Traumatic brain injury(TBI)is the main cause of disability,mental health disorder,and even death,with its incidence and social costs rising steadily.Although different treatment strategies have been developed and test...Traumatic brain injury(TBI)is the main cause of disability,mental health disorder,and even death,with its incidence and social costs rising steadily.Although different treatment strategies have been developed and tested to mitigate neurological decline,a definitive cure for these conditions remains elusive.Studies have revealed that vari-ous neurotrophins represented by the brain-derived neurotrophic factor are the key regulators of neuroinflammation,apoptosis,blood-brain barrier permeability,neurite regeneration,and memory function.These factors are instrumental in alleviating neu-roinflammation and promoting neuroregeneration.In addition,neural stem cells(NSC)contribute to nerve repair through inherent neuroprotective and immunomodulatory properties,the release of neurotrophins,the activation of endogenous NSCs,and in-tercellular signaling.Notably,innovative research proposals are emerging to combine BDNF and NSCs,enabling them to synergistically complement and promote each other in facilitating injury repair and improving neuron differentiation after TBI.In this review,we summarize the mechanism of neurotrophins in promoting neurogen-esis and restoring neural function after TBI,comprehensively explore the potential therapeutic effects of various neurotrophins in basic research on TBI,and investigate their interaction with NSCs.This endeavor aims to provide a valuable insight into the clinical treatment and transformation of neurotrophins in TBI,thereby promoting the progress of TBI therapeutics.展开更多
Objective Cloning and sequencing of the human neurotrophin 4 gene.Methods With the chromosomal DNA of human blood lymphocytes as template,hNT 4 coding genes were amplified by polymerase chain reaction and recombinated...Objective Cloning and sequencing of the human neurotrophin 4 gene.Methods With the chromosomal DNA of human blood lymphocytes as template,hNT 4 coding genes were amplified by polymerase chain reaction and recombinated into phage vector pGEM T Easy,which were sequenced by using Sanger’s single stranded DNA terminal termination method.Results The sequence of the cloned gene is completely the same as that reported in the literature.Conclusion This study successfully cloning and sequenced the gene of mhNT 4,and it would be convenient for us to study the expression of mhNT 4 in eukaryote,and to continue the research on the gene therapy of Alzheimer’s disease intensively.This study indicate that the hNT 4 is conservative in different races and individuals.展开更多
Brain-derived neurotrophic factor(BDNF),a critical neurotrophin,regulates many neuronal aspects including cell differentiation,cell survival,neurotransmission,and synaptic plasticity in the central nervous system(CNS)...Brain-derived neurotrophic factor(BDNF),a critical neurotrophin,regulates many neuronal aspects including cell differentiation,cell survival,neurotransmission,and synaptic plasticity in the central nervous system(CNS) .Though BDNF has two types of receptors,high affinity tropomyosin-related kinase(Trk) B and low affinity p75 receptors,BDNF positively exerts its biological effects on neurons via activation of TrkB and of resultant intracellular signaling cascades including mitogenactivated protein kinase/extracellular signal-regulated protein kinase,phospholipase Cγ,and phosphoinositide 3-kinase pathways.Notably,it is possible that alteration in the expression and/or function of BDNF in the CNS is involved in the pathophysiology of various brain diseases such as stroke,Parkinson's disease,Alzheimer's disease,and mental disorders.On the other hand,glucocorticoids,stress-induced steroid hormones,also putatively contribute to the pathophysiology of depression.Interestingly,in addition to the reduction in BDNF levels due to increased glucocorticoid exposure,current reports demonstrate possible interactions between glucocorticoids and BDNF-mediated neuronal functions. Other steroid hormones,such as estrogen,are involved in not only sexual differentiation in the brain,but also numerous neuronal events including cell survival and synaptic plasticity.Furthermore,it is well known that estrogen plays a role in the pathophysiology of Parkinson's disease,Alzheimer's disease,and mental illness,while serving to regulate BDNF expression and/or function.Here,we present a broad overview of the current knowledge concerning the association between BDNF expression/function and steroid hormones(glucocorticoids and estrogen).展开更多
BACKGROUND： Previous studies have shown that p75 neurotrophin receptor plays an important role in peripheral nerve injury. However, the role of p75 neurotrophin receptor in the regeneration of peripheral nerves remai...BACKGROUND： Previous studies have shown that p75 neurotrophin receptor plays an important role in peripheral nerve injury. However, the role of p75 neurotrophin receptor in the regeneration of peripheral nerves remains poorly understood. OBJECTIVE： To study the effect of p75 neurotrophin receptor on facial nerve regeneration. DESIGN, TIME AND SETTING： A randomized controlled experiment was performed in the Regeneration Laboratory of Flinders University, Australia and the Biomedical Laboratory of Dentistry School, Shandong University from March 2005 to February 2006. MATERIALS： Cholera toxin B subunit, fast blue, and biotin rabbit-anti goat IgG were provided by Sigma, USA; goat-anti choleratoxin B subunit ant/body was provided by List Biologicals, USA. METHODS： In p75 neurotrophin receptor knockout and wild type 129/sv mice, the facial nerves on one side were crushed. At days 2 and 4 following injury, regenerating motor neurons in the facial nuclei were labeled by fast blue, and the regenerating axon was labeled by the anterograde tracer choleratoxin B subunit. MAIN OUTCOME MEASURES： Axonal regenerative velocity and number were detected by immunohistochemical staining of choleratoxin B subunit, growth-associated protein, protein gene product 9.5, and calcitonin-gene-related peptide; survival of motor neurons in the facial nuclei was detected by retrograde fast blue. RESULTS： Axonal growth in the facial nerve of p75 neurotrophin receptor knockout mice was significantly less than in wild type mice. At day 7 after injury, the number of regenerating motor neurons in p75 neurotrophin receptor knockout mice remained significantly less than in wild type mice （P 〈 0.05）. The number of positively stained fibers for growth-associated protein-43, protein gene product 9.5, and calcitonin-gene-related peptide in p75 neurotrophin receptor knockout mice was significantly less than in wild type mice （P 〈 0.01）. CONCLUSION： p75 neurotrophin receptor promoted axonal regeneration and enhanced the survival rate of motor neurons following facial nerve injury.展开更多
