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Claeys W, Geerts A, Van Hoecke L, Van Steenkiste C, Vandenbroucke RE. Role of astrocytes and microglia in hepatic encephalopathy associated with advanced chronic liver disease: lessons from animal studies. Neural Regen Res 2025; 20:3461-3475. [PMID: 39688562 PMCID: PMC11974659 DOI: 10.4103/nrr.nrr-d-24-00600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2024] [Revised: 08/05/2024] [Accepted: 11/20/2024] [Indexed: 12/18/2024] Open
Abstract
Hepatic encephalopathy, defined as neuropsychiatric dysfunction secondary to liver disease, is a frequent decompensating event in cirrhosis. Its clinical impact is highlighted by a notable increase in patient mortality rates and a concomitant reduction in overall quality of life. Systemically, liver disease, liver function failure, portosystemic shunting, and associated multi-organ dysfunction result in the increase of disease-causing neurotoxins in the circulation, which impairs cerebral homeostasis. Key circulating neurotoxins are ammonia and inflammatory mediators. In the brain, pathophysiology is less well understood, but is thought to be driven by glial cell dysfunction. Astrocytes are the only brain resident cells that have ammonia-metabolizing machinery and are therefore putatively most susceptible to ammonia elevation. Based on a large body of mostly in vitro evidence, ammonia-induced cellular and molecular disturbances include astrocyte swelling and oxidative stress. Microglia, the brain resident macrophages, have been linked to the translation of systemic inflammation to the brain microenvironment. Recent evidence from animal studies has provided novel insights into old and new downstream effects of astrocyte and microglial dysfunction such as toxin clearance disruption and myeloid cell attraction to the central nervous system parenchyma. Furthermore, state of the art research increasingly implicates neuronal dysfunction and possibly even irreversible neuronal cell death. Cell-type specific investigation in animal models highlights the need for critical revision of the contribution of astrocytes and microglia to well-established and novel cellular and molecular alterations in hepatic encephalopathy. In this review, we therefore give a current and comprehensive overview of causes, features, and consequences of astrocyte and microglial dysfunction in hepatic encephalopathy, including areas of interest for future investigation.
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Affiliation(s)
- Wouter Claeys
- Department of Internal Medicine and Paediatrics, Hepatology Research Unit, Ghent University, Ghent, Belgium
- Liver Research Center Ghent, Ghent University, Ghent University Hospital, Ghent, Belgium
- Barriers in Inflammation, VIB-UGent Center for Inflammation Research, VIB, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Anja Geerts
- Department of Internal Medicine and Paediatrics, Hepatology Research Unit, Ghent University, Ghent, Belgium
- Liver Research Center Ghent, Ghent University, Ghent University Hospital, Ghent, Belgium
- Department of Gastroenterology and Hepatology, Ghent University Hospital, Ghent, Belgium
| | - Lien Van Hoecke
- Barriers in Inflammation, VIB-UGent Center for Inflammation Research, VIB, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Christophe Van Steenkiste
- Department of Gastroenterology and Hepatology, Antwerp University, Antwerp, Belgium
- Department of Gastroenterology and Hepatology, Maria Middelares Hospital, Ghent, Belgium
| | - Roosmarijn E. Vandenbroucke
- Barriers in Inflammation, VIB-UGent Center for Inflammation Research, VIB, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
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2
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He Q, Wang Z, Wang Y, Zhu M, Liang Z, Zhang K, Xu Y, Chen G. Characteristic changes in astrocyte properties during astrocyte-to-neuron conversion induced by NeuroD1/Ascl1/Dlx2. Neural Regen Res 2025; 20:1801-1815. [PMID: 39104117 PMCID: PMC11688565 DOI: 10.4103/nrr.nrr-d-23-01897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 02/04/2024] [Accepted: 03/25/2024] [Indexed: 08/07/2024] Open
Abstract
JOURNAL/nrgr/04.03/01300535-202506000-00030/figure1/v/2024-08-05T133530Z/r/image-tiff Direct in vivo conversion of astrocytes into functional new neurons induced by neural transcription factors has been recognized as a potential new therapeutic intervention for neural injury and degenerative disorders. However, a few recent studies have claimed that neural transcription factors cannot convert astrocytes into neurons, attributing the converted neurons to pre-existing neurons mis-expressing transgenes. In this study, we overexpressed three distinct neural transcription factors--NeuroD1, Ascl1, and Dlx2--in reactive astrocytes in mouse cortices subjected to stab injury, resulting in a series of significant changes in astrocyte properties. Initially, the three neural transcription factors were exclusively expressed in the nuclei of astrocytes. Over time, however, these astrocytes gradually adopted neuronal morphology, and the neural transcription factors was gradually observed in the nuclei of neuron-like cells instead of astrocytes. Furthermore, we noted that transcription factor-infected astrocytes showed a progressive decrease in the expression of astrocytic markers AQP4 (astrocyte endfeet signal), CX43 (gap junction signal), and S100β. Importantly, none of these changes could be attributed to transgene leakage into pre-existing neurons. Therefore, our findings suggest that neural transcription factors such as NeuroD1, Ascl1, and Dlx2 can effectively convert reactive astrocytes into neurons in the adult mammalian brain.
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Affiliation(s)
- Qing He
- GHM Institute of CNS Regeneration, Jinan University, Guangzhou, Guangdong Province, China
| | - Zhen Wang
- GHM Institute of CNS Regeneration, Jinan University, Guangzhou, Guangdong Province, China
| | - Yuchen Wang
- GHM Institute of CNS Regeneration, Jinan University, Guangzhou, Guangdong Province, China
| | - Mengjie Zhu
- GHM Institute of CNS Regeneration, Jinan University, Guangzhou, Guangdong Province, China
| | - Zhile Liang
- GHM Institute of CNS Regeneration, Jinan University, Guangzhou, Guangdong Province, China
| | - Kanghong Zhang
- GHM Institute of CNS Regeneration, Jinan University, Guangzhou, Guangdong Province, China
| | - Yuge Xu
- GHM Institute of CNS Regeneration, Jinan University, Guangzhou, Guangdong Province, China
| | - Gong Chen
- GHM Institute of CNS Regeneration, Jinan University, Guangzhou, Guangdong Province, China
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3
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Song Q, Wu X, Yang J, Li S, Duan J. Glial connexins in glaucoma. Front Neurosci 2025; 19:1560344. [PMID: 40270762 PMCID: PMC12014763 DOI: 10.3389/fnins.2025.1560344] [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: 01/14/2025] [Accepted: 03/24/2025] [Indexed: 04/25/2025] Open
Abstract
Glial cells play a crucial role in maintaining central nervous system (CNS) homeostasis and facilitating the repair of neural tissue following injury. The regulation of neuroglia may serve as a safe and effective strategy for modulating neuroinflammatory responses and restoring glial homeostasis and defense functions. Given that the glial network is composed of connexin (CX) proteins, its neuroprotective role is extensive. Therefore, connexins should be considered as functional "bridges" within this network. This review examines evidence for the active involvement of glial networks in neuroinflammation under both physiological and pathological conditions and summarizes the role of CXs in glaucoma. Finally, potential therapeutic strategies for glaucoma are explored.
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Affiliation(s)
- Qiuyi Song
- Chengdu University of TCM, Chengdu, China
- Eye College of Chengdu University of TCM, Chengdu, China
| | - Xi Wu
- Chengdu University of TCM, Chengdu, China
- Eye College of Chengdu University of TCM, Chengdu, China
| | - Jiawei Yang
- Chengdu University of TCM, Chengdu, China
- Eye College of Chengdu University of TCM, Chengdu, China
- Key Laboratory of Sichuan Province Ophthalmopathy Prevention & Cure and Visual Function Protection with TCM Laboratory, Chengdu, China
| | - Siqi Li
- Chengdu University of TCM, Chengdu, China
| | - Junguo Duan
- Chengdu University of TCM, Chengdu, China
- Eye College of Chengdu University of TCM, Chengdu, China
- Key Laboratory of Sichuan Province Ophthalmopathy Prevention & Cure and Visual Function Protection with TCM Laboratory, Chengdu, China
- Ineye Hospital of Chengdu University of TCM, Chengdu, China
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4
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Liu Y, Cai X, Shi B, Mo Y, Zhang J, Luo W, Yu B, Li X. Mechanisms and Therapeutic Prospects of Microglia-Astrocyte Interactions in Neuropathic Pain Following Spinal Cord Injury. Mol Neurobiol 2025; 62:4654-4676. [PMID: 39470872 DOI: 10.1007/s12035-024-04562-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2024] [Accepted: 10/16/2024] [Indexed: 11/01/2024]
Abstract
Neuropathic pain is a prevalent and debilitating condition experienced by the majority of individuals with spinal cord injury (SCI). The complex pathophysiology of neuropathic pain, involving continuous activation of microglia and astrocytes, reactive gliosis, and altered neuronal plasticity, poses significant challenges for effective treatment. This review focuses on the pivotal roles of microglia and astrocytes, the two major glial cell types in the central nervous system, in the development and maintenance of neuropathic pain after SCI. We highlight the extensive bidirectional interactions between these cells, mediated by the release of inflammatory mediators, neurotransmitters, and neurotrophic factors, which contribute to the amplification of pain signaling. Understanding the microglia-astrocyte crosstalk and its impact on neuronal function is crucial for developing novel therapeutic strategies targeting neuropathic pain. In addition, this review discusses the fundamental biology, post-injury pain roles, and therapeutic prospects of microglia and astrocytes in neuropathic pain after SCI and elucidates the specific signaling pathways involved. We also speculated that the extracellular matrix (ECM) can affect the glial cells as well. Furthermore, we also mentioned potential targeted therapies, challenges, and progress in clinical trials, as well as new biomarkers and therapeutic targets. Finally, other relevant cell interactions in neuropathic pain and the role of glial cells in other neuropathic pain conditions have been discussed. This review serves as a comprehensive resource for further investigations into the microglia-astrocyte interaction and the detailed mechanisms of neuropathic pain after SCI, with the aim of improving therapeutic efficacy.
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Affiliation(s)
- Yinuo Liu
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, Jiangxi, China
- The Clinical Medical College, Nanchang University, Nanchang, 330006, Jiangxi, China
| | - Xintong Cai
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, Jiangxi, China
- The Clinical Medical College, Nanchang University, Nanchang, 330006, Jiangxi, China
| | - Bowen Shi
- The Clinical Medical College, Nanchang University, Nanchang, 330006, Jiangxi, China
| | - Yajie Mo
- The Clinical Medical College, Nanchang University, Nanchang, 330006, Jiangxi, China
| | - Jianmin Zhang
- The Clinical Medical College, Nanchang University, Nanchang, 330006, Jiangxi, China
| | - Wenting Luo
- The Clinical Medical College, Nanchang University, Nanchang, 330006, Jiangxi, China
| | - Bodong Yu
- The Clinical Medical College, Nanchang University, Nanchang, 330006, Jiangxi, China
| | - Xi Li
- Department of Anesthesiology, The Second Affiliated Hospital of Nanchang University, Nanchang, 330006, Jiangxi, China.
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5
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Huang Q, Lee HH, Volpe B, Zhang Q, Xue C, Liu BC, Abuhasan YR, Li L, Yang JS, Egholm J, Gutierrez-Vazquez C, Li A, Lee A, Tang S, Wong CW, Liu T, Huang Y, Ramos RL, Stout RF, El Ouaamari A, Quintana FJ, Lowell BB, Kahn CR, Pothos EN, Cai W. Deletion of murine astrocytic vesicular nucleotide transporter increases anxiety and depressive-like behavior and attenuates motivation for reward. Mol Psychiatry 2025; 30:506-520. [PMID: 39122778 PMCID: PMC11750621 DOI: 10.1038/s41380-024-02692-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Revised: 07/17/2024] [Accepted: 08/02/2024] [Indexed: 08/12/2024]
Abstract
Astrocytes are multi-functional glial cells in the central nervous system that play critical roles in modulation of metabolism, extracellular ion and neurotransmitter levels, and synaptic plasticity. Astrocyte-derived signaling molecules mediate many of these modulatory functions of astrocytes, including vesicular release of ATP. In the present study, we used a unique genetic mouse model to investigate the functional significance of astrocytic exocytosis of ATP. Using primary cultured astrocytes, we show that loss of vesicular nucleotide transporter (Vnut), a primary transporter responsible for loading cytosolic ATP into the secretory vesicles, dramatically reduces ATP loading into secretory lysosomes and ATP release, without any change in the molecular machinery of exocytosis or total intracellular ATP content. Deletion of astrocytic Vnut in adult mice leads to increased anxiety, depressive-like behaviors, and decreased motivation for reward, especially in females, without significant impact on food intake, systemic glucose metabolism, cognition, or sociability. These behavioral alterations are associated with significant decreases in the basal extracellular dopamine levels in the nucleus accumbens. Likewise, ex vivo brain slices from these mice show a strong trend toward a reduction in evoked dopamine release in the nucleus accumbens. Mechanistically, the reduced dopamine signaling we observed is likely due to an increased expression of monoamine oxidases. Together, these data demonstrate a key modulatory role of astrocytic exocytosis of ATP in anxiety, depressive-like behavior, and motivation for reward, by regulating the mesolimbic dopamine circuitry.
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Affiliation(s)
- Qian Huang
- Department of Molecular and Cellular Biochemistry, the Barnstable Brown Diabetes and Obesity Center, University of Kentucky College of Medicine, Lexington, KY, USA
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA
| | - Hiu Ham Lee
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA
| | - Bryan Volpe
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA
| | - Qingchen Zhang
- Program in Pharmacology and Experimental Therapeutics and Pharmacology and Drug Development, Graduate School of Biomedical Sciences and Department of Immunology, Tufts University School of Medicine, Boston, MA, USA
| | - Chang Xue
- Program in Pharmacology and Experimental Therapeutics and Pharmacology and Drug Development, Graduate School of Biomedical Sciences and Department of Immunology, Tufts University School of Medicine, Boston, MA, USA
| | - Brian C Liu
- Section of Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | - Yahia R Abuhasan
- Program in Pharmacology and Experimental Therapeutics and Pharmacology and Drug Development, Graduate School of Biomedical Sciences and Department of Immunology, Tufts University School of Medicine, Boston, MA, USA
| | - Lingyun Li
- Program in Pharmacology and Experimental Therapeutics and Pharmacology and Drug Development, Graduate School of Biomedical Sciences and Department of Immunology, Tufts University School of Medicine, Boston, MA, USA
| | - Jeremy S Yang
- Program in Pharmacology and Experimental Therapeutics and Pharmacology and Drug Development, Graduate School of Biomedical Sciences and Department of Immunology, Tufts University School of Medicine, Boston, MA, USA
| | - Julie Egholm
- Program in Pharmacology and Experimental Therapeutics and Pharmacology and Drug Development, Graduate School of Biomedical Sciences and Department of Immunology, Tufts University School of Medicine, Boston, MA, USA
| | - Cristina Gutierrez-Vazquez
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Allen Li
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA
| | - Alyssa Lee
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA
| | - Sharon Tang
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA
| | - Chun Wa Wong
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA
| | - Tiemin Liu
- Key Laboratory of Genetic Engineering, Department of Endocrinology and Metabolism, School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai, PR China
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Yuan Huang
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA
| | - Raddy L Ramos
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA
| | - Randy F Stout
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA
| | | | - Francisco J Quintana
- Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Bradford B Lowell
- Department of Medicine, Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - C Ronald Kahn
- Section of Integrative Physiology and Metabolism, Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA
| | - Emmanuel N Pothos
- Program in Pharmacology and Experimental Therapeutics and Pharmacology and Drug Development, Graduate School of Biomedical Sciences and Department of Immunology, Tufts University School of Medicine, Boston, MA, USA
| | - Weikang Cai
- Department of Molecular and Cellular Biochemistry, the Barnstable Brown Diabetes and Obesity Center, University of Kentucky College of Medicine, Lexington, KY, USA.
