Glial Cell Line-derived Neurotrophic Factor Group Research Articles

Retracted: The effects of exogenous human glial cell line-derived neurotrophic factor on functional regeneration of severed femoral nerve and its underlying mechanisms.

Femoral nerve injury remains a significant challenge in clinical practice due to the lack of effective treatment strategies. In the present study, we established a new drug delivery system consisting of a polylactic acid-trimethylene carbonate (PA-TC) tube loaded with glial cell line-derived neurotrophic factor (GDNF) and tested its efficacy to promote functional recovery of femoral nerve after injuries. GDNF was injected into the tube that was fitted to the ends of the transected femoral nerve in rats. Functional recovery was assessed at 4, 8, and 12 weeks after the injury. The results demonstrated that the rats treated with the PA-TC tube loaded with GDNF showed significantly improved recovery in muscle action potentials and regenerated fiber area compared with animals treated by autologous nerve grafting (ANG) (all P < 0.05). In addition, the cross-sectional area of myelinated nerve fiber was higher in the PA-TC+GDNF group than in the ANG group at 8 and 12 weeks. The hindlimb grip strength and recovery rate were higher in the PA-TC+GDNF group than those in the ANG group at 8 and 12 weeks. These results demonstrated that our drug delivery system induced nerve regeneration and functional recovery after femoral nerve transection that was superior to that induced by ANG. It may have potential applications in nerve regeneration of peripheral nerve transection injuries.

Comparative Analysis of the Effects of Neurotrophic Factors CDNF and GDNF in a Nonhuman Primate Model of Parkinson's Disease.

Cerebral dopamine neurotrophic factor (CDNF) belongs to a newly discovered family of evolutionarily conserved neurotrophic factors. We demonstrate for the first time a therapeutic effect of CDNF in a unilateral 6-hydroxydopamine (6-OHDA) lesion model of Parkinson’s disease in marmoset monkeys. Furthermore, we tested the impact of high chronic doses of human recombinant CDNF on unlesioned monkeys and analyzed the amino acid sequence of marmoset CDNF. The severity of 6-OHDA lesions and treatment effects were monitored in vivo using 123I-FP-CIT (DaTSCAN) SPECT. Quantitative analysis of 123I-FP-CIT SPECT showed a significant increase of dopamine transporter binding activity in lesioned animals treated with CDNF. Glial cell line-derived neurotrophic factor (GDNF), a well-characterized and potent neurotrophic factor for dopamine neurons, served as a control in a parallel comparison with CDNF. By contrast with CDNF, only single animals responded to the treatment with GDNF, but no statistical difference was observed in the GDNF group. However, increased numbers of tyrosine hydroxylase immunoreactive neurons, observed within the lesioned caudate nucleus of GDNF-treated animals, indicate a strong bioactive potential of GDNF.

Glial cell line-derived neurotrophic factor induced the differentiation of amniotic fluid-derived stem cells into vascular endothelial-like cells in vitro

Amniotic fluid-derived stem cells (AFSCs) are a novel source of stem cells that are isolated and cultured from second trimester amniocentesis. Glial cell line-derived neurotrophic factor (GDNF) acts as a tissue morphogen and regulates stem cell proliferation and differentiation. This study investigated the effect of an adenovirus-mediated GDNF gene, which was engineered into AFSCs, on the cells' biological properties and whether GDNF in combination with AFSCs can be directionally differentiated into vascular endothelial-like cells in vitro. AFSCs were isolated and cultured using the plastic adherence method in vitro and identified by the transcription factor Oct-4, which is the primary marker of pluripotent stem cells. AFSCs were efficiently transfected by a GFP-labeled plasmid system of an adenovirus vector carrying the GDNF gene (Ad-GDNF-GFP). Transfected AFSCs stably expressed GDNF. Transfected AFSCs were cultured in endothelial growth medium-2 containing vascular endothelial growth factor. After 1 week, AFSCs were positive for von Willebrand factor (vWF) and CD31, which are markers of endothelial cells, and the recombinant GDNF group was significantly higher than undifferentiated controls and the GFP only group. These results demonstrated that AFSCs differentiated into vascular endothelial-like cells in vitro, and recombinant GDNF promoted differentiation. The differentiation-induced AFSCs may be used as seed cells to provide a new manner of cell and gene therapies for transplantation into the vascular injury site to promote angiogenesis.

