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Kim S, Kubelka NK, LaPorte HM, Krishnamoorthy VR, Singh M. Estradiol and 3β-diol protect female cortical astrocytes by regulating connexin 43 Gap Junctions. Mol Cell Endocrinol 2023; 578:112045. [PMID: 37595662 PMCID: PMC10592012 DOI: 10.1016/j.mce.2023.112045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 08/03/2023] [Accepted: 08/14/2023] [Indexed: 08/20/2023]
Abstract
While estrogens have been described to protect or preserve neuronal function in the face of insults such as oxidative stress, the prevailing mechanistic model would suggest that these steroids exert direct effects on the neurons. However, there is growing evidence that glial cells, such as astrocytes, are key cellular mediators of protection. Noting that connexin 43 (Cx43), a protein highly expressed in astrocytes, plays a key role in mediating inter-cellular communication, we hypothesized that Cx43 is a target of estradiol (E2), and the estrogenic metabolite of DHT, 3β-diol. Additionally, we sought to determine if either or both of these hormones attenuate oxidative stress-induced cytotoxicity by eliciting a reduction in Cx43 expression or inhibition of Cx43 channel permeability. Using primary cortical astrocytes, we found that E2 and 3β-diol were each protective against the mixed metabolic/oxidative insult, iodoacetic acid (IAA). Moreover, these effects were blocked by estrogen receptor antagonists. However, E2 and 3β-diol did not alter Cx43 mRNA levels in astrocytes but did inhibit IAA-induced Cx43 gap junction opening/permeability. Taken together, these data implicate astrocyte Cx43 gap junction as an understudied mediator of the cytoprotective effects of estrogens in the brain. Given the wide breadth of disease states associated with Cx43 function/dysfunction, further understanding the relationship between gonadal steroids and Cx43 channels may contribute to a better understanding of the biological basis for sex differences in various diseases.
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Affiliation(s)
- Seongcheol Kim
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, United States
| | - Nicholas Knesek Kubelka
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, United States
| | - Heather M LaPorte
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, United States
| | - Vignesh R Krishnamoorthy
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, United States
| | - Meharvan Singh
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, United States.
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Mazaud D, Capano A, Rouach N. The many ways astroglial connexins regulate neurotransmission and behavior. Glia 2021; 69:2527-2545. [PMID: 34101261 DOI: 10.1002/glia.24040] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 05/17/2021] [Accepted: 05/21/2021] [Indexed: 12/18/2022]
Abstract
Astrocytes have emerged as major players in the brain, contributing to many functions such as energy supply, neurotransmission, and behavior. They accomplish these functions in part via their capacity to form widespread intercellular networks and to release neuroactive factors, which can modulate neurotransmission at different levels, from individual synapses to neuronal networks. The extensive network communication of astrocytes is primarily mediated by gap junction channels composed of two connexins, Cx30 and Cx43, which present distinct temporal and spatial expression patterns. Yet, astroglial connexins are also involved in direct exchange with the extracellular space via hemichannels, as well as in adhesion and signaling processes via unconventional nonchannel functions. Accumulating evidence indicate that astrocytes modulate neurotransmission and behavior through these diverse connexin functions. We here review the many ways astroglial connexins regulate neuronal activity from the molecular level to behavior.
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Affiliation(s)
- David Mazaud
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France
| | - Anna Capano
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France.,Doctoral School N°158, Sorbonne University, Paris, France
| | - Nathalie Rouach
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS UMR 7241, INSERM U1050, Labex Memolife, PSL Research University, Paris, France
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Patabendige A, Singh A, Jenkins S, Sen J, Chen R. Astrocyte Activation in Neurovascular Damage and Repair Following Ischaemic Stroke. Int J Mol Sci 2021; 22:4280. [PMID: 33924191 PMCID: PMC8074612 DOI: 10.3390/ijms22084280] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 04/11/2021] [Accepted: 04/15/2021] [Indexed: 12/11/2022] Open
Abstract
Transient or permanent loss of tissue perfusion due to ischaemic stroke can lead to damage to the neurovasculature, and disrupt brain homeostasis, causing long-term motor and cognitive deficits. Despite promising pre-clinical studies, clinically approved neuroprotective therapies are lacking. Most studies have focused on neurons while ignoring the important roles of other cells of the neurovascular unit, such as astrocytes and pericytes. Astrocytes are important for the development and maintenance of the blood-brain barrier, brain homeostasis, structural support, control of cerebral blood flow and secretion of neuroprotective factors. Emerging data suggest that astrocyte activation exerts both beneficial and detrimental effects following ischaemic stroke. Activated astrocytes provide neuroprotection and contribute to neurorestoration, but also secrete inflammatory modulators, leading to aggravation of the ischaemic lesion. Astrocytes are more resistant than other cell types to stroke pathology, and exert a regulative effect in response to ischaemia. These roles of astrocytes following ischaemic stroke remain incompletely understood, though they represent an appealing target for neurovascular protection following stroke. In this review, we summarise the astrocytic contributions to neurovascular damage and repair following ischaemic stroke, and explore mechanisms of neuroprotection that promote revascularisation and neurorestoration, which may be targeted for developing novel therapies for ischaemic stroke.
