TrkA is essential components of the high-affinity NGF receptor necessary to mediate biological effects of the neurotrophins NGF. Here we report on the expression of trkA in the cerebral cortex and diencephalon of mongolian gerbils during postnatal development. The expression of trkA was identified by immunohistochemical method. In parietal cortex and piriform cortex, higher levels of trkA-IR (immunoreactivity) were detected at 3 days postnatal (P3) and at P9. Although trkA was not expressed till P3 in the parietal cortex, it was detectable at birth in the piriform cortex. Several regions, such as Layers I, IV & VI, did not show much expression. Layer I showed especially weak labeling. In the hippocampus, thalamus, and hypothalamus, higher levels of trkA-IR were detected at P6 and P12 than earlier days. But trkA was not expressed at birth in the hippocampus, at P3 in the reticular thalamic nucleus (Rt), or neonatally in the dorsomedial hypothalamic nucleus (DM). This data shows that expression of trkA is developmentally regulated and suggests that high affinity neurotrophin-receptors mediate a transient response to neurotrophines in the cerebral cortex and diencephalon during mongolian gerbil brain ontogeny.
Animals ; Animals, Newborn ; Cerebral Cortex/*metabolism ; Diencephalon/*metabolism ; Gerbillinae/*metabolism ; Immunohistochemistry/veterinary ; Nerve Growth Factor/metabolism ; Receptor, trkA/*metabolism

OBJECTIVETo determine the effect of tyrosine kinase A (TrkA) and vascular endothelial growth factor receptor 2 (VEGFR2) in the invasion and metastasis of salivary adenoid cystic carcinoma (SACC).

METHODSThe expression of TrkA and VEGFR2 were detected by immunohistochemical staining in 47 cases of SACC of salivary glands. Clinical data were reviewed by multivariate prognostic analysis.

RESULTSThe positive rate of TrkA and VEGFR2 in SACC was 87.23% (41/47) and 85.11% (40/47) respectively. Express of TrkA and VEGFR2 in perineural invasion and recurrence group were higher than non-perineural invasion and non-recurrence group. Significant difference was found in microvessel density (MVD) and VEGFR2 expression within different groups (P < 0.05). MVD in perineural invasion group (25.14 +/- 2.83) was significantly higher than that in none perineural invasion group (18.81 +/- 1.33) (P < 0.05). MVD in recurrence or metastasis group (26.58 +/- 2.38) was significantly higher than that (19.06 +/- 1.39) in none recurrence nor metastasis group (P < 0.05).

CONCLUSIONPositive correlation between expression of TrkA, VEGFR2 and nerve invasion and vessel metastasis of SACC indicate that TrkA and VEGFR2 play important roles in the invasion and metastasis of SACC. It is possible that TrkA and VEGFR2 could be an aid for evaluating the prognosis of SACC patients.

Carcinoma, Adenoid Cystic ; metabolism ; pathology ; Humans ; Neoplasm Metastasis ; Neoplasm Recurrence, Local ; Receptor, trkA ; metabolism ; Salivary Gland Neoplasms ; metabolism ; pathology ; Vascular Endothelial Growth Factor Receptor-2

OBJECTIVETo investigate the expressions of neurotrophic factors (NTFs) and their receptors in prostate cancer.

METHODSWe detected the expressions of the nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and their receptors TrkA, TrkB and p75 in 35 specimens of prostate cancer by Western blotting, and included 10 specimens of normal prostate tissue from young males that died accidentally.

RESULTSCompared with the control group, the expressions of NGF and p75 were significantly decreased (P < 0.01), while those of BDNF, TrkA and TrkB significantly increased in prostate cancer (P < 0.05).

CONCLUSIONThe changes in the expressions of NTFs and their receptors were related with the pathogenesis and progression of prostate cancer, which may be considered as reference indexes for the diagnosis of the disease.

Adolescent ; Adult ; Aged ; Brain-Derived Neurotrophic Factor ; metabolism ; Case-Control Studies ; Humans ; Male ; Middle Aged ; Nerve Growth Factors ; metabolism ; Prostatic Neoplasms ; metabolism ; pathology ; Receptor, Nerve Growth Factor ; metabolism ; Receptor, trkA ; metabolism ; Receptor, trkB ; metabolism ; Young Adult

OBJECTIVETo investigate the expressions and action mechanisms of nerve growth factor (NGF) receptors TrkA and p75NTR in the oncogenesis and progression of prostate cancer (PCa).

