1
|
Huo A, Wang J, Li Q, Li M, Qi Y, Yin Q, Luo W, Shi J, Cong Q. Molecular mechanisms underlying microglial sensing and phagocytosis in synaptic pruning. Neural Regen Res 2024; 19:1284-1290. [PMID: 37905877 DOI: 10.4103/1673-5374.385854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Accepted: 08/03/2023] [Indexed: 11/02/2023] Open
Abstract
ABSTRACT Microglia are the main non-neuronal cells in the central nervous system that have important roles in brain development and functional connectivity of neural circuits. In brain physiology, highly dynamic microglial processes are facilitated to sense the surrounding environment and stimuli. Once the brain switches its functional states, microglia are recruited to specific sites to exert their immune functions, including the release of cytokines and phagocytosis of cellular debris. The crosstalk of microglia between neurons, neural stem cells, endothelial cells, oligodendrocytes, and astrocytes contributes to their functions in synapse pruning, neurogenesis, vascularization, myelination, and blood-brain barrier permeability. In this review, we highlight the neuron-derived "find-me," "eat-me," and "don't eat-me" molecular signals that drive microglia in response to changes in neuronal activity for synapse refinement during brain development. This review reveals the molecular mechanism of neuron-microglia interaction in synaptic pruning and presents novel ideas for the synaptic pruning of microglia in disease, thereby providing important clues for discovery of target drugs and development of nervous system disease treatment methods targeting synaptic dysfunction.
Collapse
Affiliation(s)
- Anran Huo
- Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University; Institute of Neuroscience and Jiangsu Key Laboratory of Neuropsychiatric Diseases, Soochow University, Suzhou, Jiangsu Province, China
| | - Jiali Wang
- Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University; Institute of Neuroscience and Jiangsu Key Laboratory of Neuropsychiatric Diseases, Soochow University, Suzhou, Jiangsu Province, China
| | - Qi Li
- Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University; Institute of Neuroscience and Jiangsu Key Laboratory of Neuropsychiatric Diseases, Soochow University, Suzhou, Jiangsu Province, China
| | - Mengqi Li
- Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University; Institute of Neuroscience and Jiangsu Key Laboratory of Neuropsychiatric Diseases, Soochow University, Suzhou, Jiangsu Province, China
| | - Yuwan Qi
- Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University; Institute of Neuroscience and Jiangsu Key Laboratory of Neuropsychiatric Diseases, Soochow University, Suzhou, Jiangsu Province, China
| | - Qiao Yin
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Weifeng Luo
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Jijun Shi
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Qifei Cong
- Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University; Institute of Neuroscience and Jiangsu Key Laboratory of Neuropsychiatric Diseases, Soochow University, Suzhou, Jiangsu Province, China
| |
Collapse
|
2
|
Shui X, Chen J, Fu Z, Zhu H, Tao H, Li Z. Microglia in Ischemic Stroke: Pathogenesis Insights and Therapeutic Challenges. J Inflamm Res 2024; 17:3335-3352. [PMID: 38800598 PMCID: PMC11128258 DOI: 10.2147/jir.s461795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Accepted: 05/14/2024] [Indexed: 05/29/2024] Open
Abstract
Ischemic stroke is the most common type of stroke, which is the main cause of death and disability on a global scale. As the primary immune cells in the brain that are crucial for preserving homeostasis of the central nervous system microenvironment, microglia have been found to exhibit dual or even multiple effects at different stages of ischemic stroke. The anti-inflammatory polarization of microglia and release of neurotrophic factors may provide benefits by promoting neurological recovery at the lesion in the early phase after ischemic stroke. However, the pro-inflammatory polarization of microglia and secretion of inflammatory factors in the later phase of injury may exacerbate the ischemic lesion, suggesting the therapeutic potential of modulating the balance of microglial polarization to predispose them to anti-inflammatory transformation in ischemic stroke. Microglia-mediated signaling crosstalk with other cells may also be key to improving functional outcomes following ischemic stroke. Thus, this review provides an overview of microglial functions and responses under physiological and ischemic stroke conditions, including microglial activation, polarization, and interactions with other cells. We focus on approaches that promote anti-inflammatory polarization of microglia, inhibit microglial activation, and enhance beneficial cell-to-cell interactions. These targets may hold promise for the creation of innovative therapeutic strategies.
Collapse
Affiliation(s)
- Xinyao Shui
- Clinical Medical College, Southwest Medical University, Luzhou, People’s Republic of China
| | - Jingsong Chen
- Department of Laboratory Medicine, the Affiliated Hospital of Southwest Medical University, Luzhou, People’s Republic of China
- Sichuan Province Engineering Technology Research Center of Molecular Diagnosis of Clinical Diseases, Luzhou, People’s Republic of China
- Molecular Diagnosis of Clinical Diseases Key Laboratory of Luzhou, Luzhou, People’s Republic of China
| | - Ziyue Fu
- Clinical Medical College, Southwest Medical University, Luzhou, People’s Republic of China
| | - Haoyue Zhu
- Clinical Medical College, Southwest Medical University, Luzhou, People’s Republic of China
| | - Hualin Tao
- Department of Laboratory Medicine, the Affiliated Hospital of Southwest Medical University, Luzhou, People’s Republic of China
- Sichuan Province Engineering Technology Research Center of Molecular Diagnosis of Clinical Diseases, Luzhou, People’s Republic of China
- Molecular Diagnosis of Clinical Diseases Key Laboratory of Luzhou, Luzhou, People’s Republic of China
| | - Zhaoyinqian Li
- Department of Laboratory Medicine, the Affiliated Hospital of Southwest Medical University, Luzhou, People’s Republic of China
- Sichuan Province Engineering Technology Research Center of Molecular Diagnosis of Clinical Diseases, Luzhou, People’s Republic of China
- Molecular Diagnosis of Clinical Diseases Key Laboratory of Luzhou, Luzhou, People’s Republic of China
| |
Collapse
|
3
|
Xie L, Wu Q, Li K, S Khan MA, Zhang A, Sinha B, Li S, Chang SL, Brody DL, Grinstaff MW, Zhou S, Alterovitz G, Liu P, Wang X. Tryptophan Metabolism in Alzheimer's Disease with the Involvement of Microglia and Astrocyte Crosstalk and Gut-Brain Axis. Aging Dis 2024:AD.2024.0134. [PMID: 38916729 DOI: 10.14336/ad.2024.0134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 05/03/2024] [Indexed: 06/26/2024] Open
Abstract
Alzheimer's disease (AD) is an age-dependent neurodegenerative disease characterized by extracellular Amyloid Aβ peptide (Aβ) deposition and intracellular Tau protein aggregation. Glia, especially microglia and astrocytes are core participants during the progression of AD and these cells are the mediators of Aβ clearance and degradation. The microbiota-gut-brain axis (MGBA) is a complex interactive network between the gut and brain involved in neurodegeneration. MGBA affects the function of glia in the central nervous system (CNS), and microbial metabolites regulate the communication between astrocytes and microglia; however, whether such communication is part of AD pathophysiology remains unknown. One of the potential links in bilateral gut-brain communication is tryptophan (Trp) metabolism. The microbiota-originated Trp and its metabolites enter the CNS to control microglial activation, and the activated microglia subsequently affect astrocyte functions. The present review highlights the role of MGBA in AD pathology, especially the roles of Trp per se and its metabolism as a part of the gut microbiota and brain communications. We (i) discuss the roles of Trp derivatives in microglia-astrocyte crosstalk from a bioinformatics perspective, (ii) describe the role of glia polarization in the microglia-astrocyte crosstalk and AD pathology, and (iii) summarize the potential of Trp metabolism as a therapeutic target. Finally, we review the role of Trp in AD from the perspective of the gut-brain axis and microglia, as well as astrocyte crosstalk, to inspire the discovery of novel AD therapeutics.
Collapse
Affiliation(s)
- Lushuang Xie
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
- Acupuncture and Moxibustion College, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, 610075, China
| | - Qiaofeng Wu
- Acupuncture and Moxibustion College, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, 610075, China
| | - Kelin Li
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
- Department of Chemistry, Boston University, Boston, MA 02215, USA
| | - Mohammed A S Khan
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Andrew Zhang
- Biomedical Cybernetics Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Bharati Sinha
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Sihui Li
- Acupuncture and Moxibustion College, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, 610075, China
| | - Sulie L Chang
- Department of Biological Sciences, Institute of NeuroImmune Pharmacology, Seton Hall University, South Orange, NJ 07079, USA
| | - David L Brody
- Department of Neurology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Mark W Grinstaff
- Department of Chemistry, Boston University, Boston, MA 02215, USA
| | - Shuanhu Zhou
- Harvard Medical School, Harvard Stem Cell Institute, Boston, MA 02115, USA
| | - Gil Alterovitz
- Biomedical Cybernetics Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Pinghua Liu
- Department of Chemistry, Boston University, Boston, MA 02215, USA
| | - Xin Wang
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| |
Collapse
|
4
|
Wißfeld J, Abou Assale T, Cuevas-Rios G, Liao H, Neumann H. Therapeutic potential to target sialylation and SIGLECs in neurodegenerative and psychiatric diseases. Front Neurol 2024; 15:1330874. [PMID: 38529039 PMCID: PMC10961342 DOI: 10.3389/fneur.2024.1330874] [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: 10/31/2023] [Accepted: 02/21/2024] [Indexed: 03/27/2024] Open
Abstract
Sialic acids, commonly found as the terminal carbohydrate on the glycocalyx of mammalian cells, are pivotal checkpoint inhibitors of the innate immune system, particularly within the central nervous system (CNS). Sialic acid-binding immunoglobulin-like lectins (SIGLECs) expressed on microglia are key players in maintaining microglial homeostasis by recognizing intact sialylation. The finely balanced sialic acid-SIGLEC system ensures the prevention of excessive and detrimental immune responses in the CNS. However, loss of sialylation and SIGLEC receptor dysfunctions contribute to several chronic CNS diseases. Genetic variants of SIGLEC3/CD33, SIGLEC11, and SIGLEC14 have been associated with neurodegenerative diseases such as Alzheimer's disease, while sialyltransferase ST8SIA2 and SIGLEC4/MAG have been linked to psychiatric diseases such as schizophrenia, bipolar disorders, and autism spectrum disorders. Consequently, immune-modulatory functions of polysialic acids and SIGLEC binding antibodies have been exploited experimentally in animal models of Alzheimer's disease and inflammation-induced CNS tissue damage, including retinal damage. While the potential of these therapeutic approaches is evident, only a few therapies to target either sialylation or SIGLEC receptors have been tested in patient clinical trials. Here, we provide an overview of the critical role played by the sialic acid-SIGLEC axis in shaping microglial activation and function within the context of neurodegeneration and synaptopathies and discuss the current landscape of therapies that target sialylation or SIGLECs.
Collapse
Affiliation(s)
- Jannis Wißfeld
- Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital Bonn, University of Bonn, Bonn, Germany
| | - Tawfik Abou Assale
- Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital Bonn, University of Bonn, Bonn, Germany
| | - German Cuevas-Rios
- Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital Bonn, University of Bonn, Bonn, Germany
| | - Huan Liao
- Florey Institute of Neuroscience and Mental Health, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Harald Neumann
- Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital Bonn, University of Bonn, Bonn, Germany
| |
Collapse
|
5
|
Bocharova O, Makarava N, Pandit NP, Molesworth K, Baskakov IV. Multiple steps of prion strain adaptation to a new host. Front Neurosci 2024; 18:1329010. [PMID: 38362022 PMCID: PMC10867973 DOI: 10.3389/fnins.2024.1329010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 01/12/2024] [Indexed: 02/17/2024] Open
Abstract
The transmission of prions across species is a critical aspect of their dissemination among mammalian hosts, including humans. This process often necessitates strain adaptation. In this study, we sought to investigate the mechanisms underlying prion adaptation while mitigating biases associated with the history of cross-species transmission of natural prion strains. To achieve this, we utilized the synthetic hamster prion strain S05. Propagation of S05 using mouse PrPC in Protein Misfolding Cyclic Amplification did not immediately overcome the species barrier. This finding underscores the involvement of factors beyond disparities in primary protein structures. Subsequently, we performed five serial passages to stabilize the incubation time to disease in mice. The levels of PrPSc increased with each passage, reaching a maximum at the third passage, and declining thereafter. This suggests that only the initial stage of adaptation is primarily driven by an acceleration in PrPSc replication. During the protracted adaptation to a new host, we observed significant alterations in the glycoform ratio and sialylation status of PrPSc N-glycans. These changes support the notion that qualitative modifications in PrPSc contribute to a more rapid disease progression. Furthermore, consistent with the decline in sialylation, a cue for "eat me" signaling, the newly adapted strain exhibited preferential colocalization with microglia. In contrast to PrPSc dynamics, the intensity of microglia activation continued to increase after the third passage in the new host. In summary, our study elucidates that the adaptation of a prion strain to a new host is a multi-step process driven by several factors.
Collapse
Affiliation(s)
- Olga Bocharova
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Natallia Makarava
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Narayan P. Pandit
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Kara Molesworth
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Ilia V. Baskakov
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, MD, United States
| |
Collapse
|
6
|
Delaveris C, Wang CL, Riley NM, Li S, Kulkarni RU, Bertozzi CR. Microglia Mediate Contact-Independent Neuronal Network Remodeling via Secreted Neuraminidase-3 Associated with Extracellular Vesicles. ACS CENTRAL SCIENCE 2023; 9:2108-2114. [PMID: 38033791 PMCID: PMC10683476 DOI: 10.1021/acscentsci.3c01066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 10/06/2023] [Accepted: 10/10/2023] [Indexed: 12/02/2023]
Abstract
Neurons communicate with each other through electrochemical transmission at synapses. Microglia, the resident immune cells of the central nervous system, modulate this communication through a variety of contact-dependent and -independent means. Microglial secretion of active sialidase enzymes upon exposure to inflammatory stimuli is one unexplored mechanism of modulation. Recent work from our lab showed that treatment of neurons with bacterial sialidases disrupts neuronal network connectivity. Here, we find that activated microglia secrete neuraminidase-3 (Neu3) associated with fusogenic extracellular vesicles. Furthermore, we show that Neu3 mediates contact-independent disruption of neuronal network synchronicity through neuronal glycocalyx remodeling. We observe that NEU3 is transcriptionally upregulated upon exposure to inflammatory stimuli and that a genetic knockout of NEU3 abrogates the sialidase activity of inflammatory microglial secretions. Moreover, we demonstrate that Neu3 is associated with a subpopulation of extracellular vesicles, possibly exosomes, that are secreted by microglia upon inflammatory insult. Finally, we demonstrate that Neu3 is necessary and sufficient to both desialylate neurons and decrease neuronal network connectivity. These results implicate Neu3 in remodeling of the glycocalyx leading to aberrant network-level activity of neurons, with implications in neuroinflammatory diseases such as Parkinson's disease and Alzheimer's disease.
