1
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Zhang Y, Yao Y, Yang J, Zhou B, Zhu Y. Inhibiting the SARM1-NAD + axis reduces oxidative stress-induced damage to retinal and nerve cells. Int Immunopharmacol 2024; 134:112193. [PMID: 38723372 DOI: 10.1016/j.intimp.2024.112193] [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: 02/10/2024] [Revised: 04/17/2024] [Accepted: 04/29/2024] [Indexed: 06/03/2024]
Abstract
Retinal neurodegenerative diseases are a category of refractory blinding eye conditions closely associated with oxidative stress induced by mitochondrial dysfunction in retinal cells. SARM1, a core driver molecule leading to axonal degeneration, possesses NAD+ enzyme (NADase) activity. However, the role of the SARM1-NAD+ axis in oxidative stress-induced retinal cell death remains unclear. Here, we employed the SARM1 NADase inhibitor DSRM-3716 and established a glucose oxidase (GOx)-induced oxidative stress cell model. We found that compared to the GOx group, the DSRM-3716 pre-treated group reduced the hydrolysis of NAD+, inhibited the elevation of oxidative stress markers induced by GOx, decreased mitochondrial dysfunction, lowered the phosphorylation level of JNK, and attenuated the occurrence of pyroptosis in retinal and nerve cells, thereby providing protection for neurite growth. Further utilization of the JNK activator Anisomycin activated JNK, revealed that the JNK/c-Jun pathway down-regulated NMNAT2 expression. Consequently, it reduced cellular NAD+ synthesis, exacerbated mitochondrial dysfunction and cell pyroptosis, and reversed the protective effect of DSRM-3716 on cells. In summary, the inhibition of SARM1 NADase activity substantially mitigates oxidative damage to retinal cells and mitochondrial damage. Additionally, JNK simultaneously serves as both an upstream and downstream regulator in the SARM1-NAD+ axis, regulating retinal cell pyroptosis and neurite injury. Thus, this study provides new insights into the pathological processes of retinal cell oxidative stress and identifies potential therapeutic targets for retinal neurodegenerative diseases.
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Affiliation(s)
- Yannan Zhang
- Department of Ophthalmology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian Province, China; Department of Ophthalmology, National Regional Medical Center, Binghai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, China; Fujian Institute of Ophthalmology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China; Fujian Provincial Clinical Medical Research Center of Eye Diseases and Optometry, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Yihua Yao
- Department of Ophthalmology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian Province, China; Department of Ophthalmology, National Regional Medical Center, Binghai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, China; Fujian Institute of Ophthalmology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China; Fujian Provincial Clinical Medical Research Center of Eye Diseases and Optometry, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Juhua Yang
- The School of Pharmacy, Fujian Medical University, Fuzhou, Fujian Province, China
| | - Biting Zhou
- Department of Ophthalmology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian Province, China; Department of Ophthalmology, National Regional Medical Center, Binghai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, China; Fujian Institute of Ophthalmology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China; Fujian Provincial Clinical Medical Research Center of Eye Diseases and Optometry, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China.
| | - Yihua Zhu
- Department of Ophthalmology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian Province, China; Department of Ophthalmology, National Regional Medical Center, Binghai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou, China; Fujian Institute of Ophthalmology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China; Fujian Provincial Clinical Medical Research Center of Eye Diseases and Optometry, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China.
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2
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Miao X, Wu Q, Du S, Xiang L, Zhou S, Zhu J, Chen Z, Wang H, Pan X, Fan Y, Zhang L, Qian J, Xing Y, Xie Y, Hu L, Xu H, Wang W, Wang Y, Huang Z. SARM1 Promotes Neurodegeneration and Memory Impairment in Mouse Models of Alzheimer's Disease. Aging Dis 2024; 15:390-407. [PMID: 37307837 PMCID: PMC10796105 DOI: 10.14336/ad.2023.0516-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 05/16/2023] [Indexed: 06/14/2023] Open
Abstract
Neuroinflammation plays a crucial role in the pathogenesis and progression of Alzheimer's disease (AD). The Sterile Alpha and Toll Interleukin Receptor Motif-containing protein 1 (SARM1) has been shown to promote axonal degeneration and is involved in neuroinflammation. However, the role of SARM1 in AD remains unclear. In this study, we found that SARM1 was reduced in hippocampal neurons of AD model mice. Interestingly, conditional knockout (CKO) of SARM1 in the central nervous system (CNS, SARM1Nestin-CKO mice) delayed the cognitive decline in APP/PS1 AD model mice. Furthermore, SARM1 deletion reduced the Aβ deposition and inflammatory infiltration in the hippocampus and inhibited neurodegeneration in APP/PS1 AD model mice. Further investigation into the underlying mechanisms revealed that the signaling of tumor necrosis factor-α (TNF-α) was downregulated in the hippocampus tissues of APP/PS1;SARM1Nestin-CKO mice, thereby alleviating the cognitive decline, Aβ deposition and inflammatory infiltration. These findings identify unrecognized functions of SARM1 in promoting AD and reveal the SARM1-TNF-α pathway in AD model mice.
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Affiliation(s)
- Xuemeng Miao
- College of Pharmacy, Hangzhou Normal University, Hangzhou, Zhejiang 311121, China.
- School of Mental Health, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China.
| | - Qian Wu
- School of Mental Health, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China.
| | - Siyu Du
- School of Mental Health, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China.
| | - Ludan Xiang
- School of Mental Health, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China.
| | - Siyao Zhou
- School of Mental Health, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China.
| | - Junzhe Zhu
- School of the First Clinical Medical Sciences, School of Information and Engineering, Wenzhou Medical University, Wenzhou, Zhejiang 325205, China.
| | - Zirun Chen
- School of Mental Health, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China.
| | - Hui Wang
- School of the First Clinical Medical Sciences, School of Information and Engineering, Wenzhou Medical University, Wenzhou, Zhejiang 325205, China.
| | - Xuyi Pan
- School of the First Clinical Medical Sciences, School of Information and Engineering, Wenzhou Medical University, Wenzhou, Zhejiang 325205, China.
| | - Yiren Fan
- School of the First Clinical Medical Sciences, School of Information and Engineering, Wenzhou Medical University, Wenzhou, Zhejiang 325205, China.
| | - Lihan Zhang
- School of the First Clinical Medical Sciences, School of Information and Engineering, Wenzhou Medical University, Wenzhou, Zhejiang 325205, China.
| | - Jingkang Qian
- School of the First Clinical Medical Sciences, School of Information and Engineering, Wenzhou Medical University, Wenzhou, Zhejiang 325205, China.
| | - Yuxuan Xing
- School of the First Clinical Medical Sciences, School of Information and Engineering, Wenzhou Medical University, Wenzhou, Zhejiang 325205, China.
| | - Yiyang Xie
- School of the First Clinical Medical Sciences, School of Information and Engineering, Wenzhou Medical University, Wenzhou, Zhejiang 325205, China.
| | - Lixin Hu
- School of Mental Health, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China.
| | - Haiyun Xu
- School of Mental Health, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China.
| | - Wei Wang
- School of Mental Health, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China.
| | - Ying Wang
- Clinical Research Center, Affiliated Hangzhou First People’s Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310003, China.
| | - Zhihui Huang
- College of Pharmacy, Hangzhou Normal University, Hangzhou, Zhejiang 311121, China.
- School of Mental Health, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China.
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3
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Chiarugi A. Glaucoma: neuroprotection with NAD-based therapeutic interventions. Trends Pharmacol Sci 2023; 44:869-879. [PMID: 37880000 DOI: 10.1016/j.tips.2023.09.010] [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: 09/06/2023] [Revised: 09/22/2023] [Accepted: 09/26/2023] [Indexed: 10/27/2023]
Abstract
Clinical evidence shows that intraocular hypertension is not the primary pathogenetic event of glaucoma, whereas early neurodegeneration of retinal ganglion cells (RGCs) represents a key therapeutic target. Unfortunately, failure of clinical trials with neuroprotective agents, in particular those testing the anti-excitotoxic drug memantine, generated widespread skepticism regarding the possibility of counteracting neurodegeneration during glaucoma. New avenues for neuroprotective approaches to counteract glaucoma evolution have been opened by the identification of a programmed axonal degeneration (PAD) program triggered by increased nicotinamide mononucleotide (NMN)/NAD concentration ratio. Positive results of proof-of-concept clinical studies based on sustaining axonal NAD homeostasis facilitated the design of Phase 2/3 trials. Here, I share my opinion on how neurodegeneration in glaucoma should be put into context, together with an appraisal of the pharmacological rationale of NAD-supporting therapies for use during glaucoma progression.
