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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.
Subject(s)
Mice , Animals , Alzheimer Disease/pathology , Receptor, Nerve Growth Factor , Amyloid beta-Peptides , Autoantibodies , Mice, TransgenicABSTRACT
Recently p75 neurotrophin receptor (p75NTR) has been found to play a critical role in the pathology of neurodegen¬erative! diseases including Alzheimer's disease (AD) , Parkin¬son' s disease ( PI)), Huntington's disease ( HI)) , amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS).This arti¬cle reviews the research progress of p75NTR in regulating neuron apoptosis, axon degeneration and cognitive impairment, explo¬ring the application of p75NTR as a potential therapeutic target for the treatment of neurodegenerative diseases.
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Abstract Mesenchymal and epithelial stem cells were identified in dental tissues; however, knowledge about the odontogenic stem cells is limited, and there are some questions regarding their temporo-spatial dynamics in tooth development. Objective Our study aimed to analyze the expression of the stem cell markers CD146 and p75NTR during the different stages of odontogenesis. Methodology The groups consisted of 13.5, 15.5, 17.5 days old embryos, and 14 days postnatal BALB/c mice. The expression of CD146 and p75NTR was evaluated by immunohistochemistry. Results Our results showed that positive cells for both markers were present in all stages of tooth development, and the number of positive cells increased with the progression of this process. Cells of epithelial and ectomesenchymal origin were positive for CD146, and the expression of p75NTR was mainly detected in the dental papilla and dental follicle. In the postnatal group, dental pulp cells were positive for CD146, and the reduced enamel epithelium and the oral mucosa epithelium showed immunostaining for p75NTR. Conclusions These results suggest that the staining pattern of CD146 and p75NTR underwent temporal and spatial changes during odontogenesis and both markers were expressed by epithelial and mesenchymal cell types, which is relevant due to the significance of the epithelial-ectomesenchymal interactions in tooth development.
Subject(s)
Animals , Mice , Mesenchymal Stem Cells , Odontogenesis , Stem Cells , Cell Differentiation , Receptors, Nerve Growth Factor , CD146 Antigen , Mice, Inbred BALB CABSTRACT
Objective: To investigate the effect of small interfering RNA (siRNA) lentivirus-mediated silencing of P75 neurotrophin receptor (P75NTR) gene on osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) in rats. Methods: Three lentivirus-mediated P75NTR gene siRNA sequences (P75NTR-siRNA-1, 2, 3) and negative control (NC)-siRNA were designed and transfected into the 3rd generation Sprague Dawley (SD) rat BMSCs. The cells morphological changes were observed under an inverted microscope, and the expressions of P75NTR gene and protein in cells were detected by real-time fluorescence quantitative PCR and Western blot. Then the best silencing P75NTR-siRNA for subsequent osteogenic differentiation experiments was screened out. The 3rd generation SD rat BMSCs were randomly divided into experimental group, negative control group, and blank control group (normal BMSCs). The BMSCs of negative control group and experimental group were transfected with NC-siRNA and the selected P75NTR-siRNA lentiviral vector, respectively. The cells of each group were cultured by osteogenic induction. The expressions of osteogenic related proteins [osteocalcin (OCN) and Runx related transcription factor 2 (Runx2)] were detected by Western blot; the collagen type Ⅰ expression was observed by immunohistochemical staining; the osteogenesis of BMSCs was observed by alkaline phosphatase (ALP) detection and alizarin red staining. Results: After lentivirus-mediated P75NTR transfected into BMSCs, the expressions of P75NTR mRNA and protein significantly reduced ( P<0.05), and the best silencing P75NTR-siRNA was P75NTR-siRNA-3. After P75NTR gene was silenced, MTT test showed that the cell proliferation in the experimental group was significantly faster than those in the two control groups ( P<0.05). After osteogenic induction, the relative expressions of OCN and Runx2 proteins, collagen type Ⅰ expression, and ALP activity were significantly higher in the experimental group than in the two control groups, the differences were significant ( P<0.05). With the prolongation of osteogenic induction, the mineralized nodules in the experimental group gradually increased. Conclusion: Silencing the P75NTR gene with siRNA lentivirus can promote the osteogenic differentiation of rat BMSCs and provide a new idea for the treatment of bone defects.