Collapse
Affiliation(s)
- Corleone
S. Delaveris
- Department
of Chemistry and Sarafan ChEM-H, Stanford
University, Stanford, California 94305, United States
| | - Catherine L. Wang
- Department
of Chemistry and Sarafan ChEM-H, Stanford
University, Stanford, California 94305, United States
| | - Nicholas M. Riley
- Department
of Chemistry and Sarafan ChEM-H, Stanford
University, Stanford, California 94305, United States
| | - Sherry Li
- Department
of Chemistry and Sarafan ChEM-H, Stanford
University, Stanford, California 94305, United States
| | - Rishikesh U. Kulkarni
- Department
of Chemistry and Sarafan ChEM-H, Stanford
University, Stanford, California 94305, United States
| | - Carolyn R. Bertozzi
- Department
of Chemistry and Sarafan ChEM-H, Stanford
University, Stanford, California 94305, United States
- Howard
Hughes Medical Institute, Stanford, California 94305, United States
| |
Collapse
|
7
|
Bocharova O, Makarava N, Pandit NP, Molesworth K, Baskakov IV. Multiple steps of prion strain adaptation to a new host. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.24.563743. [PMID: 37961127 PMCID: PMC10634783 DOI: 10.1101/2023.10.24.563743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The transmission of prions across species is a critical aspect of their dissemination among mammalian hosts, including humans. This process often necessitates strain adaptation. In this study, we sought to investigate the mechanisms underlying prion adaptation while mitigating biases associated with the history of cross-species transmission of natural prion strains. To achieve this, we utilized the synthetic hamster prion strain S05. Propagation of S05 using mouse PrPC in Protein Misfolding Cyclic Amplification did not immediately overcome the species barrier. This finding underscores the involvement of factors beyond disparities in primary protein structures. Subsequently, we performed five serial passages to stabilize the incubation time to disease in mice. The levels of PrPSc increased with each passage, reaching a maximum at the third passage, and declining thereafter. This suggests that only the initial stage of adaptation is primarily driven by an acceleration in PrPSc replication. During the protracted adaptation to a new host, we observed significant alterations in the glycoform ratio and sialylation status of PrPSc N-glycans. These changes support the notion that qualitative modifications in PrPSc contribute to a more rapid disease progression. Furthermore, consistent with the decline in sialylation, a cue for "eat me" signaling, the newly adapted strain exhibited preferential colocalization with microglia. In contrast to PrPSc dynamics, the intensity of microglia activation continued to increase after the third passage in the new host. In summary, our study elucidates that the adaptation of a prion strain to a new host is a multi-step process driven by several factors.
Collapse
Affiliation(s)
- Olga Bocharova
- Center for Biomedical Engineering and Technology, Baltimore, Maryland, USA
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Natallia Makarava
- Center for Biomedical Engineering and Technology, Baltimore, Maryland, USA
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Narayan P. Pandit
- Center for Biomedical Engineering and Technology, Baltimore, Maryland, USA
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Kara Molesworth
- Center for Biomedical Engineering and Technology, Baltimore, Maryland, USA
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Ilia V. Baskakov
- Center for Biomedical Engineering and Technology, Baltimore, Maryland, USA
- Department of Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| |
Collapse
|
8
|
Deivasigamani S, Miteva MT, Natale S, Gutierrez-Barragan D, Basilico B, Di Angelantonio S, Weinhard L, Molotkov D, Deb S, Pape C, Bolasco G, Galbusera A, Asari H, Gozzi A, Ragozzino D, Gross CT. Microglia complement signaling promotes neuronal elimination and normal brain functional connectivity. Cereb Cortex 2023; 33:10750-10760. [PMID: 37718159 PMCID: PMC10629900 DOI: 10.1093/cercor/bhad313] [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: 12/05/2022] [Revised: 08/10/2023] [Accepted: 08/11/2023] [Indexed: 09/19/2023] Open
Abstract
Complement signaling is thought to serve as an opsonization signal to promote the phagocytosis of synapses by microglia. However, while its role in synaptic remodeling has been demonstrated in the retino-thalamic system, it remains unclear whether complement signaling mediates synaptic pruning in the brain more generally. Here we found that mice lacking the Complement receptor 3, the major microglia complement receptor, failed to show a deficit in either synaptic pruning or axon elimination in the developing mouse cortex. Instead, mice lacking Complement receptor 3 exhibited a deficit in the perinatal elimination of neurons in the cortex, a deficit that is associated with increased cortical thickness and enhanced functional connectivity in these regions in adulthood. These data demonstrate a role for complement in promoting neuronal elimination in the developing cortex.
Collapse
Affiliation(s)
- Senthilkumar Deivasigamani
- Epigenetics & Neurobiology Unit, EMBL Rome, European Molecular Biology Laboratory, Via Ramarini 32, 00015 Monterotondo, Italy
| | - Mariya T Miteva
- Epigenetics & Neurobiology Unit, EMBL Rome, European Molecular Biology Laboratory, Via Ramarini 32, 00015 Monterotondo, Italy
- Neuroscience Masters Programme, Sapienza University, Piazza Aldo Moro 1, 00185 Roma, Italy
| | - Silvia Natale
- Epigenetics & Neurobiology Unit, EMBL Rome, European Molecular Biology Laboratory, Via Ramarini 32, 00015 Monterotondo, Italy
- Division of Pharmacology, Department of Neuroscience, Reproductive and Odontostomatologic Sciences, School of Medicine, University of Naples Federico II, Via Pansini 5, 80131 Naples, Italy
| | - Daniel Gutierrez-Barragan
- Functional Neuroimaging Laboratory, Istituto Italiano di Tecnologia, Center for Neuroscience and Cognitive Systems @ UNITN, 38068 Rovereto, Italy
| | - Bernadette Basilico
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy
- Center for Life Nano- & Neuro-Science, Istituto Italiano di Tecnologia, 00161 Rome, Italy
| | - Silvia Di Angelantonio
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy
- Center for Life Nano- & Neuro-Science, Istituto Italiano di Tecnologia, 00161 Rome, Italy
| | - Laetitia Weinhard
- Epigenetics & Neurobiology Unit, EMBL Rome, European Molecular Biology Laboratory, Via Ramarini 32, 00015 Monterotondo, Italy
| | - Dmitry Molotkov
- Epigenetics & Neurobiology Unit, EMBL Rome, European Molecular Biology Laboratory, Via Ramarini 32, 00015 Monterotondo, Italy
| | - Sukrita Deb
- Epigenetics & Neurobiology Unit, EMBL Rome, European Molecular Biology Laboratory, Via Ramarini 32, 00015 Monterotondo, Italy
| | - Constantin Pape
- Cell Biology and Biophysics Unit, EMBL Heidelberg, Meyerhofstraße 1, 69117 Heidelberg, Germany
| | - Giulia Bolasco
- Epigenetics & Neurobiology Unit, EMBL Rome, European Molecular Biology Laboratory, Via Ramarini 32, 00015 Monterotondo, Italy
| | - Alberto Galbusera
- Functional Neuroimaging Laboratory, Istituto Italiano di Tecnologia, Center for Neuroscience and Cognitive Systems @ UNITN, 38068 Rovereto, Italy
| | - Hiroki Asari
- Epigenetics & Neurobiology Unit, EMBL Rome, European Molecular Biology Laboratory, Via Ramarini 32, 00015 Monterotondo, Italy
| | - Alessandro Gozzi
- Functional Neuroimaging Laboratory, Istituto Italiano di Tecnologia, Center for Neuroscience and Cognitive Systems @ UNITN, 38068 Rovereto, Italy
| | - Davide Ragozzino
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy
- Santa Lucia Foundation (IRCCS Fondazione Santa Lucia), Via Ardeatina, 00179 Rome, Italy
| | - Cornelius T Gross
- Epigenetics & Neurobiology Unit, EMBL Rome, European Molecular Biology Laboratory, Via Ramarini 32, 00015 Monterotondo, Italy
| |
Collapse
|
9
|
Delaveris CS, Wang CL, Riley NM, Li S, Kulkarni RU, Bertozzi CR. Microglia mediate contact-independent neuronal pruning via secreted Neuraminidase-3 associated with extracellular vesicles. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.21.554214. [PMID: 37662421 PMCID: PMC10473657 DOI: 10.1101/2023.08.21.554214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Neurons communicate with each other through electrochemical transmission at synapses. Microglia, the resident immune cells of the central nervous system, can prune these synapses through a variety of contact-dependent and -independent means. Microglial secretion of active sialidase enzymes upon exposure to inflammatory stimuli is one unexplored mechanism of pruning. Recent work from our lab showed that treatment of neurons with bacterial sialidases disrupts neuronal network connectivity. Here, we find that activated microglia secrete Neuraminidase-3 (Neu3) associated with fusogenic extracellular vesicles. Furthermore, we show Neu3 mediates contact-independent pruning of neurons and subsequent disruption of neuronal networks through neuronal glycocalyx remodeling. We observe that NEU3 is transcriptionally upregulated upon exposure to inflammatory stimuli, and that a genetic knock-out of NEU3 abrogates the sialidase activity of inflammatory microglial secretions. Moreover, we demonstrate that Neu3 is associated with a subpopulation of extracellular vesicles, possibly exosomes, that are secreted by microglia upon inflammatory insult. Finally, we demonstrate that Neu3 is both necessary and sufficient to both desialylate neurons and decrease neuronal network connectivity. These results implicate Neu3 in remodeling of the glycocalyx leading to aberrant network-level activity of neurons, with implications in neuroinflammatory diseases such as Parkinson's disease and Alzheimer's disease.
Collapse
Affiliation(s)
- Corleone S. Delaveris
- Stanford University, Department of Chemistry and Sarafan ChEM-H, Stanford, CA 94305, USA
| | - Catherine L. Wang
- Stanford University, Department of Chemistry and Sarafan ChEM-H, Stanford, CA 94305, USA
| | - Nicholas M. Riley
- Stanford University, Department of Chemistry and Sarafan ChEM-H, Stanford, CA 94305, USA
| | - Sherry Li
- Stanford University, Department of Chemistry and Sarafan ChEM-H, Stanford, CA 94305, USA
| | - Rishikesh U. Kulkarni
- Stanford University, Department of Chemistry and Sarafan ChEM-H, Stanford, CA 94305, USA
| | - Carolyn R. Bertozzi
- Stanford University, Department of Chemistry and Sarafan ChEM-H, Stanford, CA 94305, USA
- Howard Hughes Medical Institute, Stanford, CA 94305 USA
| |
Collapse
|
10
|
Cheng J, Wang W, Xia Y, Li Y, Jia J, Xiao G. Regulators of phagocytosis as pharmacologic targets for stroke treatment. Front Pharmacol 2023; 14:1122527. [PMID: 37601043 PMCID: PMC10433754 DOI: 10.3389/fphar.2023.1122527] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 07/20/2023] [Indexed: 08/22/2023] Open
Abstract
Stroke, including ischemic and hemorrhagic stroke, causes massive cell death in the brain, which is followed by secondary inflammatory injury initiated by disease-associated molecular patterns released from dead cells. Phagocytosis, a cellular process of engulfment and digestion of dead cells, promotes the resolution of inflammation and repair following stroke. However, professional or non-professional phagocytes also phagocytose stressed but viable cells in the brain or excessively phagocytose myelin sheaths or prune synapses, consequently exacerbating brain injury and impairing repair following stroke. Phagocytosis includes the smell, eating and digestion phases. Notably, efficient phagocytosis critically depends on phagocyte capacity to take up dead cells continually due to the limited number of phagocytes vs. dead cells after injury. Moreover, phenotypic polarization of phagocytes occurring after phagocytosis is also essential to the proresolving and prorepair properties of phagocytosis. Much has been learned about the molecular signals and regulatory mechanisms governing the sense and recognition of dead cells by phagocytes during the smell and eating phase following stroke. However, some key areas remain extremely understudied, including the mechanisms involved in digestion regulation, continual phagocytosis and phagocytosis-induced phenotypic switching following stroke. Here, we summarize new discoveries related to the molecular mechanisms and multifaceted effects of phagocytosis on brain injury and repair following stroke and highlight the knowledge gaps in poststroke phagocytosis. We suggest that advancing the understanding of poststroke phagocytosis will help identify more biological targets for stroke treatment.
Collapse
Affiliation(s)
- Jian Cheng
- Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, China
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Institute of Neuroscience, Soochow University, Suzhou, China
| | - Wei Wang
- Department of Pharmacy, The First Affiliated Hospital of Soochow University, Suzhou, China
| | - Yiqing Xia
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Institute of Neuroscience, Soochow University, Suzhou, China
| | - Yi Li
- Academy of Pharmacy, Xi’an Jiaotong-Liverpool University, Suzhou, China
| | - Jia Jia
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, College of Pharmaceutical Sciences, Soochow University, Suzhou, China
| | - Guodong Xiao
- Suzhou Clinical Research Center of Neurological Disease, Department of Neurology, The Second Affiliated Hospital of Soochow University, Suzhou, China
| |
Collapse
|
11
|
Liu LZ, Fan SJ, Gao JX, Li WB, Xian XH. Ceftriaxone ameliorates hippocampal synapse loss by inhibiting microglial/macrophages activation in glial glutamate transporter-1 dependent manner in the APP/PS1 mouse model of Alzheimer's disease. Brain Res Bull 2023:110683. [PMID: 37301482 DOI: 10.1016/j.brainresbull.2023.110683] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 05/29/2023] [Accepted: 06/06/2023] [Indexed: 06/12/2023]
Abstract
Synapse loss is a major contributor to cognitive dysfunction in Alzheimer's disease (AD). Impairments in the expression and/or glutamate uptake activity of glia glutamate transporter-1 (GLT-1) contribute to synapse loss in AD. Hence, targeting the restoration of GLT-1 activity may have potential for alleviating synapse loss in AD. Ceftriaxone (Cef) can upregulate the expression and glutamate uptake activity of GLT-1 in many disease models, including those for AD. The present study investigated the effects of Cef on synapse loss and the role of GLT-1 using APP/PS1 transgenic and GLT-1 knockdown APP/PS1 AD mice. Furthermore, the involvement of microglia in the process was investigated due to its important role in synapse loss in AD. We found that Cef treatment significantly ameliorated synapse loss and dendritic degeneration in APP/PS1 AD mice, evidenced by an increased dendritic spine density, decreased dendritic beading density, and upregulated levels of postsynaptic density protein 95 (PSD95) and synaptophysin. The effects of Cef were suppressed by GLT-1 knockdown in GLT-1+/-/APP/PS1 AD mice. Simultaneously, Cef treatment inhibited ionized calcium binding adapter molecule 1 (Iba1) expression, decreased the proportion of CD11b+CD45hi cells, declined interleukin-6 (IL-6) content, and reduced the co-expression of Iba1 with PSD95 or synaptophysin in APP/PS1 AD mice. In conclusion, Cef treatment ameliorated synapse loss and dendritic degeneration in APP/PS1 AD mice in a GLT-1-dependent manner, and the inhibitory effect of Cef on the activation of microglia/macrophages and their phagocytosis for synaptic elements contributed to the mechanism.