BACKGROUND： Many methods have been attempted to repair nerves following spinal cord injury, including peripheral nerve transplantation, Schwann cell transplantation, olfactory ensheathing cell transplantation, and em...BACKGROUND： Many methods have been attempted to repair nerves following spinal cord injury, including peripheral nerve transplantation, Schwann cell transplantation, olfactory ensheathing cell transplantation, and embryonic neural tissue transplantation. However, there is a need for improved outcomes. OBJECTIVE： To investigate the repair feasibility for rat spinal cord injury using human neural stem cells （hNSCs） genetically modified by lentivirus to express neurotrophin-3. DESIGN, TIME AND SETTING： In vitro cell biological experiment and in vivo randomized, controlled genetic engineering experiment were performed at the Third Military Medical University of Chinese PLA and First People＇s Hospital of Yibin, China from March 2006 to December 2007. MATERIALS： A total of 64 adult, female, Wistar rats were used for the in vivo study. Of them, 48 rats were used to establish models of spinal cord hemisection, and were subsequently equally and randomly assigned to model, genetically modified hNSC, and normal hNSC groups. The remaining 16 rats served as normal controls. METHODS： hNSCs were in vitro genetically modified by lentivirus to secrete both green fluorescence protein and neurotrophin-3. Neurotrophin-3 expression was measured by Western blot. Genetically modified hNSC or normal hNSC suspension （5 × 10^5） was injected into the rat spinal cord following T10 spinal cord hemisection. A total of 5μL Dulbecco＇s-modified Eagle＇s medium was infused into the rat spinal cord in the model grop. Transgene expression and survival of transplanted hNSCs were determined by immunohistochemistry. Motor function was evaluated using the Basso, Beattie, and Bresnahan （BBB） scale. MAIN OUTCOME MEASURES： The following parameters were measured： expression of neurotrophin-3 produced by genetically modified hNSCs, transgene expression and survival of hNSCs in rats, motor function in rats. RESULTS： hNSCs were successfully genetically modified by lentivirus to stably express neurotrophin-3. The transplanted hNSCs primarily gathered at, or around, the injection site two weeks following transplantation, and gradually migrated towards the surrounding tissue. Transplanted hNSCs were observed 7.0-8.0 mm away from the injection site. In addition, hNSCs were observed 10 weeks after transplantation. At week 4, BBB locomotor scores were significantly greater in the genetically modified hNSC and normal hNSC groups, compared with the model group （P 〈 0.05）, and scores were significantly greater in the genetically modified hNSC group compared with the normal hNSC group （P 〈 0.05）. CONCLUSION： hNSCs were genetically modified with lentivirus to stably secrete neurotrophin-3. hNSCs improved motor function recovery in rats following spinal cord injury.展开更多
The many important benefits of physical exercise also encompass maintenance or improvement of cognitive functions. Among the variousmechanisms underlying the association between physical exercise and brain health, rec...The many important benefits of physical exercise also encompass maintenance or improvement of cognitive functions. Among the variousmechanisms underlying the association between physical exercise and brain health, recent evidence attests that neurotrophin receptor signalingmay have an important role, because the activation of this pathway leads to growth and differentiation of new neurons and synapses, supportsaxonal and dendritic growth, fosters synaptic plasticity, and preserves survival of existing neurons. In this review of published evidence, we highlightthat a positive relationship exists between physical exercise and circulating brain-derived neurotrophic factor levels and that the postexercisevariation of this molecule is associated with improvement of neurocognitive functioning. Less clear evidence has instead been published forother neurotrophins, such as nerve growth factor, neurotrophin-3, and neurotrophin-4. Overall, promotion of adequate volumes and intensities ofphysical exercise (i.e., approximately 3 months of moderate-intensity aerobic exercise, with 2—3 sessions/week lasting not less than 30 min)may hence be regarded as an inexpensive and safe strategy for boosting brain-derived neurotrophic factor release, thus preserving or restoringcognitive functions.展开更多
Neurotrophins (NTs) are implicated in the maintenance and survival of the peripheral and central nervous systems and mediate several forms of synaptic plasticity. Members of the family include nerve growth factor (NGF...Neurotrophins (NTs) are implicated in the maintenance and survival of the peripheral and central nervous systems and mediate several forms of synaptic plasticity. Members of the family include nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), NT3, and NT4. NTs were first identified as survival factors for developing neurons, but are pleiotropic molecules that can exert a variety of functions, including the regulation of neuronal differentiation, axonal and dendritic growth, and synaptic plasticity (Bothwell, 2014). NTs interact with two distinct types of receptors: the common p75 neurotrophin receptor, which belongs to the tumor necrosis factor receptor superfamily of death receptors and the Trk receptor tyrosine kinase family.展开更多
BACKGROUND： Recent studies have suggested that regeneration of the central nerve fiber following spinal cord injury occurs under specific conditions. OBJECTIVE： To study the effects of Nogo-neutralizing antibody （...BACKGROUND： Recent studies have suggested that regeneration of the central nerve fiber following spinal cord injury occurs under specific conditions. OBJECTIVE： To study the effects of Nogo-neutralizing antibody （IN-1）, in combination with neurotrophin-3 （NT-3）, on axonal regeneration and motor function following spinal cord injury in the rat. DESIGN, TIME AND SETTING： A randomized, controlled, animal study combining immunohistochemistry was performed at the Laboratory of Neuroanatomy of Xiangya Medical College, and Central Laboratory of Xiangya the Third Hospital, Central South University from January 2006 to December 2007. MATERIALS： Eighteen healthy, Sprague Dawley rats were randomly divided into three groups, with six rats per group： control, IN-l, and IN-1/NT-3. Hemisectioned spinal cord injury models were established by cutting the posterior 2/3 of spinal cord, which is equivalent to the Ts level. METHODS： A polyethylene tubing was inserted through into subarachnoid cavity, equivalent to the superior margin at the T8 level. Saline, IN-1, and IN-1/NT-3 were respectively injected into control, IN-1, and IN-1/NT-3 groups, three times/day for seven consecutive days. MAIN OUTCOME MEASURES： At 2 weeks post-surgery, biotin dextran amine （10%） was injected into the right sensorimotor cortex area. At day 28 post-surgery, spinal cord tissue was prepared for frozen sections Positive astrocytic expression was observed with glial fibrillary acidic protein （GFAP） immunohistochemical staining whose proliferation level was represented by gray value, i.e. the higher the gray value was, the less the positive cells were, and growth of positive fibers was observed with a biotin dextran amine histological reaction. Motor function was measured according to BBB scores pre-operatively, as well as at days 1, 7, 14, 21, and 28 post-operatively. RESULTS： Three rats died during experimentation. By random supplement, a total of 18 rats were included. GFAP-positive astrocytes were observed in all the three groups. In the control group, astrocytes were characterized according to active function, hyperplasia, proliferation, hypertrophy, and increasing processes as compared to IN-1 group and IN-1/IN-3 group. Astrocyte hyperplasia represented by gray value in the IN-1 group was less than the control group. Gray value of GFAP-positive products in the IN-1/IN-3 group was higher than other two groups （P 〈 0.05）. Biotin dextran amine tracing demonstrated no corticospinal tract fiber outgrowth following spinal cord injury; the fibers were incapable of passing through the glial scar in the control group. Several fibers were distributed in the proximal scar tissue region in the IN-1 group, and the regenerated fibers were disarranged. Many nerve fibers were distributed throughout the scar tissue, and even several biotin dextran amine-positive fibers were observed at the distal end of the injured segment. Post-operative Basso, Beattie, Bresnahan scores were greater than pre-operative ones, while Basso, Beattie, Bresnahan scores in the IN-1/NT-3 group were significantly greater than the other two groups at days 14, 21, and 28 post-surgery （P 〈 0.05）. CONCLUSION： IN-1, in combination with NT-3, promoted axonal regeneration following spinal cord injury, inhibited the colloidal effect, and enhanced the correlation between proximal and distal processes to recover motor function. The recovery effect of IN-1/NT-3 on motor function was superior that of to IN-1 alone.展开更多
