1
|
Theophanous S, Sargiannidou I, Kleopa KA. Glial Cells as Key Regulators in Neuroinflammatory Mechanisms Associated with Multiple Sclerosis. Int J Mol Sci 2024; 25:9588. [PMID: 39273535 PMCID: PMC11395575 DOI: 10.3390/ijms25179588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2024] [Revised: 08/29/2024] [Accepted: 09/02/2024] [Indexed: 09/15/2024] Open
Abstract
Even though several highly effective treatments have been developed for multiple sclerosis (MS), the underlying pathological mechanisms and drivers of the disease have not been fully elucidated. In recent years, there has been a growing interest in studying neuroinflammation in the context of glial cell involvement as there is increasing evidence of their central role in disease progression. Although glial cell communication and proper function underlies brain homeostasis and maintenance, their multiple effects in an MS brain remain complex and controversial. In this review, we aim to provide an overview of the contribution of glial cells, oligodendrocytes, astrocytes, and microglia in the pathology of MS during both the activation and orchestration of inflammatory mechanisms, as well as of their synergistic effects during the repair and restoration of function. Additionally, we discuss how the understanding of glial cell involvement in MS may provide new therapeutic targets either to limit disease progression or to facilitate repair.
Collapse
Affiliation(s)
- Styliani Theophanous
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, 2371 Nicosia, Cyprus
| | - Irene Sargiannidou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, 2371 Nicosia, Cyprus
| | - Kleopas A Kleopa
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, 2371 Nicosia, Cyprus
- Center for Multiple Sclerosis and Related Disorders, The Cyprus Institute of Neurology and Genetics, 2371 Nicosia, Cyprus
| |
Collapse
|
2
|
Díaz-Zaragoza M, Hernández-Ávila R, Landa A, Ostoa-Saloma P. Variation of the 2D Pattern of Brain Proteins in Mice Infected with Taenia crassiceps ORF Strain. Int J Mol Sci 2024; 25:1460. [PMID: 38338740 PMCID: PMC10855729 DOI: 10.3390/ijms25031460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Revised: 01/12/2024] [Accepted: 01/22/2024] [Indexed: 02/12/2024] Open
Abstract
Some parasites are known to influence brain proteins or induce changes in the functioning of the nervous system. In this study, our objective is to demonstrate how the two-dimensional gel technique is valuable for detecting differences in protein expression and providing detailed information on changes in the brain proteome during a parasitic infection. Subsequently, we seek to understand how the parasitic infection affects the protein composition in the brain and how this may be related to changes in brain function. By analyzing de novo-expressed proteins at 2, 4, and 8 weeks post-infection compared to the brains of the control mice, we observed that proteins expressed at 2 weeks are primarily associated with neuroprotection or the initial response of the mouse brain to the infection. At 8 weeks, parasitic infection can induce oxidative stress in the brain, potentially activating signaling pathways related to the response to cellular damage. Proteins expressed at 8 weeks exhibit a pattern indicating that, as the host fails to balance the Neuro-Immuno-Endocrine network of the organism, the brain begins to undergo an apoptotic process and consequently experiences brain damage.
Collapse
Affiliation(s)
- Mariana Díaz-Zaragoza
- Departamento de Ciencias de la Salud, Centro Universitario de los Valles, Universidad de Guadalajara, Carretera Guadalajara-Ameca Km. 45.5, Guadalajara 46600, Mexico;
| | - Ricardo Hernández-Ávila
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, A.P. 70228, Mexico City 04510, Mexico;
| | - Abraham Landa
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad Universitaria, A.P. 70228, Mexico City 04510, Mexico;
| | - Pedro Ostoa-Saloma
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, A.P. 70228, Mexico City 04510, Mexico;
| |
Collapse
|
3
|
Pechlivanidou M, Kousiappa I, Angeli S, Sargiannidou I, Koupparis AM, Papacostas SS, Kleopa KA. Glial Gap Junction Pathology in the Spinal Cord of the 5xFAD Mouse Model of Early-Onset Alzheimer's Disease. Int J Mol Sci 2022; 23:15597. [PMID: 36555237 PMCID: PMC9779687 DOI: 10.3390/ijms232415597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 11/22/2022] [Accepted: 12/02/2022] [Indexed: 12/13/2022] Open
Abstract
Gap junctions (GJs) are specialized transmembrane channels assembled by two hemi-channels of six connexin (Cx) proteins that facilitate neuroglial crosstalk in the central nervous system (CNS). Previous studies confirmed the crucial role of glial GJs in neurodegenerative disorders with dementia or motor dysfunction including Alzheimer's disease (AD). The aim of this study was to examine the alterations in astrocyte and related oligodendrocyte GJs in association with Aβ plaques in the spinal cord of the 5xFAD mouse model of AD. Our analysis revealed abundant Aβ plaque deposition, activated microglia, and astrogliosis in 12-month-old (12M) 5xFAD mice, with significant impairment of motor performance starting from 3-months (3M) of age. Additionally, 12M 5xFAD mice displayed increased immunoreactivity of astroglial Cx43 and Cx30 surrounding Aβ plaques and higher protein levels, indicating upregulated astrocyte-to-astrocyte GJ connectivity. In addition, they demonstrated increased numbers of mature CC1-positive and precursor oligodendrocytes (OPCs) with higher immunoreactivity of Cx47-positive GJs in individual cells. Moreover, total Cx47 protein levels were significantly elevated in 12M 5xFAD, reflecting increased oligodendrocyte-to-oligodendrocyte Cx47-Cx47 GJ connectivity. In contrast, we observed a marked reduction in Cx32 protein levels in 12M 5xFAD spinal cords compared with controls, while qRT-PCR analysis revealed a significant upregulation in Cx32 mRNA levels. Finally, myelin deficits were found focally in the areas occupied by Aβ plaques, whereas axons themselves remained preserved. Overall, our data provide novel insights into the altered glial GJ expression in the spinal cord of the 5xFAD model of AD and the implicated role of GJ pathology in neurodegeneration. Further investigation to understand the functional consequences of these extensive alterations in oligodendrocyte-astrocyte (O/A) GJ connectivity is warranted.
