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Filippov MA, Tatarnikova OG, Pozdnyakova NV, Vorobyov VV. Inflammation/bioenergetics-associated neurodegenerative pathologies and concomitant diseases: a role of mitochondria targeted catalase and xanthophylls. Neural Regen Res 2021; 16:223-233. [PMID: 32859768 PMCID: PMC7896239 DOI: 10.4103/1673-5374.290878] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 02/23/2020] [Accepted: 03/23/2020] [Indexed: 02/07/2023] Open
Abstract
Various inflammatory stimuli are able to modify or even "re-program" the mitochondrial metabolism that results in generation of reactive oxygen species. In noncommunicable chronic diseases such as atherosclerosis and other cardiovascular pathologies, type 2 diabetes and metabolic syndrome, these modifications become systemic and are characterized by chronic inflammation and, in particular, "neuroinflammation" in the central nervous system. The processes associated with chronic inflammation are frequently grouped into "vicious circles" which are able to stimulate each other constantly amplifying the pathological events. These circles are evidently observed in Alzheimer's disease, atherosclerosis, type 2 diabetes, metabolic syndrome and, possibly, other associated pathologies. Furthermore, chronic inflammation in peripheral tissues is frequently concomitant to Alzheimer's disease. This is supposedly associated with some common genetic polymorphisms, for example, Apolipoprotein-E ε4 allele carriers with Alzheimer's disease can also develop atherosclerosis. Notably, in the transgenic mice expressing the recombinant mitochondria targeted catalase, that removes hydrogen peroxide from mitochondria, demonstrates the significant pathology amelioration and health improvements. In addition, the beneficial effects of some natural products from the xanthophyll family, astaxanthin and fucoxanthin, which are able to target the reactive oxygen species at cellular or mitochondrial membranes, have been demonstrated in both animal and human studies. We propose that the normalization of mitochondrial functions could play a key role in the treatment of neurodegenerative disorders and other noncommunicable diseases associated with chronic inflammation in ageing. Furthermore, some prospective drugs based on mitochondria targeted catalase or xanthophylls could be used as an effective treatment of these pathologies, especially at early stages of their development.
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Affiliation(s)
| | | | | | - Vasily V. Vorobyov
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Russia
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Affiliation(s)
| | - Vasily V Vorobyov
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, Russia
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Soleman S, Filippov MA, Dityatev A, Fawcett JW. Targeting the neural extracellular matrix in neurological disorders. Neuroscience 2013; 253:194-213. [PMID: 24012743 DOI: 10.1016/j.neuroscience.2013.08.050] [Citation(s) in RCA: 167] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 08/06/2013] [Accepted: 08/26/2013] [Indexed: 01/15/2023]
Abstract
The extracellular matrix (ECM) is known to regulate important processes in neuronal cell development, activity and growth. It is associated with the structural stabilization of neuronal processes and synaptic contacts during the maturation of the central nervous system. The remodeling of the ECM during both development and after central nervous system injury has been shown to affect neuronal guidance, synaptic plasticity and their regenerative responses. Particular interest has focused on the inhibitory role of chondroitin sulfate proteoglycans (CSPGs) and their formation into dense lattice-like structures, termed perineuronal nets (PNNs), which enwrap sub-populations of neurons and restrict plasticity. Recent studies in mammalian systems have implicated CSPGs and PNNs in regulating and restricting structural plasticity. The enzymatic degradation of CSPGs or destabilization of PNNs has been shown to enhance neuronal activity and plasticity after central nervous system injury. This review focuses on the role of the ECM, CSPGs and PNNs; and how developmental and pharmacological manipulation of these structures have enhanced neuronal plasticity and aided functional recovery in regeneration, stroke, and amblyopia. In addition to CSPGs, this review also points to the functions and potential therapeutic value of these and several other key ECM molecules in epileptogenesis and dementia.
