases (NDD). Since neuronal synapses are believed to be the major energy consumers in the nervous system, synaptic derangements resulting from energy deficits have been suggested to play a central role for the development of many of these disorders. However, long axons constitute the largest compartment of the neuronal network, require large amounts of energy, are metabolically and structurally highly vulnerable, and undergo early injurious stresses in many NDD. These stresses likely impose additional energy demands for continuous adaptations and repair processes, and may eventually overwhelm axonal maintenance mechanisms. Indeed, pathological axon degeneration (pAxD) is now recognized as an etiological focus in a wide array of NDD associated with bioenergetic abnormalities. In this paper I first discuss the recognition that a simple experimental model for pAxD is regulated by an auto-destruction program that exhausts distressed axons energetically. Provision of the energy substrate pyruvate robustly counteracts this axonal breakdown. Importantly, energy decline in axons is not only a consequence but also an initiator of this program. This opens the intriguing possibility that axon dysfunction and pAxD can be suppressed by preemptively energizing distressed axons. Second, I focus on the emerging concept that axons communicate energetically with their flanking glia. This axoglial metabolic coupling can help offset the axonal energy decline that activates the pAxD program but also jeopardize axon integrity as a result of perturbed glial metabolism. Third, I present compelling evidence that abnormal axonal energetics and compromised axoglial metabolic coupling accompany the activation of the pAxD auto-destruction pathway in models of glaucoma, a widespread neurodegenerative condition with pathogenic overlap to other common NDD. In conclusion, I propose a novel conceptual framework suggesting that therapeutic interventions focused on bioenergetic support of the nervous system should also address axons and their metabolic interactions with glia.
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Affiliation(s)
- Bogdan Beirowski
- Institute for Myelin and Glia Exploration, New York State Center of Excellence in Bioinformatics & Life Sciences (CBLS), University at Buffalo, Buffalo, NY 14203, USA; Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14214, USA.
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4
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Moss KR, Bopp TS, Johnson AE, Höke A. New evidence for secondary axonal degeneration in demyelinating neuropathies. Neurosci Lett 2021; 744:135595. [PMID: 33359733 PMCID: PMC7852893 DOI: 10.1016/j.neulet.2020.135595] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 10/31/2020] [Accepted: 12/19/2020] [Indexed: 12/28/2022]
Abstract
Development of peripheral nervous system (PNS) myelin involves a coordinated series of events between growing axons and the Schwann cell (SC) progenitors that will eventually ensheath them. Myelin sheaths have evolved out of necessity to maintain rapid impulse propagation while accounting for body space constraints. However, myelinating SCs perform additional critical functions that are required to preserve axonal integrity including mitigating energy consumption by establishing the nodal architecture, regulating axon caliber by organizing axonal cytoskeleton networks, providing trophic and potentially metabolic support, possibly supplying genetic translation materials and protecting axons from toxic insults. The intermediate steps between the loss of these functions and the initiation of axon degeneration are unknown but the importance of these processes provides insightful clues. Prevalent demyelinating diseases of the PNS include the inherited neuropathies Charcot-Marie-Tooth Disease, Type 1 (CMT1) and Hereditary Neuropathy with Liability to Pressure Palsies (HNPP) and the inflammatory diseases Acute Inflammatory Demyelinating Polyneuropathy (AIDP) and Chronic Inflammatory Demyelinating Polyneuropathy (CIDP). Secondary axon degeneration is a common feature of demyelinating neuropathies and this process is often correlated with clinical deficits and long-lasting disability in patients. There is abundant electrophysiological and histological evidence for secondary axon degeneration in patients and rodent models of PNS demyelinating diseases. Fully understanding the involvement of secondary axon degeneration in these diseases is essential for expanding our knowledge of disease pathogenesis and prognosis, which will be essential for developing novel therapeutic strategies.
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Affiliation(s)
- Kathryn R Moss
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Taylor S Bopp
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Anna E Johnson
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Ahmet Höke
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD, United States.
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5
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Wilson ER, Della-Flora Nunes G, Weaver MR, Frick LR, Feltri ML. Schwann cell interactions during the development of the peripheral nervous system. Dev Neurobiol 2020; 81:464-489. [PMID: 32281247 DOI: 10.1002/dneu.22744] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Revised: 03/14/2020] [Accepted: 04/06/2020] [Indexed: 12/21/2022]
Abstract
Schwann cells play a critical role in the development of the peripheral nervous system (PNS), establishing important relationships both with the extracellular milieu and other cell types, particularly neurons. In this review, we discuss various Schwann cell interactions integral to the proper establishment, spatial arrangement, and function of the PNS. We include signals that cascade onto Schwann cells from axons and from the extracellular matrix, bidirectional signals that help to establish the axo-glial relationship and how Schwann cells in turn support the axon. Further, we speculate on how Schwann cell interactions with other components of the developing PNS ultimately promote the complete construction of the peripheral nerve.
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Affiliation(s)
- Emma R Wilson
- Hunter James Kelly Research Institute, State University of New York at Buffalo, Buffalo, NY, USA.,Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA
| | - Gustavo Della-Flora Nunes
- Hunter James Kelly Research Institute, State University of New York at Buffalo, Buffalo, NY, USA.,Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA
| | - Michael R Weaver
- Hunter James Kelly Research Institute, State University of New York at Buffalo, Buffalo, NY, USA.,Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA
| | - Luciana R Frick
- Hunter James Kelly Research Institute, State University of New York at Buffalo, Buffalo, NY, USA.,Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA
| | - M Laura Feltri
- Hunter James Kelly Research Institute, State University of New York at Buffalo, Buffalo, NY, USA.,Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA.,Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY, USA
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6
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Beirowski B. Measuring Bioenergetic Signatures of Peripheral Nerve Segments by Extracellular Flux Analysis. Methods Mol Biol 2020; 2143:191-203. [PMID: 32524482 DOI: 10.1007/978-1-0716-0585-1_15] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Changes of energy metabolism in axons and their adjacent glia as well as alterations in metabolic axon-glia cross talk are emerging as central mechanistic components underlying axon degeneration. The analysis of extracellular flux with commercial metabolic analyzers greatly facilitates the measurement of key parameters of glycolytic and mitochondrial energy metabolism in cells and tissues. In this chapter, I describe a straightforward method to capture bioenergetic profiles of acutely isolated peripheral nerve segments using the Agilent Seahorse XFe24 platform.