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Affiliation(s)
- Alberto Chiarugi
- Section of Clinical Pharmacology and Oncology, Department of Health Sciences, University of Florence, Florence, Italy; Headache Center and Clinical Pharmacology Unit, Careggi University Hospital, Florence, Italy.
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4
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Liu S, Zhang W. NAD + metabolism and eye diseases: current status and future directions. Mol Biol Rep 2023; 50:8653-8663. [PMID: 37540459 DOI: 10.1007/s11033-023-08692-y] [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: 05/16/2023] [Accepted: 07/18/2023] [Indexed: 08/05/2023]
Abstract
Currently, there are no truly effective treatments for a variety of eye diseases, such as glaucoma, age-related macular degeneration (AMD), and inherited retinal degenerations (IRDs). These conditions have a significant impact on patients' quality of life and can be a burden on society. However, these diseases share a common pathological process of NAD+ metabolism disorders. They are either associated with genetically induced primary NAD+ synthase deficiency, decreased NAD+ levels due to aging, or enhanced NAD+ consuming enzyme activity during disease pathology. In this discussion, we explore the role of NAD+ metabolic disorders in the development of associated ocular diseases and the potential advantages and disadvantages of various methods to increase NAD+ levels. It is essential to carefully evaluate the possible adverse effects of these methods and conduct a more comprehensive and objective assessment of their function before considering their use.
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Affiliation(s)
- Siyuan Liu
- Department of Ophthalmology, Second Clinical Medical College, Lanzhou University, 730030, Lanzhou, VA, China
| | - Wenfang Zhang
- Department of Ophthalmology, The Second Hospital of Lanzhou University, 730030, Lanzhou, VA, China.
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5
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Barroso M, Monaghan MG, Niesner R, Dmitriev RI. Probing organoid metabolism using fluorescence lifetime imaging microscopy (FLIM): The next frontier of drug discovery and disease understanding. Adv Drug Deliv Rev 2023; 201:115081. [PMID: 37647987 PMCID: PMC10543546 DOI: 10.1016/j.addr.2023.115081] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 04/20/2023] [Accepted: 08/24/2023] [Indexed: 09/01/2023]
Abstract
Organoid models have been used to address important questions in developmental and cancer biology, tissue repair, advanced modelling of disease and therapies, among other bioengineering applications. Such 3D microenvironmental models can investigate the regulation of cell metabolism, and provide key insights into the mechanisms at the basis of cell growth, differentiation, communication, interactions with the environment and cell death. Their accessibility and complexity, based on 3D spatial and temporal heterogeneity, make organoids suitable for the application of novel, dynamic imaging microscopy methods, such as fluorescence lifetime imaging microscopy (FLIM) and related decay time-assessing readouts. Several biomarkers and assays have been proposed to study cell metabolism by FLIM in various organoid models. Herein, we present an expert-opinion discussion on the principles of FLIM and PLIM, instrumentation and data collection and analysis protocols, and general and emerging biosensor-based approaches, to highlight the pioneering work being performed in this field.
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Affiliation(s)
- Margarida Barroso
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY 12208, USA
| | - Michael G Monaghan
- Department of Mechanical, Manufacturing and Biomedical Engineering, Trinity College Dublin, Dublin 02, Ireland
| | - Raluca Niesner
- Dynamic and Functional In Vivo Imaging, Freie Universität Berlin and Biophysical Analytics, German Rheumatism Research Center, Berlin, Germany
| | - Ruslan I Dmitriev
- Tissue Engineering and Biomaterials Group, Department of Human Structure and Repair, Faculty of Medicine and Health Sciences, Ghent University, C. Heymanslaan 10, 9000 Ghent, Belgium; Ghent Light Microscopy Core, Ghent University, 9000 Ghent, Belgium.
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6
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Yang S, Park JH, Lu HC. Axonal energy metabolism, and the effects in aging and neurodegenerative diseases. Mol Neurodegener 2023; 18:49. [PMID: 37475056 PMCID: PMC10357692 DOI: 10.1186/s13024-023-00634-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 06/08/2023] [Indexed: 07/22/2023] Open
Abstract
Human studies consistently identify bioenergetic maladaptations in brains upon aging and neurodegenerative disorders of aging (NDAs), such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and Amyotrophic lateral sclerosis. Glucose is the major brain fuel and glucose hypometabolism has been observed in brain regions vulnerable to aging and NDAs. Many neurodegenerative susceptible regions are in the topological central hub of the brain connectome, linked by densely interconnected long-range axons. Axons, key components of the connectome, have high metabolic needs to support neurotransmission and other essential activities. Long-range axons are particularly vulnerable to injury, neurotoxin exposure, protein stress, lysosomal dysfunction, etc. Axonopathy is often an early sign of neurodegeneration. Recent studies ascribe axonal maintenance failures to local bioenergetic dysregulation. With this review, we aim to stimulate research in exploring metabolically oriented neuroprotection strategies to enhance or normalize bioenergetics in NDA models. Here we start by summarizing evidence from human patients and animal models to reveal the correlation between glucose hypometabolism and connectomic disintegration upon aging/NDAs. To encourage mechanistic investigations on how axonal bioenergetic dysregulation occurs during aging/NDAs, we first review the current literature on axonal bioenergetics in distinct axonal subdomains: axon initial segments, myelinated axonal segments, and axonal arbors harboring pre-synaptic boutons. In each subdomain, we focus on the organization, activity-dependent regulation of the bioenergetic system, and external glial support. Second, we review the mechanisms regulating axonal nicotinamide adenine dinucleotide (NAD+) homeostasis, an essential molecule for energy metabolism processes, including NAD+ biosynthetic, recycling, and consuming pathways. Third, we highlight the innate metabolic vulnerability of the brain connectome and discuss its perturbation during aging and NDAs. As axonal bioenergetic deficits are developing into NDAs, especially in asymptomatic phase, they are likely exaggerated further by impaired NAD+ homeostasis, the high energetic cost of neural network hyperactivity, and glial pathology. Future research in interrogating the causal relationship between metabolic vulnerability, axonopathy, amyloid/tau pathology, and cognitive decline will provide fundamental knowledge for developing therapeutic interventions.
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Affiliation(s)
- Sen Yang
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA
| | - Jung Hyun Park
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA
| | - Hui-Chen Lu
- The Linda and Jack Gill Center for Biomolecular Sciences, Indiana University, Bloomington, IN, 47405, USA.
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, 47405, USA.
- Program in Neuroscience, Indiana University, Bloomington, IN, 47405, USA.
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7
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Millar J, Campbell S, Duckett C, Doyle S, Cole LM. MALDI and Trace Metal Analysis in Age-Related Macular Degeneration. Methods Mol Biol 2023; 2688:1-13. [PMID: 37410279 DOI: 10.1007/978-1-0716-3319-9_1] [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: 07/07/2023]
Abstract
Age-related macular degeneration (AMD) remains one of the most prevalent causes of blindness throughout the world. Key to prevention of AMD is furthering the understanding of its pathology. In recent years, both the proteins within the innate immune system and essential and non-essential metals have been implicated in the pathology of AMD. Herein, a multidisciplinary and multimodal methodology has been taken to further our understanding of the role of the innate immune proteins and the essential metals within mouse ocular tissue.
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Affiliation(s)
- Joshua Millar
- Centre for Mass Spectrometry Imaging, Biomolecular Sciences Research Centre, Sheffield Hallam University, Sheffield, UK
| | - Susan Campbell
- Centre for Mass Spectrometry Imaging, Biomolecular Sciences Research Centre, Sheffield Hallam University, Sheffield, UK
| | - Catherine Duckett
- Centre for Mass Spectrometry Imaging, Biomolecular Sciences Research Centre, Sheffield Hallam University, Sheffield, UK
| | - Sarah Doyle
- Immunobiology Research Group, Department of Clinical Medicine, Trinity College Institute of Neuro-science (TCIN), School of Medicine, Trinity College Dublin (TCD), Dublin, Ireland
| | - Laura M Cole
- Centre for Mass Spectrometry Imaging, Biomolecular Sciences Research Centre, Sheffield Hallam University, Sheffield, UK.
