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Skelin L, Racetin A, Kelam N, Ogorevc M, Znaor L, Saraga-Babić M, Filipović N, Katsuyama Y, Pogorelić Z, Vukojević K. Connexin Expression Is Altered in the Eye Development of Yotari Mice: A Preliminary Study. Biomolecules 2024; 14:1174. [PMID: 39334940 PMCID: PMC11430515 DOI: 10.3390/biom14091174] [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: 08/20/2024] [Revised: 09/12/2024] [Accepted: 09/13/2024] [Indexed: 09/30/2024] Open
Abstract
This study aimed to explore how Dab1 functional silencing influences the expression patterns of different connexins in the developing yotari (yot) mice eyes as potential determinants of retinogenesis. Using immunofluorescence staining, the protein expression of Dab1, Reelin, and connexin 37, 40, 43, and 45 (Cx37, Cx40, Cx43, and Cx45) in the wild-type (wt) and yot eyes at embryonic days 13.5 and 15.5 (E13.5 and E15.5) were analyzed. Different expression patterns of Cx37 were seen between the wt and yot groups. The highest fluorescence intensity of Cx37 was observed in the yot animals at E15.5. Cx40 had higher expression at the E13.5 when differentiation of retinal layers was still beginning, whereas it decreased at the E15.5 when differentiation was at the advanced stage. Higher expression of Cx43 was found in the yot group at both time points. Cx45 was predominantly expressed at E13.5 in both groups. Our results reveal the altered expression of connexins during retinogenesis in yot mice and their potential involvement in retinal pathology, where they might serve as prospective therapeutic targets.
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Affiliation(s)
- Ljubica Skelin
- Clinical Department of Ophthalmology, University Hospital of Split, 21000 Split, Croatia
| | - Anita Racetin
- Department of Anatomy, Histology and Embryology, University of Split School of Medicine, Šoltanska 2A, 21000 Split, Croatia
- Center for Translational Research in Biomedicine, University of Split School of Medicine, Šoltanska 2A, 21000 Split, Croatia
| | - Nela Kelam
- Department of Anatomy, Histology and Embryology, University of Split School of Medicine, Šoltanska 2A, 21000 Split, Croatia
- Center for Translational Research in Biomedicine, University of Split School of Medicine, Šoltanska 2A, 21000 Split, Croatia
| | - Marin Ogorevc
- Department of Anatomy, Histology and Embryology, University of Split School of Medicine, Šoltanska 2A, 21000 Split, Croatia
- Center for Translational Research in Biomedicine, University of Split School of Medicine, Šoltanska 2A, 21000 Split, Croatia
| | - Ljubo Znaor
- Clinical Department of Ophthalmology, University Hospital of Split, 21000 Split, Croatia
- Department of Ophthalmology, University of Split School of Medicine, Šoltanska 2A, 21000 Split, Croatia
| | - Mirna Saraga-Babić
- Department of Anatomy, Histology and Embryology, University of Split School of Medicine, Šoltanska 2A, 21000 Split, Croatia
| | - Natalija Filipović
- Department of Anatomy, Histology and Embryology, University of Split School of Medicine, Šoltanska 2A, 21000 Split, Croatia
| | - Yu Katsuyama
- Department of Anatomy, Shiga University of Medical Science, Otsu 520-2192, Japan
| | - Zenon Pogorelić
- Department of Pediatric Surgery, Split University Hospital, 21000 Split, Croatia
| | - Katarina Vukojević
- Department of Anatomy, Histology and Embryology, University of Split School of Medicine, Šoltanska 2A, 21000 Split, Croatia
- Center for Translational Research in Biomedicine, University of Split School of Medicine, Šoltanska 2A, 21000 Split, Croatia
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2
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Talaverón R, Morado-Díaz CJ, Herrera A, Gálvez V, Pastor AM, Matarredona ER. The Gap Junction Inhibitor Octanol Decreases Proliferation and Increases Glial Differentiation of Postnatal Neural Progenitor Cells. Int J Mol Sci 2024; 25:6288. [PMID: 38927995 PMCID: PMC11203596 DOI: 10.3390/ijms25126288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2024] [Revised: 05/30/2024] [Accepted: 06/04/2024] [Indexed: 06/28/2024] Open
Abstract
Neural precursor cells (NPCs) that persist in the postnatal/adult subventricular zone (SVZ) express connexins that form hemichannels and gap junctions. Gap junctional communication plays a role in NPC proliferation and differentiation during development, but its relevance on postnatal age remains to be elucidated. In this work we aimed to evaluate the effect of the blockade of gap junctional communication on proliferation and cell fate of NPCs obtained from the SVZ of postnatal rats. NPCs were isolated and expanded in culture as neurospheres. Electron microscopy revealed the existence of gap junctions among neurosphere cells. Treatment of cultures with octanol, a broad-spectrum gap junction blocker, or with Gap27, a specific blocker for gap junctions formed by connexin43, produced a significant decrease in bromodeoxyuridine incorporation. Octanol treatment also exerted a dose-dependent antiproliferative effect on glioblastoma cells. To analyze possible actions on NPC fate, cells were seeded in the absence of mitogens. Treatment with octanol led to an increase in the percentage of astrocytes and oligodendrocyte precursors, whereas the percentage of neurons remained unchanged. Gap27 treatment, in contrast, did not modify the differentiation pattern of SVZ NPCs. Our results indicate that general blockade of gap junctions with octanol induces significant effects on the behavior of postnatal SVZ NPCs, by reducing proliferation and promoting glial differentiation.
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Affiliation(s)
- Rocío Talaverón
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, 41012 Seville, Spain;
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain; (C.J.M.-D.); (A.M.P.)
| | - Camilo J. Morado-Díaz
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain; (C.J.M.-D.); (A.M.P.)
| | - Alejandro Herrera
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain; (C.J.M.-D.); (A.M.P.)
| | - Victoria Gálvez
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain; (C.J.M.-D.); (A.M.P.)
| | - Angel M. Pastor
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain; (C.J.M.-D.); (A.M.P.)
| | - Esperanza R. Matarredona
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain; (C.J.M.-D.); (A.M.P.)
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3
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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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4
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Genet N, Genet G, Chavkin NW, Paila U, Fang JS, Vasavada HH, Goldberg JS, Acharya BR, Bhatt NS, Baker K, McDonnell SP, Huba M, Sankaranarayanan D, Ma GZM, Eichmann A, Thomas JL, Ffrench-Constant C, Hirschi KK. Connexin 43-mediated neurovascular interactions regulate neurogenesis in the adult brain subventricular zone. Cell Rep 2023; 42:112371. [PMID: 37043357 PMCID: PMC10564973 DOI: 10.1016/j.celrep.2023.112371] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 02/20/2023] [Accepted: 03/22/2023] [Indexed: 04/13/2023] Open
Abstract
The subventricular zone (SVZ) is the largest neural stem cell (NSC) niche in the adult brain; herein, the blood-brain barrier is leaky, allowing direct interactions between NSCs and endothelial cells (ECs). Mechanisms by which direct NSC-EC interactions in the adult SVZ control NSC behavior are unclear. We found that Cx43 is highly expressed by SVZ NSCs and ECs, and its deletion in either leads to increased NSC proliferation and neuroblast generation, suggesting that Cx43-mediated NSC-EC interactions maintain NSC quiescence. This is further supported by single-cell RNA sequencing and in vitro studies showing that ECs control NSC proliferation by regulating expression of genes associated with NSC quiescence and/or activation in a Cx43-dependent manner. Cx43 mediates these effects in a channel-independent manner involving its cytoplasmic tail and ERK activation. Such insights inform adult NSC regulation and maintenance aimed at stem cell therapies for neurodegenerative disorders.
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Affiliation(s)
- Nafiisha Genet
- Department of Cell Biology, Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; Departments of Medicine and Genetics, Yale University School of Medicine, New Haven, CT 06511, USA; Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT 06511, USA.
| | - Gael Genet
- Department of Cell Biology, Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Nicholas W Chavkin
- Department of Cell Biology, Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Umadevi Paila
- Department of Cell Biology, Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Jennifer S Fang
- Departments of Medicine and Genetics, Yale University School of Medicine, New Haven, CT 06511, USA; Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Hema H Vasavada
- Department of Cell Biology, Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; Departments of Medicine and Genetics, Yale University School of Medicine, New Haven, CT 06511, USA; Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Joshua S Goldberg
- Departments of Medicine and Genetics, Yale University School of Medicine, New Haven, CT 06511, USA; Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Bipul R Acharya
- Department of Cell Biology, Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Neha S Bhatt
- Departments of Medicine and Genetics, Yale University School of Medicine, New Haven, CT 06511, USA; Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Kasey Baker
- Departments of Medicine and Genetics, Yale University School of Medicine, New Haven, CT 06511, USA; Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06511, USA; Departments of Neuroscience and Cell Biology, Yale University School of Medicine, New Haven, CT 06511, USA; Department of Neurology, Yale University School of Medicine, New Haven, CT 06511, USA; Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Stephanie P McDonnell
- Department of Cell Biology, Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Mahalia Huba
- Department of Cell Biology, Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Danya Sankaranarayanan
- Department of Cell Biology, Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Gerry Z M Ma
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, UK; Faculty of Medicine and Health Sciences, University of East Anglia, Norwich, UK
| | - Anne Eichmann
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06511, USA; Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Jean-Leon Thomas
- Departments of Neuroscience and Cell Biology, Yale University School of Medicine, New Haven, CT 06511, USA; Department of Neurology, Yale University School of Medicine, New Haven, CT 06511, USA; Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Charles Ffrench-Constant
- MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, UK; Faculty of Medicine and Health Sciences, University of East Anglia, Norwich, UK
| | - Karen K Hirschi
- Department of Cell Biology, Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA; Departments of Medicine and Genetics, Yale University School of Medicine, New Haven, CT 06511, USA; Yale Cardiovascular Research Center, Yale University School of Medicine, New Haven, CT 06511, USA.
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5
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Talukdar S, Emdad L, Das SK, Fisher PB. GAP junctions: multifaceted regulators of neuronal differentiation. Tissue Barriers 2021; 10:1982349. [PMID: 34651545 DOI: 10.1080/21688370.2021.1982349] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Gap junctions are intercellular membrane channels consisting of connexin proteins, which contribute to direct cytoplasmic exchange of small molecules, substrates and metabolites between adjacent cells. These channels play important roles in neuronal differentiation, maintenance, survival and function. Gap junctions regulate differentiation of neurons from embryonic, neural and induced pluripotent stem cells. In addition, they control transdifferentiation of neurons from mesenchymal stem cells. The expression and levels of several connexins correlate with cell cycle changes and different stages of neurogenesis. Connexins such as Cx36, Cx45, and Cx26, play a crucial role in neuronal function. Several connexin knockout mice display lethal or severely impaired phenotypes. Aberrations in connexin expression is frequently associated with various neurodegenerative disorders. Gap junctions also act as promising therapeutic targets for neuronal regenerative medicine, because of their role in neural stem cell integration, injury and remyelination.
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Affiliation(s)
- Sarmistha Talukdar
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States.,Vcu Institute of Molecular Medicine, Richmond, VA, United States
| | - Luni Emdad
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States.,Vcu Institute of Molecular Medicine, Richmond, VA, United States.,Vcu Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States
| | - Swadesh K Das
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States.,Vcu Institute of Molecular Medicine, Richmond, VA, United States.,Vcu Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States
| | - Paul B Fisher
- Department of Human and Molecular Genetics, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States.,Vcu Institute of Molecular Medicine, Richmond, VA, United States.,Vcu Massey Cancer Center, Virginia Commonwealth University, School of Medicine, Richmond, VA, United States
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6
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Cho HJ, Velichkovska M, Schurhoff N, András IE, Toborek M. Extracellular vesicles regulate gap junction-mediated intercellular communication and HIV-1 infection of human neural progenitor cells. Neurobiol Dis 2021; 155:105388. [PMID: 33962010 DOI: 10.1016/j.nbd.2021.105388] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 04/13/2021] [Accepted: 05/03/2021] [Indexed: 12/11/2022] Open
Abstract
Human immunodeficiency virus-1 (HIV-1) has been shown to cross the blood-brain barrier and cause HIV-associated neurocognitive disorders (HAND) through a process that may involve direct or indirect interactions with the central nervous system (CNS) cells and alterations of amyloid β (Aβ) homeostasis. The present study focused on the mechanisms of HIV-1 infecting human neural progenitor cells (hNPCs) and affecting NPC intercellular communications with human brain endothelial cells (HBMEC). Despite the lack of the CD4 receptor, hNPCs were effectively infected by HIV-1 via a mechanism involving the chemokine receptors, CXCR4 and CCR5. HIV-1 infection increased expression of connexin-43 (Cx43), phosphorylated Cx43 (pCx43), and pannexin 2 (Panx2) protein levels in hNPCs, suggesting alterations in gap-junction (GJ) and pannexin channel communication. Indeed, a functional GJ assay indicated an increase in communication between HIV-infected hNPCs and non-infected HBMEC. We next analyzed the impact of HBMEC-derived extracellular vesicles (EVs) and EVs carrying Aβ (EV-Aβ) on the expression of Cx43, pCx43, and Panx2 in HIV-1 infected and non-infected hNPCs. Exposure to EV-Aβ resulted in significant reduction of Cx43 and pCx43 protein expression in non-infected hNPCs when compared to EV controls. Interestingly, EV-Aβ treatment significantly increased levels of Cx43, pCx43, and Panx2 in HIV-1-infected hNPCs when compared to non-infected controls. These results were confirmed in a GJ functional assay and an ATP release assay, which is an indicator of connexin hemichannel and/or pannexin channel functions. Overall, the current study demonstrates the importance of hNPCs in HIV-1 infection and indicates that intercellular communications between infected hNPCs and HBMEC can be effectively modulated by EVs carrying Aβ as their cargo.
