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Uva L, Bruno G, de Curtis M. Activity-dependent extracellular potassium changes in unmyelinated versus myelinated areas in olfactory regions of the isolated female guinea-pig brain. Exp Neurol 2024; 379:114884. [PMID: 38992824 DOI: 10.1016/j.expneurol.2024.114884] [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: 04/15/2024] [Revised: 06/26/2024] [Accepted: 07/08/2024] [Indexed: 07/13/2024]
Abstract
The potassium released in the extracellular space during neuronal activity is rapidly removed by glia and neurons to maintain tissue homeostasis. Oligodendrocyte-derived myelin axonal coating contributes to potassium buffering and is therefore crucial to control brain excitability. We studied activity-dependent extracellular potassium ([K+]o) changes in the piriform cortex (PC), a region that features highly segregated bundles of myelinated and unmyelinated fibers. Four-aminopyridine (4AP; 50 μM) treatment or patterned high-frequency stimulations (hfST) were utilized to generate [K+]o changes measured with potassium-sensitive electrodes in the myelinated lateral olfactory tract (LOT), in the unmyelinated PC layer I and in the myelinated deep PC layers in the ex vivo isolated guinea-pig brain. Seizure-like events induced by 4AP are initiated by the abrupt [K+]o rise in the layer I formed by unmyelinated fibers (Uva et al., 2017). Larger [K+]o shifts occurred in unmyelinated layers compared to the myelinated LOT. LOT hfST that mimicks pre-seizure discharges also generated higher [K+]o changes in unmyelinated PC layer I than in LOT and deep PC layers. The treatment with the Kir4.1 potassium channel blocker BaCl2 (100 μM) enhanced the [K+]o changes generated by hfST in myelinated structures. Our data show that activity-dependent [K+]o changes are intrinsically different in myelinated vs unmyelinated cortical regions. The larger [K+]o shifts generated in unmyelinated structures may represent a vehicle for seizure generation.
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Affiliation(s)
- Laura Uva
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, via Celoria 11/via Amadeo 42, Milano, Italy..
| | - Gaia Bruno
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, via Celoria 11/via Amadeo 42, Milano, Italy.; Dipartimento di Biologia e Biotecnologia, via Forlanini, 6, Università di Pavia, 27100, Pavia, Italy..
| | - Marco de Curtis
- Epilepsy Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, via Celoria 11/via Amadeo 42, Milano, Italy..
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2
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Su Y, Verkhratsky A, Yi C. Targeting connexins: possible game changer in managing neuropathic pain? Trends Mol Med 2024; 30:642-659. [PMID: 38594094 DOI: 10.1016/j.molmed.2024.03.009] [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: 01/23/2024] [Revised: 03/08/2024] [Accepted: 03/18/2024] [Indexed: 04/11/2024]
Abstract
Neuropathic pain is a chronic debilitating condition caused by nerve injury or a variety of diseases. At the core of neuropathic pain lies the aberrant neuronal excitability in the peripheral and/or central nervous system (PNS and CNS). Enhanced connexin expression and abnormal activation of connexin-assembled gap junctional channels are prominent in neuropathic pain along with reactive gliosis, contributing to neuronal hypersensitivity and hyperexcitability. In this review, we delve into the current understanding of how connexin expression and function contribute to the pathogenesis and pathophysiology of neuropathic pain and argue for connexins as potential therapeutic targets for neuropathic pain management.
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Affiliation(s)
- Yixun Su
- Research Centre, Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK; Achucarro Center for Neuroscience, IKERBASQUE, Bilbao, Spain; Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania; Department of Forensic Analytical Toxicology, School of Forensic Medicine, China Medical University, Shenyang, China.
| | - Chenju Yi
- Research Centre, Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, China; Guangdong Provincial Key Laboratory of Brain Function and Disease, Guangzhou, China; Shenzhen Key Laboratory of Chinese Medicine Active substance screening and Translational Research, Shenzhen, China.
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3
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Gómez GI, García-Rodríguez C, Marillán JE, Vergara SA, Alvear TF, Farias-Pasten A, Sáez JC, Retamal MA, Rovegno M, Ortiz FC, Orellana JA. Acute activation of hemichannels by ethanol leads to Ca 2+-dependent gliotransmitter release in astrocytes. Front Cell Dev Biol 2024; 12:1422978. [PMID: 38974144 PMCID: PMC11224458 DOI: 10.3389/fcell.2024.1422978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Accepted: 05/30/2024] [Indexed: 07/09/2024] Open
Abstract
Multiple studies have demonstrated that acute ethanol consumption alters brain function and cognition. Nevertheless, the mechanisms underlying this phenomenon remain poorly understood. Astrocyte-mediated gliotransmission is crucial for hippocampal plasticity, and recently, the opening of hemichannels has been found to play a relevant role in this process. Hemichannels are plasma membrane channels composed of six connexins or seven pannexins, respectively, that oligomerize around a central pore. They serve as ionic and molecular exchange conduits between the cytoplasm and extracellular milieu, allowing the release of various paracrine substances, such as ATP, D-serine, and glutamate, and the entry of ions and other substances, such as Ca2+ and glucose. The persistent and exacerbated opening of hemichannels has been associated with the pathogenesis and progression of several brain diseases for at least three mechanisms. The uncontrolled activity of these channels could favor the collapse of ionic gradients and osmotic balance, the release of toxic levels of ATP or glutamate, cell swelling and plasma membrane breakdown and intracellular Ca2+ overload. Here, we evaluated whether acute ethanol exposure affects the activity of astrocyte hemichannels and the possible repercussions of this phenomenon on cytoplasmatic Ca2+ signaling and gliotransmitter release. Acute ethanol exposure triggered the rapid activation of connexin43 and pannexin1 hemichannels in astrocytes, as measured by time-lapse recordings of ethidium uptake. This heightened activity derived from a rapid rise in [Ca2+]i linked to extracellular Ca2+ influx and IP3-evoked Ca2+ release from intracellular Ca2+ stores. Relevantly, the acute ethanol-induced activation of hemichannels contributed to a persistent secondary increase in [Ca2+]i. The [Ca2+]i-dependent activation of hemichannels elicited by ethanol caused the increased release of ATP and glutamate in astroglial cultures and brain slices. Our findings offer fresh perspectives on the potential mechanisms behind acute alcohol-induced brain abnormalities and propose targeting connexin43 and pannexin1 hemichannels in astrocytes as a promising avenue to prevent deleterious consequences of alcohol consumption.
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Affiliation(s)
- Gonzalo I. Gómez
- Faculty of Health Sciences, Institute of Biomedical Sciences, Universidad Autónoma de Chile, Santiago, Chile
| | - Claudia García-Rodríguez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Instituto de Neurociencia, Universidad de Valparaíso, Valparaíso, Chile
| | - Jesús E. Marillán
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Sergio A. Vergara
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica 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, Santiago, Chile
| | - Arantza Farias-Pasten
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan C. Sáez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Instituto de Neurociencia, Universidad de Valparaíso, Valparaíso, Chile
| | - Mauricio A. Retamal
- Programa de Comunicación Celular en Cancer, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago, Chile
| | - Maximiliano Rovegno
- Departamento de Medicina Intensiva, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Fernando C. Ortiz
- Mechanisms of Myelin Formation and Repair Laboratory, Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Juan A. Orellana
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
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4
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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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Untiet V, Verkhratsky A. How astrocytic chloride modulates brain states. Bioessays 2024; 46:e2400004. [PMID: 38615322 DOI: 10.1002/bies.202400004] [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: 01/11/2024] [Revised: 04/03/2024] [Accepted: 04/04/2024] [Indexed: 04/16/2024]
Abstract
The way the central nervous system (CNS) responds to diverse stimuli is contingent upon the specific brain state of the individual, including sleep and wakefulness. Despite the wealth of readout parameters and data delineating the brain states, the primary mechanisms are yet to be identified. Here we highlight the role of astrocytes, with a specific emphasis on chloride (Cl-) homeostasis as a modulator of brain states. Neuronal activity is regulated by the concentration of ions that determine excitability. Astrocytes, as the CNS homeostatic cells, are recognised for their proficiency in maintaining dynamic homeostasis of ions, known as ionostasis. Nevertheless, the contribution of astrocyte-driven ionostasis to the genesis of brain states or their response to sleep-inducing pharmacological agents has been overlooked. Our objective is to underscore the significance of astrocytic Cl- homeostasis, elucidating how it may underlie the modulation of brain states. We endeavour to contribute to a comprehensive understanding of the interplay between astrocytes and brain states.
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Affiliation(s)
- Verena Untiet
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
| | - Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
- Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
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Tao S, Hulpiau P, Wagner LE, Witschas K, Yule DI, Bultynck G, Leybaert L. IP3RPEP6, a novel peptide inhibitor of IP 3 receptor channels that does not affect connexin-43 hemichannels. Acta Physiol (Oxf) 2024; 240:e14086. [PMID: 38240350 DOI: 10.1111/apha.14086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 10/24/2023] [Accepted: 01/01/2024] [Indexed: 02/24/2024]
Abstract
AIM Inositol 1,4,5-trisphosphate receptors (IP3 Rs) are intracellular Ca2+ -release channels with crucial roles in cell function. Current IP3 R inhibitors suffer from off-target effects and poor selectivity towards the three distinct IP3 R subtypes. We developed a novel peptide inhibitor of IP3 Rs and determined its effect on connexin-43 (Cx43) hemichannels, which are co-activated by IP3 R stimulation. METHODS IP3RPEP6 was developed by in silico molecular docking studies and characterized by on-nucleus patch-clamp experiments of IP3 R2 channels and carbachol-induced IP3 -mediated Ca2+ responses in IP3 R1, 2 or 3 expressing cells, triple IP3 R KO cells and astrocytes. Cx43 hemichannels were studied by patch-clamp and ATP-release approaches, and by inhibition with Gap19 peptide. IP3RPEP6 interactions with IP3 Rs were verified by co-immunoprecipitation and affinity pull-down assays. RESULTS IP3RPEP6 concentration-dependently reduced the open probability of IP3 R2 channels and competitively inhibited IP3 Rs in an IC50 order of IP3 R2 (~3.9 μM) < IP3 R3 (~4.3 μM) < IP3 R1 (~9.0 μM), without affecting Cx43 hemichannels or ryanodine receptors. IP3RPEP6 co-immunoprecipitated with IP3 R2 but not with IP3 R1; interaction with IP3 R3 varied between cell types. The IC50 of IP3RPEP6 inhibition of carbachol-induced Ca2+ responses decreased with increasing cellular Cx43 expression. Moreover, Gap19-inhibition of Cx43 hemichannels significantly reduced the amplitude of the IP3 -Ca2+ responses and strongly increased the EC50 of these responses. Finally, we identified palmitoyl-8G-IP3RPEP6 as a membrane-permeable IP3RPEP6 version allowing extracellular application of the IP3 R-inhibiting peptide. CONCLUSION IP3RPEP6 inhibits IP3 R2/R3 at concentrations that have limited effects on IP3 R1. IP3 R activation triggers hemichannel opening, which strongly affects the amplitude and concentration-dependence of IP3 -triggered Ca2+ responses.
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Affiliation(s)
- Siyu Tao
- Department of Basic and Applied Medical Sciences-Physiology Group, Ghent University, Ghent, Belgium
| | - Paco Hulpiau
- Department of Bio-Medical Sciences, HOWEST University of Applied Sciences (Hogeschool West-Vlaanderen), Bruges, Belgium
| | - Larry E Wagner
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, New York, USA
| | - Katja Witschas
- Department of Basic and Applied Medical Sciences-Physiology Group, Ghent University, Ghent, Belgium
| | - David I Yule
- Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester Medical Center, Rochester, New York, USA
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Molecular Cell Biology, KU Leuven, Leuven, Belgium
| | - Luc Leybaert
- Department of Basic and Applied Medical Sciences-Physiology Group, Ghent University, Ghent, Belgium
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Fukuyama K, Motomura E, Okada M. Age-Dependent Activation of Pannexin1 Function Contributes to the Development of Epileptogenesis in Autosomal Dominant Sleep-related Hypermotor Epilepsy Model Rats. Int J Mol Sci 2024; 25:1619. [PMID: 38338895 PMCID: PMC10855882 DOI: 10.3390/ijms25031619] [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: 01/12/2024] [Revised: 01/23/2024] [Accepted: 01/25/2024] [Indexed: 02/12/2024] Open
Abstract
To explore the processes of epileptogenesis/ictogenesis, this study determined the age-dependent development of the functional abnormalities in astroglial transmission associated with pannexin1-hemichannel using a genetic rat model of autosomal dominant sleep-related hypermotor epilepsy (ADSHE) named 'S286L-TG'. Pannexin1 expression in the plasma membrane of primary cultured cortical astrocytes and the orbitofrontal cortex (OFC), which is an ADSHE focus region, were determined using capillary immunoblotting. Astroglial D-serine releases induced by artificial high-frequency oscillation (HFO)-evoked stimulation, the removal of extracellular Ca2+, and the P2X7 receptor agonist (BzATP) were determined using ultra-high performance liquid chromatography (UHPLC). The expressions of pannexin1 in the plasma membrane fraction of the OFC in S286L-TG at four weeks old were almost equivalent when compared to the wild type. The pannexin1 expression in the OFC of the wild type non-statistically decreased age-dependently, whereas that in S286L-TG significantly increased age-dependently, resulting in relatively increasing pannexin1 expression from the 7- (at the onset of interictal discharge) and 10-week-old (after the ADSHE seizure onset) S286L-TG compared to the wild type. However, no functional abnormalities of astroglial pannexin1 expression or D-serine release through the pannexin1-hemichannels from the cultured astrocytes of S286L-TG could be detected. Acutely HFO-evoked stimulation, such as physiological ripple burst (200 Hz) and epileptogenic fast ripple burst (500 Hz), frequency-dependently increased both pannexin1 expression in the astroglial plasma membrane and astroglial D-serine release. Neither the selective inhibitors of pannexin1-hemichannel (10PANX) nor connexin43-hemichannel (Gap19) affected astroglial D-serine release during the resting stage, whereas HFO-evoked D-serine release was suppressed by both inhibitors. The inhibitory effect of 10PANX on the ripple burst-evoked D-serine release was more predominant than that of Gap19, whereas fast ripple burst-evoked D-serine release was predominantly suppressed by Gap19 rather than 10PANX. Astroglial D-serine release induced by acute exposure to BzATP was suppressed by 10PANX but not by Gap19. These results suggest that physiological ripple burst during the sleep spindle plays important roles in the organization of some components of cognition in healthy individuals, but conversely, it contributes to the initial development of epileptogenesis/ictogenesis in individuals who have ADSHE vulnerability via activation of the astroglial excitatory transmission associated with pannexin1-hemichannels.
