1
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Vepřek NA, Cooper MH, Laprell L, Yang EJN, Folkerts S, Bao R, Boczkowska M, Palmer NJ, Dominguez R, Oertner TG, Pon LA, Zuchero JB, Trauner DH. Optical Control of G-Actin with a Photoswitchable Latrunculin. J Am Chem Soc 2024; 146:8895-8903. [PMID: 38511265 PMCID: PMC11302737 DOI: 10.1021/jacs.3c10776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/22/2024]
Abstract
Actin is one of the most abundant proteins in eukaryotic cells and is a key component of the cytoskeleton. A range of small molecules has emerged that interfere with actin dynamics by either binding to polymeric F-actin or monomeric G-actin to stabilize or destabilize filaments or prevent their formation and growth, respectively. Among these, the latrunculins, which bind to G-actin and affect polymerization, are widely used as tools to investigate actin-dependent cellular processes. Here, we report a photoswitchable version of latrunculin, termed opto-latrunculin (OptoLat), which binds to G-actin in a light-dependent fashion and affords optical control over actin polymerization. OptoLat can be activated with 390-490 nm pulsed light and rapidly relaxes to its inactive form in the dark. Light activated OptoLat induced depolymerization of F-actin networks in oligodendrocytes and budding yeast, as shown by fluorescence microscopy. Subcellular control of actin dynamics in human cancer cell lines was demonstrated via live cell imaging. Light-activated OptoLat also reduced microglia surveillance in organotypic mouse brain slices while ramification was not affected. Incubation in the dark did not alter the structural and functional integrity of the microglia. Together, our data demonstrate that OptoLat is a useful tool for the elucidation of G-actin dependent dynamic processes in cells and tissues.
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Affiliation(s)
- Nynke A. Vepřek
- Department of Chemistry, New York University, New York, NY 10003, USA
- Department of Chemistry, Ludwig Maximilian University, D-80539 Munich, Germany
| | - Madeline H. Cooper
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Laura Laprell
- Institute for Synaptic Physiology, ZMNH, University Medical Center Hamburg-Eppendorf, D-20251 Hamburg, Germany
| | - Emily Jie-Ning Yang
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Sander Folkerts
- Department of Chemistry, New York University, New York, NY 10003, USA
| | - Ruiyang Bao
- Department of Chemistry, New York University, New York, NY 10003, USA
| | - Malgorzata Boczkowska
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Nicholas J. Palmer
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Roberto Dominguez
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Thomas G. Oertner
- Institute for Synaptic Physiology, ZMNH, University Medical Center Hamburg-Eppendorf, D-20251 Hamburg, Germany
| | - Liza A. Pon
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - J. Bradley Zuchero
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Dirk H. Trauner
- Department of Chemistry, New York University, New York, NY 10003, USA
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
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2
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Lv Z, Chen L, Chen P, Peng H, Rong Y, Hong W, Zhou Q, Li N, Li B, Paolicelli RC, Zhan Y. Clearance of β-amyloid and synapses by the optogenetic depolarization of microglia is complement selective. Neuron 2024; 112:740-754.e7. [PMID: 38295790 DOI: 10.1016/j.neuron.2023.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Revised: 10/31/2023] [Accepted: 12/07/2023] [Indexed: 02/03/2024]
Abstract
Microglia actively monitor the neighboring brain microenvironments and constantly contact synapses with their unique ramified processes. In neurodegenerative diseases, including Alzheimer's disease (AD), microglia undergo morphological and functional alterations. Whether the direct manipulation of microglia can selectively or concurrently modulate synaptic function and the response to disease-associated factors remains elusive. Here, we employ optogenetic methods to stimulate microglia in vitro and in vivo. Membrane depolarization rapidly changes microglia morphology and leads to enhanced phagocytosis. We found that the optogenetic stimulation of microglia can efficiently promote β-amyloid (Aβ) clearance in the brain parenchyma, but it can also enhance synapse elimination. Importantly, the inhibition of C1q selectively prevents synapse loss induced by microglia depolarization but does not affect Aβ clearance. Our data reveal independent microglia-mediated phagocytosis pathways toward Aβ and synapses. Our results also shed light on a synergistic strategy of depolarizing microglia and inhibiting complement functions for the clearance of Aβ while sparing synapses.
