Mesenchymal cells regulate enteric neural crest cell migration via RET-GFRA1b trans-signaling.

During early development, the enteric nervous system forms from the migration of enteric neural crest cells (ENCCs) from the foregut to the hindgut, where they undergo proliferation and differentiation facilitated by interactions with enteric mesenchymal cells (EMCs). This study investigates the impact on ENCC migration of EMC-ENCC communication mediated by GFRA1b expressed in EMCs. GFRA1-expressing cells in day 11-12 (E11-12) mouse embryos differentiated into smooth muscle cells from E12 onwards. Observations at E12-13.5 revealed high levels of GFRA1 expression on the anti-mesenteric side of the hindgut, correlating with enhanced ENCC migration. This indicates that GFRA1 in EMCs plays a role in ENCC migration during development. Examining GFRA1 isoforms, we found high levels of GFRA1b, which lacks amino acids 140-144, in EMCs. To assess the impact of GFRA1 isoforms on EMC-ENCC communication, we conducted neurosphere drop assays. This revealed that GFRA1b-expressing cells promoted GDNF-dependent extension and increased neurite density in ENCC neurospheres. Co-culture of ENCC mimetic cells expressing RET and GFRA1a with EMC mimetic cells expressing GFRA1a, GFRA1b, or vector alone showed that only GFRA1b-expressing co-cultured cells sustained RET phosphorylation in ENCC-mimetic cells for over 120 min upon GDNF stimulation. Our study provides evidence that GFRA1b-mediated cell-to-cell communication plays a critical role in ENCC motility in enteric nervous system development. These findings contribute to understanding the cellular interactions and signaling mechanisms that underlie enteric nervous system formation and highlight potential therapeutic targets for gastrointestinal motility disorders.

Interactions between neurotrophins, mood, and physical activity under the conditions of sleep deprivation.

Sleep deprivation (DS) is the forced elimination of sleep. While brain-derived neurotrophic factor (BDNF) has been extensively studied in the context of in mood changes following DS, the role of other neurotrophins remains elusive. This study explores the impact of DS on BDNF, glial cell line-derived neurotrophic factor (GDNF), neurotrophin-3 (NT3), and neurotrophin-4 (NT4) at mRNA and protein level, considering their potential links to mood disturbances. The study involved 81 participants subjected to polysomnography (PSG) and DS. Blood samples, mood assessments, and actigraphy data were collected twice, after PSG and DS. NT mRNA expression and serum protein concentrations of BDNF, GDNF, NT3, and NT4 were measured. Participants were divided into Responders and Non-Responders based on mood improvement after DS. DS reduced BDNF mRNA expression in all participants, with no change in serum BDNF protein. GDNF protein decreased in Non-Responders, while Responders exhibited reduced GDNF mRNA. NT3 protein increased in both groups, while NT3 mRNA decreased in Respondents. NT4 protein rose universally post-DS, but NT4 mRNA remained unchanged. Physical activity (PA) negatively correlated with mRNA expression of BDNF, GDNF, and NT3 post-DS. The study's short DS duration and exclusion of immature NT forms limit comprehensive insights. GDNF, together with NT3, might play an important role in mood response to DS. PA during DS seems to impair the mRNA expression of NTs in leukocytes. Future studies on the subject of sleep deprivation might consider investigating the relationship between BDNF and NT4 in the context of their apparent redundancy.

Hepatocyte-derived exosomes deliver the lncRNA CYTOR to hepatic stellate cells and promote liver fibrosis.

Liver fibrosis is characterized by the activation and transformation of hepatic stellate cells (HSCs) induced by various injury factors. The degree of liver fibrosis can be significantly improved, but persistent injury factors present a significant therapeutic challenge. Hepatocytes are the most important parenchymal cell type in the liver. In this study, we explored the molecular mechanisms by which damaged liver cells activate HSCs through extracellular vesicles. We established a coculture model of LO2 and LX2 and validated its exosomal transmission activity. Subsequently, differentially expressed long noncoding RNAs (lncRNAs) were screened through RNA sequencing and their mechanisms of action as competing endogenous RNAs (ceRNAs) further confirmed using biological methods, such as FISH and luciferase assays. Damaged liver cells induced activation of LX2 and upregulation of liver fibrosis-related markers. Exosomes extracted and identified from the supernatant fraction contained differentially expressed lncRNA cytoskeleton regulator RNA (CYTOR) that competed with microRNA-125 (miR-125) for binding to glial cell line-derived neurotrophic factor (GDNF) in HSCs, in turn, promoting LX2 activation. MiR-125 could target and regulate both CYTOR and GDNF and vice versa, as verified using the luciferase assay. In an in vivo model, damaged liver extracellular vesicles induced the formation of liver fibrosis. Notably, downregulation of CYTOR within extracellular vesicles effectively inhibited liver fibrosis. The lncRNA CYTOR in exosomes of damaged liver cells is upregulated and modulates the expression of downstream GDNF through activity as a ceRNA, providing an effective mechanism for activation of HSCs.