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Affiliation(s)
| | | | - Motohiro Okada
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, Tsu 514-8507, Japan; (K.F.); (E.M.)
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Boleti APDA, Cardoso PHDO, Frihling BEF, de Moraes LFRN, Nunes EAC, Mukoyama LTH, Nunes EAC, Carvalho CME, Macedo MLR, Migliolo L. Pathophysiology to Risk Factor and Therapeutics to Treatment Strategies on Epilepsy. Brain Sci 2024; 14:71. [PMID: 38248286 PMCID: PMC10813806 DOI: 10.3390/brainsci14010071] [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: 12/18/2023] [Revised: 12/30/2023] [Accepted: 01/06/2024] [Indexed: 01/23/2024] Open
Abstract
Epilepsy represents a condition in which abnormal neuronal discharges or the hyperexcitability of neurons occur with synchronicity, presenting a significant public health challenge. Prognostic factors, such as etiology, electroencephalogram (EEG) abnormalities, the type and number of seizures before treatment, as well as the initial unsatisfactory effects of medications, are important considerations. Although there are several third-generation antiepileptic drugs currently available, their multiple side effects can negatively affect patient quality of life. The inheritance and etiology of epilepsy are complex, involving multiple underlying genetic and epigenetic mechanisms. Different neurotransmitters play crucial roles in maintaining the normal physiology of different neurons. Dysregulations in neurotransmission, due to abnormal transmitter levels or changes in their receptors, can result in seizures. In this review, we address the roles played by various neurotransmitters and their receptors in the pathophysiology of epilepsy. Furthermore, we extensively explore the neurological mechanisms involved in the development and progression of epilepsy, along with its risk factors. Furthermore, we highlight the new therapeutic targets, along with pharmacological and non-pharmacological strategies currently employed in the treatment of epileptic syndromes, including drug interventions employed in clinical trials related to epilepsy.
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Affiliation(s)
- Ana Paula de Araújo Boleti
- S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande 79117-900, Brazil; (A.P.d.A.B.); (P.H.d.O.C.); (B.E.F.F.); (L.F.R.N.d.M.); (E.A.C.N.); (L.T.H.M.); (E.A.C.N.); (C.M.E.C.)
- Laboratório de Purificação de Proteínas e Suas Funções Biológicas, Unidade de Tecnologia de Alimentos e da Saúde Pública, Universidade Federal de Mato Grosso do Sul, Campo Grande 79070-900, Brazil;
| | - Pedro Henrique de Oliveira Cardoso
- S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande 79117-900, Brazil; (A.P.d.A.B.); (P.H.d.O.C.); (B.E.F.F.); (L.F.R.N.d.M.); (E.A.C.N.); (L.T.H.M.); (E.A.C.N.); (C.M.E.C.)
| | - Breno Emanuel Farias Frihling
- S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande 79117-900, Brazil; (A.P.d.A.B.); (P.H.d.O.C.); (B.E.F.F.); (L.F.R.N.d.M.); (E.A.C.N.); (L.T.H.M.); (E.A.C.N.); (C.M.E.C.)
| | - Luiz Filipe Ramalho Nunes de Moraes
- S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande 79117-900, Brazil; (A.P.d.A.B.); (P.H.d.O.C.); (B.E.F.F.); (L.F.R.N.d.M.); (E.A.C.N.); (L.T.H.M.); (E.A.C.N.); (C.M.E.C.)
| | - Ellynes Amancio Correia Nunes
- S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande 79117-900, Brazil; (A.P.d.A.B.); (P.H.d.O.C.); (B.E.F.F.); (L.F.R.N.d.M.); (E.A.C.N.); (L.T.H.M.); (E.A.C.N.); (C.M.E.C.)
- Programa de Pós-graduação em Bioquímica, Universidade Federal do Rio Grande do Norte, Natal 59078-970, Brazil
| | - Lincoln Takashi Hota Mukoyama
- S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande 79117-900, Brazil; (A.P.d.A.B.); (P.H.d.O.C.); (B.E.F.F.); (L.F.R.N.d.M.); (E.A.C.N.); (L.T.H.M.); (E.A.C.N.); (C.M.E.C.)
| | - Ellydberto Amancio Correia Nunes
- S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande 79117-900, Brazil; (A.P.d.A.B.); (P.H.d.O.C.); (B.E.F.F.); (L.F.R.N.d.M.); (E.A.C.N.); (L.T.H.M.); (E.A.C.N.); (C.M.E.C.)
- Programa de Pós-graduação em Bioquímica, Universidade Federal do Rio Grande do Norte, Natal 59078-970, Brazil
| | - Cristiano Marcelo Espinola Carvalho
- S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande 79117-900, Brazil; (A.P.d.A.B.); (P.H.d.O.C.); (B.E.F.F.); (L.F.R.N.d.M.); (E.A.C.N.); (L.T.H.M.); (E.A.C.N.); (C.M.E.C.)
| | - Maria Lígia Rodrigues Macedo
- Laboratório de Purificação de Proteínas e Suas Funções Biológicas, Unidade de Tecnologia de Alimentos e da Saúde Pública, Universidade Federal de Mato Grosso do Sul, Campo Grande 79070-900, Brazil;
| | - Ludovico Migliolo
- S-Inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande 79117-900, Brazil; (A.P.d.A.B.); (P.H.d.O.C.); (B.E.F.F.); (L.F.R.N.d.M.); (E.A.C.N.); (L.T.H.M.); (E.A.C.N.); (C.M.E.C.)
- Programa de Pós-graduação em Bioquímica, Universidade Federal do Rio Grande do Norte, Natal 59078-970, Brazil
- Programa de Pós-graduação em Biologia Celular e Molecular, Universidade Federal da Paraíba, João Pessoa 58051-900, Brazil
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9
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Fiori MC, Altenberg GA. Purification, Reconstitution, and Functional Analysis of Connexin Hemichannels. Methods Mol Biol 2024; 2801:1-16. [PMID: 38578409 DOI: 10.1007/978-1-0716-3842-2_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
Connexins are the proteins that form the gap junction channels that are essential for cell-to-cell communication. These channels are formed by head-to-head docking of hemichannels (each from one of two adjacent cells). Free "undocked" hemichannels at the plasma membrane are mostly closed, although they are still important under physiological conditions. However, abnormal and sustained increase in hemichannel activity due to connexin mutations or acquired conditions can produce or contribute to cell damage. For example, mutations of Cx26, a connexin isoform, can increase hemichannel activity and cause deafness. Studies using purified isolated systems under well-controlled conditions are essential for a full understanding of molecular mechanisms of hemichannel function under normal conditions and in disease, and here, we present methodology for the expression, purification, and functional analysis of hemichannels formed by Cx26.
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Affiliation(s)
- Mariana C Fiori
- Clinical Research Institute, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Guillermo A Altenberg
- Department of Cell Physiology and Molecular Biophysics, and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
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10
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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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11
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Yamasaki R. Connexins Control Glial Inflammation in Various Neurological Diseases. Int J Mol Sci 2023; 24:16879. [PMID: 38069203 PMCID: PMC10706219 DOI: 10.3390/ijms242316879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 11/25/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023] Open
Abstract
Connexins (Cxs) form gap junctions through homotypic/heterotypic oligomerization. Cxs are initially synthesized in the endoplasmic reticulum, then assembled as hexamers in the Golgi apparatus before being integrated into the cell membrane as hemichannels. These hemichannels remain closed until they combine to create gap junctions, directly connecting neighboring cells. Changes in the intracellular or extracellular environment are believed to trigger the opening of hemichannels, creating a passage between the inside and outside of the cell. The size of the channel pore depends on the Cx isoform and cellular context-specific effects such as posttranslational modifications. Hemichannels allow various bioactive molecules, under ~1 kDa, to move in and out of the host cell in the direction of the electrochemical gradient. In this review, we explore the fundamental roles of Cxs and their clinical implications in various neurological dysfunctions, including hereditary diseases, ischemic brain disorders, degenerative conditions, demyelinating disorders, and psychiatric illnesses. The influence of Cxs on the pathomechanisms of different neurological disorders varies depending on the circumstances. Hemichannels are hypothesized to contribute to proinflammatory effects by releasing ATP, adenosine, glutamate, and other bioactive molecules, leading to neuroglial inflammation. Modulating Cxs' hemichannels has emerged as a promising therapeutic approach.
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Affiliation(s)
- Ryo Yamasaki
- Department of Neurology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
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12
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Wang H, Yang X, Lai H, Sun Y, Yan X, Ai Q, Lin M, Yang S, Yang Y, Chu S, Wang Z, Chen N. Novel antidepressant mechanism of hypericin: Role of connexin 43-based gap junctions. Biomed Pharmacother 2023; 167:115545. [PMID: 37734259 DOI: 10.1016/j.biopha.2023.115545] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 09/13/2023] [Accepted: 09/18/2023] [Indexed: 09/23/2023] Open
Abstract
Hypericin is widely utilized for its precise antidepressant properties, but its exact antidepressant mechanism remains unclear. Gap junctions, which were predominantly expressed in astrocytes in the central nervous system, are concerned with the pathogenesis of depression. However, the role of hypericin in gap junctional dysfunction in depression has rarely been investigated. Here, we found that gap junctions were ultra-structurally broadened in the chronic unpredictable stress (CUS) rat model of depression, while hypericin repaired the dysfunction of gap junctions. Suppression of gap junctions by bilateral injection of carbenoxolone (CBX) in the prefrontal cortex of rats significantly inhibited the restoration of gap junctional dysfunction in depression by hypericin. Meanwhile, hypericin failed to show antidepressant benefits. Furthermore, in corticosterone (CORT)-stimulated primary astrocytes derived from neonatal rats, hypericin dramatically reversed the phosphorylation of connexin 43 (Cx43), normalizing the expression of Cx43 and thereby ameliorating gap junctional dysfunction. Comparatively, CBX inhibited the remission of hypericin on gap junctional intercellular communication function. Gap junctional function might be a novel therapeutic target for hypericin in the treatment of depression and provide potential novel insights into the antidepressant mechanism of other herbal ingredients.