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Affiliation(s)
- Bogdan Beirowski
- Hunter James Kelly Research Institute, New York State Center of Excellence in Bioinformatics & Life Sciences (CBLS) RM B4-314, 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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7
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Detrimental Impact of Energy Drink Compounds on Developing Oligodendrocytes and Neurons. Cells 2019; 8:cells8111381. [PMID: 31684159 PMCID: PMC6912672 DOI: 10.3390/cells8111381] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 10/30/2019] [Accepted: 10/31/2019] [Indexed: 12/12/2022] Open
Abstract
The consumption of energy drinks is continuously rising, particularly in children and adolescents. While risks for adverse health effects, like arrhythmia, have been described, effects on neural cells remain elusive. Considering that neurodevelopmental processes like myelination and neuronal network formation peak in childhood and adolescence we hypothesized that developing oligodendrocytes and neurons are particularly vulnerable to main energy drink components. Immature oligodendrocytes and hippocampal neurons were isolated from P0-P1 Wistar rats and were incubated with 0.3 mg/mL caffeine and 4 mg/mL taurine alone or in combination for 24 h. Analysis was performed immediately after treatment or after additional three days under differentiating conditions for oligodendrocytes and standard culture for neurons. Oligodendrocyte degeneration, proliferation, and differentiation were assessed via immunocytochemistry and immunoblotting. Neuronal integrity was investigated following immunocytochemistry by analysis of dendrite outgrowth and axonal morphology. Caffeine and taurine induced an increased degeneration and inhibited proliferation of immature oligodendrocytes accompanied by a decreased differentiation capacity. Moreover, dendritic branching and axonal integrity of hippocampal neurons were negatively affected by caffeine and taurine treatment. The negative impact of caffeine and taurine on developing oligodendrocytes and disturbed neuronal morphology indicates a high risk for disturbed neurodevelopment in children and adolescents by excessive energy drink consumption.
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8
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Hao Y, Waller TJ, Nye DM, Li J, Zhang Y, Hume RI, Rolls MM, Collins CA. Degeneration of Injured Axons and Dendrites Requires Restraint of a Protective JNK Signaling Pathway by the Transmembrane Protein Raw. J Neurosci 2019; 39:8457-8470. [PMID: 31492772 PMCID: PMC6807270 DOI: 10.1523/jneurosci.0016-19.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 08/08/2019] [Accepted: 08/22/2019] [Indexed: 12/15/2022] Open
Abstract
The degeneration of injured axons involves a self-destruction pathway whose components and mechanism are not fully understood. Here, we report a new regulator of axonal resilience. The transmembrane protein Raw is cell autonomously required for the degeneration of injured axons, dendrites, and synapses in Drosophila melanogaster In both male and female raw hypomorphic mutant or knock-down larvae, the degeneration of injured axons, dendrites, and synapses from motoneurons and sensory neurons is strongly inhibited. This protection is insensitive to reduction in the levels of the NAD+ synthesis enzyme Nmnat (nicotinamide mononucleotide adenylyl transferase), but requires the c-Jun N-terminal kinase (JNK) mitogen-activated protein (MAP) kinase and the transcription factors Fos and Jun (AP-1). Although these factors were previously known to function in axonal injury signaling and regeneration, Raw's function can be genetically separated from other axonal injury responses: Raw does not modulate JNK-dependent axonal injury signaling and regenerative responses, but instead restrains a protective pathway that inhibits the degeneration of axons, dendrites, and synapses. Although protection in raw mutants requires JNK, Fos, and Jun, JNK also promotes axonal degeneration. These findings suggest the existence of multiple independent pathways that share modulation by JNK, Fos, and Jun that influence how axons respond to stress and injury.SIGNIFICANCE STATEMENT Axonal degeneration is a major feature of neuropathies and nerve injuries and occurs via a cell autonomous self-destruction pathway whose mechanism is poorly understood. This study reports the identification of a new regulator of axonal degeneration: the transmembrane protein Raw. Raw regulates a cell autonomous nuclear signaling pathway whose yet unknown downstream effectors protect injured axons, dendrites, and synapses from degenerating. These findings imply that the susceptibility of axons to degeneration is strongly regulated in neurons. Future understanding of the cellular pathway regulated by Raw, which engages the c-Jun N-terminal kinase (JNK) mitogen-activated protein (MAP) kinase and Fos and Jun transcription factors, may suggest new strategies to increase the resiliency of axons in debilitating neuropathies.
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Affiliation(s)
- Yan Hao
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-1085
| | - Thomas J Waller
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-1085
| | - Derek M Nye
- Huck Institutes of the Life Sciences, and Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, and
| | - Jiaxing Li
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-1085
| | - Yanxiao Zhang
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan 48109-2218
| | - Richard I Hume
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-1085
| | - Melissa M Rolls
- Huck Institutes of the Life Sciences, and Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, and
| | - Catherine A Collins
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-1085,
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9
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Stadelmann C, Timmler S, Barrantes-Freer A, Simons M. Myelin in the Central Nervous System: Structure, Function, and Pathology. Physiol Rev 2019; 99:1381-1431. [PMID: 31066630 DOI: 10.1152/physrev.00031.2018] [Citation(s) in RCA: 292] [Impact Index Per Article: 58.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Oligodendrocytes generate multiple layers of myelin membrane around axons of the central nervous system to enable fast and efficient nerve conduction. Until recently, saltatory nerve conduction was considered the only purpose of myelin, but it is now clear that myelin has more functions. In fact, myelinating oligodendrocytes are embedded in a vast network of interconnected glial and neuronal cells, and increasing evidence supports an active role of oligodendrocytes within this assembly, for example, by providing metabolic support to neurons, by regulating ion and water homeostasis, and by adapting to activity-dependent neuronal signals. The molecular complexity governing these interactions requires an in-depth molecular understanding of how oligodendrocytes and axons interact and how they generate, maintain, and remodel their myelin sheaths. This review deals with the biology of myelin, the expanded relationship of myelin with its underlying axons and the neighboring cells, and its disturbances in various diseases such as multiple sclerosis, acute disseminated encephalomyelitis, and neuromyelitis optica spectrum disorders. Furthermore, we will highlight how specific interactions between astrocytes, oligodendrocytes, and microglia contribute to demyelination in hereditary white matter pathologies.