The role of neurotrophins in neuronal plasticity has recently become a strong focus in neuroregeneration research field to elucidate the biological mechanisms by which these molecules modulate synapses,modify the resp...The role of neurotrophins in neuronal plasticity has recently become a strong focus in neuroregeneration research field to elucidate the biological mechanisms by which these molecules modulate synapses,modify the response to injury,and alter the adaptation response.Intriguingly,the prior studies highlight the role of p75 neurotrophin receptor(p75^(NTR))in various injuries and diseases such as central nervous system injuries,Alzheimer's disease and amyotrophic lateral sclerosis.More comprehensive elucidation of the mechanisms,and therapies targeting these molecular signaling networks may allow for neuronal tissue regeneration following an injury.Due to a diverse role of the p75^(NTR)in biology,the body of evidence comprising its biological role is diffusely spread out over numerous fields.This review condenses the main evidence of p75^(NTR)for clinical applications and presents new findings from published literature how data mining approach combined with bioinformatic analyses can be utilized to gain new hypotheses in a molecular and network level.展开更多
Bone marrow mesenchymal stem cell transplantation has been shown to be therapeutic in the repair of spinal cord injury. However, the low survival rate of transplanted bone marrow mesen- chymal stem cells in vivo remai...Bone marrow mesenchymal stem cell transplantation has been shown to be therapeutic in the repair of spinal cord injury. However, the low survival rate of transplanted bone marrow mesen- chymal stem cells in vivo remains a problem. Neurotrophin-3 promotes motor neuron survival and it is hypothesized that its transfection can enhance the therapeutic effect. We show that in vitro transfection of neurotrophin-3 gene increases the number of bone marrow mesenchymal stem cells in the region of spinal cord injury. These results indicate that neurotrophin-3 can promote the survival of bone marrow mesenchymal stem cells transplanted into the region of spinal cord injury and potentially enhance the therapeutic effect in the repair of spinal cord injury.展开更多
This manuscript reviews the function and fundamental characteristics of the neurotrophins and their receptors to introduce the reader to the differential effects exhibited by the neurotrophins;brain-derived neurotroph...This manuscript reviews the function and fundamental characteristics of the neurotrophins and their receptors to introduce the reader to the differential effects exhibited by the neurotrophins;brain-derived neurotrophic factor and neurotrophin 4/5 when acted together after sequential presentation.The neurotrophin 4/5 exhibits an inhibitory action on the modulatory effect of brain-derived neurotrophic factor in corticostriatal synapses when they are administered sequentially(brain-derived neurotrophic factor to neurotrophin 4/5).This inhibitory effect has not been previously documented and is relevant for these neurotrophins as both of them stimulate the TrkB receptor.The additive effect of these neurotrophins is also discussed and occurs when neurotrophin 4/5 exposure is followed by brain-derived neurotrophic factor in a mouse model of striatal degeneration.Occlusive and additive effects of both neurotrophins are accompanied by changes in the expression of the TrkB receptor isoforms,specifically TrkB-T1 and TrkB-FL,as well as differences in phosphorylation levels of the TrkB receptor.The results of the experiments described raise several questions to inquire about the role that TrkB-T1 receptor plays in striatal physiology,as well as the functional relevance of the interaction of brain-derived neurotrophic factor and neurotrophin 4/5 in the brain and more specifically at the striatal circuits in normal as well as pathological conditions.展开更多
Schwann ceils and neurotrophin-3 play an important role in neural regeneration, but the secretion of neurotrophin-3 from Schwann cells is limited, and exogenous neurotrophin-3 is inactived easily in vivo. In this stud...Schwann ceils and neurotrophin-3 play an important role in neural regeneration, but the secretion of neurotrophin-3 from Schwann cells is limited, and exogenous neurotrophin-3 is inactived easily in vivo. In this study, we have transfected neurotrophin-3 into Schwann cells cultured in vitro using nanoparticle liposomes. Results showed that neurotrophin-3 was successfully transfected into Schwann cells, where it was expressed effectively and steadily. A composite of Schwann cells transfected with neurotrophin-3 and poly（lactic-co-glycolic acid） biodegradable conduits was transplanted into rats to repair 10-mm sciatic nerve defects. Transplantation of the composite scaffold could restore the myoelectricity and wave amplitude of the sciatic nerve by electrophysiological examination, promote nerve axonal and myelin regeneration, and delay apoptosis of spinal motor neurons. Experimental findings indicate that neurotrophin-3 transfected Schwann cells combined with bridge grafting can promote neural regeneration and functional recovery after nerve injury.展开更多
BACKGROUND： Studies have demonstrated that cauda equina compression results in apoptosis of motor neurons in the spinal cord. The combination of p75 neurotrophin receptor （p75NTR） and precursor of nerve growth fact...BACKGROUND： Studies have demonstrated that cauda equina compression results in apoptosis of motor neurons in the spinal cord. The combination of p75 neurotrophin receptor （p75NTR） and precursor of nerve growth factor （pro-NGF） expression initiates the apoptotic pathway and induces neuronal apoptosis. However, few reports have focused on the p75-mediated mechanism of neuronal apoptosis following cauda equine compression injury OBJECTIVE： To determine apoptosis of spinal cord neurons and activation of the pro-NGF-p75NTR-JNK（c-Jun N-terminal kinase） signal pathway in rats following cauda equina compression, and to verify experimental outcomes. DESIGN, TIME AND SETTING： A randomized, controlled, in vivo experiment was performed at the Medical Experimental Center of Xi＇an Jiaotong University between April and November in 2008. MATERIALS： Streptavidin-perosidase kit was purchased from Wuhan Boster, China; in situ end labeling detection kit was provided by Promega, USA; type AEG-220G electron microscope was purchased from Hitachi, Japan. METHODS： A total of 48 healthy, adult, female, Sprague Dawley rats were randomly assigned to three groups： normal （n = 6）, sham-surgery （n = 6）, and compression （n = 36）. The compression group was randomly assigned to six subsets at 1,3, 5, 7, 14, and 28 days, respectively, with 6 rats in each subset. A cylindrical silica gel stick was implanted into the rats to compress 75% of the vertebral canal in the compression group; in the sham-surgery group, only vertebral resection was performed; and no procedures were performed in the normal group. MAIN OUTCOME MEASURES： At 1,3, 5, 7, 14, and 28 days following compression, L2-3 