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. 2002 May 15;22(10):4057-65.
doi: 10.1523/JNEUROSCI.22-10-04057.2002.

Glial cell line-derived neurotrophic factor is a survival factor for isolectin B4-positive, but not vanilloid receptor 1-positive, neurons in the mouse

Melissa Zwick  1 , Brian M Davis, C Jeffrey Woodbury, John N Burkett, H Richard Koerber, James F Simpson, Kathryn M Albers
Affiliations

Glial cell line-derived neurotrophic factor is a survival factor for isolectin B4-positive, but not vanilloid receptor 1-positive, neurons in the mouse

Melissa Zwick et al. J Neurosci. .

Abstract

Most, if not all, nociceptor sensory neurons are dependent on nerve growth factor (NGF) during early embryonic development. A large subpopulation of these sensory neurons loses NGF dependency between embryonic day 16 and postnatal day 14 and become responsive to glial cell line-derived growth factor (GDNF), a member of the transforming growth factor beta (TGF-beta) family. To examine the survival and phenotypic effects of GDNF on sensory neurons in vivo, we generated transgenic mice that overexpress GDNF in the skin. GDNF-overexpresser mice had increased numbers of small unmyelinated sensory neurons that express the tyrosine kinase receptor Ret and bind the plant isolectin B4 (IB4). Surprisingly, in wild-type and transgenic mice, few ( approximately 2%) IB4-positive neurons expressed the vanilloid receptor VR1, a heat-sensitive receptor expressed by many IB4-positive neurons of the rat. Thus, in mouse, GDNF-dependent IB4-positive neurons must use a non-VR1 heat receptor. In addition, the behavior of GDNF-overexpresser animals to noxious heat or mechanical stimuli was indistinguishable from wild-type animals, indicating that, on a behavioral level, peripherally applied GDNF does not alter the sensitivity of the somatosensory system.