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Affiliation(s)
- Christine Stadelmann
- Institute of Neuropathology, University Medical Center Göttingen , Göttingen , Germany ; Institute of Neuronal Cell Biology, Technical University Munich , Munich , Germany ; German Center for Neurodegenerative Diseases (DZNE), Munich , Germany ; Department of Neuropathology, University Medical Center Leipzig , Leipzig , Germany ; Munich Cluster of Systems Neurology (SyNergy), Munich , Germany ; and Max Planck Institute of Experimental Medicine, Göttingen , Germany
| | - Sebastian Timmler
- Institute of Neuropathology, University Medical Center Göttingen , Göttingen , Germany ; Institute of Neuronal Cell Biology, Technical University Munich , Munich , Germany ; German Center for Neurodegenerative Diseases (DZNE), Munich , Germany ; Department of Neuropathology, University Medical Center Leipzig , Leipzig , Germany ; Munich Cluster of Systems Neurology (SyNergy), Munich , Germany ; and Max Planck Institute of Experimental Medicine, Göttingen , Germany
| | - Alonso Barrantes-Freer
- Institute of Neuropathology, University Medical Center Göttingen , Göttingen , Germany ; Institute of Neuronal Cell Biology, Technical University Munich , Munich , Germany ; German Center for Neurodegenerative Diseases (DZNE), Munich , Germany ; Department of Neuropathology, University Medical Center Leipzig , Leipzig , Germany ; Munich Cluster of Systems Neurology (SyNergy), Munich , Germany ; and Max Planck Institute of Experimental Medicine, Göttingen , Germany
| | - Mikael Simons
- Institute of Neuropathology, University Medical Center Göttingen , Göttingen , Germany ; Institute of Neuronal Cell Biology, Technical University Munich , Munich , Germany ; German Center for Neurodegenerative Diseases (DZNE), Munich , Germany ; Department of Neuropathology, University Medical Center Leipzig , Leipzig , Germany ; Munich Cluster of Systems Neurology (SyNergy), Munich , Germany ; and Max Planck Institute of Experimental Medicine, Göttingen , Germany
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10
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Peterson BS, Zargarian A, Peterson JB, Goh S, Sawardekar S, Williams SCR, Lythgoe DJ, Zelaya FO, Bansal R. Hyperperfusion of Frontal White and Subcortical Gray Matter in Autism Spectrum Disorder. Biol Psychiatry 2019; 85:584-595. [PMID: 30711191 PMCID: PMC6420395 DOI: 10.1016/j.biopsych.2018.11.026] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 11/21/2018] [Accepted: 11/27/2018] [Indexed: 01/09/2023]
Abstract
BACKGROUND Our aim was to assess resting cerebral blood flow (rCBF) in children and adults with autism spectrum disorder (ASD). METHODS We acquired pulsed arterial spin labeling magnetic resonance imaging data in 44 generally high-functioning participants with ASD simplex and 66 typically developing control subjects with comparable mean full-scale IQs. We compared rCBF values voxelwise across diagnostic groups and assessed correlations with symptom scores. We also assessed the moderating influences of participant age, sex, and IQ on our findings and the correlations of rCBF with N-acetylaspartate metabolite levels. RESULTS We detected significantly higher rCBF values throughout frontal white matter and subcortical gray matter in participants with ASD. rCBF correlated positively with socialization deficits in participants with ASD in regions where hyperperfusion was greatest. rCBF declined with increasing IQ in the typically developing group, a correlation that was absent in participants with ASD, whose rCBF values were elevated across all IQ levels. rCBF in the ASD group correlated inversely with N-acetylaspartate metabolite levels throughout the frontal white matter, with greater rCBF accompanying lower and increasingly abnormal N-acetylaspartate levels relative to those of typically developing control subjects. CONCLUSIONS These findings taken together suggest the presence of altered metabolism, likely of mitochondrial origin, and dysfunctional maintenance processes that support axonal functioning in ASD. These disturbances in turn likely reduce neural efficiency for cognitive and social functioning and trigger compensatory responses from supporting glial cells, which subsequently increase rCBF to affected white matter. These findings, if confirmed, suggest cellular and molecular targets for novel therapeutics that address axonal pathology and bolster glial compensatory responses in ASD.
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Affiliation(s)
- Bradley S Peterson
- Institute for the Developing Mind, Children's Hospital Los Angeles, Los Angeles, California; Keck School of Medicine, University of Southern California, Los Angeles, California.
| | - Ariana Zargarian
- Keck School of Medicine, University of Southern California, Los Angeles, California
| | - Jarod B Peterson
- Institute for the Developing Mind, Children's Hospital Los Angeles, Los Angeles, California
| | | | - Siddhant Sawardekar
- Institute for the Developing Mind, Children's Hospital Los Angeles, Los Angeles, California
| | - Steven C R Williams
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - David J Lythgoe
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Fernando O Zelaya
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Ravi Bansal
- Institute for the Developing Mind, Children's Hospital Los Angeles, Los Angeles, California; Keck School of Medicine, University of Southern California, Los Angeles, California
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11
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Beirowski B. The LKB1-AMPK and mTORC1 Metabolic Signaling Networks in Schwann Cells Control Axon Integrity and Myelination: Assembling and upholding nerves by metabolic signaling in Schwann cells. Bioessays 2018; 41:e1800075. [PMID: 30537168 DOI: 10.1002/bies.201800075] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 11/03/2018] [Indexed: 01/10/2023]
Abstract
The Liver kinase B1 with its downstream target AMP activated protein kinase (LKB1-AMPK), and the key nutrient sensor mammalian target of rapamycin complex 1 (mTORC1) form two signaling systems that coordinate metabolic and cellular activity with changes in the environment in order to preserve homeostasis. For example, nutritional fluctuations rapidly feed back on these signaling systems and thereby affect cell-specific functions. Recent studies have started to reveal important roles of these strategic metabolic regulators in Schwann cells for the trophic support and myelination of axons. Because aberrant intermediate metabolism along with mitochondrial dysfunction in Schwann cells is mechanistically linked to nerve abnormalities found in acquired and inherited peripheral neuropathies, manipulation of the LKB1-AMPK, and mTORC1 signaling hubs may be a worthwhile therapeutic target to mitigate nerve damage in disease. Here, recent advances in our understanding of LKB1-AMPK and mTORC1 functions in Schwann cells are covered, and future research areas for this key metabolic signaling network are proposed.
