• BMB Reports
• /
• v.43 no.7
• /
• pp.485-490
• /
• 2010

Neurotrophins regulate many aspects of neuronal function through activation of the high affinity Trk receptors. Shc family proteins are implicated in the coupling of RTK to the Ras/mitogen-activated protein kinase signaling cascade. Here we report that the fourth Shc family member, ShcD, associates with TrkB receptor and regulates BDNF-induced MAPK activation. Yeast two-hybrid assay and Co-IP experiments demonstrate ShcD interacts with TrkB in a kinase-activity-dependent manner. Confocal analysis shows ShcD cololizes well with TrkB in transfected 293T cells. Subsequent mapping experiments and mutational analysis indicate that both PTB and SH2 domains are capable of binding to TrkB and PTB domain binds to TrkB NPQY motif. Furthermore, ShcD is involved in BDNF-induced MAPK activation. In summary, we demonstrate that ShcD is a substrate of TrkB and mediates TrkB downstream signaling pathway.

• The Journal of Korean Physical Therapy
• /
• v.19 no.4
• /
• pp.33-41
• /
• 2007

Purpose: To investigate environmental enrichment and nerve stimulation follows in application times with the change of BDNF & Trk-B receptor in the motor cortex and spinal cord. Methods: Experimental groups were divided into the five groups. Group I: normal control group, Group II: experiment control group, Group III: sciatic never electrical stimulation after MCAO, Group IV: application of only environmental enrichment after MCAO, Group V: never electrical stimulation with environmental enrichment after MCAO. Histologic observation and coronal sections were processed individually in goat polyclonal antibody phosphorylated BDNF and rabbit polyclonal antibody Trk-B receptor. Results: In immunohistochemistric response of BDNF and Trk-B, group II were showed that lower response effect at postischemic 1 days, 3 days, and 7 days. Group V were showed that increase response effect at postischemic 3 days, 7 days and 14 days. Specially showed that the most response effect at postischemic 14 days. In neurobehavioral assessment, group V were significantly difference from other groups on between-subject effects. Conclusion: The above results suggest that combined environmental enrichment with peripheral nerve electrical stimulation in focal ischemic brain injury were more improved that the change of BDNF & Trk-B receptor expression than non treatment.

• Molecules and Cells
• /
• v.39 no.3
• /
• pp.258-265
• /
• 2016

In metastatic breast cancer, the acquisition of malignant traits has been associated with the increased rate of cell growth and division, mobility, resistance to chemotherapy, and invasiveness. While screening for the key regulators of cancer metastasis, we observed that neurotrophin receptor TrkB is frequently overexpressed in breast cancer patients and breast cancer cell lines. Additionally, we demonstrate that TrkB expression and clinical breast tumor pathological phenotypes show significant correlation. Moreover, TrkB expression was significantly upregulated in basal-like, claudin-low, and metaplastic breast cancers from a published microarray database and in patients with triple-negative breast cancer, which is associated with a higher risk of invasive recurrence. Interestingly, we identified a new TrkB-regulated functional network that is important for the tumorigenicity and metastasis of breast cancer. We demonstrated that TrkB plays a key role in regulation of the tumor suppressors Runx3 and Keap1. A markedly increased expression of Runx3 and Keap1 was observed upon knockdown of TrkB, treatment with a TrkB inhibitor, and in TrkB kinase dead mutants. Additionally, the inhibition of PI3K/AKT activation significantly induced Runx3 and Keap1 expression. Furthermore, we showed that TrkB enhances metastatic potential and induces proliferation. These observations suggest that TrkB plays a key role in tumorigenicity and metastasis of breast cancer cells through suppression of Runx3 or Keap1 and that it is a promising target for future intervention strategies for preventing tumor metastasis and cancer chemoprevention.

