Lianmei Qiwu Decoction relieves diabetic cardiac autonomic neuropathy by regulating AMPK/TrkA/TRPM7 signaling pathway / 中国中药杂志

This study investigated the effect of Lianmei Qiwu Decoction(LMQWD) on the improvement of cardiac autonomic nerve remodeling in the diabetic rat model induced by the high-fat diet and explored the underlying mechanism of LMQWD through the AMP-activated protein kinase(AMPK)/tropomyosin receptor kinase A(TrkA)/transient receptor potential melastatin 7(TRPM7) signaling pathway. The diabetic rats were randomly divided into a model group, an LMQWD group, an AMPK agonist group, an unloaded TRPM7 adenovirus group(TRPM7-N), an overexpressed TRPM7 adenovirus group(TRPM7), an LMQWD + unloaded TRPM7 adenovirus group(LMQWD+TRPM7-N), an LMQWD + overexpressed TRPM7 adenovirus group(LMQWD+TRPM7), and a TRPM7 channel inhibitor group(TRPM7 inhibitor). After four weeks of treatment, programmed electrical stimulation(PES) was employed to detect the arrhythmia susceptibility of rats. The myocardial cell structure and myocardial tissue fibrosis of myocardial and ganglion samples in diabetic rats were observed by hematoxylin-eosin(HE) staining and Masson staining. The immunohistochemistry, immunofluorescence, real-time quantitative polymerase chain reaction(RT-PCR), and Western blot were adopted to detect the distribution and expression of TRPM7, tyrosine hydroxylase(TH), choline acetyltransferase(ChAT), growth associated protein-43(GAP-43), nerve growth factor(NGF), p-AMPK/AMPK, and other genes and related neural markers. The results showed that LMQWD could significantly reduce the arrhythmia susceptibility and the degree of fibrosis in myocardial tissues, decrease the levels of TH, ChAT, and GAP-43 in the myocardium and ganglion, increase NGF, inhibit the expression of TRPM7, and up-regulate p-AMPK/AMPK and p-TrkA/TrkA levels. This study indicated that LMQWD could attenuate cardiac autonomic nerve remodeling in the diabetic state, and its mechanism was associated with the activation of AMPK, further phosphorylation of TrkA, and inhibition of TRPM7 expression.

Gastrodin injection alleviates lung injury caused by focal cerebral ischemia in rats through NGF/TrkA pathway-mediated activation of the anti-inflammatory pathway / 南方医科大学学报

OBJECTIVE@#To investigate the therapeutic mechanism of gastrodin injection for alleviating lung injury caused by focal cerebral ischemia in rats and the role of the NGF-TrkA pathway in mediating this effect.@*METHODS@#Forty SD rats were equally randomized into normal group, sham-operated group, model group and gastrodin group, and in the latter two groups, rat models of focal cerebral ischemia were established by embolization of the right middle cerebral artery. After successful modeling, the rats were treated with intraperitoneal injection of gastrodin injection at the daily dose of 10 mg/kg for 14 days. After the treatment, the wet/dry weight ratio of the lung tissue was determined, the pathological changes in the lung tissue were observed using HE staining, and the levels of IL-10 and TNF-α in the arterial blood were detected with ELISA. The expressions of NF-κB p65 and TNF-α in the lung tissue were detected with Western blotting, and the expressions of NGF and TrkA were detected using immunohistochemical staining and Western blotting.@*RESULTS@#Compared with the normal control and sham-operated groups, the rats in the model group showed obvious inflammatory lung injury, significantly increased wet/ dry weight ratio of the lungs (P < 0.01), increased TNF-α level in arterial blood (P < 0.01), and significantly up-regulated protein expressions of NF-κB p65 (P < 0.01), TNF-α (P < 0.01), NGF (P < 0.05) and TrkA(P < 0.05) in the lung tissue. Treatment with gastrodin injection obviously alleviated lung inflammation, decreased the wet/dry weight ratio of the lungs (P < 0.05), and significantly lowered TNF-α level (P < 0.01) and increased IL-10 level in the arterial blood in the rat models (P < 0.01); gastrodin injection also significantly decreased the protein expressions of NF-κB p65 and TNF-α (P < 0.05) and up-regulated the expressions of NGF and TrkA in the lung tissue of the rats (P < 0.05).@*CONCLUSION@#The NGF/TrkA pathway may participate in cerebral ischemia-induced inflammatory lung injury, which can be obviously alleviated by gastrodin through the activation of the anti-inflammatory pathway mediated by the NGF/TrkA pathway.

