1
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Liu Z, Pan C, Huang H. The role of axon guidance molecules in the pathogenesis of epilepsy. Neural Regen Res 2025; 20:1244-1257. [PMID: 39075893 DOI: 10.4103/nrr.nrr-d-23-01620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 02/21/2024] [Indexed: 07/31/2024] Open
Abstract
Current treatments for epilepsy can only manage the symptoms of the condition but cannot alter the initial onset or halt the progression of the disease. Consequently, it is crucial to identify drugs that can target novel cellular and molecular mechanisms and mechanisms of action. Increasing evidence suggests that axon guidance molecules play a role in the structural and functional modifications of neural networks and that the dysregulation of these molecules is associated with epilepsy susceptibility. In this review, we discuss the essential role of axon guidance molecules in neuronal activity in patients with epilepsy as well as the impact of these molecules on synaptic plasticity and brain tissue remodeling. Furthermore, we examine the relationship between axon guidance molecules and neuroinflammation, as well as the structural changes in specific brain regions that contribute to the development of epilepsy. Ample evidence indicates that axon guidance molecules, including semaphorins and ephrins, play a fundamental role in guiding axon growth and the establishment of synaptic connections. Deviations in their expression or function can disrupt neuronal connections, ultimately leading to epileptic seizures. The remodeling of neural networks is a significant characteristic of epilepsy, with axon guidance molecules playing a role in the dynamic reorganization of neural circuits. This, in turn, affects synapse formation and elimination. Dysregulation of these molecules can upset the delicate balance between excitation and inhibition within a neural network, thereby increasing the risk of overexcitation and the development of epilepsy. Inflammatory signals can regulate the expression and function of axon guidance molecules, thus influencing axonal growth, axon orientation, and synaptic plasticity. The dysregulation of neuroinflammation can intensify neuronal dysfunction and contribute to the occurrence of epilepsy. This review delves into the mechanisms associated with the pathogenicity of axon guidance molecules in epilepsy, offering a valuable reference for the exploration of therapeutic targets and presenting a fresh perspective on treatment strategies for this condition.
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Affiliation(s)
- Zheng Liu
- Department of Neurology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou Province, China
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2
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Chatzikalil E, Stergiou IE, Papadakos SP, Konstantinidis I, Theocharis S. The Clinical Relevance of the EPH/Ephrin Signaling Pathway in Pediatric Solid and Hematologic Malignancies. Int J Mol Sci 2024; 25:3834. [PMID: 38612645 PMCID: PMC11011407 DOI: 10.3390/ijms25073834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 03/26/2024] [Accepted: 03/26/2024] [Indexed: 04/14/2024] Open
Abstract
Pediatric neoplasms represent a complex group of malignancies that pose unique challenges in terms of diagnosis, treatment, and understanding of the underlying molecular pathogenetic mechanisms. Erythropoietin-producing hepatocellular receptors (EPHs), the largest family of receptor tyrosine kinases and their membrane-tethered ligands, ephrins, orchestrate short-distance cell-cell signaling and are intricately involved in cell-pattern morphogenesis and various developmental processes. Unraveling the role of the EPH/ephrin signaling pathway in the pathophysiology of pediatric neoplasms and its clinical implications can contribute to deciphering the intricate landscape of these malignancies. The bidirectional nature of the EPH/ephrin axis is underscored by emerging evidence revealing its capacity to drive tumorigenesis, fostering cell-cell communication within the tumor microenvironment. In the context of carcinogenesis, the EPH/ephrin signaling pathway prompts a reevaluation of treatment strategies, particularly in pediatric oncology, where the modest progress in survival rates and enduring treatment toxicity necessitate novel approaches. Molecularly targeted agents have emerged as promising alternatives, prompting a shift in focus. Through a nuanced understanding of the pathway's intricacies, we aim to lay the groundwork for personalized diagnostic and therapeutic strategies, ultimately contributing to improved outcomes for young patients grappling with neoplastic challenges.