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Affiliation(s)
- S Soleman
- Cambridge Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
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Hanley PJ, Kronlage M, Kirschning C, Del Rey A, Di Virgilio F, Leipziger J, Chessell IP, Sargin S, Filippov MA, Lindemann O, Mohr S, Königs V, Schillers H, Bähler M, Schwab A. Transient P2X7 receptor activation triggers macrophage death independent of Toll-like receptors 2 and 4, caspase-1, and pannexin-1 proteins. J Biol Chem 2012; 287:10650-10663. [PMID: 22235111 DOI: 10.1074/jbc.m111.332676] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The function of P2X(7) receptors (ATP-gated ion channels) in innate immune cells is unclear. In the setting of Toll-like receptor (TLR) stimulation, secondary activation of P2X(7) ion channels has been linked to pro-caspase-1 cleavage and cell death. Here we show that cell death is a surprisingly early triggered event. We show using live-cell imaging that transient (1-4 min) stimulation of mouse macrophages with high extracellular ATP ([ATP]e) triggers delayed (hours) cell death, indexed as DEVDase (caspase-3 and caspase-7) activity. Continuous or transient high [ATP]e did not induce cell death in P2X(7)-deficient (P2X(7)(-/-)) macrophages or neutrophils (in which P2X(7) could not be detected). Blocking sustained Ca(2+) influx, a signature of P2X(7) ligation, was highly protective, whereas no protection was conferred in macrophages lacking caspase-1 or TLR2 and TLR4. Furthermore, pannexin-1 (Panx1) deficiency had no effect on transient ATP-induced delayed cell death or ATP-induced Yo-Pro-1 uptake (an index of large pore pathway formation). Thus, "transient" P2X(7) receptor activation and Ca(2+) overload act as a death trigger for native mouse macrophages independent of Panx1 and pro-inflammatory caspase-1 and TLR signaling.
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Affiliation(s)
- Peter J Hanley
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany,.
| | - Moritz Kronlage
- Institut für Physiologie II, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Carsten Kirschning
- Institut für Medizinische Mikrobiologie, Universität Duisburg-Essen, 45147 Essen, Germany
| | - Adriana Del Rey
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, 35037 Marburg, Germany
| | - Francesco Di Virgilio
- Department of Experimental and Diagnostic Medicine, University of Ferrara, 44100 Ferrara, Italy
| | - Jens Leipziger
- Institute of Physiology and Biophysics, Aarhus University, DK-8000 Aarhus, Denmark
| | - Iain P Chessell
- Neuroscience Centre of Excellence, MedImmune, Cambridge CB21 6GH, United Kingdom, and
| | - Sarah Sargin
- Institut für Physiologie II, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Mikhail A Filippov
- Klinische Neurobiologie, Neurologische Klinik, Universitätsklinikum Heidelberg, 69120 Heidelberg, Germany
| | - Otto Lindemann
- Institut für Physiologie II, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Simon Mohr
- Institut für Physiologie II, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Volker Königs
- Institut für Physiologie II, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Hermann Schillers
- Institut für Physiologie II, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Martin Bähler
- Institut für Molekulare Zellbiologie, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
| | - Albrecht Schwab
- Institut für Physiologie II, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany
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Aydin D, Filippov MA, Tschäpe JA, Gretz N, Prinz M, Eils R, Brors B, Müller UC. Comparative transcriptome profiling of amyloid precursor protein family members in the adult cortex. BMC Genomics 2011; 12:160. [PMID: 21435241 PMCID: PMC3080314 DOI: 10.1186/1471-2164-12-160] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Accepted: 03/24/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The β-amyloid precursor protein (APP) and the related β-amyloid precursor-like proteins (APLPs) undergo complex proteolytic processing giving rise to several fragments. Whereas it is well established that Aβ accumulation is a central trigger for Alzheimer's disease, the physiological role of APP family members and their diverse proteolytic products is still largely unknown. The secreted APPsα ectodomain has been shown to be involved in neuroprotection and synaptic plasticity. The γ-secretase-generated APP intracellular domain (AICD) functions as a transcriptional regulator in heterologous reporter assays although its role for endogenous gene regulation has remained controversial. RESULTS To gain further insight into the molecular changes associated with knockout phenotypes and to elucidate the physiological functions of APP family members including their proposed role as transcriptional regulators, we performed DNA microarray transcriptome profiling of prefrontal cortex of adult wild-type (WT), APP knockout (APP-/-), APLP2 knockout (APLP2-/-) and APPsα knockin mice (APPα/α) expressing solely the secreted