- Department of Biomedical Sciences, New York Institute of Technology College of Osteopathic Medicine, Old Westbury, NY, USA.
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6
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Li M, Nie H, He Q, Zhang Z, Yu S, Wang T, Fu B. Astrocytic Gap Junctions protein Cx43/Cx30 modulate EAAT1 and glutamate to mediate cerebral ischemia-reperfusion injury. Brain Res 2025; 1847:149306. [PMID: 39491663 DOI: 10.1016/j.brainres.2024.149306] [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: 08/06/2024] [Revised: 10/16/2024] [Accepted: 10/30/2024] [Indexed: 11/05/2024]
Abstract
The gap connexins of astrocytes play a crucial role in facilitating neuronal coordination and maintaining the homeostasis of the central nervous system. Cx30/Cx43 are the main proteins constituting these gap junctions, and the glutamate transporter EAAT1 associates with nerve injury. However, the role and mechanism underlying the changes of astrocytic connexins and EAAT1 during cerebral ischemia-reperfusion injury remain unclear. In this study, we investigated the expressions of Cx30, Cx43, and EAAT1 in OGD/R-treated astrocytes and in a MCAO/R animal model using gap junction inhibitors and siRNAs targeting Cx43 and Cx30. The differences of cell viability, malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), reactive oxygen species (ROS) and glutamate in cells and tissues were detected. Our results indicate that OGD/R exposure leads to the decline of astrocyte activity, which, in turn, adversely affects neuronal health. Ischemia-reperfusion induced increasing Cx43 and EAAT1 expression and decreasing Cx30 expression in astrocytes and animal brain tissue. Moreover, ischemia-reperfusion resulted in heightened MDA and ROS levels and reduced CAT and SOD activities in both astrocytes and the surrounding brain tissue. The release of glutamate from astrocytes and its concentration in animal brain tissue significantly increased following ischemia-reperfusion. Inhibition Cx43 expression through Gap26 or siRNA effectively mitigated the increase in EAAT1 and glutamate levels, as well as the oxidative stress changes induced by ischemia-reperfusion. Therefore, Brain astrocytes may mediate the effects of cerebral ischemia-reperfusion injury by influencing glutamate transporters and glutamate dynamics in response to oxidative stress through Cx30/Cx43.
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Affiliation(s)
- Min Li
- Rehabilitation Medicine Department of the Second People's Hospital Lianyungang, PR China
| | - Hongxia Nie
- Neurology Department of the Second People's Hospital Lianyungang, PR China
| | - Qianqian He
- Neurology Department of the Second People's Hospital Lianyungang, PR China
| | - Zhaoting Zhang
- Neurology Department of the Second People's Hospital Lianyungang, PR China
| | - Shanhua Yu
- Neurology Department of the Second People's Hospital Lianyungang, PR China
| | - Tiantian Wang
- Rehabilitation Medicine Department of the Second People's Hospital Lianyungang, PR China
| | - Bing Fu
- Neurology Department of the Second People's Hospital Lianyungang, PR China.
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7
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Paunikar S, Tamagnone L. Connexin-43 in Cancer: Above and Beyond Gap Junctions! Cancers (Basel) 2024; 16:4191. [PMID: 39766090 PMCID: PMC11674308 DOI: 10.3390/cancers16244191] [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: 11/07/2024] [Revised: 12/08/2024] [Accepted: 12/10/2024] [Indexed: 01/11/2025] Open
Abstract
Connexin-43 (Cx43) is the most characterized gap junction protein, primarily involved in the Gap Junctional Intercellular Communication (GJIC) between adjacent cells to facilitate molecule exchange and the formation of a signaling network. It is increasingly evident that the importance of Cx43 is not only limited to its GJIC function, but rather includes its role in connecting the intracellular and extracellular environment by forming membrane hemichannels, as well as its intracellular signaling function mediated by its C-terminal tail (Cx43-CT). Notably, Cx43 has been implicated in a variety of cancers, with earlier notions suggesting a tumor-suppressor function, whereas new studies shed light on its pro-tumorigenic role. Moreover, apart from GJIC-based activities, the relevance of the non-canonical functions of Cx43 in tumor progression is being actively studied. This review provides an analysis of the current research on the pro-tumorigenic roles of Cx43, with a focus on Cx43-CT interactions and the function of hemichannels in cancer progression. A better understanding of the multifaceted functions of Cx43 in cancer biology could foster its recognition as a pivotal target for the development of innovative therapeutic strategies.
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Affiliation(s)
- Shishir Paunikar
- School of Medicine, Università Cattolica del Sacro Cuore, 00168 Rome, Italy;
| | - Luca Tamagnone
- School of Medicine, Università Cattolica del Sacro Cuore, 00168 Rome, Italy;
- Fondazione Policlinico Universitario “A.Gemelli” IRCCS, 00168 Rome, Italy
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8
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Duarte Y, Quintana-Donoso D, Moraga-Amaro R, Dinamarca I, Lemunao Y, Cárdenas K, Bahamonde T, Barrientos T, Olivares P, Navas C, Carvajal FJ, Santibánez Y, Castro-Lazo R, Paz Meza M, Jorquera R, Gómez GI, Henke M, Alarcón R, Gabriel LA, Schiffmann S, Cerpa W, Retamal MA, Simon F, Linsambarth S, Gonzalez-Nilo F, Stehberg J. The role of astrocytes in depression, its prevention, and treatment by targeting astroglial gliotransmitter release. Proc Natl Acad Sci U S A 2024; 121:e2307953121. [PMID: 39495924 PMCID: PMC11572930 DOI: 10.1073/pnas.2307953121] [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: 06/26/2023] [Accepted: 09/19/2024] [Indexed: 11/06/2024] Open
Abstract
The role of ventral hippocampus (vHipp) astroglial gliotransmission in depression was studied using chronic restraint stress (CRS) and chronic unpredictable mild stress (CUMS) rodent models. CRS increased Cx43 hemichannel activity and extracellular glutamate levels in the vHipp and blocking astroglial Cx43 hemichannel-dependent gliotransmission during CRS prevented the development of depression and glutamate buildup. Moreover, the acute blockade of Cx43 hemichannels induced antidepressant effects in rats previously subjected to CRS or CUMS. This antidepressant effect was prevented by coinjection of glutamate and D-serine. Furthermore, Cx43 hemichannel blockade decreased postsynaptic NMDAR currents in vHipp slices in a glutamate and D-serine-dependent manner. Notably, chronic microinfusion of glutamate and D-serine, L-serine, or the NMDAR agonist NMDA, into the vHipp induced depressive-like symptoms in nonstressed rats. We also identified a small molecule, cacotheline, which blocks Cx43 hemichannels and its systemic administration induced rapid antidepressant effects, preventing stress-induced increases in astroglial Cx43 hemichannel activity and extracellular glutamate in the vHipp, without sedative or locomotor side effects. In conclusion, chronic stress increases Cx43 hemichannel-dependent release of glutamate and D-/L-serine from astrocytes in the vHipp, overactivating postsynaptic NMDARs and triggering depressive-like symptoms. This study highlights the critical role of astroglial gliotransmitter release in chronic stress-induced depression and suggests it can be used as a target for the prevention and treatment of depression.
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Affiliation(s)
- Yorley Duarte
- Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago8370146, Chile
| | - Daisy Quintana-Donoso
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago8370146, Chile
| | - Rodrigo Moraga-Amaro
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago8370146, Chile
| | - Ivanka Dinamarca
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago8370146, Chile
| | - Yordan Lemunao
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago8370146, Chile
| | - Kevin Cárdenas
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago8370146, Chile
| | - Tamara Bahamonde
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago8370146, Chile
| | - Tabita Barrientos
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago8370146, Chile
| | - Pedro Olivares
- Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago8370146, Chile
| | - Camila Navas
- Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago8370146, Chile
| | - Francisco J. Carvajal
- Laboratorio de Función y Patología Neuronal, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Yessenia Santibánez
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago8370146, Chile
| | - Raimundo Castro-Lazo
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago8370146, Chile
| | - María Paz Meza
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago8370146, Chile
| | - Ramon Jorquera
- Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago8370146, Chile
| | - Gonzalo I. Gómez
- Laboratorio de Fisiología Renal y Comunicación Celular, Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago8910060, Chile
| | - Marina Henke
- Fraunhofer Institute for Translational Medicine and Pharmacology (ITMP), Frankfurt am Main60596, Germany
| | - Rodrigo Alarcón
- Programa de Comunicación Celular en Cáncer, Facultad de Medicina, Clínica Alemana, Universidad del Desarrollo, Santiago7610634, Chile
| | - Laureen A. Gabriel
- Fraunhofer Institute for Translational Medicine and Pharmacology (ITMP), Frankfurt am Main60596, Germany
| | - Susanne Schiffmann
- Fraunhofer Institute for Translational Medicine and Pharmacology (ITMP), Frankfurt am Main60596, Germany
| | - Waldo Cerpa
- Laboratorio de Función y Patología Neuronal, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Mauricio A. Retamal
- Programa de Comunicación Celular en Cáncer, Facultad de Medicina, Clínica Alemana, Universidad del Desarrollo, Santiago7610634, Chile
| | - Felipe Simon
- Laboratory of Integrative Physiopathology, Faculty of Life Sciences, Universidad Andres Bello, Santiago8370146, Chile
- Millennium Institute on Immunology and Immunotherapy, Santiago8331150, Chile
| | - Sergio Linsambarth
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago8370146, Chile
| | - Fernando Gonzalez-Nilo
- Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago8370146, Chile
| | - Jimmy Stehberg
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago8370146, Chile
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9
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Bretová K, Svobodová V, Dubový P. Changes in Cx43 and AQP4 Proteins, and the Capture of 3 kDa Dextran in Subpial Astrocytes of the Rat Medial Prefrontal Cortex after Both Sham Surgery and Sciatic Nerve Injury. Int J Mol Sci 2024; 25:10989. [PMID: 39456773 PMCID: PMC11507206 DOI: 10.3390/ijms252010989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2024] [Revised: 10/08/2024] [Accepted: 10/10/2024] [Indexed: 10/28/2024] Open
Abstract
A subpopulation of astrocytes on the brain's surface, known as subpial astrocytes, constitutes the "glia limitans superficialis" (GLS), which is an interface between the brain parenchyma and the cerebrospinal fluid (CSF) in the subpial space. Changes in connexin-43 (Cx43) and aquaporin-4 (AQP4) proteins in subpial astrocytes were examined in the medial prefrontal cortex at postoperative day 1, 3, 7, 14, and 21 after sham operation and sciatic nerve compression (SNC). In addition, we tested the altered uptake of TRITC-conjugated 3 kDa dextran by reactive subpial astrocytes. Cellular immunofluorescence (IF) detection and image analysis were used to examine changes in Cx43 and AQP4 protein levels, as well as TRITC-conjugated 3 kDa dextran, in subpial astrocytes. The intensity of Cx43-IF was significantly increased, but AQP4-IF decreased in subpial astrocytes of sham- and SNC-operated rats during all survival periods compared to naïve controls. Similarly, the uptake of 3 kDa dextran in the GLS was reduced following both sham and SNC operations. The results suggest that both sciatic nerve injury and peripheral tissue injury alone can induce changes in subpial astrocytes related to the spread of their reactivity across the cortical surface mediated by increased amounts of gap junctions. At the same time, water transport and solute uptake were impaired in subpial astrocytes.
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Affiliation(s)
| | | | - Petr Dubový
- Cellular and Molecular Neurobiology Research Group, Department of Anatomy, Faculty of Medicine, Masaryk University, CZ-62500 Brno, Czech Republic; (K.B.)
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10
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Liu P, Zhang X, Zhao N, Dai J, Liang G. Effects of exogenous hydrogen sulfide and honokiol intervention on the proliferation, apoptosis, and calcium signaling pathway of rat enteric glial cells. Biomed Pharmacother 2024; 179:117290. [PMID: 39153433 DOI: 10.1016/j.biopha.2024.117290] [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: 06/01/2024] [Revised: 08/06/2024] [Accepted: 08/08/2024] [Indexed: 08/19/2024] Open
Abstract
Hydrogen sulfide (H2S) is a gaseous signaling molecule that influences digestive and nervous system functions. Enteric glial cells (EGCs) are integral to the enteric nervous system and play a role in regulating gastrointestinal motility. This study explored the dual effects of exogenous H2S on EGCs and the influence of apoptosis-related pathways and ion channels in EGCs. We also administered honokiol for further interventional studies. The results revealed that low-concentration H2S increased the mitochondrial membrane potential (MMP) of EGCs, decreased the whole-cell membrane potential, downregulated BAX and caspase-3, upregulated Bcl2 expression, reduced apoptosis, and promoted cell proliferation. The Ca2+ concentration, Cx43 mRNA, and protein expression were also increased. A high concentration of H2S had the opposite effect. In addition, GFAP mRNA expression was upregulated in the test-low group, downregulated in the test-high group, and upregulated in the test-high + Hon group. Honokiol treatment increased MMP, reduced whole-cell membrane potential, inhibited BAX and caspase-3 expression, increased Bcl2 expression, decreased cell apoptosis, and increased cell proliferation. The Ca2+ concentration, Cx43 mRNA, and protein expression were also upregulated. In conclusion, our study showed that exogenous H2S can bidirectionally regulate EGC proliferation and apoptosis by affecting MMP and cell membrane potential via the Bcl2/BAX/caspase-3 pathway and modulate Cx43-mediated Ca2+ responses in EGCs to regulate colonic motility bidirectionally. Honokiol can ameliorate the damage to EGCs induced by high H2S concentrations through the Bcl2/BAX/caspase-3 pathway and improve colon motility by increasing Cx43 expression and Ca2+ concentration.
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Affiliation(s)
- PengFei Liu
- Department of General Surgery, The First Affiliated Hospital of Dalian Medical University, Dalian 116011, China; Laboratory of Integrative Medicine, The First Affiliated Hospital of Dalian Medical University, Dalian 116000, China
| | - XiaoDan Zhang
- Department of General Surgery, The First Affiliated Hospital of Dalian Medical University, Dalian 116011, China; Laboratory of Integrative Medicine, The First Affiliated Hospital of Dalian Medical University, Dalian 116000, China
| | - Nan Zhao
- Department of General Surgery, The First Affiliated Hospital of Dalian Medical University, Dalian 116011, China; Laboratory of Integrative Medicine, The First Affiliated Hospital of Dalian Medical University, Dalian 116000, China
| | - JiaLing Dai
- Department of General Surgery, The First Affiliated Hospital of Dalian Medical University, Dalian 116011, China; Laboratory of Integrative Medicine, The First Affiliated Hospital of Dalian Medical University, Dalian 116000, China
| | - GuoGang Liang
- Department of General Surgery, The First Affiliated Hospital of Dalian Medical University, Dalian 116011, China; Laboratory of Integrative Medicine, The First Affiliated Hospital of Dalian Medical University, Dalian 116000, China.
