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Wani KA, Pukkila-Worley R. Evolutionarily ancient functions of enzymatic TIR proteins in innate immunity. Trends Immunol 2025:S1471-4906(25)00116-4. [PMID: 40393889 DOI: 10.1016/j.it.2025.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2025] [Revised: 04/15/2025] [Accepted: 04/22/2025] [Indexed: 05/22/2025]
Abstract
Proteins with a Toll/interleukin-1 receptor/resistance (TIR) domain are among the most ancient immune regulators and include well-known pattern recognition receptors (PRRs). A specialized subset of TIR domain proteins are enzymes that predominantly use nicotinamide adenine dinucleotide (NAD+) to generate second messenger metabolites. These enzymatic TIR proteins have essential roles in bacteria, plant, and animal immunity. The mechanism of activation of these TIR proteins, conserved across Kingdoms, involves oligomerization into higher-ordered structures, which activates their intrinsic enzymatic activity. Here, we review the functions of enzymatic TIR proteins in innate immunity in bacteria, plants, and animals. This work offers insights into the evolutionary origins of immunity itself and defines fundamental principles of immune surveillance across the Tree of Life.
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Affiliation(s)
- Khursheed A Wani
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA.
| | - Read Pukkila-Worley
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA.
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2
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Tse-Kang S, Wani KA, Pukkila-Worley R. Patterns of pathogenesis in innate immunity: insights from C. elegans. Nat Rev Immunol 2025:10.1038/s41577-025-01167-0. [PMID: 40247006 DOI: 10.1038/s41577-025-01167-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/21/2025] [Indexed: 04/19/2025]
Abstract
The cells in barrier tissues can distinguish pathogenic from commensal bacteria and target inflammatory responses only in the context of infection. As such, these cells must be able to identify pathogen infection specifically and not just the presence of an infectious organism, because many innocuous bacteria express the ligands that activate innate immunity in other contexts. Unravelling the mechanisms that underly this specificity, however, is challenging. Free-living nematodes, such as Caenorhabditis elegans, are faced with a similar dilemma, as they live in microorganism-rich habitats and eat bacteria as their source of nutrition. Nematodes lost canonical mechanisms of pattern recognition during their evolution and have instead evolved mechanisms to identify specific ligands or symptoms in the host that indicate active infection with an infectious microorganism. Here we review how C. elegans surveys for these patterns of pathogenesis to activate innate immune defences. Collectively, this work demonstrates that using C. elegans as an experimental platform to study host-pathogen interactions at barrier surfaces reveals primordial and fundamentally important principles of innate immune sensing in the animal branch of the tree of life.
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Affiliation(s)
- Samantha Tse-Kang
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Khursheed A Wani
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Read Pukkila-Worley
- Division of Infectious Diseases and Immunology, Department of Medicine, University of Massachusetts Chan Medical School, Worcester, MA, USA.
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3
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Möller-Ramon Z, Aslani M, Sobczak N, Hristov M, Weber C, Rot A, Duchêne J. The 129 strain-derived passenger mutations in ACKR1-deficient mice alter the expression of PYHIN and Fc-gamma receptor genes. J Leukoc Biol 2025; 117:qiae208. [PMID: 39319406 DOI: 10.1093/jleuko/qiae208] [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: 07/31/2024] [Accepted: 09/24/2024] [Indexed: 09/26/2024] Open
Abstract
Most genetically modified mice have been produced using 129 strain-derived embryonic stem cells. Despite ample backcrosses with other strains, these may retain characteristics for 129 passenger mutations, leading to confounding phenotypes unrelated to targeted genes. Here we show that widely used Ackr1-/-129ES mice have approximately 6 Mb of the 129-derived genome retained adjacently to the Ackr1 locus on chromosome 1, including several characteristic polymorphisms. These most notably affect the expression of PYHIN and Fc-gamma receptor genes in myeloid cells, resulting in the overproduction of IL-1β by activated macrophages and the loss of Fc-gamma receptors on myeloid progenitor cells. Therefore, caution is warranted when interpreting Ackr1-/-129ES mouse phenotypes as being solely due to the ACKR1 deficiency. Our findings call for a careful reevaluation of data from previous studies using Ackr1-/-129ES mice and underscore the limitations and pitfalls inherent to mouse models produced using traditional genetic engineering techniques involving 129 embryonic stem cells.
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Affiliation(s)
- Zoe Möller-Ramon
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians University Munich, Pettenkoferstraße 9, 80336 Munich, Germany
| | - Maria Aslani
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians University Munich, Pettenkoferstraße 9, 80336 Munich, Germany
| | - Nikola Sobczak
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians University Munich, Pettenkoferstraße 9, 80336 Munich, Germany
| | - Michael Hristov
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians University Munich, Pettenkoferstraße 9, 80336 Munich, Germany
| | - Christian Weber
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians University Munich, Pettenkoferstraße 9, 80336 Munich, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Pettenkoferstraße 8a, 80336 Munich, Germany
- Cardiovascular Research Institute Maastricht, University of Maastricht, Universiteitssingel 50, 6229 ER, Maastricht, The Netherlands
| | - Antal Rot
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians University Munich, Pettenkoferstraße 9, 80336 Munich, Germany
- Centre for Microvascular Research, William Harvey Research Institute, Queen Mary University of London, Charterhouse Square, EC1M 6BQ London, United Kingdom
- Centre for Inflammation and Therapeutic Innovation, Queen Mary University of London, Charterhouse Square, EC1M 6BQ London, United Kingdom
| | - Johan Duchêne
- Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians University Munich, Pettenkoferstraße 9, 80336 Munich, Germany
- German Center for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Pettenkoferstraße 8a, 80336 Munich, Germany
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Ye Y, Song F. SARM1 in the pathogenesis of immune-related disease. Toxicol Res (Camb) 2024; 13:tfae208. [PMID: 39664502 PMCID: PMC11631086 DOI: 10.1093/toxres/tfae208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 09/10/2024] [Accepted: 12/02/2024] [Indexed: 12/13/2024] Open
Abstract
Background Sterile alpha and toll interleukin receptor motif-containing protein 1 (SARM1) are primarily expressed in the mammalian nervous system, with their presence in neurons being associated with mitochondrial aggregation. SARM1 functions as a mediator of cell death and morphological changes, while also regulating Waller degeneration in nerve fibers and influencing glial cell formation. Purpose Recent reports demonstrate SARM1 serves as a connector in the Toll-like receptor (TLR) pathway and plays a role in regulating inflammation during periods of stress such as infection, trauma, and hypoxia. These findings offer new insights into pathogenesis research and the prevention and treatment of neurodegenerative diseases and pathogen infections. Methods This review synthesizes recent findings on the immune-related mechanisms of SARM1, emphasizing its roles in inflammation and its functional impact on the nervous system and other bodily systems. Conclusions Understanding the multifaceted roles of SARM1 in immune regulation and neuronal health provides novel insights into its involvement in disease pathogenesis. These insights hold promise for advancing research into the prevention and treatment of neurodegenerative diseases and pathogen-induced conditions.
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Affiliation(s)
- Yihan Ye
- Department of Toxicology and Nutrition, School of Public Health, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan, Shandong 250012, P. R. China
| | - Fuyong Song
- Department of Toxicology and Nutrition, School of Public Health, Cheeloo College of Medicine, Shandong University, 44 West Wenhua Road, Jinan, Shandong 250012, P. R. China
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McGuinness HY, Gu W, Shi Y, Kobe B, Ve T. SARM1-Dependent Axon Degeneration: Nucleotide Signaling, Neurodegenerative Disorders, Toxicity, and Therapeutic Opportunities. Neuroscientist 2024; 30:473-492. [PMID: 37002660 PMCID: PMC11282687 DOI: 10.1177/10738584231162508] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2024]
Abstract
Axons are an essential component of the nervous system, and axon degeneration is an early feature of many neurodegenerative disorders. The NAD+ metabolome plays an essential role in regulating axonal integrity. Axonal levels of NAD+ and its precursor NMN are controlled in large part by the NAD+ synthesizing survival factor NMNAT2 and the pro-neurodegenerative NADase SARM1, whose activation triggers axon destruction. SARM1 has emerged as a promising axon-specific target for therapeutic intervention, and its function, regulation, structure, and role in neurodegenerative diseases have been extensively characterized in recent years. In this review, we first introduce the key molecular players involved in the SARM1-dependent axon degeneration program. Next, we summarize recent major advances in our understanding of how SARM1 is kept inactive in healthy neurons and how it becomes activated in injured or diseased neurons, which has involved important insights from structural biology. Finally, we discuss the role of SARM1 in neurodegenerative disorders and environmental neurotoxicity and its potential as a therapeutic target.
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Affiliation(s)
- Helen Y. McGuinness
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Saint Lucia, Australia
| | - Weixi Gu
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Saint Lucia, Australia
| | - Yun Shi
- Institute for Glycomics, Griffith University, Gold Coast, Australia
| | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, Saint Lucia, Australia
| | - Thomas Ve
- Institute for Glycomics, Griffith University, Gold Coast, Australia
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Fan H, Song C, Zhang J. Sarm1 Controls the MYD88-Mediated Inflammatory Responses in Inflammatory Bowel Disease via the Regulation of TRAF3 Recruitment. Immunol Invest 2024; 53:800-812. [PMID: 38651786 DOI: 10.1080/08820139.2024.2343889] [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] [Indexed: 04/25/2024]
Abstract
BACKGROUND Sterile alpha and TIR motif-containing 1 (Sarm1) is known as a negative regulator of inflammatory responses. However, its role in inflammatory bowel disease (IBD) is still unclear. OBJECTIVE This study aimed to explore the function of Sarm1 in IBD and its underlying mechanisms. Sarm1 and tumor necrosis factor (TNF) receptor associated factor 3 (TRAF3) knockout (KO) micewere established. METHODS The colitis was induced using dextran sulfate sodium (DSS). Bone marrow-derived macrophages (BMDMs) were isolated and stimulated with lipopolysaccharides (LPS) or cytidine phosphate guanosine(CpG). Inflammatory cytokines were measured viaELISA. qPCR and Western blotting were used to determine the levels of the mRNA and protein expression, respectively. RESULTS It was demonstrated that reduced expression of Sarm1 was correlated with the severity of IBD in ulcerative colitis patients, and also with the reduction of pro-inflammatory cytokines in the mouse model induced by DSS. It was further observed that Sarm1 KO enhanced the induction of pro-inflammatory cytokines in both animal and in vitro cell models. Sarm1 deficiency in macrophages increased the severity of colitis in the mouse model induced by DSS. Moreover, Sarm1 regulatedTRAF3 recruitment to myeloid differentiation primary response protein 88 (MyD88), which in turn controlled the MYD88-mediated inflammatory responses. CONCLUSIONS In summary, our data suggest that Sarm1 controls the MYD88-mediated inflammatory responses in IBD via its regulation of TRAF3 recruitment.
