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Tomar M, Beros J, Meloni B, Rodger J. Interactions between Guidance Cues and Neuronal Activity: Therapeutic Insights from Mouse Models. Int J Mol Sci 2023; 24:ijms24086966. [PMID: 37108129 PMCID: PMC10138948 DOI: 10.3390/ijms24086966] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 03/31/2023] [Accepted: 04/03/2023] [Indexed: 04/29/2023] Open
Abstract
Topographic mapping of neural circuits is fundamental in shaping the structural and functional organization of brain regions. This developmentally important process is crucial not only for the representation of different sensory inputs but also for their integration. Disruption of topographic organization has been associated with several neurodevelopmental disorders. The aim of this review is to highlight the mechanisms involved in creating and refining such well-defined maps in the brain with a focus on the Eph and ephrin families of axon guidance cues. We first describe the transgenic models where ephrin-A expression has been manipulated to understand the role of these guidance cues in defining topography in various sensory systems. We further describe the behavioral consequences of lacking ephrin-A guidance cues in these animal models. These studies have given us unexpected insight into how neuronal activity is equally important in refining neural circuits in different brain regions. We conclude the review by discussing studies that have used treatments such as repetitive transcranial magnetic stimulation (rTMS) to manipulate activity in the brain to compensate for the lack of guidance cues in ephrin-knockout animal models. We describe how rTMS could have therapeutic relevance in neurodevelopmental disorders with disrupted brain organization.
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Affiliation(s)
- Maitri Tomar
- School of Biological Sciences, The University of Western Australia, Crawley, WA 6009, Australia
- Perron Institute for Neurological and Translational Science, Nedlands, WA 6009, Australia
| | - Jamie Beros
- School of Biological Sciences, The University of Western Australia, Crawley, WA 6009, Australia
- Perron Institute for Neurological and Translational Science, Nedlands, WA 6009, Australia
| | - Bruno Meloni
- Perron Institute for Neurological and Translational Science, Nedlands, WA 6009, Australia
- Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Crawley, WA 6009, Australia
- Department of Neurosurgery, Sir Charles Gairdner Hospital, QEII Medical Centre, Nedlands, WA 6009, Australia
| | - Jennifer Rodger
- School of Biological Sciences, The University of Western Australia, Crawley, WA 6009, Australia
- Perron Institute for Neurological and Translational Science, Nedlands, WA 6009, Australia
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2
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Shi Y, Liu Y, Wu C, Liu X, Hu W, Yang Z, Li Z, Li Y, Deng C, Wei K, Gu C, Chen X, Su W, Zhuo Y. N,N-Dimethyl-3β-hydroxycholenamide attenuates neuronal death and retinal inflammation in retinal ischemia/reperfusion injury by inhibiting Ninjurin 1. J Neuroinflammation 2023; 20:91. [PMID: 37029422 PMCID: PMC10082498 DOI: 10.1186/s12974-023-02754-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 03/01/2023] [Indexed: 04/09/2023] Open
Abstract
BACKGROUND Retinal ischemia-reperfusion (RIR) injury refers to an obstruction in the retinal blood supply followed by reperfusion. Although the molecular mechanism underlying the ischemic pathological cascade is not fully understood, neuroinflammation plays a crucial part in the mortality of retinal ganglion cells. METHODS Single-cell RNA sequencing (scRNA-seq), molecular docking, and transfection assay were used to explore the effectiveness and pathogenesis of N,N-dimethyl-3β-hydroxycholenamide (DMHCA)-treated mice with RIR injury and DMHCA-treated microglia after oxygen and glucose deprivation/reoxygenation (OGD/R). RESULTS DMHCA could suppress inflammatory gene expression and attenuate neuronal lesions, restoring the retinal structure in vivo. Using scRNA-seq on the retina of DMHCA-treated mice, we provided novel insights into RIR immunity and demonstrated nerve injury-induced protein 1 (Ninjurin1/Ninj 1) as a promising treatment target for RIR. Moreover, the expression of Ninj1, which was increased in RIR injury and OGD/R-treated microglia, was downregulated in the DMHCA-treated group. DMHCA suppressed the activation of the nuclear factor kappa B (NF-κB) pathways induced by OGD/R, which was undermined by the NF-κB pathway agonist betulinic acid. Overexpressed Ninj1 reversed the anti-inflammatory and anti-apoptotic function of DMHCA. Molecular docking indicated that for Ninj1, DMHCA had a low binding energy of - 6.6 kcal/mol, suggesting highly stable binding. CONCLUSION Ninj1 may play a pivotal role in microglia-mediated inflammation, while DMHCA could be a potential treatment strategy against RIR injury.
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Affiliation(s)
- Yunhong Shi
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, 510060, Guangdong, China
| | - Yidan Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, 510060, Guangdong, China
| | - Caiqing Wu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, 510060, Guangdong, China
| | - Xiuxing Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, 510060, Guangdong, China
| | - Wenfei Hu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, 510060, Guangdong, China
| | - Zhenlan Yang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, 510060, Guangdong, China
| | - Zhidong Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, 510060, Guangdong, China
| | - Yangyang Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, 510060, Guangdong, China
| | - Caibin Deng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, 510060, Guangdong, China
| | - Kun Wei
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, 510060, Guangdong, China
| | - Chenyang Gu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, 510060, Guangdong, China
| | - Xuhao Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, 510060, Guangdong, China
| | - Wenru Su
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, 510060, Guangdong, China.
| | - Yehong Zhuo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Sun Yat-Sen University, No. 7 Jinsui Road, Tianhe District, Guangzhou, 510060, Guangdong, China.
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3
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Superior segmental optic nerve hypoplasia: A review. Surv Ophthalmol 2022; 67:1467-1475. [DOI: 10.1016/j.survophthal.2022.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 02/14/2022] [Accepted: 02/15/2022] [Indexed: 11/18/2022]
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4
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The influence of spontaneous and visual activity on the development of direction selectivity maps in mouse retina. Cell Rep 2022; 38:110225. [PMID: 35021080 PMCID: PMC8805704 DOI: 10.1016/j.celrep.2021.110225] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 11/11/2021] [Accepted: 12/10/2021] [Indexed: 01/23/2023] Open
Abstract
In mice, retinal direction selectivity is organized in a map that aligns to the body and gravitational axes of optic flow, and little is known about how this map develops. We find direction selectivity maps are largely present at eye opening and develop normally in the absence of visual experience. Remarkably, in mice lacking the beta2 subunit of neuronal nicotinic acetylcholine receptors (β2-nAChR-KO), which exhibit drastically reduced cholinergic retinal waves in the first postnatal week, selectivity to horizontal motion is absent while selectivity to vertical motion remains. We tested several possible mechanisms that could explain the loss of horizontal direction selectivity in β2-nAChR-KO mice (wave propagation bias, FRMD7 expression, starburst amacrine cell morphology), but all were found to be intact when compared with WT mice. This work establishes a role for retinal waves in the development of asymmetric circuitry that mediates retinal direction selectivity via an unknown mechanism.
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Johnson KO, Triplett JW. Wiring subcortical image-forming centers: Topography, laminar targeting, and map alignment. Curr Top Dev Biol 2020; 142:283-317. [PMID: 33706920 DOI: 10.1016/bs.ctdb.2020.10.004] [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] [Indexed: 02/09/2023]
Abstract
Efficient sensory processing is a complex and important function for species survival. As such, sensory circuits are highly organized to facilitate rapid detection of salient stimuli and initiate motor responses. For decades, the retina's projections to image-forming centers have served as useful models to elucidate the mechanisms by which such exquisite circuitry is wired. In this chapter, we review the roles of molecular cues, neuronal activity, and axon-axon competition in the development of topographically ordered retinal ganglion cell (RGC) projections to the superior colliculus (SC) and dorsal lateral geniculate nucleus (dLGN). Further, we discuss our current state of understanding regarding the laminar-specific targeting of subclasses of RGCs in the SC and its homolog, the optic tectum (OT). Finally, we cover recent studies examining the alignment of projections from primary visual cortex with RGCs that monitor the same region of space in the SC.