Expressão de neurotrofinas e de seus receptores no osteossarcoma primário / Expression of neurotrophins and their receptors in primary osteosarcoma

RESUMO Objetivo: determinar a expressão de neurotrofinas e seus receptores tirosina quinases em pacientes com osteossarcoma (OS) e sua correlação com desfechos clínicos. Métodos: biópsias de tumores primários de pacientes com OS tratados em uma única instituição, consecutivamente, entre 2002 e 2015, foram analisados através de imuno-histoquímica para expressão de receptores de tirosina quinase A e B (TrKA e TrKB), fator de crescimento neural (NGF) e fator neurotrófico derivado do cérebro (BDNF). De forma independente, dois patologistas classificaram os marcadores de imuno-histoquímica como negativos (negativos e focais fracos) ou positivos (moderado focal/difuso ou forte focal/difuso). Resultados: foram analisados dados de 19 pacientes (10 do sexo feminino e 9 do masculino) com mediana de idade de 12 anos (5 a 17,3 anos). Dos tumores, 83,3% estavam localizados em membros inferiores e 63,2% dos pacientes eram metastáticos ao diagnóstico. A sobrevida global em cinco anos foi de 55,3%. BDNF foi positivo em 16 pacientes (84%) e NGF em 14 pacientes (73%). TrKA e TrKB apresentaram coloração positiva em quatro (21,1%) e oito (42,1%) pacientes, respectivamente. A análise de sobrevida não demonstrou diferença significativa entre receptores TrK e neurotrofinas. Conclusão: amostras de OS primário expressam neurotrofinas e receptores TrK através de imuno-histoquímica. Estudos futuros podem auxiliar na identificação do papel das mesmas na patogênese do OS e determinar se há possível correlação prognóstica.

ABSTRACT Objective: to determine the expression of neurotrophins and their tyrosine-kinase receptors in patients with osteosarcoma (OS) and their correlation with clinical outcomes. Methods: we applied immunohistochemistry to biopsy specimens of patients consecutively treated for primary OS at a single institution between 2002 and 2015, analyzing them for expression receptors of tyrosine kinase A and B (TrKA and TrKB), neural growth factor (NGF) and brain derived neurotrophic factor (BDNF). Independently, two pathologists classified the immunohistochemical markers as negative (negative or weak focal) or positive (moderate focal/diffuse or strong focal/diffuse). Results: we analyzed data from 19 patients (10 females and 9 males), with median age of 12 years (5 to 17.3). Tumors' location were 83.3% in the lower limbs, and 63.2% of patients had metastases at diagnosis. Five-year overall survival was 55.3%. BDNF was positive in 16 patients (84%) and NGF in 14 (73%). TrKA and TrKB presented positive staining in four (21,1%) and eight (42,1%) patients, respectively. Survival analysis showed no significant difference between TrK receptors and neurotrophins. Conclusion: primary OS samples express neurotrophins and TrK receptors by immunohistochemistry. Future studies should explore their role in OS pathogenesis and determine their prognostic significance in larger cohorts.

Mouse Nerve Growth Factor Facilitates the Growth of Interspinal Schwannoma Cells by Activating NGF Receptors

OBJECTIVE: Nerve growth factor (NGF) is a member of the neurotrophic factor family and plays a vital role in the physiological processes of organisms, especially in the nervous system. Many recent studies have reported that NGF is also involved in the regulation of tumourigenesis by either promoting or suppressing tumor growth, which depends on the location and type of tumor. However, little is known regarding the effect of NGF on interspinal schwannoma (IS). In the present study, we aimed to explored whether mouse nerve growth factor (mNGF), which is widely used in the clinic, can influence the growth of interspinal schwannoma cells (ISCs) isolated from IS in vitro.METHODS: ISCs were isolated, cultured and identified by S-100 with immunofluorescence analysis. S-100-positive cells were divided into five groups, and separately cultured with various concentrations of mNGF (0 [phosphate buffered saline, PBS], 40, 80, 160, and 320 ng/mL) for 24 hours. Western blot and quantantive real time polymerase chain reaction (PCR) were applied to detect tyrosine kinase A (TrkA) receptor and p75 neurotrophin receptor (p75(NTR)) in each group. Crystal violet staining was selected to assess the effect of mNGF (160 ng/mL) on ISCs growth.RESULTS: ISCs growth was enhanced by mNGF in a dose-dependent manner. The result of crystal violet staining revealed that it was significantly strengthened the cells growth kinetics when cultured with 160 ng/mL mNGF compared to PBS group. Western blot and quantantive real time PCR discovered that TrkA receptor and mRNA expression were both up-regualated under the condition of mNGF, expecially in 160 ng/mL, while the exoression of p75(NTR) demonstrated no difference among groups.CONCLUSION: From these data, we conclude that exogenous mNGF can facilitate ISC growth by activating both TrkA receptor and p75(NTR). In addition, patients who are suffering from IS should not be administered mNGF in the clinic.

