Mouse spermatogenesis entails the maintenance and self-renewal of spermatogonial stem cells (SSCs), which require a complex web-like signaling network transduced by various cytokines. Although brain-derived neurotrophic factor (BDNF) is expressed in Sertoli cells in the testis, and its receptor tropomyosin receptor kinase B (TrkB) is expressed in the spermatogonial population containing SSCs, potential functions of BDNF for spermatogenesis have not been uncovered. Here, we generate BDNF conditional knockout mice and find that BDNF is dispensable for in vivo spermatogenesis and fertility. However, in vitro , we reveal that BDNF -deficient germline stem cells (GSCs) exhibit growth potential not only in the absence of glial cell line-derived neurotrophic factor (GDNF), a master regulator for GSC proliferation, but also in the absence of other factors, including epidermal growth factor (EGF), basic fibroblast growth factor (bFGF), and insulin. GSCs grown without these factors are prone to differentiation, yet they maintain expression of promyelocytic leukemia zinc finger ( Plzf ), an undifferentiated spermatogonial marker. Inhibition of phosphoinositide 3-kinase (PI3K), mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK), and Src pathways all interfere with the growth of BDNF-deficient GSCs. Thus, our findings suggest a role for BDNF in maintaining the undifferentiated state of spermatogonia, particularly in situations where there is a shortage of growth factors.
Animals ; Male ; Brain-Derived Neurotrophic Factor/genetics* ; Spermatogonia/cytology* ; Mice ; Spermatogenesis/genetics* ; Mice, Knockout ; Cell Differentiation ; Glial Cell Line-Derived Neurotrophic Factor/genetics* ; Promyelocytic Leukemia Zinc Finger Protein/genetics* ; Cell Survival/physiology* ; Signal Transduction/physiology* ; Cell Proliferation/physiology*

OBJECTIVE: Diabetes-induced gastrointestinal (GI) motility disorders are increasingly prevalent. Damage to the enteric nervous system (ENS), composed primarily of enteric neurons and glial cells, is an essential mechanism involved in these disorders. Although electroacupuncture (EA) has shown the potential to mitigate enteric neuronal loss, its mechanism is not fully understood. Additionally, the effects of EA on enteric glial cells have not been investigated. Enteric neural precursor cells (ENPCs) contribute to the structural and functional integrity of the ENS, yet whether EA enhances their differentiation into enteric neurons and glial cells remains unexplored. This study investigates whether EA promotes ENS repair through enhancing ENPC-derived neurogenesis and gliogenesis and elucidates the potential molecular mechanisms involved. METHODS: Transgenic mice were used to trace Nestin⁺/nerve growth factor receptor (Ngfr)⁺ ENPCs labeled with green fluorescent protein (GFP) in vivo. Mice were randomly divided into four groups: control, diabetes mellitus (DM), DM + sham EA, and DM + EA. The effects of EA on diabetic mice were evaluated by GI motility, ENS structure, and ENPC differentiation. Glial cell line-derived neurotrophic factor (GDNF)/Ret signaling was detected to clarify the underlying molecular mechanisms. RESULTS: EA alleviated diabetes-induced GI motility disorders, as indicated by reduced whole gut transit time, shortened colonic bead expulsion time, and enhanced smooth muscle contractility. Furthermore, EA attenuated diabetes-induced losses of enteric neurons and glial cells, thereby restoring ENS integrity. Notably, EA reversed the diabetes-induced decrease in ENPCs and significantly increased the absolute number and the proportion of ENPC-derived enteric neurons. However, immunofluorescence analyses revealed no colocalization between EA-induced glial fibrillary acidic protein⁺ glial cells and GFP-labeled ENPCs. Mechanistically, GDNF/Ret signaling was elevated in intestinal tissues and upregulated in ENPCs in EA-treated diabetic mice. CONCLUSION EA facilitates ENS repair by promoting Nestin⁺/Ngfr⁺ ENPC differentiation into enteric neurons via upregulation of GDNF/Ret signaling, and driving enteric gliogenesis from non-Nestin⁺/Ngfr⁺ ENPCs. These findings highlight EA's role in ameliorating diabetes-induced GI dysmotility through ENPC-derived ENS restoration. Please cite this article as: Guo JL, Liu S, Ding SJ, Yang X, Du F. Electroacupuncture at ST36 improves gastrointestinal motility disorders by promoting enteric nervous system regeneration through GDNF/Ret signaling in diabetic mice. J Integr Med. 2025; 23(5):548-559.
Animals ; Electroacupuncture ; Enteric Nervous System/physiology* ; Gastrointestinal Motility/physiology* ; Glial Cell Line-Derived Neurotrophic Factor/metabolism* ; Diabetes Mellitus, Experimental/therapy* ; Signal Transduction ; Mice ; Gastrointestinal Diseases/physiopathology* ; Proto-Oncogene Proteins c-ret/metabolism* ; Mice, Transgenic ; Male ; Nerve Regeneration ; Neural Stem Cells ; Mice, Inbred C57BL ; Acupuncture Points

