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Carulli D, de Winter F, Verhaagen J. Semaphorins in Adult Nervous System Plasticity and Disease. Front Synaptic Neurosci 2021; 13:672891. [PMID: 34045951 PMCID: PMC8148045 DOI: 10.3389/fnsyn.2021.672891] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 04/12/2021] [Indexed: 12/13/2022] Open
Abstract
Semaphorins, originally discovered as guidance cues for developing axons, are involved in many processes that shape the nervous system during development, from neuronal proliferation and migration to neuritogenesis and synapse formation. Interestingly, the expression of many Semaphorins persists after development. For instance, Semaphorin 3A is a component of perineuronal nets, the extracellular matrix structures enwrapping certain types of neurons in the adult CNS, which contribute to the closure of the critical period for plasticity. Semaphorin 3G and 4C play a crucial role in the control of adult hippocampal connectivity and memory processes, and Semaphorin 5A and 7A regulate adult neurogenesis. This evidence points to a role of Semaphorins in the regulation of adult neuronal plasticity. In this review, we address the distribution of Semaphorins in the adult nervous system and we discuss their function in physiological and pathological processes.
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Affiliation(s)
- Daniela Carulli
- Laboratory for Neuroregeneration, Netherlands Institute for Neuroscience, Royal Academy of Arts and Sciences, Amsterdam, Netherlands
- Department of Neuroscience Rita Levi-Montalcini and Neuroscience Institute Cavalieri Ottolenghi, University of Turin, Turin, Italy
| | - Fred de Winter
- Laboratory for Neuroregeneration, Netherlands Institute for Neuroscience, Royal Academy of Arts and Sciences, Amsterdam, Netherlands
| | - Joost Verhaagen
- Laboratory for Neuroregeneration, Netherlands Institute for Neuroscience, Royal Academy of Arts and Sciences, Amsterdam, Netherlands
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Trans-Axonal Signaling in Neural Circuit Wiring. Int J Mol Sci 2020; 21:ijms21145170. [PMID: 32708320 PMCID: PMC7404203 DOI: 10.3390/ijms21145170] [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: 06/17/2020] [Revised: 07/15/2020] [Accepted: 07/17/2020] [Indexed: 12/24/2022] Open
Abstract
The development of neural circuits is a complex process that relies on the proper navigation of axons through their environment to their appropriate targets. While axon–environment and axon–target interactions have long been known as essential for circuit formation, communication between axons themselves has only more recently emerged as another crucial mechanism. Trans-axonal signaling governs many axonal behaviors, including fasciculation for proper guidance to targets, defasciculation for pathfinding at important choice points, repulsion along and within tracts for pre-target sorting and target selection, repulsion at the target for precise synaptic connectivity, and potentially selective degeneration for circuit refinement. This review outlines the recent advances in identifying the molecular mechanisms of trans-axonal signaling and discusses the role of axon–axon interactions during the different steps of neural circuit formation.
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Abstract
Semaphorins are extracellular signaling proteins that are essential for the development and maintenance of many organs and tissues. The more than 20-member semaphorin protein family includes secreted, transmembrane and cell surface-attached proteins with diverse structures, each characterized by a single cysteine-rich extracellular sema domain, the defining feature of the family. Early studies revealed that semaphorins function as axon guidance molecules, but it is now understood that semaphorins are key regulators of morphology and motility in many different cell types including those that make up the nervous, cardiovascular, immune, endocrine, hepatic, renal, reproductive, respiratory and musculoskeletal systems, as well as in cancer cells. Semaphorin signaling occurs predominantly through Plexin receptors and results in changes to the cytoskeletal and adhesive machinery that regulate cellular morphology. While much remains to be learned about the mechanisms underlying the effects of semaphorins, exciting work has begun to reveal how semaphorin signaling is fine-tuned through different receptor complexes and other mechanisms to achieve specific outcomes in various cellular contexts and physiological systems. These and future studies will lead to a more complete understanding of semaphorin-mediated development and to a greater understanding of how these proteins function in human disease.