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8
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Brown EE, Scandura MJ, Pierce E. Role of Nuclear NAD + in Retinal Homeostasis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1415:235-239. [PMID: 37440039 DOI: 10.1007/978-3-031-27681-1_34] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
The retina is one of the most metabolically active tissues and maintenance of metabolic homeostasis is critical for retinal function. Nicotinamide adenine dinucleotide (NAD+) is a cofactor that is required for key processes, including the electron transport chain, glycolysis, fatty acid oxidation, and redox reactions. NAD+ also acts as a co-substrate for enzymes involved in maintaining genomic DNA integrity and cellular homeostasis, including poly-ADP ribose polymerases (PARPs) and Sirtuins. This review highlights the importance of NAD+ in the retina, including the role of enzymes involved in NAD+ production in the retina and how NAD+-consuming enzymes may play a role in disease pathology. We also suggest a cell death pathway that may be common in multiple models of photoreceptor degeneration and highlight the role that NAD+ likely plays in this process. Finally, we explore future experimental approaches to enhance our understanding of the role of NAD+ in the retina.
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Affiliation(s)
- Emily E Brown
- Ocular Genomics Institute, Massachusetts Eye and Ear, Boston, MA, USA
- Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Michael J Scandura
- Ocular Genomics Institute, Massachusetts Eye and Ear, Boston, MA, USA
- Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Eric Pierce
- Ocular Genomics Institute, Massachusetts Eye and Ear, Boston, MA, USA.
- Department of Ophthalmology, Harvard Medical School, Boston, MA, USA.
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9
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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: 1.0] [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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10
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Multiomic Mass Spectrometry Imaging to Advance Future Pathological Understanding of Ocular Disease. Metabolites 2022; 12:metabo12121239. [PMID: 36557277 PMCID: PMC9786289 DOI: 10.3390/metabo12121239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/01/2022] [Accepted: 12/04/2022] [Indexed: 12/13/2022] Open
Abstract
Determining the locations of proteins within the eye thought to be involved in ocular pathogenesis is important to determine how best to target them for therapeutic benefits. However, immunohistochemistry is limited by the availability and specificity of antibodies. Additionally, the perceived role of both essential and non-essential metals within ocular tissue has been at the forefront of age-related macular degeneration (AMD) pathology for decades, yet even key metals such as copper and zinc have yet to have their roles deconvoluted. Here, mass spectrometry imaging (MSI) is employed to identify and spatially characterize both proteomic and metallomic species within ocular tissue to advance the application of a multiomic imaging methodology for the investigation of ocular diseases.
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11
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Martínez-Gil N, Maneu V, Kutsyr O, Fernández-Sánchez L, Sánchez-Sáez X, Sánchez-Castillo C, Campello L, Lax P, Pinilla I, Cuenca N. Cellular and molecular alterations in neurons and glial cells in inherited retinal degeneration. Front Neuroanat 2022; 16:984052. [PMID: 36225228 PMCID: PMC9548552 DOI: 10.3389/fnana.2022.984052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 08/29/2022] [Indexed: 11/19/2022] Open
Abstract
Multiple gene mutations have been associated with inherited retinal dystrophies (IRDs). Despite the spectrum of phenotypes caused by the distinct mutations, IRDs display common physiopathology features. Cell death is accompanied by inflammation and oxidative stress. The vertebrate retina has several attributes that make this tissue vulnerable to oxidative and nitrosative imbalance. The high energy demands and active metabolism in retinal cells, as well as their continuous exposure to high oxygen levels and light-induced stress, reveal the importance of tightly regulated homeostatic processes to maintain retinal function, which are compromised in pathological conditions. In addition, the subsequent microglial activation and gliosis, which triggers the secretion of pro-inflammatory cytokines, chemokines, trophic factors, and other molecules, further worsen the degenerative process. As the disease evolves, retinal cells change their morphology and function. In disease stages where photoreceptors are lost, the remaining neurons of the retina to preserve their function seek out for new synaptic partners, which leads to a cascade of morphological alterations in retinal cells that results in a complete remodeling of the tissue. In this review, we describe important molecular and morphological changes in retinal cells that occur in response to oxidative stress and the inflammatory processes underlying IRDs.
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Affiliation(s)
- Natalia Martínez-Gil
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Victoria Maneu
- Department of Optics, Pharmacology and Anatomy, University of Alicante, Alicante, Spain
| | - Oksana Kutsyr
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | | | - Xavier Sánchez-Sáez
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Carla Sánchez-Castillo
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Laura Campello
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
| | - Pedro Lax
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
- Alicante Institute for Health and Biomedical Research (ISABIAL), Alicante, Spain
| | - Isabel Pinilla
- Aragón Institute for Health Research (IIS Aragón), Zaragoza, Spain
- Department of Ophthalmology, Lozano Blesa University Hospital, Zaragoza, Spain
- Department of Surgery, University of Zaragoza, Zaragoza, Spain
- Isabel Pinilla,
| | - Nicolás Cuenca
- Department of Physiology, Genetics and Microbiology, University of Alicante, Alicante, Spain
- Alicante Institute for Health and Biomedical Research (ISABIAL), Alicante, Spain
- Institute Ramón Margalef, University of Alicante, Alicante, Spain
- *Correspondence: Nicolás Cuenca,
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12
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Ademi M, Yang X, Coleman MP, Gilley J. Natural variants of human SARM1 cause both intrinsic and dominant loss-of-function influencing axon survival. Sci Rep 2022; 12:13846. [PMID: 35974060 PMCID: PMC9381744 DOI: 10.1038/s41598-022-18052-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 08/04/2022] [Indexed: 11/08/2022] Open
Abstract
SARM1 is a central executioner of programmed axon death, and this role requires intrinsic NAD(P)ase or related enzyme activity. A complete absence of SARM1 robustly blocks axon degeneration in mice, but even a partial depletion confers meaningful protection. Since axon loss contributes substantially to the onset and progression of multiple neurodegenerative disorders, lower inherent SARM1 activity is expected to reduce disease susceptibility in some situations. We, therefore, investigated whether there are naturally occurring SARM1 alleles within the human population that encode SARM1 variants with loss-of-function. Out of the 18 natural SARM1 coding variants we selected as candidates, we found that 10 display loss-of-function in three complimentary assays: they fail to robustly deplete NAD in transfected HEK 293T cells; they lack constitutive and NMN-induced NADase activity; and they fail to promote axon degeneration in primary neuronal cultures. Two of these variants are also able to block axon degeneration in primary culture neurons in the presence of endogenous, wild-type SARM1, indicative of dominant loss-of-function. These results demonstrate that SARM1 loss-of-function variants occur naturally in the human population, and we propose that carriers of these alleles will have different degrees of reduced susceptibility to various neurological conditions.
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Affiliation(s)
- Mirlinda Ademi
- Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Forvie Site, Robinson Way, Cambridge, CB2 0PY, UK
| | - Xiuna Yang
- Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Forvie Site, Robinson Way, Cambridge, CB2 0PY, UK
| | - Michael P Coleman
- Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Forvie Site, Robinson Way, Cambridge, CB2 0PY, UK.
| | - Jonathan Gilley
- Department of Clinical Neurosciences, John van Geest Centre for Brain Repair, University of Cambridge, Forvie Site, Robinson Way, Cambridge, CB2 0PY, UK.
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13
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Brace EJ, Essuman K, Mao X, Palucki J, Sasaki Y, Milbrandt J, DiAntonio A. Distinct developmental and degenerative functions of SARM1 require NAD+ hydrolase activity. PLoS Genet 2022; 18:e1010246. [PMID: 35737728 PMCID: PMC9223315 DOI: 10.1371/journal.pgen.1010246] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 05/10/2022] [Indexed: 11/25/2022] Open
Abstract
SARM1 is the founding member of the TIR-domain family of NAD+ hydrolases and the central executioner of pathological axon degeneration. SARM1-dependent degeneration requires NAD+ hydrolysis. Prior to the discovery that SARM1 is an enzyme, SARM1 was studied as a TIR-domain adaptor protein with non-degenerative signaling roles in innate immunity and invertebrate neurodevelopment, including at the Drosophila neuromuscular junction (NMJ). Here we explore whether the NADase activity of SARM1 also contributes to developmental signaling. We developed transgenic Drosophila lines that express SARM1 variants with normal, deficient, and enhanced NADase activity and tested their function in NMJ development. We find that NMJ overgrowth scales with the amount of NADase activity, suggesting an instructive role for NAD+ hydrolysis in this developmental signaling pathway. While degenerative and developmental SARM1 signaling share a requirement for NAD+ hydrolysis, we demonstrate that these signals use distinct upstream and downstream mechanisms. These results identify SARM1-dependent NAD+ hydrolysis as a heretofore unappreciated component of developmental signaling. SARM1 now joins sirtuins and Parps as enzymes that regulate signal transduction pathways via mechanisms that involve NAD+ cleavage, greatly expanding the potential scope of SARM1 TIR NADase functions. SARM1 is the central executioner of axon loss, and inhibition of SARM1 is a therapeutic target for many devastating neurodegenerative disorders. SARM1 is the founding member of the TIR-domain family of NAD+ cleaving enzymes, destroying the essential metabolite NAD+ and inducing an energetic crisis in the axon. This was a surprising finding, as previously studied TIR-domain proteins were characterized as scaffolds that bind signaling proteins to coordinate signal transduction cascades. Indeed, before the discovery of the role of SARM1 in axon degeneration, SARM1 was studied as a regulator of intracellular signaling in immunity and neurodevelopment where it was assumed to act as a scaffold. Here we investigate whether the recently described SARM1 enzymatic activity also regulates such signal transduction pathways. Indeed, we show that a developmental signaling pathway scales with the amount of NADase activity, suggesting an instructive role for NAD+ cleavage. While degenerative and developmental SARM1 signaling share a requirement for NAD+ cleavage, they utilize distinct upstream and downstream mechanisms. With these findings, SARM1 now joins sirtuins and Parps as enzymes that regulate signal transduction pathways via mechanisms that involve NAD+ cleavage, greatly expanding the potential scope of SARM1 TIR NADase functions.