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.
Rats ; Male ; Animals ; Rats, Sprague-Dawley ; Electroacupuncture ; Phosphatidylinositol 3-Kinase/metabolism* ; Facial Nerve Injuries/therapy* ; Phosphatidylinositol 3-Kinases/metabolism* ; Beclin-1 ; Glial Cell Line-Derived Neurotrophic Factor ; Signal Transduction ; TOR Serine-Threonine Kinases/metabolism* ; Autophagy ; Mammals/metabolism*

OBJECTIVE: To study the expression levels of glial cell line-derived neurotrophic factor family receptor α-1 (GFRα1) and enhancer of zeste homolog 2 (EZH2) in the intestinal tissue of children with Hirschsprung's disease (HSCR), as well as the role of EZH2 in the regulation of GFRα1 gene expression and the pathogenesis of HSCR. METHODS: The samples of colon tissue with spasm from 24 children with HSCR after radical treatment of HSCR were selected as the experimental group, and the samples of necrotized colon tissue from 18 children with neonatal necrotizing enterocolitis after surgical resection were selected as the control group. Real-time PCR and Western blot were used to measure the expression levels of GFRα1 and EZH2 in colon tissue in both groups. Human neuroblastoma SH-SY5Y cells were divided into an EZH2 over-expression group and a negative control group. The cells in the EZH2 over-expression group were transfected with pCMV6-EZH2 plasmid, and those in the negative control group were transfected with pCMV6 plasmid. The expression levels of EZH2 and GFRα1 were measured after transfection. RESULTS: Compared with the control group, the experimental group had significant reductions in the mRNA and protein expression levels of GFRα1 and EZH2 in colon tissue (P<0.05), and the protein expression of EZH2 was positively correlated with that of GFRα1 (r=0.606, P=0.002). Compared with the negative control group, the EZH2 over-expression group had significant increases in the expression levels of EZH2 and GFRα1 after SH-SY5Y cells were transfected with EZH2 over-expression plasmid (P<0.05). CONCLUSIONS Low expression of EZH2 in the colon tissue of children with HSCR may be one of the causes of inadequate expression of GFRα1 and onset of HSCR.
Child ; Colon ; Enhancer of Zeste Homolog 2 Protein ; genetics ; Glial Cell Line-Derived Neurotrophic Factor Receptors ; genetics ; Hirschsprung Disease ; genetics ; Humans ; Infant, Newborn ; RNA, Messenger

Spinal cord injury (SCI) causes axonal damage and demyelination, neural cell death, and comprehensive tissue loss, resulting in devastating neurological dysfunction. Neural stem/progenitor cell (NSPCs) transplantation provides therapeutic benefits for neural repair in SCI, and glial cell line-derived neurotrophic factor (GDNF) has been uncovered to have capability of stimulating axonal regeneration and remyelination after SCI. In this study, to evaluate whether GDNF would augment therapeutic effects of NSPCs for SCI, GDNF-encoding or mock adenoviral vector-transduced human NSPCs (GDNF-or Mock-hNSPCs) were transplanted into the injured thoracic spinal cords of rats at 7 days after SCI. Grafted GDNF-hNSPCs showed robust engraftment, long-term survival, an extensive distribution, and increased differentiation into neurons and oligodendroglial cells. Compared with Mock-hNSPC- and vehicle-injected groups, transplantation of GDNF-hNSPCs significantly reduced lesion volume and glial scar formation, promoted neurite outgrowth, axonal regeneration and myelination, increased Schwann cell migration that contributed to the myelin repair, and improved locomotor recovery. In addition, tract tracing demonstrated that transplantation of GDNF-hNSPCs reduced significantly axonal dieback of the dorsal corticospinal tract (dCST), and increased the levels of dCST collaterals, propriospinal neurons (PSNs), and contacts between dCST collaterals and PSNs in the cervical enlargement over that of the controls. Finally grafted GDNF-hNSPCs substantially reversed the increased expression of voltage-gated sodium channels and neuropeptide Y, and elevated expression of GABA in the injured spinal cord, which are involved in the attenuation of neuropathic pain after SCI. These findings suggest that implantation of GDNF-hNSPCs enhances therapeutic efficiency of hNSPCs-based cell therapy for SCI.
Animals ; Axons ; Cell Death ; Cell Movement ; Cell- and Tissue-Based Therapy ; Cicatrix ; Demyelinating Diseases ; gamma-Aminobutyric Acid ; Glial Cell Line-Derived Neurotrophic Factor ; Humans ; Hyperalgesia ; Myelin Sheath ; Neuralgia ; Neurites ; Neuroglia ; Neurons ; Neuropeptide Y ; Paraplegia ; Pyramidal Tracts ; Rats ; Regeneration ; Spinal Cord Injuries ; Spinal Cord ; Therapeutic Uses ; Transplants ; Voltage-Gated Sodium Channels

