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Mishra SK, Tiwari SP. Bioenergetics of Axon Integrity and Its Regulation by Oligodendrocytes and Schwann Cells. Mol Neurobiol 2024; 61:5928-5934. [PMID: 38252382 DOI: 10.1007/s12035-024-03950-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 01/09/2024] [Indexed: 01/23/2024]
Abstract
Axons are long slender portions of neurons that transmit electrical impulses to maintain proper physiological functioning. Axons in the central nervous system (CNS) and peripheral nervous system (PNS) do not exist in isolation but are found to form a complex association with their surrounding glial cells, oligodendrocytes and Schwann cells. These cells not only myelinate them for faster nerve impulse conduction but are also known to provide metabolic support. Due to their incredible length, continuous growth, and distance from the cell body (where major energy synthesis takes place), axons are in high energetic demand. The stability and integrity of axons have long been associated with axonal energy levels. The current mini-review is thus focused on how axons accomplish their high energetic requirement in a cell-autonomous manner and how the surrounding glial cells help them in maintaining their integrity by fulfilling their energy demands (non-cell autonomous trophic support). The concept that adjacent glial cells (oligodendrocytes and Schwann cells) provide trophic support to axons and assist them in maintaining their integrity comes from the conditional knockout research and the studies in which the metabolic pathways controlling metabolism in these glial cells are modulated and its effect on axonal integrity is evaluated. In the later part of the mini-review, the current knowledge of axon-glial metabolic coupling during various neurodegenerative conditions was discussed, along with the potential lacunae in our current understanding of axon-glial metabolic coupling.
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Affiliation(s)
- Sandeep K Mishra
- Institute for Myelin and Glia Exploration, University at Buffalo, Buffalo, NY, 14203, USA.
- Faculty of Pharmacy, Kalinga University, Raipur, (C.G.), 492101, India.
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2
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Lemche E, Killick R, Mitchell J, Caton PW, Choudhary P, Howard JK. Molecular mechanisms linking type 2 diabetes mellitus and late-onset Alzheimer's disease: A systematic review and qualitative meta-analysis. Neurobiol Dis 2024; 196:106485. [PMID: 38643861 DOI: 10.1016/j.nbd.2024.106485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 03/18/2024] [Accepted: 03/23/2024] [Indexed: 04/23/2024] Open
Abstract
Research evidence indicating common metabolic mechanisms through which type 2 diabetes mellitus (T2DM) increases risk of late-onset Alzheimer's dementia (LOAD) has accumulated over recent decades. The aim of this systematic review is to provide a comprehensive review of common mechanisms, which have hitherto been discussed in separate perspectives, and to assemble and evaluate candidate loci and epigenetic modifications contributing to polygenic risk linkages between T2DM and LOAD. For the systematic review on pathophysiological mechanisms, both human and animal studies up to December 2023 are included. For the qualitative meta-analysis of genomic bases, human association studies were examined; for epigenetic mechanisms, data from human studies and animal models were accepted. Papers describing pathophysiological studies were identified in databases, and further literature gathered from cited work. For genomic and epigenomic studies, literature mining was conducted by formalised search codes using Boolean operators in search engines, and augmented by GeneRif citations in Entrez Gene, and other sources (WikiGenes, etc.). For the systematic review of pathophysiological mechanisms, 923 publications were evaluated, and 138 gene loci extracted for testing candidate risk linkages. 3 57 publications were evaluated for genomic association and descriptions of epigenomic modifications. Overall accumulated results highlight insulin signalling, inflammation and inflammasome pathways, proteolysis, gluconeogenesis and glycolysis, glycosylation, lipoprotein metabolism and oxidation, cell cycle regulation or survival, autophagic-lysosomal pathways, and energy. Documented findings suggest interplay between brain insulin resistance, neuroinflammation, insult compensatory mechanisms, and peripheral metabolic dysregulation in T2DM and LOAD linkage. The results allow for more streamlined longitudinal studies of T2DM-LOAD risk linkages.
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Affiliation(s)
- Erwin Lemche
- Section of Cognitive Neuropsychiatry and Centre for Neuroimaging Sciences, Institute of Psychiatry, Psychology & Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, United Kingdom.
| | - Richard Killick
- Section of Old Age Psychiatry, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology & Neuroscience, King's College London, De Crespigny Park, London SE5 8AF, United Kingdom
| | - Jackie Mitchell
- Department of Basic and Clinical Neurosciences, Maurice Wohl CIinical Neurosciences Institute, Institute of Psychiatry, Psychology & Neuroscience, King's College London, 125 Coldharbour Lane, London SE5 9NU, United Kingdom
| | - Paul W Caton
- Diabetes Research Group, School of Life Course Sciences, King's College London, Hodgkin Building, Guy's Campus, London SE1 1UL, United Kingdom
| | - Pratik Choudhary
- Diabetes Research Group, Weston Education Centre, King's College London, 10 Cutcombe Road, London SE5 9RJ, United Kingdom
| | - Jane K Howard
- School of Cardiovascular and Metabolic Medicine & Sciences, Hodgkin Building, Guy's Campus, King's College London, Great Maze Pond, London SE1 1UL, United Kingdom
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3
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Lv Y, Yao X, Li X, Ouyang Y, Fan C, Qian Y. Cell metabolism pathways involved in the pathophysiological changes of diabetic peripheral neuropathy. Neural Regen Res 2024; 19:598-605. [PMID: 37721290 PMCID: PMC10581560 DOI: 10.4103/1673-5374.380872] [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: 01/11/2023] [Revised: 03/31/2023] [Accepted: 06/08/2023] [Indexed: 09/19/2023] Open
Abstract
Diabetic peripheral neuropathy is a common complication of diabetes mellitus. Elucidating the pathophysiological metabolic mechanism impels the generation of ideal therapies. However, existing limited treatments for diabetic peripheral neuropathy expose the urgent need for cell metabolism research. Given the lack of comprehensive understanding of energy metabolism changes and related signaling pathways in diabetic peripheral neuropathy, it is essential to explore energy changes and metabolic changes in diabetic peripheral neuropathy to develop suitable treatment methods. This review summarizes the pathophysiological mechanism of diabetic peripheral neuropathy from the perspective of cellular metabolism and the specific interventions for different metabolic pathways to develop effective treatment methods. Various metabolic mechanisms (e.g., polyol, hexosamine, protein kinase C pathway) are associated with diabetic peripheral neuropathy, and researchers are looking for more effective treatments through these pathways.
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Affiliation(s)
- Yaowei Lv
- Department of Orthopedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Engineering Research Center for Orthopaedic Material Innovation and Tissue Regeneration, Shanghai, China
| | - Xiangyun Yao
- Department of Orthopedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Engineering Research Center for Orthopaedic Material Innovation and Tissue Regeneration, Shanghai, China
- Youth Science and Technology Innovation Studio of Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiao Li
- Department of Orthopedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Engineering Research Center for Orthopaedic Material Innovation and Tissue Regeneration, Shanghai, China
- College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, China
| | - Yuanming Ouyang
- Department of Orthopedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Engineering Research Center for Orthopaedic Material Innovation and Tissue Regeneration, Shanghai, China
- Youth Science and Technology Innovation Studio of Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Cunyi Fan
- Department of Orthopedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Engineering Research Center for Orthopaedic Material Innovation and Tissue Regeneration, Shanghai, China
- Youth Science and Technology Innovation Studio of Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yun Qian
- Department of Orthopedics, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai Engineering Research Center for Orthopaedic Material Innovation and Tissue Regeneration, Shanghai, China
- Youth Science and Technology Innovation Studio of Shanghai Jiao Tong University School of Medicine, Shanghai, China
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4
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Sheloukhova L, Watanabe H. Analysis of cnidarian Gcm suggests a neuronal origin of glial EAAT1 function. Sci Rep 2023; 13:14790. [PMID: 37684386 PMCID: PMC10491807 DOI: 10.1038/s41598-023-42046-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 09/04/2023] [Indexed: 09/10/2023] Open
Abstract
In bilaterian central nervous systems, coordination of neurotransmission by glial cells enables highly sophisticated neural functions. The diversity of transcription factors (TFs) involved in gliogenesis suggests multiple evolutionary origins of various glial cell types of bilaterians. Many of these TFs including the glial cells missing (Gcm) are also present in genomes of Cnidaria, the closest outgroup to Bilateria, but their function remains to be elucidated. In this study, we analyzed the function of Gcm, a multifunctional TF involved in development of glial and non-glial cell types, in the sea anemone, Nematostella vectensis. siRNA-mediated knockdown of Nematostella Gcm altered expression of cell adhesion proteins, glutamate and GABA transporters, ion channels, metabolic enzymes, and zinc finger and Ets-related TFs. NvGcm and mRNAs of downstream genes are expressed in broad neural cell clusters. However, immunostaining of a NvGcm target protein, the glutamate transporter, NvEAAT1, visualized a novel class of cells with flat cell bodies and no clear processes. Together with the finding of unique morphological features of NvEAAT1-functioning cells, these data suggest that extracellular glutamate metabolism, one of major glial functions, is deployed downstream of Gcm in specific neural cell types in Cnidaria.
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Affiliation(s)
- Larisa Sheloukhova
- Evolutionary Neurobiology Unit, Okinawa Institute of Science and Technology, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0412, Japan
| | - Hiroshi Watanabe
- Evolutionary Neurobiology Unit, Okinawa Institute of Science and Technology, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0412, Japan.
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5
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Dong X, Shu L, Zhang J, Yang X, Cheng X, Zhao X, Qu W, Zhu Q, Shou Y, Peng G, Sun B, Yi W, Shu Q, Li X. Ogt-mediated O-GlcNAcylation inhibits astrocytes activation through modulating NF-κB signaling pathway. J Neuroinflammation 2023; 20:146. [PMID: 37349834 DOI: 10.1186/s12974-023-02824-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 06/05/2023] [Indexed: 06/24/2023] Open
Abstract
Previous studies have shown that Ogt-mediated O-GlcNAcylation is essential for neuronal development and function. However, the function of O-GlcNAc transferase (Ogt) and O-GlcNAcylation in astrocytes remains largely unknown. Here we show that Ogt deficiency induces inflammatory activation of astrocytes in vivo and in vitro, and impairs cognitive function of mice. The restoration of O-GlcNAcylation via GlcNAc supplementation inhibits the activation of astrocytes, inflammation and improves the impaired cognitive function of Ogt deficient mice. Mechanistically, Ogt interacts with NF-κB p65 and catalyzes the O-GlcNAcylation of NF-κB p65 in astrocytes. Ogt deficiency induces the activation of NF-κB signaling pathway by promoting Gsk3β binding. Moreover, Ogt depletion induces the activation of astrocytes derived from human induced pluripotent stem cells. The restoration of O-GlcNAcylation inhibits the activation of astrocytes, inflammation and reduces Aβ plaque of AD mice in vitro and in vivo. Collectively, our study reveals a critical function of Ogt-mediated O-GlcNAcylation in astrocytes through regulating NF-κB signaling pathway.