spinal cord segments were processed for immunohistochemistry, in situ cell apoptosis detection, and transmission electron microscopy observation. Nissl staining was used to observe neuronal survival in the L2 spinal cord segment. Immunohistochemistry was applied to detect expressions of pro-NGF, p75NTR, and JNK in the L2 segment. TUNEL fluorometric method was used to observe apoptosis of neurons in the L2 segment. RESULTS： In the normal and sham-surgery groups, little neuronal apoptosis was observed in the L2-3 spinal cord segment. At 3 days after compression injury, pro-NGF, p75NTR and JNK expression was observed in the spinal cord. Expression levels reached a peak at 7 days, and then gradually decreased. In the compression and sham-surgery groups, neurons primarily expressed pro-NGF and p75NTR. The number of JNK-positive neurons in the compression group was dramatically increased compared with the sham-surgery group （P〈 0.05）. A few neurons were apoptotic in the spinal cord 1 day after compression injury. The number of apoptotic neurons gradually increased and reached a peak at 7 days, and subsequently decreased. Apoptosis was still detectable at 28 days. There was a positive correlation between p75NTR expression and neuronal apoptosis （r= 0.75, P〈 0.05）. CONCLUSION： Following cauda equina compression injury, apoptosis of spinal cord neurons was observed. The compression-induced neuronal apoptosis was associated with p75NTR expression in the L2-3 spinal cord segment.展开更多
This study demonstrated that brain areas surrounding the site of hematoma following intracerebral hemorrhage are characterized by significantly increased apoptosis and expression of neurotrophin receptor p75 and sorti...This study demonstrated that brain areas surrounding the site of hematoma following intracerebral hemorrhage are characterized by significantly increased apoptosis and expression of neurotrophin receptor p75 and sortilin. However, as detected by terminal deoxynucleotidyl transferase dUTP nick end labeling and immunohistochemical staining, there was no significant change in nerve growth factor precursor expression levels. The appearance of neurotrophin receptor p75 expressing cells was positively correlated with cells that were detected by terminal deoxynucleotidyl transferase dUTP nick end labeling. These findings confirm that the nerve growth factor precursor-neurotrophin receptor p75-sortilin heterotrimeric complex-mediated apoptosis pathway may play an important role in cellular apoptosis following intracerebral hemorrhage.展开更多
BACKGROUND： Nogo-neutralizing antibody IN-1 accelerates axon growth and enhances recovery of spinal cord function by inhibiting growth inhibitory factors. Neurotrophin-3 （NT-3）contributes to regeneration of nerve f...BACKGROUND： Nogo-neutralizing antibody IN-1 accelerates axon growth and enhances recovery of spinal cord function by inhibiting growth inhibitory factors. Neurotrophin-3 （NT-3）contributes to regeneration of nerve fibers in the spinal cord and motor function recovery. The combination of Nogo-neutralizing antibody IN-1 and NT-3 is hypothesized to produce better outcomes and facilitate axonal regeneration by affecting c-Fos and c-Jun protein expression. OBJECTIVE： To investigate the combined effects of Nogo-neutralizing antibody IN-1 and NT-3 on c-Fos and c-Jun protein levels in the injured spinal cord. DESIGN, TIME AND SETTING： A randomized, controlled study was performed at the Laboratory of Neuroanatomy, Xiangya Medical College, Central South University and the Central Laboratory of Third Xiangya Hospital of China from June 2005 to December 2007. MATERIALS： NT-3 （Peprotech, USA） and Nogo-neutralizing antibody IN-1 （Santa Cruz Biotechnology, USA） were used in this study. METHODS： Hemisectioned spinal cord injury models were established by cutting the posterior 2/3 of rat spinal cord, which is equivalent to the T8 level in the human spine. A total of 120 rats were equally and randomly assigned to three groups： model （0.2 μL saline）, IN-1 （0.2 μL IN-1）, and IN-1/NT-3 （0.2 μL IN-1 ＋ 0.2 μL NT-3）. The compounds were separately infused into transection sites on the side of head. MAIN OUTCOME MEASURES： Western blot analysis was employed to measure c-Fos and c-Jun protein expression in the injured spinal cord at 15, 30 minutes, 1,2, 4, 6, 8, and 12 hours following surgery. RESULTS： Following spinal cord injury, c-Fos and c-Jun protein expression were increased and peaked at 4 6 hours. Following injection of IN-1 or the combination of IN-1 and NT-3, c-Fos protein expression was significantly reduced in the injured spinal cord （P 〈 0.05 or P 〈 0.01） （with the exception of the 15 minute time point）. However, c-Jun protein expression was significantly increased （P〈 0.05 or P〈 0.01） （with the exception of the 15 and 30 minute time points）. Combined application of IN-1 and NT-3 resulted in significantly altered protein expression compared to IN-1 alone. CONCLUSION： IN-1 increases c-Jun protein levels and protects the injured spinal cord by inhibiting c-Fos protein levels. Moreover, the effects of IN-1 combined with NT-3 are more significant than with IN-1 alone.展开更多
In the present study, we investigated the role of endogenous neurotrophin-3 in nerve terminal sprouting 2 months after spinal cord dorsal root rhizotomy. The left L1-5 and L7-S2 dorsal root ganglia in adult cats were ...In the present study, we investigated the role of endogenous neurotrophin-3 in nerve terminal sprouting 2 months after spinal cord dorsal root rhizotomy. The left L1-5 and L7-S2 dorsal root ganglia in adult cats were exposed and removed, preserving the L6 dorsal root ganglia. Neurotrophin-3 was mainly expressed in large neurons in the dorsal root ganglia and in some neurons in spinal lamina II. Two months after rhizotomy, the number of neurotrophin-3-positive neurons in the spared dorsal root ganglia and the density of neurite sprouts emerging from these ganglia were increased. Intraperitoneal injection of an antibody against neurotrophin-3 decreased the density of neurite sprouts. These findings suggest that endogenous neurotrophin-3 is involved in spinal cord plasticity and regeneration, and that it promotes axonal sprouting from the dorsal root ganglia after spinal cord dorsal root rhizotomy.展开更多
Neurotrophic factors are able to promote neuronalsurvival and prevent neuronal death induced by variousinjuries and have potential uses in the treatment ofneuronal degenerative diseases and neuropathy. Due tothe exist...Neurotrophic factors are able to promote neuronalsurvival and prevent neuronal death induced by variousinjuries and have potential uses in the treatment ofneuronal degenerative diseases and neuropathy. Due tothe existence of brain blood barrier, neurotrophic factorscan not be ased in CNS diseases directly. Gene therapy isa good candidate to overcome this problem.展开更多
Neurotrophin-3 （NT-3） can promote the repair of central nervous system and retinal damage. In previous reports, NT-3 has been expressed by viral vectors. However, plasmid vectors have a safer profile compared with v...Neurotrophin-3 （NT-3） can promote the repair of central nervous system and retinal damage. In previous reports, NT-3 has been expressed by viral vectors. However, plasmid vectors have a safer profile compared with viral vectors in clinical studies. This study recombined amplified human retinal NT-3 with a eukaryotic expression plasmid containing green fluorescent protein （GFP） to construct an NT-3 expression plasmid, pEGFP-N1-NT-3. The transfection efficiency 48 hours after pEGFP-N1-NT-3 transfection to 293T cells was 50.06 ＋ 2.78%. Abundant NTo3-GFP was expressed in 293T cells as observed by fluorescence microscopy, suggesting the construct pEGFP-N1-NT-3 effectively expressed and secreted NT-3-GFP. Secretory vesicles containing NT-3-GFP were observed in a constant location in cells by laser scan confocal microscopy, indicating the expression and secretion processes of NT-3 in eukaryotic cells were in accordance with the physical synthesis processes of secreted proteins. Western blot assay showed that pro-NTo3-GFP had a molecular weight of 56 kDa, further confirming NT-3-GFP expression. At 48 hours after transfection, the concentration of NT-3 in culture medium was 22.3 ng/mL, suggesting NT-3 produced by pEGFP-N1-NT-3 was efficiently secreted. This study constructed a human retinal-derived NT-3 eukaryotic expression plasmid that efficiently expressed and secreted NT-3.展开更多
