1
|
Wu S, Lin W. The physiological role of the unfolded protein response in the nervous system. Neural Regen Res 2024; 19:2411-2420. [PMID: 38526277 PMCID: PMC11090440 DOI: 10.4103/1673-5374.393105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Accepted: 12/12/2023] [Indexed: 03/26/2024] Open
Abstract
The unfolded protein response (UPR) is a cellular stress response pathway activated when the endoplasmic reticulum, a crucial organelle for protein folding and modification, encounters an accumulation of unfolded or misfolded proteins. The UPR aims to restore endoplasmic reticulum homeostasis by enhancing protein folding capacity, reducing protein biosynthesis, and promoting protein degradation. It also plays a pivotal role in coordinating signaling cascades to determine cell fate and function in response to endoplasmic reticulum stress. Recent research has highlighted the significance of the UPR not only in maintaining endoplasmic reticulum homeostasis but also in influencing various physiological processes in the nervous system. Here, we provide an overview of recent findings that underscore the UPR's involvement in preserving the function and viability of neuronal and myelinating cells under physiological conditions, and highlight the critical role of the UPR in brain development, memory storage, retinal cone development, myelination, and maintenance of myelin thickness.
Collapse
Affiliation(s)
- Shuangchan Wu
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, USA
- Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, USA
| | - Wensheng Lin
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, USA
- Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, USA
| |
Collapse
|
2
|
Gao Y, Slomnicki LP, Kilanczyk E, Forston MD, Pietrzak M, Rouchka EC, Howard RM, Whittemore SR, Hetman M. Reduced Expression of Oligodendrocyte Linage-Enriched Transcripts During the Endoplasmic Reticulum Stress/Integrated Stress Response. ASN Neuro 2024; 16:2371162. [PMID: 39024571 DOI: 10.1080/17590914.2024.2371162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Accepted: 04/12/2024] [Indexed: 07/20/2024] Open
Abstract
Endoplasmic reticulum (ER) stress in oligodendrocyte (OL) linage cells contributes to several CNS pathologies including traumatic spinal cord injury (SCI) and multiple sclerosis. Therefore, primary rat OL precursor cell (OPC) transcriptomes were analyzed using RNASeq after treatments with two ER stress-inducing drugs, thapsigargin (TG) or tunicamycin (TM). Gene ontology term (GO) enrichment showed that both drugs upregulated mRNAs associated with the general stress response. The GOs related to ER stress were only enriched for TM-upregulated mRNAs, suggesting greater ER stress selectivity of TM. Both TG and TM downregulated cell cycle/cell proliferation-associated transcripts, indicating the anti-proliferative effects of ER stress. Interestingly, many OL lineage-enriched mRNAs were downregulated, including those for transcription factors that drive OL identity such as Olig2. Moreover, ER stress-associated decreases of OL-specific gene expression were found in mature OLs from mouse models of white matter pathologies including contusive SCI, toxin-induced demyelination, and Alzheimer's disease-like neurodegeneration. Taken together, the disrupted transcriptomic fingerprint of OL lineage cells may facilitate myelin degeneration and/or dysfunction when pathological ER stress persists in OL lineage cells.
Collapse
Affiliation(s)
- Yonglin Gao
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Departments of Neurological Surgery, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Lukasz P Slomnicki
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Departments of Neurological Surgery, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Ewa Kilanczyk
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Departments of Neurological Surgery, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Michael D Forston
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Departments of Neurological Surgery, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Maciej Pietrzak
- Department of Biomedical Informatics, The Ohio State University, Columbus, Ohio, USA
| | - Eric C Rouchka
- Kentucky Biomedical Research Infrastructure Network Bioinformatics Core, University of Louisville, Louisville, Kentucky, USA
| | - Russell M Howard
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Departments of Neurological Surgery, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Scott R Whittemore
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Departments of Neurological Surgery, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Anatomical Sciences & Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Pharmacology & Toxicology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Michal Hetman
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Departments of Neurological Surgery, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Anatomical Sciences & Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Pharmacology & Toxicology, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, Kentucky, USA
| |
Collapse
|
3
|
Saraswat Ohri S, Forston MD, Myers SA, Brown BL, Andres KR, Howard RM, Gao Y, Liu Y, Cavener DR, Hetman M, Whittemore SR. Oligodendrocyte-selective deletion of the eIF2α kinase Perk/Eif2ak3 limits functional recovery after spinal cord injury. Glia 2024; 72:1259-1272. [PMID: 38587137 DOI: 10.1002/glia.24525] [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: 02/01/2023] [Revised: 02/13/2024] [Accepted: 03/04/2024] [Indexed: 04/09/2024]
Abstract
After spinal cord injury (SCI), re-establishing cellular homeostasis is critical to optimize functional recovery. Central to that response is PERK signaling, which ultimately initiates a pro-apoptotic response if cellular homeostasis cannot be restored. Oligodendrocyte (OL) loss and white matter damage drive functional consequences and determine recovery potential after thoracic contusive SCI. We examined acute (<48 h post-SCI) and chronic (6 weeks post-SCI) effects of conditionally deleting Perk from OLs prior to SCI. While Perk transcript is expressed in many types of cells in the adult spinal cord, its levels are disproportionately high in OL lineage cells. Deletion of OL-Perk prior to SCI resulted in: (1) enhanced acute phosphorylation of eIF2α, a major PERK substrate and the critical mediator of the integrated stress response (ISR), (2) enhanced acute expression of the downstream ISR genes Atf4, Ddit3/Chop, and Tnfrsf10b/Dr5, (3) reduced acute OL lineage-specific Olig2 mRNA, but not neuronal or astrocytic mRNAs, (4) chronically decreased OL content in the spared white matter at the injury epicenter, (5) impaired hindlimb locomotor recovery, and (6) reduced chronic epicenter white matter sparing. Cultured primary OL precursor cells with reduced PERK expression and activated ER stress response showed: (1) unaffected phosphorylation of eIF2α, (2) enhanced ISR gene induction, and (3) increased cytotoxicity. Therefore, OL-Perk deficiency exacerbates ISR signaling and potentiates white matter damage after SCI. The latter effect is likely mediated by increased loss of Perk-/- OLs.
Collapse
Affiliation(s)
- Sujata Saraswat Ohri
- Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, USA
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Interdisciplinary Program in Translational Neuroscience, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Michael D Forston
- Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, USA
- Department of Anatomical Sciences & Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Scott A Myers
- Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, USA
| | - Brandon L Brown
- Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, USA
- Department of Interdisciplinary Program in Translational Neuroscience, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Anatomical Sciences & Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Kariena R Andres
- Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, USA
| | - Russell M Howard
- Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, USA
| | - Yonglin Gao
- Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, USA
| | - Yu Liu
- Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, USA
| | - Douglas R Cavener
- Department of Biology, Penn State University, University Park, Pennsylvania, USA
| | - Michal Hetman
- Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, USA
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Interdisciplinary Program in Translational Neuroscience, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Anatomical Sciences & Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Pharmacology & Toxicology, University of Louisville School of Medicine, Louisville, Kentucky, USA
- M.D./Ph.D. Program, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Scott R Whittemore
- Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky, USA
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Interdisciplinary Program in Translational Neuroscience, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Anatomical Sciences & Neurobiology, University of Louisville School of Medicine, Louisville, Kentucky, USA
- Department of Pharmacology & Toxicology, University of Louisville School of Medicine, Louisville, Kentucky, USA
- M.D./Ph.D. Program, University of Louisville School of Medicine, Louisville, Kentucky, USA
| |
Collapse
|
4
|
Vidicevic S, Tasic J, Stanojevic Z, Ciric D, Martinovic T, Paunovic V, Petricevic S, Tomonjic N, Isakovic A, Trajkovic V. Endoplasmic reticulum stress response in immune cells contributes to experimental autoimmune encephalomyelitis pathogenesis in rats. Immunol Lett 2024; 267:106855. [PMID: 38537720 DOI: 10.1016/j.imlet.2024.106855] [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: 05/29/2023] [Revised: 11/28/2023] [Accepted: 03/23/2024] [Indexed: 04/01/2024]
Abstract
We examined the role of endoplasmic reticulum (ER) stress and the ensuing unfolded protein response (UPR) in the development of the central nervous system (CNS)-directed immune response in the rat model of experimental autoimmune encephalomyelitis (EAE). The induction of EAE with syngeneic spinal cord homogenate in complete Freund's adjuvant (CFA) caused a time-dependent increase in the expression of ER stress/UPR markers glucose-regulated protein 78 (GRP78), X-box-binding protein 1 (XBP1), C/EBP homologous protein (CHOP), and phosphorylated eukaryotic initiation factor 2α (eIF2α) in the draining lymph nodes of both EAE-susceptible Dark Agouti (DA) and EAE-resistant Albino Oxford (AO) rats. However, the increase in ER stress markers was more pronounced in AO rats. CFA alone also induced ER stress, but the effect was weaker and less sustained compared to full immunization. The ultrastructural analysis of DA lymph node tissue by electron microscopy revealed ER dilatation in lymphocytes, macrophages, and plasma cells, while immunoblot analysis of CD3-sorted lymph node cells demonstrated the increase in ER stress/UPR markers in both CD3+ (T cell) and CD3- (non-T) cell compartments. A positive correlation was observed between the levels of ER stress/UPR markers in the CNS-infiltrated mononuclear cells and the clinical activity of the disease. Finally, the reduction of EAE clinical signs by ER stress inhibitor ursodeoxycholic acid was associated with the decrease in the expression of mRNA encoding pro-inflammatory cytokines TNF and IL-1β, and encephalitogenic T cell cytokines IFN-γ and IL-17. Collectively, our data indicate that ER stress response in immune cells might be an important pathogenetic factor and a valid therapeutic target in the inflammatory damage of the CNS.
Collapse
Affiliation(s)
- Sasenka Vidicevic
- Institute of Medical and Clinical Biochemistry, Faculty of Medicine, University of Belgrade, 11000, Belgrade, Serbia
| | - Jelena Tasic
- Institute of Medical and Clinical Biochemistry, Faculty of Medicine, University of Belgrade, 11000, Belgrade, Serbia
| | - Zeljka Stanojevic
- Institute of Medical and Clinical Biochemistry, Faculty of Medicine, University of Belgrade, 11000, Belgrade, Serbia.
| | - Darko Ciric
- Institute of Histology and Embryology, Faculty of Medicine, University of Belgrade, 11000, Belgrade, Serbia
| | - Tamara Martinovic
- Institute of Histology and Embryology, Faculty of Medicine, University of Belgrade, 11000, Belgrade, Serbia
| | - Verica Paunovic
- Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, 11000, Belgrade, Serbia
| | - Sasa Petricevic
- Institute of Medical and Clinical Biochemistry, Faculty of Medicine, University of Belgrade, 11000, Belgrade, Serbia
| | - Nina Tomonjic
- Institute of Medical and Clinical Biochemistry, Faculty of Medicine, University of Belgrade, 11000, Belgrade, Serbia; Institute of Rheumatology, Faculty of Medicine, University of Belgrade, 11000, Belgrade, Serbia
| | - Aleksandra Isakovic
- Institute of Medical and Clinical Biochemistry, Faculty of Medicine, University of Belgrade, 11000, Belgrade, Serbia
| | - Vladimir Trajkovic
- Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, 11000, Belgrade, Serbia
| |
Collapse
|
5
|
Lei Z, Lin W. Mechanisms Governing Oligodendrocyte Viability in Multiple Sclerosis and Its Animal Models. Cells 2024; 13:116. [PMID: 38247808 PMCID: PMC10814231 DOI: 10.3390/cells13020116] [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: 12/14/2023] [Revised: 01/04/2024] [Accepted: 01/05/2024] [Indexed: 01/23/2024] Open
Abstract
Multiple sclerosis (MS) is a chronic autoimmune inflammatory demyelinating disease of the central nervous system (CNS), which is triggered by an autoimmune assault targeting oligodendrocytes and myelin. Recent research indicates that the demise of oligodendrocytes due to an autoimmune attack contributes significantly to the pathogenesis of MS and its animal model experimental autoimmune encephalomyelitis (EAE). A key challenge in MS research lies in comprehending the mechanisms governing oligodendrocyte viability and devising therapeutic approaches to enhance oligodendrocyte survival. Here, we provide an overview of recent findings that highlight the contributions of oligodendrocyte death to the development of MS and EAE and summarize the current literature on the mechanisms governing oligodendrocyte viability in these diseases.