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Affiliation(s)
- Huiqin Wang
- Hunan University of Chinese Medicine & Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, Changsha 410208, Hunan, China; 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
| | - Xueying Yang
- School of Chinese Materia Medica, Guangdong Pharmaceutical University, Guangzhou 510006, Guangdong, China
| | - Huaqing Lai
- Science and Technology Innovation Center, Guangzhou University of Chinese Medicine, Guangzhou 510405, Guangdong, China
| | - Yang Sun
- Hunan University of Chinese Medicine & Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, Changsha 410208, Hunan, China
| | - Xu Yan
- 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
| | - Qidi Ai
- Hunan University of Chinese Medicine & Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, Changsha 410208, Hunan, China
| | - Meiyu Lin
- Hunan University of Chinese Medicine & Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, Changsha 410208, Hunan, China
| | - Songwei Yang
- Hunan University of Chinese Medicine & Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, Changsha 410208, Hunan, China
| | - Yantao Yang
- Hunan University of Chinese Medicine & Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, Changsha 410208, Hunan, China
| | - Shifeng Chu
- 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
| | - Zhenzhen 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.
| | - Naihong Chen
- Hunan University of Chinese Medicine & Hunan Engineering Technology Center of Standardization and Function of Chinese Herbal Decoction Pieces, Changsha 410208, Hunan, China; 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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13
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Eitelmann S, Everaerts K, Petersilie L, Rose CR, Stephan J. Ca 2+-dependent rapid uncoupling of astrocytes upon brief metabolic stress. Front Cell Neurosci 2023; 17:1151608. [PMID: 37886111 PMCID: PMC10598858 DOI: 10.3389/fncel.2023.1151608] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 08/23/2023] [Indexed: 10/28/2023] Open
Abstract
Astrocytic gap junctional coupling is a major element in neuron-glia interaction. There is strong evidence that impaired coupling is involved in neurological disorders. Reduced coupling was, e.g., demonstrated for core regions of ischemic stroke that suffer from massive cell death. In the surrounding penumbra, cells may recover, but recovery is hampered by spreading depolarizations, which impose additional metabolic stress onto the tissue. Spreading depolarizations are characterized by transient breakdown of cellular ion homeostasis, including pH and Ca2+, which might directly affect gap junctional coupling. Here, we exposed acute mouse neocortical tissue slices to brief metabolic stress and examined its effects on the coupling strength between astrocytes. Changes in gap junctional coupling were assessed by recordings of the syncytial isopotentiality. Moreover, quantitative ion imaging was performed in astrocytes to analyze the mechanisms triggering the observed changes. Our experiments show that a 2-minute perfusion of tissue slices with blockers of glycolysis and oxidative phosphorylation causes a rapid uncoupling in half of the recorded cells. They further indicate that uncoupling is not mediated by the accompanying (moderate) intracellular acidification. Dampening large astrocytic Ca2+ loads by removal of extracellular Ca2+ or blocking Ca2+ influx pathways as well as a pharmacological inhibition of calmodulin, however, prevent the uncoupling. Taken together, we conclude that astrocytes exposed to brief episodes of metabolic stress can undergo a rapid, Ca2+/calmodulin-dependent uncoupling. Such uncoupling may help to confine and reduce cellular damage in the ischemic penumbra in vivo.
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Affiliation(s)
| | | | | | - Christine R. Rose
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Jonathan Stephan
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
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Li H, Guo A, Salgado M, Sáez JC, Lau CG. The connexin hemichannel inhibitor D4 produces rapid antidepressant-like effects in mice. J Neuroinflammation 2023; 20:191. [PMID: 37599352 PMCID: PMC10440914 DOI: 10.1186/s12974-023-02873-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 08/14/2023] [Indexed: 08/22/2023] Open
Abstract
Depression is a common mood disorder characterized by a range of clinical symptoms, including prolonged low mood and diminished interest. Although many clinical and animal studies have provided significant insights into the pathophysiology of depression, current treatment strategies are not sufficient to manage this disorder. It has been suggested that connexin (Cx)-based hemichannels are candidates for depression intervention by modifying the state of neuroinflammation. In this study, we investigated the antidepressant-like effect of a recently discovered selective Cx hemichannel inhibitor, a small organic molecule called D4. We first showed that D4 reduced hemichannel activity following systemic inflammation after LPS injections. Next, we found that D4 treatment prevented LPS-induced inflammatory response and depressive-like behaviors. These behavioral effects were accompanied by reduced astrocytic activation and hemichannel activity in depressive-like mice induced by repeated low-dose LPS challenges. D4 treatment also reverses depressive-like symptoms in mice subjected to chronic restraint stress (CRS). To test whether D4 broadly affected neural activity, we measured c-Fos expression in depression-related brain regions and found a reduction in c-Fos+ cells in different brain regions. D4 significantly normalized CRS-induced hypoactivation in several brain regions, including the hippocampus, entorhinal cortex, and lateral septum. Together, these results indicate that blocking Cx hemichannels using D4 can normalize neuronal activity and reduce depressive-like symptoms in mice by reducing neuroinflammation. Our work provides evidence of the antidepressant-like effect of D4 and supports glial Cx hemichannels as potential therapeutic targets for depression.
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Affiliation(s)
- Huanhuan Li
- Department of Neuroscience, City University of Hong Kong, Hong Kong SAR, China
- Shenzhen Research Institute, City University of Hong Kong, Shenzhen, China
| | - Anni Guo
- Department of Neuroscience, City University of Hong Kong, Hong Kong SAR, China
- Shenzhen Research Institute, City University of Hong Kong, Shenzhen, China
| | - Magdiel Salgado
- Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, 2381850, Valparaíso, Chile
| | - Juan C Sáez
- Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, 2381850, Valparaíso, Chile
| | - Chunyue Geoffrey Lau
- Department of Neuroscience, City University of Hong Kong, Hong Kong SAR, China.
- Shenzhen Research Institute, City University of Hong Kong, Shenzhen, China.
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15
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Jiménez-Madrona E, Morado-Díaz CJ, Talaverón R, Tabernero A, Pastor AM, Sáez JC, Matarredona ER. Antiproliferative effect of boldine on neural progenitor cells and on glioblastoma cells. Front Neurosci 2023; 17:1211467. [PMID: 37655012 PMCID: PMC10467274 DOI: 10.3389/fnins.2023.1211467] [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: 04/24/2023] [Accepted: 08/02/2023] [Indexed: 09/02/2023] Open
Abstract
Introduction The subventricular zone (SVZ) is a brain region that contains neural stem cells and progenitor cells (NSCs/NPCs) from which new neurons and glial cells are formed during adulthood in mammals. Recent data indicate that SVZ NSCs are the cell type that acquires the initial tumorigenic mutation in glioblastoma (GBM), the most aggressive form of malignant glioma. NSCs/NPCs of the SVZ present hemichannel activity whose function has not yet been fully elucidated. In this work, we aimed to analyze whether hemichannel-mediated communication affects proliferation of SVZ NPCs and GBM cells. Methods and Results For that purpose, we used boldine, an alkaloid derived from the boldo tree (Peumus boldus), that inhibits connexin and pannexin hemichannels, but without affecting gap junctional communication. Boldine treatment (50 μM) of rat SVZ NPCs grown as neurospheres effectively inhibited dye uptake through hemichannels and induced a significant reduction in neurosphere diameter and in bromodeoxyuridine (BrdU) incorporation. However, the differentiation pattern was not modified by the treatment. Experiments with specific blockers for hemichannels formed by connexin subunits (D4) or pannexin 1 (probenecid) revealed that probenecid, but not D4, produced a decrease in BrdU incorporation similar to that obtained with boldine. These results suggest that inhibition of pannexin 1 hemichannels could be partially responsible for the antiproliferative effect of boldine on SVZ NPCs. Analysis of the effect of boldine (25-600 μM) on different types of primary human GBM cells (GBM59, GBM96, and U87-MG) showed a concentration-dependent decrease in GBM cell growth. Boldine treatment also induced a significant inhibition of hemichannel activity in GBM cells. Discussion Altogether, we provide evidence of an antimitotic action of boldine in SVZ NPCs and in GBM cells which may be due, at least in part, to its hemichannel blocking function. These results could be of relevance for future possible strategies in GBM aimed to suppress the proliferation of mutated NSCs or glioma stem cells that might remain in the brain after tumor resection.
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Affiliation(s)
- Enrique Jiménez-Madrona
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, Seville, Spain
- Instituto de Neurociencias de Castilla y León (INCYL), Universidad de Salamanca, Salamanca, Spain
| | - Camilo J. Morado-Díaz
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, Seville, Spain
| | - Rocío Talaverón
- Instituto de Neurociencias de Castilla y León (INCYL), Universidad de Salamanca, Salamanca, Spain
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, Seville, Spain
| | - Arantxa Tabernero
- Instituto de Neurociencias de Castilla y León (INCYL), Universidad de Salamanca, Salamanca, Spain
| | - Angel M. Pastor
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, Seville, Spain
| | - Juan C. Sáez
- Instituto de Neurociencia, Centro Interdisciplinario de Neurociencias de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
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Cao JW, Liu LY, Yu YC. Gap junctions regulate the development of neural circuits in the neocortex. Curr Opin Neurobiol 2023; 81:102735. [PMID: 37263136 DOI: 10.1016/j.conb.2023.102735] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 04/12/2023] [Accepted: 05/07/2023] [Indexed: 06/03/2023]
Abstract
Gap junctions between cells are ubiquitously expressed in the developing brain. They are involved in major steps of neocortical development, including neurogenesis, cell migration, synaptogenesis, and neural circuit formation, and have been implicated in cortical column formation. Dysfunctional gap junctions can contribute to or even cause a variety of brain diseases. Although the role of gap junctions in neocortical development is better known, a comprehensive understanding of their functions is far from complete. Here we explore several critical open questions surrounding gap junctions and their involvement in neural circuit development. Addressing them will greatly impact our understanding of the fundamental mechanisms of neocortical structure and function as well as the etiology of brain disease.
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Affiliation(s)
- Jun-Wei Cao
- School of Basic Medical Sciences, Xiangnan University, Chenzhou, Hunan 423000, China
| | - Lin-Yun Liu
- Jing'an District Central Hospital of Shanghai, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai 200032, China
| | - Yong-Chun Yu
- Jing'an District Central Hospital of Shanghai, State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Institutes of Brain Science, Shanghai 200032, China.
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17
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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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18
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Toro CA, Johnson K, Hansen J, Siddiq MM, Vásquez W, Zhao W, Graham ZA, Sáez JC, Iyengar R, Cardozo CP. Boldine modulates glial transcription and functional recovery in a murine model of contusion spinal cord injury. Front Cell Neurosci 2023; 17:1163436. [PMID: 37416508 PMCID: PMC10321410 DOI: 10.3389/fncel.2023.1163436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 06/01/2023] [Indexed: 07/08/2023] Open
Abstract
Membrane channels such as those formed by connexins (Cx) and P2X7 receptors (P2X7R) are permeable to calcium ions and other small molecules such as adenosine triphosphate (ATP) and glutamate. Release of ATP and glutamate through these channels is a key mechanism driving tissue response to traumas such as spinal cord injury (SCI). Boldine, an alkaloid isolated from the Chilean boldo tree, blocks both Cx and Panx1 hemichannels (HCs). To test if boldine could improve function after SCI, boldine or vehicle was administered to treat mice with a moderate severity contusion-induced SCI. Boldine led to greater spared white matter and increased locomotor function as determined by the Basso Mouse Scale and horizontal ladder rung walk tests. Boldine treatment reduced immunostaining for markers of activated microglia (Iba1) and astrocytic (GFAP) markers while increasing that for axon growth and neuroplasticity (GAP-43). Cell culture studies demonstrated that boldine blocked glial HC, specifically Cx26 and Cx30, in cultured astrocytes and blocked calcium entry through activated P2X7R. RT-qPCR studies showed that boldine treatment reduced expression of the chemokine Ccl2, cytokine IL-6 and microglial gene CD68, while increasing expression of the neurotransmission genes Snap25 and Grin2b, and Gap-43. Bulk RNA sequencing revealed that boldine modulated a large number of genes involved in neurotransmission in spinal cord tissue just caudal from the lesion epicenter at 14 days after SCI. Numbers of genes regulated by boldine was much lower at 28 days after injury. These results indicate that boldine treatment ameliorates injury and spares tissue to increase locomotor function.
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Affiliation(s)
- Carlos A. Toro
- Spinal Cord Damage Research Center, James J. Peters VA Medical Center, Bronx, NY, United States
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Kaitlin Johnson
- Spinal Cord Damage Research Center, James J. Peters VA Medical Center, Bronx, NY, United States
| | - Jens Hansen
- Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Mustafa M. Siddiq
- Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Institute for Systems Biomedicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Walter Vásquez
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile
- Instituto de Neurociencias, Centro Interdisciplinario De Neurociencia De Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Wei Zhao
- Spinal Cord Damage Research Center, James J. Peters VA Medical Center, Bronx, NY, United States
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Zachary A. Graham
- Florida Institute for Human and Machine Cognition, Pensacola, FL, United States
- Department of Cell, Developmental, and Integrative Biology, University of Alabama, Birmingham, AL, United States
- Research Service, Birmingham Veterans Affairs Health Care System, Birmingham, AL, United States
| | - Juan C. Sáez
- Instituto de Neurociencias, Centro Interdisciplinario De Neurociencia De Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Ravi Iyengar
- Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Institute for Systems Biomedicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Christopher P. Cardozo
- Spinal Cord Damage Research Center, James J. Peters VA Medical Center, Bronx, NY, United States
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Rehabilitative Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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19
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Bedner P, Steinhäuser C. Role of Impaired Astrocyte Gap Junction Coupling in Epileptogenesis. Cells 2023; 12:1669. [PMID: 37371139 DOI: 10.3390/cells12121669] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 05/25/2023] [Accepted: 06/19/2023] [Indexed: 06/29/2023] Open
Abstract
The gap-junction-coupled astroglial network plays a central role in the regulation of neuronal activity and synchronisation, but its involvement in the pathogenesis of neuronal diseases is not yet understood. Here, we present the current state of knowledge about the impact of impaired glial coupling in the development and progression of epilepsy and discuss whether astrocytes represent alternative therapeutic targets. We focus mainly on temporal lobe epilepsy (TLE), which is the most common form of epilepsy in adults and is characterised by high therapy resistance. Functional data from TLE patients and corresponding experimental models point to a complete loss of astrocytic coupling, but preservation of the gap junction forming proteins connexin43 and connexin30 in hippocampal sclerosis. Several studies further indicate that astrocyte uncoupling is a causal event in the initiation of TLE, as it occurs very early in epileptogenesis, clearly preceding dysfunctional changes in neurons. However, more research is needed to fully understand the role of gap junction channels in epilepsy and to develop safe and effective therapeutic strategies targeting astrocytes.
