ABSTRACT
Obstructive sleep apnea (OSA) has been linked to disruptions in circadian rhythm and neurotrophin (NFT) signaling. This study explored the link between neuromodulators, chronotype, and insomnia in OSA. The participants (n = 166) underwent polysomnography (PSG) before being categorized into either the control or the OSA group. The following questionnaires were completed: Insomnia Severity Index (ISI), Epworth Sleepiness Scale, Chronotype Questionnaire (morningness-eveningness (ME), and subjective amplitude (AM). Blood samples were collected post-PSG for protein level assessment using ELISA kits for brain-derived neurotrophic factor (BDNF), proBDNF, glial-cell-line-derived neurotrophic factor, NFT3, and NFT4. Gene expression was analyzed utilizing qRT-PCR. No significant differences were found in neuromodulator levels between OSA patients and controls. The controls with insomnia exhibited elevated neuromodulator gene expression (p < 0.05). In the non-insomnia individuals, BDNF and NTF3 expression was increased in the OSA group compared to controls (p = 0.007 for both); there were no significant differences between the insomnia groups. The ISI scores positively correlated with all gene expressions in both groups, except for NTF4 in OSA (R = 0.127, p = 0.172). AM and ME were predicting factors for the ISI score and clinically significant insomnia (p < 0.05 for both groups). Compromised compensatory mechanisms in OSA may exacerbate insomnia. The correlation between chronotype and NFT expression highlights the role of circadian misalignments in sleep disruptions.
Subject(s)
Brain-Derived Neurotrophic Factor , Circadian Rhythm , Polysomnography , Sleep Apnea, Obstructive , Sleep Initiation and Maintenance Disorders , Humans , Sleep Initiation and Maintenance Disorders/metabolism , Sleep Initiation and Maintenance Disorders/physiopathology , Sleep Apnea, Obstructive/physiopathology , Sleep Apnea, Obstructive/metabolism , Sleep Apnea, Obstructive/complications , Male , Female , Middle Aged , Adult , Brain-Derived Neurotrophic Factor/blood , Brain-Derived Neurotrophic Factor/genetics , Brain-Derived Neurotrophic Factor/metabolism , Neurotransmitter Agents/metabolism , Neurotransmitter Agents/blood , Surveys and Questionnaires , Neurotrophin 3/metabolism , Neurotrophin 3/genetics , Case-Control StudiesABSTRACT
OBJECTIVE: To investigate the effects of luteolin on chronic unpredictable mild stress (CUMS)-induced depressive rats and corticosterone (CORT)-induced depressive primary hippocampal neurons, and to elucidate the mechanism behind the action. METHODS: The antidepressant mechanism of luteolin was studied by using CUMS rat model and primary hippocampal neurons in fetal rats. In vivo, novelty suppressed feeding, open-field and sucrose preference tests as well as Morris water maze were evaluated. The content of brain derived neurotrophic factor (BDNF), 5-hydroxytryptamine (5-HT), norepinephrine (NE), and dopamine (DA) in serum were detected by enzyme-linked immunosorbent assay. The mechanisms of luteolin were explored based on neurotrophin and hippocampal neurogenesis, and proliferation. Survival of the septo-temporal axis in hippocampus was assayed using the 5-bromo-2-deoxyuridine (BrdU), the expression of BDNF, neurotrophin-3 (NT-3), and nerve growth factor (NGF) in hippocampus dentate gyrus region were measured by Western-blotting. In vitro, BDNF, NT-3, tropomyosin receptor kinase B (TrkB), and phosphorylated cyclic adenosine monophosphate responsive element binding protein (p-CREB) were detected through the high content analysis (HCA) to investigate neurotrophin and apoptosis. RESULTS: Induction of CUMS in rats induced depressive symptoms, while luteolin significantly enhanced sucrose consumption, decreased feeding latency, increased locomotor activity, escape latency, distance of target quadrant and regulated the content of depressive-like biomarkers. Histology analysis revealed that luteolin increased the abundance of new born neurons that had been labeled with BrdU, BrdU + neuronal nuclear antigen, and BrdU + doublecortin in septo-temporal axis of S2 (mid-septal) and T3 (mid-temporal). Moreover, expression of BDNF, NT-3, and NGF increased significantly in the septo-temporal axis of S2 and T3. HCA showed increased expression of BDNF, NT-3, TrkB and p-CREB in primary hippocampal neurons. CONCLUSION: The results provided direct evidence that luteolin has an antidepressant effect and could effectively promote the regeneration of the septotemporal axis nerve and hippocampal neuronutrition, which suggested that the antidepressant effect of luteolin may be related to hippocampal neurogenesis.
