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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.
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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
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2
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Woo MS, Engler JB, Friese MA. The neuropathobiology of multiple sclerosis. Nat Rev Neurosci 2024; 25:493-513. [PMID: 38789516 DOI: 10.1038/s41583-024-00823-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/30/2024] [Indexed: 05/26/2024]
Abstract
Chronic low-grade inflammation and neuronal deregulation are two components of a smoldering disease activity that drives the progression of disability in people with multiple sclerosis (MS). Although several therapies exist to dampen the acute inflammation that drives MS relapses, therapeutic options to halt chronic disability progression are a major unmet clinical need. The development of such therapies is hindered by our limited understanding of the neuron-intrinsic determinants of resilience or vulnerability to inflammation. In this Review, we provide a neuron-centric overview of recent advances in deciphering neuronal response patterns that drive the pathology of MS. We describe the inflammatory CNS environment that initiates neurotoxicity by imposing ion imbalance, excitotoxicity and oxidative stress, and by direct neuro-immune interactions, which collectively lead to mitochondrial dysfunction and epigenetic dysregulation. The neuronal demise is further amplified by breakdown of neuronal transport, accumulation of cytosolic proteins and activation of cell death pathways. Continuous neuronal damage perpetuates CNS inflammation by activating surrounding glia cells and by directly exerting toxicity on neighbouring neurons. Further, we explore strategies to overcome neuronal deregulation in MS and compile a selection of neuronal actuators shown to impact neurodegeneration in preclinical studies. We conclude by discussing the therapeutic potential of targeting such neuronal actuators in MS, including some that have already been tested in interventional clinical trials.
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Affiliation(s)
- Marcel S Woo
- Institut für Neuroimmunologie und Multiple Sklerose, Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Jan Broder Engler
- Institut für Neuroimmunologie und Multiple Sklerose, Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Manuel A Friese
- Institut für Neuroimmunologie und Multiple Sklerose, Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany.
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Akay-Espinoza C, Newton SEB, Dombroski BA, Kallianpur A, Bharti A, Franklin DR, Schellenberg GD, Heaton RK, Grant I, Ellis RJ, Letendre SL, Jordan-Sciutto KL. Genetic Variations in EIF2AK3 are Associated with Neurocognitive Impairment in People Living with HIV. J Neuroimmune Pharmacol 2024; 19:25. [PMID: 38789639 PMCID: PMC11126443 DOI: 10.1007/s11481-024-10125-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 05/13/2024] [Indexed: 05/26/2024]
Abstract
Based on emerging evidence on the role for specific single-nucleotide variants (SNVs) in EIF2AK3 encoding the integrated stress response kinase PERK, in neurodegeneration, we assessed the association of EIF2AK3 SNVs with neurocognitive performance in people with HIV (PWH) using a candidate gene approach. This retrospective study included the CHARTER cohort participants, excluding those with severe neuropsychiatric comorbidities. Genome-wide data previously obtained for 1047 participants and targeted sequencing of 992 participants with available genomic DNA were utilized to interrogate the association of three noncoding and three coding EIF2AK3 SNVs with the continuous global deficit score (GDS) and global neurocognitive impairment (NCI; GDS ≥ 0.5) using univariable and multivariable methods, with demographic, disease-associated, and treatment characteristics as covariates. The cohort characteristics were as follows: median age, 43.1 years; females, 22.8%; European ancestry, 41%; median CD4 + T cell counts, 175/µL (nadir) and 428/µL (current). At first assessment, 70.5% used ART and 68.3% of these had plasma HIV RNA levels ≤ 200 copies/mL. All three noncoding EIF2AK3 SNVs were associated with GDS and NCI (all p < 0.05). Additionally, 30.9%, 30.9%, and 41.2% of participants had at least one risk allele for the coding SNVs rs1805165 (G), rs867529 (G), and rs13045 (A), respectively. Homozygosity for all three coding SNVs was associated with significantly worse GDS (p < 0.001) and more NCI (p < 0.001). By multivariable analysis, the rs13045 A risk allele, current ART use, and Beck Depression Inventory-II value > 13 were independently associated with GDS and NCI (p < 0.001) whereas the other two coding SNVs did not significantly correlate with GDS or NCI after including rs13045 in the model. The coding EIF2AK3 SNVs were associated with worse performance in executive functioning, motor functioning, learning, and verbal fluency. Coding and non-coding SNVs of EIF2AK3 were associated with global NC and domain-specific performance. The effects were small-to-medium in size but present in multivariable analyses, raising the possibility of specific SNVs in EIF2AK3 as an important component of genetic vulnerability to neurocognitive complications in PWH.