Collapse
Affiliation(s)
- Maria Pechlivanidou
- Neurobiology Department, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
| | - Ioanna Kousiappa
- Neurobiology Department, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
| | - Stella Angeli
- Medical School, University of Nicosia, Nicosia 2414, Cyprus
| | - Irene Sargiannidou
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
| | - Andreas M. Koupparis
- Neurobiology Department, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
- Epilepsy Centre, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
- Dementia and Cognitive Disorders Centre, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
| | - Savvas S. Papacostas
- Neurobiology Department, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
- Medical School, University of Nicosia, Nicosia 2414, Cyprus
- Epilepsy Centre, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
- Dementia and Cognitive Disorders Centre, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
| | - Kleopas A. Kleopa
- Neuroscience Department, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
- Center for Neuromuscular Disorders, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
- Center for Multiple Sclerosis and Related Disorders, The Cyprus Institute of Neurology and Genetics, Nicosia 2371, Cyprus
| |
Collapse
|
4
|
Papaneophytou C, Georgiou E, Kleopa KA. The role of oligodendrocyte gap junctions in neuroinflammation. Channels (Austin) 2020; 13:247-263. [PMID: 31232168 PMCID: PMC6602578 DOI: 10.1080/19336950.2019.1631107] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Gap junctions (GJs) provide channels for direct cell-to-cell connectivity serving the homeostasis in several organs of vertebrates including the central (CNS) and peripheral (PNS) nervous systems. GJs are composed of connexins (Cx), which show a highly distinct cellular and subcellular expression pattern. Oligodendrocytes, the myelinating cells of the CNS, are characterized by extensive GJ connectivity with each other as well as with astrocytes. The main oligodendrocyte connexins forming these GJ channels are Cx47 and Cx32. The importance of these channels has been highlighted by the discovery of human diseases caused by mutations in oligodendrocyte connexins, manifesting with leukodystrophy or transient encephalopathy. Experimental models have provided further evidence that oligodendrocyte GJs are essential for CNS myelination and homeostasis, while a strong inflammatory component has been recognized in the absence of oligodendrocyte connexins. Further studies revealed that connexins are also disrupted in multiple sclerosis (MS) brain, and in experimental models of induced inflammatory demyelination. Moreover, induced demyelination was more severe and associated with higher degree of CNS inflammation in models with oligodendrocyte GJ deficiency, suggesting that disrupted connexin expression in oligodendrocytes is not only a consequence but can also drive a pro-inflammatory environment in acquired demyelinating disorders such as MS. In this review, we summarize the current insights from human disorders as well as from genetic and acquired models of demyelination related to oligodendrocyte connexins, with the remaining challenges and perspectives.
Collapse
Affiliation(s)
- Christos Papaneophytou
- a Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine , Nicosia , Cyprus.,b Department of Life and Health Sciences, School of Sciences and Engineering , University of Nicosia , Nicosia , Cyprus
| | - Elena Georgiou
- a Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine , Nicosia , Cyprus
| | - Kleopas A Kleopa
- a Neuroscience Laboratory, The Cyprus Institute of Neurology and Genetics and Cyprus School of Molecular Medicine , Nicosia , Cyprus.,c Neurology Clinics , the Cyprus Institute of Neurology and Genetics, and the Cyprus School of Molecular Medicine , Nicosia , Cyprus
| |
Collapse
|
5
|
Xia CY, Xu JK, Pan CH, Lian WW, Yan Y, Ma BZ, He J, Zhang WK. Connexins in oligodendrocytes and astrocytes: Possible factors for demyelination in multiple sclerosis. Neurochem Int 2020; 136:104731. [PMID: 32201280 DOI: 10.1016/j.neuint.2020.104731] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 03/18/2020] [Accepted: 03/18/2020] [Indexed: 12/13/2022]
Abstract
Increasing evidences support that glial connexins are involved in the demyelination pathology of multiple sclerosis (MS), a chronic inflammatory demyelinating disorder. Here, we review the data from patients with MS and animal models of MS that implicate connexins in demyelination. Connexins expressed in oligodendrocytes and astrocytes show diverse changes at the different phases of MS. Loss of oligodendrocyte or astrocyte connexins contributes to demyelination and exaggerates the pathology of MS. Channel-dependent and -independent connexins are involved in the pathology of demyelination, which is related with myelin integrity, metabolic homeostasis, the brain-blood barrier, the immune cell infiltration, and the inflammatory response. A comprehensive understanding of connexin function in demyelination may provide new therapeutic targets for MS.