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Affiliation(s)
- Zezhong Lv
- Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lixi Chen
- Guangdong Provincial Key Laboratory of Brain Function and Disease, Neuroscience Program, Zhongshan School of Medicine and the Fifth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China
| | - Ping Chen
- Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Huipai Peng
- Shenzhen Institute of Synthetic Biology, CAS Key Laboratory for Quantitative Engineering Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Yi Rong
- State Key Laboratory of Chemical Oncogenomics, Guangdong Provincial Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen 518055, China
| | - Wei Hong
- Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Qiang Zhou
- State Key Laboratory of Chemical Oncogenomics, Guangdong Provincial Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen 518055, China; Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen 518055, China
| | - Nan Li
- Shenzhen Institute of Synthetic Biology, CAS Key Laboratory for Quantitative Engineering Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Boxing Li
- Guangdong Provincial Key Laboratory of Brain Function and Disease, Neuroscience Program, Zhongshan School of Medicine and the Fifth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China
| | - Rosa C Paolicelli
- Department of Biomedical Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne 1005, Switzerland
| | - Yang Zhan
- Brain Cognition and Brain Disease Institute, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China; Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen 518055, China.
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3
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Zhao S, Umpierre AD, Wu LJ. Tuning neural circuits and behaviors by microglia in the adult brain. Trends Neurosci 2024; 47:181-194. [PMID: 38245380 PMCID: PMC10939815 DOI: 10.1016/j.tins.2023.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 11/04/2023] [Accepted: 12/21/2023] [Indexed: 01/22/2024]
Abstract
Microglia are the primary immune cells of the CNS, contributing to both inflammatory damage and tissue repair in neurological disorder. In addition, emerging evidence highlights the role of homeostatic microglia in regulating neuronal activity, interacting with synapses, tuning neural circuits, and modulating behaviors. Herein, we review how microglia sense and regulate neuronal activity through synaptic interactions, thereby directly engaging with neural networks and behaviors. We discuss current studies utilizing microglial optogenetic and chemogenetic approaches to modulate adult neural circuits. These manipulations of microglia across different CNS regions lead to diverse behavioral consequences. We propose that spatial heterogeneity of microglia-neuron interaction lays the groundwork for understanding diverse functions of microglia in neural circuits and behaviors.
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Affiliation(s)
- Shunyi Zhao
- Department of Neurology, Mayo Clinic, Rochester, MN, USA; Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, USA
| | | | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, MN, USA; Department of Immunology, Mayo Clinic, Rochester, MN, USA; Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA.
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4
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Xie M, Pallegar PN, Parusel S, Nguyen AT, Wu LJ. Regulation of cortical hyperexcitability in amyotrophic lateral sclerosis: focusing on glial mechanisms. Mol Neurodegener 2023; 18:75. [PMID: 37858176 PMCID: PMC10585818 DOI: 10.1186/s13024-023-00665-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Accepted: 10/05/2023] [Indexed: 10/21/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder characterized by the loss of both upper and lower motor neurons, resulting in muscle weakness, atrophy, paralysis, and eventually death. Motor cortical hyperexcitability is a common phenomenon observed at the presymptomatic stage of ALS. Both cell-autonomous (the intrinsic properties of motor neurons) and non-cell-autonomous mechanisms (cells other than motor neurons) are believed to contribute to cortical hyperexcitability. Decoding the pathological relevance of these dynamic changes in motor neurons and glial cells has remained a major challenge. This review summarizes the evidence of cortical hyperexcitability from both clinical and preclinical research, as well as the underlying mechanisms. We discuss the potential role of glial cells, particularly microglia, in regulating abnormal neuronal activity during the disease progression. Identifying early changes such as neuronal hyperexcitability in the motor system may provide new insights for earlier diagnosis of ALS and reveal novel targets to halt the disease progression.
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Affiliation(s)
- Manling Xie
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Praveen N Pallegar
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
- Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, USA
| | - Sebastian Parusel
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Aivi T Nguyen
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA.
- Department of Immunology, Mayo Clinic, Rochester, MN, USA.
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5
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Vepřek NA, Cooper MH, Laprell L, Yang EJN, Folkerts S, Bao R, Oertner TG, Pon LA, Zuchero JB, Trauner DH. Optical Control of G-Actin with a Photoswitchable Latrunculin. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.17.549222. [PMID: 37502978 PMCID: PMC10370057 DOI: 10.1101/2023.07.17.549222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Actin is one of the most abundant proteins in eukaryotic cells and a key component of the cytoskeleton. A range of small molecules have emerged that interfere with actin dynamics by either binding to polymeric F-actin or monomeric G-actin to stabilize or destabilize filaments or prevent their formation and growth, respectively. Amongst these, the latrunculins, which bind to G-actin and affect polymerization, are widely used as tools to investigate actin-dependent cellular processes. Here, we report a photoswitchable version of latrunculin, termed opto-latrunculin (OptoLat), which binds to G-actin in a light-dependent fashion and affords optical control over actin polymerization. OptoLat can be activated with 390 - 490 nm pulsed light and rapidly relaxes to the inactive form in the dark. Light activated OptoLat induced depolymerization of F-actin networks in oligodendrocytes and budding yeast, as shown by fluorescence microscopy. Subcellular control of actin dynamics in human cancer cell lines was demonstrated by live cell imaging. Light-activated OptoLat also reduced microglia surveillance in organotypic mouse brain slices while ramification was not affected. Incubation in the dark did not alter the structural and functional integrity of microglia. Together, our data demonstrate that OptoLat is a useful tool for the elucidation of G-actin dependent dynamic processes in cells and tissues.
