Glial Cell Line-derived Neurotrophic Factor Gene Research Articles

Exploring the Gene Expression and Plasma Protein Levels of HSP90, HSP60, and GDNF in Multiple Sclerosis Patients and Healthy Controls.

Multiple sclerosis (MS) is a chronic neurodegenerative disease characterized by immune-mediated inflammation and neurodegeneration in the central nervous system (CNS). In this study; we aimed to investigate the gene expression and plasma protein levels of three neuroprotective genes-heat shock proteins (HSP90 and HSP60) and glial cell line-derived neurotrophic factor (GDNF)-in MS patients compared to healthy controls. Forty patients with relapsing-remitting MS and 40 healthy volunteers participated in this study. Gene expression was measured using reverse transcription quantitative real-time PCR, and protein levels were assessed via ELISA. The results showed a significant increase in HSP90 (1.7-fold) and HSP60 (2-fold) gene expression in MS patients compared to controls, along with corresponding increases in protein levels (1.5-fold for both HSP90 and HSP60). In contrast, GDNF gene expression and protein levels were significantly reduced in MS patients, with a 7-fold decrease in gene expression and a 1.6-fold reduction in protein levels. Notably, a non-linear relationship between GDNF gene expression and protein concentration was observed in MS patients, suggesting complex regulatory mechanisms influencing GDNF in the disease. The upregulation of HSP90 and HSP60 in MS highlights their roles in immune regulation and stress responses, while the reduction in GDNF indicates impaired neuroprotection. These findings suggest that HSP90, HSP60, and GDNF could serve as biomarkers for disease progression and as potential therapeutic targets in MS, offering promising avenues for future research and treatment development.

MicroRNA-Mediated Suppression of Glial Cell Line-Derived Neurotrophic Factor Expression Is Modulated by a Schizophrenia-Associated Non-Coding Polymorphism.

Plasma levels of glial cell line-derived neurotrophic factor (GDNF), a pivotal regulator of differentiation and survival of dopaminergic neurons, are reportedly decreased in schizophrenia. To explore the involvement of GDNF in the pathogenesis of the disease, a case-control association analysis was performed between five non-coding single nucleotide polymorphisms (SNP) across the GDNF gene and schizophrenia. Of them, the 'G' allele of the rs11111 SNP located in the 3' untranslated region (3'-UTR) of the gene was found to associate with schizophrenia. In silico analysis revealed that the rs11111 'G' allele might create binding sites for three microRNA (miRNA) species. To explore the significance of this polymorphism, transient co-transfection assays were performed in human embryonic kidney 293T (HEK293T) cells with a luciferase reporter construct harboring either the 'A' or 'G' allele of the 3'-UTR of GDNF in combination with the hsa-miR-1185-1-3p pre-miRNA. It was demonstrated that in the presence of the rs11111 'G' (but not the 'A') allele, hsa-miR-1185-2-3p repressed luciferase activity in a dose-dependent manner. Deletion of the miRNA binding site or its substitution with the complementary sequence abrogated the modulatory effect. Our results imply that the rs11111 'G' allele occurring more frequently in patients with schizophrenia might downregulate GDNF expression in a miRNA-dependent fashion.

Long-term benefits of hematopoietic stem cell-based macrophage/microglia delivery of GDNF to the CNS in a mouse model of Parkinson's disease.

Glial cell line-derived neurotrophic factor (GDNF) protects dopaminergic neurons in various models of Parkinson's disease (PD). Cell-based GDNF gene delivery mitigates neurodegeneration and improves both motor and non-motor functions in PD mice. As PD is a chronic condition, this study aims to investigate the long-lasting benefits of hematopoietic stem cell (HSC)-based macrophage/microglia-mediated CNS GDNF (MMC-GDNF) delivery in an MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) mouse model. The results indicate that GDNF treatment effectively ameliorated MPTP-induced motor deficits for up to 12 months, which coincided with the protection of nigral dopaminergic neurons and their striatal terminals. Also, the HSC-derived macrophages/microglia were recruited selectively to the neurodegenerative areas of the substantia nigra. The therapeutic benefits appear to involve two mechanisms: (1) macrophage/microglia release of GDNF-containing exosomes, which are transferred to target neurons, and (2) direct release of GDNF by macrophage/microglia, which diffuses to target neurons. Furthermore, the study found that plasma GDNF levels were significantly increased from baseline and remained stable over time, potentially serving as a convenient biomarker for future clinical trials. Notably, no weight loss, altered food intake, cerebellar pathology, or other adverse effects were observed. Overall, this study provides compelling evidence for the long-term therapeutic efficacy and safety of HSC-based MMC-GDNF delivery in the treatment of PD.

