Previous studies have shown that proliferation of endogenous neural precursor cells cannot alone compensate for the damage to neurons and axons. From the perspective of neural plastici- ty, we observed the effects of ...Previous studies have shown that proliferation of endogenous neural precursor cells cannot alone compensate for the damage to neurons and axons. From the perspective of neural plastici- ty, we observed the effects of functional electrical stimulation treatment on endogenous neural precursor cell proliferation and expression of basic fibroblast growth factor and epidermal growth factor in the rat brain on the infarct side. Functional electrical stimulation was performed in rat models of acute middle cerebral artery occlusion. Simultaneously, we set up a placebo stimulation group and a sham-operated group. Immunohistochemical staining showed that, at 7 and 14 days, compared with the placebo group, the numbers of nestin (a neural precursor cell marker)-positive cells in the subgranular zone and subventricular zone were increased in the functional electrical stimulation treatment group. Western blot assays and reverse-transcription PCR showed that total protein levels and gene expression of epidermal growth factor and basic fibroblast growth factor were also upregulated on the infarct side. Prehensile traction test results showed that, at 14 days, prehension function of rats in the functional electrical stimulation group was significantly better than in the placebo group. These results suggest that functional electrical stimulation can promote endogenous neural precursor cell proliferation in the brains of acute cerebral infarction rats, enhance expression of basic fibroblast growth factor and epidermal growth factor, and improve the motor function of rats.展开更多
Alzheimer's disease is closely associated with disorders of neurogenesis in the brain, and growing evidence supports the involvement of immunological mechanisms in the development of the disease. However, at present,...Alzheimer's disease is closely associated with disorders of neurogenesis in the brain, and growing evidence supports the involvement of immunological mechanisms in the development of the disease. However, at present, the role of T cells in neuronal regeneration in the brain is unknown. We injected amyloid-beta 1-42 peptide into the hippocampus of six BALB/c wild-type mice and six BALB/c-nude mice with T-cell immunodeficiency to establish an animal model of Alzhei- mer's disease. A further six mice of each genotype were injected with same volume of normal saline. Immunohistochemistry revealed that the number of regenerated neural progenitor cells in the hippocampus of BALB/c wild-type mice was significantly higher than that in BALB/c-nude mice. Quantitative fluorescence PCR assay showed that the expression levels of peripheral T cell-associated cytokines (interleukin-2, interferon-y) and hippocampal microglia-related cyto- kines (interleukin-113, tumor necrosis factor-a) correlated with the number of regenerated neural progenitor cells in the hippocampus. These results indicate that T cells promote hippocampal neurogenesis in Alzheimer's disease and T-cell immunodeficiency restricts neuronal regeneration in the hippocampus. The mechanism underlying the promotion of neuronal regeneration by T cells is mediated by an increased expression of peripheral T cells and central microglial cytokines in Alzheimer's disease mice. Our findings provide an experimental basis for understanding the role of T cells in Alzheimer's disease.展开更多
The pathological implication of amyloid precursor protein(APP)in Alzheimer’s disease has been widely documented due to its involvement in the generation of amyloid-β peptide.However,the physiological functions of AP...The pathological implication of amyloid precursor protein(APP)in Alzheimer’s disease has been widely documented due to its involvement in the generation of amyloid-β peptide.However,the physiological functions of APP are still poorly understood.APP is considered a multimodal protein due to its role in a wide variety of processes,both in the embryo and in the adult brain.Specifically,APP seems to play a key role in the proliferation,differentiation and maturation of neural stem cells.In addition,APP can be processed through two canonical processing pathways,generating different functionally active fragments:soluble APP-α,soluble APP-β,amyloid-β peptide and the APP intracellular C-terminal domain.These fragments also appear to modulate various functions in neural stem cells,including the processes of proliferation,neurogenesis,gliogenesis or cell death.However,the molecular mechanisms involved in these effects are still unclear.In this review,we summarize the physiological functions of APP and its main proteolytic derivatives in neural stem cells,as well as the possible signaling pathways that could be implicated in these effects.The knowledge of these functions and signaling pathways involved in the onset or during the development of Alzheimer’s disease is essential to advance the understanding of the pathogenesis of Alzheimer’s disease,and in the search for potential therapeutic targets.展开更多