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Affiliation(s)
- Peter Bedner
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
| | - Christian Steinhäuser
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
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20
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Cea LA, Vásquez W, Hernández-Salinas R, Vielma AZ, Castillo-Ruiz M, Velarde V, Salgado M, Sáez JC. Skeletal Muscle Atrophy Induced by Diabetes Is Mediated by Non-Selective Channels and Prevented by Boldine. Biomolecules 2023; 13:708. [PMID: 37189454 PMCID: PMC10136059 DOI: 10.3390/biom13040708] [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: 01/31/2023] [Revised: 03/23/2023] [Accepted: 04/04/2023] [Indexed: 05/17/2023] Open
Abstract
Individuals with diabetes mellitus present a skeletal muscle myopathy characterized by atrophy. However, the mechanism underlying this muscular alteration remains elusive, which makes it difficult to design a rational treatment that could avoid the negative consequences in muscles due to diabetes. In the present work, the atrophy of skeletal myofibers from streptozotocin-induced diabetic rats was prevented with boldine, suggesting that non-selective channels inhibited by this alkaloid are involved in this process, as has previously shown for other muscular pathologies. Accordingly, we found a relevant increase in sarcolemma permeability of skeletal myofibers of diabetic animals in vivo and in vitro due to de novo expression of functional connexin hemichannels (Cx HCs) containing connexins (Cxs) 39, 43, and 45. These cells also expressed P2X7 receptors, and their inhibition in vitro drastically reduced sarcolemma permeability, suggesting their participation in the activation of Cx HCs. Notably, sarcolemma permeability of skeletal myofibers was prevented by boldine treatment that blocks Cx43 and Cx45 HCs, and now we demonstrated that it also blocks P2X7 receptors. In addition, the skeletal muscle alterations described above were not observed in diabetic mice with myofibers deficient in Cx43/Cx45 expression. Moreover, murine myofibers cultured for 24 h in high glucose presented a drastic increase in sarcolemma permeability and levels of NLRP3, a molecular member of the inflammasome, a response that was also prevented by boldine, suggesting that, in addition to the systemic inflammatory response found in diabetes, high glucose can promote the expression of functional Cx HCs and activation of the inflammasome in skeletal myofibers. Therefore, Cx43 and Cx45 HCs play a critical role in myofiber degeneration, and boldine could be considered a potential therapeutic agent to treat muscular complications due to diabetes.
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Affiliation(s)
- Luis A. Cea
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Av. Llano Subercaseaux 2801, San Miguel, Santiago 8910060, Chile
| | - Walter Vásquez
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile
| | - Romina Hernández-Salinas
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Universidad del Desarrollo, Santiago 7610000, Chile
| | - Alejandra Z. Vielma
- Escuela de Odontología, Facultad de Medicina Clínica Alemana, Universidad del Desarrollo, Santiago 7610000, Chile
| | - Mario Castillo-Ruiz
- Escuela de Química y Farmacia, Facultad de Medicina, Universidad Andres Bello, Santiago 8370149, Chile
- Departamento de Ciencias Químicas y Biológicas, Facultad de Ciencias de la Salud, Universidad Bernardo O’Higgins, Santiago 8370854, Chile
| | - Victoria Velarde
- Instituto de Fisiología, Universidad de Valparaíso, Valparaíso 2340000, Chile
| | - Magdiel Salgado
- Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, Pasaje Harrington 287, Playa Ancha, Valparaíso 2340000, Chile
| | - Juan C. Sáez
- Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, Pasaje Harrington 287, Playa Ancha, Valparaíso 2340000, Chile
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21
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D'Amico D, Barone R, Di Felice V, Ances B, Prideaux B, Eugenin EA. Chronic brain damage in HIV-infected individuals under antiretroviral therapy is associated with viral reservoirs, sulfatide release, and compromised cell-to-cell communication. Cell Mol Life Sci 2023; 80:116. [PMID: 37016051 PMCID: PMC11071786 DOI: 10.1007/s00018-023-04757-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 03/11/2023] [Accepted: 03/13/2023] [Indexed: 04/06/2023]
Abstract
HIV infection has become a chronic and manageable disease due to the effective use of antiretroviral therapies (ART); however, several chronic aging-related comorbidities, including cognitive impairment, remain a major public health issue. However, these mechanisms are unknown. Here, we identified that glial and myeloid viral reservoirs are associated with local myelin damage and the release of several myelin components, including the lipid sulfatide. Soluble sulfatide compromised gap junctional communication and calcium wave coordination, essential for proper cognition. We propose that soluble sulfatide could be a potential biomarker and contributor to white matter compromise observed in HIV-infected individuals even in the current ART era.
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Affiliation(s)
- Daniela D'Amico
- Department of Neurobiology, The University of Texas Medical Branch (UTMB), Research Building 17, Fifth Floor, 11Th Street, Galveston, TX, 77555, USA
- Department of Biomedicine, Neuroscience, and Advanced Diagnostics (BiND), University of Palermo, Palermo, Italy
| | - Rosario Barone
- Department of Biomedicine, Neuroscience, and Advanced Diagnostics (BiND), University of Palermo, Palermo, Italy
| | - Valentina Di Felice
- Department of Biomedicine, Neuroscience, and Advanced Diagnostics (BiND), University of Palermo, Palermo, Italy
| | - Beau Ances
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Brendan Prideaux
- Department of Neurobiology, The University of Texas Medical Branch (UTMB), Research Building 17, Fifth Floor, 11Th Street, Galveston, TX, 77555, USA.
| | - Eliseo A Eugenin
- Department of Neurobiology, The University of Texas Medical Branch (UTMB), Research Building 17, Fifth Floor, 11Th Street, Galveston, TX, 77555, USA.
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22
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Jaque-Fernandez F, Allard B, Monteiro L, Lafoux A, Huchet C, Jaimovich E, Berthier C, Jacquemond V. Probenecid affects muscle Ca2+ homeostasis and contraction independently from pannexin channel block. J Gen Physiol 2023; 155:e202213203. [PMID: 36820799 PMCID: PMC9998970 DOI: 10.1085/jgp.202213203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 12/21/2022] [Accepted: 02/08/2023] [Indexed: 02/24/2023] Open
Abstract
Tight control of skeletal muscle contractile activation is secured by the excitation-contraction (EC) coupling protein complex, a molecular machinery allowing the plasma membrane voltage to control the activity of the ryanodine receptor Ca2+ release channel in the sarcoplasmic reticulum (SR) membrane. This machinery has been shown to be intimately linked to the plasma membrane protein pannexin-1 (Panx1). We investigated whether the prescription drug probenecid, a widely used Panx1 blocker, affects Ca2+ signaling, EC coupling, and muscle force. The effect of probenecid was tested on membrane current, resting Ca2+, and SR Ca2+ release in isolated mouse muscle fibers, using a combination of whole-cell voltage-clamp and Ca2+ imaging, and on electrically triggered contraction of isolated muscles. Probenecid (1 mM) induces SR Ca2+ leak at rest and reduces peak voltage-activated SR Ca2+ release and contractile force by 40%. Carbenoxolone, another Panx1 blocker, also reduces Ca2+ release, but neither a Panx1 channel inhibitory peptide nor a purinergic antagonist affected Ca2+ release, suggesting that probenecid and carbenoxolone do not act through inhibition of Panx1-mediated ATP release and consequently altered purinergic signaling. Probenecid may act by altering Panx1 interaction with the EC coupling machinery, yet the implication of another molecular target cannot be excluded. Since probenecid has been used both in the clinic and as a masking agent for doping in sports, these results should encourage evaluation of possible effects on muscle function in treated individuals. In addition, they also raise the question of whether probenecid-induced altered Ca2+ homeostasis may be shared by other tissues.
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Affiliation(s)
- Francisco Jaque-Fernandez
- Université Lyon, Université Claude Bernard Lyon 1, CNRS UMR-5261, INSERM U-1315, Institut NeuroMyoGène—Pathophysiology and Genetics of Neuron and Muscle, Lyon, France
| | - Bruno Allard
- Université Lyon, Université Claude Bernard Lyon 1, CNRS UMR-5261, INSERM U-1315, Institut NeuroMyoGène—Pathophysiology and Genetics of Neuron and Muscle, Lyon, France
| | - Laloé Monteiro
- Université Lyon, Université Claude Bernard Lyon 1, CNRS UMR-5261, INSERM U-1315, Institut NeuroMyoGène—Pathophysiology and Genetics of Neuron and Muscle, Lyon, France
| | - Aude Lafoux
- Therassay Platform, CAPACITES, Université de Nantes, Nantes, France
| | - Corinne Huchet
- Therassay Platform, CAPACITES, Université de Nantes, Nantes, France
- Nantes Gene Therapy Laboratory, Université de Nantes, INSERM UMR 1089, Nantes, France
| | - Enrique Jaimovich
- Centro de Estudios Moleculares de la Célula, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Christine Berthier
- Université Lyon, Université Claude Bernard Lyon 1, CNRS UMR-5261, INSERM U-1315, Institut NeuroMyoGène—Pathophysiology and Genetics of Neuron and Muscle, Lyon, France
| | - Vincent Jacquemond
- Université Lyon, Université Claude Bernard Lyon 1, CNRS UMR-5261, INSERM U-1315, Institut NeuroMyoGène—Pathophysiology and Genetics of Neuron and Muscle, Lyon, France
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23
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Koval M, Schug WJ, Isakson BE. Pharmacology of pannexin channels. Curr Opin Pharmacol 2023; 69:102359. [PMID: 36858833 PMCID: PMC10023479 DOI: 10.1016/j.coph.2023.102359] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 01/18/2023] [Accepted: 01/29/2023] [Indexed: 03/02/2023]
Abstract
Pannexin channels play fundamental roles in regulating inflammation and have been implicated in many diseases including hypertension, stroke, and neuropathic pain. Thus, the ability to pharmacologically block these channels is a vital component of several therapeutic approaches. Pharmacologic interrogation of model systems also provides a means to discover new roles for pannexins in cell physiology. Here, we review the state of the art for agents that can be used to block pannexin channels, with a focus on chemical pharmaceuticals and peptide mimetics that act on pannexin 1. Guidance on interpreting results obtained with pannexin pharmacologics in experimental systems is discussed, as well as strengths and caveats of different agents, including specificity and feasibility of clinical application.
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Affiliation(s)
- Michael Koval
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Wyatt J Schug
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Brant E Isakson
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
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24
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Wu X, Li L, Zhou B, Wang J, Shao W. Connexin 43 regulates astrocyte dysfunction and cognitive deficits in early life stress-treated mice. Exp Brain Res 2023; 241:1207-1214. [PMID: 36939885 DOI: 10.1007/s00221-023-06587-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 02/27/2023] [Indexed: 03/21/2023]
Abstract
Early life stress such as maternal separation (MS), is a major risk factor for developing psychiatric disorders in adulthood. Connexin 43 (CX43), the main type of connexins expressed in astrocytes, has been indicated to participate in depression disorders. Nevertheless, the role of CX43 in MS-induced cognitive impairment and astrocyte dysfunction is unclear. Neonatal C57BL/6 mice were exposed to MS to mimic early life stress. Adeno-associated virus carrying CX43 was inoculated into mice for CX43 overexpression. Sucrose preference test, forced swim test and Morris water maze were performed for evaluating depression-like behaviors and spatial learning and memory of mice in adulthood. Real time quantitative polymerase chain reaction was conducted to detect CX43 mRNA expression in mouse brain. Immunofluorescence staining and western blotting were used for measuring expression levels of astrocytic markers in murine hippocampal dentate gyrus. The results showed that overexpressing CX43 attenuated MS exposure-induced depression-like behaviors and decrease in spatial learning and memory in mice. Upregulating CX43 alleviated MS exposure-induced downregulation of astrocytic markers. Collectively, CX43 overexpression attenuates cognitive deficits and astrocyte dysfunction in mice exposed to MS.
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Affiliation(s)
- Xiao Wu
- Department of Neurology, Wuhan First Hospital, Qiaokou District, No. 215 Zhongshan Avenue, Wuhan, 430033, China
| | - Lijuan Li
- Department of Neurology, Wuhan First Hospital, Qiaokou District, No. 215 Zhongshan Avenue, Wuhan, 430033, China
| | - Bingling Zhou
- Department of Neurology, Wuhan First Hospital, Qiaokou District, No. 215 Zhongshan Avenue, Wuhan, 430033, China
| | - Junli Wang
- Department of Neurology, Wuhan First Hospital, Qiaokou District, No. 215 Zhongshan Avenue, Wuhan, 430033, China
| | - Wei Shao
- Department of Neurology, Wuhan First Hospital, Qiaokou District, No. 215 Zhongshan Avenue, Wuhan, 430033, China.
