Chapter category: Neuroscience
Neuropilin and Class 3 Semaphorins in Nervous System Regeneration
Neuropilin: From Nervous System
to Vascular and Tumor Biology
Edited by: Dominique BagnardISBN: 0-306-47416-6
» Get more information about this book at landesbioscience.com «
Chapter authors:
Fred De Winter, Anthony J.G.D. Holtmaat and Joost Verhaagen
Injury to the mature mammalian central nervous system (CNS) is often accompanied by permanent loss of function of the damaged neural circuits. The failure of injured CNS axons to regenerate is thought to be caused, in part, by neurite outgrowth inhibitory factors expressed in and around the lesion. These include several myelin associated inhibitors, proteoglycans, and tenascin-R. Recent studies have documented the presence of class 3 semaphorins in fibroblast-like meningeal cells present in the core of the neural scar formed following CNS injury. Class 3 semaphorins display neurite growth-inhibitory effects on growing axons during embryonic development. The induction of the expression of class 3 semaphorins in the neural scar and the persistent expression of their receptors, the neuropilins and plexins, by injured CNS neurons suggest that they contribute to the regenerative failure of CNS neurons. Neuropilins are also expressed in the neural scar in a subpopulation of meningeal fibroblast and in neurons in the vicinity of the scar. Semaphorin/neuropilin signaling might therefore also be important for cell migration, angiogenis and neuronal cell death in or around neural scars.
In contrast to neurons in the CNS, neuropilin/plexin positive neurons in the PNS do display long distance regeneration following injury. Injured PNS neurons do not encounter a semaphorin positive neural scar. Furthermore, Semaphorin 3A is downregulated in the regenerating spinal motor neurons themselves. This was accompanied by a transient upregulation of Semaphorin 3A in the target muscle. These observations suggest that the injury induced regulation of Semaphorin 3A in the PNS contributes to successful regeneration and target reinnervation. Future studies in genetically modified mice should provide more insight into the mechanisms by which neuropilins and semaphorins influence nervous system regeneration and degeneration.
Additional chapters from this book:
Neuropilin and Class 3 Semaphorins in Nervous System Regeneration
Fred De Winter, Anthony J.G.D. Holtmaat and Joost Verhaagen
Injury to the mature mammalian central nervous system (CNS) is often accompanied by permanent loss of function of the damaged neural circuits. The failure of injured CNS axons to regenerate...
Neuropilin and its Ligands in Normal Lung and Cancer
Joëlle Roche, Harry Drabkin and Elisabeth Brambilla
Neuropilins (NRPs) are receptors for class 3 Semaphorins and function as co-receptors for Vascular endothelial growth factor isoforms, VEGF165 and VEGF145 and related mol...
The Function of Neuropilin / L1 Complex
V. Castellani
L1, a cell adhesion molecule of the Ig superfamily (IgCAM) plays a critical role in the formation of neuronal networks. This is reflected by the variety of clinical signs associated with the X...
The Interaction of Neuropilin-1 and Neuropilin-2 with Tyrosine-Kinase Receptors or VEGF
Gera Neufeld, Ofra Kessler and Yael Herzog
The Neuropilin-1 (NRP1) and Neuropilin-2 (NRP2) receptors were initially described as receptors for axon guidance factors belonging to the class-3 Semaphorin sub-family. Subsequently, it wa...
The Function of Neuropilin/Plexin Complexes
Andreas W. Püschel
Neuropilins bind the secreted class 3 semaphorins with high affinity but require a member of the plexin family to form receptors that are able to activate downstream signal transduction cascad...
Structural and Functional Relation of Neuropilins
Fumio Nakamura and Yoshio Goshima
Neuropilin is a type I transmembrane protein and the molecular mass is 120 kDa. Two homologues, Neuropilin-1 and -2, are identified. The primary structure of Neuropilin-1 and Neuropilin-2 is w...
Neuropilin-1 in the Immune System
Paul-Henri Romeo, Valérie Lemarchandel and Rafaele Tordjman
The neuropilin-1 (NRP1) and neuropilin-2 (NRP2) receptors can bind the class-3 semaphorin subfamily and the heparin-binding forms of vascular endothelial growth factor (VEGF) and placenta grow...
The Role of Neuropilin in Vascular and Tumor Biology
Michael Klagsbrun, Seiji Takashima and Roni Mamluk
Neuropilin1 (NRP1) and NRP2 are related transmembrane receptors that function as mediators of neuronal guidance and angiogenesis. NRPs bind members of the class 3 semaphorin family, regulators...
Neuropilins as Semaphorin Receptors: In vivo Functions in Neuronal Cell
Anil Bagri and Marc Tessier-Lavigne
After the initial discovery of neuropilin-1 as an epitope on axons recognized by a monoclonal antibody, neuropilins were rediscovered in the search for receptors mediating the repulsive action...
From the Discovery of Neuropilin to the Determination of its Adhesion Sites
Hajime Fujisawa
Neuropilin (NRP) and plexin (Plex) that are now known to be semaphorin receptors were initially identified as antigens for monoclonal antibodies (MAbs) that bound to particular neuropiles and ...