基金Laboratory Animal Foundation Program of Military,Grant/Award Number:SYDW[2018]01Promotion Plan of the Air Force Medical University,Grant/Award Number:2020SWAQ11Shaanxi Province Innovation Capability Support Plan,Grant/Award Number:2021PT-037。
文摘Traumatic brain injury(TBI)is the main cause of disability,mental health disorder,and even death,with its incidence and social costs rising steadily.Although different treatment strategies have been developed and tested to mitigate neurological decline,a definitive cure for these conditions remains elusive.Studies have revealed that vari-ous neurotrophins represented by the brain-derived neurotrophic factor are the key regulators of neuroinflammation,apoptosis,blood-brain barrier permeability,neurite regeneration,and memory function.These factors are instrumental in alleviating neu-roinflammation and promoting neuroregeneration.In addition,neural stem cells(NSC)contribute to nerve repair through inherent neuroprotective and immunomodulatory properties,the release of neurotrophins,the activation of endogenous NSCs,and in-tercellular signaling.Notably,innovative research proposals are emerging to combine BDNF and NSCs,enabling them to synergistically complement and promote each other in facilitating injury repair and improving neuron differentiation after TBI.In this review,we summarize the mechanism of neurotrophins in promoting neurogen-esis and restoring neural function after TBI,comprehensively explore the potential therapeutic effects of various neurotrophins in basic research on TBI,and investigate their interaction with NSCs.This endeavor aims to provide a valuable insight into the clinical treatment and transformation of neurotrophins in TBI,thereby promoting the progress of TBI therapeutics.
文摘Objective Cloning and sequencing of the human neurotrophin 4 gene.Methods With the chromosomal DNA of human blood lymphocytes as template,hNT 4 coding genes were amplified by polymerase chain reaction and recombinated into phage vector pGEM T Easy,which were sequenced by using Sanger’s single stranded DNA terminal termination method.Results The sequence of the cloned gene is completely the same as that reported in the literature.Conclusion This study successfully cloning and sequenced the gene of mhNT 4,and it would be convenient for us to study the expression of mhNT 4 in eukaryote,and to continue the research on the gene therapy of Alzheimer’s disease intensively.This study indicate that the hNT 4 is conservative in different races and individuals.
基金Supported by Research Grants for Nervous and Mental Disorders from the Ministry of Health,Labor and Welfare Health and Labor Sciences Research Grants (Research on Psychiatric and Neurological Diseases and Mental Health)+2 种基金Health and Labor Sciences Research Grants,a grant from the Japan Foundation for Neuroscience and Mental Healththe Program for Promotion of Fundamental Studies in Health Sciences of the National Institute of Biomedical Innovation (Kunugi H)a Grant-in-Aid for Young Scientists (A) (21680034) from the Ministry of Education,Culture,Sports,Science,and Technology of Japan (Numakawa T)
文摘Brain-derived neurotrophic factor(BDNF),a critical neurotrophin,regulates many neuronal aspects including cell differentiation,cell survival,neurotransmission,and synaptic plasticity in the central nervous system(CNS) .Though BDNF has two types of receptors,high affinity tropomyosin-related kinase(Trk) B and low affinity p75 receptors,BDNF positively exerts its biological effects on neurons via activation of TrkB and of resultant intracellular signaling cascades including mitogenactivated protein kinase/extracellular signal-regulated protein kinase,phospholipase Cγ,and phosphoinositide 3-kinase pathways.Notably,it is possible that alteration in the expression and/or function of BDNF in the CNS is involved in the pathophysiology of various brain diseases such as stroke,Parkinson's disease,Alzheimer's disease,and mental disorders.On the other hand,glucocorticoids,stress-induced steroid hormones,also putatively contribute to the pathophysiology of depression.Interestingly,in addition to the reduction in BDNF levels due to increased glucocorticoid exposure,current reports demonstrate possible interactions between glucocorticoids and BDNF-mediated neuronal functions. Other steroid hormones,such as estrogen,are involved in not only sexual differentiation in the brain,but also numerous neuronal events including cell survival and synaptic plasticity.Furthermore,it is well known that estrogen plays a role in the pathophysiology of Parkinson's disease,Alzheimer's disease,and mental illness,while serving to regulate BDNF expression and/or function.Here,we present a broad overview of the current knowledge concerning the association between BDNF expression/function and steroid hormones(glucocorticoids and estrogen).
基金the Natural Science Foundation of Shandong Province,No. Y2008C54
文摘BACKGROUND： Previous studies have shown that p75 neurotrophin receptor plays an important role in peripheral nerve injury. However, the role of p75 neurotrophin receptor in the regeneration of peripheral nerves remains poorly understood. OBJECTIVE： To study the effect of p75 neurotrophin receptor on facial nerve regeneration. DESIGN, TIME AND SETTING： A randomized controlled experiment was performed in the Regeneration Laboratory of Flinders University, Australia and the Biomedical Laboratory of Dentistry School, Shandong University from March 2005 to February 2006. MATERIALS： Cholera toxin B subunit, fast blue, and biotin rabbit-anti goat IgG were provided by Sigma, USA; goat-anti choleratoxin B subunit ant/body was provided by List Biologicals, USA. METHODS： In p75 neurotrophin receptor knockout and wild type 129/sv mice, the facial nerves on one side were crushed. At days 2 and 4 following injury, regenerating motor neurons in the facial nuclei were labeled by fast blue, and the regenerating axon was labeled by the anterograde tracer choleratoxin B subunit. MAIN OUTCOME MEASURES： Axonal regenerative velocity and number were detected by immunohistochemical staining of choleratoxin B subunit, growth-associated protein, protein gene product 9.5, and calcitonin-gene-related peptide; survival of motor neurons in the facial nuclei was detected by retrograde fast blue. RESULTS： Axonal growth in the facial nerve of p75 neurotrophin receptor knockout mice was significantly less than in wild type mice. At day 7 after injury, the number of regenerating motor neurons in p75 neurotrophin receptor knockout mice remained significantly less than in wild type mice （P 〈 0.05）. The number of positively stained fibers for growth-associated protein-43, protein gene product 9.5, and calcitonin-gene-related peptide in p75 neurotrophin receptor knockout mice was significantly less than in wild type mice （P 〈 0.01）. CONCLUSION： p75 neurotrophin receptor promoted axonal regeneration and enhanced the survival rate of motor neurons following facial nerve injury.