Glial cell line-derived neurotrophic factor (GDNF) has been reported to be involved in negatively regulating the effects of addictive disorders. The objective of this study was to investigate alterations in the levels of GDNF in patients with Internet gaming disorder (IGD) and to assess the relationship between GDNF levels and the severity of IGD indices. Nineteen male patients with IGD and 19 sexmatched control subjects were evaluated for alteration of plasma GDNF levels and for relationship between GDNF levels and clinical characteristics of Internet gaming, including the Young's Internet Addiction Test (Y-IAT). The GDNF levels were found to be significantly low in patients with IGD (103.2±62.0 pg/mL) compared with the levels of controls (245.2±101.6 pg/mL, p<0.001). GDNF levels were negatively correlated with Y-IAT scores (Spearman's rho=-0.645, p=<0.001) and this negative correlation remained even after controlling for multiple variables (r=-0.370, p=0.048). These findings support the assumed role of GDNF in the regulation of IGD.
Case-Control Studies ; Glial Cell Line-Derived Neurotrophic Factor ; Humans ; Immunoglobulin D ; Internet ; Male ; Neuroglia ; Pilot Projects ; Plasma

While hallmarks of rodent spermatogonia stem cell biomarkers' heterogeneity have recently been identified, their stage and subset distributions remain unclear. Furthermore, it is currently difficult to accurately identify subset-specific SSC marker distributions due to the poor nuclear morphological characteristics associated with fixation in 4% paraformaldehyde. In the present study, testicular cross-sections and whole-mount samples were Bouin fixed to optimize nuclear resolution and visualized by immunohistochemistry (IHC) and immunofluorescence (IF). The results identified an expression pattern of PLZF^highc-KIT^pos in A₁ spermatogonia, while A₂-A₄-differentiating spermatogonia were PLZF^lowc-KIT^pos. Additionally, this procedure was used to examine asymmetrically expressing GFRA1 and PLZF clones, asymmetric A_pr and false clones were distinguished based on the presence or absence of TEX14, a molecular maker of intercellular bridges, despite having identical nuclear morphology and intercellular distances that were <25 μm. In conclusion, this optimized Bouin fixation procedure facilitates the accurate identification of spermatogonium subsets based on their molecular profiles and is capable of distinguishing asymmetric and false clones. Therefore, the findings presented herein will facilitate further morphological and functional analysis studies and provide further insight into spermatogonium subtypes.
Animals ; Cell Differentiation ; Fluorescent Antibody Technique ; Gene Expression Regulation/genetics* ; Glial Cell Line-Derived Neurotrophic Factor Receptors/genetics* ; Immunohistochemistry ; Male ; Mice ; Mice, Inbred C57BL ; Promyelocytic Leukemia Zinc Finger Protein/genetics* ; Proto-Oncogene Proteins c-kit/genetics* ; Seminiferous Tubules/cytology* ; Spermatogenesis ; Spermatogonia/metabolism* ; Testis/cytology* ; Tissue Fixation ; Transcription Factors/genetics*