Glial cell line-derived Neurotrophic factor GDNF Gene Expression Analysis: Unveiling Neuronal Protection Mechanisms in Alzheimer's Disease Management

Background: Alzheimer's disease (AD), accounting for a substantial proportion of dementia cases, presents a formidable challenge to healthcare systems worldwide. The pathogenesis of AD in patients with Type II Diabetes Mellitus (DM) is particularly complex due to the interplay of metabolic and neurodegenerative processes. Understanding the role of Glial Cell Line-Derived Neurotrophic Factor (GDNF) in this context is vital for elucidating potential therapeutic targets. Objective: This study aimed to assess the expression levels of the GDNF gene in patients with Type II DM and dementia and to explore the correlation between GDNF expression and cognitive function. Methods: Blood samples were collected from 88 diabetic patients with dementia and 12 healthy controls. GDNF serum levels were measured using Chemiluminescent Immunoassay (CLIA), and genomic DNA was isolated for expression analysis via RT-qPCR. Cognitive function was evaluated using the Mini Mental State Examination (MMSE). Statistical analysis, including t-tests and one-way ANOVA, was performed using Graphpad Prism version 9.0. Results: Diabetic dementia patients exhibited significantly lower GDNF serum levels (4.37±1.38 µg/mL) compared to healthy controls (11.37±3.64 µg/mL, p=0.014). MMSE scores were also lower in the patient group (12.26±4.56) than in controls (24.1±3.12, p=0.009). RT-qPCR results showed a relative fold decrease in GDNF expression of 4.1 in dementia patients, indicating underexpression of the GDNF gene.1 Conclusion: The reduced expression of GDNF in patients with Type II DM and dementia underscores its potential as a biomarker for cognitive impairment. These findings pave the way for further research into GDNF-targeted therapies, which could prove pivotal in early detection and management of dementia in diabetic populations.

Vitamin D3 improves iminodipropionitrile-induced tic-like behavior in rats through regulation of GDNF/c-Ret signaling activity.

Children with chronic tic disorders (CTD), including Tourette syndrome (TS), have significantly reduced serum 25-hydroxyvitamin D [25(OH)D]. While vitamin D3 supplementation (VDS) may reduce tic symptoms in these children, its mechanism is unclear. The study aim was to investigate the effects and mechanisms of vitamin D deficiency (VDD) and VDS on TS model behavior. Forty 5-week-old male Sprague-Dawley rats were randomly divided into (n = 10 each): control, TS model, TS model with VDD (TS + VDD), or TS model with VDS (TS + VDS; two intramuscular injections of 20,000IU/200g) groups. The VDD model was diet-induced (0IU vitamin D/kg); the TS model was iminodipropionitrile (IDPN)-induced. All groups were tested for behavior, serum and striatal 25(OH)D and dopamine (DA), mRNA expressions of vitamin D receptor (VDR), glial cell line-derived neurotrophic factor (GDNF), protooncogene tyrosine-protein kinase receptor Ret (c-Ret), and DA D1 (DRD1) and D2 (DRD2) receptor genes in the striatum. TS + VDD had higher behavior activity scores throughout, and higher total behavior score at day 21 compared with TS model. In contrast, day 21 TS + VDS stereotyped behavior scores and total scores were lower than TS model. The serum 25(OH)D in TS + VDD was < 20ng/mL, and lower than control. Striatal DA of TS was lower than control. Compared with TS model, striatal DA of TS + VDD was lower, while in TS + VDS it was higher than TS model. Furthermore, mRNA expression of VDR, GDNF, and c-Ret genes decreased in TS model, and GDNF expression decreased more in TS + VDD, while TS + VDS had higher GDNF and c-Ret expressions. VDD aggravates, and VDS ameliorates tic-like behavior in an IDPN-induced model. VDS may upregulate GDNF/c-Retsignaling activity through VDR, reversing the striatal DA decrease and alleviating tic-like behavior.

