Glial cell line-derived neurotrophic factor (GDNF) promotes axon outgrowth of dorsal root ganglia (DRG) neurons supplying porcine urinary bladder – an in vitro study

GDNF (glial cell-line-derived neurotrophic factor), and the closely related cytokines artemin and neurturin, bind strongly to heparin. Deletion of a basic amino-acid-rich sequence of 16 residues N-terminal to the first cysteine of the transforming growth factor β domain of GDNF results in a marked reduction in heparin binding, whereas removal of a neighbouring sequence, and replacement of pairs of other basic residues with alanine had no effect. The heparin-binding sequence is quite distinct from the binding site for the high affinity GDNF polypeptide receptor, GFRα1 (GDNF family receptor α1), and heparin-bound GDNF is able to bind GFRα1 simultaneously. The heparin-binding sequence of GDNF is dispensable both for GFRα1 binding, and for activity for in vitro neurite outgrowth assay. Surprisingly, the observed inhibition of GDNF bioactivity with the wild-type protein in this assay was still found with the deletion mutant lacking the heparin-binding sequence. Heparin neither inhibits nor potentiates GDNF–GFRα1 interaction, and the extracellular domain of GFRα1 does not bind to heparin itself, precluding heparin cross-bridging of cytokine and receptor polypeptides. The role of heparin and heparan sulfate in GDNF signalling remains unclear, but the present study indicates that it does not occur in the first step of the pathway, namely GDNF–GFRα1 engagement.

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Neuronal intermediate filament expression in rat dorsal root ganglia sensory neurons: An in vivo and in vitro study

Neuroscience ◽

10.1016/j.neuroscience.2008.02.080 ◽

2008 ◽

Vol 153 (4) ◽

pp. 1153-1163 ◽

Cited By ~ 42

Author(s):

M. Fornaro ◽

J.M. Lee ◽

S. Raimondo ◽

S. Nicolino ◽

S. Geuna ◽

...

Keyword(s):

Sensory Neurons ◽

Dorsal Root Ganglia ◽

Intermediate Filament ◽

Dorsal Root ◽

In Vitro Study ◽

Vitro Study

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In Vitro Gene Transfer into Mouse Spermatogonial Stem Cells on a Transgenic STO Feeder Layer Expressing Mouse Glial Cell Line-Derived Neurotrophic Factor.

Biology of Reproduction ◽

10.1093/biolreprod/81.s1.663 ◽

2009 ◽

Vol 81 (Suppl_1) ◽

pp. 663-663

Author(s):

Xueming X. Zhang ◽

Zhan-Peng Yue ◽

Ziyi Li ◽

De-xue Li ◽

Bo Tang

Keyword(s):

Stem Cells ◽

Gene Transfer ◽

Cell Line ◽

Glial Cell ◽

Neurotrophic Factor ◽

Spermatogonial Stem Cells ◽

Feeder Layer

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Intraspinal Implants of Fibrin Glue Containing Glial Cell Line-Derived Neurotrophic Factor Promote Dorsal Root Regeneration into Spinal Cord

Neurorehabilitation and Neural Repair ◽

10.1177/154596830101500304 ◽

2001 ◽

Vol 15 (3) ◽

pp. 173-182 ◽

Cited By ~ 16

Author(s):

Masaya Iwakawa ◽

Kazuo Mizoi ◽

Alan Tessler ◽

Yasunobu Itoh

Keyword(s):

Spinal Cord ◽

Horseradish Peroxidase ◽

Cell Line ◽

Glial Cell ◽

Fibrin Glue ◽

Neurotrophic Factor ◽

Dorsal Root ◽

Related Peptide ◽

Root Regeneration ◽

Calcitonin Gene

Objective: The purpose of this study was to determine whether glial cell line—de rived neurotrophic factor (GDNF) delivered intraspinally via a fibrin glue (FG) en hanced regeneration of cut dorsal root (DR). Methods: FG containing GDNF was inserted into aspiration cavities in the lumbar enlargement of adult rats. The tran sected L5 DR stump was placed at the bottom of the cavity and sandwiched between the FG and the spinal cord. Regenerated DR axons were labeled with horseradish peroxidase (HRP) or with immunohistochemical methods for calcitonin gene-related peptide (CGRP). Results: Primary afferent axons labeled with HRP regenerated into the spinal cord, received GDNF, and made frequent arborization there. Some of these were myelinated axons that established synapses on intraspinal neuronal profiles. CGRP-immunoreactive DR axons extended into the motor neurons and formed promi nent varicosities around their cell bodies. Only a few axons regenerated into the spinal cords given FG without GONE Conclusions: Our results indicate that GDNF en hances regeneration of DR into the adult rat spinal cord and that GDNF may be ef fectively supplied to the intraspinal injury site via FG. Because the regenerated axons establish synapses on intraspinal neurons, this therapeutic strategy has the potential to help to rebuild spinal reflex circuits interrupted by spinal cord injury. Key Words: GDNF—Fibrin glue—Intraspinal injury—Calcitonin gene-related peptide—Dorsal root regeneration—Electron microscopy—Glial cell line-derived neurotrophic fac tor—Horseradish peroxidase.

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