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Affiliation(s)
- Hyung Joon Cho
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.
| | - Martina Velichkovska
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Nicolette Schurhoff
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Ibolya E András
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA
| | - Michal Toborek
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.
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7
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Purinergic Receptor Blockade with Suramin Increases Survival of Postnatal Neural Progenitor Cells In Vitro. Int J Mol Sci 2021; 22:ijms22020713. [PMID: 33445804 PMCID: PMC7828253 DOI: 10.3390/ijms22020713] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/07/2021] [Accepted: 01/08/2021] [Indexed: 01/04/2023] Open
Abstract
Neural progenitor cells (NPCs) are self-renewing and multipotent cells that persist in the postnatal and adult brain in the subventricular zone and the hippocampus. NPCs can be expanded in vitro to be used in cell therapy. However, expansion is limited, since the survival and proliferation of adult NPCs decrease with serial passages. Many signaling pathways control NPC survival and renewal. Among these, purinergic receptor activation exerts differential effects on the biology of adult NPCs depending on the cellular context. In this study, we sought to analyze the effect of a general blockade of purinergic receptors with suramin on the proliferation and survival of NPCs isolated from the subventricular zone of postnatal rats, which are cultured as neurospheres. Treatment of neurospheres with suramin induced a significant increase in neurosphere diameter and in NPC number attributed to a decrease in apoptosis. Proliferation and multipotency were not affected. Suramin also induced an increase in the gap junction protein connexin43 and in vascular endothelial growth factor, which might be involved in the anti-apoptotic effect. Our results offer a valuable tool for increasing NPC survival before implantation in the lesioned brain and open the possibility of using this drug as adjunctive therapy to NPC transplantation.
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8
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Mesnil M, Defamie N, Naus C, Sarrouilhe D. Brain Disorders and Chemical Pollutants: A Gap Junction Link? Biomolecules 2020; 11:51. [PMID: 33396565 PMCID: PMC7824109 DOI: 10.3390/biom11010051] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/22/2020] [Accepted: 12/23/2020] [Indexed: 02/07/2023] Open
Abstract
The incidence of brain pathologies has increased during last decades. Better diagnosis (autism spectrum disorders) and longer life expectancy (Parkinson's disease, Alzheimer's disease) partly explain this increase, while emerging data suggest pollutant exposures as a possible but still underestimated cause of major brain disorders. Taking into account that the brain parenchyma is rich in gap junctions and that most pollutants inhibit their function; brain disorders might be the consequence of gap-junctional alterations due to long-term exposures to pollutants. In this article, this hypothesis is addressed through three complementary aspects: (1) the gap-junctional organization and connexin expression in brain parenchyma and their function; (2) the effect of major pollutants (pesticides, bisphenol A, phthalates, heavy metals, airborne particles, etc.) on gap-junctional and connexin functions; (3) a description of the major brain disorders categorized as neurodevelopmental (autism spectrum disorders, attention deficit hyperactivity disorders, epilepsy), neurobehavioral (migraines, major depressive disorders), neurodegenerative (Parkinson's and Alzheimer's diseases) and cancers (glioma), in which both connexin dysfunction and pollutant involvement have been described. Based on these different aspects, the possible involvement of pollutant-inhibited gap junctions in brain disorders is discussed for prenatal and postnatal exposures.
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Affiliation(s)
- Marc Mesnil
- Laboratoire STIM, ERL7003 CNRS-Université de Poitiers, 1 rue G. Bonnet–TSA 51 106, 86073 Poitiers, France; (M.M.); (N.D.)
| | - Norah Defamie
- Laboratoire STIM, ERL7003 CNRS-Université de Poitiers, 1 rue G. Bonnet–TSA 51 106, 86073 Poitiers, France; (M.M.); (N.D.)
| | - Christian Naus
- Faculty of Medicine, Department of Cellular & Physiological Sciences, Life Sciences Institute, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T1Z3, Canada;
| | - Denis Sarrouilhe
- Laboratoire de Physiologie Humaine, Faculté de Médecine et Pharmacie, 6 rue de La Milétrie, bât D1, TSA 51115, 86073 Poitiers, France
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Talaverón R, Matarredona ER, Herrera A, Medina JM, Tabernero A. Connexin43 Region 266-283, via Src Inhibition, Reduces Neural Progenitor Cell Proliferation Promoted by EGF and FGF-2 and Increases Astrocytic Differentiation. Int J Mol Sci 2020; 21:ijms21228852. [PMID: 33238452 PMCID: PMC7700635 DOI: 10.3390/ijms21228852] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 11/20/2020] [Accepted: 11/20/2020] [Indexed: 12/13/2022] Open
Abstract
Neural progenitor cells (NPCs) are self-renewing cells that give rise to the major cells in the nervous system and are considered to be the possible cell of origin of glioblastoma. The gap junction protein connexin43 (Cx43) is expressed by NPCs, exerting channel-dependent and -independent roles. We focused on one property of Cx43—its ability to inhibit Src, a key protein in brain development and oncogenesis. Because Src inhibition is carried out by the sequence 266–283 of the intracellular C terminus in Cx43, we used a cell-penetrating peptide containing this sequence, TAT-Cx43266–283, to explore its effects on postnatal subventricular zone NPCs. Our results show that TAT-Cx43266–283 inhibited Src activity and reduced NPC proliferation and survival promoted by epidermal growth factor (EGF) and fibroblast growth factor-2 (FGF-2). In differentiation conditions, TAT-Cx43266–283 increased astrocyte differentiation at the expense of neuronal differentiation, which coincided with a reduction in Src activity and β-catenin expression. We propose that Cx43, through the region 266–283, reduces Src activity, leading to disruption of EGF and FGF-2 signaling and to down-regulation of β-catenin with effects on proliferation and differentiation. Our data indicate that the inhibition of Src might contribute to the complex role of Cx43 in NPCs and open new opportunities for further research in gliomagenesis.
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Affiliation(s)
- Rocío Talaverón
- Instituto de Neurociencias de Castilla y León (INCYL), Universidad de Salamanca, 37007 Salamanca, Spain; (R.T.); (J.M.M.)
| | | | - Alejandro Herrera
- Departamento de Fisiología, Universidad de Sevilla, 41012 Sevilla, Spain; (E.R.M.); (A.H.)
| | - José M. Medina
- Instituto de Neurociencias de Castilla y León (INCYL), Universidad de Salamanca, 37007 Salamanca, Spain; (R.T.); (J.M.M.)
| | - Arantxa Tabernero
- Instituto de Neurociencias de Castilla y León (INCYL), Universidad de Salamanca, 37007 Salamanca, Spain; (R.T.); (J.M.M.)
- Correspondence: ; Tel.: +34-923-29-45-00 (ext. 5311)
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10
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Dilger N, Neehus AL, Grieger K, Hoffmann A, Menssen M, Ngezahayo A. Gap Junction Dependent Cell Communication Is Modulated During Transdifferentiation of Mesenchymal Stem/Stromal Cells Towards Neuron-Like Cells. Front Cell Dev Biol 2020; 8:869. [PMID: 32984345 PMCID: PMC7487424 DOI: 10.3389/fcell.2020.00869] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 08/11/2020] [Indexed: 12/22/2022] Open
Abstract
In vitro transdifferentiation of patient-derived mesenchymal stem/stromal cells (MSCs) into neurons is of special interest for treatment of neurodegenerative diseases. Although there are encouraging studies, little is known about physiological modulations during this transdifferentiation process. Here, we focus on the analysis of gap junction dependent cell-cell communication and the expression pattern of gap junction-building connexins during small molecule-induced neuronal transdifferentiation of human bone marrow-derived MSCs. During this process, the MSC markers CD73, CD90, CD105, and CD166 were downregulated while the neuronal marker Tuj1 was upregulated. Moreover, the differentiation protocol used in the present study changed the cellular morphology and physiology. The MSCs evolved from a fibroblastoid morphology towards a neuronal shape with round cell bodies and neurite-like processes. Moreover, depolarization evoked action potentials in the transdifferentiated cells. MSCs expressed mRNAs encoding Cx43 and Cx45 as well as trace levels of Cx26, Cx37- and Cx40 and allowed transfer of microinjected Lucifer yellow. The differentiation protocol increased levels of Cx26 (mRNA and protein) and decreased Cx43 (mRNA and protein) while reducing the dye transfer. Cx36 mRNA was nearly undetectable in all cells regardless of treatment. Treatment of the cells with the gap junction coupling inhibitor carbenoxolone (CBX) only modestly altered connexin mRNA levels and had little effect on neuronal differentiation. Our study indicates that the small molecule-based differentiation protocol generates immature neuron-like cells from MSCs. This might be potentially interesting for elucidating physiological modifications and mechanisms in MSCs during the initial steps of differentiation towards a neuronal lineage.
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Affiliation(s)
- Nadine Dilger
- Department of Cell Physiology and Biophysics, Institute of Cell Biology and Biophysics, Leibniz University Hannover, Hanover, Germany
| | - Anna-Lena Neehus
- Department of Cell Physiology and Biophysics, Institute of Cell Biology and Biophysics, Leibniz University Hannover, Hanover, Germany.,Institute of Experimental Hematology, REBIRTH Research Center for Translational and Regenerative Medicine, Hannover Medical School (MHH), Hanover, Germany
| | - Klaudia Grieger
- Department of Cell Physiology and Biophysics, Institute of Cell Biology and Biophysics, Leibniz University Hannover, Hanover, Germany
| | - Andrea Hoffmann
- Graded Implants and Regenerative Strategies, Department of Orthopedic Surgery, Hannover Medical School, Hanover, Germany.,Lower Saxony Centre for Biomedical Engineering, Implant Research and Development (NIFE), Hanover, Germany
| | - Max Menssen
- Department of Biostatistics, Institute of Cell Biology and Biophysics, Leibniz University Hannover, Hanover, Germany
| | - Anaclet Ngezahayo
- Department of Cell Physiology and Biophysics, Institute of Cell Biology and Biophysics, Leibniz University Hannover, Hanover, Germany.,Center for Systems Neuroscience, University of Veterinary Medicine Hannover, Hanover, Germany
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11
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Kocovic DM, Limaye PV, Colburn LCH, Singh MB, Milosevic MM, Tadic J, Petronijevic M, Vrzic-Petronijevic S, Andjus PR, Antic SD. Cadmium versus Lanthanum Effects on Spontaneous Electrical Activity and Expression of Connexin Isoforms Cx26, Cx36, and Cx45 in the Human Fetal Cortex. Cereb Cortex 2020; 30:1244-1259. [PMID: 31408166 PMCID: PMC7132928 DOI: 10.1093/cercor/bhz163] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 06/25/2019] [Accepted: 06/25/2019] [Indexed: 12/29/2022] Open
Abstract
Electrical activity is important for brain development. In brain slices, human subplate neurons exhibit spontaneous electrical activity that is highly sensitive to lanthanum. Based on the results of pharmacological experiments in human fetal tissue, we hypothesized that hemichannel-forming connexin (Cx) isoforms 26, 36, and 45 would be expressed on neurons in the subplate (SP) zone. RNA sequencing of dissected human cortical mantles at ages of 17-23 gestational weeks revealed that Cx45 has the highest expression, followed by Cx36 and Cx26. The levels of Cx and pannexin expression between male and female fetal cortices were not significantly different. Immunohistochemical analysis detected Cx45- and Cx26-expressing neurons in the upper segment of the SP zone. Cx45 was present on the cell bodies of human SP neurons, while Cx26 was found on both cell bodies and dendrites. Cx45, Cx36, and Cx26 were strongly expressed in the cortical plate, where newborn migrating neurons line up to form cortical layers. New information about the expression of 3 "neuronal" Cx isoforms in each cortical layer/zone (e.g., SP, cortical plate) and pharmacological data with cadmium and lanthanum may improve our understanding of the cellular mechanisms underlying neuronal development in human fetuses and potential vulnerabilities.
