Elevated Levels of Naturally-Occurring Autoantibodies Against the Extracellular Domain of p75NTR Aggravate the Pathology of Alzheimer's Disease / 神经科学通报·英文版

The extracellular domain (p75ECD) of p75 neurotrophin receptor (p75NTR) antagonizes Aβ neurotoxicity and promotes Aβ clearance in Alzheimer's disease (AD). The impaired shedding of p75ECD is a key pathological process in AD, but its regulatory mechanism is largely unknown. This study was designed to investigate the presence and alterations of naturally-occurring autoantibodies against p75ECD (p75ECD-NAbs) in AD patients and their effects on AD pathology. We found that the cerebrospinal fluid (CSF) level of p75ECD-NAbs was increased in AD, and negatively associated with the CSF levels of p75ECD. Transgenic AD mice actively immunized with p75ECD showed a lower level of p75ECD and more severe AD pathology in the brain, as well as worse cognitive functions than the control groups, which were immunized with Re-p75ECD (the reverse sequence of p75ECD) and phosphate-buffered saline, respectively. These findings demonstrate the impact of p75ECD-NAbs on p75NTR/p75ECD imbalance, providing a novel insight into the role of autoimmunity and p75NTR in AD.

Effect of Aloe vera on the expression of nerve factors, p75 and TrkA receptors in the hippocampus of diabetic rats / Efecto del Aloe vera sobre la expresión de factores de crecimiento nervioso, Receptores p75 y TrkA en el hipocampo de ratas diabéticas

SUMMARY: Diabetes mellitus can lead to structural disorders in the brain. One of the most common complications of diabetes, diabetic neuropathy is associated with central nervous system disorders. Aloe vera has anti-diabetic, antioxidant, and neuroprotective effects. This study was designed to evaluate the effects of Aloe vera gel on the hippocampus changes as well as the expression of nerve growth factor and receptors TrkA and P75 in the hippocampus of streptozotocin (STZ)-induced diabetic rats. 25 male Wistar rats were randomly divided into 5 groups including: control (normal saline), diabetic (normal saline), Aloe vera gel (400 mg/kg/day; gavage), diabetic + Aloe vera gel (400 mg/kg/day; gavage) and diabetic + insulin NPH (10 IU/kg/day; subcutaneous). Experimental diabetes was induced by streptozotocin injection (60 mg/kg; intraperitoneal). All groups treated for 8 weeks. At the end of treatment course, the rat brains were removed for measuring the expression of nerve growth factor, p75 and TrkA receptors were evaluated in the hippocampus. Diabetes induction after 8 weeks caused NGF and P75 expression levels in the diabetic group than other groups significantly increased (p<0.05). The TrkA receptor expression in the diabetic group compared with the control had a significant reduction (p<0.05). On the other hand in the diabetic group receiving Aloe vera gel expression of NGF and P75 expression levels compared to the diabetic group was significantly reduced (p<0.05) and the TrkA receptor expression compared with the diabetic group had a significant increase (p<0.05). The results showed that oral administration of Aloe vera gel in diabetic rats ameliorates diabetes-induced hyperglycemia. On the other hand, Aloe vera gel cause modulation of the expression of NGF neurotrophic factor via increased expression of TrkA receptor-specific and non-specific receptor down-regulation of P75 in the hippocampus of STZ-induced diabetic rats.