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Affiliation(s)
- Elena Chatzikalil
- Division of Pediatric Hematology-Oncology, First Department of Pediatrics, School of Medicine, National and Kapodistrian University of Athens, 11527 Athens, Greece;
| | - Ioanna E. Stergiou
- Department of Pathophysiology, School of Medicine, National and Kapodistrian University of Athens, 11527 Athens, Greece;
| | - Stavros P. Papadakos
- First Department of Pathology, School of Medicine, National and Kapodistrian University of Athens, 11527 Athens, Greece;
| | | | - Stamatios Theocharis
- First Department of Pathology, School of Medicine, National and Kapodistrian University of Athens, 11527 Athens, Greece;
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3
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Assali A, Chenaux G, Cho JY, Berto S, Ehrlich NA, Cowan CW. EphB1 controls long-range cortical axon guidance through a cell non-autonomous role in GABAergic cells. Development 2024; 151:dev201439. [PMID: 38345254 PMCID: PMC10946438 DOI: 10.1242/dev.201439] [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: 11/15/2022] [Accepted: 01/28/2024] [Indexed: 02/29/2024]
Abstract
EphB1 is required for proper guidance of cortical axon projections during brain development, but how EphB1 regulates this process remains unclear. We show here that EphB1 conditional knockout (cKO) in GABAergic cells (Vgat-Cre), but not in cortical excitatory neurons (Emx1-Cre), reproduced the cortical axon guidance defects observed in global EphB1 KO mice. Interestingly, in EphB1 cKOVgat mice, the misguided axon bundles contained co-mingled striatal GABAergic and somatosensory cortical glutamatergic axons. In wild-type mice, somatosensory axons also co-fasciculated with striatal axons, notably in the globus pallidus, suggesting that a subset of glutamatergic cortical axons normally follows long-range GABAergic axons to reach their targets. Surprisingly, the ectopic axons in EphB1 KO mice were juxtaposed to major blood vessels. However, conditional loss of EphB1 in endothelial cells (Tie2-Cre) did not produce the axon guidance defects, suggesting that EphB1 in GABAergic neurons normally promotes avoidance of these ectopic axons from the developing brain vasculature. Together, our data reveal a new role for EphB1 in GABAergic neurons to influence proper cortical glutamatergic axon guidance during brain development.
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Affiliation(s)
- Ahlem Assali
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29425, USA
| | - George Chenaux
- Department of Psychiatry, University of Texas Southwestern Medical School, Dallas, TX 75390, USA
| | - Jennifer Y. Cho
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Stefano Berto
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Nathan A. Ehrlich
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Christopher W. Cowan
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC 29425, USA
- Department of Psychiatry, University of Texas Southwestern Medical School, Dallas, TX 75390, USA
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4
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Yildiz CB, Kundu T, Gehrmann J, Koesling J, Ravaei A, Wolff P, Kraft F, Maié T, Jakovcevski M, Pensold D, Zimmermann O, Rossetti G, Costa IG, Zimmer-Bensch G. EphrinA5 regulates cell motility by modulating Snhg15/DNA triplex-dependent targeting of DNMT1 to the Ncam1 promoter. Epigenetics Chromatin 2023; 16:42. [PMID: 37880732 PMCID: PMC10601256 DOI: 10.1186/s13072-023-00516-4] [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: 05/25/2023] [Accepted: 10/13/2023] [Indexed: 10/27/2023] Open
Abstract
Cell-cell communication is mediated by membrane receptors and their ligands, such as the Eph/ephrin system, orchestrating cell migration during development and in diverse cancer types. Epigenetic mechanisms are key for integrating external "signals", e.g., from neighboring cells, into the transcriptome in health and disease. Previously, we reported ephrinA5 to trigger transcriptional changes of lncRNAs and protein-coding genes in cerebellar granule cells, a cell model for medulloblastoma. LncRNAs represent important adaptors for epigenetic writers through which they regulate gene expression. Here, we investigate a lncRNA-mediated targeting of DNMT1 to specific gene loci by the combined power of in silico modeling of RNA/DNA interactions and wet lab approaches, in the context of the clinically relevant use case of ephrinA5-dependent regulation of cellular motility of cerebellar granule cells. We provide evidence that Snhg15, a cancer-related lncRNA, recruits DNMT1 to the Ncam1 promoter through RNA/DNA triplex structure formation and the interaction with DNMT1. This mediates DNA methylation-dependent silencing of Ncam1, being abolished by ephrinA5 stimulation-triggered reduction of Snhg15 expression. Hence, we here propose a triple helix recognition mechanism, underlying cell motility regulation via lncRNA-targeted DNA methylation in a clinically relevant context.