Collapse
Affiliation(s)
- Cong-Yuan Xia
- Department of Pharmacy & Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, 100029, People's Republic of China
| | - Jie-Kun Xu
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing, 100029, People's Republic of China
| | - Chen-Hao Pan
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing, 100029, People's Republic of China
| | - Wen-Wen Lian
- Department of Pharmacy & Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, 100029, People's Republic of China
| | - Yu Yan
- Department of Pharmacy & Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, 100029, People's Republic of China
| | - Bing-Zhi Ma
- Department of Pharmacy & Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, 100029, People's Republic of China
| | - Jun He
- Department of Pharmacy & Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, 100029, People's Republic of China.
| | - Wei-Ku Zhang
- Department of Pharmacy & Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing, 100029, People's Republic of China.
| |
Collapse
|
6
|
Habermacher C, Angulo MC, Benamer N. Glutamate versus GABA in neuron-oligodendroglia communication. Glia 2019; 67:2092-2106. [PMID: 30957306 DOI: 10.1002/glia.23618] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 02/28/2019] [Accepted: 03/19/2019] [Indexed: 12/20/2022]
Abstract
In the central nervous system (CNS), myelin sheaths around axons are formed by glial cells named oligodendrocytes (OLs). In turn, OLs are generated by oligodendrocyte precursor cells (OPCs) during postnatal development and in adults, according to a process that depends on the proliferation and differentiation of these progenitors. The maturation of OL lineage cells as well as myelination by OLs are complex and highly regulated processes in the CNS. OPCs and OLs express an array of receptors for neurotransmitters, in particular for the two main CNS neurotransmitters glutamate and GABA, and are therefore endowed with the capacity to respond to neuronal activity. Initial studies in cell cultures demonstrated that both glutamate and GABA signaling mechanisms play important roles in OL lineage cell development and function. However, much remains to be learned about the communication of glutamatergic and GABAergic neurons with oligodendroglia in vivo. This review focuses on recent major advances in our understanding of the neuron-oligodendroglia communication mediated by glutamate and GABA in the CNS, and highlights the present controversies in the field. We discuss the expression, activation modes and potential roles of synaptic and extrasynaptic receptors along OL lineage progression. We review the properties of OPC synaptic connectivity with presynaptic glutamatergic and GABAergic neurons in the brain and consider the implication of glutamate and GABA signaling in activity-driven adaptive myelination.
Collapse
Affiliation(s)
- Chloé Habermacher
- Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266, Paris, France.,Université Paris Descartes, Paris, France
| | - María C Angulo
- Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266, Paris, France.,Université Paris Descartes, Paris, France
| | - Najate Benamer
- Institute of Psychiatry and Neuroscience of Paris (IPNP), INSERM U1266, Paris, France.,Université Paris Descartes, Paris, France
| |
Collapse
|
7
|
Cisterna BA, Arroyo P, Puebla C. Role of Connexin-Based Gap Junction Channels in Communication of Myelin Sheath in Schwann Cells. Front Cell Neurosci 2019; 13:69. [PMID: 30881289 PMCID: PMC6405416 DOI: 10.3389/fncel.2019.00069] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Accepted: 02/12/2019] [Indexed: 12/21/2022] Open
Abstract
Peripheral nerves have the capacity to conduct action potentials along great distances and quickly recover following damage which is mainly due to Schwann cells (SCs), the most abundant glial cells of the peripheral nervous system (PNS). SCs wrap around an axonal segment multiple times, forming a myelin sheath, allowing for a significant increase in action potential conduction by insulating the axons. Mature myelin consists of compact and non-compact (or cytoplasmic) myelin zones. Non-compact myelin is found in paranodal loops bordering the nodes of Ranvier, and in the inner and outermost cytoplasmic tongues and is the region in which Schmidt-Lanterman incisures (SLI; continuous spirals of overlapping cytoplasmic expansions within areas of compact myelin) are located. Using different technologies, it was shown that the layers of non-compact myelin could be connected to each other by gap junction channels (GJCs), formed by connexin 32 (Cx32), and their relative abundance allows for the transfer of ions and different small molecules. Likewise, Cx29 is expressed in the innermost layer of the myelin sheath. Here it does not form GJCs but colocalizes with Kv1, which implies that the SCs play an active role in the electrical condition in mammals. The critical role of GJCs in the functioning of myelinating SCs is evident in Charcot-Marie-Tooth disease (CMT), X-linked form 1 (CMTX1), which is caused by mutations in the gap junction protein beta 1 (GJB1) gene that codes for Cx32. Although the management of CMT symptoms is currently supportive, there is a recent method for targeted gene delivery to myelinating cells, which rescues the phenotype in KO-Cx32 mice, a model of CMTX1. In this mini-review article, we discuss the current knowledge on the role of Cxs in myelin-forming SCs and summarize recent discoveries that may become a real treatment possibility for patients with disorders such as CMT.