APPsα ectodomain. Biological pathways affected by the lack of APP family members included neurogenesis, transcription, and kinase activity. Comparative analysis of transcriptome changes between mutant and wild-type mice, followed by qPCR validation, identified co-regulated gene sets. Interestingly, these included heat shock proteins and plasticity-related genes that were both down-regulated in knockout cortices. In contrast, we failed to detect significant differences in expression of previously proposed AICD target genes including Bace1, Kai1, Gsk3b, p53, Tip60, and Vglut2. Only Egfr was slightly up-regulated in APLP2-/- mice. Comparison of APP-/- and APPα/α with wild-type mice revealed a high proportion of co-regulated genes indicating an important role of the C-terminus for cellular signaling. Finally, comparison of APLP2-/- on different genetic backgrounds revealed that background-related transcriptome changes may dominate over changes due to the knockout of a single gene. CONCLUSION Shared transcriptome profiles corroborated closely related physiological functions of APP family members in the adult central nervous system. As expression of proposed AICD target genes was not altered in adult cortex, this may indicate that these genes are not affected by lack of APP under resting conditions or only in a small subset of cells.
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Affiliation(s)
- Dorothee Aydin
- Department of Bioinformatics and Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Im Neuenheimer Feld 364, D-69120 Heidelberg, Germany
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Abstract
Proteolytical cleavage of the beta-amyloid precursor protein (APP) generates beta-amyloid, which is deposited in the brains of patients suffering from Alzheimer's disease (AD). Despite the well-established key role of APP for AD pathogenesis, the physiological function of APP and its close homologues APLP1 and APLP2 remains poorly understood. Previously, we generated APP(-/-) mice that proved viable, whereas APP(-/-)APLP2(-/-) mice and triple knockouts died shortly after birth, likely due to deficits of neuromuscular synaptic transmission. Here, we generated conditional knockout alleles for both APP and APLP2 in which the promoter and exon1 were flanked by loxP sites. No differences in expression were detectable between wt and floxed alleles, whereas null alleles were obtained upon crossing with Cre-transgenic deleter mice. These mice will now allow for tissue and time-point controlled knockout of both genes.
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Affiliation(s)
- Jan-Philipp Mallm
- Department of Bioinformatics and Functional Genomics, Institute of Pharmacy and Molecular Biotechnology, University of Heidelberg, Heidelberg, Germany
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Anselmi F, Hernandez VH, Crispino G, Seydel A, Ortolano S, Roper SD, Kessaris N, Richardson W, Rickheit G, Filippov MA, Monyer H, Mammano F. ATP release through connexin hemichannels and gap junction transfer of second messengers propagate Ca2+ signals across the inner ear. Proc Natl Acad Sci U S A 2008; 105:18770-5. [PMID: 19047635 PMCID: PMC2596208 DOI: 10.1073/pnas.0800793105] [Citation(s) in RCA: 262] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2008] [Indexed: 11/18/2022] Open
Abstract
Extracellular ATP controls various signaling systems including propagation of intercellular Ca(2+) signals (ICS). Connexin hemichannels, P2x7 receptors (P2x7Rs), pannexin channels, anion channels, vesicles, and transporters are putative conduits for ATP release, but their involvement in ICS remains controversial. We investigated ICS in cochlear organotypic cultures, in which ATP acts as an IP(3)-generating agonist and evokes Ca(2+) responses that have been linked to noise-induced hearing loss and development of hair cell-afferent synapses. Focal delivery of ATP or photostimulation with caged IP(3) elicited Ca(2+) responses that spread radially to several orders of unstimulated cells. Furthermore, we recorded robust Ca(2+) signals from an ATP biosensor apposed to supporting cells outside the photostimulated area in WT cultures. ICS propagated normally in cultures lacking either P2x7R or pannexin-1 (Px1), as well as in WT cultures exposed to blockers of anion channels. By contrast, Ca(2+) responses failed to propagate in cultures with defective expression of connexin 26 (Cx26) or Cx30. A companion paper demonstrates that, if expression of either Cx26 or Cx30 is blocked, expression of the other is markedly down-regulated in the outer sulcus. Lanthanum, a connexin hemichannel blocker that does not affect gap junction (GJ) channels when applied extracellularly, limited the propagation of Ca(2+) responses to cells adjacent to the photostimulated area. Our results demonstrate that these connexins play a dual crucial role in inner ear Ca(2+) signaling: as hemichannels, they promote ATP release, sustaining long-range ICS propagation; as GJ channels, they allow diffusion of Ca(2+)-mobilizing second messengers across coupled cells.
