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Gargiulo MR, Argibay LM, Molina VA, Calfa GD, Bender CL. Role of amygdala astrocytes in different phases of contextual fear memory. Behav Brain Res 2024; 468:115017. [PMID: 38679145 DOI: 10.1016/j.bbr.2024.115017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 04/23/2024] [Accepted: 04/23/2024] [Indexed: 05/01/2024]
Abstract
Growing evidence indicates a critical role of astrocytes in learning and memory. However, little is known about the role of basolateral amygdala complex (BLA-C) astrocytes in contextual fear conditioning (CFC), a paradigm relevant to understand and generate treatments for fear- and anxiety-related disorders. To get insights on the involvement of BLA-C astrocytes in fear memory, fluorocitrate (FLC), a reversible astroglial metabolic inhibitor, was applied at critical moments of the memory processing in order to target the acquisition, consolidation, retrieval and reconsolidation process of the fear memory. Adult Wistar male rats were bilaterally cannulated in BLA-C. Ten days later they were infused with different doses of FLC (0.5 or 1 nmol/0.5 µl) or saline before or after CFC and before or after retrieval. FLC impaired fear memory expression when administered before and shortly after CFC, but not one hour later. Infusion of FLC prior and after retrieval did not affect the memory. Our findings suggest that BLA-C astrocytes are critically involved in the acquisition/early consolidation of fear memory but not in the retrieval and reconsolidation. Furthermore, the extinction process was presumably not affected (considering that peri-retrieval administration could also affect this process).
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Affiliation(s)
- Melisa Riva Gargiulo
- Instituto de Farmacología Experimental de Córdoba (IFEC-CONICET) - Departamento de Farmacología Otto Orsingher (FCQ-UNC), Córdoba, Argentina
| | - Lourdes María Argibay
- Instituto de Farmacología Experimental de Córdoba (IFEC-CONICET) - Departamento de Farmacología Otto Orsingher (FCQ-UNC), Córdoba, Argentina
| | - Víctor Alejandro Molina
- Instituto de Farmacología Experimental de Córdoba (IFEC-CONICET) - Departamento de Farmacología Otto Orsingher (FCQ-UNC), Córdoba, Argentina
| | - Gastón Diego Calfa
- Instituto de Farmacología Experimental de Córdoba (IFEC-CONICET) - Departamento de Farmacología Otto Orsingher (FCQ-UNC), Córdoba, Argentina
| | - Crhistian Luis Bender
- Instituto de Farmacología Experimental de Córdoba (IFEC-CONICET) - Departamento de Farmacología Otto Orsingher (FCQ-UNC), Córdoba, Argentina.
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2
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Tichauer JE, Lira M, Cerpa W, Orellana JA, Sáez JC, Rovegno M. Inhibition of astroglial hemichannels prevents synaptic transmission decline during spreading depression. Biol Res 2024; 57:39. [PMID: 38867288 PMCID: PMC11167948 DOI: 10.1186/s40659-024-00519-9] [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: 04/01/2024] [Accepted: 05/28/2024] [Indexed: 06/14/2024] Open
Abstract
BACKGROUND Spreading depression (SD) is an intriguing phenomenon characterized by massive slow brain depolarizations that affect neurons and glial cells. This phenomenon is repetitive and produces a metabolic overload that increases secondary damage. However, the mechanisms associated with the initiation and propagation of SD are unknown. Multiple lines of evidence indicate that persistent and uncontrolled opening of hemichannels could participate in the pathogenesis and progression of several neurological disorders including acute brain injuries. Here, we explored the contribution of astroglial hemichannels composed of connexin-43 (Cx43) or pannexin-1 (Panx1) to SD evoked by high-K+ stimulation in brain slices. RESULTS Focal high-K+ stimulation rapidly evoked a wave of SD linked to increased activity of the Cx43 and Panx1 hemichannels in the brain cortex, as measured by light transmittance and dye uptake analysis, respectively. The activation of these channels occurs mainly in astrocytes but also in neurons. More importantly, the inhibition of both the Cx43 and Panx1 hemichannels completely prevented high K+-induced SD in the brain cortex. Electrophysiological recordings also revealed that Cx43 and Panx1 hemichannels critically contribute to the SD-induced decrease in synaptic transmission in the brain cortex and hippocampus. CONCLUSIONS Targeting Cx43 and Panx1 hemichannels could serve as a new therapeutic strategy to prevent the initiation and propagation of SD in several acute brain injuries.
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Affiliation(s)
- Juan E Tichauer
- Departamento de Medicina Intensiva, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Matías Lira
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Waldo Cerpa
- Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan A Orellana
- Departamento de Neurología, Escuela de Medicina, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.
- Centro Interdisciplinario de Neurociencias, Pontificia Universidad Católica de Chile, Santiago, Chile.
| | - Juan C Sáez
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.
- Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile.
| | - Maximiliano Rovegno
- Departamento de Medicina Intensiva, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.
- Centro Interdisciplinario de Neurociencias, Pontificia Universidad Católica de Chile, Santiago, Chile.
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3
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Gómez GI, Alvear TF, Roa DA, Farias-Pasten A, Vergara SA, Mellado LA, Martinez-Araya CJ, Prieto-Villalobos J, García-Rodríguez C, Sánchez N, Sáez JC, Ortíz FC, Orellana JA. Cx43 hemichannels and panx1 channels contribute to ethanol-induced astrocyte dysfunction and damage. Biol Res 2024; 57:15. [PMID: 38576018 PMCID: PMC10996276 DOI: 10.1186/s40659-024-00493-2] [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: 12/23/2023] [Accepted: 03/25/2024] [Indexed: 04/06/2024] Open
Abstract
BACKGROUND Alcohol, a widely abused drug, significantly diminishes life quality, causing chronic diseases and psychiatric issues, with severe health, societal, and economic repercussions. Previously, we demonstrated that non-voluntary alcohol consumption increases the opening of Cx43 hemichannels and Panx1 channels in astrocytes from adolescent rats. However, whether ethanol directly affects astroglial hemichannels and, if so, how this impacts the function and survival of astrocytes remains to be elucidated. RESULTS Clinically relevant concentrations of ethanol boost the opening of Cx43 hemichannels and Panx1 channels in mouse cortical astrocytes, resulting in the release of ATP and glutamate. The activation of these large-pore channels is dependent on Toll-like receptor 4, P2X7 receptors, IL-1β and TNF-α signaling, p38 mitogen-activated protein kinase, and inducible nitric oxide (NO) synthase. Notably, the ethanol-induced opening of Cx43 hemichannels and Panx1 channels leads to alterations in cytokine secretion, NO production, gliotransmitter release, and astrocyte reactivity, ultimately impacting survival. CONCLUSION Our study reveals a new mechanism by which ethanol impairs astrocyte function, involving the sequential stimulation of inflammatory pathways that further increase the opening of Cx43 hemichannels and Panx1 channels. We hypothesize that targeting astroglial hemichannels could be a promising pharmacological approach to preserve astrocyte function and synaptic plasticity during the progression of various alcohol use disorders.
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Affiliation(s)
- Gonzalo I Gómez
- Institute of Biomedical Sciences, Faculty of Health Sciences, Universidad Autónoma de Chile, Santiago, Chile
| | - Tanhia F Alvear
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, 8330024, Chile
| | - Daniela A Roa
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, 8330024, Chile
| | - Arantza Farias-Pasten
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, 8330024, Chile
| | - Sergio A Vergara
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, 8330024, Chile
| | - Luis A Mellado
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, 8330024, Chile
| | - Claudio J Martinez-Araya
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, 8330024, Chile
| | - Juan Prieto-Villalobos
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, 8330024, Chile
| | - Claudia García-Rodríguez
- Instituto de Neurociencia, Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, 2360102, Chile
| | - Natalia Sánchez
- Department of Anatomy, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan C Sáez
- Instituto de Neurociencia, Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, 2360102, Chile
| | - Fernando C Ortíz
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Mechanisms of Myelin Formation and Repair Laboratory, Chacabuco 675, of. 212, Santiago, 8350347, Chile.
| | - Juan A Orellana
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, 8330024, Chile.
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4
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Adermark L, Stomberg R, Söderpalm B, Ericson M. Astrocytic Regulation of Endocannabinoid-Dependent Synaptic Plasticity in the Dorsolateral Striatum. Int J Mol Sci 2024; 25:581. [PMID: 38203752 PMCID: PMC10779090 DOI: 10.3390/ijms25010581] [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: 11/29/2023] [Revised: 12/26/2023] [Accepted: 12/28/2023] [Indexed: 01/12/2024] Open
Abstract
Astrocytes are pivotal for synaptic transmission and may also play a role in the induction and expression of synaptic plasticity, including endocannabinoid-mediated long-term depression (eCB-LTD). In the dorsolateral striatum (DLS), eCB signaling plays a major role in balancing excitation and inhibition and promoting habitual learning. The aim of this study was to outline the role of astrocytes in regulating eCB signaling in the DLS. To this end, we employed electrophysiological slice recordings combined with metabolic, chemogenetic and pharmacological approaches in an attempt to selectively suppress astrocyte function. High-frequency stimulation induced eCB-mediated LTD (HFS-LTD) in brain slices from both male and female rats. The metabolic uncoupler fluorocitrate (FC) reduced the probability of transmitter release and depressed synaptic output in a manner that was independent on cannabinoid 1 receptor (CB1R) activation. Fluorocitrate did not affect the LTD induced by the CB1R agonist WIN55,212-2, but enhanced CB1R-dependent HFS-LTD. Reduced neurotransmission and facilitated HFS-LTD were also observed during chemogenetic manipulation using Gi-coupled DREADDs targeting glial fibrillary acidic protein (GFAP)-expressing cells, during the pharmacological inhibition of connexins using carbenoxolone disodium, or during astrocytic glutamate uptake using TFB-TBOA. While pretreatment with the N-methyl-D-aspartate (NMDA) receptor antagonist 2-amino-5-phosphonopentanoic acid (APV) failed to prevent synaptic depression induced by FC, it blocked the facilitation of HFS-LTD. While the lack of tools to disentangle astrocytes from neurons is a major limitation of this study, our data collectively support a role for astrocytes in modulating basal neurotransmission and eCB-mediated synaptic plasticity.
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Affiliation(s)
- Louise Adermark
- Department of Pharmacology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, 40530 Gothenburg, Sweden
| | - Rosita Stomberg
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, 40530 Gothenburg, Sweden; (R.S.); (B.S.); (M.E.)
| | - Bo Söderpalm
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, 40530 Gothenburg, Sweden; (R.S.); (B.S.); (M.E.)
- Beroendekliniken, Sahlgrenska University Hospital, 41345 Gothenburg, Sweden
| | - Mia Ericson
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, 40530 Gothenburg, Sweden; (R.S.); (B.S.); (M.E.)
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5
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Schumacher S, Tahiri H, Ezan P, Rouach N, Witschas K, Leybaert L. Inhibiting astrocyte connexin-43 hemichannels blocks radiation-induced vesicular VEGF-A release and blood-brain barrier dysfunction. Glia 2024; 72:34-50. [PMID: 37670489 DOI: 10.1002/glia.24460] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 07/28/2023] [Accepted: 08/09/2023] [Indexed: 09/07/2023]
Abstract
Therapeutic brain irradiation with ionizing radiation exerts multiple side effects including barrier leakage that disturbs glial-neuronal functioning and may affect cognition. Astrocytes contribute to barrier leakage by endfeet release of various vasoactive substances acting on capillary endothelial cells forming the barrier. Here, we investigated X-ray effects on astrocytic vesicular transport in mice and determined whether interfering with astrocyte connexins affects radiation-induced barrier leakage. We found that astrocytic VEGF-A-loaded VAMP3 vesicles drastically reorganize starting from 6 h post-irradiation and move in a calcium- and Cx43-dependent manner towards endfeet where VEGF-A is released, provoking barrier leakage. Vesicular transport activation, VEGF-A release and leakage 24 h post-irradiation were all potently inhibited by astrocytic Cx43 KO, Cx43S255/262/279/282A (MK4) mutant mice and TATGap19 inhibition of Cx43 hemichannel opening. Astrocyte VEGF release is a major player in complications of brain irradiation, which can be mitigated by anti-VEGF treatments. Targeting Cx43 hemichannels allows to prevent astrocyte VEGF release at an early stage after brain irradiation.
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Affiliation(s)
- Steffi Schumacher
- Department of Basic and Applied Medical Sciences - Physiology Group, Ghent University, Ghent, Belgium
| | - Hanane Tahiri
- Department of Basic and Applied Medical Sciences - Physiology Group, Ghent University, Ghent, Belgium
| | - Pascal Ezan
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Nathalie Rouach
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Katja Witschas
- Department of Basic and Applied Medical Sciences - Physiology Group, Ghent University, Ghent, Belgium
| | - Luc Leybaert
- Department of Basic and Applied Medical Sciences - Physiology Group, Ghent University, Ghent, Belgium
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6
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Zhang W, Yin J, Gao BY, Lu X, Duan YJ, Liu XY, Li MZ, Jiang S. Inhibition of astroglial hemichannels ameliorates infrasonic noise induced short-term learning and memory impairment. BEHAVIORAL AND BRAIN FUNCTIONS : BBF 2023; 19:23. [PMID: 38110991 PMCID: PMC10726613 DOI: 10.1186/s12993-023-00226-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 12/13/2023] [Indexed: 12/20/2023]
Abstract
As a kind of environmental noise, infrasonic noise has negative effects on various human organs. To date, research has shown that infrasound impairs cognitive function, especially the ability for learning and memory. Previously, we demonstrated that impaired learning and memory induced by infrasound was closely related with glia activation; however, the underlying mechanisms remain unclear. Connexin 43 hemichannels (Cx43 HCs), which are mainly expressed in hippocampal astrocytes, are activated under pathological conditions, lending support to the hypothesis that Cx43 HCs might function in the impaired learning and memory induced by infrasound. This study revealed that that blocking hippocampal Cx43 HCs or downregulating hippocampal Cx43 expression significantly alleviated impaired learning and memory induced by infrasound. We also observed that infrasound exposure led to the abundant release of glutamate and ATP through Cx43 HCs. In addition, the abundant release of glutamate and ATP depended on proinflammatory cytokines. Our finds suggested that the enhanced release of ATP and glutamate by astroglial Cx43 HCs may be involved in the learning and memory deficits caused by infrasound exposure.