Sperm-carried IGF2 downregulated the expression of mitogens produced by Sertoli cells: A paracrine mechanism for regulating spermatogenesis?

Insulin-like growth factor 2 (IGF2) mRNA has been found in human and mouse spermatozoa. It is currently unknown whether the IGF2 protein is expressed in human spermatozoa and, if so, its possible role in the cross-talk between germ and Sertoli cells (SCs) during spermatogenesis. To accomplish this, we analyzed sperm samples from four consecutive Caucasian men. Furthermore, to understand its role during the spermatogenetic process, porcine SCs were incubated with increasing concentrations (0.33, 3.33, and 10 ng/mL) of recombinant human IGF2 (rhIGF2) for 48 hours. Subsequently, the experiments were repeated by pre-incubating SCs with the non-competitive insulin-like growth factor 1 receptor (IGF1R) inhibitor NVP-AEW541. The following outcomes were evaluated: 1) Gene expression of the glial cell-line derived neurotrophic factor (GDNF), fibroblast growth factor 2 (FGF2), and stem cell factor (SCF) mitogens; 2) gene and protein expression of follicle-stimulating hormone receptor (FSHR), anti-Müllerian hormone (AMH), and inhibin B; 3) SC proliferation. We found that the IGF2 protein was present in each of the sperm samples. IGF2 appeared as a cytoplasmic protein localized in the equatorial and post-acrosomal segment and with a varying degree of expression in each cell. In SCs, IGF2 significantly downregulated GDNF gene expression in a concentration-dependent manner. FGF2 and SCF were downregulated only by the highest concentration of IGF2. Similarly, IGF2 downregulated the FSHR gene and FSHR, AMH, and inhibin B protein expression. Finally, IGF2 significantly suppressed the SC proliferation rate. All these findings were reversed by pre-incubation with NVP-AEW541, suggesting an effect mediated by the interaction of IGF2 with the IGFR. In conclusion, sperm IGF2 seems to downregulate the expression of mitogens, which are known to be physiologically released by the SCs to promote gonocyte proliferation and spermatogonial fate adoption. These findings suggest the presence of paracrine regulatory mechanisms acting on the seminiferous epithelium during spermatogenesis, by which germ cells can influence the amount of mitogens released by the SCs, their sensitivity to FSH, and their rate of proliferation.

GDNF Increases Inhibitory Synaptic Drive on Principal Neurons in the Hippocampus via Activation of the Ret Pathway.

Glial cell line-derived neurotrophic factor (GDNF) has been shown to counteract seizures when overexpressed or delivered into the brain in various animal models of epileptogenesis or chronic epilepsy. The mechanisms underlying this effect have not been investigated. We here demonstrate for the first time that GDNF enhances GABAergic inhibitory drive onto mouse pyramidal neurons by modulating postsynaptic GABAA receptors, particularly in perisomatic inhibitory synapses, by GFRα1 mediated activation of the Ret receptor pathway. Other GDNF receptors, such as NCAM or Syndecan3, are not contributing to this effect. We observed similar alterations by GDNF in human hippocampal slices resected from epilepsy patients. These data indicate that GDNF may exert its seizure-suppressant action by enhancing GABAergic inhibitory transmission in the hippocampal network, thus counteracting the increased excitability of the epileptic brain. This new knowledge can contribute to the development of novel, more precise treatment strategies based on a GDNF gene therapy approach.