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Affiliation(s)
- Dusica M Kocovic
- Faculty of Biology, University of Belgrade, Belgrade 11000, Serbia
| | - Pallavi V Limaye
- Institute for Systems Genomics, Stem Cell Institute, Department of Neuroscience, UConn Health, Farmington, CT 06030, USA
| | - Lauren C H Colburn
- Institute for Systems Genomics, Stem Cell Institute, Department of Neuroscience, UConn Health, Farmington, CT 06030, USA
| | - Mandakini B Singh
- Institute for Systems Genomics, Stem Cell Institute, Department of Neuroscience, UConn Health, Farmington, CT 06030, USA
| | - Milena M Milosevic
- Faculty of Biology, University of Belgrade, Belgrade 11000, Serbia
- Institute for Systems Genomics, Stem Cell Institute, Department of Neuroscience, UConn Health, Farmington, CT 06030, USA
| | - Jasmina Tadic
- Faculty of Medicine, University of Belgrade, Belgrade 11000, Serbia
| | | | | | - Pavle R Andjus
- Faculty of Biology, University of Belgrade, Belgrade 11000, Serbia
| | - Srdjan D Antic
- Institute for Systems Genomics, Stem Cell Institute, Department of Neuroscience, UConn Health, Farmington, CT 06030, USA
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12
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Connexin Signaling Is Involved in the Reactivation of a Latent Stem Cell Niche after Spinal Cord Injury. J Neurosci 2020; 40:2246-2258. [PMID: 32001613 DOI: 10.1523/jneurosci.2056-19.2020] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 01/20/2020] [Accepted: 01/23/2020] [Indexed: 12/26/2022] Open
Abstract
The ependyma of the adult spinal cord is a latent stem cell niche that is reactivated by spinal cord injury contributing new cells to the glial scar. The cellular events taking place in the early stages of the reaction of the ependyma to injury remain little understood. Ependymal cells are functionally heterogeneous with a mitotically active subpopulation lining the lateral domains of the central canal (CC) that are coupled via gap junctions. Gap junctions and connexin hemichannels are key regulators of the biology of neural progenitors during development and in adult neurogenic niches. Thus, we hypothesized that communication via connexins in the CC is developmentally regulated and may play a part in the reactivation of this latent stem cell niche after injury. To test these possibilities, we combined patch-clamp recordings of ependymal cells with immunohistochemistry for various connexins in the neonatal and the adult (P > 90) normal and injured spinal cord of male and female mice. We find that coupling among ependymal cells is downregulated as postnatal development proceeds but increases after injury, resembling the immature CC. The increase in gap junction coupling in the adult CC was paralleled by upregulation of connexin 26, which correlated with the resumption of proliferation and a reduction of connexin hemichannel activity. Connexin blockade reduced the injury-induced proliferation of ependymal cells. Our findings suggest that connexins are involved in the early reaction of ependymal cells to injury, representing a potential target to improve the contribution of the CC stem cell niche to repair.SIGNIFICANCE STATEMENT Ependymal cells in the adult spinal cord are latent progenitors that react to injury to support some degree of endogenous repair. Understanding the mechanisms by which these progenitor-like cells are regulated in the aftermath of spinal cord injury is critical to design future manipulations aimed at improving healing and functional recovery. Gap junctions and connexin hemichannels are key regulators of the biology of neural progenitors during development and in adult neurogenic niches. We find here that connexin signaling in the ependyma changes after injury of the adult spinal cord, functionally resembling the immature active-stem cell niche of neonatal animals. Our findings suggest that connexins in ependymal cells are potential targets to improve self-repair of the spinal cord.
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13
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Ma Y, Wang K, Pan J, Fan Z, Tian C, Deng X, Ma K, Xia X, Huang Y, Zheng JC. Induced neural progenitor cells abundantly secrete extracellular vesicles and promote the proliferation of neural progenitors via extracellular signal-regulated kinase pathways. Neurobiol Dis 2018; 124:322-334. [PMID: 30528256 DOI: 10.1016/j.nbd.2018.12.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 11/16/2018] [Accepted: 12/03/2018] [Indexed: 12/13/2022] Open
Abstract
Neural stem/progenitor cells (NPCs) are known to have potent therapeutic effects in neurological disorders through the secretion of extracellular vesicles (EVs). Despite the therapeutic potentials, the numbers of NPCs are limited in the brain, curbing the further use of EVs in the disease treatment. To overcome the limitation of NPC numbers, we used a three transcription factor (Brn2, Sox2, and Foxg1) somatic reprogramming approach to generate induced NPCs (iNPCs) from mouse fibroblasts and astrocytes. The resulting iNPCs released significantly higher numbers of EVs compared with wild-type NPCs (WT-NPCs). Furthermore, iNPCs-derived EVs (iNPC-EVs) promoted NPC function by increasing the proliferative potentials of WT-NPCs. Characterizations of EV contents through proteomics analysis revealed that iNPC-EVs contained higher levels of growth factor-associated proteins that were predicted to activate the down-stream extracellular signal-regulated kinase (ERK) pathways. As expected, the proliferative effects of iNPC-derived EVs on WT-NPCs can be blocked by an ERK pathway inhibitor. Our data suggest potent therapeutic effects of iNPC-derived EVs through the promotion of NPC proliferation, release of growth factors, and activation of ERK pathways. These studies will help develop highly efficient cell-free therapeutic strategies for the treatment of neurological diseases.
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Affiliation(s)
- Yizhao Ma
- Center for Translational Neurodegeneration and Regenerative Therapy, Shanghai Tenth People's Hospital affiliated to Tongji University School of Medicine, Shanghai 200072, China
| | - Kaizhe Wang
- Center for Translational Neurodegeneration and Regenerative Therapy, Shanghai Tenth People's Hospital affiliated to Tongji University School of Medicine, Shanghai 200072, China
| | - Jiabin Pan
- Center for Translational Neurodegeneration and Regenerative Therapy, Shanghai Tenth People's Hospital affiliated to Tongji University School of Medicine, Shanghai 200072, China
| | - Zhaohuan Fan
- Center for Translational Neurodegeneration and Regenerative Therapy, Shanghai Tenth People's Hospital affiliated to Tongji University School of Medicine, Shanghai 200072, China
| | - Changhai Tian
- Center for Translational Neurodegeneration and Regenerative Therapy, Shanghai Tenth People's Hospital affiliated to Tongji University School of Medicine, Shanghai 200072, China; Departments of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198-5930, USA
| | - Xiaobei Deng
- Center for Translational Neurodegeneration and Regenerative Therapy, Shanghai Tenth People's Hospital affiliated to Tongji University School of Medicine, Shanghai 200072, China
| | - Kangmu Ma
- Center for Translational Neurodegeneration and Regenerative Therapy, Shanghai Tenth People's Hospital affiliated to Tongji University School of Medicine, Shanghai 200072, China; Departments of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198-5930, USA
| | - Xiaohuan Xia
- Center for Translational Neurodegeneration and Regenerative Therapy, Shanghai Tenth People's Hospital affiliated to Tongji University School of Medicine, Shanghai 200072, China.
| | - Yunlong Huang
- Center for Translational Neurodegeneration and Regenerative Therapy, Shanghai Tenth People's Hospital affiliated to Tongji University School of Medicine, Shanghai 200072, China; Departments of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198-5930, USA.
| | - Jialin C Zheng
- Center for Translational Neurodegeneration and Regenerative Therapy, Shanghai Tenth People's Hospital affiliated to Tongji University School of Medicine, Shanghai 200072, China; Collaborative Innovation Center for Brain Science, Tongji University, Shanghai 200092, China; Departments of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198-5930, USA; Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198-5930, USA.
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14
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Abstract
Purpose of Review Considerable progress has been made in the field of stem cell research; nonetheless, the use of stem cells for regenerative medicine therapies, for either endogenous tissue repair or cellular grafts post injury, remains a challenge. To better understand how to maintain stem cell potential in vivo and promote differentiation ex vivo, it is fundamentally important to elucidate the interactions between stem cells and their surrounding partners within their distinct niches. Recent Findings Among the vast array of proteins depicted as mediators for cell-to-cell interactions, connexin-comprised gap junctions play pivotal roles in the regulation of stem cell fate both in vivo and in vitro. Summary This review summarizes and illustrates the current knowledge regarding the multifaceted roles of Cx43, specifically, in various stem cell niches.
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Affiliation(s)
- Nafiisha Genet
- Department of Medicine, Genetics and Biomedical Engineering, Yale Cardiovascular Research Center, Vascular Biology Therapeutics Program, New Haven, USA.,2Yale Stem Cell Center Yale University School of Medicine, 300 George St, New Haven, CT 06511 USA
| | - Neha Bhatt
- Department of Medicine, Genetics and Biomedical Engineering, Yale Cardiovascular Research Center, Vascular Biology Therapeutics Program, New Haven, USA.,2Yale Stem Cell Center Yale University School of Medicine, 300 George St, New Haven, CT 06511 USA
| | - Antonin Bourdieu
- Department of Medicine, Genetics and Biomedical Engineering, Yale Cardiovascular Research Center, Vascular Biology Therapeutics Program, New Haven, USA.,2Yale Stem Cell Center Yale University School of Medicine, 300 George St, New Haven, CT 06511 USA
| | - Karen K Hirschi
- Department of Medicine, Genetics and Biomedical Engineering, Yale Cardiovascular Research Center, Vascular Biology Therapeutics Program, New Haven, USA.,2Yale Stem Cell Center Yale University School of Medicine, 300 George St, New Haven, CT 06511 USA
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15
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Greer K, Chen J, Brickler T, Gourdie R, Theus MH. Modulation of gap junction-associated Cx43 in neural stem/progenitor cells following traumatic brain injury. Brain Res Bull 2017; 134:38-46. [PMID: 28648814 PMCID: PMC5597487 DOI: 10.1016/j.brainresbull.2017.06.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 06/12/2017] [Accepted: 06/20/2017] [Indexed: 12/17/2022]
Abstract
Restoration of learning and memory deficits following traumatic brain injury (TBI) is attributed, in part, to enhanced neural stem/progenitor cell (NSPCs) function. Recent findings suggest gap junction (GJ)-associated connexin 43 (Cx43) plays a key role in the cell cycle regulation and function of NSPCs and is modulated following TBI. Here, we demonstrate that Cx43 is up-regulated in the dentate gyrus following TBI and is expressed on vimentin-positive cells in the subgranular zone. To test the role of Cx43 on NSPCs, we exposed primary cultures to the α-connexin Carboxyl Terminal (αCT1) peptide which selectively modulates GJ-associated Cx43. Treatment with αCT1 substantially reduced proliferation and increased caspase 3/7 expression on NSPCs in a dose-dependent manner. αCT1 exposure also reduced overall expression of Cx43 and phospho (p)-Serine368. These findings demonstrate that Cx43 positively regulates adult NPSCs; the modulation of which may influence changes in the dentate gyrus following TBI.
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Affiliation(s)
- Kisha Greer
- The Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, 215 Duck Pond Drive, Blacksburg, VA 24061, USA
| | - Jiang Chen
- The Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, 215 Duck Pond Drive, Blacksburg, VA 24061, USA
| | - Thomas Brickler
- The Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, 215 Duck Pond Drive, Blacksburg, VA 24061, USA
| | - Robert Gourdie
- Virgnia Tech Carillion Research Institute, College of Medicine, 2 Riverside Circle, Roanoke, VA 24016, USA
| | - Michelle H Theus
- The Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, 215 Duck Pond Drive, Blacksburg, VA 24061, USA.
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16
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Jiao Q, Li X, An J, Zhang Z, Chen X, Tan J, Zhang P, Lu H, Liu Y. Cell-Cell Connection Enhances Proliferation and Neuronal Differentiation of Rat Embryonic Neural Stem/Progenitor Cells. Front Cell Neurosci 2017; 11:200. [PMID: 28785204 PMCID: PMC5519523 DOI: 10.3389/fncel.2017.00200] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 06/26/2017] [Indexed: 01/22/2023] Open
Abstract
Cell-cell interaction as one of the niche signals plays an important role in the balance of stem cell quiescence and proliferation or differentiation. In order to address the effect and the possible mechanisms of cell-cell connection on neural stem/progenitor cells (NSCs/NPCs) proliferation and differentiation, upon passaging, NSCs/NPCs were either dissociated into single cell as usual (named Group I) or mechanically triturated into a mixture of single cell and small cell clusters containing direct cell-cell connections (named Group II). Then the biological behaviors including proliferation and differentiation of NSCs/NPCs were observed. Moreover, the expression of gap junction channel, neurotrophic factors and the phosphorylation status of MAPK signals were compared to investigate the possible mechanisms. Our results showed that, in comparison to the counterparts in Group I, NSCs/NPCs in Group II survived well with preferable neuronal differentiation. In coincidence with this, the expression of connexin 45 (Cx45), as well as brain derived neurotrophic factor (BDNF) and neurotrophin 3 (NT-3) in Group II were significantly higher than those in Group I. Phosphorylation of ERK1/2 and JNK2 were significantly upregulated in Group II too, while no change was found about p38. Furthermore, the differences of NSCs/NPCs biological behaviors between Group I and II completely disappeared when ERK and JNK phosphorylation were inhibited. These results indicated that cell-cell connection in Group II enhanced NSCs/NPCs survival, proliferation and neuronal differentiation through upregulating the expression of gap junction and neurotrophic factors. MAPK signals- ERK and JNK might contribute to the enhancement. Efforts for maintaining the direct cell-cell connection are worth making to provide more favorable niches for NSCs/NPCs survival, proliferation and neuronal differentiation.