• International Journal of Oral Biology
• /
• v.39 no.2
• /
• pp.107-114
• /
• 2014

Taste is an important sense in survival and growth of animals. The growth and maintenance of taste buds, the receptor organs of taste sense, are under the regulation of various neurotrophic factors. But the distribution aspect of neurotrophic factors and their receptors in distinct taste cell types are not clearly known. The present research was designed to characterize mRNA expression pattern of neurotrophic factors and their receptors in distinct type of taste cells. In male 45-60 day-old Sprague-Dawley rats, epithelial tissues with and without circumvallate and folliate papillaes were dissected and homogenized, and mRNA expressions for neurotrophic factors and their receptors were determined by RT-PCR. The mRNA expressions of brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT3), receptor tyrosine kinase B (TrkB), exclusion of nerve growth factor (NGF), neurotrophin-4/5 (NT4/5), receptor tyrosine kinase A (TrkA), receptor tyrosine kinase C (TrkC), and p75NGFR were observed in some population of taste cell. In support of this result and to characterize which types of taste cells express NT3, BDNF, or TrkB, we examined mRNA expressions of NT3, BDNF, or TrkB in the $PLC{\beta}2$ (a marker of Type II cell)-and/or SNAP25 (a marker of Type III cell)-positive taste cells by a single taste cell RT-PCR and found that the ratio of positively stained cell numbers were 17.4, 6.5, 84.1, 70.3, and 1.4 % for $PLC{\beta}2$, SNAP25, NT3, BDNF, and TrkB, respectively. In addition, all of $PLC{\beta}2$-and SNAP25-positive taste cells expressed NT3 mRNA, except for one taste bud cell. The ratios of NT3 mRNA expressions were 100% and 91.7% in the SNAP25-and $PLC{\beta}2$-positive taste cells, respectively. However, two TrkB-positive taste cells co-expressed neither $PLC{\beta}2$ nor SNAP 25. The results suggest that the most of type II or type III cells express BDNF and NT3 mRNA, but the expression is shown to be less in type I taste cells.

• Asian-Australasian Journal of Animal Sciences
• /
• v.24 no.3
• /
• pp.336-343
• /
• 2011

The neurotrophins, required for the survival and differentiation of the nervous system, are known to be important for the development of the reproductive tissues. However, the signals initiating the growth of follicles, gamete development, and transport and the development of zygote in the reproductive system of cows remain ambiguous. The purpose of the present study was to identify the transcripts and proteins of Neurotrophin 4 (NT4) and its receptor tyrosine kinase B (TrkB) in bovine reproductive tissues. The transcripts and immunoreactivity of NT4 and TrkB proteins were detected by reverse transcription polymerase chain reaction and western blot analysis. Using immunohistochemistry, the specific immunoreactivity of NT4 and TrkB were detected in the oocytes of primordial follicles and in the growing primary follicles. The NT4 and TrkB immunoreactivity was predominantly observed in granulosa cells, cumulus granulosa cells, cumulus oocyte complexes, theca cells of mature follicles, as well as in the oviduct epithelial cells, uterine gland cell, and epithelium cells of the uterus during the follicular and luteal phases in cows. Expressions of NT4 and TrkB mRNAs were not significantly different among the ovary, oviduct, and uterus of the follicular phase. For the luteal phase, the expression of NT4 mRNA in the ovary was significantly higher than that in the oviduct and uterus, and the expression of TrkB mRNA in the oviduct was significantly higher than that in the ovary and uterus, as determined by fluorescence quantitative reverse transcription polymerase chain reaction. The expression of NT4 mRNA was significantly higher than that of TrkB mRNA in the ovary and uterus, whereas NT4 mRNA expression was lower than that of TrkB mRNA in the oviduct during the luteal phase. The present study hypothesizes that NT4 participates in the regulation of both gonads and extra-gonadal reproductive tissues in cows.