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Affiliation(s)
- Huijuan Fan
- Department of Gastroenterology, The Second Affiliated Hospital, Air Force Medical University, Xi'an, Shaanxi, China
| | - Chun Song
- Department of Gastroenterology, The Second Affiliated Hospital, Air Force Medical University, Xi'an, Shaanxi, China
| | - Jingyu Zhang
- Department of Gastroenterology, The Second Affiliated Hospital, Air Force Medical University, Xi'an, Shaanxi, China
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Loreto A, Merlini E, Coleman MP. Programmed axon death: a promising target for treating retinal and optic nerve disorders. Eye (Lond) 2024; 38:1802-1809. [PMID: 38538779 PMCID: PMC11226669 DOI: 10.1038/s41433-024-03025-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 02/13/2024] [Accepted: 03/08/2024] [Indexed: 07/07/2024] Open
Abstract
Programmed axon death is a druggable pathway of axon degeneration that has garnered considerable interest from pharmaceutical companies as a promising therapeutic target for various neurodegenerative disorders. In this review, we highlight mechanisms through which this pathway is activated in the retina and optic nerve, and discuss its potential significance for developing therapies for eye disorders and beyond. At the core of programmed axon death are two enzymes, NMNAT2 and SARM1, with pivotal roles in NAD metabolism. Extensive preclinical data in disease models consistently demonstrate remarkable, and in some instances, complete and enduring neuroprotection when this mechanism is targeted. Findings from animal studies are now being substantiated by genetic human data, propelling the field rapidly toward clinical translation. As we approach the clinical phase, the selection of suitable disorders for initial clinical trials targeting programmed axon death becomes crucial for their success. We delve into the multifaceted roles of programmed axon death and NAD metabolism in retinal and optic nerve disorders. We discuss the role of SARM1 beyond axon degeneration, including its potential involvement in neuronal soma death and photoreceptor degeneration. We also discuss genetic human data and environmental triggers of programmed axon death. Lastly, we touch upon potential therapeutic approaches targeting NMNATs and SARM1, as well as the nicotinamide trials for glaucoma. The extensive literature linking programmed axon death to eye disorders, along with the eye's suitability for drug delivery and visual assessments, makes retinal and optic nerve disorders strong contenders for early clinical trials targeting programmed axon death.
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Affiliation(s)
- Andrea Loreto
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Forvie Site, Robinson Way, Cambridge, UK.
- School of Medical Sciences and Save Sight Institute, Charles Perkins Centre, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.
| | - Elisa Merlini
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Forvie Site, Robinson Way, Cambridge, UK
| | - Michael P Coleman
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Forvie Site, Robinson Way, Cambridge, UK.
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Hinz FI, Villegas CLM, Roberts JT, Yao H, Gaddam S, Delwig A, Green SA, Fredrickson C, Adrian M, Asuncion RR, Cheung TK, Hayne M, Hackos DH, Rose CM, Richmond D, Hoogenraad CC. Context-Specific Stress Causes Compartmentalized SARM1 Activation and Local Degeneration in Cortical Neurons. J Neurosci 2024; 44:e2424232024. [PMID: 38692735 PMCID: PMC11170950 DOI: 10.1523/jneurosci.2424-23.2024] [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: 12/26/2023] [Revised: 04/21/2024] [Accepted: 04/23/2024] [Indexed: 05/03/2024] Open
Abstract
Sterile alpha and TIR motif containing 1 (SARM1) is an inducible NADase that localizes to mitochondria throughout neurons and senses metabolic changes that occur after injury. Minimal proteomic changes are observed upon either SARM1 depletion or activation, suggesting that SARM1 does not exert broad effects on neuronal protein homeostasis. However, whether SARM1 activation occurs throughout the neuron in response to injury and cell stress remains largely unknown. Using a semiautomated imaging pipeline and a custom-built deep learning scoring algorithm, we studied degeneration in both mixed-sex mouse primary cortical neurons and male human-induced pluripotent stem cell-derived cortical neurons in response to a number of different stressors. We show that SARM1 activation is differentially restricted to specific neuronal compartments depending on the stressor. Cortical neurons undergo SARM1-dependent axon degeneration after mechanical transection, and SARM1 activation is limited to the axonal compartment distal to the injury site. However, global SARM1 activation following vacor treatment causes both cell body and axon degeneration. Context-specific stressors, such as microtubule dysfunction and mitochondrial stress, induce axonal SARM1 activation leading to SARM1-dependent axon degeneration and SARM1-independent cell body death. Our data reveal that compartment-specific SARM1-mediated death signaling is dependent on the type of injury and cellular stressor.
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Affiliation(s)
- Flora I Hinz
- Department of Neuroscience, Genentech, Inc., South San Francisco, California 94080
| | | | - Jasmine T Roberts
- Department of Neuroscience, Genentech, Inc., South San Francisco, California 94080
| | - Heming Yao
- Biological Research | AI Development, Genentech, Inc., South San Francisco, California 94080
| | - Shreya Gaddam
- Biological Research | AI Development, Genentech, Inc., South San Francisco, California 94080
| | - Anton Delwig
- Departments of Biochemical and Cellular Pharmacology, Genentech, Inc., South San Francisco, California 94080
| | - Samantha A Green
- Discovery Chemistry, Genentech, Inc., South San Francisco, California 94080
| | - Craig Fredrickson
- Department of Neuroscience, Genentech, Inc., South San Francisco, California 94080
| | - Max Adrian
- Pathology, Genentech, Inc., South San Francisco, California 94080
| | - Raymond R Asuncion
- Transgenic Technology, Genentech, Inc., South San Francisco, California 94080
| | - Tommy K Cheung
- Microchemistry, Proteomics, and Lipidomics, Genentech, Inc., South San Francisco, California 94080
| | - Margaret Hayne
- Department of Neuroscience, Genentech, Inc., South San Francisco, California 94080
| | - David H Hackos
- Department of Neuroscience, Genentech, Inc., South San Francisco, California 94080
| | - Christopher M Rose
- Microchemistry, Proteomics, and Lipidomics, Genentech, Inc., South San Francisco, California 94080
| | - David Richmond
- Biological Research | AI Development, Genentech, Inc., South San Francisco, California 94080
| | - Casper C Hoogenraad
- Department of Neuroscience, Genentech, Inc., South San Francisco, California 94080
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Brazill JM, Shen IR, Craft CS, Magee KL, Park JS, Lorenz M, Strickland A, Wee NK, Zhang X, Beeve AT, Meyer GA, Milbrandt J, DiAntonio A, Scheller EL. Sarm1 knockout prevents type 1 diabetic bone disease in females independent of neuropathy. JCI Insight 2024; 9:e175159. [PMID: 38175722 PMCID: PMC11143934 DOI: 10.1172/jci.insight.175159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 01/03/2024] [Indexed: 01/05/2024] Open
Abstract
Patients with diabetes have a high risk of developing skeletal diseases accompanied by diabetic peripheral neuropathy (DPN). In this study, we isolated the role of DPN in skeletal disease with global and conditional knockout models of sterile-α and TIR-motif-containing protein-1 (Sarm1). SARM1, an NADase highly expressed in the nervous system, regulates axon degeneration upon a range of insults, including DPN. Global knockout of Sarm1 prevented DPN, but not skeletal disease, in male mice with type 1 diabetes (T1D). Female wild-type mice also developed diabetic bone disease but without DPN. Unexpectedly, global Sarm1 knockout completely protected female mice from T1D-associated bone suppression and skeletal fragility despite comparable muscle atrophy and hyperglycemia. Global Sarm1 knockout rescued bone health through sustained osteoblast function with abrogation of local oxidative stress responses. This was independent of the neural actions of SARM1, as beneficial effects on bone were lost with neural conditional Sarm1 knockout. This study demonstrates that the onset of skeletal disease occurs rapidly in both male and female mice with T1D completely independently of DPN. In addition, this reveals that clinical SARM1 inhibitors, currently being developed for treatment of neuropathy, may also have benefits for diabetic bone through actions outside of the nervous system.