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Affiliation(s)
- E J Brace
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Kow Essuman
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Xianrong Mao
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - John Palucki
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Yo Sasaki
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Jeff Milbrandt
- Department of Genetics, Washington University School of Medicine, St. Louis, Missouri, United States of America.,Needleman Center for Neurometabolism and Axonal Therapeutics, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Aaron DiAntonio
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America.,Needleman Center for Neurometabolism and Axonal Therapeutics, Washington University School of Medicine, St. Louis, Missouri, United States of America
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14
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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: 0.5] [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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15
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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: 0] [Impact Index Per Article: 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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16
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Moss KR, Johnson AE, Bopp TS, Yu ATY, Perry K, Chung T, Höke A. SARM1 knockout does not rescue neuromuscular phenotypes in a Charcot-Marie-Tooth disease Type 1A mouse model. J Peripher Nerv Syst 2022; 27:58-66. [PMID: 35137510 PMCID: PMC8940700 DOI: 10.1111/jns.12483] [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: 08/30/2021] [Revised: 01/25/2022] [Accepted: 02/02/2022] [Indexed: 11/28/2022]
Abstract
Charcot-Marie-Tooth disease Type 1A (CMT1A) is caused by duplication of the PMP22 gene and is the most common inherited peripheral neuropathy. Although CMT1A is a dysmyelinating peripheral neuropathy, secondary axon degeneration has been suggested to drive functional deficits in patients. Given that SARM1 knockout is a potent inhibitor of the programmed axon degeneration pathway, we asked whether SARM1 knockout rescues neuromuscular phenotypes in CMT1A model (C3-PMP) mice. CMT1A mice were bred with SARM1 knockout mice to generate CMT1A/SARM1-/- mice. A series of behavioral assays were employed to evaluate motor and sensorimotor function. Electrophysiological and histological studies of the tibial branch of the sciatic nerve were performed. Additionally, gastrocnemius and soleus muscle morphology were evaluated histologically. Although clear behavioral and electrophysiological deficits were observed in CMT1A model mice, genetic deletion of SARM1 conferred no significant improvement. Nerve morphometry revealed predominantly myelin deficits in CMT1A model mice and SARM1 knockout yielded no improvement in all nerve morphometry measures. Similarly, muscle morphometry deficits in CMT1A model mice were not improved by SARM1 knockout. Our findings demonstrate that programmed axon degeneration pathway inhibition does not provide therapeutic benefit in C3-PMP CMT1A model mice. Our results indicate that the clinical phenotypes observed in CMT1A mice are likely caused primarily by prolonged dysmyelination, motivate further investigation into mechanisms of dysmyelination in these mice and necessitate the development of improved CMT1A rodent models that recapitulate the secondary axon degeneration observed in patients.
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Affiliation(s)
- Kathryn R. Moss
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD
| | - Anna E. Johnson
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD
| | - Taylor S. Bopp
- Department of Physical Medicine and Rehabilitation, Johns Hopkins School of Medicine, Baltimore, MD
| | - Andrew T-Y. Yu
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD
| | - Ken Perry
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD
| | - Tae Chung
- Department of Physical Medicine and Rehabilitation, Johns Hopkins School of Medicine, Baltimore, MD
| | - Ahmet Höke
- Department of Neurology, Neuromuscular Division, Johns Hopkins School of Medicine, Baltimore, MD,Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD,Corresponding Author: Ahmet Höke MD, PhD, Johns Hopkins School of Medicine, 855 N. Wolfe St., Baltimore, MD 21205, Tel: 410-955-2227, Fax: 410-502-5459,
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17
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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: 0.5] [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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18
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Finnegan LK, Chadderton N, Kenna PF, Palfi A, Carty M, Bowie AG, Millington-Ward S, Farrar GJ. SARM1 Ablation Is Protective and Preserves Spatial Vision in an In Vivo Mouse Model of Retinal Ganglion Cell Degeneration. Int J Mol Sci 2022; 23:ijms23031606. [PMID: 35163535 PMCID: PMC8835928 DOI: 10.3390/ijms23031606] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 01/21/2022] [Accepted: 01/26/2022] [Indexed: 02/04/2023] Open
Abstract
The challenge of developing gene therapies for genetic forms of blindness is heightened by the heterogeneity of these conditions. However, mechanistic commonalities indicate key pathways that may be targeted in a gene-independent approach. Mitochondrial dysfunction and axon degeneration are common features of many neurodegenerative conditions including retinal degenerations. Here we explore the neuroprotective effect afforded by the absence of sterile alpha and Toll/interleukin-1 receptor motif-containing 1 (SARM1), a prodegenerative NADase, in a rotenone-induced mouse model of retinal ganglion cell loss and visual dysfunction. Sarm1 knockout mice retain visual function after rotenone insult, displaying preservation of photopic negative response following rotenone treatment in addition to significantly higher optokinetic response measurements than wild type mice following rotenone. Protection of spatial vision is sustained over time in both sexes and is accompanied by increased RGC survival and additionally preservation of axonal density in optic nerves of Sarm1−/− mice insulted with rotenone. Primary fibroblasts extracted from Sarm1−/− mice demonstrate an increased oxygen consumption rate relative to those from wild type mice, with significantly higher basal, maximal and spare respiratory capacity. Collectively, our data indicate that Sarm1 ablation increases mitochondrial bioenergetics and confers histological and functional protection in vivo in the mouse retina against mitochondrial dysfunction, a hallmark of many neurodegenerative conditions including a variety of ocular disorders.
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Affiliation(s)
- Laura K. Finnegan
- Department of Genetics, The School of Genetics and Microbiology, Trinity College Dublin, D02 VF25 Dublin, Ireland; (N.C.); (P.F.K.); (A.P.); (S.M.-W.); (G.J.F.)
- Correspondence:
| | - Naomi Chadderton
- Department of Genetics, The School of Genetics and Microbiology, Trinity College Dublin, D02 VF25 Dublin, Ireland; (N.C.); (P.F.K.); (A.P.); (S.M.-W.); (G.J.F.)
| | - Paul F. Kenna
- Department of Genetics, The School of Genetics and Microbiology, Trinity College Dublin, D02 VF25 Dublin, Ireland; (N.C.); (P.F.K.); (A.P.); (S.M.-W.); (G.J.F.)
- The Research Foundation, Royal Victoria Eye and Ear Hospital, D02 XK51 Dublin, Ireland
| | - Arpad Palfi
- Department of Genetics, The School of Genetics and Microbiology, Trinity College Dublin, D02 VF25 Dublin, Ireland; (N.C.); (P.F.K.); (A.P.); (S.M.-W.); (G.J.F.)
| | - Michael Carty
- Trinity Biomedical Sciences Institute, The School of Biochemistry and Immunology, Trinity College Dublin, D02 R590 Dublin, Ireland; (M.C.); (A.G.B.)
| | - Andrew G. Bowie
- Trinity Biomedical Sciences Institute, The School of Biochemistry and Immunology, Trinity College Dublin, D02 R590 Dublin, Ireland; (M.C.); (A.G.B.)
| | - Sophia Millington-Ward
- Department of Genetics, The School of Genetics and Microbiology, Trinity College Dublin, D02 VF25 Dublin, Ireland; (N.C.); (P.F.K.); (A.P.); (S.M.-W.); (G.J.F.)
| | - G. Jane Farrar
- Department of Genetics, The School of Genetics and Microbiology, Trinity College Dublin, D02 VF25 Dublin, Ireland; (N.C.); (P.F.K.); (A.P.); (S.M.-W.); (G.J.F.)