English

The aim of this study was to investigate the efficiency of intrathecal glial cell line-derived neurotrophic factor (GDNF) on nitric oxide (NO) and nitric oxide synthase (NOS) activity following a spinal nerve ligation (SNL) of male Sprague Dawley rats. The rats were randomly divided into four groups: normal (control), sham-operated, SNL (SNL followed by a physiological saline injection into the subarachnoid space), and GDNF (SNL followed by a GDNF injection into the subarachnoid space). Each group was divided into three subgroups (n = 10). The rats in each subgroup were euthanised 3, 7, and 14&nbsp;days after the operation. Rat behaviour was evaluated before euthanising, and the ipsilateral spinal cords were harvested after euthanising to determine the NO content and NOS activity. Compared with the control and sham-operated groups, the NO content and NOS activity in the SNL group increased significantly 3&nbsp;days after the operation; this increase was maintained until 14&nbsp;days after the operation (P&nbsp;&lt; 0.01 or 0.05). A significant decrease was observed in the NO content and NOS activity in the GDNF group compared with the SNL group. The decrease continued until 14&nbsp;days after the operation (P&nbsp;&lt; 0.01 or 0.05). The results indicated that the NO and NOS activity in the rat spinal cord are associated with SNL-induced neuropathic pain. The decreased neuropathic pain from the intrathecal GDNF is correlated with the decrease in NO content and NOS activity in the spinal cord. &nbsp; Key words:&nbsp;Glial cell line-derived neurotrophic factor, neuralgia, nitric oxide, nitric oxide synthase.

Sympathetic Innervation Induced in Engrafted Engineered Cardiomyocyte Sheets by Glial Cell Line Derived Neurotrophic FactorIn Vivo

The aim of myocardial tissue engineering is to repair or regenerate damaged myocardium with engineered cardiac tissue. However, this strategy has been hampered by lack of functional integration of grafts with native myocardium. Autonomic innervation may be crucial for grafts to function properly with host myocardium. In this study, we explored the feasibility of in vivo induction of autonomic innervation to engineered myocardial tissue using genetic modulation by adenovirus encoding glial cell line derived neurotrophic factor (GDNF). GFP-transgene (control group) or GDNF overexpressing (GDNF group) engineered cardiomyocyte sheets were transplanted on cryoinjured hearts in rats. Nerve fibers in the grafts were examined by immunohistochemistry at 1, 2, and 4 weeks postoperatively. Growth associated protein-43 positive growing nerves and tyrosine hydroxylase positive sympathetic nerves were first detected in the grafts at 2 weeks postoperatively in control group and 1 week in GDNF group. The densities of growing nerve and sympathetic nerve in grafts were significantly increased in GDNF group. No choline acetyltransferase immunopositive parasympathetic nerves were observed in grafts. In conclusion, sympathetic innervation could be effectively induced into engrafted engineered cardiomyocyte sheets using GDNF.

Effects of Glial Cell Line-Derived Neurotrophic Factor Intrathecal Injection on Spinal Dorsal Horn Glial Fibrillary Acidic Protein Expression in a Rat Model of Neuropathic Pain