Collapse
Affiliation(s)
- Bruno A Cisterna
- Escuela de Medicina, Universidad de Talca, Talca, Chile.,Centro para el Desarrollo de la Nanociencia y Nanotecnología (CEDENNA), Universidad de Santiago de Chile, Santiago, Chile
| | - Pablo Arroyo
- Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Carlos Puebla
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile
| |
Collapse
|
8
|
Vejar S, Oyarzún JE, Retamal MA, Ortiz FC, Orellana JA. Connexin and Pannexin-Based Channels in Oligodendrocytes: Implications in Brain Health and Disease. Front Cell Neurosci 2019; 13:3. [PMID: 30760982 PMCID: PMC6361860 DOI: 10.3389/fncel.2019.00003] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 01/07/2019] [Indexed: 11/13/2022] Open
Abstract
Oligodendrocytes are the myelin forming cells in the central nervous system (CNS). In addition to this main physiological function, these cells play key roles by providing energy substrates to neurons as well as information required to sustain proper synaptic transmission and plasticity at the CNS. The latter requires a fine coordinated intercellular communication with neurons and other glial cell types, including astrocytes. In mammals, tissue synchronization is mainly mediated by connexins and pannexins, two protein families that underpin the communication among neighboring cells through the formation of different plasma membrane channels. At one end, gap junction channels (GJCs; which are exclusively formed by connexins in vertebrates) connect the cytoplasm of contacting cells allowing electrical and metabolic coupling. At the other end, hemichannels and pannexons (which are formed by connexins and pannexins, respectively) communicate the intra- and extracellular compartments, serving as diffusion pathways of ions and small molecules. Here, we briefly review the current knowledge about the expression and function of hemichannels, pannexons and GJCs in oligodendrocytes, as well as the evidence regarding the possible role of these channels in metabolic and synaptic functions at the CNS. In particular, we focus on oligodendrocyte-astrocyte coupling during axon metabolic support and its implications in brain health and disease.
Collapse
Affiliation(s)
- Sebastián Vejar
- Mechanisms of Myelin Formation and Repair Laboratory, Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile
| | - Juan E. Oyarzún
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Investigación y Estudio del Consumo de Alcohol en Adolescentes, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Mauricio A. Retamal
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo, Santiago, Chile
- Department of Cell Physiology and Molecular Biophysics, and Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, United States
| | - Fernando C. Ortiz
- Mechanisms of Myelin Formation and Repair Laboratory, Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile
| | - Juan A. Orellana
- Departamento de Neurología, Escuela de Medicina and Centro Interdisciplinario de Neurociencias, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
- Centro de Investigación y Estudio del Consumo de Alcohol en Adolescentes, Pontificia Universidad Católica de Chile, Santiago, Chile
| |
Collapse
|
9
|
Jeon SJ, Ryu JH, Bahn GH. Altered Translational Control of Fragile X Mental Retardation Protein on Myelin Proteins in Neuropsychiatric Disorders. Biomol Ther (Seoul) 2017; 25:231-238. [PMID: 27829268 PMCID: PMC5424632 DOI: 10.4062/biomolther.2016.042] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Revised: 06/28/2016] [Accepted: 07/28/2016] [Indexed: 01/07/2023] Open
Abstract
Myelin is a specialized structure of the nervous system that both enhances electrical conductance and insulates neurons from external risk factors. In the central nervous system, polarized oligodendrocytes form myelin by wrapping processes in a spiral pattern around neuronal axons through myelin-related gene regulation. Since these events occur at a distance from the cell body, post-transcriptional control of gene expression has strategic advantage to fine-tune the overall regulation of protein contents in situ. Therefore, many research interests have been focused to identify RNA binding proteins and their regulatory mechanism in myelinating compartments. Fragile X mental retardation protein (FMRP) is one such RNA binding protein, regulating its target expression by translational control. Although the majority of works on FMRP have been performed in neurons, it is also found in the developing or mature glial cells including oligodendrocytes, where its function is not well understood. Here, we will review evidences suggesting abnormal translational regulation of myelin proteins with accompanying white matter problem and neurological deficits in fragile X syndrome, which can have wider mechanistic and pathological implication in many other neurological and psychiatric disorders.