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19
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Kayazawa T, Kuniyoshi K, Hatsukawa Y, Fujinami K, Yoshitake K, Tsunoda K, Shimojo H, Iwata T, Kusaka S. Clinical course of a Japanese girl with Leber congenital amaurosis associated with a novel nonsense pathogenic variant in NMNAT1: a case report and mini review. Ophthalmic Genet 2022; 43:400-408. [PMID: 35026968 DOI: 10.1080/13816810.2021.2023195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Leber congenital amaurosis (LCA), although rare, is one of the most severe forms of early-onset inherited retinal dystrophy (IRD). Here, we review the molecular genetics and phenotypic characteristics of patients with NMNAT1-associated IRD. The longitudinal clinical and molecular findings of a Japanese girl diagnosed with LCA associated with pathogenic variants in NMNAT1 c.648delG, (p.Trp216Ter*) and c.709C>T (p.Arg237Cys) have been described to highlight the salient clinical features of NMNAT1-associated IRD.
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Affiliation(s)
- Tomoyasu Kayazawa
- Department of Ophthalmology, Kindai University Faculty of Medicine, Osaka, Japan
| | - Kazuki Kuniyoshi
- Department of Ophthalmology, Kindai University Faculty of Medicine, Osaka, Japan
| | - Yoshikazu Hatsukawa
- Department of Ophthalmology, Osaka Women's and Children's Hospital, Osaka, Japan
| | - Kaoru Fujinami
- Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.,Genetics, UCL Institute of Ophthalmology Associated with Moorfields Eye Hospital, London, UK.,Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
| | - Kazutoshi Yoshitake
- Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.,Graduate School of Agricultural and Life Science, Faculty of Agriculture, The University of Tokyo, Tokyo, Japan
| | - Kazushige Tsunoda
- Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - Hiroshi Shimojo
- Department of Ophthalmology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Takeshi Iwata
- Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - Shunji Kusaka
- Department of Ophthalmology, Kindai University Faculty of Medicine, Osaka, Japan
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20
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Bloom AJ, Mao X, Strickland A, Sasaki Y, Milbrandt J, DiAntonio A. Constitutively active SARM1 variants that induce neuropathy are enriched in ALS patients. Mol Neurodegener 2022; 17:1. [PMID: 34991663 PMCID: PMC8739729 DOI: 10.1186/s13024-021-00511-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 12/17/2021] [Indexed: 03/31/2023] Open
Abstract
Background In response to injury, neurons activate a program of organized axon self-destruction initiated by the NAD+ hydrolase, SARM1. In healthy neurons SARM1 is autoinhibited, but single amino acid changes can abolish autoinhibition leading to constitutively active SARM1 enzymes that promote degeneration when expressed in cultured neurons. Methods To investigate whether naturally occurring human variants might disrupt SARM1 autoinhibition and potentially contribute to risk for neurodegenerative disease, we assayed the enzymatic activity of all 42 rare SARM1 alleles identified among 8507 amyotrophic lateral sclerosis (ALS) patients and 9671 controls. We then intrathecally injected mice with virus expressing SARM1 constructs to test the capacity of an ALS-associated constitutively active SARM1 variant to promote neurodegeneration in vivo. Results Twelve out of 42 SARM1 missense variants or small in-frame deletions assayed exhibit constitutive NADase activity, including more than half of those that are unique to the ALS patients or that occur in multiple patients. There is a > 5-fold enrichment of constitutively active variants among patients compared to controls. Expression of constitutively active ALS-associated SARM1 alleles in cultured dorsal root ganglion (DRG) neurons is pro-degenerative and cytotoxic. Intrathecal injection of an AAV expressing the common SARM1 reference allele is innocuous to mice, but a construct harboring SARM1V184G, the constitutively active variant found most frequently among the ALS patients, causes axon loss, motor dysfunction, and sustained neuroinflammation. Conclusions These results implicate rare hypermorphic SARM1 alleles as candidate genetic risk factors for ALS and other neurodegenerative conditions. Supplementary Information The online version contains supplementary material available at 10.1186/s13024-021-00511-x.
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Affiliation(s)
- A Joseph Bloom
- Needleman Center for Neurometabolism and Axonal Therapeutics and Department of Genetics, Washington University School of Medicine in Saint Louis, St. Louis, MO, USA.
| | - Xianrong Mao
- Needleman Center for Neurometabolism and Axonal Therapeutics and Department of Genetics, Washington University School of Medicine in Saint Louis, St. Louis, MO, USA
| | - Amy Strickland
- Needleman Center for Neurometabolism and Axonal Therapeutics and Department of Genetics, Washington University School of Medicine in Saint Louis, St. Louis, MO, USA
| | - Yo Sasaki
- Needleman Center for Neurometabolism and Axonal Therapeutics and Department of Genetics, Washington University School of Medicine in Saint Louis, St. Louis, MO, USA
| | - Jeffrey Milbrandt
- Needleman Center for Neurometabolism and Axonal Therapeutics and Department of Genetics, Washington University School of Medicine in Saint Louis, St. Louis, MO, USA.
| | - Aaron DiAntonio
- Needleman Center for Neurometabolism and Axonal Therapeutics and Department of Developmental Biology, Washington University School of Medicine in Saint Louis, St. Louis, MO, USA.
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21
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Ozaki E, Delaney C, Campbell M, Doyle SL. Minocycline suppresses disease-associated microglia (DAM) in a model of photoreceptor cell degeneration. Exp Eye Res 2022; 217:108953. [DOI: 10.1016/j.exer.2022.108953] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 01/10/2022] [Accepted: 01/14/2022] [Indexed: 11/04/2022]
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22
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Gilley J, Jackson O, Pipis M, Estiar MA, Al-Chalabi A, Danzi MC, van Eijk KR, Goutman SA, Harms MB, Houlden H, Iacoangeli A, Kaye J, Lima L, Ravits J, Rouleau GA, Schüle R, Xu J, Züchner S, Cooper-Knock J, Gan-Or Z, Reilly MM, Coleman MP. Enrichment of SARM1 alleles encoding variants with constitutively hyperactive NADase in patients with ALS and other motor nerve disorders. eLife 2021; 10:e70905. [PMID: 34796871 PMCID: PMC8735862 DOI: 10.7554/elife.70905] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 11/18/2021] [Indexed: 11/13/2022] Open
Abstract
SARM1, a protein with critical NADase activity, is a central executioner in a conserved programme of axon degeneration. We report seven rare missense or in-frame microdeletion human SARM1 variant alleles in patients with amyotrophic lateral sclerosis (ALS) or other motor nerve disorders that alter the SARM1 auto-inhibitory ARM domain and constitutively hyperactivate SARM1 NADase activity. The constitutive NADase activity of these seven variants is similar to that of SARM1 lacking the entire ARM domain and greatly exceeds the activity of wild-type SARM1, even in the presence of nicotinamide mononucleotide (NMN), its physiological activator. This rise in constitutive activity alone is enough to promote neuronal degeneration in response to otherwise non-harmful, mild stress. Importantly, these strong gain-of-function alleles are completely patient-specific in the cohorts studied and show a highly significant association with disease at the single gene level. These findings of disease-associated coding variants that alter SARM1 function build on previously reported genome-wide significant association with ALS for a neighbouring, more common SARM1 intragenic single nucleotide polymorphism (SNP) to support a contributory role of SARM1 in these disorders. A broad phenotypic heterogeneity and variable age-of-onset of disease among patients with these alleles also raises intriguing questions about the pathogenic mechanism of hyperactive SARM1 variants.