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Affiliation(s)
- Wei Zhang
- Teaching and Evaluation Center of Air Force Medical University, Xi'an, 710032, China
| | - Jue Yin
- Department of Rehabilitation Medicine, The China-Japan Friendship Hospital, No.2 Ying Hua Yuan East Street, Beijing, 100029, People's Republic of China
| | - Bei-Yao Gao
- Department of Rehabilitation Medicine, The China-Japan Friendship Hospital, No.2 Ying Hua Yuan East Street, Beijing, 100029, People's Republic of China
| | - Xi Lu
- Department of Rehabilitation Medicine, The China-Japan Friendship Hospital, No.2 Ying Hua Yuan East Street, Beijing, 100029, People's Republic of China
| | - Ya-Jing Duan
- Department of Rehabilitation Medicine, The China-Japan Friendship Hospital, No.2 Ying Hua Yuan East Street, Beijing, 100029, People's Republic of China
| | - Xu-Yan Liu
- Department of Rehabilitation Medicine, The China-Japan Friendship Hospital, No.2 Ying Hua Yuan East Street, Beijing, 100029, People's Republic of China
| | - Ming-Zhen Li
- Department of Rehabilitation Medicine, The China-Japan Friendship Hospital, No.2 Ying Hua Yuan East Street, Beijing, 100029, People's Republic of China
| | - Shan Jiang
- Department of Rehabilitation Medicine, The China-Japan Friendship Hospital, No.2 Ying Hua Yuan East Street, Beijing, 100029, People's Republic of China.
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7
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Lei L, Wang YT, Hu D, Gai C, Zhang Y. Astroglial Connexin 43-Mediated Gap Junctions and Hemichannels: Potential Antidepressant Mechanisms and the Link to Neuroinflammation. Cell Mol Neurobiol 2023; 43:4023-4040. [PMID: 37875763 DOI: 10.1007/s10571-023-01426-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 10/14/2023] [Indexed: 10/26/2023]
Abstract
Major depression disorder (MDD) is a neuropsychiatric disorder associated with a high suicide rate and a higher disability rate than any other disease. Evidence suggests that the pathological mechanism of MDD is related to astrocyte dysfunction. Depression is mainly associated with the expression of connexin 43 (Cx43) and the function of Cx43-mediated gap junctions and hemichannels in astrocytes. Moreover, neuroinflammation has been a hotspot in research on the pathology of depression, and Cx43-mediated functions are thought to be involved in neuroinflammation-related depression. However, the specific mechanism of Cx43-mediated functions in neuroinflammation-related depression pathology remains unclear. Therefore, this review summarizes and discusses Cx43 expression, the role of gap junction intercellular communication, and its relationship with neuroinflammation in depression. This review also focuses on the effects of antidepressant drugs (e.g., monoamine antidepressants, psychotropic drugs, and N-methyl-D-aspartate receptor antagonists) on Cx43-mediated function and provides evidence for Cx43 as a novel target for the treatment of MDD. The pathogenesis of MDD is related to astrocyte dysfunction, with reduced Cx43 expression, GJ dysfunction, decreased GJIC and reduced BDNF expression in the depressed brain. The effect of Cx43 on neuroinflammation-related depression involving inflammatory cytokines, glutamate excitotoxicity, and HPA axis dysregulation. Antidepressant drugs targeting Cx43 can effectively relieve depressive symptoms.
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Affiliation(s)
- Lan Lei
- Department of Anatomy, School of Chinese Medicine, Beijing University of Chinese Medicine, Sunshine Southern Avenue, Fang-Shan District, Beijing, 102488, China
| | - Ya-Ting Wang
- Department of Anatomy, School of Chinese Medicine, Beijing University of Chinese Medicine, Sunshine Southern Avenue, Fang-Shan District, Beijing, 102488, China
| | - Die Hu
- Department of Anatomy, School of Chinese Medicine, Beijing University of Chinese Medicine, Sunshine Southern Avenue, Fang-Shan District, Beijing, 102488, China
| | - Cong Gai
- Department of Anatomy, School of Chinese Medicine, Beijing University of Chinese Medicine, Sunshine Southern Avenue, Fang-Shan District, Beijing, 102488, China
| | - Yi Zhang
- Department of Anatomy, School of Chinese Medicine, Beijing University of Chinese Medicine, Sunshine Southern Avenue, Fang-Shan District, Beijing, 102488, China.
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8
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Cha H, Choi JH, Jeon H, Kim JH, Kim M, Kim SJ, Park W, Lim JS, Lee E, Ahn JS, Kim JH, Hong SH, Park JE, Jung JH, Yoo HJ, Lee S. Aquaporin-4 Deficiency is Associated with Cognitive Impairment and Alterations in astrocyte-neuron Lactate Shuttle. Mol Neurobiol 2023; 60:6212-6226. [PMID: 37436602 DOI: 10.1007/s12035-023-03475-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 07/02/2023] [Indexed: 07/13/2023]
Abstract
Cognitive impairment refers to notable declines in cognitive abilities including memory, language, and emotional stability leading to the inability to accomplish essential activities of daily living. Astrocytes play an important role in cognitive function, and homeostasis of the astrocyte-neuron lactate shuttle (ANLS) system is essential for maintaining cognitive functions. Aquaporin-4 (AQP-4) is a water channel expressed in astrocytes and has been shown to be associated with various brain disorders, but the direct relationship between learning, memory, and AQP-4 is unclear. We examined the relationship between AQP-4 and cognitive functions related to learning and memory. Mice with genetic deletion of AQP-4 showed significant behavioral and emotional changes including hyperactivity and instability, and impaired cognitive functions such as spatial learning and memory retention. 18 F-FDG PET imaging showed significant metabolic changes in the brains of AQP-4 knockout mice such as reductions in glucose absorption. Such metabolic changes in the brain seemed to be the direct results of changes in the expression of metabolite transporters, as the mRNA levels of multiple glucose and lactate transporters in astrocytes and neurons were significantly decreased in the cortex and hippocampus of AQP-4 knockout mice. Indeed, AQP-4 knockout mice showed significantly higher accumulation of both glucose and lactate in their brains compared with wild-type mice. Our results show that the deficiency of AQP-4 can cause problems in the metabolic function of astrocytes and lead to cognitive impairment, and that the deficiency of AQP4 in astrocyte endfeet can cause abnormalities in the ANLS system.
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Affiliation(s)
- Hyeuk Cha
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea
- Department of Medical Science, Asan Medical Center, Asan Medical Institute of Convergence Science and Technology, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Jun Ho Choi
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea
| | - Hanwool Jeon
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea
- Bio-Medical Institute of Technology, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Jae Hyun Kim
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea
| | - Moinay Kim
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea
| | - Su Jung Kim
- Convergence Medicine Research Center, Asan Institute for Life Sciences, Asan Medical Center, Seoul, Republic of Korea
| | - Wonhyoung Park
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea
- University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Joon Seo Lim
- Clinical Research Center, Asan Medical Center, Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Eunyeup Lee
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea
- Department of Medical Science, Asan Medical Center, Asan Medical Institute of Convergence Science and Technology, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Jae Sung Ahn
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea
- University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Jeong Hoon Kim
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea
- University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Seok Ho Hong
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea
- University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Ji Eun Park
- University of Ulsan College of Medicine, Seoul, Republic of Korea
- Department of Neuroradiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Jin Hwa Jung
- Convergence Medicine Research Center, Asan Institute for Life Sciences, Asan Medical Center, Seoul, Republic of Korea
| | - Hyun Ju Yoo
- University of Ulsan College of Medicine, Seoul, Republic of Korea
- Convergence Medicine Research Center, Asan Institute for Life Sciences, Asan Medical Center, Seoul, Republic of Korea
| | - Seungjoo Lee
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, 88, Olympic-ro 43-gil, Songpa-gu, Seoul, 05505, Republic of Korea.
- Department of Medical Science, Asan Medical Center, Asan Medical Institute of Convergence Science and Technology, University of Ulsan College of Medicine, Seoul, Republic of Korea.
- University of Ulsan College of Medicine, Seoul, Republic of Korea.
- Bio-Medical Institute of Technology, University of Ulsan College of Medicine, Seoul, Republic of Korea.
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9
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Prieto-Villalobos J, Lucero CM, Rovegno M, Gómez GI, Retamal MA, Orellana JA. SARS-CoV-2 spike protein S1 activates Cx43 hemichannels and disturbs intracellular Ca 2+ dynamics. Biol Res 2023; 56:56. [PMID: 37876016 PMCID: PMC10598968 DOI: 10.1186/s40659-023-00468-9] [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: 06/14/2023] [Accepted: 10/12/2023] [Indexed: 10/26/2023] Open
Abstract
BACKGROUND Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes the ongoing coronavirus disease 2019 (COVID-19). An aspect of high uncertainty is whether the SARS-CoV-2 per se or the systemic inflammation induced by viral infection directly affects cellular function and survival in different tissues. It has been postulated that tissue dysfunction and damage observed in COVID-19 patients may rely on the direct effects of SARS-CoV-2 viral proteins. Previous evidence indicates that the human immunodeficiency virus and its envelope protein gp120 increase the activity of connexin 43 (Cx43) hemichannels with negative repercussions for cellular function and survival. Here, we evaluated whether the spike protein S1 of SARS-CoV-2 could impact the activity of Cx43 hemichannels. RESULTS We found that spike S1 time and dose-dependently increased the activity of Cx43 hemichannels in HeLa-Cx43 cells, as measured by dye uptake experiments. These responses were potentiated when the angiotensin-converting enzyme 2 (ACE2) was expressed in HeLa-Cx43 cells. Patch clamp experiments revealed that spike S1 increased unitary current events with conductances compatible with Cx43 hemichannels. In addition, Cx43 hemichannel opening evoked by spike S1 triggered the release of ATP and increased the [Ca2+]i dynamics elicited by ATP. CONCLUSIONS We hypothesize that Cx43 hemichannels could represent potential pharmacological targets for developing therapies to counteract SARS-CoV-2 infection and their long-term consequences.
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Affiliation(s)
- Juan Prieto-Villalobos
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Claudia M Lucero
- Institute of Biomedical Sciences, Faculty of Health Sciences, Universidad Autónoma de Chile, Santiago, Chile
| | - Maximiliano Rovegno
- Departamento de Medicina Intensiva, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Gonzalo I Gómez
- Institute of Biomedical Sciences, Faculty of Health Sciences, Universidad Autónoma de Chile, Santiago, Chile
| | - Mauricio A Retamal
- Programa de Comunicación Celular en Cancer, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago, Chile.
| | - Juan A Orellana
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile.
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10
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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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11
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Lahiri A, Walton JC, Zhang N, Billington N, DeVries AC, Meares GP. Astrocytic deletion of protein kinase R-like ER kinase (PERK) does not affect learning and memory in aged mice but worsens outcome from experimental stroke. J Neurosci Res 2023; 101:1586-1610. [PMID: 37314006 PMCID: PMC10524975 DOI: 10.1002/jnr.25224] [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: 12/10/2022] [Revised: 05/22/2023] [Accepted: 05/27/2023] [Indexed: 06/15/2023]
Abstract
Aging is associated with cognitive decline and is the main risk factor for a myriad of conditions including neurodegeneration and stroke. Concomitant with aging is the progressive accumulation of misfolded proteins and loss of proteostasis. Accumulation of misfolded proteins in the endoplasmic reticulum (ER) leads to ER stress and activation of the unfolded protein response (UPR). The UPR is mediated, in part, by the eukaryotic initiation factor 2α (eIF2α) kinase protein kinase R-like ER kinase (PERK). Phosphorylation of eIF2α reduces protein translation as an adaptive mechanism but this also opposes synaptic plasticity. PERK, and other eIF2α kinases, have been widely studied in neurons where they modulate both cognitive function and response to injury. The impact of astrocytic PERK signaling in cognitive processes was previously unknown. To examine this, we deleted PERK from astrocytes (AstroPERKKO ) and examined the impact on cognitive functions in middle-aged and old mice of both sexes. Additionally, we tested the outcome following experimental stroke using the transient middle cerebral artery occlusion (MCAO) model. Tests of short-term and long-term learning and memory as well as of cognitive flexibility in middle-aged and old mice revealed that astrocytic PERK does not regulate these processes. Following MCAO, AstroPERKKO had increased morbidity and mortality. Collectively, our data demonstrate that astrocytic PERK has limited impact on cognitive function and has a more prominent role in the response to neural injury.
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Affiliation(s)
| | | | | | | | - A Courtney DeVries
- Department of Neuroscience
- Rockefeller Neuroscience Institute
- Department of Medicine, Division of Hematology and Oncology
- WVU Cancer Institute, Morgantown, WV- 26506, USA
- West Virginia Clinical and Translational Science Institute, West Virginia University, Morgantown, WV- 26506, USA
| | - Gordon P. Meares
- Department of Microbiology, Immunology and Cell Biology
- Department of Neuroscience
- Rockefeller Neuroscience Institute
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12
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León-Fuentes IM, Salgado-Gil MG, Novoa MS, Retamal MA. Connexins in Cancer, the Possible Role of Connexin46 as a Cancer Stem Cell-Determining Protein. Biomolecules 2023; 13:1460. [PMID: 37892142 PMCID: PMC10604234 DOI: 10.3390/biom13101460] [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: 08/17/2023] [Revised: 09/15/2023] [Accepted: 09/22/2023] [Indexed: 10/29/2023] Open
Abstract
Cancer is a widespread and incurable disease caused by genetic mutations, leading to uncontrolled cell proliferation and metastasis. Connexins (Cx) are transmembrane proteins that facilitate intercellular communication via hemichannels and gap junction channels. Among them, Cx46 is found mostly in the eye lens. However, in pathological conditions, Cx46 has been observed in various types of cancers, such as glioblastoma, melanoma, and breast cancer. It has been demonstrated that elevated Cx46 levels in breast cancer contribute to cellular resistance to hypoxia, and it is an enhancer of cancer aggressiveness supporting a pro-tumoral role. Accordingly, Cx46 is associated with an increase in cancer stem cell phenotype. These cells display radio- and chemoresistance, high proliferative abilities, self-renewal, and differentiation capacities. This review aims to consolidate the knowledge of the relationship between Cx46, its role in forming hemichannels and gap junctions, and its connection with cancer and cancer stem cells.