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Affiliation(s)
- Can Bora Yildiz
- Institute of Zoology (Biology 2), Division of Neuroepigenetics, RWTH Aachen University, Worringerweg 3, 52074, Aachen, Germany
- Research Training Group 2416 Multi Senses - Multi Scales, RWTH Aachen University, 52074, Aachen, Germany
| | - Tathagata Kundu
- Jülich Supercomputing Centre, Forschungszentrum Jülich GmbH, 52425, Jülich, Germany
| | - Julia Gehrmann
- Institute for Computational Genomics, RWTH Aachen University, Medical Faculty, 52074, Aachen, Germany
| | - Jannis Koesling
- Institute of Zoology (Biology 2), Division of Neuroepigenetics, RWTH Aachen University, Worringerweg 3, 52074, Aachen, Germany
| | - Amin Ravaei
- Institute of Zoology (Biology 2), Division of Neuroepigenetics, RWTH Aachen University, Worringerweg 3, 52074, Aachen, Germany
- Department of Neurosciences and Rehabilitation, Section of Medical Biochemistry, Molecular Biology and Genetics, University of Ferrara, Ferrara, Italy
| | - Philip Wolff
- Institute of Zoology (Biology 2), Division of Neuroepigenetics, RWTH Aachen University, Worringerweg 3, 52074, Aachen, Germany
| | - Florian Kraft
- Institute for Human Genetics and Genomic Medicine, Medical Faculty, RWTH Aachen University, 52074, Aachen, Germany
| | - Tiago Maié
- Institute for Computational Genomics, RWTH Aachen University, Medical Faculty, 52074, Aachen, Germany
| | - Mira Jakovcevski
- Institute of Zoology (Biology 2), Division of Neuroepigenetics, RWTH Aachen University, Worringerweg 3, 52074, Aachen, Germany
| | - Daniel Pensold
- Institute of Zoology (Biology 2), Division of Neuroepigenetics, RWTH Aachen University, Worringerweg 3, 52074, Aachen, Germany
| | - Olav Zimmermann
- Jülich Supercomputing Centre, Forschungszentrum Jülich GmbH, 52425, Jülich, Germany
| | - Giulia Rossetti
- Jülich Supercomputing Centre, Forschungszentrum Jülich GmbH, 52425, Jülich, Germany
- Department of Neurology, University Hospital Aachen, RWTH Aachen University, Aachen, Germany
- Institute of Neuroscience and Medicine (INM-9)/Institute of Advanced Simulations (IAS-5), Forschungszentrum Jülich GmbH, 52425, Jülich, Germany
| | - Ivan G Costa
- Institute for Computational Genomics, RWTH Aachen University, Medical Faculty, 52074, Aachen, Germany
| | - Geraldine Zimmer-Bensch
- Institute of Zoology (Biology 2), Division of Neuroepigenetics, RWTH Aachen University, Worringerweg 3, 52074, Aachen, Germany.
- Research Training Group 2416 Multi Senses - Multi Scales, RWTH Aachen University, 52074, Aachen, Germany.