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Affiliation(s)
- Adjanie Patabendige
- Brain Barriers Group, School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW 2321, Australia;
- Priority Research Centre for Stroke and Brain Injury, and Priority Research Centre for Brain & Mental Health, University of Newcastle, Callaghan, NSW 2321, Australia
- Hunter Medical Research Institute, New Lambton Heights, NSW 2305, Australia
- Institute of Infection & Global Health, University of Liverpool, Liverpool L7 3EA, UK
| | - Ayesha Singh
- School of Pharmacy and Bioengineering, Keele University, Staffordshire ST5 5BG, UK;
| | - Stuart Jenkins
- School of Medicine, Keele University, Staffordshire ST5 5BG, UK; (S.J.); (J.S.)
- Neural Tissue Engineering: Keele (NTEK), Keele University, Staffordshire ST5 5BG, UK
| | - Jon Sen
- School of Medicine, Keele University, Staffordshire ST5 5BG, UK; (S.J.); (J.S.)
- Clinical Informatics and Neurosurgery Fellow, The Cleveland Clinic, 33 Grosvenor Square, London SW1X 7HY, UK
| | - Ruoli Chen
- School of Pharmacy and Bioengineering, Keele University, Staffordshire ST5 5BG, UK;
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Gap Junction Channels of Innexins and Connexins: Relations and Computational Perspectives. Int J Mol Sci 2019; 20:ijms20102476. [PMID: 31109150 PMCID: PMC6566657 DOI: 10.3390/ijms20102476] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 05/04/2019] [Accepted: 05/14/2019] [Indexed: 12/16/2022] Open
Abstract
Gap junction (GJ) channels in invertebrates have been used to understand cell-to-cell communication in vertebrates. GJs are a common form of intercellular communication channels which connect the cytoplasm of adjacent cells. Dysregulation and structural alteration of the gap junction-mediated communication have been proven to be associated with a myriad of symptoms and tissue-specific pathologies. Animal models relying on the invertebrate nervous system have exposed a relationship between GJs and the formation of electrical synapses during embryogenesis and adulthood. The modulation of GJs as a therapeutic and clinical tool may eventually provide an alternative for treating tissue formation-related diseases and cell propagation. This review concerns the similarities between Hirudo medicinalis innexins and human connexins from nucleotide and protein sequence level perspectives. It also sets forth evidence of computational techniques applied to the study of proteins, sequences, and molecular dynamics. Furthermore, we propose machine learning techniques as a method that could be used to study protein structure, gap junction inhibition, metabolism, and drug development.