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Affiliation(s)
- Bogdan Beirowski
- Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, 14203, USA.,Department of Biochemistry, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, 14214, USA
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12
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Ferrer I. Oligodendrogliopathy in neurodegenerative diseases with abnormal protein aggregates: The forgotten partner. Prog Neurobiol 2018; 169:24-54. [DOI: 10.1016/j.pneurobio.2018.07.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 07/24/2018] [Accepted: 07/27/2018] [Indexed: 12/31/2022]
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13
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Müller K, Schnatz A, Schillner M, Woertge S, Müller C, von Graevenitz I, Waisman A, van Minnen J, Vogelaar CF. A predominantly glial origin of axonal ribosomes after nerve injury. Glia 2018; 66:1591-1610. [DOI: 10.1002/glia.23327] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 02/26/2018] [Accepted: 02/27/2018] [Indexed: 01/24/2023]
Affiliation(s)
- Kerstin Müller
- Institute for Microanatomy and Neurobiology, University Medical Center of the Johannes Gutenberg University Mainz; Mainz 55131 Germany
| | - Andrea Schnatz
- Institute for Microanatomy and Neurobiology, University Medical Center of the Johannes Gutenberg University Mainz; Mainz 55131 Germany
- Institute of Developmental Biology and Neurobiology, Section Cellular Neurobiology, Johannes Gutenberg University Mainz; Mainz 55099 Germany
| | - Miriam Schillner
- Department of Neurology, Section Neuroimmunology; University Medical Center of the Johannes Gutenberg University Mainz; Mainz 55131 Germany
| | - Simone Woertge
- Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg University Mainz; Mainz 55131 Germany
| | - Christina Müller
- Institute of Developmental Biology and Neurobiology, Section Cellular Neurobiology, Johannes Gutenberg University Mainz; Mainz 55099 Germany
| | - Ilse von Graevenitz
- Institute for Microanatomy and Neurobiology, University Medical Center of the Johannes Gutenberg University Mainz; Mainz 55131 Germany
| | - Ari Waisman
- Institute for Molecular Medicine, University Medical Center of the Johannes Gutenberg University Mainz; Mainz 55131 Germany
| | - Jan van Minnen
- Hotchkiss Brain Institute and Cumming School of Medicine; University of Calgary, 3330 Hospital Drive NW; Calgary Alberta T2N 4N1 Canada
| | - Christina F. Vogelaar
- Institute for Microanatomy and Neurobiology, University Medical Center of the Johannes Gutenberg University Mainz; Mainz 55131 Germany
- Department of Neurology, Section Neuroimmunology; University Medical Center of the Johannes Gutenberg University Mainz; Mainz 55131 Germany
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14
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Belin S, Zuloaga KL, Poitelon Y. Influence of Mechanical Stimuli on Schwann Cell Biology. Front Cell Neurosci 2017; 11:347. [PMID: 29209171 PMCID: PMC5701625 DOI: 10.3389/fncel.2017.00347] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 10/19/2017] [Indexed: 12/05/2022] Open
Abstract
Schwann cells are the glial cells of the peripheral nervous system (PNS). They insulate axons by forming a specialized extension of plasma membrane called the myelin sheath. The formation of myelin is essential for the rapid saltatory propagation of action potentials and to maintain the integrity of axons. Although both axonal and extracellular matrix (ECM) signals are necessary for myelination to occur, the cellular and molecular mechanisms regulating myelination continue to be elucidated. Schwann cells in peripheral nerves are physiologically exposed to mechanical stresses (i.e., tensile, compressive and shear strains), occurring during development, adulthood and injuries. In addition, there is a growing body of evidences that Schwann cells are sensitive to the stiffness of their environment. In this review, we detail the mechanical constraints of Schwann cells and peripheral nerves. We explore the regulation of Schwann cell signaling pathways in response to mechanical stimulation. Finally, we provide a comprehensive overview of the experimental studies addressing the mechanobiology of Schwann cells. Understanding which mechanical properties can interfere with the cellular and molecular biology of Schwann cell during development, myelination and following injuries opens new insights in the regulation of PNS development and treatment approaches in peripheral neuropathies.
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Affiliation(s)
- Sophie Belin
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States
| | - Kristen L. Zuloaga
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States
| | - Yannick Poitelon
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States
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15
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Steffensen N, Lehmbecker A, Gerhauser I, Wang Y, Carlson R, Tipold A, Baumgärtner W, Stein VM. Generation and characterization of highly purified canine Schwann cells from spinal nerve dorsal roots as potential new candidates for transplantation strategies. J Tissue Eng Regen Med 2017; 12:e422-e437. [DOI: 10.1002/term.2478] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 05/06/2017] [Accepted: 05/09/2017] [Indexed: 12/15/2022]
Affiliation(s)
- Nicole Steffensen
- Department of Small Animal Medicine and Surgery; University of Veterinary Medicine; Hannover Germany
| | - Annika Lehmbecker
- Department of Pathology; University of Veterinary Medicine; Hannover Germany
- Center for Systems Neuroscience; Hannover Germany
| | - Ingo Gerhauser
- Department of Pathology; University of Veterinary Medicine; Hannover Germany
| | - Yimin Wang
- Department of Pathology; University of Veterinary Medicine; Hannover Germany
- Center for Systems Neuroscience; Hannover Germany
| | - Regina Carlson
- Department of Small Animal Medicine and Surgery; University of Veterinary Medicine; Hannover Germany
| | - Andrea Tipold
- Department of Small Animal Medicine and Surgery; University of Veterinary Medicine; Hannover Germany
- Center for Systems Neuroscience; Hannover Germany
| | - Wolfgang Baumgärtner
- Department of Pathology; University of Veterinary Medicine; Hannover Germany
- Center for Systems Neuroscience; Hannover Germany
| | - Veronika M. Stein
- Department of Small Animal Medicine and Surgery; University of Veterinary Medicine; Hannover Germany
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16
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Beirowski B, Babetto E, Wrabetz L. Axon degeneration: Linking axonal bioenergetics to myelin. J Cell Biol 2017; 215:437-440. [PMID: 27872250 PMCID: PMC5119944 DOI: 10.1083/jcb.201611010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The mechanisms by which axonal degeneration occurs, even in the presence of apparently normal myelin sheaths, remain unknown. In this issue, Yin et al. (2016. J. Cell Biol. https://doi.org/10.1083/jcb.201607099) study mutant mice in which proteolipid protein is replaced by the peripheral myelin protein P0 and describe a number of early axonal abnormalities, which together suggest that aberrant mitochondrial energy metabolism precedes axonal degeneration.
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Affiliation(s)
- Bogdan Beirowski
- Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14203
| | - Elisabetta Babetto
- Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14203
| | - Lawrence Wrabetz
- Hunter James Kelly Research Institute, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14203
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17
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Feldman EL, Nave KA, Jensen TS, Bennett DLH. New Horizons in Diabetic Neuropathy: Mechanisms, Bioenergetics, and Pain. Neuron 2017; 93:1296-1313. [PMID: 28334605 PMCID: PMC5400015 DOI: 10.1016/j.neuron.2017.02.005] [Citation(s) in RCA: 518] [Impact Index Per Article: 74.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 02/02/2017] [Accepted: 02/02/2017] [Indexed: 12/13/2022]
Abstract
Pre-diabetes and diabetes are a global epidemic, and the associated neuropathic complications create a substantial burden on both the afflicted patients and society as a whole. Given the enormity of the problem and the lack of effective therapies, there is a pressing need to understand the mechanisms underlying diabetic neuropathy (DN). In this review, we present the structural components of the peripheral nervous system that underlie its susceptibility to metabolic insults and then discuss the pathways that contribute to peripheral nerve injury in DN. We also discuss systems biology insights gleaned from the recent advances in biotechnology and bioinformatics, emerging ideas centered on the axon-Schwann cell relationship and associated bioenergetic crosstalk, and the rapid expansion of our knowledge of the mechanisms contributing to neuropathic pain in diabetes. These recent advances in our understanding of DN pathogenesis are paving the way for critical mechanism-based therapy development.