Collapse
Affiliation(s)
- Zhixin Lei
- School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan 430070, China;
| | - Wensheng Lin
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
- Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| |
Collapse
|
6
|
Bracchi-Ricard V, Nguyen K, Ricci D, Gaudette B, Henao-Meija J, Brambilla R, Martynyuk T, Gidalevitz T, Allman D, Bethea JR, Argon Y. Increased activity of IRE1 improves the clinical presentation of EAE. FASEB J 2023; 37:e23283. [PMID: 37983957 PMCID: PMC10662669 DOI: 10.1096/fj.202300769rr] [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: 04/19/2023] [Revised: 10/03/2023] [Accepted: 10/17/2023] [Indexed: 11/22/2023]
Abstract
Activation of the endoplasmic reticulum (ER) stress sensor inositol-requiring enzyme-1α (IRE1α) contributes to neuronal development and is known to induce neuronal remodeling in vitro and in vivo. On the contrary, excessive IRE1 activity is often detrimental and may contribute to neurodegeneration. To determine the consequences of increased activation of IRE1α, we used a mouse model expressing a C148S variant of IRE1α with increased and sustained activation. Surprisingly, the mutation did not affect the differentiation of highly secretory antibody-producing cells but exhibited a beneficial effect in a mouse model of experimental autoimmune encephalomyelitis (EAE). Although mechanical allodynia was unaffected, significant improvement in motor function was found in IRE1C148S mice with EAE relative to wild type (WT) mice. Coincident with this improvement, there was reduced microgliosis in the spinal cord of IRE1C148S mice, with reduced expression of proinflammatory cytokine genes. This was accompanied by reduced axonal degeneration and enhanced 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) levels, suggesting improved myelin integrity. Interestingly, while the IRE1C148S mutation is expressed in all cells, the reduction in proinflammatory cytokines and in the microglial activation marker ionized calcium-binding adapter molecule (IBA1), along with preservation of phagocytic gene expression, all point to microglia as the cell type contributing to the clinical improvement in IRE1C148S animals. Our data suggest that sustained increase in IRE1α activity can be beneficial in vivo, and that this protection is cell type and context dependent. Considering the overwhelming but conflicting evidence for the role of ER stress in neurological diseases, a better understanding of the function of ER stress sensors in physiological contexts is clearly needed.
Collapse
Affiliation(s)
| | - Kayla Nguyen
- Department of Biology, Drexel University, Philadelphia, PA
| | - Daniela Ricci
- Department of Pathology and Lab Medicine, The Children’s Hospital of Philadelphia and the University of Pennsylvania, Philadelphia, PA, USA
| | - Brian Gaudette
- Department of Pathology and Lab Medicine, the University of Pennsylvania, Philadelphia, PA, USA
| | - Jorge Henao-Meija
- Department of Pathology and Lab Medicine, The Children’s Hospital of Philadelphia and the University of Pennsylvania, Philadelphia, PA, USA
| | - Roberta Brambilla
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, USA
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, 5000 Odense, Denmark
- BRIDGE - Brain Research - Inter-Disciplinary Guided Excellence, Department of Clinical Research, University of Southern Denmark, 5000 Odense, Denmark
| | | | | | - David Allman
- Department of Pathology and Lab Medicine, the University of Pennsylvania, Philadelphia, PA, USA
| | - John R. Bethea
- Department of Biology, Drexel University, Philadelphia, PA
| | - Yair Argon
- Department of Pathology and Lab Medicine, The Children’s Hospital of Philadelphia and the University of Pennsylvania, Philadelphia, PA, USA
| |
Collapse
|
7
|
Talukdar G, Orr HT, Lei Z. The PERK pathway: beneficial or detrimental for neurodegenerative diseases and tumor growth and cancer. Hum Mol Genet 2023; 32:2545-2557. [PMID: 37384418 PMCID: PMC10407711 DOI: 10.1093/hmg/ddad103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 06/04/2023] [Accepted: 06/05/2023] [Indexed: 07/01/2023] Open
Abstract
Protein kinase R (PKR)-like endoplasmic reticulum (ER) kinase (PERK) is one of the three major sensors in the unfolded protein response (UPR). The UPR is involved in the modulation of protein synthesis as an adaptive response. Prolonged PERK activity correlates with the development of diseases and the attenuation of disease severity. Thus, the current debate focuses on the role of the PERK signaling pathway either in accelerating or preventing diseases such as neurodegenerative diseases, myelin disorders, and tumor growth and cancer. In this review, we examine the current findings on the PERK signaling pathway and whether it is beneficial or detrimental for the above-mentioned disorders.
Collapse
Affiliation(s)
- Gourango Talukdar
- Institute for Translational Neuroscience and Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, USA
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, USA
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | - Harry T Orr
- Institute for Translational Neuroscience and Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, USA
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Zhixin Lei
- Institute for Translational Neuroscience and Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, USA
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| |
Collapse
|
8
|
Bracchi-Ricard V, Nguyen K, Ricci D, Gaudette B, Henao-Meija J, Brambilla R, Martynyuk T, Gidalevitz T, Allman D, Bethea JR, Argon Y. Increased activity of IRE1 improves the clinical presentation of EAE. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.19.537391. [PMID: 37131811 PMCID: PMC10153167 DOI: 10.1101/2023.04.19.537391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Activation of the ER stress sensor IRE1α contributes to neuronal development and is known to induce neuronal remodeling in vitro and in vivo. On the other hand, excessive IRE1 activity is often detrimental and may contribute to neurodegeneration. To determine the consequences of increased activation of IRE1α, we used a mouse model expressing a C148S variant of IRE1α with increased and sustained activation. Surprisingly, the mutation did not affect the differentiation of highly secretory antibody-producing cells, but exhibited a strong protective effect in a mouse model of experimental autoimmune encephalomyelitis (EAE). Significant improvement in motor function was found in IRE1C148S mice with EAE relative to WT mice. Coincident with this improvement, there was reduced microgliosis in the spinal cord of IRE1C148S mice, with reduced expression of pro-inflammatory cytokine genes. This was accompanied by reduced axonal degeneration and enhanced CNPase levels, suggestiing improved myelin integrity. Interestingly, while the IRE1C148S mutation is expressed in all cells, the reduction in proinflammatory cytokines and in the activation of microglial activation marker IBA1, along with preservation of phagocytic gene expression, all point to microglia as the cell type contributing to the clinical improvement in IRE1C148S animals. Our data suggest that sustained increase in IRE1α activity can be protective in vivo, and that this protection is cell type and context dependent. Considering the overwhelming but conflicting evidence for the role of the ER stress in neurological diseases, a better understanding of the function of ER stress sensors in physiological contexts is clearly needed.
Collapse
Affiliation(s)
| | - Kayla Nguyen
- Department of Biology, Drexel University, Philadelphia, PA
| | - Daniela Ricci
- Department of Pathology and Lab Medicine, The Children's Hospital of Philadelphia and the University of Pennsylvania, Philadelphia, PA, USA
| | - Brian Gaudette
- Department of Pathology and Lab Medicine, the University of Pennsylvania, Philadelphia, PA, USA
| | - Jorge Henao-Meija
- Department of Pathology and Lab Medicine, The Children's Hospital of Philadelphia and the University of Pennsylvania, Philadelphia, PA, USA
| | - Roberta Brambilla
- The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL, USA
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, 5000 Odense, Denmark
- BRIDGE - Brain Research - Inter-Disciplinary Guided Excellence, Department of Clinical Research, University of Southern Denmark, 5000 Odense, Denmark
| | | | | | - David Allman
- Department of Pathology and Lab Medicine, the University of Pennsylvania, Philadelphia, PA, USA
| | - John R Bethea
- Department of Biology, Drexel University, Philadelphia, PA
| | - Yair Argon
- Department of Pathology and Lab Medicine, The Children's Hospital of Philadelphia and the University of Pennsylvania, Philadelphia, PA, USA
| |
Collapse
|
9
|
Shi M, Chai Y, Zhang J, Chen X. Endoplasmic Reticulum Stress-Associated Neuronal Death and Innate Immune Response in Neurological Diseases. Front Immunol 2022; 12:794580. [PMID: 35082783 PMCID: PMC8784382 DOI: 10.3389/fimmu.2021.794580] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 12/17/2021] [Indexed: 12/13/2022] Open
Abstract
Neuronal death and inflammatory response are two common pathological hallmarks of acute central nervous system injury and chronic degenerative disorders, both of which are closely related to cognitive and motor dysfunction associated with various neurological diseases. Neurological diseases are highly heterogeneous; however, they share a common pathogenesis, that is, the aberrant accumulation of misfolded/unfolded proteins within the endoplasmic reticulum (ER). Fortunately, the cell has intrinsic quality control mechanisms to maintain the proteostasis network, such as chaperone-mediated folding and ER-associated degradation. However, when these control mechanisms fail, misfolded/unfolded proteins accumulate in the ER lumen and contribute to ER stress. ER stress has been implicated in nearly all neurological diseases. ER stress initiates the unfolded protein response to restore proteostasis, and if the damage is irreversible, it elicits intracellular cascades of death and inflammation. With the growing appreciation of a functional association between ER stress and neurological diseases and with the improved understanding of the multiple underlying molecular mechanisms, pharmacological and genetic targeting of ER stress are beginning to emerge as therapeutic approaches for neurological diseases.