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5
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Yildiz CB, Zimmer-Bensch G. Role of DNMTs in the Brain. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1389:363-394. [DOI: 10.1007/978-3-031-11454-0_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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6
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Reichard J, Zimmer-Bensch G. The Epigenome in Neurodevelopmental Disorders. Front Neurosci 2021; 15:776809. [PMID: 34803599 PMCID: PMC8595945 DOI: 10.3389/fnins.2021.776809] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 10/04/2021] [Indexed: 12/26/2022] Open
Abstract
Neurodevelopmental diseases (NDDs), such as autism spectrum disorders, epilepsy, and schizophrenia, are characterized by diverse facets of neurological and psychiatric symptoms, differing in etiology, onset and severity. Such symptoms include mental delay, cognitive and language impairments, or restrictions to adaptive and social behavior. Nevertheless, all have in common that critical milestones of brain development are disrupted, leading to functional deficits of the central nervous system and clinical manifestation in child- or adulthood. To approach how the different development-associated neuropathologies can occur and which risk factors or critical processes are involved in provoking higher susceptibility for such diseases, a detailed understanding of the mechanisms underlying proper brain formation is required. NDDs rely on deficits in neuronal identity, proportion or function, whereby a defective development of the cerebral cortex, the seat of higher cognitive functions, is implicated in numerous disorders. Such deficits can be provoked by genetic and environmental factors during corticogenesis. Thereby, epigenetic mechanisms can act as an interface between external stimuli and the genome, since they are known to be responsive to external stimuli also in cortical neurons. In line with that, DNA methylation, histone modifications/variants, ATP-dependent chromatin remodeling, as well as regulatory non-coding RNAs regulate diverse aspects of neuronal development, and alterations in epigenomic marks have been associated with NDDs of varying phenotypes. Here, we provide an overview of essential steps of mammalian corticogenesis, and discuss the role of epigenetic mechanisms assumed to contribute to pathophysiological aspects of NDDs, when being disrupted.
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Affiliation(s)
- Julia Reichard
- Functional Epigenetics in the Animal Model, Institute for Biology II, RWTH Aachen University, Aachen, Germany
- Research Training Group 2416 MultiSenses-MultiScales, Institute for Biology II, RWTH Aachen University, Aachen, Germany
| | - Geraldine Zimmer-Bensch
- Functional Epigenetics in the Animal Model, Institute for Biology II, RWTH Aachen University, Aachen, Germany
- Research Training Group 2416 MultiSenses-MultiScales, Institute for Biology II, RWTH Aachen University, Aachen, Germany
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7
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Symmank J, Gölling V, Gerstmann K, Zimmer G. The Transcription Factor LHX1 Regulates the Survival and Directed Migration of POA-derived Cortical Interneurons. Cereb Cortex 2020; 29:1644-1658. [PMID: 29912395 DOI: 10.1093/cercor/bhy063] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Revised: 02/22/2018] [Accepted: 02/23/2018] [Indexed: 12/17/2022] Open
Abstract
The delicate balance of excitation and inhibition is crucial for proper function of the cerebral cortex, relying on the accurate number and subtype composition of inhibitory gamma-aminobutyric (GABA)-expressing interneurons. Various intrinsic and extrinsic factors precisely orchestrate their multifaceted development including the long-range migration from the basal telencephalon to cortical targets as well as interneuron survival throughout the developmental period. Particularly expressed guidance receptors were described to channel the migration of cortical interneurons deriving from the medial ganglionic eminence (MGE) and the preoptic area (POA) along distinct routes. Hence, unveiling the regulatory genetic networks controlling subtype-specific gene expression profiles is key to understand interneuron-specific developmental programs and to reveal causes for associated disorders. In contrast to MGE-derived interneurons, little is known about the transcriptional networks in interneurons born in the POA. Here, we provide first evidence for the LIM-homeobox transcription factor LHX1 as a crucial key player in the post-mitotic development of POA-derived cortical interneurons. By transcriptional regulation of related genes, LHX1 modulates their survival as well as the subtype-specific expression of guidance receptors of the Eph/ephrin family, thereby affecting directional migration and layer distribution in the adult cortex.