Mouse Nerve Growth Factor Facilitates the Growth of Interspinal Schwannoma Cells by Activating NGF Receptors

OBJECTIVE: Nerve growth factor (NGF) is a member of the neurotrophic factor family and plays a vital role in the physiological processes of organisms, especially in the nervous system. Many recent studies have reported that NGF is also involved in the regulation of tumourigenesis by either promoting or suppressing tumor growth, which depends on the location and type of tumor. However, little is known regarding the effect of NGF on interspinal schwannoma (IS). In the present study, we aimed to explored whether mouse nerve growth factor (mNGF), which is widely used in the clinic, can influence the growth of interspinal schwannoma cells (ISCs) isolated from IS in vitro. METHODS: ISCs were isolated, cultured and identified by S-100 with immunofluorescence analysis. S-100-positive cells were divided into five groups, and separately cultured with various concentrations of mNGF (0 [phosphate buffered saline, PBS], 40, 80, 160, and 320 ng/mL) for 24 hours. Western blot and quantantive real time polymerase chain reaction (PCR) were applied to detect tyrosine kinase A (TrkA) receptor and p75 neurotrophin receptor (p75(NTR)) in each group. Crystal violet staining was selected to assess the effect of mNGF (160 ng/mL) on ISCs growth. RESULTS: ISCs growth was enhanced by mNGF in a dose-dependent manner. The result of crystal violet staining revealed that it was significantly strengthened the cells growth kinetics when cultured with 160 ng/mL mNGF compared to PBS group. Western blot and quantantive real time PCR discovered that TrkA receptor and mRNA expression were both up-regualated under the condition of mNGF, expecially in 160 ng/mL, while the exoression of p75(NTR) demonstrated no difference among groups. CONCLUSION: From these data, we conclude that exogenous mNGF can facilitate ISC growth by activating both TrkA receptor and p75(NTR). In addition, patients who are suffering from IS should not be administered mNGF in the clinic.

Investigating Trk Protein Expression between Oropharyngeal and Non-oropharyngeal Squamous Cell Carcinoma: Clinical Implications and Possible Roles of Human Papillomavirus Infection / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: The relationship between head and neck squamous cell carcinoma (HNSCC) and subtypes of tropomyosin-related kinase (Trk) has not been studied in-depth. In this study, we evaluated the expression patterns of TrkA, TrkB, and panTrk and their clinicopathological significance as well as association with p16 expression and human papilloma virus (HPV) status. MATERIALS AND METHODS: Total of 396 radically resected oropharyngeal (n=121) and non-oropharyngeal (n=275) HNSCCs were included. Immunohistochemistry for TrkA, TrkB, and panTrk was performed. In addition, p16 immunohistochemistry was performed to assess the HPV status. Using HPV-negative HNSCC cell lines, FaDu and CAL27, HPV type 16 E6/E7 gene was transfected, and then changes of TrkA and TrkB expression were analyzed. RESULTS: In the clinical samples of HNSCC, high expression of TrkA and panTrk were more associated with oropharyngeal and p16 positive squamous cell carcinoma (SCC). In patients with completely resected (R0-resected) oropharyngeal SCC, high TrkA expression was related to superior overall survival and recurrence-free survival (RFS). In patients with R0-resected oral cavity SCC, high panTrk was related to poor RFS. In HPV type E6/E7 gene-transfected FaDu and CAL27 cell lines, increase of TrkA expression was observed. CONCLUSION: It seems that expression pattern of panTrk and TrkA differed according to anatomical sites of HNSCC and was closely related to p16 expression and patient prognosis. Trk expression should be considered in the context of anatomical site, p16 expression or HPV status and Trk subtypes.