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Affiliation(s)
| | - Ivana R. Shen
- Division of Bone and Mineral Diseases, Department of Medicine, and
| | | | | | - Jay S. Park
- Division of Bone and Mineral Diseases, Department of Medicine, and
| | - Madelyn Lorenz
- Division of Bone and Mineral Diseases, Department of Medicine, and
| | - Amy Strickland
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Natalie K. Wee
- Division of Bone and Mineral Diseases, Department of Medicine, and
| | - Xiao Zhang
- Division of Bone and Mineral Diseases, Department of Medicine, and
- Department of Biomedical Engineering, McKelvey School of Engineering, Washington University, St. Louis, Missouri, USA
| | - Alec T. Beeve
- Division of Bone and Mineral Diseases, Department of Medicine, and
- Department of Biomedical Engineering, McKelvey School of Engineering, Washington University, St. Louis, Missouri, USA
| | | | - Jeffrey Milbrandt
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, USA
| | | | - Erica L. Scheller
- Division of Bone and Mineral Diseases, Department of Medicine, and
- Department of Biomedical Engineering, McKelvey School of Engineering, Washington University, St. Louis, Missouri, USA
- Department of Developmental Biology, and
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, USA
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10
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Fazal SV, Mutschler C, Chen CZ, Turmaine M, Chen CY, Hsueh YP, Ibañez-Grau A, Loreto A, Casillas-Bajo A, Cabedo H, Franklin RJM, Barker RA, Monk KR, Steventon BJ, Coleman MP, Gomez-Sanchez JA, Arthur-Farraj P. SARM1 detection in myelinating glia: sarm1/ Sarm1 is dispensable for PNS and CNS myelination in zebrafish and mice. Front Cell Neurosci 2023; 17:1158388. [PMID: 37091921 PMCID: PMC10113485 DOI: 10.3389/fncel.2023.1158388] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 03/14/2023] [Indexed: 04/08/2023] Open
Abstract
Since SARM1 mutations have been identified in human neurological disease, SARM1 inhibition has become an attractive therapeutic strategy to preserve axons in a variety of disorders of the peripheral (PNS) and central nervous system (CNS). While SARM1 has been extensively studied in neurons, it remains unknown whether SARM1 is present and functional in myelinating glia? This is an important question to address. Firstly, to identify whether SARM1 dysfunction in other cell types in the nervous system may contribute to neuropathology in SARM1 dependent diseases? Secondly, to ascertain whether therapies altering SARM1 function may have unintended deleterious impacts on PNS or CNS myelination? Surprisingly, we find that oligodendrocytes express sarm1 mRNA in the zebrafish spinal cord and that SARM1 protein is readily detectable in rodent oligodendrocytes in vitro and in vivo. Furthermore, activation of endogenous SARM1 in cultured oligodendrocytes induces rapid cell death. In contrast, in peripheral glia, SARM1 protein is not detectable in Schwann cells and satellite glia in vivo and sarm1/Sarm1 mRNA is detected at very low levels in Schwann cells, in vivo, in zebrafish and mouse. Application of specific SARM1 activators to cultured mouse Schwann cells does not induce cell death and nicotinamide adenine dinucleotide (NAD) levels remain unaltered suggesting Schwann cells likely contain no functionally relevant levels of SARM1. Finally, we address the question of whether SARM1 is required for myelination or myelin maintenance. In the zebrafish and mouse PNS and CNS, we show that SARM1 is not required for initiation of myelination and myelin sheath maintenance is unaffected in the adult mouse nervous system. Thus, strategies to inhibit SARM1 function to treat neurological disease are unlikely to perturb myelination in humans.
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Affiliation(s)
- Shaline V. Fazal
- Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, United Kingdom
- Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, United Kingdom
| | - Clara Mutschler
- Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, United Kingdom
| | - Civia Z. Chen
- Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, United Kingdom
| | - Mark Turmaine
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Chiung-Ya Chen
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Yi-Ping Hsueh
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Andrea Ibañez-Grau
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández, Alicante, Spain
| | - Andrea Loreto
- Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, United Kingdom
| | - Angeles Casillas-Bajo
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández, Alicante, Spain
- Instituto de Investigación Sanitaria y Biomédica de Alicante (ISABIAL), Alicante, Spain
| | - Hugo Cabedo
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández, Alicante, Spain
- Instituto de Investigación Sanitaria y Biomédica de Alicante (ISABIAL), Alicante, Spain
| | - Robin J. M. Franklin
- Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, United Kingdom
- Altos Labs - Cambridge Institute of Science, Cambridge, United Kingdom
| | - Roger A. Barker
- Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, United Kingdom
- Wellcome-MRC Cambridge Stem Cell Institute, University of Cambridge, Cambridge, United Kingdom
| | - Kelly R. Monk
- Vollum Institute, Oregon Health & Science University, Portland, OR, United States
| | | | - Michael P. Coleman
- Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, United Kingdom
| | - Jose A. Gomez-Sanchez
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández, Alicante, Spain
- Instituto de Investigación Sanitaria y Biomédica de Alicante (ISABIAL), Alicante, Spain
- Millennium Nucleus for the Study of Pain (MiNuSPain), Santiago, Chile
| | - Peter Arthur-Farraj
- Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, United Kingdom
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11
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Traumatic axonopathy in spinal tracts after impact acceleration head injury: Ultrastructural observations and evidence of SARM1-dependent axonal degeneration. Exp Neurol 2023; 359:114252. [PMID: 36244414 DOI: 10.1016/j.expneurol.2022.114252] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 10/05/2022] [Accepted: 10/08/2022] [Indexed: 11/09/2022]
Abstract
Traumatic axonal injury (TAI) and the associated axonopathy are common consequences of traumatic brain injury (TBI) and contribute to significant neurological morbidity. It has been previously suggested that TAI activates a highly conserved program of axonal self-destruction known as Wallerian degeneration (WD). In the present study, we utilize our well-established impact acceleration model of TBI (IA-TBI) to characterize the pathology of injured myelinated axons in the white matter tracks traversing the ventral, lateral, and dorsal spinal columns in the mouse and assess the effect of Sterile Alpha and TIR Motif Containing 1 (Sarm1) gene knockout on acute and subacute axonal degeneration and myelin pathology. In silver-stained preparations, we found that IA-TBI results in white matter pathology as well as terminal field degeneration across the rostrocaudal axis of the spinal cord. At the ultrastructural level, we found that traumatic axonopathy is associated with diverse types of axonal and myelin pathology, ranging from focal axoskeletal perturbations and focal disruption of the myelin sheath to axonal fragmentation. Several morphological features such as neurofilament compaction, accumulation of organelles and inclusions, axoskeletal flocculation, myelin degeneration and formation of ovoids are similar to profiles encountered in classical examples of WD. Other profiles such as excess myelin figures and inner tongue evaginations are more typical of chronic neuropathies. Stereological analysis of pathological axonal and myelin profiles in the ventral, lateral, and dorsal columns of the lower cervical cord (C6) segments from wild type and Sarm1 KO mice at 3 and 7 days post IA-TBI (n = 32) revealed an up to 90% reduction in the density of pathological profiles in Sarm1 KO mice after IA-TBI. Protection was evident across all white matter tracts assessed, but showed some variability. Finally, Sarm1 deletion ameliorated the activation of microglia associated with TAI. Our findings demonstrate the presence of severe traumatic axonopathy in multiple ascending and descending long tracts after IA-TBI with features consistent with some chronic axonopathies and models of WD and the across-tract protective effect of Sarm1 deletion.
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12
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Sarkar A, Kumari N, Mukherjee P. The curious case of SARM1: Dr. Jekyll and Mr. Hyde in cell death and immunity? FEBS J 2023; 290:340-358. [PMID: 34710262 DOI: 10.1111/febs.16256] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 09/21/2021] [Accepted: 10/27/2021] [Indexed: 02/06/2023]
Abstract
Sterile alpha and toll/interleukin-1 receptor motif-containing protein 1 (SARM1) was first identified as a novel ortholog of Drosophila protein CG7915 and was subsequently placed as the fifth member of the human TIR-containing adaptor protein. SARM1 holds a unique position in this family where, unlike other members, it downregulates NFκB activity in response to immunogenic stimulation, interacts with another member of the family, TRIF, to negatively regulate its function, and it also mediates cell death responses. Over the past decade, SARM1 has emerged as one of the primary mediators of programmed axonal degeneration and this robust regulation of axonal degeneration-especially in models of peripheral neuropathy and traumatic injury-makes it an attractive target for therapeutic intervention. The TIR domain of SARM1 possesses an intrinsic NADase activity resulting in cellular energy deficits within the axons, a striking deviation from its other family members of human TLR adaptors. Interestingly, the TIR NADase activity, as seen in SARM1, is also observed in several prokaryotic TIR-containing proteins where they are involved in immune evasion once within the host. Although the immune function of SARM1 is yet to be conclusively discerned, this closeness in function with the prokaryotic TIR-domain containing proteins, places it at an interesting juncture of evolution raising questions about its origin and function in cell death and immunity. In this review, we discuss how a conserved immune adaptor protein like SARM1 switches to a pro-neurodegenerative function and the evolutionarily significance of the process.
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Affiliation(s)
- Ankita Sarkar
- School of Biotechnology, Presidency University, Kolkata, West Bengal, India
| | - Nripa Kumari
- School of Biotechnology, Presidency University, Kolkata, West Bengal, India
| | - Piyali Mukherjee
- School of Biotechnology, Presidency University, Kolkata, West Bengal, India
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13
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Khazma T, Golan-Vaishenker Y, Guez-Haddad J, Grossman A, Sain R, Weitman M, Plotnikov A, Zalk R, Yaron A, Hons M, Opatowsky Y. A duplex structure of SARM1 octamers stabilized by a new inhibitor. Cell Mol Life Sci 2022; 80:16. [PMID: 36564647 PMCID: PMC11072711 DOI: 10.1007/s00018-022-04641-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 11/16/2022] [Accepted: 11/19/2022] [Indexed: 12/25/2022]
Abstract
In recent years, there has been growing interest in SARM1 as a potential breakthrough drug target for treating various pathologies of axon degeneration. SARM1-mediated axon degeneration relies on its TIR domain NADase activity, but recent structural data suggest that the non-catalytic ARM domain could also serve as a pharmacological site as it has an allosteric inhibitory function. Here, we screened for synthetic small molecules that inhibit SARM1, and tested a selected set of these compounds in a DRG axon degeneration assay. Using cryo-EM, we found that one of the newly discovered inhibitors, a calmidazolium designated TK106, not only stabilizes the previously reported inhibited conformation of the octamer, but also a meta-stable structure: a duplex of octamers (16 protomers), which we have now determined to 4.0 Å resolution. In the duplex, each ARM domain protomer is engaged in lateral interactions with neighboring protomers, and is further stabilized by contralateral contacts with the opposing octamer ring. Mutagenesis of the duplex contact sites leads to a moderate increase in SARM1 activation in cultured cells. Based on our data we propose that the duplex assembly constitutes an additional auto-inhibition mechanism that tightly prevents pre-mature activation and axon degeneration.