RESUMEN: La diabetes mellitus puede provocar trastornos estructurales en el cerebro. Es una de las complicaciones más comunes de la diabetes y la neuropatía diabética y está relacionada con trastornos del sistema nervioso central. El Aloe vera tiene efectos antidiabéticos, antioxidantes y neuroprotectores. Este estudio fue diseñado para evaluar los efectos del gel de Aloe vera en los cambios del hipocampo, así como la expresión del factor de crecimiento nervioso y los receptores TrkA y P75 en el hipocampo de ratas diabéticas inducidas por estreptozotocina (STZ). Se dividieron al azar 25 ratas Wistar macho en 5 grupos de: control (solución salina normal), diabéticos (solución salina normal), gel de Aloe vera (400 mg / kg / día; sonda), diabéticos + gel de Aloe vera (400 mg / kg / día; sonda) y diabéticos + insulina NPH (10 UI / kg / día; subcutánea). La diabetes experimental fue inducida por inyección de estreptozotocina (60 mg / kg; intraperitoneal). Todos los grupos fueron tratados durante 8 semanas. Al final del tratamiento, se extrajeron los cerebros de las ratas para medir la expresión del factor de crecimiento nervioso y se evaluaron los receptores p75 y TrkA en el hipocampo. La inducción de diabetes después de 8 semanas provocó que los niveles de expresión de NGF y P75 en el grupo de diabéticos aumentaran significativamente en comparación con otros grupos (p <0,05). La expresión del receptor TrkA en el grupo diabético comparado con el control tuvo una reducción significativa (p <0,05). Por otro lado, el grupo de ratas diabéticas que recibieron la expresión en gel de Aloe vera de NGF y los niveles de expresión de P75 en comparación con el grupo de ratas diabéticas se redujo significativamente (p <0,05) y la expresión del receptor de TrkA en comparación con el grupo de ratas diabéticas tuvo un aumento significativo (p <0,05). Los resultados mostraron que la administración oral de gel de Aloe vera en ratas diabéticas mejora la hiperglucemia inducida por la diabetes. Por otro lado, el gel de Aloe vera causa modulación de la expresión del factor neurotrófico NGF a través del aumento de la expresión de receptor TrkA específico y no específico y regulación negativa del receptor de P75 en el hipocampo de ratas diabéticas inducidas por STZ.

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.

Changes in expression of BDNF and its receptors TrkB and p75NTR in the hippocampus of a dog model of chronic alcoholism and abstinence

Chronic ethanol consumption can produce learning and memory deficits. Brain-derived neurotrophic factor (BDNF) and its receptors affect the pathogenesis of alcoholism. In this study, we examined the expression of BDNF, tropomyosin receptor kinase B (TrkB) and p75 neurotrophin receptor (p75NTR) in the hippocampus of a dog model of chronic alcoholism and abstinence. Twenty domestic dogs (9-10 months old, 15-20 kg; 10 males and 10 females) were obtained from Harbin Medical University. A stable alcoholism model was established through ad libitum feeding, and anti-alcohol drug treatment (Zhong Yao Jie Jiu Ling, the main ingredient was the stems of watermelon; developed in our laboratory), at low- and high-doses, was carried out. The Zhong Yao Jie Jiu Ling was effective for the alcoholism in dogs. The morphology of hippocampal neurons was evaluated using hematoxylin-eosin staining. The number and morphological features of BDNF, TrkB and p75NTR-positive neurons in the dentate gyrus (DG), and the CA1, CA3 and CA4 regions of the hippocampus were observed using immunohistochemistry. One-way ANOVA was used to determine differences in BDNF, TrkB and p75NTR expression. BDNF, TrkB and p75NTR-positive cells were mainly localized in the granular cell layer of the DG and in the pyramidal cell layer of the CA1, CA3 and CA4 regions (DG>CA1>CA3>CA4). Expression levels of both BDNF and TrkB were decreased in chronic alcoholism, and increased after abstinence. The CA4 region appeared to show the greatest differences. Changes in p75NTR expression were the opposite of those of BDNF and TrkB, with the greatest differences observed in the DG and CA4 regions.