Collapse
Affiliation(s)
- Se Jin Jeon
- Department of Life and Nanopharmaceutical Science, College of Pharmacy, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Jong Hoon Ryu
- Department of Life and Nanopharmaceutical Science, College of Pharmacy, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Geon Ho Bahn
- Department of Neuropsychiatry, School of Medicine, Kyung Hee University, Seoul 02447, Republic of Korea
| |
Collapse
|
10
|
von Bernhardi R, Eugenín-von Bernhardi J, Flores B, Eugenín León J. Glial Cells and Integrity of the Nervous System. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 949:1-24. [PMID: 27714682 DOI: 10.1007/978-3-319-40764-7_1] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Today, there is enormous progress in understanding the function of glial cells, including astroglia, oligodendroglia, Schwann cells, and microglia. Around 150 years ago, glia were viewed as a glue among neurons. During the course of the twentieth century, microglia were discovered and neuroscientists' views evolved toward considering glia only as auxiliary cells of neurons. However, over the last two to three decades, glial cells' importance has been reconsidered because of the evidence on their involvement in defining central nervous system architecture, brain metabolism, the survival of neurons, development and modulation of synaptic transmission, propagation of nerve impulses, and many other physiological functions. Furthermore, increasing evidence shows that glia are involved in the mechanisms of a broad spectrum of pathologies of the nervous system, including some psychiatric diseases, epilepsy, and neurodegenerative diseases to mention a few. It appears safe to say that no neurological disease can be understood without considering neuron-glia crosstalk. Thus, this book aims to show different roles played by glia in the healthy and diseased nervous system, highlighting some of their properties while considering that the various glial cell types are essential components not only for cell function and integration among neurons, but also for the emergence of important brain homeostasis.
Collapse
Affiliation(s)
- Rommy von Bernhardi
- Department of Neurology, School of Medicine, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile.
| | - Jaime Eugenín-von Bernhardi
- Physiological Genomics, Biomedical Center, Ludwig-Maximilians-University, Pettenkoferstr.12, 80336, Munich, Germany.,Graduate School of Systemic Neuroscience, Ludwig-Maximilians-University, 82152, Planegg-Martinsried, Munich, Germany
| | - Betsi Flores
- Department of Neurology, School of Medicine, Pontificia Universidad Católica de Chile, Marcoleta 391, Santiago, Chile
| | - Jaime Eugenín León
- Department of Biology, Faculty of Chemistry and Biology, USACH, Santiago, Chile
| |
Collapse
|
11
|
Theotokis P, Kleopa KA, Touloumi O, Lagoudaki R, Lourbopoulos A, Nousiopoulou E, Kesidou E, Poulatsidou KN, Dardiotis E, Hadjigeorgiou G, Karacostas D, Cifuentes-Diaz C, Irinopoulou T, Grigoriadis N. Connexin43 and connexin47 alterations after neural precursor cells transplantation in experimental autoimmune encephalomyelitis. Glia 2015; 63:1772-83. [PMID: 25914045 DOI: 10.1002/glia.22843] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 03/31/2015] [Accepted: 04/02/2015] [Indexed: 01/19/2023]
Abstract
Exogenous transplanted neural precursor cells (NPCs) exhibit miscellaneous immune-modulatory effects in models of autoimmune demyelination. However, the regional interactions of NPCs with the host brain tissue in remissive inflammatory events have not been adequately studied. In this study we used the chronic MOG-induced Experimental Autoimmune Encephalomyelitis (EAE) model in C57BL/six mice. Based on previous data, we focused on neuropathology at Day 50 post-induction (D50) and studied the expression of connexin43 (Cx43) and Cx47, two of the main glial gap junction (GJ) proteins, in relation to the intraventricular transplantation of GFP(+) NPCs and their integration with the host tissue. By D50, NPCs had migrated intraparenchymally and were found in the corpus callosum at the level of the lateral ventricles and hippocampus. The majority of GFP(+) cells differentiated with simple or ramified processes expressing mainly markers of mature GLIA (GFAP and NogoA) and significantly less of precursor glial cells. GFP(+) NPCs expressed connexins and formed GJs around the hippocampus more than lateral ventricles. The presence of NPCs did not alter the increase in Cx43 GJ plaques at D50 EAE, but prevented the reduction of oligodendrocytic Cx47, increased the number of oligodendrocytes, local Cx47 levels and Cx47 GJ plaques per cell. These findings suggest that transplanted NPCs may have multiple effects in demyelinating pathology, including differentiation and direct integration into the panglial syncytium, as well as amelioration of oligodendrocyte GJ loss, increasing the supply of potent myelinating cells to the demyelinated tissue.