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Affiliation(s)
- Judit Symmank
- Institute of Human Genetics, University Hospital Jena, Jena, Germany
| | - Vanessa Gölling
- Institute of Human Genetics, University Hospital Jena, Jena, Germany
| | - Katrin Gerstmann
- Institute of Human Genetics, University Hospital Jena, Jena, Germany
| | - Geraldine Zimmer
- Institute of Human Genetics, University Hospital Jena, Jena, Germany
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8
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Diverse facets of cortical interneuron migration regulation – Implications of neuronal activity and epigenetics. Brain Res 2018; 1700:160-169. [DOI: 10.1016/j.brainres.2018.09.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Revised: 09/02/2018] [Accepted: 09/03/2018] [Indexed: 01/21/2023]
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9
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Talebian A, Britton R, Henkemeyer M. Abnormalities in cortical interneuron subtypes in ephrin-B mutant mice. Eur J Neurosci 2018; 48:1803-1817. [PMID: 29904965 DOI: 10.1111/ejn.14022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Revised: 05/19/2018] [Accepted: 06/04/2018] [Indexed: 12/01/2022]
Abstract
To explore roles for ephrin-B/EphB signaling in cortical interneurons, we previously generated ephrin-B (Efnb1/b2/b3) conditional triple mutant (TMlz ) mice using a Dlx1/2.Cre inhibitory neuron driver and green fluorescent protein (GFP) reporters for the two main inhibitory interneuron groups distinguished by expression of either glutamic acid decarboxylase 1 (GAD1; GAD67-GFP) or 2 (GAD2; GAD65-GFP). This work showed a general involvement of ephrin-B in migration and population of interneurons into the embryonic neocortex. We now determined whether specific interneurons are selectively affected in the adult brains of TMlz .Cre mice by immunostaining with antibodies that identify the different subtypes. The results indicate that GAD67-GFP-expressing interneurons that also express parvalbumin (PV), calretinin (CR) and, to a lesser extent, somatostatin (SST) and Reelin (Rln) were significantly reduced in the cortex and hippocampal CA1 region in TMlz .Cre mutant mice. Neuropeptide Y (NPY) interneurons that also express GAD67-GFP were reduced in the hippocampal CA1 region, but much less so in the cortex, although these cells exhibited abnormal cortical layering. In GAD65-GFP-expressing interneurons, CR subtypes were reduced in both cortex and hippocampal CA1 region, whereas Rln interneurons were reduced exclusively in hippocampus, and the numbers of NPY and vasoactive intestinal polypeptide (VIP) subtypes appeared normal. PV and CR subtype interneurons in TMlz .Cre mice also exhibited reductions in their perisomatic area, suggesting abnormalities in dendritic/axonal complexity. Altogether, our data indicate that ephrin-B expression within forebrain interneurons is required in specific subtypes for their normal population, cortical layering and elaboration of cell processes.
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Affiliation(s)
- Asghar Talebian
- Department of Neuroscience and Kent Waldrep Center for Basic Research on Nerve Growth and Regeneration, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Rachel Britton
- Department of Neuroscience and Kent Waldrep Center for Basic Research on Nerve Growth and Regeneration, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Mark Henkemeyer
- Department of Neuroscience and Kent Waldrep Center for Basic Research on Nerve Growth and Regeneration, University of Texas Southwestern Medical Center, Dallas, Texas
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10
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Talebian A, Britton R, Ammanuel S, Bepari A, Sprouse F, Birnbaum SG, Szabó G, Tamamaki N, Gibson J, Henkemeyer M. Autonomous and non-autonomous roles for ephrin-B in interneuron migration. Dev Biol 2017; 431:179-193. [PMID: 28947178 DOI: 10.1016/j.ydbio.2017.09.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Revised: 09/05/2017] [Accepted: 09/18/2017] [Indexed: 11/28/2022]
Abstract
While several studies indicate the importance of ephrin-B/EphB bidirectional signaling in excitatory neurons, potential roles for these molecules in inhibitory neurons are largely unknown. We identify here an autonomous receptor-like role for ephrin-B reverse signaling in the tangential migration of interneurons into the neocortex using ephrin-B (EfnB1/B2/B3) conditional triple mutant (TMlz) mice and a forebrain inhibitory neuron specific Cre driver. Inhibitory neuron deletion of the three EfnB genes leads to reduced interneuron migration, abnormal cortical excitability, and lethal audiogenic seizures. Truncated and intracellular point mutations confirm the importance of ephrin-B reverse signaling in interneuron migration and cortical excitability. A non-autonomous ligand-like role was also identified for ephrin-B2 that is expressed in neocortical radial glial cells and required for proper tangential migration of GAD65-positive interneurons. Our studies thus define both receptor-like and ligand-like roles for the ephrin-B molecules in controlling the migration of interneurons as they populate the neocortex and help establish excitatory/inhibitory (E/I) homeostasis.