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Affiliation(s)
- Tami Khazma
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | | | - Julia Guez-Haddad
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Atira Grossman
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Radhika Sain
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Michal Weitman
- Department of Chemistry, Bar-Ilan University, Ramat Gan, Israel
| | - Alexander Plotnikov
- The Nancy and Stephen Grand Israel National Center for Personalized Medicine, Weizmann Institute of Science, Rehovot, Israel
| | - Ran Zalk
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
- Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Avraham Yaron
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Michael Hons
- European Molecular Biology Laboratory, Grenoble, France.
| | - Yarden Opatowsky
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel.
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14
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Bratkowski M, Burdett TC, Danao J, Wang X, Mathur P, Gu W, Beckstead JA, Talreja S, Yang YS, Danko G, Park JH, Walton M, Brown SP, Tegley CM, Joseph PRB, Reynolds CH, Sambashivan S. Uncompetitive, adduct-forming SARM1 inhibitors are neuroprotective in preclinical models of nerve injury and disease. Neuron 2022; 110:3711-3726.e16. [PMID: 36087583 DOI: 10.1016/j.neuron.2022.08.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 07/06/2022] [Accepted: 08/10/2022] [Indexed: 12/15/2022]
Abstract
Axon degeneration is an early pathological event in many neurological diseases. The identification of the nicotinamide adenine dinucleotide (NAD) hydrolase SARM1 as a central metabolic sensor and axon executioner presents an exciting opportunity to develop novel neuroprotective therapies that can prevent or halt the degenerative process, yet limited progress has been made on advancing efficacious inhibitors. We describe a class of NAD-dependent active-site SARM1 inhibitors that function by intercepting NAD hydrolysis and undergoing covalent conjugation with the reaction product adenosine diphosphate ribose (ADPR). The resulting small-molecule ADPR adducts are highly potent and confer compelling neuroprotection in preclinical models of neurological injury and disease, validating this mode of inhibition as a viable therapeutic strategy. Additionally, we show that the most potent inhibitor of CD38, a related NAD hydrolase, also functions by the same mechanism, further underscoring the broader applicability of this mechanism in developing therapies against this class of enzymes.
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Affiliation(s)
| | - Thomas C Burdett
- Biology Department, Nura Bio Inc., South San Francisco, CA 94080, USA
| | - Jean Danao
- Biology Department, Nura Bio Inc., South San Francisco, CA 94080, USA
| | - Xidao Wang
- Biology Department, Nura Bio Inc., South San Francisco, CA 94080, USA
| | - Prakhyat Mathur
- Biology Department, Nura Bio Inc., South San Francisco, CA 94080, USA
| | - Weijing Gu
- Biology Department, Nura Bio Inc., South San Francisco, CA 94080, USA
| | | | - Santosh Talreja
- Biology Department, Nura Bio Inc., South San Francisco, CA 94080, USA
| | - Yu-San Yang
- Biology Department, Nura Bio Inc., South San Francisco, CA 94080, USA
| | - Gregory Danko
- Biology Department, Nura Bio Inc., South San Francisco, CA 94080, USA
| | - Jae Hong Park
- Biology Department, Nura Bio Inc., South San Francisco, CA 94080, USA
| | - Mary Walton
- Chemistry Department, Nura Bio Inc., South San Francisco, CA 94080, USA
| | - Sean P Brown
- Chemistry Department, Nura Bio Inc., South San Francisco, CA 94080, USA
| | | | - Prem Raj B Joseph
- WuXi AppTec, Research Services Division, 6 Cedarbrook Drive, Cranbury, NJ 08512, USA
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15
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Feriotti C, Sá-Pessoa J, Calderón-González R, Gu L, Morris B, Sugisawa R, Insua JL, Carty M, Dumigan A, Ingram RJ, Kissenpfening A, Bowie AG, Bengoechea JA. Klebsiella pneumoniae hijacks the Toll-IL-1R protein SARM1 in a type I IFN-dependent manner to antagonize host immunity. Cell Rep 2022; 40:111167. [PMID: 35947948 PMCID: PMC9638020 DOI: 10.1016/j.celrep.2022.111167] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 05/18/2022] [Accepted: 07/14/2022] [Indexed: 02/06/2023] Open
Abstract
Many bacterial pathogens antagonize host defense responses by translocating effector proteins into cells. It remains an open question how those pathogens not encoding effectors counteract anti-bacterial immunity. Here, we show that Klebsiella pneumoniae exploits the evolutionary conserved innate protein SARM1 to regulate negatively MyD88- and TRIF-governed inflammation, and the activation of the MAP kinases ERK and JNK. SARM1 is required for Klebsiella induction of interleukin-10 (IL-10) by fine-tuning the p38-type I interferon (IFN) axis. SARM1 inhibits the activation of Klebsiella-induced absent in melanoma 2 inflammasome to limit IL-1β production, suppressing further inflammation. Klebsiella exploits type I IFNs to induce SARM1 in a capsule and lipopolysaccharide O-polysaccharide-dependent manner via the TLR4-TRAM-TRIF-IRF3-IFNAR1 pathway. Absence of SARM1 reduces the intracellular survival of K. pneumoniae in macrophages, whereas sarm1-deficient mice control the infection. Altogether, our results illustrate an anti-immunology strategy deployed by a human pathogen. SARM1 inhibition will show a beneficial effect to treat Klebsiella infections.
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Affiliation(s)
- Claudia Feriotti
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast, UK
| | - Joana Sá-Pessoa
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast, UK
| | - Ricardo Calderón-González
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast, UK
| | - Lili Gu
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Brenda Morris
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast, UK
| | - Ryoichi Sugisawa
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Jose L Insua
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast, UK
| | - Michael Carty
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Amy Dumigan
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast, UK
| | - Rebecca J Ingram
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast, UK
| | - Adrien Kissenpfening
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast, UK
| | - Andrew G Bowie
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - José A Bengoechea
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast, UK.
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16
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Hook G, Reinheckel T, Ni J, Wu Z, Kindy M, Peters C, Hook V. Cathepsin B Gene Knockout Improves Behavioral Deficits and Reduces Pathology in Models of Neurologic Disorders. Pharmacol Rev 2022; 74:600-629. [PMID: 35710131 PMCID: PMC9553114 DOI: 10.1124/pharmrev.121.000527] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Cathepsin B (CTSB) is a powerful lysosomal protease. This review evaluated CTSB gene knockout (KO) outcomes for amelioration of brain dysfunctions in neurologic diseases and aging animal models. Deletion of the CTSB gene resulted in significant improvements in behavioral deficits, neuropathology, and/or biomarkers in traumatic brain injury, ischemia, inflammatory pain, opiate tolerance, epilepsy, aging, transgenic Alzheimer's disease (AD), and periodontitis AD models as shown in 12 studies. One study found beneficial effects for double CTSB and cathepsin S KO mice in a multiple sclerosis model. Transgenic AD models using amyloid precursor protein (APP) mimicking common sporadic AD in three studies showed that CTSB KO improved memory, neuropathology, and biomarkers; two studies used APP representing rare familial AD and found no CTSB KO effect, and two studies used highly engineered APP constructs and reported slight increases in a biomarker. In clinical studies, all reports found that CTSB enzyme was upregulated in diverse neurologic disorders, including AD in which elevated CTSB was positively correlated with cognitive dysfunction. In a wide range of neurologic animal models, CTSB was also upregulated and not downregulated. Further, human genetic mutation data provided precedence for CTSB upregulation causing disease. Thus, the consilience of data is that CTSB gene KO results in improved brain dysfunction and reduced pathology through blockade of CTSB enzyme upregulation that causes human neurologic disease phenotypes. The overall findings provide strong support for CTSB as a rational drug target and for CTSB inhibitors as therapeutic candidates for a wide range of neurologic disorders. SIGNIFICANCE STATEMENT: This review provides a comprehensive compilation of the extensive data on the effects of deleting the cathepsin B (CTSB) gene in neurological and aging mouse models of brain disorders. Mice lacking the CTSB gene display improved neurobehavioral deficits, reduced neuropathology, and amelioration of neuronal cell death and inflammatory biomarkers. The significance of the compelling CTSB evidence is that the data consilience validates CTSB as a drug target for discovery of CTSB inhibitors as potential therapeutics for treating numerous neurological diseases.
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Affiliation(s)
- Gregory Hook
- American Life Science Pharmaceuticals, La Jolla, California (G.H.); Institute of Molecular Medicine and Cell Research, Faculty of Medicine, Albert Ludwigs University, Freiburg, Germany (T.R.); German Cancer Consortium (DKTK) Partner Site Freiburg, Freiburg, Germany (T.R.); German Cancer Research Center (DKFZ), Heidelberg, Germany (T.R); Center for Biological Signaling Studies BIOSS, Albert Ludwigs University, Freiburg, Germany (T.R.); Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China (J.N.); Department of Aging Science and Pharmacology, OBT Research Center, Faculty of Dental Science, Kyushu University, Fukuoka, Japan (Z.W); Taneja College of Pharmacy, Department of Pharmaceutical Sciences, University of South Florida, Tampa, Florida (M.K.); James A Haley VAMC, Research Service, Tampa, Florida (M.K.); Institute of Molecular Medicine and Cell Research, Faculty of Biology, Albert Ludwigs University, Freiburg, Germany (C.P.); Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, CA (V.H.); and Department of Neuroscience and Department of Pharmacology, School of Medicine, University of California, La Jolla, CA (V.H.)
| | - Thomas Reinheckel
- American Life Science Pharmaceuticals, La Jolla, California (G.H.); Institute of Molecular Medicine and Cell Research, Faculty of Medicine, Albert Ludwigs University, Freiburg, Germany (T.R.); German Cancer Consortium (DKTK) Partner Site Freiburg, Freiburg, Germany (T.R.); German Cancer Research Center (DKFZ), Heidelberg, Germany (T.R); Center for Biological Signaling Studies BIOSS, Albert Ludwigs University, Freiburg, Germany (T.R.); Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China (J.N.); Department of Aging Science and Pharmacology, OBT Research Center, Faculty of Dental Science, Kyushu University, Fukuoka, Japan (Z.W); Taneja College of Pharmacy, Department of Pharmaceutical Sciences, University of South Florida, Tampa, Florida (M.K.); James A Haley VAMC, Research Service, Tampa, Florida (M.K.); Institute of Molecular Medicine and Cell Research, Faculty of Biology, Albert Ludwigs University, Freiburg, Germany (C.P.); Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, CA (V.H.); and Department of Neuroscience and Department of Pharmacology, School of Medicine, University of California, La Jolla, CA (V.H.)