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Affiliation(s)
- Eva L Feldman
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute for Experimental Medicine, 37075 Göttingen, Germany
| | - Troels S Jensen
- Department of Neurology and Danish Pain Research Center, Aarhus University, 8000 Aarhus C, Denmark
| | - David L H Bennett
- Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford OX3 9DU, UK
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18
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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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19
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Kalheim LF, Selnes P, Bjørnerud A, Coello C, Vegge K, Fladby T. Amyloid Dysmetabolism Relates to Reduced Glucose Uptake in White Matter Hyperintensities. Front Neurol 2016; 7:209. [PMID: 27917152 PMCID: PMC5116462 DOI: 10.3389/fneur.2016.00209] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 11/08/2016] [Indexed: 12/25/2022] Open
Abstract
Alzheimer’s disease (AD) is the most prevalent neurodegenerative disorder and cause of dementia and is characterized by amyloid plaques and neurofibrillary tangles. AD has traditionally been considered to primarily affect gray matter, but multiple lines of evidence also indicate white matter (WM) pathology and associated small-vessel cerebrovascular disease. WM glucose delivery and metabolism may have implications for local tissue integrity, and [18F]-fluorodeoxyglucose positron emission tomography (FDG-PET) may be helpful to assess neuroglial and axonal function in WM. Hypothesizing that affection of oligodendroglia will be associated with loss of glucose uptake, we aimed to investigate glucose metabolism in magnetic resonance imaging (MRI) white matter hyperintensities (WMHs) and normal-appearing WM in patients with and without evidence of amyloid plaques. Subjects with mild cognitive impairment or subjective cognitive decline were included and dichotomized according to pathological (Aβ+) or normal (Aβ−) concentrations of cerebrospinal fluid amyloid-β 1–42. A total of 50 subjects were included, of whom 30 subjects were classified as Aβ(+) and 20 subjects as Aβ(−). All subjects were assessed with MRI and FDG-PET. FDG-PET images were corrected for effects of partial voluming and normalized to cerebellar WM, before determining WMH FDG-uptake. Although there were no significant differences between the groups in terms of age, WMH volume, number of individual WMHs, or WMH distribution, we found significantly lower (p = 0.021) FDG-uptake in WMHs in Aβ(+) subjects (mean = 0.662, SD = 0.113) compared to Aβ(−) subjects (mean = 0.596, SD = 0.073). There were no significant group differences in the FDG-uptake in normal-appearing WM. Similar results were obtained without correction for effects of partial voluming. Our findings add to the evidence for a link between Aβ dysmetabolism and WM pathology in AD.
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Affiliation(s)
- Lisa Flem Kalheim
- Department of Neurology, Akershus University Hospital, Lørenskog, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | - Per Selnes
- Department of Neurology, Akershus University Hospital , Lørenskog , Norway
| | - Atle Bjørnerud
- The Intervention Centre, Oslo University Hospital , Oslo , Norway
| | - Christopher Coello
- Preclinical PET/CT, Institute of Basic Medical Sciences, University of Oslo , Oslo , Norway
| | - Kjetil Vegge
- Department of Radiology, Akershus University Hospital , Lørenskog , Norway
| | - Tormod Fladby
- Department of Neurology, Akershus University Hospital, Lørenskog, Norway; Institute of Clinical Medicine, University of Oslo, Oslo, Norway
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20
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Farrar MA, Teoh HL, Brammah S, Roscioli T, Cardamone M. Glial mitochondropathy in infantile neuroaxonal dystrophy: pathophysiological and therapeutic implications. Brain 2016; 139:e67. [PMID: 27497490 DOI: 10.1093/brain/aww174] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Michelle A Farrar
- 1 Department of Neurology, Sydney Children's Hospital, Sydney, Australia .,2 Discipline of Paediatrics, School of Women's and Children's Health, UNSW Medicine, The University of New South Wales, Sydney, Australia
| | - Hooi Ling Teoh
- 1 Department of Neurology, Sydney Children's Hospital, Sydney, Australia.,2 Discipline of Paediatrics, School of Women's and Children's Health, UNSW Medicine, The University of New South Wales, Sydney, Australia
| | - Susan Brammah
- 3 Electron Microscope Unit, Anatomical Pathology, Concord Hospital, Concord, Australia
| | - Tony Roscioli
- 4 Kinghorn Centre for Clinical Genomics, Darlinghurst, NSW, Australia; GOLD Service, Royal North Shore Hospital, Sydney, Australia.,5 South Eastern Area Laboratory Services Haematology and Genetics Laboratory, Prince of Wales Hospital, Sydney, Australia.,6 Department of Medical Genetics, Sydney Children's Hospital, Sydney Australia
| | - Michael Cardamone
- 1 Department of Neurology, Sydney Children's Hospital, Sydney, Australia.,2 Discipline of Paediatrics, School of Women's and Children's Health, UNSW Medicine, The University of New South Wales, Sydney, Australia
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21
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Chen H, Yang S, Zhou T, Xu J, Hu J, Xing D. Synthesis and characterization of an HSP27-targeted nanoprobe for in vivo photoacoustic imaging of early nerve injury. NANOMEDICINE : NANOTECHNOLOGY, BIOLOGY, AND MEDICINE 2016; 12:1453-62. [PMID: 27046663 DOI: 10.1016/j.nano.2016.02.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 02/14/2016] [Accepted: 02/25/2016] [Indexed: 02/05/2023]
Abstract
Imaging is routinely used for clinical and diagnostic purposes, but techniques capable of high specificity and resolution for the early detection of nerve injury are still limited. In this study, we found that heat shock protein 27 (HSP27) becomes highly upregulated within 3 to 7 days of nerve injury. Taking advantage of this expression pattern, we conjugated gold nanorods (GNRs) to HSP27-specific antibodies to generate a nanoprobe (GNR-HSP27Abs) that could be targeted to the site of nerve injury and detected by near-infrared photoacoustic imaging. Notably, photoacoustic images acquired 12hours after local administration of GNR-HSP27Abs demonstrated that the nanoprobe can distinguish between injured and uninjured nerves in rats. Taken together, these findings expand the application of nanoprobe-targeted photoacoustic imaging to the detection of injured nerves, and prompt further development of this novel imaging platform for clinical application.
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Affiliation(s)
- Hongjiang Chen
- Department of Orthopaedics, the First Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong 515041, People's Republic of China
| | - Sihua Yang
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, People's Republic of China
| | - Ting Zhou
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, People's Republic of China
| | - Jiankun Xu
- Department of Orthopaedics, the First Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong 515041, People's Republic of China
| | - Jun Hu
- Department of Orthopaedics, the First Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong 515041, People's Republic of China; MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, People's Republic of China.
| | - Da Xing
- MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, People's Republic of China.
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22
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Voelker P, Piscopo D, Weible AP, Lynch G, Rothbart MK, Posner MI, Niell CM. How changes in white matter might underlie improved reaction time due to practice. Cogn Neurosci 2016; 8:112-118. [PMID: 27064751 DOI: 10.1080/17588928.2016.1173664] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Why does training on a task reduce the reaction time for performing it? New research points to changes in white matter pathways as one likely mechanism. These pathways connect remote brain areas involved in performing the task. Genetic variations may be involved in individual differences in the extent of this improvement. If white matter change is involved in improved reaction time with training, it may point the way toward understanding where and how generalization occurs. We examine the hypothesis that brain pathways shared by different tasks may result in improved performance of cognitive tasks remote from the training.