Whole-tissue 3D imaging reveals intra-adipose sympathetic plasticity regulated by NGF-TrkA signal in cold-induced beiging

Sympathetic arborizations act as the essential efferent signals in regulating the metabolism of peripheral organs including white adipose tissues (WAT). However, whether these local neural structures would be of plastic nature, and how such plasticity might participate in specific metabolic events of WAT, remains largely uncharacterized. In this study, we exploit the new volume fluorescence-imaging technique to observe the significant, and also reversible, plasticity of intra-adipose sympathetic arborizations in mouse inguinal WAT in response to cold challenge. We demonstrate that this sympathetic plasticity depends on the cold-elicited signal of nerve growth factor (NGF) and TrkA receptor. Blockage of NGF or TrkA signaling suppresses intra-adipose sympathetic plasticity, and moreover, the cold-induced beiging process of WAT. Furthermore, we show that NGF expression in WAT depends on the catecholamine signal in cold challenge. We therefore reveal the key physiological relevance, together with the regulatory mechanism, of intra-adipose sympathetic plasticity in the WAT metabolism.

Effect of nervous growth factor on the proliferation of the limbal stem cells in vitro / 局解手术学杂志

Objective To investgate the effect of nervous growth factor(NGF) on the proliferation of the limbal stem cells(LSCs) in vitro,and the relationship bewteen expression of its receptors and cell proliferation.Methods After primary cultured,LSCs were divided into the control group and the NGF group.Selected cells cultured of 1 d,3 d and 5 d in the two groups and examined the expression of p63,TrkA,p75 with immunohistochemistry.Results The average gray scale values of expression of p63,TrkA and p75 at 1 d,3 d and 5 d in NGF group were significant decreased compared with the corresponding data in the control group(P<0.05).Pearson's correlations analysis showed that the average gray scale values of expression of TrkA and p63 were of statistically significant differences(P<0.05).Conclusion These results highlight that NGF could maintain the stem cell properties of LSCs.LSCs could exepress the NGF receptors of TrkA and p75,and the expression of TrkA showed a correlation with LSCs proliferation.

The role of TrkA/TrkB in radiation-induced hippocampal neurogenesis impairment / 中华放射医学与防护杂志

Objective To investigate the roles of TrkA and TrkB in radiation-induced hippocampal neurogenesis impairment.Methods Fifty-six rats were randomized into radiation group and sham control group.Radiation group received whole brain irradiation at a single dose of 10 Gy.The hippocampus were separated from rats in day 1,day 3,day 14 and 1 month after irradiation.Western blot and RT-PCR were applied to detect the protein levels and mRNA levels.Golgi staining was used to observe the dendritic spine of hippocampus.Immunofluorescence was performed to detect neural precursor's proliferation.Results Compared with control group,the numbers of dendritic spine significantly decreased after irradiation and its shape change obviously.Immunofluorescence showed a significant decrease in neural precursor's proliferation comparing with control group (t =6.49,P ＜ 0.05).Protein level of TrkA expression increased (t =2.64,3.06,4.80,2.64,P ＜ 0.05),while the levels of TrkB protein expression decreased significantly (t =4.59,3.06,2.81,2.57,P ＜ 0.05).The mRNA level of TrkA expressions increased (t =4.57,3.06,5.39,5.86,P ＜ 0.05),while the mRNA level of TrkB decreased (t =14.87,11.69,4.98,P ＜ 0.05).Conclusions As a signaling pathways downstream of NGF and BDNF,TrkA and TrkB may play an important role in radiation-induced neurogenesis impairment.

Memantine improves cognitive deficits by activiating NGF/TrkA signaling in APP/PS1 transgenic mice / 中国药理学通报

Aims To study the role of NGF/Trk A sig-naling pathway in Memantine ( MEM) improving APP/PS1 transgenic mice cognitive deficits and to explore its possible mechanisms. Methods Cognitive perform-ance was assessed by Morris water maze( MWM) , pas-sive avoidance test( PAT) and locomotivity test. Aβ1-42 protein levels were determined by immunohistochemis-try. The activities of AChE and ChAT were also exam-ined by ELISA and colorimetry. Western blot was used to detect the expression levels of NGF and its receptor TrkA and the downstream ERK pathway. Results MEM treatment significantly ameliorated the cognitive deficits, dramatically reduced the Aβ1-42 overexpres-sion. MEM increased the activity of choline acetyl-transferase( ChAT) , while decreased that of acetylcho-line esterase( AChE) . Moreover, MEM activiated NGF signaling by increasing the phosphorylation of TrkA fol-lowing the increased phosphorylation of c-Raf, ERK1/2 and downstream effector CREB after MEM treatment. Conclusion MEM treatment may activate the NGF/TrkA signaling in APP/PS1 mice to reduce amyloidosis and cognitive deficits.