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Affiliation(s)
- Cagla Akay-Espinoza
- Department of Oral Medicine, School of Dental Medicine, University of Pennsylvania, 240 S. 40th St, Rm 312 Levy, Philadelphia, PA, 19104, USA
| | - Sarah E B Newton
- Department of Oral Medicine, School of Dental Medicine, University of Pennsylvania, 240 S. 40th St, Rm 312 Levy, Philadelphia, PA, 19104, USA
| | - Beth A Dombroski
- Department of Pathology and Laboratory Medicine, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Asha Kallianpur
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
- Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Ajay Bharti
- Departments of Medicine, University of California, San Diego, CA, USA
| | - Donald R Franklin
- Department of Psychiatry, University of California, San Diego, CA, USA
| | - Gerard D Schellenberg
- Department of Pathology and Laboratory Medicine, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Robert K Heaton
- Department of Psychiatry, University of California, San Diego, CA, USA
| | - Igor Grant
- Department of Psychiatry, University of California, San Diego, CA, USA
| | - Ronald J Ellis
- Department of Psychiatry, University of California, San Diego, CA, USA
- Department of Neurosciences, University of California, San Diego, CA, USA
| | - Scott L Letendre
- Department of Psychiatry, University of California, San Diego, CA, USA
- Department of Neurosciences, University of California, San Diego, CA, USA
| | - Kelly L Jordan-Sciutto
- Department of Oral Medicine, School of Dental Medicine, University of Pennsylvania, 240 S. 40th St, Rm 312 Levy, Philadelphia, PA, 19104, USA.
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Alkaslasi MR, Lloyd EYH, Gable AS, Silberberg H, Yarur HE, Tsai VS, Tejeda HA, Le Pichon CE. The transcriptional response of cortical neurons to concussion reveals divergent fates after injury. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.26.581939. [PMID: 38463961 PMCID: PMC10925231 DOI: 10.1101/2024.02.26.581939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Traumatic brain injury (TBI) is a risk factor for neurodegeneration, however little is known about how different neuron types respond to this kind of injury. In this study, we follow neuronal populations over several months after a single mild TBI (mTBI) to assess long ranging consequences of injury at the level of single, transcriptionally defined neuronal classes. We find that the stress responsive Activating Transcription Factor 3 (ATF3) defines a population of cortical neurons after mTBI. We show that neurons that activate ATF3 upregulate stress-related genes while repressing many genes, including commonly used markers for these cell types. Using an inducible reporter linked to ATF3, we genetically mark damaged cells to track them over time. Notably, we find that a population in layer V undergoes cell death acutely after injury, while another in layer II/III survives long term and retains the ability to fire action potentials. To investigate the mechanism controlling layer V neuron death, we genetically silenced candidate stress response pathways. We found that the axon injury responsive kinase MAP3K12, also known as dual leucine zipper kinase (DLK), is required for the layer V neuron death. This work provides a rationale for targeting the DLK signaling pathway as a therapeutic intervention for traumatic brain injury. Beyond this, our novel approach to track neurons after a mild, subclinical injury can inform our understanding of neuronal susceptibility to repeated impacts.
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Affiliation(s)
- Mor R. Alkaslasi
- Unit on the Development of Neurodegeneration, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
- Department of Neuroscience, Brown University, Providence, RI, USA
| | - Eliza Y. H. Lloyd
- Unit on the Development of Neurodegeneration, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Austin S. Gable
- Unit on the Development of Neurodegeneration, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Hanna Silberberg
- Unit on the Development of Neurodegeneration, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Hector E. Yarur
- Unit on Neuromodulation and Synaptic Integration, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Valerie S. Tsai
- Unit on Neuromodulation and Synaptic Integration, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Hugo A. Tejeda
- Unit on Neuromodulation and Synaptic Integration, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
| | - Claire E. Le Pichon
- Unit on the Development of Neurodegeneration, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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Lahiri A, Walton JC, Zhang N, Billington N, DeVries AC, Meares GP. Astrocytic deletion of protein kinase R-like ER kinase (PERK) does not affect learning and memory in aged mice but worsens outcome from experimental stroke. J Neurosci Res 2023; 101:1586-1610. [PMID: 37314006 PMCID: PMC10524975 DOI: 10.1002/jnr.25224] [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: 12/10/2022] [Revised: 05/22/2023] [Accepted: 05/27/2023] [Indexed: 06/15/2023]
Abstract
Aging is associated with cognitive decline and is the main risk factor for a myriad of conditions including neurodegeneration and stroke. Concomitant with aging is the progressive accumulation of misfolded proteins and loss of proteostasis. Accumulation of misfolded proteins in the endoplasmic reticulum (ER) leads to ER stress and activation of the unfolded protein response (UPR). The UPR is mediated, in part, by the eukaryotic initiation factor 2α (eIF2α) kinase protein kinase R-like ER kinase (PERK). Phosphorylation of eIF2α reduces protein translation as an adaptive mechanism but this also opposes synaptic plasticity. PERK, and other eIF2α kinases, have been widely studied in neurons where they modulate both cognitive function and response to injury. The impact of astrocytic PERK signaling in cognitive processes was previously unknown. To examine this, we deleted PERK from astrocytes (AstroPERKKO ) and examined the impact on cognitive functions in middle-aged and old mice of both sexes. Additionally, we tested the outcome following experimental stroke using the transient middle cerebral artery occlusion (MCAO) model. Tests of short-term and long-term learning and memory as well as of cognitive flexibility in middle-aged and old mice revealed that astrocytic PERK does not regulate these processes. Following MCAO, AstroPERKKO had increased morbidity and mortality. Collectively, our data demonstrate that astrocytic PERK has limited impact on cognitive function and has a more prominent role in the response to neural injury.