METHODSUsing immunohistochemistry, we detected the expressions of TrkA and p75NTR in 62 PCa and 35 benign prostatic hyperplasia (BPH) samples, and conducted statistical analysis on the basis of clinical data.

RESULTSIndependent-samples t-test showed that, along with poorer tissue differentiation or higher clinical stage of PCa, the expression of TrkA was significantly up-regulated, that of p75NTR remarkably down-regulated, and the expression ratio of TrkA to p75NTR markedly increased. The TrkA/p75NTR ratio was 0.32 in the BPH, 0.52 in the PCa tissue with Gleason score of 6, 1.65 in the PCa tissue with Gleason score of 7, 5.75 in the PCa tissue with Gleason score ≥ 8, 0.89 in the clinical stage of pT2, 1.5 in pT3 a, 3.75 in pT3b, and 7.00 in pTxN1.

CONCLUSIONThe abnormally increased expression ratio of TrkA to p75NTR might be one of the essential features of malignant transformation of prostate cells. A higher TrkA/p75NTR expression ratio may be associated with a lower tissue differentiation, a higher clinical stage or Gleason score, and therefore a poorer prognosis.

Humans ; Immunohistochemistry ; Male ; Neoplasm Grading ; Neoplasm Staging ; Nerve Tissue Proteins ; metabolism ; Prognosis ; Prostatic Hyperplasia ; pathology ; Prostatic Neoplasms ; pathology ; Receptor, trkA ; metabolism ; Receptors, Nerve Growth Factor ; metabolism ; Up-Regulation

Tyrosine kinase A (TrkA)is an essential component of the high affinity nerve growth factor (NGF) receptor necessary to the mediate the biological effects of the neurotrophins, NGF. This study examined the distribution of TrkA-immunoreactivity (IR)cells in the postnatal rat cerebral cortex and the changes that occur in postnatal development as a result of the expression of this protein. TrkA-IR was detected at postnatal day (PD)3, PD6, PD9 and PD15. Base upon their somatodendritic morphology, the most commonly labeled cell type was the pyramidal neurons. At PD3 and PD6, layer I, II, III and V was immunopositive for TrkA, at PD9, not only at layer I, II, III, and V but also at layer VI. At PD15, the TrkA-positive cells were distributed in all layers. These TrkA-positive cells were not detected at PD0. In contrast, there was significant increase in the percentage of cells exhibiting TrkA-IR with development and the highest level was detected at PD15. These results suggest that the cerebral cortex expresses TrkA strongly during the postnatal period. Moreover, the postnatal development-related increase in the expression of TrkA-cells shows that NGF may have a trophic effect on these cerebral cortex neurons from the postnatal period.
Animals ; Animals, Newborn ; Cerebral Cortex/*growth&development/*metabolism ; Gene Expression Regulation, Developmental/*physiology ; Neurons/*metabolism ; Rats ; Rats, Sprague-Dawley ; Receptor, trkA/*metabolism