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Affiliation(s)
- Kristy O Johnson
- Center for Neuroscience Research, Children's National Research Institute, Washington, DC, United States; Institute for Biomedical Sciences, The George Washington University School of Medicine, Washington, DC, United States
| | - Jason W Triplett
- Center for Neuroscience Research, Children's National Research Institute, Washington, DC, United States; Department of Pediatrics, The George Washington University School of Medicine, Washington, DC, United States.
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6
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Vigouroux RJ, Cesar Q, Chédotal A, Nguyen-Ba-Charvet KT. Revisiting the role of Dcc in visual system development with a novel eye clearing method. eLife 2020; 9:51275. [PMID: 32096760 PMCID: PMC7062470 DOI: 10.7554/elife.51275] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 02/24/2020] [Indexed: 12/22/2022] Open
Abstract
The Deleted in Colorectal Carcinoma (Dcc) receptor plays a critical role in optic nerve development. Whilst Dcc is expressed postnatally in the eye, its function remains unknown as Dcc knockouts die at birth. To circumvent this drawback, we generated an eye-specific Dcc mutant. To study the organization of the retina and visual projections in these mice, we also established EyeDISCO, a novel tissue clearing protocol that removes melanin allowing 3D imaging of whole eyes and visual pathways. We show that in the absence of Dcc, some ganglion cell axons stalled at the optic disc, whereas others perforated the retina, separating photoreceptors from the retinal pigment epithelium. A subset of visual axons entered the CNS, but these projections are perturbed. Moreover, Dcc-deficient retinas displayed a massive postnatal loss of retinal ganglion cells and a large fraction of photoreceptors. Thus, Dcc is essential for the development and maintenance of the retina.
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Affiliation(s)
- Robin J Vigouroux
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, Paris, France
| | - Quénol Cesar
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, Paris, France
| | - Alain Chédotal
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, Paris, France
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7
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Harada H, Farhani N, Wang XF, Sugita S, Charish J, Attisano L, Moran M, Cloutier JF, Reber M, Bremner R, Monnier PP. Extracellular phosphorylation drives the formation of neuronal circuitry. Nat Chem Biol 2019; 15:1035-1042. [PMID: 31451763 DOI: 10.1038/s41589-019-0345-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 07/14/2019] [Indexed: 12/29/2022]
Abstract
Until recently, the existence of extracellular kinase activity was questioned. Many proteins of the central nervous system are targeted, but it remains unknown whether, or how, extracellular phosphorylation influences brain development. Here we show that the tyrosine kinase vertebrate lonesome kinase (VLK), which is secreted by projecting retinal ganglion cells, phosphorylates the extracellular protein repulsive guidance molecule b (RGMb) in a dorsal-ventral descending gradient. Silencing of VLK or RGMb causes aberrant axonal branching and severe axon misguidance in the chick optic tectum. Mice harboring RGMb with a point mutation in the phosphorylation site also display aberrant axonal pathfinding. Mechanistic analyses show that VLK-mediated RGMb phosphorylation modulates Wnt3a activity by regulating LRP5 protein gradients. Thus, the secretion of VLK by projecting neurons provides crucial signals for the accurate formation of nervous system circuitry. The dramatic effect of VLK on RGMb and Wnt3a signaling implies that extracellular phosphorylation likely has broad and profound effects on brain development, function and disease.
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Affiliation(s)
- Hidekiyo Harada
- Krembil Research Institute, Vision Division, Krembil Discovery Tower, Toronto, Ontario, Canada
| | - Nahal Farhani
- Krembil Research Institute, Vision Division, Krembil Discovery Tower, Toronto, Ontario, Canada
| | - Xue-Fan Wang
- Krembil Research Institute, Vision Division, Krembil Discovery Tower, Toronto, Ontario, Canada
| | - Shuzo Sugita
- Krembil Research Institute, Vision Division, Krembil Discovery Tower, Toronto, Ontario, Canada
| | - Jason Charish
- Krembil Research Institute, Vision Division, Krembil Discovery Tower, Toronto, Ontario, Canada.,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Liliana Attisano
- Department of Biochemistry, Donnelly Center, University of Toronto, Toronto, Ontario, Canada
| | - Michael Moran
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | | | - Michael Reber
- Krembil Research Institute, Vision Division, Krembil Discovery Tower, Toronto, Ontario, Canada.,Department of Ophthalmology and Vision Sciences, Faculty of Medicine, University of Toronto, Ontario, Toronto, Canada.,CNRS UPR3212, University of Strasbourg, Strasbourg, France
| | - Rod Bremner
- Lunenfeld Tannenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Philippe P Monnier
- Krembil Research Institute, Vision Division, Krembil Discovery Tower, Toronto, Ontario, Canada. .,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada. .,Department of Ophthalmology and Vision Sciences, Faculty of Medicine, University of Toronto, Ontario, Toronto, Canada.
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8
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Murcia-Belmonte V, Erskine L. Wiring the Binocular Visual Pathways. Int J Mol Sci 2019; 20:ijms20133282. [PMID: 31277365 PMCID: PMC6651880 DOI: 10.3390/ijms20133282] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 06/29/2019] [Accepted: 07/03/2019] [Indexed: 02/06/2023] Open
Abstract
Retinal ganglion cells (RGCs) extend axons out of the retina to transmit visual information to the brain. These connections are established during development through the navigation of RGC axons along a relatively long, stereotypical pathway. RGC axons exit the eye at the optic disc and extend along the optic nerves to the ventral midline of the brain, where the two nerves meet to form the optic chiasm. In animals with binocular vision, the axons face a choice at the optic chiasm—to cross the midline and project to targets on the contralateral side of the brain, or avoid crossing the midline and project to ipsilateral brain targets. Ipsilaterally and contralaterally projecting RGCs originate in disparate regions of the retina that relate to the extent of binocular overlap in the visual field. In humans virtually all RGC axons originating in temporal retina project ipsilaterally, whereas in mice, ipsilaterally projecting RGCs are confined to the peripheral ventrotemporal retina. This review will discuss recent advances in our understanding of the mechanisms regulating specification of ipsilateral versus contralateral RGCs, and the differential guidance of their axons at the optic chiasm. Recent insights into the establishment of congruent topographic maps in both brain hemispheres also will be discussed.