Collapse
Affiliation(s)
- Mingming Shi
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin, China.,Tianjin Neurological Institute, Key Laboratory of Post-trauma Neuro-Repair and Regeneration in Central Nervous System, Ministry of Education, Tianjin, China.,Department of Neurosurgery, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, Tianjin, China
| | - Yan Chai
- Tianjin Neurological Institute, Key Laboratory of Post-trauma Neuro-Repair and Regeneration in Central Nervous System, Ministry of Education, Tianjin, China.,Department of Neurosurgery, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, Tianjin, China
| | - Jianning Zhang
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin, China.,Tianjin Neurological Institute, Key Laboratory of Post-trauma Neuro-Repair and Regeneration in Central Nervous System, Ministry of Education, Tianjin, China.,Department of Neurosurgery, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, Tianjin, China
| | - Xin Chen
- Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin, China.,Tianjin Neurological Institute, Key Laboratory of Post-trauma Neuro-Repair and Regeneration in Central Nervous System, Ministry of Education, Tianjin, China.,Department of Neurosurgery, Tianjin Key Laboratory of Injuries, Variations and Regeneration of Nervous System, Tianjin, China
| |
Collapse
|
10
|
Roth LM, Akay-Espinoza C, Grinspan JB, Jordan-Sciutto KL. HIV-induced neuroinflammation inhibits oligodendrocyte maturation via glutamate-dependent activation of the PERK arm of the integrated stress response. Glia 2021; 69:2252-2271. [PMID: 34058792 DOI: 10.1002/glia.24033] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 05/14/2021] [Accepted: 05/17/2021] [Indexed: 12/15/2022]
Abstract
Despite combined antiretroviral therapy (cART), HIV-associated neurocognitive disorder (HAND) affects 30-50% of HIV-positive patients. Importantly, persistent white matter pathologies, specifically corpus callosum thinning and disruption of white matter microstructures observed in patients with HAND despite viral control through cART, raise the possibility that HIV infection in the setting of suboptimal cART may perturb oligodendrocyte (OL) maturation, function and/or survival, influencing HAND persistence in the cART era. To examine the effect of HIV infection on OL maturation, we used supernatants of primary human monocyte-derived macrophages infected with HIV (HIV/MDMs) to treat primary cultures of rat oligodendrocyte precursor cells (OPCs) during their differentiation to mature OLs. Using immunostaining for lineage-specific markers, we found that HIV/MDMs significantly inhibited OPC maturation. Based on our previous studies, we examined the potential role of several signaling pathways, including ionotropic glutamate receptors and the integrated stress response (ISR), and found that AMPA receptors (AMPAR)/kainic acid (KA) receptors (KARs) mediated the HIV/MDMs-induced defect in OL maturation. We also found that the treatment of OPC cultures with glutamate or AMPAR/KAR agonists phenocopied this effect. Blocking ISR activation, specifically the PERK arm of the ISR, protected OPCs from HIV/MDMs-mediated inhibition of OL maturation. Further, while glutamate, AMPA, and KA activated the ISR, inhibition of AMPAR/KAR activation prevented ISR induction in OPCs and rescued OL maturation. Collectively, these data identify glutamate signaling via ISR activation as a potential therapeutic pathway to ameliorate white matter pathologies in HAND and highlight the need for further investigation of their contribution to cognitive impairment.
Collapse
Affiliation(s)
- Lindsay M Roth
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Department of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Cagla Akay-Espinoza
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Judith B Grinspan
- Department of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Kelly L Jordan-Sciutto
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| |
Collapse
|
11
|
Sen MK, Hossain MJ. Oligodendrocyte-Specific Mechanisms of Myelin Thinning: Implications for Neurodegenerative Diseases. Front Neurosci 2021; 15:663053. [PMID: 33841096 PMCID: PMC8024530 DOI: 10.3389/fnins.2021.663053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 03/01/2021] [Indexed: 12/21/2022] Open
Affiliation(s)
- Monokesh K Sen
- School of Medicine, Western Sydney University, Penrith, NSW, Australia.,Peter Duncan Neuroscience Research Unit, St. Vincent's Centre for Applied Medical Research, Darlinghurst, Sydney, NSW, Australia
| | | |
Collapse
|
12
|
The Integrated UPR and ERAD in Oligodendrocytes Maintain Myelin Thickness in Adults by Regulating Myelin Protein Translation. J Neurosci 2020; 40:8214-8232. [PMID: 32958569 DOI: 10.1523/jneurosci.0604-20.2020] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 08/09/2020] [Accepted: 09/10/2020] [Indexed: 12/12/2022] Open
Abstract
Myelin proteins, which are produced in the endoplasmic reticulum (ER), are essential and necessary for maintaining myelin structure. The integrated unfold protein response (UPR) and ER-associated degradation (ERAD) are the primary ER quality control mechanism. The adaptor protein Sel1L (Suppressor/Enhancer of Lin-12-like) controls the stability of the E3 ubiquitin ligase Hrd1 (hydroxymethylglutaryl reductase degradation protein 1), and is necessary for the ERAD activity of the Sel1L-Hrd1 complex. Herein, we showed that Sel1L deficiency specifically in oligodendrocytes caused ERAD impairment, the UPR activation, and attenuation of myelin protein biosynthesis; and resulted in late-onset, progressive myelin thinning in the CNS of adult mice (both male and female). The pancreatic ER kinase (PERK) branch of the UPR functions as the master regulator of protein translation in ER-stressed cells. Importantly, PERK inactivation reversed attenuation of myelin protein biosynthesis in oligodendrocytes and restored myelin thickness in the CNS of oligodendrocyte-specific Sel1L-deficient mice (both male and female). Conversely, blockage of proteolipid protein production exacerbated myelin thinning in the CNS of oligodendrocyte-specific Sel1L-deficient mice (both male and female). These findings suggest that impaired ERAD in oligodendrocytes reduces myelin thickness in the adult CNS through suppression of myelin protein translation by activating PERK.SIGNIFICANCE STATEMENT Myelin is an enormous extended plasma membrane of oligodendrocytes that wraps and insulates axons. Myelin structure, including thickness, was thought to be extraordinarily stable in adults. Myelin proteins, which are produced in the endoplasmic reticulum (ER), are essential and necessary for maintaining myelin structure. The integrated unfolded protein response (UPR) and ER-associated degradation (ERAD) are the primary mechanism that maintains ER protein homeostasis. Herein, we explored the role of the integrated UPR and ERAD in oligodendrocytes in regulating myelin protein production and maintaining myelin structure using mouse models. The results presented in this study imply that the integrated UPR and ERAD in oligodendrocytes maintain myelin thickness in adults by regulating myelin protein production.
Collapse
|
13
|
Yousuf MS, Samtleben S, Lamothe SM, Friedman TN, Catuneanu A, Thorburn K, Desai M, Tenorio G, Schenk GJ, Ballanyi K, Kurata HT, Simmen T, Kerr BJ. Endoplasmic reticulum stress in the dorsal root ganglia regulates large-conductance potassium channels and contributes to pain in a model of multiple sclerosis. FASEB J 2020; 34:12577-12598. [PMID: 32677089 DOI: 10.1096/fj.202001163r] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 06/25/2020] [Accepted: 07/09/2020] [Indexed: 01/22/2023]
Abstract
Neuropathic pain is a common symptom of multiple sclerosis (MS) and current treatment options are ineffective. In this study, we investigated whether endoplasmic reticulum (ER) stress in dorsal root ganglia (DRG) contributes to pain hypersensitivity in the experimental autoimmune encephalomyelitis (EAE) mouse model of MS. Inflammatory cells and increased levels of ER stress markers are evident in post-mortem DRGs from MS patients. Similarly, we observed ER stress in the DRG of mice with EAE and relieving ER stress with a chemical chaperone, 4-phenylbutyric acid (4-PBA), reduced pain hypersensitivity. In vitro, 4-PBA and the selective PERK inhibitor, AMG44, normalize cytosolic Ca2+ transients in putative DRG nociceptors. We went on to assess disease-mediated changes in the functional properties of Ca2+ -sensitive BK-type K+ channels in DRG neurons. We found that the conductance-voltage (GV) relationship of BK channels was shifted to a more positive voltage, together with a more depolarized resting membrane potential in EAE cells. Our results suggest that ER stress in sensory neurons of MS patients and mice with EAE is a source of pain and that ER stress modulators can effectively counteract this phenotype.
Collapse
Affiliation(s)
- Muhammad Saad Yousuf
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| | - Samira Samtleben
- Department of Cell Biology, University of Alberta, Edmonton, AB, Canada
| | - Shawn M Lamothe
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
| | - Timothy N Friedman
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| | - Ana Catuneanu
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
| | - Kevin Thorburn
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
| | - Mansi Desai
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| | - Gustavo Tenorio
- Department of Anesthesiology and Pain Medicine, University of Alberta, Edmonton, AB, Canada
| | - Geert J Schenk
- Department of Anatomy and Neurosciences, Neuroscience Amsterdam, Amsterdam UMC, VU University Medical Center, VUmc MS Center Amsterdam, Amsterdam, The Netherlands
| | - Klaus Ballanyi
- Department of Physiology, University of Alberta, Edmonton, AB, Canada
| | - Harley T Kurata
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada.,Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
| | - Thomas Simmen
- Department of Cell Biology, University of Alberta, Edmonton, AB, Canada
| | - Bradley J Kerr
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada.,Department of Pharmacology, University of Alberta, Edmonton, AB, Canada.,Department of Anesthesiology and Pain Medicine, University of Alberta, Edmonton, AB, Canada
| |
Collapse
|
14
|
NF-κB Activation Accounts for the Cytoprotective Effects of PERK Activation on Oligodendrocytes during EAE. J Neurosci 2020; 40:6444-6456. [PMID: 32661025 DOI: 10.1523/jneurosci.1156-20.2020] [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: 05/12/2020] [Revised: 06/22/2020] [Accepted: 06/30/2020] [Indexed: 01/09/2023] Open
Abstract
Previous studies demonstrate that activation of pancreatic ER kinase (PERK) protects oligodendrocytes against inflammation in the experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis (MS). Interestingly, data indicate that the cytoprotective effects of PERK activation on oligodendrocytes during EAE are not mediated by activating transcription factor 4 (ATF4) but are accompanied by activation of nuclear factor κB (NF-κB). NF-κB plays a critical role in MS and EAE; however, the effects of NF-κB activation on oligodendrocytes in these diseases remain elusive. Herein, we generated a mouse model that allow for activation of NF-κB specifically in oligodendrocytes and found that enhanced NF-κB activation in oligodendrocytes had a minimal effect on their viability and function under normal conditions (both male and female mice). Interestingly, we found that enhanced NF-κB activation in oligodendrocytes attenuated EAE disease severity and ameliorated EAE-induced oligodendrocyte loss, demyelination, and axon degeneration, without affecting inflammation (female mice). Moreover, we showed that the detrimental effects of PERK inactivation in oligodendrocytes in EAE were accompanied by impaired NF-κB activation in oligodendrocytes, and were completely rescued by enhanced NF-κB activation in oligodendrocytes (female mice). These findings suggest that NF-κB activation accounts for the cytoprotective effects of PERK activation on oligodendrocytes in MS and EAE.SIGNIFICANCE STATEMENT Nuclear factor κB (NF-κB) is activated in oligodendrocytes in multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE); however, the role of NF-κB activation in oligodendrocytes in MS and EAE remains elusive. Herein, we generated a mouse model that allows for activation of NF-κB selectively in oligodendrocytes and demonstrated that NF-κB activation prevented oligodendrocyte death and myelin damage in the EAE model. We further demonstrated that NF-κB activation contributed to the protective effects of pancreatic ER kinase (PERK) activation on oligodendrocytes in the EAE model. As such, this work will facilitate the development of new treatments that enhance oligodendrocyte survival in MS patients by targeting the PERK-NF-κB pathway.