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Affiliation(s)
- Fabio Anselmi
- Foundation for Advanced Biomedical Research, Venetian Institute of Molecular Medicine, 35129 Padua, Italy
| | - Victor H. Hernandez
- Foundation for Advanced Biomedical Research, Venetian Institute of Molecular Medicine, 35129 Padua, Italy
| | - Giulia Crispino
- Foundation for Advanced Biomedical Research, Venetian Institute of Molecular Medicine, 35129 Padua, Italy
| | - Anke Seydel
- Foundation for Advanced Biomedical Research, Venetian Institute of Molecular Medicine, 35129 Padua, Italy
| | - Saida Ortolano
- Foundation for Advanced Biomedical Research, Venetian Institute of Molecular Medicine, 35129 Padua, Italy
- Department of Physics “G. Galilei,” University of Padua, 35129 Padua, Italy
| | - Stephen D. Roper
- Department of Physiology and Biophysics and Program in Neurosciences, Miller School of Medicine, University of Miami, Miami, FL 33136
| | - Nicoletta Kessaris
- Wolfson Institute for Biomedical Research and Department of Biology, University College London, London WC1E 6BT, United Kingdom
| | - William Richardson
- Wolfson Institute for Biomedical Research and Department of Biology, University College London, London WC1E 6BT, United Kingdom
| | - Gesa Rickheit
- Leibniz-Institut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), D-13125 Berlin, Germany; and
| | - Mikhail A. Filippov
- Department of Clinical Neurobiology, University Hospital of Neurology, Heidelberg, Germany
| | - Hannah Monyer
- Department of Clinical Neurobiology, University Hospital of Neurology, Heidelberg, Germany
| | - Fabio Mammano
- Foundation for Advanced Biomedical Research, Venetian Institute of Molecular Medicine, 35129 Padua, Italy
- Department of Physics “G. Galilei,” University of Padua, 35129 Padua, Italy
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Ring S, Weyer SW, Kilian SB, Waldron E, Pietrzik CU, Filippov MA, Herms J, Buchholz C, Eckman CB, Korte M, Wolfer DP, Müller UC. The secreted beta-amyloid precursor protein ectodomain APPs alpha is sufficient to rescue the anatomical, behavioral, and electrophysiological abnormalities of APP-deficient mice. J Neurosci 2007; 27:7817-26. [PMID: 17634375 PMCID: PMC6672885 DOI: 10.1523/jneurosci.1026-07.2007] [Citation(s) in RCA: 298] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
It is well established that the proteolytic processing of the beta-amyloid precursor protein (APP) generates beta-amyloid (Abeta), which plays a central role in the pathogenesis of Alzheimer's disease (AD). In contrast, the physiological role of APP and of its numerous proteolytic fragments and the question of whether a loss of these functions contributes to AD are still unknown. To address this question, we replaced the endogenous APP locus by gene-targeted alleles and generated two lines of knock-in mice that exclusively express APP deletion variants corresponding either to the secreted APP ectodomain (APPs alpha) or to a C-terminal (CT) truncation lacking the YENPTY interaction motif (APPdeltaCT15). Interestingly, the deltaCT15 deletion resulted in reduced turnover of holoAPP, increased cell surface expression, and strongly reduced Abeta levels in brain, likely because of reduced processing in the endocytic pathway. Most importantly, we demonstrate that in both APP knock-in lines the expression of APP N-terminal domains either grossly attenuated or completely rescued the prominent deficits of APP knock-out mice, such as reductions in brain and body weight, grip strength deficits, alterations in circadian locomotor activity, exploratory activity, and the impairment in spatial learning and long-term potentiation. Together, our data suggest that the APP C terminus is dispensable and that APPs alpha is sufficient to mediate the physiological functions of APP assessed by these tests.