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Affiliation(s)
- Qian Jiao
- Institute of Neurobiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science CenterXi'an, China.,Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education of China, Xi'an Jiaotong UniversityBeijing, China.,Department of Physiology, Medical College of Qingdao UniversityQingdao, China
| | - Xingxing Li
- Institute of Neurobiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science CenterXi'an, China.,Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education of China, Xi'an Jiaotong UniversityBeijing, China
| | - Jing An
- Institute of Neurobiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science CenterXi'an, China.,Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education of China, Xi'an Jiaotong UniversityBeijing, China
| | - Zhichao Zhang
- Institute of Neurobiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science CenterXi'an, China.,Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education of China, Xi'an Jiaotong UniversityBeijing, China
| | - Xinlin Chen
- Institute of Neurobiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science CenterXi'an, China.,Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education of China, Xi'an Jiaotong UniversityBeijing, China
| | - Jing Tan
- Institute of Neurobiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science CenterXi'an, China.,Department of Anesthesiology, The First Affiliated Hospital, Xi'an Jiaotong University Health Science CenterXi'an, China
| | - Pengbo Zhang
- Department of Anesthesiology, The Second Affiliated Hospital, Health Science Center, Xi'an Jiaotong UniversityXi'an, China
| | - Haixia Lu
- Institute of Neurobiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science CenterXi'an, China.,Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education of China, Xi'an Jiaotong UniversityBeijing, China
| | - Yong Liu
- Institute of Neurobiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science CenterXi'an, China.,Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education of China, Xi'an Jiaotong UniversityBeijing, China
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17
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Lapato AS, Tiwari-Woodruff SK. Connexins and pannexins: At the junction of neuro-glial homeostasis & disease. J Neurosci Res 2017; 96:31-44. [PMID: 28580666 DOI: 10.1002/jnr.24088] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 04/08/2017] [Accepted: 05/01/2017] [Indexed: 12/15/2022]
Abstract
In the central nervous system (CNS), connexin (Cx)s and pannexin (Panx)s are an integral component of homeostatic neuronal excitability and synaptic plasticity. Neuronal Cx gap junctions form electrical synapses across biochemically similar GABAergic networks, allowing rapid and extensive inhibition in response to principle neuron excitation. Glial Cx gap junctions link astrocytes and oligodendrocytes in the pan-glial network that is responsible for removing excitotoxic ions and metabolites. In addition, glial gap junctions help constrain excessive excitatory activity in neurons and facilitate astrocyte Ca2+ slow wave propagation. Panxs do not form gap junctions in vivo, but Panx hemichannels participate in autocrine and paracrine gliotransmission, alongside Cx hemichannels. ATP and other gliotransmitters released by Cx and Panx hemichannels maintain physiologic glutamatergic tone by strengthening synapses and mitigating aberrant high frequency bursting. Under pathological depolarizing and inflammatory conditions, gap junctions and hemichannels become dysregulated, resulting in excessive neuronal firing and seizure. In this review, we present known contributions of Cxs and Panxs to physiologic neuronal excitation and explore how the disruption of gap junctions and hemichannels lead to abnormal glutamatergic transmission, purinergic signaling, and seizures.
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Affiliation(s)
- Andrew S Lapato
- Division of Biomedical Sciences, School of Medicine, University of California Riverside, Riverside, CA, 92521.,Center for Glial-Neuronal Interactions, University of California Riverside, Riverside, CA, 92521
| | - Seema K Tiwari-Woodruff
- Division of Biomedical Sciences, School of Medicine, University of California Riverside, Riverside, CA, 92521.,Center for Glial-Neuronal Interactions, University of California Riverside, Riverside, CA, 92521.,Neuroscience Graduate Program, University of California Riverside, Riverside, CA, 92521
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18
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Bosch PJ, Fuller LC, Sleeth CM, Weiner JA. Akirin2 is essential for the formation of the cerebral cortex. Neural Dev 2016; 11:21. [PMID: 27871306 PMCID: PMC5117564 DOI: 10.1186/s13064-016-0076-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 11/10/2016] [Indexed: 12/22/2022] Open
Abstract
Background The proper spatial and temporal regulation of dorsal telencephalic progenitor behavior is a prerequisite for the formation of the highly-organized, six-layered cerebral cortex. Premature differentiation of cells, disruption of cell cycle timing, excessive apoptosis, and/or incorrect neuronal migration signals can have devastating effects, resulting in a number of neurodevelopmental disorders involving microcephaly and/or lissencephaly. Though genes encoding many key players in cortical development have been identified, our understanding remains incomplete. We show that the gene encoding Akirin2, a small nuclear protein, is expressed in the embryonic telencephalon. Converging evidence indicates that Akirin2 acts as a bridge between transcription factors (including Twist and NF-κB proteins) and the BAF (SWI/SNF) chromatin remodeling machinery to regulate patterns of gene expression. Constitutive knockout of Akirin2 is early embryonic lethal in mice, while restricted loss in B cells led to disrupted proliferation and cell survival. Methods We generated cortex-restricted Akirin2 knockouts by crossing mice harboring a floxed Akirin2 allele with the Emx1-Cre transgenic line and assessed the resulting embryos using in situ hybridization, EdU labeling, and immunohistochemistry. Results The vast majority of Akirin2 mutants do not survive past birth, and exhibit extreme microcephaly, with little dorsal telencephalic tissue and no recognizable cortex. This is primarily due to massive cell death of early cortical progenitors, which begins at embryonic day (E)10, shortly after Emx1-Cre is active. Immunostaining and cell cycle analysis using EdU labeling indicate that Akirin2-null progenitors fail to proliferate normally, produce fewer neurons, and undergo extensive apoptosis. All of the neurons that are generated in Akirin2 mutants also undergo apoptosis by E12. In situ hybridization for Wnt3a and Wnt-responsive genes suggest defective formation and/or function of the cortical hem in Akirin2 null mice. Furthermore, the apical ventricular surface becomes disrupted, and Sox2-positive progenitors are found to “spill” into the lateral ventricle. Conclusions Our data demonstrate a previously-unsuspected role for Akirin2 in early cortical development and, given its known nuclear roles, suggest that it may act to regulate gene expression patterns critical for early progenitor cell behavior and cortical neuron production. Electronic supplementary material The online version of this article (doi:10.1186/s13064-016-0076-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Peter J Bosch
- Department of Biology, The University of Iowa, Iowa City, IA, USA
| | - Leah C Fuller
- Department of Biology, The University of Iowa, Iowa City, IA, USA
| | - Carolyn M Sleeth
- Department of Biology, The University of Iowa, Iowa City, IA, USA
| | - Joshua A Weiner
- Department of Biology and Department of Psychiatry, The University of Iowa, 143 Biology Building, Iowa City, IA, 52242, USA.
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19
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Carson R, Monaghan-Nichols AP, DeFranco DB, Rudine AC. Effects of antenatal glucocorticoids on the developing brain. Steroids 2016; 114:25-32. [PMID: 27343976 PMCID: PMC5052110 DOI: 10.1016/j.steroids.2016.05.012] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 05/25/2016] [Accepted: 05/30/2016] [Indexed: 01/13/2023]
Abstract
Glucocorticoids (GCs) regulate distinct physiological processes in the developing fetus, in particular accelerating organ maturation that enables the fetus to survive outside the womb. In preterm birth, the developing fetus does not receive sufficient exposure to endogenous GCs in utero for proper organ development predisposing the neonate to complications including intraventricular hemorrhage, respiratory distress syndrome (RDS) and necrotizing enterocolitis (NEC). Synthetic GCs (sGCs) have proven useful in the prevention of these complications since they are able to promote the rapid maturation of underdeveloped organs present in the fetus. While these drugs have proven to be clinically effective in the prevention of IVH, RDS and NEC, they may also trigger adverse developmental side effects. This review will examine the current clinical use of antenatal sGC therapy in preterm birth, their placental metabolism, and their effects on the developing brain.
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Affiliation(s)
- Ross Carson
- University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - A Paula Monaghan-Nichols
- University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Department of Neurobiology, United States
| | - Donald B DeFranco
- University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Department of Pharmacology and Chemical Biology, United States
| | - Anthony C Rudine
- University of Pittsburgh School of Medicine, Pittsburgh, PA, United States; Department of Pediatrics, Division of Newborn Medicine, United States.
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20
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Nagy C, Torres-Platas SG, Mechawar N, Turecki G. Repression of Astrocytic Connexins in Cortical and Subcortical Brain Regions and Prefrontal Enrichment of H3K9me3 in Depression and Suicide. Int J Neuropsychopharmacol 2016; 20:50-57. [PMID: 27516431 PMCID: PMC5737582 DOI: 10.1093/ijnp/pyw071] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Major depressive disorder has been associated with dysfunctional astrocytic networks. The underlying causes, extent, and consequences of such dysfunctions remain to be characterized. Astrocyte-astrocyte communication occurs principally through gap junction channels primarily formed by connexin 30 and 43 (CX30 and CX43). We previously reported decreased connexin expression in the prefrontal cortex of depressed suicides. In the present study, we investigated whether these changes are mediated by epigenetic regulation, and expanded gene expression quantifications to other cortical and subcortical regions to assess the regional distribution of connexion disruptions in depressed suicides. METHODS The expression of CX30 and CX43 was measured by real-time PCR in samples of neocortex (Brodmann areas 4 and 17), cerebellar cortex, mediodorsal thalamus, and caudate nucleus of 22 depressed suicides and 22 matched sudden-death controls. Chromatin immunoprecipitation was used to measure enrichment levels of the repressive chromatin mark H3K9me3 in the prefrontal cortex. RESULTS We found a consistent downregulation of connexin genes in all regions examined, except in the cerebellum where an increase in the expression of CX30 was measured and using chromatin immunoprecipitation we observed an enrichment of H3K9me3 for both Cx30 and Cx43 in the prefrontal cortex. CONCLUSIONS Our study shows widespread astrocytic CX gene repression in depressed suicides that is mediated, at least in part, through epigenetic mechanisms. Taken together, these findings support the notion of widespread cerebral astrocytic dysfunction in major depressive disorder.
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Affiliation(s)
- Corina Nagy
- McGill Group for Suicide Studies, Douglas Mental Health University Institute (Ms Nagy, Drs Torres-Platas, Machawar, and Turecki); Departments of Neurology and Neurosurgery (Ms Nagy, Drs Torres-Platas, Machawar, and Turecki), Human Genetics (Dr Turecki), and Psychiatry (Drs Mechawar and Turecki), McGill University, Verdun, Québec, Canada
| | - Susana G. Torres-Platas
- McGill Group for Suicide Studies, Douglas Mental Health University Institute (Ms Nagy, Drs Torres-Platas, Machawar, and Turecki); Departments of Neurology and Neurosurgery (Ms Nagy, Drs Torres-Platas, Machawar, and Turecki), Human Genetics (Dr Turecki), and Psychiatry (Drs Mechawar and Turecki), McGill University, Verdun, Québec, Canada
| | - Naguib Mechawar
- McGill Group for Suicide Studies, Douglas Mental Health University Institute (Ms Nagy, Drs Torres-Platas, Machawar, and Turecki); Departments of Neurology and Neurosurgery (Ms Nagy, Drs Torres-Platas, Machawar, and Turecki), Human Genetics (Dr Turecki), and Psychiatry (Drs Mechawar and Turecki), McGill University, Verdun, Québec, Canada
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21
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Abstract
Establishment of cellular networks and calcium homeostasis are essential for embryonic stem cell proliferation and differentiation. We also hypothesized that adult neural progenitor cells form functional cellular networks relevant for their development. We isolated neuronal progenitor cells from the subventricular zone of 5-week-old mice to investigate the role of gap junctions, calcium homeostasis, and cellular networks in cell differentiation and survival. Western blotting and reverse transcription-PCR showed that the cells expressed the gap junction components connexin 26, 36, 43, and 45, and that expression of connexin 43 increased in early (8 days) differentiated cells. Transmission electron microscopy and immunocytochemistry also indicated that gap junctions were present. Scrape-loading experiments showed dye transfer between cells that could be prevented by gapjunction blockers; thus, functional intercellular gap junctions had been established. However, dye transfer was four times stronger in differentiated cultures, correlating with the increased connexin 43 expression. During time-lapse calcium imaging, both differentiated and undifferentiated cultures showed spontaneous calcium activity that was reduced by gap junction blockers. Cross-correlation analysis of the calcium recordings showed that the cells were interconnected through gap junctions and that the early-differentiated cells were organized in small-world networks. Gap junction blockers did not affect proliferation and differentiation, but resulted in twice as many apoptotic cells. mRNAi knockdown of connexin 43 also doubled the number of apoptotic cells. We conclude that adult neural progenitor cells form networks in vitro that are strengthened during early differentiation by increased expression of connexin 43. The networks are functional and improve cell survival.