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Affiliation(s)
| | - Lynda Erskine
- School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, Scotland AB25 2ZD, UK
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9
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Murcia-Belmonte V, Coca Y, Vegar C, Negueruela S, de Juan Romero C, Valiño AJ, Sala S, DaSilva R, Kania A, Borrell V, Martinez LM, Erskine L, Herrera E. A Retino-retinal Projection Guided by Unc5c Emerged in Species with Retinal Waves. Curr Biol 2019; 29:1149-1160.e4. [PMID: 30905607 PMCID: PMC6453780 DOI: 10.1016/j.cub.2019.02.052] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 01/04/2019] [Accepted: 02/22/2019] [Indexed: 12/29/2022]
Abstract
The existence of axons extending from one retina to the other has been reported during perinatal development in different vertebrates. However, it has been thought that these axons are either a labeling artifact or misprojections. Here, we show unequivocally that a small subset of retinal ganglion cells (RGCs) project to the opposite retina and that the guidance receptor Unc5c, expressed in the retinal region where the retinal-retinal (R-R) RGCs are located, is necessary and sufficient to guide axons to the opposite retina. In addition, Netrin1, an Unc5c ligand, is expressed in the ventral diencephalon in a pattern that is consistent with impeding the growth of Unc5c-positive retinal axons into the brain. We also have generated a mathematical model to explore the formation of retinotopic maps in the presence and absence of a functional connection between both eyes. This model predicts that an R-R connection is required for the bilateral coordination of axonal refinement in species where refinement depends upon spontaneous retinal waves. Consistent with this idea, the retinal expression of Unc5c correlates with the existence and size of an R-R projection in different species and with the extent of axonal refinement in visual targets. These findings demonstrate that active guidance drives the formation of the R-R projection and suggest an important role for these projections in visual mapping to ensure congruent bilateral refinement. A subset of retinal ganglion cells project to the contralateral retina Unc5c mediates the formation of the retina-retina projection Unc5c retinal expression correlates with extent of refinement in visual targets Congruency of visual maps in species with retinal waves may rely on R-R axons
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Affiliation(s)
- Verónica Murcia-Belmonte
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández, CSIC-UMH, Av. Santiago Ramón y Cajal s/n, Sant Joan d'Alacant 03550, Alicante, Spain
| | - Yaiza Coca
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández, CSIC-UMH, Av. Santiago Ramón y Cajal s/n, Sant Joan d'Alacant 03550, Alicante, Spain
| | - Celia Vegar
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández, CSIC-UMH, Av. Santiago Ramón y Cajal s/n, Sant Joan d'Alacant 03550, Alicante, Spain
| | - Santiago Negueruela
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández, CSIC-UMH, Av. Santiago Ramón y Cajal s/n, Sant Joan d'Alacant 03550, Alicante, Spain
| | - Camino de Juan Romero
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández, CSIC-UMH, Av. Santiago Ramón y Cajal s/n, Sant Joan d'Alacant 03550, Alicante, Spain
| | - Arturo José Valiño
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández, CSIC-UMH, Av. Santiago Ramón y Cajal s/n, Sant Joan d'Alacant 03550, Alicante, Spain
| | - Salvador Sala
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández, CSIC-UMH, Av. Santiago Ramón y Cajal s/n, Sant Joan d'Alacant 03550, Alicante, Spain
| | - Ronan DaSilva
- Institut de Recherches Cliniques de Montréal (IRCM), 110, ave. des Pins Ouest, Montréal, QC H2W 1R7, Canada
| | - Artur Kania
- Institut de Recherches Cliniques de Montréal (IRCM), 110, ave. des Pins Ouest, Montréal, QC H2W 1R7, Canada; Division of Experimental Medicine, Department of Anatomy and Cell Biology, McGill University, Montréal, QC H3A 2B2, Canada
| | - Víctor Borrell
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández, CSIC-UMH, Av. Santiago Ramón y Cajal s/n, Sant Joan d'Alacant 03550, Alicante, Spain
| | - Luis M Martinez
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández, CSIC-UMH, Av. Santiago Ramón y Cajal s/n, Sant Joan d'Alacant 03550, Alicante, Spain
| | - Lynda Erskine
- School of Medicine, Medical Sciences and Nutrition, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, Scotland, UK
| | - Eloísa Herrera
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández, CSIC-UMH, Av. Santiago Ramón y Cajal s/n, Sant Joan d'Alacant 03550, Alicante, Spain.
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10
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Protein Tyrosine Phosphatase Receptor Type J (PTPRJ) Regulates Retinal Axonal Projections by Inhibiting Eph and Abl Kinases in Mice. J Neurosci 2018; 38:8345-8363. [PMID: 30082414 DOI: 10.1523/jneurosci.0128-18.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 07/05/2018] [Accepted: 07/30/2018] [Indexed: 12/28/2022] Open
Abstract
Eph receptors play pivotal roles in the axon guidance of retinal ganglion cells (RGCs) at the optic chiasm and the establishment of the topographic retinocollicular map. We previously demonstrated that protein tyrosine phosphatase receptor type O (PTPRO) is specifically involved in the control of retinotectal projections in chicks through the dephosphorylation of EphA and EphB receptors. We subsequently revealed that all the mouse R3 subfamily members (PTPRB, PTPRH, PTPRJ, and PTPRO) of the receptor protein tyrosine phosphatase (RPTP) family inhibited Eph receptors as their substrates in cultured mammalian cells. We herein investigated the functional roles of R3 RPTPs in the projection of mouse retinal axon of both sexes. Ptpro and Ptprj were expressed in mouse RGCs; however, Ptprj expression levels were markedly higher than those of Ptpro Consistent with their expression levels, Eph receptor activity was significantly enhanced in Ptprj-knock-out (Ptprj-KO) retinas. In Ptprj-KO and Ptprj/Ptpro-double-KO (DKO) mice, the number of retinal axons that projected ipsilaterally or to the contralateral eye was significantly increased. Furthermore, retinal axons in Ptprj-KO and DKO mice formed anteriorly shifted ectopic terminal zones in the superior colliculus (SC). We found that c-Abl (Abelson tyrosine kinase) was downstream of ephrin-Eph signaling for the repulsion of retinal axons at the optic chiasm and in the SC. c-Abl was identified as a novel substrate for PTPRJ and PTPRO, and the phosphorylation of c-Abl was upregulated in Ptprj-KO and DKO retinas. Thus, PTPRJ regulates retinocollicular projections in mice by controlling the activity of Eph and c-Abl kinases.SIGNIFICANCE STATEMENT Correct retinocollicular projection is a prerequisite for proper vision. Eph receptors have been implicated in retinal axon guidance at the optic chiasm and the establishment of the topographic retinocollicular map. We herein demonstrated that protein tyrosine phosphatase receptor type J (PTPRJ) regulated retinal axonal projections by controlling Eph activities. The retinas of Ptprj-knock-out (KO) and Ptpro/Ptprj double-KO mice exhibited significantly enhanced Eph activities over those in wild-type mice, and their axons showed defects in pathfinding at the chiasm and retinocollicular topographic map formation. We also revealed that c-Abl (Abelson tyrosine kinase) downstream of Eph receptors was regulated by PTPRJ. These results indicate that the regulation of the ephrin-Eph-c-Abl axis by PTPRJ plays pivotal roles in the proper central projection of retinal axons during development.
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11
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Guidance of retinal axons in mammals. Semin Cell Dev Biol 2017; 85:48-59. [PMID: 29174916 DOI: 10.1016/j.semcdb.2017.11.027] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2017] [Revised: 11/17/2017] [Accepted: 11/20/2017] [Indexed: 11/21/2022]
Abstract
In order to navigate through the surrounding environment many mammals, including humans, primarily rely on vision. The eye, composed of the choroid, sclera, retinal pigmented epithelium, cornea, lens, iris and retina, is the structure that receives the light and converts it into electrical impulses. The retina contains six major types of neurons involving in receiving and modifying visual information and passing it onto higher visual processing centres in the brain. Visual information is relayed to the brain via the axons of retinal ganglion cells (RGCs), a projection known as the optic pathway. The proper formation of this pathway during development is essential for normal vision in the adult individual. Along this pathway there are several points where visual axons face 'choices' in their direction of growth. Understanding how these choices are made has advanced significantly our knowledge of axon guidance mechanisms. Thus, the development of the visual pathway has served as an extremely useful model to reveal general principles of axon pathfinding throughout the nervous system. However, due to its particularities, some cellular and molecular mechanisms are specific for the visual circuit. Here we review both general and specific mechanisms involved in the guidance of mammalian RGC axons when they are traveling from the retina to the brain to establish precise and stereotyped connections that will sustain vision.