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Affiliation(s)
- Asghar Talebian
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Kent Waldrep Center for Basic Research on Nerve Growth and Regeneration, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Rachel Britton
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Kent Waldrep Center for Basic Research on Nerve Growth and Regeneration, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Simon Ammanuel
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Asim Bepari
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Kent Waldrep Center for Basic Research on Nerve Growth and Regeneration, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Francis Sprouse
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Kent Waldrep Center for Basic Research on Nerve Growth and Regeneration, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Shari G Birnbaum
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Gábor Szabó
- Medical Gene Technology Division, Institute of Experimental Medicine, 1083 Budapest, Hungary
| | - Nobuaki Tamamaki
- Department of Morphological Neural Science, Kumamoto University, Kumamoto 860-8556, Japan
| | - Jay Gibson
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Mark Henkemeyer
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA; Kent Waldrep Center for Basic Research on Nerve Growth and Regeneration, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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11
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Kemmerling N, Wunderlich P, Theil S, Linnartz-Gerlach B, Hersch N, Hoffmann B, Heneka MT, de Strooper B, Neumann H, Walter J. Intramembranous processing by γ-secretase regulates reverse signaling of ephrin-B2 in migration of microglia. Glia 2017; 65:1103-1118. [PMID: 28370426 DOI: 10.1002/glia.23147] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 03/14/2017] [Accepted: 03/16/2017] [Indexed: 12/30/2022]
Abstract
The Eph-ephrin system plays pivotal roles in cell adhesion and migration. The receptor-like functions of the ephrin ligands allow the regulation of intracellular processes via reverse signaling. γ-Secretase mediated processing of ephrin-B has previously been linked to activation of Src, a kinase crucial for focal adhesion and podosome phosphorylation. Here, we analyzed the role of γ-secretase in the stimulation of reverse ephrin-B2 signaling in the migration of mouse embryonic stem cell derived microglia. The proteolytic generation of the ephrin-B2 intracellular domain (ICD) by γ-secretase stimulates Src and focal adhesion kinase (FAK). Inhibition of γ-secretase decreased the phosphorylation of Src and FAK, and reduced cell motility. These effects were associated with enlargement of the podosomal surface. Interestingly, expression of ephrin-B2 ICD could rescue these effects, indicating that this proteolytic fragment mediates the activation of Src and FAK, and thereby regulates podosomal dynamics in microglial cells. Together, these results identify γ-secretase as well as ephrin-B2 as regulators of microglial migration.