Collapse
Affiliation(s)
- Paschalis Theotokis
- B' Department of Neurology, Laboratory of Experimental Neurology and Neuroimmunology, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Macedonia, Greece
| | - Kleopas A Kleopa
- Neurology Clinics and Neuroscience Laboratory, the Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | - Olga Touloumi
- B' Department of Neurology, Laboratory of Experimental Neurology and Neuroimmunology, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Macedonia, Greece
| | - Roza Lagoudaki
- B' Department of Neurology, Laboratory of Experimental Neurology and Neuroimmunology, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Macedonia, Greece
| | - Athanasios Lourbopoulos
- B' Department of Neurology, Laboratory of Experimental Neurology and Neuroimmunology, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Macedonia, Greece
| | - Evangelia Nousiopoulou
- B' Department of Neurology, Laboratory of Experimental Neurology and Neuroimmunology, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Macedonia, Greece
| | - Evangelia Kesidou
- B' Department of Neurology, Laboratory of Experimental Neurology and Neuroimmunology, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Macedonia, Greece
| | - Kyriaki-Nepheli Poulatsidou
- B' Department of Neurology, Laboratory of Experimental Neurology and Neuroimmunology, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Macedonia, Greece
| | - Efthimios Dardiotis
- Department of Neurology, Faculty of Medicine, University of Thessaly, Larissa, Greece
| | | | - Dimitris Karacostas
- B' Department of Neurology, Laboratory of Experimental Neurology and Neuroimmunology, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Macedonia, Greece
| | | | | | - Nikolaos Grigoriadis
- B' Department of Neurology, Laboratory of Experimental Neurology and Neuroimmunology, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Macedonia, Greece
| |
Collapse
|
12
|
Goncharenko K, Eftekharpour E, Velumian AA, Carlen PL, Fehlings MG. Changes in gap junction expression and function following ischemic injury of spinal cord white matter. J Neurophysiol 2014; 112:2067-75. [PMID: 25080569 DOI: 10.1152/jn.00037.2013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Gap junctions are widely present in spinal cord white matter; however, their role in modulating the dynamics of axonal dysfunction remains largely unexplored. We hypothesized that inhibition of gap junctions reduces the loss of axonal function during oxygen and glucose deprivation (OGD). The functional role of gap junctions was assessed by electrophysiological recordings of compound action potentials (CAPs) in Wistar rat spinal cord slices with the sucrose gap technique. The in vitro slices were subjected to 30-min OGD. Gap junction connexin (Cx) mRNA expression was determined by qPCR and normalized to β-actin. A 30-min OGD resulted in reduction of CAPs to 14.8 ± 4.6% of their pre-OGD amplitude (n = 5). In the presence of gap junction blockers carbenoxolone (Cbx; 100 μM) and 1-octanol (Oct; 300 μM), the CAP reduction in OGD was to only 35.7 ± 5.7% of pre-OGD amplitude in Cbx (n = 9) and to 37.4 ± 8.9% of pre-OGD amplitude in Oct (n = 10). Both drugs also noticeably prolonged the half-decline time of CAP amplitudes in OGD from 6.0 min in no-drug conditions to 9.6 min in the presence of Cbx and to 7.7 min in the presence of Oct, suggesting that blocking gap junctions reduces conduction loss during OGD. With application of Cbx and Oct in the setting of OGD, expression of Cx30 and Cx43 mRNA was downregulated. Our data provide new insights into the role of gap junctions in white matter ischemia and reveal the necessity of a cautious approach in determining detrimental or beneficial effects of gap junction blockade in white matter ischemia.
Collapse
Affiliation(s)
- Karina Goncharenko
- Division of Neurosurgery and Division of Genetics and Development, Toronto Western Research Institute, Krembil Neuroscience Centre, University Health Network and University of Toronto, Toronto, Ontario, Canada; Departments of Physiology and
| | - Eftekhar Eftekharpour
- Division of Neurosurgery and Division of Genetics and Development, Toronto Western Research Institute, Krembil Neuroscience Centre, University Health Network and University of Toronto, Toronto, Ontario, Canada
| | - Alexander A Velumian
- Division of Neurosurgery and Division of Genetics and Development, Toronto Western Research Institute, Krembil Neuroscience Centre, University Health Network and University of Toronto, Toronto, Ontario, Canada; Departments of Physiology and Surgery, University of Toronto, Toronto, Ontario, Canada
| | - Peter L Carlen
- Division of Neurosurgery and Division of Genetics and Development, Toronto Western Research Institute, Krembil Neuroscience Centre, University Health Network and University of Toronto, Toronto, Ontario, Canada; Departments of Physiology and
| | - Michael G Fehlings
- Division of Neurosurgery and Division of Genetics and Development, Toronto Western Research Institute, Krembil Neuroscience Centre, University Health Network and University of Toronto, Toronto, Ontario, Canada; Surgery, University of Toronto, Toronto, Ontario, Canada
| |
Collapse
|
13
|
Reyes EP, Cerpa V, Corvalán L, Retamal MA. Cxs and Panx- hemichannels in peripheral and central chemosensing in mammals. Front Cell Neurosci 2014; 8:123. [PMID: 24847209 PMCID: PMC4023181 DOI: 10.3389/fncel.2014.00123] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 04/18/2014] [Indexed: 01/08/2023] Open
Abstract
Connexins (Cxs) and Pannexins (Panx) form hemichannels at the plasma membrane of animals. Despite their low open probability under physiological conditions, these hemichannels release signaling molecules (i.e., ATP, Glutamate, PGE2) to the extracellular space, thus subserving several important physiological processes. Oxygen and CO2 sensing are fundamental to the normal functioning of vertebrate organisms. Fluctuations in blood PO2, PCO2 and pH are sensed at the carotid bifurcations of adult mammals by glomus cells of the carotid bodies. Likewise, changes in pH and/or PCO2 of cerebrospinal fluid are sensed by central chemoreceptors, a group of specialized neurones distributed in the ventrolateral medulla (VLM), raphe nuclei, and some other brainstem areas. After many years of research, the molecular mechanisms involved in chemosensing process are not completely understood. This manuscript will review data regarding relationships between chemosensitive cells and the expression of channels formed by Cxs and Panx, with special emphasis on hemichannels.