BACKGROUND: Cerebral injury in adult mammals can induce neural precursor cells (NPCs) to proliferate and migrate towards the focal zone, but it is unclear whether endogenous NPCs can migrate towards regions distal ...BACKGROUND: Cerebral injury in adult mammals can induce neural precursor cells (NPCs) to proliferate and migrate towards the focal zone, but it is unclear whether endogenous NPCs can migrate towards regions distal to the hemorrhagic focus or whether NPCs differentiate in the peripheral hemorrhagic region. OBJECTIVE: To investigate the distribution of endogenous NPCs in different brain regions of rats with experimental cerebral hemorrhage, as well as NPC proliferation and differentiation with time. DESIGN, TIME AND SE'B'ING: A randomized, controlled animal experiment was performed at the Department of Neurobiology, Luzhou Medical College, between January 2007 and October 2008. MATERIALS: Bromodeoxyuridine (BrdU) was purchased from Roche, Germany. Mouse anti-rat BrdU monoclonal antibody, rabbit anti-nestin polyclonal antibody, rabbit anti-neuron specific enolase (NSE) polyclonal antibody were purchased from Wuhan Boster, China. Rabbit anti-glial fibrillary acidic protein (GFAP) polyclonal antibody was purchased from Sigma, USA. METHODS: Thirty-five adult Sprague Dawley rats were randomly divided into three groups: (1) cerebral hemorrhage group (n = 25), rats were stereotaxically administered 50 p L autologous arterial blood via the dorsal caudate putamen to induce cerebral hemorrhage; (2) sham-surgery group (n = 5), rats underwent surgery but did not receive blood injection; (3) blank control group (n = 5), rats received no surgery and blood administration. At 2 hours after surgery, all rats were intraperitoneally administered BrdU. MAIN OUTCOME MEASURES: Distribution and proliferation of BrdU-positive cells were observed by immunohistochemical staining. BrdU-positive cell differentiation into neurons and glial cells in the peripheral hemorrhagic region was detected by double-label immunofluorescence. RESULTS: Immunohistochemistry results revealed that BrdU-positive cells existed not only in the peripheral hemorrhagic region, such as the subependymal layer and hippocampal dentate gyrus, but also in the lateral septal nucleus, diagonal band, habenular nucleus, and cerebral cortex. Following cerebral hemorrhage, BrdU-positive cells in the peripheral hemorrhagic region gradually increased (P 〈 0.05), and peaked at 7 14 days. Double-label immunofluorescence showed that with time after cerebral hemorrhage, BrdU/nestin-positive cells decreased, but BrdU/GFAP- and BrdU/NSE-positive cells increased in the peripheral cerebral hemorrhagic region (P 〈 0.05). CONCLUSION: Cerebral hemorrhage can induce the proliferation of endogenous NPCs, which peaks at 1-2 weeks after hemorrhage. NPCs can also migrate towards the regions distal to the hemorrhagic focus, such as a diagonal band or lateral septal nucleus. NPCs can gradually differentiate with increasing time after hemorrhage.展开更多
BACKGROUND: Choosing proper donor cells is one of keys in experimental and clinical studies on cell replacement therapy (CRT) for treating Parkinson disease (PD). Embryonic mesencephalic precursor cells (MPCs) ...BACKGROUND: Choosing proper donor cells is one of keys in experimental and clinical studies on cell replacement therapy (CRT) for treating Parkinson disease (PD). Embryonic mesencephalic precursor cells (MPCs) can stably differentiate into dopaminergic neuron after in vitro proliferated culture. As compared with embryonic stem cell and neural stem cell strains, cell composition of embryonic MPCs after primary culture is also the most close to that of embryonic mesencephalic ventral cell suspension without proliferated culture. Successful experience accumulated in the latter suggests that primary cultured embryonic MPCs might be the most potential donor cells in clinical application with CRT for treating PD so far. OBJECTIVE: To investigate the feasibility of primary cultured embryonic precursor cells cultured primarily as donor cells in CRT for treating PD in rats. DESIGN : A randomized and controlled trial taking SD rats as experimental animals.SETTING: Department of Neurosurgery, Huashan Hospital Affiliated to Fudan University.MATERIALS: This experiment was carried out at the Institute of Neuroscience, Shanghai Institute for Biological Science, Chinese Academy of Sciences from July 2003 to June 2004. Totally 26 female SD rats, with body mass of 200 to 220 g, were provided by Shanghai Experimental Animal Center of Chinese Academy of Sciences. METHODS : Stereotaxic injection of 6-hydroxydopamine into the medial forebrain bundle were perfored to develop PD model rat. Among 26 SD rats, 20 rats achieved a more than 5 turns/min in apomorphine induced rotation test, reaching the standard of PD model rats. Immunohistochemical detection was performed on 1 out of 20 model rats after execution, and the other 19 rats were randomly divided into control group (n=5), sham transplantation group (n=5)and cell grafted group (n=9). Primary cultured E12 MPC cell suspension (1.2×10^11 L^-1)were used as donor cells. 4μL primary cultured E12 MPC cell suspension prepared freshly was injected into the lesioned corpus striatum of rats in cell grafted group, and 4μL D-Hank's solution was injected in sham transplantation group in the same way. There was no injection in control group. Apomorphine-induced rotation rate of PD rats were recorded respectively in cell grafted group and sham transplantation group pre-operation (initial value) and at postoperative 2, 4, 6 and 16 weeks. Apomorphine-induced rotation rate of PD rats was recorded in control group at postoperative 2 months (initial value) and following 2,4,6 and 16 weeks. To determine TH antigen with immunohistological ABC method (DAB developing) at 6 months post-transplantation to investigate the differentiation and survival of donor cells in the host body.MAIN OUTCOME MEASURES: Apomorphine-induced rotation behavior before and after transplantation and the survival and differentiation of implanted cells in the host body at 6 months post-transplantation. RESULTS: Among 19 model rats, one rat died after transplantation respectively in the cell grafted group and sham transplantation group; finally 17 model rats entered the stage of result analysis. Relative apomorphine-induced rotation rate was significantly decreased in the cell grafted group as compared with that before transplantation , with significant difference (P 〈 0.01 .P 〈 0.05);the mean value of relative apomorphine-induced rotation rate was significantly decreased at postoperative 16 weeks in cell grafted group as compared with that of corresponding relative rotation rate in control group , also with significant difference (P 〈 0.05).Immunohistological results showed that donor cells could differentiate into large and multi-polar dopaminergic neurons in the host body. CONCLUSION : Primary cultured embryonic MPCs can be used as the donor cells in CRT for treating PD.展开更多