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Affiliation(s)
| | | | | | | | - A Courtney DeVries
- Department of Neuroscience
- Rockefeller Neuroscience Institute
- Department of Medicine, Division of Hematology and Oncology
- WVU Cancer Institute, Morgantown, WV- 26506, USA
- West Virginia Clinical and Translational Science Institute, West Virginia University, Morgantown, WV- 26506, USA
| | - Gordon P. Meares
- Department of Microbiology, Immunology and Cell Biology
- Department of Neuroscience
- Rockefeller Neuroscience Institute
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6
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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.
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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
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7
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Liu P, Karim MR, Covelo A, Yue Y, Lee MK, Lin W. The UPR Maintains Proteostasis and the Viability and Function of Hippocampal Neurons in Adult Mice. Int J Mol Sci 2023; 24:11542. [PMID: 37511300 PMCID: PMC10380539 DOI: 10.3390/ijms241411542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 07/05/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023] Open
Abstract
The unfolded protein response (UPR), which comprises three branches: PERK, ATF6α, and IRE1, is a major mechanism for maintaining cellular proteostasis. Many studies show that the UPR is a major player in regulating neuron viability and function in various neurodegenerative diseases; however, its role in neurodegeneration is highly controversial. Moreover, while evidence suggests activation of the UPR in neurons under normal conditions, deficiency of individual branches of the UPR has no major effect on brain neurons in animals. It remains unclear whether or how the UPR participates in regulating neuronal proteostasis under normal and disease conditions. To determine the physiological role of the UPR in neurons, we generated mice with double deletion of PERK and ATF6α in neurons. We found that inactivation of PERK and ATF6α in neurons caused lysosomal dysfunction (as evidenced by decreased expression of the V0a1 subunit of v-ATPase and decreased activation of cathepsin D), impairment of autophagic flux (as evidenced by increased ratio of LC3-II/LC3-I and increased p62 level), and accumulation of p-tau and Aβ42 in the hippocampus, and led to impairment of spatial memory, impairment of hippocampal LTP, and hippocampal degeneration in adult mice. These results suggest that the UPR is required for maintaining neuronal proteostasis (particularly tau and Aβ homeostasis) and the viability and function of neurons in the hippocampus of adult mice.
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Affiliation(s)
- Pingting Liu
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
- Institute for Translational Neuroscience, University of Minnesota, 2101 6th Street SE, WMBB4-140, Minneapolis, MN 55455, USA
| | - Md Razaul Karim
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
- Institute for Translational Neuroscience, University of Minnesota, 2101 6th Street SE, WMBB4-140, Minneapolis, MN 55455, USA
| | - Ana Covelo
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
| | - Yuan Yue
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
- Institute for Translational Neuroscience, University of Minnesota, 2101 6th Street SE, WMBB4-140, Minneapolis, MN 55455, USA
| | - Michael K Lee
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
- Institute for Translational Neuroscience, University of Minnesota, 2101 6th Street SE, WMBB4-140, Minneapolis, MN 55455, USA
| | - Wensheng Lin
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
- Institute for Translational Neuroscience, University of Minnesota, 2101 6th Street SE, WMBB4-140, Minneapolis, MN 55455, USA
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Gao Y, Wei GZ, Forston MD, Rood B, Hodges ER, Burke D, Andres K, Morehouse J, Armstrong C, Glover C, Slomnicki LP, Ding J, Chariker JH, Rouchka EC, Saraswat Ohri S, Whittemore SR, Hetman M. Opposite modulation of functional recovery following contusive spinal cord injury in mice with oligodendrocyte-selective deletions of Atf4 and Chop/Ddit3. Sci Rep 2023; 13:9193. [PMID: 37280306 PMCID: PMC10244317 DOI: 10.1038/s41598-023-36258-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 05/31/2023] [Indexed: 06/08/2023] Open
Abstract