OBJECTIVE: To observe the effect of electroacupuncture (EA) at "Zusanli" (ST 36) on duodenal mast cells, nerve growth factor (NGF) and neurotrophic tyrosine kinase receptor type 1 (NTRK1), and to explore the mechanism of electroacupuncture at Zusanli (ST 36) on functional dyspepsia (FD). METHODS: Sixty SPF-grade 10-day-old SD rats were randomly divided into a normal group, a model group, a ketotifen group and an EA group, 15 rats in each group. The FD model was prepared by iodoacetamide combined with rat tail clamping method in the model group, the ketotifen group and the EA group. The rats in the ketotifen group were injected intraperitoneally with ketotifen (1 mg•kg^-1•d^-1) for 7 days; the rats in the EA group were treated with EA at bilateral "Zusanli" (ST 36), with disperse-dense wave, frequency of 2 Hz/50 Hz and intensity of 0.5 mA, 20 min each time, once a day for 14 days. The gastric emptying rate and small intestinal propulsion rate in each group were observed; the morphology of duodenal mucosa was observed by HE staining; the toluidine blue staining was used to observe the number and degranulation of mast cells in duodenal mucosa; the protein and mRNA expressions of NGF, NTRK1 in duodenum were detected by Western blot and real-time PCR; the level of interleukin-1β (IL-1β) in duodenum was measured by ELISA. RESULTS: Compared with the normal group, the gastric emptying rate and small intestinal propulsion rate in the model group were decreased (P<0.01); compared with the model group, the gastric emptying rate and small intestinal propulsion rate in the ketotifen group and the EA group were increased (P<0.01); the small intestinal propulsion rate in the EA group was higher than that in the ketotifen group (P<0.01). In the model group, local defects in duodenal mucosa were observed with a small amount of inflammatory cell infiltration; no obvious abnormality was found in duodenal mucosa of the other groups. Compared with the normal group, the mast cells of duodenal mucosa in the model group were increased significantly with significant degranulation; compared with the model group, the mast cells of duodenal mucosa in the ketotifen group and the EA group were decreased significantly, and the degranulation was not obvious. Compared with the normal group, the protein and mRNA expressions of NGF, NTRK1 as well as the level of IL-1β in duodenum in the model group were increased (P<0.01); compared with the model group, the protein and mRNA expressions of NGF, NTRK1 as well as the levels of IL-1β in duodenum in the ketotifen group and the EA group were decreased (P<0.01, P<0.05); compared with the ketotifen group, the mRNA expression of NGF, as well as the protein and mRNA expressions of NTRK1 in duodenum in the EA group were decreased (P<0.05, P<0.01). CONCLUSION EA at "Zusanli" (ST 36) could inhibit the activation of duodenal mast cells and regulate the expressions of NGF and its receptor to improve the low-grade inflammatory response of duodenum, resulting in treatment effect on FD.
Acupuncture Points ; Animals ; Duodenum/metabolism* ; Dyspepsia/therapy* ; Electroacupuncture ; Ketotifen ; Mast Cells/metabolism* ; Nerve Growth Factor/metabolism* ; RNA, Messenger ; Rats ; Rats, Sprague-Dawley ; Receptor, trkA/genetics*

OBJECTIVETo study the responses of different pancreatic cancer cells to stimulations by nerve growth factor (NGF) and explore the role of Trk-A in such responses.

METHODSFive pancreatic cancer cell lines (MIA-PaCa-2, PANC-1, SW-1990, AsPC-1, and BxPC-3) were exposed to different concentrations of NGF (0, 4, 20, 100, and 500 ng/ml). MTT and Matrigel invasion method were used to observe the changes in the cell proliferation and invasion ability. Trk-A expression in these cells was detected by PCR and Western blotting, and the relations of Trk-A expression to the cell proliferative and invasive abilities following NGF treatment were analyzed.

RESULTSNGF at 100 ng/ml most obviously stimulated the cell proliferation, and PANC-1 cells showed the highest while AsPC-1 cells showed the least sensitivity to 100 ng/ml NGF stimulation. Matrigel invasion test showed that NGF enhanced the invasiveness of PANC-1 and MIA-PaCa-2 cells but produced only limited effect on AsPC-1 cells; the effect of NGF was completely inhibited by the Trk-A inhibitor CEP701. The expression levels of Trk-A mRNA and protein were the highest in PANC-1 cells and the lowest in AsPC-1 cells.

CONCLUSIONNGF can enhance the proliferation and invasiveness of pancreatic cancer cells, and this effect is possibly mediated by Trk-A protein.

Cell Line, Tumor ; Cell Movement ; drug effects ; Cell Proliferation ; drug effects ; Humans ; Neoplasm Invasiveness ; Nerve Growth Factor ; pharmacology ; Pancreatic Neoplasms ; metabolism ; pathology ; Receptor, trkA ; genetics ; metabolism

Nerve growth factor (NGF) is mainly secreted by the neuroglia cells, which can exert biological effect through its receptors on the specific target cell surface. NGF is closely related to neurocyte growth, differentiation and apoptosis. As a neurotropic virus, HSV-1 an easily lead to neurocyte, neuroglia cells death or apoptosis. In this study, the U251 human glioma cells were chosen as target cells to study the change of NGF and its receptors in the apoptosis process of HSV-1 infection. Our results showed that U251 cells were permissive to HSV-1 replication. In the apoptosis process of HSV-1 infected U251 cells, the expression of both NGF and P75NTR increased and then decreased, while the expression of TrkA decreased gradually. These result indicated that HSV-1 was able to induce the abnormal expression of NGF and its receptors in U251 cells.
Apoptosis ; Cell Line, Tumor ; Gene Expression ; Glioma ; genetics ; metabolism ; physiopathology ; virology ; Herpes Simplex ; genetics ; metabolism ; physiopathology ; virology ; Herpesvirus 1, Human ; genetics ; physiology ; Humans ; Nerve Growth Factor ; genetics ; metabolism ; Receptor, Nerve Growth Factor ; genetics ; metabolism ; Receptor, trkA ; genetics ; metabolism ; Virus Replication