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Affiliation(s)
- Pascale Voelker
- a Department of Psychology , University of Oregon , Eugene , OR , USA
| | - Denise Piscopo
- b Department of Biology , University of Oregon , Eugene , OR , USA
| | - Aldis P Weible
- b Department of Biology , University of Oregon , Eugene , OR , USA.,c Institute of Neuroscience , University of Oregon , Eugene , OR , USA
| | - Gary Lynch
- d Department of Neurobiology and Behavior UC Irvine , Irvine , CA , USA
| | - Mary K Rothbart
- a Department of Psychology , University of Oregon , Eugene , OR , USA
| | - Michael I Posner
- a Department of Psychology , University of Oregon , Eugene , OR , USA.,c Institute of Neuroscience , University of Oregon , Eugene , OR , USA
| | - Cristopher M Niell
- b Department of Biology , University of Oregon , Eugene , OR , USA.,c Institute of Neuroscience , University of Oregon , Eugene , OR , USA
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23
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Abstract
Of all cellular specializations, the axon is especially distinctive because it is a narrow cylinder of specialized cytoplasm called axoplasm with a length that may be orders of magnitude greater than the diameter of the cell body from which it originates. Thus, the volume of axoplasm can be much greater than the cytoplasm in the cell body. This fact raises a logistical problem with regard to axonal maintenance. Many of the components of axoplasm, such as soluble proteins and cytoskeleton, are slowly transported, taking weeks to months to travel the length of axons longer than a few millimeters after being synthesized in the cell body. Furthermore, this slow rate of supply suggests that the axon itself might not have the capacity to respond fast enough to compensate for damage to transported macromolecules. Such damage is likely in view of the mechanical fragility of an axon, especially those innervating the limbs, as rapid limb motion with high impact, like running, subjects the axons in the limbs to considerable mechanical force. Some researchers have suggested that local, intra-axonal protein synthesis is the answer to this problem. However, the translational state of axonal RNAs remains controversial. We suggest that glial cells, which envelop all axons, whether myelinated or not, are the local sources of replacement and repair macromolecules for long axons. The plausibility of this hypothesis is reinforced by reviewing several decades of work on glia-axon macromolecular transfer, together with recent investigations of exosomes and other extracellular vesicles, as vehicles for the transmission of membrane and cytoplasmic components from one cell to another.
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Affiliation(s)
- Michael Tytell
- Department of Neurobiology and Anatomy, Wake Forest University School of Medicine, Winston-Salem, NC, 27157, USA; Marine Biological Laboratory, Marine Biological Laboratory, Woods Hole, MA, 02543, USA
| | - Raymond J Lasek
- Department of Anatomy, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
| | - Harold Gainer
- Laboratory of Neurochemistry, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, 20892, USA; Marine Biological Laboratory, Marine Biological Laboratory, Woods Hole, MA, 02543, USA
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24
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Dutta S, Rieche F, Eckl N, Duch C, Kretzschmar D. Glial expression of Swiss cheese (SWS), the Drosophila orthologue of neuropathy target esterase (NTE), is required for neuronal ensheathment and function. Dis Model Mech 2015; 9:283-94. [PMID: 26634819 PMCID: PMC4826977 DOI: 10.1242/dmm.022236] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 11/26/2015] [Indexed: 01/04/2023] Open
Abstract
Mutations in Drosophila Swiss cheese (SWS) or its vertebrate orthologue neuropathy target esterase (NTE), respectively, cause progressive neuronal degeneration in Drosophila and mice and a complex syndrome in humans that includes mental retardation, spastic paraplegia and blindness. SWS and NTE are widely expressed in neurons but can also be found in glia; however, their function in glia has, until now, remained unknown. We have used a knockdown approach to specifically address SWS function in glia and to probe for resulting neuronal dysfunctions. This revealed that loss of SWS in pseudocartridge glia causes the formation of multi-layered glial whorls in the lamina cortex, the first optic neuropil. This phenotype was rescued by the expression of SWS or NTE, suggesting that the glial function is conserved in the vertebrate protein. SWS was also found to be required for the glial wrapping of neurons by ensheathing glia, and its loss in glia caused axonal damage. We also detected severe locomotion deficits in glial sws-knockdown flies, which occurred as early as 2 days after eclosion and increased further with age. Utilizing the giant fibre system to test for underlying functional neuronal defects showed that the response latency to a stimulus was unchanged in knockdown flies compared to controls, but the reliability with which the neurons responded to increasing frequencies was reduced. This shows that the loss of SWS in glia impairs neuronal function, strongly suggesting that the loss of glial SWS plays an important role in the phenotypes observed in the sws mutant. It is therefore likely that changes in glia also contribute to the pathology observed in humans that carry mutations in NTE.
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Affiliation(s)
- Sudeshna Dutta
- Oregon Institute of Occupational Health Sciences, Oregon Health & Sciences University, Portland, OR 97239, USA
| | - Franziska Rieche
- Institut für Zoologie III - Neurobiologie, Universität Mainz, Colonel-Kleinmann-Weg 2, Mainz D-55099, Germany
| | - Nina Eckl
- Institut für Zoologie III - Neurobiologie, Universität Mainz, Colonel-Kleinmann-Weg 2, Mainz D-55099, Germany
| | - Carsten Duch
- Institut für Zoologie III - Neurobiologie, Universität Mainz, Colonel-Kleinmann-Weg 2, Mainz D-55099, Germany
| | - Doris Kretzschmar
- Oregon Institute of Occupational Health Sciences, Oregon Health & Sciences University, Portland, OR 97239, USA
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25
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26
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Menezes MP, Farrar MA, Webster R, Antony J, O'Brien K, Ouvrier R, Kiernan MC, Burns J, Vucic S. Pathophysiology of motor dysfunction in a childhood motor neuron disease caused by mutations in the riboflavin transporter. Clin Neurophysiol 2015; 127:911-918. [PMID: 26092362 DOI: 10.1016/j.clinph.2015.05.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 05/19/2015] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Brown-Vialetto-Van Laere (BVVL) syndrome is a progressive motor and sensory neuronopathy secondary to mutations in SLC52A2 encoding the riboflavin transporter type 2 (RFVT2). The phenotype is characterized by early childhood onset hearing loss and sensory ataxia followed by progressive upper limb weakness, optic atrophy, bulbar weakness and respiratory failure. To gain further insight into disease pathophysiology and response to riboflavin supplementation, the present study investigated whether axonal ion channel or membrane abnormalities were a feature of BVVL. METHODS Axonal excitability studies and clinical assessments were prospectively undertaken on six patients with BVVL secondary to riboflavin transporter deficiency type 2 (age range 10-21 years) at baseline and after 12 months of riboflavin (1000 mg daily) therapy. RESULTS At baseline, depolarizing and hyperpolarizing threshold electrotonus was 'fanned out' and superexcitability was increased, while the resting current-threshold gradient and refractoriness were significantly reduced in BVVL patients when compared to controls. Mathematical modeling suggested that functional alterations of myelin underlay these findings with an increase in myelin permeability. Riboflavin therapy resulted in partial normalization of the axonal excitability findings, paralleled by maintenance of muscle strength. CONCLUSIONS The present study established that abnormalities in myelin permeability at the paranode was a feature of BVVL and were partially normalized with riboflavin therapy. SIGNIFICANCE This study reveals a novel pathophysiological process for motor nerve dysfunction in BVVL. It also indicates that nerve excitability studies may be further developed in larger cohorts as a potential biomarker to identify treatment response for BVVL patients.