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Affiliation(s)
- Sabine Ring
- Department of Bioinformatics and Functional Genomics, Institute for Pharmacy and Molecular Biotechnology, University of Heidelberg, D-69120 Heidelberg, Germany
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Hébert SS, Serneels L, Tolia A, Craessaerts K, Derks C, Filippov MA, Müller U, De Strooper B. Regulated intramembrane proteolysis of amyloid precursor protein and regulation of expression of putative target genes. EMBO Rep 2006; 7:739-45. [PMID: 16729020 PMCID: PMC1500829 DOI: 10.1038/sj.embor.7400704] [Citation(s) in RCA: 156] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2006] [Revised: 04/11/2006] [Accepted: 04/12/2006] [Indexed: 11/09/2022] Open
Abstract
gamma-Secretase-dependent regulated intramembrane proteolysis of amyloid precursor protein (APP) releases the APP intracellular domain (AICD). The question of whether this domain, like the Notch intracellular domain, is involved in nuclear signalling is highly controversial. Although some reports suggest that AICD regulates the expression of KAI1, glycogen synthase kinase-3beta, Neprilysin and APP, we found no consistent effects of gamma-secretase inhibitors or of genetic deficiencies in the gamma-secretase complex or the APP family on the expression levels of these genes in cells and tissues. Finally, we demonstrate that Fe65, an important AICD-binding protein, transactivates a wide variety of different promoters, including the viral simian virus 40 promoter, independent of AICD coexpression. Overall, the four currently proposed target genes are at best indirectly and weakly influenced by APP processing. Therefore, inhibition of APP processing to decrease Abeta generation in Alzheimer's disease will not interfere significantly with the function of these genes.
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Affiliation(s)
- Sébastien S Hébert
- Neuronal Cell Biology and Gene Transfer, CME, Flanders Interuniversity Institute for Biotechnology (VIB4) and Katholieke Universiteit Leuven, Herestraat 49, Leuven 3000, Belgium
| | - Lutgarde Serneels
- Neuronal Cell Biology and Gene Transfer, CME, Flanders Interuniversity Institute for Biotechnology (VIB4) and Katholieke Universiteit Leuven, Herestraat 49, Leuven 3000, Belgium
| | - Alexandra Tolia
- Neuronal Cell Biology and Gene Transfer, CME, Flanders Interuniversity Institute for Biotechnology (VIB4) and Katholieke Universiteit Leuven, Herestraat 49, Leuven 3000, Belgium
| | - Katleen Craessaerts
- Neuronal Cell Biology and Gene Transfer, CME, Flanders Interuniversity Institute for Biotechnology (VIB4) and Katholieke Universiteit Leuven, Herestraat 49, Leuven 3000, Belgium
| | - Carmen Derks
- Neuronal Cell Biology and Gene Transfer, CME, Flanders Interuniversity Institute for Biotechnology (VIB4) and Katholieke Universiteit Leuven, Herestraat 49, Leuven 3000, Belgium
| | - Mikhail A Filippov
- Max-Planck Institute for Brain Research, Deutschordenstrasse 46, 60598 Frankfurt, Germany
- Institute for Pharmacy and Molecular Biotechnology, University of Heidelberg, Im Neuenheimer Feld 364, 69120 Heidelberg, Germany
| | - Ulrike Müller
- Max-Planck Institute for Brain Research, Deutschordenstrasse 46, 60598 Frankfurt, Germany
- Institute for Pharmacy and Molecular Biotechnology, University of Heidelberg, Im Neuenheimer Feld 364, 69120 Heidelberg, Germany
| | - Bart De Strooper
- Neuronal Cell Biology and Gene Transfer, CME, Flanders Interuniversity Institute for Biotechnology (VIB4) and Katholieke Universiteit Leuven, Herestraat 49, Leuven 3000, Belgium
- Tel: +32 163 46227; Fax: +32 163 47181; E-mail:
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Hormuzdi SG, Filippov MA, Mitropoulou G, Monyer H, Bruzzone R. Electrical synapses: a dynamic signaling system that shapes the activity of neuronal networks. Biochim Biophys Acta 2004; 1662:113-37. [PMID: 15033583 DOI: 10.1016/j.bbamem.2003.10.023] [Citation(s) in RCA: 154] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2003] [Revised: 10/14/2003] [Accepted: 10/14/2003] [Indexed: 01/25/2023]