Collapse
Affiliation(s)
- Li-Zhe Liu
- Department of Pathophysiology, Neuroscience Research Center, Hebei Medical University, P.R. China; Department of Pathophysiology, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang, 050017, P. R. China.
| | - Shu-Juan Fan
- Department of Pathophysiology, Neuroscience Research Center, Hebei Medical University, P.R. China; Department of Pathophysiology, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang, 050017, P. R. China.
| | - Jun-Xia Gao
- Department of Pathophysiology, Neuroscience Research Center, Hebei Medical University, P.R. China; Department of Pathophysiology, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang, 050017, P. R. China.
| | - Wen-Bin Li
- Department of Pathophysiology, Neuroscience Research Center, Hebei Medical University, P.R. China; Department of Pathophysiology, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang, 050017, P. R. China.
| | - Xiao-Hui Xian
- Department of Pathophysiology, Neuroscience Research Center, Hebei Medical University, P.R. China; Department of Pathophysiology, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang, 050017, P. R. China.
| |
Collapse
|
12
|
Makarava N, Baskakov IV. Role of sialylation of N-linked glycans in prion pathogenesis. Cell Tissue Res 2023; 392:201-214. [PMID: 35088180 PMCID: PMC9329487 DOI: 10.1007/s00441-022-03584-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 01/12/2022] [Indexed: 01/10/2023]
Abstract
Mammalian prion or PrPSc is a proteinaceous infectious agent that consists of a misfolded, self-replicating state of the prion protein or PrPC. PrPC and PrPSc are posttranslationally modified with N-linked glycans, which are sialylated at the terminal positions. More than 30 years have passed since the first characterization of the composition and structural diversity of N-linked glycans associated with the prion protein, yet the role of carbohydrate groups that constitute N-glycans and, in particular, their terminal sialic acid residues in prion disease pathogenesis remains poorly understood. A number of recent studies shed a light on the role of sialylation in the biology of prion diseases. This review article discusses several mechanisms by which terminal sialylation dictates the spread of PrPSc across brain regions and the outcomes of prion infection in an organism. In particular, relationships between the sialylation status of PrPSc and important strain-specific features including lymphotropism, neurotropism, and neuroinflammation are discussed. Moreover, emerging evidence pointing out the roles of sialic acid residues in prion replication, cross-species transmission, strain competition, and strain adaptation are reviewed. A hypothesis according to which selective, strain-specified recruitment of PrPC sialoglycoforms dictates unique strain-specific disease phenotypes is examined. Finally, the current article proposes that prion strains evolve as a result of a delicate balance between recruiting highly sialylated glycoforms to avoid an "eat-me" response by glia and limiting heavily sialylated glycoforms for enabling rapid prion replication.
Collapse
Affiliation(s)
- Natallia Makarava
- Center for Biomedical Engineering and Technology and Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Ilia V Baskakov
- Center for Biomedical Engineering and Technology and Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
| |
Collapse
|
13
|
VanderZwaag J, Halvorson T, Dolhan K, Šimončičová E, Ben-Azu B, Tremblay MÈ. The Missing Piece? A Case for Microglia's Prominent Role in the Therapeutic Action of Anesthetics, Ketamine, and Psychedelics. Neurochem Res 2023; 48:1129-1166. [PMID: 36327017 DOI: 10.1007/s11064-022-03772-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 08/25/2022] [Accepted: 09/27/2022] [Indexed: 11/06/2022]
Abstract
There is much excitement surrounding recent research of promising, mechanistically novel psychotherapeutics - psychedelic, anesthetic, and dissociative agents - as they have demonstrated surprising efficacy in treating central nervous system (CNS) disorders, such as mood disorders and addiction. However, the mechanisms by which these drugs provide such profound psychological benefits are still to be fully elucidated. Microglia, the CNS's resident innate immune cells, are emerging as a cellular target for psychiatric disorders because of their critical role in regulating neuroplasticity and the inflammatory environment of the brain. The following paper is a review of recent literature surrounding these neuropharmacological therapies and their demonstrated or hypothesized interactions with microglia. Through investigating the mechanism of action of psychedelics, such as psilocybin and lysergic acid diethylamide, ketamine, and propofol, we demonstrate a largely under-investigated role for microglia in much of the emerging research surrounding these pharmacological agents. Among others, we detail sigma-1 receptors, serotonergic and γ-aminobutyric acid signalling, and tryptophan metabolism as pathways through which these agents modulate microglial phagocytic activity and inflammatory mediator release, inducing their therapeutic effects. The current review includes a discussion on future directions in the field of microglial pharmacology and covers bidirectional implications of microglia and these novel pharmacological agents in aging and age-related disease, glial cell heterogeneity, and state-of-the-art methodologies in microglial research.
Collapse
Affiliation(s)
- Jared VanderZwaag
- Neuroscience Graduate Program, University of Victoria, Victoria, BC, Canada
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Torin Halvorson
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
- BC Children's Hospital Research Institute, Vancouver, BC, Canada
| | - Kira Dolhan
- Department of Psychology, University of Victoria, Vancouver, BC, Canada
- Department of Biology, University of Victoria, Vancouver, BC, Canada
| | - Eva Šimončičová
- Neuroscience Graduate Program, University of Victoria, Victoria, BC, Canada
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Benneth Ben-Azu
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Department of Pharmacology, Faculty of Basic Medical Sciences, College of Health Sciences, Delta State University, Abraka, Delta State, Nigeria
| | - Marie-Ève Tremblay
- Neuroscience Graduate Program, University of Victoria, Victoria, BC, Canada.
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada.
- Département de médecine moléculaire, Université Laval, Québec City, QC, Canada.
- Axe Neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Québec City, QC, Canada.
- Neurology and Neurosurgery Department, McGill University, Montreal, QC, Canada.
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada.
- Centre for Advanced Materials and Related Technology (CAMTEC), University of Victoria, Victoria, BC, Canada.
- Institute for Aging and Lifelong Health, University of Victoria, Victoria, BC, Canada.
| |
Collapse
|
14
|
Stennett A, Friston K, Harris CL, Wollman AJM, Bronowska AK, Madden KS. The case for complement component 5 as a target in neurodegenerative disease. Expert Opin Ther Targets 2023; 27:97-109. [PMID: 36786123 DOI: 10.1080/14728222.2023.2177532] [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: 02/15/2023]
Abstract
INTRODUCTION Complement-based drug discovery is undergoing a renaissance, empowered by new advances in structural biology, complement biology and drug development. Certain components of the complement pathway, particularly C1q and C3, have been extensively studied in the context of neurodegenerative disease, and established as key therapeutic targets. C5 also has huge therapeutic potential in this arena, with its druggability clearly demonstrated by the success of C5-inhibitor eculizumab. AREAS COVERED We will discuss the evidence supporting C5 as a target in neurodegenerative disease, along with the current progress in developing different classes of C5 inhibitors and the gaps in knowledge that will help progress in the field. EXPERT OPINION Validation of C5 as a therapeutic target for neurodegenerative disease would represent a major step forward for complement therapeutics research and has the potential to furnish disease-modifying drugs for millions of patients suffering worldwide. Key hurdles that need to be overcome for this to be achieved are understanding how C5a and C5b should be targeted to bring therapeutic benefit and demonstrating the ability to target C5 without creating vulnerability to infection in patients. This requires greater biological elucidation of its precise role in disease pathogenesis, supported by better chemical/biological tools.
Collapse
Affiliation(s)
- Amelia Stennett
- School of Natural and Environmental Sciences, Newcastle University, NE1 7RU, Newcastle-Upon-Tyne, UK
| | - Kallie Friston
- School of Natural and Environmental Sciences, Newcastle University, NE1 7RU, Newcastle-Upon-Tyne, UK
| | - Claire L Harris
- Faculty of Medical Sciences, Newcastle University, NE2 4HH, Newcastle-Upon-Tyne, UK
| | - Adam J M Wollman
- Faculty of Medical Sciences, Newcastle University, NE2 4HH, Newcastle-Upon-Tyne, UK
| | - Agnieszka K Bronowska
- School of Natural and Environmental Sciences, Newcastle University, NE1 7RU, Newcastle-Upon-Tyne, UK
| | - Katrina S Madden
- School of Natural and Environmental Sciences, Newcastle University, NE1 7RU, Newcastle-Upon-Tyne, UK.,Faculty of Medical Sciences, Newcastle University, NE2 4HH, Newcastle-Upon-Tyne, UK
| |
Collapse
|
15
|
Chen W, Zhang Y, Zhai X, Xie L, Guo Y, Chen C, Li Y, Wang F, Zhu Z, Zheng L, Wan J, Li P. Microglial phagocytosis and regulatory mechanisms after stroke. J Cereb Blood Flow Metab 2022; 42:1579-1596. [PMID: 35491825 PMCID: PMC9441720 DOI: 10.1177/0271678x221098841] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Stroke, including ischemic stroke and hemorrhagic stroke can cause massive neuronal death and disruption of brain structure, which is followed by secondary inflammatory injury initiated by pro-inflammatory molecules and cellular debris. Phagocytic clearance of cellular debris by microglia, the brain's scavenger cells, is pivotal for neuroinflammation resolution and neurorestoration. However, microglia can also exacerbate neuronal loss by phagocytosing stressed-but-viable neurons in the penumbra, thereby expanding the injury area and hindering neurofunctional recovery. Microglia constantly patrol the central nervous system using their processes to scour the cellular environment and start or cease the phagocytosis progress depending on the "eat me" or "don't eat me'' signals on cellular surface. An optimal immune response requires a delicate balance between different phenotypic states to regulate neuro-inflammation and facilitate reconstruction after stroke. Here, we examine the literature and discuss the molecular mechanisms and cellular pathways regulating microglial phagocytosis, their resulting effects in brain injury and neural regeneration, as well as the potential therapeutic targets that might modulate microglial phagocytic activity to improve neurological function after stroke.
Collapse
Affiliation(s)
- Weijie Chen
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yueman Zhang
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaozhu Zhai
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lv Xie
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yunlu Guo
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chen Chen
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yan Li
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Fajun Wang
- Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Ziyu Zhu
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Li Zheng
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jieqing Wan
- Department of Neurosurgery, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Peiying Li
- Department of Anesthesiology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| |
Collapse
|
16
|
Yu F, Wang Y, Stetler AR, Leak RK, Hu X, Chen J. Phagocytic microglia and macrophages in brain injury and repair. CNS Neurosci Ther 2022; 28:1279-1293. [PMID: 35751629 PMCID: PMC9344092 DOI: 10.1111/cns.13899] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 05/31/2022] [Accepted: 06/04/2022] [Indexed: 12/21/2022] Open
Abstract
AIMS Phagocytosis is the cellular digestion of extracellular particles, such as pathogens and dying cells, and is a key element in the evolution of central nervous system (CNS) disorders. Microglia and macrophages are the professional phagocytes of the CNS. By clearing toxic cellular debris and reshaping the extracellular matrix, microglia/macrophages help pilot the brain repair and functional recovery process. However, CNS resident and invading immune cells can also magnify tissue damage by igniting runaway inflammation and phagocytosing stressed-but viable-neurons. DISCUSSION Microglia/macrophages help mediate intercellular communication and react quickly to the "find-me" signals expressed by dead/dying neurons. The activated microglia/macrophages then migrate to the injury site to initiate the phagocytic process upon encountering "eat-me" signals on the surfaces of endangered cells. Thus, healthy cells attempt to avoid inappropriate engulfment by expressing "do not-eat-me" signals. Microglia/macrophages also have the capacity to phagocytose immune cells that invade the injured brain (e.g., neutrophils) and to regulate their pro-inflammatory properties. During brain recovery, microglia/macrophages engulf myelin debris, initiate synaptogenesis and neurogenesis, and sculpt a favorable extracellular matrix to support network rewiring, among other favorable roles. Here, we review the multilayered nature of phagocytotic microglia/macrophages, including the molecular and cellular mechanisms that govern microglia/macrophage-induced phagocytosis in acute brain injury, and discuss strategies that tap into the therapeutic potential of this engulfment process. CONCLUSION Identification of biological targets that can temper neuroinflammation after brain injury without hindering the essential phagocytic functions of microglia/macrophages will expedite better medical management of the stroke recovery stage.
Collapse
Affiliation(s)
- Fang Yu
- Geriatric Research, Education and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, Pennsylvania, USA.,Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Yangfan Wang
- Geriatric Research, Education and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, Pennsylvania, USA.,Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Anne R Stetler
- Geriatric Research, Education and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, Pennsylvania, USA.,Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Rehana K Leak
- Graduate School of Pharmaceutical Sciences, School of Pharmacy, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Xiaoming Hu
- Geriatric Research, Education and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, Pennsylvania, USA.,Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Jun Chen
- Geriatric Research, Education and Clinical Center, Veterans Affairs Pittsburgh Health Care System, Pittsburgh, Pennsylvania, USA.,Pittsburgh Institute of Brain Disorders & Recovery and Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| |
Collapse
|
17
|
Gonçalves de Andrade E, González Ibáñez F, Tremblay MÈ. Microglia as a Hub for Suicide Neuropathology: Future Investigation and Prevention Targets. Front Cell Neurosci 2022; 16:839396. [PMID: 35663424 PMCID: PMC9158339 DOI: 10.3389/fncel.2022.839396] [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: 12/19/2021] [Accepted: 02/22/2022] [Indexed: 12/27/2022] Open
Abstract
Suicide is a complex public health challenge associated worldwide with one death every 40 s. Research advances in the neuropathology of suicidal behaviors (SB) have defined discrete brain changes which may hold the key to suicide prevention. Physiological differences in microglia, the resident immune cells of the brain, are present in post-mortem tissue samples of individuals who died by suicide. Furthermore, microglia are mechanistically implicated in the outcomes of important risk factors for SB, including early-life adversity, stressful life events, and psychiatric disorders. SB risk factors result in inflammatory and oxidative stress activities which could converge to microglial synaptic remodeling affecting susceptibility or resistance to SB. To push further this perspective, in this Review we summarize current areas of opportunity that could untangle the functional participation of microglia in the context of suicide. Our discussion centers around microglial state diversity in respect to morphology, gene and protein expression, as well as function, depending on various factors, namely brain region, age, and sex.