GDNF rs2910702, rs3096140, and rs3812047 polymorphisms in obsessive compulsive disorder: Preliminary study

The neurobiology of obsessive-compulsive disorder (OCD) is evidenced by a strong demonstration of malfunctions in the serotonergic and dopaminergic system. Recently, glial cell line-derived neurotrophic factor (GDNF) gene polymorphisms have been emphasized in psychiatric diseases and treatment strategies that have been tried to be developed in this regard. In the literature, there are several studies investigating the relationship between GDNF gene polymorphisms and psychiatric diseases excluding OCD. Therefore, this study aimed to compare the symptomatology and GDNF gene polymorphisms in early and late-onset OCD patients. For this purpose, patients diagnosed with OCD according to DSM-V diagnostic criteria in structured clinical interviews were grouped as early and late-onset based on the age of initiation. DNA was isolated from blood samples collected from 140 subjects (70 OCD and 70 healthy controls) in EDTA tubes, and rs2910702, rs3096140, and rs3812047 polymorphisms in GDNF gene were examined by Real-Time PCR. No significant correlation was detected between GDNF and the rs2910702, rs3096140, and rs3812047 polymorphisms in early and late-onset OCD subjects (P&gt;0.05). Failure to detect correlations between OCD and GDNF gene polymorphisms might be due to the variable expression pattern of the GDNF gene in different tissues and pathologies. Therefore, future studies might be improved by including a larger group of patients and examining a wider range of tissues for the expression pattern of GDNF.

GDNF to the rescue: GDNF delivery effects on motor neurons and nerves, and muscle re-innervation after peripheral nerve injuries.

Peripheral nerve injuries commonly occur due to trauma, like a traffic accident. Peripheral nerves get severed, causing motor neuron death and potential muscle atrophy. The current golden standard to treat peripheral nerve lesions, especially lesions with large (≥ 3 cm) nerve gaps, is the use of a nerve autograft or reimplantation in cases where nerve root avulsions occur. If not tended early, degeneration of motor neurons and loss of axon regeneration can occur, leading to loss of function. Although surgical procedures exist, patients often do not fully recover, and quality of life deteriorates. Peripheral nerves have limited regeneration, and it is usually mediated by Schwann cells and neurotrophic factors, like glial cell line-derived neurotrophic factor, as seen in Wallerian degeneration. Glial cell line-derived neurotrophic factor is a neurotrophic factor known to promote motor neuron survival and neurite outgrowth. Glial cell line-derived neurotrophic factor is upregulated in different forms of nerve injuries like axotomy, sciatic nerve crush, and compression, thus creating great interest to explore this protein as a potential treatment for peripheral nerve injuries. Exogenous glial cell line-derived neurotrophic factor has shown positive effects in regeneration and functional recovery when applied in experimental models of peripheral nerve injuries. In this review, we discuss the mechanism of repair provided by Schwann cells and upregulation of glial cell line-derived neurotrophic factor, the latest findings on the effects of glial cell line-derived neurotrophic factor in different types of peripheral nerve injuries, delivery systems, and complementary treatments (electrical muscle stimulation and exercise). Understanding and overcoming the challenges of proper timing and glial cell line-derived neurotrophic factor delivery is paramount to creating novel treatments to tend to peripheral nerve injuries to improve patients’ quality of life.

Enhanced renoprotective effect of GDNF-modified adipose-derived mesenchymal stem cells on renal interstitial fibrosis