The capacity and biological characteristic of the p75 neurotrophin receptor-positive ectomesenchymal stem cell in vitro / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the biological characteristic of ectomesenchymal stem cells (EMSC) and the differentiation of p75(+)EMSC and influencing factors.</p><p><b>METHODS</b>The immunohistochemical staining method was used to observe the migration of EMSC from 12.5 d SD rat embryonic facial process. Then EMSC was labeled by p75 neurotrophin receptor, and the cell cycle and stem cell surface antigens of the p75(+) EMSC was examined.</p><p><b>RESULTS</b>Immunohistochemical staining showed that stem cells from the cranial neural crest migrated to embryonic rat facial process at 12.5 days. The sorting rate of the p75(+)EMSC was 6.1%. The proportion of the p75(+)EMSCs' S/G2/M phase was stable during subculture. The special substances CD29, CD146 and Stro-1 were marked for p75(+)EMSC, and the expressions of the markers were all higher (> 90%) in p75(+) EMSC.</p><p><b>CONCLUSIONS</b>The embryonic tooth did not start to grow on the conception 12.5 days of SD rats. The p75(+) EMSC after sorting had stable proliferation ability and had stem cell characteristics during subculture and didn't start differentiation.</p>

Experimental study on the effects of the nerve growth factor regulating calcitonin gene-related peptide in promoting the proliferation of MG-63 in vitro / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the nerve growth factor (NGF) regulating the expression of calcitonin gene-related peptide (CGRP) in promoting the proliferation of osteoblast-like cell (MG-63) and thus illustrate the mechanism of the NGF in wound healing.</p><p><b>METHODS</b>Different concentrations of NGF were used to stimulate MG-63. The expression of CGRP was detected by real-time quantitative polymerase chain reaction (RT-QPCR) and enzyme-linked immunosorbent assay after 1, 2, 3, and 4 days. The proliferation of MG-63 was detected by cell counting kit-8 (CCK-8). The expression of CGRP mRNA and the proliferation of MG-63 were then detected by RT-QPCR and CCK-8 after adding the NGF receptor blocker.</p><p><b>RESULTS</b>Compared with the blank control group, the expression of CGRP significantly increased by stimulating the NGF. The expression of CGRP was positively related to the concentration of NGF (P<0.05). Moreover, the expression of CGRP increased by prolonging the NGF stimulation time. The proliferation of MG-63 increased after stimulating the NGF (P<0.05). After adding the NGF receptor blocker, the expression of CGRP and the proliferation of MG-63 correspondingly decreased (P<0.05).</p><p><b>CONCLUSION</b>NGF can up-regulate the expression of CGRP and increase the proliferation of MG-63. Therefore, NGF plays a significant role in wound healing.</p>

Effect of neurotrophin p75 receptor activation on transmural dispersion repolarization in rabbits with myocardial infarction / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To elucidate the effect of neurotrophin p75 receptor (p75NTR)on transmural dispersion repolarization (TDR) of the layers of left ventricular myocytes in rabbits with myocardial infarction (MI).</p><p><b>METHODS</b>Forty Japanese rabbits were divided into four groups (n = 10): (1) Sham group, (2) Heald myocardial infarction (HMI) group, (3) p75 NTR activation group, (4) p75 NTR inhibition group. Cardiomyocytes were isolated with enzyme digestion and the currents were recorded by whole-cell patch-clamp technique.</p><p><b>RESULTS</b>Compared with those in the sham group, the duration of 90% action potential repolarization (APD90) and transmural dispersion repolarization of three layers of left ventricular myocytes were obviously raised (P < 0.05). But significant reduction was observed in p75NTR(-) group. Current densities of Ito and I(Ks, tail) in the p75NTR(+) group and HMI group were significantly reduced (P < 0.05), especially in mid myocytes. And no obvious changes were observed in p75NTR(-) group.</p><p><b>CONCLUSION</b>Activation of p75NTR(+) increases transmural dispersion repolarization, which may lead to the incidence of arrhythmia.</p>