Collapse
Affiliation(s)
- Elisa Gonçalves de Andrade
- Neuroscience Graduate Program, Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Fernando González Ibáñez
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Axe Neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Québec City, QC, Canada
| | - Marie-Ève Tremblay
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Axe Neurosciences, Centre de Recherche du CHU de Québec, Université Laval, Québec City, QC, Canada
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
- Department of Molecular Medicine, Université Laval, Québec City, QC, Canada
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
- Centre for Advanced Materials and Related Technology (CAMTEC), University of Victoria, Victoria, BC, Canada
- *Correspondence: Marie-Ève Tremblay,
| |
Collapse
|
18
|
Shahraz A, Lin Y, Mbroh J, Winkler J, Liao H, Lackmann M, Bungartz A, Zipfel PF, Skerka C, Neumann H. Low molecular weight polysialic acid binds to properdin and reduces the activity of the alternative complement pathway. Sci Rep 2022; 12:5818. [PMID: 35388026 PMCID: PMC8987038 DOI: 10.1038/s41598-022-09407-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 03/21/2022] [Indexed: 11/09/2022] Open
Abstract
Sialic acids as the terminal caps of the cellular glycocalyx play an essential role in self-recognition and were shown to modulate complement processes via interaction between α2,3-linked sialic acids and complement factor H. Previously, it was suggested that low molecular weight α2,8-linked polysialic acid (polySia avDP20) interferes with complement activation, but the exact molecular mechanism is still unclear. Here, we show that soluble polySia avDP20 (molecular weight of ~ 6 kDa) reduced the binding of serum-derived alternative pathway complement activator properdin to the cell surface of lesioned Hepa-1c1c7 and PC-12 neuroblastoma cells. Furthermore, polySia avDP20 added to human serum blocked the alternative complement pathway triggered by plate-bound lipopolysaccharides. Interestingly, no inhibitory effect was observed with monosialic acid or oligosialic acid with a chain length of DP3 and DP5. In addition, polySia avDP20 directly bound properdin, but not complement factor H. These data show that soluble polySia avDP20 binds properdin and reduces the alternative complement pathway activity. Results strengthen the previously described concept of self-recognition of sialylation as check-point control of complement activation in innate immunity.
Collapse
Affiliation(s)
- Anahita Shahraz
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Yuchen Lin
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Joshua Mbroh
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Jonas Winkler
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Huan Liao
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Marie Lackmann
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Annemarie Bungartz
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany
| | - Peter F Zipfel
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany.,Infection Biology, Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Christine Skerka
- Department of Infection Biology, Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany
| | - Harald Neumann
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Venusberg-Campus 1, 53127, Bonn, Germany.
| |
Collapse
|
19
|
García-Martínez M, Cortez LM, Otero A, Betancor M, Serrano-Pérez B, Bolea R, Badiola JJ, Garza MC. Distinctive Toll-like Receptors Gene Expression and Glial Response in Different Brain Regions of Natural Scrapie. Int J Mol Sci 2022; 23:ijms23073579. [PMID: 35408945 PMCID: PMC8998348 DOI: 10.3390/ijms23073579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 03/22/2022] [Accepted: 03/23/2022] [Indexed: 11/16/2022] Open
Abstract
Prion diseases are chronic and fatal neurodegenerative diseases characterized by the accumulation of disease-specific prion protein (PrPSc), spongiform changes, neuronal loss, and gliosis. Growing evidence shows that the neuroinflammatory response is a key component of prion diseases and contributes to neurodegeneration. Toll-like receptors (TLRs) have been proposed as important mediators of innate immune responses triggered in the central nervous system in other human neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis. However, little is known about the role of TLRs in prion diseases, and their involvement in the neuropathology of natural scrapie has not been studied. We assessed the gene expression of ovine TLRs in four anatomically distinct brain regions in natural scrapie-infected sheep and evaluated the possible correlations between gene expression and the pathological hallmarks of prion disease. We observed significant changes in TLR expression in scrapie-infected sheep that correlate with the degree of spongiosis, PrPSc deposition, and gliosis in each of the regions studied. Remarkably, TLR4 was the only gene upregulated in all regions, regardless of the severity of neuropathology. In the hippocampus, we observed milder neuropathology associated with a distinct TLR gene expression profile and the presence of a peculiar microglial morphology, called rod microglia, described here for the first time in the brain of scrapie-infected sheep. The concurrence of these features suggests partial neuroprotection of the hippocampus. Finally, a comparison of the findings in naturallyinfected sheep versus an ovinized mouse model (tg338 mice) revealed distinct patterns of TLRgene expression.
Collapse
Affiliation(s)
- Mirta García-Martínez
- Centro de Encefalopatías y Enfermedades Transmisibles Emergentes, IA2, IIS Aragón, Universidad de Zaragoza, 50013 Zaragoza, Spain; (M.G.-M.); (M.B.); (R.B.); (J.J.B.)
| | - Leonardo M. Cortez
- Department of Medicine and Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, AB T6G 2G3, Canada
- Correspondence: (L.M.C.); (A.O.)
| | - Alicia Otero
- Centro de Encefalopatías y Enfermedades Transmisibles Emergentes, IA2, IIS Aragón, Universidad de Zaragoza, 50013 Zaragoza, Spain; (M.G.-M.); (M.B.); (R.B.); (J.J.B.)
- Correspondence: (L.M.C.); (A.O.)
| | - Marina Betancor
- Centro de Encefalopatías y Enfermedades Transmisibles Emergentes, IA2, IIS Aragón, Universidad de Zaragoza, 50013 Zaragoza, Spain; (M.G.-M.); (M.B.); (R.B.); (J.J.B.)
| | - Beatriz Serrano-Pérez
- Agrotecnio-CERCA Center, Department of Animal Science, University of Lleida, 25198 Lleida, Spain;
| | - Rosa Bolea
- Centro de Encefalopatías y Enfermedades Transmisibles Emergentes, IA2, IIS Aragón, Universidad de Zaragoza, 50013 Zaragoza, Spain; (M.G.-M.); (M.B.); (R.B.); (J.J.B.)
| | - Juan J. Badiola
- Centro de Encefalopatías y Enfermedades Transmisibles Emergentes, IA2, IIS Aragón, Universidad de Zaragoza, 50013 Zaragoza, Spain; (M.G.-M.); (M.B.); (R.B.); (J.J.B.)
| | - María Carmen Garza
- Departamento de Anatomía e Histología Humanas, IIS Aragón, Universidad de Zaragoza, 50009 Zaragoza, Spain;
| |
Collapse
|
20
|
Konishi H, Koizumi S, Kiyama H. Phagocytic astrocytes: Emerging from the shadows of microglia. Glia 2022; 70:1009-1026. [PMID: 35142399 PMCID: PMC9305589 DOI: 10.1002/glia.24145] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 12/18/2021] [Accepted: 01/07/2022] [Indexed: 12/12/2022]
Abstract
Elimination of dead or live cells take place in both a healthy and diseased central nervous system (CNS). Dying or dead cells are quickly cleared by phagocytosis for the maintenance of a healthy CNS or for recovery after injury. Live cells or parts thereof, such as the synapses and myelin, are appropriately eliminated by phagocytosis to maintain or refine neural networks during development and adulthood. Microglia, the specific population of resident macrophages in the CNS, are classically considered as primary phagocytes; however, astrocytes have also been highlighted as phagocytes in the last decade. Phagocytic targets and receptors are reported to be mostly common between astrocytes and microglia, which raises the question of how astrocytic phagocytosis differs from microglial phagocytosis, and how these two phagocytic systems cooperate. In this review, we address the consequences of astrocytic phagocytosis, particularly focusing on these elusive points.
Collapse
Affiliation(s)
- Hiroyuki Konishi
- Department of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Schuichi Koizumi
- Department of Neuropharmacology, University of Yamanashi, Yamanashi, Japan.,GLIA Center, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Hiroshi Kiyama
- Department of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, Nagoya, Japan
| |
Collapse
|
21
|
Jia J, Yang L, Chen Y, Zheng L, Chen Y, Xu Y, Zhang M. The Role of Microglial Phagocytosis in Ischemic Stroke. Front Immunol 2022; 12:790201. [PMID: 35082781 PMCID: PMC8784388 DOI: 10.3389/fimmu.2021.790201] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 12/14/2021] [Indexed: 12/14/2022] Open
Abstract
Microglia are the resident immune cells of the central nervous system that exert diverse roles in the pathogenesis of ischemic stroke. During the past decades, microglial polarization and chemotactic properties have been well-studied, whereas less attention has been paid to phagocytic phenotypes of microglia in stroke. Generally, whether phagocytosis mediated by microglia plays a beneficial or detrimental role in stroke remains controversial, which calls for further investigations. Most researchers are in favor of the former proposal currently since efficient clearance of tissue debris promotes tissue reconstruction and neuronal network reorganization in part. Other scholars propose that excessively activated microglia engulf live or stressed neuronal cells, which results in neurological deficits and brain atrophy. Upon ischemia challenge, the microglia infiltrate injured brain tissue and engulf live/dead neurons, myelin debris, apoptotic cell debris, endothelial cells, and leukocytes. Cell phagocytosis is provoked by the exposure of "eat-me" signals or the loss of "don't eat-me" signals. We supposed that microglial phagocytosis could be initiated by the specific "eat-me" signal and its corresponding receptor on the specific cell type under pathological circumstances. In this review, we will summarize phagocytic characterizations of microglia after stroke and the potential receptors responsible for this programmed biological progress. Understanding these questions precisely may help to develop appropriate phagocytic regulatory molecules, which are promoting self-limiting inflammation without damaging functional cells.
Collapse
Affiliation(s)
- Junqiu Jia
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing, China
| | - Lixuan Yang
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing, China
| | - Yan Chen
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing, China
| | - Lili Zheng
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing, China
| | - Yanting Chen
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing, China
| | - Yun Xu
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing, China.,Jiangsu Key Laboratory for Molecular Medicine, Medical School of Nanjing University, Nanjing, China.,Jiangsu Province Stroke Center for Diagnosis and Therapy, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China.,Nanjing Neuropsychiatry Clinic Medical Center, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Meijuan Zhang
- Department of Neurology, Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing, China.,Jiangsu Key Laboratory for Molecular Medicine, Medical School of Nanjing University, Nanjing, China.,Jiangsu Province Stroke Center for Diagnosis and Therapy, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China.,Nanjing Neuropsychiatry Clinic Medical Center, Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| |
Collapse
|
22
|
Williams SE, Noel M, Lehoux S, Cetinbas M, Xavier RJ, Sadreyev RI, Scolnick EM, Smoller JW, Cummings RD, Mealer RG. Mammalian brain glycoproteins exhibit diminished glycan complexity compared to other tissues. Nat Commun 2022; 13:275. [PMID: 35022400 PMCID: PMC8755730 DOI: 10.1038/s41467-021-27781-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 12/08/2021] [Indexed: 01/14/2023] Open
Abstract
Glycosylation is essential to brain development and function, but prior studies have often been limited to a single analytical technique and excluded region- and sex-specific analyses. Here, using several methodologies, we analyze Asn-linked and Ser/Thr/Tyr-linked protein glycosylation between brain regions and sexes in mice. Brain N-glycans are less complex in sequence and variety compared to other tissues, consisting predominantly of high-mannose and fucosylated/bisected structures. Most brain O-glycans are unbranched, sialylated O-GalNAc and O-mannose structures. A consistent pattern is observed between regions, and sex differences are minimal compared to those in plasma. Brain glycans correlate with RNA expression of their synthetic enzymes, and analysis of glycosylation genes in humans show a global downregulation in the brain compared to other tissues. We hypothesize that this restricted repertoire of protein glycans arises from their tight regulation in the brain. These results provide a roadmap for future studies of glycosylation in neurodevelopment and disease.
Collapse
Affiliation(s)
- Sarah E Williams
- Psychiatric and Neurodevelopmental Genetics Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Maxence Noel
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Sylvain Lehoux
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Murat Cetinbas
- Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Ramnik J Xavier
- Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Center for Computational and Integrative Biology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Ruslan I Sadreyev
- Department of Molecular Biology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Edward M Scolnick
- Psychiatric and Neurodevelopmental Genetics Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- The Stanley Center for Psychiatric Research at Broad Institute of Harvard/MIT, Cambridge, MA, USA
| | - Jordan W Smoller
- Psychiatric and Neurodevelopmental Genetics Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- The Stanley Center for Psychiatric Research at Broad Institute of Harvard/MIT, Cambridge, MA, USA
- Center for Precision Psychiatry, Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Richard D Cummings
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Robert G Mealer
- Psychiatric and Neurodevelopmental Genetics Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
- Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
- The Stanley Center for Psychiatric Research at Broad Institute of Harvard/MIT, Cambridge, MA, USA.
- Center for Precision Psychiatry, Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
| |
Collapse
|
23
|
Lu BW, Chao GJ, Wu GP, Xie LK. In depth understanding of retinitis pigmentosa pathogenesis through optical coherence tomography angiography analysis: a narrative review. Int J Ophthalmol 2021; 14:1979-1985. [PMID: 34926217 DOI: 10.18240/ijo.2021.12.25] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 09/13/2021] [Indexed: 12/11/2022] Open
Abstract
Retinitis pigmentosa (RP) is the most recognized inherited retinal disorder involving progressive photoreceptors degeneration which eventually causes blindness. However, the pathogenesis of RP is still unclear, making it difficult to establish satisfying treatments. Evidence have been found to support the theory that vascular dysfunction is associated with the progression of RP. Optical coherence tomography angiography (OCTA) is a newly developed technology that enables visualization as well as quantitative assessment of retinal and choroidal vasculature non-invasively. Advances in OCTA have opened a window for in-depth understanding of RP pathogenesis. Here, we propose a hypothesis of RP pathogenesis based on the current OCTA findings in RP, which includes four stages and two important key factors, vascular dysfunction and microglia activation. Further, we discuss the future animal experiments needed and how advanced OCTA technology can help to further verity the hypothesis. The final goal is to explore potential treatment options with enhanced understanding of RP pathogenesis.
Collapse
Affiliation(s)
- Bing-Wen Lu
- Department of Ophthalmology, Ophthalmology Hospital of China Academy of Traditional Chinese Medicine, Beijing 100040, China
| | - Guo-Jun Chao
- Department of Ophthalmology, Ophthalmology Hospital of China Academy of Traditional Chinese Medicine, Beijing 100040, China
| | - Gai-Ping Wu
- Department of Ophthalmology, Ophthalmology Hospital of China Academy of Traditional Chinese Medicine, Beijing 100040, China
| | - Li-Ke Xie
- Department of Ophthalmology, Ophthalmology Hospital of China Academy of Traditional Chinese Medicine, Beijing 100040, China
| |
Collapse
|
24
|
Brown GC. Neuronal Loss after Stroke Due to Microglial Phagocytosis of Stressed Neurons. Int J Mol Sci 2021; 22:13442. [PMID: 34948237 PMCID: PMC8707068 DOI: 10.3390/ijms222413442] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/09/2021] [Accepted: 12/10/2021] [Indexed: 11/17/2022] Open
Abstract
After stroke, there is a rapid necrosis of all cells in the infarct, followed by a delayed loss of neurons both in brain areas surrounding the infarct, known as 'selective neuronal loss', and in brain areas remote from, but connected to, the infarct, known as 'secondary neurodegeneration'. Here we review evidence indicating that this delayed loss of neurons after stroke is mediated by the microglial phagocytosis of stressed neurons. After a stroke, neurons are stressed by ongoing ischemia, excitotoxicity and/or inflammation and are known to: (i) release "find-me" signals such as ATP, (ii) expose "eat-me" signals such as phosphatidylserine, and (iii) bind to opsonins, such as complement components C1q and C3b, inducing microglia to phagocytose such neurons. Blocking these factors on neurons, or their phagocytic receptors on microglia, can prevent delayed neuronal loss and behavioral deficits in rodent models of ischemic stroke. Phagocytic receptors on microglia may be attractive treatment targets to prevent delayed neuronal loss after stroke due to the microglial phagocytosis of stressed neurons.