The integrated stress response (ISR)-activated transcription factors ATF4 and CHOP/DDIT3 may regulate oligodendrocyte (OL) survival, tissue damage and functional impairment/recovery in white matter pathologies, including traumatic spinal cord injury (SCI). Accordingly, in OLs of OL-specific RiboTag mice, Atf4, Chop/Ddit3 and their downstream target gene transcripts were acutely upregulated at 2, but not 10, days post-contusive T9 SCI coinciding with maximal loss of spinal cord tissue. Unexpectedly, another, OL-specific upregulation of Atf4/Chop followed at 42 days post-injury. However, wild type versus OL-specific Atf4-/- or Chop-/- mice showed similar white matter sparing and OL loss at the injury epicenter, as well as unaffected hindlimb function recovery as determined by the Basso mouse scale. In contrast, the horizontal ladder test revealed persistent worsening or improvement of fine locomotor control in OL-Atf4-/- or OL-Chop-/- mice, respectively. Moreover, chronically, OL-Atf-/- mice showed decreased walking speed during plantar stepping despite greater compensatory forelimb usage. Therefore, ATF4 supports, while CHOP antagonizes, fine locomotor control during post-SCI recovery. No correlation between those effects and white matter sparing together with chronic activation of the OL ISR suggest that in OLs, ATF4 and CHOP regulate function of spinal cord circuitries that mediate fine locomotor control during post-SCI recovery.
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Affiliation(s)
- Yonglin Gao
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, 511 S. Floyd St., MDR616, Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, KY, 40292, USA
| | - George Z Wei
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, 511 S. Floyd St., MDR616, Louisville, KY, 40202, USA
- Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY, 40292, USA
- MD/PhD Program, University of Louisville School of Medicine, Louisville, KY, 40292, USA
| | - Michael D Forston
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, 511 S. Floyd St., MDR616, Louisville, KY, 40202, USA
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY, 40292, USA
| | - Benjamin Rood
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, 511 S. Floyd St., MDR616, Louisville, KY, 40202, USA
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY, 40292, USA
| | - Emily R Hodges
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, 511 S. Floyd St., MDR616, Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, KY, 40292, USA
| | - Darlene Burke
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, 511 S. Floyd St., MDR616, Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, KY, 40292, USA
| | - Kariena Andres
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, 511 S. Floyd St., MDR616, Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, KY, 40292, USA
| | - Johnny Morehouse
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, 511 S. Floyd St., MDR616, Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, KY, 40292, USA
| | - Christine Armstrong
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, 511 S. Floyd St., MDR616, Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, KY, 40292, USA
| | - Charles Glover
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, 511 S. Floyd St., MDR616, Louisville, KY, 40202, USA
| | - Lukasz P Slomnicki
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, 511 S. Floyd St., MDR616, Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, KY, 40292, USA
| | - Jixiang Ding
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, 511 S. Floyd St., MDR616, Louisville, KY, 40202, USA
- Department of Oral Immunology and Infectious Diseases, University of Louisville School of Dentistry, Louisville, KY, 40292, USA
| | - Julia H Chariker
- Kentucky Biomedical Research Infrastructure Network Bioinformatics Core, University of Louisville, Louisville, KY, 40292, USA
| | - Eric C Rouchka
- Kentucky Biomedical Research Infrastructure Network Bioinformatics Core, University of Louisville, Louisville, KY, 40292, USA
| | - Sujata Saraswat Ohri
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, 511 S. Floyd St., MDR616, Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, KY, 40292, USA
| | - Scott R Whittemore
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, 511 S. Floyd St., MDR616, Louisville, KY, 40202, USA
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, KY, 40292, USA
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY, 40292, USA
- Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY, 40292, USA
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY, 40292, USA
| | - Michal Hetman
- Kentucky Spinal Cord Injury Research Center, University of Louisville School of Medicine, 511 S. Floyd St., MDR616, Louisville, KY, 40202, USA.
- Department of Neurological Surgery, University of Louisville School of Medicine, Louisville, KY, 40292, USA.
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY, 40292, USA.
- Department of Pharmacology and Toxicology, University of Louisville School of Medicine, Louisville, KY, 40292, USA.
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY, 40292, USA.