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Bosone C, Andreu A, Echevarria D. GAP junctional communication in brain secondary organizers. Dev Growth Differ 2016; 58:446-55. [PMID: 27273333 DOI: 10.1111/dgd.12297] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 05/05/2016] [Accepted: 05/05/2016] [Indexed: 11/28/2022]
Abstract
Gap junctions (GJs) are integral membrane proteins that enable the direct cytoplasmic exchange of ions and low molecular weight metabolites between adjacent cells. They are formed by the apposition of two connexons belonging to adjacent cells. Each connexon is formed by six proteins, named connexins (Cxs). Current evidence suggests that gap junctions play an important part in ensuring normal embryo development. Mutations in connexin genes have been linked to a variety of human diseases, although the precise role and the cell biological mechanisms of their action remain almost unknown. Among the big family of Cxs, several are expressed in nervous tissue but just a few are expressed in the anterior neural tube of vertebrates. Many efforts have been made to elucidate the molecular bases of Cxs cell biology and how they influence the morphogenetic signal activity produced by brain signaling centers. These centers, orchestrated by transcription factors and morphogenes determine the axial patterning of the mammalian brain during its specification and regionalization. The present review revisits the findings of GJ composed by Cx43 and Cx36 in neural tube patterning and discuss Cx43 putative enrollment in the control of Fgf8 signal activity coming from the well known secondary organizer, the isthmic organizer.
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Affiliation(s)
- Camilla Bosone
- Instituto de Neurociencias, Universidad Miguel Hernández & Consejo Superior de Investigaciones Científicas, 03550, Sant Joan d'Alacant, Spain
| | - Abraham Andreu
- Institut de Biologie Paris-Seine (IBPS), Developmental Biology Laboratory, University Pierre and Marie Curie, Paris, France
| | - Diego Echevarria
- Instituto de Neurociencias, Universidad Miguel Hernández & Consejo Superior de Investigaciones Científicas, 03550, Sant Joan d'Alacant, Spain
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Abstract
Connexins and pannexins share very similar structures and functions; they also exhibit overlapping expression in many stages of neuronal development. Here, we review evidence implicating connexin- and pannexin-mediated communication in the regulation of the birth and development of neurons, specifically Cx26, Cx30, Cx32, Cx36, Cx43, Cx45, Panx1, and Panx2. We begin by dissecting the involvement of these proteins in the generation and development of new neurons in the embryonic, postnatal, and adult brain. Next we briefly outline common mechanisms employed by both pannexins and connexins in these roles, including modulation of purinergic receptor signalling and signalling nexus functions. Throughout this review we highlight developing themes as well as important gaps in knowledge to be bridged.
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Affiliation(s)
- Leigh Anne Swayne
- />Division of Medical Sciences, University of Victoria, Medical Sciences Building Rm 224, 3800 Finnerty Rd, Victoria, BC V8P5C2 Canada
| | - Steffany A. L. Bennett
- />Department of Biochemistry, Microbiology and Immunology, Neural Regeneration Laboratory, Ottawa Institute of Systems Biology, University of Ottawa, Ottawa, ON Canada
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Watters AK, Rom S, Hill JD, Dematatis MK, Zhou Y, Merkel SF, Andrews AM, Cena J, Potula R, Skuba A, Son YJ, Persidsky Y, Ramirez SH. Identification and dynamic regulation of tight junction protein expression in human neural stem cells. Stem Cells Dev 2016; 24:1377-89. [PMID: 25892136 DOI: 10.1089/scd.2014.0497] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Recent reports indicate that neural stem cells (NSCs) exist in a cluster-like formation in close proximity to cerebral microvessels. Similar appearing clusters can be seen ex vivo in NSC cultures termed neurospheres. It is known that this neurosphere configuration is important for preserving stemness and a proliferative state. How NSCs form neurospheres or neuroclusters remains largely undetermined. In this study, we show that primary human NSCs express the tight junction proteins (TJPs): zonula occludens-1 (ZO-1), occludin, claudin-1, -3, -5, and -12. The relative mRNA expression was measured by quantitative polymerase chain reaction, and protein expression was confirmed by flow cytometry and immunofluorescence microscopy. Our results show that downregulation of TJPs occurs as neuronal differentiation is induced, suggesting that control of TJPs may be tied to the neuronal differentiation program. Importantly, upon specific knockdown of the accessory TJP, ZO-1, undifferentiated NSCs showed decreased levels of key stem cell markers. Taken together, our results indicate that TJPs possibly aid in maintaining the intercellular configuration of NSCs and that reduction in TJP expression consequently affects the stemness status.
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Affiliation(s)
- Andrea K Watters
- 1Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Slava Rom
- 1Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Jeremy D Hill
- 1Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Marie K Dematatis
- 1Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Yu Zhou
- 1Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Steven F Merkel
- 1Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Allison M Andrews
- 1Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Jonathan Cena
- 1Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Raghava Potula
- 1Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania.,2Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Andrew Skuba
- 3Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Young-Jin Son
- 3Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Yuri Persidsky
- 1Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania.,2Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia, Pennsylvania
| | - Servio H Ramirez
- 1Department of Pathology and Laboratory Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania.,2Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia, Pennsylvania.,3Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania
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Talaverón R, Fernández P, Escamilla R, Pastor AM, Matarredona ER, Sáez JC. Neural progenitor cells isolated from the subventricular zone present hemichannel activity and form functional gap junctions with glial cells. Front Cell Neurosci 2015; 9:411. [PMID: 26528139 PMCID: PMC4602088 DOI: 10.3389/fncel.2015.00411] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Accepted: 09/25/2015] [Indexed: 01/19/2023] Open
Abstract
The postnatal subventricular zone (SVZ) lining the walls of the lateral ventricles contains neural progenitor cells (NPCs) that generate new olfactory bulb interneurons. Communication via gap junctions between cells in the SVZ is involved in NPC proliferation and in neuroblast migration towards the olfactory bulb. SVZ NPCs can be expanded in vitro in the form of neurospheres that can be used for transplantation purposes after brain injury. We have previously reported that neurosphere-derived NPCs form heterocellular gap junctions with host glial cells when they are implanted after mechanical injury. To analyze functionality of NPC-glial cell gap junctions we performed dye coupling experiments in co-cultures of SVZ NPCs with astrocytes or microglia. Neurosphere-derived cells expressed mRNA for at least the hemichannel/gap junction channel proteins connexin 26 (Cx26), Cx43, Cx45 and pannexin 1 (Panx1). Dye coupling experiments revealed that gap junctional communication occurred among neurosphere cells (incidence of coupling: 100%). Moreover, hemichannel activity was also detected in neurosphere cells as evaluated in time-lapse measurements of ethidium bromide uptake. Heterocellular coupling between NPCs and glial cells was evidenced in co-cultures of neurospheres with astrocytes (incidence of coupling: 91.0 ± 4.7%) or with microglia (incidence of coupling: 71.9 ± 6.7%). Dye coupling in neurospheres and in co-cultures was inhibited by octanol, a gap junction blocker. Altogether, these results suggest the existence of functional hemichannels and gap junction channels in postnatal SVZ neurospheres. In addition, they demonstrate that SVZ-derived NPCs can establish functional gap junctions with astrocytes or microglia. Therefore, cell-cell communication via gap junctions and hemichannels with host glial cells might subserve a role in the functional integration of NPCs after implantation in the damaged brain.
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Affiliation(s)
- Rocío Talaverón
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla Sevilla, Spain
| | - Paola Fernández
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago de Chile, Chile and Instituto Milenio, Centro Interdisciplinario de Neurociencias de Valparaíso Chile
| | - Rosalba Escamilla
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago de Chile, Chile and Instituto Milenio, Centro Interdisciplinario de Neurociencias de Valparaíso Chile
| | - Angel M Pastor
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla Sevilla, Spain
| | | | - Juan C Sáez
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago de Chile, Chile and Instituto Milenio, Centro Interdisciplinario de Neurociencias de Valparaíso Chile
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Vitale ML, Barry A. Biphasic Effect of Basic Fibroblast Growth Factor on Anterior Pituitary Folliculostellate TtT/GF Cell Coupling, and Connexin 43 Expression and Phosphorylation. J Neuroendocrinol 2015; 27:787-801. [PMID: 26265106 DOI: 10.1111/jne.12308] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 07/08/2015] [Accepted: 08/07/2015] [Indexed: 01/01/2023]
Abstract
Basic fibroblast growth factor (bFGF) is a mitogenic and differentiating cytokine. In the anterior pituitary, folliculostellate (FS) cells constitute the major source of bFGF. bFGF affects endocrine cell proliferation and secretion in the anterior pituitary. In addition, bFGF increases its own expression by acting directly on FS cells. FS cell Cx43-mediated gap junction intercellular communication allows the establishment of an intrapituitary network for the transmission of information. In the present study, we assessed how bFGF regulates FS cell coupling. Time course studies were carried out on the FS cell line TtT/GF. Short-term bFGF treatment induced a transient cell uncoupling and the phosphorylation in Ser368 of membrane-bound Cx43 without modifying Cx43 levels. We demonstrated the involvement of the protein kinase C (PKC) isoform α in the phosphorylation of Cx43 in S368. Moreover, we showed that bFGF induced PKCα activation by stimulating its expression, phosphorylation and association with the plasma membrane. The long-term incubation with bFGF increased TtT/GF cell coupling, total Cx43 levels and Cx43 accumulation at the cell membrane of cytoplasmic projections. The Cx43 level increase was a result of the stimulation of Cx43 gene transcription as mediated by the extracellular-regulated kinase 1/2 signalling pathway. Taken together, the data show that bFGF modulates TtT/GF cell coupling by activating different pathways that lead to opposite effects on Cx43 phosphorylation and expression depending on the duration of the exposure of the cells to bFGF. A short-term bFGF exposure reduces cell-to-cell communication as a mean of desynchronising FS cells. By contrast, long-term exposure to bFGF enhances cell-to-cell communication and facilitates coordination among FS cells.
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Affiliation(s)
- M L Vitale
- Département de Pathologie et Biologie Cellulaire, Faculté de Médecine, Université de Montréal, Montreal, Québec, Canada
| | - A Barry
- Département de Pathologie et Biologie Cellulaire, Faculté de Médecine, Université de Montréal, Montreal, Québec, Canada
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Kim KT, Kim HJ, Cho DC, Bae JS, Park SW. Substance P stimulates proliferation of spinal neural stem cells in spinal cord injury via the mitogen-activated protein kinase signaling pathway. Spine J 2015; 15:2055-65. [PMID: 25921821 DOI: 10.1016/j.spinee.2015.04.032] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 03/20/2015] [Accepted: 04/20/2015] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Substance P (SP) is a neuropeptide that can influence neural stem/progenitor cell (NSPC) proliferation and neurogenesis in the brain. However, we could not find any experimental study that investigates SP action in the spinal cord. PURPOSE The aims of our study were to investigate the potential of the neuropeptide SP in promoting the proliferation of spinal cord-derived NSPCs (SC-NSPCs) after spinal cord injury (SCI) and to clarify the roles of the mitogen-activated protein (MAP) kinase signaling pathway in the process. STUDY DESIGN This is a randomized animal study. METHODS The SC-NSPCs were suspended in 100 μL of a neurobasal medium containing SP (binds neurokinin-1 receptor [NK1R]) or L-703,606 (NK1R antagonist) and cultured in a 96-well plate for 5 days. A cell proliferation assay was performed using a 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay. A cord clipping method was used for the SCI model. Substance P and the NK1R antagonist (L-703,606) were infused intrathecally in SCI and sham models. Neural stem/progenitor cell proliferation was evaluated with immunostaining for bromodeoxyuridine (BrdU) and the immature neural marker nestin. An immunoblotting method was used for evaluating the MAP kinase signaling protein that contains extracellular signal-regulated kinases (ERKs and p38) and β-actin as the control group. RESULTS In vitro, SP (0.01-10 μmol/L) increased the proliferation of cultured SC-NSPCs, with a peak increase of 35±2% at the 0.1 μmol/L concentration. Substance P of 0.1 μmol/L continuously increased SC-NSPC proliferation from 6 hours to 5 days, whereas the proliferation decreased from 18% to 98% with L-703,606 (1-10 μM). Intrathecal infusion of SP (1 μmol/L) for 7 days significantly increased the number of proliferating NPSCs (cells positive for both BrdU and nestin) in the spinal cord (by 120±17%, p<.05) in adult rats, but infusion of L-703,606 (10 μmol/L) significantly decreased the post-SCI induction of NPSC proliferation in the spinal cord (by 87±4%). Also, SP stimulates proliferation of SC-NSPCs via the MAP kinase signaling pathway, especially the phosphorylated ERK and phosphorylated p38 proteins. The phosphorylated ERK and phosphorylated p38 protein levels increased with SP (0.1 μmol/L, p<.05). CONCLUSIONS These data indicate that SP can promote proliferation of SC-NSPCs in SCI and normal conditions and have important roles in neuronal regeneration after SCI. Also, ERKs and p38 MAP kinases are important signaling proteins in this process.