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25
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Leybaert L, De Smet MA, Lissoni A, Allewaert R, Roderick HL, Bultynck G, Delmar M, Sipido KR, Witschas K. Connexin hemichannels as candidate targets for cardioprotective and anti-arrhythmic treatments. J Clin Invest 2023; 133:168117. [PMID: 36919695 PMCID: PMC10014111 DOI: 10.1172/jci168117] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/15/2023] Open
Abstract
Connexins are crucial cardiac proteins that form hemichannels and gap junctions. Gap junctions are responsible for the propagation of electrical and chemical signals between myocardial cells and cells of the specialized conduction system in order to synchronize the cardiac cycle and steer cardiac pump function. Gap junctions are normally open, while hemichannels are closed, but pathological circumstances may close gap junctions and open hemichannels, thereby perturbing cardiac function and homeostasis. Current evidence demonstrates an emerging role of hemichannels in myocardial ischemia and arrhythmia, and tools are now available to selectively inhibit hemichannels without inhibiting gap junctions as well as to stimulate hemichannel incorporation into gap junctions. We review available experimental evidence for hemichannel contributions to cellular pro-arrhythmic events in ventricular and atrial cardiomyocytes, and link these to insights at the level of molecular control of connexin-43-based hemichannel opening. We conclude that a double-edged approach of both preventing hemichannel opening and preserving gap junctional function will be key for further research and development of new connexin-based experimental approaches for treating heart disease.
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Affiliation(s)
- Luc Leybaert
- Physiology Group, Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - Maarten Aj De Smet
- Physiology Group, Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - Alessio Lissoni
- Physiology Group, Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - Rosalie Allewaert
- Physiology Group, Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - H Llewelyn Roderick
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, and
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Mario Delmar
- Leon H. Charney Division of Cardiology, School of Medicine, New York University, New York, USA
| | - Karin R Sipido
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, and
| | - Katja Witschas
- Physiology Group, Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
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26
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Zlomuzica A, Plank L, Kodzaga I, Dere E. A fatal alliance: Glial connexins, myelin pathology and mental disorders. J Psychiatr Res 2023; 159:97-115. [PMID: 36701970 DOI: 10.1016/j.jpsychires.2023.01.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/02/2023] [Accepted: 01/09/2023] [Indexed: 01/12/2023]
Abstract
Mature oligodendrocytes are myelin forming glial cells which are responsible for myelination of neuronal axons in the white matter of the central nervous system. Myelin pathology is a major feature of severe neurological disorders. Oligodendrocyte-specific gene mutations and/or white matter alterations have also been addressed in a variety of mental disorders. Breakdown of myelin integrity and demyelination is associated with severe symptoms, including impairments in motor coordination, breathing, dysarthria, perception (vision and hearing), and cognition. Furthermore, there is evidence indicating that myelin sheath defects and white matter pathology contributes to the affective and cognitive symptoms of patients with mental disorders. Oligodendrocytes express the connexins GJC2; mCx47 [human (GJC2) and mouse (mCx47) connexin gene nomenclature according to Söhl and Willecke (2003)], GJB1; mCx32, and GJD1; mCx29 in both white and gray matter. Preclinical findings indicate that alterations in connexin expression in oligodendrocytes and astrocytes can induce myelin defects. GJC2; mCx47 is expressed at early embryonic stages in oligodendrocyte precursors cells which precedes central nervous system myelination. In adult humans and animals GJC2, respectively mCx47 expression is essential for oligodendrocyte function and ensures adequate myelination as well as myelin maintenance in the central nervous system. In the past decade, evidence has accumulated suggesting that mental disorders can be accompanied by changes in connexin expression, myelin sheath defects and corresponding white matter alterations. This dual pathology could compromise inter-neuronal information transfer, processing and communication and eventually contribute to behavioral, sensory-motor, affective and cognitive symptoms in patients with mental disorders. The induction of myelin repair and remyelination in the central nervous system of patients with mental disorders could help to restore normal neuronal information propagation and ameliorate behavioral and cognitive symptoms in individuals with 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
| | - Iris Kodzaga
- 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, UFR des Sciences de la Vie, 9 quai Saint Bernard, F-75005, Paris, France.
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27
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Peres C, Sellitto C, Nardin C, Putti S, Orsini T, Di Pietro C, Marazziti D, Vitiello A, Calistri A, Rigamonti M, Scavizzi F, Raspa M, Zonta F, Yang G, White TW, Mammano F. Antibody gene transfer treatment drastically improves epidermal pathology in a keratitis ichthyosis deafness syndrome model using male mice. EBioMedicine 2023; 89:104453. [PMID: 36736132 PMCID: PMC9926223 DOI: 10.1016/j.ebiom.2023.104453] [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: 09/23/2022] [Revised: 12/30/2022] [Accepted: 01/11/2023] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Keratitis ichthyosis deafness (KID) syndrome is a rare disorder caused by hemichannel (HC) activating gain-of-function mutations in the GJB2 gene encoding connexin (Cx) 26, for which there is no cure, or current treatments based upon the mechanism of disease causation. METHODS We applied Adeno Associated Virus (AAV) mediated mAb gene transfer (AAVmAb) to treat the epidermal features of KID syndrome with a well-characterized HC blocking antibody using male mice of a murine model that replicates the skin pathology of the human disease. FINDINGS We demonstrate that in vivo AAVmAb treatment significantly reduced the size and thickness of KID lesions, in addition to blocking activity of mutant HCs in the epidermis in vivo. We also show that AAVmAb treatment eliminated abnormal keratinocyte proliferation and enlarged cell size, decreased apoptosis, and restored the normal distribution of keratin expression. INTERPRETATION Our findings reinforce the critical role played by increased HC activity in the skin pathology associated with KID syndrome. They also underscore the clinical potential of anti-HC mAbs coupled with genetic based delivery systems for treating the underlying mechanistic basis of this disorder. Inhibition of HC activity is an ideal therapeutic target in KID syndrome, and the genetic delivery of mAbs targeted against mutant HCs could form the basis of new therapeutic interventions to treat this incurable disease. FUNDING Fondazione Telethon grant GGP19148 and University of Padova grant Prot. BIRD187130 to FM; Foundation for Ichthyosis and Related Skin Types (FIRST) and National Institutes of Health grant EY 026911 to TWW.
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Affiliation(s)
- Chiara Peres
- Institute of Biochemistry and Cell Biology, Italian National Research Council, 00015 Monterotondo, Rome, Italy
| | - Caterina Sellitto
- Department of Physiology and Biophysics, Stony Brook University, T5-147, Basic Science Tower; Stony Brook, NY, 11794-8661, USA
| | - Chiara Nardin
- Institute of Biochemistry and Cell Biology, Italian National Research Council, 00015 Monterotondo, Rome, Italy
| | - Sabrina Putti
- Institute of Biochemistry and Cell Biology, Italian National Research Council, 00015 Monterotondo, Rome, Italy
| | - Tiziana Orsini
- Institute of Biochemistry and Cell Biology, Italian National Research Council, 00015 Monterotondo, Rome, Italy
| | - Chiara Di Pietro
- Institute of Biochemistry and Cell Biology, Italian National Research Council, 00015 Monterotondo, Rome, Italy
| | - Daniela Marazziti
- Institute of Biochemistry and Cell Biology, Italian National Research Council, 00015 Monterotondo, Rome, Italy
| | - Adriana Vitiello
- Department of Molecular Medicine, University of Padova, 35121, Padova, Italy
| | - Arianna Calistri
- Department of Molecular Medicine, University of Padova, 35121, Padova, Italy
| | | | - Ferdinando Scavizzi
- Institute of Biochemistry and Cell Biology, Italian National Research Council, 00015 Monterotondo, Rome, Italy
| | - Marcello Raspa
- Institute of Biochemistry and Cell Biology, Italian National Research Council, 00015 Monterotondo, Rome, Italy
| | - Francesco Zonta
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, 201210, China
| | - Guang Yang
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, 201210, China
| | - Thomas W White
- Department of Physiology and Biophysics, Stony Brook University, T5-147, Basic Science Tower; Stony Brook, NY, 11794-8661, USA.
| | - Fabio Mammano
- Institute of Biochemistry and Cell Biology, Italian National Research Council, 00015 Monterotondo, Rome, Italy; Department of Physics and Astronomy "G. Galilei", University of Padova, 35131, Padova, Italy.
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28
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Peng HR, Zhang YK, Zhou JW. The Structure and Function of Glial Networks: Beyond the Neuronal Connections. Neurosci Bull 2023; 39:531-540. [PMID: 36481974 PMCID: PMC10043088 DOI: 10.1007/s12264-022-00992-w] [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: 05/09/2022] [Accepted: 10/27/2022] [Indexed: 12/13/2022] Open
Abstract
Glial cells, consisting of astrocytes, oligodendrocyte lineage cells, and microglia, account for >50% of the total number of cells in the mammalian brain. They play key roles in the modulation of various brain activities under physiological and pathological conditions. Although the typical morphological features and characteristic functions of these cells are well described, the organization of interconnections of the different glial cell populations and their impact on the healthy and diseased brain is not completely understood. Understanding these processes remains a profound challenge. Accumulating evidence suggests that glial cells can form highly complex interconnections with each other. The astroglial network has been well described. Oligodendrocytes and microglia may also contribute to the formation of glial networks under various circumstances. In this review, we discuss the structure and function of glial networks and their pathological relevance to central nervous system diseases. We also highlight opportunities for future research on the glial connectome.
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Affiliation(s)
- Hai-Rong Peng
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yu-Kai Zhang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jia-Wei Zhou
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China.
- School of Future Technology, University of Chinese Academy of Sciences, Beijing, 100049, China.
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29
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Toro CA, Johnson K, Hansen J, Siddiq MM, Vásquez W, Zhao W, Graham ZA, Sáez JC, Iyengar R, Cardozo CP. Boldine modulates glial transcription and functional recovery in a murine model of contusion spinal cord injury. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.15.528337. [PMID: 36824813 PMCID: PMC9949031 DOI: 10.1101/2023.02.15.528337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Membrane channels such as connexins (Cx), pannexins (Panx) and P2X 7 receptors (P2X 7 R) are permeable to calcium ions and other small molecules such as ATP and glutamate. Release of ATP and glutamate through these channels is a key mechanism driving tissue response to traumas such as spinal cord injury (SCI). Boldine, an alkaloid isolated from the Chilean boldo tree, blocks both Cx hemichannels (HC) and Panx. To test if boldine could improve function after SCI, boldine or vehicle was administered to treat mice with a moderate severity contusion-induced SCI. Boldine led to greater spared white matter and increased locomotor function as determined by the Basso Mouse Scale and horizontal ladder rung walk tests. Boldine treatment reduced immunostaining for markers of activated microglia (Iba1) and astrocytic (GFAP) markers while increasing that for axon growth and neuroplasticity (GAP-43). Cell culture studies demonstrated that boldine blocked glial HC, specifically Cx26 and Cx30, in cultured astrocytes and blocked calcium entry through activated P2X 7 R. RT-qPCR studies showed that boldine treatment reduced expression of the chemokine Ccl2, cytokine IL-6 and microglial gene CD68, while increasing expression of the neurotransmission genes Snap25 and Grin2b, and Gap-43. Bulk RNA sequencing (of the spinal cord revealed that boldine modulated a large number of genes involved in neurotransmission in in spinal cord tissue just below the lesion epicenter at 14 days after SCI. Numbers of genes regulated by boldine was much lower at 28 days after injury. These results indicate that boldine treatment ameliorates injury and spares tissue to increase locomotor function.
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30
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Verkhratsky A, Semyanov A. Astrocytes in Ageing. Subcell Biochem 2023; 103:253-277. [PMID: 37120471 DOI: 10.1007/978-3-031-26576-1_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
Ageing is associated with a morphological and functional decline of astrocytes with a prevalence of morphological atrophy and loss of function. In particular, ageing is manifested by the shrinkage of astrocytic processes: branches and leaflets, which decreases synaptic coverage. Astrocytic dystrophy affects multiple functions astrocytes play in the brain active milieu. In particular, and in combination with an age-dependent decline in the expression of glutamate transporters, astrocytic atrophy translates into deficient glutamate clearance and K+ buffering. Decreased astrocyte presence may contribute to age-dependent remodelling of brain extracellular space, hence affecting extrasynaptic signalling. Old astrocytes lose endfeet polarisation of AQP4 water channels, thus limiting the operation of the glymphatic system. In ageing, astrocytes down-regulate their antioxidant capacity leading to decreased neuroprotection. All these changes may contribute to an age-dependent cognitive decline.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.
- Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
- Department of Neurosciences, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain.
- Department of Forensic Analytical Toxicology, School of Forensic Medicine, China Medical University, Shenyang, China.
- Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania.
| | - Alexey Semyanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
- Sechenov First Moscow State Medical University, Moscow, Russia
- Department of Physiology, Jiaxing University College of Medicine, Jiaxing, Zhejiang Pro, China
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Benedikt J, Malpica-Nieves CJ, Rivera Y, Méndez-González M, Nichols CG, Veh RW, Eaton MJ, Skatchkov SN. The Polyamine Spermine Potentiates the Propagation of Negatively Charged Molecules through the Astrocytic Syncytium. Biomolecules 2022; 12:biom12121812. [PMID: 36551240 PMCID: PMC9775384 DOI: 10.3390/biom12121812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/16/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022] Open
Abstract
The interest in astrocytes, the silent brain cells that accumulate polyamines (PAs), is growing. PAs exert anti-inflammatory, antioxidant, antidepressant, neuroprotective, and other beneficial effects, including increasing longevity in vivo. Unlike neurons, astrocytes are extensively coupled to others via connexin (Cx) gap junctions (GJs). Although there are striking modulatory effects of PAs on neuronal receptors and channels, PA regulation of the astrocytic GJs is not well understood. We studied GJ-propagation using molecules of different (i) electrical charge, (ii) structure, and (iii) molecular weight. Loading single astrocytes with patch pipettes containing membrane-impermeable dyes, we observed that (i) even small molecules do not easily permeate astrocytic GJs, (ii) the ratio of the charge to weight of these molecules is the key determinant of GJ permeation, (iii) the PA spermine (SPM) induced the propagation of negatively charged molecules via GJs, (iv) while no effects were observed on propagation of macromolecules with net-zero charge. The GJ uncoupler carbenoxolone (CBX) blocked such propagation. Taken together, these findings indicate that SPM is essential for astrocytic GJ communication and selectively facilitates intracellular propagation via GJs for negatively charged molecules through glial syncytium.
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Affiliation(s)
- Jan Benedikt
- Department of Physiology, Universidad Central del Caribe, Bayamón, PR 00956, USA
| | - Christian J. Malpica-Nieves
- Department of Biochemistry, Universidad Central del Caribe, Bayamón, PR 00956, USA
- Correspondence: (C.J.M.-N.); (S.N.S.); Tel.: +1-787-798-3001 (ext. 2057) (S.N.S.)
| | - Yomarie Rivera
- Department of Chiropractic, Universidad Central del Caribe, Bayamón, PR 00956, USA
| | | | - Colin G. Nichols
- Department of Cell Biology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Rüdiger W. Veh
- Institut für Zell- und Neurobiologie, Charité, 10115 Berlin, Germany
| | - Misty J. Eaton
- Department of Biochemistry, Universidad Central del Caribe, Bayamón, PR 00956, USA
| | - Serguei N. Skatchkov
- Department of Physiology, Universidad Central del Caribe, Bayamón, PR 00956, USA
- Department of Biochemistry, Universidad Central del Caribe, Bayamón, PR 00956, USA
- Correspondence: (C.J.M.-N.); (S.N.S.); Tel.: +1-787-798-3001 (ext. 2057) (S.N.S.)
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32
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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: 4] [Impact Index Per Article: 2.0] [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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Insulin and IGF-1 elicit robust transcriptional regulation to modulate autophagy in astrocytes. Mol Metab 2022; 66:101647. [PMID: 36503893 PMCID: PMC9731889 DOI: 10.1016/j.molmet.2022.101647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 11/08/2022] [Accepted: 11/23/2022] [Indexed: 11/27/2022] Open
Abstract
OBJECTIVE Insulin is a principal metabolic hormone. It regulates a plethora of metabolic pathways in peripheral tissues. The highly homologous insulin-like growth factor 1 (IGF-1), on the other hand, is important for development and growth. Recent studies have shown that insulin and IGF-1 signaling plays fundamental roles in the brain. Loss of insulin or IGF-1 receptors in astrocytes leads to altered glucose handling, mitochondrial metabolism, neurovascular coupling, and behavioral abnormalities in mice. Here, we aim to investigate molecular mechanisms by which insulin and IGF-1 signaling regulates astrocyte functions. METHODS IR-flox and IRKO primary astrocytes were treated with 100 nM insulin or IGF-1 for 6 h, and their transcriptomes were analyzed. Astrocytes with either IR deletion, IGF1R deletion or both were used to examine receptor-dependent transcriptional regulations using qPCR. Additional immunoblotting and confocal imaging studies were performed to functionally validate pathways involved in protein homeostasis. RESULTS Using next-generation RNA sequencing, we show that insulin significantly regulates the expression of over 1,200 genes involved in multiple functional processes in primary astrocytes. Insulin-like growth factor 1 (IGF-1) triggers a similar robust transcriptional regulation in astrocytes. Thus, over 50% of the differentially expressed genes are regulated by both ligands. As expected, these commonly regulated genes are highly enriched in pathways involved in lipid and cholesterol biosynthesis. Additionally, insulin and IGF-1 induce the expression of genes involved in ribosomal biogenesis, while suppressing the expression of genes involved in autophagy, indicating a common role of insulin and IGF-1 on protein homeostasis in astrocytes. Insulin-dependent suppression of autophagy genes, including p62, Ulk1/2, and several Atg genes, is blunted only when both IR and IGF1R are deleted. CONCLUSIONS In summary, insulin and IGF-1 potently suppress autophagy in astrocytes through transcriptional regulation. Both IR and IGF1R can elicit ligand-dependent transcriptional suppression of autophagy. These results demonstrate an important role of astrocytic insulin/IGF-1 signaling on proteostasis. Impairment of this regulation in insulin resistance and diabetes may contribute to neurological complications related to diabetes.
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34
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Multiple forms of working memory emerge from synapse-astrocyte interactions in a neuron-glia network model. Proc Natl Acad Sci U S A 2022; 119:e2207912119. [PMID: 36256810 PMCID: PMC9618090 DOI: 10.1073/pnas.2207912119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Persistent activity in populations of neurons, time-varying activity across a neural population, or activity-silent mechanisms carried out by hidden internal states of the neural population have been proposed as different mechanisms of working memory (WM). Whether these mechanisms could be mutually exclusive or occur in the same neuronal circuit remains, however, elusive, and so do their biophysical underpinnings. While WM is traditionally regarded to depend purely on neuronal mechanisms, cortical networks also include astrocytes that can modulate neural activity. We propose and investigate a network model that includes both neurons and glia and show that glia-synapse interactions can lead to multiple stable states of synaptic transmission. Depending on parameters, these interactions can lead in turn to distinct patterns of network activity that can serve as substrates for WM.
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35
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Zhang J, Wang T, Zhang Y, Lu P, Shi N, Zhu W, Cai C, He N. Soft integration of a neural cells network and bionic interfaces. Front Bioeng Biotechnol 2022; 10:950235. [PMID: 36246365 PMCID: PMC9558115 DOI: 10.3389/fbioe.2022.950235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Accepted: 09/12/2022] [Indexed: 11/28/2022] Open
Abstract
Both glial cells and neurons can be considered basic computational units in neural networks, and the brain–computer interface (BCI) can play a role in awakening the latency portion and being sensitive to positive feedback through learning. However, high-quality information gained from BCI requires invasive approaches such as microelectrodes implanted under the endocranium. As a hard foreign object in the aqueous microenvironment, the soft cerebral cortex’s chronic inflammation state and scar tissue appear subsequently. To avoid the obvious defects caused by hard electrodes, this review focuses on the bioinspired neural interface, guiding and optimizing the implant system for better biocompatibility and accuracy. At the same time, the bionic techniques of signal reception and transmission interfaces are summarized and the structural units with functions similar to nerve cells are introduced. Multiple electrical and electromagnetic transmissions, regulating the secretion of neuromodulators or neurotransmitters via nanofluidic channels, have been flexibly applied. The accurate regulation of neural networks from the nanoscale to the cellular reconstruction of protein pathways will make BCI the extension of the brain.
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Affiliation(s)
- Jixiang Zhang
- State Key Laboratory of Bioelectronics, National Demonstration Centre for Experimental Biomedical Engineering Education, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
| | - Ting Wang
- State Key Laboratory of Bioelectronics, National Demonstration Centre for Experimental Biomedical Engineering Education, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
- Southeast University Jiangbei New Area Innovation Institute, Nanjing, China
- *Correspondence: Ting Wang,
| | - Yixin Zhang
- State Key Laboratory of Bioelectronics, National Demonstration Centre for Experimental Biomedical Engineering Education, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
| | - Pengyu Lu
- State Key Laboratory of Bioelectronics, National Demonstration Centre for Experimental Biomedical Engineering Education, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
| | - Neng Shi
- State Key Laboratory of Bioelectronics, National Demonstration Centre for Experimental Biomedical Engineering Education, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
| | | | - Chenglong Cai
- State Key Laboratory of Bioelectronics, National Demonstration Centre for Experimental Biomedical Engineering Education, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
- Southeast University Jiangbei New Area Innovation Institute, Nanjing, China
| | - Nongyue He
- State Key Laboratory of Bioelectronics, National Demonstration Centre for Experimental Biomedical Engineering Education, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
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36
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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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37
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Gorina YV, Salmina AB, Erofeev AI, Gerasimov EI, Bolshakova AV, Balaban PM, Bezprozvanny IB, Vlasova OL. Astrocyte Activation Markers. BIOCHEMISTRY. BIOKHIMIIA 2022; 87:851-870. [PMID: 36180985 DOI: 10.1134/s0006297922090012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/27/2022] [Accepted: 06/28/2022] [Indexed: 06/16/2023]
Abstract
Astrocytes are the most common type of glial cells that provide homeostasis and protection of the central nervous system. Important specific characteristic of astrocytes is manifestation of morphological heterogeneity, which is directly dependent on localization in a particular area of the brain. Astrocytes can integrate into neural networks and keep neurons active in various areas of the brain. Moreover, astrocytes express a variety of receptors, channels, and membrane transporters, which underlie their peculiar metabolic activity, and, hence, determine plasticity of the central nervous system during development and aging. Such complex structural and functional organization of astrocytes requires the use of modern methods for their identification and analysis. Considering the important fact that determining the most appropriate marker for polymorphic and multiple subgroups of astrocytes is of decisive importance for studying their multifunctionality, this review presents markers, modern imaging techniques, and identification of astrocytes, which comprise a valuable resource for studying structural and functional properties of astrocytes, as well as facilitate better understanding of the extent to which astrocytes contribute to neuronal activity.
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Affiliation(s)
- Yana V Gorina
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, 194091, Russia.
- Research Institute of Molecular Medicine and Pathobiochemistry, Voino-Yasenetsky Krasnoyarsk State Medical University, Krasnoyarsk, 660022, Russia
| | - Alla B Salmina
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, 194091, Russia
- Research Institute of Molecular Medicine and Pathobiochemistry, Voino-Yasenetsky Krasnoyarsk State Medical University, Krasnoyarsk, 660022, Russia
- Laboratory of Neurobiology and Tissue Engineering, Brain Institute, Research Center of Neurology, Moscow, 105064, Russia
| | - Alexander I Erofeev
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, 194091, Russia
| | - Evgeniy I Gerasimov
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, 194091, Russia
| | - Anastasia V Bolshakova
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, 194091, Russia
| | - Pavel M Balaban
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, 194091, Russia
- Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity, Moscow, 117485, Russia
| | - Ilya B Bezprozvanny
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, 194091, Russia
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Olga L Vlasova
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, 194091, Russia
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38
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Demais V, Pohl A, Wunderlich KA, Pfaller AM, Kaplan L, Barthélémy A, Dittrich R, Puig B, Giebel B, Hauck SM, Pfrieger FW, Grosche A. Release of VAMP5-positive extracellular vesicles by retinal Müller glia in vivo. J Extracell Vesicles 2022; 11:e12254. [PMID: 36043482 PMCID: PMC9428896 DOI: 10.1002/jev2.12254] [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: 04/19/2022] [Revised: 06/25/2022] [Accepted: 07/18/2022] [Indexed: 11/11/2022] Open
Abstract
Cell-cell interactions in the central nervous system are based on the release of molecules mediating signal exchange and providing structural and trophic support through vesicular exocytosis and the formation of extracellular vesicles. The specific mechanisms employed by each cell type in the brain are incompletely understood. Here, we explored the means of communication used by Müller cells, a type of radial glial cells in the retina, which forms part of the central nervous system. Using immunohistochemical, electron microscopic, and molecular analyses, we provide evidence for the release of distinct extracellular vesicles from endfeet and microvilli of retinal Müller cells in adult mice in vivo. We identify VAMP5 as a Müller cell-specific SNARE component that is part of extracellular vesicles and responsive to ischemia, and we reveal differences between the secretomes of immunoaffinity-purified Müller cells and neurons in vitro. Our findings suggest extracellular vesicle-based communication as an important mediator of cellular interactions in the retina.