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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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13
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Kwak H, Salvucci O, Weigert R, Martinez-Torrecuadrada JL, Henkemeyer M, Poulos MG, Butler JM, Tosato G. Sinusoidal ephrin receptor EPHB4 controls hematopoietic progenitor cell mobilization from bone marrow. J Clin Invest 2016; 126:4554-4568. [PMID: 27820703 PMCID: PMC5127687 DOI: 10.1172/jci87848] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 09/29/2016] [Indexed: 12/27/2022] Open
Abstract
Hematopoietic stem and progenitor cells (HSPCs) reside in the bone marrow. Stress signals from cancer and other conditions promote HSPC mobilization into circulation and subsequent homing to tissue microenvironments. HSPC infiltration into tissue microenvironments can influence disease progression; notably, in cancer, HSPCs encourage tumor growth. Here we have uncovered a mutually exclusive distribution of EPHB4 receptors in bone marrow sinusoids and ephrin B2 ligands in hematopoietic cells. We determined that signaling interactions between EPHB4 and ephrin B2 control HSPC mobilization from the bone marrow. In mice, blockade of the EPHB4/ephrin B2 signaling pathway reduced mobilization of HSPCs and other myeloid cells to the circulation. EPHB4/ephrin B2 blockade also reduced HSPC infiltration into tumors as well as tumor progression in murine models of melanoma and mammary cancer. These results identify EPHB4/ephrin B2 signaling as critical to HSPC mobilization from bone marrow and provide a potential strategy for reducing cancer progression by targeting the bone marrow.
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Affiliation(s)
- Hyeongil Kwak
- Laboratory of Cellular Oncology, Center for Cancer Research (CCR), National Cancer Institute (NCI), NIH, and
| | - Ombretta Salvucci
- Laboratory of Cellular Oncology, Center for Cancer Research (CCR), National Cancer Institute (NCI), NIH, and
| | - Roberto Weigert
- National Institute of Dental and Craniofacial Research (NIDCR) and Laboratory of Cellular and Molecular Biology, NCI, NIH, Bethesda, Maryland, USA
| | | | - Mark Henkemeyer
- Department of Developmental Biology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Michael G. Poulos
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, USA
| | - Jason M. Butler
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, USA
| | - Giovanna Tosato
- Laboratory of Cellular Oncology, Center for Cancer Research (CCR), National Cancer Institute (NCI), NIH, and
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14
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Oweida A, Bhatia S, Hirsch K, Calame D, Griego A, Keysar S, Pitts T, Sharma J, Eckhardt G, Jimeno A, Wang XJ, Parkash G, Califano J, Karam SD. Ephrin-B2 overexpression predicts for poor prognosis and response to therapy in solid tumors. Mol Carcinog 2016; 56:1189-1196. [PMID: 27649287 DOI: 10.1002/mc.22574] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Revised: 09/16/2016] [Accepted: 09/16/2016] [Indexed: 12/14/2022]
Abstract
Ephrin B2 is variably expressed on tumor cells and its blockade has been shown to inhibit angiogenesis in animal models of pancreatic, colorectal, lung and head, and neck squamous cell carcinomas. However, the implications of ephrinB2 expression in cancer patients have remained elusive. In this study, we analyzed the cancer genome atlas (TCGA) for ephrinB2 expression. We report significant correlations between EFNB2 expression, overall survival and disease-free survival in head and neck squamous cell carcinoma (HNSCC, n = 519), pancreatic adenocarcinoma (n = 186), and bladder urothelial carcinoma (n = 410). In HNSCC patients, high-EFNB2 mRNA expression was associated with tumor HPV negativity, oral cavity location, alcohol intake, higher TP53 mutation, and EGFR amplification. EphrinB2 overexpression also correlated with worse response to chemotherapy and radiotherapy. The therapeutic potential of blocking ephrinB2 was validated in HNSCC patient-derived tumor xenografts and showed significant improvement in survival and tumor growth delay. Our data shows that ephrinB2 overexpression can serve as a critical biomarker for patient prognosis and response to therapy. These results should guide design of future clinical trials exploring EphrinB2 inhibition in cancer patients. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Ayman Oweida
- Department of Radiation Oncology, Anschutz Medical Campus, University of Colorado Denver, Denver, Colorado
| | - Shilpa Bhatia
- Department of Radiation Oncology, Anschutz Medical Campus, University of Colorado Denver, Denver, Colorado
| | - Kellen Hirsch
- Department of Radiation Oncology, Anschutz Medical Campus, University of Colorado Denver, Denver, Colorado
| | - Dylan Calame
- Department of Radiation Oncology, Anschutz Medical Campus, University of Colorado Denver, Denver, Colorado
| | - Anastacia Griego
- Department of Radiation Oncology, Anschutz Medical Campus, University of Colorado Denver, Denver, Colorado
| | - Steve Keysar
- Department of Oncology, Anschutz Medical Campus, University of Colorado Denver, Denver, Colorado
| | - Todd Pitts
- Division of Medical Oncology, Anschutz Medical Campus, University of Colorado Denver, Denver, Colorado
| | - Jaspreet Sharma
- Department of Radiation Oncology, Anschutz Medical Campus, University of Colorado Denver, Denver, Colorado
| | - Gail Eckhardt
- Division of Medical Oncology, Anschutz Medical Campus, University of Colorado Denver, Denver, Colorado
| | - Antonio Jimeno
- Department of Oncology, Anschutz Medical Campus, University of Colorado Denver, Denver, Colorado
| | - Xiao Jing Wang
- Department of Pathology, Anschutz Medical Campus, University of Colorado Denver, Aurora, Colorado
| | - Gill Parkash
- Vasgene Therapeutics, Los Angeles, California.,Department of Oncology, University of Southern California, Los Angeles, Southern California
| | - Joseph Califano
- Department of Otolaryngology, University of Southern California, San Diego, Southern California
| | - Sana D Karam
- Department of Radiation Oncology, Anschutz Medical Campus, University of Colorado Denver, Denver, Colorado
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15
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Eph receptor interclass cooperation is required for the regulation of cell proliferation. Exp Cell Res 2016; 348:10-22. [PMID: 27565439 DOI: 10.1016/j.yexcr.2016.08.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 08/21/2016] [Indexed: 11/21/2022]
Abstract
Cancer often arises by the constitutive activation of mitogenic pathways by mutations in stem cells. Eph receptors are unusual in that although they regulate the proliferation of stem/progenitor cells in many adult organs, they typically fail to transform cells. Multiple ephrins and Eph receptors are often co-expressed and are thought to be redundant, but we here describe an unexpected dichotomy with two homologous ligands, ephrin-B1 and ephrin-B2, regulating specifically migration or proliferation in the intestinal stem cell niche. We demonstrate that the combined activity of two different coexpressed Eph receptors of the A and B class assembled into common signaling clusters in response to ephrin-B2 is required for mitogenic signaling. The requirement of two different Eph receptors to convey mitogenic signals identifies a new type of cooperation within this receptor family and helps explain why constitutive activation of a single receptor fails to transform cells.