Subject(s)
Brain-Derived Neurotrophic Factor , Hippocampus , Luteolin , Neurogenesis , Neurons , Rats, Sprague-Dawley , Animals , Luteolin/pharmacology , Rats , Hippocampus/drug effects , Hippocampus/metabolism , Neurogenesis/drug effects , Male , Brain-Derived Neurotrophic Factor/metabolism , Brain-Derived Neurotrophic Factor/genetics , Neurons/drug effects , Neurons/metabolism , Humans , Stress, Psychological/physiopathology , Stress, Psychological/drug therapy , Female , Depression/drug therapy , Depression/metabolism , Depression/physiopathology , Antidepressive Agents/pharmacology , Neurotrophin 3/metabolism , Neurotrophin 3/geneticsABSTRACT
Loss of synapses between spiral ganglion neurons and inner hair cells (IHC synaptopathy) leads to an auditory neuropathy called hidden hearing loss (HHL) characterized by normal auditory thresholds but reduced amplitude of sound-evoked auditory potentials. It has been proposed that synaptopathy and HHL result in poor performance in challenging hearing tasks despite a normal audiogram. However, this has only been tested in animals after exposure to noise or ototoxic drugs, which can cause deficits beyond synaptopathy. Furthermore, the impact of supernumerary synapses on auditory processing has not been evaluated. Here, we studied mice in which IHC synapse counts were increased or decreased by altering neurotrophin 3 (Ntf3) expression in IHC supporting cells. As we previously showed, postnatal Ntf3 knockdown or overexpression reduces or increases, respectively, IHC synapse density and suprathreshold amplitude of sound-evoked auditory potentials without changing cochlear thresholds. We now show that IHC synapse density does not influence the magnitude of the acoustic startle reflex or its prepulse inhibition. In contrast, gap-prepulse inhibition, a behavioral test for auditory temporal processing, is reduced or enhanced according to Ntf3 expression levels. These results indicate that IHC synaptopathy causes temporal processing deficits predicted in HHL. Furthermore, the improvement in temporal acuity achieved by increasing Ntf3 expression and synapse density suggests a therapeutic strategy for improving hearing in noise for individuals with synaptopathy of various etiologies.
Subject(s)
Hair Cells, Auditory, Inner , Neurotrophin 3 , Synapses , Animals , Hair Cells, Auditory, Inner/metabolism , Hair Cells, Auditory, Inner/pathology , Synapses/metabolism , Synapses/physiology , Neurotrophin 3/metabolism , Neurotrophin 3/genetics , Mice , Auditory Threshold , Evoked Potentials, Auditory/physiology , Reflex, Startle/physiology , Auditory Perception/physiology , Spiral Ganglion/metabolism , Female , Male , Hearing Loss, HiddenABSTRACT
Cancer patients undergoing treatment with antineoplastic drugs often experience chemotherapy-induced neuropathic pain (CINP), and the therapeutic options for managing CINP are limited. Here, we show that systemic paclitaxel administration upregulates the expression of neurotrophin-3 (Nt3) mRNA and NT3 protein in the neurons of dorsal root ganglia (DRG), but not in the spinal cord. Blocking NT3 upregulation attenuates paclitaxel-induced mechanical, heat, and cold nociceptive hypersensitivities and spontaneous pain without altering acute pain and locomotor activity in male and female mice. Conversely, mimicking this increase produces enhanced responses to mechanical, heat, and cold stimuli and spontaneous pain in naive male and female mice. Mechanistically, NT3 triggers tropomyosin receptor kinase C (TrkC) activation and participates in the paclitaxel-induced increases of C-C chemokine ligand 2 (Ccl2) mRNA and CCL2 protein in the DRG. Given that CCL2 is an endogenous initiator of CINP and that Nt3 mRNA co-expresses with TrkC and Ccl2 mRNAs in DRG neurons, NT3 likely contributes to CINP through TrkC-mediated activation of the Ccl2 gene in DRG neurons. NT3 may be thus a potential target for CINP treatment.
Subject(s)
Chemokine CCL2 , Ganglia, Spinal , Neuralgia , Neurons , Neurotrophin 3 , Paclitaxel , Receptor, trkC , Animals , Female , Male , Mice , Antineoplastic Agents/adverse effects , Chemokine CCL2/metabolism , Chemokine CCL2/genetics , Ganglia, Spinal/metabolism , Ganglia, Spinal/drug effects , Neuralgia/chemically induced , Neuralgia/metabolism , Neuralgia/genetics , Neurons/metabolism , Neurons/drug effects , Neurotrophin 3/metabolism , Neurotrophin 3/genetics , Paclitaxel/adverse effects , Paclitaxel/pharmacology , Receptor, trkC/metabolism , Receptor, trkC/genetics , RNA, Messenger/metabolism , RNA, Messenger/genetics , Nerve Growth Factors/genetics , Nerve Growth Factors/metabolismABSTRACT
At the center of the hippocampal tri-synaptic loop are synapses formed between mossy fiber (MF) terminals from granule cells in the dentate gyrus (DG) and proximal dendrites of CA3 pyramidal neurons. However, the molecular mechanism regulating the development and function of these synapses is poorly understood. In this study, we showed that neurotrophin-3 (NT3) was expressed in nearly all mature granule cells but not CA3 cells. We selectively deleted the NT3-encoding Ntf3 gene in the DG during the first two postnatal weeks to generate a Ntf3 conditional knockout (Ntf3-cKO). Ntf3-cKO mice of both sexes had normal hippocampal cytoarchitecture but displayed impairments in contextual memory, spatial reference memory, and nest building. Furthermore, male Ntf3-cKO mice exhibited anxiety-like behaviors, whereas female Ntf3-cKO showed some mild depressive symptoms. As MF-CA3 synapses are essential for encoding of contextual memory, we examined synaptic transmission at these synapses using ex vivo electrophysiological recordings. We found that Ntf3-cKO mice had impaired basal synaptic transmission due to deficits in excitatory postsynaptic currents mediated by AMPA receptors but normal presynaptic function and intrinsic excitability of CA3 pyramidal neurons. Consistent with this selective postsynaptic deficit, Ntf3-cKO mice had fewer and smaller thorny excrescences on proximal apical dendrites of CA3 neurons and lower GluR1 levels in the stratum lucidum area where MF-CA3 synapses reside but normal MF terminals, compared with control mice. Thus, our study indicates that NT3 expressed in the dentate gyrus is crucial for the postsynaptic structure and function of MF-CA3 synapses and hippocampal-dependent memory.