Collapse
Affiliation(s)
- Guy C Brown
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, UK
| |
Collapse
|
25
|
Crapser JD, Arreola MA, Tsourmas KI, Green KN. Microglia as hackers of the matrix: sculpting synapses and the extracellular space. Cell Mol Immunol 2021; 18:2472-2488. [PMID: 34413489 PMCID: PMC8546068 DOI: 10.1038/s41423-021-00751-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 07/26/2021] [Indexed: 02/08/2023] Open
Abstract
Microglia shape the synaptic environment in health and disease, but synapses do not exist in a vacuum. Instead, pre- and postsynaptic terminals are surrounded by extracellular matrix (ECM), which together with glia comprise the four elements of the contemporary tetrapartite synapse model. While research in this area is still just beginning, accumulating evidence points toward a novel role for microglia in regulating the ECM during normal brain homeostasis, and such processes may, in turn, become dysfunctional in disease. As it relates to synapses, microglia are reported to modify the perisynaptic matrix, which is the diffuse matrix that surrounds dendritic and axonal terminals, as well as perineuronal nets (PNNs), specialized reticular formations of compact ECM that enwrap neuronal subsets and stabilize proximal synapses. The interconnected relationship between synapses and the ECM in which they are embedded suggests that alterations in one structure necessarily affect the dynamics of the other, and microglia may need to sculpt the matrix to modify the synapses within. Here, we provide an overview of the microglial regulation of synapses, perisynaptic matrix, and PNNs, propose candidate mechanisms by which these structures may be modified, and present the implications of such modifications in normal brain homeostasis and in disease.
Collapse
Affiliation(s)
- Joshua D. Crapser
- grid.266093.80000 0001 0668 7243Department of Neurobiology and Behavior, University of California, Irvine, CA USA
| | - Miguel A. Arreola
- grid.266093.80000 0001 0668 7243Department of Neurobiology and Behavior, University of California, Irvine, CA USA
| | - Kate I. Tsourmas
- grid.266093.80000 0001 0668 7243Department of Neurobiology and Behavior, University of California, Irvine, CA USA
| | - Kim N. Green
- grid.266093.80000 0001 0668 7243Department of Neurobiology and Behavior, University of California, Irvine, CA USA
| |
Collapse
|
26
|
Faust TE, Gunner G, Schafer DP. Mechanisms governing activity-dependent synaptic pruning in the developing mammalian CNS. Nat Rev Neurosci 2021; 22:657-673. [PMID: 34545240 PMCID: PMC8541743 DOI: 10.1038/s41583-021-00507-y] [Citation(s) in RCA: 144] [Impact Index Per Article: 48.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2021] [Indexed: 02/08/2023]
Abstract
Almost 60 years have passed since the initial discovery by Hubel and Wiesel that changes in neuronal activity can elicit developmental rewiring of the central nervous system (CNS). Over this period, we have gained a more comprehensive picture of how both spontaneous neural activity and sensory experience-induced changes in neuronal activity guide CNS circuit development. Here we review activity-dependent synaptic pruning in the mammalian CNS, which we define as the removal of a subset of synapses, while others are maintained, in response to changes in neural activity in the developing nervous system. We discuss the mounting evidence that immune and cell-death molecules are important mechanistic links by which changes in neural activity guide the pruning of specific synapses, emphasizing the role of glial cells in this process. Finally, we discuss how these developmental pruning programmes may go awry in neurodevelopmental disorders of the human CNS, focusing on autism spectrum disorder and schizophrenia. Together, our aim is to give an overview of how the field of activity-dependent pruning research has evolved, led to exciting new questions and guided the identification of new, therapeutically relevant mechanisms that result in aberrant circuit development in neurodevelopmental disorders.
Collapse
Affiliation(s)
- Travis E Faust
- Department of Neurobiology, Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester, MA, USA
| | - Georgia Gunner
- Department of Neurobiology, Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester, MA, USA
| | - Dorothy P Schafer
- Department of Neurobiology, Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester, MA, USA.
| |
Collapse
|
27
|
Hayes JM, O'Hara DM, Davey GP. Metabolic Labeling of Primary Neurons Using Carbohydrate Click Chemistry. Methods Mol Biol 2021; 2370:315-322. [PMID: 34611877 DOI: 10.1007/978-1-0716-1685-7_16] [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: 02/25/2023]
Abstract
Glycans play an important role in many neuronal processes, such as neurotransmitter release and reuptake, cell-cell communication and adhesion, modulation of ion channel activity, and immune function. Carbohydrate click chemistry is a powerful technique for studying glycan function and dynamics in vitro, in vivo, and ex vivo. Here, we use commercially available synthetic tetraacetylated azido sugars, copper and copper-free click chemistry to metabolically label and analyze primary rat cortical neurons. In addition, we use high resolution confocal and STED microscopy to image and analyze different forms of glycosylation in ultrahigh resolution. We observe different patterns of GlcNAz, GalNAz, and ManNAz distribution at different stages of neuronal development. We also observe highly sialylated structures on the neuronal plasma membrane, which warrant further investigation.
Collapse
Affiliation(s)
- Jerrard M Hayes
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Darren M O'Hara
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Gavin P Davey
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland.
| |
Collapse
|
28
|
Tremblay MÈ. Microglial functional alteration and increased diversity in the challenged brain: Insights into novel targets for intervention. Brain Behav Immun Health 2021; 16:100301. [PMID: 34589793 PMCID: PMC8474548 DOI: 10.1016/j.bbih.2021.100301] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 07/12/2021] [Accepted: 07/13/2021] [Indexed: 02/07/2023] Open
Abstract
Microglia are the resident immune cells of the central nervous system (CNS) parenchyma, which perform beneficial physiological roles across life. These immune cells actively maintain CNS health by clearing toxic debris and removing dysfunctional or degenerating cells. They also modify the wiring of neuronal circuits, by acting on the formation, modification, and elimination of synapses-the connections between neurons. Microglia furthermore recently emerged as highly diverse cells comprising several structural and functional states, indicating a far more critical involvement in orchestrating brain development, plasticity, behaviour, and cognition. Various environmental factors, together with the individual genetic predispositions, confer an increased risk for neurodevelopmental and neuropsychiatric disorders, as well as neurodegenerative diseases that include autism spectrum disorders, schizophrenia, major depressive disorder, and Alzheimer's disease, across life. Microglia are highly sensitive to chronic psychological stress, inadequate diet, viral/bacterial infection, pollution, and insufficient or altered sleep, especially during critical developmental periods, but also throughout life. These environmental challenges can compromise microglial physiological functions, resulting notably in defective neuronal circuit wiring, altered brain functional connectivity, and the onset of behavioral deficits into adolescence, adulthood, and aging. This short review provides a historical and technical perspective, notably focused on my contribution to the field, on how environmental challenges affect microglia, particularly their physiological functions, and increase their diversity, which provides novel targets for intervention.
Collapse
Affiliation(s)
- Marie-Ève Tremblay
- Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, Québec, QC, Canada
- Molecular Medicine Department, Université Laval, Québec City, QC, Canada
- Department of Neurology and Neurosurgery, McGill University, Montréal, QC, Canada
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- The Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, Canada
| |
Collapse
|
29
|
Liao H, Winkler J, Wißfeld J, Shahraz A, Klaus C, Neumann H. Low molecular weight polysialic acid prevents lipopolysaccharide-induced inflammatory dopaminergic neurodegeneration in humanized SIGLEC11 transgenic mice. Glia 2021; 69:2845-2862. [PMID: 34406679 DOI: 10.1002/glia.24073] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 08/02/2021] [Accepted: 08/04/2021] [Indexed: 01/28/2023]
Abstract
Parkinson's disease is one of the most common neurodegenerative diseases in the elderly population, with a pathophysiology linked to neuroinflammation, complement activation, and oxidative damage. Soluble polysialic acid with an average degree of polymerization 20 (polySia avDP20) prevents inflammation and oxidative burst in human macrophages via sialic acid-binding immunoglobulin like lectin-11 (SIGLEC11) receptor and interferes with alternative complement activation. Here, we confirmed the anti-inflammatory capacity of polySia avDP20 on cultured murine embryonic stem cell-derived microglia and analyzed the effect of polySia avDP20 in a lipopolysaccharide-triggered animal model of Parkinson's disease. We demonstrated a neuroprotective effect of intraperitoneally applied polySia avDP20 in humanized SIGLEC11 transgenic mice after repeated systemic challenge with lipopolysaccharide. Pathway enrichment analysis of the brain transcriptome on day 19 after disease initiation showed that intraperitoneal application of 10 μg/g body weight polySia avDP20 prevented excessive inflammation. In line with these data, polySia avDP20 attenuated the lipopolysaccharide-triggered increase in mRNA levels of immune-related genes (Il1b, Cd14, Myd88, Fcer1g, Itgam, C4, Cybb, Iba1 and Cd68) and cell death-related genes (Casp8, Ripk1 and Ripk3) in the brains of SIGLEC11 transgenic mice on day 19, but not on day 5. Moreover, immunohistochemistry demonstrated that polySia avDP20 reduced the lipopolysaccharide-induced increase in immunoreactivity of IBA1 and CD68 in the substantia nigra pars reticulata in SIGLEC11 transgenic and wild type mice on day 19. Furthermore, treatment with polySia avDP20 prevented the loss of dopaminergic neurons in the substantia nigra pars compacta induced by lipopolysaccharide challenge in both SIGLEC11 transgenic and wild type mice on day 19. Thus, our data demonstrate that polySia avDP20 ameliorates inflammatory dopaminergic neurodegeneration and therefore is a promising drug candidate to prevent Parkinson's disease-related inflammation and neurodegeneration.
Collapse
Affiliation(s)
- Huan Liao
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| | - Jonas Winkler
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| | - Jannis Wißfeld
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| | - Anahita Shahraz
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| | - Christine Klaus
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| | - Harald Neumann
- Neural Regeneration Unit, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| |
Collapse
|
30
|
Awogbindin IO, Ben-Azu B, Olusola BA, Akinluyi ET, Adeniyi PA, Di Paolo T, Tremblay MÈ. Microglial Implications in SARS-CoV-2 Infection and COVID-19: Lessons From Viral RNA Neurotropism and Possible Relevance to Parkinson's Disease. Front Cell Neurosci 2021; 15:670298. [PMID: 34211370 PMCID: PMC8240959 DOI: 10.3389/fncel.2021.670298] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Accepted: 05/05/2021] [Indexed: 12/24/2022] Open
Abstract
Since December 2019, humankind has been experiencing a ravaging severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak, the second coronavirus pandemic in a decade after the Middle East respiratory syndrome coronavirus (MERS-CoV) disease in 2012. Infection with SARS-CoV-2 results in Coronavirus disease 2019 (COVID-19), which is responsible for over 3.1 million deaths worldwide. With the emergence of a second and a third wave of infection across the globe, and the rising record of multiple reinfections and relapses, SARS-CoV-2 infection shows no sign of abating. In addition, it is now evident that SARS-CoV-2 infection presents with neurological symptoms that include early hyposmia, ischemic stroke, meningitis, delirium and falls, even after viral clearance. This may suggest chronic or permanent changes to the neurons, glial cells, and/or brain vasculature in response to SARS-CoV-2 infection or COVID-19. Within the central nervous system (CNS), microglia act as the central housekeepers against altered homeostatic states, including during viral neurotropic infections. In this review, we highlight microglial responses to viral neuroinfections, especially those with a similar genetic composition and route of entry as SARS-CoV-2. As the primary sensor of viral infection in the CNS, we describe the pathogenic and neuroinvasive mechanisms of RNA viruses and SARS-CoV-2 vis-à-vis the microglial means of viral recognition. Responses of microglia which may culminate in viral clearance or immunopathology are also covered. Lastly, we further discuss the implication of SARS-CoV-2 CNS invasion on microglial plasticity and associated long-term neurodegeneration. As such, this review provides insight into some of the mechanisms by which microglia could contribute to the pathophysiology of post-COVID-19 neurological sequelae and disorders, including Parkinson's disease, which could be pervasive in the coming years given the growing numbers of infected and re-infected individuals globally.
Collapse
Affiliation(s)
- Ifeoluwa O. Awogbindin
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Neuroimmunology Group, Molecular Drug Metabolism and Toxicology Laboratory, Department of Biochemistry, College of Medicine, University of Ibadan, Ibadan, Nigeria
| | - Benneth Ben-Azu
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Neuropharmacology Unit, Department of Pharmacology and Therapeutics, Faculty of Basic Medical Sciences, College of Health Sciences, Delta State University, Abraka, Nigeria
| | - Babatunde A. Olusola
- Department of Virology, College of Medicine, University of Ibadan, Ibadan, Nigeria
| | - Elizabeth T. Akinluyi
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Department of Pharmacology and Therapeutics, College of Medicine and Health Sciences, Afe Babalola University, Ado-Ekiti, Nigeria
| | - Philip A. Adeniyi
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, United States
| | - Therese Di Paolo
- Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, Québec, QC, Canada
- Faculté de Pharmacie, Université Laval, Québec, QC, Canada
| | - Marie-Ève Tremblay
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Axe Neurosciences, Centre de Recherche du CHU de Québec-Université Laval, Québec, QC, Canada
- Neurology and Neurosurgery Department, McGill University, Montréal, QC, Canada
- Department of Molecular Medicine, Université Laval, Québec, QC, Canada
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| |
Collapse
|
31
|
Cockram TOJ, Dundee JM, Popescu AS, Brown GC. The Phagocytic Code Regulating Phagocytosis of Mammalian Cells. Front Immunol 2021; 12:629979. [PMID: 34177884 PMCID: PMC8220072 DOI: 10.3389/fimmu.2021.629979] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 05/18/2021] [Indexed: 01/21/2023] Open
Abstract
Mammalian phagocytes can phagocytose (i.e. eat) other mammalian cells in the body if they display certain signals, and this phagocytosis plays fundamental roles in development, cell turnover, tissue homeostasis and disease prevention. To phagocytose the correct cells, phagocytes must discriminate which cells to eat using a 'phagocytic code' - a set of over 50 known phagocytic signals determining whether a cell is eaten or not - comprising find-me signals, eat-me signals, don't-eat-me signals and opsonins. Most opsonins require binding to eat-me signals - for example, the opsonins galectin-3, calreticulin and C1q bind asialoglycan eat-me signals on target cells - to induce phagocytosis. Some proteins act as 'self-opsonins', while others are 'negative opsonins' or 'phagocyte suppressants', inhibiting phagocytosis. We review known phagocytic signals here, both established and novel, and how they integrate to regulate phagocytosis of several mammalian targets - including excess cells in development, senescent and aged cells, infected cells, cancer cells, dead or dying cells, cell debris and neuronal synapses. Understanding the phagocytic code, and how it goes wrong, may enable novel therapies for multiple pathologies with too much or too little phagocytosis, such as: infectious disease, cancer, neurodegeneration, psychiatric disease, cardiovascular disease, ageing and auto-immune disease.