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16
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Wang J, Galvao J, Beach KM, Luo W, Urrutia RA, Goldberg JL, Otteson DC. Novel Roles and Mechanism for Krüppel-like Factor 16 (KLF16) Regulation of Neurite Outgrowth and Ephrin Receptor A5 (EphA5) Expression in Retinal Ganglion Cells. J Biol Chem 2016; 291:18084-95. [PMID: 27402841 DOI: 10.1074/jbc.m116.732339] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Indexed: 11/06/2022] Open
Abstract
Regenerative medicine holds great promise for the treatment of degenerative retinal disorders. Krüppel-like factors (KLFs) are transcription factors that have recently emerged as key tools in regenerative medicine because some of them can function as epigenetic reprogrammers in stem cell biology. Here, we show that KLF16, one of the least understood members of this family, is a POU4F2 independent transcription factor in retinal ganglion cells (RGCs) as early as embryonic day 15. When overexpressed, KLF16 inhibits RGC neurite outgrowth and enhances RGC growth cone collapse in response to exogenous ephrinA5 ligands. Ephrin/EPH signaling regulates RGC connectivity. The EphA5 promoter contains multiple GC- and GT-rich KLF-binding sites, which, as shown by ChIP-assays, bind KLF16 in vivo In electrophoretic mobility shift assays, KLF16 binds specifically to a single KLF site near the EphA5 transcription start site that is required for KLF16 transactivation. Interestingly, methylation of only six of 98 CpG dinucleotides within the EphA5 promoter blocks its transactivation by KLF16 but enables transactivation by KLF2 and KLF15. These data demonstrate a role for KLF16 in regulation of RGC neurite outgrowth and as a methylation-sensitive transcriptional regulator of EphA5 expression. Together, these data identify differential low level methylation as a novel mechanism for regulating KLF16-mediated EphA5 expression across the retina. Because of the critical role of ephrin/EPH signaling in patterning RGC connectivity, understanding the role of KLFs in regulating neurite outgrowth and Eph receptor expression will be vital for successful restoration of functional vision through optic nerve regenerative therapies.
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Affiliation(s)
- Jianbo Wang
- From the Departments of Physiological Optics and Vision Science and
| | - Joana Galvao
- the Byers Eye Institute, School of Medicine, Stanford University, Palo Alto, California 94303, the Shiley Eye Institute, University of California San Diego, La Jolla, California 92093, and
| | - Krista M Beach
- From the Departments of Physiological Optics and Vision Science and
| | - Weijia Luo
- Biology and Biochemistry, University of Houston, Houston, Texas 77204
| | - Raul A Urrutia
- the Laboratory of Epigenetics and Chromatin Dynamics, Gastroenterology Research Unit, Epigenomics Translational Program, Center for Individualized Medicine, Departments of Medicine, Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905
| | - Jeffrey L Goldberg
- the Byers Eye Institute, School of Medicine, Stanford University, Palo Alto, California 94303, the Shiley Eye Institute, University of California San Diego, La Jolla, California 92093, and
| | - Deborah C Otteson
- From the Departments of Physiological Optics and Vision Science and Biology and Biochemistry, University of Houston, Houston, Texas 77204,
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17
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Mechanisms of ephrin-Eph signalling in development, physiology and disease. Nat Rev Mol Cell Biol 2016; 17:240-56. [PMID: 26790531 DOI: 10.1038/nrm.2015.16] [Citation(s) in RCA: 420] [Impact Index Per Article: 52.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Eph receptor Tyr kinases and their membrane-tethered ligands, the ephrins, elicit short-distance cell-cell signalling and thus regulate many developmental processes at the interface between pattern formation and morphogenesis, including cell sorting and positioning, and the formation of segmented structures and ordered neural maps. Their roles extend into adulthood, when ephrin-Eph signalling regulates neuronal plasticity, homeostatic events and disease processes. Recently, new insights have been gained into the mechanisms of ephrin-Eph signalling in different cell types, and into the physiological importance of ephrin-Eph in different organs and in disease, raising questions for future research directions.
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18
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Lewis AE, Hwa J, Wang R, Soriano P, Bush JO. Neural crest defects in ephrin-B2 mutant mice are non-autonomous and originate from defects in the vasculature. Dev Biol 2015; 406:186-95. [PMID: 26385750 DOI: 10.1016/j.ydbio.2015.08.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 08/28/2015] [Accepted: 08/29/2015] [Indexed: 10/23/2022]
Abstract
Ephrin-B2, a member of the Eph/ephrin family of cell signaling molecules, has been implicated in the guidance of cranial and trunk neural crest cells (NCC) and development of the branchial arches(BA), but detailed examination in mice has been hindered by embryonic lethality of Efnb2 null loss of function due to a requirement in angiogenic remodeling. To elucidate the developmental roles for Efnb2, we generated a conditional rescue knock-in allele that allows rescue of ephrin-B2 specifically in the vascular endothelium (VE), but is otherwise ephrin-B2 deficient. Restoration of ephrin-B2 expression specifically to the VE completely circumvents angiogenic phenotypes, indicating that the requirement of ephrin-B2 in angiogenesis is limited to the VE. Surprisingly, we find that expression of ephrin-B2 specifically in the VE is also sufficient for normal NCC migration and that conversely, embryos in which ephrin-B2 is absent specifically from the VE exhibit NCC migration and survival defects. Disruption of vascular development independent of loss of ephrin-B2 function also leads to defects in NCC and BA development. Together, these data indicate that direct ephrin-B2 signaling to NCCs is not required for NCC guidance, which instead depends on proper organization of the embryonic vasculature.
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Affiliation(s)
- Ace E Lewis
- Department of Cell and Tissue Biology, Program in Craniofacial Biology and Institute for Human Genetics, University of California, San Francisco, CA 94143, United States
| | - Jennifer Hwa
- Laboratory for Accelerated Vascular Research, Division of Vascular Surgery, Department of Surgery, University of California, San Francisco, CA 94143, United States
| | - Rong Wang
- Laboratory for Accelerated Vascular Research, Division of Vascular Surgery, Department of Surgery, University of California, San Francisco, CA 94143, United States
| | - Philippe Soriano
- Department of Developmental and Regenerative Biology, Mt. Sinai School of Medicine, New York, NY 10029, United States
| | - Jeffrey O Bush
- Department of Cell and Tissue Biology, Program in Craniofacial Biology and Institute for Human Genetics, University of California, San Francisco, CA 94143, United States.
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19
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Isolated Sagittal Synostosis in a Boy with Craniofrontonasal Dysplasia and a Novel EFNB1 Mutation. PLASTIC AND RECONSTRUCTIVE SURGERY-GLOBAL OPEN 2015; 3:e427. [PMID: 26180728 PMCID: PMC4494497 DOI: 10.1097/gox.0000000000000369] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 03/30/2015] [Indexed: 11/26/2022]
Abstract
Craniofrontonasal syndrome (CFNS) is a rare X-linked disorder that shows greater severity in females and is largely attributed to mutations in EFNB1. A 7-year-old boy presented with hypertelorism, broad nasal root, midfacial hypoplasia, mandibular prognathia, ptosis, and scaphocephaly was clinically diagnosed with CFNS. Three-dimensional computed tomographic scans confirmed the isolated sagittal synostosis. His mother also showed clinical features of CFNS, but less severe. Genetic tests uncovered a novel C to T mutation at nucleotide 466 (c.466C>T) in exon 1 of EFNB1 for both. To the best of our knowledge, this is the only reported incident of CFNS in a male child exhibiting isolated sagittal synostosis.