Subject(s)
CA3 Region, Hippocampal , Dentate Gyrus , Mice, Knockout , Mossy Fibers, Hippocampal , Neurotrophin 3 , Synapses , Animals , Dentate Gyrus/metabolism , Mossy Fibers, Hippocampal/metabolism , Synapses/metabolism , Mice , Neurotrophin 3/metabolism , Neurotrophin 3/genetics , Male , Female , CA3 Region, Hippocampal/metabolism , Pyramidal Cells/metabolism , Pyramidal Cells/physiology , Excitatory Postsynaptic Potentials/physiology , Synaptic Transmission/physiology , Cognition/physiology , Hippocampus/metabolism , Mice, Inbred C57BL , Memory/physiology , Receptors, AMPA/metabolismABSTRACT
BACKGROUND: Maintaining the repair phenotype of denervated Schwann cells in the injured distal nerve is crucial for promoting peripheral nerve regeneration. However, when chronically denervated, the capacity of Schwann cells to support repair and regeneration deteriorates, leading to peripheral nerve regeneration and poor functional recovery. Herein, we investigated whether neurotrophin-3 (NT-3) could sustain the reparative phenotype of Schwann cells and promote peripheral nerve regeneration after chronic denervation and aimed to uncover its potential molecular mechanisms. METHODS: Western blot was employed to investigate the relationship between the expression of c-Jun and the reparative phenotype of Schwann cells. The inducible expression of c-Jun by NT-3 was examined both in vitro and in vivo with western blot and immunofluorescence staining. A chronic denervation model was established to study the role of NT-3 in peripheral nerve regeneration. The number of regenerated distal axons, myelination of regenerated axons, reinnervation of neuromuscular junctions, and muscle fiber diameters of target muscles were used to evaluate peripheral nerve regeneration by immunofluorescence staining, transmission electron microscopy (TEM), and hematoxylin and eosin (H&E) staining. Adeno-associated virus (AAV) 2/9 carrying shRNA, small molecule inhibitors, and siRNA were employed to investigate whether NT-3 could signal through the TrkC/ERK pathway to maintain c-Jun expression and promote peripheral nerve regeneration after chronic denervation. RESULTS: After peripheral nerve injury, c-Jun expression progressively increased until week 5 and then began to decrease in the distal nerve following denervation. NT-3 upregulated the expression of c-Jun in denervated Schwann cells, both in vitro and in vivo. NT-3 promoted peripheral nerve regeneration after chronic denervation, mainly by upregulating or maintaining a high level of c-Jun rather than NT-3 itself. The TrkC receptor was consistently presented on denervated Schwann cells and served as NT-3 receptors following chronic denervation. NT-3 mainly upregulated c-Jun through the TrkC/ERK pathway. CONCLUSION: NT-3 promotes peripheral nerve regeneration by maintaining the repair phenotype of Schwann cells after chronic denervation via the TrkC/ERK/c-Jun pathway. It provides a potential target for the clinical treatment of peripheral nerve injury after chronic denervation.
Subject(s)
Nerve Regeneration , Neurotrophin 3 , Peripheral Nerve Injuries , Schwann Cells , Humans , Axons/metabolism , Denervation , MAP Kinase Signaling System , Nerve Regeneration/genetics , Nerve Regeneration/physiology , Neurotrophin 3/genetics , Neurotrophin 3/metabolism , Peripheral Nerve Injuries/genetics , Peripheral Nerve Injuries/metabolism , Peripheral Nerve Injuries/therapy , Receptor Protein-Tyrosine Kinases/metabolism , Schwann Cells/metabolismABSTRACT
To explore the effects of butylphthalide on the levels of serum CRP, PAPK7, NT-3 and neurological function in patients with acute cerebral infarction (ACI). 120 patients with ACI who were treated at Peking University First Hospital from September 2014 to June 2016 were selected as the research objects. The patients were randomly divided into a control group and an observation group, with 60 cases in each group. Conventional methods were adopted in the control group, and the observation group used butylphthalide for treatment. Two months later, the clinical efficacy, serum C-reactive protein (CRP), Parkinson's disease protein 7 (PAPK7), neurotrophic factor-3 (NT-3) levels, and the National Institutes of Health Stroke Scale (NIHSS) score before and after treatment were put into comparison and analysis. Before treatment, the NIHSS score showed no significant difference between the two groups (p>0.05); An observably higher NIHSS score of the observation group compared with the control group was seen after treatment (p=0.000). Butylphthalide has a significant therapeutic effect on patients with ACI. It can effectively restore the patients' neurological function, and remarkably improve the serum CRP, PAPK7 and NT-3 levels, which is worthy of clinical promotion.