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Affiliation(s)
| | | | | | - Mauricio A. Retamal
- Programa de Comunicación Celular en Cáncer, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, República de Honduras 12740, Las Condes, Santiago 7610496, Chile; (I.M.L.-F.); (M.G.S.-G.); (M.S.N.)
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13
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Pereira MJ, Ayana R, Holt MG, Arckens L. Chemogenetic manipulation of astrocyte activity at the synapse- a gateway to manage brain disease. Front Cell Dev Biol 2023; 11:1193130. [PMID: 37534103 PMCID: PMC10393042 DOI: 10.3389/fcell.2023.1193130] [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: 03/24/2023] [Accepted: 06/14/2023] [Indexed: 08/04/2023] Open
Abstract
Astrocytes are the major glial cell type in the central nervous system (CNS). Initially regarded as supportive cells, it is now recognized that this highly heterogeneous cell population is an indispensable modulator of brain development and function. Astrocytes secrete neuroactive molecules that regulate synapse formation and maturation. They also express hundreds of G protein-coupled receptors (GPCRs) that, once activated by neurotransmitters, trigger intracellular signalling pathways that can trigger the release of gliotransmitters which, in turn, modulate synaptic transmission and neuroplasticity. Considering this, it is not surprising that astrocytic dysfunction, leading to synaptic impairment, is consistently described as a factor in brain diseases, whether they emerge early or late in life due to genetic or environmental factors. Here, we provide an overview of the literature showing that activation of genetically engineered GPCRs, known as Designer Receptors Exclusively Activated by Designer Drugs (DREADDs), to specifically modulate astrocyte activity partially mimics endogenous signalling pathways in astrocytes and improves neuronal function and behavior in normal animals and disease models. Therefore, we propose that expressing these genetically engineered GPCRs in astrocytes could be a promising strategy to explore (new) signalling pathways which can be used to manage brain disorders. The precise molecular, functional and behavioral effects of this type of manipulation, however, differ depending on the DREADD receptor used, targeted brain region and timing of the intervention, between healthy and disease conditions. This is likely a reflection of regional and disease/disease progression-associated astrocyte heterogeneity. Therefore, a thorough investigation of the effects of such astrocyte manipulation(s) must be conducted considering the specific cellular and molecular environment characteristic of each disease and disease stage before this has therapeutic applicability.
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Affiliation(s)
- Maria João Pereira
- Department of Biology, Laboratory of Neuroplasticity and Neuroproteomics, KU Leuven, Leuven, Belgium
- KU Leuven Brain Institute, Leuven, Belgium
| | - Rajagopal Ayana
- Department of Biology, Laboratory of Neuroplasticity and Neuroproteomics, KU Leuven, Leuven, Belgium
- KU Leuven Brain Institute, Leuven, Belgium
| | - Matthew G. Holt
- Instituto de Investigação e Inovação em Saúde (i3S), Laboratory of Synapse Biology, Universidade do Porto, Porto, Portugal
| | - Lutgarde Arckens
- Department of Biology, Laboratory of Neuroplasticity and Neuroproteomics, KU Leuven, Leuven, Belgium
- KU Leuven Brain Institute, Leuven, Belgium
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14
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Suthard RL, Senne RA, Buzharsky MD, Pyo AY, Dorst KE, Diep AH, Cole RH, Ramirez S. Basolateral Amygdala Astrocytes Are Engaged by the Acquisition and Expression of a Contextual Fear Memory. J Neurosci 2023; 43:4997-5013. [PMID: 37268419 PMCID: PMC10324998 DOI: 10.1523/jneurosci.1775-22.2023] [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: 09/16/2022] [Revised: 05/11/2023] [Accepted: 05/18/2023] [Indexed: 06/04/2023] Open
Abstract
Astrocytes are key cellular regulators within the brain. The basolateral amygdala (BLA) is implicated in fear memory processing, yet most research has entirely focused on neuronal mechanisms, despite a significant body of work implicating astrocytes in learning and memory. In the present study, we used in vivo fiber photometry in C57BL/6J male mice to record from amygdalar astrocytes across fear learning, recall, and three separate periods of extinction. We found that BLA astrocytes robustly responded to foot shock during acquisition, their activity remained remarkably elevated across days in comparison to unshocked control animals, and their increased activity persisted throughout extinction. Further, we found that astrocytes responded to the initiation and termination of freezing bouts during contextual fear conditioning and recall, and this behavior-locked pattern of activity did not persist throughout the extinction sessions. Importantly, astrocytes do not display these changes while exploring a novel context, suggesting that these observations are specific to the original fear-associated environment. Chemogenetic inhibition of fear ensembles in the BLA did not affect freezing behavior or astrocytic calcium dynamics. Overall, our work presents a real-time role for amygdalar astrocytes in fear processing and provides new insight into the emerging role of these cells in cognition and behavior.SIGNIFICANCE STATEMENT We show that basolateral amygdala astrocytes are robustly responsive to negative experiences, like shock, and display changed calcium activity patterns through fear learning and memory. Additionally, astrocytic calcium responses become time locked to the initiation and termination of freezing behavior during fear learning and recall. We find that astrocytes display calcium dynamics unique to a fear-conditioned context, and chemogenetic inhibition of BLA fear ensembles does not have an impact on freezing behavior or calcium dynamics. These findings show that astrocytes play a key real-time role in fear learning and memory.
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Affiliation(s)
- Rebecca L Suthard
- Graduate Program for Neuroscience, Boston University, Boston, Massachusetts 02215
- Department of Psychological and Brain Sciences, Center for Systems Neuroscience, Neurophotonics Center, and Photonics Center, Boston University, Boston, Massachusetts 02215
| | - Ryan A Senne
- Graduate Program for Neuroscience, Boston University, Boston, Massachusetts 02215
- Department of Psychological and Brain Sciences, Center for Systems Neuroscience, Neurophotonics Center, and Photonics Center, Boston University, Boston, Massachusetts 02215
| | - Michelle D Buzharsky
- Undergraduate Program in Neuroscience, Boston University, Boston, Massachusetts 02215
| | - Angela Y Pyo
- Department of Psychological and Brain Sciences, Center for Systems Neuroscience, Neurophotonics Center, and Photonics Center, Boston University, Boston, Massachusetts 02215
| | - Kaitlyn E Dorst
- Graduate Program for Neuroscience, Boston University, Boston, Massachusetts 02215
- Department of Psychological and Brain Sciences, Center for Systems Neuroscience, Neurophotonics Center, and Photonics Center, Boston University, Boston, Massachusetts 02215
| | - Anh H Diep
- Undergraduate Program in Neuroscience, Boston University, Boston, Massachusetts 02215
| | - Rebecca H Cole
- Undergraduate Program in Neuroscience, Boston University, Boston, Massachusetts 02215
| | - Steve Ramirez
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts 02215
- Department of Psychological and Brain Sciences, Center for Systems Neuroscience, Neurophotonics Center, and Photonics Center, Boston University, Boston, Massachusetts 02215
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15
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Zhang M, Wang ZZ, Chen NH. Connexin 43 Phosphorylation: Implications in Multiple Diseases. Molecules 2023; 28:4914. [PMID: 37446576 DOI: 10.3390/molecules28134914] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 06/16/2023] [Accepted: 06/20/2023] [Indexed: 07/15/2023] Open
Abstract
Connexin 43 (Cx43) is most widely distributed in mammals, especially in the cardiovascular and nervous systems. Its phosphorylation state has been found to be regulated by the action of more than ten kinases and phosphatases, including mitogen-activated protein kinase/extracellular signaling and regulating kinase signaling. In addition, the phosphorylation status of different phosphorylation sites affects its own synthesis and assembly and the function of the gap junctions (GJs) to varying degrees. The phosphorylation of Cx43 can affect the permeability, electrical conductivity, and gating properties of GJs, thereby having various effects on intercellular communication and affecting physiological or pathological processes in vitro and in vivo. Therefore, clarifying the relationship between Cx43 phosphorylation and specific disease processes will help us better understand the disease. Based on the above clinical and preclinical findings, we present in this review the functional significance of Cx43 phosphorylation in multiple diseases and discuss the potential of Cx43 as a drug target in Cx43-related disease pathophysiology, with an emphasis on the importance of connexin 43 as an emerging therapeutic target in cardiac and neuroprotection.
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Affiliation(s)
- Meng Zhang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100050, China
| | - Zhen-Zhen Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100050, China
| | - Nai-Hong Chen
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Science and Peking Union Medical College, Beijing 100050, China
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16
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Huang SN, Pan YT, Zhou YP, Wang XZ, Mei MJ, Yang B, Li D, Zeng WB, Cheng S, Sun JY, Cheng H, Zhao F, Luo MH. Human Cytomegalovirus IE1 Impairs Neuronal Migration by Downregulating Connexin 43. J Virol 2023; 97:e0031323. [PMID: 37097169 PMCID: PMC10231247 DOI: 10.1128/jvi.00313-23] [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: 02/27/2023] [Accepted: 04/07/2023] [Indexed: 04/26/2023] Open
Abstract
Human cytomegalovirus (HCMV) is a leading cause of congenital birth defects. Though the underlying mechanisms remain poorly characterized, mouse models of congenital CMV infection have demonstrated that the neuronal migration process is damaged. In this study, we evaluated the effects of HCMV infection on connexin 43 (Cx43), a crucial adhesion molecule mediating neuronal migration. We show in multiple cellular models that HCMV infection downregulated Cx43 posttranslationally. Further analysis identified the immediate early protein IE1 as the viral protein responsible for the reduction of Cx43. IE1 was found to bind the Cx43 C terminus and promote Cx43 degradation through the ubiquitin-proteasome pathway. Deletion of the Cx43-binding site in IE1 rendered it incapable of inducing Cx43 degradation. We validated the IE1-induced loss of Cx43 in vivo by introducing IE1 into the fetal mouse brain. Noteworthily, ectopic IE1 expression induced cortical atrophy and neuronal migration defects. Several lines of evidence suggest that these damages result from decreased Cx43, and restoration of Cx43 levels partially rescued IE1-induced interruption of neuronal migration. Taken together, the results of our investigation reveal a novel mechanism of HCMV-induced neural maldevelopment and identify a potential intervention target. IMPORTANCE Congenital CMV (cCMV) infection causes neurological sequelae in newborns. Recent studies of cCMV pathogenesis in animal models reveal ventriculomegaly and cortical atrophy associated with impaired neural progenitor cell (NPC) proliferation and migration. In this study, we investigated the mechanisms underlying these NPC abnormalities. We show that Cx43, a critical adhesion molecule mediating NPC migration, is downregulated by HCMV infection in vitro and HCMV-IE1 in vivo. We provide evidence that IE1 interacts with the C terminus of Cx43 to promote its ubiquitination and consequent degradation through the proteasome. Moreover, we demonstrate that introducing IE1 into mouse fetal brains led to neuronal migration defects, which was associated with Cx43 reduction. Deletion of the Cx43-binding region in IE1 or ectopic expression of Cx43 rescued the IE1-induced migration defects in vivo. Our study provides insight into how cCMV infection impairs neuronal migration and reveals a target for therapeutic interventions.
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Affiliation(s)
- Sheng-Nan Huang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yu-Ting Pan
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yue-Peng Zhou
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy of Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, China
| | - Xian-Zhang Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Meng-Jie Mei
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Bo Yang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
- The Joint Center of Translational Precision Medicine, Guangzhou Institute of Pediatrics, Guangzhou Women and Children Medical Center, Guangzhou, China
| | - Dong Li
- Chinese Institute for Brain Research, Beijing, China
- School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Wen-Bo Zeng
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Shuang Cheng
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Jin-Yan Sun
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Han Cheng
- Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Fei Zhao
- Chinese Institute for Brain Research, Beijing, China
- School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Min-Hua Luo
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy of Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, China
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17
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Chen YH, Jin SY, Yang JM, Gao TM. The Memory Orchestra: Contribution of Astrocytes. Neurosci Bull 2023; 39:409-424. [PMID: 36738435 PMCID: PMC10043126 DOI: 10.1007/s12264-023-01024-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 01/03/2023] [Indexed: 02/05/2023] Open
Abstract
For decades, memory research has centered on the role of neurons, which do not function in isolation. However, astrocytes play important roles in regulating neuronal recruitment and function at the local and network levels, forming the basis for information processing as well as memory formation and storage. In this review, we discuss the role of astrocytes in memory functions and their cellular underpinnings at multiple time points. We summarize important breakthroughs and controversies in the field as well as potential avenues to further illuminate the role of astrocytes in memory processes.
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Affiliation(s)
- Yi-Hua Chen
- State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China.
| | - Shi-Yang Jin
- State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Jian-Ming Yang
- State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Tian-Ming Gao
- State Key Laboratory of Organ Failure Research, Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China.
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18
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Chang CWT, Poudyal N, Verdugo DA, Peña F, Stehberg J, Retamal MA. KI04 an Aminoglycosides-Derived Molecule Acts as an Inhibitor of Human Connexin46 Hemichannels Expressed in HeLa Cells. Biomolecules 2023; 13:411. [PMID: 36979346 PMCID: PMC10046693 DOI: 10.3390/biom13030411] [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: 01/21/2023] [Revised: 02/12/2023] [Accepted: 02/16/2023] [Indexed: 02/24/2023] Open
Abstract
BACKGROUND Connexins (Cxs) are proteins that help cells to communicate with the extracellular media and with the cytoplasm of neighboring cells. Despite their importance in several human physiological and pathological conditions, their pharmacology is very poor. In the last decade, some molecules derived from aminoglycosides have been developed as inhibitors of Cxs hemichannels. However, these studies have been performed in E. coli, which is a very simple model. Therefore, our main goal is to test whether these molecules have similar effects in mammalian cells. METHODS We transfected HeLa cells with the human Cx46tGFP and characterized the effect of a kanamycin-derived molecule (KI04) on Cx46 hemichannel activity by time-lapse recordings, changes in phosphorylation by Western blot, localization by epifluorescence, and possible binding sites by molecular dynamics (MD). RESULTS We observed that kanamycin and KI04 were the most potent inhibitors of Cx46 hemichannels among several aminoglycosides, presenting an IC50 close to 10 μM. The inhibitory effect was not associated with changes in Cx46 electrophoretic mobility or its intracellular localization. Interestingly, 5 mM DTT did not reverse KI04 inhibition, but the KI04 effect completely disappeared after washing out KI04 from the recording media. MD analysis revealed two putative binding sites of KI04 in the Cx46 hemichannel. RESULTS These results demonstrate that KI04 could be used as a Cx46 inhibitor and could help to develop future selective Cx46 inhibitors.