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20
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Takeuchi S, Katoh H, Negishi M. Eph/ephrin reverse signalling induces axonal retraction through RhoA/ROCK pathway. J Biochem 2015; 158:245-52. [PMID: 25922200 DOI: 10.1093/jb/mvv042] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 03/26/2015] [Indexed: 01/09/2023] Open
Abstract
Eph/ephrin signalling plays essential roles in various tissue developments, such as axon guidance, angiogenesis and tissue separation. Interaction between Ephs and ephrins upon cell-cell contact results in forward (towards Eph-expressing cells) and reverse (towards ephrin-expressing cells) signalling. Although the molecular mechanisms downstream of Eph/ephrin forward signalling have been extensively studied, the functions and intracellular molecular mechanisms of Eph/ephrin reverse signalling are not fully understood. Rho GTPases are key regulators of the actin cytoskeleton to regulate cell morphology. In this study, we revealed that stimulation with the extracellular domain of EphB2 to activate Eph/ephrin reverse signalling induced axonal retraction in hippocampal neurons. The reduction of axonal length and branching by Eph/ephrin reverse signalling was blocked by inhibition of RhoA or Rho-associated coiled-coil-containing protein kinase (ROCK). These results suggest that Eph/ephrin reverse signalling negatively regulates axonal outgrowth and branching through RhoA/ROCK pathway in hippocampal neurons.
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Affiliation(s)
- Shingo Takeuchi
- Laboratory of Molecular Neurobiology, Graduate School of Biostudies, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Hironori Katoh
- Laboratory of Molecular Neurobiology, Graduate School of Biostudies, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Manabu Negishi
- Laboratory of Molecular Neurobiology, Graduate School of Biostudies, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
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21
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EphB4 forward signalling regulates lymphatic valve development. Nat Commun 2015; 6:6625. [PMID: 25865237 PMCID: PMC4403310 DOI: 10.1038/ncomms7625] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 02/12/2015] [Indexed: 01/08/2023] Open
Abstract
Bidirectional signalling is regarded as a notable hallmark of the Eph-ephrin signalling system: Eph-dependent forward signalling in Eph-expressing cells and ephrin-dependent reverse signalling in Ephrin-expressing cells. The notion of ephrin-dependent reverse signalling derives from genetic experiments utilizing mice carrying mutations in the intracellular region of ephrinBs. Here we show that EphB4-dependent forward signalling regulates lymphatic valve development, a process previously thought to be regulated by ephrinB2-dependent reverse signalling. We develop antibodies that selectively target EphB4 and ephrinB2. We find that mice bearing genetically altered cytoplasmic region of ephrinB2 have significantly altered EphB4-dependent forward signalling. Selective inhibition of EphB4 using a functional blocking antibody results in defective lymphatic valve development. Furthermore, a chemical genetic approach is used to unequivocally show that the kinase activity of EphB4 is essential for lymphatic valve development.
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22
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Abstract
The visual system is beautifully crafted to transmit information of the external world to visual processing and cognitive centers in the brain. For visual information to be relayed to the brain, a series of axon pathfinding events must take place to ensure that the axons of retinal ganglion cells, the only neuronal cell type in the retina that sends axons out of the retina, find their way out of the eye to connect with targets in the brain. In the past few decades, the power of molecular and genetic tools, including the generation of genetically manipulated mouse lines, have multiplied our knowledge about the molecular mechanisms involved in the sculpting of the visual system. Here, we review major advances in our understanding of the mechanisms controlling the differentiation of RGCs, guidance of their axons from the retina to the primary visual centers, and the refinement processes essential for the establishment of topographic maps and eye-specific axon segregation. Human disorders, such as albinism and achiasmia, that impair RGC axon growth and guidance and, thus, the establishment of a fully functioning visual system will also be discussed.
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Affiliation(s)
- Lynda Erskine
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Scotland, UK
| | - Eloisa Herrera
- Instituto de Neurosciencias de Alicante, CSIC-UMH, San Juan de Alicante, Spain
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23
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McLaughlin T, Lim YS, Santiago A, O'Leary DDM. Multiple EphB receptors mediate dorsal-ventral retinotopic mapping via similar bi-functional responses to ephrin-B1. Mol Cell Neurosci 2014; 63:24-30. [PMID: 25051176 DOI: 10.1016/j.mcn.2014.05.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 05/23/2014] [Indexed: 11/30/2022] Open
Abstract
The projection from the retina to the superior colliculus in mice is organized in a retinotopic map that develops through the formation and guidance of interstitial branches extended by retinal ganglion cell axons. Bidirectional branch guidance along the lateral-medial collicular axis is critical to mapping the dorsal-ventral retinal axis. EphB receptor tyrosine kinases expressed in an overall low to high dorsal-ventral retinal gradient have been implicated in this mapping in response to the graded low to high lateral-medial expression of a ligand, ephrin-B1, in the superior colliculus. However, the relative contributions of EphBs and ephrin-B1 are not well understood. We examined EphB1, EphB2, and EphB3 mutant mice and find that each has ectopic arborizations of retinal axon branches lateral to their appropriate termination zone, with no qualitative differences in aberrant mapping, suggesting a similar role for each EphB. However, the frequency of cases with map defects progressively rises in compound EphB mutants coincident with the number of EphB null alleles from one to five of the six total alleles indicating that EphB level is critical. We analyzed branch extension in vitro and find that dorsal branches, with low EphB levels, exhibit a negative response to ephrin-B1, whereas ventral branches, with high EphB levels, exhibit a positive response to ephrin-B1. Using EphB mutant retina, we show that both of these differential branch extension responses are dependent on EphB level. Our findings show a bifunctional action of ephrin-B1 regulated by EphB levels that can account for the bidirectional extension of interstitial branches required to establish a retinotopic map.
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Affiliation(s)
- Todd McLaughlin
- Molecular Neurobiology Laboratory, The Salk Institute, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Yoo-Shick Lim
- Molecular Neurobiology Laboratory, The Salk Institute, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Alicia Santiago
- Molecular Neurobiology Laboratory, The Salk Institute, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Dennis D M O'Leary
- Molecular Neurobiology Laboratory, The Salk Institute, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
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24
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Bennett KM, Afanador MD, Lal CV, Xu H, Persad E, Legan SK, Chenaux G, Dellinger M, Savani RC, Dravis C, Henkemeyer M, Schwarz MA. Ephrin-B2 reverse signaling increases α5β1 integrin-mediated fibronectin deposition and reduces distal lung compliance. Am J Respir Cell Mol Biol 2014; 49:680-7. [PMID: 23742148 DOI: 10.1165/rcmb.2013-0002oc] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Alveolar growth abnormalities and severe respiratory dysfunction are often fatal. Identifying mechanisms that control epithelial proliferation and enlarged, poorly septated airspaces is essential in developing new therapies for lung disease. The membrane-bound ligand ephrin-B2 is strongly expressed in lung epithelium, and yet in contrast to its known requirement for arteriogenesis, considerably less is known regarding the function of this protein in the epithelium. We hypothesize that the vascular mediator ephrin-B2 governs alveolar growth and mechanics beyond the confines of the endothelium. We used the in vivo manipulation of ephrin-B2 reverse signaling to determine the role of this vascular mediator in the pulmonary epithelium and distal lung mechanics. We determined that the ephrin-B2 gene (EfnB2) is strongly expressed in alveolar Type 2 cells throughout development and into adulthood. The role of ephrin-B2 reverse signaling in the lung was assessed in Efnb2(LacZ/6YFΔV) mutants that coexpress the intracellular truncated ephrin-B2-β-galactosidase fusion and an intracellular point mutant ephrin-B2 protein that is unable to become tyrosine-phosphorylated or to interact with either the SH2 or PDZ domain-containing downstream signaling proteins. In these viable mice, we observed pulmonary hypoplasia and altered pulmonary mechanics, as evidenced by a marked reduction in lung compliance. Associated with the reduction in lung compliance was a significant increase in insoluble fibronectin (FN) basement membrane matrix assembly with FN deposition, and a corresponding increase in the α5 integrin receptor required for FN fibrillogenesis. These experiments indicate that ephrin-B2 reverse signaling mediates distal alveolar formation, fibrillogenesis, and pulmonary compliance.