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Affiliation(s)
- Laura Taylor Alto
- Departments of Neuroscience and Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Jonathan R Terman
- Departments of Neuroscience and Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
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Assens A, Dal Col JA, Njoku A, Dietschi Q, Kan C, Feinstein P, Carleton A, Rodriguez I. Alteration of Nrp1 signaling at different stages of olfactory neuron maturation promotes glomerular shifts along distinct axes in the olfactory bulb. Development 2016; 143:3817-3825. [PMID: 27578798 DOI: 10.1242/dev.138941] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 08/23/2016] [Indexed: 12/25/2022]
Abstract
Building the topographic map in the mammalian olfactory bulb is explained by a model based on two axes along which sensory neurons are guided: one dorsoventral and one anteroposterior. This latter axis relies on specific expression levels of Nrp1. To evaluate the role of this receptor in this process, we used an in vivo genetic approach to decrease or suppress Nrp1 in specific neuronal populations and at different time points during axonal targeting. We observed, in neurons that express the M71 or M72 odorant receptors, that Nrp1 inactivation leads to two distinct wiring alterations, depending on the time at which Nrp1 expression is altered: first, a surprising dorsal shift of the M71 and M72 glomeruli, which often fuse with their contralateral counterparts, and second the formation of anteriorized glomeruli. The two phenotypes are partly recapitulated in mice lacking the Nrp1 ligand Sema3A and in mice whose sensory neurons express an Nrp1 mutant unable to bind Sema3A. Using a mosaic conditional approach, we show that M71 axonal fibers can bypass the Nrp1 signals that define their target area, since they are hijacked and coalesce with Nrp1-deficient M71-expressing axons that target elsewhere. Together, these findings show drastically different axonal targeting outcomes dependent on the timing at which Nrp1/Sema3A signaling is altered.
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Affiliation(s)
- Alexis Assens
- Department of Genetics and Evolution, University of Geneva, Geneva 1205, Switzerland.,Geneva Neuroscience Center, University of Geneva, Geneva 1205, Switzerland
| | - Julien A Dal Col
- Department of Genetics and Evolution, University of Geneva, Geneva 1205, Switzerland.,Geneva Neuroscience Center, University of Geneva, Geneva 1205, Switzerland
| | - Anthony Njoku
- Department of Genetics and Evolution, University of Geneva, Geneva 1205, Switzerland.,Geneva Neuroscience Center, University of Geneva, Geneva 1205, Switzerland
| | - Quentin Dietschi
- Department of Genetics and Evolution, University of Geneva, Geneva 1205, Switzerland.,Geneva Neuroscience Center, University of Geneva, Geneva 1205, Switzerland
| | - Chenda Kan
- Department of Genetics and Evolution, University of Geneva, Geneva 1205, Switzerland.,Geneva Neuroscience Center, University of Geneva, Geneva 1205, Switzerland
| | - Paul Feinstein
- Department of Biological Sciences, Hunter College and The Graduate Center Biochemistry, Biology and Biopsychology and Behavioral Neuroscience Programs, CUNY, New York, NY10065, USA
| | - Alan Carleton
- Geneva Neuroscience Center, University of Geneva, Geneva 1205, Switzerland .,Department of Basic Neurosciences, School of Medicine, University of Geneva, Geneva 1205, Switzerland
| | - Ivan Rodriguez
- Department of Genetics and Evolution, University of Geneva, Geneva 1205, Switzerland .,Geneva Neuroscience Center, University of Geneva, Geneva 1205, Switzerland
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Faghihi F, Moustafa AA. Impaired homeostatic regulation of feedback inhibition associated with system deficiency to detect fluctuation in stimulus intensity: a simulation study. Neurocomputing 2015. [DOI: 10.1016/j.neucom.2014.11.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Suárez R, García-González D, de Castro F. Mutual influences between the main olfactory and vomeronasal systems in development and evolution. Front Neuroanat 2012; 6:50. [PMID: 23269914 PMCID: PMC3529325 DOI: 10.3389/fnana.2012.00050] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 11/26/2012] [Indexed: 12/14/2022] Open
Abstract
The sense of smell plays a crucial role in the sensory world of animals. Two chemosensory systems have been traditionally thought to play-independent roles in mammalian olfaction. According to this, the main olfactory system (MOS) specializes in the detection of environmental odorants, while the vomeronasal system (VNS) senses pheromones and semiochemicals produced by individuals of the same or different species. Although both systems differ in their anatomy and function, recent evidence suggests they act synergistically in the perception of scents. These interactions include similar responses to some ligands, overlap of telencephalic connections and mutual influences in the regulation of olfactory-guided behavior. In the present work, we propose the idea that the relationships between systems observed at the organismic level result from a constant interaction during development and reflects a common history of ecological adaptations in evolution. We review the literature to illustrate examples of developmental and evolutionary processes that evidence these interactions and propose that future research integrating both systems may shed new light on the mechanisms of olfaction.
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Affiliation(s)
- Rodrigo Suárez
- Queensland Brain Institute, The University of Queensland, St Lucia Brisbane, QLD, Australia ; Departamento de Biología, Facultad de Ciencias, Universidad de Chile Santiago, Chile
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