| | - Junjun Ni
- American Life Science Pharmaceuticals, La Jolla, California (G.H.); Institute of Molecular Medicine and Cell Research, Faculty of Medicine, Albert Ludwigs University, Freiburg, Germany (T.R.); German Cancer Consortium (DKTK) Partner Site Freiburg, Freiburg, Germany (T.R.); German Cancer Research Center (DKFZ), Heidelberg, Germany (T.R); Center for Biological Signaling Studies BIOSS, Albert Ludwigs University, Freiburg, Germany (T.R.); Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China (J.N.); Department of Aging Science and Pharmacology, OBT Research Center, Faculty of Dental Science, Kyushu University, Fukuoka, Japan (Z.W); Taneja College of Pharmacy, Department of Pharmaceutical Sciences, University of South Florida, Tampa, Florida (M.K.); James A Haley VAMC, Research Service, Tampa, Florida (M.K.); Institute of Molecular Medicine and Cell Research, Faculty of Biology, Albert Ludwigs University, Freiburg, Germany (C.P.); Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, CA (V.H.); and Department of Neuroscience and Department of Pharmacology, School of Medicine, University of California, La Jolla, CA (V.H.)
| | - Zhou Wu
- American Life Science Pharmaceuticals, La Jolla, California (G.H.); Institute of Molecular Medicine and Cell Research, Faculty of Medicine, Albert Ludwigs University, Freiburg, Germany (T.R.); German Cancer Consortium (DKTK) Partner Site Freiburg, Freiburg, Germany (T.R.); German Cancer Research Center (DKFZ), Heidelberg, Germany (T.R); Center for Biological Signaling Studies BIOSS, Albert Ludwigs University, Freiburg, Germany (T.R.); Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China (J.N.); Department of Aging Science and Pharmacology, OBT Research Center, Faculty of Dental Science, Kyushu University, Fukuoka, Japan (Z.W); Taneja College of Pharmacy, Department of Pharmaceutical Sciences, University of South Florida, Tampa, Florida (M.K.); James A Haley VAMC, Research Service, Tampa, Florida (M.K.); Institute of Molecular Medicine and Cell Research, Faculty of Biology, Albert Ludwigs University, Freiburg, Germany (C.P.); Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, CA (V.H.); and Department of Neuroscience and Department of Pharmacology, School of Medicine, University of California, La Jolla, CA (V.H.)
| | - Mark Kindy
- American Life Science Pharmaceuticals, La Jolla, California (G.H.); Institute of Molecular Medicine and Cell Research, Faculty of Medicine, Albert Ludwigs University, Freiburg, Germany (T.R.); German Cancer Consortium (DKTK) Partner Site Freiburg, Freiburg, Germany (T.R.); German Cancer Research Center (DKFZ), Heidelberg, Germany (T.R); Center for Biological Signaling Studies BIOSS, Albert Ludwigs University, Freiburg, Germany (T.R.); Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China (J.N.); Department of Aging Science and Pharmacology, OBT Research Center, Faculty of Dental Science, Kyushu University, Fukuoka, Japan (Z.W); Taneja College of Pharmacy, Department of Pharmaceutical Sciences, University of South Florida, Tampa, Florida (M.K.); James A Haley VAMC, Research Service, Tampa, Florida (M.K.); Institute of Molecular Medicine and Cell Research, Faculty of Biology, Albert Ludwigs University, Freiburg, Germany (C.P.); Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, CA (V.H.); and Department of Neuroscience and Department of Pharmacology, School of Medicine, University of California, La Jolla, CA (V.H.)
| | - Christoph Peters
- American Life Science Pharmaceuticals, La Jolla, California (G.H.); Institute of Molecular Medicine and Cell Research, Faculty of Medicine, Albert Ludwigs University, Freiburg, Germany (T.R.); German Cancer Consortium (DKTK) Partner Site Freiburg, Freiburg, Germany (T.R.); German Cancer Research Center (DKFZ), Heidelberg, Germany (T.R); Center for Biological Signaling Studies BIOSS, Albert Ludwigs University, Freiburg, Germany (T.R.); Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China (J.N.); Department of Aging Science and Pharmacology, OBT Research Center, Faculty of Dental Science, Kyushu University, Fukuoka, Japan (Z.W); Taneja College of Pharmacy, Department of Pharmaceutical Sciences, University of South Florida, Tampa, Florida (M.K.); James A Haley VAMC, Research Service, Tampa, Florida (M.K.); Institute of Molecular Medicine and Cell Research, Faculty of Biology, Albert Ludwigs University, Freiburg, Germany (C.P.); Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, CA (V.H.); and Department of Neuroscience and Department of Pharmacology, School of Medicine, University of California, La Jolla, CA (V.H.)
| | - Vivian Hook
- American Life Science Pharmaceuticals, La Jolla, California (G.H.); Institute of Molecular Medicine and Cell Research, Faculty of Medicine, Albert Ludwigs University, Freiburg, Germany (T.R.); German Cancer Consortium (DKTK) Partner Site Freiburg, Freiburg, Germany (T.R.); German Cancer Research Center (DKFZ), Heidelberg, Germany (T.R); Center for Biological Signaling Studies BIOSS, Albert Ludwigs University, Freiburg, Germany (T.R.); Key Laboratory of Molecular Medicine and Biotherapy, Department of Biology, School of Life Science, Beijing Institute of Technology, Beijing, China (J.N.); Department of Aging Science and Pharmacology, OBT Research Center, Faculty of Dental Science, Kyushu University, Fukuoka, Japan (Z.W); Taneja College of Pharmacy, Department of Pharmaceutical Sciences, University of South Florida, Tampa, Florida (M.K.); James A Haley VAMC, Research Service, Tampa, Florida (M.K.); Institute of Molecular Medicine and Cell Research, Faculty of Biology, Albert Ludwigs University, Freiburg, Germany (C.P.); Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, CA (V.H.); and Department of Neuroscience and Department of Pharmacology, School of Medicine, University of California, La Jolla, CA (V.H.)
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17
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Ward A, Jessop F, Faris R, Shoup D, Bosio CM, Peterson KE, Priola SA. Lack of the immune adaptor molecule SARM1 accelerates disease in prion infected mice and is associated with increased mitochondrial respiration and decreased expression of NRF2. PLoS One 2022; 17:e0267720. [PMID: 35507602 PMCID: PMC9067904 DOI: 10.1371/journal.pone.0267720] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 04/13/2022] [Indexed: 11/18/2022] Open
Abstract
Prion diseases are a group of fatal, transmissible neurodegenerative diseases of mammals. In the brain, axonal loss and neuronal death are prominent in prion infection, but the mechanisms remain poorly understood. Sterile alpha and heat/Armadillo motif 1 (SARM1) is a protein expressed in neurons of the brain that plays a critical role in axonal degeneration. Following damage to axons, it acquires an NADase activity that helps to regulate mitochondrial health by breaking down NAD+, a molecule critical for mitochondrial respiration. SARM1 has been proposed to have a protective effect in prion disease, and we hypothesized that it its role in regulating mitochondrial energetics may be involved. We therefore analyzed mitochondrial respiration in SARM1 knockout mice (SARM1KO) and wild-type mice inoculated either with prions or normal brain homogenate. Pathologically, disease was similar in both strains of mice, suggesting that SARM1 mediated axonal degradation is not the sole mechanism of axonal loss during prion disease. However, mitochondrial respiration was significantly increased and disease incubation time accelerated in prion infected SARM1KO mice when compared to wild-type mice. Increased levels of mitochondrial complexes II and IV and decreased levels of NRF2, a potent regulator of reactive oxygen species, were also apparent in the brains of SARM1KO mice when compared to wild-type mice. Our data suggest that SARM1 slows prion disease progression, likely by regulating mitochondrial respiration, which may help to mitigate oxidative stress via NRF2.
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Affiliation(s)
- Anne Ward
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana, United States of America
| | - Forrest Jessop
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana, United States of America
| | - Robert Faris
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Daniel Shoup
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana, United States of America
| | - Catharine M. Bosio
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana, United States of America
| | - Karin E. Peterson
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana, United States of America
| | - Suzette A. Priola
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, Hamilton, Montana, United States of America
- * E-mail:
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18
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Cao Y, Wang Y, Yang J. NAD +-dependent mechanism of pathological axon degeneration. CELL INSIGHT 2022; 1:100019. [PMID: 37193131 PMCID: PMC10120281 DOI: 10.1016/j.cellin.2022.100019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/01/2022] [Accepted: 03/02/2022] [Indexed: 05/18/2023]
Abstract
Pathological axon degeneration is broadly observed in neurodegenerative diseases. This unique process of axonal pathology could directly interfere with the normal functions of neurocircuitries and contribute to the onset of clinical symptoms in patients. It has been increasingly recognized that functional preservation of axonal structures is an indispensable part of therapeutic strategies for treating neurological disorders. In the past decades, the research field has witnessed significant breakthroughs in understanding the stereotyped self-destruction of axons upon neurodegenerative insults, which is distinct from all the known types of programmed cell death. In particular, the novel NAD+-dependent mechanism involving the WLDs, NMNAT2, and SARM1 proteins has emerged. This review summarizes the landmark discoveries elucidating the molecular pathway of pathological axon degeneration and highlights the evolving concept that neurodegeneration would be intrinsically linked to NAD+ and energy metabolism.