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Affiliation(s)
- Valerie Demais
- Plateforme Imagerie In Vitro, CNRS UAR 3156, Neuropôle, University of Strasbourg, Strasbourg, France
| | - Anne Pohl
- Department of Physiological Genomics, BioMedical Center BMC, Ludwig-Maximilian University, Planegg-Martinsried, Germany.,Institute of Human Genetics, University of Regensburg, Regensburg, Germany
| | - Kirsten A Wunderlich
- Department of Physiological Genomics, BioMedical Center BMC, Ludwig-Maximilian University, Planegg-Martinsried, Germany
| | - Anna M Pfaller
- Department of Physiological Genomics, BioMedical Center BMC, Ludwig-Maximilian University, Planegg-Martinsried, Germany
| | - Lew Kaplan
- Department of Physiological Genomics, BioMedical Center BMC, Ludwig-Maximilian University, Planegg-Martinsried, Germany
| | - Amelie Barthélémy
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
| | - Robin Dittrich
- Institute for Transfusion Medicine, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Berta Puig
- Neurology Department, Experimental Research in Stroke and Inflammation (ERSI), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Bernd Giebel
- Institute for Transfusion Medicine, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Stefanie M Hauck
- Metabolomics and Proteomics Core and Research Unit Protein Science, Helmholtz-Zentrum München, München, Germany
| | - Frank W Pfrieger
- Plateforme Imagerie In Vitro, CNRS UAR 3156, Neuropôle, University of Strasbourg, Strasbourg, France.,Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France
| | - Antje Grosche
- Department of Physiological Genomics, BioMedical Center BMC, Ludwig-Maximilian University, Planegg-Martinsried, Germany
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Connexins Signatures of the Neurovascular Unit and Their Physio-Pathological Functions. Int J Mol Sci 2022; 23:ijms23179510. [PMID: 36076908 PMCID: PMC9455936 DOI: 10.3390/ijms23179510] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 08/19/2022] [Accepted: 08/21/2022] [Indexed: 11/16/2022] Open
Abstract
Central nervous system (CNS) homeostasis is closely linked to the delicate balance of the microenvironment in which different cellular components of the neurovascular unit (NVU) coexist. Intercellular communication plays a pivotal role in exchanges of signaling molecules and mediators essential for survival functions, as well as in the removal of disturbing elements that can lead to related pathologies. The specific signatures of connexins (Cxs), proteins which form either gap junctions (GJs) or hemichannels (HCs), represent the biological substrate of the pathophysiological balance. Connexin 43 (Cx43) is undoubtedly one of the most important factors in glia–neuro–vascular crosstalk. Herein, Cxs signatures of every NVU component are highlighted and their critical influence on functional processes in healthy and pathological conditions of nervous microenvironment is reviewed.
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40
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Dincã DM, Lallemant L, González-Barriga A, Cresto N, Braz SO, Sicot G, Pillet LE, Polvèche H, Magneron P, Huguet-Lachon A, Benyamine H, Azotla-Vilchis CN, Agonizantes-Juárez LE, Tahraoui-Boris J, Martinat C, Hernández-Hernández O, Auboeuf D, Rouach N, Bourgeois CF, Gourdon G, Gomes-Pereira M. Myotonic dystrophy RNA toxicity alters morphology, adhesion and migration of mouse and human astrocytes. Nat Commun 2022; 13:3841. [PMID: 35789154 PMCID: PMC9253038 DOI: 10.1038/s41467-022-31594-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 06/21/2022] [Indexed: 11/24/2022] Open
Abstract
Brain dysfunction in myotonic dystrophy type 1 (DM1), the prototype of toxic RNA disorders, has been mainly attributed to neuronal RNA misprocessing, while little attention has been given to non-neuronal brain cells. Here, using a transgenic mouse model of DM1 that expresses mutant RNA in various brain cell types (neurons, astroglia, and oligodendroglia), we demonstrate that astrocytes exhibit impaired ramification and polarization in vivo and defects in adhesion, spreading, and migration. RNA-dependent toxicity and phenotypes are also found in human transfected glial cells. In line with the cell phenotypes, molecular analyses reveal extensive expression and accumulation of toxic RNA in astrocytes, which result in RNA spliceopathy that is more severe than in neurons. Astrocyte missplicing affects primarily transcripts that regulate cell adhesion, cytoskeleton, and morphogenesis, and it is confirmed in human brain tissue. Our findings demonstrate that DM1 impacts astrocyte cell biology, possibly compromising their support and regulation of synaptic function. Myotonic dystrophy type 1 (DM1) is characterized by debilitating neurological symptoms. Dinca et al. demonstrate the pronounced impact of DM1 on the morphology and RNA metabolism of astrocytes. Their findings suggest astroglial pathology in DM1 brain dysfunction.
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Affiliation(s)
- Diana M Dincã
- Sorbonne Université, Inserm, Centre de Recherche en Myologie, 75013, Paris, France
| | - Louison Lallemant
- Sorbonne Université, Inserm, Centre de Recherche en Myologie, 75013, Paris, France
| | | | - Noémie Cresto
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS, Inserm, Labex Memolife, 75005, Paris, France
| | - Sandra O Braz
- Sorbonne Université, Inserm, Centre de Recherche en Myologie, 75013, Paris, France.,Inserm UMR1163, Institut Imagine, Université Paris Cite, 75015, Paris, France
| | - Géraldine Sicot
- Sorbonne Université, Inserm, Centre de Recherche en Myologie, 75013, Paris, France
| | - Laure-Elise Pillet
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS, Inserm, Labex Memolife, 75005, Paris, France.,Doctoral School N°562, Paris Descartes University, Paris, 75006, France
| | - Hélène Polvèche
- Inserm/UEVE UMR861, Université Paris Saclay I-STEM, 91110, Corbeil-Essonnes, France
| | - Paul Magneron
- Sorbonne Université, Inserm, Centre de Recherche en Myologie, 75013, Paris, France
| | - Aline Huguet-Lachon
- Sorbonne Université, Inserm, Centre de Recherche en Myologie, 75013, Paris, France
| | - Hélène Benyamine
- Sorbonne Université, Inserm, Centre de Recherche en Myologie, 75013, Paris, France
| | - Cuauhtli N Azotla-Vilchis
- Laboratory of Genomic Medicine, Department of Genetics, National Rehabilitation Institute (INR-LGII), Mexico City, Mexico
| | - Luis E Agonizantes-Juárez
- Laboratory of Genomic Medicine, Department of Genetics, National Rehabilitation Institute (INR-LGII), Mexico City, Mexico
| | - Julie Tahraoui-Boris
- Inserm/UEVE UMR861, Université Paris Saclay I-STEM, 91110, Corbeil-Essonnes, France
| | - Cécile Martinat
- Inserm/UEVE UMR861, Université Paris Saclay I-STEM, 91110, Corbeil-Essonnes, France
| | - Oscar Hernández-Hernández
- Laboratory of Genomic Medicine, Department of Genetics, National Rehabilitation Institute (INR-LGII), Mexico City, Mexico
| | - Didier Auboeuf
- Laboratoire de Biologie et Modelisation de la Cellule, Ecole Normale Superieure de Lyon, CNRS, UMR 5239, Inserm, U1293, Universite Claude Bernard Lyon 1, 46 allée d'Italie, 69364, Lyon, France
| | - Nathalie Rouach
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS, Inserm, Labex Memolife, 75005, Paris, France
| | - Cyril F Bourgeois
- Laboratoire de Biologie et Modelisation de la Cellule, Ecole Normale Superieure de Lyon, CNRS, UMR 5239, Inserm, U1293, Universite Claude Bernard Lyon 1, 46 allée d'Italie, 69364, Lyon, France
| | - Geneviève Gourdon
- Sorbonne Université, Inserm, Centre de Recherche en Myologie, 75013, Paris, France.
| | - Mário Gomes-Pereira
- Sorbonne Université, Inserm, Centre de Recherche en Myologie, 75013, Paris, France.
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Burboa PC, Puebla M, Gaete PS, Durán WN, Lillo MA. Connexin and Pannexin Large-Pore Channels in Microcirculation and Neurovascular Coupling Function. Int J Mol Sci 2022; 23:ijms23137303. [PMID: 35806312 PMCID: PMC9266979 DOI: 10.3390/ijms23137303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 06/27/2022] [Accepted: 06/28/2022] [Indexed: 01/27/2023] Open
Abstract
Microcirculation homeostasis depends on several channels permeable to ions and/or small molecules that facilitate the regulation of the vasomotor tone, hyperpermeability, the blood–brain barrier, and the neurovascular coupling function. Connexin (Cxs) and Pannexin (Panxs) large-pore channel proteins are implicated in several aspects of vascular physiology. The permeation of ions (i.e., Ca2+) and key metabolites (ATP, prostaglandins, D-serine, etc.) through Cxs (i.e., gap junction channels or hemichannels) and Panxs proteins plays a vital role in intercellular communication and maintaining vascular homeostasis. Therefore, dysregulation or genetic pathologies associated with these channels promote deleterious tissue consequences. This review provides an overview of current knowledge concerning the physiological role of these large-pore molecule channels in microcirculation (arterioles, capillaries, venules) and in the neurovascular coupling function.
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Affiliation(s)
- Pía C. Burboa
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, 185 South Orange Avenue, Newark, NJ 07103, USA; (P.C.B.); (W.N.D.)
- Departamento de Morfología y Función, Facultad de Salud y Ciencias Sociales, Sede Santiago Centro, Universidad de las Américas, Avenue República 71, Santiago 8370040, Chile;
| | - Mariela Puebla
- Departamento de Morfología y Función, Facultad de Salud y Ciencias Sociales, Sede Santiago Centro, Universidad de las Américas, Avenue República 71, Santiago 8370040, Chile;
| | - Pablo S. Gaete
- Department of Physiology and Membrane Biology, University of California at Davis, Davis, CA 95616, USA;
| | - Walter N. Durán
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, 185 South Orange Avenue, Newark, NJ 07103, USA; (P.C.B.); (W.N.D.)
- Rutgers School of Graduate Studies, 185 South Orange Avenue, Newark, NJ 07103, USA
| | - Mauricio A. Lillo
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, 185 South Orange Avenue, Newark, NJ 07103, USA; (P.C.B.); (W.N.D.)
- Correspondence:
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A Quantitative Assay for Ca2+ Uptake through Normal and Pathological Hemichannels. Int J Mol Sci 2022; 23:ijms23137337. [PMID: 35806342 PMCID: PMC9266989 DOI: 10.3390/ijms23137337] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 06/26/2022] [Accepted: 06/28/2022] [Indexed: 12/25/2022] Open
Abstract
Connexin (Cx) hemichannels (HCs) are large pore hexameric structures that allow the exchange of ions, metabolites and a variety of other molecules between the cell cytoplasm and extracellular milieu. HC inhibitors are attracting growing interest as drug candidates because deregulated fluxes through HCs have been implicated in a plethora of genetic conditions and other diseases. HC activity has been mainly investigated by electrophysiological methods and/or using HC-permeable dye uptake measurements. Here, we present an all-optical assay based on fluorometric measurements of ionized calcium (Ca2+) uptake with a Ca2+-selective genetically encoded indicator (GCaMP6s) that permits the optical tracking of cytosolic Ca2+ concentration ([Ca2+]cyt) changes with high sensitivity. We exemplify use of the assay in stable pools of HaCaT cells overexpressing human Cx26, Cx46, or the pathological mutant Cx26G45E, under control of a tetracycline (Tet) responsive element (TRE) promoter (Tet-on). We demonstrate the usefulness of the assay for the characterization of new monoclonal antibodies (mAbs) targeting the extracellular domain of the HCs. Although we developed the assay on a spinning disk confocal fluorescence microscope, the same methodology can be extended seamlessly to high-throughput high-content platforms to screen other kinds of inhibitors and/or to probe HCs expressed in primary cells and microtissues.
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Wei H, Moffett JR, Amanat M, Fatemi A, Tsukamoto T, Namboodiri AM, Slusher BS. The pathogenesis of, and pharmacological treatment for, Canavan disease. Drug Discov Today 2022; 27:2467-2483. [DOI: 10.1016/j.drudis.2022.05.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 05/05/2022] [Accepted: 05/24/2022] [Indexed: 12/12/2022]
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Garcia-Martin G, Alcover-Sanchez B, Wandosell F, Cubelos B. Pathways Involved in Remyelination after Cerebral Ischemia. Curr Neuropharmacol 2022; 20:751-765. [PMID: 34151767 PMCID: PMC9878953 DOI: 10.2174/1570159x19666210610093658] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 05/05/2021] [Accepted: 05/12/2021] [Indexed: 11/22/2022] Open
Abstract
Brain ischemia, also known as ischemic stroke, occurs when there is a lack of blood supply into the brain. When an ischemic insult appears, both neurons and glial cells can react in several ways that will determine the severity and prognosis. This high heterogeneity of responses has been a major obstacle in developing effective treatments or preventive methods for stroke. Although white matter pathophysiology has not been deeply assessed in stroke, its remodelling can greatly influence the clinical outcome and the disability degree. Oligodendrocytes, the unique cell type implied in CNS myelination, are sensible to ischemic damage. Loss of myelin sheaths can compromise axon survival, so new Oligodendrocyte Precursor Cells are required to restore brain function. Stroke can, therefore, enhance oligodendrogenesis to regenerate those new oligodendrocytes that will ensheath the damaged axons. Given that myelination is a highly complex process that requires coordination of multiple pathways such as Sonic Hedgehog, RTKs or Wnt/β-catenin, we will analyse new research highlighting their importance after brain ischemia. In addition, oligodendrocytes are not isolated cells inside the brain, but rather form part of a dynamic environment of interactions between neurons and glial cells. For this reason, we will put some context into how microglia and astrocytes react against stroke and influence oligodendrogenesis to highlight the relevance of remyelination in the ischemic brain. This will help to guide future studies to develop treatments focused on potentiating the ability of the brain to repair the damage.