Effect of exercise preconditioning on nerve growth factor and learning-and-memory abilities in rats suffered from focal cerebral ischemia / 中华行为医学与脑科学杂志

Objective To investigate the effect of exercise preconditioning on the expression of nerve growth factor(NGF) and its receptor TrkA as well as learning-and-memory abilities in rats suffered from focal cerebral ischemia.Methods Thirty-six male SD rats were randomly divided into sham operation group (Sham-MCAO,n=12),focal cerebral ischemia-reperfusion group (MCAO,n=12) and exercise preconditioning + cerebral ischemia-reperfusion group (EX+MCAO,n=12).Rats in EX+MCAO group were placed in the treadmill device and accepted 4 weeks exercise training.Then method of middle cerebral artery occlusion was applied to prepare transient focal cerebral ischemia reperfusion model.Garcia's method was used to assess the neural function in rats.Western blotting was applied to test the expression of NGF and TrkA protein in the successfully established experimental MCAO rats.Morris water maze experiment was uti lized to test the learning-and-memory abilities of the rats.Results (1) Compared with Sham-MCAO group,the expression of NGF in rats' brain tissue was lower in MCAO group (cerebral ischemia 1h reperfusion 24h) (P＜0.05).The expression of NGF of EX+MCAO group was higher than that of MCAO group,but still lower than that of Sham-MCAO group (P＜0.05).(2)The expression of TrkA in rats' brain tissue was higher in MCAO group compared with Sham-MCAO group (P＜0.05).Compared with MCAO group,the expression of TrkA was even higher in EX+MCAO group (P＜0.05).(3)On the fifth day in the Morris water maze test,the latency of MCAO group was significantly longer than that of Sham-MCAO group((9.36± 1.18)s vs (4.86± 1.52) s,P＜0.05).However,compared with MCAO group,the latency in EX+MCAO group ((6.02± 1.04) s) was shorter,but still longer than Sham-MCAO group (P＜0.05).There was no significant difference among the three groups in the average swimming speed (P＞0.05).Conclusion Exercise preconditioning can up-regulate the expressions of NGF and TrkA protein,which can also improve the learning-and-memory abilities in rats suffered from focal cerebral ischemia reperfusion injury.

Age-related degeneration of auditory function and the expression of NGFR TrkA in the cochlea of senescence-accelerated mouse / 实用医学杂志

Objective To explore hearing loss , the expression of age-related changes of nerve growth factor receptor TrkA (NGFR TrkA ) in the cochlea of the senescence-accelerated mouse. Methods The senescence accelerated mouse/prone 8(SAMP8) at 3, 5, 7 months were chosen as analyzing subjects. The auditory thresholds was monitored by auditory brainstem respons (ABR). The expression of NGFR TrkA protein was analyzed by the optical density of immunohistochemical staining. Results The SAMP8 developed a progressive auditory threshold which showed an age-related significant increase (P < 0.05). There were NGFR TrkA protein expressed in the cochlea of the SAMP8 throughout the development, which developed an age-related significant descend (P<0.05). Conclusion The expression level of NGFR TrkA protein decreases when the SAMP 8 develops a progressive hearing loss which indicates that NGFR TrkA protein probably has relationship with maintaining functional status of the cochlea.

In vitro and in vivo study of effects of fermented soybean product (chungkookjang) on NGF secretion ability and NGF receptor signaling pathway / 한국실험동물학회지

In order to investigate the effects of a fermented soybean product (Chungkookjang, CKJ) on nerve growth factor (NGF) metabolism, NGF secretion ability and its related signaling pathway were analyzed in B35 neuronal cells and the Tg2576 mouse model of Alzheimer's disease (AD). In B35 cells, the concentration of NGF significantly increased upon treatment with Taegwang (TG)-CKJ and Shinhwa (SH)-CKJ extracts compared with vehicle. Further, a significant increase in PC12 cell length as well as the phsophorylation levels of TrkA and Akt, which are members of a high affinity NGF receptor signaling pathway, were observed after treatment with TG-CKJ and SH-CKJ conditional medium (CM). On the other hand, there was no difference in activation of the NGF receptor p75NTR signaling pathway between vehicle and all CKJ treated groups. In Tg2576 mice showing early stage of AD, the concentrations of NGF in the serum and brain were reduced compared with those in Non-Tg mice. Treatment of Tg2576 mice with SH-CKJ, which contains high concentrations of total flavonoids and phenolic compounds, for 8 weeks dramatically recovered the NGF level to that of Non-Tg mice. Furthermore, the low phosphorylation levels of TrkA and Erk in the NGF receptor TrkA signaling pathway were rapidly recovered to those of Non-Tg mice after SH-CKJ treatment in vehicle treated Tg2576 mice, whereas the phosphorylation level of Akt was maintained at a constant level. These results suggest that CKJ may stimulate NGF secretion ability as well as the NGF receptor TrkA signaling pathway in PC12 cells and Tg2576 mice.