Poly(rC)-binding protein 1 alleviates neurotoxicity in 6-OHDA-induced SH-SY5Y cells and modulates glial cells in neuroinflammation.

BACKGROUND: Parkinson's disease (PD) is a debilitating neurodegenerative condition characterized by the loss of dopaminergic neurons and neuroinflammation. Previous research has identified the involvement of Poly (rC)-binding protein 1 (PCBP1) in certain degenerative diseases; however, its specific mechanisms in PD remain incompletely understood. METHODS: In this study, 6-OHDA-induced neurotoxicity in the cell lines SH-SY5Y, BV-2 and HA, was used to evaluate the protective effects of PCBP1. We assessed alterations in BDNF levels in SY5Y cells, changes in GDNF expression in glial cells, as well as variations in HSP70 and NF-κB activation. Additionally, glial cells were used as the in vitro model for neuroinflammation mechanisms. RESULTS: The results indicate that the overexpression of PCBP1 significantly enhances cell growth compared to the control plasmid pEGFP/N1 group. Overexpression of PCBP1 leads to a substantial reduction in early apoptosis rates in SH-SY5Y, HA, and BV-2 cells, with statistically significant differences (p < 0.05). Furthermore, the overexpression of PCBP1 in cells results in a marked increase in the expression of HSP70, GDNF, and BDNF, while reducing NF-κB expression. Additionally, in SH-SY5Y, HA, and BV-2 cells overexpressing PCBP1, there is a decrease in the inflammatory factor IL-6 compared to the control plasmid pEGFP/N1 group, while BV-2 cells exhibit a significant increase in the anti-inflammatory factor IL-10. CONCLUSION: Our findings suggest that PCBP1 plays a substantial role in promoting cell growth and modulating the balance of neuroprotective and inflammatory factors. These results offer valuable insights into the potential therapeutic utility of PCBP1 in mitigating neuroinflammation and enhancing neuronal survival in PD.

The role of Sertoli cells-secreted factors in different stages of germ cells development in mice exposed to BDE-209.

Decabromodiphenyl ether (BDE-209), a frequently used brominated flame retardant, readily enters the environment and is difficult to degrade with bioaccumulation. BDE-209 could cause male reproductive toxicity, but the regulatory functions of Sertoli cells-secreted factors remain uncertain. In present study, male mice were treated with 75 mg/kg BDE-209 and then stopped exposure for 50 days. Exogenous Glial cell line-derived neurotrophic factor (GDNF), a Sertoli cell-secreted factor, was injected into testes of mice treated with BDE-209 for 50 days to explore the role of GDNF in BDE-209-induced reproductive toxicity. The mouse spermatogonia cell line GC-1 spg was used in vitro to further verify regulatory effects of Sertoli cells-secreted factors on meiotic initiation. The results showed that BDE-209 inhibited expressions of the self-renewal pathway GFRα-1/RAS/ERK1/2 in spermatogonial stem cells (SSCs), and reduced expressions of spermatogonia proliferation-related pathway NRG3/ERBB4 and meiosis initiation factor Stra8. Furthermore, BDE-209 decreased the levels of both GDNF and retinoic acid (RA) secreted by Sertoli cells in testes. Importantly, the alterations of above indicators induced by BDE-209 did not recover after 50-day recovery period. After exogenous GDNF injection, the decreased expression of GFRα-1/RAS/ERK in SSCs was reversed. However, the level of RA and expressions of NRG3/ERBB4/Stra8 were not restored. The in vitro experimental results showed that exogenous RA reversed the reductions in NRG3/ERBB4/Stra8 and ameliorated inhibition of GC-1 spg cells proliferation induced by BDE-209. These results suggested that Sertoli cells-secreted factors play roles in regulating various stages of germ cell development. Specifically, BDE-209 affected the self-renewal of SSCs by decreasing GDNF secretion resulting in the inhibition of GFRα-1/RAS/ERK pathway; BDE-209 hindered the proliferation of spermatogonia and initiation of meiosis by inhibiting the secretion of RA and preventing RA from binding to RARα, resulting in the suppression of NRG3/ERBB4/Stra8 pathway. As a consequence, spermatogenesis was compromised, leading to persistent male reproductive toxicity.