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Affiliation(s)
- Jonathan Gilley
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of CambridgeCambridgeUnited Kingdom
| | - Oscar Jackson
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of CambridgeCambridgeUnited Kingdom
| | - Menelaos Pipis
- Department of Neuromuscular Disease, UCL Queen Square Institute of Neurology and The National Hospital for NeurologyLondonUnited Kingdom
| | - Mehrdad A Estiar
- Department of Human Genetics, McGill UniversityMontrealCanada
- The Neuro (Montreal Neurological Institute-Hospital), McGill UniversityMontrealCanada
| | - Ammar Al-Chalabi
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King’s College LondonLondonUnited Kingdom
- Department of Neurology, King's College Hospital, King’s College LondonLondonUnited Kingdom
| | - Matt C Danzi
- Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami Miller School of MedicineMiamiUnited States
| | - Kristel R van Eijk
- Department of Neurology, UMC Utrecht Brain Center, University Medical Center Utrecht, Utrecht UniversityUtrechtNetherlands
| | - Stephen A Goutman
- Department of Neurology, University of MichiganAnn ArborUnited States
| | - Matthew B Harms
- Institute for Genomic Medicine, Columbia UniversityNew YorkUnited States
| | - Henry Houlden
- Department of Neuromuscular Disease, UCL Queen Square Institute of Neurology and The National Hospital for NeurologyLondonUnited Kingdom
| | - Alfredo Iacoangeli
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King’s College LondonLondonUnited Kingdom
- Department of Biostatistics and Health Informatics, Institute of Psychiatry, Psychology & Neuroscience, King's College LondonLondonUnited Kingdom
- National Institute for Health Research Biomedical Research Centre and Dementia Unit at South London and Maudsley NHS Foundation Trust and King's College LondonLondonUnited Kingdom
| | - Julia Kaye
- Center for Systems and Therapeutics, Gladstone InstitutesSan FranciscoUnited States
| | - Leandro Lima
- Center for Systems and Therapeutics, Gladstone InstitutesSan FranciscoUnited States
- Gladstone Institute of Data Science and Biotechnology, Gladstone InstitutesSan FranciscoUnited States
| | - Queen Square Genomics
- Department of Neuromuscular Disease, UCL Queen Square Institute of Neurology and The National Hospital for NeurologyLondonUnited Kingdom
| | - John Ravits
- Department of Neurosciences, University of California, San DiegoLa JollaUnited States
| | - Guy A Rouleau
- Department of Human Genetics, McGill UniversityMontrealCanada
- The Neuro (Montreal Neurological Institute-Hospital), McGill UniversityMontrealCanada
- Department of Neurology and Neurosurgery, McGill UniversityMontrealCanada
| | - Rebecca Schüle
- Center for Neurology and Hertie Institute für Clinical Brain Research, University of Tübingen, German Center for Neurodegenerative DiseasesTübingenGermany
| | - Jishu Xu
- Center for Neurology and Hertie Institute für Clinical Brain Research, University of Tübingen, German Center for Neurodegenerative DiseasesTübingenGermany
| | - Stephan Züchner
- Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami Miller School of MedicineMiamiUnited States
| | - Johnathan Cooper-Knock
- Sheffield Institute for Translational Neuroscience, University of SheffieldSheffieldUnited Kingdom
| | - Ziv Gan-Or
- Department of Human Genetics, McGill UniversityMontrealCanada
- The Neuro (Montreal Neurological Institute-Hospital), McGill UniversityMontrealCanada
- Department of Neurology and Neurosurgery, McGill UniversityMontrealCanada
| | - Mary M Reilly
- Department of Neuromuscular Disease, UCL Queen Square Institute of Neurology and The National Hospital for NeurologyLondonUnited Kingdom
| | - Michael P Coleman
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of CambridgeCambridgeUnited Kingdom
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23
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Ko KW, Devault L, Sasaki Y, Milbrandt J, DiAntonio A. Live imaging reveals the cellular events downstream of SARM1 activation. eLife 2021; 10:e71148. [PMID: 34779400 PMCID: PMC8612704 DOI: 10.7554/elife.71148] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 11/12/2021] [Indexed: 12/15/2022] Open
Abstract
SARM1 is an inducible NAD+ hydrolase that triggers axon loss and neuronal cell death in the injured and diseased nervous system. While SARM1 activation and enzyme function are well defined, the cellular events downstream of SARM1 activity but prior to axonal demise are much less well understood. Defects in calcium, mitochondria, ATP, and membrane homeostasis occur in injured axons, but the relationships among these events have been difficult to disentangle because prior studies analyzed large collections of axons in which cellular events occur asynchronously. Here, we used live imaging of mouse sensory neurons with single axon resolution to investigate the cellular events downstream of SARM1 activity. Our studies support a model in which SARM1 NADase activity leads to an ordered sequence of events from loss of cellular ATP, to defects in mitochondrial movement and depolarization, followed by calcium influx, externalization of phosphatidylserine, and loss of membrane permeability prior to catastrophic axonal self-destruction.
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Affiliation(s)
- Kwang Woo Ko
- Washington University School of MedicineSt LouisUnited States
| | - Laura Devault
- Washington University School of MedicineSt LouisUnited States
| | - Yo Sasaki
- Genetics, Washington University School of MedicineSt LouisUnited States
| | - Jeffrey Milbrandt
- Genetics, Hope Center for Neurological Disorders, Washington University School of MedicineSt LouisUnited States
| | - Aaron DiAntonio
- Developmental Biology, Needleman Center for Neurometabolism and Axonal Therapeutics, Washington University School of MedicineSt LouisUnited States
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24
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Sasaki Y, Zhu J, Shi Y, Gu W, Kobe B, Ve T, DiAntonio A, Milbrandt J. Nicotinic acid mononucleotide is an allosteric SARM1 inhibitor promoting axonal protection. Exp Neurol 2021; 345:113842. [PMID: 34403688 PMCID: PMC8571713 DOI: 10.1016/j.expneurol.2021.113842] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/09/2021] [Accepted: 08/12/2021] [Indexed: 12/31/2022]
Abstract
SARM1 is an inducible NAD+ hydrolase that is the central executioner of pathological axon loss. Recently, we elucidated the molecular mechanism of SARM1 activation, demonstrating that SARM1 is a metabolic sensor regulated by the levels of NAD+ and its precursor, nicotinamide mononucleotide (NMN), via their competitive binding to an allosteric site within the SARM1 N-terminal ARM domain. In healthy neurons with abundant NAD+, binding of NAD+ blocks access of NMN to this allosteric site. However, with injury or disease the levels of the NAD+ biosynthetic enzyme NMNAT2 drop, increasing the NMN/ NAD+ ratio and thereby promoting NMN binding to the SARM1 allosteric site, which in turn induces a conformational change activating the SARM1 NAD+ hydrolase. Hence, NAD+ metabolites both regulate the activation of SARM1 and, in turn, are regulated by the SARM1 NAD+ hydrolase. This dual upstream and downstream role for NAD+ metabolites in SARM1 function has hindered mechanistic understanding of axoprotective mechanisms that manipulate the NAD+ metabolome. Here we reevaluate two methods that potently block axon degeneration via modulation of NAD+ related metabolites, 1) the administration of the NMN biosynthesis inhibitor FK866 in conjunction with the NAD+ precursor nicotinic acid riboside (NaR) and 2) the neuronal expression of the bacterial enzyme NMN deamidase. We find that these approaches not only lead to a decrease in the levels of the SARM1 activator NMN, but also an increase in the levels of the NAD+ precursor nicotinic acid mononucleotide (NaMN). We show that NaMN inhibits SARM1 activation, and demonstrate that this NaMN-mediated inhibition is important for the long-term axon protection induced by these treatments. Analysis of the NaMN-ARM domain co-crystal structure shows that NaMN competes with NMN for binding to the SARM1 allosteric site and promotes the open, autoinhibited configuration of SARM1 ARM domain. Together, these results demonstrate that the SARM1 allosteric pocket can bind a diverse set of metabolites including NMN, NAD+, and NaMN to monitor cellular NAD+ homeostasis and regulate SARM1 NAD+ hydrolase activity. The relative promiscuity of the allosteric site may enable the development of potent pharmacological inhibitors of SARM1 activation for the treatment of neurodegenerative disorders.