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Affiliation(s)
- Manoj P Menezes
- Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, Australia; Discipline of Paediatrics and Child Health, The Children's Hospital at Westmead Clinical School, The University of Sydney, Sydney, Australia; Department of Neurology, The Children's Hospital at Westmead, Sydney, Australia
| | - Michelle A Farrar
- Discipline of Paediatrics, School of Women's and Children's Health, UNSW Medicine, The University of New South Wales, Sydney, Australia; Neurosciences Research Australia, Sydney, Australia; Department of Neurology, Sydney Children's Hospital, Sydney, Australia.
| | - Richard Webster
- Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, Australia; Department of Neurology, The Children's Hospital at Westmead, Sydney, Australia
| | - Jayne Antony
- Department of Neurology, The Children's Hospital at Westmead, Sydney, Australia
| | - Katherine O'Brien
- Department of Audiology, The Children's Hospital at Westmead, Sydney, Australia
| | - Robert Ouvrier
- Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, Australia; Discipline of Paediatrics and Child Health, The Children's Hospital at Westmead Clinical School, The University of Sydney, Sydney, Australia; Department of Neurology, The Children's Hospital at Westmead, Sydney, Australia
| | - Matthew C Kiernan
- Neurosciences Research Australia, Sydney, Australia; Sydney Medical School, Brain & Mind Research Institute, University of Sydney, Sydney, Australia
| | - Joshua Burns
- Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, Australia; Paediatric Gait Analysis Service of New South Wales, Sydney Children's Hospitals Network, Sydney, Australia; Sydney Arthritis and Musculoskeletal Research Network, The University of Sydney, Sydney, Australia
| | - Steve Vucic
- Department of Neurology, Westmead Hospital and Western Clinical School, University of Sydney, Sydney, Australia
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Nakamura K, Mori F, Kon T, Tanji K, Miki Y, Tomiyama M, Kurotaki H, Toyoshima Y, Kakita A, Takahashi H, Yamada M, Wakabayashi K. Filamentous aggregations of phosphorylated α-synuclein in Schwann cells (Schwann cell cytoplasmic inclusions) in multiple system atrophy. Acta Neuropathol Commun 2015; 3:29. [PMID: 25990096 PMCID: PMC4438578 DOI: 10.1186/s40478-015-0208-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 04/30/2015] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND The histological hallmark of multiple system atrophy (MSA) is the presence of filamentous aggregations of phosphorylated α-synuclein in oligodendrocytes, referred to as glial cytoplasmic inclusions (GCIs). Although GCIs can occur widely in the central nervous system, accumulation of phosphorylated α-synuclein in Schwann cells has not been reported in MSA. We immunohistochemically examined the cranial and spinal nerves, peripheral ganglia and visceral autonomic nervous system of patients with MSA (n = 14) and control subjects (n = 20). RESULTS In MSA, accumulation of phosphorylated α-synuclein was found in the cytoplasm of Schwann cells. These Schwann cell cytoplasmic inclusions (SCCIs) were also immunopositive for ubiquitin and p62. SCCIs were found in 12 of 14 patients with MSA (85.7 %). They were most frequent in the anterior nerve of the sacral cord and, to a lesser extent, in the cranial nerves (oculomotor, glossopharyngeal-vagus and hypoglossal nerves), and spinal and sympathetic ganglia. SCCIs were rarely found in the visceral organs. Immunoelectron microscopy demonstrated that the SCCIs consisted of abnormal filaments, 15-20 nm in diameter. No such inclusions were found in controls. CONCLUSION The present findings indicate that Schwann cells are also involved in the disease process of MSA.
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Oligodendroglia and Myelin in Neurodegenerative Diseases: More Than Just Bystanders? Mol Neurobiol 2015; 53:3046-3062. [PMID: 25966971 PMCID: PMC4902834 DOI: 10.1007/s12035-015-9205-3] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 04/29/2015] [Indexed: 12/01/2022]
Abstract
Oligodendrocytes, the myelinating cells of the central nervous system, mediate rapid action potential conduction and provide trophic support for axonal as well as neuronal maintenance. Their progenitor cell population is widely distributed in the adult brain and represents a permanent cellular reservoir for oligodendrocyte replacement and myelin plasticity. The recognition of oligodendrocytes, their progeny, and myelin as contributing factors for the pathogenesis and the progression of neurodegenerative disease has recently evolved shaping our understanding of these disorders. In the present review, we aim to highlight studies on oligodendrocytes and their progenitors in neurodegenerative diseases. We dissect oligodendroglial biology and illustrate evolutionary aspects in regard to their importance for neuronal functionality and maintenance of neuronal circuitries. After covering recent studies on oligodendroglia in different neurodegenerative diseases mainly in view of their function as myelinating cells, we focus on the alpha-synucleinopathy multiple system atrophy, a prototypical disorder with a well-defined oligodendroglial pathology.
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Xiao Y, Faucherre A, Pola-Morell L, Heddleston JM, Liu TL, Chew TL, Sato F, Sehara-Fujisawa A, Kawakami K, López-Schier H. High-resolution live imaging reveals axon-glia interactions during peripheral nerve injury and repair in zebrafish. Dis Model Mech 2015; 8:553-64. [PMID: 26035865 PMCID: PMC4457030 DOI: 10.1242/dmm.018184] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 03/24/2015] [Indexed: 12/22/2022] Open
Abstract
Neural damage is a devastating outcome of physical trauma. The glia are one of the main effectors of neuronal repair in the nervous system, but the dynamic interactions between peripheral neurons and Schwann cells during injury and regeneration remain incompletely characterized. Here, we combine laser microsurgery, genetic analysis, high-resolution intravital imaging and lattice light-sheet microscopy to study the interaction between Schwann cells and sensory neurons in a zebrafish model of neurotrauma. We found that chronic denervation by neuronal ablation leads to Schwann-cell death, whereas acute denervation by axonal severing does not affect the overall complexity and architecture of the glia. Neuronal-circuit regeneration begins when Schwann cells extend bridging processes to close the injury gap. Regenerating axons grow faster and directionally after the physiological clearing of distal debris by the Schwann cells. This might facilitate circuit repair by ensuring that axons are guided through unoccupied spaces within bands of Büngner towards their original peripheral target. Accordingly, in the absence of Schwann cells, regenerating axons are misrouted, impairing the re-innervation of sensory organs. Our results indicate that regenerating axons use haptotaxis as a directional cue during the reconstitution of a neural circuit. These findings have implications for therapies aimed at neurorepair, which will benefit from preserving the architecture of the peripheral glia during periods of denervation. Summary: Schwann cells are important components of the peripheral glia. We use microsurgery and high-resolution live imaging to show how Schwann cells control the regeneration of a sensorineural circuit.