Expression of nerve growth factor and nerve growth factor receptor in human pancreatic cancer and its clinical significance / 第二军医大学学报

Objective: To explore the expression of nerve growth factor (NGF), its receptor P75NGFR and TrkA in the human pancreatic cancer tissues, and to study the relationship between the expression and clinical-pathological indices. Methods: The expression and morphological distribution of NGF, P75NGFR and TrkA were investgated in 65 pancreatic cancer tissues and 18 normal pancreas and chronic pancreatitis tissues by means of immunohistochemistry; the relationship between the expression and clinical-pathological indices was also investigated. Results: The expression of NGF and TrkA in human pancreatic cancer tissues was higher than that in the normal pancreas and chronic pancreatitis. Expression of P75NGFR had no significant change in the two groups. The expression of NGF was positively correlated with tumor size and was also associated with lymphatic invasion. The expression of P75NGFR and TrkA was closely correlated with lymphatic invasion. We also found that the expression of NGF was correlated with histological differentiation, tumor stage, tumor size and lymphatic invasion; the closest relationship was found between the expression of NGF and tumor size. The expression of P75NGFR was correlated with lymphatic invasion, the expression of TrkA was Correlated with both lymphatic invasion and tumor TNM stage. Patient's prognosis after surgery was mainly correlated with lymphatic invasion and the positive expression of TrkA. Conclusion: NGF, P75NGFR and TrkA participate in the progress of pancreatic cancer. TrkA is closely related to pancreatic cancer and can serve as an important target for gene therapy of pancreatic cancer in the future.

Effect of NGF on Cultured Human Retinal Capillary Endothelial Cells(HRCEC) / 中山大学学报(医学科学版)

[Objective] To observe NGF on cultured human retinal vascular endothelial cells (HRCEC) proliferation. [Methods] The MTT assay was used to analyze the impact of culture HRCEC on different factors (NGF concentration groups, NGF + K252a concentration groups, bFGF group, bFGF + K252a groups, the normal culture medium groups) in normal and hypoxic condition. [Results] With the increase of NGF concentration (20,50,100 ng/mL), HRCEC significantly increased (normal condition: 0.254±0.033,0.696±0.029, 1.136±0.051; hypoxic condition: 0.422±0.036, 0.798±0.044, 1.376±0.052, P< 0.05). Compared NGF + K252a group with the same concentration of NGF (100 ng/ml) group, HRCEC reduced (P<0.05), with increasing the concentration of K252a (50,100,200 nmol/L), the trend of HRCEC decreasing is become more significant (normal condition:0.864±0.067, 0.496±0.025, 0.202±0.078; hypoxic condition:K252a 1.042±0.047,0.700±0.065, 0.401±0.078, P<0.05). [Conclusion] NGF can promote the proliferation of HRCEC, the effect could be specifically blocked by TrkA inhibitor K252a.

Neuroprotection signaling pathway of nerve growth factor and brain-derived neurotrophic factor against staurosporine induced apoptosis in hippocampal H19-7 cells

Neurotrophins protect neurons against excitotoxicity; however the signaling mechanisms for this protection remain to be fully elucidated. Here we report that activation of the phosphatidyl inositol 3 kinase (PI3K)/Akt pathway is critical for protection of hippocampal cells from staurosporine (STS) induced apoptosis, characterized by nuclear condensation and activation of the caspase cascade. Both nerve growth factor (NGF) and brain-derived growth factor (BDNF) prevent STS-induced apoptotic morphology and caspase-3 activity by upregulating phosphorylation of the tropomyosin receptor kinase (Trk) receptor. Inhibition of Trk receptor by K252a altered the neuroprotective effect of both NGF and BDNF whereas inhibition of the p75 neurotrophin receptor (p75NTR) had no effect. Impairment of the PI3K/Akt pathway or overexpression of dominant negative (DN)-Akt abolished the protective effect of both neurotrophins, while active Akt prevented cell death. Moreover, knockdown of Akt by si-RNA was able to block the survival effect of both NGF and BDNF. Thus, the survival action of NGF and BDNF against STS-induced neurotoxicity was mediated by the activation of PI3K/Akt signaling through the Trk receptor.