文摘BACKGROUND： Many methods have been attempted to repair nerves following spinal cord injury, including peripheral nerve transplantation, Schwann cell transplantation, olfactory ensheathing cell transplantation, and embryonic neural tissue transplantation. However, there is a need for improved outcomes. OBJECTIVE： To investigate the repair feasibility for rat spinal cord injury using human neural stem cells （hNSCs） genetically modified by lentivirus to express neurotrophin-3. DESIGN, TIME AND SETTING： In vitro cell biological experiment and in vivo randomized, controlled genetic engineering experiment were performed at the Third Military Medical University of Chinese PLA and First People＇s Hospital of Yibin, China from March 2006 to December 2007. MATERIALS： A total of 64 adult, female, Wistar rats were used for the in vivo study. Of them, 48 rats were used to establish models of spinal cord hemisection, and were subsequently equally and randomly assigned to model, genetically modified hNSC, and normal hNSC groups. The remaining 16 rats served as normal controls. METHODS： hNSCs were in vitro genetically modified by lentivirus to secrete both green fluorescence protein and neurotrophin-3. Neurotrophin-3 expression was measured by Western blot. Genetically modified hNSC or normal hNSC suspension （5 × 10^5） was injected into the rat spinal cord following T10 spinal cord hemisection. A total of 5μL Dulbecco＇s-modified Eagle＇s medium was infused into the rat spinal cord in the model grop. Transgene expression and survival of transplanted hNSCs were determined by immunohistochemistry. Motor function was evaluated using the Basso, Beattie, and Bresnahan （BBB） scale. MAIN OUTCOME MEASURES： The following parameters were measured： expression of neurotrophin-3 produced by genetically modified hNSCs, transgene expression and survival of hNSCs in rats, motor function in rats. RESULTS： hNSCs were successfully genetically modified by lentivirus to stably express neurotrophin-3. The transplanted hNSCs primarily gathered at, or around, the injection site two weeks following transplantation, and gradually migrated towards the surrounding tissue. Transplanted hNSCs were observed 7.0-8.0 mm away from the injection site. In addition, hNSCs were observed 10 weeks after transplantation. At week 4, BBB locomotor scores were significantly greater in the genetically modified hNSC and normal hNSC groups, compared with the model group （P 〈 0.05）, and scores were significantly greater in the genetically modified hNSC group compared with the normal hNSC group （P 〈 0.05）. CONCLUSION： hNSCs were genetically modified with lentivirus to stably secrete neurotrophin-3. hNSCs improved motor function recovery in rats following spinal cord injury.
基金supported by a postdoctoral contract granted by Subprograma Atraccio de Talent-Contractes Postdoctorals de la Universitat de Valencia
文摘The many important benefits of physical exercise also encompass maintenance or improvement of cognitive functions. Among the variousmechanisms underlying the association between physical exercise and brain health, recent evidence attests that neurotrophin receptor signalingmay have an important role, because the activation of this pathway leads to growth and differentiation of new neurons and synapses, supportsaxonal and dendritic growth, fosters synaptic plasticity, and preserves survival of existing neurons. In this review of published evidence, we highlightthat a positive relationship exists between physical exercise and circulating brain-derived neurotrophic factor levels and that the postexercisevariation of this molecule is associated with improvement of neurocognitive functioning. Less clear evidence has instead been published forother neurotrophins, such as nerve growth factor, neurotrophin-3, and neurotrophin-4. Overall, promotion of adequate volumes and intensities ofphysical exercise (i.e., approximately 3 months of moderate-intensity aerobic exercise, with 2—3 sessions/week lasting not less than 30 min)may hence be regarded as an inexpensive and safe strategy for boosting brain-derived neurotrophic factor release, thus preserving or restoringcognitive functions.
文摘Neurotrophins (NTs) are implicated in the maintenance and survival of the peripheral and central nervous systems and mediate several forms of synaptic plasticity. Members of the family include nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), NT3, and NT4. NTs were first identified as survival factors for developing neurons, but are pleiotropic molecules that can exert a variety of functions, including the regulation of neuronal differentiation, axonal and dendritic growth, and synaptic plasticity (Bothwell, 2014). NTs interact with two distinct types of receptors: the common p75 neurotrophin receptor, which belongs to the tumor necrosis factor receptor superfamily of death receptors and the Trk receptor tyrosine kinase family.
基金the Foundation of Hunan Public Health Bureau, No.B2005-076
文摘BACKGROUND： Recent studies have suggested that regeneration of the central nerve fiber following spinal cord injury occurs under specific conditions. OBJECTIVE： To study the effects of Nogo-neutralizing antibody （IN-1）, in combination with neurotrophin-3 （NT-3）, on axonal regeneration and motor function following spinal cord injury in the rat. DESIGN, TIME AND SETTING： A randomized, controlled, animal study combining immunohistochemistry was performed at the Laboratory of Neuroanatomy of Xiangya Medical College, and Central Laboratory of Xiangya the Third Hospital, Central South University from January 2006 to December 2007. MATERIALS： Eighteen healthy, Sprague Dawley rats were randomly divided into three groups, with six rats per group： control, IN-l, and IN-1/NT-3. Hemisectioned spinal cord injury models were established by cutting the posterior 2/3 of spinal cord, which is equivalent to the Ts level. METHODS： A polyethylene tubing was inserted through into subarachnoid cavity, equivalent to the superior margin at the T8 level. Saline, IN-1, and IN-1/NT-3 were respectively injected into control, IN-1, and IN-1/NT-3 groups, three times/day for seven consecutive days. MAIN OUTCOME MEASURES： At 2 weeks post-surgery, biotin dextran amine （10%） was injected into the right sensorimotor cortex area. At day 28 post-surgery, spinal cord tissue was prepared for frozen sections Positive astrocytic expression was observed with glial fibrillary acidic protein （GFAP） immunohistochemical staining whose proliferation level was represented by gray value, i.e. the higher the gray value was, the less the positive cells were, and growth of positive fibers was observed with a biotin dextran amine histological reaction. Motor function was measured according to BBB scores pre-operatively, as well as at days 1, 7, 14, 21, and 28 post-operatively. RESULTS： Three rats died during experimentation. By random supplement, a total of 18 rats were included. GFAP-positive astrocytes were observed in all the three groups. In the control group, astrocytes were characterized according to active function, hyperplasia, proliferation, hypertrophy, and increasing processes as compared to IN-1 group and IN-1/IN-3 group. Astrocyte hyperplasia represented by gray value in the IN-1 group was less than the control group. Gray value of GFAP-positive products in the IN-1/IN-3 group was higher than other two groups （P 〈 0.05）. Biotin dextran amine tracing demonstrated no corticospinal tract fiber outgrowth following spinal cord injury; the fibers were incapable of passing through the glial scar in the control group. Several fibers were distributed in the proximal scar tissue region in the IN-1 group, and the regenerated fibers were disarranged. Many nerve fibers were distributed throughout the scar tissue, and even several biotin dextran amine-positive fibers were observed at the distal end of the injured segment. Post-operative Basso, Beattie, Bresnahan scores were greater than pre-operative ones, while Basso, Beattie, Bresnahan scores in the IN-1/NT-3 group were significantly greater than the other two groups at days 14, 21, and 28 post-surgery （P 〈 0.05）. CONCLUSION： IN-1, in combination with NT-3, promoted axonal regeneration following spinal cord injury, inhibited the colloidal effect, and enhanced the correlation between proximal and distal processes to recover motor function. The recovery effect of IN-1/NT-3 on motor function was superior that of to IN-1 alone.