Expression of P75NTR in the testis of nestin-GFP transgenic mice / 中华男科学杂志

<p><b>OBJECTIVE</b>To explore the P75NTR expression in the mouse testis and its relationship with nestin.</p><p><b>METHODS</b>We observed the location of the expressions of P75NTR and nestin in the testis of the nestin-GFP transgenic mouse on postnatal day (PND) 5, 14 and 30 using immunofluorescence, and detected the expression levels of P75NTR in the testicular tissue of mice in different age groups by real-time quantitative PCR (RTqPCR) and flow cytometry. Then we cultured the P75NTR positive cells in neural stem cell culture medium and observed their neuronal differentiation capacity by orientation differentiation.</p><p><b>RESULTS</b>Immunofluorescence showed the expressions of P75NTR and nestin in the Leydig cells of the mouse testis. RTqPCR and flow cytometry exhibited the peak of the P75NTR expression on PND 14. The positive rates of P75NTR were (2.88 +/- 0.52), (9.54 +/- 1.81) and (2.63 +/- 0.43)% on PND 5, 14 and 30, respectively. The P75NTR positive cells obtained also expressed nestin and P75NTR and had the capacity of neuronal differentiation.</p><p><b>CONCLUSION</b>P75NTR and nestin are co-expressed in the Leydig cells of the mouse testis, and the P75NTR positive cells have the ability of neural differentiation, which is presumably attributed to neural crest cells.</p>

Precautionary effects of Red Liriope platyphylla on NGF secretion and Abeta42 deposition under the preclinical stage of Alzheimer's disease in Tg2576 mice / 한국실험동물학회지

Red Liriope platyphylla (RLP) has been manufactured from Liriope platyphylla (L. platyphylla, LP) roots using steaming process and investigated as a curative agent for treatment of diabetes, obesity and neurodegenerative disorders. To examine the precautionary effects of aqueous extract RLP (AEtRLP) on the preclinical stages of Alzheimer's Disease (AD), alterations of the key factors influencing AD were investigated in Tg2576 mice after AEtRLP7 treatment for 4 months. Abeta-42 peptides level was significantly decreased in the brain of AEtRLP7-treated Tg2576 mice compared to vehicle-treated Tg2576 mice, although significant differences on improving behavioral defects were not observed in the same group. The concentration of nerve growth factor (NGF) in serum was also higher in AEtRLP7-treated Tg2576 mice than vehicle-treated Tg2576 mice. However, the phosphorylation of TrkA and Erk among the downstream effectors of the high affinity NGF receptor was significantly lower in AEtRLP7-treated Tg2576 mice. A similar pattern was observed in the expression level of downstream effectors within low affinity NGF receptor. Overall, these results suggest that AEtRLP7 can contribute to preventing the production and deposition of Abeta-42 peptides during the early progression stage of AD in the brain of Tg2576 mice through increased NGF secretion.

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.

Effects of Red Liriope platyphylla on NGF secretion ability, NGF receptor signaling pathway and gamma-secretase components in NSE/hAPPsw transgenic mice expressing Alzheimer's Disease / 한국실험동물학회지

Liriope platyphylla (LP) has long been regarded as a curative herb for the treatment of diabetes, asthma, and neurodegenerative disorders. To examine the therapeutic effects of Red LP (RLP) manufactured by steaming process on neurodegenerative disorders, significant alteration of the key factors influencing Alzheimer's Disease (AD) was detected in NSE/hAPPsw transgenic (Tg) mice after RLP treatment. The concentration of nerve growth factor (NGF) in serum increased in RLP-treated NSE/hAPPsw Tg mice compared with vehicle-treated Tg mice. However, downstream effectors of the NGF receptor signaling pathway, including TrkA and p75NTR proteins, were suppressed in RLP-treated NSE/hAPPsw Tg mice. Especially, Tg mice showed decreased levels of TrkA, p75NTR, and RhoA expression. Production of Abeta-42 peptides was lower in RLP-treated NSE/hAPPsw Tg mice than in vehicle-treated Tg mice. Further, analysis of gamma-secretase components showed that Abeta-42 peptide expression was downregulated. Of the four components, the expression of APH-1 and Nicastrin (NCT) decreased in RLP-treated NSE/hAPPsw Tg mice, whereas expression of PS-2 and Pen-2 was maintained or increased within the same group. Overall, these results suggest that RLP can help relieve neurodegenerative diseases, especially AD, through upregulation of NGF secretion ability, activation of NGF signaling pathway, downregulation of Abeta-42 peptide deposition, and alteration of gamma-secretase components.