BackgroundThe therapeutic effect of mesenchymal stem cells (MSCs) from human adipose tissue on renal interstitial fibrosis has been demonstrated by several groups. However, the way to enhance the renoprotective effect of adipose-derived mesenchymal stem cells (AMSCs) and the possible mechanisms are still unclear. The present study aimed to determine whether glial cell line-derived neurotrophic factor (GDNF)-modified AMSCs hold an enhanced protective effect on renal fibrosis.MethodsAMSCs were isolated and purified for culture. The gene GDNF has been constructed to transfect into AMSCs. The ability of GFP-AMSCs and GDNF-AMSCs supernatants to promote tube formation of endothelial cells, repair damaged endothelial cell junctions, and improve endothelial cell function was compared by using tube formation assay, immunofluorescence techniques, and vascular ring assay, respectively. Furthermore, HE and Masson staining were used to observe the histological morphology of the kidney in vivo. Peritubular capillary changes were detected and analyzed by fluorescence microangiography (FMA). Meanwhile, the hypoxia, oxidative stress, fibrotic markers, and PI3K/Akt pathway proteins were measured by western blot or qRT-PCR technics.ResultsCompared with GFP-AMSCs only, GDNF-AMSCs could enhance the repair of injured endothelial cells and promote angiogenesis through secreting more growth factors in the supernatant of GDNF-AMSC culture media demonstrated in vitro studies. Studies in vivo, unilateral ureteral obstruction (UUO)-induced mice were injected with transfected AMSCs through their tail veins. We showed that enhanced homing of AMSCs was observed in the GDNF-AMSC group compared with the GFP-AMSC group. The animals treated with GDNF-AMSCs exhibited an improvement of capillary rarefaction and fibrosis induced by obstructed kidney compared with the GFP-AMSC group. Furthermore, we reported that GDNF-AMSCs protect renal tissues against microvascular injuries via activation of the PI3K/Akt signaling pathway. Therefore, GDNF-AMSCs further ameliorated the tissue hypoxia, suppressed oxidative stress, and finally inhibited endothelial to mesenchymal transition noting by decreased coexpression of endothelial cell (CD31) and myofibroblast (a-SMA) markers.ConclusionCollectively, our data indicated that the GDNF gene enhances the ability of AMSCs in improving renal microcirculation through PI3K/Akt/eNOS signaling pathway and afterward inhibit the EndMT process and kidney fibrogenesis, which should have a vast of implications in designing future remedies for chronic kidney disease (CKD) treatment.

A regulatable adenovector system for GDNF and GFP delivery in the rat hippocampus

Spatial memory performance declines in both normal aging and Alzheimer's disease. This cognitive deficit is related to hippocampus dysfunction. Gene therapy using neurotrophic factors like Glial cell line-derived neurotrophic factor (GDNF) emerges as a promising approach to ameliorate age-related cognitive deficits. We constructed a two vector regulatable system (2VRS) which consists of a recombinant adenoviral vector (RAd) harboring a Tet-Off bidirectional promoter flanked by GDNF and Green Fluorescent Protein (GFP) genes. A second adenovector, RAd-tTA, constitutively expresses the regulatory protein tTA. When cells are cotransduced by the 2VRS, tTA activates the bidirectional promoter and both transgenes are expressed. In the presence of the antibiotic doxycycline (DOX) transgene expression is silenced. We tested the 2VRS in CHO-K1 cells where we observed a dose-dependent GFP expression that was completely inhibited by DOX (1 mg/ml). The 2VRS injected in the hippocampal CA1 region transduced both neurons and astrocytes and was efficiently inhibited by DOX added to the drinking water. In order to assess GDNF biological activity we injected 2VRS and its Control (CTRL) vector in the hypothalamus and monitored body weight for one month. The results showed that GDNF retards weight recovery 6 days more than CTRL. In conclusion, our 2VRS demonstrated optimal GFP expression and showed a bioactive effect of transgenic GDNF in the brain.

Non-toxic HSC Transplantation-Based Macrophage/Microglia-Mediated GDNF Delivery for Parkinson’s Disease