文摘The role of neurotrophins in neuronal plasticity has recently become a strong focus in neuroregeneration research field to elucidate the biological mechanisms by which these molecules modulate synapses,modify the response to injury,and alter the adaptation response.Intriguingly,the prior studies highlight the role of p75 neurotrophin receptor(p75^(NTR))in various injuries and diseases such as central nervous system injuries,Alzheimer's disease and amyotrophic lateral sclerosis.More comprehensive elucidation of the mechanisms,and therapies targeting these molecular signaling networks may allow for neuronal tissue regeneration following an injury.Due to a diverse role of the p75^(NTR)in biology,the body of evidence comprising its biological role is diffusely spread out over numerous fields.This review condenses the main evidence of p75^(NTR)for clinical applications and presents new findings from published literature how data mining approach combined with bioinformatic analyses can be utilized to gain new hypotheses in a molecular and network level.
基金supported by Scientific Research Fund of Xinxiang Medical University,No.2013ZD120Science and Technology Innovation Talents in Universities in Ministry of Education of Henan Province in 2010,No.2010HASTIT036
文摘Bone marrow mesenchymal stem cell transplantation has been shown to be therapeutic in the repair of spinal cord injury. However, the low survival rate of transplanted bone marrow mesen- chymal stem cells in vivo remains a problem. Neurotrophin-3 promotes motor neuron survival and it is hypothesized that its transfection can enhance the therapeutic effect. We show that in vitro transfection of neurotrophin-3 gene increases the number of bone marrow mesenchymal stem cells in the region of spinal cord injury. These results indicate that neurotrophin-3 can promote the survival of bone marrow mesenchymal stem cells transplanted into the region of spinal cord injury and potentially enhance the therapeutic effect in the repair of spinal cord injury.
基金supported by Programa de Apoyo a Proyectos de Investigación e Innovación Tecnológica Grants No.216515 and IN 211718。
文摘This manuscript reviews the function and fundamental characteristics of the neurotrophins and their receptors to introduce the reader to the differential effects exhibited by the neurotrophins;brain-derived neurotrophic factor and neurotrophin 4/5 when acted together after sequential presentation.The neurotrophin 4/5 exhibits an inhibitory action on the modulatory effect of brain-derived neurotrophic factor in corticostriatal synapses when they are administered sequentially(brain-derived neurotrophic factor to neurotrophin 4/5).This inhibitory effect has not been previously documented and is relevant for these neurotrophins as both of them stimulate the TrkB receptor.The additive effect of these neurotrophins is also discussed and occurs when neurotrophin 4/5 exposure is followed by brain-derived neurotrophic factor in a mouse model of striatal degeneration.Occlusive and additive effects of both neurotrophins are accompanied by changes in the expression of the TrkB receptor isoforms,specifically TrkB-T1 and TrkB-FL,as well as differences in phosphorylation levels of the TrkB receptor.The results of the experiments described raise several questions to inquire about the role that TrkB-T1 receptor plays in striatal physiology,as well as the functional relevance of the interaction of brain-derived neurotrophic factor and neurotrophin 4/5 in the brain and more specifically at the striatal circuits in normal as well as pathological conditions.
基金financially supported by the grants for Science and Technology Innovation Talents in Universities in Ministry of Education of Henan Province in 2010,No.2010HASTIT036
文摘Schwann ceils and neurotrophin-3 play an important role in neural regeneration, but the secretion of neurotrophin-3 from Schwann cells is limited, and exogenous neurotrophin-3 is inactived easily in vivo. In this study, we have transfected neurotrophin-3 into Schwann cells cultured in vitro using nanoparticle liposomes. Results showed that neurotrophin-3 was successfully transfected into Schwann cells, where it was expressed effectively and steadily. A composite of Schwann cells transfected with neurotrophin-3 and poly（lactic-co-glycolic acid） biodegradable conduits was transplanted into rats to repair 10-mm sciatic nerve defects. Transplantation of the composite scaffold could restore the myoelectricity and wave amplitude of the sciatic nerve by electrophysiological examination, promote nerve axonal and myelin regeneration, and delay apoptosis of spinal motor neurons. Experimental findings indicate that neurotrophin-3 transfected Schwann cells combined with bridge grafting can promote neural regeneration and functional recovery after nerve injury.
基金the National Natural Science Foundation of China, No. 30672136
文摘BACKGROUND： Studies have demonstrated that cauda equina compression results in apoptosis of motor neurons in the spinal cord. The combination of p75 neurotrophin receptor （p75NTR） and precursor of nerve growth factor （pro-NGF） expression initiates the apoptotic pathway and induces neuronal apoptosis. However, few reports have focused on the p75-mediated mechanism of neuronal apoptosis following cauda equine compression injury OBJECTIVE： To determine apoptosis of spinal cord neurons and activation of the pro-NGF-p75NTR-JNK（c-Jun N-terminal kinase） signal pathway in rats following cauda equina compression, and to verify experimental outcomes. DESIGN, TIME AND SETTING： A randomized, controlled, in vivo experiment was performed at the Medical Experimental Center of Xi＇an Jiaotong University between April and November in 2008. MATERIALS： Streptavidin-perosidase kit was purchased from Wuhan Boster, China; in situ end labeling detection kit was provided by Promega, USA; type AEG-220G electron microscope was purchased from Hitachi, Japan. METHODS： A total of 48 healthy, adult, female, Sprague Dawley rats were randomly assigned to three groups： normal （n = 6）, sham-surgery （n = 6）, and compression （n = 36）. The compression group was randomly assigned to six subsets at 1,3, 5, 7, 14, and 28 days, respectively, with 6 rats in each subset. A cylindrical silica gel stick was implanted into the rats to compress 75% of the vertebral canal in the compression group; in the sham-surgery group, only vertebral resection was performed; and no procedures were performed in the normal group. MAIN OUTCOME MEASURES： At 1,3, 5, 7, 14, and 28 days following compression, L2-3 spinal cord segments were processed for immunohistochemistry, in situ cell apoptosis detection, and transmission electron microscopy observation. Nissl staining was used to observe neuronal survival in the L2 spinal cord segment. Immunohistochemistry was applied to detect expressions of pro-NGF, p75NTR, and JNK in the L2 segment. TUNEL fluorometric method was used to observe apoptosis of neurons in the L2 segment. RESULTS： In the normal and sham-surgery groups, little neuronal apoptosis was observed in the L2-3 spinal cord segment. At 3 days after compression injury, pro-NGF, p75NTR and JNK expression was observed in the spinal cord. Expression levels reached a peak at 7 days, and then gradually decreased. In the compression and sham-surgery groups, neurons primarily expressed pro-NGF and p75NTR. The number of JNK-positive neurons in the compression group was dramatically increased compared with the sham-surgery group （P〈 0.05）. A few neurons were apoptotic in the spinal cord 1 day after compression injury. The number of apoptotic neurons gradually increased and reached a peak at 7 days, and subsequently decreased. Apoptosis was still detectable at 28 days. There was a positive correlation between p75NTR expression and neuronal apoptosis （r= 0.75, P〈 0.05）. CONCLUSION： Following cauda equina compression injury, apoptosis of spinal cord neurons was observed. The compression-induced neuronal apoptosis was associated with p75NTR expression in the L2-3 spinal cord segment.