P75 neurotrophin receptor mRNA sequential expression and significance after Cauda equina compression in rats / 中国骨伤

<p><b>OBJECTIVE</b>To observe the mRNA expression of p75NTR (p75 neurotrophin receptor) and the amount of neuronal cells apoptosis in lumbar-sacral spinal cord at different time points after the acute cauda equina compression in rats and to explore their correlation.</p><p><b>METHODS</b>Sixty adult female Sprague Dawley(SD) rats were randomly divided into the normal control group and the compression groups. The acute cauda equine compression model was established as placing a silicon gel rubber at L(3,4) level of the vertebral canal which represented about 70% to 80% compression to the cross section. The whole L(1,2) level of spinal cords were harvested at 1, 3, 5, 7, 14, 28 d after operation in compression group. Tunel method was applied to observe cell apoptosis and RT-PCR was used to detect the p75NTR mRNA expression. SPSS 13.0 statistical software was adopted to help analysis.</p><p><b>RESULTS</b>In the compression group, both the nerve cells apoptosis and the p75 mRNA expression existed the trend of low-high-low synchronally compared with the control group, there was a significant difference (P < 0.05) among comprssion groups at different time points,there was a significant difference in changes (P < 0.05). p75NTR of mRNA expression and lumbosacral nerve cells apoptosis was in a positive correlation.</p><p><b>CONCLUSION</b>After acute cauda equina compression, p75NTR mRNA expression is closely related to the neuronal apoptosis, which plays an important role in the molecular mechanism of the CES.</p>

Influence of p75 neurotrophin receptor knockout on the regeneration of facial nerves after crush injury in mouse / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the role of p75 neurotrophin receptor (p75NTR) in the regeneration of facial nerve crush injury.</p><p><b>METHODS</b>In p75NTR knockout mice and wild type mice, the regenerating fibres in the facial nerve were also labelled by an anterograde tracer cholera toxin B (CTB). The next day after injury of facial nerve, CTB was injected into the trunk of the nerve in the proximal side of the crush, and then anterograde tracing and immunohistochemistry were used to examine the regeneration of axons after facial nerve crush injury. In p75NTR knockout mice and wild type mice, the facial nerves on one side were crushed and regenerating neurons in the facial nerve nucleus were labelled by Fast Blue. The facial nerve trunk was cut in the bifurcated region in the 4th day after injury and the stump was inserted into a small polymer tube containing Fast Blue. Retrograde tracing and labling motoneuron counting were used to examine the survival of motoneurons in the facial nerve nucleus after facial nerve crush injury.</p><p><b>RESULTS</b>The results showed that the axonal growth of injured axons in the facial nerve of p75NTR knockout mice was significantly retarded. The number of regenerated neurons in the facial nerve nucleus in p75NTR knockout mice was significantly reduced (P < 0.05). Immunohistochemical staining of regenerating axons also showed the reduction in nerve regeneration in p75NTR knockout mice (P < 0.01).</p><p><b>CONCLUSION</b>p75NTR plays an important role in the regeneration of injured peripheral nerves after injury.</p>

Expressions of neurotrophic factors and their receptors in prostate cancer / 中华男科学杂志

<p><b>OBJECTIVE</b>To investigate the expressions of neurotrophic factors (NTFs) and their receptors in prostate cancer.</p><p><b>METHODS</b>We 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.</p><p><b>RESULTS</b>Compared 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).</p><p><b>CONCLUSION</b>The 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.</p>

Effect of HSV-1 infection on NGF and its receptor expression in human glioma cells / 病毒学报

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.

