scholarly journals Growth cone collapse and inhibition of neurite growth by Botulinum neurotoxin C1: a t-SNARE is involved in axonal growth.

1996 ◽  
Vol 134 (1) ◽  
pp. 205-215 ◽  
Author(s):  
M Igarashi ◽  
S Kozaki ◽  
S Terakawa ◽  
S Kawano ◽  
C Ide ◽  
...  
Keyword(s):  
Growth Cone ◽  
Axonal Growth ◽  
Normal Growth ◽  
Neurite Growth ◽  
Total Surface Area ◽  
Central Domain ◽  
Growth Cone Collapse ◽  
Gradual Disappearance ◽  
Microscopic Studies ◽  
Presynaptic Protein

The growth cone is responsible for axonal growth, where membrane expansion is most likely to occur. Several recent reports have suggested that presynaptic proteins are involved in this process; however, the molecular mechanism details are unclear. We suggest that by cleaving a presynaptic protein syntaxin, which is essential in targeting synaptic vesicles as a target SNAP receptor (t-SNARE), neurotoxin C1 of Clostridium botulinum causes growth cone collapse and inhibits axonal growth. Video-enhanced microscopic studies showed (a) that neurotoxin C1 selectively blocked the activity of the central domain (the vesicle-rich region) at the initial stage, but not the lamellipodia in the growth cone; and (b) that large vacuole formation occurred probably through the fusion of smaller vesicles from the central domain to the most distal segments of the neurite. The total surface area of the accumulated vacuoles could explain the membrane expansion of normal neurite growth. The gradual disappearance of the surface labeling by FITC-WGA on the normal growth cone, suggesting membrane addition, was inhibited by neurotoxin C1. The experiments using the peptides derived from syntaxin, essential for interaction with VAMP or alpha-SNAP, supported the results using neurotoxin C1. Our results demonstrate that syntaxin is involved in axonal growth and indicate that syntaxin may participate directly in the membrane expansion that occurs in the central domain of the growth cone, probably through association with VAMP and SNAPs, in a SNARE-like way.

scholarly journals Plexin-B1/RhoGEF–mediated RhoA activation involves the receptor tyrosine kinase ErbB-2

2004 ◽  
Vol 165 (6) ◽  
pp. 869-880 ◽  
Author(s):  
Jakub M. Swiercz ◽  
Rohini Kuner ◽  
Stefan Offermanns
Keyword(s):  
Tyrosine Kinase ◽  
Growth Cone ◽  
Receptor Tyrosine Kinase ◽  
Hippocampal Neurons ◽  
Molecular Mechanisms ◽  
Axonal Growth ◽  
Dominant Negative ◽  
Growth Cone Collapse ◽  
Rhoa Activation ◽  
Axonal Growth Cone

Plexins are widely expressed transmembrane proteins that mediate the effects of semaphorins. The molecular mechanisms of plexin-mediated signal transduction are still rather unclear. Plexin-B1 has recently been shown to mediate activation of RhoA through a stable interaction with the Rho guanine nucleotide exchange factors PDZ-RhoGEF and LARG. However, it is unclear how the activity of plexin-B1 and its downstream effectors is regulated by its ligand Sema4D. Here, we show that plexin-B family members stably associate with the receptor tyrosine kinase ErbB-2. Binding of Sema4D to plexin-B1 stimulates the intrinsic tyrosine kinase activity of ErbB-2, resulting in the phosphorylation of both plexin-B1 and ErbB-2. A dominant-negative form of ErbB-2 blocks Sema4D-induced RhoA activation as well as axonal growth cone collapse in primary hippocampal neurons. Our data indicate that ErbB-2 is an important component of the plexin-B receptor system and that ErbB-2–mediated phosphorylation of plexin-B1 is critically involved in Sema4D-induced RhoA activation, which underlies cellular phenomena downstream of plexin-B1, including axonal growth cone collapse.

scholarly journals Unique Responses of Differentiating Neuronal Growth Cones to Inhibitory Cues Presented by Oligodendrocytes

1998 ◽  
Vol 142 (1) ◽  
pp. 191-202 ◽  
Author(s):  
A. Shibata ◽  
M.V. Wright ◽  
S. David ◽  
L. McKerracher ◽  
P.E. Braun ◽  
...  
Keyword(s):  
Growth Cone ◽  
Hippocampal Neurons ◽  
Dendritic Growth ◽  
System Development ◽  
Axonal Growth ◽  
Growth Cones ◽  
Nervous System Development ◽  
Environmental Cues ◽  
Growth Cone Collapse ◽  
Neuronal Growth Cones