Subject(s)
Benzofurans , C-Reactive Protein , Cerebral Infarction , Gene Expression Regulation , Neurotrophin 3 , Protein Deglycase DJ-1 , Aged , Female , Humans , Male , Benzofurans/pharmacology , Benzofurans/therapeutic use , C-Reactive Protein/metabolism , Cerebral Infarction/drug therapy , Gene Expression Regulation/drug effects , Neuroprotective Agents/pharmacology , Neuroprotective Agents/therapeutic use , Neurotrophin 3/blood , Neurotrophin 3/genetics , Neurotrophin 3/metabolism , Protein Deglycase DJ-1/blood , Protein Deglycase DJ-1/genetics , Protein Deglycase DJ-1/metabolismABSTRACT
The neurobiology of schizophrenia is multifactorial, comprising the dysregulation of several biochemical pathways and molecules. This research proposes a peripheral biomarker for schizophrenia that involves the second extracellular loop of norepinephrine transporter (NEText), the tropomyosin receptor kinase C (TrkC), and the neurotrophin-3 (NT-3) in T cells. The study of NEText, NT-3, and TrkC was performed in T cells and plasma extracted from peripheral blood of 54 patients with schizophrenia and 54 healthy controls. Levels of NT-3, TrkC, and NET were significantly lower in plasma and T cells of patients compared to healthy controls. Co-immunoprecipitation (co-IPs) showed protein interactions with Co-IP NEText-NT-3 and Co-IP NEText-TrkC. Computational modelling of protein-peptide docking by CABS-dock provided a medium-high accuracy model for NT-3-NEText (4.6935 Å) and TrkC-NEText (2.1365 Å). In summary, immunocomplexes reached statistical relevance in the T cells of the control group contrary to the results obtained with schizophrenia. The reduced expression of NT-3, TrkC, and NET, and the lack of molecular complexes in T cells of patients with schizophrenia may lead to a peripheral dysregulation of intracellular signaling pathways and an abnormal reuptake of norepinephrine (NE) by NET. This peripheral molecular biomarker underlying schizophrenia reinforces the role of neurotrophins, and noradrenergic and immune systems in the pathophysiology of schizophrenia.
Subject(s)
Molecular Docking Simulation , Neurotrophin 3/chemistry , Norepinephrine Plasma Membrane Transport Proteins/chemistry , Receptor, trkC/chemistry , Schizophrenia/etiology , Adult , Biomarkers/metabolism , Female , Humans , Male , Middle Aged , Neurotrophin 3/genetics , Neurotrophin 3/metabolism , Norepinephrine Plasma Membrane Transport Proteins/genetics , Norepinephrine Plasma Membrane Transport Proteins/metabolism , Protein Structure, Secondary , Receptor, trkC/genetics , Receptor, trkC/metabolism , Schizophrenia/genetics , Schizophrenia/metabolismABSTRACT
Spinal cord injury (SCI) leads to numerous chronic and debilitating functional deficits that greatly affect quality of life. While many pharmacological interventions have been explored, the current unsurpassed therapy for most SCI sequalae is exercise. Exercise has an expansive influence on peripheral health and function, and by activating the relevant neural pathways, exercise also ameliorates numerous disorders of the central nervous system (CNS). While the exact mechanisms by which this occurs are still being delineated, major strides have been made in the past decade to understand the molecular underpinnings of this essential treatment. Exercise rapidly and prominently affects dendritic sprouting, synaptic connections, neurotransmitter production and regulation, and ionic homeostasis, with recent literature implicating an exercise-induced increase in neurotrophins as the cornerstone that binds many of these effects together. The field encompasses vast complexity, and as the data accumulate, disentangling these molecular pathways and how they interact will facilitate the optimization of intervention strategies and improve quality of life for individuals affected by SCI. This review describes the known molecular effects of exercise and how they alter the CNS to pacify the injury environment, increase neuronal survival and regeneration, restore normal neural excitability, create new functional circuits, and ultimately improve motor function following SCI.
Subject(s)
Exercise , Gene Expression Regulation , Nerve Regeneration/genetics , Neuronal Plasticity/genetics , Recovery of Function/genetics , Spinal Cord Injuries/genetics , Animals , Brain-Derived Neurotrophic Factor/genetics , Brain-Derived Neurotrophic Factor/metabolism , Glial Cell Line-Derived Neurotrophic Factor/genetics , Glial Cell Line-Derived Neurotrophic Factor/metabolism , Humans , Neurotrophin 3/genetics , Neurotrophin 3/metabolism , Quality of Life , Receptor, Serotonin, 5-HT2A/genetics , Receptor, Serotonin, 5-HT2A/metabolism , Serotonin/metabolism , Signal Transduction , Spinal Cord/metabolism , Spinal Cord/pathology , Spinal Cord Injuries/metabolism , Spinal Cord Injuries/pathology , Spinal Cord Injuries/rehabilitation , Symporters/genetics , Symporters/metabolismABSTRACT
Elevated glucocorticoid level in the early postnatal period is associated with glucocorticoid therapy prescribed at preterm delivery most often has severe long-lasting neurodevelopmental and behavioural effects. Detailed molecular mechanisms of such programming action of antenatal glucocorticoids on behaviour are still poorly understood. To address this question we studied neurotrophins: Bdnf, Nt-3, Ngf and their receptors: p75ngfr, Sorcs3 expression changes after subcutaneous dexamethasone (DEX) 0.2 mg/kg injection to P2 rat pups. Neurotrophins expression level was studied in the hippocampus (HPC). Disturbances in these brain regions have been implicated in the emergence of multiple psychopathologies. p75ngfr and Sorcs3 expression was studied in the brainstem-region where monoamine neurons are located. Immunohistochemically P75NTR protein level changes after DEX were investigated in the brainstem Locus Coereleus norepinephrine neurons (NE). In the first hours after DEX administration elevation of neurotrophins expression in HPC and decline of receptor's expression in the NE brainstem neurons were observed. Another critical time point during maturation is adolescence. Impact of elevated glucocorticoid level in the neonatal period and unpredictable stress (CMUS) at the end of adolescence on depressive-like behaviour was studied. Single neonatal DEX injection leads to decrease in depressive-like behaviour, observed in FST, independently from chronic stress. Neonatal DEX administration decreased Ntf3 and SorCS1 expression in the brainstem. Also Bdnf mRNA level in the brainstem of these animals didn't decrease after FST. CMUS at the end of adolescence changed p75ngfr and SorCS3 expression in the brainstem in the animals that received single neonatal DEX administration.