Glial cell-line-derived neurotrophic factor (GDNF) is a potent neuroprotective agent in cellular and animal models of Parkinson’s disease (PD). However, CNS delivery of GDNF in clinical trials has proven challenging due to blood-brain barrier (BBB) impermeability, poor diffusion within brain tissue, and large brain size. We report that using non-toxic mobilization-enabled preconditioning, hematopoietic stem cell (HSC) transplantation-based macrophage-mediated gene delivery may provide a solution to overcome these obstacles. Syngeneic bone marrow HSCs were transduced ex vivo with a lentiviral vector expressing macrophage promoter-driven GDNF and transplanted into 14-week-old MitoPark mice exhibiting PD-like impairments. Transplant preconditioning with granulocyte colony-stimulating factor (G-CSF) and AMD3100 was used to vacate bone marrow stem cell niches. Chimerism reached ∼80% after seven transplantation cycles. Transgene-expressing macrophages infiltrated degenerating CNS regions of MitoPark mice (not wild-type littermate controls), resulting in increased GDNF levels in the midbrain. Macrophage GDNF delivery not only markedly improved motor and non-motor dysfunction, but also dramatically mitigated the loss of dopaminergic neurons in both substantia nigra and the ventral tegmental area and preserved axonal terminals in the striatum. Striatal dopamine levels were almost completely restored. Our data support further development of mobilization-enabled HSC transplantation (HSCT)-based macrophage-mediated GDNF gene delivery as a disease-modifying therapy for PD.

Association of GDNF and CNTNAP2 gene variants with gambling.

Background and aimsSome form of gambling can be observed in nearly every society, as the gratification felt upon winning in uncertain conditions is universal. A culturally distinct form of gambling, associated with a traditional sporting event of archery known as “teer,” is innate to the province of Meghalaya, India. The objective of this study was to find genetic variants underlying this unique form of behavioral addiction. To better understand game-based gambling, we studied genetic variants related to dopaminergic pathways and other genes previously linked to various psychological disorders.MethodsThis study was carried out on a sample of 196 Indo-Aryan adults from Shillong, Meghalaya. Genotyping of glial cell line-derived neurotrophic factor (GDNF) polymorphisms was carried out using real-time PCR. We further investigated 32 single nucleotide polymorphisms located in the 3′ UTR of additional genes of interest using an OpenArray® real-time PCR platform.ResultsCase–control analysis revealed a significant association between GDNF variant rs2973033 (p = .00864, χ2 = 13.132, df = 2) and contactin-associated protein-like 2 (CNTNAP2) variant rs2530311 (p = .0448, χ2 = 13.132, df = 2) with gambling.Discussion and conclusionsAssociation of the GDNF gene with gambling could be attributed to its involvement in the development and survival of dopaminergic neurons. Our result is in good agreement with previous data indicating the role of GDNF in certain substance addictions. Several rare variants in the CNTNAP2 gene were also implicated in alcohol addiction in a previous study. This pilot study provides further support for the role of GDNF and CNTNAP2 in addiction behaviors.

Glial cell line-derived neurotrophic factor (GDNF) mediates hepatic stellate cell activation via ALK5/Smad signalling

ObjectiveAlthough glial cell line-derived neurotrophic factor (GDNF) is a member of the transforming growth factor-β superfamily, its function in liver fibrosis has rarely been studied. Here, we investigated the role...

The Effect of Atypical Antipsychotic Drugs on the Neurotrophic Factors Gene Expression in the MPTP Model of Parkinson’s Disease

Atypical antipsychotics (AAP) are used in the therapy of Parkinson’s disease (PD) for elimination of psychotic symptoms. As the brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF) and cerebral dopamine neurotrophic factor (CDNF) play a crucial role in the PD treatment, the aim of our study was the investigation of the effects of chronic treatment with commonly used AAP, clozapine and quetiapine, on the motor behavior and the BDNF, GDNF and CDNF genes expression in the mouse brain in the PD model produced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Clozapine and quetiapine (1 mg/kg, i.p.) were administered 48 hours after the last MPTP injection, and treatment continued for the following 16 days. Then animals were euthanized, substantia nigra (SN), striatum (St) and hippocampus (Hc) were extracted for RT-PCR and tyrosine hydroxylase (TH) western blot assessment. MPTP treatment led to 50% depletion in the TH protein level in the St. MPTP caused significant decrease in both BDNF and GDNF mRNA level in the Hc and St, respectively. At the same time, increase in the GDNF expression in the MPTP + clozapine group in the SN was found. MPTP caused dramatic decrease in the CDNF mRNA level in the SN with simultaneous increase in the St. Both clozapine and quetiapine decreased it to a normal level in the St. The effect of AAP clozapine and quetiapine on the GDNF and CDNF genes expression in the pharmacological model of PD has been shown for the first time.