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Affiliation(s)
- Xiaoxue Dong
- The Children's Hospital, National Clinical Research Center for Child Health, School of Medicine, Zhejiang University, Hangzhou, 310052, China
- The Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou, 310029, China
| | - Liqi Shu
- Department of Neurology, The Warren Alpert Medical School of Brown University, Providence, RI, 02908, USA
| | - Jinyu Zhang
- The Children's Hospital, National Clinical Research Center for Child Health, School of Medicine, Zhejiang University, Hangzhou, 310052, China
- The Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou, 310029, China
| | - Xu Yang
- The Children's Hospital, National Clinical Research Center for Child Health, School of Medicine, Zhejiang University, Hangzhou, 310052, China
- The Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou, 310029, China
| | - Xuejun Cheng
- The Children's Hospital, National Clinical Research Center for Child Health, School of Medicine, Zhejiang University, Hangzhou, 310052, China
| | - Xingsen Zhao
- The Children's Hospital, National Clinical Research Center for Child Health, School of Medicine, Zhejiang University, Hangzhou, 310052, China
- The Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou, 310029, China
| | - Wenzheng Qu
- The Children's Hospital, National Clinical Research Center for Child Health, School of Medicine, Zhejiang University, Hangzhou, 310052, China
| | - Qiang Zhu
- MOE Key Laboratory of Biosystems Homeostasis & Protection, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Yikai Shou
- The Children's Hospital, National Clinical Research Center for Child Health, School of Medicine, Zhejiang University, Hangzhou, 310052, China
| | - Guoping Peng
- The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Binggui Sun
- The Children's Hospital, National Clinical Research Center for Child Health, School of Medicine, Zhejiang University, Hangzhou, 310052, China.
- NHC and CAMS Key Laboratory of Medical Neurobiology, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, 310058, Zhejiang, China.
| | - Wen Yi
- MOE Key Laboratory of Biosystems Homeostasis & Protection, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China.
| | - Qiang Shu
- The Children's Hospital, National Clinical Research Center for Child Health, School of Medicine, Zhejiang University, Hangzhou, 310052, China.
| | - Xuekun Li
- The Children's Hospital, National Clinical Research Center for Child Health, School of Medicine, Zhejiang University, Hangzhou, 310052, China.
- The Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou, 310029, China.
- Zhejiang University Cancer Center, Zhejiang University, Hangzhou, 310029, China.
- Binjiang Institute of Zhejiang University, Hangzhou, 310053, China.
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6
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Zhang J, Wei K, Qu W, Wang M, Zhu Q, Dong X, Huang X, Yi W, Xu S, Li X. Ogt Deficiency Induces Abnormal Cerebellar Function and Behavioral Deficits of Adult Mice through Modulating RhoA/ROCK Signaling. J Neurosci 2023; 43:4559-4579. [PMID: 37225434 PMCID: PMC10286951 DOI: 10.1523/jneurosci.1962-22.2023] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 04/10/2023] [Accepted: 04/13/2023] [Indexed: 05/26/2023] Open
Abstract
Previous studies have shown the essential roles of O-GlcNAc transferase (Ogt) and O-GlcNAcylation in neuronal development, function and neurologic diseases. However, the function of Ogt and O-GlcNAcylation in the adult cerebellum has not been well elucidated. Here, we have found that cerebellum has the highest level of O-GlcNAcylation relative to cortex and hippocampus of adult male mice. Specific deletion of Ogt in granule neuron precursors (GNPs) induces abnormal morphology and decreased size of the cerebellum in adult male Ogt deficient [conditional knock-out (cKO)] mice. Adult male cKO mice show the reduced density and aberrant distribution of cerebellar granule cells (CGCs), the disrupted arrangement of Bergman glia (BG) and Purkinje cells. In addition, adult male cKO mice exhibit aberrant synaptic connection, impaired motor coordination, and learning and memory abilities. Mechanistically, we have identified G-protein subunit α12 (Gα12) is modified by Ogt-mediated O-GlcNAcylation. O-GlcNAcylation of Gα12 facilitates its binding to Rho guanine nucleotide exchange factor 12 (Arhgef12) and consequently activates RhoA/ROCK signaling. RhoA/ROCK pathway activator LPA can rescue the developmental deficits of Ogt deficient CGCs. Therefore, our study has revealed the critical function and related mechanisms of Ogt and O-GlcNAcylation in the cerebellum of adult male mice.SIGNIFICANCE STATEMENT Cerebellar function are regulated by diverse mechanisms. To unveil novel mechanisms is critical for understanding the cerebellar function and the clinical therapy of cerebellum-related diseases. In the present study, we have shown that O-GlcNAc transferase gene (Ogt) deletion induces abnormal cerebellar morphology, synaptic connection, and behavioral deficits of adult male mice. Mechanistically, Ogt catalyzes O-GlcNAcylation of Gα12, which promotes the binding to Arhgef12, and regulates RhoA/ROCK signaling pathway. Our study has uncovered the important roles of Ogt and O-GlcNAcylation in regulating cerebellar function and cerebellum-related behavior. Our results suggest that Ogt and O-GlcNAcylation could be potential targets for some cerebellum-related diseases.
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Affiliation(s)
- Jinyu Zhang
- The Children's Hospital, National Clinical Research Center for Child Health, School of Medicine, Zhejiang University, Hangzhou 310052, China
- The Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou 310029, China
| | - Kaiyan Wei
- The Children's Hospital, National Clinical Research Center for Child Health, School of Medicine, Zhejiang University, Hangzhou 310052, China
| | - Wenzheng Qu
- The Children's Hospital, National Clinical Research Center for Child Health, School of Medicine, Zhejiang University, Hangzhou 310052, China
| | - Mengxuan Wang
- The Children's Hospital, National Clinical Research Center for Child Health, School of Medicine, Zhejiang University, Hangzhou 310052, China
- The Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou 310029, China
| | - Qiang Zhu
- MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou 310058
- The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310002, China
| | - Xiaoxue Dong
- The Children's Hospital, National Clinical Research Center for Child Health, School of Medicine, Zhejiang University, Hangzhou 310052, China
- The Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou 310029, China
| | - Xiaoli Huang
- The Children's Hospital, National Clinical Research Center for Child Health, School of Medicine, Zhejiang University, Hangzhou 310052, China
| | - Wen Yi
- MOE Key Laboratory of Biosystems Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou 310058
- The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310002, China
| | - Shunliang Xu
- Department of Neurology, The Second Hospital, Cheeloo College of Medicine, Shandong University, Jinan 250033, China
| | - Xuekun Li
- The Children's Hospital, National Clinical Research Center for Child Health, School of Medicine, Zhejiang University, Hangzhou 310052, China
- The Institute of Translational Medicine, School of Medicine, Zhejiang University, Hangzhou 310029, China
- Key Laboratory of Diagnosis and Treatment of Neonatal Diseases of Zhejiang Province, Hangzhou 310052, China
- Binjiang Institute of Zhejiang University, Hangzhou 310053, China
- Zhejiang University Cancer Center, Zhejiang University, Hangzhou 310029, China
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7
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Duong P, Ramesh R, Schneider A, Won S, Cooper AJ, Svaren J. Modulation of Schwann cell homeostasis by the BAP1 deubiquitinase. Glia 2023; 71:1466-1480. [PMID: 36790040 PMCID: PMC10073320 DOI: 10.1002/glia.24351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 01/24/2023] [Accepted: 01/25/2023] [Indexed: 02/16/2023]
Abstract
Schwann cell programming during myelination involves transcriptional networks that activate gene expression but also repress genes that are active in neural crest/embryonic differentiation of Schwann cells. We previously found that a Schwann cell-specific deletion of the EED subunit of the Polycomb Repressive Complex (PRC2) led to inappropriate activation of many such genes. Moreover, some of these genes become re-activated in the pro-regenerative response of Schwann cells to nerve injury, and we found premature activation of the nerve injury program in a Schwann cell-specific knockout of Eed. Polycomb-associated histone modifications include H3K27 trimethylation formed by PRC2 and H2AK119 monoubiquitination (H2AK119ub1), deposited by Polycomb repressive complex 1 (PRC1). We recently found dynamic regulation of H2AK119ub1 in Schwann cell genes after injury. Therefore, we hypothesized that H2AK119 deubiquitination modulates the dynamic polycomb repression of genes involved in Schwann cell maturation. To determine the role of H2AK119 deubiquitination, we generated a Schwann cell-specific knockout of the H2AK119 deubiquitinase Bap1 (BRCA1-associated protein). We found that loss of Bap1 causes tomacula formation, decreased axon diameters and eventual loss of myelinated axons. The gene expression changes are accompanied by redistribution of H2AK119ub1 and H3K27me3 modifications to extragenic sites throughout the genome. BAP1 interacts with OGT in the PR-DUB complex, and our data suggest that the PR-DUB complex plays a multifunctional role in repression of the injury program. Overall, our results indicate Bap1 is required to restrict the spread of polycomb-associated histone modifications in Schwann cells and to promote myelin homeostasis in peripheral nerve.
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Affiliation(s)
- Phu Duong
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Cellular and Molecular Pathology Graduate Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Raghu Ramesh
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Comparative Biomedical Sciences Graduate Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Andrew Schneider
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Seongsik Won
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Aaron J Cooper
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - John Svaren
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Department Of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA
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8
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Wu HF, Huang CW, Art J, Liu HX, Hart GW, Zeltner N. O-GlcNAcylation is crucial for sympathetic neuron development, maintenance, functionality and contributes to peripheral neuropathy. Front Neurosci 2023; 17:1137847. [PMID: 37229433 PMCID: PMC10203903 DOI: 10.3389/fnins.2023.1137847] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 04/12/2023] [Indexed: 05/27/2023] Open
Abstract
O-GlcNAcylation is a post-translational modification (PTM) that regulates a wide range of cellular functions and has been associated with multiple metabolic diseases in various organs. The sympathetic nervous system (SNS) is the efferent portion of the autonomic nervous system that regulates metabolism of almost all organs in the body. How much the development and functionality of the SNS are influenced by O-GlcNAcylation, as well as how such regulation could contribute to sympathetic neuron (symN)-related neuropathy in diseased states, remains unknown. Here, we assessed the level of protein O-GlcNAcylation at various stages of symN development, using a human pluripotent stem cell (hPSC)-based symN differentiation paradigm. We found that pharmacological disruption of O-GlcNAcylation impaired both the growth and survival of hPSC-derived symNs. In the high glucose condition that mimics hyperglycemia, hPSC-derived symNs were hyperactive, and their regenerative capacity was impaired, which resembled typical neuronal defects in patients and animal models of diabetes mellitus. Using this model of sympathetic neuropathy, we discovered that O-GlcNAcylation increased in symNs under high glucose, which lead to hyperactivity. Pharmacological inhibition of O-GlcNAcylation rescued high glucose-induced symN hyperactivity and cell stress. This framework provides the first insight into the roles of O-GlcNAcylation in both healthy and diseased human symNs and may be used as a platform for therapeutic studies.