Collapse
Affiliation(s)
- Edison Pablo Reyes
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo Santiago, Chile ; Dirección de Investigación, Universidad Autónoma de Chile Santiago, Chile
| | - Verónica Cerpa
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo Santiago, Chile
| | - Liliana Corvalán
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo Santiago, Chile
| | - Mauricio Antonio Retamal
- Centro de Fisiología Celular e Integrativa, Facultad de Medicina, Clínica Alemana Universidad del Desarrollo Santiago, Chile
| |
Collapse
|
14
|
Kurtenbach S, Kurtenbach S, Zoidl G. Gap junction modulation and its implications for heart function. Front Physiol 2014; 5:82. [PMID: 24578694 PMCID: PMC3936571 DOI: 10.3389/fphys.2014.00082] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 02/10/2014] [Indexed: 01/04/2023] Open
Abstract
Gap junction communication (GJC) mediated by connexins is critical for heart function. To gain insight into the causal relationship of molecular mechanisms of disease pathology, it is important to understand which mechanisms contribute to impairment of gap junctional communication. Here, we present an update on the known modulators of connexins, including various interaction partners, kinases, and signaling cascades. This gap junction network (GJN) can serve as a blueprint for data mining approaches exploring the growing number of publicly available data sets from experimental and clinical studies.
Collapse
Affiliation(s)
- Stefan Kurtenbach
- Department of Psychology, Faculty of Health, York University Toronto, ON, Canada
| | - Sarah Kurtenbach
- Department of Psychology, Faculty of Health, York University Toronto, ON, Canada
| | - Georg Zoidl
- Department of Psychology, Faculty of Health, York University Toronto, ON, Canada ; Department of Biology, Faculty of Science, York University Toronto, ON, Canada ; Center for Vision Research, York University Toronto, ON, Canada
| |
Collapse
|
15
|
Baker MW, Macagno ER. Control of neuronal morphology and connectivity: Emerging developmental roles for gap junctional proteins. FEBS Lett 2014; 588:1470-9. [DOI: 10.1016/j.febslet.2014.02.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 02/10/2014] [Accepted: 02/12/2014] [Indexed: 11/25/2022]
|
16
|
Nielsen MS, Axelsen LN, Sorgen PL, Verma V, Delmar M, Holstein-Rathlou NH. Gap junctions. Compr Physiol 2013; 2:1981-2035. [PMID: 23723031 DOI: 10.1002/cphy.c110051] [Citation(s) in RCA: 298] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Gap junctions are essential to the function of multicellular animals, which require a high degree of coordination between cells. In vertebrates, gap junctions comprise connexins and currently 21 connexins are known in humans. The functions of gap junctions are highly diverse and include exchange of metabolites and electrical signals between cells, as well as functions, which are apparently unrelated to intercellular communication. Given the diversity of gap junction physiology, regulation of gap junction activity is complex. The structure of the various connexins is known to some extent; and structural rearrangements and intramolecular interactions are important for regulation of channel function. Intercellular coupling is further regulated by the number and activity of channels present in gap junctional plaques. The number of connexins in cell-cell channels is regulated by controlling transcription, translation, trafficking, and degradation; and all of these processes are under strict control. Once in the membrane, channel activity is determined by the conductive properties of the connexin involved, which can be regulated by voltage and chemical gating, as well as a large number of posttranslational modifications. The aim of the present article is to review our current knowledge on the structure, regulation, function, and pharmacology of gap junctions. This will be supported by examples of how different connexins and their regulation act in concert to achieve appropriate physiological control, and how disturbances of connexin function can lead to disease.
Collapse
Affiliation(s)
- Morten Schak Nielsen
- Department of Biomedical Sciences and The Danish National Research Foundation Centre for Cardiac Arrhythmia, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | | | | | | | | |
Collapse
|
17
|
Söhl G, Hombach S, Degen J, Odermatt B. The oligodendroglial precursor cell line Oli-neu represents a cell culture system to examine functional expression of the mouse gap junction gene connexin29 (Cx29). Front Pharmacol 2013; 4:83. [PMID: 23825458 PMCID: PMC3695394 DOI: 10.3389/fphar.2013.00083] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 06/10/2013] [Indexed: 11/13/2022] Open
Abstract
The potential gap junction forming mouse connexin29 (Cx29) protein is concomitantly expressed with connexin32 (Cx32) in peripheral myelin forming Schwann cells and together with both Cx32 and connexin47 (Cx47) in oligodendrocytes of the CNS. To study the genomic structure and functional expression of Cx29, either primary cells or cell culture systems might be selected, from which the latter are easier to cultivate. Both structure and expression of Cx29 is still not fully understood. In the mouse sciatic nerve, brain and the oligodendroglial precursor cell line Oli-neu the Cx29 gene is processed in two transcript isoforms both harboring a unique reading frame. In contrast to Cx32 and Cx47, only Cx29 protein is abundantly expressed in undifferentiated as well as differentiated Oli-neu cells but the absence of Etbr dye transfer after microinjection concealed the function of Cx29-mediated gap junction communication between those cells. Although HeLa cells stably transfected with Cx29 or Cx29-eGFP neither demonstrated any permeability for Lucifer yellow nor for neurobiotin, blocking of Etbr uptake from the media by gap junction blockers does suppose a role of Cx29 in hemi-channel function. Thus, we conclude that, due to its high abundance of Cx29 expression and its reproducible culture conditions, the oligodendroglial precursor cell line Oli-neu might constitute an appropriate cell culture system to study molecular mechanisms or putative extracellular stimuli to functionally open Cx29 channels or hemi-channels.