Subject(s)
Brain-Derived Neurotrophic Factor/metabolism , Depression/etiology , Dexamethasone/adverse effects , Nerve Tissue Proteins/metabolism , Neurotrophin 3/metabolism , Receptors, Cell Surface/metabolism , Receptors, Growth Factor/metabolism , Animals , Animals, Newborn , Brain Stem/metabolism , Brain-Derived Neurotrophic Factor/genetics , Dexamethasone/administration & dosage , Disease Models, Animal , Hippocampus/metabolism , Nerve Tissue Proteins/genetics , Neurotrophin 3/genetics , RNA, Messenger/metabolism , Rats , Rats, Wistar , Receptors, Cell Surface/genetics , Receptors, Growth Factor/genetics , Stress, Psychological/etiologyABSTRACT
AIMS: This study was aimed to investigate whether electroacupuncture (EA) would increase the secretion of neurotrophin-3 (NT-3) from injured spinal cord tissue, and, if so, whether the increased NT-3 would promote the survival, differentiation, and migration of grafted tyrosine kinase C (TrkC)-modified mesenchymal stem cell (MSC)-derived neural network cells. We next sought to determine if the latter would integrate with the host spinal cord neural circuit to improve the neurological function of injured spinal cord. METHODS: After NT-3-modified Schwann cells (SCs) and TrkC-modified MSCs were co-cultured in a gelatin sponge scaffold for 14 days, the MSCs differentiated into neuron-like cells that formed a MSC-derived neural network (MN) implant. On this basis, we combined the MN implantation with EA in a rat model of spinal cord injury (SCI) and performed immunohistochemical staining, neural tracing, electrophysiology, and behavioral testing after 8 weeks. RESULTS: Electroacupuncture application enhanced the production of endogenous NT-3 in damaged spinal cord tissues. The increase in local NT-3 production promoted the survival, migration, and maintenance of the grafted MN, which expressed NT-3 high-affinity TrkC. The combination of MN implantation and EA application improved cortical motor-evoked potential relay and facilitated the locomotor performance of the paralyzed hindlimb compared with those of controls. These results suggest that the MN was better integrated into the host spinal cord neural network after EA treatment compared with control treatment. CONCLUSIONS: Electroacupuncture as an adjuvant therapy for TrkC-modified MSC-derived MN, acted by increasing the local production of NT-3, which accelerated neural network reconstruction and restoration of spinal cord function following SCI.
Subject(s)
Electroacupuncture/methods , Mesenchymal Stem Cells/metabolism , Nerve Net/metabolism , Nerve Regeneration/physiology , Neurotrophin 3/biosynthesis , Receptor, trkC/administration & dosage , Spinal Cord Injuries/metabolism , Animals , Animals, Newborn , Coculture Techniques , Female , Neurotrophin 3/genetics , Rats , Rats, Sprague-Dawley , Rats, Transgenic , Schwann Cells/metabolism , Schwann Cells/transplantation , Spinal Cord Injuries/pathology , Spinal Cord Injuries/therapyABSTRACT
Tropomyosin receptor kinase B (Trk-B) belongs to the second largest family of membrane receptors, Receptor Tyrosine Kinases (RTKs). Trk-B is known to interact with three different neurotrophins: Brain-Derived Neurotrophic Factor (BDNF), Neurotrophin-4 (NT-4), and Neurotrophin-3 (NT-3). All three neurotrophins are involved in survival and proliferation of neuronal cells, but each induces distinct signaling through Trk-B. We hypothesize that the different biological effects correlate with differences in the interactions between the Trk-B receptors, when bound to different ligands, in the plasma membrane. To test this hypothesis, we use quantitative FRET to characterize Trk-B dimerization in response to NT-3 and NT-4 in live cells, and compare it to the previously published data for Trk-B in the absence and presence of BDNF. Our study reveals that the distinct Trk-B signaling outcomes are underpinned by both different configurations and different stabilities of the three ligand-bound Trk-B dimers in the plasma membrane.