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Affiliation(s)
- Nynke A Vepřek
- Department of Chemistry, New York University, New York, NY 10003, USA
- Department of Chemistry, Ludwig Maximilian University, D-80539 Munich, Germany
| | - Madeline H Cooper
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Laura Laprell
- Institute for Synaptic Physiology, ZMNH, University Medical Center Hamburg-Eppendorf, D-20251 Hamburg, Germany
| | - Emily Jie-Ning Yang
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Sander Folkerts
- Department of Chemistry, New York University, New York, NY 10003, USA
| | - Ruiyang Bao
- Department of Chemistry, New York University, New York, NY 10003, USA
| | - Thomas G Oertner
- Institute for Synaptic Physiology, ZMNH, University Medical Center Hamburg-Eppendorf, D-20251 Hamburg, Germany
| | - Liza A Pon
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - J Bradley Zuchero
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Dirk H Trauner
- Department of Chemistry, New York University, New York, NY 10003, USA
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
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6
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Whitelaw BS, Stoessel MB, Majewska AK. Movers and shakers: Microglial dynamics and modulation of neural networks. Glia 2023; 71:1575-1591. [PMID: 36533844 PMCID: PMC10729610 DOI: 10.1002/glia.24323] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 12/02/2022] [Accepted: 12/06/2022] [Indexed: 12/24/2022]
Abstract
Microglia are multifaceted cells that act as immune sentinels, with important roles in pathological events, but also as integral contributors to the normal development and function of neural circuits. In the last decade, our understanding of the contributions these cells make to synaptic health and dysfunction has expanded at a dizzying pace. Here we review the known mechanisms that govern the dynamics of microglia allowing these motile cells to interact with synapses, and recruit microglia to specific sites on neurons. We then review the molecular signals that may underlie the function of microglia in synaptic remodeling. The emerging picture from the literature suggests that microglia are highly sensitive cells, reacting to neuronal signals with dynamic and specific actions tuned to the need of specific synapses and networks.
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Affiliation(s)
- Brendan Steven Whitelaw
- Department of Neuroscience, Center for Visual Science, University of Rochester, Rochester, New York, USA
| | - Mark Blohm Stoessel
- Department of Neuroscience, Center for Visual Science, University of Rochester, Rochester, New York, USA
| | - Ania Katarzyna Majewska
- Department of Neuroscience, Center for Visual Science, University of Rochester, Rochester, New York, USA
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7
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Calvin-Cejudo L, Martin F, Mendez LR, Coya R, Castañeda-Sampedro A, Gomez-Diaz C, Alcorta E. Neuron-glia interaction at the receptor level affects olfactory perception in adult Drosophila. iScience 2022; 26:105837. [PMID: 36624835 PMCID: PMC9823236 DOI: 10.1016/j.isci.2022.105837] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 11/17/2022] [Accepted: 12/16/2022] [Indexed: 12/23/2022] Open
Abstract
Some types of glia play an active role in neuronal signaling by modifying their activity although little is known about their role in sensory information signaling at the receptor level. In this research, we report a functional role for the glia that surround the soma of the olfactory receptor neurons (OSNs) in adult Drosophila. Specific genetic modifications have been targeted to this cell type to obtain live individuals who are tested for olfactory preference and display changes both increasing and reducing sensitivity. A closer look at the antenna by Ca2+ imaging shows that odor activates the OSNs, which subsequently produce an opposite and smaller effect in the glia that partially counterbalances neuronal activation. Therefore, these glia may play a dual role in preventing excessive activation of the OSNs at high odorant concentrations and tuning the chemosensory window for the individual according to the network structure in the receptor organ.