We recently reported that targeted deletion of Pannexin 1 in neural precursor cells of the ventricular zone impairs the maintenance of these cells in healthy and stroke-injured brain. Here we frame this exciting new f...We recently reported that targeted deletion of Pannexin 1 in neural precursor cells of the ventricular zone impairs the maintenance of these cells in healthy and stroke-injured brain. Here we frame this exciting new finding in the context of our previous studies on Pannexin 1 in neural precursors as well as the close rela- tionship between Pannexin 1 and purinergic receptors established by other groups. Moreover, we identify important gaps in our understanding of Pannexin 1 in neural precursor cell biology in terms of the under- lying molecular mechanisms and functional/behavioural outcomes.展开更多
BACKGROUND The development of regenerative therapy for human spinal cord injury(SCI)is dramatically restricted by two main challenges:the need for a safe source of functionally active and reproducible neural stem cell...BACKGROUND The development of regenerative therapy for human spinal cord injury(SCI)is dramatically restricted by two main challenges:the need for a safe source of functionally active and reproducible neural stem cells and the need of adequate animal models for preclinical testing.Direct reprogramming of somatic cells into neuronal and glial precursors might be a promising solution to the first challenge.The use of non-human primates for preclinical studies exploring new treatment paradigms in SCI results in data with more translational relevance to human SCI.AIM To investigate the safety and efficacy of intraspinal transplantation of directly reprogrammed neural precursor cells(drNPCs).METHODS Seven non-human primates with verified complete thoracic SCI were divided into two groups:drNPC group(n=4)was subjected to intraspinal transplantation of 5 million drNPCs rostral and caudal to the lesion site 2 wk post injury,and lesion control(n=3)was injected identically with the equivalent volume of vehicle.RESULTS Follow-up for 12 wk revealed that animals in the drNPC group demonstrated a significant recovery of the paralyzed hindlimb as well as recovery of somatosensory evoked potential and motor evoked potential of injured pathways.Magnetic resonance diffusion tensor imaging data confirmed the intraspinal transplantation of drNPCs did not adversely affect the morphology of the central nervous system or cerebrospinal fluid circulation.Subsequent immunohistochemical analysis showed that drNPCs maintained SOX2 expression characteristic of multipotency in the transplanted spinal cord for at least 12 wk,migrating to areas of axon growth cones.CONCLUSION Our data demonstrated that drNPC transplantation was safe and contributed to improvement of spinal cord function after acute SCI,based on neurological status assessment and neurophysiological recovery within 12 wk after transplantation.The functional improvement described was not associated with neuronal differentiation of the allogeneic drNPCs.Instead,directed drNPCs migration to the areas of active growth cone formation may provide exosome and paracrine trophic support,thereby further supporting the regeneration processes.展开更多
Objective:To exploretheserum-freecultureconditionsfordifferentiatingmouseembryonicstemcells(ES cells)intoneuralprecursorcells(NPC)andcomparetheeffectsof humanembryonicfibroblasts(HEF)as thefeederlayer of ES withthatof...Objective:To exploretheserum-freecultureconditionsfordifferentiatingmouseembryonicstemcells(ES cells)intoneuralprecursorcells(NPC)andcomparetheeffectsof humanembryonicfibroblasts(HEF)as thefeederlayer of ES withthatof mouseembryonicfibroblasts(MEF)in vitro.Methods:MouseES cellswereculturedin or notin feederlayer cellsmediumcontainingor notleukemiainhibitoryfactorto suppresstheirdifferentiation.Immunocytochemicalmethod was usedto identifyNPCby detectingnestinantigenandalkalinephosphatase.Results: TheES cellsculturedin HEF werepositiveto alkalinephosphatase.Serum-freemediumallowedthedifferentiationof ES cellsintoNPC.Conclusion:HEFcouldreplaceMEFandkeeptheundifferentiatedconditionof ES cellswithmorebenefits.NPCof highpuritycould be culturedfromEScellsby serum-freeculturemethod.展开更多
There are few studies on the membrane protein Ankfyl. We have found Ankfyl is specifically expressed in neural stem/precursor cells during early development in mice (murine). To further explore Ankfyl function in ne...There are few studies on the membrane protein Ankfyl. We have found Ankfyl is specifically expressed in neural stem/precursor cells during early development in mice (murine). To further explore Ankfyl function in neural development, we developed a gene knockout mouse with a mixed Balb/C and C57/BL6 genetic background. Using immunofluorescence and in situ hybridization, neural defects were absent in mixed genetic Ankfyl null mice during development and in adults up to 2 months old. However, Ankfyl gene knockout mice with a pure genetic background were found to be lethal in the C57/BL6 inbred mice embryos, even after seven generations of backcrossing. Polymerase chain reaction confirmed homozygotes were unattainable as early as embryonic day 11.5. We conclude that Ankfyl protein is dispensable in neural stem/precursor ceils, but could be critical for early embryonic murine development, depending on the genetic background.展开更多