基金the Science and Technology Research and Development Program of Shaanxi Province, No. 2007K15-01
文摘This study demonstrated that brain areas surrounding the site of hematoma following intracerebral hemorrhage are characterized by significantly increased apoptosis and expression of neurotrophin receptor p75 and sortilin. However, as detected by terminal deoxynucleotidyl transferase dUTP nick end labeling and immunohistochemical staining, there was no significant change in nerve growth factor precursor expression levels. The appearance of neurotrophin receptor p75 expressing cells was positively correlated with cells that were detected by terminal deoxynucleotidyl transferase dUTP nick end labeling. These findings confirm that the nerve growth factor precursor-neurotrophin receptor p75-sortilin heterotrimeric complex-mediated apoptosis pathway may play an important role in cellular apoptosis following intracerebral hemorrhage.
基金a Grant from Department of Health of Hunan Province of China,No.B2005-076
文摘BACKGROUND： Nogo-neutralizing antibody IN-1 accelerates axon growth and enhances recovery of spinal cord function by inhibiting growth inhibitory factors. Neurotrophin-3 （NT-3）contributes to regeneration of nerve fibers in the spinal cord and motor function recovery. The combination of Nogo-neutralizing antibody IN-1 and NT-3 is hypothesized to produce better outcomes and facilitate axonal regeneration by affecting c-Fos and c-Jun protein expression. OBJECTIVE： To investigate the combined effects of Nogo-neutralizing antibody IN-1 and NT-3 on c-Fos and c-Jun protein levels in the injured spinal cord. DESIGN, TIME AND SETTING： A randomized, controlled study was performed at the Laboratory of Neuroanatomy, Xiangya Medical College, Central South University and the Central Laboratory of Third Xiangya Hospital of China from June 2005 to December 2007. MATERIALS： NT-3 （Peprotech, USA） and Nogo-neutralizing antibody IN-1 （Santa Cruz Biotechnology, USA） were used in this study. METHODS： Hemisectioned spinal cord injury models were established by cutting the posterior 2/3 of rat spinal cord, which is equivalent to the T8 level in the human spine. A total of 120 rats were equally and randomly assigned to three groups： model （0.2 μL saline）, IN-1 （0.2 μL IN-1）, and IN-1/NT-3 （0.2 μL IN-1 ＋ 0.2 μL NT-3）. The compounds were separately infused into transection sites on the side of head. MAIN OUTCOME MEASURES： Western blot analysis was employed to measure c-Fos and c-Jun protein expression in the injured spinal cord at 15, 30 minutes, 1,2, 4, 6, 8, and 12 hours following surgery. RESULTS： Following spinal cord injury, c-Fos and c-Jun protein expression were increased and peaked at 4 6 hours. Following injection of IN-1 or the combination of IN-1 and NT-3, c-Fos protein expression was significantly reduced in the injured spinal cord （P 〈 0.05 or P 〈 0.01） （with the exception of the 15 minute time point）. However, c-Jun protein expression was significantly increased （P〈 0.05 or P〈 0.01） （with the exception of the 15 and 30 minute time points）. Combined application of IN-1 and NT-3 resulted in significantly altered protein expression compared to IN-1 alone. CONCLUSION： IN-1 increases c-Jun protein levels and protects the injured spinal cord by inhibiting c-Fos protein levels. Moreover, the effects of IN-1 combined with NT-3 are more significant than with IN-1 alone.
基金supported by grants from the Shanghai Municipal Commission of Health and Family PlanningNo.20114351+3 种基金the Traditional Chinese Medicine Science Funding of Zhejiang Province of ChinaNo.2010ZB091the Natural Science Foundation of Zhejiang Province of ChinaNo.Y2090864
文摘In the present study, we investigated the role of endogenous neurotrophin-3 in nerve terminal sprouting 2 months after spinal cord dorsal root rhizotomy. The left L1-5 and L7-S2 dorsal root ganglia in adult cats were exposed and removed, preserving the L6 dorsal root ganglia. Neurotrophin-3 was mainly expressed in large neurons in the dorsal root ganglia and in some neurons in spinal lamina II. Two months after rhizotomy, the number of neurotrophin-3-positive neurons in the spared dorsal root ganglia and the density of neurite sprouts emerging from these ganglia were increased. Intraperitoneal injection of an antibody against neurotrophin-3 decreased the density of neurite sprouts. These findings suggest that endogenous neurotrophin-3 is involved in spinal cord plasticity and regeneration, and that it promotes axonal sprouting from the dorsal root ganglia after spinal cord dorsal root rhizotomy.
文摘Neurotrophic factors are able to promote neuronalsurvival and prevent neuronal death induced by variousinjuries and have potential uses in the treatment ofneuronal degenerative diseases and neuropathy. Due tothe existence of brain blood barrier, neurotrophic factorscan not be ased in CNS diseases directly. Gene therapy isa good candidate to overcome this problem.
基金supported by the National Natural Science Foundation of China, No. 30973262
文摘Neurotrophin-3 （NT-3） can promote the repair of central nervous system and retinal damage. In previous reports, NT-3 has been expressed by viral vectors. However, plasmid vectors have a safer profile compared with viral vectors in clinical studies. This study recombined amplified human retinal NT-3 with a eukaryotic expression plasmid containing green fluorescent protein （GFP） to construct an NT-3 expression plasmid, pEGFP-N1-NT-3. The transfection efficiency 48 hours after pEGFP-N1-NT-3 transfection to 293T cells was 50.06 ＋ 2.78%. Abundant NTo3-GFP was expressed in 293T cells as observed by fluorescence microscopy, suggesting the construct pEGFP-N1-NT-3 effectively expressed and secreted NT-3-GFP. Secretory vesicles containing NT-3-GFP were observed in a constant location in cells by laser scan confocal microscopy, indicating the expression and secretion processes of NT-3 in eukaryotic cells were in accordance with the physical synthesis processes of secreted proteins. Western blot assay showed that pro-NTo3-GFP had a molecular weight of 56 kDa, further confirming NT-3-GFP expression. At 48 hours after transfection, the concentration of NT-3 in culture medium was 22.3 ng/mL, suggesting NT-3 produced by pEGFP-N1-NT-3 was efficiently secreted. This study constructed a human retinal-derived NT-3 eukaryotic expression plasmid that efficiently expressed and secreted NT-3.