Subject(s)
Brain-Derived Neurotrophic Factor/metabolism , Cell Membrane/metabolism , Membrane Glycoproteins/metabolism , Nerve Growth Factors/metabolism , Neurotrophin 3/metabolism , Protein Multimerization , Receptor, trkB/metabolism , Brain-Derived Neurotrophic Factor/genetics , Cell Membrane/genetics , Fluorescence Resonance Energy Transfer , HEK293 Cells , Humans , Ligands , Membrane Glycoproteins/genetics , Nerve Growth Factors/genetics , Neurotrophin 3/genetics , Receptor, trkB/geneticsABSTRACT
The carotid body may undergo plasticity changes during development/ageing and in response to environmental (hypoxia and hyperoxia), metabolic, and inflammatory stimuli. The different cell types of the carotid body express a wide series of growth factors and corresponding receptors, which play a role in the modulation of carotid body function and plasticity. In particular, type I cells express nerve growth factor, brain-derived neurotrophic factor, neurotrophin 3, glial cell line-derived neurotrophic factor, ciliary neurotrophic factor, insulin-like-growth factor-I and -II, basic fibroblast growth factor, epidermal growth factor, transforming growth factor-α and -ß, interleukin-1ß and -6, tumor necrosis factor-α, vascular endothelial growth factor, and endothelin-1. Many specific growth factor receptors have been identified in type I cells, indicating autocrine/paracrine effects. Type II cells may also produce growth factors and express corresponding receptors. Future research will have to consider growth factors in further experimental models of cardiovascular, metabolic, and inflammatory diseases and in human (normal and pathologic) samples. From a methodological point of view, microarray and/or proteomic approaches would permit contemporary analyses of large groups of growth factors. The eventual identification of physical interactions between receptors of different growth factors and/or neuromodulators could also add insights regarding functional interactions between different trophic mechanisms.
Subject(s)
Brain-Derived Neurotrophic Factor/genetics , Carotid Body/metabolism , Hyperoxia/genetics , Hypoxia/genetics , Nerve Growth Factor/genetics , Receptors, Growth Factor/genetics , Animals , Brain-Derived Neurotrophic Factor/metabolism , Carotid Body/cytology , Ciliary Neurotrophic Factor/genetics , Ciliary Neurotrophic Factor/metabolism , Epidermal Growth Factor/genetics , Epidermal Growth Factor/metabolism , Fibroblast Growth Factor 2/genetics , Fibroblast Growth Factor 2/metabolism , Gene Expression Regulation , Glial Cell Line-Derived Neurotrophic Factor/genetics , Glial Cell Line-Derived Neurotrophic Factor/metabolism , Humans , Hyperoxia/metabolism , Hyperoxia/pathology , Hypoxia/metabolism , Hypoxia/pathology , Insulin-Like Growth Factor I/genetics , Insulin-Like Growth Factor I/metabolism , Nerve Growth Factor/metabolism , Neurotrophin 3/genetics , Neurotrophin 3/metabolism , Receptors, Growth Factor/metabolism , Transforming Growth Factor alpha/genetics , Transforming Growth Factor alpha/metabolism , Transforming Growth Factor beta/genetics , Transforming Growth Factor beta/metabolism , Vascular Endothelial Growth Factor A/genetics , Vascular Endothelial Growth Factor A/metabolismABSTRACT
Neurotrophin-3 (NT-3) belongs to a family of growth factors called neurotrophins whose actions are centered in the nervous system. NT-3 is structurally related to other neurotrophins like brain-derived neurotrophic factor. The expression of NT-3 starts with the onset of neurogenesis and continues throughout life. A wealth of information links NT-3 to the growth, differentiation, and survival of hippocampal cells as well as sympathetic and sensory neurons. These studies have described the distribution of NT-3 and its receptors throughout development and in the mature nervous system. Prior works has begun to cell-type specific impact of NT-3 as well as identify the signaling pathways involved. However, much less is known about how NT-3 regulates synaptic transmission. This chapter focuses role of NT-3 in the modulation of synaptic transmission.
Subject(s)
Gene Expression Regulation/physiology , Neurotrophin 3/metabolism , Synaptic Transmission/physiology , Animals , Humans , Neurotrophin 3/genetics , Receptor, trkC/genetics , Receptor, trkC/metabolismABSTRACT
BACKGROUND: Depression is a highly prevalent mental illness that severely impacts the quality of life of affected individuals. Our recent studies demonstrated that diterpene ginkgolides (DG) have antidepressant effects in mice. However, the underlying molecular mechanisms remained much unclear. METHODS: In this study, we assessed the antidepressant effects of chronic DG therapy in rats by evaluating depression-related behaviors, we also examined potential side effects using biochemical indicators. Furthermore, we performed an in-depth molecular network analysis of gene-protein-metabolite interactions on the basis of metabolomics. RESULTS: Chronic DG treatment significantly ameliorated the depressive-like behavioral phenotype. Furthermore, the neurotrophin signaling-related NT3-TrkA and Ras-MAPK pathways may play an important role in the antidepressant effect of DG in the hippocampus. CONCLUSION: These findings provide novel insight into the mechanisms underlying the antidepressant action of DG, and should help advance the development of new therapeutic strategies for depression.