Artificial neural network (NN) is such a model as to imitate the structure and intelligence feature of human brain. It has strong nonlinear mapping function. To introduce NN into the study of earthquake prediction is ...Artificial neural network (NN) is such a model as to imitate the structure and intelligence feature of human brain. It has strong nonlinear mapping function. To introduce NN into the study of earthquake prediction is not only an extension of the application of artificial neural network model but also a new try for precursor observation to serve the earthquake prediction. In this paper, we analyzed the predictability of time series and gave a method of application of artificial neural network in forecasting earthquake precursor chaotic time series. Besides, taking the ground tilt observation of Jiangning and Xuzhou Station, the bulk strain observation of Liyang station as examples, we analyzed and forecasted their time series respectively. It is indicated that the precision of this method can meet the needs of practical task and therefore of great value in the application to the future practical earthquake analysis and prediction.展开更多
Objective To investigate whether buffalo rat liver cell conditioned medium (BRL CM) can be used as the culture medium of embryonic stem (ES) cells, and to get relatively pure neural precursor cells (NPCs) for treat...Objective To investigate whether buffalo rat liver cell conditioned medium (BRL CM) can be used as the culture medium of embryonic stem (ES) cells, and to get relatively pure neural precursor cells (NPCs) for treatment aim. Methods Mouse ES cells were cultured in BRL CM and medium contain leukemia inhibitory factor (LIF), respectively. NPCs were selectively cultured in serum free medium. Alkaline phosphatase activity was visualized with NBT/BCIP and nestin antigen was detected with immunocytochemical methods. Results BRL CM could be used as an efficiency culture condition instead of LIF in ES cells culture. About 86% of cells derived from ES cells in the serum free culture were NPCs. Conclusion BRL CM can replace LIF to use in ES cell culture. High purity of NPC can be induced from ES cells with serum free culture method.展开更多
Endogenous neural stem cells become "activated" after neuronal injury, but the activation sequence and fate of endogenous neural stem cells in focal cerebral ischemia model are little known. We evaluated the relatio...Endogenous neural stem cells become "activated" after neuronal injury, but the activation sequence and fate of endogenous neural stem cells in focal cerebral ischemia model are little known. We evaluated the relationships between neural stem cells and hypoxia-inducible factor-1α and vascular endothelial growth factor expression in a photothromobotic rat stroke model using immunohistochemistry and western blot analysis. We also evaluated the chronological changes of neural stem cells by 5-bromo-2′-deoxyuridine(BrdU) incorporation. Hypoxia-inducible factor-1α expression was initially increased from 1 hour after ischemic injury, followed by vascular endothelial growth factor expression. Hypoxia-inducible factor-1α immunoreactivity was detected in the ipsilateral cortical neurons of the infarct core and peri-infarct area. Vascular endothelial growth factor immunoreactivity was detected in bilateral cortex, but ipsilateral cortex staining intensity and numbers were greater than the contralateral cortex. Vascular endothelial growth factor immunoreactive cells were easily found along the peri-infarct area 12 hours after focal cerebral ischemia. The expression of nestin increased throughout the microvasculature in the ischemic core and the peri-infarct area in all experimental rats after 24 hours of ischemic injury. Nestin immunoreactivity increased in the subventricular zone during 12 hours to 3 days, and prominently increased in the ipsilateral cortex between 3–7 days. Nestin-labeled cells showed dual differentiation with microvessels near the infarct core and reactive astrocytes in the peri-infarct area. BrdU-labeled cells were increased gradually from day 1 in the ipsilateral subventricular zone and cortex, and numerous BrdU-labeled cells were observed in the peri-infarct area and non-lesioned cortex at 3 days. BrdU-labeled cells rather than neurons, were mainly co-labeled with nestin and GFAP. Early expressions of hypoxia-inducible factor-1α and vascular endothelial growth factor after ischemia made up the microenvironment to increase the neuronal plasticity of activated endogenous neural stem cells. Moreover, neural precursor cells after large-scale cortical injury could be recruited from the cortex nearby infarct core and subventricular zone.展开更多
Alzheimer's disease is pathologically defined by accumulation of extracellular amyloid-β(Aβ). Approximately 25 mutations in β-amyloid precursor protein(APP) are pathogenic and cause autosomal dominant Alzheimer...Alzheimer's disease is pathologically defined by accumulation of extracellular amyloid-β(Aβ). Approximately 25 mutations in β-amyloid precursor protein(APP) are pathogenic and cause autosomal dominant Alzheimer's disease. To date, the mechanism underlying the effect of APP mutation on Aβ generation is unclear. Therefore, investigating the mechanism of APP mutation on Alzheimer's disease may help understanding of disease pathogenesis. Thus, APP mutations(A673T, A673 V, E682 K, E693 G, and E693Q) were transiently co-transfected into human embryonic kidney cells. Western blot assay was used to detect expression levels of APP, beta-secretase 1, and presenilin 1 in cells. Enzyme-linked immunosorbent assay was performed to determine Aβ_(1–40) and Aβ_(1–42) levels. Liquid chromatography-tandem mass chromatography was used to examine VVIAT, FLF, ITL, VIV, IAT, VIT, TVI, and VVIA peptide levels. Immunofluorescence staining was performed to measure APP and early endosome antigen 1 immunoreactivity. Our results show that the protective A673 T mutation decreases Aβ_(42)/Aβ_(40) rate by downregulating IAT and upregulating VVIA levels. Pathogenic A673 V, E682 K, and E693 Q mutations promote Aβ_(42)/Aβ_(40) rate by increasing levels of CTF99, Aβ_(42), Aβ_(40), and IAT, and decreasing VVIA levels. Pathogenic E693 G mutation shows no significant change in Aβ_(42)/Aβ_(40) ratio because of inhibition of γ-secretase activity. APP mutations can change location from the cell surface to early endosomes. Our findings confirm that certain APP mutations accelerate Aβ generation by affecting the long Aβ cleavage pathway and increasing Aβ_(42/40) rate, thereby resulting in Alzheimer's disease.展开更多