ABSTRACTGlial fibrillary acidic protein (GFAP) is a specific astrocytic marker in the central nervous system. Few studies on the effects of glial cell line-derived neurotrophic factor (GDNF) intrathecal injection on GFAP expression exist in the literature. The present study determined GFAP expression in rat spinal dorsal horn following a spinal nerve ligation (SNL). The effects of GDNF intrathecal injection on GFAP expression were examined to gather experimental evidence on the mechanisms underlying neuropathic pain. Following L5–6 SNL, male Sprague-Dawley rats were randomly divided into four groups: normal control, sham-operated, SNL, and GDNF. Each group was further divided into three subgroups (n = 10) according to the times of sacrifice: 3, 7, and 14 days after surgery. Compared with the normal control and the sham-operated groups, GFAP expression in the SNL group increased at day 3 after surgery and lasted until 14 days after. GFAP expression was significantly less in the GDNF group compared with the SNL group which lasted until 14 days after surgery, suggesting that rat spinal dorsal horn GFAP expression contributes to SNL-induced neuropathic pain. The mechanisms underlying GDNF alleviation of neuropathic pain were shown to be related to the GDNF inhibition of GFAP expression in the spinal dorsal horn.

Repair of sciatic nerve defect with implantation of glial cell line-derived neurotrophic factor locally secreting mesenchymal stem cells in rabbits

Objective To investigate the repairative effect of local high expression of glial cell line-derived neurotrophic factor （GDNF） in the repair of sciatic nerve defects. Green fluorescent protein （GFP） gene was used as reporter gene. Two groups including gel matrix control group and gel matrix plus MSCs group were set （ 10 rabbits per group）. Methods GDNF secreting mesenchymal stem cells （MSCs） mediated by lentiviral vectors were suspended in Matrigel to produce the artificial graft, and then it was locally implanted to a 20 mm-long sciatic nerve defect in rabbits. Results In the GDNF group,the nerve continuity was restored in seven rabbits and the functional amelioration of the wounded limb was apparent. While there found no restoration of the nerve continuity in the control groups. The migration distance of GDNF secreting MSCs was 20 mm, suggesting a good integration of the transplanted cells with host cells. The glial fibrillary acidic protein （GFAP） ＋ green fluorescent protein （GFP） and -100 protein GFP accounted for 60% and 70% respectively in the experimental group, while it was only 40% and 30% in gel matrix plus MSCs group. Conclusions Local implantation of GDNF secreting MSCs can promote the regeneration and functional recovery of the sciatic nerves. GDNF seems to play an important role in inducing transdifferentiation of MSCs to Schwann cell lineage. Key words: Sciatic nerve; Mesenchymal stem cells; Glial cell line-derived neurotrophic factor

Effects of glial cell line-derived neurotrophic factor on the proliferation and differentiation of PLZF and c-Kit of spermatogonial stem cells of rats in vitro

Objective To investigate the effects of glial cell line-derived neurotrophic factor(GDNF)on the gene transcriptions and expressions of promyelocytic leukaemia zinc finger(PLZF)and c-Kit in spermatogonial stem cells(SSC).Methods SSC was cultured in DMEM plus different concentrations of GDNF(0,10,50,100 ng/ml).Quantitative reverse transcription PCR was used to detect the mRNA of PLZF and c-Kit.The expressions of PLZF and c-Kit protein were detected by Western blot assay.Results With the control group and 10ng/ml of GDNF group cell growth has no obvious influence,but with 50 ng/ml of GDNF group and 100 ng/ml of GDNF group cell growth was enhanced significantly.In the control group,the PLZF mRNA was 0.28±0.13 and c-Kit mRNA was 0.65±0.21.In the 10 ng/ml of GDNF group,PLZF mRNA was 0.27±0.14 and c-Kit tuRNA was 0.62±0.19.Compared with the control group,10 ng/ml of GDNF group had not influence on PLZF and c-Kit mRNA.In the 50 ng/ml of GDNF group PLZF mRNA was 0.64±0.28 and c-Kit mRNA was 0.34±0.15.Compared with the control group,50 ng/ml of GDNF enhanced the transcription of PLZF mRNA(P＜0.05),decreased the transeription of c-Kit mRNA (P＜0.05).In the 100 ng/ml of GDNF gmup,PLZF mRNA was 0.68±0.27 and c-Kit mRNA was 0.28±0.18.In the 100 ng/ml of GDNF group,there was no difference compared with 50 ng/ml of GDNF.In the control group,PLZF protein was 0.34±0.13 and c-Kit protein was 0.72±0.27.In 10 ng/ml of GDNF group,PLZF protein was 0.38±0.18 and c-Kit protein was 0.69±0.26.Compared with the control group,10 ng/ml of GDNF had no influence on PLZF and c-Kit protein.In 50 ng/ml of GDNF group,PLZF protein was 0.68±0.26 and c-Kit protein was 0.35±0.15.50 ng/ml of GDNF enhanced the expression of PLZF protein(P＜0.05),decreased the expression of c-Kit protein(P＜0.05).In 100 ng/ml of GDNF group PLZF protein was 0.70±0.27 and c-Kit protein Was 0.32±0.11,100 ng/ml of GDNF had no influence on PLZF and c-Kit protein compared with 50 ng/ml of GDNF.Conclusions Higher concentration of GDNF could enhance the transcription and expression of PLZF,and decrease the transcription and expression of c-Kit in SSC.GDNF has possible role to regulate and control proliferation and differentiation of SSC. Key words: Spermatogonia; Glial cell line-derived neurotrophic factor; Promyelocytic leukaemia zinc finger; Proto-oncogene proteins; c-kit