OBJECTIVE: Some clinical studies have found alterations in the levels of serum brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) after applying antidepressant treatment in patients with major depressive disorder (MDD). We evaluated the serum BDNF and GDNF levels before and after 12 weeks of antidepressant treatment in MDD outpatients. METHODS: Serum BDNF and GDNF levels were measured in 23 female MDD outpatients at baseline and after 12 weeks of treatment. The severity of depression was measured with the Hamilton Depression Rating Scale-17 (HAMD-17). Remission of MDD to the treatment was defined as a posttreatment HAMD-17 score of <7. RESULTS: Among MDD patients, 19 (82.6%) subjects were in mild to moderate depression. The whole MDD patients had significantly higher serum BDNF and GDNF levels at baseline than those after 12 weeks of antidepressant treatment. The baseline serum BDNF and GDNF levels did not significantly between the remission and nonremission groups. The significant alteration in both BDNF and GDNF levels after antidepressant treatment were observed in patients with remission. CONCLUSION: The present study suggests that the baseline serum BDNF and GDNF levels are higher than the posttreatment levels in some mild-to-moderate MDD outpatients and the significant alteration in BDNF and GDNF level after treatment were observed in patients with remission.
Brain-Derived Neurotrophic Factor* ; Depression ; Depressive Disorder, Major* ; Female* ; Glial Cell Line-Derived Neurotrophic Factor* ; Humans ; Outpatients*

PURPOSE: To evaluate the expression of glial cell line-derived neurotrophic factor (GDNF) and its receptor, GDNF family receptor alpha subunit 1 (GFRα-1) in the pelvic (middle third) vagina and, particularly, in the paravaginal ganglia of nulliparous and primiparous rabbits. METHODS: Chinchilla-breed female rabbits were used. Primiparas were killed on postpartum day 3 and nulliparas upon reaching a similar age. The vaginal tracts were processed for histological analyses or frozen for Western blot assays. We measured the ganglionic area, the Abercrombie-corrected number of paravaginal neurons, the cross-sectional area of the neuronal somata, and the number of satellite glial cells (SGCs) per neuron. The relative expression of both GDNF and GFRα-1 were assessed by Western blotting, and the immunostaining was semiquantitated. Unpaired two-tailed Student t -test or Wilcoxon test was used to identify statistically significant differences (P≤0.05) between the groups. RESULTS: Our findings demonstrated that the ganglionic area, neuronal soma size, Abercrombie-corrected number of neurons, and number of SGCs per neuron were similar in nulliparas and primiparas. The relative expression of both GDNF and GFRα-1 was similar. Immunostaining for both GDNF and GFRα-1 was observed in several vaginal layers, and no differences were detected regarding GDNF and GFRα-1 immunostaining between the 2 groups. In the paravaginal ganglia, the expression of GDNF was increased in neurons, while that of GFRα-1 was augmented in the SGCs of primiparous rabbits. CONCLUSIONS: The present findings suggest an ongoing regenerative process related to the recovery of neuronal soma size in the paravaginal ganglia, in which GDNF and GFRα-1 could be involved in cross-talk between neurons and SGCs.
Blotting, Western ; Carisoprodol ; Female ; Ganglia ; Ganglion Cysts ; Glial Cell Line-Derived Neurotrophic Factor ; Humans ; Nerve Growth Factors ; Neuroglia ; Neuronal Plasticity ; Neurons ; Postpartum Period ; Rabbits ; Reproduction ; Vagina

BACKGROUND: For peripheral nerve regeneration, recent attentions have been paid to the nerve conduits made by tissue-engineering technique. Three major elements of tissue-engineering are cells, molecules, and scaffolds. METHODS: In this study, the attachments of nerve cells, including Schwann cells, on the nerve conduit and the effects of both growth factor and adhesion molecule on these attachments were investigated. RESULTS: The attachment of rapidly-proliferating cells, C6 cells and HS683 cells, on nerve conduit was better than that of slowly-proliferating cells, PC12 cells and Schwann cells, however, the treatment of nerve growth factor improved the attachment of slowly-proliferating cells. In addition, the attachment of Schwann cells on nerve conduit coated with fibronectin was as good as that of Schwann cells treated with glial cell line-derived neurotrophic factor (GDNF). CONCLUSIONS: Growth factor changes nerve cell morphology and affects cell cycle time. And nerve growth factor or fibronectin treatment is indispensable for Schwann cell to be used for implantation in artificial nerve conduits.
Animals ; Attention ; Cell Cycle ; Fibronectins ; Glial Cell Line-Derived Neurotrophic Factor ; Nerve Growth Factor ; Neurons* ; PC12 Cells ; Peripheral Nerves* ; Regeneration* ; Schwann Cells ; Tenascin