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9
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Wu S, Lin W. Endoplasmic reticulum associated degradation is essential for maintaining the viability or function of mature myelinating cells in adults. Glia 2023; 71:1360-1376. [PMID: 36708285 PMCID: PMC10023378 DOI: 10.1002/glia.24346] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 01/11/2023] [Accepted: 01/13/2023] [Indexed: 01/29/2023]
Abstract
Endoplasmic reticulum associated degradation (ERAD) is responsible for recognition and degradation of unfolded or misfolded proteins in the ER. Sel1L is essential for the ERAD activity of Sel1L-Hrd1 complex, the best-known ERAD machinery. Using a continuous Sel1L knockout mouse model (CNP/Cre; Sel1LloxP/loxP mice), our previous studies showed that Sel1L knockout in myelinating cells, oligodendrocytes in the central nervous system (CNS) and Schwann cells in the peripheral nervous system (PNS), leads to adult-onset myelin abnormalities in the CNS and PNS. Because Sel1L is deleted in myelinating cells of CNP/Cre; Sel1LloxP/loxP mice starting at very early stage of differentiation, it is impossible to rule out the possibility that the adult-onset myelin abnormalities in these mice results from developmental myelination defects caused by Sel1L knockout in myelinating cells during development. Thus, using an inducible Sel1L knockout mouse model (PLP/CreERT ; Sel1LloxP/loxP mice) that has normal, intact myelin and myelinating cells in the adult CNS and PNS prior to tamoxifen treatment, we sought to determine if Sel1L knockout in mature myelinating cells of adult mice leads to myelin abnormalities in the CNS and PNS. We showed that Sel1L knockout in mature myelinating cells caused ERAD impairment, ER stress and UPR activation. Interesting, Sel1L knockout in mature oligodendrocytes impaired their myelinating function by suppressing myelin protein translation, and resulted in progressive myelin thinning in the adult CNS. Conversely, Sel1L knockout in mature Schwann cells led to Schwann cell apoptosis and demyelination in the adult PNS. These findings demonstrate the essential roles of ERAD in mature myelinating cells in the adult CNS and PNS under physiological conditions.
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Affiliation(s)
- Shuangchan Wu
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota, United States, 55455
- Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota, United States, 55455
| | - Wensheng Lin
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota, United States, 55455
- Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota, United States, 55455
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10
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Wolzak K, Nölle A, Farina M, Abbink TE, van der Knaap MS, Verhage M, Scheper W. Neuron-specific translational control shift ensures proteostatic resilience during ER stress. EMBO J 2022; 41:e110501. [PMID: 35791631 PMCID: PMC9379547 DOI: 10.15252/embj.2021110501] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 06/06/2022] [Accepted: 06/09/2022] [Indexed: 11/30/2022] Open
Abstract
Proteostasis is essential for cellular survival and particularly important for highly specialised post‐mitotic cells such as neurons. Transient reduction in protein synthesis by protein kinase R‐like endoplasmic reticulum (ER) kinase (PERK)‐mediated phosphorylation of eukaryotic translation initiation factor 2α (p‐eIF2α) is a major proteostatic survival response during ER stress. Paradoxically, neurons are remarkably tolerant to PERK dysfunction, which suggests the existence of cell type‐specific mechanisms that secure proteostatic stress resilience. Here, we demonstrate that PERK‐deficient neurons, unlike other cell types, fully retain the capacity to control translation during ER stress. We observe rescaling of the ATF4 response, while the reduction in protein synthesis is fully retained. We identify two molecular pathways that jointly drive translational control in PERK‐deficient neurons. Haem‐regulated inhibitor (HRI) mediates p‐eIF2α and the ATF4 response and is complemented by the tRNA cleaving RNase angiogenin (ANG) to reduce protein synthesis. Overall, our study elucidates an intricate back‐up mechanism to ascertain translational control during ER stress in neurons that provides a mechanistic explanation for the thus far unresolved observation of neuronal resilience to proteostatic stress.