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11
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Moțățăianu A, Mănescu IB, Șerban G, Bărcuțean L, Ion V, Bălașa R, Andone S. Exploring the Role of Metabolic Hormones in Amyotrophic Lateral Sclerosis. Int J Mol Sci 2024; 25:5059. [PMID: 38791099 PMCID: PMC11121721 DOI: 10.3390/ijms25105059] [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: 03/26/2024] [Revised: 04/27/2024] [Accepted: 05/04/2024] [Indexed: 05/26/2024] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease characterized by progressive loss of motor neurons. Emerging evidence suggests a potential link between metabolic dysregulation and ALS pathogenesis. This study aimed to investigate the relationship between metabolic hormones and disease progression in ALS patients. A cross-sectional study was conducted involving 44 ALS patients recruited from a tertiary care center. Serum levels of insulin, total amylin, C-peptide, active ghrelin, GIP (gastric inhibitory peptide), GLP-1 active (glucagon-like peptide-1), glucagon, PYY (peptide YY), PP (pancreatic polypeptide), leptin, interleukin-6, MCP-1 (monocyte chemoattractant protein-1), and TNFα (tumor necrosis factor alpha) were measured, and correlations with ALSFRS-R, evolution scores, and biomarkers were analyzed using Spearman correlation coefficients. Subgroup analyses based on ALS subtypes, progression pattern of disease, and disease progression rate patterns were performed. Significant correlations were observed between metabolic hormones and ALS evolution scores. Insulin and amylin exhibited strong correlations with disease progression and clinical functional outcomes, with insulin showing particularly robust associations. Other hormones such as C-peptide, leptin, and GLP-1 also showed correlations with ALS progression and functional status. Subgroup analyses revealed differences in hormone levels based on sex and disease evolution patterns, with male patients showing higher amylin and glucagon levels. ALS patients with slower disease progression exhibited elevated levels of amylin and insulin. Our findings suggest a potential role for metabolic hormones in modulating ALS progression and functional outcomes. Further research is needed to elucidate the underlying mechanisms and explore the therapeutic implications of targeting metabolic pathways in ALS management.
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Affiliation(s)
- Anca Moțățăianu
- Department of Neurology, University of Medicine, Pharmacy, Science and Technology of Târgu Mureș ‘George Emil Palade’, 540142 Târgu Mureș, Romania
- 1st Neurology Clinic, Mures County Clinical Emergency Hospital, 540136 Târgu Mureș, Romania
| | - Ion Bogdan Mănescu
- Department of Laboratory Medicine, University of Medicine, Pharmacy, Science and Technology of Târgu Mureș ‘George Emil Palade’, 540142 Târgu Mureș, Romania
| | - Georgiana Șerban
- Doctoral School, University of Medicine, Pharmacy, Science and Technology of Târgu Mureș ‘George Emil Palade’, 540142 Târgu Mureș, Romania
| | - Laura Bărcuțean
- Department of Neurology, University of Medicine, Pharmacy, Science and Technology of Târgu Mureș ‘George Emil Palade’, 540142 Târgu Mureș, Romania
- 1st Neurology Clinic, Mures County Clinical Emergency Hospital, 540136 Târgu Mureș, Romania
| | - Valentin Ion
- Faculty of Pharmacy, Department of Analytical Chemistry and Drug Analysis, University of Medicine, Pharmacy, Science and Technology of Târgu Mureș ‘George Emil Palade’, 540142 Târgu Mureș, Romania
- Drug Testing Laboratory, University of Medicine, Pharmacy, Science and Technology of Târgu Mureș ‘George Emil Palade’, 540142 Târgu Mureș, Romania
| | - Rodica Bălașa
- Department of Neurology, University of Medicine, Pharmacy, Science and Technology of Târgu Mureș ‘George Emil Palade’, 540142 Târgu Mureș, Romania
- 1st Neurology Clinic, Mures County Clinical Emergency Hospital, 540136 Târgu Mureș, Romania
| | - Sebastian Andone
- Department of Neurology, University of Medicine, Pharmacy, Science and Technology of Târgu Mureș ‘George Emil Palade’, 540142 Târgu Mureș, Romania
- 1st Neurology Clinic, Mures County Clinical Emergency Hospital, 540136 Târgu Mureș, Romania
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12
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Okolo CA, Maran JJ, Watts A, Maripillan J, Harkiolaki M, Martínez AD, Green CR, Mugisho OO. Correlative light and X-ray tomography jointly unveil the critical role of connexin43 channels on inflammation-induced cellular ultrastructural alterations. Heliyon 2024; 10:e27888. [PMID: 38560181 PMCID: PMC10979075 DOI: 10.1016/j.heliyon.2024.e27888] [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: 10/23/2023] [Revised: 03/06/2024] [Accepted: 03/07/2024] [Indexed: 04/04/2024] Open
Abstract
Non-junctional connexin43 (Cx43) plasma membrane hemichannels have been implicated in several inflammatory diseases, particularly playing a role in ATP release that triggers activation of the inflammasome. Therapies targeting the blocking of the hemichannels to prevent the pathological release or uptake of ions and signalling molecules through its pores are of therapeutic interest. To date, there is no close-to-native, high-definition documentation of the impact of Cx43 hemichannel-mediated inflammation on cellular ultrastructure, neither is there a robust account of the ultrastructural changes that occur following treatment with selective Cx43 hemichannel blockers such as Xentry-Gap19 (XG19). A combination of same-sample correlative high-resolution three-dimensional fluorescence microscopy and soft X-ray tomography at cryogenic temperatures, enabled in the identification of novel 3D molecular interactions within the cellular milieu when comparing behaviour in healthy states and during the early onset or late stages under inflammatory conditions. Notably, our findings suggest that XG19 blockage of connexin hemichannels under pro-inflammatory conditions may be crucial in preventing the direct degradation of connexosomes by lysosomes, without affecting connexin protein translation and trafficking. We also delineated fine and gross cellular phenotypes, characteristic of inflammatory insult or road-to-recovery from inflammation, where XG19 could indirectly prevent and reverse inflammatory cytokine-induced mitochondrial swelling and cellular hypertrophy through its action on Cx43 hemichannels. Our findings suggest that XG19 might have prophylactic and therapeutic effects on the inflammatory response, in line with functional studies.
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Affiliation(s)
- Chidinma Adanna Okolo
- Beamline B24, Life Sciences Division, Diamond Light Source, Didcot, Oxfordshire, United Kingdom
| | - Jack Jonathan Maran
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Amy Watts
- Beamline B24, Life Sciences Division, Diamond Light Source, Didcot, Oxfordshire, United Kingdom
| | - Jaime Maripillan
- Centro Interdisciplinario de Neurociencias de Valparaíso (CINV), Universidad de Valparaíso, Valparaíso, Chile
| | - Maria Harkiolaki
- Beamline B24, Life Sciences Division, Diamond Light Source, Didcot, Oxfordshire, United Kingdom
| | - Agustín D. Martínez
- Centro Interdisciplinario de Neurociencias de Valparaíso (CINV), Universidad de Valparaíso, Valparaíso, Chile
| | - Colin R. Green
- Department of Ophthalmology, University of Auckland, New Zealand
| | - Odunayo Omolola Mugisho
- Buchanan Ocular Therapeutics Unit, Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, New Zealand
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13
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Comas M, De Pietri Tonelli D, Berdondini L, Astiz M. Ontogeny of the circadian system: a multiscale process throughout development. Trends Neurosci 2024; 47:36-46. [PMID: 38071123 DOI: 10.1016/j.tins.2023.11.004] [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: 07/23/2023] [Revised: 10/02/2023] [Accepted: 11/12/2023] [Indexed: 01/12/2024]
Abstract
The 24 h (circadian) timing system develops in mammals during the perinatal period. It carries out the essential task of anticipating daily recurring environmental changes to identify the best time of day for each molecular, cellular, and systemic process. Although significant knowledge has been acquired about the organization and function of the adult circadian system, relatively little is known about its ontogeny. During the perinatal period, the circadian system progressively gains functionality under the influence of the early environment. This review explores current evidence on the development of the circadian clock in mammals, highlighting the multilevel complexity of the process and the importance of gaining a better understanding of its underlying biology.
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Affiliation(s)
- Maria Comas
- Circadian Physiology of Neurons and Glia Laboratory, Achucarro Basque Center for Neuroscience, 48940 Leioa, Basque Country, Spain
| | | | - Luca Berdondini
- Microtechnology for Neuroelectronics, Fondazione Istituto Italiano di Tecnologia (IIT), 16163 Genova, Italy
| | - Mariana Astiz
- Circadian Physiology of Neurons and Glia Laboratory, Achucarro Basque Center for Neuroscience, 48940 Leioa, Basque Country, Spain; Ikerbasque - Basque Foundation for Science, Bilbao, Spain; Institute of Neurobiology, University of Lübeck, 23562 Lübeck, Germany.
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14
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Zonta F, Mammano F, Pantano S. Molecular Dynamics Simulation of Permeation Through Connexin Channels. Methods Mol Biol 2024; 2801:45-56. [PMID: 38578412 DOI: 10.1007/978-1-0716-3842-2_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
Molecular dynamics (MD) simulations are a collection of computational tools that can be used to trace intermolecular interactions at the sub-nanometer level. They offer possibilities that are often unavailable to experimental methods, making MD an ideal complementary technique for the understanding a plethora of biological processes. Thanks to significant efforts by many groups of developers around the world, setting up and running MD simulations has become progressively simpler. However, simulating ionic permeation through membrane channels still presents significant caveats.MD simulations of connexin (Cx) hemichannels (HCs) are particularly problematic because HCs create wide pores in the plasma membrane, and the lateral sizes of the extracellular and intracellular regions are quite different. In this chapter, we provide a detailed instruction to perform MD simulations aimed at computationally modeling the permeation of inorganic ions and larger molecules through Cx HCs.
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Affiliation(s)
- Francesco Zonta
- Department of Biological Sciences, School of Science, Xi'an Jiaotong-Liverpool University, Suzhou, China.
| | - Fabio Mammano
- Department of Physics and Astronomy "G. Galilei", University of Padova, Padova, Italy
- Institute of Biochemistry and Cell Biology, Italian National Research Council, Rome, Italy
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15
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Jensen BK. Astrocyte-Neuron Interactions Contributing to Amyotrophic Lateral Sclerosis Progression. ADVANCES IN NEUROBIOLOGY 2024; 39:285-318. [PMID: 39190080 DOI: 10.1007/978-3-031-64839-7_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/28/2024]
Abstract
Amyotrophic lateral sclerosis (ALS) is a complex disease impacting motor neurons of the brain, brainstem, and spinal cord. Disease etiology is quite heterogeneous with over 40 genes causing the disease and a vast ~90% of patients having no prior family history. Astrocytes are major contributors to ALS, particularly through involvement in accelerating disease progression. Through study of genetic forms of disease including SOD1, TDP43, FUS, C9orf72, VCP, TBK1, and more recently patient-derived cells from sporadic individuals, many biological mechanisms have been identified to cause intrinsic or glial-mediated neurotoxicity to motor neurons. Overall, many of the normally supportive and beneficial roles that astrocytes contribute to neuronal health and survival instead switch to become deleterious and neurotoxic. While the exact pathways may differ based on disease-origin, altered astrocyte-neuron communication is a common feature of ALS. Within this chapter, distinct genetic forms are examined in detail, along with what is known from sporadic patient-derived cells. Overall, this chapter highlights the interplay between astrocytes and neurons in this complex disease and describes the key features underlying: astrocyte-mediated motor neuron toxicity, excitotoxicity, oxidative/nitrosative stress, protein dyshomeostasis, metabolic imbalance, inflammation, trophic factor withdrawal, blood-brain/blood-spinal cord barrier involvement, disease spreading, and the extracellular matrix/cell adhesion/TGF-β signaling pathways.
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Affiliation(s)
- Brigid K Jensen
- Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA.
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16
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Nardin C, Mammano F. Measurement of Ca 2+ Uptake Through Connexin Hemichannels. Methods Mol Biol 2024; 2801:97-109. [PMID: 38578416 DOI: 10.1007/978-1-0716-3842-2_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
Increasing evidence points to deregulated flux of ionized calcium (Ca2+) mediated by hyperactive mutant connexin (Cx) hemichannels (HCs) as a common gain-of-function etiopathogenetic mechanism for several diseases, ranging from skin disorders to nervous system defects. Furthermore, the opening of nonmutated Cx HCs is associated with an impressive list of widespread diseases including, but not limited to, ischemia/stroke, Alzheimer's disease, and epilepsy. HC inhibitors are attracting a growing attention due to their therapeutic potential for numerous pathologies. This chapter describes a quantitative method to measure Ca2+ uptake though HCs expressed in cultured cells. The assay we developed can be used to probe HC activity as wells as to test HC inhibitors. Furthermore, with minor changes it can be easily adapted to high-throughput high-content platforms and/or primary cells and microtissues.
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Affiliation(s)
- Chiara Nardin
- Institute of Biochemistry and Cell Biology, Italian National Research Council, Rome, Italy
- , Genoa, Italy
| | - Fabio Mammano
- Institute of Biochemistry and Cell Biology, Italian National Research Council, Rome, Italy.
- Department of Physics and Astronomy "G. Galilei", University of Padova, Padova, Italy.
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17
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Provenzano F, Torazza C, Bonifacino T, Bonanno G, Milanese M. The Key Role of Astrocytes in Amyotrophic Lateral Sclerosis and Their Commitment to Glutamate Excitotoxicity. Int J Mol Sci 2023; 24:15430. [PMID: 37895110 PMCID: PMC10607805 DOI: 10.3390/ijms242015430] [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: 08/25/2023] [Revised: 10/12/2023] [Accepted: 10/19/2023] [Indexed: 10/29/2023] Open
Abstract
In the last two decades, there has been increasing evidence supporting non-neuronal cells as active contributors to neurodegenerative disorders. Among glial cells, astrocytes play a pivotal role in driving amyotrophic lateral sclerosis (ALS) progression, leading the scientific community to focus on the "astrocytic signature" in ALS. Here, we summarized the main pathological mechanisms characterizing astrocyte contribution to MN damage and ALS progression, such as neuroinflammation, mitochondrial dysfunction, oxidative stress, energy metabolism impairment, miRNAs and extracellular vesicles contribution, autophagy dysfunction, protein misfolding, and altered neurotrophic factor release. Since glutamate excitotoxicity is one of the most relevant ALS features, we focused on the specific contribution of ALS astrocytes in this aspect, highlighting the known or potential molecular mechanisms by which astrocytes participate in increasing the extracellular glutamate level in ALS and, conversely, undergo the toxic effect of the excessive glutamate. In this scenario, astrocytes can behave as "producers" and "targets" of the high extracellular glutamate levels, going through changes that can affect themselves and, in turn, the neuronal and non-neuronal surrounding cells, thus actively impacting the ALS course. Moreover, this review aims to point out knowledge gaps that deserve further investigation.