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Affiliation(s)
- Kyoung-Tae Kim
- Department of Neurosurgery, Kyungpook National University Hospital, 50 Samduk-2-ga, Jung-gu, Daegu 700-721, Republic of Korea.
| | - Hye-Jeong Kim
- Department of Neurosurgery, Kyungpook National University Hospital, 50 Samduk-2-ga, Jung-gu, Daegu 700-721, Republic of Korea
| | - Dae-Chul Cho
- Department of Neurosurgery, Kyungpook National University Hospital, 50 Samduk-2-ga, Jung-gu, Daegu 700-721, Republic of Korea
| | - Jae-Sung Bae
- Department of Physiology, School of Medicine, Kyungpook National University, 680 Gukchaebosang-ro, Jung-gu, Daegu 700-842, Republic of Korea
| | - Seung-Won Park
- Department of Neurosurgery, College of Medicine, Chung-Ang University Hospital, 224-1 Heukseok dong, Dongjak-gu, Seoul 156-755, Republic of Korea
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28
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Hitomi M, Deleyrolle LP, Mulkearns-Hubert EE, Jarrar A, Li M, Sinyuk M, Otvos B, Brunet S, Flavahan WA, Hubert CG, Goan W, Hale JS, Alvarado AG, Zhang A, Rohaus M, Oli M, Vedam-Mai V, Fortin JM, Futch HS, Griffith B, Wu Q, Xia CH, Gong X, Ahluwalia MS, Rich JN, Reynolds BA, Lathia JD. Differential connexin function enhances self-renewal in glioblastoma. Cell Rep 2015; 11:1031-42. [PMID: 25959821 PMCID: PMC4502443 DOI: 10.1016/j.celrep.2015.04.021] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 03/10/2015] [Accepted: 04/07/2015] [Indexed: 12/17/2022] Open
Abstract
The coordination of complex tumor processes requires cells to rapidly modify their phenotype and is achieved by direct cell-cell communication through gap junction channels composed of connexins. Previous reports have suggested that gap junctions are tumor suppressive based on connexin 43 (Cx43), but this does not take into account differences in connexin-mediated ion selectivity and intercellular communication rate that drive gap junction diversity. We find that glioblastoma cancer stem cells (CSCs) possess functional gap junctions that can be targeted using clinically relevant compounds to reduce self-renewal and tumor growth. Our analysis reveals that CSCs express Cx46, while Cx43 is predominantly expressed in non-CSCs. During differentiation, Cx46 is reduced, while Cx43 is increased, and targeting Cx46 compromises CSC maintenance. The difference between Cx46 and Cx43 is reflected in elevated cell-cell communication and reduced resting membrane potential in CSCs. Our data demonstrate a pro-tumorigenic role for gap junctions that is dependent on connexin expression.
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Affiliation(s)
- Masahiro Hitomi
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44915, USA; Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44195, USA
| | - Loic P Deleyrolle
- Department of Neurosurgery, University of Florida, Gainesville, FL 32610-0261, USA
| | - Erin E Mulkearns-Hubert
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44915, USA
| | - Awad Jarrar
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44915, USA
| | - Meizhang Li
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44915, USA
| | - Maksim Sinyuk
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44915, USA
| | - Balint Otvos
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44915, USA
| | - Sylvain Brunet
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44915, USA
| | - William A Flavahan
- Department of Stem Cell Biology and Regenerative Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44915, USA
| | - Christopher G Hubert
- Department of Stem Cell Biology and Regenerative Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44915, USA
| | - Winston Goan
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44915, USA
| | - James S Hale
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44915, USA
| | - Alvaro G Alvarado
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44915, USA; Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44195, USA
| | - Ao Zhang
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44915, USA
| | - Mark Rohaus
- Department of Neurosurgery, University of Florida, Gainesville, FL 32610-0261, USA
| | - Muna Oli
- Department of Neurosurgery, University of Florida, Gainesville, FL 32610-0261, USA
| | - Vinata Vedam-Mai
- Department of Neurosurgery, University of Florida, Gainesville, FL 32610-0261, USA
| | - Jeff M Fortin
- Department of Neurosurgery, University of Florida, Gainesville, FL 32610-0261, USA
| | - Hunter S Futch
- Department of Neurosurgery, University of Florida, Gainesville, FL 32610-0261, USA
| | - Benjamin Griffith
- Department of Neurosurgery, University of Florida, Gainesville, FL 32610-0261, USA
| | - Qiulian Wu
- Department of Stem Cell Biology and Regenerative Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44915, USA
| | - Chun-Hong Xia
- Berkeley Stem Cell Center, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Xiaohua Gong
- Berkeley Stem Cell Center, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Manmeet S Ahluwalia
- Rose Ella Burkhardt Brain Tumor and Neuro Oncology Center, Cleveland Clinic, Cleveland, OH 44195, USA; Case Comprehensive Cancer Center, Cleveland, OH 44106, USA
| | - Jeremy N Rich
- Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44195, USA; Department of Stem Cell Biology and Regenerative Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44915, USA; Rose Ella Burkhardt Brain Tumor and Neuro Oncology Center, Cleveland Clinic, Cleveland, OH 44195, USA; Case Comprehensive Cancer Center, Cleveland, OH 44106, USA
| | - Brent A Reynolds
- Department of Neurosurgery, University of Florida, Gainesville, FL 32610-0261, USA.
| | - Justin D Lathia
- Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44915, USA; Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44195, USA; Rose Ella Burkhardt Brain Tumor and Neuro Oncology Center, Cleveland Clinic, Cleveland, OH 44195, USA; Case Comprehensive Cancer Center, Cleveland, OH 44106, USA.
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Phosphorylation of Connexin 43 by Cdk5 Modulates Neuronal Migration During Embryonic Brain Development. Mol Neurobiol 2015; 53:2969-2982. [DOI: 10.1007/s12035-015-9190-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Accepted: 04/22/2015] [Indexed: 11/25/2022]
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30
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Sart S, Bejarano FC, Baird MA, Yan Y, Rosenberg JT, Ma T, Grant SC, Li Y. Intracellular labeling of mouse embryonic stem cell–derived neural progenitor aggregates with micron-sized particles of iron oxide. Cytotherapy 2015; 17:98-111. [DOI: 10.1016/j.jcyt.2014.09.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 08/28/2014] [Accepted: 09/16/2014] [Indexed: 12/21/2022]
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31
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Aasen T. Connexins: junctional and non-junctional modulators of proliferation. Cell Tissue Res 2014; 360:685-99. [PMID: 25547217 DOI: 10.1007/s00441-014-2078-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2014] [Accepted: 11/14/2014] [Indexed: 12/11/2022]
Abstract
Mounting evidence indicates that dysregulation of gap junctions and their structural subunits-connexins-often occurs in, and sometimes causes, a variety of proliferative disorders, including cancer. Connexin-mediated regulation of cell proliferation is complex and may involve modulation of gap junction intercellular communication (GJIC), hemichannel signalling, or gap junction-independent paths. However, the exact mechanisms linking connexins to proliferation remain poorly defined and a number of contradictory studies report both pro- and anti-proliferative effects, effects that often depend on the cell or tissue type or the microenvironment. The present review covers junctional and non-junctional regulation of proliferation by connexins, with a particular emphasis on their association with cancer.
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Affiliation(s)
- Trond Aasen
- Molecular Pathology Group, Vall d'Hebron Institut de Recerca (VHIR), Universitat Autònoma de Barcelona, Passeig Vall d'Hebron 119-129, Barcelona, 08035, Spain,
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Hemodynamic forces regulate developmental patterning of atrial conduction. PLoS One 2014; 9:e115207. [PMID: 25503944 PMCID: PMC4264946 DOI: 10.1371/journal.pone.0115207] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Accepted: 11/19/2014] [Indexed: 02/01/2023] Open
Abstract
Anomalous action potential conduction through the atrial chambers of the heart can lead to severe cardiac arrhythmia. To date, however, little is known regarding the mechanisms that pattern proper atrial conduction during development. Here we demonstrate that atrial muscle functionally diversifies into at least two heterogeneous subtypes, thin-walled myocardium and rapidly conducting muscle bundles, during a developmental window just following cardiac looping. During this process, atrial muscle bundles become enriched for the fast conduction markers Cx40 and Nav1.5, similar to the precursors of the fast conduction Purkinje fiber network located within the trabeculae of the ventricles. In contrast to the ventricular trabeculae, however, atrial muscle bundles display an increased proliferation rate when compared to the surrounding myocardium. Interestingly, mechanical loading of the embryonic atrial muscle resulted in an induction of Cx40, Nav1.5 and the cell cycle marker Cyclin D1, while decreasing atrial pressure via in vivo ligation of the vitelline blood vessels results in decreased atrial conduction velocity. Taken together, these data establish a novel model for atrial conduction patterning, whereby hemodynamic stretch coordinately induces proliferation and fast conduction marker expression, which in turn promotes the formation of large diameter muscle bundles to serve as preferential routes of conduction.
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Kovács-Öller T, Raics K, Orbán J, Nyitrai M, Völgyi B. Developmental changes in the expression level of connexin36 in the rat retina. Cell Tissue Res 2014; 358:289-302. [PMID: 25110193 DOI: 10.1007/s00441-014-1967-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 07/09/2014] [Indexed: 02/03/2023]
Abstract
Connexin36 (Cx36) is the major gap junction forming protein in the brain and the retina; thus, alterations in its expression indicate changes in the corresponding circuitry. Many structural changes occur in the early postnatal retina before functional neuronal circuits are finalized, including those that incorporate gap junctions. To reveal the time-lapse formation of inner retinal gap junctions, we examine the developing postnatal rat retina from birth (P0) to young adult age (P20) and follow the expression of Cx36 in the mRNA and protein levels. We found a continuous elevation in the expression of both the Cx36 transcript and protein between P0 and P20 and a somewhat delayed Cx36 plaque formation throughout the inner plexiform layer (IPL) starting at P10. By using tristratificated calretinin positive (CaR(+)) fibers in the IPL as a guide, we detected a clear preference of Cx36 plaques for the ON sublamina from the earliest time of detection. This distributional preference became more pronounced at P15 and P20 due to the emergence and widespread expression of large (>0.1 μm(2)) Cx36 plaques in the ON sublamina. Finally, we showed that parvalbumin-positive (PV(+)) AII amacrine cell dendrites colocalize with Cx36 plaques as early as P10 in strata 3 and 4, whereas colocalizations in stratum 5 became characteristic only around P20. We conclude that Cx36 expression in the rat IPL displays a characteristic succession of changes during retinogenesis reflecting the formation of the underlying electrical synaptic circuitry. In particular, AII cell gap junctions, first formed with ON cone bipolar cells and later with other AII amacrine cells, accounted for the observed Cx36 expressional changes.
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Affiliation(s)
- Tamás Kovács-Öller
- Department of Experimental Zoology and Neurobiology, University of Pécs, Pécs, Ifjúság street 6, Hungary
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Samarasinghe RA, Kanuparthi PS, Timothy Greenamyre J, DeFranco DB, Di Maio R. Transient muscarinic and glutamatergic stimulation of neural stem cells triggers acute and persistent changes in differentiation. Neurobiol Dis 2014; 70:252-61. [PMID: 25003306 DOI: 10.1016/j.nbd.2014.06.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 06/24/2014] [Indexed: 11/27/2022] Open
Abstract
While aberrant cell proliferation and differentiation may contribute to epileptogenesis, the mechanisms linking an initial epileptic insult to subsequent changes in cell fate remain elusive. Using both mouse and human iPSC-derived neural progenitor/stem cells (NPSCs), we found that a combined transient muscarinic and mGluR1 stimulation inhibited overall neurogenesis but enhanced NPSC differentiation into immature GABAergic cells. If treated NPSCs were further passaged, they retained a nearly identical phenotype upon differentiation. A similar profusion of immature GABAergic cells was seen in rats with pilocarpine-induced chronic epilepsy. Furthermore, live cell imaging revealed abnormal de-synchrony of Ca(++) transients and altered gap junction intercellular communication following combined muscarinic/glutamatergic stimulation, which was associated with either acute site-specific dephosphorylation of connexin 43 or a long-term enhancement of its degradation. Therefore, epileptogenic stimuli can trigger acute and persistent changes in cell fate by altering distinct mechanisms that function to maintain appropriate intercellular communication between coupled NPSCs.