Collapse
|
15
|
Stone S, Wu S, Nave KA, Lin W. The UPR preserves mature oligodendrocyte viability and function in adults by regulating autophagy of PLP. JCI Insight 2020; 5:132364. [PMID: 32053121 DOI: 10.1172/jci.insight.132364] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 02/06/2020] [Indexed: 01/03/2023] Open
Abstract
Maintaining cellular proteostasis is essential for oligodendrocyte viability and function; however, its underlying mechanisms remain unexplored. Unfolded protein response (UPR), which comprises 3 parallel branches, inositol requiring enzyme 1 (IRE1), pancreatic ER kinase (PERK), and activating transcription factor 6α (ATF6α), is a major mechanism that maintains cellular proteostasis by facilitating protein folding, attenuating protein translation, and enhancing autophagy and ER-associated degradation. Here we report that impaired UPR in oligodendrocytes via deletion of PERK and ATF6α did not affect developmental myelination but caused late-onset mature oligodendrocyte dysfunction and death in young adult mice. The detrimental effects of the impaired UPR on mature oligodendrocytes were accompanied by autophagy impairment and intracellular proteolipid protein (PLP) accumulation and were rescued by PLP deletion. Data indicate that PLP was degraded by autophagy and that intracellular PLP accumulation was cytotoxic to oligodendrocytes. Thus, these findings imply that the UPR is required for maintaining cellular proteostasis and the viability and function of mature oligodendrocytes in adults by regulating autophagy of PLP.
Collapse
Affiliation(s)
- Sarrabeth Stone
- Department of Neuroscience and.,Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota, USA
| | - Shuangchan Wu
- Department of Neuroscience and.,Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota, USA
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Wensheng Lin
- Department of Neuroscience and.,Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota, USA
| |
Collapse
|
16
|
Jeffries MA, Obr AE, Urbanek K, Fyffe-Maricich SL, Wood TL. Cnp Promoter-Driven Sustained ERK1/2 Activation Increases B-Cell Activation and Suppresses Experimental Autoimmune Encephalomyelitis. ASN Neuro 2020; 12:1759091420971916. [PMID: 33228381 PMCID: PMC7691909 DOI: 10.1177/1759091420971916] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 09/29/2020] [Accepted: 10/09/2020] [Indexed: 01/24/2023] Open
Abstract
The ERK1/2 signaling pathway promotes myelin wrapping during development and remyelination, and sustained ERK1/2 activation in the oligodendrocyte (OL) lineage results in hypermyelination of the CNS. We therefore hypothesized that increased ERK1/2 signaling in the OL lineage would 1) protect against immune-mediated demyelination due to increased baseline myelin thickness and/or 2) promote enhanced remyelination and thus functional recovery after experimental autoimmune encephalomyelitis (EAE) induction. Cnp-Cre;Mek1DD-eGFP/+ mice that express a constitutively active form of MEK1 (the upstream activator of ERK1/2) in the OL lineage, exhibited a significant decrease in EAE clinical severity compared to controls. However, experiments using tamoxifen-inducible Plp-CreERT;Mek1DD-eGFP/+ or Pdgfrα-CreERT;Mek1DD-eGFP mice revealed this was not solely due to a protective or reparative effect resulting from MEK1DD expression specifically in the OL lineage. Because EAE is an immune-mediated disease, we examined Cnp-Cre;Mek1DD-eGFP/+ splenic immune cells for recombination. Surprisingly, GFP+ recombined CD19+ B-cells, CD11b+ monocytes, and CD3+ T-cells were noted when Cre expression was driven by the Cnp promoter. While ERK1/2 signaling in monocytes and T-cells is associated with proinflammatory activation, fewer studies have examined ERK1/2 signaling in B-cell populations. After in vitro stimulation, MEK1DD-expressing B-cells exhibited a 3-fold increase in CD138+ plasmablasts and a 5-fold increase in CD5+CD1dhi B-cells compared to controls. Stimulated MEK1DD-expressing B-cells also exhibited an upregulation of IL-10, known to suppress the initiation of EAE when produced by CD5+CD1dhi regulatory B-cells. Taken together, our data support the conclusion that sustained ERK1/2 activation in B-cells suppresses immune-mediated demyelination via increasing activation of regulatory B10 cells.
Collapse
MESH Headings
- 2',3'-Cyclic Nucleotide 3'-Phosphodiesterase/biosynthesis
- 2',3'-Cyclic Nucleotide 3'-Phosphodiesterase/immunology
- Animals
- B-Lymphocytes/immunology
- B-Lymphocytes/metabolism
- Encephalomyelitis, Autoimmune, Experimental/immunology
- Encephalomyelitis, Autoimmune, Experimental/metabolism
- Encephalomyelitis, Autoimmune, Experimental/prevention & control
- Female
- MAP Kinase Signaling System/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Promoter Regions, Genetic/physiology
Collapse
Affiliation(s)
- Marisa A. Jeffries
- Department of Pharmacology, Physiology, and
Neuroscience, Rutgers University New Jersey Medical School, Newark,
United States
- Center for Neuroscience, University of Pittsburgh,
Pittsburgh, Pennsylvania, United States
- Center for Cell Signaling, Rutgers University New
Jersey Medical School, Newark, United States
| | - Alison E. Obr
- Department of Pharmacology, Physiology, and
Neuroscience, Rutgers University New Jersey Medical School, Newark,
United States
- Center for Cell Signaling, Rutgers University New
Jersey Medical School, Newark, United States
| | - Kelly Urbanek
- Department of Pediatrics, Division of Neurology,
University of Pittsburgh, Pittsburgh, Pennsylvania, United
States
| | - Sharyl L. Fyffe-Maricich
- Center for Neuroscience, University of Pittsburgh,
Pittsburgh, Pennsylvania, United States
- Department of Pediatrics, Division of Neurology,
University of Pittsburgh, Pittsburgh, Pennsylvania, United
States
| | - Teresa L. Wood
- Department of Pharmacology, Physiology, and
Neuroscience, Rutgers University New Jersey Medical School, Newark,
United States
- Center for Cell Signaling, Rutgers University New
Jersey Medical School, Newark, United States
| |
Collapse
|
17
|
Abstract
Activation of the unfolded protein response in response to endoplasmic reticulum stress preserves cell viability and function under stressful conditions. Nevertheless, persistent, unresolvable activation of the unfolded protein response can trigger apoptosis to eliminate stressed cells. Recent studies show that the unfolded protein response plays an important role in the pathogenesis of various disorders of myelin, including multiples sclerosis, Charcot-Marie-Tooth disease, Pelizaeus-Merzbacher disease, vanishing white matter disease, spinal cord injury, tuberous sclerosis complex, and hypoxia-induced perinatal white matter injury. In this review we summarize the current literature on the unfolded protein response and the evidence for its role in the pathogenesis of myelin disorders.
Collapse
Affiliation(s)
- Wensheng Lin
- Department of Neuroscience; Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, USA
| | - Sarrabeth Stone
- Department of Neuroscience; Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, USA
| |
Collapse
|
18
|
Protease Inhibitors, Saquinavir and Darunavir, Inhibit Oligodendrocyte Maturation: Implications for Lysosomal Stress. J Neuroimmune Pharmacol 2019; 16:169-180. [PMID: 31776836 DOI: 10.1007/s11481-019-09893-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 11/06/2019] [Indexed: 12/27/2022]
Abstract
Despite the introduction of antiretroviral (ARV) therapy (ART), approximately 30-50% of people living with human immunodeficiency virus-1 (HIV-1) will develop a spectrum of measurable neurocognitive dysfunction, collectively called HIV-associated neurocognitive disorder (HAND). While the clinical manifestations of HAND have changed with the advent of ART, certain pathological features have endured, including white matter alterations and dysfunction. The persistence of white matter alterations in the post-ART era suggests that ARV drugs themselves may contribute to HAND pathology. Our group has previously demonstrated that two ARV compounds from the protease inhibitor (PI) class, ritonavir and lopinavir, inhibit oligodendrocyte maturation and myelin protein production. We hypothesized that other members of the PI class, saquinavir and darunavir, could also negatively impact oligodendrocyte differentiation. Here we demonstrate that treating primary rat oligodendrocyte precursor cells with therapeutically relevant concentrations of either ARV drug results in a concentration-dependent inhibition of oligodendrocyte maturation in vitro. Furthermore, we show that acidifying endolysosomal pH via a mucolipin transient receptor potential channel 1 (TRPML1) agonist provides protection against saquinavir- and darunavir-induced inhibition of oligodendrocyte maturation. Moreover, our findings suggest, for the first time, an imperative role of proper endolysosomal pH in regulating OL differentation, and that therapeutic targeting of endolysosomes may provide protection against ARV-induced oligodendrocyte dysregulation. Graphical Abstract Treatment of primary rat oligodendrocyte precursor cells with therapeutically relevant concentrations of either antiretroviral compound of the protease inhibitor class, darunavir or saquinavir, results in a concentration-dependent inhibition of oligodendrocyte maturation in vitro. Additionally, in darunavir or saquinavir-treated cultures we observed a concentration-dependent decrease in the number of acidic lysosomes, via immunostaining with LysoTracker Red, compared with vehicle-treated cultures. Finally, we showed that acidifying endolysosomal pH via a mucolipin transient receptor potential channel 1 (TRPML1) agonist provides protection against saquinavir- or darunavir-induced inhibition of oligodendrocyte maturation. Our findings suggest, for the first time, a critical role of proper endolysosomal pH in regulating OL differentation, and that therapeutic targeting of endolysosomes may provide protection against antiretroviral-induced oligodendrocyte dysregulation.
Collapse
|
19
|
Chen Y, Podojil JR, Kunjamma RB, Jones J, Weiner M, Lin W, Miller SD, Popko B. Sephin1, which prolongs the integrated stress response, is a promising therapeutic for multiple sclerosis. Brain 2019; 142:344-361. [PMID: 30657878 DOI: 10.1093/brain/awy322] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 10/23/2018] [Indexed: 12/13/2022] Open
Abstract
Multiple sclerosis is a chronic autoimmune demyelinating disorder of the CNS. Immune-mediated oligodendrocyte cell loss contributes to multiple sclerosis pathogenesis, such that oligodendrocyte-protective strategies represent a promising therapeutic approach. The integrated stress response, which is an innate cellular protective signalling pathway, reduces the cytotoxic impact of inflammation on oligodendrocytes. This response is initiated by phosphorylation of eIF2α to diminish global protein translation and selectively allow for the synthesis of protective proteins. The integrated stress response is terminated by dephosphorylation of eIF2α. The small molecule Sephin1 inhibits eIF2α dephosphorylation, thereby prolonging the protective response. Herein, we tested the effectiveness of Sephin1 in shielding oligodendrocytes against inflammatory stress. We confirmed that Sephin1 prolonged eIF2α phosphorylation in stressed primary oligodendrocyte cultures. Moreover, by using a mouse model of multiple sclerosis, experimental autoimmune encephalomyelitis, we demonstrated that Sephin1 delayed the onset of clinical symptoms, which correlated with a prolonged integrated stress response, reduced oligodendrocyte and axon loss, as well as diminished T cell presence in the CNS. Sephin1 is reportedly a selective inhibitor of GADD34 (PPP1R15A), which is a stress-induced regulatory subunit of protein phosphatase 1 complex that dephosphorylates eIF2α. Consistent with this possibility, GADD34 mutant mice presented with a similar ameliorated experimental autoimmune encephalomyelitis phenotype as Sephin1-treated mice, and Sephin1 did not provide additional therapeutic benefit to the GADD34 mutant animals. Results presented from the adoptive transfer of encephalitogenic T cells between wild-type and GADD34 mutant mice further indicate that the beneficial effects of Sephin1 are mediated through a direct protective effect on the CNS. Of particular therapeutic relevance, Sephin1 provided additive therapeutic benefit when combined with the first line multiple sclerosis drug, interferon β. Together, our results suggest that a neuroprotective treatment based on the enhancement of the integrated stress response would likely have significant therapeutic value for multiple sclerosis patients.