Role of PI3-K/Akt pathway and its effect on glial cell line-derived neurotrophic factor in midbrain dopamine cells

To explore the intracellular mechanisms underlying the survival/differentiation effect of the glial cell line-derived neurotrophic factor (GDNF) on dopamine (DA) cells. Midbrain slice culture and primary cell culture were established, and the cultures were divided into 3 groups: control group, GDNF group, and the phosphatidylinositol 3-kinase/Akt (PI3-K/Akt) pathway-inhibited group. Then the expression of tyrosine hydroxylase (TH) was detected by immunostaining as well as Western blotting. GDNF treatment induced an increase in the number of TH-immunoreactive (ir) cells and the neurite number of TH-ir cells, as well as in the level of TH expression in cultures (Number of TH-ir cells in the slice culture: control group, 8.76+/-0.75; GDNF group, 18.63+/-0.95. Number of TH-ir cells and neurite number of TH-ir cells in cell culture: control group, 3.65+/-0.88 and 2.49+/-0.42; GDNF group, 6.01+/-0.43 and 4.89+/-0.46). Meanwhile, the stimulation of cultured cells with GDNF increased the phosphorylation of Akt, which is a downstream effector of PI3-K/Akt. The effects of GDNF were specifically blocked by the inhibitor of the PI3-K/Akt pathway, wortmannin (Number of TH-ir cells in slice culture: PI3-K/Akt pathway-inhibited group, 6.98+/-0.58. Number of TH-ir cells and neurite number of TH-ir cells in cell culture: PI3-K/Akt pathway-inhibited group, 3.79+/-0.62 and 2.50+/-0.25, respectively). The PI3-K/Akt pathway mediates the survival/differentiation effect of GDNF on DA cells.

Aberrant Sprouting and Downregulation of Tyrosine Hydroxylase in Lesioned Nigrostriatal Dopamine Neurons Induced by Long-Lasting Overexpression of Glial Cell Line Derived Neurotrophic Factor in the Striatum by Lentiviral Gene Transfer

The effects of sustained (up to 9 months) striatal overexpression of glial cell line derived neurotrophic factor (GDNF) on lesioned nigrostriatal dopamine (DA) neurons was studied using a recombinant lentiviral (rLV) vector to deliver GDNF into the striatum 4 weeks prior to the creation of an intrastriatal 6-hydroxydopamine lesion. The results of the amphetamine-induced rotation suggested an initial partial protection followed by a complete recovery, whereas the spontaneous motor behaviors remained impaired. There was a clear protection of the nigral tyrosine hydroxylase (TH)-positive neurons in the rLV-GDNF group compared to rats injected with the control vector encoding green fluorescent protein (GFP) (70 and 20% of the intact side, respectively). However, the striatal TH+ fiber density was equally reduced (to 20% of the intact side) in both groups. Further morphological analyses indicated that the nigrostriatal projections of the DA neurons were indeed preserved in the GDNF group. The axonal projections were visualized using two independent methods: First, retrograde labeling of the nigral cell bodies by intrastriatal Fluoro-Gold injections showed that the majority of rescued cells in the GDNF group had preserved axonal projections to striatum. Second, injections of a recombinant adeno-associated viral vector expressing GFP into the nigra was used to anterogradely fill the DA neurons and their projections with GFP protein. GFP immunostaining clearly demonstrated that the fibers of the nigral DA cells were preserved along the nigrostriatal pathway and innervated large parts of the striatum, but did not express TH at detectable levels. In addition, fiber sprouting was observed in the globus pallidus, entopeduncular nucleus, and substantia nigra, corresponding to areas where GDNF protein was released. The lack of functional recovery in the spontaneous motor behaviors may, at least in part, be explained by this extensive aberrant fiber sprouting in the downstream striatal target nuclei and/or decreased synthesis of dopamine in the striatum.