Glycosides of Cistanche(GC)is a preparation used extensively for its neuroprotective effect against neurological diseases,but its mechanisms of action remains incompletely understood.Here,we established a bilateral ...Glycosides of Cistanche(GC)is a preparation used extensively for its neuroprotective effect against neurological diseases,but its mechanisms of action remains incompletely understood.Here,we established a bilateral common carotid artery occlusion model of vascular dementia in rats and injected the model rats with a suspension of GC(10 mg/kg/day,intraperitoneally)for 14 consecutive days.Immunohistochemistry showed that GC significantly reduced p-tau and amyloid beta(Aβ)immunoreactivity in the hippocampus of the model rats.Proteomic analysis demonstrated upregulation of mitochondrial precursor protein and downregulation of keratin type II cytoskeletal6A after GC treatment compared with model rats that had received saline.Western blot assay confirmed these findings.Our results suggest that the neuroprotective effect of GC in vascular dementia occurs via the promotion of neuronal cytoskeleton regeneration.展开更多
Curcumin exerts a neuroprotective effect on Alzheimer’s disease;however,it is not known whether microRNAs are involved in this protective effect.This study was conducted using swAPP695-HEK293 cells as an Alzheimer’s...Curcumin exerts a neuroprotective effect on Alzheimer’s disease;however,it is not known whether microRNAs are involved in this protective effect.This study was conducted using swAPP695-HEK293 cells as an Alzheimer’s disease cell model.swAPP695-HEK293 cells were treated with 0,0.5,1,2,5,and 10μM curcumin for 24 hours.The changes in miR-15b-5p,miR-19a-3p,miR-195-5p,miR-101-3p,miR-216b-5p,miR-16-5p and miR-185-5p expression were assessed by real-time quantitative polymerase chain reaction.The mRNA and protein levels of amyloid precursor protein,amyloid-β40 and amyloid-β42 were evaluated by quantitative real-time polymerase chain reaction,western blot assays and enzyme-linked immunosorbent assays.swAPP695-HEK293 cells were transfected with miR-15b-5p mimic,or treated with 1μM curcumin 24 hours before miR-15b-5p inhibitor transfection.The effects of curcumin on amyloid precursor protein,amyloid-β40 and amyloid-β42 levels were evaluated by western blot assays and enzyme-linked immunosorbent assay.Luciferase assays were used to analyze the interaction between miR-15b-5p and the 3′-untranslated region of amyloid precursor protein.The results show that amyloid precursor protein and amyloid-βexpression were enhanced in swAPP695-HEK293 cells compared with HEK293 parental cells.Curcumin suppressed the expression of amyloid precursor protein and amyloid-βand up-regulated the expression of miR-15b-5p in swAPP695-HEK293 cells.In addition,we found a negative association of miR-15b-5p expression with amyloid precursor protein and amyloid-βlevels in the curcumin-treated cells.Luciferase assays revealed that miR-15b-5p impaired the luciferase activity of the plasmid harboring the 3′-untranslated region of amyloid precursor protein.These findings indicate that curcumin down-regulates the expression of amyloid precursor protein and amyloid-βin swAPP695-HEK293 cells,which was partially mediated by miR-15b-5p via targeting of the 3′-untranslated region of amyloid precursor protein.展开更多
Previous studies have reported that non-human primates and rodents exposed to lead during brain development may become dependent on the deposition of pre-determined β-amyloid protein (Aβ),and exhibit upregulation ...Previous studies have reported that non-human primates and rodents exposed to lead during brain development may become dependent on the deposition of pre-determined β-amyloid protein (Aβ),and exhibit upregulation of β-site amyloid precursor protein expression in old age.However,further evidence is required to elucidate the precise relationship and molecular mechanisms underlying the effects of early lead exposure on excessive Aβ production in adult mammals.The present study investigated the effects of lead exposure on expression of β-amyloid precursor protein cleavage enzyme-1 (BACE-1) in the rat retina and the production of Aβ in early development,using the retina as a window for studying Alzheimer's disease.Adult rats were intraocularly injected with different doses of lead acetate (10μmol/L,100μmol/L,1 mmol/L,10 mmol/L and 100 mmol/L).The results revealed that retinal lead concentration,BACE-1 and its cleavage products β-C-terminal fragment and retina Aβ1-40 were all significantly increased in almost all of the lead exposure groups 48 hours later in a dose-dependent manner.The only exception was the 10μmol/L group.The distribution of BACE-1 in the retina did not exhibit obvious changes,and no distinctive increase in the activation of retinal microglia was apparent.Similarly,retinal synaptophysin expression did not exhibit any clear changes.These data suggest that lead exposure can result in the upregulation of retinal neuron BACE-1 expression in the early period of development and further increase the overproduction of Aβ1-40 in the retina.Our results provided novel insight into the molecular mechanisms underlying environmentally-induced Alzheimer's disease.展开更多