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Affiliation(s)
- Hsueh-Fu Wu
- Center for Molecular Medicine, University of Georgia, Athens, GA, United States
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - Chia-Wei Huang
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States
| | - Jennifer Art
- Center for Molecular Medicine, University of Georgia, Athens, GA, United States
- Biomedical and Translational Sciences Institute, Neuroscience Program, University of Georgia, Athens, GA, United States
| | - Hong-Xiang Liu
- Regenerative Bioscience Center, Department of Animal and Dairy Science, College of Agricultural and Environmental Sciences, University of Georgia, Athens, GA, United States
| | - Gerald W. Hart
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States
| | - Nadja Zeltner
- Center for Molecular Medicine, University of Georgia, Athens, GA, United States
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
- Department of Cellular Biology, University of Georgia, Athens, GA, United States
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9
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Cunningham ME, McGonigal R, Barrie JA, Campbell CI, Yao D, Willison HJ. Axolemmal nanoruptures arising from paranodal membrane injury induce secondary axon degeneration in murine Guillain-Barré syndrome. J Peripher Nerv Syst 2023; 28:17-31. [PMID: 36710500 PMCID: PMC10947354 DOI: 10.1111/jns.12532] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/19/2023] [Accepted: 01/23/2023] [Indexed: 01/31/2023]
Abstract
The major determinant of poor outcome in Guillain-Barré syndrome (GBS) is axonal degeneration. Pathways leading to primary axonal injury in the motor axonal variant are well established, whereas mechanisms of secondary axonal injury in acute inflammatory demyelinating polyneuropathy (AIDP) are unknown. We recently developed an autoantibody-and complement-mediated model of murine AIDP, in which prominent injury to glial membranes at the node of Ranvier results in severe disruption to paranodal components. Acutely, axonal integrity was maintained, but over time secondary axonal degeneration occurred. Herein, we describe the differential mechanisms underlying acute glial membrane injury and secondary axonal injury in this model. Ex vivo nerve-muscle explants were injured for either acute or extended periods with an autoantibody-and complement-mediated injury to glial paranodal membranes. This model was used to test several possible mechanisms of axon degeneration including calpain activation, and to monitor live axonal calcium signalling. Glial calpains induced acute disruption of paranodal membrane proteins in the absence of discernible axonal injury. Over time, we observed progressive axonal degeneration which was markedly attenuated by axon-specific calpain inhibition. Injury was unaffected by all other tested methods of protection. Trans-axolemmal diffusion of fluorescent proteins and live calcium imaging studies indirectly demonstrated the presence of nanoruptures in the axon membrane. This study outlines one mechanism by which secondary axonal degeneration arises in the AIDP variant of GBS where acute paranodal loop injury is prominent. The data also support the development of calpain inhibitors to attenuate both primary and secondary axonal degeneration in GBS.
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Affiliation(s)
| | - Rhona McGonigal
- School of Infection & ImmunityUniversity of GlasgowGlasgowUK
| | | | | | - Denggao Yao
- School of Infection & ImmunityUniversity of GlasgowGlasgowUK
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10
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Steyer AM, Buscham TJ, Lorenz C, Hümmert S, Eichel-Vogel MA, Schadt LC, Edgar JM, Köster S, Möbius W, Nave KA, Werner HB. Focused ion beam-scanning electron microscopy links pathological myelin outfoldings to axonal changes in mice lacking Plp1 or Mag. Glia 2023; 71:509-523. [PMID: 36354016 DOI: 10.1002/glia.24290] [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: 07/11/2022] [Revised: 10/10/2022] [Accepted: 10/17/2022] [Indexed: 11/11/2022]
Abstract
Healthy myelin sheaths consist of multiple compacted membrane layers closely encasing the underlying axon. The ultrastructure of CNS myelin requires specialized structural myelin proteins, including the transmembrane-tetraspan proteolipid protein (PLP) and the Ig-CAM myelin-associated glycoprotein (MAG). To better understand their functional relevance, we asked to what extent the axon/myelin-units display similar morphological changes if PLP or MAG are lacking. We thus used focused ion beam-scanning electron microscopy (FIB-SEM) to re-investigate axon/myelin-units side-by-side in Plp- and Mag-null mutant mice. By three-dimensional reconstruction and morphometric analyses, pathological myelin outfoldings extend up to 10 μm longitudinally along myelinated axons in both models. More than half of all assessed outfoldings emerge from internodal myelin. Unexpectedly, three-dimensional reconstructions demonstrated that both models displayed complex axonal pathology underneath the myelin outfoldings, including axonal sprouting. Axonal anastomosing was additionally observed in Plp-null mutant mice. Importantly, normal-appearing axon/myelin-units displayed significantly increased axonal diameters in both models according to quantitative assessment of electron micrographs. These results imply that healthy CNS myelin sheaths facilitate normal axonal diameters and shape, a function that is impaired when structural myelin proteins PLP or MAG are lacking.
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Affiliation(s)
- Anna M Steyer
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Electron Microscopy-City Campus, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Tobias J Buscham
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Charlotta Lorenz
- Institute for X-Ray Physics, University of Göttingen, Göttingen, Germany
| | - Sophie Hümmert
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Maria A Eichel-Vogel
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Leonie C Schadt
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Julia M Edgar
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Sarah Köster
- Institute for X-Ray Physics, University of Göttingen, Göttingen, Germany.,Cluster of Excellence 'Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells' (MBExC), University of Göttingen, Göttingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Electron Microscopy-City Campus, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.,Cluster of Excellence 'Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells' (MBExC), University of Göttingen, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
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11
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Dupas T, Betus C, Blangy-Letheule A, Pelé T, Persello A, Denis M, Lauzier B. An overview of tools to decipher O-GlcNAcylation from historical approaches to new insights. Int J Biochem Cell Biol 2022; 151:106289. [PMID: 36031106 DOI: 10.1016/j.biocel.2022.106289] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/21/2022] [Accepted: 08/23/2022] [Indexed: 11/19/2022]
Abstract
O-GlcNAcylation is a post-translational modification which affects approximately 5000 human proteins. Its involvement has been shown in many if not all biological processes. Variations in O-GlcNAcylation levels can be associated with the development of diseases. Deciphering the role of O-GlcNAcylation is an important issue to (i) understand its involvement in pathophysiological development and (ii) develop new therapeutic strategies to modulate O-GlcNAc levels. Over the past 30 years, despite the development of several approaches, knowledge of its role and regulation have remained limited. This review proposes an overview of the currently available tools to study O-GlcNAcylation and identify O-GlcNAcylated proteins. Briefly, we discuss pharmacological modulators, methods to study O-GlcNAcylation levels and approaches for O-GlcNAcylomic profiling. This review aims to contribute to a better understanding of the methods used to study O-GlcNAcylation and to promote efforts in the development of new strategies to explore this promising modification.
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Affiliation(s)
- Thomas Dupas
- Nantes Université, CHU Nantes, CNRS, INSERM, l'institut du thorax, F-44000 Nantes, France.
| | - Charlotte Betus
- Nantes Université, CHU Nantes, CNRS, INSERM, l'institut du thorax, F-44000 Nantes, France; Department of Pharmacology and Physiology, University of Montreal, Montreal, QC H3T 1C5, Canada; CHU Sainte-Justine Research Center, Montreal, QC H3T 1C5, Canada
| | | | - Thomas Pelé
- Nantes Université, CHU Nantes, CNRS, INSERM, l'institut du thorax, F-44000 Nantes, France
| | - Antoine Persello
- Nantes Université, CHU Nantes, CNRS, INSERM, l'institut du thorax, F-44000 Nantes, France
| | - Manon Denis
- Nantes Université, CHU Nantes, CNRS, INSERM, l'institut du thorax, F-44000 Nantes, France; Department of Pharmacology and Physiology, University of Montreal, Montreal, QC H3T 1C5, Canada; CHU Sainte-Justine Research Center, Montreal, QC H3T 1C5, Canada
| | - Benjamin Lauzier
- Nantes Université, CHU Nantes, CNRS, INSERM, l'institut du thorax, F-44000 Nantes, France
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12
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Tricaud N, Gautier B, Berthelot J, Gonzalez S, Van Hameren G. Traumatic and Diabetic Schwann Cell Demyelination Is Triggered by a Transient Mitochondrial Calcium Release through Voltage Dependent Anion Channel 1. Biomedicines 2022; 10:biomedicines10061447. [PMID: 35740468 PMCID: PMC9220872 DOI: 10.3390/biomedicines10061447] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 06/07/2022] [Accepted: 06/08/2022] [Indexed: 11/16/2022] Open
Abstract
A large number of peripheral neuropathies, among which are traumatic and diabetic peripheral neuropathies, result from the degeneration of the myelin sheath, a process called demyelination. Demyelination does not result from Schwann cell death but from Schwann cell dedifferentiation, which includes reprograming and several catabolic and anabolic events. Starting around 4 h after nerve injury, activation of MAPK/cJun pathways is the earliest characterized step of this dedifferentiation program. Here we show, using real-time in vivo imaging, that Schwann cell mitochondrial pH, motility and calcium content are altered as soon as one hour after nerve injury. Mitochondrial calcium release occurred through the VDAC outer membrane channel and mPTP inner membrane channel. This calcium influx in the cytoplasm induced Schwann-cell demyelination via MAPK/c-Jun activation. Blocking calcium release through VDAC silencing or VDAC inhibitor TRO19622 prevented demyelination. We found that the kinetics of mitochondrial calcium release upon nerve injury were altered in the Schwann cells of diabetic mice suggesting a permanent leak of mitochondrial calcium in the cytoplasm. TRO19622 treatment alleviated peripheral nerve defects and motor deficit in diabetic mice. Together, these data indicate that mitochondrial calcium homeostasis is instrumental in the Schwann cell demyelination program and that blocking VDAC constitutes a molecular basis for developing anti-demyelinating drugs for diabetic peripheral neuropathy.
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Affiliation(s)
- Nicolas Tricaud
- Institut des Neurosciences de Montpellier, Univ. Montpellier, INSERM, 34000 Montpellier, France; (B.G.); (J.B.); (S.G.); (G.V.H.)
- I-Stem, UEVE/UPS U861, INSERM U861, AFM, 91100 Corbeil-Essonnes, France
- Correspondence:
| | - Benoit Gautier
- Institut des Neurosciences de Montpellier, Univ. Montpellier, INSERM, 34000 Montpellier, France; (B.G.); (J.B.); (S.G.); (G.V.H.)
| | - Jade Berthelot
- Institut des Neurosciences de Montpellier, Univ. Montpellier, INSERM, 34000 Montpellier, France; (B.G.); (J.B.); (S.G.); (G.V.H.)
| | - Sergio Gonzalez
- Institut des Neurosciences de Montpellier, Univ. Montpellier, INSERM, 34000 Montpellier, France; (B.G.); (J.B.); (S.G.); (G.V.H.)
| | - Gerben Van Hameren
- Institut des Neurosciences de Montpellier, Univ. Montpellier, INSERM, 34000 Montpellier, France; (B.G.); (J.B.); (S.G.); (G.V.H.)
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13
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Yan B, Li W, Hackenberger CPR. A silyl ether-protected building block for O-GlcNAcylated peptide synthesis to enable one-pot acidic deprotection. Org Biomol Chem 2021; 19:8014-8017. [PMID: 34596198 DOI: 10.1039/d1ob00510c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this report, we introduce a novel building block for Fmoc/tBu solid phase peptide synthesis (SPPS) of β-linked O-GlcNAcylated peptides. This building block carries acid labile silyl ether protecting groups, which are fully removed under TFA-mediated peptide cleavage conditions from the resin, thus requiring fewer synthetic steps and no intermediate purification as compared to other acid or base labile protecting group strategies.
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Affiliation(s)
- Bingjia Yan
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany.
- Humboldt Universität zu Berlin, Institut für Chemie, Brook-Taylor-Str. 2, 12489 Berlin, Germany
| | - Wenyi Li
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany.
| | - Christian P R Hackenberger
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany.