Collapse
Affiliation(s)
| | | | | | - Guy C. Brown
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| |
Collapse
|
32
|
Nosi D, Lana D, Giovannini MG, Delfino G, Zecchi-Orlandini S. Neuroinflammation: Integrated Nervous Tissue Response through Intercellular Interactions at the "Whole System" Scale. Cells 2021; 10:1195. [PMID: 34068375 PMCID: PMC8153304 DOI: 10.3390/cells10051195] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/07/2021] [Accepted: 05/10/2021] [Indexed: 12/12/2022] Open
Abstract
Different cell populations in the nervous tissue establish numerous, heterotypic interactions and perform specific, frequently intersecting activities devoted to the maintenance of homeostasis. Microglia and astrocytes, respectively the immune and the "housekeeper" cells of nervous tissue, play a key role in neurodegenerative diseases. Alterations of tissue homeostasis trigger neuroinflammation, a collective dynamic response of glial cells. Reactive astrocytes and microglia express various functional phenotypes, ranging from anti-inflammatory to pro-inflammatory. Chronic neuroinflammation is characterized by a gradual shift of astroglial and microglial phenotypes from anti-inflammatory to pro-inflammatory, switching their activities from cytoprotective to cytotoxic. In this scenario, the different cell populations reciprocally modulate their phenotypes through intense, reverberating signaling. Current evidence suggests that heterotypic interactions are links in an intricate network of mutual influences and interdependencies connecting all cell types in the nervous system. In this view, activation, modulation, as well as outcomes of neuroinflammation, should be ascribed to the nervous tissue as a whole. While the need remains of identifying further links in this network, a step back to rethink our view of neuroinflammation in the light of the "whole system" scale, could help us to understand some of its most controversial and puzzling features.
Collapse
Affiliation(s)
- Daniele Nosi
- Section of Histology anf Human Anatomy, Department of Experimental and Clinical Medicine, University of Florence, Largo Brambilla, 3, 50134 Florence, Italy;
| | - Daniele Lana
- Section of Clinical Pharmacology and Oncology, Department of Health Sciences, University of Florence, Viale Gaetano Pieraccini, 50139 Florence, Italy; (D.L.); (M.G.G.)
| | - Maria Grazia Giovannini
- Section of Clinical Pharmacology and Oncology, Department of Health Sciences, University of Florence, Viale Gaetano Pieraccini, 50139 Florence, Italy; (D.L.); (M.G.G.)
| | - Giovanni Delfino
- Department of Biology, University of Florence, Via Madonna del Piano, 6, 50019 Sesto Fiorentino, Florence, Italy;
| | - Sandra Zecchi-Orlandini
- Section of Histology anf Human Anatomy, Department of Experimental and Clinical Medicine, University of Florence, Largo Brambilla, 3, 50134 Florence, Italy;
| |
Collapse
|
33
|
Tuo QZ, Zhang ST, Lei P. Mechanisms of neuronal cell death in ischemic stroke and their therapeutic implications. Med Res Rev 2021; 42:259-305. [PMID: 33957000 DOI: 10.1002/med.21817] [Citation(s) in RCA: 229] [Impact Index Per Article: 76.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 03/31/2021] [Accepted: 04/23/2021] [Indexed: 02/05/2023]
Abstract
Ischemic stroke caused by arterial occlusion is the most common type of stroke, which is among the most frequent causes of disability and death worldwide. Current treatment approaches involve achieving rapid reperfusion either pharmacologically or surgically, both of which are time-sensitive; moreover, blood flow recanalization often causes ischemia/reperfusion injury. However, even though neuroprotective intervention is urgently needed in the event of stroke, the exact mechanisms of neuronal death during ischemic stroke are still unclear, and consequently, the capacity for drug development has remained limited. Multiple cell death pathways are implicated in the pathogenesis of ischemic stroke. Here, we have reviewed these potential neuronal death pathways, including intrinsic and extrinsic apoptosis, necroptosis, autophagy, ferroptosis, parthanatos, phagoptosis, and pyroptosis. We have also reviewed the latest results of pharmacological studies on ischemic stroke and summarized emerging drug targets with a focus on clinical trials. These observations may help to further understand the pathological events in ischemic stroke and bridge the gap between basic and translational research to reveal novel neuroprotective interventions.
Collapse
Affiliation(s)
- Qing-Zhang Tuo
- Department of Geriatrics and State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China
| | - Shu-Ting Zhang
- Department of Neurology and State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China
| | - Peng Lei
- Department of Neurology and State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, Chengdu, Sichuan Province, China
| |
Collapse
|
34
|
Butler CA, Popescu AS, Kitchener EJA, Allendorf DH, Puigdellívol M, Brown GC. Microglial phagocytosis of neurons in neurodegeneration, and its regulation. J Neurochem 2021; 158:621-639. [PMID: 33608912 DOI: 10.1111/jnc.15327] [Citation(s) in RCA: 118] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 01/13/2021] [Accepted: 02/10/2021] [Indexed: 02/06/2023]
Abstract
There is growing evidence that excessive microglial phagocytosis of neurons and synapses contributes to multiple brain pathologies. RNA-seq and genome-wide association (GWAS) studies have linked multiple phagocytic genes to neurodegenerative diseases, and knock-out of phagocytic genes has been found to protect against neurodegeneration in animal models, suggesting that excessive microglial phagocytosis contributes to neurodegeneration. Here, we review recent evidence that microglial phagocytosis of live neurons and synapses causes neurodegeneration in animal models of Alzheimer's disease and other tauopathies, Parkinson's disease, frontotemporal dementias, multiple sclerosis, retinal degeneration and neurodegeneration induced by ischaemia, infection or ageing. We also review factors regulating microglial phagocytosis of neurons, including: nucleotides, frackalkine, phosphatidylserine, calreticulin, UDP, CD47, sialylation, complement, galectin-3, Apolipoprotein E, phagocytic receptors, Siglec receptors, cytokines, microglial epigenetics and expression profile. Some of these factors may be potential treatment targets to prevent neurodegeneration mediated by excessive microglial phagocytosis of live neurons and synapses.
Collapse
Affiliation(s)
- Claire A Butler
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Alma S Popescu
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | | | | | - Mar Puigdellívol
- Department of Biochemistry, University of Cambridge, Cambridge, UK.,Departament de Biomedicina, Facultat de Medicina, Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
| | - Guy C Brown
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| |
Collapse
|
35
|
Fatoba O, Itokazu T, Yamashita T. Complement cascade functions during brain development and neurodegeneration. FEBS J 2021; 289:2085-2109. [PMID: 33599083 DOI: 10.1111/febs.15772] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 02/07/2021] [Accepted: 02/16/2021] [Indexed: 12/12/2022]
Abstract
The complement system, an essential tightly regulated innate immune system, is a key regulator of normal central nervous system (CNS) development and function. However, aberrant complement component expression and activation in the brain may culminate into marked neuroinflammatory response, neurodegenerative processes and cognitive impairment. Over the years, complement-mediated neuroinflammatory responses and complement-driven neurodegeneration have been increasingly implicated in the pathogenesis of a wide spectrum of CNS disorders. This review describes how complement system contributes to normal brain development and function. We also discuss how pathologic insults such as misfolded proteins, lipid droplet/lipid droplet-associated protein or glycosaminoglycan accumulation could trigger complement-mediated neuroinflammatory responses and neurodegenerative process in neurodegenerative proteinopathies, age-related macular degeneration and neurodegenerative lysosomal storage disorders.
Collapse
Affiliation(s)
- Oluwaseun Fatoba
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan.,WPI-Immunology Frontier Research Center, Osaka University, Suita, Japan
| | - Takahide Itokazu
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan.,Department of Neuro-Medical Science, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Toshihide Yamashita
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, Suita, Japan.,WPI-Immunology Frontier Research Center, Osaka University, Suita, Japan.,Department of Neuro-Medical Science, Graduate School of Medicine, Osaka University, Suita, Japan
| |
Collapse
|
36
|
Nakić N, Tran TH, Novokmet M, Andreoletti O, Lauc G, Legname G. Site-specific analysis of N-glycans from different sheep prion strains. PLoS Pathog 2021; 17:e1009232. [PMID: 33600485 PMCID: PMC7891774 DOI: 10.1371/journal.ppat.1009232] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 12/10/2020] [Indexed: 01/23/2023] Open
Abstract
Prion diseases are a group of neurodegenerative diseases affecting a wide range of mammalian species, including humans. During the course of the disease, the abnormally folded scrapie prion protein (PrPSc) accumulates in the central nervous system where it causes neurodegeneration. In prion disorders, the diverse spectrum of illnesses exists because of the presence of different isoforms of PrPSc where they occupy distinct conformational states called strains. Strains are biochemically distinguished by a characteristic three-band immunoblot pattern, defined by differences in the occupancy of two glycosylation sites on the prion protein (PrP). Characterization of the exact N-glycan structures attached on either PrPC or PrPSc is lacking. Here we report the characterization and comparison of N-glycans from two different sheep prion strains. PrPSc from both strains was isolated from brain tissue and enzymatically digested with trypsin. By using liquid chromatography coupled to electrospray mass spectrometry, a site-specific analysis was performed. A total of 100 structures were detected on both glycosylation sites. The N-glycan profile was shown to be similar to the one on mouse PrP, however, with additional 40 structures reported. The results presented here show no major differences in glycan composition, suggesting that glycans may not be responsible for the differences in the two analyzed prion strains. To date, prion diseases remain a controversy amongst scientists. Although we know now it is the abnormal form of the prion protein (PrPSc) that causes the disease, many questions are still left unanswered. To understand the cellular mechanism of these diseases, we should first and foremost try to fully understand the prion protein itself. Even though many findings have been made regarding the structure of the protein, a large part of it is still unknown. Since the prion protein is actually a glycoprotein, to resolve its structure we need to put our focus not only on the protein part of the glycoprotein but also on the glycan structures as well. Here we compared two different sheep prion strains and although no major differences have been found between the glycan structures, this analysis may help the understanding of the role glycans have in prion diseases.
Collapse
Affiliation(s)
- Natali Nakić
- Genos Glycoscience Research Laboratory, Zagreb, Croatia.,Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Thanh Hoa Tran
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy.,VNUK Institute for Research and Executive Education, The University of Danang, Da Nang, Vietnam
| | | | - Olivier Andreoletti
- UMR INRA ENVT 1225-IHAP, École Nationale Vétérinaire de Toulouse, Toulouse, France
| | - Gordan Lauc
- Genos Glycoscience Research Laboratory, Zagreb, Croatia.,Faculty of Pharmacy and Biochemistry, University of Zagreb, Zagreb, Croatia
| | - Giuseppe Legname
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy.,ELETTRA Sincrotrone Trieste S.C.p.A., Basovizza, Trieste, Italy
| |
Collapse
|
37
|
Kovács RÁ, Vadászi H, Bulyáki É, Török G, Tóth V, Mátyás D, Kun J, Hunyadi-Gulyás É, Fedor FZ, Csincsi Á, Medzihradszky K, Homolya L, Juhász G, Kékesi KA, Józsi M, Györffy BA, Kardos J. Identification of Neuronal Pentraxins as Synaptic Binding Partners of C1q and the Involvement of NP1 in Synaptic Pruning in Adult Mice. Front Immunol 2021; 11:599771. [PMID: 33628204 PMCID: PMC7897678 DOI: 10.3389/fimmu.2020.599771] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 12/21/2020] [Indexed: 12/13/2022] Open
Abstract
Elements of the immune system particularly that of innate immunity, play important roles beyond their traditional tasks in host defense, including manifold roles in the nervous system. Complement-mediated synaptic pruning is essential in the developing and healthy functioning brain and becomes aberrant in neurodegenerative disorders. C1q, component of the classical complement pathway, plays a central role in tagging synapses for elimination; however, the underlying molecular mechanisms and interaction partners are mostly unknown. Neuronal pentraxins (NPs) are involved in synapse formation and plasticity, moreover, NP1 contributes to cell death and neurodegeneration under adverse conditions. Here, we investigated the potential interaction between C1q and NPs, and its role in microglial phagocytosis of synapses in adult mice. We verified in vitro that NPs interact with C1q, as well as activate the complement system. Flow cytometry, immunostaining and co-immunoprecipitation showed that synapse-bound C1q colocalizes and interacts with NPs. High-resolution confocal microscopy revealed that microglia-surrounded C1q-tagged synapses are NP1 positive. We have also observed the synaptic occurrence of C4 suggesting that activation of the classical pathway cannot be ruled out in synaptic plasticity in healthy adult animals. In summary, our results indicate that NPs play a regulatory role in the synaptic function of C1q. Whether this role can be intensified upon pathological conditions, such as in Alzheimer’s disease, is to be disclosed.