Reviving: restoring depression-like behaviour through glial cell-derived neurotrophic factor treatment in the medial prefrontal cortex.

BACKGROUND: Depression is a prevalent nonmotor symptom in Parkinson disease and can greatly reduce the quality of life for patients; the dopamine receptors found in glutamatergic pyramidal cells in the medial prefrontal cortex (mPFC) play a role in regulating local field activity, which in turn affects behavioural and mood disorders. Given research showing that glial cell-derived neurotrophic factor (GDNF) may have an antidepressant effect, we sought to evaluate the impact of exogenous GDNF on depression-like behaviour in mouse models of Parkinson disease. METHODS: We used an established subacute model of Parkinson disease in mice involving intraperitoneal injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), followed by brain stereotaxic injection of GDNF into the mPFC region. Subsequently, we assessed depression-like behaviour using the sucrose preference test, forced swimming test and tail suspension test, while also evaluating protein expression in the mPFC. RESULTS: We included 60 mice, divided into 3 groups, including a control group (saline injection), an MPTP plus saline injection group and an MPTP plus GDNF injection group. We found that exogenous GDNF injection into the mPFC led to an increase in dopamine receptor D1 (DRD1) protein levels. We also observed that activating the protein kinase A pathway through DRD1 produced a prolonged antidepressant response. Under GDNF stimulation, the expression of dopamine receptor D2 (DRD2) remained constant, suggesting that the DRD2 signal was ineffective in alleviating depression-like symptoms. Moreover, our investigation involved Golgi staining and Western blot techniques, which found enhanced synaptic plasticity, including increased dendritic branches, dendritic spines and retrograde protection after GDNF treatment in Parkinson disease models. LIMITATIONS: A subtle motor phenotype became evident only toward the conclusion of the behavioural testing period. The study exclusively involved male mice, and no separate control group receiving only GDNF treatment was included in the experimental design. CONCLUSION: Our findings support a positive effect of exogenous GDNF on synaptic plasticity, mediated by DRD1 signalling in the mPFC, which could facilitate depression remission in Parkinson disease.

The significance of glial cell line-derived neurotrophic factor analysis in Progressive Supranuclear Palsy.

Progressive Supranuclear Palsy (PSP) is an atypical parkinsonism. Major subtypes of the disease: PSP-Richardson's Syndrome (PSP-RS) and PSP Parkinsonism Predominant (PSP-P) vary in clinical features, the pathomechanism remains unexplored. The aim of this work is to analyze the relevance of glial cell line-derived neurotrophic factor (GDNF) evaluation in the serum and cerebrospinal fluid (CSF) in PSP subtypes and to verify its significance as a possible factor in the in vivo examination. Authors assessed the concentration of GDNF in the serum and CSF of 12 patients with PSP-RS, 12 with PSP-P and 12 controls. Additionally authors evaluated patients using Unified Parkinson's Disease Rating Scale-III part (UPDRS-III), Frontal Assessment Battery (FAB) and Magnetic Resonance Imaging (MRI). The evaluation revealed significantly increased concentrations of GDNF in the CSF among PSP-RS patients and substantially increased concentrations of GDNF in the serum in PSP-P. Though the GDNF concentrations differentiated PSP subtypes, no correlations between with clinical factors were observed however certain correlations with atrophic changes in MRI were detected. GDNF is a factor which may impact the pathogenesis of PSP. Possible implementation of GDNF as a therapeutic factor could be a perspective in the search for therapy in this currently incurable disease.

Generation of glial cell-derived neurotrophic factor (gdnf) morphants in zebrafish larvae by cerebroventricular microinjection of vivo morpholino.

Dopaminergic neurons in the brain are an important source of dopamine, which is a crucial neurotransmitter for wellbeing, memory, reward, and motor control. Deficiency of dopamine due to advanced age and accumulative dopaminergic neuron defects can lead to movement disorders such as Parkinson's disease. Glial cell-derived neurotrophic factor (GDNF) is one of many factors involved in dopaminergic neuron development and/or survival. However, other endogenous GDNF functions in the brain await further investigation. Zebrafish is a well-established genetic model for neurodevelopment and neurodegeneration studies. Importantly, zebrafish shares approximately 70% functional orthologs with human genes including GDNF. To gain a better understanding on the precise functional role of gdnf in dopaminergic neurons, our laboratory devised a targeted knockdown of gdnf in the zebrafish larval brain using vivo morpholino. Here, detailed protocols on the generation of gdnf morphants using vivo morpholino are outlined. This method can be applied for targeting of genes in the brain to determine specific spatiotemporal gene function in situ.