Abstract
Gap junctions consist of intercellular channels dedicated to providing a direct pathway for ionic and biochemical communication between contacting cells. After an initial burst of publications describing electrical coupling in the brain, gap junctions progressively became less fashionable among neurobiologists, as the consensus was that this form of synaptic transmission would play a minimal role in shaping neuronal activity in higher vertebrates. Several new findings over the last decade (e.g. the implication of connexins in genetic diseases of the nervous system, in processing sensory information and in synchronizing the activity of neuronal networks) have brought gap junctions back into the spotlight. The appearance of gap junctional coupling in the nervous system is developmentally regulated, restricted to distinct cell types and persists after the establishment of chemical synapses, thus suggesting that this form of cell-cell signaling may be functionally interrelated with, rather than alternative to chemical transmission. This review focuses on gap junctions between neurons and summarizes the available data, derived from molecular, biological, electrophysiological, and genetic approaches, that are contributing to a new appreciation of their role in brain function.
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Affiliation(s)
- Sheriar G Hormuzdi
- Department of Clinical Neurobiology, Interdisciplinary Center for Neurosciences, University of Heidelberg, 69120 Heidelberg, Germany
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Abstract
A variety of connexins are expressed in the diverse cell types of the central nervous system and are thought to regulate some of the functional properties exhibited by immature and mature cells. A proper understanding of the role of specific connexins in these processes requires an unambiguous characterization of their spatial and temporal pattern of expression. In order to define the cellular distribution of connexin 26 (Cx26) in the mouse we have generated a reporter allele (Cx26lacZ) by genetically manipulating the locus so that the beta-galactosidase (lacZ) gene is expressed from the endogenous Cx26 promoter. This modification decreased expression from the allele and resulted in embryonic lethality for the Cx26lacZ/lacZ genotype in accordance with previous studies on Cx26 knock-out animals indicating that Cx26-containing gap junctions are necessary for embryonic development. Despite the lower than expected transcript levels, the amount of lacZ protein produced in heterozygous mice was sufficient to label tissues known to contain Cx26, such as liver, kidney, skin, cochlea, small intestine, placenta and thyroid gland. In the embryonic and mature central nervous system, however, lacZ was restricted to meningeal cells and could not be detected in either neurons or glia. The absence of Cx26 mRNA in these cells could also be confirmed by reverse transcription-polymerase chain reaction and in situ hybridization. Our experiments indicate that the Cx26lacZ mouse line can be used as a reporter of Cx26 gene expression and suggest that Cx26, contrary to previous reports, is restricted to the meninges in both embryonic and adult brain.
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Affiliation(s)
- Mikhail A Filippov
- Department of Clinical Neurobiology, University Hospital of Neurology, Im Neuenheimer Feld 364, 69120 Heidelberg, Germany
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Bogolepov NK, Dubrovskaia MK, Filippov MA. [Disorders of motor functions in patients with apoplectic coma]. Vrach Delo 1977:88-94. [PMID: 878431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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