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25
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Dai J, Buhusi M, Demyanenko GP, Brennaman LH, Hruska M, Dalva MB, Maness PF. Neuron glia-related cell adhesion molecule (NrCAM) promotes topographic retinocollicular mapping. PLoS One 2013; 8:e73000. [PMID: 24023801 PMCID: PMC3759449 DOI: 10.1371/journal.pone.0073000] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Accepted: 07/16/2013] [Indexed: 11/18/2022] Open
Abstract
NrCAM (Neuron-glial related cell adhesion molecule), a member of the L1 family of cell adhesion molecules, reversibly binds ankyrin and regulates axon growth, but it has not been studied for a role in retinotopic mapping. During development of retino-collicular topography, NrCAM was expressed uniformly in retinal ganglion cells (RGCs) along both mediolateral and anteroposterior retinal axes, and was localized on RGC axons within the optic tract and superior colliculus (SC). Anterograde tracing of RGC axons in NrCAM null mutant mice at P10, when the map resembles its mature form, revealed laterally displaced ectopic termination zones (eTZs) of axons from the temporal retina, indicating defective mediolateral topography, which is governed by ephrinB/EphBs. Axon tracing at P2 revealed that interstitial branch orientation of ventral-temporal RGC axons in NrCAM null mice was compromised in the medial direction, likely accounting for displacement of eTZs. A similar retinocollicular targeting defect in EphB mutant mice suggested that NrCAM and EphB interact to regulate mediolateral retino-collicular targeting. We found that EphB2 tyrosine kinase but not an EphB2 kinase dead mutant, phosphorylated NrCAM at a conserved tyrosine residue in the FIGQY ankyrin binding motif, perturbing ankyrin recruitment in NrCAM transfected HEK293 cells. Furthermore, the phosphorylation of NrCAM at FIGQY in SC was decreased in EphB1/3 and EphB1/2/3 null mice compared to WT, while phospho-FIGQY of NrCAM in SC was increased in EphB2 constitutively active (F620D/F620D) mice. These results demonstrate that NrCAM contributes to mediolateral retinocollicular axon targeting by regulating RGC branch orientation through a likely mechanism in which ephrinB/EphB phosphorylates NrCAM to modulate linkage to the actin cytoskeleton.
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Affiliation(s)
- Jinxia Dai
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Mona Buhusi
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Galina P. Demyanenko
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Leann H. Brennaman
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
| | - Martin Hruska
- Thomas Jefferson University, Department of Neuroscience, Jefferson Hospital for Neuroscience, Philadelphia, Pennsylvania, United States of America
| | - Matthew B. Dalva
- Thomas Jefferson University, Department of Neuroscience, Jefferson Hospital for Neuroscience, Philadelphia, Pennsylvania, United States of America
| | - Patricia F. Maness
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina, United States of America
- * E-mail:
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Cang J, Feldheim DA. Developmental mechanisms of topographic map formation and alignment. Annu Rev Neurosci 2013; 36:51-77. [PMID: 23642132 DOI: 10.1146/annurev-neuro-062012-170341] [Citation(s) in RCA: 163] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Brain connections are organized into topographic maps that are precisely aligned both within and across modalities. This alignment facilitates coherent integration of different categories of sensory inputs and allows for proper sensorimotor transformations. Topographic maps are established and aligned by multistep processes during development, including interactions of molecular guidance cues expressed in gradients; spontaneous activity-dependent axonal and dendritic remodeling; and sensory-evoked plasticity driven by experience. By focusing on the superior colliculus, a major site of topographic map alignment for different sensory modalities, this review summarizes current understanding of topographic map development in the mammalian visual system and highlights recent advances in map alignment studies. A major goal looking forward is to reveal the molecular and synaptic mechanisms underlying map alignment and to understand the physiological and behavioral consequences when these mechanisms are disrupted at various scales.
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Affiliation(s)
- Jianhua Cang
- Department of Neurobiology, Northwestern University, Evanston, IL 60208, USA.
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Ten-m3 is required for the development of topography in the ipsilateral retinocollicular pathway. PLoS One 2012; 7:e43083. [PMID: 23028443 PMCID: PMC3446960 DOI: 10.1371/journal.pone.0043083] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 07/16/2012] [Indexed: 11/20/2022] Open
Abstract
Background The alignment of ipsilaterally and contralaterally projecting retinal axons that view the same part of visual space is fundamental to binocular vision. While much progress has been made regarding the mechanisms which regulate contralateral topography, very little is known of the mechanisms which regulate the mapping of ipsilateral axons such that they align with their contralateral counterparts. Results Using the advantageous model provided by the mouse retinocollicular pathway, we have performed anterograde tracing experiments which demonstrate that ipsilateral retinal axons begin to form terminal zones (TZs) in the superior colliculus (SC), within the first few postnatal days. These appear mature by postnatal day 11. Importantly, TZs formed by ipsilaterally-projecting retinal axons are spatially offset from those of contralaterally-projecting axons arising from the same retinotopic location from the outset. This pattern is consistent with that required for adult visuotopy. We further demonstrate that a member of the Ten-m/Odz/Teneurin family of homophilic transmembrane glycoproteins, Ten-m3, is an essential regulator of ipsilateral retinocollicular topography. Ten-m3 mRNA is expressed in a high-medial to low-lateral gradient in the developing SC. This corresponds topographically with its high-ventral to low-dorsal retinal gradient. In Ten-m3 knockout mice, contralateral ventrotemporal axons appropriately target rostromedial SC, whereas ipsilateral axons exhibit dramatic targeting errors along both the mediolateral and rostrocaudal axes of the SC, with a caudal shift of the primary TZ, as well as the formation of secondary, caudolaterally displaced TZs. In addition to these dramatic ipsilateral-specific mapping errors, both contralateral and ipsilateral retinocollicular TZs exhibit more subtle changes in morphology. Conclusions We conclude that important aspects of adult visuotopy are established via the differential sensitivity of ipsilateral and contralateral axons to intrinsic guidance cues. Further, we show that Ten-m3 plays a critical role in this process and is particularly important for the mapping of the ipsilateral retinocollicular pathway.
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Andersson ER. The role of endocytosis in activating and regulating signal transduction. Cell Mol Life Sci 2012; 69:1755-71. [PMID: 22113372 PMCID: PMC11114983 DOI: 10.1007/s00018-011-0877-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 10/23/2011] [Accepted: 10/24/2011] [Indexed: 02/07/2023]
Abstract
Endocytosis is increasingly understood to play crucial roles in most signaling pathways, from determining which signaling components are activated, to how the signal is subsequently transduced and/or terminated. Whether a receptor-ligand complex is internalized via a clathrin-dependent or clathrin-independent endocytic route, and the complexes' subsequent trafficking through specific endocytic compartments, to then be recycled or degraded, has profound effects on signaling output. This review discusses the roles of endocytosis in three markedly different signaling pathways: the Wnt, Notch, and Eph/Ephrin pathways. These offer fundamentally different signaling systems: (1) diffusible ligands inducing signaling in one cell, (2) membrane-tethered ligands inducing signaling in a contacting receptor cell, and (3) bi-directional receptor-ligand signaling in two contacting cells. In each of these systems, endocytosis controls signaling in fascinating ways, and comparison of their similarities and dissimilarities will help to expand our understanding of endocytic control of signal transduction across multiple signaling pathways.