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Affiliation(s)
- Ranmal A Samarasinghe
- University of Pittsburgh School of Medicine, Department of Pharmacology and Chemical Biology, USA; University of California Los Angeles, Department of Neurology, USA.
| | - Prasad S Kanuparthi
- University of Pittsburgh School of Medicine, Department of Pharmacology and Chemical Biology, USA
| | - J Timothy Greenamyre
- University of Pittsburgh School of Medicine-Pittsburgh, Institute of Neurodegenerative Diseases, USA
| | - Donald B DeFranco
- University of Pittsburgh School of Medicine, Department of Pharmacology and Chemical Biology, USA.
| | - Roberto Di Maio
- University of Pittsburgh School of Medicine-Pittsburgh, Institute of Neurodegenerative Diseases, USA
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Muto T, Tien T, Kim D, Sarthy VP, Roy S. High glucose alters Cx43 expression and gap junction intercellular communication in retinal Müller cells: promotes Müller cell and pericyte apoptosis. Invest Ophthalmol Vis Sci 2014; 55:4327-37. [PMID: 24938518 DOI: 10.1167/iovs.14-14606] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
PURPOSE To investigate whether high glucose (HG) alters connexin 43 (Cx43) expression and gap junction intercellular communication (GJIC) activity in retinal Müller cells, and promotes Müller cell and pericyte loss. METHODS Retinal Müller cells (rMC-1) and cocultures of rMC-1 and retinal pericytes were grown in normal (N) or HG (30 mM glucose) medium. Additionally, rMC-1 transfected with Cx43 small interfering RNA (siRNA) were grown as cocultures with pericytes, and rMC-1 transfected with Cx43 plasmid were grown in HG. Expression of Cx43 was determined by Western blotting and immunostaining and GJIC was assessed by scrape-loading dye transfer (SLDT) technique. Apoptosis was analyzed by TUNEL or differential staining assay, and Akt activation by assessing Akt phosphorylation. RESULTS In monocultures of rMC-1 and cocultures of rMC-1 and pericytes, Cx43 protein level, number of Cx43 plaques, GJIC, and Akt phosphorylation were significantly reduced in HG medium. Number of TUNEL-positive cells was also significantly increased in rMC-1 monocultures and in rMC-1 and pericyte cocultures grown in HG medium. Importantly, when rMC-1 transfected with Cx43 siRNA were grown as cocultures with pericytes, a significant decrease in GJIC, and increase in TUNEL-positive cells was observed, concomitant with decreased Akt phosphorylation. Upregulation of Cx43 rescued rMC-1 from HG-induced apoptosis. CONCLUSIONS Gap junction communication between Müller cells and pericytes is essential for their survival. Downregulation of Cx43 that is HG induced and impairment of GJIC activity in Müller cells contributes to loss of glial and vascular cells associated with the pathogenesis of diabetic retinopathy.
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Affiliation(s)
- Tetsuya Muto
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States Department of Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States
| | - Thomas Tien
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States Department of Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States
| | - Dongjoon Kim
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States Department of Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States
| | - Vijay P Sarthy
- Department of Ophthalmology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
| | - Sayon Roy
- Department of Medicine, Boston University School of Medicine, Boston, Massachusetts, United States Department of Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States
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Talaverón R, Matarredona ER, de la Cruz RR, Macías D, Gálvez V, Pastor AM. Implanted neural progenitor cells regulate glial reaction to brain injury and establish gap junctions with host glial cells. Glia 2014; 62:623-38. [PMID: 24481572 DOI: 10.1002/glia.22630] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 12/20/2013] [Accepted: 12/23/2013] [Indexed: 01/19/2023]
Abstract
Transplantation of neural stem/progenitor cells (NPCs) in the lesioned brain is able to restore morphological and physiological alterations induced by different injuries. The local microenvironment created at the site of grafting and the communication between grafted and host cells are crucial in the beneficial effects attributed to the NPC implants. We have previously described that NPC transplantation in an animal model of central axotomy restores firing properties and synaptic coverage of lesioned neurons and modulates their trophic factor content. In this study, we aim to explore anatomical relationships between implanted NPCs and host glia that might account for the implant-induced neuroprotective effects. Postnatal rat subventricular zone NPCs were isolated and grafted in adult rats after transection of the medial longitudinal fascicle. Brains were removed and analyzed eight weeks later. Immunohistochemistry for different glial markers revealed that NPC-grafted animals displayed significantly greater microglial activation than animals that received only vehicle injections. Implanted NPCs were located in close apposition to activated microglia and reactive astrocytes. The gap junction protein connexin43 was present in NPCs and glial cells at the lesion site and was often found interposed within adjacent implanted and glial cells. Gap junctions were identified between implanted NPCs and host astrocytes and less frequently between NPCs and microglia. Our results show that implanted NPCs modulate the glial reaction to lesion and establish the possibility of communication through gap junctions between grafted and host glial cells which might be involved in the restorative effects of NPC implants.
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Affiliation(s)
- Rocío Talaverón
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
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Abstract
Oppositely directed projections of some homologous neurons in the developing CNS of the medicinal leech (Hirudo verbana), such as the AP cells, undergo a form of contact-dependent homolog avoidance. Embryonic APs extend axons within the connective nerve toward adjacent ganglia, in which they meet and form gap junctions (GJs) with the oppositely directed axons of their segmental homologs, stop growing, and are later permanently retracted (Wolszon et al., 1994a,b). However, early deletion of an AP neuron leads to resumed growth and permanent maintenance of the projections of neighboring APs. Here we test the hypothesis that a GJ-based signaling mechanism is responsible for this instance of homolog avoidance. We demonstrate that selective knockdown of GJ gene Hve-inx1 expression in single embryonic APs, by expressing a short-hairpin interfering RNA, leads to continued growth of the projections of the cell toward, into, and beyond adjacent ganglia. Moreover, the projections of the APs in adjacent ganglia also resume growth, mimicking their responses to cell deletion. Continued growth was also observed when two different INX1 mutant transgenes that abolish dye coupling between APs were expressed. These include a mutant transgene that effectively downregulates all GJ plaques that include the INX1 protein and a closed channel INX1 mutant that retains the adhesive cellular binding characteristic of INX1 GJs but not the open channel pore function. Our results add GJ intercellular communication to the list of molecular signaling mechanisms that can act as mediators of growth-inhibiting cell-cell interactions that define the topography of neuronal arbors.
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Lemcke H, Kuznetsov SA. Involvement of connexin43 in the EGF/EGFR signalling during self-renewal and differentiation of neural progenitor cells. Cell Signal 2013; 25:2676-84. [DOI: 10.1016/j.cellsig.2013.08.030] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 08/26/2013] [Accepted: 08/28/2013] [Indexed: 10/26/2022]
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Permeability transition pore-mediated mitochondrial superoxide flashes mediate an early inhibitory effect of amyloid beta1-42 on neural progenitor cell proliferation. Neurobiol Aging 2013; 35:975-89. [PMID: 24325797 DOI: 10.1016/j.neurobiolaging.2013.11.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 08/22/2013] [Accepted: 11/05/2013] [Indexed: 01/04/2023]
Abstract
Cellular damage by reactive oxygen species and altered neurogenesis are implicated in the etiology of AD and the pathogenic actions of amyloid β-peptide (Aβ); the underlying mechanisms and the early oxidative intracellular events triggered by Aβ are not established. In the present study, we found that mouse embryonic cortical neural progenitor cells exhibit intermittent spontaneous mitochondrial superoxide (SO) flashes that require transient opening of mitochondrial permeability transition pores (mPTPs). The incidence of mitochondria SO flash activity in neural progenitor cells (NPCs) increased during the first 6-24 hours of exposure to aggregating amyloid β-peptide (Aβ1-42), indicating an increase in transient mPTP opening. Subsequently, the SO flash frequency progressively decreased and ceased between 48 and 72 hours of exposure to Aβ1-42, during which time global cellular reactive oxygen species increased, mitochondrial membrane potential decreased, cytochrome C was released from mitochondria and the cells degenerated. Inhibition of mPTPs and selective reduction in mitochondrial SO flashes significantly ameliorated the negative effects of Aβ1-42 on NPC proliferation and survival. Our findings suggest that mPTP-mediated bursts of mitochondrial SO production is a relatively early and pivotal event in the adverse effects of Aβ1-42 on NPCs. If Aβ inhibits NPC proliferation in the brains of AD patients by a similar mechanism, then interventions that inhibit mPTP-mediated superoxide flashes would be expected to protect NPCs against the adverse effects of Aβ.
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Del Debbio CB, Peng X, Xiong H, Ahmad I. Adult ciliary epithelial stem cells generate functional neurons and differentiate into both early and late born retinal neurons under non-cell autonomous influences. BMC Neurosci 2013; 14:130. [PMID: 24148749 PMCID: PMC3856605 DOI: 10.1186/1471-2202-14-130] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 10/14/2013] [Indexed: 12/31/2022] Open
Abstract
Background The neural stem cells discovered in the adult ciliary epithelium (CE) in higher vertebrates have emerged as an accessible source of retinal progenitors; these cells can self-renew and possess retinal potential. However, recent studies have cast doubt as to whether these cells could generate functional neurons and differentiate along the retinal lineage. Here, we have systematically examined the pan neural and retinal potential of CE stem cells. Results Molecular and cellular analysis was carried out to examine the plasticity of CE stem cells, obtained from mice expressing green fluorescent protein (GFP) under the influence of the promoter of the rod photoreceptor-specific gene, Nrl, using the neurospheres assay. Differentiation was induced by specific culture conditions and evaluated by both transcripts and protein levels of lineage-specific regulators and markers. Temporal pattern of their levels were examined to determine the expression of genes and proteins underlying the regulatory hierarchy of cells specific differentiation in vitro. Functional attributes of differentiation were examined by the presence of current profiles and pharmacological mobilization of intracellular calcium using whole cell recordings and Fura-based calcium imaging, respectively. We demonstrate that stem cells in adult CE not only have the capacity to generate functional neurons, acquiring the expression of sodium and potassium channels, but also respond to specific cues in culture and preferentially differentiate along the lineages of retinal ganglion cells (RGCs) and rod photoreceptors, the early and late born retinal neurons, respectively. The retinal differentiation of CE stem cells was characterized by the temporal acquisition of the expression of the regulators of RGCs and rod photoreceptors, followed by the display of cell type-specific mature markers and mobilization of intracellular calcium. Conclusions Our study demonstrates the bonafide retinal potential of adult CE stem cells and suggests that their plasticity could be harnessed for clinical purposes once barriers associated with any lineage conversion, i.e., low efficiency and fidelity is overcome through the identification of conducive culture conditions.
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Affiliation(s)
| | | | | | - Iqbal Ahmad
- Department of Ophthalmology and Visual Sciences, University of Nebraska Medical Center, Durham Research Center 1, Room 4044, 985840 Nebraska Medical Center, Omaha, NE 68198-5840, USA.
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Wan CK, O'Carroll SJ, Kim SL, Green CR, Nicholson LFB. Spatiotemporal changes in Cx30 and Cx43 expression during neuronal differentiation of P19 EC and NT2/D1 cells. CELL BIOLOGY INTERNATIONAL REPORTS 2013; 20:13-23. [PMID: 25505515 PMCID: PMC4255794 DOI: 10.1002/cbi3.10005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 07/17/2013] [Indexed: 12/23/2022]
Abstract
While connexins (Cxs) are thought to be involved in differentiation, their expression and role has yet to be fully elucidated. We investigated the temporal expression of Cx30, Cx36 and Cx43 in two in vitro models of neuronal differentiation: human NT2/D1 and murine P19 cells, and the spatial localisation of Cx30 and Cx43 in these models. A temporal Cx43 downregulation was confirmed in both cell lines during RA-induced neuronal differentiation using RT-PCR (P < 0.05) preceding an increase in neuronal doublecortin protein. RT-PCR showed Cx36 was upregulated twofold in NT2/D1 cells (P < 0.05) and sixfold in P19 cells (P < 0.001) during neuronal differentiation. Cx30 exhibited a transient peak in expression midway through the timecourse of differentiation increasing threefold in NT2/D1 cells (P < 0.001) and eightfold in P19 cells (P < 0.01). Qualitative immunocytochemistry was used to examine spatiotemporal patterns of Cx protein distribution alongside neuronal differentiation markers. The temporal immunolabelling pattern was similar to that seen using RT-PCR. Cx43 was observed intracellularly and on cell surfaces, while Cx30 was seen as puncta. Spatially Cx43 was seen on doublecortin-negative cells, which may indicate Cx43 downregulation is requisite for differentiation in these models. Conversely, Cx30 puncta were observed on doublecortin-positive and -negative cells in NT2/D1 cells and examination of the Cx30 peak showed puncta also localized to nestin-positive cells, with few puncta on MAP2-positive cells. In P19 cells Cx30 was localized on clusters of cells surrounded by MAP2- and doublecortin-positive processes. The expression pattern of Cx30 indicates a role in neuronal differentiation; the nature of that role warrants future investigation.