The effects of β-NGF on proliferation of human pterygium fibroblasts / 眼科研究

Objective Our previous research demonstrated that trkA and p75 receptors of nerve growth factor(β-NGF) are expressed in human pterygium fibroblasts(HPF), and trkA is expressed only in conjunctiva. The purpose of present study was to investigate the effects of β-NGF on proliferation of HPF and analyse the pathogenesis mechanism of pterygium. Methods The HPF specimen was obtained from Union Hospital of Tongji Medical College, Huazhong University of Science and Technology during the surgery. Explant culture technique was used for the primary culture of HPF tissue. The cells of confluenting 80% were collected and digested using 0. 25% tripsin + 0. 02% EDTA (1:1) and the third to fifth generation of cells were utilized in the experiment. Different concentrations of β-NGF was added in medium. Cultured cells were identified using vimentin, keratin and α-SMA. MTT was used to determine the proliferation of HPF after addition of β-NGF. The expression of trkA and p75 in HPF was detected by immumofluorescence method. Cell proliferation also was semi-quantitatively analyzed by detect of expressions of PCNA protein and mRNA in HPF using Western blot and RT-PCR. Results Cultured HPF cells showed the positive responses for vimentin, α-SMA, trkA and p75 but absent reaction for keratin. MTT revealed that the OD value of HPF cells was gradually enhanced with the increase of β-NGF concentration in 12, 24, 48, 72 and 96 hours after β-NGF action with the maximum stimulation at 48 hours. The expression of PCNA protein and mRNA in HPF was significantly different among various concentrations of β-NGF groups(F_(protein) = 24. 980, P = 0. 000; F_(mRNA) = 64. 490, P = 0. 000) and increased from 5 ng/mL β-NGF group through 50 ng/mL β-NGF group in comparison with 0 and 1 ng/mL β-NGF group (P ＜ 0. 05) . Conclusion The findings demonstrate the potential proliferative effect of β-NGF binding to trkA and p75 on HPF.

Expression of nerve growth factors and its receptors in granulosa cells and human ovarian follicle development in polycystic ovarian syndrome / 中国综合临床

Objective To investigate the possible role of nerve growth factors (NGF) and its receptors in ovarian follicle development,and detect the difference between polycystic ovarian symdrome (PCOS) and normal control.Methods Immunohistochemisty was applied to detect the expression of NGF,p75NTR,TrkA in ovarian follicle granulosa cells.Results In 54 cases (including 9 cases of IVM-PCOS,16 cases of IVF-PCOS and 29 cases of IVF-Normal),49 cases showed NGF protein positive in granulose cells with significance difference between groups (P＜0.05),and especially NGF was the strongest expressed factor in IVF-PCOS group but there was no remarkable difference between the other two groups in the expression of NGF.41 were TrkA protein positive,almost all IVF cases were TrkA protein positive while only 2 in IVM and there was no remarkable difference in expression of TrkA between IVF PCOS and IVF Normal(P＞0.05).The cases with stronger expression of NGF or TrkA had higher estradiol level than that of lower expression group (P＜0.05).51 cases had positive expression of p75 NTR protein but there was no significant difference between groups (P＞0.05).Conclusions TrkA is expressed in mature ovarian follicle,and the interaction of NGF-TrkA may be involved in ovarian follicle development,and overexpression of NGF may be associated with PCOS development.

Comparação dos efeitos do gangliosideo GM1 e do fator de crescimento neural (NGF) sobre a expressão de receptor de alta afinidade para NGF, TrkA e insulina em ilhotas pancreaticas isoladas de camundongos NOD (diabetico não obeso) / Comparison of the effect of ganglioside GM1 and the Nerve Growth Factor (NGF) on the expression of receiver of high affinity for NGF, TrkA and insulin in isolated pancreatic islets of NOD mice (non obese diabetic)