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Affiliation(s)
- Ying Cao
- Center for Life Sciences, Peking University, Beijing, 100871, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Yi Wang
- Center for Life Sciences, Peking University, Beijing, 100871, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Jing Yang
- Center for Life Sciences, Peking University, Beijing, 100871, China
- State Key Laboratory of Membrane Biology, School of Life Sciences, Peking University, Beijing, 100871, China
- IDG/McGovern Institute for Brain Research, Peking University, Beijing, 100871, China
- Chinese Institute for Brain Research, Beijing, 102206, China
- Institute of Molecular Physiology, Shenzhen Bay Laboratory, Shenzhen, 518055, China
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19
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Gibbons L, Ozaki E, Greene C, Trappe A, Carty M, Coppinger JA, Bowie AG, Campbell M, Doyle SL. SARM1 Promotes Photoreceptor Degeneration in an Oxidative Stress Model of Retinal Degeneration. Front Neurosci 2022; 16:852114. [PMID: 35431772 PMCID: PMC9012108 DOI: 10.3389/fnins.2022.852114] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 03/04/2022] [Indexed: 11/13/2022] Open
Abstract
SARM1 (sterile alpha and armadillo motif-containing protein) is a highly conserved Toll/IL-1 Receptor (TIR) adaptor with important roles in mediating immune responses. Studies in the brain have shown that SARM1 plays a role in induction of neuronal axon degeneration in response to a variety of injuries. We recently demonstrated that SARM1 is pro-degenerative in a genetic model of inherited retinopathy. This current study aimed to characterise the effect of SARM1 deletion in an alternative model of retinal degeneration (RD) in which the retinal pigment epithelium (RPE) fragments following administration of oxidising agent, sodium iodate (NaIO3), leading to subsequent photoreceptor cell death. Following administration of NaIO3, we observed no apparent difference in rate of loss of RPE integrity in SARM1 deficient mice compared to WT counterparts. However, despite no differences in RPE degeneration, photoreceptor cell number and retinal thickness were increased in Sarm1–/– mice compared to WT counterparts. This apparent protection of the photoreceptors in SARM1 deficient mice is supported by an observed decrease in pro-apoptotic caspase-3 in the photoreceptor layer of Sarm1–/– mice compared to WT. Together these data indicate a pro-degenerative role for SARM1 in the photoreceptors, but not in the RPE, in an oxidative stress induced model of retinal degeneration consistent with its known degenerative role in neurons in a range of neurodegenerative settings.
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Affiliation(s)
- Luke Gibbons
- Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
- Department of Clinical Medicine, School of Medicine, Trinity College Dublin, Dublin, Ireland
| | - Ema Ozaki
- Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
- Department of Clinical Medicine, School of Medicine, Trinity College Dublin, Dublin, Ireland
| | - Chris Greene
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Anne Trappe
- School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Michael Carty
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland
- Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Judith A. Coppinger
- School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Andrew G. Bowie
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland
- Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Matthew Campbell
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Sarah L. Doyle
- Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin, Ireland
- Department of Clinical Medicine, School of Medicine, Trinity College Dublin, Dublin, Ireland
- *Correspondence: Sarah L. Doyle,
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20
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Lu Q, Botchway BOA, Zhang Y, Jin T, Liu X. SARM1 can be a potential therapeutic target for spinal cord injury. Cell Mol Life Sci 2022; 79:161. [PMID: 35224705 PMCID: PMC11072485 DOI: 10.1007/s00018-022-04195-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 01/26/2022] [Accepted: 02/05/2022] [Indexed: 01/03/2023]
Abstract
Injury to the spinal cord is devastating. Studies have implicated Wallerian degeneration as the main cause of axonal destruction in the wake of spinal cord injury. Therefore, the suppression of Wallerian degeneration could be beneficial for spinal cord injury treatment. Sterile alpha and armadillo motif-containing protein 1 (SARM1) is a key modulator of Wallerian degeneration, and its impediment can improve spinal cord injury to a significant degree. In this report, we analyze the various signaling domains of SARM1, the recent findings on Wallerian degeneration and its relation to axonal insults, as well as its connection to SARM1, the mitogen-activated protein kinase (MAPK) signaling, and the survival factor, nicotinamide mononucleotide adenylyltransferase 2 (NMNAT2). We then elaborate on the possible role of SARM1 in spinal cord injury and explicate how its obstruction could potentially alleviate the injury.
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Affiliation(s)
- Qicheng Lu
- Department of Histology and Embryology, Medical College, Shaoxing University, Shaoxing, China
| | - Benson O A Botchway
- Institute of Neuroscience, Zhejiang University School of Medicine, Hangzhou, China
| | - Yong Zhang
- Department of Histology and Embryology, Medical College, Shaoxing University, Shaoxing, China
| | - Tian Jin
- Department of Histology and Embryology, Medical College, Shaoxing University, Shaoxing, China
| | - Xuehong Liu
- Department of Histology and Embryology, Medical College, Shaoxing University, Shaoxing, China.
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21
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Crawford CL, Antoniou C, Komarek L, Schultz V, Donald CL, Montague P, Barnett SC, Linington C, Willison HJ, Kohl A, Coleman MP, Edgar JM. SARM1 Depletion Slows Axon Degeneration in a CNS Model of Neurotropic Viral Infection. Front Mol Neurosci 2022; 15:860410. [PMID: 35493328 PMCID: PMC9043327 DOI: 10.3389/fnmol.2022.860410] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Accepted: 02/18/2022] [Indexed: 01/30/2023] Open
Abstract
Zika virus (ZIKV) is a neurotropic flavivirus recently linked to congenital ZIKV syndrome in children and encephalitis and Guillain-Barré syndrome in adults. Neurotropic viruses often use axons to traffic to neuronal or glial cell somas where they either remain latent or replicate and proceed to infect new cells. Consequently, it has been suggested that axon degeneration could represent an evolutionarily conserved mechanism to limit viral spread. Whilst it is not known if ZIKV transits in axons, we previously reported that ZIKV infection of glial cells in a murine spinal cord-derived cell culture model of the CNS is associated with a profound loss of neuronal cell processes. This, despite that postmitotic neurons are relatively refractory to infection and death. Here, we tested the hypothesis that ZIKV-associated degeneration of neuronal processes is dependent on activation of Sterile alpha and armadillo motif-containing protein 1 (SARM1), an NADase that acts as a central executioner in a conserved axon degeneration pathway. To test this, we infected wild type and Sarm1 homozygous or heterozygous null cell cultures with ZIKV and examined NAD+ levels as well as the survival of neurons and their processes. Unexpectedly, ZIKV infection led to a rapid SARM1-independent reduction in NAD+. Nonetheless, the subsequent profound loss of neuronal cell processes was SARM1-dependent and was preceded by early changes in the appearance of β-tubulin III staining. Together, these data identify a role for SARM1 in the pathogenesis of ZIKV infection, which may reflect SARM1's conserved prodegenerative function, independent of its NADase activity.
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Affiliation(s)
- Colin L. Crawford
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | | | - Lina Komarek
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Verena Schultz
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Claire L. Donald
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Paul Montague
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Susan C. Barnett
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Christopher Linington
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Hugh J. Willison
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Alain Kohl
- MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Michael P. Coleman
- John van Geest Centre for Brain Repair, Cambridge, United Kingdom
- Michael P. Coleman
| | - Julia M. Edgar
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
- *Correspondence: Julia M. Edgar
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22
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Doran CG, Sugisawa R, Carty M, Roche F, Fergus C, Hokamp K, Kelly VP, Bowie AG. CRISPR/Cas9-mediated SARM1 knockout and epitope-tagged mice reveal that SARM1 does not regulate nuclear transcription, but is expressed in macrophages. J Biol Chem 2021; 297:101417. [PMID: 34793837 DOI: 10.1016/j.jbc.2021.101417] [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: 08/28/2021] [Revised: 11/03/2021] [Accepted: 11/08/2021] [Indexed: 10/19/2022] Open
Abstract
SARM1 is a toll/interleukin-1 receptor -domain containing protein, with roles proposed in both innate immunity and neuronal degeneration. Murine SARM1 has been reported to regulate the transcription of chemokines in both neurons and macrophages; however, the extent to which SARM1 contributes to transcription regulation remains to be fully understood. Here, we identify differential gene expression in bone-marrow-derived macrophages (BMDMs) from C57BL/6 congenic 129 ES cell-derived Sarm1-/- mice compared with wild type (WT). However, we found that passenger genes, which are derived from the 129 donor strain of mice that flank the Sarm1 locus, confound interpretation of the results, since many of the identified differentially regulated genes come from this region. To re-examine the transcriptional role of SARM1 in the absence of passenger genes, here we generated three Sarm1-/- mice using CRISPR/Cas9. Treatment of neurons from these mice with vincristine, a chemotherapeutic drug causing axonal degeneration, confirmed SARM1's function in that process; however, these mice also showed that lack of SARM1 has no impact on transcription of genes previously shown to be affected such as chemokines. To gain further insight into SARM1 function, we generated an epitope-tagged SARM1 mouse. In these mice, we observed high SARM1 protein expression in the brain and brainstem and lower but detectable levels in macrophages. Overall, the generation of these SARM1 knockout and epitope-tagged mice has clarified that SARM1 is expressed in mouse macrophages yet has no general role in macrophage transcriptional regulation and has provided important new models to further explore SARM1 function.
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Affiliation(s)
- Ciara G Doran
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Ryoichi Sugisawa
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Michael Carty
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Fiona Roche
- School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland
| | - Claire Fergus
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Karsten Hokamp
- School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland
| | - Vincent P Kelly
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland
| | - Andrew G Bowie
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland.