Collapse
Affiliation(s)
- Réka Á Kovács
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Henrietta Vadászi
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Éva Bulyáki
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - György Török
- Molecular Cell Biology Research Group, Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Centre of Excellence, Budapest, Hungary.,Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - Vilmos Tóth
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary.,Laboratory of Proteomics, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Dominik Mátyás
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary.,Laboratory of Proteomics, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Judit Kun
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Éva Hunyadi-Gulyás
- Laboratory of Proteomics Research, Biological Research Centre, Eötvös Loránd Research Network (ELKH), Szeged, Hungary
| | - Flóra Zsófia Fedor
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary.,Doctoral School of Chemical Engineering and Material Sciences, Pannon University, Veszprém, Hungary
| | - Ádám Csincsi
- Complement Research Group, Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Katalin Medzihradszky
- Laboratory of Proteomics Research, Biological Research Centre, Eötvös Loránd Research Network (ELKH), Szeged, Hungary
| | - László Homolya
- Molecular Cell Biology Research Group, Institute of Enzymology, Research Center for Natural Sciences, Hungarian Academy of Sciences Centre of Excellence, Budapest, Hungary
| | - Gábor Juhász
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary.,Laboratory of Proteomics, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Katalin A Kékesi
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary.,Laboratory of Proteomics, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary.,Department of Physiology and Neurobiology, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Mihály Józsi
- Complement Research Group, Department of Immunology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - Balázs A Györffy
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary.,Laboratory of Proteomics, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| | - József Kardos
- ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest, Hungary
| |
Collapse
|
38
|
Wißfeld J, Nozaki I, Mathews M, Raschka T, Ebeling C, Hornung V, Brüstle O, Neumann H. Deletion of Alzheimer's disease-associated CD33 results in an inflammatory human microglia phenotype. Glia 2021; 69:1393-1412. [PMID: 33539598 DOI: 10.1002/glia.23968] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 01/05/2021] [Accepted: 01/08/2021] [Indexed: 12/13/2022]
Abstract
Genome-wide association studies demonstrated that polymorphisms in the CD33/sialic acid-binding immunoglobulin-like lectin 3 gene are associated with late-onset Alzheimer's disease (AD). CD33 is expressed on myeloid immune cells and mediates inhibitory signaling through protein tyrosine phosphatases, but the exact function of CD33 in microglia is still unknown. Here, we analyzed CD33 knockout human THP1 macrophages and human induced pluripotent stem cell-derived microglia for immunoreceptor tyrosine-based activation motif pathway activation, cytokine transcription, phagocytosis, and phagocytosis-associated oxidative burst. Transcriptome analysis of the macrophage lines showed that knockout of CD33 as well as knockdown of the CD33 signaling-associated protein tyrosine phosphatase, nonreceptor type 6 (PTPN6) led to constitutive activation of inflammation-related pathways. Moreover, deletion of CD33 or expression of Exon 2-deleted CD33 (CD33ΔE2 /CD33m) led to increased phosphorylation of the kinases spleen tyrosine kinase (SYK) and extracellular signal-regulated kinase 1 and 2 (ERK1 and 2). Transcript analysis by quantitative real-time polymerase chain reaction confirmed increased levels of interleukin (IL) 1B, IL8, and IL10 after knockout of CD33 in macrophages and microglia. In addition, upregulation of the gene transcripts of the AD-associated phosphatase INPP5D was observed after knockout of CD33. Functional analysis of macrophages and microglia showed that phagocytosis of aggregated amyloid-β1-42 and bacterial particles were increased after knockout of CD33 or CD33ΔE2 expression and knockdown of PTPN6. Furthermore, the phagocytic oxidative burst during uptake of amyloid-β1-42 or bacterial particles was increased after CD33 knockout but not in CD33ΔE2 -expressing microglia. In summary, deletion of CD33 or expression of CD33ΔE2 in human macrophages and microglia resulted in putative beneficial phagocytosis of amyloid β1-42 , but potentially detrimental oxidative burst and inflammation, which was absent in CD33ΔE2 -expressing microglia.
Collapse
Affiliation(s)
- Jannis Wißfeld
- Institute of Reconstructive Neurobiology, University of Bonn Medical Faculty and University Hospital Bonn, Bonn, Germany
| | - Ichiro Nozaki
- Institute of Reconstructive Neurobiology, University of Bonn Medical Faculty and University Hospital Bonn, Bonn, Germany.,Department of Neurology and Neurobiology of Aging, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Mona Mathews
- Institute of Reconstructive Neurobiology, University of Bonn Medical Faculty and University Hospital Bonn, Bonn, Germany.,LIFE & BRAIN GmbH, Cellomics Unit, Bonn, Germany
| | - Tamara Raschka
- Department of Bioinformatics, Fraunhofer Institute for Algorithms and Scientific Computing, Sankt Augustin, Germany
| | - Christian Ebeling
- Department of Bioinformatics, Fraunhofer Institute for Algorithms and Scientific Computing, Sankt Augustin, Germany
| | - Veit Hornung
- Institute of Molecular Medicine, University of Bonn Medical Faculty and University Hospital Bonn, Bonn, Germany
| | - Oliver Brüstle
- Institute of Reconstructive Neurobiology, University of Bonn Medical Faculty and University Hospital Bonn, Bonn, Germany.,LIFE & BRAIN GmbH, Cellomics Unit, Bonn, Germany
| | - Harald Neumann
- Institute of Reconstructive Neurobiology, University of Bonn Medical Faculty and University Hospital Bonn, Bonn, Germany
| |
Collapse
|
39
|
Ermakov EA, Dmitrieva EM, Parshukova DA, Kazantseva DV, Vasilieva AR, Smirnova LP. Oxidative Stress-Related Mechanisms in Schizophrenia Pathogenesis and New Treatment Perspectives. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:8881770. [PMID: 33552387 PMCID: PMC7847339 DOI: 10.1155/2021/8881770] [Citation(s) in RCA: 85] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 12/15/2020] [Accepted: 01/02/2021] [Indexed: 02/07/2023]
Abstract
Schizophrenia is recognized to be a highly heterogeneous disease at various levels, from genetics to clinical manifestations and treatment sensitivity. This heterogeneity is also reflected in the variety of oxidative stress-related mechanisms contributing to the phenotypic realization and manifestation of schizophrenia. At the molecular level, these mechanisms are supposed to include genetic causes that increase the susceptibility of individuals to oxidative stress and lead to gene expression dysregulation caused by abnormal regulation of redox-sensitive transcriptional factors, noncoding RNAs, and epigenetic mechanisms favored by environmental insults. These changes form the basis of the prooxidant state and lead to altered redox signaling related to glutathione deficiency and impaired expression and function of redox-sensitive transcriptional factors (Nrf2, NF-κB, FoxO, etc.). At the cellular level, these changes lead to mitochondrial dysfunction and metabolic abnormalities that contribute to aberrant neuronal development, abnormal myelination, neurotransmitter anomalies, and dysfunction of parvalbumin-positive interneurons. Immune dysfunction also contributes to redox imbalance. At the whole-organism level, all these mechanisms ultimately contribute to the manifestation and development of schizophrenia. In this review, we consider oxidative stress-related mechanisms and new treatment perspectives associated with the correction of redox imbalance in schizophrenia. We suggest that not only antioxidants but also redox-regulated transcription factor-targeting drugs (including Nrf2 and FoxO activators or NF-κB inhibitors) have great promise in schizophrenia. But it is necessary to develop the stratification criteria of schizophrenia patients based on oxidative stress-related markers for the administration of redox-correcting treatment.
Collapse
Affiliation(s)
- Evgeny A. Ermakov
- Laboratory of Repair Enzymes, Institute of Chemical Biology and Fundamental Medicine, Siberian Division of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Elena M. Dmitrieva
- Laboratory of Molecular Genetics and Biochemistry, Mental Health Research Institute, Tomsk National Research Medical Center of the Russian Academy of Sciences, Tomsk 634014, Russia
| | - Daria A. Parshukova
- Laboratory of Molecular Genetics and Biochemistry, Mental Health Research Institute, Tomsk National Research Medical Center of the Russian Academy of Sciences, Tomsk 634014, Russia
| | | | | | - Liudmila P. Smirnova
- Laboratory of Molecular Genetics and Biochemistry, Mental Health Research Institute, Tomsk National Research Medical Center of the Russian Academy of Sciences, Tomsk 634014, Russia
| |
Collapse
|
40
|
Klaus C, Liao H, Allendorf DH, Brown GC, Neumann H. Sialylation acts as a checkpoint for innate immune responses in the central nervous system. Glia 2020; 69:1619-1636. [PMID: 33340149 DOI: 10.1002/glia.23945] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/23/2020] [Accepted: 11/26/2020] [Indexed: 12/28/2022]
Abstract
Sialic acids are monosaccharides that normally terminate the glycan chains of cell surface glyco-proteins and -lipids in mammals, and are highly enriched in the central nervous tissue. Sialic acids are conjugated to proteins and lipids (termed "sialylation") by specific sialyltransferases, and are removed ("desialylation") by neuraminidases. Cell surface sialic acids are sensed by complement factor H (FH) to inhibit complement activation or by sialic acid-binding immunoglobulin-like lectin (SIGLEC) receptors to inhibit microglial activation, phagocytosis, and oxidative burst. In contrast, desialylation of cells enables binding of the opsonins C1, calreticulin, galectin-3, and collectins, stimulating phagocytosis of such cells. Hypersialylation is used by bacteria and cancers as camouflage to escape immune recognition, while polysialylation of neurons protects synapses and neurogenesis. Insufficient lysosomal cleavage of sialylated molecules can lead to lysosomal accumulation of lipids and aggregated proteins, which if excessive may be expelled into the extracellular space. On the other hand, desialylation of immune receptors can activate them or trigger removal of proteins. Loss of inhibitory SIGLECs or FH triggers reduced clearance of aggregates, oxidative brain damage and complement-mediated retinal damage. Thus, cell surface sialylation recognized by FH, SIGLEC, and other immune-related receptors acts as a major checkpoint inhibitor of innate immune responses in the central nervous system, while excessive cleavage of sialic acid residues and consequently removing this checkpoint inhibitor may trigger lipid accumulation, protein aggregation, inflammation, and neurodegeneration.
Collapse
Affiliation(s)
- Christine Klaus
- Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| | - Huan Liao
- Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| | | | - Guy C Brown
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Harald Neumann
- Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| |
Collapse
|
41
|
Mealer RG, Williams SE, Daly MJ, Scolnick EM, Cummings RD, Smoller JW. Glycobiology and schizophrenia: a biological hypothesis emerging from genomic research. Mol Psychiatry 2020; 25:3129-3139. [PMID: 32377000 PMCID: PMC8081046 DOI: 10.1038/s41380-020-0753-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 04/09/2020] [Accepted: 04/22/2020] [Indexed: 12/12/2022]
Abstract
Advances in genomics are opening new windows into the biology of schizophrenia. Though common variants individually have small effects on disease risk, GWAS provide a powerful opportunity to explore pathways and mechanisms contributing to pathophysiology. Here, we highlight an underappreciated biological theme emerging from GWAS: the role of glycosylation in schizophrenia. The strongest coding variant in schizophrenia GWAS is a missense mutation in the manganese transporter SLC39A8, which is associated with altered glycosylation patterns in humans. Furthermore, variants near several genes encoding glycosylation enzymes are unambiguously associated with schizophrenia: FUT9, MAN2A1, TMTC1, GALNT10, and B3GAT1. Here, we summarize the known biological functions, target substrates, and expression patterns of these enzymes as a primer for future studies. We also highlight a subset of schizophrenia-associated proteins critically modified by glycosylation including glutamate receptors, voltage-gated calcium channels, the dopamine D2 receptor, and complement glycoproteins. We hypothesize that common genetic variants alter brain glycosylation and play a fundamental role in the development of schizophrenia. Leveraging these findings will advance our mechanistic understanding of disease and may provide novel avenues for treatment development.
Collapse
Affiliation(s)
- Robert G. Mealer
- Massachusetts General Hospital, Department of Psychiatry.,The Stanley Center for Psychiatric Research at Broad Institute.,Department of Surgery, Beth Israel Deaconess Medical Center. Harvard Medical School, Boston MA.,Corresponding Author: Robert Gene Mealer, M.D., Ph.D., Richard B. Simches Research Center, 185 Cambridge St, 6th Floor, Boston, MA 02114, Tel: +1 (617) 724-9076,
| | - Sarah E. Williams
- Massachusetts General Hospital, Department of Psychiatry.,Department of Surgery, Beth Israel Deaconess Medical Center. Harvard Medical School, Boston MA
| | - Mark J. Daly
- Massachusetts General Hospital, Department of Psychiatry.,The Stanley Center for Psychiatric Research at Broad Institute
| | - Edward M. Scolnick
- Massachusetts General Hospital, Department of Psychiatry.,The Stanley Center for Psychiatric Research at Broad Institute
| | - Richard D. Cummings
- Department of Surgery, Beth Israel Deaconess Medical Center. Harvard Medical School, Boston MA
| | - Jordan W. Smoller
- Massachusetts General Hospital, Department of Psychiatry.,The Stanley Center for Psychiatric Research at Broad Institute
| |
Collapse
|
42
|
Schartz ND, Tenner AJ. The good, the bad, and the opportunities of the complement system in neurodegenerative disease. J Neuroinflammation 2020; 17:354. [PMID: 33239010 PMCID: PMC7690210 DOI: 10.1186/s12974-020-02024-8] [Citation(s) in RCA: 136] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 11/04/2020] [Indexed: 02/06/2023] Open
Abstract
The complement cascade is a critical effector mechanism of the innate immune system that contributes to the rapid clearance of pathogens and dead or dying cells, as well as contributing to the extent and limit of the inflammatory immune response. In addition, some of the early components of this cascade have been clearly shown to play a beneficial role in synapse elimination during the development of the nervous system, although excessive complement-mediated synaptic pruning in the adult or injured brain may be detrimental in multiple neurogenerative disorders. While many of these later studies have been in mouse models, observations consistent with this notion have been reported in human postmortem examination of brain tissue. Increasing awareness of distinct roles of C1q, the initial recognition component of the classical complement pathway, that are independent of the rest of the complement cascade, as well as the relationship with other signaling pathways of inflammation (in the periphery as well as the central nervous system), highlights the need for a thorough understanding of these molecular entities and pathways to facilitate successful therapeutic design, including target identification, disease stage for treatment, and delivery in specific neurologic disorders. Here, we review the evidence for both beneficial and detrimental effects of complement components and activation products in multiple neurodegenerative disorders. Evidence for requisite co-factors for the diverse consequences are reviewed, as well as the recent studies that support the possibility of successful pharmacological approaches to suppress excessive and detrimental complement-mediated chronic inflammation, while preserving beneficial effects of complement components, to slow the progression of neurodegenerative disease.
Collapse
Affiliation(s)
- Nicole D. Schartz
- Department of Molecular Biology and Biochemistry, University of California Irvine, 3205 McGaugh Hall, Irvine, CA 92697 USA
| | - Andrea J. Tenner
- Department of Molecular Biology and Biochemistry, University of California Irvine, 3205 McGaugh Hall, Irvine, CA 92697 USA
- Department of Neurobiology and Behavior, University of California Irvine, 3205 McGaugh Hall, Irvine, CA 92697 USA
- Department of Pathology and Laboratory Medicine, University of California Irvine, 3205 McGaugh Hall, Irvine, CA 92697 USA
| |
Collapse
|
43
|
Baskakov IV. Role of sialylation in prion disease pathogenesis and prion structure. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 175:31-52. [PMID: 32958238 DOI: 10.1016/bs.pmbts.2020.07.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Mammalian prion or PrPSc is a proteinaceous infectious agent that consists of a misfolded, self-replicating state of a sialoglycoprotein called the prion protein or PrPC. Sialylation of the prion protein, a terminal modification of N-linked glycans, was discovered more than 30 years ago, yet the role of sialylation in prion pathogenesis is not well understood. This chapter summarizes current knowledge on the role of sialylation of the prion protein in prion diseases. First, we discuss recent data suggesting that sialylation of PrPSc N-linked glycans determines the fate of prion infection in an organism and control prion lymphotropism. Second, emerging evidence pointing out at the role N-glycans in neuroinflammation are discussed. Thirds, this chapter reviews a mechanism postulating that sialylated N-linked glycans are important players in defining strain-specific structures. A new hypothesis according to which individual strain-specific PrPSc structures govern selection of PrPC sialoglycoforms is discussed. Finally, this chapter explain how N-glycan sialylation control the prion replication and strain interference. In summary, comprehensive review of our knowledge on N-linked glycans and their sialylation provided in this chapter helps to answer important questions of prion biology that have been puzzling for years.