• Journal of Korean Neurosurgical Society
• /
• v.53 no.3
• /
• pp.139-144
• /
• 2013

Objective : Transient anterograde amnesia is occasionally observed in a number of conditions, including migraine, focal ischemia, venous flow abnormalities, and after general anesthesia. The inhalation anesthetic, isoflurane, is known to induce transient anterograde amnesia. We examined the involvement of brain-derived neurotrophic factor (BDNF) and its receptor tyrosine kinase B (TrkB) in the underlying mechanisms of the isoflurane-induced transient anterograde amnesia. Methods : Adult male Sprague-Dawley rats were divided into three groups : the control group, the 10 minutes after recovery from isoflurane anesthesia group, and the 2 hours after recovery from isoflurane anesthesia group (n=8 in each group). The rats in the isoflurane-exposed groups were anesthetized with 1.2% isoflurane in 75% nitrous oxide and 25% oxygen for 2 hours in a Plexiglas anesthetizing chamber. Short-term memory was determined using the step-down avoidance task. BDNF and TrkB expressions in the hippocampus were evaluated by immunofluorescence staining and western blot analysis. Results : Latency in the step-down avoidance task was decreased 10 minutes after recovery from isoflurane anesthesia, whereas it recovered to the control level 2 hours after isoflurane anesthesia. The expressions of BDNF and TrkB in the hippocampus were decreased immediately after isoflurane anesthesia but were increased 2 hours after isoflurane anesthesia. Conclusion : In this study, isoflurane anesthesia induced transient anterograde amnesia, and the expressions of BDNF and TrkB in the hippocampus might be involved in the underlying mechanisms of this transient anterograde amnesia.

• The Journal of Korean Medicine
• /
• v.31 no.3
• /
• pp.66-78
• /
• 2010

Background: Peripheral nerve injuries are a commonly-encountered clinical problem and often result in a chronic pain and severe functional deficits. Objectives: The aim of this study was to evaluate the effects of acupuncture on the descending pain and the recovery of the locomotor function that follows sciatic crushed nerve injury in rats. Method: In order to assess the effects of acupuncture on the descending pain and functional recovery, we investigated the walking track analysis, brain-derived neurotrophic factor (BDNF) and its receptor tyrosine receptor kinase B (TrkB) expression in the sciatic nerve, and on the expressions of c-Fos and nitric oxide synthase in the paraventricular nucleus (PVN) of the hypothalamus and in the ventrolateral periaqueductal gray (vlPAG) region resulting from sciatic crushed nerve injury in rats. Results: Acupuncture treatment at Huantiao (GB30), Yanglingquan (GB34), and Weizhong (BL40) facilitated functional recovery. C-Fos and nitric oxide synthase expressions in the brain and BDNF and TrkB expressions in the sciatic nerve were decreased by acupuncture treatment. The most potent effects of acupuncture were observed at the GB30 acupoint. Conclusion: It is possible that acupuncture can be used for pain control and functional recovery from sciatic nerve injury.

• Journal of Life Science
• /
• v.21 no.8
• /
• pp.1134-1141
• /
• 2011

Transmembrane protein 21 (TMP21) is a member of the p24 cargo protein family and has been shown to modulate ${\alpha}$-secretase-mediated A${\beta}$ production which was specifically observed in the brains of subjects with Alzheimer's disease (AD). In order to investigate whether TMP21 could affect nerve growth factor (NGF) receptor signaling pathway, the alteration of NGF receptors and their downstream proteins were detected in TMP21 over-expressed cells. CMV/hTMP21 vector used in this study was successfully expressed into TMP21 proteins in B35 cells after lipofectamin transfection. Expressed TMP21 proteins induced the down-regulation of ${\gamma}$-secretase complex components including Presenlin-1 (PS-1), PS-2, Nicastrin (NST), Pen-2 and APH-1. Also, the expression level of NGF receptor $p75^{NTR}$ and RhoA were significantly higher in CMV/hTMP21 transfectants than vehicle transfectants, while their levels returned to vehicle levels after NGF treatment. However, the phosphorylation of NGF receptor TrkA was dramtically decreased in NGF No-treated CMV/hTMP21 transfectants compared with vehicle transfectants, and increased in NGF treated CMV/hTMP21 transfectants. In TrkA downstream signaling pathway, the phosphorylation level of ERK was also decreased in CMV/hTMP21 transfectants, while the phosphorylation of Akt was increased in the same transfectants. Furthermore, NGF treatment induced the increase of phosphorylation level of Akt and ERK in CMV/hTMP21 transfectants. Therefore, these results suggested that over-expression of TMP21may simultaneously induce the up-regulation of $p75^{NTR}$/RhoA expression and the down-regulation of TrkA/ERK phosphorylation through the inhibition of ${\gamma}$-secretase activity.