Subject(s)
Antidepressive Agents/pharmacology , Behavior, Animal/drug effects , Depression/drug therapy , Diterpenes/pharmacology , Ginkgolides/pharmacology , Signal Transduction/drug effects , Animals , Antidepressive Agents/administration & dosage , Diterpenes/administration & dosage , Ginkgolides/administration & dosage , Hippocampus/drug effects , Injections, Intraperitoneal , Male , Mitogen-Activated Protein Kinases/genetics , Mitogen-Activated Protein Kinases/metabolism , Neurotrophin 3/genetics , Neurotrophin 3/metabolism , Proto-Oncogene Proteins p21(ras)/genetics , Proto-Oncogene Proteins p21(ras)/metabolism , Rats , Rats, Sprague-Dawley , Receptor Protein-Tyrosine Kinases/genetics , Receptor Protein-Tyrosine Kinases/metabolismABSTRACT
Hearing impairment is a major health and economic concern worldwide. Currently, the cochlear implant (CI) is the standard of care for remediation of severe to profound hearing loss, and in general, contemporary CIs are highly successful. But there is great variability in outcomes among individuals, especially in children, with many CI users deriving much less or even marginal benefit. Much of this variability is related to differences in auditory nerve survival, and there has been substantial interest in recent years in exploring potential therapies to improve survival of the cochlear spiral ganglion neurons (SGN) after deafness. Preclinical studies using osmotic pumps and other approaches in deafened animal models to deliver neurotrophic factors (NTs) directly to the cochlea have shown promising results, especially with Brain-Derived Neurotrophic Factor (BDNF). More recent studies have focused on the use of NT gene therapy to force expression of NTs by target cells within the cochlea. This could provide the means for a one-time treatment to promote long-term NT expression and improve neural survival after deafness. This review summarizes the evidence for the efficacy of exogenous NTs in preventing SGN degeneration after hearing loss and reviews the animal research to date suggesting that NT gene therapy can elicit long-term NT expression in the cochlea, resulting in significantly improved SGN and radial nerve fiber survival after deafness. In addition, we discuss NT gene therapy in other non-auditory applications and consider some of the remaining issues with regard to selecting optimal vectors, timing of treatment, and place/method of delivery, etc. that must be resolved prior to considering clinical application.
Subject(s)
Deafness , Animals , Brain-Derived Neurotrophic Factor/genetics , Deafness/genetics , Deafness/therapy , Genetic Therapy , Humans , Neurons , Neurotrophin 3/genetics , Spiral GanglionABSTRACT
BACKGROUND: Neurotrophin-3 (NT-3), a member of the NT family, has only been considered an ancillary compound that provides anti-apoptotic benefits by inactivating tropomyosin receptor kinase C (TrkC)-induced apoptotic signals. However, little is known about the clinical relevance of NT-3 expression itself in neuroblastoma. The purpose of this study was to assess NT-3 expression in patients with neuroblastoma and its relevance to clinicopathologic findings and treatment outcomes. METHODS: In this study, expression of NT-3 and TrkC was analyzed using immunohistochemistry in 240 patients with newly diagnosed neuroblastoma. RESULTS: The results of the study revealed that NT-3 expression was associated with older age at diagnosis, localized tumors, and more differentiated tumors but was not associated with early treatment response (degree of residual tumor volume after three cycles of chemotherapy) and progression-free survival (PFS). However, when analysis was confined to patients with MYCN amplified tumors, NT-3 expression was associated with better early treatment response with borderline significance (P = 0.092) and higher PFS (86.9% vs. 58.2%; P = 0.044). In multivariate analysis in patients with MYCN amplified tumors, NT-3 was independent prognostic factor (hazard ratio, 0.246; 95% confidence interval, 0.061-0.997; P = 0.050). In another subgroup analysis, the early treatment response was better if NT-3 was expressed in patients without TrkC expression (P = 0.053) while it was poorer in patients with TrkC expression (P = 0.023). CONCLUSION: This study suggests that NT-3 expression in neuroblastoma has its own clinical significance independent of TrkC expression, and its prognostic significance differs depending on the status of MYCN amplification and/or TrkC expression.
Subject(s)
N-Myc Proto-Oncogene Protein/metabolism , Neuroblastoma/diagnosis , Neurotrophin 3/metabolism , Receptor, trkC/metabolism , Adolescent , Antineoplastic Agents/therapeutic use , Child , Child, Preschool , Female , Humans , Immunohistochemistry , Infant , Infant, Newborn , Male , N-Myc Proto-Oncogene Protein/genetics , Neoplasm Staging , Neuroblastoma/drug therapy , Neuroblastoma/pathology , Neurotrophin 3/genetics , Prognosis , Progression-Free Survival , Proportional Hazards Models , Real-Time Polymerase Chain Reaction , Receptor, trkC/geneticsABSTRACT
BACKGROUND: The attainment of extensive neurological function recovery remains the key challenge for the treatment of traumatic brain injury (TBI). Transplantation of bone marrow-derived mesenchymal stem cells (BMSCs) has been shown to improve neurological function recovery after TBI. However, the survival of BMSCs after transplantation in early-stage TBI is limited, and much is unknown about the mechanisms mediating this neurological function recovery. Secretion of neurotrophic factors, including neurotrophin 3 (NT3), is one of the critical factors mediating BMSC neurological function recovery. Gene mutation of NT3 (NT3P75-2) has been shown to enhance the biological function of NT3 via the reduction of the activation of the P75 signal pathway. Thus, we investigated whether NT3P75-2 gene-modified BMSCs could enhance the survival of BMSCs and further improve neurological function recovery after TBI. METHODS: The ability of NT3P75-2 induction to improve cell growth rate of NSC-34 and PC12 cells in vitro was first determined. BMSCs were then infected with three different lentiviruses (green fluorescent protein (GFP), GFP-NT3, or GFP-NT3P75-2), which stably express GFP, GFP-NT3, or GFP-NT3P75-2. At 24 h post-TBI induction in mice, GFP-labeled BMSCs were locally transplanted into the lesion site. Immunofluorescence and histopathology were performed at 1, 3, and/or 7 days after transplantation to evaluate the survival of BMSCs as well as the lesion volume. A modified neurological severity scoring system and the rotarod test were chosen to evaluate the functional recovery of the mice. Cell growth rate, glial activation, and signaling pathway analyses were performed to determine the potential mechanisms of NT3P75-2 in functional recovery after TBI. RESULTS: Overall, NT3P75-2 improved cell growth rate of NSC-34 and PC12 cells in vitro. In addition, NT3P75-2 significantly improved the survival of transplanted BMSCs and neurological function recovery after TBI. Overexpression of NT3P75-2 led to a significant reduction in the activation of glial cells, brain water content, and brain lesion volume after TBI. This was associated with a reduced activation of the p75 neurotrophin receptor (P75NTR) and the c-Jun N-terminal kinase (JNK) signal pathway due to the low affinity of NT3P75-2 for the receptor. CONCLUSIONS: Taken together, our results demonstrate that administration of NT3P75-2 gene-modified BMSCs dramatically improves neurological function recovery after TBI by increasing the survival of BMSCs and ameliorating the inflammatory environment, providing a new promising treatment strategy for TBI.