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23
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Bjanes E, Sillas RG, Matsuda R, Demarco B, Fettrelet T, DeLaney AA, Kornfeld OS, Lee BL, Rodríguez López EM, Grubaugh D, Wynosky-Dolfi MA, Philip NH, Krespan E, Tovar D, Joannas L, Beiting DP, Henao-Mejia J, Schaefer BC, Chen KW, Broz P, Brodsky IE. Genetic targeting of Card19 is linked to disrupted NINJ1 expression, impaired cell lysis, and increased susceptibility to Yersinia infection. PLoS Pathog 2021; 17:e1009967. [PMID: 34648590 PMCID: PMC8547626 DOI: 10.1371/journal.ppat.1009967] [Citation(s) in RCA: 24] [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: 05/16/2021] [Revised: 10/26/2021] [Accepted: 09/23/2021] [Indexed: 12/13/2022] Open
Abstract
Cell death plays a critical role in inflammatory responses. During pyroptosis, inflammatory caspases cleave Gasdermin D (GSDMD) to release an N-terminal fragment that generates plasma membrane pores that mediate cell lysis and IL-1 cytokine release. Terminal cell lysis and IL-1β release following caspase activation can be uncoupled in certain cell types or in response to particular stimuli, a state termed hyperactivation. However, the factors and mechanisms that regulate terminal cell lysis downstream of GSDMD cleavage remain poorly understood. In the course of studies to define regulation of pyroptosis during Yersinia infection, we identified a line of Card19-deficient mice (Card19lxcn) whose macrophages were protected from cell lysis and showed reduced apoptosis and pyroptosis, yet had wild-type levels of caspase activation, IL-1 secretion, and GSDMD cleavage. Unexpectedly, CARD19, a mitochondrial CARD-containing protein, was not directly responsible for this, as an independently-generated CRISPR/Cas9 Card19 knockout mouse line (Card19Null) showed no defect in macrophage cell lysis. Notably, Card19 is located on chromosome 13, immediately adjacent to Ninj1, which was recently found to regulate cell lysis downstream of GSDMD activation. RNA-seq and western blotting revealed that Card19lxcn BMDMs have significantly reduced NINJ1 expression, and reconstitution of Ninj1 in Card19lxcn immortalized BMDMs restored their ability to undergo cell lysis in response to caspase-dependent cell death stimuli. Card19lxcn mice exhibited increased susceptibility to Yersinia infection, whereas independently-generated Card19Null mice did not, demonstrating that cell lysis itself plays a key role in protection against bacterial infection, and that the increased infection susceptibility of Card19lxcn mice is attributable to loss of NINJ1. Our findings identify genetic targeting of Card19 being responsible for off-target effects on the adjacent gene Ninj1, disrupting the ability of macrophages to undergo plasma membrane rupture downstream of gasdermin cleavage and impacting host survival and bacterial control during Yersinia infection.
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Affiliation(s)
- Elisabet Bjanes
- Cell and Molecular Biology Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, United States of America
| | - Reyna Garcia Sillas
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, United States of America
| | - Rina Matsuda
- Cell and Molecular Biology Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, United States of America
| | - Benjamin Demarco
- Department of Biochemistry, University of Lausanne, Epalinges, Vaud, Switzerland
| | - Timothée Fettrelet
- Department of Biochemistry, University of Lausanne, Epalinges, Vaud, Switzerland
| | - Alexandra A. DeLaney
- Cell and Molecular Biology Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, United States of America
| | - Opher S. Kornfeld
- Department of Physiological Chemistry, Genentech Inc., South San Francisco, California, United States of America
| | - Bettina L. Lee
- Department of Physiological Chemistry, Genentech Inc., South San Francisco, California, United States of America
| | - Eric M. Rodríguez López
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, United States of America
- Immunology Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Daniel Grubaugh
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, United States of America
| | - Meghan A. Wynosky-Dolfi
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, United States of America
| | - Naomi H. Philip
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, United States of America
- Immunology Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Elise Krespan
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, United States of America
- Center for Host Microbial Interactions, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, United States of America
| | - Dorothy Tovar
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, United States of America
| | - Leonel Joannas
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, United States of America
- CRISPR/Cas9 Mouse Targeting Core, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, United States of America
| | - Daniel P. Beiting
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, United States of America
- Center for Host Microbial Interactions, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, United States of America
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Jorge Henao-Mejia
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- Division of Protective Immunity, Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Brian C. Schaefer
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, Maryland, United States of America
| | - Kaiwen W. Chen
- Department of Biochemistry, University of Lausanne, Epalinges, Vaud, Switzerland
| | - Petr Broz
- Department of Biochemistry, University of Lausanne, Epalinges, Vaud, Switzerland
| | - Igor E. Brodsky
- Cell and Molecular Biology Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, United States of America
- Immunology Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
- Institute for Immunology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
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24
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Hopkins EL, Gu W, Kobe B, Coleman MP. A Novel NAD Signaling Mechanism in Axon Degeneration and its Relationship to Innate Immunity. Front Mol Biosci 2021; 8:703532. [PMID: 34307460 PMCID: PMC8295901 DOI: 10.3389/fmolb.2021.703532] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 06/28/2021] [Indexed: 12/21/2022] Open
Abstract
Axon degeneration represents a pathological feature of many neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease where axons die before the neuronal soma, and axonopathies, such as Charcot-Marie-Tooth disease and hereditary spastic paraplegia. Over the last two decades, it has slowly emerged that a central signaling pathway forms the basis of this process in many circumstances. This is an axonal NAD-related signaling mechanism mainly regulated by the two key proteins with opposing roles: the NAD-synthesizing enzyme NMNAT2, and SARM1, a protein with NADase and related activities. The crosstalk between the axon survival factor NMNAT2 and pro-degenerative factor SARM1 has been extensively characterized and plays an essential role in maintaining the axon integrity. This pathway can be activated in necroptosis and in genetic, toxic or metabolic disorders, physical injury and neuroinflammation, all leading to axon pathology. SARM1 is also known to be involved in regulating innate immunity, potentially linking axon degeneration to the response to pathogens and intercellular signaling. Understanding this NAD-related signaling mechanism enhances our understanding of the process of axon degeneration and enables a path to the development of drugs for a wide range of neurodegenerative diseases.
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Affiliation(s)
- Eleanor L. Hopkins
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - Weixi Gu
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, QLD, Australia
| | - Michael P. Coleman
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
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25
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Neuroprotection in Glaucoma: NAD +/NADH Redox State as a Potential Biomarker and Therapeutic Target. Cells 2021; 10:cells10061402. [PMID: 34198948 PMCID: PMC8226607 DOI: 10.3390/cells10061402] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/24/2021] [Accepted: 05/27/2021] [Indexed: 02/07/2023] Open
Abstract
Glaucoma is the leading cause of irreversible blindness worldwide. Its prevalence and incidence increase exponentially with age and the level of intraocular pressure (IOP). IOP reduction is currently the only therapeutic modality shown to slow glaucoma progression. However, patients still lose vision despite best treatment, suggesting that other factors confer susceptibility. Several studies indicate that mitochondrial function may underlie both susceptibility and resistance to developing glaucoma. Mitochondria meet high energy demand, in the form of ATP, that is required for the maintenance of optimum retinal ganglion cell (RGC) function. Reduced nicotinamide adenine dinucleotide (NAD+) levels have been closely correlated to mitochondrial dysfunction and have been implicated in several neurodegenerative diseases including glaucoma. NAD+ is at the centre of various metabolic reactions culminating in ATP production—essential for RGC function. In this review we present various pathways that influence the NAD+(H) redox state, affecting mitochondrial function and making RGCs susceptible to degeneration. Such disruptions of the NAD+(H) redox state are generalised and not solely induced in RGCs because of high IOP. This places the NAD+(H) redox state as a potential systemic biomarker for glaucoma susceptibility and progression; a hypothesis which may be tested in clinical trials and then translated to clinical practice.
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26
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Bradshaw DV, Knutsen AK, Korotcov A, Sullivan GM, Radomski KL, Dardzinski BJ, Zi X, McDaniel DP, Armstrong RC. Genetic inactivation of SARM1 axon degeneration pathway improves outcome trajectory after experimental traumatic brain injury based on pathological, radiological, and functional measures. Acta Neuropathol Commun 2021; 9:89. [PMID: 34001261 PMCID: PMC8130449 DOI: 10.1186/s40478-021-01193-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 05/06/2021] [Indexed: 02/07/2023] Open
Abstract
Traumatic brain injury (TBI) causes chronic symptoms and increased risk of neurodegeneration. Axons in white matter tracts, such as the corpus callosum (CC), are critical components of neural circuits and particularly vulnerable to TBI. Treatments are needed to protect axons from traumatic injury and mitigate post-traumatic neurodegeneration. SARM1 protein is a central driver of axon degeneration through a conserved molecular pathway. Sarm1−/− mice with knockout (KO) of the Sarm1 gene enable genetic proof-of-concept testing of the SARM1 pathway as a therapeutic target. We evaluated Sarm1 deletion effects after TBI using a concussive model that causes traumatic axonal injury and progresses to CC atrophy at 10 weeks, indicating post-traumatic neurodegeneration. Sarm1 wild-type (WT) mice developed significant CC atrophy that was reduced in Sarm1 KO mice. Ultrastructural classification of pathology of individual axons, using electron microscopy, demonstrated that Sarm1 KO preserved more intact axons and reduced damaged or demyelinated axons. Longitudinal MRI studies in live mice identified significantly reduced CC volume after TBI in Sarm1 WT mice that was attenuated in Sarm1 KO mice. MR diffusion tensor imaging detected reduced fractional anisotropy in both genotypes while axial diffusivity remained higher in Sarm1 KO mice. Immunohistochemistry revealed significant attenuation of CC atrophy, myelin loss, and neuroinflammation in Sarm1 KO mice after TBI. Functionally, Sarm1 KO mice exhibited beneficial effects in motor learning and sleep behavior. Based on these findings, Sarm1 inactivation can protect axons and white matter tracts to improve translational outcomes associated with CC atrophy and post-traumatic neurodegeneration.
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27
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Ocular phenotypes in a mouse model of impaired glucocerebrosidase activity. Sci Rep 2021; 11:6079. [PMID: 33727605 PMCID: PMC7971029 DOI: 10.1038/s41598-021-85528-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 03/02/2021] [Indexed: 01/08/2023] Open
Abstract
Mutations in the GBA1 gene encoding glucocerebrosidase (GCase) are linked to Gaucher (GD) and Parkinson's Disease (PD). Since some GD and PD patients develop ocular phenotypes, we determined whether ocular phenotypes might result from impaired GCase activity and the corresponding accumulation of glucosylceramide (GluCer) and glucosylsphingosine (GluSph) in the Gba1D409V/D409V knock-in (Gba KI/KI; "KI") mouse. Gba KI mice developed age-dependent pupil dilation deficits to an anti-muscarinic agent; histologically, the iris covered the anterior part of the lens with adhesions between the iris and the anterior surface of the lens (posterior synechia). This may prevent pupil dilation in general, beyond an un-responsiveness of the iris to anti-muscarinics. Gba KI mice displayed atrophy and pigment dispersion of the iris, and occlusion of the iridocorneal angle by pigment-laden cells, reminiscent of secondary open angle glaucoma. Gba KI mice showed progressive thinning of the retina consistent with retinal degeneration. GluSph levels were increased in the anterior and posterior segments of the eye, suggesting that accumulation of lipids in the eye may contribute to degeneration in this compartment. We conclude that the Gba KI model provides robust and reproducible eye phenotypes which may be used to test for efficacy and establish biomarkers for GBA1-related therapies.