Although amyloid-β peptide is considered neurotoxic, it may mediate several physiological processes during embryonic development and in the adult brain. The pathological function of amyloid-β peptide has been extens...Although amyloid-β peptide is considered neurotoxic, it may mediate several physiological processes during embryonic development and in the adult brain. The pathological function of amyloid-β peptide has been extensively studied due to its implication in Alzheimer’s disease, but its physiological function remains poorly understood. Amyloid-β peptide can be detected in non-aggregated (monomeric) and aggregated (oligomeric and fibrillary) forms. Each form has different cytotoxic and/or physiological properties, so amyloid-β peptide and its role in Alzheimer’s disease need to be studied further. Neural stem cells and neural precursor cells are good tools for the study on neurodegenerative diseases and can provide future therapeutic applications in diseases such as Alzheimer’s disease. In this review, we provide an outline of the effects of amyloid-β peptide, in monomeric and aggregated forms, on the biology of neural stem cells/neural precursor cells, and discuss the controversies. We also describe the possible molecular targets that could be implicated in these effects, especially GSK3β. A better understanding of amyloid-β peptide (both physiological and pathological), and the signaling pathways involved are essential to advance the field of Alzheimer’s disease.展开更多
After gene mutation, the pcDNA3.1/APP595/596 plasmid was transfected into HEK293 cells to establish a cell model of Alzheimer's disease. The cell model was treated with donepezil or compound Danshen tablets after cul...After gene mutation, the pcDNA3.1/APP595/596 plasmid was transfected into HEK293 cells to establish a cell model of Alzheimer's disease. The cell model was treated with donepezil or compound Danshen tablets after culture for 72 hours. Reverse transcription-PCR showed that the mRNA expression of amyloid protein precursor decreased in all groups following culture for 24 hours, and that there was no significant difference in the amount of decrease between donepezil and compound Danshen tablets. Our results suggest that compound Danshen tablets can reduce expression of the mRNA for amyloid protein precursor in a transgenic cell model of Alzheimer's disease, with similar effects to donepezil.展开更多
基金the National Natural Science Foundation of China,grants No.30772304,30973166,and 81171863
文摘Previous studies have shown that proliferation of endogenous neural precursor cells cannot alone compensate for the damage to neurons and axons. From the perspective of neural plastici- ty, we observed the effects of functional electrical stimulation treatment on endogenous neural precursor cell proliferation and expression of basic fibroblast growth factor and epidermal growth factor in the rat brain on the infarct side. Functional electrical stimulation was performed in rat models of acute middle cerebral artery occlusion. Simultaneously, we set up a placebo stimulation group and a sham-operated group. Immunohistochemical staining showed that, at 7 and 14 days, compared with the placebo group, the numbers of nestin (a neural precursor cell marker)-positive cells in the subgranular zone and subventricular zone were increased in the functional electrical stimulation treatment group. Western blot assays and reverse-transcription PCR showed that total protein levels and gene expression of epidermal growth factor and basic fibroblast growth factor were also upregulated on the infarct side. Prehensile traction test results showed that, at 14 days, prehension function of rats in the functional electrical stimulation group was significantly better than in the placebo group. These results suggest that functional electrical stimulation can promote endogenous neural precursor cell proliferation in the brains of acute cerebral infarction rats, enhance expression of basic fibroblast growth factor and epidermal growth factor, and improve the motor function of rats.
基金supported by the National Natural Science Foundation of China,No.30840073the Medical Science Foundation of Guangdong Province,No.A2012298
文摘Alzheimer's disease is closely associated with disorders of neurogenesis in the brain, and growing evidence supports the involvement of immunological mechanisms in the development of the disease. However, at present, the role of T cells in neuronal regeneration in the brain is unknown. We injected amyloid-beta 1-42 peptide into the hippocampus of six BALB/c wild-type mice and six BALB/c-nude mice with T-cell immunodeficiency to establish an animal model of Alzhei- mer's disease. A further six mice of each genotype were injected with same volume of normal saline. Immunohistochemistry revealed that the number of regenerated neural progenitor cells in the hippocampus of BALB/c wild-type mice was significantly higher than that in BALB/c-nude mice. Quantitative fluorescence PCR assay showed that the expression levels of peripheral T cell-associated cytokines (interleukin-2, interferon-y) and hippocampal microglia-related cyto- kines (interleukin-113, tumor necrosis factor-a) correlated with the number of regenerated neural progenitor cells in the hippocampus. These results indicate that T cells promote hippocampal neurogenesis in Alzheimer's disease and T-cell immunodeficiency restricts neuronal regeneration in the hippocampus. The mechanism underlying the promotion of neuronal regeneration by T cells is mediated by an increased expression of peripheral T cells and central microglial cytokines in Alzheimer's disease mice. Our findings provide an experimental basis for understanding the role of T cells in Alzheimer's disease.