Timed GDNF gene therapy using an immune-evasive gene switch promotes long distance axon regeneration.

Neurosurgical repair in patients with proximal nerve lesions results in unsatisfactory recovery of function. Gene therapy for neurotrophic factors is a powerful strategy to promote axon regeneration. Glial cell line-derived neurotrophic factor (GDNF) gene therapy promotes motor neuron survival and axon outgrowth; however, uncontrolled delivery of GDNF results in axon entrapment. We report that time-restricted GDNF expression (1 month) using an immune-evasive doxycycline-inducible gene switch attenuated local axon entrapment in avulsed reimplanted ventral spinal roots, was sufficient to promote long-term motor neuron survival (24 weeks) and facilitated the recovery of compound muscle action potentials by 8 weeks. These improvements were associated with an increase in long-distance regeneration of motor axons. In contrast, persistent GDNF expression impaired axon regeneration by inducing axon entrapment. These findings demonstrate that timed expression can resolve the deleterious effect of uncontrolled growth factor delivery and shows that inducible growth factor gene therapy can be employed to enhance the efficacy of axon regeneration after neurosurgical repair of a proximal nerve lesion in rats. This preclinical study is an important step in the ongoing development of a neurotrophic factor gene therapy for patients with severe proximal nerve lesions.

Alterations of DNA Methylation at GDNF Gene Promoter in the Ventral Tegmental Area of Adult Depression-Like Rats Induced by Maternal Deprivation

Objective: To study the expression and DNA methylation of the Glial cell line-derived neurotrophic factor (GDNF) gene in the development of depression-like behaviors in rats experiencing maternal deprivation stress in early life.Methods: Newborn SD rats were randomly assigned to a normal control group (NOR) or maternal deprivation group (MD). An open field test (OPT), sucrose preference test (SPT), and a forced swimming test (FST) were used to evaluate rats' behaviors. Protein, mRNA, and methylation levels were measured by ELISA/Western blot, real-time PCR, and BiSulfte Amplicon sequencing PCR, respectively.Results: MD rats had significantly shorter total distance and more fecal pellets in OPT, a lower sucrose preference rate in SPT, and a longer immobility time in FST than NOR rats. Compared with NOR rats, MD rats showed a significantly higher plasma corticosterone (CORT) level. The levels of plasma dopamine (DA) and the GDNF were significantly lower in the MD rats than in NOR rats. In the ventral tegmental area (VTA) tissues, MD rats had a significantly higher level of methylation at the GDNF gene promoter than NOR rats. The expression of the GDNF mRNA and protein were significantly lower in MD rats than in NOR rats. The total distance was significantly correlated with plasma DA and GDNF, the DNA methylation level at the GDNF promoter and the GDNF mRNA level in the VTA. Fecal pellets showed a significant correlation with plasma CORT. The sucrose preference rate was significantly correlated with plasma DA, the DNA methylation level at the GDNF promoter and the GDNF mRNA level in the VTA. Immobility time showed a significant correlation with the plasma DA, the plasma GDNF and the GDNF mRNA level in the VTA.Conclusion: up-regulation of DNA methylation at the GDNF gene promotor and the subsequent down-regulation of the GDNF gene expression in the VTA, may be involved in the development of depression-like behaviors in rats experiencing MD in early life.