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Affiliation(s)
- Cheng-Wei T. Chang
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322-0300, USA
| | - Naveena Poudyal
- Department of Chemistry and Biochemistry, Utah State University, Logan, UT 84322-0300, USA
| | - Daniel A. Verdugo
- Laboratorio de Neurobiología, Facultad de Medicina y Facultad de Ciencias de la Vida, Instituto de Ciencias Biomédicas, Universidad Andres Bello, Santiago 7780272, Chile
| | - Francisca Peña
- Laboratorio de Neurobiología, Facultad de Medicina y Facultad de Ciencias de la Vida, Instituto de Ciencias Biomédicas, Universidad Andres Bello, Santiago 7780272, Chile
| | - Jimmy Stehberg
- Laboratorio de Neurobiología, Facultad de Medicina y Facultad de Ciencias de la Vida, Instituto de Ciencias Biomédicas, Universidad Andres Bello, Santiago 7780272, Chile
| | - Mauricio A. Retamal
- Center for Membrane Protein Research, Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, TX 79430-6551, USA
- Programa de Comunicación Celular en Cáncer, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago 7610496, Chile
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19
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Murray CJ, Vecchiarelli HA, Tremblay MÈ. Enhancing axonal myelination in seniors: A review exploring the potential impact cannabis has on myelination in the aged brain. Front Aging Neurosci 2023; 15:1119552. [PMID: 37032821 PMCID: PMC10073480 DOI: 10.3389/fnagi.2023.1119552] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 02/22/2023] [Indexed: 04/11/2023] Open
Abstract
Consumption of cannabis is on the rise as public opinion trends toward acceptance and its consequent legalization. Specifically, the senior population is one of the demographics increasing their use of cannabis the fastest, but research aimed at understanding cannabis' impact on the aged brain is still scarce. Aging is characterized by many brain changes that slowly alter cognitive ability. One process that is greatly impacted during aging is axonal myelination. The slow degradation and loss of myelin (i.e., demyelination) in the brain with age has been shown to associate with cognitive decline and, furthermore, is a common characteristic of numerous neurological diseases experienced in aging. It is currently not known what causes this age-dependent degradation, but it is likely due to numerous confounding factors (i.e., heightened inflammation, reduced blood flow, cellular senescence) that impact the many cells responsible for maintaining overall homeostasis and myelin integrity. Importantly, animal studies using non-human primates and rodents have also revealed demyelination with age, providing a reliable model for researchers to try and understand the cellular mechanisms at play. In rodents, cannabis was recently shown to modulate the myelination process. Furthermore, studies looking at the direct modulatory impact cannabis has on microglia, astrocytes and oligodendrocyte lineage cells hint at potential mechanisms to prevent some of the more damaging activities performed by these cells that contribute to demyelination in aging. However, research focusing on how cannabis impacts myelination in the aged brain is lacking. Therefore, this review will explore the evidence thus far accumulated to show how cannabis impacts myelination and will extrapolate what this knowledge may mean for the aged brain.
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Affiliation(s)
- Colin J. Murray
- Neuroscience Graduate Program, University of Victoria, Victoria, BC, Canada
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- *Correspondence: Colin J. Murray,
| | | | - Marie-Ève Tremblay
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Départment de Médicine Moléculaire, Université Laval, Québec City, QC, Canada
- Axe Neurosciences, Center de Recherche du CHU de Québec, Université Laval, Québec City, QC, Canada
- Neurology and Neurosurgery Department, McGill University, Montréal, QC, Canada
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
- Centre for Advanced Materials and Related Technology (CAMTEC), University of Victoria, Victoria, BC, Canada
- Institute for Aging and Lifelong Health, University of Victoria, Victoria, BC, Canada
- Marie-Ève Tremblay,
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20
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Garré JM, Bukauskas FF, Bennett MVL. Single channel properties of pannexin-1 and connexin-43 hemichannels and P2X7 receptors in astrocytes cultured from rodent spinal cords. Glia 2022; 70:2260-2275. [PMID: 35915989 PMCID: PMC9560969 DOI: 10.1002/glia.24250] [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: 02/26/2022] [Revised: 07/12/2022] [Accepted: 07/13/2022] [Indexed: 11/11/2022]
Abstract
Astrocytes express surface channels involved in purinergic signaling. Among these channels, pannexin-1 (Px1) and connexin-43 (Cx43) hemichannels (HCs) release ATP that acts directly, or through its derivatives, on neurons and glia via purinergic receptors. Although HCs are functional, that is, open and close under physiological and pathological conditions, single channel properties of Px1 HCs in astrocytes have not been defined. Here, we developed a dual voltage clamp technique in HeLa cells expressing human Px1-YFP, and then applied this system to rodent spinal astrocytes to compare their single channel properties with other surface channels, that is, Cx43 HCs and P2X7 receptors (P2X7Rs). Channels were recorded in cell attached patches and evoked with ramp cycles applied through another pipette in whole cell voltage clamp. The mean unitary conductances of Px1 HCs were comparable in HeLa Px1-YFP cells and spinal astrocytes, ~42 and ~48 pS, respectively. Based on their unitary conductance, voltage-dependence, and unitary activity after pharmacological and gene silencing, Px1 HCs in astrocytes could be distinguished from Cx43 HCs and P2X7Rs. Channel activity of Px1 HCs and P2X7Rs was greater than that of Cx43 HCs in control astrocytes during ramps. Unitary activity of Px1 HCs was decreased and that of Cx43 HCs and P2X7Rs increased in astrocytes treated with fibroblast growth factor 1 (FGF-1). In summary, we resolved single channel properties of three different surface channels involved in purinergic signaling in spinal astrocytes, which were differentially modulated by FGF-1, a growth factor involved in neurodevelopment, inflammation and repair.
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Affiliation(s)
- Juan Mauricio Garré
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Feliksas F Bukauskas
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Michael V L Bennett
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, USA
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21
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Jiménez-Dinamarca I, Reyes-Lizana R, Lemunao-Inostroza Y, Cárdenas K, Castro-Lazo R, Peña F, Lucero CM, Prieto-Villalobos J, Retamal MA, Orellana JA, Stehberg J. GABAergic Regulation of Astroglial Gliotransmission through Cx43 Hemichannels. Int J Mol Sci 2022; 23:13625. [PMID: 36362410 PMCID: PMC9656947 DOI: 10.3390/ijms232113625] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 09/30/2022] [Accepted: 10/09/2022] [Indexed: 02/12/2024] Open
Abstract
Gamma-Aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the brain. It is produced by interneurons and recycled by astrocytes. In neurons, GABA activates the influx of Cl- via the GABAA receptor or efflux or K+ via the GABAB receptor, inducing hyperpolarization and synaptic inhibition. In astrocytes, the activation of both GABAA and GABAB receptors induces an increase in intracellular Ca2+ and the release of glutamate and ATP. Connexin 43 (Cx43) hemichannels are among the main Ca2+-dependent cellular mechanisms for the astroglial release of glutamate and ATP. However, no study has evaluated the effect of GABA on astroglial Cx43 hemichannel activity and Cx43 hemichannel-mediated gliotransmission. Here we assessed the effects of GABA on Cx43 hemichannel activity in DI NCT1 rat astrocytes and hippocampal brain slices. We found that GABA induces a Ca2+-dependent increase in Cx43 hemichannel activity in astrocytes mediated by the GABAA receptor, as it was blunted by the GABAA receptor antagonist bicuculline but unaffected by GABAB receptor antagonist CGP55845. Moreover, GABA induced the Cx43 hemichannel-dependent release of glutamate and ATP, which was also prevented by bicuculline, but unaffected by CGP. Gliotransmission in response to GABA was also unaffected by pannexin 1 channel blockade. These results are discussed in terms of the possible role of astroglial Cx43 hemichannel-mediated glutamate and ATP release in regulating the excitatory/inhibitory balance in the brain and their possible contribution to psychiatric disorders.
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Affiliation(s)
- Ivanka Jiménez-Dinamarca
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago 8370186, Chile
| | - Rachel Reyes-Lizana
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago 8370186, Chile
| | - Yordan Lemunao-Inostroza
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago 8370186, Chile
| | - Kevin Cárdenas
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago 8370186, Chile
| | - Raimundo Castro-Lazo
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago 8370186, Chile
| | - Francisca Peña
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago 8370186, Chile
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Universidad del Desarrollo–Clínica Alemana, Santiago 7780272, Chile
| | - Claudia M. Lucero
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile
| | - Juan Prieto-Villalobos
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile
| | - Mauricio Antonio Retamal
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Universidad del Desarrollo–Clínica Alemana, Santiago 7780272, Chile
| | - Juan Andrés Orellana
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile
| | - Jimmy Stehberg
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad Andres Bello, Santiago 8370186, Chile
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22
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Portal B, Vasile F, Zapata J, Lejards C, Ait Tayeb AEK, Colle R, Verstuyft C, Corruble E, Rouach N, Guiard BP. Astroglial Connexins Inactivation Increases Relapse of Depressive-like Phenotype after Antidepressant Withdrawal. Int J Mol Sci 2022; 23:13227. [PMID: 36362016 PMCID: PMC9656718 DOI: 10.3390/ijms232113227] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 10/26/2022] [Accepted: 10/28/2022] [Indexed: 09/11/2023] Open
Abstract
Studies suggest that astrocytic connexins (Cx) have an important role in the regulation of high brain functions through their ability to establish fine-tuned communication with neurons within the tripartite synapse. In light of these properties, growing evidence suggests a role of Cx in psychiatric disorders such as major depression but also in the therapeutic activity of antidepressant drugs. However, the real impact of Cx on treatment response and the underlying neurobiological mechanisms remain yet to be clarified. On this ground, the present study was designed to evaluate the functional activity of Cx in a mouse model of depression based on chronic corticosterone exposure and to determine to which extent their pharmacological inactivation influences the antidepressant-like activity of venlafaxine (VENLA). On the one hand, our results indicate that depressed mice have impaired Cx-based gap-junction and hemichannel activities. On the other hand, while VENLA exerts robust antidepressant-like activity in depressed mice; this effect is abolished by the pharmacological inhibition of Cx with carbenoxolone (CBX). Interestingly, the combination of VENLA and CBX is also associated with a higher rate of relapse after treatment withdrawal. To our knowledge, this study is one of the first to develop a model of relapse, and our results reveal that Cx-mediated dynamic neuroglial interactions play a critical role in the efficacy of monoaminergic antidepressant drugs, thus providing new targets for the treatment of depression.
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Affiliation(s)
- Benjamin Portal
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, Université de Toulouse, CNRS, 31062 Toulouse, France
| | - Flora Vasile
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, 75005 Paris, France
| | - Jonathan Zapata
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, 75005 Paris, France
| | - Camille Lejards
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, Université de Toulouse, CNRS, 31062 Toulouse, France
| | - Abd El Kader Ait Tayeb
- CESP, MOODS Team, INSERM, Faculté de Médecine, University of Paris-Saclay, 94275 Le Kremlin Bicêtre, France
- Service Hospitalo-Universitaire de Psychiatrie de Bicêtre, Hôpitaux Universitaires Paris-Saclay, Assistance Publique-Hôpitaux de Paris, Hôpital de Bicêtre, 94275 Le Kremlin Bicêtre, France
| | - Romain Colle
- CESP, MOODS Team, INSERM, Faculté de Médecine, University of Paris-Saclay, 94275 Le Kremlin Bicêtre, France
- Service Hospitalo-Universitaire de Psychiatrie de Bicêtre, Hôpitaux Universitaires Paris-Saclay, Assistance Publique-Hôpitaux de Paris, Hôpital de Bicêtre, 94275 Le Kremlin Bicêtre, France
| | - Céline Verstuyft
- CESP, MOODS Team, INSERM, Faculté de Médecine, University of Paris-Saclay, 94275 Le Kremlin Bicêtre, France
- Service de Génétique Moléculaire, Pharmacogénétique et Hormonologie de Bicêtre, Hôpitaux Universitaires Paris-Saclay, Assistance Publique-Hôpitaux de Paris, Hôpital de Bicêtre, 94275 Le Kremlin Bicêtre, France
| | - Emmanuelle Corruble
- CESP, MOODS Team, INSERM, Faculté de Médecine, University of Paris-Saclay, 94275 Le Kremlin Bicêtre, France
- Service Hospitalo-Universitaire de Psychiatrie de Bicêtre, Hôpitaux Universitaires Paris-Saclay, Assistance Publique-Hôpitaux de Paris, Hôpital de Bicêtre, 94275 Le Kremlin Bicêtre, France
| | - Nathalie Rouach
- Neuroglial Interactions in Cerebral Physiopathology, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, 75005 Paris, France
| | - Bruno P. Guiard
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, Université de Toulouse, CNRS, 31062 Toulouse, France
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23
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Zhang NN, Zhang Y, Wang ZZ, Chen NH. Connexin 43: insights into candidate pathological mechanisms of depression and its implications in antidepressant therapy. Acta Pharmacol Sin 2022; 43:2448-2461. [PMID: 35145238 PMCID: PMC9525669 DOI: 10.1038/s41401-022-00861-2] [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: 08/30/2021] [Accepted: 01/06/2022] [Indexed: 11/09/2022] Open
Abstract
Major depressive disorder (MDD), a chronic and recurrent disease characterized by anhedonia, pessimism or even suicidal thought, remains a major chronic mental concern worldwide. Connexin 43 (Cx43) is the most abundant connexin expressed in astrocytes and forms the gap junction channels (GJCs) between astrocytes, the most abundant and functional glial cells in the brain. Astrocytes regulate neurons' synaptic strength and function by expressing receptors and regulating various neurotransmitters. Astrocyte dysfunction causes synaptic abnormalities, which are related to various mood disorders, e.g., depression. Increasing evidence suggests a crucial role of Cx43 in the pathogenesis of depression. Depression down-regulates Cx43 expression in humans and rats, and dysfunction of Cx43 also induces depressive behaviors in rats and mice. Recently Cx43 has received considerable critical attention and is highly implicated in the onset of depression. However, the pathological mechanisms of depression-like behavior associated with Cx43 still remain ambiguous. In this review we summarize the recent progress regarding the underlying mechanisms of Cx43 in the etiology of depression-like behaviors including gliotransmission, metabolic disorders, and neuroinflammation. We also discuss the effects of antidepressants (monoamine antidepressants and ketamine) on Cx43. The clarity of the candidate pathological mechanisms of depression-like behaviors associated with Cx43 and its potential pharmacological roles for antidepressants will benefit the exploration of a novel antidepressant target.