- Humboldt Universität zu Berlin, Institut für Chemie, Brook-Taylor-Str. 2, 12489 Berlin, Germany
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14
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Della-Flora Nunes G, Wilson ER, Hurley E, He B, O'Malley BW, Poitelon Y, Wrabetz L, Feltri ML. Activation of mTORC1 and c-Jun by Prohibitin1 loss in Schwann cells may link mitochondrial dysfunction to demyelination. eLife 2021; 10:e66278. [PMID: 34519641 PMCID: PMC8478418 DOI: 10.7554/elife.66278] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 09/13/2021] [Indexed: 12/26/2022] Open
Abstract
Schwann cell (SC) mitochondria are quickly emerging as an important regulator of myelin maintenance in the peripheral nervous system (PNS). However, the mechanisms underlying demyelination in the context of mitochondrial dysfunction in the PNS are incompletely understood. We recently showed that conditional ablation of the mitochondrial protein Prohibitin 1 (PHB1) in SCs causes a severe and fast progressing demyelinating peripheral neuropathy in mice, but the mechanism that causes failure of myelin maintenance remained unknown. Here, we report that mTORC1 and c-Jun are continuously activated in the absence of Phb1, likely as part of the SC response to mitochondrial damage. Moreover, we demonstrate that these pathways are involved in the demyelination process, and that inhibition of mTORC1 using rapamycin partially rescues the demyelinating pathology. Therefore, we propose that mTORC1 and c-Jun may play a critical role as executioners of demyelination in the context of perturbations to SC mitochondria.
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Affiliation(s)
- Gustavo Della-Flora Nunes
- Hunter James Kelly Research Institute, University at BuffaloBuffaloUnited States
- Department of Biochemistry, University at BuffaloBuffaloUnited States
| | - Emma R Wilson
- Hunter James Kelly Research Institute, University at BuffaloBuffaloUnited States
- Department of Biochemistry, University at BuffaloBuffaloUnited States
| | - Edward Hurley
- Hunter James Kelly Research Institute, University at BuffaloBuffaloUnited States
| | - Bin He
- Immunobiology & Transplant Science Center and Department of Surgery, Houston Methodist HospitalHoustonUnited States
| | - Bert W O'Malley
- Department of Medicine and Molecular and Cellular Biology, Baylor College of MedicineHoustonUnited States
| | - Yannick Poitelon
- Department of Neuroscience and Experimental Therapeutics, Albany Medical CollegeAlbanyUnited States
| | - Lawrence Wrabetz
- Hunter James Kelly Research Institute, University at BuffaloBuffaloUnited States
- Department of Biochemistry, University at BuffaloBuffaloUnited States
- Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at BuffaloBuffaloUnited States
| | - M Laura Feltri
- Hunter James Kelly Research Institute, University at BuffaloBuffaloUnited States
- Department of Biochemistry, University at BuffaloBuffaloUnited States
- Department of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at BuffaloBuffaloUnited States
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15
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Wrestling and Wrapping: A Perspective on SUMO Proteins in Schwann Cells. Biomolecules 2021; 11:biom11071055. [PMID: 34356679 PMCID: PMC8301837 DOI: 10.3390/biom11071055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/12/2021] [Accepted: 07/13/2021] [Indexed: 11/20/2022] Open
Abstract
Schwann cell development and peripheral nerve myelination are finely orchestrated multistep processes; some of the underlying mechanisms are well described and others remain unknown. Many posttranslational modifications (PTMs) like phosphorylation and ubiquitination have been reported to play a role during the normal development of the peripheral nervous system (PNS) and in demyelinating neuropathies. However, a relatively novel PTM, SUMOylation, has not been studied in these contexts. SUMOylation involves the covalent attachment of one or more small ubiquitin-like modifier (SUMO) proteins to a substrate, which affects the function, cellular localization, and further PTMs of the conjugated protein. SUMOylation also regulates other proteins indirectly by facilitating non-covalent protein–protein interaction via SUMO interaction motifs (SIM). This pathway has important consequences on diverse cellular processes, and dysregulation of this pathway has been reported in several diseases including neurological and degenerative conditions. In this article, we revise the scarce literature on SUMOylation in Schwann cells and the PNS, we propose putative substrate proteins, and we speculate on potential mechanisms underlying the possible involvement of this PTM in peripheral myelination and neuropathies.
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16
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Maynard JC, Chalkley RJ. Methods for Enrichment and Assignment of N-Acetylglucosamine Modification Sites. Mol Cell Proteomics 2021; 20:100031. [PMID: 32938750 PMCID: PMC8724609 DOI: 10.1074/mcp.r120.002206] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/27/2020] [Accepted: 09/16/2020] [Indexed: 12/21/2022] Open
Abstract
O-GlcNAcylation, the addition of a single N-acetylglucosamine residue to serine and threonine residues of cytoplasmic, nuclear, or mitochondrial proteins, is a widespread regulatory posttranslational modification. It is involved in the response to nutritional status and stress, and its dysregulation is associated with diseases ranging from Alzheimer's to diabetes. Although the modification was first detected over 35 years ago, research into the function of O-GlcNAcylation has accelerated dramatically in the last 10 years owing to the development of new enrichment and mass spectrometry techniques that facilitate its analysis. This article summarizes methods for O-GlcNAc enrichment, key mass spectrometry instrumentation advancements, particularly those that allow modification site localization, and software tools that allow analysis of data from O-GlcNAc-modified peptides.
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Affiliation(s)
- Jason C Maynard
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA, USA
| | - Robert J Chalkley
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA, USA.
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17
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Xu S, Sun F, Tong M, Wu R. MS-based proteomics for comprehensive investigation of protein O-GlcNAcylation. Mol Omics 2021; 17:186-196. [PMID: 33687411 DOI: 10.1039/d1mo00025j] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Protein O-GlcNAcylation refers to the covalent binding of a single N-acetylglucosamine (GlcNAc) to the serine or threonine residue. This modification primarily occurs on proteins in the nucleus and the cytosol, and plays critical roles in many cellular events, including regulation of gene expression and signal transduction. Aberrant protein O-GlcNAcylation is directly related to human diseases such as cancers, diabetes and neurodegenerative diseases. In the past decades, considerable progress has been made for global and site-specific analysis of O-GlcNAcylation in complex biological samples using mass spectrometry (MS)-based proteomics. In this review, we summarized previous efforts on comprehensive investigation of protein O-GlcNAcylation by MS. Specifically, the review is focused on methods for enriching and site-specifically mapping O-GlcNAcylated peptides, and applications for quantifying protein O-GlcNAcylation in different biological systems. As O-GlcNAcylation is an important protein modification for cell survival, effective methods are essential for advancing our understanding of glycoprotein functions and cellular events.
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Affiliation(s)
- Senhan Xu
- School of Chemistry and Biochemistry and the Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
| | - Fangxu Sun
- School of Chemistry and Biochemistry and the Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
| | - Ming Tong
- School of Chemistry and Biochemistry and the Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
| | - Ronghu Wu
- School of Chemistry and Biochemistry and the Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
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18
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Muppirala AN, Limbach LE, Bradford EF, Petersen SC. Schwann cell development: From neural crest to myelin sheath. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2020; 10:e398. [PMID: 33145925 DOI: 10.1002/wdev.398] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 10/06/2020] [Accepted: 10/07/2020] [Indexed: 12/16/2022]
Abstract
Vertebrate nervous system function requires glial cells, including myelinating glia that insulate axons and provide trophic support that allows for efficient signal propagation by neurons. In vertebrate peripheral nervous systems, neural crest-derived glial cells known as Schwann cells (SCs) generate myelin by encompassing and iteratively wrapping membrane around single axon segments. SC gliogenesis and neurogenesis are intimately linked and governed by a complex molecular environment that shapes their developmental trajectory. Changes in this external milieu drive developing SCs through a series of distinct morphological and transcriptional stages from the neural crest to a variety of glial derivatives, including the myelinating sublineage. Cues originate from the extracellular matrix, adjacent axons, and the developing SC basal lamina to trigger intracellular signaling cascades and gene expression changes that specify stages and transitions in SC development. Here, we integrate the findings from in vitro neuron-glia co-culture experiments with in vivo studies investigating SC development, particularly in zebrafish and mouse, to highlight critical factors that specify SC fate. Ultimately, we connect classic biochemical and mutant studies with modern genetic and visualization tools that have elucidated the dynamics of SC development. This article is categorized under: Signaling Pathways > Cell Fate Signaling Nervous System Development > Vertebrates: Regional Development.
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Affiliation(s)
- Anoohya N Muppirala
- Program in Neuroscience, Harvard Medical School, Boston, Massachusetts, USA.,Department of Neuroscience, Kenyon College, Gambier, Ohio, USA
| | | | | | - Sarah C Petersen
- Department of Neuroscience, Kenyon College, Gambier, Ohio, USA.,Department of Biology, Kenyon College, Gambier, Ohio, USA
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19
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De Micheli AJ, Swanson JB, Disser NP, Martinez LM, Walker NR, Oliver DJ, Cosgrove BD, Mendias CL. Single-cell transcriptomic analysis identifies extensive heterogeneity in the cellular composition of mouse Achilles tendons. Am J Physiol Cell Physiol 2020; 319:C885-C894. [PMID: 32877217 DOI: 10.1152/ajpcell.00372.2020] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Tendon is a dense connective tissue that stores and transmits forces between muscles and bones. Cellular heterogeneity is increasingly recognized as an important factor in the biological basis of tissue homeostasis and disease, yet little is known about the diversity of cell types that populate tendon. To address this, we determined the heterogeneity of cell populations within mouse Achilles tendons using single-cell RNA sequencing. In assembling a transcriptomic atlas of Achilles tendons, we identified 11 distinct types of cells, including three previously undescribed populations of tendon fibroblasts. Prior studies have indicated that pericytes, which are found in the vasculature of tendons, could serve as a potential source of progenitor cells for adult tendon fibroblasts. Using trajectory inference analysis, we provide additional support for the notion that pericytes are likely to be at least one of the progenitor cell populations for the fibroblasts that compose adult tendons. We also modeled cell-cell interactions and identified previously undescribed ligand-receptor signaling interactions involved in tendon homeostasis. Our novel and interactive tendon atlas highlights previously underappreciated heterogeneity between and within tendon cell populations. The atlas also serves as a resource to further the understanding of tendon extracellular matrix assembly and maintenance and in the design of therapies for tendinopathies.
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Affiliation(s)
- Andrea J De Micheli
- Hospital for Special Surgery, New York, New York.,Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York
| | | | | | | | - Nicholas R Walker
- Hospital for Special Surgery, New York, New York.,Department of Physiology and Biophysics, Weill Cornell Medical College, New York, New York
| | | | - Benjamin D Cosgrove
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York
| | - Christopher L Mendias
- Hospital for Special Surgery, New York, New York.,Department of Physiology and Biophysics, Weill Cornell Medical College, New York, New York
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20
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Age-related loss of neural stem cell O-GlcNAc promotes a glial fate switch through STAT3 activation. Proc Natl Acad Sci U S A 2020; 117:22214-22224. [PMID: 32848054 PMCID: PMC7486730 DOI: 10.1073/pnas.2007439117] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Depletion of the neural stem cell (NSC) pool is a major driver of age-related regenerative decline in the hippocampus. While increased quiescence is a major contributor to this decline, NSCs can also undergo terminal differentiation into astrocytes, thus restricting the stem cell pool. The mechanisms underlying this fate switch and their relation to age-related regenerative decline have not yet been fully elucidated. In this study, we report an age-related decline in NSC O-GlcNAcylation, coincident with reduced neurogenesis and increased gliogenesis. We identify loss of O-GlcNAcylation at STAT3 T717 in the hippocampus with age, and demonstrate that O-GlcNAcylation of this site is a critical determinant of NSC fate. Our work expands our understanding of how posttranslational modifications influence the aging brain. Increased neural stem cell (NSC) quiescence is a major determinant of age-related regenerative decline in the adult hippocampus. However, a coextensive model has been proposed in which division-coupled conversion of NSCs into differentiated astrocytes restrict the stem cell pool with age. Here we report that age-related loss of the posttranslational modification, O-linked β-N-acetylglucosamine (O-GlcNAc), in NSCs promotes a glial fate switch. We detect an age-dependent decrease in NSC O-GlcNAc levels coincident with decreased neurogenesis and increased gliogenesis in the mature hippocampus. Mimicking an age-related loss of NSC O-GlcNAcylation in young mice reduces neurogenesis, increases astrocyte differentiation, and impairs associated cognitive function. Using RNA-sequencing of primary NSCs following decreased O-GlcNAcylation, we detected changes in the STAT3 signaling pathway indicative of glial differentiation. Moreover, using O-GlcNAc–specific mass spectrometry analysis of the aging hippocampus, together with an in vitro site-directed mutagenesis approach, we identify loss of STAT3 O-GlcNAc at Threonine 717 as a driver of astrocyte differentiation. Our data identify the posttranslational modification, O-GlcNAc, as a key molecular regulator of regenerative decline underlying an age-related NSC fate switch.