Collapse
Affiliation(s)
- Goran Söhl
- Abteilung Molekulargenetik, Institut für Genetik, Universität Bonn Bonn, Germany
| | | | | | | |
Collapse
|
18
|
Abstract
Astrocytes are the predominant glial cell population in the central nervous system (CNS). Once considered only passive scaffolding elements, astrocytes are now recognised as cells playing essential roles in CNS development and function. They control extracellular water and ion homeostasis, provide substrates for energy metabolism, and regulate neurogenesis, myelination and synaptic transmission. Due to these multiple activities astrocytes have been implicated in almost all brain pathologies, contributing to various aspects of disease initiation, progression and resolution. Evidence is emerging that astrocyte dysfunction can be the direct cause of neurodegeneration, as shown in Alexander's disease where myelin degeneration is caused by mutations in the gene encoding the astrocyte-specific cytoskeleton protein glial fibrillary acidic protein. Recent studies point to a primary role for astrocytes in the pathogenesis of other genetic leukodystrophies such as megalencephalic leukoencephalopathy with subcortical cysts and vanishing white matter disease. The aim of this review is to summarize current knowledge of the pathophysiological role of astrocytes focusing on their contribution to the development of the above mentioned leukodystrophies and on new perspectives for the treatment of neurological disorders.
Collapse
|
19
|
Zlomuzica A, Tress O, Binder S, Rovira C, Willecke K, Dere E. Changes in object recognition and anxiety-like behaviour in mice expressing a Cx47 mutation that causes Pelizaeus-Merzbacher-like disease. Dev Neurosci 2012; 34:277-87. [PMID: 22832166 DOI: 10.1159/000339305] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 05/03/2012] [Indexed: 12/27/2022] Open
Abstract
Pelizaeus-Merzbacher-like disease is characterized by impaired psychomotor development, ataxia, progressive spasticity and mental retardation. It is induced by mutations in the gap junction gene GJC2 that encodes for the gap junction protein connexin 47. Mice bearing a human Cx47M283T missense mutation have been generated as a transgenic mouse model of Pelizaeus-Merzbacher-like disease. Homozygous expression of the mutant connexin 47 gene in oligodendrocytes resulted in a complex and variable neuropathologic phenotype, which was associated with impairments in motor coordination in juvenile, but not adult mice. In the present study, we have investigated anxiety-like behaviour and spatial working memory in juvenile (P23) and adult (3-month-old) Cx47M282T mutant mice. Adult Cx47M282T mice were also evaluated in terms of neuromotor functions and in the novel object recognition test. Juvenile Cx47M282T mutant mice exhibited an increase in anxiety-like behaviour in the open field test, but no changes in spatial working memory performance. No significant changes in anxiety-like behaviour, spatial working memory or neuromotor functions were observed in the adult Cx47M282T mutant mice. However, novel object recognition was significantly impaired in adult Cx47M282T mice. Our results suggest that the expression of the human Cx47M282T mutation in the mouse causes changes in anxiety-like behaviour in juvenile and novel object recognition impairments in adult mice. It appears that the distortion of panglial gap junction coupling in white and grey matter tissue in the Cx47M282T mice is associated with a complex age-dependent behavioural phenotype including changes in psychomotor, emotional and memory functions.
Collapse
Affiliation(s)
- Armin Zlomuzica
- Institute of Experimental Psychology, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany.
| | | | | | | | | | | |
Collapse
|
20
|
Stys PK. The axo-myelinic synapse. Trends Neurosci 2011; 34:393-400. [PMID: 21741098 DOI: 10.1016/j.tins.2011.06.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 06/01/2011] [Accepted: 06/04/2011] [Indexed: 01/19/2023]
Abstract
Axons have evolved to acquire myelination, enabling denser packing and speedier transmission. Although myelin is considered a passive insulator, recent reports suggest a more dynamic role. Axons, in turn, are endowed with neurotransmitter release and uptake systems along their trunks. Based on these observations, I argue that there may exist a new type of chemical synapse between axon and myelin, one that supports activity-dependent communication between the two. This raises intriguing possibilities of dynamic fine-tuning of the myelin sheath even in adulthood, efficient recruitment of resources for myelin maintenance and bi-directional signaling, whereby the axon informs its myelinating cell of its metabolic needs proportionally to the electrical traffic it is transmitting. This would also have implications for de- and dysmyelinating diseases should this axo-myelinic synapse become dysfunctional.
Collapse
Affiliation(s)
- Peter K Stys
- Department of Clinical Neurosciences, Hotchkiss Brain Institute, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada.
| |
Collapse
|