The effect of atypical antipsychotic drugs on the neurotrophic factors gene expression in the MPTP model of Parkinson's disease

Atypical antipsychotics (AAP) are used in the therapy of Parkinson’s disease (PD) for elimination of psychotic symptoms. As the brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF) and cerebral dopamine neurotrophic factor (CDNF) play a crucial role in the PD treatment, the aim of our study was the investigation of the effects of chronic treatment with commonly used AAP, clozapine and quetiapine, on the motor behavior and the BDNF, GDNF and CDNF genes expression in the mouse brain in the PD model produced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Clozapine and quetiapine (1 mg/kg, i.p.) were administered 48 hours after the last MPTP injection, and treatment continued for the following 16 days. Then animals were euthanized, substantia nigra (SN), striatum (St) and hippocampus (Hc) were extracted for RT-PCR and tyrosine hydroxylase (TH) western blot assessment. MPTP treatment led to 50% depletion in the TH protein level in the St. MPTP caused significant decrease in both BDNF and GDNF mRNA level in the Hc and St, respectively. At the same time, increase in the GDNF expression in the MPTP + clozapine group in the SN was found. MPTP caused dramatic decrease in the CDNF mRNA level in the SN with simultaneous increase in the St. Both clozapine and quetiapine decreased it to a normal level in the St. The effect of AAP clozapine and quetiapine on the GDNF and CDNF genes expression in the pharmacological model of PD has been shown for the first time.

Transplantation of Amniotic Fluid-Derived Stem Cells Preconditioned with Glial Cell Line-Derived Neurotrophic Factor Gene Alleviates Renal Fibrosis

Amniotic fluid-derived stem cells (AFSCs), which exhibit both embryonic and mesenchymal stem cell characteristics, have been shown to mitigate the degree of renal interstitial fibrosis. The aim of the present study was to determine whether transplantation of glial cell line-derived neurotrophic factor (GDNF)–modified AFSCs is more useful than transplantation of unmodified AFSCs for the treatment of renal interstitial fibrosis. Mice were randomly assigned to a sham-operation group (sham), a unilateral ureteral obstruction (UUO)-saline solution group (UUO), an AFSC transplantation group (AFSC) and a GDNF-modified AFSC transplantation group (GDNF-AFSC) and sacrificed at days 3 and 7 post-surgery (six in each group). We showed that GDNF-AFSCs noticeably suppressed oxidative stress and inflammation; additionally, GDNF-AFSCs positively regulated peritubular capillaries (PTCs), vascular endothelial growth factor (VEGF), hypoxia inducible factor-1α (HIF-1α), and transforming growth factor-β1 (TGF-β1) protein levels. Transmission electron microscopy (TEM) revealed that mitochondrial injury induced by the UUO model was significantly ameliorated after the mice were treated with GDNF-AFSCs. Therefore, we determined that GDNF gene promotes the abilities of AFSCs to inhibit inflammatory and oxidative stress effects, repair renal microvessels, relieve tissue hypoxia and mitochondrial damage, and, ultimately, alleviate renal interstitial fibrosis.

The In Vitro Differentiation of GDNF Gene-Engineered Amniotic Fluid-Derived Stem Cells into Renal Tubular Epithelial-Like Cells.

Amniotic fluid is an alternative source of stem cells, and human amniotic fluid-derived stem cells (AFSCs) obtained from a small amount of amniotic fluid collected during the second trimester represent a novel source for use in regenerative medicine. These AFSCs are characterized by lower diversity, a higher proliferation rate, and a wider differentiation capability than adult mesenchymal stem cells. AFSCs are selected based on the cell surface marker c-kit receptor (CD117) using immunomagnetic sorting. Glial cell line-derived neurotrophic factor (GDNF) is expressed during early kidney development and regulates the proliferation and differentiation of stem cells in vitro. In this study, c-kit-sorted AFSCs were induced toward osteogenic or adipogenic differentiation. AFSCs engineered via the insertion of GDNF were cocultured with mouse renal tubular epithelial cells (mRTECs), which were preconditioned by hypoxia-reoxygenation in vitro. After coculture for 8 days, AFSCs differentiation into epithelial-like cells was evaluated by performing immunofluorescence, flow cytometry, and quantitative real-time polymerase chain reaction to identify cells expressing the renal epithelial markers, cytokeratin 18 (CK18), E-cadherin, aquaporin-1 (AQP1), and paired box 2 gene (Pax2). The GDNF gene enhanced AFSCs differentiation into RTECs. AFSCs possess self-renewal ability and multiple differentiation potential and thus represent a new source of stem cells.