Utilization of the Rat Tibial Nerve Transection Model to Evaluate Cellular and Molecular Mechanisms Underpinning Denervation-Mediated Muscle Injury.

Peripheral nerve injury denervates muscle, resulting in muscle paralysis and atrophy. This is reversible if timely muscle reinnervation occurs. With delayed reinnervation, the muscle's reparative ability declines, and muscle-resident fibro-adipogenic progenitor cells (FAPs) proliferate and differentiate, inducing fibro-fatty muscle degradation and thereby physical disability. The mechanisms by which the peripheral nerve regulates FAPs expansion and differentiation are incompletely understood. Using the rat tibial neve transection model, we demonstrated an increased FAPs content and a changing FAPs phenotype, with an increased capacity for adipocyte and fibroblast differentiation, in gastrocnemius muscle post-denervation. The FAPs response was inhibited by immediate tibial nerve repair with muscle reinnervation via neuromuscular junctions (NMJs) and sensory organs (e.g., muscle spindles) or the sensory protection of muscle (where a pure sensory nerve is sutured to the distal tibial nerve stump) with reinnervation by muscle spindles alone. We found that both procedures reduced denervation-mediated increases in glial-cell-line-derived neurotrophic factor (GDNF) in muscle and that GDNF promoted FAPs adipogenic and fibrogenic differentiation in vitro. These results suggest that the peripheral nerve controls FAPs recruitment and differentiation via the modulation of muscle GDNF expression through NMJs and muscle spindles. GDNF can serve as a therapeutic target in the management of denervation-induced muscle injury.

GDNF facilitates the differentiation of ADSCs to Schwann cells and enhances nerve regeneration through GDNF/MTA1/Hes1 axis.

Adipose tissue-derived stem cells (ADSCs) are a kind of stem cells with multi-directional differentiation potential, which mainly restore tissue repair function and promote cell regeneration. It can be directionally differentiated into Schwann-like cells to promote the repair of peripheral nerve injury. Glial cell line-derived neurotrophic factor (GDNF) plays an important role in the repair of nerve injury, but the underlying mechanism remains unclear, which seriously limits its further application.The study aimed to identify the molecular mechanism by which overexpression of glial cell line-derived neurotrophic factor (GDNF) facilitates the differentiation of ADSCs into Schwann cells, enhancing nerve regeneration after injury. In vitro, ADSCs overexpressing GDNF for 48 h exhibited changes in their morphology, with 80% of the cells having two or more prominences. Compared with that of ADSCs, GDNF-ADSCs exhibited increased expression of the Schwann cell marker S100, nerve damage repair-related factors.ADSC cells in normal culture and ADSC cells were overexpressing GDNF(GDNF-ADSCs) were analysed using TMT-Based Proteomic Analysis and revealed a significantly higher expression of MTA1 in GDNF-ADSCs than in control ADSCs. Hes1 expression was significantly higher in GDNF-ADSCs than in ADSCs and decreased by MTA1 silencing, along with a simultaneous decrease in the expression of S100 and nerve damage repair factors. These findings indicate that GDNF promotes the differentiation of ADSCs into Schwann cells and induces factors that accelerate peripheral nerve damage repair.

Schwann cells modulate nociception in neurofibromatosis 1.

Pain of unknown etiology is frequent in individuals with the tumor predisposition syndrome neurofibromatosis 1 (NF1), even when tumors are absent. Nerve Schwann cells (SCs) were recently shown to play roles in nociceptive processing, and we find that chemogenetic activation of SCs is sufficient to induce afferent and behavioral mechanical hypersensitivity in wild-type mice. In mouse models, animals showed afferent and behavioral hypersensitivity when SCs, but not neurons, lacked Nf1. Importantly, hypersensitivity corresponded with SC-specific upregulation of mRNA encoding glial cell line-derived neurotrophic factor (GDNF), independently of the presence of tumors. Neuropathic pain-like behaviors in the NF1 mice were inhibited by either chemogenetic silencing of SC calcium or by systemic delivery of GDNF-targeting antibodies. Together, these findings suggest that alterations in SCs directly modulate mechanical pain and suggest cell-specific treatment strategies to ameliorate pain in individuals with NF1.

Low-Intensity Pulsed Ultrasound Protects SH-SY5Y Cells Against 6-Hydroxydopamine-Induced Neurotoxicity by Upregulating Neurotrophic Factors.