Collapse
Affiliation(s)
- Yanan Chen
- Department of Neurology, The University of Chicago Center for Peripheral Neuropathy, The University of Chicago, Chicago, Illinois, USA
| | - Joseph R Podojil
- Department of Microbiology-Immunology and Interdepartmental Immunobiology Center, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Rejani B Kunjamma
- Department of Neurology, The University of Chicago Center for Peripheral Neuropathy, The University of Chicago, Chicago, Illinois, USA
| | - Joshua Jones
- Department of Neurology, The University of Chicago Center for Peripheral Neuropathy, The University of Chicago, Chicago, Illinois, USA
| | - Molly Weiner
- Department of Neurology, The University of Chicago Center for Peripheral Neuropathy, The University of Chicago, Chicago, Illinois, USA
| | - Wensheng Lin
- Department of Neuroscience, The Institute of Translational Neuroscience, The University of Minnesota, Minneapolis, Minnesota, USA
| | - Stephen D Miller
- Department of Microbiology-Immunology and Interdepartmental Immunobiology Center, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Brian Popko
- Department of Neurology, The University of Chicago Center for Peripheral Neuropathy, The University of Chicago, Chicago, Illinois, USA
| |
Collapse
|
20
|
Yue Y, Stanojlovic M, Lin Y, Karsenty G, Lin W. Oligodendrocyte-specific ATF4 inactivation does not influence the development of EAE. J Neuroinflammation 2019; 16:23. [PMID: 30709400 PMCID: PMC6357515 DOI: 10.1186/s12974-019-1415-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 01/24/2019] [Indexed: 01/13/2023] Open
Abstract
Background Multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE), are inflammatory demyelinating and neurodegenerative diseases of the CNS. Although recent studies suggest the neuroprotective effects of oligodendrocytes in neurodegenerative diseases, it remains unknown whether oligodendrocyte death induced by inflammatory attacks contributes to neurodegeneration in MS and EAE. Upon endoplasmic reticulum (ER) stress, activation of pancreatic ER kinase (PERK) promotes cell survival through induction of activating transcription factor 4 (ATF4) by phosphorylating eukaryotic translation initiation factor 2α (eIF2α). We have generated a mouse model that allows for temporally controlled activation of PERK specifically in oligodendrocytes. Our previous study has demonstrated that PERK activation specifically in oligodendrocytes attenuates EAE disease severity and ameliorates EAE-induced oligodendrocyte apoptosis, demyelination, and axon degeneration, without altering inflammation. Methods We determined whether oligodendrocyte-specific PERK activation reduced neuron loss in the CNS of EAE mice using the mouse model that allows for temporally controlled activation of PERK specifically in oligodendrocytes. We further generated a mouse model that allows for inactivation of ATF4 specifically in oligodendrocytes, and determined the effects of ATF4 inactivation in oligodendrocytes on mice undergoing EAE. Results We showed that protection of oligodendrocytes resulting from PERK activation led to attenuation of neuron loss in the CNS gray matter of EAE mice. Surprisingly, we found that ATF4 inactivation specifically in oligodendrocytes did not alter EAE disease severity and had no effect on oligodendrocyte loss, demyelination, axon degeneration, neuron loss, and inflammation in EAE mice. Conclusions These findings suggest the neuroprotective effects of PERK activation in oligodendrocytes in EAE, and rule out the involvement of ATF4 in oligodendrocytes in the development of EAE. These results imply that the protective effects of PERK activation in oligodendrocytes in MS and EAE are not mediated by ATF4.
Collapse
Affiliation(s)
- Yuan Yue
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA.,Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Milos Stanojlovic
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA.,Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Yifeng Lin
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA.,Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA.,Key Laboratory of Birth Defects, Children's Hospital of Fudan University, Shanghai, 201102, China
| | - Gerard Karsenty
- Department of Genetics and Development, Columbia University Medical Center, New York, NY, 10032, USA
| | - Wensheng Lin
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA. .,Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA.
| |
Collapse
|
21
|
Stone S, Yue Y, Stanojlovic M, Wu S, Karsenty G, Lin W. Neuron-specific PERK inactivation exacerbates neurodegeneration during experimental autoimmune encephalomyelitis. JCI Insight 2019; 4:124232. [PMID: 30674717 DOI: 10.1172/jci.insight.124232] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 12/05/2018] [Indexed: 12/14/2022] Open
Abstract
Multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE), are chronic inflammatory demyelinating and neurodegenerative diseases of the CNS. Although neurodegeneration is the major contributor to chronic disability in MS, mechanisms governing the viability of axons and neurons in MS and EAE remain elusive. Data indicate that activation of pancreatic endoplasmic reticulum kinase (PERK) influences, positively or negatively, neuron and axon viability in various neurodegenerative diseases through induction of ATF4. In this study, we demonstrate that the PERK pathway was activated in neurons during EAE. We found that neuron-specific PERK inactivation impaired EAE resolution and exacerbated EAE-induced axon degeneration, neuron loss, and demyelination. Surprisingly, neuron-specific ATF4 inactivation did not alter EAE disease course or EAE-induced axon degeneration, neuron loss, and demyelination. These results suggest that PERK activation in neurons protects axons and neurons against inflammation in MS and EAE through ATF4-independent mechanisms.
Collapse
Affiliation(s)
- Sarrabeth Stone
- Department of Neuroscience and.,Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota, USA
| | - Yuan Yue
- Department of Neuroscience and.,Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota, USA
| | - Milos Stanojlovic
- Department of Neuroscience and.,Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota, USA
| | - Shuangchan Wu
- Department of Neuroscience and.,Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota, USA
| | - Gerard Karsenty
- Department of Genetics and Development, Columbia University College of Physicians and Surgeons, New York, New York, USA
| | - Wensheng Lin
- Department of Neuroscience and.,Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota, USA
| |
Collapse
|
22
|
LoPresti P. Tau in Oligodendrocytes Takes Neurons in Sickness and in Health. Int J Mol Sci 2018; 19:ijms19082408. [PMID: 30111714 PMCID: PMC6121290 DOI: 10.3390/ijms19082408] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 08/05/2018] [Accepted: 08/06/2018] [Indexed: 12/31/2022] Open
Abstract
Oligodendrocytes (OLGs), the myelin-forming cells of the central nervous system (CNS), are lifelong partners of neurons. They adjust to the functional demands of neurons over the course of a lifetime to meet the functional needs of a healthy CNS. When this functional interplay breaks down, CNS degeneration follows. OLG processes are essential features for OLGs being able to connect with the neurons. As many as fifty cellular processes from a single OLG reach and wrap an equal number of axonal segments. The cellular processes extend to meet and wrap axonal segments with myelin. Further, transport regulation, which is critical for myelination, takes place within the cellular processes. Because the microtubule-associated protein tau plays a crucial role in cellular process extension and myelination, alterations of tau in OLGs have deleterious effects, resulting in neuronal malfunction and CNS degeneration. Here, we review current concepts on the lifelong role of OLGs and myelin for brain health and plasticity. We present key studies of tau in OLGs and select important studies of tau in neurons. The extensive work on tau in neurons has considerably advanced our understanding of how tau promotes either health or disease. Because OLGs are crucial to neuronal health at any age, an understanding of the functions and regulation of tau in OLGs could uncover new therapeutics for selective CNS neurodegenerative diseases.
Collapse
Affiliation(s)
- Patrizia LoPresti
- Department of Psychology, University of Illinois at Chicago, 1007 West Harrison Street, Chicago, IL 60607, USA.
| |
Collapse
|
23
|
Stone S, Wu S, Jamison S, Durose W, Pallais JP, Lin W. Activating transcription factor 6α deficiency exacerbates oligodendrocyte death and myelin damage in immune-mediated demyelinating diseases. Glia 2018; 66:1331-1345. [PMID: 29436030 DOI: 10.1002/glia.23307] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 01/16/2018] [Accepted: 01/29/2018] [Indexed: 01/06/2023]
Abstract
Endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) play a critical role in immune-mediated demyelinating diseases, including multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE), by regulating the viability of oligodendrocytes. Our previous studies show that activation of the PERK branch of the UPR protects myelinating oligodendrocytes against ER stress in young, developing mice that express IFN-γ, a key pro-inflammatory cytokine in MS and EAE, in the CNS. Several studies also demonstrate that PERK activation preserves oligodendrocyte viability and function, protecting mice against EAE. While evidence suggests activation of the ATF6α branch of the UPR in oligodendrocytes under normal and disease conditions, the effects of ATF6α activation on oligodendrocytes in immune-mediated demyelinating diseases remain unknown. Herein, we showed that ATF6α deficiency had no effect on oligodendrocytes under normal conditions. Interestingly, we showed that ATF6α deficiency exacerbated ER stressed-induced myelinating oligodendrocyte death and subsequent myelin loss in the developing CNS of IFN-γ-expressing mice. Moreover, we found that ATF6α deficiency increased EAE severity and aggravated EAE-induced oligodendrocyte loss and demyelination, without affecting inflammation. Thus, these data suggest the protective effects of ATF6α activation on oligodendrocytes in immune-mediated demyelinating diseases.
Collapse
Affiliation(s)
- Sarrabeth Stone
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota.,Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota
| | - Shuangchan Wu
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota.,Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota
| | - Stephanie Jamison
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota.,Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota
| | - Wilaiwan Durose
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota.,Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota
| | - Jean Pierre Pallais
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota.,Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota
| | - Wensheng Lin
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota.,Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota
| |
Collapse
|
24
|
Murao N, Nishitoh H. Role of the unfolded protein response in the development of central nervous system. J Biochem 2017; 162:155-162. [PMID: 28903548 DOI: 10.1093/jb/mvx047] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 05/19/2017] [Indexed: 12/13/2022] Open
Abstract
The unfolded protein response (UPR) is an intracellular homeostatic signalling pathway that is induced by accumulated misfolded/unfolded proteins in the endoplasmic reticulum (ER). The UPR is closely associated with the development of disease in several tissues, including the central nervous system (CNS), in response to ER stress. More recently, the unique features and importance of the UPR have been revealed in neural stem cells (NSCs) and differentiated CNS cells [neurons and glial cells (astrocytes and oligodendrocytes)]. Although several UPR signalling pathways dynamically change in each CNS cell during brain development, the role of UPR signalling in CNS cells (especially NSCs and glial cells) under pathological or physiological conditions is poorly understood. Here, we discuss and summarize the recent progress in understanding how the UPR regulates the proliferation, differentiation, maturation and viability of CNS cells.