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21
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Maynard JC, Fujihira H, Dolgonos GE, Suzuki T, Burlingame AL. Cytosolic N-GlcNAc proteins are formed by the action of endo-β-N-acetylglucosaminidase. Biochem Biophys Res Commun 2020; 530:719-724. [PMID: 32782141 DOI: 10.1016/j.bbrc.2020.06.127] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 06/24/2020] [Indexed: 01/27/2023]
Abstract
NGLY1 is a widely conserved eukaryotic cytosolic deglycosylating enzyme involved in the endoplasmic reticulum-associated degradation (ERAD) process, which eliminates misfolded proteins through retrograde translocation and proteasomal degradation. A human genetic disorder called NGLY1-deficiency has been reported, indicating the functional importance of NGLY1 in humans. Evidence suggests that Ngly1-KO is embryonic lethal in mice, while additional deletion of the Engase gene, encoding another cytosolic deglycosylating enzyme (endo-β-N-acetylglucosaminidase; ENGase), partially rescued lethality. Upon compromised Ngly1 activity, ENGase-mediated deglycosylation of misfolded glycoproteins may cause excess formation of N-GlcNAc proteins in the cytosol, leading to detrimental effects in the mice. Whether endogenous N-GlcNAc proteins are really formed in Ngly1-KO cells/animals or not remains unclarified. Here, comprehensive identification of O- and N-GlcNAc proteins was carried out using purified cytosol from wild type, Ngly1-KO, Engase-KO, and Ngly1/Engase double KO mouse embryonic fibroblasts. It was revealed that while there is no dramatic change in the level of O-GlcNAc proteins among cells examined, there was a vast increase of N-GlcNAc proteins in Ngly1-KO cells upon proteasome inhibition. Importantly, few N-GlcNAc proteins were observed in Engase-KO or Ngly1/Engase double-KO cells, clearly indicating that the cytosolic ENGase is responsible for the formation of N-GlcNAc proteins. The excess formation of N-GlcNAc proteins may at least in part account for the pathogenesis of NGLY1-deficiency.
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Affiliation(s)
- Jason C Maynard
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA 94158, USA
| | - Haruhiko Fujihira
- Division of Glycobiologics, Intractable Disease Research Center, Juntendo University Graduate School of Medicine, Tokyo, Japan; Glycometabolic Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Saitama, Japan
| | - Gabby E Dolgonos
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA 94158, USA
| | - Tadashi Suzuki
- Glycometabolic Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Saitama, Japan; Suzuki Project, T-CiRA Discovery, Kanagawa, Japan.
| | - Alma L Burlingame
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA 94158, USA
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22
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Poitelon Y, Kopec AM, Belin S. Myelin Fat Facts: An Overview of Lipids and Fatty Acid Metabolism. Cells 2020; 9:cells9040812. [PMID: 32230947 PMCID: PMC7226731 DOI: 10.3390/cells9040812] [Citation(s) in RCA: 148] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 03/24/2020] [Accepted: 03/25/2020] [Indexed: 12/11/2022] Open
Abstract
Myelin is critical for the proper function of the nervous system and one of the most complex cell–cell interactions of the body. Myelination allows for the rapid conduction of action potentials along axonal fibers and provides physical and trophic support to neurons. Myelin contains a high content of lipids, and the formation of the myelin sheath requires high levels of fatty acid and lipid synthesis, together with uptake of extracellular fatty acids. Recent studies have further advanced our understanding of the metabolism and functions of myelin fatty acids and lipids. In this review, we present an overview of the basic biology of myelin lipids and recent insights on the regulation of fatty acid metabolism and functions in myelinating cells. In addition, this review may serve to provide a foundation for future research characterizing the role of fatty acids and lipids in myelin biology and metabolic disorders affecting the central and peripheral nervous system.
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23
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Otani Y, Ohno N, Cui J, Yamaguchi Y, Baba H. Upregulation of large myelin protein zero leads to Charcot-Marie-Tooth disease-like neuropathy in mice. Commun Biol 2020; 3:121. [PMID: 32170207 PMCID: PMC7070019 DOI: 10.1038/s42003-020-0854-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Accepted: 02/24/2020] [Indexed: 01/01/2023] Open
Abstract
Charcot-Marie-Tooth (CMT) disease is a hereditary neuropathy mainly caused by gene mutation of peripheral myelin proteins including myelin protein zero (P0, MPZ). Large myelin protein zero (L-MPZ) is an isoform of P0 that contains an extended polypeptide synthesized by translational readthrough at the C-terminus in tetrapods, including humans. The physiological role of L-MPZ and consequences of an altered L-MPZ/P0 ratio in peripheral myelin are not known. To clarify this, we used genome editing to generate a mouse line (L-MPZ mice) that produced L-MPZ instead of P0. Motor tests and electrophysiological, immunohistological, and electron microscopy analyses show that homozygous L-MPZ mice exhibit CMT-like phenotypes including thin and/or loose myelin, increased small-caliber axons, and disorganized axo-glial interactions. Heterozygous mice show a milder phenotype. These results highlight the importance of an appropriate L-MPZ/P0 ratio and show that aberrant readthrough of a myelin protein causes neuropathy.
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Affiliation(s)
- Yoshinori Otani
- Department of Molecular Neurobiology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Japan
| | - Nobuhiko Ohno
- Department of Anatomy, Division of Histology and Cell Biology, School of Medicine, Jichi Medical University, Shimotsuke, Japan
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki, Japan
| | - Jingjing Cui
- Department of Molecular Neurobiology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Japan
| | - Yoshihide Yamaguchi
- Department of Molecular Neurobiology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Japan.
| | - Hiroko Baba
- Department of Molecular Neurobiology, Tokyo University of Pharmacy and Life Sciences, Hachioji, Japan
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24
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Siems SB, Jahn O, Eichel MA, Kannaiyan N, Wu LMN, Sherman DL, Kusch K, Hesse D, Jung RB, Fledrich R, Sereda MW, Rossner MJ, Brophy PJ, Werner HB. Proteome profile of peripheral myelin in healthy mice and in a neuropathy model. eLife 2020; 9:e51406. [PMID: 32130108 PMCID: PMC7056269 DOI: 10.7554/elife.51406] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 02/19/2020] [Indexed: 02/07/2023] Open
Abstract
Proteome and transcriptome analyses aim at comprehending the molecular profiles of the brain, its cell-types and subcellular compartments including myelin. Despite the relevance of the peripheral nervous system for normal sensory and motor capabilities, analogous approaches to peripheral nerves and peripheral myelin have fallen behind evolving technical standards. Here we assess the peripheral myelin proteome by gel-free, label-free mass-spectrometry for deep quantitative coverage. Integration with RNA-Sequencing-based developmental mRNA-abundance profiles and neuropathy disease genes illustrates the utility of this resource. Notably, the periaxin-deficient mouse model of the neuropathy Charcot-Marie-Tooth 4F displays a highly pathological myelin proteome profile, exemplified by the discovery of reduced levels of the monocarboxylate transporter MCT1/SLC16A1 as a novel facet of the neuropathology. This work provides the most comprehensive proteome resource thus far to approach development, function and pathology of peripheral myelin, and a straightforward, accurate and sensitive workflow to address myelin diversity in health and disease.
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Affiliation(s)
- Sophie B Siems
- Department of Neurogenetics, Max Planck Institute of Experimental MedicineGöttingenGermany
| | - Olaf Jahn
- Proteomics Group, Max Planck Institute of Experimental MedicineGöttingenGermany
| | - Maria A Eichel
- Department of Neurogenetics, Max Planck Institute of Experimental MedicineGöttingenGermany
| | - Nirmal Kannaiyan
- Department of Psychiatry and Psychotherapy, University Hospital, LMU MunichMunichGermany
| | - Lai Man N Wu
- Centre for Discovery Brain Sciences, University of EdinburghEdinburghUnited Kingdom
| | - Diane L Sherman
- Centre for Discovery Brain Sciences, University of EdinburghEdinburghUnited Kingdom
| | - Kathrin Kusch
- Department of Neurogenetics, Max Planck Institute of Experimental MedicineGöttingenGermany
| | - Dörte Hesse
- Proteomics Group, Max Planck Institute of Experimental MedicineGöttingenGermany
| | - Ramona B Jung
- Department of Neurogenetics, Max Planck Institute of Experimental MedicineGöttingenGermany
| | - Robert Fledrich
- Department of Neurogenetics, Max Planck Institute of Experimental MedicineGöttingenGermany
- Institute of Anatomy, University of LeipzigLeipzigGermany
| | - Michael W Sereda
- Department of Neurogenetics, Max Planck Institute of Experimental MedicineGöttingenGermany
- Department of Clinical Neurophysiology, University Medical CenterGöttingenGermany
| | - Moritz J Rossner
- Department of Psychiatry and Psychotherapy, University Hospital, LMU MunichMunichGermany
| | - Peter J Brophy
- Centre for Discovery Brain Sciences, University of EdinburghEdinburghUnited Kingdom
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental MedicineGöttingenGermany
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25
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Raasakka A, Kursula P. Flexible Players within the Sheaths: The Intrinsically Disordered Proteins of Myelin in Health and Disease. Cells 2020; 9:cells9020470. [PMID: 32085570 PMCID: PMC7072810 DOI: 10.3390/cells9020470] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 02/16/2020] [Accepted: 02/16/2020] [Indexed: 02/07/2023] Open
Abstract
Myelin ensheathes selected axonal segments within the nervous system, resulting primarily in nerve impulse acceleration, as well as mechanical and trophic support for neurons. In the central and peripheral nervous systems, various proteins that contribute to the formation and stability of myelin are present, which also harbor pathophysiological roles in myelin disease. Many myelin proteins have common attributes, including small size, hydrophobic segments, multifunctionality, longevity, and regions of intrinsic disorder. With recent advances in protein biophysical characterization and bioinformatics, it has become evident that intrinsically disordered proteins (IDPs) are abundant in myelin, and their flexible nature enables multifunctionality. Here, we review known myelin IDPs, their conservation, molecular characteristics and functions, and their disease relevance, along with open questions and speculations. We place emphasis on classifying the molecular details of IDPs in myelin, and we correlate these with their various functions, including susceptibility to post-translational modifications, function in protein–protein and protein–membrane interactions, as well as their role as extended entropic chains. We discuss how myelin pathology can relate to IDPs and which molecular factors are potentially involved.