基金supported by grants from the Ministerio de Ciencia e Innovación-Instituto de Salud Carlos Ⅲ(PI-10/00291 and MPY1412/09)Ministerio de Economía y Competitividad(SAF2015-71140-R)+2 种基金Comunidad de Madrid(Neurostem-Comunidad de Madrid consortium S2010/BMD-2336)supported by grants from Plan de Empleo Juvenil-Ministerio de Economía y Competitividad
文摘The pathological implication of amyloid precursor protein(APP)in Alzheimer’s disease has been widely documented due to its involvement in the generation of amyloid-β peptide.However,the physiological functions of APP are still poorly understood.APP is considered a multimodal protein due to its role in a wide variety of processes,both in the embryo and in the adult brain.Specifically,APP seems to play a key role in the proliferation,differentiation and maturation of neural stem cells.In addition,APP can be processed through two canonical processing pathways,generating different functionally active fragments:soluble APP-α,soluble APP-β,amyloid-β peptide and the APP intracellular C-terminal domain.These fragments also appear to modulate various functions in neural stem cells,including the processes of proliferation,neurogenesis,gliogenesis or cell death.However,the molecular mechanisms involved in these effects are still unclear.In this review,we summarize the physiological functions of APP and its main proteolytic derivatives in neural stem cells,as well as the possible signaling pathways that could be implicated in these effects.The knowledge of these functions and signaling pathways involved in the onset or during the development of Alzheimer’s disease is essential to advance the understanding of the pathogenesis of Alzheimer’s disease,and in the search for potential therapeutic targets.
文摘BACKGROUND: Cerebral injury in adult mammals can induce neural precursor cells (NPCs) to proliferate and migrate towards the focal zone, but it is unclear whether endogenous NPCs can migrate towards regions distal to the hemorrhagic focus or whether NPCs differentiate in the peripheral hemorrhagic region. OBJECTIVE: To investigate the distribution of endogenous NPCs in different brain regions of rats with experimental cerebral hemorrhage, as well as NPC proliferation and differentiation with time. DESIGN, TIME AND SE'B'ING: A randomized, controlled animal experiment was performed at the Department of Neurobiology, Luzhou Medical College, between January 2007 and October 2008. MATERIALS: Bromodeoxyuridine (BrdU) was purchased from Roche, Germany. Mouse anti-rat BrdU monoclonal antibody, rabbit anti-nestin polyclonal antibody, rabbit anti-neuron specific enolase (NSE) polyclonal antibody were purchased from Wuhan Boster, China. Rabbit anti-glial fibrillary acidic protein (GFAP) polyclonal antibody was purchased from Sigma, USA. METHODS: Thirty-five adult Sprague Dawley rats were randomly divided into three groups: (1) cerebral hemorrhage group (n = 25), rats were stereotaxically administered 50 p L autologous arterial blood via the dorsal caudate putamen to induce cerebral hemorrhage; (2) sham-surgery group (n = 5), rats underwent surgery but did not receive blood injection; (3) blank control group (n = 5), rats received no surgery and blood administration. At 2 hours after surgery, all rats were intraperitoneally administered BrdU. MAIN OUTCOME MEASURES: Distribution and proliferation of BrdU-positive cells were observed by immunohistochemical staining. BrdU-positive cell differentiation into neurons and glial cells in the peripheral hemorrhagic region was detected by double-label immunofluorescence. RESULTS: Immunohistochemistry results revealed that BrdU-positive cells existed not only in the peripheral hemorrhagic region, such as the subependymal layer and hippocampal dentate gyrus, but also in the lateral septal nucleus, diagonal band, habenular nucleus, and cerebral cortex. Following cerebral hemorrhage, BrdU-positive cells in the peripheral hemorrhagic region gradually increased (P 〈 0.05), and peaked at 7 14 days. Double-label immunofluorescence showed that with time after cerebral hemorrhage, BrdU/nestin-positive cells decreased, but BrdU/GFAP- and BrdU/NSE-positive cells increased in the peripheral cerebral hemorrhagic region (P 〈 0.05). CONCLUSION: Cerebral hemorrhage can induce the proliferation of endogenous NPCs, which peaks at 1-2 weeks after hemorrhage. NPCs can also migrate towards the regions distal to the hemorrhagic focus, such as a diagonal band or lateral septal nucleus. NPCs can gradually differentiate with increasing time after hemorrhage.