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Affiliation(s)
- Gonzalo Garcia-Martin
- Departamento de Biología Molecular and Centro Biología Molecular “Severo Ochoa”, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
| | - Berta Alcover-Sanchez
- Departamento de Biología Molecular and Centro Biología Molecular “Severo Ochoa”, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
| | - Francisco Wandosell
- Departamento de Biología Molecular and Centro Biología Molecular “Severo Ochoa”, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain
| | - Beatriz Cubelos
- Departamento de Biología Molecular and Centro Biología Molecular “Severo Ochoa”, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain,Address correspondence to this author at the Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Nicolás Cabrera 1, Universidad Autónoma de Madrid, 28049 Madrid, Spain; Tel: 34-91-1964561; Fax: 34-91-1964420; E-mail:
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Rieck J, Skatchkov SN, Derst C, Eaton MJ, Veh RW. Unique Chemistry, Intake, and Metabolism of Polyamines in the Central Nervous System (CNS) and Its Body. Biomolecules 2022; 12:biom12040501. [PMID: 35454090 PMCID: PMC9025450 DOI: 10.3390/biom12040501] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 03/16/2022] [Accepted: 03/17/2022] [Indexed: 02/04/2023] Open
Abstract
Polyamines (PAs) are small, versatile molecules with two or more nitrogen-containing positively charged groups and provide widespread biological functions. Most of these aspects are well known and covered by quite a number of excellent surveys. Here, the present review includes novel aspects and questions: (1) It summarizes the role of most natural and some important synthetic PAs. (2) It depicts PA uptake from nutrition and bacterial production in the intestinal system following loss of PAs via defecation. (3) It highlights the discrepancy between the high concentrations of PAs in the gut lumen and their low concentration in the blood plasma and cerebrospinal fluid, while concentrations in cellular cytoplasm are much higher. (4) The present review provides a novel and complete scheme for the biosynthesis of Pas, including glycine, glutamate, proline and others as PA precursors, and provides a hypothesis that the agmatine pathway may rescue putrescine production when ODC knockout seems to be lethal (solving the apparent contradiction in the literature). (5) It summarizes novel data on PA transport in brain glial cells explaining why these cells but not neurons preferentially accumulate PAs. (6) Finally, it provides a novel and complete scheme for PA interconversion, including hypusine, putreanine, and GABA (unique gliotransmitter) as end-products. Altogether, this review can serve as an updated contribution to understanding the PA mystery.
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Affiliation(s)
- Julian Rieck
- Institut für Zell- und Neurobiologie, Centrum 2, Charité—Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany;
| | - Serguei N. Skatchkov
- Department of Physiology, Universidad Central del Caribe, Bayamón, PR 00956, USA
- Department of Biochemistry, Universidad Central del Caribe, Bayamón, PR 00956, USA;
- Correspondence: (S.N.S.); (R.W.V.)
| | - Christian Derst
- Institut für Integrative Neuroanatomie, Centrum 2, Charité—Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany;
| | - Misty J. Eaton
- Department of Biochemistry, Universidad Central del Caribe, Bayamón, PR 00956, USA;
| | - Rüdiger W. Veh
- Institut für Zell- und Neurobiologie, Centrum 2, Charité—Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany;
- Correspondence: (S.N.S.); (R.W.V.)
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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: 25] [Impact Index Per Article: 12.5] [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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Harcha PA, López-López T, Palacios AG, Sáez PJ. Pannexin Channel Regulation of Cell Migration: Focus on Immune Cells. Front Immunol 2022; 12:750480. [PMID: 34975840 PMCID: PMC8716617 DOI: 10.3389/fimmu.2021.750480] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 11/15/2021] [Indexed: 12/12/2022] Open
Abstract
The role of Pannexin (PANX) channels during collective and single cell migration is increasingly recognized. Amongst many functions that are relevant to cell migration, here we focus on the role of PANX-mediated adenine nucleotide release and associated autocrine and paracrine signaling. We also summarize the contribution of PANXs with the cytoskeleton, which is also key regulator of cell migration. PANXs, as mechanosensitive ATP releasing channels, provide a unique link between cell migration and purinergic communication. The functional association with several purinergic receptors, together with a plethora of signals that modulate their opening, allows PANX channels to integrate physical and chemical cues during inflammation. Ubiquitously expressed in almost all immune cells, PANX1 opening has been reported in different immunological contexts. Immune activation is the epitome coordination between cell communication and migration, as leukocytes (i.e., T cells, dendritic cells) exchange information while migrating towards the injury site. In the current review, we summarized the contribution of PANX channels during immune cell migration and recruitment; although we also compile the available evidence for non-immune cells (including fibroblasts, keratinocytes, astrocytes, and cancer cells). Finally, we discuss the current evidence of PANX1 and PANX3 channels as a both positive and/or negative regulator in different inflammatory conditions, proposing a general mechanism of these channels contribution during cell migration.
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Affiliation(s)
- Paloma A Harcha
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Tamara López-López
- Cell Communication and Migration Laboratory, Institute of Biochemistry and Molecular Cell Biology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Adrián G Palacios
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Pablo J Sáez
- Cell Communication and Migration Laboratory, Institute of Biochemistry and Molecular Cell Biology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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Duan M, Liu Y, Guo D, Kan S, Niu Z, Pu X, Bai M, Zhang D, Du W, Xie J. TGF-β2 increases cell-cell communication in chondrocytes via p-Smad3 signalling. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2022; 1869:119175. [PMID: 34863793 DOI: 10.1016/j.bbamcr.2021.119175] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 11/18/2021] [Accepted: 11/18/2021] [Indexed: 02/08/2023]
Abstract
Connexin 43 (Cx43)-mediated gap junction intercellular communication (GJIC) plays a crucial role in the pathology and physiology of joint tissues. Transforming growth factor-β2 (TGF-β2), one of the potent regulatory factors in chondrocytes, plays a key role in the regulation of cell cycle and development of joint diseases. However, it is still unknown how TGF-β2 mediates GJIC in chondrocytes. The aim of this study was to explore the potential mechanism by which TGF-β2 regulates GJIC in chondrocytes. CCK-8 assays and scratch assays were performed to define the role of TGF-β2 on cell proliferation and migration. The scrape loading/dye transfer assay and scanning electron microscopy (SEM) were used to verify the effect of TGF-β2 on GJIC between chondrocytes. qPCR was performed to analyse the expression of genes in the gap junction protein family in chondrocytes. The expression of the Cx43 protein and phosphorylated Smad3 (p-Smad3) was evaluated by western blot assay. Immunofluorescence staining was used to explore p-Smad3 signalling pathway activation and Cx43 distribution. From these experiments, we found that the Cx43 protein was the most highly expressed member of the gap junction protein family in chondrocytes. We also found that TGF-β2 facilitated cell-to-cell communication in chondrocytes by upregulating Cx43 expression in chondrocytes. Finally, we found that TGF-β2 activated Smad3 signalling and promoted the nuclear aggregation of p-Smad3. Inhibition experiments by SIS3 also confirmed that TGF-β2-mediated GJIC through p-Smad3 signalling. For the first time, this study confirmed that TGF-β2 could regulate the formation of Cx43-mediated GJIC in chondrocytes via the canonical p-Smad3 signalling pathway.
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Affiliation(s)
- Mengmeng Duan
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yang Liu
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Daimo Guo
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Shiyi Kan
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Zhixing Niu
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xiaohua Pu
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Mingru Bai
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610064, China
| | - Demao Zhang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Wei Du
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610064, China.
| | - Jing Xie
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
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Yang S, Kong XY, Hu T, Ge YJ, Li XY, Chen JT, He S, Zhang P, Chen GH. Aquaporin-4, Connexin-30, and Connexin-43 as Biomarkers for Decreased Objective Sleep Quality and/or Cognition Dysfunction in Patients With Chronic Insomnia Disorder. Front Psychiatry 2022; 13:856867. [PMID: 35401278 PMCID: PMC8989729 DOI: 10.3389/fpsyt.2022.856867] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 02/21/2022] [Indexed: 12/04/2022] Open
Abstract
OBJECTIVES To examine serum concentrations of aquaporin-4 (AQP4), connexin-30 (CX30), connexin-43 (CX43), and their correlations with cognitive function in the patients with chronic insomnia disorder (CID). METHODS We enrolled 76 subjects with CID and 32 healthy controls (HCs). Serum levels of AQP4, CX30, and CX43 were measured by enzyme-linked immunosorbent assays. Sleep quality was assessed with the Pittsburgh Sleep Quality Index (PSQI) and polysomnography, and mood was evaluated with 17-item Hamilton Depression Rating Scale and 14-item Hamilton Anxiety Rating Scale. Cognitive function was evaluated by the Chinese-Beijing Version of Montreal Cognitive Assessment (MoCA-C) and Nine Box Maze Test. RESULTS The serum levels of AQP4, CX43, and CX30 were significantly reduced in the CID group compared to the HCs. Partial correlation analysis showed that the biomarkers showed no significant correlations with PSQI score, AHI, ODI and TS90, but AQP4, CX43, and CX30 were positively associated with the percentage and total time of slow wave sleep in the CID group. Serum concentrations of AQP4 and CX30 were positively associated with MoCA-C score in the CID group, and AQP4 level negatively correlated with spatial working memory errors. CONCLUSIONS Subjects with CID patients have decreased serum levels of AQP4, CX30, and CX43 indicating astrocyte dysfunction, which could be related to poor objective sleep quality and/or cognition dysfunction.
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Affiliation(s)
- Shuai Yang
- Department of Neurology (Sleep Disorders), The Affiliated Chaohu Hospital of Anhui Medical University, Hefei, China
| | - Xiao-Yi Kong
- Department of Neurology (Sleep Disorders), The Affiliated Chaohu Hospital of Anhui Medical University, Hefei, China
| | - Ting Hu
- Department of Neurology (Sleep Disorders), The Affiliated Chaohu Hospital of Anhui Medical University, Hefei, China
| | - Yi-Jun Ge
- Department of Neurology (Sleep Disorders), The Affiliated Chaohu Hospital of Anhui Medical University, Hefei, China
| | - Xue-Yan Li
- Department of Neurology (Sleep Disorders), The Affiliated Chaohu Hospital of Anhui Medical University, Hefei, China
| | - Jun-Tao Chen
- Department of Neurology (Sleep Disorders), The Affiliated Chaohu Hospital of Anhui Medical University, Hefei, China
| | - Shuo He
- Department of Neurology (Sleep Disorders), The Affiliated Chaohu Hospital of Anhui Medical University, Hefei, China
| | - Ping Zhang
- Department of Neurology (Sleep Disorders), The Affiliated Chaohu Hospital of Anhui Medical University, Hefei, China
| | - Gui-Hai Chen
- Department of Neurology (Sleep Disorders), The Affiliated Chaohu Hospital of Anhui Medical University, Hefei, China
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Gap Junctions and Hemichannels Composed of Connexins and Pannexins Mediate the Secondary Brain Injury Following Intracerebral Hemorrhage. BIOLOGY 2021; 11:biology11010027. [PMID: 35053024 PMCID: PMC8772966 DOI: 10.3390/biology11010027] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 12/19/2021] [Accepted: 12/24/2021] [Indexed: 12/15/2022]
Abstract
Simple Summary Intracerebral hemorrhage (ICH) is a leading medical problem without effective treatment options. The poor prognosis is attributed to the primary brain injury of the mechanical compression caused by hematoma, and secondary brain injury (SBI) that includes inflammation, glutamate excitotoxicity, oxidative stress and disruption of the blood brain barrier (BBB). Evidences suggests that gap junctions and hemichannels composed of connexins and pannexins regulate the inflammation and excitotoxicity insult in the pathological process of central nervous system disease, such as cerebral ischemia and neurodegeneration disease. In this manuscript, we discuss the fact that connexins- and pannexins-based channels could be involved in secondary brain injury of ICH, particularly through mediating inflammation, oxidative stress, BBB disruption and cell death. The details provided in this manuscript may help develop potential targets for therapeutic intervention of ICH. Abstract Intracerebral hemorrhage (ICH) is a devastating disease with high mortality and morbidity; the mortality rate ranges from 40% at 1 month to 54% at 1 year; only 12–39% achieve good outcomes and functional independence. ICH affects nearly 2 million patients worldwide annually. In ICH development, the blood leakage from ruptured vessels generates sequelae of secondary brain injury (SBI). This mechanism involves activated astrocytes and microglia, generation of reactive oxygen species (ROS), the release of reactive nitrogen species (RNS), and disrupted blood brain barrier (BBB). In addition, inflammatory cytokines and chemokines, heme compounds, and products of hematoma are accumulated in the extracellular spaces, thereby resulting in the death of brain cells. Recent evidence indicates that connexins regulate microglial activation and their phenotypic transformation. Moreover, communications between neurons and glia via gap junctions have crucial roles in neuroinflammation and cell death. A growing body of evidence suggests that, in addition to gap junctions, hemichannels (composed of connexins and pannexins) play a key role in ICH pathogenesis. However, the precise connection between connexin and pannexin channels and ICH remains to be resolved. This review discusses the pathological roles of gap junctions and hemichannels in SBI following ICH, with the intent of discovering effective therapeutic options of strategies to treat ICH.
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