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Affiliation(s)
- Arne Raasakka
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, NO-5009 Bergen, Norway;
| | - Petri Kursula
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, NO-5009 Bergen, Norway;
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Aapistie 7A, FI-90220 Oulu, Finland
- Correspondence:
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26
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Chen YH, Zhang H, Meng LB, Tang XY, Gong T, Yin J. Novel mutation in the periaxin gene causal to Charcot-Marie-Tooth disease type 4F. J Int Med Res 2020; 48:300060519862064. [PMID: 31426691 PMCID: PMC7581982 DOI: 10.1177/0300060519862064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Charcot–Marie–Tooth (CMT) disease is the most common hereditary neuropathy. Mutations in the periaxin gene (PRX) can cause CMT type 4F, an autosomal recessive neuropathy, which is clinically characterized by slowly progressive distal muscle atrophy and weakness, with pes cavus deformity of the foot, and the absence of deep tendon reflexes. To date, dozens of reports of PRX mutations have been published worldwide, but none have been reported in Chinese patients. Here, we describe a 14-year-old Chinese boy with neuropathy characterized by slowly progressive limb weakness and atrophy, as well as sensory ataxia, whose cerebrospinal protein levels were 1627 mg/L. Genetic analysis identified a novel homozygous mutation, c.1174C>T (p.R392X), in exon 6 of PRX, which is the first case of its kind recorded in China.
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Affiliation(s)
- Yu-Hui Chen
- Neurology Department, Beijing Hospital, National Center of Gerontology, Beijing 100730, P. R. China
| | - Hua Zhang
- Neurology Department, Beijing Hospital, National Center of Gerontology, Beijing 100730, P. R. China
| | - Ling-Bing Meng
- Neurology Department, Beijing Hospital, National Center of Gerontology, Beijing 100730, P. R. China
| | - Xiao-Yan Tang
- Clinical Laboratory of Zhongke, Beijing 102200, P. R. China
| | - Tao Gong
- Neurology Department, Beijing Hospital, National Center of Gerontology, Beijing 100730, P. R. China
| | - Jian Yin
- Neurology Department, Beijing Hospital, National Center of Gerontology, Beijing 100730, P. R. China
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27
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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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28
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Shepard CJ, Cline SG, Hinds D, Jahanbakhsh S, Prokop JW. Breakdown of multiple sclerosis genetics to identify an integrated disease network and potential variant mechanisms. Physiol Genomics 2019; 51:562-577. [PMID: 31482761 DOI: 10.1152/physiolgenomics.00120.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Genetics of multiple sclerosis (MS) are highly polygenic with few insights into mechanistic associations with pathology. In this study, we assessed MS genetics through linkage disequilibrium and missense variant interpretation to yield a MS gene network. This network of 96 genes was taken through pathway analysis, tissue expression profiles, single cell expression segregation, expression quantitative trait loci (eQTLs), genome annotations, transcription factor (TF) binding profiles, structural genome looping, and overlap with additional associated genetic traits. This work revealed immune system dysfunction, nerve cell myelination, energetic control, transcriptional regulation, and variants that overlap multiple autoimmune disorders. Tissue-specific expression and eQTLs of MS genes implicate multiple immune cell types including macrophages, neutrophils, and T cells, while the genes in neural cell types enrich for oligodendrocyte and myelin sheath biology. There are eQTLs in linkage with lead MS variants in 25 genes including the multitissue eQTL, rs9271640, for HLA-DRB1/DRB5. Using multiple functional genomic databases, we identified noncoding variants that disrupt TF binding for GABPA, CTCF, EGR1, YY1, SPI1, CLOCK, ARNTL, BACH1, and GFI1. Overall, this paper suggests multiple genetic mechanisms for MS associated variants while highlighting the importance of a systems biology and network approach when elucidating intersections of the immune and nervous system.
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Affiliation(s)
- C Joy Shepard
- Department of Biology, Athens State University, Athens, Alabama.,Graduate Biomedical Sciences, University of Alabama at Birmingham, Birmingham, Alabama
| | - Sara G Cline
- Department of Biology, Athens State University, Athens, Alabama
| | - David Hinds
- HudsonAlpha Institute for Biotechnology, Huntsville, Alabama.,Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, Michigan
| | - Seyedehameneh Jahanbakhsh
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, Michigan
| | - Jeremy W Prokop
- Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, Grand Rapids, Michigan.,Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan
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29
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Comprehensive Proteomic Analysis Reveals Intermediate Stage of Non-Lesional Psoriatic Skin and Points out the Importance of Proteins Outside this Trend. Sci Rep 2019; 9:11382. [PMID: 31388062 PMCID: PMC6684579 DOI: 10.1038/s41598-019-47774-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 06/28/2019] [Indexed: 11/15/2022] Open
Abstract
To better understand the pathomechanism of psoriasis, a comparative proteomic analysis was performed with non-lesional and lesional skin from psoriasis patients and skin from healthy individuals. Strikingly, 79.9% of the proteins that were differentially expressed in lesional and healthy skin exhibited expression levels in non-lesional skin that were within twofold of the levels observed in healthy and lesional skin, suggesting that non-lesional skin represents an intermediate stage. Proteins outside this trend were categorized into three groups: I. proteins in non-lesional skin exhibiting expression similar to lesional skin, which might be predisposing factors (i.e., CSE1L, GART, MYO18A and UGDH); II. proteins that were differentially expressed in non-lesional and lesional skin but not in healthy and lesional skin, which might be non-lesional characteristic alteration (i.e., CHCHD6, CHMP5, FLOT2, ITGA7, LEMD2, NOP56, PLVAP and RRAS); and III. proteins with contrasting differential expression in non-lesional and lesional skin compared to healthy skin, which might contribute to maintaining the non-lesional state (i.e., ITGA7, ITGA8, PLVAP, PSAPL1, SMARCA5 and XP32). Finally, proteins differentially expressed in lesions may indicate increased sensitivity to stimuli, peripheral nervous system alterations, furthermore MYBBP1A and PRKDC were identified as potential regulators of key pathomechanisms, including stress and immune response, proliferation and differentiation.
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30
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Schoor C, Brocke-Ahmadinejad N, Gieselmann V, Winter D. Investigation of Oligodendrocyte Precursor Cell Differentiation by Quantitative Proteomics. Proteomics 2019; 19:e1900057. [PMID: 31216117 DOI: 10.1002/pmic.201900057] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 06/02/2019] [Indexed: 01/20/2023]
Abstract
Oligodendrocytes, the myelinating cells of the central nervous system, are essential for correct brain function. They originate from oligodendrocyte precursor cells through a differentiation process which is only incompletely understood and impaired in a variety of demyelinating diseases. Better knowledge of this differentiation holds the promise to develop novel therapies for these disorders. The differentiation of rat oligodendrocyte precursor cells to oligodendrocytes in vitro is investigated. After confirmation of differentiation by immunohistochemical analysis using cell type-specific marker proteins, a quantitative proteomics study using tandem mass tags (TMT) is conducted. Four time points of differentiation covering early, intermediate, and late stages are investigated. Data analysis by Mascot and MaxQuant identified 5259 protein groups of which 471 are not described in the context of cells of the oligodendroglial lineage before. Quantitative analysis of the dataset revealed distinct regulation patterns for proteins of different functional categories including metabolic processes, regulation of the cell cycle, and transcriptional control of protein expression. The present data confirm a significant number of proteins known to play a role in oligodendrocytes and myelination. Furthermore, novel candidate proteins are identified which may play an important role in this differentiation process providing a valuable resource for oligodendrocyte research.
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Affiliation(s)
- Carmen Schoor
- Institute for Biochemistry and Molecular Biology, University of Bonn, 53115, Bonn, Germany
| | | | - Volkmar Gieselmann
- Institute for Biochemistry and Molecular Biology, University of Bonn, 53115, Bonn, Germany
| | - Dominic Winter
- Institute for Biochemistry and Molecular Biology, University of Bonn, 53115, Bonn, Germany
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31
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Alteration of O-GlcNAcylation affects assembly and axonal transport of neurofilament via phosphorylation. Neurosci Lett 2019; 698:97-104. [PMID: 30395884 DOI: 10.1016/j.neulet.2018.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 08/26/2018] [Accepted: 11/01/2018] [Indexed: 01/03/2023]
Abstract
Neurofilaments (NFs), the most abundant cytoskeletal components in the mature neuron, are hyperphosphorylated and accumulated in the neuronal cell body of AD brain, and the abnormalities of NFs appear to contribute to neurodegeneration. Although previous studies have showed that O-GlcNAcylation and phosphorylation of NFs regulate each other reciprocally, the NFs O-GlcNAcylation and its effects on assembly and axonal transport are poorly explored. Here, we focus on the role of dysregulation of O-GlcNAcylation on structure and function of neurofilaments by corresponding phosphorylation. In the study, we found that decreased O-GlcNAcylation by intracerebroventricular administration of Alloxan, 6-diazo-5-oxonorleucine (Don) and okadaic acid (OA) in the rats resulted in increased phosphorylation with assembly of lower and shorter NFs. In contrast, in the sample of NAG-thiazoline (NAG-Ae) causing increased O-GlcNAcylation, NFs showed elongated filaments fibers and higher proportion of assembly. Furthermore, alloxan treatment induced abnormal accumulation of NFs bodies and delayed time of Fluorescence Recovery After Photobleaching (FRAP) in SK-N-SH cells, but the NAG-Ae treatment speeded up the axonal transport. Our experiments suggest that increased O-GlcNAcylation plays a key role in protecting the structure and function of NFs including filament assembly and axonal transport via decreased phosphorylation. These results expanded the function of O-GlcNAcylation in AD pathogenesis.
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32
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Raasakka A, Linxweiler H, Brophy PJ, Sherman DL, Kursula P. Direct Binding of the Flexible C-Terminal Segment of Periaxin to β4 Integrin Suggests a Molecular Basis for CMT4F. Front Mol Neurosci 2019; 12:84. [PMID: 31024253 PMCID: PMC6465933 DOI: 10.3389/fnmol.2019.00084] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 03/19/2019] [Indexed: 11/13/2022] Open
Abstract
The process of myelination in the nervous system requires a coordinated formation of both transient and stable supramolecular complexes. Myelin-specific proteins play key roles in these assemblies, which may link membranes to each other or connect the myelinating cell cytoskeleton to the extracellular matrix. The myelin protein periaxin is known to play an important role in linking the Schwann cell cytoskeleton to the basal lamina through membrane receptors, such as the dystroglycan complex. Mutations that truncate periaxin from the C terminus cause demyelinating peripheral neuropathy, Charcot-Marie-Tooth (CMT) disease type 4F, indicating a function for the periaxin C-terminal region in myelination. We identified the cytoplasmic domain of β4 integrin as a specific high-affinity binding partner for periaxin. The C-terminal region of periaxin remains unfolded and flexible when bound to the third fibronectin type III domain of β4 integrin. Our data suggest that periaxin is able to link the Schwann cell cytoplasm to the basal lamina through a two-pronged interaction via different membrane protein complexes, which bind close to the N and C terminus of this elongated, flexible molecule.