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Affiliation(s)
- Francesca Provenzano
- Department of Pharmacy (DIFAR), University of Genoa, 16148 Genova, Italy; (F.P.); (C.T.); (G.B.); (M.M.)
| | - Carola Torazza
- Department of Pharmacy (DIFAR), University of Genoa, 16148 Genova, Italy; (F.P.); (C.T.); (G.B.); (M.M.)
| | - Tiziana Bonifacino
- Department of Pharmacy (DIFAR), University of Genoa, 16148 Genova, Italy; (F.P.); (C.T.); (G.B.); (M.M.)
- Inter-University Center for the Promotion of the 3Rs Principles in Teaching & Research (Centro 3R), 56122 Pisa, Italy
| | - Giambattista Bonanno
- Department of Pharmacy (DIFAR), University of Genoa, 16148 Genova, Italy; (F.P.); (C.T.); (G.B.); (M.M.)
| | - Marco Milanese
- Department of Pharmacy (DIFAR), University of Genoa, 16148 Genova, Italy; (F.P.); (C.T.); (G.B.); (M.M.)
- IRCCS Ospedale Policlinico San Martino, 16132 Genoa, Italy
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18
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Gonzalez H, Narasipura SD, Shull T, Shetty A, Teppen TL, Naqib A, Al-Harthi L. An Efficient and Cost-Effective Approach to Generate Functional Human Inducible Pluripotent Stem Cell-Derived Astrocytes. Cells 2023; 12:2357. [PMID: 37830571 PMCID: PMC10571578 DOI: 10.3390/cells12192357] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 09/11/2023] [Accepted: 09/16/2023] [Indexed: 10/14/2023] Open
Abstract
Human inducible pluripotent stem cell (hiPSC)-derived astrocytes (iAs) are critical to study astrocytes in health and disease. They provide several advantages over human fetal astrocytes in research, which include consistency, availability, disease modeling, customization, and ethical considerations. The generation of iAs is hampered by the requirement of Matrigel matrix coating for survival and proliferation. We provide a protocol demonstrating that human iAs cultured in the absence of Matrigel are viable and proliferative. Further, through a side-by-side comparison of cultures with and without Matrigel, we show significant similarities in astrocyte-specific profiling, including morphology (shape and structure), phenotype (cell-specific markers), genotype (transcriptional expression), metabolic (respiration), and functional aspects (glutamate uptake and cytokine response). In addition, we report that, unlike other CNS cell types, such as neuronal progenitor cells and neurons, iAs can withstand the absence of Matrigel coating. Our study demonstrates that Matrigel is dispensable for the culture of human iPSC-derived astrocytes, facilitating an easy, streamlined, and cost-effective method of generating these cells.
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Affiliation(s)
- Hemil Gonzalez
- Department of Internal Medicine, Division of Infectious Diseases, Rush University Medical Center, Chicago, IL 60612, USA
- Department of Microbial Pathogens and Immunity, Rush Medical College, Chicago, IL 60612, USA; (S.D.N.); (T.S.)
| | - Srinivas D. Narasipura
- Department of Microbial Pathogens and Immunity, Rush Medical College, Chicago, IL 60612, USA; (S.D.N.); (T.S.)
| | - Tanner Shull
- Department of Microbial Pathogens and Immunity, Rush Medical College, Chicago, IL 60612, USA; (S.D.N.); (T.S.)
- Division of Epidemiology and Biostatistics, School of Public Health, University of Illinois, Chicago, IL 60608, USA
| | - Amogh Shetty
- Illinois Mathematics and Science Academy, Aurora, IL 60506, USA
| | - Tara L. Teppen
- Molecular Neurobiology Division, Rush Alzheimer’s Disease Center, Rush University, Chicago, IL 60612, USA
| | - Ankur Naqib
- Genome Core Facility, Rush University, Chicago, IL 60612, USA;
| | - Lena Al-Harthi
- Department of Microbial Pathogens and Immunity, Rush Medical College, Chicago, IL 60612, USA; (S.D.N.); (T.S.)
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19
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Ahn YH, Tang Y, Illes P. The neuroinflammatory astrocytic P2X7 receptor: Alzheimer's disease, ischemic brain injury, and epileptic state. Expert Opin Ther Targets 2023; 27:763-778. [PMID: 37712394 DOI: 10.1080/14728222.2023.2258281] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 08/04/2023] [Accepted: 09/08/2023] [Indexed: 09/16/2023]
Abstract
INTRODUCTION Astrocytes have previously been considered as cells supporting neuronal functions, but they are now recognized as active players in maintaining central nervous system (CNS) homeostasis. Astrocytes can communicate with other CNS cells, i.e. through the gliotransmitter ATP and P2X7 receptors (Rs). AREAS COVERED In this review, we will discuss how the P2X7R initiates the release of gliotransmitters and proinflammatory cytokines/chemokines, thereby establishing a dialog between astrocytes and neurons and, in addition, causing neuroinflammation. In astrocytes, dysregulation of P2X7Rs has been associated with neurodegenerative illnesses such as Alzheimer's disease (AD), as well as the consequences of cerebral ischemic injury and status epilepticus (SE). EXPERT OPINION Although all CNS cells are possible sources of ATP release, the targets of this ATP are primarily at microglial cells. However, astrocytes also contain ATP-sensitive P2X7Rs and have in addition the peculiar property over microglia to continuously interact with neurons via not only inflammatory mediators but also gliotransmitters, such as adenosine 5'-triphosphate (ATP), glutamate, γ-amino butyric acid (GABA), and D-serine. Cellular damage arising during AD, cerebral ischemia, and SE via P2X7R activation is superimposed upon the original disease, and their prevention by blood-brain barrier permeable pharmacological antagonists is a valid therapeutic option.
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Affiliation(s)
- Young Ha Ahn
- International Joint Research Center on Purinergic Signaling of Sichuan Province, Chengdu University of TCM, Chengdu, China
| | - Yong Tang
- International Joint Research Center on Purinergic Signaling of Sichuan Province, Chengdu University of TCM, Chengdu, China
- School of Acupuncture and Tuina, Chengdu University of TCM, Chengdu, China
| | - Peter Illes
- International Joint Research Center on Purinergic Signaling of Sichuan Province, Chengdu University of TCM, Chengdu, China
- Rudolf Boehm Institute of Pharmacology and Toxicology, University of Leipzig, Leipzig, Germany
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20
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Toro CA, Johnson K, Hansen J, Siddiq MM, Vásquez W, Zhao W, Graham ZA, Sáez JC, Iyengar R, Cardozo CP. Boldine modulates glial transcription and functional recovery in a murine model of contusion spinal cord injury. Front Cell Neurosci 2023; 17:1163436. [PMID: 37416508 PMCID: PMC10321410 DOI: 10.3389/fncel.2023.1163436] [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: 02/10/2023] [Accepted: 06/01/2023] [Indexed: 07/08/2023] Open
Abstract
Membrane channels such as those formed by connexins (Cx) and P2X7 receptors (P2X7R) are permeable to calcium ions and other small molecules such as adenosine triphosphate (ATP) and glutamate. Release of ATP and glutamate through these channels is a key mechanism driving tissue response to traumas such as spinal cord injury (SCI). Boldine, an alkaloid isolated from the Chilean boldo tree, blocks both Cx and Panx1 hemichannels (HCs). To test if boldine could improve function after SCI, boldine or vehicle was administered to treat mice with a moderate severity contusion-induced SCI. Boldine led to greater spared white matter and increased locomotor function as determined by the Basso Mouse Scale and horizontal ladder rung walk tests. Boldine treatment reduced immunostaining for markers of activated microglia (Iba1) and astrocytic (GFAP) markers while increasing that for axon growth and neuroplasticity (GAP-43). Cell culture studies demonstrated that boldine blocked glial HC, specifically Cx26 and Cx30, in cultured astrocytes and blocked calcium entry through activated P2X7R. RT-qPCR studies showed that boldine treatment reduced expression of the chemokine Ccl2, cytokine IL-6 and microglial gene CD68, while increasing expression of the neurotransmission genes Snap25 and Grin2b, and Gap-43. Bulk RNA sequencing revealed that boldine modulated a large number of genes involved in neurotransmission in spinal cord tissue just caudal from the lesion epicenter at 14 days after SCI. Numbers of genes regulated by boldine was much lower at 28 days after injury. These results indicate that boldine treatment ameliorates injury and spares tissue to increase locomotor function.
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Affiliation(s)
- Carlos A. Toro
- Spinal Cord Damage Research Center, James J. Peters VA Medical Center, Bronx, NY, United States
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Kaitlin Johnson
- Spinal Cord Damage Research Center, James J. Peters VA Medical Center, Bronx, NY, United States
| | - Jens Hansen
- Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Mustafa M. Siddiq
- Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Institute for Systems Biomedicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Walter Vásquez
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile
- Instituto de Neurociencias, Centro Interdisciplinario De Neurociencia De Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Wei Zhao
- Spinal Cord Damage Research Center, James J. Peters VA Medical Center, Bronx, NY, United States
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Zachary A. Graham
- Florida Institute for Human and Machine Cognition, Pensacola, FL, United States
- Department of Cell, Developmental, and Integrative Biology, University of Alabama, Birmingham, AL, United States
- Research Service, Birmingham Veterans Affairs Health Care System, Birmingham, AL, United States
| | - Juan C. Sáez
- Instituto de Neurociencias, Centro Interdisciplinario De Neurociencia De Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Ravi Iyengar
- Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Institute for Systems Biomedicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Christopher P. Cardozo
- Spinal Cord Damage Research Center, James J. Peters VA Medical Center, Bronx, NY, United States
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Rehabilitative Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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21
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Aten S, Du Y, Taylor O, Dye C, Collins K, Thomas M, Kiyoshi C, Zhou M. Chronic Stress Impairs the Structure and Function of Astrocyte Networks in an Animal Model of Depression. Neurochem Res 2023; 48:1191-1210. [PMID: 35796915 PMCID: PMC9823156 DOI: 10.1007/s11064-022-03663-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 06/18/2022] [Indexed: 01/11/2023]
Abstract
Now astrocytes appear to be the key contributors to the pathophysiology of major depression. Evidence in rodents shows that chronic stress is associated with a decreased expression of astrocytic GFAP-immunoreactivity within the cortex in addition to changes in the complexity and length of astrocyte processes. Furthermore, postmortem brains of individuals with depression have revealed a decrease in astrocyte density. Notably, astrocytes are extensively coupled to one another through gap junctions to form a network, or syncytium, and we have previously demonstrated that syncytial isopotentiality is a mechanism by which astrocytes function as an efficient system with respect to brain homeostasis. Interestingly, the question of how astrocyte network function changes following chronic stress is yet to be elucidated. Here, we sought to examine the effects of chronic stress on network-level astrocyte (dys)function. Using a transgenic aldh1l1-eGFP astrocyte reporter mouse, a six-week unpredictable chronic mild stress (UCMS) paradigm as a rodent model of major depression, and immunohistochemical approaches, we show that the morphology of individual astrocytes is altered by chronic stress exposure. Additionally, in astrocyte syncytial isopotentiality measurement, we found that UCMS impairs the syncytial coupling strength of astrocytes within the hippocampus and prefrontal cortex-two brain regions that have been implicated in the regulation of mood. Together, these findings reveal that chronic stress leads to astrocyte atrophy and impaired gap junction coupling, raising the prospect that both individual and network-level astrocyte functionality are important in the etiology of major depression and other neuropsychiatric disorders.
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Affiliation(s)
- Sydney Aten
- Department of Neuroscience, Ohio State University Wexner Medical Center, Graves Hall, Rm 4066C, 333 W. 10th Ave, Columbus, OH, 43210, USA
- Department of Neurology, Division of Sleep Medicine, and Program in Neuroscience, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Yixing Du
- Department of Neuroscience, Ohio State University Wexner Medical Center, Graves Hall, Rm 4066C, 333 W. 10th Ave, Columbus, OH, 43210, USA
| | - Olivia Taylor
- Department of Neuroscience, Ohio State University Wexner Medical Center, Graves Hall, Rm 4066C, 333 W. 10th Ave, Columbus, OH, 43210, USA
| | - Courtney Dye
- Department of Neuroscience, Ohio State University Wexner Medical Center, Graves Hall, Rm 4066C, 333 W. 10th Ave, Columbus, OH, 43210, USA
| | - Kelsey Collins
- Department of Neuroscience, Ohio State University Wexner Medical Center, Graves Hall, Rm 4066C, 333 W. 10th Ave, Columbus, OH, 43210, USA
| | - Matthew Thomas
- Department of Neuroscience, Ohio State University Wexner Medical Center, Graves Hall, Rm 4066C, 333 W. 10th Ave, Columbus, OH, 43210, USA
| | - Conrad Kiyoshi
- Department of Neuroscience, Ohio State University Wexner Medical Center, Graves Hall, Rm 4066C, 333 W. 10th Ave, Columbus, OH, 43210, USA
- Northern Marianas College, Saipan, MP, USA
| | - Min Zhou
- Department of Neuroscience, Ohio State University Wexner Medical Center, Graves Hall, Rm 4066C, 333 W. 10th Ave, Columbus, OH, 43210, USA.
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22
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Giantomasi L, Ribeiro JF, Barca-Mayo O, Malerba M, Miele E, De Pietri Tonelli D, Berdondini L. Astrocytes actively support long-range molecular clock synchronization of segregated neuronal populations. Sci Rep 2023; 13:4815. [PMID: 36964220 PMCID: PMC10038999 DOI: 10.1038/s41598-023-31966-1] [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: 08/09/2022] [Accepted: 03/20/2023] [Indexed: 03/26/2023] Open
Abstract
In mammals, the suprachiasmatic nucleus of the hypothalamus is the master circadian pacemaker that synchronizes the clocks in the central nervous system and periphery, thus orchestrating rhythms throughout the body. However, little is known about how so many cellular clocks within and across brain circuits can be effectively synchronized. In this work, we investigated the implication of two possible pathways: (i) astrocytes-mediated synchronization and (ii) neuronal paracrine factors-mediated synchronization. By taking advantage of a lab-on-a-chip microfluidic device developed in our laboratory, here we report that both pathways are involved. We found the paracrine factors-mediated synchronization of molecular clocks is diffusion-limited and, in our device, effective only in case of a short distance between neuronal populations. Interestingly, interconnecting astrocytes define an active signaling channel that can synchronize molecular clocks of neuronal populations also at longer distances. At mechanism level, we found that astrocytes-mediated synchronization involves both GABA and glutamate, while neuronal paracrine factors-mediated synchronization occurs through GABA signaling. These findings identify a previously unknown role of astrocytes as active cells that might distribute long-range signals to synchronize the brain clocks, thus further strengthening the importance of reciprocal interactions between glial and neuronal cells in the context of circadian circuitry.
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Affiliation(s)
- Lidia Giantomasi
- Microtechnology for Neuroelectronics, Fondazione Istituto Italiano Di Tecnologia (IIT), 16163, Genova, Italy
| | - João F Ribeiro
- Microtechnology for Neuroelectronics, Fondazione Istituto Italiano Di Tecnologia (IIT), 16163, Genova, Italy
| | - Olga Barca-Mayo
- Neurobiology of miRNA, Fondazione Istituto Italiano Di Tecnologia (IIT), 16163, Genova, Italy
- Circadian and Glial Biology Lab, Physiology Department, Molecular Medicine, and Chronic Diseases Research Centre (CiMUS), University of Santiago de Compostela, Santiago de Compostela, Spain
| | - Mario Malerba
- Microtechnology for Neuroelectronics, Fondazione Istituto Italiano Di Tecnologia (IIT), 16163, Genova, Italy
- Centre de Nanosciences et de Nanotechnologies (C2N), CNRS UMR 9001, Université Paris-Saclay, 91120, Palaiseau, France
| | - Ermanno Miele
- Microtechnology for Neuroelectronics, Fondazione Istituto Italiano Di Tecnologia (IIT), 16163, Genova, Italy
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, UK
| | | | - Luca Berdondini
- Microtechnology for Neuroelectronics, Fondazione Istituto Italiano Di Tecnologia (IIT), 16163, Genova, Italy.