Are CD133 and CD271 useful in positive selection to enrich umbilical cord blood mesenchymal stem cells? / 中国实验血液学杂志

It is well accepted that umbilical cord blood has been a source for mesenchymal stem cells. However, there was less success in culturing these cells by using traditional method. Lots of studies showed that CD271 (low affinity nerve growth factor receptor LNGFR) and CD133 could be used to positive sort of bone marrow-derived mesenchymal stem cells (MSC) in recent years. The present study was designed to explore whether the method of positive sorting of umbilical cord blood-derived MSC (UCB-MSC) was effective by using CD271 and CD133 immunomagnetic beads. The ability of forming CFU-F and differentiation capacity of the four kinds of cells, namely CD271+, CD271-, CD133+ and CD133- were analysed. The results indicated that the purities of immunomagnetically selected CD271+ and CD133+ cells were (87.58±0.48)% and (89.89±8.10)% respectively. More than 99% of CD271+ and CD133+ cells expressed CD34 and CD45, the markers of hematopoietic stem cells. CFU-F assay showed that CD271+ and CD133+ cells could not form any CFU-F and only few single fibroblast-like cells could be found in the dishes. However, part of the negative samples (27%) could form CFU-F. Phenotype of cells (passage 3) isolated by the two methods was the same, that was CD34-, CD45-, CD14-, CD29+, CD44+, CD73+, CD105+ and CD90+. They both had osteogenic and adipogenic differentiation potential. It is concluded that nearly all the CD271 and CD133 positive cells are hematopoietic cells, MSC can be effectively collected by negative selection with immunomagnetic beads against CD271 and CD133.

Study on reversion of malignant phenotype of glioma by siRNA targeting p75 neurotrophin receptor / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the therapeutic efficacy of siRNA fragments silencing p75 neurotrophin receptor (p75(NTR)), which may be a key regulator of glioma cell apoptosis and invasion.</p><p><b>METHODS</b>The siRNA sequence fragments targeting p75(NTR) were designed and transferred into human glioma cell line U251. RT-PCR and immunocytochemistry method were used to explore the expression of p75(NTR) mRNA and protein. Cell adhesion assay was employed to detect cellular adhesion ability, and soft agar clone formation assay was adopted to identify oncogenicity, and a U251 glioma model was established in nude mice. The intracranial tumor volume was detected by MRI. The expression of p75(NTR), NGF and cyclin D2 were identified using immunohistochemistry. Cell apoptosis was detected by apoptosis kit in situ.</p><p><b>RESULTS</b>The siRNA fragments targeting p75(NTR) were capable of decreasing mRNA and protein expression of p75(NTR) in U251 glioma cell line. Both the cellular adhesion ability and oncogenicity were weakly relevant. The p75(NTR) expression level was negatively correlated with cyclin D2 and apoptosis, and positively correlated with NGF expression. The siRNA sequence fragments targeting p75(NTR) were effective in decreasing the gross volume of tumor; prolonged the survival time of mice, and the edge of tumor was much sharper than that of the control group.</p><p><b>CONCLUSIONS</b>The gene silencing technique by siRNA targeting p75(NTR) is capable of decreasing tumor invasion and cell proliferation as well as inducing cell apoptosis. It is expected to be a new choice for glioma gene therapy.</p>