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Affiliation(s)
- Arne Raasakka
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | | | - Peter J. Brophy
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Diane L. Sherman
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Petri Kursula
- Department of Biomedicine, University of Bergen, Bergen, Norway
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
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33
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Zachara NE. Critical observations that shaped our understanding of the function(s) of intracellular glycosylation (O-GlcNAc). FEBS Lett 2018; 592:3950-3975. [PMID: 30414174 DOI: 10.1002/1873-3468.13286] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 10/30/2018] [Accepted: 10/31/2018] [Indexed: 12/30/2022]
Abstract
Almost 100 years after the first descriptions of proteins conjugated to carbohydrates (mucins), several studies suggested that glycoproteins were not restricted to the serum, extracellular matrix, cell surface, or endomembrane system. In the 1980s, key data emerged demonstrating that intracellular proteins were modified by monosaccharides of O-linked β-N-acetylglucosamine (O-GlcNAc). Subsequently, this modification was identified on thousands of proteins that regulate cellular processes as diverse as protein aggregation, localization, post-translational modifications, activity, and interactions. In this Review, we will highlight critical discoveries that shaped our understanding of the molecular events underpinning the impact of O-GlcNAc on protein function, the role that O-GlcNAc plays in maintaining cellular homeostasis, and our understanding of the mechanisms that regulate O-GlcNAc-cycling.
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Affiliation(s)
- Natasha E Zachara
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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34
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Sasaki Y, Hackett AR, Kim S, Strickland A, Milbrandt J. Dysregulation of NAD + Metabolism Induces a Schwann Cell Dedifferentiation Program. J Neurosci 2018; 38:6546-6562. [PMID: 29921717 PMCID: PMC6052240 DOI: 10.1523/jneurosci.3304-17.2018] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 05/21/2018] [Accepted: 06/12/2018] [Indexed: 12/19/2022] Open
Abstract
The Schwann cell (SC) is the major component of the peripheral nervous system (PNS) that provides metabolic and functional support for peripheral axons. The emerging roles of SC mitochondrial function for PNS development and axonal stability indicate the importance of SC metabolism in nerve function and in peripheral neuropathies associated with metabolic disorders. Nicotinamide adenine dinucleotide (NAD+) is a crucial molecule in the regulation of cellular metabolism and redox homeostasis. Here, we investigated the roles of NAD+ metabolism in SC functions in vivo by mutating NAMPT, the rate-limiting enzyme of NAD+ biosynthesis, specifically in SCs. NAMPT SC knock-out male and female mice (NAMPT SCKO mice) had delayed SC maturation in development and developed hypomyelinating peripheral neuropathy without axon degeneration or decreased SC survival. JUN, a master regulator of SC dedifferentiation, is elevated in NAMPT SCKO SCs, suggesting that decreased NAD+ levels cause them to arrest at an immature stage. Nicotinic acid administration rescues the NAD+ decline and reverses the SC maturation defect and the development of peripheral neuropathy, indicating the central role of NAD+ in PNS development. Upon nicotinic acid withdrawal in adulthood, NAMPT SCKO mice showed rapid and severe peripheral neuropathy and activation of ERK/MEK/JUN signaling, which in turn promotes SC dedifferentiation. These data demonstrate the importance of NAD+ metabolism in SC maturation and nerve development and maintenance and suggest that altered SC NAD+ metabolism could underlie neuropathies associated with diabetes and aging.SIGNIFICANCE STATEMENT In this study, we showed that Schwann cell differentiation status is critically dependent on NAD+ homeostasis. Aberrant regulation of NAD+ biosynthesis via NAMPT deletion results in a blockade of Schwann cell maturation during development and severe peripheral neuropathy without significant axon loss. The phenotype can be rescued by supplementation with nicotinic acid; however, withdrawal of nicotinic acid leads to Schwann cell dedifferentiation, myelination defects, and death. These results provide new therapeutic possibilities for peripheral neuropathies associated with NAD+ decline during aging or diabetes.
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Affiliation(s)
- Yo Sasaki
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Amber R Hackett
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Sungsu Kim
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Amy Strickland
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Jeffrey Milbrandt
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri 63110
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35
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Schwann cell O-GlcNAcylation promotes peripheral nerve remyelination via attenuation of the AP-1 transcription factor JUN. Proc Natl Acad Sci U S A 2018; 115:8019-8024. [PMID: 30012597 DOI: 10.1073/pnas.1805538115] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Schwann cells (SCs), the glia of the peripheral nervous system, play an essential role in nerve regeneration. Upon nerve injury, SCs are reprogrammed into unique "repair SCs," and these cells remove degenerating axons/myelin debris, promote axonal regrowth, and ultimately remyelinate regenerating axons. The AP-1 transcription factor JUN is promptly induced in SCs upon nerve injury and potently mediates this injury-induced SC plasticity; however, the regulation of these JUN-dependent SC injury responses is unclear. Previously, we produced mice with a SC-specific deletion of O-GlcNAc transferase (OGT). This enzyme catalyzes O-GlcNAcylation, a posttranslational modification that is influenced by the cellular metabolic state. Mice lacking OGT in SCs develop a progressive demyelinating peripheral neuropathy. Here, we investigated the nerve repair process in OGT-SCKO mutant mice and found that the remyelination of regenerating axons is severely impaired. Gene expression profiling of OGT-SCKO SCs revealed that the JUN-dependent SC injury program was elevated in the absence of injury and failed to shut down at the appropriate time after injury. This aberrant JUN activity results in abnormalities in repair SC function and redifferentiation and prevents the timely remyelination. This aberrant nerve injury response is normalized in OGT-SCKO mice with reduced Jun gene dosage in SCs. Mechanistically, OGT O-GlcNAcylates JUN at multiple sites, which then leads to an attenuation of AP-1 transcriptional activity. Together, these results highlight the metabolic oversight of the nerve injury response via the regulation of JUN activity by O-GlcNAcylation, a pathway that could be important in the neuropathy associated with diabetes and aging.
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36
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Stassart RM, Möbius W, Nave KA, Edgar JM. The Axon-Myelin Unit in Development and Degenerative Disease. Front Neurosci 2018; 12:467. [PMID: 30050403 PMCID: PMC6050401 DOI: 10.3389/fnins.2018.00467] [Citation(s) in RCA: 131] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 06/19/2018] [Indexed: 12/15/2022] Open
Abstract
Axons are electrically excitable, cable-like neuronal processes that relay information between neurons within the nervous system and between neurons and peripheral target tissues. In the central and peripheral nervous systems, most axons over a critical diameter are enwrapped by myelin, which reduces internodal membrane capacitance and facilitates rapid conduction of electrical impulses. The spirally wrapped myelin sheath, which is an evolutionary specialisation of vertebrates, is produced by oligodendrocytes and Schwann cells; in most mammals myelination occurs during postnatal development and after axons have established connection with their targets. Myelin covers the vast majority of the axonal surface, influencing the axon's physical shape, the localisation of molecules on its membrane and the composition of the extracellular fluid (in the periaxonal space) that immerses it. Moreover, myelinating cells play a fundamental role in axonal support, at least in part by providing metabolic substrates to the underlying axon to fuel its energy requirements. The unique architecture of the myelinated axon, which is crucial to its function as a conduit over long distances, renders it particularly susceptible to injury and confers specific survival and maintenance requirements. In this review we will describe the normal morphology, ultrastructure and function of myelinated axons, and discuss how these change following disease, injury or experimental perturbation, with a particular focus on the role the myelinating cell plays in shaping and supporting the axon.
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Affiliation(s)
- Ruth M. Stassart
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
- Department of Neuropathology, University Medical Center Leipzig, Leipzig, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
| | - Julia M. Edgar
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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Lagerlöf O. O-GlcNAc cycling in the developing, adult and geriatric brain. J Bioenerg Biomembr 2018; 50:241-261. [PMID: 29790000 PMCID: PMC5984647 DOI: 10.1007/s10863-018-9760-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 05/07/2018] [Indexed: 12/14/2022]
Abstract
Hundreds of proteins in the nervous system are modified by the monosaccharide O-GlcNAc. A single protein is often O-GlcNAcylated on several amino acids and the modification of a single site can play a crucial role for the function of the protein. Despite its complexity, only two enzymes add and remove O-GlcNAc from proteins, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). Global and local regulation of these enzymes make it possible for O-GlcNAc to coordinate multiple cellular functions at the same time as regulating specific pathways independently from each other. If O-GlcNAcylation is disrupted, metabolic disorder or intellectual disability may ensue, depending on what neurons are affected. O-GlcNAc's promise as a clinical target for developing drugs against neurodegenerative diseases has been recognized for many years. Recent literature puts O-GlcNAc in the forefront among mechanisms that can help us better understand how neuronal circuits integrate diverse incoming stimuli such as fluctuations in nutrient supply, metabolic hormones, neuronal activity and cellular stress. Here the functions of O-GlcNAc in the nervous system are reviewed.
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Affiliation(s)
- Olof Lagerlöf
- Department of Neuroscience, Karolinska Institutet, 171 77, Stockholm, Sweden.
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38
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Aging Schwann cells: mechanisms, implications, future directions. Curr Opin Neurobiol 2017; 47:203-208. [DOI: 10.1016/j.conb.2017.10.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 10/11/2017] [Accepted: 10/24/2017] [Indexed: 12/17/2022]
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Abstract
O-GlcNAcylation - the attachment of O-linked N-acetylglucosamine (O-GlcNAc) moieties to cytoplasmic, nuclear and mitochondrial proteins - is a post-translational modification that regulates fundamental cellular processes in metazoans. A single pair of enzymes - O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) - controls the dynamic cycling of this protein modification in a nutrient- and stress-responsive manner. Recent years have seen remarkable advances in our understanding of O-GlcNAcylation at levels that range from structural and molecular biology to cell signalling and gene regulation to physiology and disease. New mechanisms and functions of O-GlcNAcylation that are emerging from these recent developments enable us to begin constructing a unified conceptual framework through which the significance of this modification in cellular and organismal physiology can be understood.
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Affiliation(s)
- Xiaoyong Yang
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Department of Comparative Medicine, Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
| | - Kevin Qian
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Department of Comparative Medicine, Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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40
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Della-Flora Nunes G, Mueller L, Silvestri N, Patel MS, Wrabetz L, Feltri ML, Poitelon Y. Acetyl-CoA production from pyruvate is not necessary for preservation of myelin. Glia 2017; 65:1626-1639. [PMID: 28657129 DOI: 10.1002/glia.23184] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 05/26/2017] [Accepted: 06/02/2017] [Indexed: 12/11/2022]
Abstract
Oligodendrocytes and Schwann cells not only form myelin in the central and peripheral nervous system, but also provide metabolic and trophic support to the axons they ensheathe. Acetyl-CoA is potentially a key molecule in Schwann cells and oligodendrocytes because it is at the crossroads of cellular lipid biosynthesis and energy generation. The main route for acetyl-CoA production is the oxidation of pyruvate by the pyruvate dehydrogenase complex (PDC). PDC deficiency in humans results in neurodegeneration and developmental impairments in both white and gray matter structures. To address the importance of PDC in myelinating glia, we deleted Pdha1 gene specifically in oligodendrocytes and Schwann cells. Surprisingly, sciatic and optic nerve morphology and the motor performance of Pdha1f/Y; CnpCre/+ mice are undistinguishable from those of controls at 1 month of age. In addition, myelin is stably maintained for at least 10 months. However, Pdha1f/Y; CnpCre/+ mice showed reduced fiber density and signs of axonal degeneration in both sciatic and optic nerves from 6 months of age. In contrast, 10 month-old mice bearing a floxed Pdha1 gene with either P0-Cre (expressed only by Schwann cells) or NG2-CreER (expressed in oligodendrocyte precursor cells) do not show any sign of axonal pathology or alterations in myelin structure or thickness. This indicates that the axonopathy is specific to the Pdha1f/Y; CnpCre/+ mice. Taken together, these results suggest that acetyl-CoA derived from pyruvate is not necessary for myelin maintenance and, thus, myelin-forming cells are not likely to contribute to the pathophysiology of PDC deficiency.