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Affiliation(s)
- Laura Calvin-Cejudo
- Group of Neurobiology of the Sensory Systems (NEUROSEN), Department of Functional Biology, Faculty of Medicine, University of Oviedo, 33006 Oviedo, Spain
| | - Fernando Martin
- Group of Neurobiology of the Sensory Systems (NEUROSEN), Department of Functional Biology, Faculty of Medicine, University of Oviedo, 33006 Oviedo, Spain
| | - Luis R. Mendez
- Group of Neurobiology of the Sensory Systems (NEUROSEN), Department of Functional Biology, Faculty of Medicine, University of Oviedo, 33006 Oviedo, Spain
| | - Ruth Coya
- Group of Neurobiology of the Sensory Systems (NEUROSEN), Department of Functional Biology, Faculty of Medicine, University of Oviedo, 33006 Oviedo, Spain
| | - Ana Castañeda-Sampedro
- Group of Neurobiology of the Sensory Systems (NEUROSEN), Department of Functional Biology, Faculty of Medicine, University of Oviedo, 33006 Oviedo, Spain
| | - Carolina Gomez-Diaz
- Group of Neurobiology of the Sensory Systems (NEUROSEN), Department of Functional Biology, Faculty of Medicine, University of Oviedo, 33006 Oviedo, Spain
| | - Esther Alcorta
- Group of Neurobiology of the Sensory Systems (NEUROSEN), Department of Functional Biology, Faculty of Medicine, University of Oviedo, 33006 Oviedo, Spain
- Corresponding author
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Han X, Cheng X, Xu J, Liu Y, Zhou J, Jiang L, Gu X, Xia T. Activation of TREM2 attenuates neuroinflammation via PI3K/Akt signaling pathway to improve postoperative cognitive dysfunction in mice. Neuropharmacology 2022; 219:109231. [PMID: 36041498 DOI: 10.1016/j.neuropharm.2022.109231] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 08/14/2022] [Accepted: 08/17/2022] [Indexed: 11/30/2022]
Abstract
Postoperative cognitive dysfunction (POCD) is a common postoperative complication involving the central nervous system, but the underlying mechanism is not well understood. Neuroinflammation secondary to surgery and anesthesia is strongly correlated with POCD. A key aspect of neuroinflammation is microglia activation. Triggering receptor expressed on myeloid cells (TREM)2, which is highly expressed in microglia, is an innate immune receptor that modulates microglia function. In this study we investigated the role of TREM2 in cognitive impairment and microglia-mediated neuroinflammation using a mouse model of POCD and in vitro systems. We found that hippocampus-dependent learning and memory were impaired in POCD mice, which was accompanied by activation of microglia and downregulation of TREM2. Pretreatment with the TREM2 agonist heat shock protein (HSP)60 inhibited surgery-induced microglia activation and alleviated postoperative cognitive impairment. In BV2 microglial cells, the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 significantly reversed the attenuation of TREM2 activation on lipopolysaccharide (LPS)-induced neuroinflammation and abrogated the protective effect of activated TREM2 against LPS-induced neuronal injury in a microglia/neuron coculture system. Accordingly, the beneficial effects of TREM2 activation on cognitive function were reversed by preoperative administration of LY294002 in the POCD mouse model. These results demonstrate that TREM2 is involved in the regulation of the inflammatory response mediated by microglia and cognitive impairment following surgery. Activation of TREM2 can attenuate neuroinflammation by modulating PI3K/protein kinase B (Akt) signaling, thereby alleviating postoperative learning and memory deficits.
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Affiliation(s)
- Xue Han
- Department of Anesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, 210008, China; Medical School, Nanjing University, Nanjing, 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, China
| | - Xiaolei Cheng
- Department of Anesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, 210008, China
| | - Jiyan Xu
- Department of Anesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, 210008, China; Medical School, Nanjing University, Nanjing, 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, China
| | - Yujia Liu
- Department of Anesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, 210008, China; Medical School, Nanjing University, Nanjing, 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, China
| | - Jiawen Zhou
- Department of Anesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, 210008, China; Medical School, Nanjing University, Nanjing, 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, China
| | - Linhao Jiang
- Department of Anesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, 210008, China; Medical School, Nanjing University, Nanjing, 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, China
| | - Xiaoping Gu
- Department of Anesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, 210008, China.
| | - Tianjiao Xia
- Department of Anesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, 210008, China; Medical School, Nanjing University, Nanjing, 210093, China; Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, China; State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, China.