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28
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Covarrubias AJ, Perrone R, Grozio A, Verdin E. NAD + metabolism and its roles in cellular processes during ageing. Nat Rev Mol Cell Biol 2021; 22:119-141. [PMID: 33353981 PMCID: PMC7963035 DOI: 10.1038/s41580-020-00313-x] [Citation(s) in RCA: 797] [Impact Index Per Article: 199.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/02/2020] [Indexed: 12/13/2022]
Abstract
Nicotinamide adenine dinucleotide (NAD+) is a coenzyme for redox reactions, making it central to energy metabolism. NAD+ is also an essential cofactor for non-redox NAD+-dependent enzymes, including sirtuins, CD38 and poly(ADP-ribose) polymerases. NAD+ can directly and indirectly influence many key cellular functions, including metabolic pathways, DNA repair, chromatin remodelling, cellular senescence and immune cell function. These cellular processes and functions are critical for maintaining tissue and metabolic homeostasis and for healthy ageing. Remarkably, ageing is accompanied by a gradual decline in tissue and cellular NAD+ levels in multiple model organisms, including rodents and humans. This decline in NAD+ levels is linked causally to numerous ageing-associated diseases, including cognitive decline, cancer, metabolic disease, sarcopenia and frailty. Many of these ageing-associated diseases can be slowed down and even reversed by restoring NAD+ levels. Therefore, targeting NAD+ metabolism has emerged as a potential therapeutic approach to ameliorate ageing-related disease, and extend the human healthspan and lifespan. However, much remains to be learnt about how NAD+ influences human health and ageing biology. This includes a deeper understanding of the molecular mechanisms that regulate NAD+ levels, how to effectively restore NAD+ levels during ageing, whether doing so is safe and whether NAD+ repletion will have beneficial effects in ageing humans.
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Affiliation(s)
- Anthony J Covarrubias
- Buck Institute for Research on Aging, Novato, CA, USA
- UCSF Department of Medicine, San Francisco, CA, USA
| | | | | | - Eric Verdin
- Buck Institute for Research on Aging, Novato, CA, USA.
- UCSF Department of Medicine, San Francisco, CA, USA.
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Gould SA, White M, Wilbrey AL, Pór E, Coleman MP, Adalbert R. Protection against oxaliplatin-induced mechanical and thermal hypersensitivity in Sarm1 -/- mice. Exp Neurol 2021; 338:113607. [PMID: 33460644 DOI: 10.1016/j.expneurol.2021.113607] [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: 10/14/2020] [Revised: 01/07/2021] [Accepted: 01/09/2021] [Indexed: 12/22/2022]
Abstract
Chemotherapy-induced peripheral neuropathy (CIPN) is a common dose-limiting side effect of cancer treatment, often associated with degeneration of sensory axons or their terminal regions. Presence of the slow Wallerian degeneration protein (WLDS), or genetic deletion of sterile alpha and TIR motif containing protein 1 (SARM1), which strongly protect axons from degeneration after injury or axonal transport block, alleviate pain in several CIPN models. However, oxaliplatin can cause an acute pain response, suggesting a different mechanism of pain generation. Here, we tested whether the presence of WLDS or absence of SARM1 protects against acute oxaliplatin-induced pain in mice after a single oxaliplatin injection. In BL/6 and WldS mice, oxaliplatin induced significant mechanical and cold hypersensitivities which were absent in Sarm1-/- mice. Despite the presence of hypersensitivity there was no significant loss of intraepidermal nerve fibers (IENFs) in the footpads of any mice after oxaliplatin treatment, suggesting that early stages of pain hypersensitivity could be independent of axon degeneration. To identify other changes that could underlie the pain response, RNA sequencing was carried out in DRGs from treated and control mice of each genotype. Sarm1-/- mice had fewer gene expression changes than either BL/6 or WldS mice. This is consistent with the pain measurements in demonstrating that Sarm1-/- DRGs remain relatively unchanged after oxaliplatin treatment, unlike those in BL/6 and WldS mice. Changes in levels of four transcripts - Alas2, Hba-a1, Hba-a2, and Tfrc - correlated with oxaliplatin-induced pain, or absence thereof, across the three genotypes. Our findings suggest that targeting SARM1 could be a viable therapeutic approach to prevent oxaliplatin-induced acute neuropathic pain.
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Affiliation(s)
- Stacey Anne Gould
- John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, UK; The Babraham Institute, Cambridge, UK
| | - Matthew White
- The Babraham Institute, Cambridge, UK; Department of Basic and Clinical Neuroscience, The Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London, London SE5 9RT, UK
| | - Anna L Wilbrey
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Erzsébet Pór
- Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Szeged, Szeged H-6724, Hungary
| | - Michael Philip Coleman
- John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, UK; The Babraham Institute, Cambridge, UK
| | - Robert Adalbert
- John van Geest Centre for Brain Repair, University of Cambridge, Cambridge, UK; The Babraham Institute, Cambridge, UK; Department of Anatomy, Histology and Embryology, Faculty of Medicine, University of Szeged, Szeged H-6724, Hungary.
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Sporny M, Guez-Haddad J, Khazma T, Yaron A, Dessau M, Shkolnisky Y, Mim C, Isupov MN, Zalk R, Hons M, Opatowsky Y. Structural basis for SARM1 inhibition and activation under energetic stress. eLife 2020; 9:e62021. [PMID: 33185189 PMCID: PMC7688312 DOI: 10.7554/elife.62021] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 11/12/2020] [Indexed: 12/24/2022] Open
Abstract
SARM1, an executor of axonal degeneration, displays NADase activity that depletes the key cellular metabolite, NAD+, in response to nerve injury. The basis of SARM1 inhibition and its activation under stress conditions are still unknown. Here, we present cryo-EM maps of SARM1 at 2.9 and 2.7 Å resolutions. These indicate that SARM1 homo-octamer avoids premature activation by assuming a packed conformation, with ordered inner and peripheral rings, that prevents dimerization and activation of the catalytic domains. This inactive conformation is stabilized by binding of SARM1's own substrate NAD+ in an allosteric location, away from the catalytic sites. This model was validated by mutagenesis of the allosteric site, which led to constitutively active SARM1. We propose that the reduction of cellular NAD+ concentration contributes to the disassembly of SARM1's peripheral ring, which allows formation of active NADase domain dimers, thereby further depleting NAD+ to cause an energetic catastrophe and cell death.
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Affiliation(s)
- Michael Sporny
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan UniversityRamat-GanIsrael
| | - Julia Guez-Haddad
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan UniversityRamat-GanIsrael
| | - Tami Khazma
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan UniversityRamat-GanIsrael
| | - Avraham Yaron
- Department of Biomolecular Sciences, Weizmann Institute of ScienceRehovotIsrael
| | - Moshe Dessau
- Azrieli Faculty of Medicine, Bar Ilan UniversitySafedIsrael
| | - Yoel Shkolnisky
- Department of Applied Mathematics, School of Mathematical Sciences, Tel-Aviv UniversityTel-AvivIsrael
| | - Carsten Mim
- Royal Technical Institute (KTH), Dept. For Biomedical Engineering and Health SystemsStockholmSweden
| | | | - Ran Zalk
- National Institute for Biotechnology in the Negev, Ben-Gurion University of the NegevBeer-ShevaIsrael
| | - Michael Hons
- European Molecular Biology LaboratoryGrenobleFrance
| | - Yarden Opatowsky
- The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan UniversityRamat-GanIsrael
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Viar K, Njoku D, Secor McVoy J, Oh U. Sarm1 knockout protects against early but not late axonal degeneration in experimental allergic encephalomyelitis. PLoS One 2020; 15:e0235110. [PMID: 32584865 PMCID: PMC7316289 DOI: 10.1371/journal.pone.0235110] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 06/08/2020] [Indexed: 01/20/2023] Open
Abstract
Programmed axonal degeneration, also known as Wallerian degeneration, occurs in immune-mediated central nervous system (CNS) inflammatory disorders such as multiple sclerosis and the animal model experimental allergic encephalomyelitis (EAE). Sterile alpha and TIR domain containing protein 1 (SARM1) functions to promote programmed axonal degeneration. To test the hypothesis that loss of SARM1 will reduce axonal degeneration in immune-mediated CNS inflammatory disorders, the course and pathology of EAE was compared in Sarm1 knockout mice and wild type littermates. The clinical course of EAE was similar in Sarm1 knockout and wild type. Analysis of EAE in mice expressing neuronal yellow fluorescent protein (YFP) showed significantly less axonal degeneration in Sarm1 knockout mice compared to wild type littermates at 14 days post-induction of EAE. At 21 days post-induction, however, difference in axonal degeneration was not significant. At 42 days post-induction, Sarm1 knockout mice were indistinguishable from wild type with respect to markers of axonal injury, and were similar with respect to axonal density in the lumbar cords. There was no significant change in peripheral immune activation or CNS inflammatory cell infiltration associated with EAE in Sarm1 knockout mice. In conclusion, Sarm1 deletion delayed axonal degeneration early in the course of CNS inflammation, but did not confer long-term protection from axonal degeneration in an animal model of immune-mediated CNS inflammation.
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Affiliation(s)
- Kenneth Viar
- Department of Neurology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States of America
| | - Daniel Njoku
- Department of Neurology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States of America
| | - Julie Secor McVoy
- Department of Neurology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States of America
| | - Unsong Oh
- Department of Neurology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, United States of America
- * E-mail:
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