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23
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Toro CA, Johnson K, Hansen J, Siddiq MM, Vásquez W, Zhao W, Graham ZA, Sáez JC, Iyengar R, Cardozo CP. Boldine modulates glial transcription and functional recovery in a murine model of contusion spinal cord injury. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.15.528337. [PMID: 36824813 PMCID: PMC9949031 DOI: 10.1101/2023.02.15.528337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Membrane channels such as connexins (Cx), pannexins (Panx) and P2X 7 receptors (P2X 7 R) are permeable to calcium ions and other small molecules such as ATP and glutamate. Release of ATP and glutamate through these channels is a key mechanism driving tissue response to traumas such as spinal cord injury (SCI). Boldine, an alkaloid isolated from the Chilean boldo tree, blocks both Cx hemichannels (HC) and Panx. To test if boldine could improve function after SCI, boldine or vehicle was administered to treat mice with a moderate severity contusion-induced SCI. Boldine led to greater spared white matter and increased locomotor function as determined by the Basso Mouse Scale and horizontal ladder rung walk tests. Boldine treatment reduced immunostaining for markers of activated microglia (Iba1) and astrocytic (GFAP) markers while increasing that for axon growth and neuroplasticity (GAP-43). Cell culture studies demonstrated that boldine blocked glial HC, specifically Cx26 and Cx30, in cultured astrocytes and blocked calcium entry through activated P2X 7 R. RT-qPCR studies showed that boldine treatment reduced expression of the chemokine Ccl2, cytokine IL-6 and microglial gene CD68, while increasing expression of the neurotransmission genes Snap25 and Grin2b, and Gap-43. Bulk RNA sequencing (of the spinal cord revealed that boldine modulated a large number of genes involved in neurotransmission in in spinal cord tissue just below the lesion epicenter at 14 days after SCI. Numbers of genes regulated by boldine was much lower at 28 days after injury. These results indicate that boldine treatment ameliorates injury and spares tissue to increase locomotor function.
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24
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Pun R, Kim MH, North BJ. Role of Connexin 43 phosphorylation on Serine-368 by PKC in cardiac function and disease. Front Cardiovasc Med 2023; 9:1080131. [PMID: 36712244 PMCID: PMC9877470 DOI: 10.3389/fcvm.2022.1080131] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Accepted: 12/19/2022] [Indexed: 01/13/2023] Open
Abstract
Intercellular communication mediated by gap junction channels and hemichannels composed of Connexin 43 (Cx43) is vital for the propagation of electrical impulses through cardiomyocytes. The carboxyl terminal tail of Cx43 undergoes various post-translational modifications including phosphorylation of its Serine-368 (S368) residue. Protein Kinase C isozymes directly phosphorylate S368 to alter Cx43 function and stability through inducing conformational changes affecting channel permeability or promoting internalization and degradation to reduce intercellular communication between cardiomyocytes. Recent studies have implicated this PKC/Cx43-pS368 circuit in several cardiac-associated diseases. In this review, we describe the molecular and cellular basis of PKC-mediated Cx43 phosphorylation and discuss the implications of Cx43 S368 phosphorylation in the context of various cardiac diseases, such as cardiomyopathy, as well as the therapeutic potential of targeting this pathway.
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Affiliation(s)
- Renju Pun
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE, United States
| | - Michael H. Kim
- CHI Health Heart Institute, School of Medicine, Creighton University, Omaha, NE, United States
| | - Brian J. North
- Department of Biomedical Sciences, School of Medicine, Creighton University, Omaha, NE, United States,*Correspondence: Brian J. North,
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25
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Gudkov SV, Burmistrov DE, Kondakova EV, Sarimov RM, Yarkov RS, Franceschi C, Vedunova MV. An emerging role of astrocytes in aging/neuroinflammation and gut-brain axis with consequences on sleep and sleep disorders. Ageing Res Rev 2023; 83:101775. [PMID: 36334910 DOI: 10.1016/j.arr.2022.101775] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 10/05/2022] [Accepted: 10/30/2022] [Indexed: 11/18/2022]
Abstract
Understanding the role of astrocytes in the central nervous system has changed dramatically over the last decade. The accumulating findings indicate that glial cells are involved not only in the maintenance of metabolic and ionic homeostasis and in the implementation of trophic functions but also in cognitive functions and information processing in the brain. Currently, there are some controversies regarding the role of astrocytes in complex processes such as aging of the nervous system and the pathogenesis of age-related neurodegenerative diseases. Many findings confirm the important functional role of astrocytes in age-related brain changes, including sleep disturbance and the development of neurodegenerative diseases and particularly Alzheimer's disease. Until recent years, neurobiological research has focused mainly on neuron-glial interactions, in which individual astrocytes locally modulate neuronal activity and communication between neurons. The review considers the role of astrocytes in the physiology of sleep and as an important "player" in the development of neurodegenerative diseases. In addition, the features of the astrocytic network reorganization during aging are discussed.
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Affiliation(s)
- Sergey V Gudkov
- Prokhorov General Physics Institute of the Russian Academy of Sciences, 38 Vavilov str., 119991 Moscow, Russia; Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin ave., 603022 Nizhny Novgorod, Russia.
| | - Dmitriy E Burmistrov
- Prokhorov General Physics Institute of the Russian Academy of Sciences, 38 Vavilov str., 119991 Moscow, Russia.
| | - Elena V Kondakova
- Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin ave., 603022 Nizhny Novgorod, Russia.
| | - Ruslan M Sarimov
- Prokhorov General Physics Institute of the Russian Academy of Sciences, 38 Vavilov str., 119991 Moscow, Russia.
| | - Roman S Yarkov
- Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin ave., 603022 Nizhny Novgorod, Russia.
| | - Claudio Franceschi
- Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin ave., 603022 Nizhny Novgorod, Russia.
| | - Maria V Vedunova
- Institute of Biology and Biomedicine, Lobachevsky State University of Nizhny Novgorod, 23 Gagarin ave., 603022 Nizhny Novgorod, Russia.
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26
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Old and Promising Markers Related to Autophagy in Traumatic Brain Injury. Int J Mol Sci 2022; 24:ijms24010072. [PMID: 36613513 PMCID: PMC9820105 DOI: 10.3390/ijms24010072] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 12/15/2022] [Accepted: 12/16/2022] [Indexed: 12/24/2022] Open
Abstract
Traumatic brain injury (TBI) is one of the first causes of death and disability in the world. Because of the lack of macroscopical or histologic evidence of the damage, the forensic diagnosis of TBI could be particularly difficult. Considering that the activation of autophagy in the brain after a TBI is well documented in literature, the aim of this review is to find all autophagy immunohistological protein markers that are modified after TBI to propose a method to diagnose this eventuality in the brain of trauma victims. A systematic literature review on PubMed following PRISMA 2020 guidelines has enabled the identification of 241 articles. In all, 21 of these were enrolled to identify 24 markers that could be divided into two groups. The first consisted of well-known markers that could be considered for a first diagnosis of TBI. The second consisted of new markers recently proposed in the literature that could be used in combination with the markers of the first group to define the elapsed time between trauma and death. However, the use of these markers has to be validated in the future in human tissue by further studies, and the influence of other diseases affecting the victims before death should be explored.
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27
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Benedikt J, Malpica-Nieves CJ, Rivera Y, Méndez-González M, Nichols CG, Veh RW, Eaton MJ, Skatchkov SN. The Polyamine Spermine Potentiates the Propagation of Negatively Charged Molecules through the Astrocytic Syncytium. Biomolecules 2022; 12:biom12121812. [PMID: 36551240 PMCID: PMC9775384 DOI: 10.3390/biom12121812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/16/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022] Open
Abstract
The interest in astrocytes, the silent brain cells that accumulate polyamines (PAs), is growing. PAs exert anti-inflammatory, antioxidant, antidepressant, neuroprotective, and other beneficial effects, including increasing longevity in vivo. Unlike neurons, astrocytes are extensively coupled to others via connexin (Cx) gap junctions (GJs). Although there are striking modulatory effects of PAs on neuronal receptors and channels, PA regulation of the astrocytic GJs is not well understood. We studied GJ-propagation using molecules of different (i) electrical charge, (ii) structure, and (iii) molecular weight. Loading single astrocytes with patch pipettes containing membrane-impermeable dyes, we observed that (i) even small molecules do not easily permeate astrocytic GJs, (ii) the ratio of the charge to weight of these molecules is the key determinant of GJ permeation, (iii) the PA spermine (SPM) induced the propagation of negatively charged molecules via GJs, (iv) while no effects were observed on propagation of macromolecules with net-zero charge. The GJ uncoupler carbenoxolone (CBX) blocked such propagation. Taken together, these findings indicate that SPM is essential for astrocytic GJ communication and selectively facilitates intracellular propagation via GJs for negatively charged molecules through glial syncytium.
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Affiliation(s)
- Jan Benedikt
- Department of Physiology, Universidad Central del Caribe, Bayamón, PR 00956, USA
| | - Christian J. Malpica-Nieves
- Department of Biochemistry, Universidad Central del Caribe, Bayamón, PR 00956, USA
- Correspondence: (C.J.M.-N.); (S.N.S.); Tel.: +1-787-798-3001 (ext. 2057) (S.N.S.)
| | - Yomarie Rivera
- Department of Chiropractic, Universidad Central del Caribe, Bayamón, PR 00956, USA
| | | | - Colin G. Nichols
- Department of Cell Biology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Rüdiger W. Veh
- Institut für Zell- und Neurobiologie, Charité, 10115 Berlin, Germany
| | - Misty J. Eaton
- Department of Biochemistry, Universidad Central del Caribe, Bayamón, PR 00956, USA
| | - Serguei N. Skatchkov
- Department of Physiology, Universidad Central del Caribe, Bayamón, PR 00956, USA
- Department of Biochemistry, Universidad Central del Caribe, Bayamón, PR 00956, USA
- Correspondence: (C.J.M.-N.); (S.N.S.); Tel.: +1-787-798-3001 (ext. 2057) (S.N.S.)
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28
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Insulin and IGF-1 elicit robust transcriptional regulation to modulate autophagy in astrocytes. Mol Metab 2022; 66:101647. [PMID: 36503893 PMCID: PMC9731889 DOI: 10.1016/j.molmet.2022.101647] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 11/08/2022] [Accepted: 11/23/2022] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE Insulin is a principal metabolic hormone. It regulates a plethora of metabolic pathways in peripheral tissues. The highly homologous insulin-like growth factor 1 (IGF-1), on the other hand, is important for development and growth. Recent studies have shown that insulin and IGF-1 signaling plays fundamental roles in the brain. Loss of insulin or IGF-1 receptors in astrocytes leads to altered glucose handling, mitochondrial metabolism, neurovascular coupling, and behavioral abnormalities in mice. Here, we aim to investigate molecular mechanisms by which insulin and IGF-1 signaling regulates astrocyte functions. METHODS IR-flox and IRKO primary astrocytes were treated with 100 nM insulin or IGF-1 for 6 h, and their transcriptomes were analyzed. Astrocytes with either IR deletion, IGF1R deletion or both were used to examine receptor-dependent transcriptional regulations using qPCR. Additional immunoblotting and confocal imaging studies were performed to functionally validate pathways involved in protein homeostasis. RESULTS Using next-generation RNA sequencing, we show that insulin significantly regulates the expression of over 1,200 genes involved in multiple functional processes in primary astrocytes. Insulin-like growth factor 1 (IGF-1) triggers a similar robust transcriptional regulation in astrocytes. Thus, over 50% of the differentially expressed genes are regulated by both ligands. As expected, these commonly regulated genes are highly enriched in pathways involved in lipid and cholesterol biosynthesis. Additionally, insulin and IGF-1 induce the expression of genes involved in ribosomal biogenesis, while suppressing the expression of genes involved in autophagy, indicating a common role of insulin and IGF-1 on protein homeostasis in astrocytes. Insulin-dependent suppression of autophagy genes, including p62, Ulk1/2, and several Atg genes, is blunted only when both IR and IGF1R are deleted. CONCLUSIONS In summary, insulin and IGF-1 potently suppress autophagy in astrocytes through transcriptional regulation. Both IR and IGF1R can elicit ligand-dependent transcriptional suppression of autophagy. These results demonstrate an important role of astrocytic insulin/IGF-1 signaling on proteostasis. Impairment of this regulation in insulin resistance and diabetes may contribute to neurological complications related to diabetes.
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29
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Oliveira MC, Verswyvel H, Smits E, Cordeiro RM, Bogaerts A, Lin A. The pro- and anti-tumoral properties of gap junctions in cancer and their role in therapeutic strategies. Redox Biol 2022; 57:102503. [PMID: 36228438 PMCID: PMC9557036 DOI: 10.1016/j.redox.2022.102503] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 09/06/2022] [Accepted: 10/06/2022] [Indexed: 11/24/2022] Open
Abstract
Gap junctions (GJs), essential structures for cell-cell communication, are made of two hemichannels (commonly called connexons), one on each adjacent cell. Found in almost all cells, GJs play a pivotal role in many physiological and cellular processes, and have even been linked to the progression of diseases, such as cancer. Modulation of GJs is under investigation as a therapeutic strategy to kill tumor cells. Furthermore, GJs have also been studied for their key role in activating anti-cancer immunity and propagating radiation- and oxidative stress-induced cell death to neighboring cells, a process known as the bystander effect. While, gap junction (GJ)-based therapeutic strategies are being developed, one major challenge has been the paradoxical role of GJs in both tumor progression and suppression, based on GJ composition, cancer factors, and tumoral context. Therefore, understanding the mechanisms of action, regulation, and the dual characteristics of GJs in cancer is critical for developing effective therapeutics. In this review, we provide an overview of the current understanding of GJs structure, function, and paradoxical pro- and anti-tumoral role in cancer. We also discuss the treatment strategies to target these GJs properties for anti-cancer responses, via modulation of GJ function.