OBJECTIVE: Neonatal hypoxic-ischemic brain damage (HIBD) can have long-term implications on patients' physical and mental health, yet the available treatment options are limited. Recent research has shown that low-intensity pulsed ultrasound (LIPUS) holds promise for treating neurodegenerative diseases and traumatic brain injuries. Our objective was to explore the therapeutic potential of LIPUS for HIBD. METHODS: Due to the lack of a suitable animal model for neonatal HIBD, we will initially simulate the therapeutic effects of LIPUS on neuronal cells under oxidative stress and neuroinflammation using cell experiments. Previous studies have investigated the biologic responses following intracranial injection of 6-hydroxydopamine (6-OHDA). In this experiment, we will focus on the biologic effects produced by LIPUS treatment on neuronal cells (specifically, SH-SY5Y cells) without the presence of other neuroglial cell assistance after stimulation with 6-OHDA. RESULTS: We found that (i) pulsed ultrasound exposure, specifically three-intermittent sonication at intensities ranging from 0.1 to 0.5 W/cm², did not lead to a significant decrease in viability among SH-SY5Y cells; (ii) LIPUS treatment exhibited a positive effect on cell viability, accompanied by an increase in glial cell-derived neurotrophic factor (GDNF) levels and a decrease in caspase three levels; (iii) the administration of 6-OHDA had a significant impact on cell viability, resulting in a decrease in both brain cell-derived neurotrophic factor (BDNF) and GDNF levels, while concurrently elevating caspase three and matrix metalloproteinase-9 (MMP-9) levels; and (iv) LIPUS treatment demonstrated its potential to alleviate the changes induced by 6-OHDA, particularly in the levels of BDNF, GDNF, and tyrosine hydroxylase (TH). CONCLUSION: LIPUS treatment may possess partial therapeutic capabilities for SH-SY5Y cells damaged by 6-OHDA neurotoxicity. Our findings enhance our understanding of the effects of LIPUS treatment on cell viability and its modulation of key factors involved in the pathophysiology of HIBD and show the promising potential of LIPUS as an alternative therapeutic approach for neonates with HIBD.

Regulation of spermatogonial stem cell differentiation by Sertoli cells-derived exosomes through paracrine and autocrine signaling.

In the orchestrated environment of the testicular niche, the equilibrium between self-renewal and differentiation of spermatogonial stem cells (SSCs) is meticulously maintained, ensuring a stable stem cell reserve and robust spermatogenesis. Within this milieu, extracellular vesicles, specifically exosomes, have emerged as critical conveyors of intercellular communication. Despite their recognized significance, the implications of testicular exosomes in modulating SSC fate remain incompletely characterized. Given the fundamental support and regulatory influence of Sertoli cells (SCs) on SSCs, we were compelled to explore the role of SC-derived exosomes (SC-EXOs) in the SSC-testicular niche. Our investigation hinged on the hypothesis that SC-EXOs, secreted by SCs from the testes of 5-day-old mice-a developmental juncture marking the onset of SSC differentiation-participate in the regulation of this process. We discovered that exposure to SC-EXOs resulted in an upsurge of PLZF, MVH, and STRA8 expression in SSC cultures, concomitant with a diminution of ID4 and GFRA1 levels. Intriguingly, obstructing exosomal communication in a SC-SSC coculture system with the exosome inhibitor GW4869 attenuated SSC differentiation, suggesting that SC-EXOs may modulate this process via paracrine signaling. Further scrutiny revealed the presence of miR-493-5p within SC-EXOs, which suppresses Gdnf mRNA in SCs to indirectly restrain SSC differentiation through the modulation of GDNF expression-an indication of autocrine regulation. Collectively, our findings illuminate the complex regulatory schema by which SC-EXOs affect SSC differentiation, offering novel perspectives and laying the groundwork for future preclinical and clinical investigations.

The effects of induced type I diabetes on developmental regulation of GDNF, NRTN, and NCAM proteins in the dentate gyrus of male rat offspring.