Subject(s)
Bone and Bones/cytology , Brain Injuries, Traumatic/physiopathology , Brain Injuries, Traumatic/therapy , Mesenchymal Stem Cells/metabolism , Neurotrophin 3/genetics , Neurotrophin 3/therapeutic use , Recovery of Function , Animals , Brain Edema/etiology , Brain Edema/therapy , Brain Injuries, Traumatic/complications , Cell Line , Cell Proliferation , Cell Survival , Disease Models, Animal , Humans , Male , Mesenchymal Stem Cell Transplantation , Mice , Neuroglia/metabolism , Rats , Receptor, trkC/metabolism , Signal TransductionABSTRACT
Noise exposures causing only transient threshold shifts can destroy auditory-nerve synapses without damaging hair cells. Here, we asked whether virally mediated neurotrophin3 (NT3) overexpression can repair this damage. CBA/CaJ mice at 6 wks were injected unilaterally with adeno-associated virus (AAV) containing either NT3 or GFP genes, via the posterior semicircular canal, 3 wks prior to, or 5 hrs after, noise exposure. Controls included exposed animals receiving vehicle only, and unexposed animals receiving virus. Thresholds were measured 2 wks post-exposure, just before cochleas were harvested for histological analysis. In separate virus-injected animals, unexposed cochleas were extracted for qRT-PCR. The GFP reporter showed that inner hair cells (IHCs) were transfected throughout the cochlea, and outer hair cells mainly in the apex. qRT-PCR showed 4- to 10-fold overexpression of NT3 from 1-21 days post-injection, and 1.7-fold overexpression at 40 days. AAV-NT3 delivered prior to noise exposure produced a dose-dependent reduction of synaptopathy, with nearly complete rescue at some cochlear locations. In unexposed ears, NT3 overexpression did not affect thresholds, however GFP overexpression caused IHC loss. In exposed ears, NT3 overexpression increased permanent threshold shifts. Thus, although NT3 overexpression can minimize noise-induced synaptic damage, the forced overexpression may be harmful to hair cells themselves during cochlear overstimulation.
Subject(s)
Cochlea/pathology , Dependovirus/metabolism , Neurotrophin 3/metabolism , Noise , Synapses/pathology , Animals , Auditory Threshold , Cochlea/physiopathology , Evoked Potentials, Auditory, Brain Stem , Green Fluorescent Proteins/metabolism , Hair Cells, Auditory, Inner/metabolism , Hair Cells, Auditory, Inner/pathology , Hair Cells, Auditory, Outer/metabolism , Hair Cells, Auditory, Outer/pathology , Male , Mice, Inbred C57BL , Mice, Inbred CBA , Neurotrophin 3/genetics , Otoacoustic Emissions, Spontaneous , RNA, Messenger/genetics , RNA, Messenger/metabolism , Synapses/metabolismABSTRACT
BACKGROUND: An early-life anxious temperament (AT) is a risk factor for the development of anxiety, depression, and comorbid substance abuse. We validated a nonhuman primate model of early-life AT and identified the dorsal amygdala as a core component of AT's neural circuit. Here, we combine RNA sequencing, viral-vector gene manipulation, functional brain imaging, and behavioral phenotyping to uncover AT's molecular substrates. METHODS: In response to potential threat, AT and brain metabolism were assessed in 46 young rhesus monkeys. We identified AT-related transcripts using RNA-sequencing data from dorsal amygdala tissue (including central nucleus of the amygdala [Ce] and dorsal regions of the basal nucleus). Based on the results, we overexpressed the neurotrophin-3 gene, NTF3, in the dorsal amygdala using intraoperative magnetic resonance imaging-guided surgery (n = 5 per group). RESULTS: This discovery-based approach identified AT-related alterations in the expression of well-established and novel genes, including an inverse association between NTRK3 expression and AT. NTRK3 is an interesting target because it is a relatively unexplored neurotrophic factor that modulates intracellular neuroplasticity pathways. Overexpression of the transcript for NTRK3's endogenous ligand, NTF3, in the dorsal amygdala resulted in reduced AT and altered function in AT's neural circuit. CONCLUSIONS: Together, these data implicate neurotrophin-3/NTRK3 signaling in the dorsal amygdala in mediating primate anxiety. More generally, this approach provides an important step toward understanding the molecular underpinnings of early-life AT and will be useful in guiding the development of treatments to prevent the development of stress-related psychopathology.