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Affiliation(s)
- Maria C Oliveira
- Plasma Lab for Applications in Sustainability and Medicine-Antwerp (PLASMANT), Department of Chemistry, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium; Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Avenida dos Estados 5001, CEP 09210-580, Santo André, SP, Brazil.
| | - Hanne Verswyvel
- Plasma Lab for Applications in Sustainability and Medicine-Antwerp (PLASMANT), Department of Chemistry, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium; Center for Oncological Research (CORE), Integrated Personalized and Precision Oncology Network (IPPON), University of Antwerp, Universiteitsplein 1, B-2610, Antwerp, Belgium
| | - Evelien Smits
- Center for Oncological Research (CORE), Integrated Personalized and Precision Oncology Network (IPPON), University of Antwerp, Universiteitsplein 1, B-2610, Antwerp, Belgium
| | - Rodrigo M Cordeiro
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Avenida dos Estados 5001, CEP 09210-580, Santo André, SP, Brazil
| | - Annemie Bogaerts
- Plasma Lab for Applications in Sustainability and Medicine-Antwerp (PLASMANT), Department of Chemistry, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium
| | - Abraham Lin
- Plasma Lab for Applications in Sustainability and Medicine-Antwerp (PLASMANT), Department of Chemistry, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium; Center for Oncological Research (CORE), Integrated Personalized and Precision Oncology Network (IPPON), University of Antwerp, Universiteitsplein 1, B-2610, Antwerp, Belgium
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30
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Su PYP, Zhang L, He L, Zhao N, Guan Z. The Role of Neuro-Immune Interactions in Chronic Pain: Implications for Clinical Practice. J Pain Res 2022; 15:2223-2248. [PMID: 35957964 PMCID: PMC9359791 DOI: 10.2147/jpr.s246883] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 07/19/2022] [Indexed: 11/23/2022] Open
Abstract
Chronic pain remains a public health problem and contributes to the ongoing opioid epidemic. Current pain management therapies still leave many patients with poorly controlled pain, thus new or improved treatments are desperately needed. One major challenge in pain research is the translation of preclinical findings into effective clinical practice. The local neuroimmune interface plays an important role in the initiation and maintenance of chronic pain and is therefore a promising target for novel therapeutic development. Neurons interface with immune and immunocompetent cells in many distinct microenvironments along the nociceptive circuitry. The local neuroimmune interface can modulate the activity and property of the neurons to affect peripheral and central sensitization. In this review, we highlight a specific subset of many neuroimmune interfaces. In the central nervous system, we examine the interface between neurons and microglia, astrocytes, and T lymphocytes. In the periphery, we profile the interface between neurons in the dorsal root ganglion with T lymphocytes, satellite glial cells, and macrophages. To bridge the gap between preclinical research and clinical practice, we review the preclinical studies of each neuroimmune interface, discuss current clinical treatments in pain medicine that may exert its action at the neuroimmune interface, and highlight opportunities for future clinical research efforts.
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Affiliation(s)
- Po-Yi Paul Su
- Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, CA, USA
| | - Lingyi Zhang
- Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, CA, USA
- Department of Anesthesiology, the First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, People’s Republic of China
| | - Liangliang He
- Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, CA, USA
- Department of Pain Management, Xuanwu Hospital, Capital Medical University, Beijing, People’s Republic of China
| | - Na Zhao
- Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, CA, USA
| | - Zhonghui Guan
- Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, CA, USA
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Looking to the stars for answers: Strategies for determining how astrocytes influence neuronal activity. Comput Struct Biotechnol J 2022; 20:4146-4156. [PMID: 36016711 PMCID: PMC9379862 DOI: 10.1016/j.csbj.2022.07.052] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 07/29/2022] [Accepted: 07/29/2022] [Indexed: 11/24/2022] Open
Abstract
Astrocytes are critical components of neural circuits positioned in close proximity to the synapse, allowing them to rapidly sense and respond to neuronal activity. One repeatedly observed biomarker of astroglial activation is an increase in intracellular Ca2+ levels. These astroglial Ca2+ signals are often observed spreading throughout various cellular compartments from perisynaptic astroglial processes, to major astrocytic branches and on to the soma or cell body. Here we review recent evidence demonstrating that astrocytic Ca2+ events are remarkably heterogeneous in both form and function, propagate through the astroglial syncytia, and are directly linked to the ability of astroglia to influence local neuronal activity. As many of the cellular functions of astroglia can be linked to intracellular Ca2+ signaling, and the diversity and heterogeneity of these events becomes more apparent, there is an increasing need for novel experimental strategies designed to better understand the how these signals evolve in parallel with neuronal activity. Here we review the recent advances that enable the characterization of both subcellular and population-wide astrocytic Ca2+ dynamics. Additionally, we also outline the experimental design required for simultaneous in vivo Ca2+ imaging in the context of neuronal or astroglial manipulation, highlighting new experimental strategies made possible by recent advances in viral vector, imaging, and quantification technologies. Through combined usage of these reagents and methodologies, we provide a conceptual framework to study how astrocytes functionally integrate into neural circuits and to what extent they influence and direct the synaptic activity underlying behavioral responses.
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A Quantitative Assay for Ca2+ Uptake through Normal and Pathological Hemichannels. Int J Mol Sci 2022; 23:ijms23137337. [PMID: 35806342 PMCID: PMC9266989 DOI: 10.3390/ijms23137337] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 06/26/2022] [Accepted: 06/28/2022] [Indexed: 12/25/2022] Open
Abstract
Connexin (Cx) hemichannels (HCs) are large pore hexameric structures that allow the exchange of ions, metabolites and a variety of other molecules between the cell cytoplasm and extracellular milieu. HC inhibitors are attracting growing interest as drug candidates because deregulated fluxes through HCs have been implicated in a plethora of genetic conditions and other diseases. HC activity has been mainly investigated by electrophysiological methods and/or using HC-permeable dye uptake measurements. Here, we present an all-optical assay based on fluorometric measurements of ionized calcium (Ca2+) uptake with a Ca2+-selective genetically encoded indicator (GCaMP6s) that permits the optical tracking of cytosolic Ca2+ concentration ([Ca2+]cyt) changes with high sensitivity. We exemplify use of the assay in stable pools of HaCaT cells overexpressing human Cx26, Cx46, or the pathological mutant Cx26G45E, under control of a tetracycline (Tet) responsive element (TRE) promoter (Tet-on). We demonstrate the usefulness of the assay for the characterization of new monoclonal antibodies (mAbs) targeting the extracellular domain of the HCs. Although we developed the assay on a spinning disk confocal fluorescence microscope, the same methodology can be extended seamlessly to high-throughput high-content platforms to screen other kinds of inhibitors and/or to probe HCs expressed in primary cells and microtissues.
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Choi IS, Kim JH, Jeong JY, Lee MG, Suk K, Jang IS. Astrocyte-derived adenosine excites sleep-promoting neurons in the ventrolateral preoptic nucleus: Astrocyte-neuron interactions in the regulation of sleep. Glia 2022; 70:1864-1885. [PMID: 35638268 DOI: 10.1002/glia.24225] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 05/16/2022] [Accepted: 05/17/2022] [Indexed: 11/10/2022]
Abstract
Although ATP and/or adenosine derived from astrocytes are known to regulate sleep, the precise mechanisms underlying the somnogenic effects of ATP and adenosine remain unclear. We selectively expressed channelrhodopsin-2 (ChR2), a light-sensitive ion channel, in astrocytes within the ventrolateral preoptic nucleus (VLPO), which is an essential brain nucleus involved in sleep promotion. We then examined the effects of photostimulation of astrocytic ChR2 on neuronal excitability using whole-cell patch-clamp recordings in two functionally distinct types of VLPO neurons: sleep-promoting GABAergic projection neurons and non-sleep-promoting local GABAergic neurons. Optogenetic stimulation of VLPO astrocytes demonstrated opposite outcomes in the two types of VLPO neurons. It led to the inhibition of non-sleep-promoting neurons and excitation of sleep-promoting neurons. These responses were attenuated by blocking of either adenosine A1 receptors or tissue-nonspecific alkaline phosphatase (TNAP). In contrast, exogenous adenosine decreased the excitability of both VLPO neuron populations. Moreover, TNAP was expressed in galanin-negative VLPO neurons, but not in galanin-positive sleep-promoting projection neurons. Taken together, these results suggest that astrocyte-derived ATP is converted into adenosine by TNAP in non-sleep-promoting neurons. In turn, adenosine decreases the excitability of local GABAergic neurons, thereby increasing the excitability of sleep-promoting GABAergic projection neurons. We propose a novel mechanism involving astrocyte-neuron interactions in sleep regulation, wherein endogenous adenosine derived from astrocytes excites sleep-promoting VLPO neurons, and thus decreases neuronal excitability in arousal-related areas of the brain.
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Affiliation(s)
- In-Sun Choi
- Department of Pharmacology, School of Dentistry, Kyungpook National University, Daegu, South Korea
| | - Jae-Hong Kim
- Department of Pharmacology, School of Medicine, Kyungpook National University, Daegu, South Korea
| | - Ji-Young Jeong
- Department of Pharmacology, School of Medicine, Kyungpook National University, Daegu, South Korea
| | - Maan-Gee Lee
- Department of Pharmacology, School of Medicine, Kyungpook National University, Daegu, South Korea.,Brain Science & Engineering Institute, Kyungpook National University, Daegu, South Korea
| | - Kyoungho Suk
- Department of Pharmacology, School of Medicine, Kyungpook National University, Daegu, South Korea.,Brain Science & Engineering Institute, Kyungpook National University, Daegu, South Korea
| | - Il-Sung Jang
- Department of Pharmacology, School of Dentistry, Kyungpook National University, Daegu, South Korea.,Brain Science & Engineering Institute, Kyungpook National University, Daegu, South Korea
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De Sousa RAL. Reactive gliosis in Alzheimer's disease: a crucial role for cognitive impairment and memory loss. Metab Brain Dis 2022; 37:851-857. [PMID: 35286534 DOI: 10.1007/s11011-022-00953-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 03/08/2022] [Indexed: 01/24/2023]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder that leads to cognitive decline and memory loss. Insulin resistance in central nervous system (CNS) is a common feature in dementia. Defective insulin signaling is associated to higher levels of inflammation and to neuronal dysfunction. A reactive gliosis, a change that occurs in glial cells due to damage in CNS, seems to be one of the most important pro-inflammatory mechanisms in AD pathology. The first response to CNS injury is the migration of macrophages and microglia to the specific site of the injury. Oligodendrocytes are also recruited to to contribute with remyelination. The last component of a reactive gliosis is astrogliosis, which is the enhancement of astrocytes expression with concomitant changes in its morphology being the main cells of the glial scar. Here, we review the mechanisms by which a reactive gliosis can induce or contribute to the development and progression of AD.
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Affiliation(s)
- Ricardo Augusto Leoni De Sousa
- School of Biological Sciences and Health, Physical Education Department, Universidade Federal Dos Vales Do Jequitinhonha E Mucuri, Diamantina, Minas Gerais, Brazil.
- Multicenter Post Graduation Program in Physiological Sciences (PMPGCF), Brazilian Society of Physiology, São Paulo, Brazil.
- Neuroscience and Exercise Study Group (Grupo de Estudos em Neurociências e Exercício - GENE), Universidade Federal Dos Vales Do Jequitinhonha E Mucuri, Diamantina, Minas Gerais, Brazil.
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Satarker S, Bojja SL, Gurram PC, Mudgal J, Arora D, Nampoothiri M. Astrocytic Glutamatergic Transmission and Its Implications in Neurodegenerative Disorders. Cells 2022; 11:cells11071139. [PMID: 35406702 PMCID: PMC8997779 DOI: 10.3390/cells11071139] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 03/12/2022] [Accepted: 03/13/2022] [Indexed: 12/11/2022] Open
Abstract
Several neurodegenerative disorders involve impaired neurotransmission, and glutamatergic neurotransmission sets a prototypical example. Glutamate is a predominant excitatory neurotransmitter where the astrocytes play a pivotal role in maintaining the extracellular levels through release and uptake mechanisms. Astrocytes modulate calcium-mediated excitability and release several neurotransmitters and neuromodulators, including glutamate, and significantly modulate neurotransmission. Accumulating evidence supports the concept of excitotoxicity caused by astrocytic glutamatergic release in pathological conditions. Thus, the current review highlights different vesicular and non-vesicular mechanisms of astrocytic glutamate release and their implication in neurodegenerative diseases. As in presynaptic neurons, the vesicular release of astrocytic glutamate is also primarily meditated by calcium-mediated exocytosis. V-ATPase is crucial in the acidification and maintenance of the gradient that facilitates the vesicular storage of glutamate. Along with these, several other components, such as cystine/glutamate antiporter, hemichannels, BEST-1, TREK-1, purinergic receptors and so forth, also contribute to glutamate release under physiological and pathological conditions. Events of hampered glutamate uptake could promote inflamed astrocytes to trigger repetitive release of glutamate. This could be favorable towards the development and worsening of neurodegenerative diseases. Therefore, across neurodegenerative diseases, we review the relations between defective glutamatergic signaling and astrocytic vesicular and non-vesicular events in glutamate homeostasis. The optimum regulation of astrocytic glutamatergic transmission could pave the way for the management of these diseases and add to their therapeutic value.
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Affiliation(s)
- Sairaj Satarker
- Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal 576104, India; (S.S.); (S.L.B.); (P.C.G.); (J.M.)
| | - Sree Lalitha Bojja
- Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal 576104, India; (S.S.); (S.L.B.); (P.C.G.); (J.M.)
| | - Prasada Chowdari Gurram
- Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal 576104, India; (S.S.); (S.L.B.); (P.C.G.); (J.M.)
| | - Jayesh Mudgal
- Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal 576104, India; (S.S.); (S.L.B.); (P.C.G.); (J.M.)
| | - Devinder Arora
- Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal 576104, India; (S.S.); (S.L.B.); (P.C.G.); (J.M.)
- School of Pharmacy and Medical Sciences, Griffith University, Gold Coast, QLD 4222, Australia;
| | - Madhavan Nampoothiri
- Department of Pharmacology, Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education, Manipal 576104, India; (S.S.); (S.L.B.); (P.C.G.); (J.M.)
- Correspondence:
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Lee HHC, McGinty GE, Pearl PL, Rotenberg A. Understanding the Molecular Mechanisms of Succinic Semialdehyde Dehydrogenase Deficiency (SSADHD): Towards the Development of SSADH-Targeted Medicine. Int J Mol Sci 2022; 23:2606. [PMID: 35269750 PMCID: PMC8910003 DOI: 10.3390/ijms23052606] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/18/2022] [Accepted: 02/21/2022] [Indexed: 11/21/2022] Open
Abstract
Succinic semialdehyde dehydrogenase deficiency (SSADHD) is a rare genetic disorder caused by inefficient metabolic breakdown of the major inhibitory neurotransmitter, γ-aminobutyric acid (GABA). Pathologic brain accumulation of GABA and γ-hydroxybutyrate (GHB), a neuroactive by-product of GABA catabolism, leads to a multitude of molecular abnormalities beginning in early life, culminating in multifaceted clinical presentations including delayed psychomotor development, intellectual disability, hypotonia, and ataxia. Paradoxically, over half of patients with SSADHD also develop epilepsy and face a significant risk of sudden unexpected death in epilepsy (SUDEP). Here, we review some of the relevant molecular mechanisms through which impaired synaptic inhibition, astrocytic malfunctions and myelin defects might contribute to the complex SSADHD phenotype. We also discuss the gaps in knowledge that need to be addressed for the implementation of successful gene and enzyme replacement SSADHD therapies. We conclude with a description of a novel SSADHD mouse model that enables 'on-demand' SSADH restoration, allowing proof-of-concept studies to fine-tune SSADH restoration in preparation for eventual human trials.
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Affiliation(s)
- Henry H. C. Lee
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA 02115, USA; (G.E.M.); (A.R.)
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children’s Hospital, Boston, MA 02115, USA
| | - Gabrielle E. McGinty
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA 02115, USA; (G.E.M.); (A.R.)
| | - Phillip L. Pearl
- Division of Epilepsy & Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Boston, MA 02115, USA;
| | - Alexander Rotenberg
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Boston, MA 02115, USA; (G.E.M.); (A.R.)