BACKGROUND: Maternal diabetes during pregnancy can affect the neurological development of offspring. Glial cell-derived neurotrophic factor (GDNF), neurturin (NRTN), and neural cell adhesion molecules (NCAM) are three important proteins for brain development. Therefore, this study aimed to investigate the impacts of the mentioned neurotrophic factors in the hippocampal dentate gyrus (DG) of rat offspring born to diabetic mothers. METHODS: Wistar female rats were randomly allocated into diabetic (STZ-D) [(45 mg/kg BW, STZ (Streptozotocin), i.p)], diabetic + NPH insulin (STZ-INS) [(4-6 unit/kg/day SC)], and control groups. The animals in all groups were mated by non-diabetic male rats. Two weeks after birth, male pups from each group were sacrificed and then protein contents of GDNF, NRTN, and NCAM were evaluated using immunohistochemistry. RESULTS: The study found that the expression of GDNF and NRTN in the hippocampus of diabetic rat offspring was significantly higher compared to the diabetic+ insulin and control groups, respectively (P < 0.01, P < 0.001). Additionally, the expression of NCAM was significantly higher in the diabetic group the diabetic+ insulin and control groups (P < 0.01, P < 0.001). CONCLUSIONS: The results of the study revealed that diabetes during pregnancy significantly impacts the distribution pattern of GDNF, NRTN, and NCAM in the hippocampus of rat neonates.

Electroacupuncture Promotes Functional Recovery after Facial Nerve Injury in Rats by Regulating Autophagy via GDNF and PI3K/mTOR Signaling Pathway.

OBJECTIVE: To explore the mechanism of electroacupuncture (EA) in promoting recovery of the facial function with the involvement of autophagy, glial cell line-derived neurotrophic factor (GDNF), and phosphatidylinositol-3-kinase (PI3K)/mammalian target of rapamycin (mTOR) signaling pathway. METHODS: Seventy-two male Sprague-Dawley rats were randomly allocated into the control, sham-operated, facial nerve injury (FNI), EA, EA+3-methyladenine (3-MA), and EA+GDNF antagonist groups using a random number table, with 12 rats in each group. An FNI rat model was established with facial nerve crushing method. EA intervention was conducted at Dicang (ST 4), Jiache (ST 6), Yifeng (SJ 17), and Hegu (LI 4) acupoints for 2 weeks. The Simone's 10-Point Scale was utilized to monitor the recovery of facial function. The histopathological evaluation of facial nerves was performed using hematoxylin-eosin (HE) staining. The levels of Beclin-1, light chain 3 (LC3), and P62 were detected by immunohistochemistry (IHC), immunofluorescence, and reverse transcription-polymerase chain reaction, respectively. Additionally, IHC was also used to detect the levels of GDNF, Rai, PI3K, and mTOR. RESULTS: The facial functional scores were significantly increased in the EA group than the FNI group (P<0.05 or P<0.01). HE staining showed nerve axons and myelin sheaths, which were destroyed immediately after the injury, were recovered with EA treatment. The expressions of Beclin-1 and LC3 were significantly elevated and the expression of P62 was markedly reduced in FNI rats (P<0.01); however, EA treatment reversed these abnormal changes (P<0.01). Meanwhile, EA stimulation significantly increased the levels of GDNF, Rai, PI3K, and mTOR (P<0.01). After exogenous administration with autophagy inhibitor 3-MA or GDNF antagonist, the repair effect of EA on facial function was attenuated (P<0.05 or P<0.01). CONCLUSIONS: EA could promote the recovery of facial function and repair the facial nerve damages in a rat model of FNI. EA may exert this neuroreparative effect through mediating the release of GDNF, activating the PI3K/mTOR signaling pathway, and further regulating the autophagy of facial nerves.

Plasma GDNF levels in spinal dysraphism and its relation with neurological impairment in children: A point of care study.

AIMS: GDNF plays a crucial role in the stimulation of recovery, neuroplasticity and synaptic reorganization after spinal cord injury providing neuroprotection and neuroregeneration. Plasma GDNF levels are upregulated in cases of spina bifida owing to the intrauterine damage of the exposed spinal cord. Our aim was to compare the plasma GDNF levels in patients of spina bifida with non-spina bifida cases and assess the correlation with neurological impairment at one year of follow up. METHODS: Single centre prospective analysis of cases of spina bifida from 2020 to 2022 at presentation and after one year of follow up post-surgery. Cases with hernia and hydrocele without any other disorders were recruited into the control group. Plasma GDNF levels were assessed with immunoassay kits and compared with neurological involvement. RESULTS: 85 cases were included in the study. GDNF levels were elevated in cases compared to controls (mean 6.62 vs 1.76) with significant p value (<0.01). Same was observed for open and closed defects (mean 7.63 vs 4.86: p < 0.01). At follow up of 52 cases post-surgery cases with neurogenic bladder with abnormal urodynamic studies, sphincter involvement and motor impairment had significantly elevated baseline levels of GDNF compared with those who did not have this neurological impairment (p < 0.01). DISCUSSION: The neurotrophic factor up-regulation can reflect an endogenous attempt at neuroprotection against the biochemical and molecular cascades triggered by the spinal cord damage. This upregulation can be represented as important biochemical markers of severe spinal cord damage and can be associated with severity of spine injury in MMC patients. Our results are in keeping with these findings, that, there were increased levels of plasma GDNF levels in cases of spinal dysraphism compared to control population. Also, the type of lesion reflecting the severity whether a closed or an open dysraphism, showed significant difference in levels between them suggesting, yet again, more damage in open defect as expected. The levels were higher with involvement of bladder, sphincter and lower limb power. CONCLUSION: There is significant elevation of plasma GDNF levels in cases of spina bifida and this elevation is proportional to the degree of spinal damage and hence the neurological impairment. GDNF levels are a good predictor for assessing the severity of the lesion and thus the outcome in these cases. Additional prospective and long-term studies with a larger cohort are needed for a better understanding of neurotrophin pattern modulation in MMC.