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Affiliation(s)
- Carthur K Wan
- Faculty of Medical and Health Sciences, Department of Anatomy with Radiology and Centre for Brain Research, The University of Auckland Auckland, 92019, New Zealand
| | - Simon J O'Carroll
- Faculty of Medical and Health Sciences, Department of Anatomy with Radiology and Centre for Brain Research, The University of Auckland Auckland, 92019, New Zealand
| | - Sue-Ling Kim
- Faculty of Medical and Health Sciences, Department of Anatomy with Radiology and Centre for Brain Research, The University of Auckland Auckland, 92019, New Zealand
| | - Colin R Green
- Faculty of Medical and Health Sciences, Department of Ophthalmology, The University of Auckland Auckland, 92019, New Zealand
| | - Louise F B Nicholson
- Faculty of Medical and Health Sciences, Department of Anatomy with Radiology and Centre for Brain Research, The University of Auckland Auckland, 92019, New Zealand
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42
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Liebmann M, Stahr A, Guenther M, Witte OW, Frahm C. Astrocytic Cx43 and Cx30 differentially modulate adult neurogenesis in mice. Neurosci Lett 2013; 545:40-5. [DOI: 10.1016/j.neulet.2013.04.013] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 03/26/2013] [Accepted: 04/13/2013] [Indexed: 11/30/2022]
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43
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Lemcke H, Nittel ML, Weiss DG, Kuznetsov SA. Neuronal differentiation requires a biphasic modulation of gap junctional intercellular communication caused by dynamic changes of connexin43 expression. Eur J Neurosci 2013; 38:2218-28. [PMID: 23607708 DOI: 10.1111/ejn.12219] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 03/12/2013] [Accepted: 03/14/2013] [Indexed: 11/30/2022]
Abstract
It was suggested that gap junctional intercellular communication (GJIC) and connexin (Cx) proteins play a crucial role in cell proliferation and differentiation. However, the mechanisms of cell coupling in regulating cell fate during embryonic development are poorly understood. To study the role of GJIC in proliferation and differentiation, we used a human neural progenitor cell line derived from the ventral mesencephalon. Fluorescence recovery after photobleaching (FRAP) showed that dye coupling was extensive in proliferating cells but diminished after the induction of differentiation, as indicated by a 2.5-fold increase of the half-time of fluorescence recovery. Notably, recovery half-time decreased strongly (five-fold) in the later stage of differentiation. Western blot analysis revealed a similar time-dependent expression profile of Cx43, acting as the main gap junction-forming protein. Interestingly, large amounts of cytoplasmic Cx43 were retained mainly in the Golgi network during proliferation but decreased when differentiation was induced. Furthermore, down-regulation of Cx43 by small interfering RNA reduced functional cell coupling, which in turn resulted in a 50% decrease of both the proliferation rate and neuronal differentiation. Our findings suggest a dual function of Cx43 and GJIC in the neural development of ReNcell VM197 human progenitor cells. GJIC accompanied by high Cx43 expression is necessary (1) to maintain cells in a proliferative state and (2) to complete neuronal differentiation, including the establishment of a neural network. However, uncoupling of cells is crucial in the early stage of differentiation during cell fate commitment.
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Affiliation(s)
- Heiko Lemcke
- Department of Animal Physiology, Cell Biology and Biosystems Technology, Institute of Biological Sciences, University of Rostock, Albert-Einstein-Str. 3, D-18059, Rostock, Germany
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Goldberg JS, Vadakkan TJ, Hirschi KK, Dickinson ME. A computational approach to detect gap junction plaques and associate them with cells in fluorescent images. J Histochem Cytochem 2013; 61:283-93. [PMID: 23324867 DOI: 10.1369/0022155413477114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Intercellular signaling is a fundamental requirement for complex biological system function and survival. Communication between adjoining cells is largely achieved via gap junction channels made up of multiple subunits of connexin proteins, each with unique selectivity and regulatory properties. Intercellular communication via gap junction channels facilitates transmission of an array of cellular signals, including ions, macromolecules, and metabolites that coordinate physiological processes throughout tissues and entire organisms. Although current methods used to quantify connexin expression rely on number or area density measurements in a field of view, they lack cellular assignment, distance measurement capabilities (both within the cell and to extracellular structures), and complete automation. We devised an automated computational approach built on a contour expansion algorithm platform that allows connexin protein detection and assignment to specific cells within complex tissues. In addition, parallel implementation of the contour expansion algorithm allows for high-throughput analysis as the complexity of the biological sample increases. This method does not depend specifically on connexin identification and can be applied more widely to the analysis of numerous immunocytochemical markers as well as to identify particles within tissues such as nanoparticles, gene delivery vehicles, or even cellular fragments such as exosomes or microparticles.
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Affiliation(s)
- Joshua S Goldberg
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
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45
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Stoletov K, Strnadel J, Zardouzian E, Momiyama M, Park FD, Kelber JA, Pizzo DP, Hoffman R, VandenBerg SR, Klemke RL. Role of connexins in metastatic breast cancer and melanoma brain colonization. J Cell Sci 2013; 126:904-13. [PMID: 23321642 DOI: 10.1242/jcs.112748] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Breast cancer and melanoma cells commonly metastasize to the brain using homing mechanisms that are poorly understood. Cancer patients with brain metastases display poor prognosis and survival due to the lack of effective therapeutics and treatment strategies. Recent work using intravital microscopy and preclinical animal models indicates that metastatic cells colonize the brain, specifically in close contact with the existing brain vasculature. However, it is not known how contact with the vascular niche promotes microtumor formation. Here, we investigate the role of connexins in mediating early events in brain colonization using transparent zebrafish and chicken embryo models of brain metastasis. We provide evidence that breast cancer and melanoma cells utilize connexin gap junction proteins (Cx43, Cx26) to initiate brain metastatic lesion formation in association with the vasculature. RNAi depletion of connexins or pharmacological blocking of connexin-mediated cell-cell communication with carbenoxolone inhibited brain colonization by blocking tumor cell extravasation and blood vessel co-option. Activation of the metastatic gene twist in breast cancer cells increased Cx43 protein expression and gap junction communication, leading to increased extravasation, blood vessel co-option and brain colonization. Conversely, inhibiting twist activity reduced Cx43-mediated gap junction coupling and brain colonization. Database analyses of patient histories revealed increased expression of Cx26 and Cx43 in primary melanoma and breast cancer tumors, respectively, which correlated with increased cancer recurrence and metastasis. Together, our data indicate that Cx43 and Cx26 mediate cancer cell metastasis to the brain and suggest that connexins might be exploited therapeutically to benefit cancer patients with metastatic disease.
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Affiliation(s)
- Konstantin Stoletov
- Department of Pathology, University of California, San Diego, La Jolla, CA 92093, USA
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Eugenin EA, Basilio D, Sáez JC, Orellana JA, Raine CS, Bukauskas F, Bennett MVL, Berman JW. The role of gap junction channels during physiologic and pathologic conditions of the human central nervous system. J Neuroimmune Pharmacol 2012; 7:499-518. [PMID: 22438035 PMCID: PMC3638201 DOI: 10.1007/s11481-012-9352-5] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2012] [Accepted: 02/28/2012] [Indexed: 12/15/2022]
Abstract
Gap junctions (GJs) are expressed in most cell types of the nervous system, including neuronal stem cells, neurons, astrocytes, oligodendrocytes, cells of the blood brain barrier (endothelial cells and astrocytes) and under inflammatory conditions in microglia/macrophages. GJs connect cells by the docking of two hemichannels, one from each cell with each hemichannel being formed by 6 proteins named connexins (Cx). Unapposed hemichannels (uHC) also can be open on the surface of the cells allowing the release of different intracellular factors to the extracellular space. GJs provide a mechanism of cell-to-cell communication between adjacent cells that enables the direct exchange of intracellular messengers, such as calcium, nucleotides, IP(3), and diverse metabolites, as well as electrical signals that ultimately coordinate tissue homeostasis, proliferation, differentiation, metabolism, cell survival and death. Despite their essential functions in physiological conditions, relatively little is known about the role of GJs and uHC in human diseases, especially within the nervous system. The focus of this review is to summarize recent findings related to the role of GJs and uHC in physiologic and pathologic conditions of the central nervous system.
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Affiliation(s)
- Eliseo A Eugenin
- Department of Pathology, F727, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY 10461, USA.
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Yamashita M. From neuroepithelial cells to neurons: changes in the physiological properties of neuroepithelial stem cells. Arch Biochem Biophys 2012; 534:64-70. [PMID: 22892549 DOI: 10.1016/j.abb.2012.07.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2012] [Revised: 07/04/2012] [Accepted: 07/27/2012] [Indexed: 10/28/2022]
Abstract
The central nervous system, which includes the spinal cord, retina, and brain, is derived from the neural tube. The neural tube is formed of a sheet of cells called the neuroepithelium. During embryonic development, neuroepithelial cells function as neural stem cells: they renew themselves while undergoing interkinetic nuclear movements along the apico-basal axis during the cell cycle, and they produce postmitotic cells that function as newborn neurons. Neuroepithelial cells exhibit a robust increase in nucleoplasmic [Ca(2+)] in response to G protein-coupled receptor activation during S-phase when the nucleus is located in the basal region of the cell. This Ca(2+) rise is caused by the release of Ca(2+) from intracellular Ca(2+) stores, and the Ca(2+) release in turn activates Ca(2+) entry from the extracellular space, which is called capacitative (or store-operated) Ca(2+) entry. The Ca(2+) release and store-operated Ca(2+) entry are essential for DNA synthesis during S-phase. The activity of this store-operated Ca(2+) signaling system declines in parallel with the decreasing proliferative activity of neuroepithelial cells. When exiting the cell cycle, the cells lose the apical process where gap junctions are located. Following the loss of gap junction coupling, the postmitotic cells show a high input resistance, which allows them to be readily depolarized. The Ca(2+) response to the excitatory neurotransmitter glutamate appears and develops during neuronal differentiation. The glutamate-induced Ca(2+) rise increases transiently during natural cell death (apoptosis). The rise in Ca(2+) levels mediated by voltage-gated Ca(2+) channels also develops during neuronal differentiation. Thus, when neuroepithelial cells differentiate into neurons, a transition from a store-operated system to a voltage-operated system occurs in the main Ca(2+) signaling system. This transition may reflect a change in the mode of intercellular communication from a stored Ca(2+)-dependent mode to a plasma membrane potential-dependent mode.
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Affiliation(s)
- Masayuki Yamashita
- Department of Physiology 1, Nara Medical University, Shijo-cho 840, Kashihara, Japan.
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48
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Samarasinghe RA, Witchell SF, DeFranco DB. Cooperativity and complementarity: synergies in non-classical and classical glucocorticoid signaling. Cell Cycle 2012; 11:2819-27. [PMID: 22801547 DOI: 10.4161/cc.21018] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Glucocorticoids (GCs) are an ubiquitous class of steroid hormones that exert a wide array of physiological effects. Traditionally, GC action has been considered to primarily involve transcriptional effects following the binding of hormone to the glucocorticoid receptor (GR) and subsequent activation or repression of target genes. However, a number of findings suggest that cellular responses following GC exposure may be mediated by transcription-independent, or "non-classical," mechanisms. We have added to this growing body of work by recently uncovering a novel GC signaling pathway that operates through plasma membrane GRs to limit gap junction intercellular signaling and limit the proliferation of neural progenitor cells (NPCs). In this review, we highlight our current state of knowledge of non-classical GR signaling, in particular as it applies to neuronal function. Using NPCs as a cellular model, we speculate on the components of this non-classical pathway and the mechanisms whereby a number of cytoplasmic and nuclear signaling events may be integrated.
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Affiliation(s)
- Ranmal A Samarasinghe
- Department of Neuroscience, University of Pittsburgh, School of Medicine, and Department of Pediatrics, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, USA
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Hale JS, Li M, Lathia JD. The malignant social network: cell-cell adhesion and communication in cancer stem cells. Cell Adh Migr 2012; 6:346-55. [PMID: 22796941 DOI: 10.4161/cam.21294] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Tumors contain a vastly complicated cellular network that relies on local communication to execute malignant programs. The molecular cues that are involved in cell-cell adhesion orchestrate large-scale tumor behaviors such as proliferation and invasion. We have recently begun to appreciate that many tumors contain a high degree of cellular heterogeneity and are organized in a cellular hierarchy, with a cancer stem cell (CSC) population identified at the apex in multiple cancer types. CSCs reside in unique microenvironments or niches that are responsible for directing their behavior through cellular interactions between CSCs and stromal cells, generating a malignant social network. Identifying cell-cell adhesion mechanisms in this network has implications for the basic understanding of tumorigenesis and the development of more effective therapies. In this review, we will discuss our current understanding of cell-cell adhesion mechanisms used by CSCs and how these local interactions have global consequences for tumor biology.
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Affiliation(s)
- James S Hale
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
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Large Pore Ion and Metabolite-Permeable Channel Regulation of Postnatal Ventricular Zone Neural Stem and Progenitor Cells: Interplay between Aquaporins, Connexins, and Pannexins? Stem Cells Int 2012; 2012:454180. [PMID: 22754577 PMCID: PMC3382389 DOI: 10.1155/2012/454180] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Accepted: 04/27/2012] [Indexed: 12/17/2022] Open
Abstract
The birth of new neurons from unspecialized neural stem and progenitor cells surrounding the lateral ventricles occurs throughout postnatal life. This process, termed neurogenesis, is complex and multistepped, encompassing several types of cellular behaviours, such as proliferation, differentiation, and migration. These behaviours are influenced by numerous factors present in the unique, permissive microenvironment. A major cellular mechanism for sensing the plethora of environmental cues directing this process is the presence of different channel forming proteins spanning the plasma membrane. So-called large pore membrane channels, which are selective for the passage of specific types of small molecules and ions, are emerging as an important subgroup of channel proteins. Here, we focus on the roles of three such large pore channels, aquaporin 4, connexin 43, and pannexin 1. We highlight both their independent functions as well as the accumulating evidence for crosstalk between them.
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