During central nervous system development, neurons differentiate distinct axonal and dendritic processes whose outgrowth is influenced by environmental cues. Given the known intrinsic differences between axons and dendrites and that little is known about the response of dendrites to inhibitory cues, we tested the hypothesis that outgrowth of differentiating axons and dendrites of hippocampal neurons is differentially influenced by inhibitory environmental cues. A sensitive growth cone behavior assay was used to assess responses of differentiating axonal and dendritic growth cones to oligodendrocytes and oligodendrocyte- derived, myelin-associated glycoprotein (MAG). We report that >90% of axonal growth cones collapsed after contact with oligodendrocytes. None of the encounters between differentiating, MAP-2 positive dendritic growth cones and oligodendrocytes resulted in growth cone collapse. The insensitivity of differentiating dendritic growth cones appears to be acquired since they develop from minor processes whose growth cones are inhibited (nearly 70% collapse) by contact with oligodendrocytes. Recombinant MAG(rMAG)-coated beads caused collapse of 72% of axonal growth cones but only 29% of differentiating dendritic growth cones. Unlike their response to contact with oligodendrocytes, few growth cones of minor processes were inhibited by rMAG-coated beads (20% collapsed). These results reveal the capability of differentiating growth cones of the same neuron to partition the complex molecular terrain they navigate by generating unique responses to particular inhibitory environmental cues.

scholarly journals Vinaxanthone inhibits Semaphorin3A induced axonal growth cone collapse in embryonic neurons but fails to block its growth promoting effects on adult neurons

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Evguenia Ivakhnitskaia ◽  
Matthew R. Chin ◽  
Dionicio Siegel ◽  
Victor H. Guaiquil
Keyword(s):  
Nervous System ◽  
Growth Cone ◽  
Neuronal Cell ◽  
Neurite Growth ◽  
Cell Types ◽  
Pleiotropic Effect ◽  
In Vivo Models ◽  
Peripheral Neurons ◽  
Growth Cone Collapse

AbstractSemaphorin3A is considered a classical repellent molecule for developing neurons and a potent inhibitor of regeneration after nervous system trauma. Vinaxanthone and other Sema3A inhibitors are currently being tested as possible therapeutics to promote nervous system regeneration from injury. Our previous study on Sema3A demonstrated a switch in Sema3A’s function toward induction of nerve regeneration in adult murine corneas and in culture of adult peripheral neurons. The aim of the current study is to determine the direct effects of Vinaxanthone on the Sema3A induced adult neuronal growth. We first demonstrate that Vinaxanthone maintains its anti-Sema3A activity in embryonic dorsal root ganglia neurons by inhibiting Sema3A-induced growth cone collapse. However, at concentrations approximating its IC50 Vinaxanthone treatment does not significantly inhibit neurite formation of adult peripheral neurons induced by Sema3A treatment. Furthermore, Vinaxanthone has off target effects when used at concentrations above its IC50, and inhibits neurite growth of adult neurons treated with either Sema3A or NGF. Our results suggest that Vinaxanthone’s pro-regenerative effects seen in multiple in vivo models of neuronal injury in adult animals need further investigation due to the pleiotropic effect of Sema3A on various non-neuronal cell types and the possible effect of Vinaxanthone on other neuroregenerative signals.

scholarly journals hnRNP Q Regulates Internal Ribosome Entry Site-Mediated fmr1 Translation in Neurons

2018 ◽  
Vol 39 (4) ◽  
Author(s):  
Jung-Hyun Choi ◽  
Sung-Hoon Kim ◽  
Young-Hun Jeong ◽  
Sung Wook Kim ◽  
Kyung-Tai Min ◽  
...  
Keyword(s):  
Growth Cone ◽  
Internal Ribosome Entry Site ◽  
Rna Binding ◽  
Regulatory Mechanism ◽  
Fragile X ◽  
Axonal Growth ◽  
Entry Site ◽  
Internal Ribosome Entry ◽  
Growth Cone Collapse ◽  
Axonal Growth Cone

ABSTRACT Fragile X syndrome (FXS) caused by loss of fragile X mental retardation protein (FMRP), is the most common cause of inherited intellectual disability. Numerous studies show that FMRP is an RNA binding protein that regulates translation of its binding targets and plays key roles in neuronal functions. However, the regulatory mechanism for FMRP expression is incompletely understood. Conflicting results regarding internal ribosome entry site (IRES)-mediated fmr1 translation have been reported. Here, we unambiguously demonstrate that the fmr1 gene, which encodes FMRP, exploits both IRES-mediated translation and canonical cap-dependent translation. Furthermore, we find that heterogeneous nuclear ribonucleoprotein Q (hnRNP Q) acts as an IRES-transacting factor (ITAF) for IRES-mediated fmr1 translation in neurons. We also show that semaphorin 3A (Sema3A)-induced axonal growth cone collapse is due to upregulation of hnRNP Q and subsequent IRES-mediated expression of FMRP. These data elucidate the regulatory mechanism of FMRP expression and its role in axonal growth cone collapse.