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Affiliation(s)
- Nadja Kemmerling
- Department of Neurology, University of Bonn, Bonn, 53127, Germany
| | | | - Sandra Theil
- Department of Neurology, University of Bonn, Bonn, 53127, Germany
| | | | - Nils Hersch
- Institute of Complex Systems, ICS-7 Biomechanics, Forschungszentrum Jülich GmbH, Jülich, 52425, Germany
| | - Bernd Hoffmann
- Institute of Complex Systems, ICS-7 Biomechanics, Forschungszentrum Jülich GmbH, Jülich, 52425, Germany
| | - Michael T Heneka
- Department of Neurology, University of Bonn, Bonn, 53127, Germany.,German Center for Neurodegenerative Diseases, Bonn, 53127, Germany
| | - Bart de Strooper
- KULeuven Centre for Human Genetics, Leuven, 3000, Belgium.,Centre for Brain and Disease, VIB (Flanders Institute for Biotechnology), Leuven, 3000, Belgium
| | - Harald Neumann
- Institute of Reconstructive Neurobiology, University of Bonn, Bonn, 53127, Germany
| | - Jochen Walter
- Department of Neurology, University of Bonn, Bonn, 53127, Germany
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12
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Wei W, Wang H, Ji S. Paradoxes of the EphB1 receptor in malignant brain tumors. Cancer Cell Int 2017; 17:21. [PMID: 28194092 PMCID: PMC5299699 DOI: 10.1186/s12935-017-0384-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 01/20/2017] [Indexed: 02/07/2023] Open
Abstract
Eph receptors are a subfamily of receptor tyrosine kinases. Eph receptor-mediated forward and ephrin ligand-mediated reverse signalings are termed bidirectional signaling. Increasing evidence shows that Eph/ephrin signaling regulates cell migration, adhesion, morphological changes, differentiation, proliferation and survival through cell–cell communication. Some recent studies have started to implicate Eph/ephrin signaling in tumorigenesis, metastasis, and angiogenesis. Previous studies have shown that EphB1 receptor and its ephrin ligands are expressed in the central nervous system. EphB1/ephrin signaling plays an important role in the regulation of synapse formation and maturation, migration of neural progenitors, establishment of tissue patterns, and the development of immune organs. Besides, various recent studies have detected the abnormal expression of EphB1 receptor in different brain tumors. However, the underlying molecular mechanisms of EphB1/ephrins signaling in the development of these tumors are not fully understood. This review focuses on EphB1 that has both tumor-suppressing and -promoting roles in some brain tumors. Understanding the intracellular mechanisms of EphB1 in tumorigenesis and metastasis of brain tumors might provide a foundation for the development of EphB1-targeted therapies.
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Affiliation(s)
- Wenqiang Wei
- Laboratory of Cell Signal Transduction, Medical School, Henan University, Kaifeng, 475004 China.,Department of Microbiology, Medical School, Henan University, Kaifeng, 475004 China
| | - Hongju Wang
- Department of Anatomy, Medical School, Henan University, Kaifeng, 475004 China
| | - Shaoping Ji
- Laboratory of Cell Signal Transduction, Medical School, Henan University, Kaifeng, 475004 China.,Department of Oncology, The First Affiliated Hospital, Henan University, Kaifeng, 475001 China
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13
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Embryonic interneurons from the medial, but not the caudal ganglionic eminence trigger ocular dominance plasticity in adult mice. Brain Struct Funct 2016; 222:539-547. [PMID: 27165433 DOI: 10.1007/s00429-016-1232-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 04/28/2016] [Indexed: 10/21/2022]
Abstract
The maturation of cortical inhibition provided by parvalbumin-containing basket cells derived from the medial ganglionic eminence (MGE) is a key event in starting the enhanced visual cortical plasticity during the critical period. Although it is generally assumed that a further increase in inhibition closes the critical period again, it was recently shown that embryonic interneurons derived from the MGE can induce an additional, artificial critical period when injected into the visual cortex of young mice. It has, however, remained open whether this effect was indeed specific for MGE-derived cells, and whether critical period-like plasticity could also be induced in fully adult animals. To clarify these issues, we injected explants from either the MGE or the caudal ganglionic eminence (CGE) into the visual cortices of fully adult mice, and performed monocular deprivation 33 days later for 4 days. Animals implanted with MGE cells, but not with CGE cells, showed marked ocular dominance plasticity. Immunohistochemistry confirmed that the injected cells from both sources migrated far in the host cortex, that most developed into neurons producing GABA, and that only cells from the MGE expressed parvalbumin. Thus, our results confirm that the plasticity-inducing effect of embryonic interneurons is specific for cells from the MGE, and is independent of the host animal's age.
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Abstract
Ephrins and Eph receptors enable contact-mediated interactions between cells at every stage of nervous system development. In spite of their broad binding affinities, Eph proteins facilitate specificity in neuronal migration and axon targeting. This review focuses on recent studies that demonstrate how these proteins interact with each other, and with other signaling pathways, to guide specificity in a diverse set of developmental processes.
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Affiliation(s)
- Karina S Cramer
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, USA
| | - Ilona J Miko
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, USA
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