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Affiliation(s)
- Yo Sasaki
- Washington University School of Medicine in Saint Louis, Department of Genetics, St. Louis, MO, USA; Needleman Center for Neurometabolism and Axonal Therapeutics, USA.
| | - Jian Zhu
- Washington University School of Medicine in Saint Louis, Department of Genetics, St. Louis, MO, USA; Needleman Center for Neurometabolism and Axonal Therapeutics, USA
| | - Yun Shi
- Institute for Glycomics, Griffith University, Southport, QLD 4222, Australia
| | - Weixi Gu
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, QLD 4072, Australia
| | - Bostjan Kobe
- School of Chemistry and Molecular Biosciences, Institute for Molecular Bioscience and Australian Infectious Diseases Research Centre, University of Queensland, QLD 4072, Australia
| | - Thomas Ve
- Institute for Glycomics, Griffith University, Southport, QLD 4222, Australia
| | - Aaron DiAntonio
- Washington University School of Medicine in Saint Louis, Department of Developmental Biology, St. Louis, MO, USA; Needleman Center for Neurometabolism and Axonal Therapeutics, USA
| | - Jeffrey Milbrandt
- Washington University School of Medicine in Saint Louis, Department of Genetics, St. Louis, MO, USA; Needleman Center for Neurometabolism and Axonal Therapeutics, USA
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25
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DiAntonio A, Milbrandt J, Figley MD. The SARM1 TIR NADase: Mechanistic Similarities to Bacterial Phage Defense and Toxin-Antitoxin Systems. Front Immunol 2021; 12:752898. [PMID: 34630431 PMCID: PMC8494770 DOI: 10.3389/fimmu.2021.752898] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 08/26/2021] [Indexed: 01/19/2023] Open
Abstract
The Toll/interleukin-1 receptor (TIR) domain is the signature signalling motif of innate immunity, with essential roles in innate immune signalling in bacteria, plants, and animals. TIR domains canonically function as scaffolds, with stimulus-dependent multimerization generating binding sites for signalling molecules such as kinases and ligases that activate downstream immune mechanisms. Recent studies have dramatically expanded our understanding of the TIR domain, demonstrating that the primordial function of the TIR domain is to metabolize NAD+. Mammalian SARM1, the central executioner of pathological axon degeneration, is the founding member of the TIR-domain class of NAD+ hydrolases. This unexpected NADase activity of TIR domains is evolutionarily conserved, with archaeal, bacterial, and plant TIR domains all sharing this catalytic function. Moreover, this enzymatic activity is essential for the innate immune function of these proteins. These evolutionary relationships suggest a link between SARM1 and ancient self-defense mechanisms that has only been strengthened by the recent discovery of the SARM1 activation mechanism which, we will argue, is strikingly similar to bacterial toxin-antitoxin systems. In this brief review we will describe the regulation and function of SARM1 in programmed axon self-destruction, and highlight the parallels between the SARM1 axon degeneration pathway and bacterial innate immune mechanisms.
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Affiliation(s)
- Aaron DiAntonio
- Department of Developmental Biology, Washington University School of Medicine in Saint Louis, St. Louis, MO, United States
- Needleman Center for Neurometabolism and Axonal Therapeutics, Washington University School of Medicine in Saint Louis, St. Louis, MO, United States
| | - Jeffrey Milbrandt
- Needleman Center for Neurometabolism and Axonal Therapeutics, Washington University School of Medicine in Saint Louis, St. Louis, MO, United States
- Department of Genetics, Washington University School of Medicine in Saint Louis, St. Louis, MO, United States
| | - Matthew D Figley
- Department of Developmental Biology, Washington University School of Medicine in Saint Louis, St. Louis, MO, United States
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26
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Abstract
Axon degeneration is an active program of self-destruction mediated by the protein SARM1. In healthy neurons, SARM1 is autoinhibited and, upon injury autoinhibition is relieved, activating the SARM1 enzyme to deplete NAD+ and induce axon degeneration. SARM1 forms a homomultimeric octamer with each monomer composed of an N-terminal autoinhibitory ARM domain, tandem SAM domains that mediate multimerization, and a C-terminal TIR domain encoding the NADase enzyme. Here we discovered multiple intramolecular and intermolecular domain interfaces required for SARM1 autoinhibition using peptide mapping and cryo-electron microscopy (cryo-EM). We identified a candidate autoinhibitory region by screening a panel of peptides derived from the SARM1 ARM domain, identifying a peptide mediating high-affinity inhibition of the SARM1 NADase. Mutation of residues in full-length SARM1 within the region encompassed by the peptide led to loss of autoinhibition, rendering SARM1 constitutively active and inducing spontaneous NAD+ and axon loss. The cryo-EM structure of SARM1 revealed 1) a compact autoinhibited SARM1 octamer in which the TIR domains are isolated and prevented from oligomerization and enzymatic activation and 2) multiple candidate autoinhibitory interfaces among the domains. Mutational analysis demonstrated that five distinct interfaces are required for autoinhibition, including intramolecular and intermolecular ARM-SAM interfaces, an intermolecular ARM-ARM interface, and two ARM-TIR interfaces formed between a single TIR and two distinct ARM domains. These autoinhibitory regions are not redundant, as point mutants in each led to constitutively active SARM1. These studies define the structural basis for SARM1 autoinhibition and may enable the development of SARM1 inhibitors that stabilize the autoinhibited state.
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27
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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: 7] [Impact Index Per Article: 2.3] [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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28
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Bosanac T, Hughes RO, Engber T, Devraj R, Brearley A, Danker K, Young K, Kopatz J, Hermann M, Berthemy A, Boyce S, Bentley J, Krauss R. Pharmacological SARM1 inhibition protects axon structure and function in paclitaxel-induced peripheral neuropathy. Brain 2021; 144:3226-3238. [PMID: 33964142 PMCID: PMC8634121 DOI: 10.1093/brain/awab184] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 03/02/2021] [Accepted: 04/27/2021] [Indexed: 11/26/2022] Open
Abstract
Axonal degeneration is an early and ongoing event that causes disability and disease progression in many neurodegenerative disorders of the peripheral and central nervous systems. Chemotherapy-induced peripheral neuropathy (CIPN) is a major cause of morbidity and the main cause of dose reductions and discontinuations in cancer treatment. Preclinical evidence indicates that activation of the Wallerian-like degeneration pathway driven by sterile alpha and TIR motif containing 1 (SARM1) is responsible for axonopathy in CIPN. SARM1 is the central driver of an evolutionarily conserved programme of axonal degeneration downstream of chemical, inflammatory, mechanical or metabolic insults to the axon. SARM1 contains an intrinsic NADase enzymatic activity essential for its pro-degenerative functions, making it a compelling therapeutic target to treat neurodegeneration characterized by axonopathies of the peripheral and central nervous systems. Small molecule SARM1 inhibitors have the potential to prevent axonal degeneration in peripheral and central axonopathies and to provide a transformational disease-modifying treatment for these disorders. Using a biochemical assay for SARM1 NADase we identified a novel series of potent and selective irreversible isothiazole inhibitors of SARM1 enzymatic activity that protected rodent and human axons in vitro. In sciatic nerve axotomy, we observed that these irreversible SARM1 inhibitors decreased a rise in nerve cADPR and plasma neurofilament light chain released from injured sciatic nerves in vivo. In a mouse paclitaxel model of CIPN we determined that Sarm1 knockout mice prevented loss of axonal function, assessed by sensory nerve action potential amplitudes of the tail nerve, in a gene-dosage-dependent manner. In that CIPN model, the irreversible SARM1 inhibitors prevented loss of intraepidermal nerve fibres induced by paclitaxel and provided partial protection of axonal function assessed by sensory nerve action potential amplitude and mechanical allodynia.
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Affiliation(s)
- Todd Bosanac
- Disarm Therapeutics, a wholly owned subsidiary of Eli Lilly & Co., Cambridge MA 02142, USA
| | - Robert O Hughes
- Disarm Therapeutics, a wholly owned subsidiary of Eli Lilly & Co., Cambridge MA 02142, USA
| | - Thomas Engber
- Disarm Therapeutics, a wholly owned subsidiary of Eli Lilly & Co., Cambridge MA 02142, USA
| | - Rajesh Devraj
- Disarm Therapeutics, a wholly owned subsidiary of Eli Lilly & Co., Cambridge MA 02142, USA
| | | | | | | | | | | | | | | | | | - Raul Krauss
- Disarm Therapeutics, a wholly owned subsidiary of Eli Lilly & Co., Cambridge MA 02142, USA
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29
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Perottoni S, Neto NGB, Di Nitto C, Dmitriev RI, Raimondi MT, Monaghan MG. Intracellular label-free detection of mesenchymal stem cell metabolism within a perivascular niche-on-a-chip. LAB ON A CHIP 2021; 21:1395-1408. [PMID: 33605282 DOI: 10.1039/d0lc01034k] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The stem cell niche at the perivascular space in human tissue plays a pivotal role in dictating the overall fate of stem cells within it. Mesenchymal stem cells (MSCs) in particular, experience influential microenvironmental conditions, which induce specific metabolic profiles that affect processes of cell differentiation and dysregulation of the immunomodulatory function. Reports focusing specifically on the metabolic status of MSCs under the effect of pathophysiological stimuli - in terms of flow velocities, shear stresses or oxygen tension - do not model heterogeneous gradients, highlighting the need for more advanced models reproducing the metabolic niche. Organ-on-a-chip technology offers the most advanced tools for stem cell niche modelling thus allowing for controlled dynamic culture conditions while profiling tuneable oxygen tension gradients. However, current systems for live cell detection of metabolic activity inside microfluidic devices require the integration of microsensors. The presence of such microsensors poses the potential to alter microfluidics and their resolution does not enable intracellular measurements but rather a global representation concerning cellular metabolism. Here, we present a metabolic toolbox coupling a miniaturised in vitro system for human-MSCs dynamic culture, which mimics microenvironmental conditions of the perivascular niche, with high-resolution imaging of cell metabolism. Using fluorescence lifetime imaging microscopy (FLIM) we monitor the spatial metabolic machinery and correlate it with experimentally validated intracellular oxygen concentration after designing the oxygen tension decay along the fluidic chamber by in silico models prediction. Our platform allows the metabolic regulation of MSCs, mimicking the physiological niche in space and time, and its real-time monitoring representing a functional tool for modelling perivascular niches, relevant diseases and metabolic-related uptake of pharmaceuticals.