- Division of Epilepsy & Clinical Neurophysiology, Department of Neurology, Boston Children’s Hospital, Boston, MA 02115, USA;
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Heffernan KS, Rahman K, Smith Y, Galvan A. Characterization of the GfaABC1D Promoter to Selectively Target Astrocytes in the Rhesus Macaque Brain. J Neurosci Methods 2022; 372:109530. [PMID: 35202614 PMCID: PMC8940704 DOI: 10.1016/j.jneumeth.2022.109530] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 02/04/2022] [Accepted: 02/14/2022] [Indexed: 10/19/2022]
Abstract
BACKGROUND The study of astrocytic functions in non-human primates (NHPs) has been hampered by the lack of genetic tools to selectively target astrocytes. Viral vectors with selective and efficient transduction of astrocytes could be a potent tool to express marker proteins, modulators, or sensors in NHP astrocytes, but the availability of thoroughly characterized astrocytic selective promoter sequences to use in these species remains extremely limited. NEW METHOD We describe the specificity and efficiency of an astrocyte-specific promoter, GfaABC1D in the brain of the rhesus macaque, with emphasis in basal ganglia regions. AAV5-pZac2.1-GfaABC1D-tdTomato was locally injected into the globus pallidus external segment (GPe) and putamen. The extent, efficiency, and specificity of transduction was analyzed with immunohistochemistry at the light and electron microscope levels. RESULTS The GfaABC1D promoter directed the expression of tdTomato in an astrocyte-specific manner in directly or indirectly targeted regions (including both segments of the globus pallidus, putamen, subthalamic nucleus and cortex). COMPARISON WITH EXISTING METHODS Due to its small size, the GfaABC1D promoter is advantageous over other previously used glial fibrillary acidic protein-based promoter sequences, facilitating its use to drive expression of various transgenes in adeno-associated viruses (AAV) or other viral vectors. CONCLUSION GfaABC1D is an efficient promoter that selectively targets astrocytes in the monkey basal ganglia and expands the viral vector toolbox to study astrocytic functions in non-human primates.
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Affiliation(s)
- Kate S Heffernan
- Division of Neuropharmacology and Neurological Disorders, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
| | - Kazi Rahman
- Division of Neuropharmacology and Neurological Disorders, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
| | - Yoland Smith
- Division of Neuropharmacology and Neurological Disorders, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA; Udall Center of Excellence for Parkinson's Disease Research, Emory University, Atlanta, GA, USA; Department of Neurology, School of Medicine, Emory University, Atlanta, GA, USA
| | - Adriana Galvan
- Division of Neuropharmacology and Neurological Disorders, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA; Udall Center of Excellence for Parkinson's Disease Research, Emory University, Atlanta, GA, USA; Department of Neurology, School of Medicine, Emory University, Atlanta, GA, USA.
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38
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Miguel-Hidalgo JJ. Astroglia in the Vulnerability and Maintenance of Alcohol Use Disorders. ADVANCES IN NEUROBIOLOGY 2021; 26:255-279. [PMID: 34888838 DOI: 10.1007/978-3-030-77375-5_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Changes induced in the morphology and the multiplicity of functional roles played by astrocytes in brain regions critical to the establishment and maintenance of alcohol abuse suggest that they make an important contribution to the vulnerability to alcohol use disorders. The understanding of the relevant mechanisms accounting for that contribution is complicated by the fact that alcohol itself acts directly on astrocytes altering their metabolism, gene expression, and plasticity, so that the ultimate result is a complex interaction of various cellular pathways, including intracellular calcium regulation, neuroimmune responses, and regulation of neurotransmitter and gliotransmitter release and uptake. The recent years have seen a steady increase in the characterization of several of the relevant mechanisms, but much remains to be done for a full understanding of the astrocytes' contribution to the vulnerability to alcohol dependence and abuse and for using that knowledge in designing effective therapies for AUDs.
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Affiliation(s)
- José Javier Miguel-Hidalgo
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, USA.
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Muñoz MF, Griffith TN, Contreras JE. Mechanisms of ATP release in pain: role of pannexin and connexin channels. Purinergic Signal 2021; 17:549-561. [PMID: 34792743 PMCID: PMC8677853 DOI: 10.1007/s11302-021-09822-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 10/18/2021] [Indexed: 12/21/2022] Open
Abstract
Pain is a physiological response to bodily damage and serves as a warning of potential threat. Pain can also transform from an acute response to noxious stimuli to a chronic condition with notable emotional and psychological components that requires treatment. Indeed, the management of chronic pain is currently an important unmet societal need. Several reports have implicated the release of the neurotransmitter adenosine triphosphate (ATP) and subsequent activation of purinergic receptors in distinct pain etiologies. Purinergic receptors are broadly expressed in peripheral neurons and the spinal cord; thus, purinergic signaling in sensory neurons or in spinal circuits may be critical for pain processing. Nevertheless, an outstanding question remains: what are the mechanisms of ATP release that initiate nociceptive signaling? Connexin and pannexin channels are established conduits of ATP release and have been suggested to play important roles in a variety of pathologies, including several models of pain. As such, these large-pore channels represent a new and exciting putative pharmacological target for pain treatment. Herein, we will review the current evidence for a role of connexin and pannexin channels in ATP release during nociceptive signaling, such as neuropathic and inflammatory pain. Collectively, these studies provide compelling evidence for an important role of connexins and pannexins in pain processing.
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Affiliation(s)
- Manuel F. Muñoz
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, USA
| | - Theanne N. Griffith
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, USA
| | - Jorge E. Contreras
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, USA
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González-Casanova JE, Durán-Agüero S, Caro-Fuentes NJ, Gamboa-Arancibia ME, Bruna T, Bermúdez V, Rojas-Gómez DM. New Insights on the Role of Connexins and Gap Junctions Channels in Adipose Tissue and Obesity. Int J Mol Sci 2021; 22:ijms222212145. [PMID: 34830025 PMCID: PMC8619175 DOI: 10.3390/ijms222212145] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 11/05/2021] [Accepted: 11/05/2021] [Indexed: 12/20/2022] Open
Abstract
Due to the inability to curb the excessive increase in the prevalence of obesity and overweight, it is necessary to comprehend in more detail the factors involved in the pathophysiology and to appreciate more clearly the biochemical and molecular mechanisms of obesity. Thus, understanding the biological regulation of adipose tissue is of fundamental relevance. Connexin, a protein that forms intercellular membrane channels of gap junctions and unopposed hemichannels, plays a key role in adipogenesis and in the maintenance of adipose tissue homeostasis. The expression and function of Connexin 43 (Cx43) during the different stages of the adipogenesis are differentially regulated. Moreover, it has been shown that cell–cell communication decreases dramatically upon differentiation into adipocytes. Furthermore, inhibition of Cx43 degradation or constitutive overexpression of Cx43 blocks adipocyte differentiation. In the first events of adipogenesis, the connexin is highly phosphorylated, which is likely associated with enhanced Gap Junction (GJ) communication. In an intermediate state of adipocyte differentiation, Cx43 phosphorylation decreases, as it is displaced from the membrane and degraded through the proteasome; thus, Cx43 total protein is reduced. Cx is involved in cardiac disease as well as in obesity-related cardiovascular diseases. Different studies suggest that obesity together with a high-fat diet are related to the production of remodeling factors associated with expression and distribution of Cx43 in the atrium.
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Affiliation(s)
- Jorge Enrique González-Casanova
- Facultad de Ciencias de la Salud, Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago 8910060, Chile; (J.E.G.-C.); (N.J.C.-F.)
| | - Samuel Durán-Agüero
- Facultad de Ciencias Para el Cuidado de la Salud, Universidad San Sebastián, Sede Los Leones, Lota 2465, Providencia, Santiago 7500000, Chile;
| | - Nelson Javier Caro-Fuentes
- Facultad de Ciencias de la Salud, Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago 8910060, Chile; (J.E.G.-C.); (N.J.C.-F.)
| | - Maria Elena Gamboa-Arancibia
- Facultad de Química y Biología, Universidad de Santiago de Chile, Av. Libertador Bernardo O’higgins 3363, Estación Central, Santiago 9170022, Chile;
| | - Tamara Bruna
- Centro de Investigación Austral Biotech, Facultad de Ciencias, Universidad Santo Tomás, Avenida Ejercito 146, Santiago 8320000, Chile;
| | - Valmore Bermúdez
- Facultad de Ciencias de la Salud, Universidad Simón Bolívar, Barranquilla 080002, Colombia;
| | - Diana Marcela Rojas-Gómez
- Escuela de Nutrición y Dietética, Facultad de Medicina, Universidad Andres Bello, Santiago 8370321, Chile
- Correspondence: ; Tel.: +56-226618559
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Ahluwalia M, Kumar M, Ahluwalia P, Rahimi S, Vender JR, Raju RP, Hess DC, Baban B, Vale FL, Dhandapani KM, Vaibhav K. Rescuing mitochondria in traumatic brain injury and intracerebral hemorrhages - A potential therapeutic approach. Neurochem Int 2021; 150:105192. [PMID: 34560175 PMCID: PMC8542401 DOI: 10.1016/j.neuint.2021.105192] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 09/18/2021] [Accepted: 09/20/2021] [Indexed: 02/07/2023]
Abstract
Mitochondria are dynamic organelles responsible for cellular energy production. Besides, regulating energy homeostasis, mitochondria are responsible for calcium homeostasis, signal transmission, and the fate of cellular survival in case of injury and pathologies. Accumulating reports have suggested multiple roles of mitochondria in neuropathologies, neurodegeneration, and immune activation under physiological and pathological conditions. Mitochondrial dysfunction, which occurs at the initial phase of brain injury, involves oxidative stress, inflammation, deficits in mitochondrial bioenergetics, biogenesis, transport, and autophagy. Thus, development of targeted therapeutics to protect mitochondria may improve functional outcomes following traumatic brain injury (TBI) and intracerebral hemorrhages (ICH). In this review, we summarize mitochondrial dysfunction related to TBI and ICH, including the mechanisms involved, and discuss therapeutic approaches with special emphasis on past and current clinical trials.
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Affiliation(s)
- Meenakshi Ahluwalia
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, USA.
| | - Manish Kumar
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Pankaj Ahluwalia
- Department of Pathology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Scott Rahimi
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - John R Vender
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Raghavan P Raju
- Department of Pharmacology and Toxicology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - David C Hess
- Department of Neurology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Babak Baban
- Department of Oral Biology and Diagnostic Sciences, Dental College of Georgia, Augusta University, Augusta, GA, USA
| | - Fernando L Vale
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Krishnan M Dhandapani
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Kumar Vaibhav
- Department of Neurosurgery, Medical College of Georgia, Augusta University, Augusta, GA, USA; Department of Oral Biology and Diagnostic Sciences, Dental College of Georgia, Augusta University, Augusta, GA, USA.
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Effects of an Atypical Antipsychotic, Zotepine, on Astroglial L-Glutamate Release through Hemichannels: Exploring the Mechanism of Mood-Stabilising Antipsychotic Actions and Antipsychotic-Induced Convulsion. Pharmaceuticals (Basel) 2021; 14:ph14111116. [PMID: 34832898 PMCID: PMC8625878 DOI: 10.3390/ph14111116] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Revised: 10/28/2021] [Accepted: 10/28/2021] [Indexed: 02/06/2023] Open
Abstract
Accumulating neuropsychopharmacological evidence has suggested that functional abnormalities of astroglial transmission and protein kinase B (Akt) contribute to the pathophysiology and/or pathomechanisms of several neuropsychiatric disorders, such as epilepsy, schizophrenia, affective disorders and antipsychotic-induced convulsions. Therefore, to explore the pathophysiology of mood-stabilising antipsychotics and the proconvulsive actions of atypical antipsychotics, the present study determined the effects of a mood-stabilising, atypical, antipsychotic agent, zotepine (ZTP), on astroglial L-glutamate release and the expression of connexin43 (Cx43) protein in cortical, primary, cultured astrocytes using ultra-high-pressure liquid chromatography and capillary immunoblotting systems. Both acute and subchronic administrations of therapeutically relevant concentrations of ZTP did not affect astroglial L-glutamate release or Cx43 expression in plasma membranes; however, chronic administration of a therapeutically relevant concentration of ZTP increased astroglial L-glutamate release and Cx43 expression in the plasma membrane. Subchronic administrations of a supratherapeutic concentration of ZTP enhanced astroglial L-glutamate release and Cx43 expression in the plasma membrane, whereas acute administration of a supratherapeutic concentration of ZTP enhanced astroglial L-glutamate release without affecting Cx43 expression. These stimulatory effects of ZTP on astroglial L-glutamate release through activated hemichannels and Cx43 trafficking to the astroglial plasma membrane were suppressed by the Akt inhibitor. These results suggest that ZTP enhances astroglial L-glutamate release in a concentration-dependent and time-dependent manner due to the enhanced function of astroglial hemichannels, probably via activation of Akt signalling. Therefore, the enhanced astroglial L-glutamatergic transmission induced by ZTP is, at least partially, involved in the mood-stabilising antipsychotic and proconvulsive actions of ZTP.
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Distinct Effects of Escitalopram and Vortioxetine on Astroglial L-Glutamate Release Associated with Connexin43. Int J Mol Sci 2021; 22:ijms221810013. [PMID: 34576176 PMCID: PMC8468507 DOI: 10.3390/ijms221810013] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 09/10/2021] [Accepted: 09/14/2021] [Indexed: 12/20/2022] Open
Abstract
It has been established that enhancement of serotonergic transmission contributes to improvement of major depression; however, several post-mortem studies and experimental depression rodent models suggest that functional abnormalities of astrocytes play important roles in the pathomechanisms/pathophysiology of mood disorders. Direct effects of serotonin (5-HT) transporter inhibiting antidepressants on astroglial transmission systems has never been assessed in this context. Therefore, to explore the effects of antidepressants on transmission associated with astrocytes, the present study determined the effects of the selective 5-HT transporter inhibitor, escitalopram, and the 5-HT partial agonist reuptake inhibitor, vortioxetine, on astroglial L-glutamate release through activated hemichannels, and the expression of connexin43 (Cx43), type 1A (5-HT1AR) and type 7 (5-HT7R) 5-HT receptor subtypes, and extracellular signal-regulated kinase (ERK) in astrocytes using primary cultured rat cortical astrocytes in a 5-HT-free environment. Both escitalopram and 5-HT1AR antagonist (WAY100635) did not affect basal astroglial L-glutamate release or L-glutamate release through activated hemichannels. Subchronic (for seven days) administrations of vortioxetine and the 5-HT7R inverse agonist (SB269970) suppressed both basal L-glutamate release and L-glutamate release through activated hemichannels, whereas 5-HT1AR agonist (BP554) inhibited L-glutamate release through activated hemichannels, but did not affect basal L-glutamate release. In particular, WAY100635 did not affect the inhibitory effects of vortioxetine on L-glutamate release. Subchronic administration of vortioxetine, BP554 and SB269970 downregulated 5-HT1AR, 5-HT7R and phosphorylated ERK in the plasma membrane fraction, but escitalopram and WAY100635 did not affect them. Subchronic administration of SB269970 decreased Cx43 expression in the plasma membrane but did not affect the cytosol; however, subchronic administration of BP554 increased Cx43 expression in the cytosol but did not affect the plasma membrane. Subchronic vortioxetine administration increased Cx43 expression in the cytosol and decreased it in the plasma membrane. WAY100635 prevented an increased Cx43 expression in the cytosol induced by vortioxetine without affecting the reduced Cx43 expression in the plasma membrane. These results suggest that 5-HT1AR downregulation probably increases Cx43 synthesis, but 5-HT7R downregulation suppresses Cx43 trafficking to the plasma membrane. These results also suggest that the subchronic administration of therapeutic-relevant concentrations of vortioxetine inhibits both astroglial L-glutamate and Cx43 expression in the plasma membrane via 5-HT7R downregulation but enhances Cx43 synthesis in the cytosol via 5-HT1AR downregulation. This combination of the downregulation of 5-HT1AR, 5-HT7R and Cx43 in the astroglial plasma membrane induced by subchronic vortioxetine administration suggest that astrocytes is possibly involved in the pathophysiology of depression.