Collapse
Affiliation(s)
- Ilia V Baskakov
- Department of Anatomy and Neurobiology, and Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, United States.
| |
Collapse
|
44
|
Makarava N, Chang JCY, Molesworth K, Baskakov IV. Posttranslational modifications define course of prion strain adaptation and disease phenotype. J Clin Invest 2020; 130:4382-4395. [PMID: 32484800 PMCID: PMC7410085 DOI: 10.1172/jci138677] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 05/13/2020] [Indexed: 12/13/2022] Open
Abstract
Posttranslational modifications are a common feature of proteins associated with neurodegenerative diseases including prion protein (PrPC), tau, and α-synuclein. Alternative self-propagating protein states or strains give rise to different disease phenotypes and display strain-specific subsets of posttranslational modifications. The relationships between strain-specific structure, posttranslational modifications, and disease phenotype are poorly understood. We previously reported that among hundreds of PrPC sialoglycoforms expressed by a cell, individual prion strains recruited PrPC molecules selectively, according to the sialylation status of their N-linked glycans. Here we report that transmission of a prion strain to a new host is accompanied by a dramatic shift in the selectivity of recruitment of PrPC sialoglycoforms, giving rise to a self-propagating scrapie isoform (PrPSc) with a unique sialoglycoform signature and disease phenotype. The newly emerged strain has the shortest incubation time to disease and is characterized by colocalization of PrPSc with microglia and a very profound proinflammatory response, features that are linked to a unique sialoglycoform composition of PrPSc. The current work provides experimental support for the hypothesis that strain-specific patterns of PrPSc sialoglycoforms formed as a result of selective recruitment dictate strain-specific disease phenotypes. This work suggests a causative relationship between a strain-specific structure, posttranslational modifications, and disease phenotype.
Collapse
Affiliation(s)
- Natallia Makarava
- Center for Biomedical Engineering and Technology and
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Jennifer Chen-Yu Chang
- Center for Biomedical Engineering and Technology and
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Kara Molesworth
- Center for Biomedical Engineering and Technology and
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Ilia V. Baskakov
- Center for Biomedical Engineering and Technology and
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| |
Collapse
|
45
|
Liao H, Klaus C, Neumann H. Control of Innate Immunity by Sialic Acids in the Nervous Tissue. Int J Mol Sci 2020; 21:ijms21155494. [PMID: 32752058 PMCID: PMC7432451 DOI: 10.3390/ijms21155494] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/27/2020] [Accepted: 07/28/2020] [Indexed: 12/11/2022] Open
Abstract
Sialic acids (Sias) are the most abundant terminal sugar residues of glycoproteins and glycolipids on the surface of mammalian cells. The nervous tissue is the organ with the highest expression level of Sias. The ‘sialylation’ of glycoconjugates is performed via sialyltransferases, whereas ‘desialylation’ is done by sialidases or is a possible consequence of oxidative damage. Sialic acid residues on the neural cell surfaces inhibit complement and microglial activation, as well as phagocytosis of the underlying structures, via binding to (i) complement factor H (CFH) or (ii) sialic acid-binding immunoglobulin-like lectin (SIGLEC) receptors. In contrast, activated microglial cells show sialidase activity that desialylates both microglia and neurons, and further stimulates innate immunity via microglia and complement activation. The desialylation conveys neurons to become susceptible to phagocytosis, as well as triggers a microglial phagocytosis-associated oxidative burst and inflammation. Dysfunctions of the ‘Sia–SIGLEC’ and/or ‘Sia–complement’ axes often lead to neurological diseases. Thus, Sias on glycoconjugates of the intact glycocalyx and its desialylation are major regulators of neuroinflammation.
Collapse
Affiliation(s)
| | | | - Harald Neumann
- Correspondence: ; Tel.: +49-228-6885-500; Fax: +49-228-6885-501
| |
Collapse
|
46
|
Puigdellívol M, Allendorf DH, Brown GC. Sialylation and Galectin-3 in Microglia-Mediated Neuroinflammation and Neurodegeneration. Front Cell Neurosci 2020; 14:162. [PMID: 32581723 PMCID: PMC7296093 DOI: 10.3389/fncel.2020.00162] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 05/15/2020] [Indexed: 12/31/2022] Open
Abstract
Microglia are brain macrophages that mediate neuroinflammation and contribute to and protect against neurodegeneration. The terminal sugar residue of all glycoproteins and glycolipids on the surface of mammalian cells is normally sialic acid, and addition of this negatively charged residue is known as “sialylation,” whereas removal by sialidases is known as “desialylation.” High sialylation of the neuronal cell surface inhibits microglial phagocytosis of such neurons, via: (i) activating sialic acid receptors (Siglecs) on microglia that inhibit phagocytosis and (ii) inhibiting binding of opsonins C1q, C3, and galectin-3. Microglial sialylation inhibits inflammatory activation of microglia via: (i) activating Siglec receptors CD22 and CD33 on microglia that inhibit phagocytosis and (ii) inhibiting Toll-like receptor 4 (TLR4), complement receptor 3 (CR3), and other microglial receptors. When activated, microglia release a sialidase activity that desialylates both microglia and neurons, activating the microglia and rendering the neurons susceptible to phagocytosis. Activated microglia also release galectin-3 (Gal-3), which: (i) further activates microglia via binding to TLR4 and TREM2, (ii) binds to desialylated neurons opsonizing them for phagocytosis via Mer tyrosine kinase, and (iii) promotes Aβ aggregation and toxicity in vivo. Gal-3 and desialylation may increase in a variety of brain pathologies. Thus, Gal-3 and sialidases are potential treatment targets to prevent neuroinflammation and neurodegeneration.
Collapse
Affiliation(s)
- Mar Puigdellívol
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - David H Allendorf
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Guy C Brown
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| |
Collapse
|
47
|
Ward H, West SJ. Microglia: sculptors of neuropathic pain? ROYAL SOCIETY OPEN SCIENCE 2020; 7:200260. [PMID: 32742693 PMCID: PMC7353970 DOI: 10.1098/rsos.200260] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 06/01/2020] [Indexed: 05/02/2023]
Abstract
Neuropathic pain presents a huge societal and individual burden. The limited efficacy of current analgesics, diagnostic markers and clinical trial outcome measures arises from an incomplete understanding of the underlying mechanisms. A large and growing body of evidence has established the important role of microglia in the onset and possible maintenance of neuropathic pain, and these cells may represent an important target for future therapy. Microglial research has further revealed their important role in structural remodelling of the nervous system. In this review, we aim to explore the evidence for microglia in sculpting nervous system structure and function, as well as their important role in neuropathic pain, and finally integrate these studies to synthesize a new model for microglia in somatosensory circuit remodelling, composed of six key and inter-related mechanisms. Summarizing the mechanisms through which microglia modulate nervous system structure and function helps to frame a better understanding of neuropathic pain, and provide a clear roadmap for future research.
Collapse
Affiliation(s)
- Harry Ward
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Steven J. West
- Sainsbury Wellcome Centre, University College London, 25 Howland St, London WC1E 6BT, UK
- Author for correspondence: Steven J. West e-mail:
| |
Collapse
|
48
|
Region-specific glial homeostatic signature in prion diseases is replaced by a uniform neuroinflammation signature, common for brain regions and prion strains with different cell tropism. Neurobiol Dis 2020; 137:104783. [PMID: 32001329 DOI: 10.1016/j.nbd.2020.104783] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 01/21/2020] [Accepted: 01/25/2020] [Indexed: 02/08/2023] Open
Abstract
Chronic neuroinflammation is recognized as a major neuropathological hallmark in a broad spectrum of neurodegenerative diseases including Alzheimer's, Parkinson's, Frontal Temporal Dementia, Amyotrophic Lateral Sclerosis, and prion diseases. Both microglia and astrocytes exhibit region-specific homeostatic transcriptional identities, which under chronic neurodegeneration, transform into reactive phenotypes in a region- and disease-specific manner. Little is known about region-specific identity of glia in prion diseases. The current study was designed to determine whether the region-specific homeostatic signature of glia changes with the progression of prion diseases, and whether these changes occur in a region-dependent or universal manner. Also of interest was whether different prion strains give rise to different reactive phenotypes. To answer these questions, we analyzed gene expression in the thalamus, cortex, hypothalamus and hippocampus of mice infected with 22L and ME7 prion strains using a Nanostring Neuroinflammation panel at the subclinical, early clinical and advanced stages of the disease. We found that at the preclinical stage of the disease, the region-specific homeostatic identities were preserved. However, with the appearance of clinical signs, the region-specific signatures were partially lost and replaced with a neuroinflammation signature. While the same sets of genes were activated by both prion strains, the timing of neuroinflammation and the degree of activation in different brain regions was strain-specific. Changes in astrocyte function scored at the top of the activated pathways. Moreover, clustering analysis suggested that the astrocyte function pathway responded to prion infection prior to the Activated Microglia or Neuron and Neurotransmission pathways. The current work established neuroinflammation gene expression signature associated with prion diseases. Our results illustrate that with the disease progression, the region-specific homeostatic transcriptome signatures are replaced by the region-independent neuroinflammation signature, which is common for prion strains with different cell tropism. The prion-associated neuroinflammation signature identified in the current study overlapped only partially with the microglia degenerative phenotype and the disease-associated microglia phenotype reported for animal models of other neurodegenerative diseases.
Collapse
|
49
|
Klaus C, Hansen JN, Ginolhac A, Gérard D, Gnanapragassam VS, Horstkorte R, Rossdam C, Buettner FFR, Sauter T, Sinkkonen L, Neumann H, Linnartz-Gerlach B. Reduced sialylation triggers homeostatic synapse and neuronal loss in middle-aged mice. Neurobiol Aging 2020; 88:91-107. [PMID: 32087947 DOI: 10.1016/j.neurobiolaging.2020.01.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 01/06/2020] [Accepted: 01/14/2020] [Indexed: 12/21/2022]
Abstract
Sialic acid-binding Ig-like lectin (Siglec) receptors are linked to neurodegenerative processes, but the role of sialic acids in physiological aging is still not fully understood. We investigated the impact of reduced sialylation in the brain of mice heterozygous for the enzyme glucosamine-2-epimerase/N-acetylmannosamine kinase (GNE+/-) that is essential for sialic acid biosynthesis. We demonstrate that GNE+/- mice have hyposialylation in different brain regions, less synapses in the hippocampus and reduced microglial arborization already at 6 months followed by increased loss of neurons at 12 months. A transcriptomic analysis revealed no pro-inflammatory changes indicating an innate homeostatic immune process leading to the removal of synapses and neurons in GNE+/- mice during aging. Crossbreeding with complement C3-deficient mice rescued the earlier onset of neuronal and synaptic loss as well as the changes in microglial arborization. Thus, sialic acids of the glycocalyx contribute to brain homeostasis and act as a recognition system for the innate immune system in the brain.
Collapse
Affiliation(s)
- Christine Klaus
- Neural Regeneration, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| | - Jan N Hansen
- Biophysical Imaging, Institute of Innate Immunity, Medical Faculty, University of Bonn, Bonn, Germany
| | - Aurélien Ginolhac
- Epigenetics Team, Systems Biology Group, Life Sciences Research Unit, University of Luxembourg, Belvaux, Luxembourg
| | - Deborah Gérard
- Epigenetics Team, Systems Biology Group, Life Sciences Research Unit, University of Luxembourg, Belvaux, Luxembourg
| | - Vinayaga S Gnanapragassam
- Institute for Physiological Chemistry, Medical Faculty, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Rüdiger Horstkorte
- Institute for Physiological Chemistry, Medical Faculty, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Charlotte Rossdam
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Falk F R Buettner
- Institute of Clinical Biochemistry, Hannover Medical School, Hannover, Germany
| | - Thomas Sauter
- Epigenetics Team, Systems Biology Group, Life Sciences Research Unit, University of Luxembourg, Belvaux, Luxembourg
| | - Lasse Sinkkonen
- Epigenetics Team, Systems Biology Group, Life Sciences Research Unit, University of Luxembourg, Belvaux, Luxembourg
| | - Harald Neumann
- Neural Regeneration, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany.
| | - Bettina Linnartz-Gerlach
- Neural Regeneration, Institute of Reconstructive Neurobiology, Medical Faculty and University Hospital of Bonn, University of Bonn, Bonn, Germany
| |
Collapse
|
50
|
Allendorf DH, Puigdellívol M, Brown GC. Activated microglia desialylate their surface, stimulating complement receptor 3-mediated phagocytosis of neurons. Glia 2019; 68:989-998. [PMID: 31774586 PMCID: PMC7079032 DOI: 10.1002/glia.23757] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 11/13/2019] [Accepted: 11/15/2019] [Indexed: 12/30/2022]
Abstract
The glycoproteins and glycolipids of the cell surface have sugar chains that normally terminate in a sialic acid residue, but inflammatory activation of myeloid cells can cause sialidase enzymes to remove these residues, resulting in desialylation and altered activity of surface receptors, such as the phagocytic complement receptor 3 (CR3). We found that activation of microglia with lipopolysaccharide (LPS), fibrillar amyloid beta (Aβ), Tau or phorbol myristate acetate resulted in increased surface sialidase activity and desialylation of the microglial surface. Desialylation of microglia by adding sialidase, stimulated microglial phagocytosis of beads, but this was prevented by siRNA knockdown of CD11b or a blocking antibody to CD11b (a component of CR3). Desialylation of microglia by a sialyl-transferase inhibitor (3FAx-peracetyl-Neu5Ac) also stimulated microglial phagocytosis of beads. Desialylation of primary glial-neuronal co-cultures by adding sialidase or the sialyl-transferase inhibitor resulted in neuronal loss that was prevented by inhibiting phagocytosis with cytochalasin D or the blocking antibody to CD11b. Adding desialylated microglia to glial-neuronal cultures, in the absence of neuronal desialylation, also caused neuronal loss prevented by CD11b blocking antibody. Adding LPS or Aβ to primary glial-neuronal co-cultures caused neuronal loss, and this was prevented by inhibiting endogenous sialidase activity with N-acetyl-2,3-dehydro-2-deoxyneuraminic acid or blockage of CD11b. Thus, activated microglia release a sialidase activity that desialylates the cell surface, stimulating CR3-mediated phagocytosis of neurons, making extracellular sialidase and CR3 potential treatment targets to prevent inflammatory loss of neurons.
Collapse
Affiliation(s)
| | - Mar Puigdellívol
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Guy C Brown
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| |
Collapse
|