Expressions of neurotrophin factor receptor in spiral ganglion cell of cisplatin-induced ototoxicity / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To investigate the effects of high-affinity tyrosine kinase receptors TrkB, TrkC and the low-affinity neurotrophin receptor p75 in spiral ganglion cell (SGC) of cisplatin-induced ototoxicity.</p><p><b>METHODS</b>The 50 adult Wistar rats were divided randomly into 5 groups received intraperitoneal injection of cisplatin with vary dose. Control group was received equivalent volumes of saline. The group received 1 day intraperitoneal injection was cisplatin treated at a dose of 5 mg/kg and killed at next day. The group received 3 days was cisplatin treated for 3 days at same dose daily and then killed at next day. The group A received 5 days was cisplatin treated for 5 days and killed at next day. The group B received 5 days was cisplatin treated for 5 days and then were sacrificed after 7 days. The change of mRNA level of neurotrophin receptors in cochlear tissue were examined by RT-PCR. The expressing pattern of TrkB, TrkC, P75 in damaged cochlea were study by immunochemistry using antibodies against TrkB, TrkC, P75 protein.</p><p><b>RESULTS</b>The research data showed the expression of Trk B, Trk C, p75 exhibited in SGC was dynamic along with the administration lasting. The mRNA and protein level of Trk B (x(-) +/- s) at day 1 and 3 after cisplatin treatment were 0.76 +/- 0.06, 88.78 +/- 4.28, 0.82 +/- 0.09 and 91.64 +/- 4.06, with significant difference among those and other groups (P < 0.05). The mRNA and protein level of TrkC at day 1 after cisplatin treatment were 0.80 +/- 0.06 and 89.66 +/- 2.76, with significant difference among that and other groups (P < 0.05). The mRNA and protein level of p75 at the control group and cisplatin treated groups were 0.64 +/- 0.04, 55.16 +/- 3.10, 0.77 +/- 0.04, 78.46 +/- 3.86, 1.01 +/- 0.09, 105.02 +/- 6.61, 1.18 +/- 0.09, 111.10 +/- 6.08, 0.51 +/- 0.04 and 42.74 +/- 5.20, with significant difference among the control group and cisplatin treated groups (P < 0.05).</p><p><b>CONCLUSIONS</b>The expression of Trk B increased to peak at day 1 - 3 after cisplatin treatment and decreased at day 5 early and following weeks. The expression of Trk C went up to peak at day 1 after cisplatin treatment and went down during subsequently time. P75 kept a trend of continuance increased during the drug treatment and decrease at drug stopped. The expression of Trk B, Trk C and P75 may be involved in cochlear insult with cisplatin-induced. Trk B and Trk C may play an important role in the reparative process of cochlear, especially at early stage of the damage. P75 could promote SGC apoptosis in cisplatin-induced neurotoxicity.</p>

Expression of P75NTR protein and RhoA mRNA in the brain of neonatal rats with white matter damage / 中国当代儿科杂志

<p><b>OBJECTIVE</b>Recent studies have indicated that the signal pathway of NgR-P75NTR- RhoA plays a key role in nerve injury and remodeling, but its exact mechanism and the role of the downstream molecule RhoA regulated by P75NTR remain unclear in hypoxia-ischemia (HI) neonatal animals. The present study was designed to assess the expression of P75NTR protein and RhoA mRNA in neonatal white matter and to investigate their relationship in newborn rats with white matter damage (WMD).</p><p><b>METHODS</b>The rat WMD model was established by the ligation of right common carotid artery, followed by 6% hypoxia exposure for 4 hrs. The control group was sham-operated, without HI treatment. The histological changes of brain tissue were observed under light and electron microscopes. Expression of P75NTR protein and RhoA mRNA in the brain white matter after 12, 24, 48 and 72 hrs and 7 days of HI were detected by RT-PCR and immunohistochemistry, respectively.</p><p><b>RESULTS</b>Periventricular white matter damage was observed by 48 hrs of HI. Expression of P75NTR protein increased in the striatum and callosum zones at 12 hrs, peaked at 48 hrs, and remained at a higher level than control until 72 hrs of HI in the WMD group (P < 0.01). After 7 days of HI expression of P75NTR protein was no longer statistically different from controls. The RhoA mRNA was higher in the WMD group for the first 72 hrs and then declined to control values.</p><p><b>CONCLUSIONS</b>Increased P75NTR protein might mediate apoptosis of nerve cells and inhibit the regeneration of neuron axons. The subsequent decline back to control value may be correlated with the aggregation of necrosis of nerve cells after HI. The patterns of RhoA mRNA expression were consistent with those of P75NTR protein, suggesting that the increased P75NTR level may promote RhoA mRNA expression.</p>