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BACKGROUND: P75 neurotrophin receptor (P75NTR) is widely expressed in nerve tissues and cells, and plays a dual role in promoting or inhibiting differentiation. P75NTR is also overexpressed in local tissues with fracture nonunion. Therefore, P75NTR is studied for the osteogenic differentiation of bone marrow mesenchymal stem cells, which is of great significance to provide important targets for the clinical treatment of fracture nonunion. OBJECTIVE: To elucidate the effect of P75NTR overexpression on osteogenic differentiation of rat bone marrow mesenchymal stem cells in vitro. METHODS: The bilateral femurs of Sprague-Dawley rats were selected, and the rat bone marrow mesenchymal stem cells were extracted by whole bone marrow separation and adherence method and subcultured in vitro. The P75NTR overexpression plasmid GV358-P75NTR expressing enhanced green fluorescent protein was constructed, and the P75NTR overexpression lentiviral vector was collected by empty lentiviral vector packaging. Rat bone marrow mesenchymal stem cells primary cultured in vitro for 10 days were selected, and seeded into culture plates after digestion. P75NTR overexpression lentivirus and related infection reagents were added for subsequent infection experiments. After 7 days of infection, the expression of green fluorescent protein was observed by fluorescence microscope and overexpression of P75NTR protein was detected by western blot. Transfected cells were cultured for 7 days in a conventional medium, followed by culture in the osteogenic differentiation medium. Alkaline phosphatase activity was quantified by enzyme linked immunosorbent assay on the 7th, 10th, and 14th days after osteogenic induction. Formation of mineralized nodules was observed by alizarin red staining on the 7th and 14th days after osteogenic induction. RESULTS AND CONCLUSION: P75NTR overexpression lentiviral vector-infected bone marrow mesenchymal stem cells expressed green fluorescent protein (infection efficiency was about 90%), and the expression of P75NTR protein was significantly increased, which was significantly different from that in the negative control group (P < 0.05). Cell model of P75NTR overexpression was successfully constructed. Compared with the negative control and blank control groups, the alkaline phosphatase activity of the P75NTR overexpression group was significantly decreased at the corresponding time point after osteogenic induction, the number of mineralized nodules was significantly reduced, and cell aggregation and distribution were significantly weakened (P < 0.05). To conclude, P75NTR overexpression negatively regulates the osteogenic differentiation of rat bone marrow mesenchymal stem cells cultured in vitro. Overexpression of P75NTR in local tissues inhibits the osteogenic differentiation of surrounding bone marrow mesenchymal stem cells, which may be an important factor for bone defects or fracture nonunion.
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Objective To investigate serum p75 neurotrophin receptor-extracellular domain (p75NTR-ECD) level in patients with chronic cerebral hypoperfusion-vascular cognitive impairment (CCH-VCI) and its relationship with tumor necrosis factor α (TNF-α), interleukin (IL)-1β and IL-6. Methods The clinical data of patients with CCH-VCI (n＝34) were collected from Changhai Hospital, Naval Medical University (Second Military Medical University) from Aug. to Dec. 2018. Enzyme linked immunosorbent assay was applied for detection of serum levels of p75NTR-ECD, TNF-α, IL-1β and IL-6; and the results were then compared with those of ischemic stroke participants (n＝34) and healthy controls (n＝36), who were all in the same age range. Spearman correlation analysis was used to analyze the relationship between serum p75NTR-ECD level and the above-mentioned inflammatory factors in CCH-VCI patients. Results The serum p75NTR-ECD level in the CCH-VCI group was significantly higher than those in the healthy control group and the ischemic stroke group (544.36 [440.88, 628.50] pg/mL vs 276.49 [262.59, 313.87] pg/mL and 366.87 [337.09, 450.43] pg/mL, U＝87.500 and 335.500, both P0.05). The serum levels of TNF-α, IL-1β and IL-6 were 196.02 (141.20, 280.35) pg/mL, 68.23 (60.79, 91.94) pg/mL and 51.04 (40.24, 65.26) pg/mL in the CCH-VCI group, respectively, and 218.67 (143.76, 281.28) pg/mL, 76.87 (59.10, 99.91) pg/mL and 64.45 (43.13, 86.76) pg/mL in the ischemic stroke group, respectively, which were all significantly higher than those in the healthy control group (73.71 [56.94, 79.81] pg/mL, 42.98 [34.52, 51.34] pg/mL and 14.97 [11.76, 21.19] pg/mL, respectively; U＝ 31.000 and 4.000, 106.000 and 132.000, and 48.000 and 13.000; all P0.05). Serum p75NTR-ECD level in the CCH-VCI patients was correlated with TNF-α level (r＝0.391, P＝0.022), but not with IL-1β or IL-6 levels (r＝0.032 and 0.164, P＝ 0.855 and 0.355). Conclusion Serum p75NTR level may be related to inflammatory factors (TNF-α) after chronic cerebral hypoperfusion, and they may jointly participate in the pathogenesis of CCH-VCI.
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Alzheimer's disease (AD) is a neurodegenerative disease characterized by cognitive impairments with progressive loss of memory and behavioral disorder.Up to now,there is no effective therapy or drug to cure AD.Recent studies have shown p75 neurotrophin receptor (p75NTR) plays a critical role in the pathogenesis of AD,while the extracellular domain of p75 neurotrophin receptor (p75ECD) has neuroprotective effect and can attenuate the development and progression of AD.Therefore,p75ECD is a research-hotspot for prevention and treatment of AD.Here,recent studies are reviewed to learn about the advances of p75ECD in the prevention and therapy of AD and provide references for getting novel methods and drugs to treat AD.