Cationic liposome-mediated GDNF gene transfer after spinal cord injury.

Glial cell line-derived neurotrophic factor (GDNF) has been shown to protect cranial and spinal motoneurons, which suggests potential uses of GDNF in the treatment of spinal cord injury (SCI) and motor neuron disease. We examined neuroprotective effect of cationic liposome-mediated GDNF gene transfer in vivo on axonal regeneration and locomotor function recovery after SCI in adult rats. The mixture of DC-Chol liposomes and recombinant plasmid pEGFP-GDNF cDNA was injected after SCI. RT-PCR confirmed the increased expression of GDNF mRNA in the injected areas at 7 days after injection. The expression of EGFP-GDNF was observed in the cells around the injection locus by fluorescence microscope at least 4 weeks after injection. Four weeks after GDNF gene transfer, regeneration of the corticospinal tracts was assessed using anterograde tract tracing. There are more HRP labeling of corticospinal tract axons across the lesion in GDNF group compared with control group. In GDNF group, the maximum distance these labeled axons extended varied in different animals and ranged from 5 mm to approximately 9 mm from the lesion. In control group, no HRP labeled axons extended caudal to the lesion. The locomotion function of hindlimbs of rats was evaluated using inclined plane test and BBB locomotor scores. The locomotion functional scores in GDNF group were higher than that in control group within 1-4 weeks after SCI (p < 0.05). These data demonstrate that in vivo transfer of GDNF cDNA can promote axonal regeneration and enhance locomotion functional recovery, suggesting that cationic liposome-mediated delivery of GDNF cDNA may be a practical gene transfer method for traumatic SCI treatment.

Glial cell line-derived neurotrophic factor protects midbrain dopamine neurons from the lethal action of the weaver gene: a quantitative immunocytochemical study

Glial cell line-derived neurotrophic factor (GDNF) has been shown to protect and repair midbrain dopamine neurons in vivo using animal models created with neurotoxins. The weaver mouse ( wv/wv) has natural and spontaneous midbrain dopaminergic cell death which gives a unique opportunity to examine the effects of GDNF. The present study was designed to investigate a possible neuroprotective role by GDNF for midbrain dopamine neurons in the wv/wv. Weaver pups were given 1 μl injections on postnatal day 1. The wv/wv placebo group received a single unilateral injection into the right lateral ventricle of phosphate buffered saline (PBS) while the GDNF treated wv/wv mice received either 1.0 μg/μl or 10.0 μg/μl GDNF in PBS. All mice were sacrificed on postnatal day 20 and their brains were processed for tyrosine hydoxylase (TH) immunocytochemistry. When compared to the placebo group, the 1 μg GDNF group showed significantly less cell death on the injection side, but the contralateral side showed no significant sparing of TH neurons. The combined counts from both sides show significantly more TH staining neurons in the 1 μg GDNF group compared to placebo. When compared to placebo-injected controls, the 10 μg GDNF treated group showed significantly more TH staining neurons on the injected side, contralateral side, and combined. The results demonstrate that GDNF does protect weaver dopaminergic midbrain neurons from the lethal action of the weaver gene and the effect is positively correlated to dosage.