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Affiliation(s)
- Emma R Andersson
- Department of Cell and Molecular Biology, Karolinska Institute, 171 77, Stockholm, Sweden.
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Dai J, Dalal JS, Thakar S, Henkemeyer M, Lemmon VP, Harunaga JS, Schlatter MC, Buhusi M, Maness PF. EphB regulates L1 phosphorylation during retinocollicular mapping. Mol Cell Neurosci 2012; 50:201-10. [PMID: 22579729 DOI: 10.1016/j.mcn.2012.05.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 04/10/2012] [Accepted: 05/02/2012] [Indexed: 01/24/2023] Open
Abstract
Interaction of the cell adhesion molecule L1 with the cytoskeletal adaptor ankyrin is essential for topographic mapping of retinal ganglion cell (RGC) axons to synaptic targets in the superior colliculus (SC). Mice mutated in the L1 ankyrin-binding motif (FIGQY(1229)H) display abnormal mapping of RGC axons along the mediolateral axis of the SC, resembling mouse mutant phenotypes in EphB receptor tyrosine kinases. To investigate whether L1 functionally interacts with EphBs, we investigated the role of EphB kinases in phosphorylating L1 using a phospho-specific antibody to the tyrosine phosphorylated FIGQY(1229) motif. EphB2, but not an EphB2 kinase dead mutant, induced tyrosine phosphorylation of L1 at FIGQY(1229) and perturbed ankyrin recruitment to the membrane in L1-transfected HEK293 cells. Src family kinases mediated L1 phosphorylation at FIGQY(1229) by EphB2. Other EphB receptors that regulate medial-lateral retinocollicular mapping, EphB1 and EphB3, also mediated phosphorylation of L1 at FIGQY(1229). Tyrosine(1176) in the cytoplasmic domain of L1, which regulates AP2/clathrin-mediated endocytosis and axonal trafficking, was not phosphorylated by EphB2. Accordingly mutation of Tyr(1176) to Ala in L1-Y(1176)A knock-in mice resulted in normal retinocollicular mapping of ventral RGC axons. Immunostaining of the mouse SC during retinotopic mapping showed that L1 colocalized with phospho-FIGQY in RGC axons in retinorecipient layers. Immunoblotting of SC lysates confirmed that L1 was phosphorylated at FIGQY(1229) in wild type but not L1-FIGQY(1229)H (L1Y(1229)H) mutant SC, and that L1 phosphorylation was decreased in the EphB2/B3 mutant SC. Inhibition of ankyrin binding in L1Y(1229)H mutant RGCs resulted in increased neurite outgrowth compared to WT RGCs in retinal explant cultures, suggesting that L1-ankyrin binding serves to constrain RGC axon growth. These findings are consistent with a model in which EphB kinases phosphorylate L1 at FIGQY(1229) in retinal axons to modulate L1-ankyrin binding important for mediolateral retinocollicular topography.
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Affiliation(s)
- Jinxia Dai
- Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA
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Chenaux G, Henkemeyer M. Forward signaling by EphB1/EphB2 interacting with ephrin-B ligands at the optic chiasm is required to form the ipsilateral projection. Eur J Neurosci 2011; 34:1620-33. [PMID: 22103419 PMCID: PMC3228319 DOI: 10.1111/j.1460-9568.2011.07845.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
EphB receptor tyrosine kinases direct axonal pathfinding through interactions with ephrin-B proteins following axon-cell contact. As EphB:ephrin-B binding leads to bidirectional signals, the contributions of signaling into the Eph-expressing cell (forward signaling) or the ephrin-expressing cell (reverse signaling) cannot be assigned using traditional protein null alleles. To determine if EphB1 is functioning solely as a receptor during axon pathfinding, a new knock-in mutant mouse was created, EphB1(T-lacZ), which expresses an intracellular-truncated EphB1-β-gal fusion protein from the endogenous locus. As in the EphB1(-/-) protein null animals, the EphB1(T-lacZ/T-lacZ) homozygotes fail to form the ipsilateral projecting subpopulation of retinal ganglion cell axons. This indicates that reverse signaling through the extracellular domain of EphB1 is not required for proper axon pathfinding of retinal axons at the optic chiasm. Further analysis of other EphB and ephrin-B mutant mice shows that EphB1 is the preferred receptor of ephrin-B2 and, to a lesser degree, ephrin-B1 in mediating axon guidance at the optic chiasm despite the coexpression of EphB2 in the same ipsilaterally projecting retinal axons.
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Affiliation(s)
- George Chenaux
- Department of Developmental Biology and Kent Waldrep Foundation Center for Basic Research on Nerve Growth and Regeneration University of Texas Southwestern Medical Center 6000 Harry Hines Blvd. Dallas, TX 75390-9133, United States of America
| | - Mark Henkemeyer
- Department of Developmental Biology and Kent Waldrep Foundation Center for Basic Research on Nerve Growth and Regeneration University of Texas Southwestern Medical Center 6000 Harry Hines Blvd. Dallas, TX 75390-9133, United States of America
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Xu NJ, Henkemeyer M. Ephrin reverse signaling in axon guidance and synaptogenesis. Semin Cell Dev Biol 2011; 23:58-64. [PMID: 22044884 DOI: 10.1016/j.semcdb.2011.10.024] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 10/17/2011] [Indexed: 01/17/2023]
Abstract
Axon-cell and axon-dendrite contact is a highly regulated process necessary for the formation of precise neural circuits and a functional neural network. Eph-ephrin interacting molecules on the membranes of axon nerve terminals and target dendrites act as bidirectional ligands/receptors to transduce signals into both the Eph-expressing and ephrin-expressing cells to regulate cytoskeletal dynamics. In particular, recent evidence indicates that ephrin reverse signal transduction events are important in controlling both axonal and dendritic elaborations of neurons in the developing nervous system. Here we review how ephrin reverse signals are transduced into neurons to control maturation of axonal pre-synaptic and dendritic post-synaptic structures.
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Affiliation(s)
- Nan-Jie Xu
- Department of Developmental Biology, 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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A dual shaping mechanism for postsynaptic ephrin-B3 as a receptor that sculpts dendrites and synapses. Nat Neurosci 2011; 14:1421-9. [PMID: 21964490 PMCID: PMC3203317 DOI: 10.1038/nn.2931] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Accepted: 08/17/2011] [Indexed: 12/15/2022]
Abstract
As the neural network becomes wired, postsynaptic signaling molecules are thought to control the growth of dendrites and synapses. However, how these molecules are coordinated to sculpt postsynaptic structures is less well understood. We find that ephrin-B3, a transmembrane ligand for Eph receptors, functions postsynaptically as a receptor to transduce reverse signals into developing dendrites of mouse hippocampal neurons. Both tyrosine phosphorylation-dependent GRB4 SH2/SH3 adaptor-mediated signals and PSD-95-discs large-zona occludens-1 (PDZ) domain-dependent signals are required for inhibition of dendrite branching, whereas only PDZ interactions are necessary for spine formation and excitatory synaptic function. PICK1 and syntenin, two PDZ domain proteins, participate with ephrin-B3 in these postsynaptic activities. PICK1 has a specific role in spine and synapse formation, and syntenin promotes both dendrite pruning and synapse formation to build postsynaptic structures that are essential for neural circuits. The study thus dissects ephrin-B reverse signaling into three distinct intracellular pathways and protein-protein interactions that mediate the maturation of postsynaptic neurons.
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