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Affiliation(s)
- Simone Perottoni
- Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Piazza Leonardo da Vinci, 32 - 20133 Milan, Italy.
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30
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Photoreceptor metabolic reprogramming: current understanding and therapeutic implications. Commun Biol 2021; 4:245. [PMID: 33627778 PMCID: PMC7904922 DOI: 10.1038/s42003-021-01765-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 01/28/2021] [Indexed: 02/06/2023] Open
Abstract
Acquired and inherited retinal disorders are responsible for vision loss in an increasing proportion of individuals worldwide. Photoreceptor (PR) death is central to the vision loss individuals experience in these various retinal diseases. Unfortunately, there is a lack of treatment options to prevent PR loss, so an urgent unmet need exists for therapies that improve PR survival and ultimately, vision. The retina is one of the most energy demanding tissues in the body, and this is driven in large part by the metabolic needs of PRs. Recent studies suggest that disruption of nutrient availability and regulation of cell metabolism may be a unifying mechanism in PR death. Understanding retinal cell metabolism and how it is altered in disease has been identified as a priority area of research. The focus of this review is on the recent advances in the understanding of PR metabolism and how it is critical to reduction-oxidation (redox) balance, the outer retinal metabolic ecosystem, and retinal disease. The importance of these metabolic processes is just beginning to be realized and unraveling the metabolic and redox pathways integral to PR health may identify novel targets for neuroprotective strategies that prevent blindness in the heterogenous group of retinal disorders.
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31
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Chen YH, Sasaki Y, DiAntonio A, Milbrandt J. SARM1 is required in human derived sensory neurons for injury-induced and neurotoxic axon degeneration. Exp Neurol 2021; 339:113636. [PMID: 33548217 DOI: 10.1016/j.expneurol.2021.113636] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 01/12/2021] [Accepted: 01/31/2021] [Indexed: 11/16/2022]
Abstract
Axonal degeneration contributes to the pathogenesis of many neurodegenerative disorders, motivating efforts to dissect the mechanism of pathological axon loss in order to develop therapies for axonal preservation. SARM1 is a particularly attractive therapeutic target, as it is an inducible NAD+ cleaving enzyme that is required for axon loss in multiple mouse models of traumatic and degenerative neurological disease. However, it is essential to establish whether SARM1 triggers axon degeneration in human neurons before proceeding with the development of SARM1-directed therapeutics. Here we combine genome engineering with the production of human stem cell-derived neurons to test the role of human SARM1 in traumatic and neurotoxic axon degeneration. We have generated two independent SARM1 knockout human iPSC lines that do not express SARM1 protein upon differentiation into neurons. We have developed a modified sensory neuron differentiation protocol that generates human sensory neurons with high yield and purity. We find that SARM1 is required for axon degeneration in response to both physical trauma and in a cellular model of chemotherapy-induced peripheral neuropathy. Finally, we identify cADPR as a biomarker of SARM1 enzyme activity in both healthy and injured human sensory neurons. These findings are consistent with prior molecular and cellular studies in mouse neurons, and highlight the therapeutic potential of SARM1 inhibition for the prevention and treatment of human neurological disease.
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Affiliation(s)
- Yi-Hsien Chen
- Needleman Center for Neurometabolism and Axonal Therapeutics, Washington University School of Medicine, St. Louis, MO 63110, USA; Genome Engineering and iPSC Center, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Yo Sasaki
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Aaron DiAntonio
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA; Needleman Center for Neurometabolism and Axonal Therapeutics, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | - Jeffrey Milbrandt
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA; Needleman Center for Neurometabolism and Axonal Therapeutics, Washington University School of Medicine, St. Louis, MO 63110, USA.
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32
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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: 67] [Impact Index Per Article: 16.8] [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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33
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Sasaki Y, Kakita H, Kubota S, Sene A, Lee TJ, Ban N, Dong Z, Lin JB, Boye SL, DiAntonio A, Boye SE, Apte RS, Milbrandt J. SARM1 depletion rescues NMNAT1-dependent photoreceptor cell death and retinal degeneration. eLife 2020; 9:e62027. [PMID: 33107823 PMCID: PMC7591247 DOI: 10.7554/elife.62027] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [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: 10/13/2020] [Indexed: 01/02/2023] Open
Abstract
Leber congenital amaurosis type nine is an autosomal recessive retinopathy caused by mutations of the NAD+ synthesis enzyme NMNAT1. Despite the ubiquitous expression of NMNAT1, patients do not manifest pathologies other than retinal degeneration. Here we demonstrate that widespread NMNAT1 depletion in adult mice mirrors the human pathology, with selective loss of photoreceptors highlighting the exquisite vulnerability of these cells to NMNAT1 loss. Conditional deletion demonstrates that NMNAT1 is required within the photoreceptor. Mechanistically, loss of NMNAT1 activates the NADase SARM1, the central executioner of axon degeneration, to trigger photoreceptor death and vision loss. Hence, the essential function of NMNAT1 in photoreceptors is to inhibit SARM1, highlighting an unexpected shared mechanism between axonal degeneration and photoreceptor neurodegeneration. These results define a novel SARM1-dependent photoreceptor cell death pathway and identifies SARM1 as a therapeutic candidate for retinopathies.
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Affiliation(s)
- Yo Sasaki
- Department of Genetics, Washington University School of MedicineSt. LouisUnited States
| | - Hiroki Kakita
- Department of Genetics, Washington University School of MedicineSt. LouisUnited States
- Department of Perinatal and Neonatal Medicine, Aichi Medical UniversityAichiJapan
| | - Shunsuke Kubota
- Department of Ophthalmology and Visual Sciences, Washington University School of MedicineSt. LouisUnited States
| | - Abdoulaye Sene
- Department of Ophthalmology and Visual Sciences, Washington University School of MedicineSt. LouisUnited States
| | - Tae Jun Lee
- Department of Ophthalmology and Visual Sciences, Washington University School of MedicineSt. LouisUnited States
| | - Norimitsu Ban
- Department of Ophthalmology and Visual Sciences, Washington University School of MedicineSt. LouisUnited States
| | - Zhenyu Dong
- Department of Ophthalmology and Visual Sciences, Washington University School of MedicineSt. LouisUnited States
| | - Joseph B Lin
- Department of Ophthalmology and Visual Sciences, Washington University School of MedicineSt. LouisUnited States
| | - Sanford L Boye
- Department of Pediatrics, Powell Gene Therapy CenterGainesvilleUnited States
| | - Aaron DiAntonio
- Department of Developmental Biology, Washington University School of MedicineSt. LouisUnited States
- Needleman Center for Neurometabolism and Axonal TherapeuticsSt. LouisUnited States
| | - Shannon E Boye
- Department of Pediatrics, Division of Cellular and Molecular TherapyGainesvilleUnited States
| | - Rajendra S Apte
- Department of Ophthalmology and Visual Sciences, Washington University School of MedicineSt. LouisUnited States
- Department of Developmental Biology, Washington University School of MedicineSt. LouisUnited States
- Department of Medicine, Washington University School of MedicineSt. LouisUnited States
| | - Jeffrey Milbrandt
- Department of Genetics, Washington University School of MedicineSt. LouisUnited States
- Needleman Center for Neurometabolism and Axonal TherapeuticsSt. LouisUnited States
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Su X. Inhibiting the executioner may prevent vision loss. Sci Transl Med 2020. [DOI: 10.1126/scitranslmed.abb7094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
SARM1 plays a role in photoreceptor survival, and its inhibition presents an alternative way to treat retinal degenerative disease.
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Affiliation(s)
- Xinyi Su
- Department of Ophthalmology, National University of Singapore; Department of Ophthalmology, National University Hospital; Institute of Molecular and Cell Biology, A*STAR; Singapore Eye Research Institute; Singapore
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