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Jindal S, Chockalingam S, Ghosh SS, Packirisamy G. Connexin and gap junctions: perspectives from biology to nanotechnology based therapeutics. Transl Res 2021; 235:144-167. [PMID: 33582245 DOI: 10.1016/j.trsl.2021.02.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 01/10/2021] [Accepted: 02/09/2021] [Indexed: 12/11/2022]
Abstract
The concept of gap junctions and their role in intercellular communication has been known for around 50 years. Considerable progress has been made in understanding the fundamental biology of connexins in mediating gap junction intercellular communication (GJIC) and their role in various cellular processes including pathological conditions. However, this understanding has not led to development of advanced therapeutics utilizing GJIC. Inadequacies in strategies that target specific connexin protein in the affected tissue, with minimal or no collateral damage, are the primary reason for the lack of development of efficient therapeutic models. Herein, nanotechnology has a role to play, giving plenty of scope to circumvent these problems and develop more efficient connexin based therapeutics. AsODN, antisense oligodeoxynucleotides; BMPs, bone morphogenetic proteins; BMSCs, bone marrow stem cells; BG, bioglass; Cx, Connexin; CxRE, connexin-responsive elements; CoCr NPs, cobalt-chromium nanoparticles; cGAMP, cyclic guanosine monophosphate-adenosine monophosphate; cAMP, cyclic adenosine monophosphate; ERK1/2, extracellular signal-regulated kinase 1/2; EMT, epithelial-mesenchymal transition; EPA, eicosapentaenoic acids; FGFR1, fibroblast growth factor receptor 1; FRAP, fluorescence recovery after photobleaching; 5-FU, 5-fluorouracil; GJ, gap junction; GJIC, gap junctional intercellular communication; HGPRTase, hypoxanthine phosphoribosyltransferase; HSV-TK, herpes virus thymidine kinase; HSA, human serum albumin; HA, hyaluronic acid; HDAC, histone deacetylase; IRI, ischemia reperfusion injury; IL-6, interleukin-6; IL-8, interleukin-8; IONPs, iron-oxide nanoparticles; JNK, c-Jun N-terminal kinase; LAMP, local activation of molecular fluorescent probe; MSCs, mesenchymal stem cells; MMP, matrix metalloproteinase; MI, myocardial infarction; MAPK, mitogen-activated protein kinase; NF-κB, nuclear factor kappa B; NO, nitric oxide; PKC, protein kinase C; QDs, quantum dots; ROI, region of interest; RGO, reduced graphene oxide; siRNA, small interfering RNA; TGF-β1, transforming growth factor-β1; TNF-α, tumor necrosis factor-α; UCN, upconversion nanoparticles; VEGF, vascular endothelial growth factor. In this review, we discuss briefly the role of connexins and gap junctions in various physiological and pathological processes, with special emphasis on cancer. We further discuss the application of nanotechnology and tissue engineering in developing treatments for various connexin based disorders.
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Affiliation(s)
- Shlok Jindal
- Nanobiotechnology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, India
| | - S Chockalingam
- Department of Biotechnology, National Institute of Technology Warangal, Warangal, Telangana, India
| | - Siddhartha Sankar Ghosh
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India
| | - Gopinath Packirisamy
- Nanobiotechnology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, India; Centre for Nanotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, India.
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Bastos PAD, Wheeler R, Boneca IG. Uptake, recognition and responses to peptidoglycan in the mammalian host. FEMS Microbiol Rev 2021; 45:5902851. [PMID: 32897324 PMCID: PMC7794044 DOI: 10.1093/femsre/fuaa044] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 09/03/2020] [Indexed: 12/13/2022] Open
Abstract
Microbiota, and the plethora of signalling molecules that they generate, are a major driving force that underlies a striking range of inter-individual physioanatomic and behavioural consequences for the host organism. Among the bacterial effectors, one finds peptidoglycan, the major constituent of the bacterial cell surface. In the steady-state, fragments of peptidoglycan are constitutively liberated from bacterial members of the gut microbiota, cross the gut epithelial barrier and enter the host system. The fate of these peptidoglycan fragments, and the outcome for the host, depends on the molecular nature of the peptidoglycan, as well the cellular profile of the recipient tissue, mechanism of cell entry, the expression of specific processing and recognition mechanisms by the cell, and the local immune context. At the target level, physiological processes modulated by peptidoglycan are extremely diverse, ranging from immune activation to small molecule metabolism, autophagy and apoptosis. In this review, we bring together a fragmented body of literature on the kinetics and dynamics of peptidoglycan interactions with the mammalian host, explaining how peptidoglycan functions as a signalling molecule in the host under physiological conditions, how it disseminates within the host, and the cellular responses to peptidoglycan.
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Affiliation(s)
- Paulo A D Bastos
- Institut Pasteur, Biology and genetics of the bacterial cell wall Unit, 25-28 rue du Docteur Roux, Paris 75724, France; CNRS, UMR 2001 "Microbiologie intégrative et moléculaire", Paris 75015, France.,Université de Paris, Sorbonne Paris Cité, 12 rue de l'Ecole de Médecine, 75006, Paris, France
| | - Richard Wheeler
- Institut Pasteur, Biology and genetics of the bacterial cell wall Unit, 25-28 rue du Docteur Roux, Paris 75724, France; CNRS, UMR 2001 "Microbiologie intégrative et moléculaire", Paris 75015, France.,Tumour Immunology and Immunotherapy, Institut Gustave Roussy, 114 rue Edouard-Vaillant, Villejuif 94800, France; INSERM UMR 1015, Villejuif 94800, France
| | - Ivo G Boneca
- Institut Pasteur, Biology and genetics of the bacterial cell wall Unit, 25-28 rue du Docteur Roux, Paris 75724, France; CNRS, UMR 2001 "Microbiologie intégrative et moléculaire", Paris 75015, France
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Harnessing the therapeutic potential of antibodies targeting connexin hemichannels. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166047. [PMID: 33418036 DOI: 10.1016/j.bbadis.2020.166047] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 11/17/2020] [Accepted: 12/03/2020] [Indexed: 12/20/2022]
Abstract
BACKGROUND Connexin hemichannels have been implicated in pathology-promoting conditions, including inflammation, numerous widespread human diseases, including cancer and diabetes, and several rare diseases linked to pathological point mutations. METHODS We analysed the literature focusing on antibodies capable of modulating hemichannel function, highlighting generation methods, applications to basic biomedical research and translational potential. RESULTS Anti-hemichannel antibodies generated over the past 3 decades targeted mostly connexin 43, with a focus on cancer treatment. A slow transition from relatively unselective polyclonal antibodies to more selective monoclonal antibodies resulted in few products with interesting characteristics that are under evaluation for clinical trials. Selection of antibodies from combinatorial phage-display libraries, has permitted to engineer a monoclonal antibody that binds to and blocks pathological hemichannels formed by connexin 26, 30 and 32. CONCLUSIONS All known antibodies that modulate connexin hemichannels target the two small extracellular loops of the connexin proteins. The extracellular region of different connexins is highly conserved, and few residues of each connexins are exposed. The search for new antibodies may develop an unprecedented potential for therapeutic applications, as it may benefit tremendously from novel whole-cell screening platforms that permit in situ selection of antibodies against membrane proteins in native state. The demonstrated efficacy of mAbs in reaching and modulating hemichannels in vivo, together with their relative specificity for connexins overlapping epitopes, should hopefully stimulate an interest for widening the scope of anti-hemichannel antibodies. There is no shortage of currently incurable diseases for which therapeutic intervention may benefit from anti-hemichannel antibodies capable of modulating hemichannel function selectively and specifically.
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Astroglial Connexin43 as a Potential Target for a Mood Stabiliser. Int J Mol Sci 2020; 22:ijms22010339. [PMID: 33396966 PMCID: PMC7795839 DOI: 10.3390/ijms22010339] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 12/24/2020] [Accepted: 12/27/2020] [Indexed: 02/06/2023] Open
Abstract
Mood disorders remain a major public health concern worldwide. Monoaminergic hypotheses of pathophysiology of bipolar and major depressive disorders have led to the development of monoamine transporter-inhibiting antidepressants for the treatment of major depression and have contributed to the expanded indications of atypical antipsychotics for the treatment of bipolar disorders. In spite of psychopharmacological progress, current pharmacotherapy according to the monoaminergic hypothesis alone is insufficient to improve or prevent mood disorders. Recent approval of esketamine for treatment of treatment-resistant depression has attracted attention in psychopharmacology as a glutamatergic hypothesis of the pathophysiology of mood disorders. On the other hand, in the last decade, accumulated findings regarding the pathomechanisms of mood disorders emphasised that functional abnormalities of tripartite synaptic transmission play important roles in the pathophysiology of mood disorders. At first glance, the enhancement of astroglial connexin seems to contribute to antidepressant and mood-stabilising effects, but in reality, antidepressive and mood-stabilising actions are mediated by more complicated interactions associated with the astroglial gap junction and hemichannel. Indeed, several depressive mood-inducing stress stimulations suppress connexin43 expression and astroglial gap junction function, but enhance astroglial hemichannel activity. On the other hand, monoamine transporter-inhibiting antidepressants suppress astroglial hemichannel activity and enhance astroglial gap junction function, whereas several non-antidepressant mood stabilisers activate astroglial hemichannel activity. Based on preclinical findings, in this review, we summarise the effects of antidepressants, mood-stabilising antipsychotics, and anticonvulsants on astroglial connexin, and then, to establish a novel strategy for treatment of mood disorders, we reveal the current progress in psychopharmacology, changing the question from "what has been revealed?" to "what should be clarified?".
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Astrocytes in the Ventrolateral Preoptic Area Promote Sleep. J Neurosci 2020; 40:8994-9011. [PMID: 33067363 DOI: 10.1523/jneurosci.1486-20.2020] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 10/05/2020] [Accepted: 10/13/2020] [Indexed: 11/21/2022] Open
Abstract
Although ventrolateral preoptic (VLPO) nucleus is regarded as a center for sleep promotion, the exact mechanisms underlying the sleep regulation are unknown. Here, we used optogenetic tools to identify the key roles of VLPO astrocytes in sleep promotion. Optogenetic stimulation of VLPO astrocytes increased sleep duration in the active phase in naturally sleep-waking adult male rats (n = 6); it also increased the extracellular ATP concentration (n = 3) and c-Fos expression (n = 3-4) in neurons within the VLPO. In vivo microdialysis analyses revealed an increase in the activity of VLPO astrocytes and ATP levels during sleep states (n = 4). Moreover, metabolic inhibition of VLPO astrocytes reduced ATP levels (n = 4) and diminished sleep duration (n = 4). We further show that tissue-nonspecific alkaline phosphatase (TNAP), an ATP-degrading enzyme, plays a key role in mediating the somnogenic effects of ATP released from astrocytes (n = 5). An appropriate sample size for all experiments was based on statistical power calculations. Our results, taken together, indicate that astrocyte-derived ATP may be hydrolyzed into adenosine by TNAP, which may in turn act on VLPO neurons to promote sleep.SIGNIFICANCE STATEMENT Glia have recently been at the forefront of neuroscience research. Emerging evidence illustrates that astrocytes, the most abundant glial cell type, are the functional determinants for fates of neurons and other glial cells in the central nervous system. In this study, we newly identified the pivotal role of hypothalamic ventrolateral preoptic (VLPO) astrocytes in the sleep regulation, and provide novel insights into the mechanisms underlying the astrocyte-mediated sleep regulation.
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Abou-Mrad Z, Alomari SO, Bsat S, Moussalem CK, Alok K, El Houshiemy MN, Alomari AO, Minassian GB, Omeis IA. Role of connexins in spinal cord injury: An update. Clin Neurol Neurosurg 2020; 197:106102. [DOI: 10.1016/j.clineuro.2020.106102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 07/16/2020] [Accepted: 07/18/2020] [Indexed: 01/25/2023]
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Lee HJ, Jeong H, Hyun J, Ryu B, Park K, Lim HH, Yoo J, Woo JS. Cryo-EM structure of human Cx31.3/GJC3 connexin hemichannel. SCIENCE ADVANCES 2020; 6:eaba4996. [PMID: 32923625 PMCID: PMC7455182 DOI: 10.1126/sciadv.aba4996] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 07/15/2020] [Indexed: 05/28/2023]
Abstract
Connexin family proteins assemble into hexameric channels called hemichannels/connexons, which function as transmembrane channels or dock together to form gap junction intercellular channels (GJIChs). We determined the cryo-electron microscopy structures of human connexin 31.3 (Cx31.3)/GJC3 hemichannels in the presence and absence of calcium ions and with a hearing-loss mutation R15G at 2.3-, 2.5-, and 2.6-Å resolutions, respectively. Compared with available structures of GJICh in open conformation, Cx31.3 hemichannel shows substantial structural changes of highly conserved regions in the connexin family, including opening of calcium ion-binding tunnels, reorganization of salt-bridge networks, exposure of lipid-binding sites, and collocation of amino-terminal helices at the cytoplasmic entrance. We also found that the hemichannel has a pore with a diameter of ~8 Å and selectively transports chloride ions. Our study provides structural insights into the permeant selectivity of Cx31.3 hemichannel.
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Affiliation(s)
- Hyuk-Joon Lee
- Department of Life Sciences, Korea University, Seoul 02841, Republic of Korea
| | - Hyeongseop Jeong
- Department of Life Sciences, Korea University, Seoul 02841, Republic of Korea
- Korea Basic Science Institute, Chungcheongbuk-do 28119, Republic of Korea
| | - Jaekyung Hyun
- Korea Basic Science Institute, Chungcheongbuk-do 28119, Republic of Korea
- Molecular Cryo-electron Microscopy Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa 904-0496, Japan
| | - Bumhan Ryu
- Department of Life Sciences, Korea University, Seoul 02841, Republic of Korea
| | - Kunwoong Park
- Neurovascular Unit Research Group, Korea Brain Research Institute (KBRI), 41062 Daegu, Republic of Korea
| | - Hyun-Ho Lim
- Neurovascular Unit Research Group, Korea Brain Research Institute (KBRI), 41062 Daegu, Republic of Korea
| | - Jejoong Yoo
- Department of Physics, Sungkyunkwan University, Suwon, Republic of Korea
- Center for Self-assembly and Complexity (CSC), Institute for Basic Science (IBS), Pohang 37673, Republic of Korea
| | - Jae-Sung Woo
- Department of Life Sciences, Korea University, Seoul 02841, Republic of Korea
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