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Affiliation(s)
- Ning-Ning Zhang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Yi Zhang
- Department of Anatomy, School of Chinese Medicine, Beijing University of Chinese Medicine, Beijing, 102488, China
| | - Zhen-Zhen Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China.
| | - Nai-Hong Chen
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica & Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China.
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24
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Zlomuzica A, Plank L, Dere E. A new path to mental disorders: Through gap junction channels and hemichannels. Neurosci Biobehav Rev 2022; 142:104877. [PMID: 36116574 DOI: 10.1016/j.neubiorev.2022.104877] [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: 01/31/2022] [Revised: 08/20/2022] [Accepted: 09/13/2022] [Indexed: 11/18/2022]
Abstract
Behavioral disturbances related to emotional regulation, reward processing, cognition, sleep-wake regulation and activity/movement represent core symptoms of most common mental disorders. Increasing empirical and theoretical evidence suggests that normal functioning of these behavioral domains relies on fine graded coordination of neural and glial networks which are maintained and modulated by intercellular gap junction channels and unapposed pannexin or connexin hemichannels. Dysfunctions in these networks might contribute to the development and maintenance of psychopathological and neurobiological features associated with mental disorders. Here we review and discuss the evidence indicating a prominent role of gap junction channel and hemichannel dysfunction in core symptoms of mental disorders. We further discuss how the increasing knowledge on intercellular gap junction channels and unapposed pannexin or connexin hemichannels in the brain might lead to deeper mechanistic insight in common mental disorders and to the development of novel treatment approaches. We further attempt to exemplify what type of future research on this topic could be integrated into multidimensional approaches to understand and cure mental disorders.
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Affiliation(s)
- Armin Zlomuzica
- Department of Behavioral and Clinical Neuroscience, Ruhr-University Bochum (RUB), Massenbergstraße 9-13, D-44787 Bochum, Germany.
| | - Laurin Plank
- Department of Behavioral and Clinical Neuroscience, Ruhr-University Bochum (RUB), Massenbergstraße 9-13, D-44787 Bochum, Germany
| | - Ekrem Dere
- Department of Behavioral and Clinical Neuroscience, Ruhr-University Bochum (RUB), Massenbergstraße 9-13, D-44787 Bochum, Germany; Sorbonne Université. Institut de Biologie Paris-Seine, (IBPS), Département UMR 8256: Adaptation Biologique et Vieillissement, UFR des Sciences de la Vie, Campus Pierre et Marie Curie, Bâtiment B, 9 quai Saint Bernard, F-75005 Paris, France.
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25
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Fernández-Olivares A, Durán-Jara E, Verdugo DA, Fiori MC, Altenberg GA, Stehberg J, Alfaro I, Calderón JF, Retamal MA. Extracellular Cysteines Are Critical to Form Functional Cx46 Hemichannels. Int J Mol Sci 2022; 23:7252. [PMID: 35806258 PMCID: PMC9266770 DOI: 10.3390/ijms23137252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/16/2022] [Accepted: 06/18/2022] [Indexed: 12/10/2022] Open
Abstract
Connexin (Cxs) hemichannels participate in several physiological and pathological processes, but the molecular mechanisms that control their gating remain elusive. We aimed at determining the role of extracellular cysteines (Cys) in the gating and function of Cx46 hemichannels. We studied Cx46 and mutated all of its extracellular Cys to alanine (Ala) (one at a time) and studied the effects of the Cys mutations on Cx46 expression, localization, and hemichannel activity. Wild-type Cx46 and Cys mutants were expressed at comparable levels, with similar cellular localization. However, functional experiments showed that hemichannels formed by the Cys mutants did not open either in response to membrane depolarization or removal of extracellular divalent cations. Molecular-dynamics simulations showed that Cys mutants may show a possible alteration in the electrostatic potential of the hemichannel pore and an altered disposition of important residues that could contribute to the selectivity and voltage dependency in the hemichannels. Replacement of extracellular Cys resulted in "permanently closed hemichannels", which is congruent with the inhibition of the Cx46 hemichannel by lipid peroxides, through the oxidation of extracellular Cys. These results point to the modification of extracellular Cys as potential targets for the treatment of Cx46-hemichannel associated pathologies, such as cataracts and cancer, and may shed light into the gating mechanisms of other Cx hemichannels.
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Affiliation(s)
- Ainoa Fernández-Olivares
- Programa de Comunicación Celular en Cáncer, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago 7780272, Chile; (A.F.-O.); (I.A.)
| | - Eduardo Durán-Jara
- Centro de Medicina Regenerativa, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago 7780272, Chile;
| | - Daniel A. Verdugo
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina y Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 7780272, Chile; (D.A.V.); (J.S.)
| | - Mariana C. Fiori
- Department of Cell Physiology and Molecular Biophysics and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX 79430-6551, USA; (M.C.F.); (G.A.A.)
| | - Guillermo A. Altenberg
- Department of Cell Physiology and Molecular Biophysics and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX 79430-6551, USA; (M.C.F.); (G.A.A.)
| | - Jimmy Stehberg
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de Medicina y Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 7780272, Chile; (D.A.V.); (J.S.)
| | - Iván Alfaro
- Programa de Comunicación Celular en Cáncer, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago 7780272, Chile; (A.F.-O.); (I.A.)
- Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Santiago 7690000, Chile
| | - Juan Francisco Calderón
- Centro de Genética y Genómica, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago 7780272, Chile
| | - Mauricio A. Retamal
- Programa de Comunicación Celular en Cáncer, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago 7780272, Chile; (A.F.-O.); (I.A.)
- Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Santiago 7690000, Chile
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago 7690000, Chile
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26
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Neurodegeneration in Multiple Sclerosis: The Role of Nrf2-Dependent Pathways. Antioxidants (Basel) 2022; 11:antiox11061146. [PMID: 35740042 PMCID: PMC9219619 DOI: 10.3390/antiox11061146] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 06/06/2022] [Accepted: 06/08/2022] [Indexed: 12/10/2022] Open
Abstract
Multiple sclerosis (MS) encompasses a chronic, irreversible, and predominantly immune-mediated disease of the central nervous system that leads to axonal degeneration, neuronal death, and several neurological symptoms. Although various immune therapies have reduced relapse rates and the severity of symptoms in relapsing-remitting MS, there is still no cure for this devastating disease. In this brief review, we discuss the role of mitochondria dysfunction in the progression of MS, focused on the possible role of Nrf2 signaling in orchestrating the impairment of critical cellular and molecular aspects such as reactive oxygen species (ROS) management, under neuroinflammation and neurodegeneration in MS. In this scenario, we propose a new potential downstream signaling of Nrf2 pathway, namely the opening of hemichannels and pannexons. These large-pore channels are known to modulate glial/neuronal function and ROS production as they are permeable to extracellular Ca2+ and release potentially harmful transmitters to the synaptic cleft. In this way, the Nrf2 dysfunction impairs not only the bioenergetics and metabolic properties of glial cells but also the proper antioxidant defense and energy supply that they provide to neurons.
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27
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Lei Z, Xie L, Li CH, Lam YY, Ramkrishnan AS, Fu Z, Zeng X, Liu S, Iqbal Z, Li Y. Chemogenetic Activation of Astrocytes in the Basolateral Amygdala Contributes to Fear Memory Formation by Modulating the Amygdala–Prefrontal Cortex Communication. Int J Mol Sci 2022; 23:ijms23116092. [PMID: 35682767 PMCID: PMC9181030 DOI: 10.3390/ijms23116092] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 05/25/2022] [Accepted: 05/27/2022] [Indexed: 02/01/2023] Open
Abstract
The basolateral amygdala (BLA) is one of the key brain areas involved in aversive learning, especially fear memory formation. Studies of aversive learning in the BLA have largely focused on neuronal function, while the role of BLA astrocytes in aversive learning remains largely unknown. In this study, we manipulated the BLA astrocytes by expressing the Gq-coupled receptor hM3q and discovered that astrocytic Gq modulation during fear conditioning promoted auditorily cued fear memory but did not affect less stressful memory tasks or induce anxiety-like behavior. Moreover, chemogenetic activation of BLA astrocytes during memory retrieval had no effect on fear memory expression. In addition, astrocytic Gq activation increased c-Fos expression in the BLA and the medial prefrontal cortex (mPFC) during fear conditioning, but not in the home cage. Combining these results with retrograde virus tracing, we found that the activity of mPFC-projecting BLA neurons showed significant enhancement after astrocytic Gq activation during fear conditioning. Electrophysiology recordings showed that activating astrocytic Gq in the BLA promoted spike-field coherence and phase locking percentage, not only within the BLA but also between the BLA and the mPFC. Finally, direct chemogenetic activation of mPFC-projecting BLA neurons during fear conditioning enhanced cued fear memory. Taken together, our data suggest that astrocytes in the BLA may contribute to aversive learning by modulating amygdala–mPFC communication.
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Affiliation(s)
- Zhuogui Lei
- Department of Neuroscience, City University of Hong Kong, Hong Kong 999077, China; (Z.L.); (L.X.); (A.S.R.); (Z.F.); (S.L.); (Z.I.)
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong 999077, China; (C.H.L.); (Y.Y.L.); (X.Z.)
| | - Li Xie
- Department of Neuroscience, City University of Hong Kong, Hong Kong 999077, China; (Z.L.); (L.X.); (A.S.R.); (Z.F.); (S.L.); (Z.I.)
| | - Cheuk Hin Li
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong 999077, China; (C.H.L.); (Y.Y.L.); (X.Z.)
| | - Yuk Yan Lam
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong 999077, China; (C.H.L.); (Y.Y.L.); (X.Z.)
| | - Aruna Surendran Ramkrishnan
- Department of Neuroscience, City University of Hong Kong, Hong Kong 999077, China; (Z.L.); (L.X.); (A.S.R.); (Z.F.); (S.L.); (Z.I.)
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong 999077, China; (C.H.L.); (Y.Y.L.); (X.Z.)
| | - Zhongqi Fu
- Department of Neuroscience, City University of Hong Kong, Hong Kong 999077, China; (Z.L.); (L.X.); (A.S.R.); (Z.F.); (S.L.); (Z.I.)
- Centre for Regenerative Medicine and Health, Hong Kong Institute of Science & Innovation, Chinese Academy of Sciences, Hong Kong 999077, China
| | - Xianlin Zeng
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong 999077, China; (C.H.L.); (Y.Y.L.); (X.Z.)
| | - Shu Liu
- Department of Neuroscience, City University of Hong Kong, Hong Kong 999077, China; (Z.L.); (L.X.); (A.S.R.); (Z.F.); (S.L.); (Z.I.)
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong 999077, China; (C.H.L.); (Y.Y.L.); (X.Z.)
| | - Zafar Iqbal
- Department of Neuroscience, City University of Hong Kong, Hong Kong 999077, China; (Z.L.); (L.X.); (A.S.R.); (Z.F.); (S.L.); (Z.I.)
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong 999077, China; (C.H.L.); (Y.Y.L.); (X.Z.)
| | - Ying Li
- Department of Neuroscience, City University of Hong Kong, Hong Kong 999077, China; (Z.L.); (L.X.); (A.S.R.); (Z.F.); (S.L.); (Z.I.)
- Department of Biomedical Sciences, City University of Hong Kong, Hong Kong 999077, China; (C.H.L.); (Y.Y.L.); (X.Z.)
- Centre for Regenerative Medicine and Health, Hong Kong Institute of Science & Innovation, Chinese Academy of Sciences, Hong Kong 999077, China
- Centre for Biosystems, Neuroscience, and Nanotechnology, City University of Hong Kong, Hong Kong 999077, China
- Correspondence:
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Cheng YT, Woo J, Deneen B. Sculpting Astrocyte Diversity through Circuits and Transcription. Neuroscientist 2022:10738584221082620. [PMID: 35373633 PMCID: PMC9526762 DOI: 10.1177/10738584221082620] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Astrocytes are the most abundant glial cell in the central nervous system and occupy a wide range of roles that are essential for brain function. Over the past few years, evidence has emerged that astrocytes exhibit cellular and molecular heterogeneity, raising the possibility that subsets of astrocytes are functionally distinct and that transcriptional mechanisms are involved in encoding this prospective diversity. In this review, we focus on three emerging areas of astrocyte biology: region-specific circuit regulation, molecular diversity, and transcriptional regulation. This review highlights our nascent understanding of how molecular diversity is converted to functional diversity of astrocytes through the lens of brain region-specific circuits. We articulate our understanding of how transcriptional mechanisms regulate this diversity and key areas that need further exploration to achieve the overarching goal of a functional taxonomy of astrocytes in the brain.