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Yin X, Feng L, Ma D, Yin P, Wang X, Hou S, Hao Y, Zhang J, Xin M, Feng J. Roles of astrocytic connexin-43, hemichannels, and gap junctions in oxygen-glucose deprivation/reperfusion injury induced neuroinflammation and the possible regulatory mechanisms of salvianolic acid B and carbenoxolone. J Neuroinflammation 2018; 15:97. [PMID: 29587860 PMCID: PMC5872583 DOI: 10.1186/s12974-018-1127-3] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 03/12/2018] [Indexed: 02/07/2023] Open
Abstract
Background Glia-mediated neuroinflammation is related to brain injury exacerbation after cerebral ischemia/reperfusion (I/R) injury. Astrocytic hemichannels or gap junctions, which were mainly formed by connexin-43, have been implicated in I/R damage. However, the exact roles of astrocytic hemichannels and gap junction in neuroinflammatory responses induced by I/R injury remain unknown. Methods Primary cultured astrocytes were subjected to OGD/R injury, an in vitro model of I/R injury. Salvianolic acid B (SalB) or carbenoxolone (CBX) were applied for those astrocytes. Besides, Cx43 mimetic peptides Gap19 or Gap26 were also applied during OGD/R injury; Cx43 protein levels were determined by western blot and cytoimmunofluorescene staining, hemichannel activities by Ethidium bromide uptake and ATP concentration detection, and gap junction intercellular communication (GJIC) permeability by parachute assay. Further, astrocyte-conditioned medium (ACM) was collected and incubated with microglia. Meanwhile, ATP or apyrase were applied to explore the role of ATP during OGD/R injury. Microglial activation, M1/M2 phenotypes, and M1/M2-related cytokines were detected. Also, microglia-conditioned medium (MEM) was collected and incubated with astrocytes to further investigate its influence on astrocytic hemichannel activity and GJIC permeability. Lastly, effects of ACM and MCM on neuronal viability were detected by flow cytometry. Results We found that OGD/R induced abnormally opened hemichannels with increased ATP release and EtBr uptake but reduced GJIC permeability. WB tests showed decreased astrocytic plasma membrane’s Cx43, while showing an increase in cytoplasma. Treating OGD/R-injured microglia with ATP or OGD/R-ACM induced further microglial activation and secondary pro-inflammatory cytokine release, with the M1 phenotype predominating. Conversely, astrocytes incubated with OGD/R-MCM exhibited increased hemichannel opening but reduced GJIC coupling. Both SalB and CBX inhibited abnormal astrocytic hemichannel opening and ATP release and switched the activated microglial phenotype from M1 to M2, thus providing effective neuroprotection. Application of Gap19 or Gap26 showed similar results with CBX. We also found that OGD/R injury caused both plasma membrane p-Cx43(Ser265) and p-Src(Tyr416) significantly upregulated; application of SalB may be inhibiting Src kinase and attenuating Cx43 internalization. Meanwhile, CBX treatment induced obviously downregulation of p-Cx43(Ser368) and p-PKC(Ser729) protein levels in plasma membrane. Conclusions We propose a vicious cycle exists between astrocytic hemichannel and microglial activation after OGD/R injury, which would aggravate neuroinflammatory responses and neuronal damage. Astrocytic Cx43, hemichannels, and GJIC play critical roles in OGD/R injury-induced neuroinflammatory responses; treatment differentially targeting astrocytic Cx43, hemichannels, and GJIC may provide novel avenues for therapeutics during cerebral I/R injury. Electronic supplementary material The online version of this article (10.1186/s12974-018-1127-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Xiang Yin
- Department of Neurology and Neuroscience Center, the First Hospital of Jilin University, Changchun, Jilin Province, 130021, People's Republic of China
| | - Liangshu Feng
- Department of Neurology and Neuroscience Center, the First Hospital of Jilin University, Changchun, Jilin Province, 130021, People's Republic of China
| | - Di Ma
- Department of Neurology and Neuroscience Center, the First Hospital of Jilin University, Changchun, Jilin Province, 130021, People's Republic of China
| | - Ping Yin
- Department of Neurology and Neuroscience Center, the First Hospital of Jilin University, Changchun, Jilin Province, 130021, People's Republic of China
| | - Xinyu Wang
- Department of Neurology and Neuroscience Center, the First Hospital of Jilin University, Changchun, Jilin Province, 130021, People's Republic of China
| | - Shuai Hou
- Department of Neurology and Neuroscience Center, the First Hospital of Jilin University, Changchun, Jilin Province, 130021, People's Republic of China
| | - Yulei Hao
- Department of Neurology and Neuroscience Center, the First Hospital of Jilin University, Changchun, Jilin Province, 130021, People's Republic of China
| | - Jingdian Zhang
- Department of Neurology and Neuroscience Center, the First Hospital of Jilin University, Changchun, Jilin Province, 130021, People's Republic of China
| | - Meiying Xin
- Department of Neurology and Neuroscience Center, the First Hospital of Jilin University, Changchun, Jilin Province, 130021, People's Republic of China
| | - Jiachun Feng
- Department of Neurology and Neuroscience Center, the First Hospital of Jilin University, Changchun, Jilin Province, 130021, People's Republic of China.
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