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Figures

Fig. 1.
Fig. 1.
Characterization of GDNF-overexpressing transgenic mice. a, Gene construct for GDNF transgene expression.Large arrow indicates transcription start site;small arrows mark PCR primer binding sites used to detect endogenous and transgene GDNF mRNAs. b, Reverse transcriptase-PCR analysis shows relative level of GDNF mRNA in transgenic lines (235, 097, 002, and324) relative to wild-type littermates. Shown are levels of total GDNF mRNA (endogenous and transgene derived), transgene-derived GDNF mRNA, and actin mRNA. c, ELISA measure of GDNF peptide in various tissues shows increased peptide in skin, ganglia, and spinal cord. d, Footpad skin immunolabeled with an antibody to PGP 9.5 shows skin of transgenic animals is hyperinnervated, particularly in lower epidermal layers (epi, epidermis; derm, dermis;nb, nerve bundle). Arrows indicate nerve fibers in epidermis. Scale bar, 50 μm.
Fig. 2.
Fig. 2.
Cytochemical analysis of mouse L4/L5 dorsal root ganglia. a, b, Sections of DRG immunolabeled with an HRP-conjugated IB4 lectin. IB4-binding neurons of GDNF-OE mice are larger. Counts of labeled and unlabeled neurons showed their percentage also increased (Table 1). c, d, The CGRP-immunopositive population in GDNF-OE mice was slightly larger compared with wild-type ganglia. e, f, Immunolabeling using avidin–biotin HRP detection showed no change in the size or percentage of VR1-positive neurons in transgenic ganglia. g, h, The size and number of P2X3-positive neurons increased in GDNF-OE mice, although the percentage was unchanged. See also Table 1. Scale bar, 50 μm.
Fig. 3.
Fig. 3.
The effect of GDNF overexpression on the size distribution of specific neuronal populations. a, The distribution of neuronal areas for IB4-positive neurons (n = 3 in each group), CGRP-positive neurons (n = 3 in each group) (b), P2X3-positive neurons (n = 4 in each group) (c), and VR1-positive neurons (n = 3 in each group) (d) in wild-type and transgenic ganglia. For each population examined, transgenic neurons (filled bars) are significantly larger relative to wild-type neurons (open bars) (p < 0.050; ttest).
Fig. 4.
Fig. 4.
Analysis of phenotypic overlap in mouse dorsal root ganglia. a, b, Sections of DRG labeled with IB4 (green) and CGRP (red) show little overlap (yellow) between the two populations in wild-type and transgenic sections. c, d, Similar to IB4/CGRP overlap, IB4-positive (green) and VR1-positive (red) neurons have little overlap in wild-type and transgenic animals. e, f, Unlike VR1 and CGRP, IB4-positive (green) and P2X3-positive (red) neurons overlap almost completely. See also Table 2. Scale bar, 100 μm.
Fig. 5.
Fig. 5.
Overexpression of GDNF increases axon number and size in the saphenous nerve. a, Cross-section of representative sections from the saphenous nerve of GDNF-OE (left; 29,503 ± 1555 mm2) and age-matched wild-type mice (right; 14,691 ± 881 mm2). Nerve diameter was approximately double in transgenic mice. For each group, n = 3;p < 0.001; t test. Scale bar, 50 μm. b, d, Distribution of myelinated and unmyelinated axons in the saphenous nerve of wild-type (open bars) and GDNF-OE mice (filled bars). For each group,n = 3. Myelinated axon diameter includes the nerve axon only, without the myelin sheath. Note both axon distributions in GDNF-OE animals are shifted to the right, reflecting hypertrophy of myelinated and unmyelinated fibers (p < 0.050; t-test). c, Regression analysis of myelin thickness versus axon diameter for wild-type (open circles, dashed line) and GDNF-OE mice (filled circles, continuous line). For each group,n = 3. A significant linear correlation was calculated for both genotypes (wild-type,r2 = 0.53; p< 0.001; GDNF-OE, r2 = 0.79;p < 0.001), although GDNF-OE axons had thinner myelin for a given axonal diameter (p < 0.050; ANCOVA).
Fig. 6.
Fig. 6.
GDNF overexpression in skin increases primary afferent density in the spinal cord dorsal horn. a, b, The band of IB4 (green) labeling in the dorsal horn is broader and overlaps more superficially with the band of CGRP (red) labeling in GDNF-OE animals compared with wild-type animals. c, d, The band of VR1 (red) labeling shows no overlap with the band of IB4 (green) labeling and is unchanged in GDNF-OE mice. Scale bar, 100 μm.
Fig. 7.
Fig. 7.
The GDNF-mediated enhancements of the sensory system do not affect thermal or mechanical behavioral sensitivity.a, Transgenic and wild-type animals were tested for changes in thermal sensitivity by exposing them to a hot plate set at 52.0 ± 0.2°C, a radiant heat source applied to the tail (tail flick), and radiant heat applied to the foot (Hargreaves' assay). No significant difference was measured between the behavior of transgenic and wild-type mice (n = 10 in each group).b, Cumulative sum distribution of mechanical thresholds to von Frey filament stimulation in wild-type (open circles) and GDNF-OE (filled circles) mice (n = 10 in each group). No significant change in behavioral response was measured.
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References

    1. Albers KM, Wright DE, Davis BM. Overexpression of nerve growth factor in epidermis of transgenic mice causes hypertrophy of the peripheral nervous system. J Neurosci. 1994;14:1422–1432. - PMC - PubMed
    1. Albers KM, Perrone TN, Goodness TP, Jones ME, Green MA, Davis BM. Cutaneous overexpression of NT-3 increases sensory and sympathetic neuron number and enhances touch dome and hair follicle innervation. J Cell Biol. 1996;134:487–497. - PMC - PubMed
    1. Averill S, McMahon SB, Clary DO, Reichardt LF, Priestley JV. Immunocytochemical localization of trkA receptors in chemically identified subgroups of adult rat sensory neurons. Eur J Neurosci. 1995;7:1484–1494. - PMC - PubMed
    1. Baloh RH, Tansey MG, Golden JP, Creedon DJ, Heuckeroth RO, Keck CL, Zimonjic DB, Popescu NC, Johnson EM, Milbrandt J., Jr TrnR2, a novel receptor that mediates neurturin and GDNF signaling through Ret. Neuron. 1997;18:793–802. - PubMed
    1. Baloh RH, Tansey MG, Lampe PA, Fahrner TJ, Enomoto H, Simburger KS, Leitner ML, Araki T, Johnson EM, Milbrandt J., Jr Artemin, a novel member of the GDNF ligand family, supports peripheral and central neurons and signals through the GFRalpha3-RET receptor complex. Neuron. 1998;21:1291–1302. - PubMed

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