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Affiliation(s)
- Yi-Ting Cheng
- Program in Developmental Biology, Baylor College of Medicine, Houston, Houston, TX, USA.,Center for Cell and Gene Therapy, Texas Children's Hospital, Houston, TX, USA
| | - Junsung Woo
- Center for Cell and Gene Therapy, Texas Children's Hospital, Houston, TX, USA
| | - Benjamin Deneen
- Program in Developmental Biology, Baylor College of Medicine, Houston, Houston, TX, USA.,Center for Cell and Gene Therapy, Texas Children's Hospital, Houston, TX, USA.,Department of Neurosurgery, Baylor College of Medicine, Houston, TX, USA
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29
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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: 22] [Impact Index Per Article: 11.0] [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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Hösli L, Binini N, Ferrari KD, Thieren L, Looser ZJ, Zuend M, Zanker HS, Berry S, Holub M, Möbius W, Ruhwedel T, Nave KA, Giaume C, Weber B, Saab AS. Decoupling astrocytes in adult mice impairs synaptic plasticity and spatial learning. Cell Rep 2022; 38:110484. [PMID: 35263595 DOI: 10.1016/j.celrep.2022.110484] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 11/20/2021] [Accepted: 02/14/2022] [Indexed: 12/16/2022] Open
Abstract
The mechanisms by which astrocytes modulate neural homeostasis, synaptic plasticity, and memory are still poorly explored. Astrocytes form large intercellular networks by gap junction coupling, mainly composed of two gap junction channel proteins, connexin 30 (Cx30) and connexin 43 (Cx43). To circumvent developmental perturbations and to test whether astrocytic gap junction coupling is required for hippocampal neural circuit function and behavior, we generate and study inducible, astrocyte-specific Cx30 and Cx43 double knockouts. Surprisingly, disrupting astrocytic coupling in adult mice results in broad activation of astrocytes and microglia, without obvious signs of pathology. We show that hippocampal CA1 neuron excitability, excitatory synaptic transmission, and long-term potentiation are significantly affected. Moreover, behavioral inspection reveals deficits in sensorimotor performance and a complete lack of spatial learning and memory. Together, our findings establish that astrocytic connexins and an intact astroglial network in the adult brain are vital for neural homeostasis, plasticity, and spatial cognition.
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Affiliation(s)
- Ladina Hösli
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
| | - Noemi Binini
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
| | - Kim David Ferrari
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
| | - Laetitia Thieren
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
| | - Zoe J Looser
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
| | - Marc Zuend
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
| | - Henri S Zanker
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
| | - Stewart Berry
- Brain Research Institute, University of Zurich, 8057 Zurich, Switzerland
| | - Martin Holub
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
| | - Wiebke Möbius
- Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Torben Ruhwedel
- Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Klaus-Armin Nave
- Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Christian Giaume
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, 75231 Paris Cedex 05, France
| | - Bruno Weber
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland.
| | - Aiman S Saab
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland.
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31
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Connexin 43 gap junction-mediated astrocytic network reconstruction attenuates isoflurane-induced cognitive dysfunction in mice. J Neuroinflammation 2022; 19:64. [PMID: 35255943 PMCID: PMC8903726 DOI: 10.1186/s12974-022-02424-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Accepted: 02/23/2022] [Indexed: 01/18/2023] Open
Abstract
Background Postoperative cognitive dysfunction (POCD) is a common complication following anesthesia and surgery. General anesthetic isoflurane has potential neurotoxicity and induces cognitive impairments, but the exact mechanism remains unclear. Astrocytes form interconnected networks in the adult brain through gap junctions (GJs), which primarily comprise connexin 43 (Cx43), and play important roles in brain homeostasis and functions such as memory. However, the role of the GJ-Cx43-mediated astrocytic network in isoflurane-induced cognitive dysfunction has not been defined. Methods 4-month-old male C57BL/6 mice were exposure to long-term isoflurane to induce cognitive impairment. To simulate an in vitro isoflurane-induced cognitive dysfunction‐like condition, primary mouse astrocytes were subjected to long-term isoflurane exposure. Cognitive function was assessed by Y-maze and fear conditioning tests. Western blot was used to determine the expression levels of different functional configurations of Cx43. The morphology of the GJs-Cx43 was evaluated by immunofluorescence staining. Levels of IL-1β and IL-6 were examined by ELISA. The ability of GJs-Cx43-mediated intercellular communication was examined by lucifer yellow dye transfer assay. Ethidium bromide uptake assays were used to measure the activity of Cx43 hemichannels. The ultrastructural morphology of astrocyte gap junctions and tripartite synapse were observed by transmission electron microscopy. Results After long-term isoflurane anesthesia, the GJs formed by Cx43 in the mouse hippocampus and primary mouse astrocytes were significantly reduced, GJs function was impaired, hemichannel activity was enhanced, the levels of IL-1β and IL-6 were increased, and mice showed significant cognitive impairment. After treatment with the novel GJ-Cx43 enhancer ZP1609, GJ-Cx43-mediated astrocytic network function was enhanced, neuroinflammation was alleviated, and ameliorated cognition dysfunction induced by long-term isoflurane exposure. However, ZP1609 enhances the astrocytic network by promoting Cx43 to form GJs without affecting hemichannel activity. Additionally, our data showed that long-term isoflurane exposure does not alter the structure of tripartite synapse. Conclusion Our results reveal a novel mechanism of the GJ-Cx43-mediated astrocytic network involved in isoflurane-induced neuroinflammation and cognitive impairments, which provides new mechanistic insight into the pathogenesis of POCD and identifies potential targets for its treatment. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-022-02424-y.
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Linsambarth S, Carvajal FJ, Moraga‐Amaro R, Mendez L, Tamburini G, Jimenez I, Verdugo DA, Gómez GI, Jury N, Martínez P, Zundert B, Varela‐Nallar L, Retamal MA, Martin C, Altenberg GA, Fiori MC, Cerpa W, Orellana JA, Stehberg J. Astroglial gliotransmitters released via Cx43 hemichannels regulate NMDAR‐dependent transmission and short‐term fear memory in the basolateral amygdala. FASEB J 2022; 36:e22134. [DOI: 10.1096/fj.202100798rr] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 12/16/2021] [Accepted: 12/17/2021] [Indexed: 11/11/2022]
Affiliation(s)
- Sergio Linsambarth
- Laboratorio de Neurobiología Instituto de Ciencias Biomédicas Facultad de Medicina y Facultad de Ciencias de la Vida Universidad Andres Bello Santiago Chile
| | - Francisco J. Carvajal
- Laboratorio de Función y Patología Neuronal Departamento de Biología Celular y Molecular Facultad de Ciencias Biológicas Pontificia Universidad Católica de Chile Santiago Chile
| | - Rodrigo Moraga‐Amaro
- Laboratorio de Neurobiología Instituto de Ciencias Biomédicas Facultad de Medicina y Facultad de Ciencias de la Vida Universidad Andres Bello Santiago Chile
| | - Luis Mendez
- Laboratorio de Neurobiología Instituto de Ciencias Biomédicas Facultad de Medicina y Facultad de Ciencias de la Vida Universidad Andres Bello Santiago Chile
| | - Giovanni Tamburini
- Laboratorio de Neurobiología Instituto de Ciencias Biomédicas Facultad de Medicina y Facultad de Ciencias de la Vida Universidad Andres Bello Santiago Chile
| | - Ivanka Jimenez
- Laboratorio de Neurobiología Instituto de Ciencias Biomédicas Facultad de Medicina y Facultad de Ciencias de la Vida Universidad Andres Bello Santiago Chile
| | - Daniel Antonio Verdugo
- Laboratorio de Neurobiología Instituto de Ciencias Biomédicas Facultad de Medicina y Facultad de Ciencias de la Vida Universidad Andres Bello Santiago Chile
| | - Gonzalo I. Gómez
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud Universidad Autónoma de Chile Santiago Chile
| | - Nur Jury
- Instituto de Ciencias Biomédicas Facultad de Medicina y Facultad de Ciencias de la Vida Universidad Andres Bello Santiago Chile
| | - Pablo Martínez
- Instituto de Ciencias Biomédicas Facultad de Medicina y Facultad de Ciencias de la Vida Universidad Andres Bello Santiago Chile
| | - Brigitte Zundert
- Instituto de Ciencias Biomédicas Facultad de Medicina y Facultad de Ciencias de la Vida Universidad Andres Bello Santiago Chile
| | - Lorena Varela‐Nallar
- Instituto de Ciencias Biomédicas Facultad de Medicina y Facultad de Ciencias de la Vida Universidad Andres Bello Santiago Chile
| | - Mauricio A. Retamal
- Centro de Fisiología Celular e Integrativa. Facultad de Medicina Clínica Alemana Universidad del Desarrollo Santiago Chile
| | - Claire Martin
- Unité de Biologie Fonctionnelle et Adaptative Centre National la Recherche Scientifique Unité Mixte de Recherche 8251 Université Paris Diderot, Sorbonne Paris Cité Paris France
| | - Guillermo A. Altenberg
- Department of Cell Physiology and Molecular Biophysics Center for Membrane Protein Research Texas Tech University Health Sciences Center Lubbock Texas USA
| | - Mariana C. Fiori
- Department of Cell Physiology and Molecular Biophysics Center for Membrane Protein Research Texas Tech University Health Sciences Center Lubbock Texas USA
| | - Waldo Cerpa
- Laboratorio de Función y Patología Neuronal Departamento de Biología Celular y Molecular Facultad de Ciencias Biológicas Pontificia Universidad Católica de Chile Santiago Chile
| | - Juan A. Orellana
- Departamento de Neurología Escuela de Medicina Pontificia Universidad Católica de Chile Santiago Chile
| | - Jimmy Stehberg
- Laboratorio de Neurobiología Instituto de Ciencias Biomédicas Facultad de Medicina y Facultad de Ciencias de la Vida Universidad Andres Bello Santiago Chile
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Mulkey DK, Olsen ML, Ou M, Cleary CM, Du G. Putative Roles of Astrocytes in General Anesthesia. Curr Neuropharmacol 2022; 20:5-15. [PMID: 33588730 PMCID: PMC9199541 DOI: 10.2174/1570159x19666210215120755] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/29/2021] [Accepted: 02/06/2021] [Indexed: 02/08/2023] Open
Abstract
General anesthetics are a mainstay of modern medicine, and although much progress has been made towards identifying molecular targets of anesthetics and neural networks contributing to endpoints of general anesthesia, our understanding of how anesthetics work remains unclear. Reducing this knowledge gap is of fundamental importance to prevent unwanted and life-threatening side-effects associated with general anesthesia. General anesthetics are chemically diverse, yet they all have similar behavioral endpoints, and so for decades, research has sought to identify a single underlying mechanism to explain how anesthetics work. However, this effort has given way to the 'multiple target hypothesis' as it has become clear that anesthetics target many cellular proteins, including GABAA receptors, glutamate receptors, voltage-independent K+ channels, and voltagedependent K+, Ca2+ and Na+ channels, to name a few. Yet, despite evidence that astrocytes are capable of modulating multiple aspects of neural function and express many anesthetic target proteins, they have been largely ignored as potential targets of anesthesia. The purpose of this brief review is to highlight the effects of anesthetic on astrocyte processes and identify potential roles of astrocytes in behavioral endpoints of anesthesia (hypnosis, amnesia, analgesia, and immobilization).
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Affiliation(s)
- Daniel K. Mulkey
- Department of Physiology and Neurobiology, University of Connecticut, StorrsCT, USA;,Address correspondence to this author at the Department of Physiology and Neurobiology, University of Connecticut, Storrs CT, USA; E-mail:
| | | | | | - Colin M. Cleary
- Department of Physiology and Neurobiology, University of Connecticut, StorrsCT, USA
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Tao XD, Liu ZR, Zhang YQ, Zhang XH. Connexin43 hemichannels contribute to working memory and excitatory synaptic transmission of pyramidal neurons in the prefrontal cortex of rats. Life Sci 2021; 286:120049. [PMID: 34662549 DOI: 10.1016/j.lfs.2021.120049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 10/08/2021] [Accepted: 10/08/2021] [Indexed: 11/30/2022]
Abstract
The gap junction is essential for the communication between astrocytes and neurons by various connexins. Connexin43 hemichannels (Cx43 HCs), one of important subunits of gap junction protein, is highly expressed in astrocytes. It has been demonstrated that Cx43 HCs is involved in synaptic plasticity and learning and memory. However, whether the role of Cx43 HCs in the prefrontal cortex (PFC), a key brain region mediating cognitive and executive functions including working memory, still remains unclear. Here, we investigate that the role of Cx43 HCs in working memory through pharmacological inhibition of Cx43 HCs in the PFC. Gap26, a specific hemichannels blocker for Cx43 HCs, was bilaterally infused into the prelimbic (PrL) area of the PFC and then spatial working memory was examined in delayed alternation task in T-maze. Furthermore, the effect of Gap26 on synaptic transmission of prefrontal pyramidal neurons was examined using whole-cell patch recording in slice containing PFC. The demonstrate that inhibition of prefrontal cortex Cx43 HCs impairs the working memory and excitatory synaptic transmission of PFC neurons, suggesting that Cx43 HCs in the PFC contributes to working memory and excitatory synaptic transmission of neurons in rats.
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Affiliation(s)
- Xiao-Dong Tao
- Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Zhao-Rui Liu
- Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Yu-Qiu Zhang
- Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Xue-Han Zhang
- Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China.
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35
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Akther S, Hirase H. Assessment of astrocytes as a mediator of memory and learning in rodents. Glia 2021; 70:1484-1505. [PMID: 34582594 DOI: 10.1002/glia.24099] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 09/15/2021] [Accepted: 09/16/2021] [Indexed: 12/26/2022]
Abstract
The classical view of astrocytes is that they provide supportive functions for neurons, transporting metabolites and maintaining the homeostasis of the extracellular milieu. This view is gradually changing with the advent of molecular genetics and optical methods allowing interrogation of selected cell types in live experimental animals. An emerging view that astrocytes additionally act as a mediator of synaptic plasticity and contribute to learning processes has gained in vitro and in vivo experimental support. Here we focus on the literature published in the past two decades to review the roles of astrocytes in brain plasticity in rodents, whereby the roles of neurotransmitters and neuromodulators are considered to be comparable to those in humans. We outline established inputs and outputs of astrocytes and discuss how manipulations of astrocytes have impacted the behavior in various learning paradigms. Multiple studies suggest that the contribution of astrocytes has a considerably longer time course than neuronal activation, indicating metabolic roles of astrocytes. We advocate that exploring upstream and downstream mechanisms of astrocytic activation will further provide insight into brain plasticity and memory/learning impairment.