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Affiliation(s)
- Kimberly Wolzak
- Department of Functional Genomics, Faculty of Science, Center for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit (VU) Amsterdam, Amsterdam, The Netherlands.,Functional Genomics Section, Department of Human Genetics, Amsterdam University Medical Centers (UMC) Location Vrije Universiteit, Amsterdam, The Netherlands
| | - Anna Nölle
- Department of Pathology, Amsterdam University Medical Centers (UMC) Location Vrije Universiteit, Amsterdam, The Netherlands
| | - Margherita Farina
- Department of Functional Genomics, Faculty of Science, Center for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit (VU) Amsterdam, Amsterdam, The Netherlands
| | - Truus Em Abbink
- Department of Child Neurology, Amsterdam University Medical Centers (UMC) Location Vrije Universiteit, Amsterdam, The Netherlands
| | - Marjo S van der Knaap
- Department of Functional Genomics, Faculty of Science, Center for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit (VU) Amsterdam, Amsterdam, The Netherlands.,Department of Child Neurology, Amsterdam University Medical Centers (UMC) Location Vrije Universiteit, Amsterdam, The Netherlands
| | - Matthijs Verhage
- Department of Functional Genomics, Faculty of Science, Center for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit (VU) Amsterdam, Amsterdam, The Netherlands.,Functional Genomics Section, Department of Human Genetics, Amsterdam University Medical Centers (UMC) Location Vrije Universiteit, Amsterdam, The Netherlands
| | - Wiep Scheper
- Department of Functional Genomics, Faculty of Science, Center for Neurogenomics and Cognitive Research (CNCR), Vrije Universiteit (VU) Amsterdam, Amsterdam, The Netherlands.,Functional Genomics Section, Department of Human Genetics, Amsterdam University Medical Centers (UMC) Location Vrije Universiteit, Amsterdam, The Netherlands
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11
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Lei Z, Stone S, Lin W. Detection of PERK Signaling in the Central Nervous System. Methods Mol Biol 2022; 2378:233-245. [PMID: 34985704 DOI: 10.1007/978-1-0716-1732-8_15] [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] [Indexed: 06/14/2023]
Abstract
In response to endoplasmic reticulum (ER) stress, activation of pancreatic ER kinase (PERK) signaling adapts cells to stressful conditions by phosphorylating eukaryotic translation initiation factor 2α (eIF2α). Phosphorylation of eIF2α inhibits global protein translation but stimulates the expression of numerous stress-responsive genes by inducing the transcription factor ATF4. A large number of studies have shown that activation of PERK signaling has beneficial or detrimental effects in various diseases of the central nervous system (CNS), including neurodegenerative diseases, myelin disorders, CNS injuries, among others. This chapter is devoted to describing the practical methods for the detection of PERK signaling in CNS diseases.
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Affiliation(s)
- Zhixin Lei
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, USA
- Institute for Translational Neuroscience, University of Minnesota, 2101 6th Street SE, WMBB4-140, Minneapolis, MN, USA
| | - Sarrabeth Stone
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, USA
- Institute for Translational Neuroscience, University of Minnesota, 2101 6th Street SE, WMBB4-140, Minneapolis, MN, USA
| | - Wensheng Lin
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, USA.
- Institute for Translational Neuroscience, University of Minnesota, 2101 6th Street SE, WMBB4-140, Minneapolis, MN, USA.
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12
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Woo MS, Ufer F, Rothammer N, Di Liberto G, Binkle L, Haferkamp U, Sonner JK, Engler JB, Hornig S, Bauer S, Wagner I, Egervari K, Raber J, Duvoisin RM, Pless O, Merkler D, Friese MA. Neuronal metabotropic glutamate receptor 8 protects against neurodegeneration in CNS inflammation. J Exp Med 2021; 218:e20201290. [PMID: 33661276 PMCID: PMC7938362 DOI: 10.1084/jem.20201290] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Revised: 12/17/2020] [Accepted: 02/02/2021] [Indexed: 12/13/2022] Open
Abstract
Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system with continuous neuronal loss. Treatment of clinical progression remains challenging due to lack of insights into inflammation-induced neurodegenerative pathways. Here, we show that an imbalance in the neuronal receptor interactome is driving glutamate excitotoxicity in neurons of MS patients and identify the MS risk-associated metabotropic glutamate receptor 8 (GRM8) as a decisive modulator. Mechanistically, GRM8 activation counteracted neuronal cAMP accumulation, thereby directly desensitizing the inositol 1,4,5-trisphosphate receptor (IP3R). This profoundly limited glutamate-induced calcium release from the endoplasmic reticulum and subsequent cell death. Notably, we found Grm8-deficient neurons to be more prone to glutamate excitotoxicity, whereas pharmacological activation of GRM8 augmented neuroprotection in mouse and human neurons as well as in a preclinical mouse model of MS. Thus, we demonstrate that GRM8 conveys neuronal resilience to CNS inflammation and is a promising neuroprotective target with broad therapeutic implications.