Additional glial cell line-derived neurotrophic factor in vitro promotes the proliferation of undifferentiated spermatogonia from sterile cattleyak.

Cattleyak is a typically male sterile species. The meiosis process is blocked and the scarcity of spermatogenic stems cells are both contributing factors to the inability of male cattleyak to produce sperm. While Glial cell line-derived neurotrophic factor (GDNF) is the first discovered growth factor known to promote the proliferation and self-renewal of spermatogenic stem cells, its relationship to the spermatogenesis arrest of cattleyak remains unclear. In this report, we studied the differential expression of GDNF in the testis of yak and cattleyak, and discussed the optimal concentration of GDNF in the culture medium of undifferentiated spermatogonia (UDSPG) of cattleyak in vitro and the effect of GDNF on the proliferation of cattleyak UDSPG. The results indicated that GDNF expression in the testicular tissue of cattleyak was inferior to that of yak. Moreover, the optimum value for the UDSPG in vitro culture was determined to be 20-30 ng/mL for cattleyak. In vitro, the proliferation activity of UDSPG was observed to increase with additional GDNF due to the up-regulation of proliferation-related genes and the down-regulation of differentiation-related genes. We hereby report that the scarcity of cattleyak UDSPG is due to insufficient expression of GDNF, and that the addition of GDNF in vitro can promote the proliferation of cattleyak UDSPG by regulating the expression of genes related to proliferation and differentiation. This work provides a new insight to solve the issue of spermatogenic arrest in cattleyak.

Functional role of glial-derived neurotrophic factor in a mixed allergen murine model of asthma.

Our previous study showed that glial-derived neurotrophic factor (GDNF) expression is upregulated in asthmatic human lungs, and GDNF regulates calcium responses through its receptor GDNF family receptor α1 (GFRα1) and RET receptor in human airway smooth muscle (ASM) cells. In this study, we tested the hypothesis that airway GDNF contributes to airway hyperreactivity (AHR) and remodeling using a mixed allergen mouse model. Adult C57BL/6J mice were intranasally exposed to mixed allergens (ovalbumin, Aspergillus, Alternaria, house dust mite) over 4 wk with concurrent exposure to recombinant GDNF, or extracellular GDNF chelator GFRα1-Fc. Airway resistance and compliance to methacholine were assessed using FlexiVent. Lung expression of GDNF, GFRα1, RET, collagen, and fibronectin was examined by RT-PCR and histology staining. Allergen exposure increased GDNF expression in bronchial airways including ASM and epithelium. Laser capture microdissection of the ASM layer showed increased mRNA for GDNF, GFRα1, and RET in allergen-treated mice. Allergen exposure increased protein expression of GDNF and RET, but not GFRα1, in ASM. Intranasal administration of GDNF enhanced baseline responses to methacholine but did not consistently potentiate allergen effects. GDNF also induced airway thickening, and collagen deposition in bronchial airways. Chelation of GDNF by GFRα1-Fc attenuated allergen-induced AHR and particularly remodeling. These data suggest that locally produced GDNF, potentially derived from epithelium and/or ASM, contributes to AHR and remodeling relevant to asthma.NEW & NOTEWORTHY Local production of growth factors within the airway with autocrine/paracrine effects can promote features of asthma. Here, we show that glial-derived neurotrophic factor (GDNF) is a procontractile and proremodeling factor that contributes to allergen-induced airway hyperreactivity and tissue remodeling in a mouse model of asthma. Blocking GDNF signaling attenuates allergen-induced airway hyperreactivity and remodeling, suggesting a novel approach to alleviating structural and functional changes in the asthmatic airway.