OBJECTIVETo study the mechanism of brain development delay in rats with intrauterine growth retardation (IUGR) by examining the expression of nerve growth factor (NGF) and tyrosine kinase receptor A (Trk A) in the brain.

METHODSThirty-two pregnant rats were randomly fed with a normal diet (control group) or lower protein diet (IUGR group) during pregnancy (n=16 each). The pup rats were sacrificed at 0, 7, 14 or 21 days after birth. The protein levels of NGF and TrkA in the brain were determined by Western blot and immunohistochemistry staining.

RESULTSThe levels of NGF and TrkA in the brain in pup rats of the IUGR group were significantly lower than those in the control group 0, 7, 14 and 21 days after birth.

CONCLUSIONSThe decreased expression of protein levels of NGF and TrkA in the brain might be one of the causes of brain development delay in IUGR rats.

Animals ; Birth Weight ; Brain Chemistry ; Female ; Fetal Death ; epidemiology ; Fetal Growth Retardation ; epidemiology ; metabolism ; Immunohistochemistry ; Nerve Growth Factor ; analysis ; Pregnancy ; Rats ; Rats, Wistar ; Receptor, trkA ; analysis

OBJECTIVE: To determine the expression of nerve growth factor (NGF), tyrosine kinase receptor A (trkA), and pan-neurotrophin receptor (p75) in the lung tissues in asthmatic rats, and to explore their effects on the airway inflammation. METHODS: Thirty-two SD rats were randomly divided into 4 groups: the control, asthma, NGF and anti-NGF groups. The asthmatic model was established by the inhalation and injection of ovalbumin. The total cell count and differential cell count in the bronchoalveolar lavage fluid (BALF) were performed. The pathologic changes in the lung tissues of the 4 groups was detected by HE staining. The NGF mRNA expression in the lung tissues of the asthma and control groups was determined by reverse transcription-polymerase chain reaction (RT-PCR). The changes of trkA and p75 mRNA expressions in the lung tissues in the 4 groups were also investigated by RT-PCR. RESULTS: Compared with the control group, the BALF total cell, the BALF eosinophils (Eos), and the BALF lymphocytes (Lyms) significantly increased (All P <0. 001) in the asthma group; and the lung tissues of the asthma group had more infiltrating inflammatory cells. Not only the expression of NGF mRNA, but also its receptors trkA and p75 mRNA in the lung tissues were significantly higher in the asthma group than those in the control group (All P < 0.01). Positive correlation was found between the expression of NGF mRNA and the BALF total cell, the BALF Lyms in the asthma group. Compared with the asthma group, the total cell, the Eos, and the lyms in BALF in the NGF group significantly increased (All P < 0.01), and the lungs of the NGF group had apparent inflammatory changes. The expre-ssions of p75 and trkA mRNA were enhanced significantly (All P < 0.05). Compared with the asthma group, the total cell, the Eos, and the lyms in BALF in the anti-NGF group significantly decreased (All P < 0.001), and the lungs of the anti-NGF group showed alleviative inflammatory changes. The expre-ssions of p75 and trkA mRNA significantly decreased (All P < 0.01). CONCLUSION In lungs of asthmatic rats, the elevated expression of NGF mRNA is closely related to the airway inflammation. NGF can upregulate the expressions of p75 and trkA mRNA in asthmatic rats, and then may promote their role in the airway neuronal inflammation in asthma.
Animals ; Asthma ; chemically induced ; metabolism ; Bronchitis ; metabolism ; Lung ; metabolism ; Male ; Nerve Growth Factor ; metabolism ; Ovalbumin ; RNA, Messenger ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Receptor, trkA ; metabolism ; Receptors, Nerve Growth Factor ; metabolism