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Affiliation(s)
- Sonam Akther
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hajime Hirase
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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36
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Association Between Adenosine A 2A Receptors and Connexin 43 Regulates Hemichannels Activity and ATP Release in Astrocytes Exposed to Amyloid-β Peptides. Mol Neurobiol 2021; 58:6232-6248. [PMID: 34476674 DOI: 10.1007/s12035-021-02538-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 08/17/2021] [Indexed: 12/31/2022]
Abstract
Increasing evidence implicates astrocytes and the associated purinergic modulation in Alzheimer's disease (AD), characterized by cognitive deficits involving the extracellular amyloid-β peptides (Aβ) accumulation. Aβ can affect astrocytic gliotransmitters release, namely ATP, which is rapidly metabolized into adenosine by ecto-5'-nucleotidase, CD73, resulting in adenosine A2A receptors (A2AR) activation that bolsters neurodegeneration. AD's brains exhibit an upregulation of A2AR and of connexin 43 (Cx43), which in astrocytes forms hemichannels that can mediate ATP release. However, a coupling between astrocytic A2AR and Cx43 remains to be established. This was now investigated using astrocytic primary cultures exposed to Aβ1-42 peptides. Aβ triggered ATP release through Cx43 hemichannels, a process blocked by A2AR antagonists and mimicked by selective A2AR activation. A2AR directly regulated hemichannels activity and prevented Cx43 upregulation and phosphorylation observed in Aβ1-42-exposed astrocytes. Moreover, a proximity ligand assay revealed a physical association between astrocytic A2AR and Cx43. Finally, the blockade of CD73-mediated extracellular formation of ATP-derived adenosine prevented the Aβ-induced increase of Cx43 hemichannel activity and of ATP release. Overall, the data identify a feed-forward loop involving astrocytic A2AR and Cx43 hemichannels, whereby A2AR increase Cx43 hemichannel activity leading to increased ATP release, which is converted into adenosine by CD73, sustaining the increased astrocytic A2AR activity in AD-like conditions.
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Prieto-Villalobos J, Alvear TF, Liberona A, Lucero CM, Martínez-Araya CJ, Balmazabal J, Inostroza CA, Ramírez G, Gómez GI, Orellana JA. Astroglial Hemichannels and Pannexons: The Hidden Link between Maternal Inflammation and Neurological Disorders. Int J Mol Sci 2021; 22:ijms22179503. [PMID: 34502412 PMCID: PMC8430734 DOI: 10.3390/ijms22179503] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 08/30/2021] [Accepted: 08/30/2021] [Indexed: 12/11/2022] Open
Abstract
Maternal inflammation during pregnancy causes later-in-life alterations of the offspring’s brain structure and function. These abnormalities increase the risk of developing several psychiatric and neurological disorders, including schizophrenia, intellectual disability, bipolar disorder, autism spectrum disorder, microcephaly, and cerebral palsy. Here, we discuss how astrocytes might contribute to postnatal brain dysfunction following maternal inflammation, focusing on the signaling mediated by two families of plasma membrane channels: hemi-channels and pannexons. [Ca2+]i imbalance linked to the opening of astrocytic hemichannels and pannexons could disturb essential functions that sustain astrocytic survival and astrocyte-to-neuron support, including energy and redox homeostasis, uptake of K+ and glutamate, and the delivery of neurotrophic factors and energy-rich metabolites. Both phenomena could make neurons more susceptible to the harmful effect of prenatal inflammation and the experience of a second immune challenge during adulthood. On the other hand, maternal inflammation could cause excitotoxicity by producing the release of high amounts of gliotransmitters via astrocytic hemichannels/pannexons, eliciting further neuronal damage. Understanding how hemichannels and pannexons participate in maternal inflammation-induced brain abnormalities could be critical for developing pharmacological therapies against neurological disorders observed in the offspring.
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Affiliation(s)
- Juan Prieto-Villalobos
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.P.-V.); (T.F.A.); (A.L.); (C.J.M.-A.); (J.B.); (C.A.I.); (G.R.)
| | - Tanhia F. Alvear
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.P.-V.); (T.F.A.); (A.L.); (C.J.M.-A.); (J.B.); (C.A.I.); (G.R.)
| | - Andrés Liberona
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.P.-V.); (T.F.A.); (A.L.); (C.J.M.-A.); (J.B.); (C.A.I.); (G.R.)
| | - Claudia M. Lucero
- Institute of Biomedical Sciences, Faculty of Health Sciences, Universidad Autónoma de Chile, Santiago 8910060, Chile; (C.M.L.); (G.I.G.)
| | - Claudio J. Martínez-Araya
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.P.-V.); (T.F.A.); (A.L.); (C.J.M.-A.); (J.B.); (C.A.I.); (G.R.)
| | - Javiera Balmazabal
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.P.-V.); (T.F.A.); (A.L.); (C.J.M.-A.); (J.B.); (C.A.I.); (G.R.)
| | - Carla A. Inostroza
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.P.-V.); (T.F.A.); (A.L.); (C.J.M.-A.); (J.B.); (C.A.I.); (G.R.)
| | - Gigliola Ramírez
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.P.-V.); (T.F.A.); (A.L.); (C.J.M.-A.); (J.B.); (C.A.I.); (G.R.)
| | - Gonzalo I. Gómez
- Institute of Biomedical Sciences, Faculty of Health Sciences, Universidad Autónoma de Chile, Santiago 8910060, Chile; (C.M.L.); (G.I.G.)
| | - Juan A. Orellana
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; (J.P.-V.); (T.F.A.); (A.L.); (C.J.M.-A.); (J.B.); (C.A.I.); (G.R.)
- Correspondence: ; Tel.: +56-23548105
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Retamal MA, Fernandez-Olivares A, Stehberg J. Over-activated hemichannels: A possible therapeutic target for human diseases. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166232. [PMID: 34363932 DOI: 10.1016/j.bbadis.2021.166232] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 07/21/2021] [Accepted: 07/26/2021] [Indexed: 12/14/2022]
Abstract
In our body, all the cells are constantly sharing chemical and electrical information with other cells. This intercellular communication allows them to respond in a concerted way to changes in the extracellular milieu. Connexins are transmembrane proteins that have the particularity of forming two types of channels; hemichannels and gap junction channels. Under normal conditions, hemichannels allow the controlled release of signaling molecules to the extracellular milieu. However, under certain pathological conditions, over-activated hemichannels can induce and/or exacerbate symptoms. In the last decade, great efforts have been put into developing new tools that can modulate these over-activated hemichannels. Small molecules, antibodies and mimetic peptides have shown a potential for the treatment of human diseases. In this review, we summarize recent findings in the field of hemichannel modulation via specific tools, and how these tools could improve patient outcome in certain pathological conditions.
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Affiliation(s)
- Mauricio A Retamal
- Universidad del Desarrollo, Programa de Comunicación Celular en Cáncer, Santiago, Chile; Universidad del Desarrollo, Centro de Fisiología Celular e Integrativa, Santiago, Chile.
| | | | - Jimmy Stehberg
- Laboratorio de Neurobiología, Instituto de Ciencias Biomédicas, Facultad de medicina y Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago, Chile
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Turovsky EA, Varlamova EG. Mechanism of Ca 2+-Dependent Pro-Apoptotic Action of Selenium Nanoparticles, Mediated by Activation of Cx43 Hemichannels. BIOLOGY 2021; 10:biology10080743. [PMID: 34439975 PMCID: PMC8389560 DOI: 10.3390/biology10080743] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/29/2021] [Accepted: 07/30/2021] [Indexed: 12/31/2022]
Abstract
To date, there are practically no data on the mechanisms of the selenium nanoparticles action on calcium homeostasis, intracellular signaling in cancer cells, and on the relationship of signaling pathways activated by an increase in Ca2+ in the cytosol with the induction of apoptosis, which is of great importance. The study of these mechanisms is important for understanding the cytotoxic effect of selenium nanoparticles and the role of this microelement in the regulation of carcinogenesis. The work is devoted to the study of the role of selenium nanoparticles obtained by laser ablation in the activation of the calcium signaling system and the induction of apoptosis in human glioblastoma cells (A-172 cell line). In this work, it was shown for the first time that the generation of Ca2+ signals in A-172 cells occurs in response to the application of various concentrations of selenium nanoparticles. The intracellular mechanism responsible for the generation of these Ca2+ signals has also been established. It was found that nanoparticles promote the mobilization of Ca2+ ions from the endoplasmic reticulum through the IP3-receptor. This leads to the activation of vesicular release of ATP through connexin hemichannels (Cx43) and paracrine cell activation through purinergic receptors (mainly P2Y). In addition, it was shown that the activation of this signaling pathway is accompanied by an increase in the expression of pro-apoptotic genes and the induction of apoptosis. For the first time, the role of Cx43 in the regulation of apoptosis caused by selenium nanoparticles in glioblastoma cells has been shown. It was found that inhibition of Cx43 leads to a significant suppression of the induction of apoptosis in these cells after 24 h treatment of cells with selenium nanoparticles at a concentration of 5 µg/mL.
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Activation of Cx43 Hemichannels Induces the Generation of Ca 2+ Oscillations in White Adipocytes and Stimulates Lipolysis. Int J Mol Sci 2021; 22:ijms22158095. [PMID: 34360859 PMCID: PMC8347185 DOI: 10.3390/ijms22158095] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/22/2021] [Accepted: 07/26/2021] [Indexed: 12/11/2022] Open
Abstract
The aim of the study was to investigate the mechanisms of Ca2+ oscillation generation upon activation of connexin-43 and regulation of the lipolysis/lipogenesis balance in white adipocytes through vesicular ATP release. With fluorescence microscopy it was revealed that a decrease in the concentration of extracellular calcium ([Ca2+]ex) results in two types of Ca2+ responses in white adipocytes: Ca2+ oscillations and transient Ca2+ signals. It was found that activation of the connexin half-channels is involved in the generation of Ca2+ oscillations, since the blockers of the connexin hemichannels-carbenoxolone, octanol, proadifen and Gap26-as well as Cx43 gene knockdown led to complete suppression of these signals. The activation of Cx43 in response to the reduction of [Ca2+]ex was confirmed by TIRF microscopy. It was shown that in response to the activation of Cx43, ATP-containing vesicles were released from the adipocytes. This process was suppressed by knockdown of the Cx43 gene and by bafilomycin A1, an inhibitor of vacuolar ATPase. At the level of intracellular signaling, the generation of Ca2+ oscillations in white adipocytes in response to a decrease in [Ca2+]ex occurred due to the mobilization of the Ca2+ ions from the thapsigargin-sensitive Ca2+ pool of IP3R as a result of activation of the purinergic P2Y1 receptors and phosphoinositide signaling pathway. After activation of Cx43 and generation of the Ca2+ oscillations, changes in the expression levels of key genes and their encoding proteins involved in the regulation of lipolysis were observed in white adipocytes. This effect was accompanied by a decrease in the number of adipocytes containing lipid droplets, while inhibition or knockdown of Cx43 led to inhibition of lipolysis and accumulation of lipid droplets. In this study, we investigated the mechanism of Ca2+ oscillation generation in white adipocytes in response to a decrease in the concentration of Ca2+ ions in the external environment and established an interplay between periodic Ca2+ modes and the regulation of the lipolysis/lipogenesis balance.
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Sherwood MW, Oliet SHR, Panatier A. NMDARs, Coincidence Detectors of Astrocytic and Neuronal Activities. Int J Mol Sci 2021; 22:7258. [PMID: 34298875 PMCID: PMC8307462 DOI: 10.3390/ijms22147258] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/30/2021] [Accepted: 06/30/2021] [Indexed: 12/18/2022] Open
Abstract
Synaptic plasticity is an extensively studied cellular correlate of learning and memory in which NMDARs play a starring role. One of the most interesting features of NMDARs is their ability to act as a co-incident detector. It is unique amongst neurotransmitter receptors in this respect. Co-incident detection is possible because the opening of NMDARs requires membrane depolarisation and the binding of glutamate. Opening of NMDARs also requires a co-agonist. Although the dynamic regulation of glutamate and membrane depolarization have been well studied in coincident detection, the role of the co-agonist site is unexplored. It turns out that non-neuronal glial cells, astrocytes, regulate co-agonist availability, giving them the ability to influence synaptic plasticity. The unique morphology and spatial arrangement of astrocytes at the synaptic level affords them the capacity to sample and integrate information originating from unrelated synapses, regardless of any pre-synaptic and post-synaptic commonality. As astrocytes are classically considered slow responders, their influence at the synapse is widely recognized as modulatory. The aim herein is to reconsider the potential of astrocytes to participate directly in ongoing synaptic NMDAR activity and co-incident detection.
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Affiliation(s)
- Mark W. Sherwood
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France;
| | | | - Aude Panatier
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France;
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Mazaud D, Capano A, Rouach N. The many ways astroglial connexins regulate neurotransmission and behavior. Glia 2021; 69:2527-2545. [PMID: 34101261 DOI: 10.1002/glia.24040] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 05/17/2021] [Accepted: 05/21/2021] [Indexed: 12/18/2022]
Abstract
Astrocytes have emerged as major players in the brain, contributing to many functions such as energy supply, neurotransmission, and behavior. They accomplish these functions in part via their capacity to form widespread intercellular networks and to release neuroactive factors, which can modulate neurotransmission at different levels, from individual synapses to neuronal networks. The extensive network communication of astrocytes is primarily mediated by gap junction channels composed of two connexins, Cx30 and Cx43, which present distinct temporal and spatial expression patterns. Yet, astroglial connexins are also involved in direct exchange with the extracellular space via hemichannels, as well as in adhesion and signaling processes via unconventional nonchannel functions. Accumulating evidence indicate that astrocytes modulate neurotransmission and behavior through these diverse connexin functions. We here review the many ways astroglial connexins regulate neuronal activity from the molecular level to behavior.