O camundongo não obeso diabético (NOD) é caracterizado por desenvolver naturalmente diabetes mellitus tipo 1 (DM-1) com similaridade ao diabetes mellitus tipo 1 em humanos. A manifestação espontânea do diabetes neste modelo animal é caracterizado por infiltração progressiva das ilhotas de Langerhans por células mononucleares linfócitos T (CD4+ e CD8+) e destruição das células ß pancreáticas produtoras de insulina. O fator de crescimento neural (NGF) e algumas citocinas estão associados a regeneração neural, além de atuarem sobre células do sistema imune. Em adição a estes efeitos, NGF age na liberação de insulina pelas células betas das ilhotas pancreáticas, tornando-se foco de interesse com relação as suas propriedades moduladoras no processo inflamatório na ilhota pancreática. O gangliosídeo GM1 liga-se ao receptor de alta afinidade (TrkA) do NGF-ß, mimetizando seus efeitos. No presente trabalho, avaliamos a ação modulatória de GM1 e NGF em cultura de ilhotas pancreáticas, provenientes de camundongos NOD. Foram avaliados por meio de RT-PCR a expressão gênica de NGF-ß, TrkA e insulina e, por ensaio imunoenzimático, a concentração de citocinas IL-1ß, IL-12, TNF-a, INF-y e insulina. Nossos resultados sugerem ação moduladora similar entre GM1 e NGF sobre as ilhotas de NOD não diabéticos e pré-diabéticos. NGF e GM1 aumentam a expressão gênica de NGF e TrkA e diminuem a expressão gênica de insulina em NOD não diabéticos e pré-diabéticos. Além disso, aumentam a liberação de insulina e diminui a de citocinas inflamatórias IL-1ß, IL-12, TNF-a, IFN-y que caracterizam a resposta Th1.

The non-obese diabetic mice (NOD) lineage is characterized by developing type 1 diabetes mellitus (DM-1) naturally, bearing a similarity to DM-1 in human beings. The spontaneous manifestation of diabetes is characterized by gradual infiltration in pancreatic islets by mononuclear cells lymphocytes T (CD4+ and CD8+) and destruction of the ß-cells producers of insulin. One consequence of this effect, is the release of neurotrophins trying modulate the insulin release by the ß cells of pancreatic islets. Thus, the neurotrophins have been the focus of interest in the modulation of the inflammatory process in the pancreatic islets. The ganglioside GM1 binds to the high affinity receptor (TrkA) of the NGF-ß, enhancing its effect. In the present work, we evaluate the immune modulation properties of GM1 and NGF in culture of pancreatic islets from NOD mice. The gene expression of NGF-ß, TrkA and insulin for immune enzymatic assay, the concentration of cytokines IL 1ß, IL-12, TNF-a, IFN-y and insulin were evaluated by RT-PCR and ELISA. Our results suggest similar modulation action between GM1 and NGF on islets of NOD non-diabetic and pre-diabetic. GM1 and NGF action increases the gene expression of NGF and TrkA and the decrease of insulin in mice NOD non-diabetic and pre-diabetic. Moreover, GM1 and NGF increase the insulin release and decrease inflammatory cytokines that characterize the Th1 reply.

Cytosolic accumulation of gammaH2AX is associated with tropomyosin-related kinase A-induced cell death in U2OS cells

Tropomyosin-related kinase A (TrkA) plays an important role in cell survival, differentiation, and apoptosis in various neuronal and nonneuronal cell types. Here we show that TrkA overexpression by the Tet-On system mimics NGF-mediated activation pathways in the absence of nerve growth factor (NGF) stimulation in U2OS cells. In addition, p53 upregulation upon DNA damage was inhibited by TrkA, and p21 was upregulated by TrkA in a p53-independent manner. TrkA overexpression caused cell death by interrupting cell cycle progression, and TrkA-induced cell death was diminished in the presence of its specific inhibitor GW441756. Interestingly, TrkA-mediated cell death was strongly related to gammaH2AX production and poly (ADP-ribose) polymerase cleavage in the absence of DNA damage inducer. In this study, we also reveal thatgammagammaH2AX production by TrkA is blocked by TrkA kinase inhibitors K-252a and GW441756, and it is also significantly inhibited by JNK inhibitor SP600125. Moreover, reduction of cell viability by TrkA was strongly suppressed by SP600125 treatment, suggesting a critical role of JNK in TrkA-induced cell death. We also found that gammaH2AX and TrkA were colocalized in cytosol in the absence of DNA damage, and the nuclear localization of gammaH2AX induced by DNA damage was partly altered to cytosol by TrkA overexpression. Our results suggest that the abnormal cytosolic accumulation of gammaH2AX is implicated in TrkA-induced cell death in the absence of DNA damage.