Collapse
Affiliation(s)
- Naoya Murao
- Laboratory of Biochemistry and Molecular Biology, Department of Medical Sciences, University of Miyazaki, 5200 Kihara, Miyazaki 889-1692, Japan
| | - Hideki Nishitoh
- Laboratory of Biochemistry and Molecular Biology, Department of Medical Sciences, University of Miyazaki, 5200 Kihara, Miyazaki 889-1692, Japan
| |
Collapse
|
25
|
NF-κB Activation Protects Oligodendrocytes against Inflammation. J Neurosci 2017; 37:9332-9344. [PMID: 28842413 PMCID: PMC5607472 DOI: 10.1523/jneurosci.1608-17.2017] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 08/07/2017] [Accepted: 08/16/2017] [Indexed: 01/13/2023] Open
Abstract
NF-κB is a key player in inflammatory diseases, including multiple sclerosis (MS) and its animal model, experimental autoimmune encephalomyelitis (EAE). However, the effects of NF-κB activation on oligodendrocytes in MS and EAE remain unknown. We generated a mouse model that expresses IκBαΔN, a super-suppressor of NF-κB, specifically in oligodendrocytes and demonstrated that IκBαΔN expression had no effect on oligodendrocytes under normal conditions (both sexes). Interestingly, we showed that oligodendrocyte-specific expression of IκBαΔN blocked NF-κB activation in oligodendrocytes and resulted in exacerbated oligodendrocyte death and hypomyelination in young, developing mice that express IFN-γ ectopically in the CNS (both sexes). We also showed that NF-κB inactivation in oligodendrocytes aggravated IFN-γ-induced remyelinating oligodendrocyte death and remyelination failure in the cuprizone model (male mice). Moreover, we found that NF-κB inactivation in oligodendrocytes increased the susceptibility of mice to EAE (female mice). These findings imply the cytoprotective effects of NF-κB activation on oligodendrocytes in MS and EAE.SIGNIFICANCE STATEMENT Multiple sclerosis (MS) is an inflammatory demyelinating disease of the CNS. NF-κB is a major player in inflammatory diseases that acts by regulating inflammation and cell viability. Data indicate that NF-κB activation in inflammatory cells facilitates the development of MS. However, to date, attempts to understand the role of NF-κB activation in oligodendrocytes in MS have been unsuccessful. Herein, we generated a mouse model that allows for inactivation of NF-κB specifically in oligodendrocytes and then used this model to determine the precise role of NF-κB activation in oligodendrocytes in models of MS. The results presented in this study represent the first demonstration that NF-κB activation acts cell autonomously to protect oligodendrocytes against inflammation in animal models of MS.
Collapse
|
26
|
Clayton BL, Huang A, Kunjamma RB, Solanki A, Popko B. The Integrated Stress Response in Hypoxia-Induced Diffuse White Matter Injury. J Neurosci 2017; 37:7465-7480. [PMID: 28720571 PMCID: PMC5546113 DOI: 10.1523/jneurosci.2738-16.2017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 06/02/2017] [Accepted: 06/25/2017] [Indexed: 12/13/2022] Open
Abstract
Currently no treatments exist for preterm infants with diffuse white matter injury (DWMI) caused by hypoxia. Due to the improved care of preterm neonates and increased recognition by advanced imaging techniques, the prevalence of DWMI is increasing. A better understanding of the pathophysiology of DWMI is therefore of critical importance. The integrated stress response (ISR), a conserved eukaryotic response to myriad stressors including hypoxia, may play a role in hypoxia-induced DWMI and may represent a novel target for much needed therapies. In this study, we use in vitro and in vivo hypoxic models of DWMI to investigate whether the ISR is involved in DWMI. We demonstrate that hypoxia activates the ISR in primary mouse oligodendrocyte precursor cells (OPCs) in vitro and that genetically inhibiting the ISR in differentiating OPCs increases their susceptibility to in vitro hypoxia. We also show that a well established in vivo mild chronic hypoxia (MCH) mouse model and a new severe acute hypoxia (SAH) mouse model of DWMI activates the initial step of the ISR. Nonetheless, genetic inhibition of the ISR has no detectable effect on either MCH- or SAH-induced DWMI. In addition, we demonstrate that genetic enhancement of the ISR does not ameliorate MCH- or SAH-induced DWMI. These studies suggest that, while the ISR protects OPCs from hypoxia in vitro, it does not appear to play a major role in either MCH- or SAH-induced DWMI and is therefore not a likely target for therapies aimed at improving neurological outcome in preterm neonates with hypoxia-induced DWMI.SIGNIFICANCE STATEMENT Diffuse white matter injury (DWMI) caused by hypoxia is a leading cause of neurological deficits following premature birth. An increased understanding of the pathogenesis of this disease is critical. The integrated stress response (ISR) is activated by hypoxia and protects oligodendrocyte lineage cells in other disease models. This has led to an interest in the potential role of the ISR in DWMI. Here we examine the ISR in hypoxia-induced DWMI and show that while the ISR protects oligodendrocyte lineage cells from hypoxia in vitro, genetic inhibition or enhancement of the ISR has no effect on hypoxia-induced DWMI in vivo, suggesting that the ISR does not play a major role in and is not a likely therapeutic target for DWMI.
Collapse
Affiliation(s)
- Benjamin L Clayton
- Department of Neurology, The University of Chicago Center for Peripheral Neuropathy, The University of Chicago, Chicago, Illinois 60637, and
| | - Aaron Huang
- Department of Neurology, The University of Chicago Center for Peripheral Neuropathy, The University of Chicago, Chicago, Illinois 60637, and
| | - Rejani B Kunjamma
- Department of Neurology, The University of Chicago Center for Peripheral Neuropathy, The University of Chicago, Chicago, Illinois 60637, and
| | - Ani Solanki
- Animal Resource Center, The University of Chicago, Chicago, Illinois 60637
| | - Brian Popko
- Department of Neurology, The University of Chicago Center for Peripheral Neuropathy, The University of Chicago, Chicago, Illinois 60637, and
| |
Collapse
|
27
|
Kheitan S, Minuchehr Z, Soheili ZS. Exploring the cross talk between ER stress and inflammation in age-related macular degeneration. PLoS One 2017; 12:e0181667. [PMID: 28742151 PMCID: PMC5524348 DOI: 10.1371/journal.pone.0181667] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 07/05/2017] [Indexed: 12/15/2022] Open
Abstract
Increasing evidence demonstrates that inflammation and endoplasmic reticulum (ER) stress is implicated in the development and progression of age-related macular degeneration (AMD), a multifactorial neurodegenerative disease. However the cross talk between these cellular mechanisms has not been clearly and fully understood. The present study investigates a possible intersection between ER stress and inflammation in AMD. In this study, we recruited two collections of involved protein markers to retrieve their interaction information from IMEx-curated databases, which are the most well- known protein-protein interaction collections, allowing us to design an intersection network for AMD that is unprecedented. In order to find expression activated subnetworks, we utilized AMD expression profiles in our network. In addition, we studied topological characteristics of the most expressed active subnetworks to identify the hubs. With regard to topological quantifications and expressional activity, we reported a list of the most pivotal hubs which are potentially applicable as probable therapeutic targets. Furthermore, we introduced MAPK signaling pathway as a significantly involved pathway in the association between ER stress and inflammation, leading to promising new directions in discovering AMD formation mechanisms and possible treatments.
Collapse
Affiliation(s)
- Samira Kheitan
- Systems Biotechnology Department, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
| | - Zarrin Minuchehr
- Systems Biotechnology Department, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
- * E-mail:
| | - Zahra-Soheila Soheili
- Molecular Medicine Department, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
| |
Collapse
|
28
|
Huang H, Miao L, Liang F, Liu X, Xu L, Teng X, Wang Q, Ridder WH, Shindler KS, Sun Y, Hu Y. Neuroprotection by eIF2α-CHOP inhibition and XBP-1 activation in EAE/optic neuritiss. Cell Death Dis 2017; 8:e2936. [PMID: 28726788 PMCID: PMC5550873 DOI: 10.1038/cddis.2017.329] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 06/05/2017] [Accepted: 06/13/2017] [Indexed: 12/22/2022]
Abstract
No therapies exist to prevent neuronal deficits in multiple sclerosis (MS), because the molecular mechanism responsible for the progressive neurodegeneration is unknown. We previously showed that axon injury-induced neuronal endoplasmic reticulum (ER) stress plays an important role in retinal ganglion cell (RGC) death and optic nerve degeneration in traumatic and glaucomatous optic neuropathies. Optic neuritis, one of the most common clinical manifestations of MS, is readily modeled by experimental autoimmune encephalomyelitis (EAE) in mouse. Using this in vivo model, we now show that ER stress is induced early in EAE and that modulation of ER stress by inhibition of eIF2α-CHOP and activation of XBP-1 in RGC specifically, protects RGC somata and axons and preserves visual function. This finding adds to the evidence that ER stress is a general upstream mechanism for neurodegeneration and suggests that targeting ER stress molecules is a promising therapeutic strategy for neuroprotection in MS.
Collapse
Affiliation(s)
- Haoliang Huang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto CA 94304, USA
| | - Linqing Miao
- Shriners Center for Neural Repair and Rehabilitation, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Feisi Liang
- Shriners Center for Neural Repair and Rehabilitation, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Xiaodong Liu
- Shriners Center for Neural Repair and Rehabilitation, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Lin Xu
- Shriners Center for Neural Repair and Rehabilitation, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Xiuyin Teng
- Shriners Center for Neural Repair and Rehabilitation, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Qizhao Wang
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto CA 94304, USA
| | - William H Ridder
- Southern California College of Optometry, Marshall B. Ketchum University, Fullerton, CA 92831, USA
| | - Kenneth S Shindler
- Scheie Eye Institute and F.M. Kirby Center for Molecular Ophthalmology, Departments of Ophthalmology and Neurology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yang Sun
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto CA 94304, USA
| | - Yang Hu
- Department of Ophthalmology, Stanford University School of Medicine, Palo Alto CA 94304, USA
| |
Collapse
|
29
|
Kanduc D, Shoenfeld Y. From HBV to HPV: Designing vaccines for extensive and intensive vaccination campaigns worldwide. Autoimmun Rev 2016; 15:1054-1061. [DOI: 10.1016/j.autrev.2016.07.030] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Accepted: 07/12/2016] [Indexed: 12/12/2022]
|
30
|
Clayton BLL, Popko B. Endoplasmic reticulum stress and the unfolded protein response in disorders of myelinating glia. Brain Res 2016; 1648:594-602. [PMID: 27055915 PMCID: PMC5036997 DOI: 10.1016/j.brainres.2016.03.046] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 03/25/2016] [Accepted: 03/26/2016] [Indexed: 12/12/2022]
Abstract
Myelin is vital to the proper function of the nervous system. Oligodendrocytes in the CNS and Schwann cells in the PNS are the glial cells responsible for generating the myelin sheath. Myelination requires the production of a vast amount of proteins and lipid-rich membrane, which puts a heavy load on the secretory pathway of myelinating glia and leaves them susceptible to endoplasmic reticulum (ER) stress. Cells respond to ER stress by activating the unfolded protein response (UPR). The UPR is initially protective but in situations of prolonged unresolved stress the UPR can lead to the apoptotic death of the stressed cell. There is strong evidence that ER stress and the UPR play a role in a number of disorders of myelin and myelinating glia, including multiple sclerosis, Pelizaeus-Merzbacher disease, Vanishing White Matter Disease, and Charcot-Marie-Tooth disease. In this review we discuss the role that ER stress and the UPR play in these disorders of myelin. In addition, we discuss the progress that has been made in our understanding of the effect genetic and pharmacological manipulation of the UPR has in mouse models of these disorders and the novel therapeutic potential of targeting the UPR that these studies support. This article is part of a Special Issue entitled SI:ER stress.