• The Journal of Korean Medicine
• /
• v.31 no.3
• /
• pp.79-97
• /
• 2010

Background: Peripheral nerve injuries are commonly encountered clinical problems and often result in severe functional deficit. Bee venom acupuncture has traditionally been used to treat several inflammatory diseases and chronic pain conditions. Objectives: The aims of this study were to compare the effects of bee venom (general bee venom, BV) and sweet bee venom (allergen-removed bee venom, SBV) acupuncture on the recovery rate of locomotor function, the expression of brain-derived neurotrophic factor (BDNF) in the sciatic nerve, and the expression of c-Fos in the brain following sciatic crushed nerve injury in rats, and to evaluate differences due to administration areas. Method: Walking track analysis, Western blot for BDNF and tyrosine receptor kinase B (TrkB), and immunohistochemistry for c-Fos were performed. In this study, comparative analyses of the effects of BV and SBV acupuncture in relation to administration sites, contralateral side or ipsilateral side, were conducted. Results: In the present result, sciatic function index (SFI) in walking track analysis significantly decreased following sciatic crushed nerve injury. The expressions of BDNF and TrkB in the sciatic nerve increased after induction of sciatic crushed nerve injury. C-Fos expression in the ventrolateral periaqueductal gray (vlPAG) and paraventricular nucleus (PVN) also increased. BV and SBV acupuncture treatment improved the SFI in walking track analysis. Treatment with SBV at 1mg/kg showed more potent enhancing effect on SFI compared to BV. Treatment with 1mg/kg BV or 1mg/kg SBV acupuncture suppressed the BDNF and TrkB expression in the sciatic nerve. BV and SBV acupuncture treatment also suppressed c-Fos expression in the PVN and vlPAG regions. Treatment with SBV at 1mg/kg showed more potent suppressing effect on c-Fos expression compared to BV when injected into the contralateral side of the injured nerve. Generally we could not find significant difference in the effects between contralateral side and ipsilateral side of the injured nerve. Conclusion: We have shown that BV and SBV acupuncture treatment can be used as the effective therapeutic modality to ameliorate the symptoms of sciatic crushed nerve injury.

• BMB Reports
• /
• v.41 no.3
• /
• pp.242-247
• /
• 2008

MSS, a comprising mixture of maesil (Prunus mume Sieb. et Zucc) concentrate, disodium succinate and Span80 (3.6 : 4.6 : 1 ratio) showed a significant improvement of memory when daily administered (460 mg/kg day, p.o.) into the normal rats for 3 weeks. During the spatial learning of 4 days in Morris water maze test, both working memory and short-term working memory index were significantly increased when compared to untreated controls. We investigated a molecular signal transduction mechanism of MSS on the behaviors of spatial learning and memory. MSS treatment increased hippocampal mRNA levels of NR2B and TrkB without changes of NR1, NR2A, ERK1, ERK2 and CREB. However, the protein levels of pERK/ERK and pCREB/CREB were all significantly increased to $1.5{\pm}0.17$ times. These results suggest that the improving effect of spatial memory for MSS is linked to MAPK/ERK signaling pathway that ends up in the phosphorylation of CREB through TrkB and/or NR2B of NMDA receptor.