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Affiliation(s)
- Marcel S. Woo
- Institut für Neuroimmunologie und Multiple Sklerose, Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Friederike Ufer
- Institut für Neuroimmunologie und Multiple Sklerose, Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Nicola Rothammer
- Institut für Neuroimmunologie und Multiple Sklerose, Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Giovanni Di Liberto
- Division of Clinical Pathology, Department of Pathology and Immunology, Geneva Faculty of Medicine, Geneva, Switzerland
| | - Lars Binkle
- Institut für Neuroimmunologie und Multiple Sklerose, Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Undine Haferkamp
- Fraunhofer Institute for Translational Medicine and Pharmacology, Hamburg, Germany
| | - Jana K. Sonner
- Institut für Neuroimmunologie und Multiple Sklerose, Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Jan Broder Engler
- Institut für Neuroimmunologie und Multiple Sklerose, Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Sönke Hornig
- Experimentelle Neuropädiatrie, Klinik für Kinder und Jugendmedizin, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Simone Bauer
- Institut für Neuroimmunologie und Multiple Sklerose, Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Ingrid Wagner
- Division of Clinical Pathology, Department of Pathology and Immunology, Geneva Faculty of Medicine, Geneva, Switzerland
| | - Kristof Egervari
- Division of Clinical Pathology, Department of Pathology and Immunology, Geneva Faculty of Medicine, Geneva, Switzerland
| | - Jacob Raber
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR
- Department of Neurology, Oregon Health & Science University, Portland, OR
- Department of Radiation Medicine, Oregon Health & Science University, Portland, OR
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Portland, OR
| | - Robert M. Duvoisin
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR
| | - Ole Pless
- Fraunhofer Institute for Translational Medicine and Pharmacology, Hamburg, Germany
| | - Doron Merkler
- Division of Clinical Pathology, Department of Pathology and Immunology, Geneva Faculty of Medicine, Geneva, Switzerland
| | - Manuel A. Friese
- Institut für Neuroimmunologie und Multiple Sklerose, Zentrum für Molekulare Neurobiologie Hamburg, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
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13
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Shacham T, Patel C, Lederkremer GZ. PERK Pathway and Neurodegenerative Disease: To Inhibit or to Activate? Biomolecules 2021; 11:biom11030354. [PMID: 33652720 PMCID: PMC7996871 DOI: 10.3390/biom11030354] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/18/2021] [Accepted: 02/23/2021] [Indexed: 12/12/2022] Open
Abstract
With the extension of life span in recent decades, there is an increasing burden of late-onset neurodegenerative diseases, for which effective treatments are lacking. Neurodegenerative diseases include the widespread Alzheimer’s disease (AD) and Parkinson’s disease (PD), the less frequent Huntington’s disease (HD) and Amyotrophic Lateral Sclerosis (ALS) and also rare early-onset diseases linked to mutations that cause protein aggregation or loss of function in genes that maintain protein homeostasis. The difficulties in applying gene therapy approaches to tackle these diseases is drawing increasing attention to strategies that aim to inhibit cellular toxicity and restore homeostasis by intervening in cellular pathways. These include the unfolded protein response (UPR), activated in response to endoplasmic reticulum (ER) stress, a cellular affliction that is shared by these diseases. Special focus is turned to the PKR-like ER kinase (PERK) pathway of the UPR as a target for intervention. However, the complexity of the pathway and its ability to promote cell survival or death, depending on ER stress resolution, has led to some confusion in conflicting studies. Both inhibition and activation of the PERK pathway have been reported to be beneficial in disease models, although there are also some reports where they are counterproductive. Although with the current knowledge a definitive answer cannot be given on whether it is better to activate or to inhibit the pathway, the most encouraging strategies appear to rely on boosting some steps without compromising downstream recovery.
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Affiliation(s)
- Talya Shacham
- Cell Biology Division, George Wise Faculty of Life Sciences, The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Tel Aviv 69978, Israel; (T.S.); (C.P.)
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Chaitanya Patel
- Cell Biology Division, George Wise Faculty of Life Sciences, The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Tel Aviv 69978, Israel; (T.S.); (C.P.)
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Gerardo Z. Lederkremer
- Cell Biology Division, George Wise Faculty of Life Sciences, The Shmunis School of Biomedicine and Cancer Research, Tel Aviv University, Tel Aviv 69978, Israel; (T.S.); (C.P.)
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
- Correspondence: ; Tel.: +972-3-640-9239
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14
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Bond S, Lopez-Lloreda C, Gannon PJ, Akay-Espinoza C, Jordan-Sciutto KL. The Integrated Stress Response and Phosphorylated Eukaryotic Initiation Factor 2α in Neurodegeneration. J Neuropathol Exp Neurol 2020; 79:123-143. [PMID: 31913484 DOI: 10.1093/jnen/nlz129] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 11/07/2019] [Indexed: 02/06/2023] Open
Abstract
The proposed molecular mechanisms underlying neurodegenerative pathogenesis are varied, precluding the development of effective therapies for these increasingly prevalent disorders. One of the most consistent observations across neurodegenerative diseases is the phosphorylation of eukaryotic initiation factor 2α (eIF2α). eIF2α is a translation initiation factor, involved in cap-dependent protein translation, which when phosphorylated causes global translation attenuation. eIF2α phosphorylation is mediated by 4 kinases, which, together with their downstream signaling cascades, constitute the integrated stress response (ISR). While the ISR is activated by stresses commonly observed in neurodegeneration, such as oxidative stress, endoplasmic reticulum stress, and inflammation, it is a canonically adaptive signaling cascade. However, chronic activation of the ISR can contribute to neurodegenerative phenotypes such as neuronal death, memory impairments, and protein aggregation via apoptotic induction and other maladaptive outcomes downstream of phospho-eIF2α-mediated translation inhibition, including neuroinflammation and altered amyloidogenic processing, plausibly in a feed-forward manner. This review examines evidence that dysregulated eIF2a phosphorylation acts as a driver of neurodegeneration, including a survey of observations of ISR signaling in human disease, inspection of the overlap between ISR signaling and neurodegenerative phenomenon, and assessment of recent encouraging findings ameliorating neurodegeneration using developing pharmacological agents which target the ISR. In doing so, gaps in the field, including crosstalk of the ISR kinases and consideration of ISR signaling in nonneuronal central nervous system cell types, are highlighted.