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Affiliation(s)
- Yan Xiao
- Research Unit Sensory Biology & Organogenesis, Helmholtz Zentrum München, 85764 Munich, Germany
| | - Adèle Faucherre
- Cell & Developmental Biology, Centre for Genomic Regulation, 08003 Barcelona, Spain
| | - Laura Pola-Morell
- Cell & Developmental Biology, Centre for Genomic Regulation, 08003 Barcelona, Spain
| | - John M Heddleston
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Tsung-Li Liu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Teng-Leong Chew
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Fuminori Sato
- Institute for Frontier Medical Sciences, Kyoto University, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
| | - Atsuko Sehara-Fujisawa
- Institute for Frontier Medical Sciences, Kyoto University, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan
| | - Koichi Kawakami
- Division of Molecular and Developmental Biology, National Institute of Genetics, The Graduate University for Advanced Studies (Sokendai), 1111 Yata, Mishima, Shizuoka 411-8540, Japan Department of Genetics, The Graduate University for Advanced Studies (Sokendai), 1111 Yata, Mishima, Shizuoka 411-8540, Japan
| | - Hernán López-Schier
- Research Unit Sensory Biology & Organogenesis, Helmholtz Zentrum München, 85764 Munich, Germany Cell & Developmental Biology, Centre for Genomic Regulation, 08003 Barcelona, Spain
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Tavares L, Pereira E, Correia A, Santos MA, Amaral N, Martins T, Relvas JB, Pereira PS. Drosophila PS2 and PS3 integrins play distinct roles in retinal photoreceptors-glia interactions. Glia 2015; 63:1155-65. [PMID: 25731761 DOI: 10.1002/glia.22806] [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] [Received: 09/23/2014] [Accepted: 01/28/2015] [Indexed: 11/09/2022]
Abstract
Cellular migration and differentiation are important developmental processes that require dynamic cellular adhesion. Integrins are heterodimeric transmembrane receptors that play key roles in adhesion plasticity. Here, we explore the developing visual system of Drosophila to study the roles of integrin heterodimers in glia development. Our data show that αPS2 is essential for retinal glia migration from the brain into the eye disc and that glial cells have a role in the maintenance of the fenestrated membrane (Laminin-rich ECM layer) in the disc. Interestingly, the absence of glial cells in the eye disc did not affect the targeting of retinal axons to the optic stalk. In contrast, αPS3 is not required for retinal glia migration, but together with Talin, it functions in glial cells to allow photoreceptor axons to target the optic stalk. Thus, we present evidence that αPS2 and αPS3 integrin have different and specific functions in the development of retinal glia.
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Affiliation(s)
- Lígia Tavares
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Portugal; IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Portugal
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Posner MI, Tang YY, Lynch G. Mechanisms of white matter change induced by meditation training. Front Psychol 2014; 5:1220. [PMID: 25386155 PMCID: PMC4209813 DOI: 10.3389/fpsyg.2014.01220] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 10/08/2014] [Indexed: 12/12/2022] Open
Abstract
Training can induce changes in specific brain networks and changes in brain state. In both cases it has been found that the efficiency of white matter as measured by diffusion tensor imaging is increased, often after only a few hours of training. In this paper we consider a plausible molecular mechanism for how state change produced by meditation might lead to white matter change. According to this hypothesis frontal theta induced by meditation produces a molecular cascade that increases myelin and improves connectivity.
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Affiliation(s)
| | - Yi-Yuan Tang
- Department of Psychological Sciences, Texas Tech University Lubbock, TX, USA
| | - Gary Lynch
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine Irvine, CA, USA
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Beirowski B, Babetto E, Golden JP, Chen YJ, Yang K, Gross RW, Patti GJ, Milbrandt J. Metabolic regulator LKB1 is crucial for Schwann cell-mediated axon maintenance. Nat Neurosci 2014; 17:1351-61. [PMID: 25195104 DOI: 10.1038/nn.3809] [Citation(s) in RCA: 143] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 08/15/2014] [Indexed: 02/06/2023]
Abstract
Schwann cells (SCs) promote axonal integrity independently of myelination by poorly understood mechanisms. Current models suggest that SC metabolism is critical for this support function and that SC metabolic deficits may lead to axonal demise. The LKB1-AMP-activated protein kinase (AMPK) kinase pathway targets several downstream effectors, including mammalian target of rapamycin (mTOR), and is a key metabolic regulator implicated in metabolic diseases. We found through molecular, structural and behavioral characterization of SC-specific mutant mice that LKB1 activity is central to axon stability, whereas AMPK and mTOR in SCs are largely dispensable. The degeneration of axons in LKB1 mutants was most dramatic in unmyelinated small sensory fibers, whereas motor axons were comparatively spared. LKB1 deletion in SCs led to abnormalities in nerve energy and lipid homeostasis and to increased lactate release. The latter acts in a compensatory manner to support distressed axons. LKB1 signaling is essential for SC-mediated axon support, a function that may be dysregulated in diabetic neuropathy.
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Affiliation(s)
- Bogdan Beirowski
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Elisabetta Babetto
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Judith P Golden
- Department of Anesthesiology, Washington University Pain Center, St. Louis, Missouri, USA
| | - Ying-Jr Chen
- Department of Chemistry, Washington University, St. Louis, Missouri, USA
| | - Kui Yang
- Department of Internal Medicine, Division of Bioorganic Chemistry and Molecular Pharmacology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Richard W Gross
- Department of Internal Medicine, Division of Bioorganic Chemistry and Molecular Pharmacology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Gary J Patti
- 1] Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, USA. [2] Department of Chemistry, Washington University, St. Louis, Missouri, USA. [3] Department of Internal Medicine, Division of Bioorganic Chemistry and Molecular Pharmacology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Jeffrey Milbrandt
- 1] Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, USA. [2] Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri, USA
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Defining Peripheral Nervous System Dysfunction in the SOD-1G93ATransgenic Rat Model of Amyotrophic Lateral Sclerosis. J Neuropathol Exp Neurol 2014; 73:658-70. [DOI: 10.1097/nen.0000000000000081] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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