Intravenously engrafted human multilineage-differentiating stress-enduring (Muse) cells rescue erectile function after rat cavernous nerve injury.

OBJECTIVE: To evaluate the effect of intravenous administration of human multilineage-differentiating stress-enduring (Muse) cells on rat postoperative erectile dysfunction (ED) with cavernous nerve (CN) injury without an immunosuppressant. MATERIALS AND METHODS: Male Sprague-Dawley rats were randomised into three groups after CN crush injury. Either human-Muse cells, non-Muse mesenchymal stem cells (MSCs) (both 1.0 × 105 cells), or vehicle was infused intravenously at 3 h after CN injury without immunosuppressant. Erectile function was assessed by measuring intracavernous pressure (ICP) and arterial pressure (AP) during pelvic nerve electrostimulation 28 days after surgery. At 48 h and 28 days after intravenous infusion of Muse cells, the homing of Muse cells and non-Muse MSCs was evaluated in the major pelvic ganglion (MPG) after CN injury. In addition, expressions of C-X-C motif chemokine ligand (Cxcl12) and glial cell line-derived neurotrophic factor (Gdnf) in the MPG were examined by real-time polymerase chain reaction. Statistical analyses and comparisons among groups were performed using one-way analysis of variance followed by the Tukey test for parametric data and Kruskal-Wallis test followed by the Dunn-Bonferroni test for non-parametric data. RESULTS: The mean (SEM) ICP/AP values at 28 days were 0.51 (0.02) in the Muse cell group, 0.37 (0.03) in the non-Muse MSC group, and 0.36 (0.04) in the vehicle group, showing a significant positive response in the Muse cell group compared with the non-Muse and vehicle groups (P = 0.013 and P = 0.010, respectively). In the MPG, Muse cells were observed to be engrafted at 48 h and expressed Schwann cell markers S100 (~46%) and glial fibrillary acidic protein (~24%) at 28 days, while non-Muse MSCs were basically not engrafted at 48 h. Higher gene expression of Cxcl12 (P = 0.048) and Gdnf (P = 0.040) was found in the MPG of the Muse group than in the vehicle group 48 h after infusion. CONCLUSION: Intravenously engrafted human Muse cells recovered rat erectile function after CN injury in a rat model possibly by upregulating Cxcl12 and Gdnf.

Dopamine regulates colonic glial cell-derived neurotrophic factor secretion through cholinergic dependent and independent pathways.

BACKGROUND AND PURPOSE: Glial cell-derived neurotrophic factor (GDNF) maintains gut homeostasis. Dopamine promotes GDNF release in astrocytes. We investigated the regulation by dopamine of colonic GDNF secretion. EXPERIMENTAL APPROACH: D1 receptor knockout (D1 R-/- ) mice, adeno-associated viral 9-short hairpin RNA carrying D2 receptor (AAV9-shD2 R)-treated mice, 6-hydroxydopamine treated (6-OHDA) rats and primary enteric glial cells (EGCs) culture were used. Incubation fluid from colonic submucosal plexus and longitudinal muscle myenteric plexus were collected for GDNF and ACh measurements. KEY RESULTS: D2 receptor-immunoreactivity (IR), but not D1 receptor-IR, was observed on EGCs. Both D1 receptor-IR and D2 receptor-IR were co-localized on cholinergic neurons. Low concentrations of dopamine induced colonic GDNF secretion in a concentration-dependent manner, which was mimicked by the D1 receptor agonist SKF38393, inhibited by TTX and atropine and eliminated in D1 R-/- mice. SKF38393-induced colonic ACh release was absent in D1 R-/- mice. High concentrations of dopamine suppressed colonic GDNF secretion, which was mimicked by the D2 receptor agonist quinpirole, and absent in AAV-shD2 R-treated mice. Quinpirole decreased GDNF secretion by reducing intracellular Ca2+ levels in primary cultured EGCs. Carbachol ( ACh analogue) promoted the release of GDNF. Quinpirole inhibited colonic ACh release, which was eliminated in the AAV9-shD2 R-treated mice. 6-OHDA treated rats with low ACh and high dopamine content showed decreased GDNF content and increased mucosal permeability in the colon. CONCLUSION AND IMPLICATIONS: Low concentrations of dopamine promote colonic GDNF secretion via D1 receptors on cholinergic neurons, whereas high concentrations of dopamine inhibit GDNF secretion via D2 receptors on EGCs and/or cholinergic neurons.