Collapse
Affiliation(s)
- Benjamin L L Clayton
- Department of Neurology, The University of Chicago Center for Peripheral Neuropathy, The University of Chicago, IL 60637, United States
| | - Brian Popko
- Department of Neurology, The University of Chicago Center for Peripheral Neuropathy, The University of Chicago, IL 60637, United States.
| |
Collapse
|
31
|
Barrera MJ, Aguilera S, Castro I, Cortés J, Bahamondes V, Quest AFG, Molina C, González S, Hermoso M, Urzúa U, Leyton C, González MJ. Pro-inflammatory cytokines enhance ERAD and ATF6α pathway activity in salivary glands of Sjögren's syndrome patients. J Autoimmun 2016; 75:68-81. [PMID: 27461470 DOI: 10.1016/j.jaut.2016.07.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 06/21/2016] [Accepted: 07/15/2016] [Indexed: 12/12/2022]
Abstract
Salivary gland (SG) acinar-cells are susceptible to endoplasmic reticulum (ER) stress related to their secretory activity and the complexity of synthesized secretory products. SGs of Sjögren's syndrome patients (SS)-patients show signs of inflammation and altered proteostasis, associated with low IRE1α/XBP-1 pathway activity without avert increases in apoptosis. Acinar-cells may avoid apoptosis by activation of the ATF6α pathway and ER-associated protein degradation (ERAD). The aim of this study was to evaluate the role of pro-inflammatory cytokines in ATF6α pathway/ERAD activation and cell viability in labial salivary glands (LSG) of SS-patients. In biopsies from SS-patients increased ATF6α signaling pathway activity, as evidenced by generation of the ATF6f cleavage fragment, and increased expression of ERAD machinery components, such as EDEM1, p97, SEL1L, gp78, UBE2J1, UBE2G2, HERP and DERLIN1, were observed compared to controls. Alternatively, for pro- (active-caspase-3) and anti-apoptotic (cIAP2) markers no significant difference between the two experimental groups was detected. Increased presence of ATF6f and ERAD molecules correlated significantly with increased expression of pro-inflammatory cytokines. These observations were corroborated in vitro in 3D-acini treated with TNF-α and/or IFN-γ, where an increase in the expression and activation of the ATF6α sensor and ERAD machinery components was detected under ER stress conditions, while changes in cell viability and caspase-3 activation were not observed. Cytokine stimulation protected cells from death when co-incubated with an ERAD machinery inhibitor. Alternatively, when cytokines were eliminated from the medium prior to ERAD inhibition, cell death increased, suggesting that the presence of pro-inflammatory cytokines in the medium is essential to maintain cell viability. In conclusion, the ATF6α pathway and the ERAD machinery are active in LSG of SS-patients. Both were also activated by TNF-α and IFN-γ in vitro in 3D-acini and aided in preventing apoptosis. IFN-γ levels were elevated in SS-patients and UPR responses triggered in vitro by this cytokine closely matched those observed in LSG from SS-patients, suggesting that cytokines may induce ER stress.
Collapse
Affiliation(s)
- María-José Barrera
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Sergio Aguilera
- Departamento de Reumatología, Clínica INDISA, Santiago, Chile
| | - Isabel Castro
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Juan Cortés
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Verónica Bahamondes
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Andrew F G Quest
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile; Center for Molecular Studies of the Cell (CEMC), Advanced Center for Chronic Diseases (ACCDiS), Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Claudio Molina
- Escuela Dental, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
| | - Sergio González
- Escuela Dental, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
| | - Marcela Hermoso
- Programa de Inmunología, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Ulises Urzúa
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Cecilia Leyton
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - María-Julieta González
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.
| |
Collapse
|
32
|
Ta HM, Le TM, Ishii H, Takarada-Iemata M, Hattori T, Hashida K, Yamamoto Y, Mori K, Takahashi R, Kitao Y, Hori O. Atf6α deficiency suppresses microglial activation and ameliorates pathology of experimental autoimmune encephalomyelitis. J Neurochem 2016; 139:1124-1137. [PMID: 27333444 DOI: 10.1111/jnc.13714] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Revised: 06/05/2016] [Accepted: 06/06/2016] [Indexed: 12/28/2022]
Abstract
Accumulating evidence suggests a critical role for the unfolded protein response in multiple sclerosis (MS) and in its animal model, experimental autoimmune encephalomyelitis (EAE). In this study, we investigated the relevance of activating transcription factor 6α (ATF6α), an upstream regulator of part of the unfolded protein response, in EAE. The expressions of ATF6α-target molecular chaperones such as glucose-regulated protein 78 (GRP78) and glucose-regulated protein 94 (GRP94) were enhanced in the acute inflammatory phase after induction of EAE. Deletion of Atf6α suppressed the accumulation of T cells and microglia/macrophages in the spinal cord, and ameliorated the clinical course and demyelination after EAE induction. In contrast to the phenotypes in the spinal cord, activation status of T cells in the peripheral tissues or in the culture system was not different between two genotypes. Bone marrow transfer experiments and adoptive transfer of autoimmune CD4+ T cells to recipient mice (passive EAE) also revealed that CNS-resident cells are responsible for the phenotypes observed in Atf6α-/- mice. Further experiments with cultured cells indicated that inflammatory response was reduced in Atf6α-/- microglia, but not in Atf6α-/- astrocytes, and was associated with proteasome-dependent degradation of NF-κB p65. Thus, our results demonstrate a novel role for ATF6α in microglia-mediated CNS inflammation. We investigated the relevance of ATF6α, an upstream regulator of part of the UPR, in EAE. Deletion of Atf6α suppressed inflammation, and ameliorated demyelination after EAE. Bone marrow transfer experiments and adoptive transfer of autoimmune CD4+ T cells revealed that CNS-resident cells are responsible for the phenotypes in Atf6α-/- mice. Furthermore, inflammatory response was reduced in Atf6α-/- microglia, and was associated with degradation of NF-κB p65. Our results demonstrate a novel role for ATF6α in microglia-mediated inflammation. Cover image for this issue: doi: 10.1111/jnc.13346.
Collapse
Affiliation(s)
- Hieu Minh Ta
- Department of Neuroanatomy, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Thuong Manh Le
- Department of Neuroanatomy, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Hiroshi Ishii
- Department of Neuroanatomy, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Mika Takarada-Iemata
- Department of Neuroanatomy, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Tsuyoshi Hattori
- Department of Neuroanatomy, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Koji Hashida
- Department of Neuroanatomy, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Yasuhiko Yamamoto
- Department of Biochemistry and Molecular Vascular Biology, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Kazutoshi Mori
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Ryosuke Takahashi
- Department of Neurology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yasuko Kitao
- Department of Neuroanatomy, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Osamu Hori
- Department of Neuroanatomy, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| |
Collapse
|
33
|
Naughton MC, McMahon JM, FitzGerald UF. The role of the unfolded protein response in myelination. Neural Regen Res 2016; 11:394-5. [PMID: 27127465 PMCID: PMC4828991 DOI: 10.4103/1673-5374.179036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Affiliation(s)
- Michelle C Naughton
- NCBES, Galway Neuroscience Centre, National University of Ireland Galway, Galway City, Republic of Ireland
| | - Jill M McMahon
- NCBES, Galway Neuroscience Centre, National University of Ireland Galway, Galway City, Republic of Ireland
| | - Una F FitzGerald
- NCBES, Galway Neuroscience Centre, National University of Ireland Galway, Galway City, Republic of Ireland
| |
Collapse
|
34
|
Godin JD, Creppe C, Laguesse S, Nguyen L. Emerging Roles for the Unfolded Protein Response in the Developing Nervous System. Trends Neurosci 2016; 39:394-404. [PMID: 27130659 DOI: 10.1016/j.tins.2016.04.002] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 03/23/2016] [Accepted: 04/04/2016] [Indexed: 01/04/2023]
Abstract
The unfolded protein response (UPR) is a homeostatic signaling pathway triggered by protein misfolding in the endoplasmic reticulum (ER). Beyond its protective role, it plays important functions during normal development in response to elevated demand for protein folding. Several UPR effectors show dynamic temporal and spatial expression patterns that correlate with milestones of the central nervous system (CNS) development. Here, we discuss recent studies suggesting that a dynamic regulation of UPR supports generation, maturation, and maintenance of differentiated neurons in the CNS. We further highlight studies supporting a developmental vulnerability of CNS to UPR dysregulation, which underlies neurodevelopmental disorders. We believe that a better understanding of UPR functions may provide novel opportunities for therapeutic strategies to fight ER/UPR-associated human neurological disorders.
Collapse
Affiliation(s)
- Juliette D Godin
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR7104, University of Strasbourg, Illkirch, France.
| | - Catherine Creppe
- GIGA-Neurosciences, University of Liège, C.H.U. Sart Tilman, Liège 4000, Belgium; Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège, C.H.U. Sart Tilman, Liège 4000, Belgium
| | - Sophie Laguesse
- GIGA-Neurosciences, University of Liège, C.H.U. Sart Tilman, Liège 4000, Belgium; Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège, C.H.U. Sart Tilman, Liège 4000, Belgium
| | - Laurent Nguyen
- GIGA-Neurosciences, University of Liège, C.H.U. Sart Tilman, Liège 4000, Belgium; Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège, C.H.U. Sart Tilman, Liège 4000, Belgium; Walloon Excellence in Lifesciences and Biotechnology (WELBIO), University of Liège, C.H.U. Sart Tilman, Liège 4000, Belgium.
| |
Collapse
|
35
|
ER Chaperone BiP/GRP78 Is Required for Myelinating Cell Survival and Provides Protection during Experimental Autoimmune Encephalomyelitis. J Neurosci 2016; 35:15921-33. [PMID: 26631473 DOI: 10.1523/jneurosci.0693-15.2015] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Myelinating cells synthesize large amounts of membrane protein through the secretory pathway, which makes these cells particularly sensitive to perturbations of the endoplasmic reticulum (ER). Ig binding protein (BiP), also known as glucose-regulated protein 78 (GRP78), is a critical ER chaperone that also plays a pivotal role in controlling the cellular response to ER stress. To examine the potential importance of BiP to myelinating cells, we used a conditional knock-out approach to BiP gene inactivation in oligodendrocytes during development, in adulthood, and in response to experimental autoimmune encephalomyelitis (EAE), an animal model of the inflammatory demyelinating disorder multiple sclerosis (MS). During development, mice lacking functional BiP gene expression in oligodendrocytes developed tremors and ataxia and died before reaching maturity. When BiP gene inactivation in oligodendrocytes was initiated in adulthood, the mice displayed severe neurological symptoms including tremors and hind-limb paralysis. The inactivation of BiP in oligodendrocytes during development or in adulthood resulted in oligodendrocyte loss and corresponding severe myelin abnormalities. Mice heterozygous for the oligodendrocyte-specific inactivation of BiP, which were phenotypically normal without evidence of neuropathology, displayed an exacerbated response to EAE that correlated with an increased loss of oligodendrocytes. Furthermore, mice in which the BiP gene was specifically inactivated in developing Schwann cells displayed tremor that progressed to hindlimb paralysis, which correlated with diminished numbers of myelinating Schwann cells and severe PNS hypomyelination. These studies demonstrate that BiP is critical for myelinating cell survival and contributes to the protective response of oligodendrocyte against inflammatory demyelination.