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Affiliation(s)
- David Mazaud
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France
| | - Anna Capano
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France.,Doctoral School N°158, Sorbonne University, Paris, France
| | - Nathalie Rouach
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France
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Gunduz-Cinar O. The endocannabinoid system in the amygdala and modulation of fear. Prog Neuropsychopharmacol Biol Psychiatry 2021; 105:110116. [PMID: 32976951 PMCID: PMC7511205 DOI: 10.1016/j.pnpbp.2020.110116] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 09/07/2020] [Accepted: 09/20/2020] [Indexed: 01/01/2023]
Abstract
Posttraumatic stress disorder (PTSD) is a persistent, trauma induced psychiatric condition characterized by lifelong complex cognitive, emotional and behavioral phenotype. Although many individuals that experience trauma are able to gradually diminish their emotional responding to trauma-related stimuli over time, known as extinction learning, individuals suffering from PTSD are impaired in this capacity. An inability to decline this initially normal and adaptive fear response, can be confronted with exposure-based therapies, often in combination with pharmacological treatments. Due to the complexity of PTSD, currently available pharmacotherapeutics are inadequate in treating the deficient extinction observed in many PTSD patients. To develop novel therapeutics, researchers have exploited the conserved nature of fear and stress-associated behavioral responses and neurocircuits across species in an attempt to translate knowledge gained from preclinical studies into the clinic. There is growing evidence on the endocannabinoid modulation of fear and stress due to their 'on demand' synthesis and degradation. Involvement of the endocannabinoids in fear extinction makes the endocannabinoid system very attractive for finding effective therapeutics for trauma and stress related disorders. In this review, a brief introduction on neuroanatomy and circuitry of fear extinction will be provided as a model to study PTSD. Then, the endocannabinoid system will be discussed as an important component of extinction modulation. In this regard, anandamide degrading enzyme, fatty acid amide hydrolase (FAAH) will be exemplified as a target identified and validated strongly from preclinical to clinical translational studies of enhancing extinction.
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Affiliation(s)
- Ozge Gunduz-Cinar
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcoholism and Alcohol Abuse, NIH, Bethesda, MD, USA.
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Hwang SN, Lee JS, Seo K, Lee H. Astrocytic Regulation of Neural Circuits Underlying Behaviors. Cells 2021; 10:cells10020296. [PMID: 33535587 PMCID: PMC7912785 DOI: 10.3390/cells10020296] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/23/2021] [Accepted: 01/29/2021] [Indexed: 02/07/2023] Open
Abstract
Astrocytes, characterized by a satellite-like morphology, are the most abundant type of glia in the central nervous system. Their main functions have been thought to be limited to providing homeostatic support for neurons, but recent studies have revealed that astrocytes actually actively interact with local neural circuits and play a crucial role in information processing and generating physiological and behavioral responses. Here, we review the emerging roles of astrocytes in many brain regions, particularly by focusing on intracellular changes in astrocytes and their interactions with neurons at the molecular and neural circuit levels.
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Affiliation(s)
- Sun-Nyoung Hwang
- Convergence Research Advanced Centre for Olfaction, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea;
| | - Jae Seung Lee
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Korea; (J.S.L.); (K.S.)
| | - Kain Seo
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Korea; (J.S.L.); (K.S.)
| | - Hyosang Lee
- Convergence Research Advanced Centre for Olfaction, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988, Korea;
- Department of Brain and Cognitive Sciences, DGIST, Daegu 42988, Korea; (J.S.L.); (K.S.)
- Korea Brain Research Institute (KBRI), Daegu 41062, Korea
- Correspondence: ; Tel.: +82-53-785-6147
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Abstract
Animal behavior was classically considered to be determined exclusively by neuronal activity, whereas surrounding glial cells such as astrocytes played only supportive roles. However, astrocytes are as numerous as neurons in the mammalian brain, and current findings indicate a chemically based dialog between astrocytes and neurons. Activation of astrocytes by synaptically released neurotransmitters converges on regulating intracellular Ca2+ in astrocytes, which then can regulate the efficacy of near and distant tripartite synapses at diverse timescales through gliotransmitter release. Here, we discuss recent evidence on how diverse behaviors are impacted by this dialog. These recent findings support a paradigm shift in neuroscience, in which animal behavior does not result exclusively from neuronal activity but from the coordinated activity of both astrocytes and neurons. Decoding how astrocytes and neurons interact with each other in various brain circuits will be fundamental to fully understanding how behaviors originate and become dysregulated in disease.
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Affiliation(s)
- Paulo Kofuji
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, USA;
| | - Alfonso Araque
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, USA;
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Mesnil M, Defamie N, Naus C, Sarrouilhe D. Brain Disorders and Chemical Pollutants: A Gap Junction Link? Biomolecules 2020; 11:biom11010051. [PMID: 33396565 PMCID: PMC7824109 DOI: 10.3390/biom11010051] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/22/2020] [Accepted: 12/23/2020] [Indexed: 02/07/2023] Open
Abstract
The incidence of brain pathologies has increased during last decades. Better diagnosis (autism spectrum disorders) and longer life expectancy (Parkinson's disease, Alzheimer's disease) partly explain this increase, while emerging data suggest pollutant exposures as a possible but still underestimated cause of major brain disorders. Taking into account that the brain parenchyma is rich in gap junctions and that most pollutants inhibit their function; brain disorders might be the consequence of gap-junctional alterations due to long-term exposures to pollutants. In this article, this hypothesis is addressed through three complementary aspects: (1) the gap-junctional organization and connexin expression in brain parenchyma and their function; (2) the effect of major pollutants (pesticides, bisphenol A, phthalates, heavy metals, airborne particles, etc.) on gap-junctional and connexin functions; (3) a description of the major brain disorders categorized as neurodevelopmental (autism spectrum disorders, attention deficit hyperactivity disorders, epilepsy), neurobehavioral (migraines, major depressive disorders), neurodegenerative (Parkinson's and Alzheimer's diseases) and cancers (glioma), in which both connexin dysfunction and pollutant involvement have been described. Based on these different aspects, the possible involvement of pollutant-inhibited gap junctions in brain disorders is discussed for prenatal and postnatal exposures.
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Affiliation(s)
- Marc Mesnil
- Laboratoire STIM, ERL7003 CNRS-Université de Poitiers, 1 rue G. Bonnet–TSA 51 106, 86073 Poitiers, France; (M.M.); (N.D.)
| | - Norah Defamie
- Laboratoire STIM, ERL7003 CNRS-Université de Poitiers, 1 rue G. Bonnet–TSA 51 106, 86073 Poitiers, France; (M.M.); (N.D.)
| | - Christian Naus
- Faculty of Medicine, Department of Cellular & Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T1Z3, Canada;
| | - Denis Sarrouilhe
- Laboratoire de Physiologie Humaine, Faculté de Médecine et Pharmacie, 6 rue de La Milétrie, bât D1, TSA 51115, 86073 Poitiers, France
- Correspondence: ; Tel.: +33-5-49-45-43-58
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Portal B, Guiard BP. [Role of astrocytic connexins in the regulation of extracellular glutamate levels: implication for the treatment of major depressive episodes]. Biol Aujourdhui 2020; 214:71-83. [PMID: 33357364 DOI: 10.1051/jbio/2020008] [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: 06/14/2020] [Indexed: 11/14/2022]
Abstract
Major depression is a psychiatric disorder relying on different neurobiological mechanisms. In particular, a hypersensitivity of the hypothalamic-pituitary-adrenal axis leading to an excess of cortisol in blood and a deficit in monoaminergic neurotransmission have been associated with mood disorders. In keeping with these mechanisms, currently available antidepressant drugs act by increasing the extracellular levels of monoamines in the synaptic cleft. Since the discovery of the rapid and long-lasting antidepressant effects of ketamine, an NMDA receptor antagonist, a growing attention in psychiatry is paid to the pharmacological tools able to attenuate glutamatergic neurotransmission. Astrocytes play an important role in the excitatory/inhibitory balance of the central nervous system through the regulation of glutamate reuptake and secretion. Interestingly, the release of this excitatory amino acid is controlled, at least in part, by plasma membrane proteins (i.e. connexins) that cluster together to form gap junctions or hemichannels. Preclinical evidence suggests that these functional entities play a critical role in emotional behaviour. After a brief overview of the literature on mood disorders and related treatments, this review describes the role of astrocytes and connexins in glutamatergic neurotransmission and major depression. Moreover, we highlight the arguments supporting the therapeutic potential of connexins blockers but also the practical difficulties to target the hemichannels while maintaining gap junctions intact.
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Affiliation(s)
- Benjamin Portal
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, Université de Toulouse, CNRS, 31000 Toulouse, France
| | - Bruno P Guiard
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, Université de Toulouse, CNRS, 31000 Toulouse, France
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Verhoog QP, Holtman L, Aronica E, van Vliet EA. Astrocytes as Guardians of Neuronal Excitability: Mechanisms Underlying Epileptogenesis. Front Neurol 2020; 11:591690. [PMID: 33324329 PMCID: PMC7726323 DOI: 10.3389/fneur.2020.591690] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 10/26/2020] [Indexed: 12/11/2022] Open
Abstract
Astrocytes are key homeostatic regulators in the central nervous system and play important roles in physiology. After brain damage caused by e.g., status epilepticus, traumatic brain injury, or stroke, astrocytes may adopt a reactive phenotype. This process of reactive astrogliosis is important to restore brain homeostasis. However, persistent reactive astrogliosis can be detrimental for the brain and contributes to the development of epilepsy. In this review, we will focus on physiological functions of astrocytes in the normal brain as well as pathophysiological functions in the epileptogenic brain, with a focus on acquired epilepsy. We will discuss the role of astrocyte-related processes in epileptogenesis, including reactive astrogliosis, disturbances in energy supply and metabolism, gliotransmission, and extracellular ion concentrations, as well as blood-brain barrier dysfunction and dysregulation of blood flow. Since dysfunction of astrocytes can contribute to epilepsy, we will also discuss their role as potential targets for new therapeutic strategies.
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Affiliation(s)
- Quirijn P. Verhoog
- Leiden Academic Center for Drug Research, Leiden University, Leiden, Netherlands
- Department of Neuropathology, Amsterdam Neuroscience, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Linda Holtman
- Leiden Academic Center for Drug Research, Leiden University, Leiden, Netherlands
| | - Eleonora Aronica
- Department of Neuropathology, Amsterdam Neuroscience, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
- Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, Netherlands
| | - Erwin A. van Vliet
- Department of Neuropathology, Amsterdam Neuroscience, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
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Astrocytic Connexin43 Channels as Candidate Targets in Epilepsy Treatment. Biomolecules 2020; 10:biom10111578. [PMID: 33233647 PMCID: PMC7699773 DOI: 10.3390/biom10111578] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/17/2020] [Accepted: 11/18/2020] [Indexed: 12/15/2022] Open
Abstract
In epilepsy research, emphasis is put on exploring non-neuronal targets such as astrocytic proteins, since many patients remain pharmacoresistant to current treatments, which almost all target neuronal mechanisms. This paper reviews available data on astrocytic connexin43 (Cx43) signaling in seizures and epilepsy. Cx43 is a widely expressed transmembrane protein and the constituent of gap junctions (GJs) and hemichannels (HCs), allowing intercellular and extracellular communication, respectively. A plethora of research papers show altered Cx43 mRNA levels, protein expression, phosphorylation state, distribution and/or functional coupling in human epileptic tissue and experimental models. Human Cx43 mutations are linked to seizures as well, as 30% of patients with oculodentodigital dysplasia (ODDD), a rare genetic condition caused by mutations in the GJA1 gene coding for Cx43 protein, exhibit neurological symptoms including seizures. Cx30/Cx43 double knock-out mice show increased susceptibility to evoked epileptiform events in brain slices due to impaired GJ-mediated redistribution of K+ and glutamate and display a higher frequency of spontaneous generalized chronic seizures in an epilepsy model. Contradictory, Cx30/Cx43 GJs can traffic nutrients to high-energy demanding neurons and initiate astrocytic Ca2+ waves and hyper synchronization, thereby supporting proconvulsant effects. The general connexin channel blocker carbenoxolone and blockers from the fenamate family diminish epileptiform activity in vitro and improve seizure outcome in vivo. In addition, interventions with more selective peptide inhibitors of HCs display anticonvulsant actions. To conclude, further studies aiming to disentangle distinct roles of HCs and GJs are necessary and tools specifically targeting Cx43 HCs may facilitate the search for novel epilepsy treatments.
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Blockade of Glial Connexin 43 Hemichannels Reduces Food Intake. Cells 2020; 9:cells9112387. [PMID: 33142723 PMCID: PMC7693394 DOI: 10.3390/cells9112387] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 10/20/2020] [Accepted: 10/26/2020] [Indexed: 12/16/2022] Open
Abstract
The metabolic syndrome, which comprises obesity and diabetes, is a major public health problem and the awareness of energy homeostasis control remains an important worldwide issue. The energy balance is finely regulated by the central nervous system (CNS), notably through neuronal networks, located in the hypothalamus and the dorsal vagal complex (DVC), which integrate nutritional, humoral and nervous information from the periphery. The glial cells’ contribution to these processes emerged few year ago. However, its underlying mechanism remains unclear. Glial connexin 43 hemichannels (Cx43 HCs) enable direct exchange with the extracellular space and can regulate neuronal network activity. In the present study, we sought to determine the possible involvement of glial Cx43 HCs in energy balance regulation. We here show that Cx43 is strongly expressed in the hypothalamus and DVC and is associated with glial cells. Remarkably, we observed a close apposition of Cx43 with synaptic elements in both the hypothalamus and DVC. Moreover, the expression of hypothalamic Cx43 mRNA and protein is modulated in response to fasting and diet-induced obesity. Functionally, we found that Cx43 HCs are largely open in the arcuate nucleus (ARC) from acute mice hypothalamic slices under basal condition, and significantly inhibited by TAT-GAP19, a mimetic peptide that specifically blocks Cx43 HCs activity. Moreover, intracerebroventricular (i.c.v.) TAT-GAP19 injection strongly decreased food intake, without further alteration of glycaemia, energy expenditures or locomotor activity. Using the immediate early gene c-Fos expression, we found that i.c.v. TAT-GAP19 injection induced neuronal activation in hypothalamic and brainstem nuclei dedicated to food intake regulation. Altogether, these results suggest a tonic delivery of orexigenic molecules associated with glial Cx43 HCs activity and a possible modulation of this tonus during fasting and obesity.
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