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@#Objective To investigate the effect of Santong electroacupuncture (EA) on mRNA and protein expression of p75 neurotroph-in receptor (p75NTR) in rats with spinal cord injury (SCI). Methods A total of 72 female Sprague-Dawley rats were randomly assigned to sham operation group (group A, n=8) and model group (n=64). In the model group, Allen's method was used to make SCI rats model, in which 48 survived model rats were further subdivided into model control group (group B, n=12), EA group (group C, n=12), inhibitor Nogo extra cellular peptide residues 1-40 (NEP1-40) group (group D, n=12) and EA+inhibitor NEP1-40 group (group E, n=12) according to de-sign proposal. The treatment groups were electroacupunctured on Dazhui (GV14) and Yaoyangguan (GV3), bilateral Ciliao (BL32) and Zu-sanli (ST36) with loose-tight wave, for 20 minutes every day. After 7 and 14 days of treatment, injured spinal cord tissue was extracted for detecting. The mRNA and protein expression of p75NTR was detected by real-time fluorescent quantitative PCR, in situ hybridization and Western blotting respectively. The hind limb motor function was assessed with Basso-Beattie-Bresnahan (BBB) score. Results The BBB score increased in the treatment groups compared with group B, and was higher in group E than in groups C and D (P<0.05), as well as on the 14th day than on the 7th day in all the treatment groups (t>2.623, P<0.05). The mRNA and protein expression of p75NTR in spinal cord tissues decreased in the treatment groups compared with group B (P<0.05), and no significant difference was found among the treatment groups (P>0.05). Conclusion Santong elerctroacupuncture treatment could improve the hind limb motor function, which may associate with inhibition of the mRNA and protein expression of p75NTR in rats after SCI.
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@#Objective To explore the effect of Governor Vessel electroacupuncture in different time points on motor function and p75 neurotrophin receptor (p75NTR) after spinal cord injury. Methods A total of 180 adult male Sprague-Dawley rats were randomly divided into three groups (one day, three days and seven days after modeling), and each group was divided into normal control group, normal electroacupuncture group, sham operation group, model group and Governor Vessel electroacupuncture group with 12 cases in each group. The spinal cord injury model was established with the modified Allen's method. The normal electroacupuncture group and the Governor Vessel electroacupuncture group received electroacupuncture on Dazhui (DU14) and Mingmeng (DU04) acupoints. Basso-Beattic-Bresnahan (BBB) Scale was performed to assess the motor function of rats. The expression of p75NTR was detected with Western blotting. Results The BBB score of the model group and the Governor Vessel electroacupuncture group were significantly lower than that of the other three groups. The BBB score was significantly higher in the Governor Vessel electroacupuncture group than in the model group seven days after intervention (t=-4.510, P<0.001). The expression of p75NTR was siginificantly lower in the Governor Vessel electroacupuncture group than in the model group (P<0.01). Conclusion The expression of p75NTR increased after spinal cord injury. Governor Vessel electroacupuncture could improve the motor function, and inhibit the p75NTR expression of damaged spinal cord tissues.
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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.
Subject(s)
Animals , Male , Female , Dogs , Alcohol Abstinence , Alcoholism/metabolism , Brain-Derived Neurotrophic Factor/metabolism , Hippocampus/chemistry , Receptor, Nerve Growth Factor/metabolism , Receptor, trkB/metabolism , Brain-Derived Neurotrophic Factor/genetics , Chronic Disease , Disease Models, Animal , Gene Expression Regulation , Hippocampus/metabolism , Immunohistochemistry , Receptor, Nerve Growth Factor/genetics , Receptor, trkB/geneticsABSTRACT
@#Objective To observe the effects of electroacupuncture on learning and memory, and discuss the therapeutic mechanism. Methods 45 Sprague-Dawley rats were randomly divided into sham group (n=15), model group (n=15) and electroacupuncture group (n= 15). The latter 2 groups were modeled with middle cerebral artery occlusion for 1.5 h and reperfusion. The rats of electroacupuncture group received electroacupuncture at Shenting (DU24) and Baihui (DU20) for 7 days. Learning and memory ability was tested with Morris water maze. Neurologic impairment was assessed with Longa's score. Their hippocampus were observed under HE staining and the level of brain-derived neurotrophic factor (BDNF) and p75 neurotrophin receptor (p75NTR) protein were determined with Western blotting. Results Compared with the model group, the latency of water maze decreased and the times crossing the platform increased in electroacupuncture group (P<0.05), while the Longa's score significantly reduced (P<0.05), and the lesion of nerve cells were alleviated, with the decrease of p75NTR and increase of BDNF in the ischemic hippocampus (P<0.01). Conclusion Electroacupuncture can improve the learning and memory of cerebral ischemia-reperfusion rats, which may relate with up-regulating BDNF and down-regulating p75NTR in hippocampus.