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Affiliation(s)
- Sarah Bond
- From the Department of Biochemistry and Biophysics (SB); Department of Neuroscience (CL-L); Department of Pharmacology (PG), Perelman School of Medicine; Department of Basic and Translational Sciences (CA-E); and Department of Basic and Translational Sciences (KLJ-S), School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Claudia Lopez-Lloreda
- From the Department of Biochemistry and Biophysics (SB); Department of Neuroscience (CL-L); Department of Pharmacology (PG), Perelman School of Medicine; Department of Basic and Translational Sciences (CA-E); and Department of Basic and Translational Sciences (KLJ-S), School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Patrick J Gannon
- From the Department of Biochemistry and Biophysics (SB); Department of Neuroscience (CL-L); Department of Pharmacology (PG), Perelman School of Medicine; Department of Basic and Translational Sciences (CA-E); and Department of Basic and Translational Sciences (KLJ-S), School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Cagla Akay-Espinoza
- From the Department of Biochemistry and Biophysics (SB); Department of Neuroscience (CL-L); Department of Pharmacology (PG), Perelman School of Medicine; Department of Basic and Translational Sciences (CA-E); and Department of Basic and Translational Sciences (KLJ-S), School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Kelly L Jordan-Sciutto
- From the Department of Biochemistry and Biophysics (SB); Department of Neuroscience (CL-L); Department of Pharmacology (PG), Perelman School of Medicine; Department of Basic and Translational Sciences (CA-E); and Department of Basic and Translational Sciences (KLJ-S), School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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15
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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.
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16
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Zhu H, Meissner LE, Byrnes C, Tuymetova G, Tifft CJ, Proia RL. The Complement Regulator Susd4 Influences Nervous-System Function and Neuronal Morphology in Mice. iScience 2020; 23:100957. [PMID: 32179479 PMCID: PMC7075988 DOI: 10.1016/j.isci.2020.100957] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 10/31/2019] [Accepted: 02/25/2020] [Indexed: 01/02/2023] Open
Abstract
The SUSD4 (Sushi domain-containing protein 4) gene encodes a complement inhibitor that is frequently deleted in 1q41q42 microdeletion syndrome, a multisystem congenital disorder that includes neurodevelopmental abnormalities. To understand SUSD4's role in the mammalian nervous system, we analyzed Susd4 knockout (KO) mice. Susd4 KO mice exhibited significant defects in motor performance and significantly higher levels of anxiety-like behaviors. Susd4 KO brain had abnormal “hairy” basket cells surrounding Purkinje neurons within the cerebellum and significantly reduced dendritic spine density in hippocampal pyramidal neurons. Neurons and oligodendrocyte lineage cells of wild-type mice were found to express Susd4 mRNA. Protein expression of the complement component C1q was increased in the brains of Susd4 KO mice. Our data indicate that SUSD4 plays an important role in neuronal functions, possibly via the complement pathway, and that SUSD4 deletion may contribute to the nervous system abnormalities in patients with 1q41q42 deletions. Susd4 is expressed in neurons and oligodendrocyte lineage cells Susd4 knockout mice have abnormal hippocampal and cerebellar neuronal morphologies Susd4 knockout mice exhibit anxiety-like behaviors and impaired motor function Susd4 knockout mice have elevated brain levels of the complement component C1q
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Affiliation(s)
- Hongling Zhu
- Genetics of Development and Disease Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Laura E Meissner
- Office of the Clinical Director and Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Colleen Byrnes
- Genetics of Development and Disease Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Galina Tuymetova
- Genetics of Development and Disease Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Cynthia J Tifft
- Office of the Clinical Director and Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Richard L Proia
- Genetics of Development and Disease Branch, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA.
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17
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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.
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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
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