Collapse
|
36
|
Way SW, Popko B. Harnessing the integrated stress response for the treatment of multiple sclerosis. Lancet Neurol 2016; 15:434-43. [PMID: 26873788 PMCID: PMC4792730 DOI: 10.1016/s1474-4422(15)00381-6] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 11/09/2015] [Accepted: 12/02/2015] [Indexed: 12/13/2022]
Abstract
Multiple sclerosis (MS) is a chronic demyelinating autoimmune disease of the central nervous system (CNS) with no known cure. Though a dozen immunomodulatory therapies exist, their impact on progression of disease appears limited. The field has hence focused on alternate strategies for treatment such as enhancing remyelination and CNS repair. Recent progress has been made on a third complimentary treatment approach that involves protecting oligodendrocytes, and the myelin they generate and maintain, from inflammatory-mediated death via enhancement of the integrated stress response (ISR). Studies in cells and mouse models of MS have demonstrated that the ISR, an innate protective pathway that maintains proteostasis, may be effectively harnessed to aid in the protection of oligodendrocytes and myelin during inflammation. With one ISR-modifying drug already in clinical trial and a number of potential future therapies under investigation, this approach may offer an important component in halting the progression of multiple sclerosis.
Collapse
Affiliation(s)
- Sharon W Way
- Department of Neurology, The University of Chicago Center for Peripheral Neuropathy, The University of Chicago, Chicago, IL, USA
| | - Brian Popko
- Department of Neurology, The University of Chicago Center for Peripheral Neuropathy, The University of Chicago, Chicago, IL, USA.
| |
Collapse
|
37
|
Cao SS, Luo KL, Shi L. Endoplasmic Reticulum Stress Interacts With Inflammation in Human Diseases. J Cell Physiol 2016; 231:288-94. [PMID: 26201832 PMCID: PMC4659393 DOI: 10.1002/jcp.25098] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 07/20/2015] [Indexed: 01/28/2023]
Abstract
The endoplasmic reticulum (ER) is a critical organelle for normal cell function and homeostasis. Disturbance in the protein folding process in the ER, termed ER stress, leads to the activation of unfolded protein response (UPR) that encompasses a complex network of intracellular signaling pathways. The UPR can either restore ER homeostasis or activate pro-apoptotic pathways depending on the type of insults, intensity and duration of the stress, and cell types. ER stress and the UPR have recently been linked to inflammation in a variety of human pathologies including autoimmune, infectious, neurodegenerative, and metabolic disorders. In the cell, ER stress and inflammatory signaling share extensive regulators and effectors in a broad spectrum of biological processes. In spite of different etiologies, the two signaling pathways have been shown to form a vicious cycle in exacerbating cellular dysfunction and causing apoptosis in many cells and tissues. However, the interaction between ER stress and inflammation in many of these diseases remains poorly understood. Further understanding of the biochemistry, cell biology, and physiology may enable the development of novel therapies that spontaneously target these pathogenic pathways.
Collapse
Affiliation(s)
- Stewart Siyan Cao
- Columbia University College of Physicians and SurgeonsNew YorkNew York
| | - Katherine L. Luo
- Columbia University College of Physicians and SurgeonsNew YorkNew York
| | - Lynn Shi
- Columbia University College of Physicians and SurgeonsNew YorkNew York
| |
Collapse
|
38
|
Harlow DE, Honce JM, Miravalle AA. Remyelination Therapy in Multiple Sclerosis. Front Neurol 2015; 6:257. [PMID: 26696956 PMCID: PMC4674562 DOI: 10.3389/fneur.2015.00257] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 11/23/2015] [Indexed: 01/10/2023] Open
Abstract
Multiple sclerosis (MS) is an immune-mediated disorder of the central nervous system that results in destruction of the myelin sheath that surrounds axons and eventual neurodegeneration. Current treatments approved for the treatment of relapsing forms of MS target the aberrant immune response and successfully reduce the severity of attacks and frequency of relapses. Therapies are still needed that can repair damage particularly for the treatment of progressive forms of MS for which current therapies are relatively ineffective. Remyelination can restore neuronal function and prevent further neuronal loss and clinical disability. Recent advancements in our understanding of the molecular and cellular mechanisms regulating myelination, as well as the development of high-throughput screens to identify agents that enhance myelination, have lead to the identification of many potential remyelination therapies currently in preclinical and early clinical development. One problem that has plagued the development of treatments to promote remyelination is the difficulty in assessing remyelination in patients with current imaging techniques. Powerful new imaging technologies are making it easier to discern remyelination in patients, which is critical for the assessment of these new therapeutic strategies during clinical trials. This review will summarize what is currently known about remyelination failure in MS, strategies to overcome this failure, new therapeutic treatments in the pipeline for promoting remyelination in MS patients, and new imaging technologies for measuring remyelination in patients.
Collapse
Affiliation(s)
- Danielle E Harlow
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus , Aurora, CO , USA
| | - Justin M Honce
- Department of Radiology, University of Colorado Anschutz Medical Campus , Aurora, CO , USA
| | - Augusto A Miravalle
- Department of Neurology, University of Colorado Anschutz Medical Campus , Aurora, CO , USA
| |
Collapse
|
39
|
Differential activation of ER stress pathways in myelinating cerebellar tracts. Int J Dev Neurosci 2015; 47:347-60. [PMID: 26297908 DOI: 10.1016/j.ijdevneu.2015.08.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 08/12/2015] [Accepted: 08/13/2015] [Indexed: 11/22/2022] Open
Abstract
Myelin production during brain development requires an increase in membrane protein and lipid production in oligodendrocytes and this primarily occurs in the endoplasmic reticulum (ER), an organelle which initiates the Unfolded Protein Response (UPR) when under stress. We hypothesise that the UPR is activated in white matter tracts during myelination in order to expand the ER capacity of oligodendrocytes. Using early and late stage markers, critical myelination time points were identified by immunohistochemistry in developing rat cerebellum. These were correlated to peaks in ER stress signalling by staining for activated UPR transducers (pIRE1, ATF6 and pPERK) and associated downstream molecules (peIF2α, PDI, GRP78, GRP94, CHOP and calreticulin) in cerebellar tracts III and IV. Gene expression in developing cerebellum was assessed by qPCR. Actively myelinating tracts were shown to have differential expression of pIRE1, PERK and ATF6 as well as UPR targets GRP94, GRP78 and PDI. Activated pIRE1-positive cells were widespread at P14 and P17 and at significantly higher numbers during myelination than at other stages. Nuclear-localised ATF6 (indicative of the active transcription factor) peaked at P10, concurrent with the initial phase of myelination. The percentage of cells positive for pPERK was less than 1% at postnatal ages but increased significantly in adult tissue. The downstream targets GRP78, GRP94 and PDI were significantly up-regulated at P17 compared to P7 and remained significantly elevated in adults. The majority of cells positive for these markers and ATF6 were oligodendrocytes as confirmed by dual-labelling. Although gene expression in the cerebellum for GRP78, GRP94 and PDI did not change significantly over time, ATF6 and XBP1s both showed significant fold changes between early and late timepoints. This data helps promote understanding of events occurring during developmental myelination and may have implications for the development of reparative treatments in diseases such as multiple sclerosis.
Collapse
|
40
|
Stone S, Lin W. The unfolded protein response in multiple sclerosis. Front Neurosci 2015; 9:264. [PMID: 26283904 PMCID: PMC4518158 DOI: 10.3389/fnins.2015.00264] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 07/14/2015] [Indexed: 01/08/2023] Open
Abstract
The unfolded protein response (UPR) occurs in response to endoplasmic reticulum (ER) stress caused by the accumulation of unfolded or misfolded proteins in the ER. The UPR is comprised of three signaling pathways that promote cytoprotective functions to correct ER stress; however, if ER stress cannot be resolved the UPR results in apoptosis of affected cells. The UPR is an important feature of various human diseases, including multiple sclerosis (MS). Recent studies have shown several components of the UPR are upregulated in the multiple cell types in MS lesions, including oligodendrocytes, T cells, microglia/macrophages, and astrocytes. Data from animal model studies, particularly studies of experimental autoimmune encephalomyelitis (EAE) and the cuprizone model, imply an important role of the UPR activation in oligodendrocytes in the development of MS. In this review we will cover current literature on the UPR and the evidence for its role in the development of MS.
Collapse
Affiliation(s)
- Sarrabeth Stone
- Department of Neuroscience, University of Minnesota Minneapolis, MN, USA ; Institute for Translational Neuroscience, University of Minnesota Minneapolis, MN, USA
| | - Wensheng Lin
- Department of Neuroscience, University of Minnesota Minneapolis, MN, USA ; Institute for Translational Neuroscience, University of Minnesota Minneapolis, MN, USA
| |
Collapse
|
41
|
The contribution of immune and glial cell types in experimental autoimmune encephalomyelitis and multiple sclerosis. Mult Scler Int 2014; 2014:285245. [PMID: 25374694 PMCID: PMC4211315 DOI: 10.1155/2014/285245] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 09/27/2014] [Accepted: 09/27/2014] [Indexed: 12/19/2022] Open
Abstract
Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system characterised by widespread areas of focal demyelination. Its aetiology and pathogenesis remain unclear despite substantial insights gained through studies of animal models, most notably experimental autoimmune encephalomyelitis (EAE). MS is widely believed to be immune-mediated and pathologically attributable to myelin-specific autoreactive CD4+ T cells. In recent years, MS research has expanded beyond its focus on CD4+ T cells to recognise the contributions of multiple immune and glial cell types to the development, progression, and amelioration of the disease. This review summarises evidence of T and B lymphocyte, natural killer cell, macrophage/microglial, astrocytic, and oligodendroglial involvement in both EAE and MS and the intercommunication and influence of each cell subset in the inflammatory process. Despite important advances in the understanding of the involvement of these cell types in MS, many questions still remain regarding the various subsets within each cell population and their exact contribution to different stages of the disease.
Collapse
|
42
|
Soares MP, Gozzelino R, Weis S. Tissue damage control in disease tolerance. Trends Immunol 2014; 35:483-94. [PMID: 25182198 DOI: 10.1016/j.it.2014.08.001] [Citation(s) in RCA: 132] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 08/09/2014] [Accepted: 08/11/2014] [Indexed: 02/07/2023]
Abstract
Immune-driven resistance mechanisms are the prevailing host defense strategy against infection. By contrast, disease tolerance mechanisms limit disease severity by preventing tissue damage or ameliorating tissue function without interfering with pathogen load. We propose here that tissue damage control underlies many of the protective effects of disease tolerance. We explore the mechanisms of cellular adaptation that underlie tissue damage control in response to infection as well as sterile inflammation, integrating both stress and damage responses. Finally, we discuss the potential impact of targeting these mechanisms in the treatment of disease.
Collapse
|