Oligodendrocytes repel axons and cause axonal growth cone collapse

1989 ◽  
Vol 92 (1) ◽  
pp. 93-100 ◽  
Author(s):  
J.W. Fawcett ◽  
J. Rokos ◽  
I. Bakst
Keyword(s):  
Growth Cone ◽  
Dorsal Root ◽  
Axonal Growth ◽  
Time Lapse ◽  
Growth Cones ◽  
Newborn Rats ◽  
Growth Cone Collapse ◽  
Axonal Growth Cone ◽  
Video Studies ◽  
Culture Surface

We have examined the interactions between axons regenerating from dorsal root ganglia (DRGs) derived from newborn rats and oligodendrocytes cultured by three different techniques. Cultures examined after 2 days have a profuse outgrowth of axons from the DRGs, forming a dense mat on the culture surface. However, the axons avoid growing on oligodendrocytes; axons are seen all around these cells, but do not grow over them. We have also performed time-lapse video studies of the interactions between axonal growth cones and oligodendrocytes. Axons grow normally until their growth cone comes into direct contact with an oligodendrocyte, following which the growth cone remains motile for 30–60 min, but without making any progress over the cell. The growth cone then suddenly collapses, and the axon retracts, leaving a thin strand in contact with the cell. After this a new growth cone is usually elaborated and the process repeated. Oligodendrocytes are therefore inhibitory to axonal growth, and this may partially explain the failure of axons to regenerate in the mammalian central nervous system.

1224 A t-Snare is involved in axonal growth: Botulinum neurotoxin C1 induces growth cone collapse

1996 ◽  
Vol 25 ◽  
pp. S134 ◽  
Author(s):  
Michihiro Igarashi ◽  
Susumu Terakawa ◽  
Chizuka Ide ◽  
Yoshiaki Iomiya
Keyword(s):  
Growth Cone ◽  
Botulinum Neurotoxin ◽  
Axonal Growth ◽  
Growth Cone Collapse

Abstract WP141: Cyclic-AMP Induces Nogo-A Receptor NgR1 Internalization and Inhibits Nogo-A-Mediated Collapse of Growth Cone

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Rayudu Gopalakrishna ◽  
Angela Zhu ◽  
Andrew Oh ◽  
Julie Nguyen ◽  
Charlotte Lin ◽  
...  
Keyword(s):  
Cell Surface ◽  
Growth Cone ◽  
Axonal Regeneration ◽  
Axonal Growth ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Intracellular Camp ◽  
Growth Inhibitors ◽  
Intracellular Compartment ◽  
Growth Cone Collapse

Recovery of stroke and neuronal injuries requires the promotion of axonal regeneration from the remaining neurons. However, axonal regeneration is inhibited by diverse axonal growth inhibitors, such as Nogo-A. C-terminal domain of Nogo-A, Nogo-66 binds to the Nogo-A receptor 1 (NgR1) and induces the collapse of growth cones and inhibition of neurite outgrowth. NgR1 is also a receptor for additional axonal growth inhibitors. In this study, by using indirect immunofluorescence and biotinylation method, we have found that a cell-permeable cAMP analog (dibutyryl-cAMP) and other intracellular cAMP-elevating agents, such as forskolin, which directly activates adenylyl cyclase, and rolipram, which inhibits cyclic nucleotide phosphodiesterase, all induced rapid internalization of the cell surface NgR1 in Neuroscreen-1 (NS-1) cells. This endocytosis of NgR1 is lipid raft mediated. These cAMP-elevating agents induced a reversible distribution of NgR1 between the cell surface and intracellular compartment; NgR1 distributed to the cell surface at low levels of cAMP and distributed to an intracellular compartment at high levels of cAMP. Using pharmacological activators and inhibitors of protein kinase A (PKA) and the exchange protein directly activated by cAMP (Epac), we found that NgR1 internalization is independent of PKA but dependent on Epac. There is a correlation between the decrease in cell surface expression of NgR1 decreased sensitivity of NS-1 cells to Nogo-66-induced growth cone collapse. Therefore, besides axonal growth inhibitors affecting neurons, neurons by themselves self-regulate their own sensitivity to extracellular cues such as axonal growth inhibitors. This normal cellular regulatory mechanism may be therapeutically applied to overcome axonal growth inhibitors and enhance functional recovery after stroke and neuronal injuries.

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