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Zheng J, Murugan M, Wang L, Wu LJ. Microglial voltage-gated proton channel Hv1 in spinal cord injury. Neural Regen Res 2022; 17:1183-1189. [PMID: 34782552 PMCID: PMC8643068 DOI: 10.4103/1673-5374.327325] [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: 11/12/2020] [Revised: 12/12/2020] [Accepted: 05/20/2021] [Indexed: 11/23/2022] Open
Abstract
After spinal cord injury, microglia as the first responders to the lesion display both beneficial and detrimental characteristics. Activated microglia phagocyte and eliminate cell debris, release cytokines to recruit peripheral immune cells to the injury site. Excessively activated microglia can aggravate the secondary damage by producing extravagant reactive oxygen species and pro-inflammatory cytokines. Recent studies demonstrated that the voltage-gated proton channel Hv1 is selectively expressed in microglia and regulates microglial activation upon injury. In mouse models of spinal cord injury, Hv1 deficiency ameliorates microglia activation, resulting in alleviated production of reactive oxygen species and pro-inflammatory cytokines. The reduced secondary damage subsequently decreases neuronal loss and correlates with improved locomotor recovery. This review provides a brief historical perspective of advances in investigating voltage-gated proton channel Hv1 and home in on microglial Hv1. We discuss recent studies on the roles of Hv1 activation in pathophysiological activities of microglia, such as production of NOX-dependent reactive oxygen species, microglia polarization, and tissue acidosis, particularly in the context of spinal cord injury. Further, we highlight the rationale for targeting Hv1 for the treatment of spinal cord injury and related disorders.
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Affiliation(s)
- Jiaying Zheng
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | - Madhuvika Murugan
- Department of Neurosurgery, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, USA
| | - Lingxiao Wang
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA
- Department of Immunology, Mayo Clinic, Rochester, MN, USA
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10
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Role of K + and Ca 2+-Permeable Channels in Osteoblast Functions. Int J Mol Sci 2021; 22:ijms221910459. [PMID: 34638799 PMCID: PMC8509041 DOI: 10.3390/ijms221910459] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 09/23/2021] [Accepted: 09/24/2021] [Indexed: 12/20/2022] Open
Abstract
Bone-forming cells or osteoblasts play an important role in bone modeling and remodeling processes. Osteoblast differentiation or osteoblastogenesis is orchestrated by multiple intracellular signaling pathways (e.g., bone morphogenetic proteins (BMP) and Wnt signaling pathways) and is modulated by the extracellular environment (e.g., parathyroid hormone (PTH), vitamin D, transforming growth factor β (TGF-β), and integrins). The regulation of bone homeostasis depends on the proper differentiation and function of osteoblast lineage cells from osteogenic precursors to osteocytes. Intracellular Ca2+ signaling relies on the control of numerous processes in osteoblast lineage cells, including cell growth, differentiation, migration, and gene expression. In addition, hyperpolarization via the activation of K+ channels indirectly promotes Ca2+ signaling in osteoblast lineage cells. An improved understanding of the fundamental physiological and pathophysiological processes in bone homeostasis requires detailed investigations of osteoblast lineage cells. This review summarizes the current knowledge on the functional impacts of K+ channels and Ca2+-permeable channels, which critically regulate Ca2+ signaling in osteoblast lineage cells to maintain bone homeostasis.
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Choi S, Guo L, Cordeiro MF. Retinal and Brain Microglia in Multiple Sclerosis and Neurodegeneration. Cells 2021; 10:cells10061507. [PMID: 34203793 PMCID: PMC8232741 DOI: 10.3390/cells10061507] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 05/28/2021] [Accepted: 06/11/2021] [Indexed: 12/24/2022] Open
Abstract
Microglia are the resident immune cells of the central nervous system (CNS), including the retina. Similar to brain microglia, retinal microglia are responsible for retinal surveillance, rapidly responding to changes in the environment by altering morphotype and function. Microglia become activated in inflammatory responses in neurodegenerative diseases, including multiple sclerosis (MS). When activated by stress stimuli, retinal microglia change their morphology and activity, with either beneficial or harmful consequences. In this review, we describe characteristics of CNS microglia, including those in the retina, with a focus on their morphology, activation states and function in health, ageing, MS and other neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, glaucoma and retinitis pigmentosa, to highlight their activity in disease. We also discuss contradictory findings in the literature and the potential ways of reducing inconsistencies in future by using standardised methodology, e.g., automated algorithms, to enable a more comprehensive understanding of this exciting area of research.
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Affiliation(s)
- Soyoung Choi
- UCL Institute of Ophthalmology, London EC1V 9EL, UK; (S.C.); (L.G.)
| | - Li Guo
- UCL Institute of Ophthalmology, London EC1V 9EL, UK; (S.C.); (L.G.)
| | - Maria Francesca Cordeiro
- UCL Institute of Ophthalmology, London EC1V 9EL, UK; (S.C.); (L.G.)
- ICORG, Imperial College London, London NW1 5QH, UK
- Correspondence:
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