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Affiliation(s)
- Gustavo Della-Flora Nunes
- Hunter James Kelly Research Institute, University at Buffalo, Buffalo, New York, 14203.,Department of Biochemistry, University at Buffalo, Buffalo, New York, 14203
| | - Lauren Mueller
- Department of Biochemistry, University at Buffalo, Buffalo, New York, 14203
| | - Nicholas Silvestri
- Deptartment of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, 14203
| | - Mulchand S Patel
- Department of Biochemistry, University at Buffalo, Buffalo, New York, 14203
| | - Lawrence Wrabetz
- Hunter James Kelly Research Institute, University at Buffalo, Buffalo, New York, 14203.,Department of Biochemistry, University at Buffalo, Buffalo, New York, 14203.,Deptartment of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, 14203
| | - M Laura Feltri
- Hunter James Kelly Research Institute, University at Buffalo, Buffalo, New York, 14203.,Department of Biochemistry, University at Buffalo, Buffalo, New York, 14203.,Deptartment of Neurology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, 14203
| | - Yannick Poitelon
- Hunter James Kelly Research Institute, University at Buffalo, Buffalo, New York, 14203.,Department of Biochemistry, University at Buffalo, Buffalo, New York, 14203
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Protein O-GlcNAcylation: emerging mechanisms and functions. Nat Rev Mol Cell Biol 2017. [PMID: 28488703 DOI: 10.1038/nrm.2017.22,+10.1038/nrn.2017.89,+10.1038/nrn.2017.87] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
O-GlcNAcylation - the attachment of O-linked N-acetylglucosamine (O-GlcNAc) moieties to cytoplasmic, nuclear and mitochondrial proteins - is a post-translational modification that regulates fundamental cellular processes in metazoans. A single pair of enzymes - O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) - controls the dynamic cycling of this protein modification in a nutrient- and stress-responsive manner. Recent years have seen remarkable advances in our understanding of O-GlcNAcylation at levels that range from structural and molecular biology to cell signalling and gene regulation to physiology and disease. New mechanisms and functions of O-GlcNAcylation that are emerging from these recent developments enable us to begin constructing a unified conceptual framework through which the significance of this modification in cellular and organismal physiology can be understood.
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42
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Abstract
O-GlcNAcylation - the attachment of O-linked N-acetylglucosamine (O-GlcNAc) moieties to cytoplasmic, nuclear and mitochondrial proteins - is a post-translational modification that regulates fundamental cellular processes in metazoans. A single pair of enzymes - O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) - controls the dynamic cycling of this protein modification in a nutrient- and stress-responsive manner. Recent years have seen remarkable advances in our understanding of O-GlcNAcylation at levels that range from structural and molecular biology to cell signalling and gene regulation to physiology and disease. New mechanisms and functions of O-GlcNAcylation that are emerging from these recent developments enable us to begin constructing a unified conceptual framework through which the significance of this modification in cellular and organismal physiology can be understood.
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齐 琦, 朱 安, 吕 合, 胡 建. [Conditioned medium from rat RSC96 cells promotes proliferation of oligodendrocyte progenitor cells in vitro]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2017; 37:317-322. [PMID: 28377346 PMCID: PMC6780444 DOI: 10.3969/j.issn.1673-4254.2017.03.07] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Indexed: 06/07/2023]
Abstract
OBJECTIVE To investigate the effect of conditioned medium from rat RSC96 cells (RSC96-CM) on the proliferation of oligodendrocyte progenitor cells (OPCs) and explore the underlying mechanism. METHODS OPCs isolated from the spinal cords of SD rats of embryonic day 15 using immunopanning were treated with RSC96-CM. The proliferation of OPCs was detected using 5-bromo-2'-deoxyuridine (BrdU) incorporation assay. The mRNA expressions of PDGF-AA and bFGF in RSC96 cells were detected using RT-PCR, and their protein concentrations in RSC96-CM were detected with enzyme-linked immunosorbent assay (ELISA). The effects of PDGF-AA and bFGF in RSC96-CM on OPC proliferation and the roles of ERK and JNK signaling pathways in RSC96-CM-induced OPC proliferation were determined by application of their specific inhibitors. RESULTS The percentage of BrdU+ OPCs was significantly increased in response to treatment with RSC96-CM (P<0.05), reaching the peak level when 50% RSC96-CM was added in the cell culture. RSC96 cells expressed a substantial amount of PDGF-AA and bFGF mRNAs, and PDGF-AA and bFGF protein concentrations in RSC96-CM were higher than those in a conditioned medium (B104CM) we used previously by 0.87 and 0.92 folds, respectively. Both the specific inhibitor of PDGFR signal pathway (AG1295) and the specific inhibitor of bFGFR signal pathway (PD173074) significantly attenuated RSC96-CM-induced OPC proliferation. The specific inhibitors of ERK signal pathway (U0126) and JNK signal pathway (SP600125) significantly decreased the percentage of BrdU+ cells in RSC96-CM-induced OPCs (P<0.01). CONCLUSION RSC96-CM can effectively promote OPC proliferation, possibly as a result of PDGF-AA and bFGF secretion by RSC96 cells to activate ERK1/2 and JNK signaling pathways. RSC96- CM can be used as a routine stimulator for promoting OPC proliferation.
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Affiliation(s)
- 琦 齐
- 蚌埠医学院,组织学与胚胎学教研室,安徽 蚌埠 233030Department of Histology and Embryology, Bengbu Medical College, Bengbu 233030, China
- 蚌埠医学院,组织移植安徽省重点实验室,安徽 蚌埠 233030Anhui Key Laboratory of Tissue Transplantation, Bengbu 233030, China
| | - 安友 朱
- 蚌埠医学院,组织移植安徽省重点实验室,安徽 蚌埠 233030Anhui Key Laboratory of Tissue Transplantation, Bengbu 233030, China
- 第一附属医院检验科,安徽 蚌埠 233004Clinical Laboratory, First Affiliated Hospital of Bengbu Medical College, Bengbu 233004, China
| | - 合作 吕
- 蚌埠医学院,组织移植安徽省重点实验室,安徽 蚌埠 233030Anhui Key Laboratory of Tissue Transplantation, Bengbu 233030, China
- 第一附属医院检验科,安徽 蚌埠 233004Clinical Laboratory, First Affiliated Hospital of Bengbu Medical College, Bengbu 233004, China
| | - 建国 胡
- 蚌埠医学院,组织移植安徽省重点实验室,安徽 蚌埠 233030Anhui Key Laboratory of Tissue Transplantation, Bengbu 233030, China
- 第一附属医院检验科,安徽 蚌埠 233004Clinical Laboratory, First Affiliated Hospital of Bengbu Medical College, Bengbu 233004, China
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Barton MJ, John JS, Clarke M, Wright A, Ekberg J. The Glia Response after Peripheral Nerve Injury: A Comparison between Schwann Cells and Olfactory Ensheathing Cells and Their Uses for Neural Regenerative Therapies. Int J Mol Sci 2017; 18:E287. [PMID: 28146061 PMCID: PMC5343823 DOI: 10.3390/ijms18020287] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 01/14/2017] [Accepted: 01/17/2017] [Indexed: 01/04/2023] Open
Abstract
The peripheral nervous system (PNS) exhibits a much larger capacity for regeneration than the central nervous system (CNS). One reason for this difference is the difference in glial cell types between the two systems. PNS glia respond rapidly to nerve injury by clearing debris from the injury site, supplying essential growth factors and providing structural support; all of which enhances neuronal regeneration. Thus, transplantation of glial cells from the PNS is a very promising therapy for injuries to both the PNS and the CNS. There are two key types of PNS glia: olfactory ensheathing cells (OECs), which populate the olfactory nerve, and Schwann cells (SCs), which are present in the rest of the PNS. These two glial types share many similar morphological and functional characteristics but also exhibit key differences. The olfactory nerve is constantly turning over throughout life, which means OECs are continuously stimulating neural regeneration, whilst SCs only promote regeneration after direct injury to the PNS. This review presents a comparison between these two PNS systems in respect to normal physiology, developmental anatomy, glial functions and their responses to injury. A thorough understanding of the mechanisms and differences between the two systems is crucial for the development of future therapies using transplantation of peripheral glia to treat neural injuries and/or disease.
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Affiliation(s)
- Matthew J Barton
- Menzies Health Institute Queensland, Griffith University, Nathan QLD 4111, Australia.
- Clem Jones Centre for Neurobiology & Stem Cell Research, Griffith University, Nathan QLD 4111, Australia.
| | - James St John
- Menzies Health Institute Queensland, Griffith University, Nathan QLD 4111, Australia.
- Clem Jones Centre for Neurobiology & Stem Cell Research, Griffith University, Nathan QLD 4111, Australia.
- Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD 4111, Australia.
| | - Mary Clarke
- Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD 4111, Australia.
| | - Alison Wright
- Faculty of Health and Medical Science, Bond University, Robina, QLD 4226, Australia.
| | - Jenny Ekberg
- Clem Jones Centre for Neurobiology & Stem Cell Research, Griffith University, Nathan QLD 4111, Australia.
- Faculty of Health and Medical Science, Bond University, Robina, QLD 4226, Australia.
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O-GlcNAc Transferase Is Essential for Sensory Neuron Survival and Maintenance. J Neurosci 2017; 37:2125-2136. [PMID: 28115479 DOI: 10.1523/jneurosci.3384-16.2017] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 12/12/2016] [Accepted: 01/03/2017] [Indexed: 11/21/2022] Open
Abstract
O-GlcNAc transferase (OGT) regulates a wide range of cellular processes through the addition of the O-GlcNAc sugar moiety to thousands of protein substrates. Because nutrient availability affects the activity of OGT, its role has been broadly studied in metabolic tissues. OGT is enriched in the nervous system, but little is known about its importance in basic neuronal processes in vivo Here, we show that OGT is essential for sensory neuron survival and maintenance in mice. Sensory neuron-specific knock-out of OGT results in behavioral hyposensitivity to thermal and mechanical stimuli accompanied by decreased epidermal innervation and cell-body loss in the dorsal root ganglia. These effects are observed early in postnatal development and progress as animals age. Cultured sensory neurons lacking OGT also exhibit decreased axonal outgrowth. The effects on neuronal health in vivo are not solely due to disruption of developmental processes, because inducing OGT knock-out in the sensory neurons of adult mice results in a similar decrease in nerve fiber endings and cell bodies. Significant nerve-ending loss occurs before a decrease in cell bodies; this phenotype is indicative of axonal dieback that progresses to neuronal death. Our findings demonstrate that OGT is important in regulating axonal maintenance in the periphery and the overall health and survival of sensory neurons.SIGNIFICANCE STATEMENT We show the importance of O-GlcNAc transferase (OGT) for sensory neuron health and survival in vivo This study is the first to find that loss of OGT results in neuronal cell death. Moreover, it suggests that aberrant O-GlcNAc signaling can contribute to the development of neuropathy. The sensory neurons lie outside of the blood-brain barrier and therefore, compared to central neurons, may have a greater need for mechanisms of metabolic sensing and compensation. Peripheral sensory neurons in particular are subject to degeneration in diabetes. Our findings provide a foundation for understanding the role of OGT under normal physiological conditions in the peripheral nervous system. This knowledge will be important for gaining greater insight into such disease states as diabetic neuropathy.
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