文摘BACKGROUND: Choosing proper donor cells is one of keys in experimental and clinical studies on cell replacement therapy (CRT) for treating Parkinson disease (PD). Embryonic mesencephalic precursor cells (MPCs) can stably differentiate into dopaminergic neuron after in vitro proliferated culture. As compared with embryonic stem cell and neural stem cell strains, cell composition of embryonic MPCs after primary culture is also the most close to that of embryonic mesencephalic ventral cell suspension without proliferated culture. Successful experience accumulated in the latter suggests that primary cultured embryonic MPCs might be the most potential donor cells in clinical application with CRT for treating PD so far. OBJECTIVE: To investigate the feasibility of primary cultured embryonic precursor cells cultured primarily as donor cells in CRT for treating PD in rats. DESIGN : A randomized and controlled trial taking SD rats as experimental animals.SETTING: Department of Neurosurgery, Huashan Hospital Affiliated to Fudan University.MATERIALS: This experiment was carried out at the Institute of Neuroscience, Shanghai Institute for Biological Science, Chinese Academy of Sciences from July 2003 to June 2004. Totally 26 female SD rats, with body mass of 200 to 220 g, were provided by Shanghai Experimental Animal Center of Chinese Academy of Sciences. METHODS : Stereotaxic injection of 6-hydroxydopamine into the medial forebrain bundle were perfored to develop PD model rat. Among 26 SD rats, 20 rats achieved a more than 5 turns/min in apomorphine induced rotation test, reaching the standard of PD model rats. Immunohistochemical detection was performed on 1 out of 20 model rats after execution, and the other 19 rats were randomly divided into control group (n=5), sham transplantation group (n=5)and cell grafted group (n=9). Primary cultured E12 MPC cell suspension (1.2×10^11 L^-1)were used as donor cells. 4μL primary cultured E12 MPC cell suspension prepared freshly was injected into the lesioned corpus striatum of rats in cell grafted group, and 4μL D-Hank's solution was injected in sham transplantation group in the same way. There was no injection in control group. Apomorphine-induced rotation rate of PD rats were recorded respectively in cell grafted group and sham transplantation group pre-operation (initial value) and at postoperative 2, 4, 6 and 16 weeks. Apomorphine-induced rotation rate of PD rats was recorded in control group at postoperative 2 months (initial value) and following 2,4,6 and 16 weeks. To determine TH antigen with immunohistological ABC method (DAB developing) at 6 months post-transplantation to investigate the differentiation and survival of donor cells in the host body.MAIN OUTCOME MEASURES: Apomorphine-induced rotation behavior before and after transplantation and the survival and differentiation of implanted cells in the host body at 6 months post-transplantation. RESULTS: Among 19 model rats, one rat died after transplantation respectively in the cell grafted group and sham transplantation group; finally 17 model rats entered the stage of result analysis. Relative apomorphine-induced rotation rate was significantly decreased in the cell grafted group as compared with that before transplantation , with significant difference (P 〈 0.01 .P 〈 0.05);the mean value of relative apomorphine-induced rotation rate was significantly decreased at postoperative 16 weeks in cell grafted group as compared with that of corresponding relative rotation rate in control group , also with significant difference (P 〈 0.05).Immunohistological results showed that donor cells could differentiate into large and multi-polar dopaminergic neurons in the host body. CONCLUSION : Primary cultured embryonic MPCs can be used as the donor cells in CRT for treating PD.
基金Research in the Swayne lab was supported by operating grants to LAS from the Natural Sciences and Engineering Research Council of Canada(NSERC Discovery Grant)the Canadian Institutes of Health Research(CIHR Grant MOP142215)+5 种基金The Scottish Rite Charitable Foundation of Canada and the University of Victoria Division of Medical Sciencesby infrastructure grants from the Canadian Foundation for Innovation(CFI)the British Columbia Knowledge Development Fund(BCKDF)supported by a Michael Smith Foundation for Health Research and British Columbia Schizophrenia Society Foundation Scholar Awardsupported by a University of Victoria Fellowship Graduate Awardsupported by a Vanier Canada Graduate Scholarship(NSERC)
文摘We recently reported that targeted deletion of Pannexin 1 in neural precursor cells of the ventricular zone impairs the maintenance of these cells in healthy and stroke-injured brain. Here we frame this exciting new finding in the context of our previous studies on Pannexin 1 in neural precursors as well as the close rela- tionship between Pannexin 1 and purinergic receptors established by other groups. Moreover, we identify important gaps in our understanding of Pannexin 1 in neural precursor cell biology in terms of the under- lying molecular mechanisms and functional/behavioural outcomes.
基金Supported by Russian Science Foundation,No.16-15-10432。
文摘BACKGROUND The development of regenerative therapy for human spinal cord injury(SCI)is dramatically restricted by two main challenges:the need for a safe source of functionally active and reproducible neural stem cells and the need of adequate animal models for preclinical testing.Direct reprogramming of somatic cells into neuronal and glial precursors might be a promising solution to the first challenge.The use of non-human primates for preclinical studies exploring new treatment paradigms in SCI results in data with more translational relevance to human SCI.AIM To investigate the safety and efficacy of intraspinal transplantation of directly reprogrammed neural precursor cells(drNPCs).METHODS Seven non-human primates with verified complete thoracic SCI were divided into two groups:drNPC group(n=4)was subjected to intraspinal transplantation of 5 million drNPCs rostral and caudal to the lesion site 2 wk post injury,and lesion control(n=3)was injected identically with the equivalent volume of vehicle.RESULTS Follow-up for 12 wk revealed that animals in the drNPC group demonstrated a significant recovery of the paralyzed hindlimb as well as recovery of somatosensory evoked potential and motor evoked potential of injured pathways.Magnetic resonance diffusion tensor imaging data confirmed the intraspinal transplantation of drNPCs did not adversely affect the morphology of the central nervous system or cerebrospinal fluid circulation.Subsequent immunohistochemical analysis showed that drNPCs maintained SOX2 expression characteristic of multipotency in the transplanted spinal cord for at least 12 wk,migrating to areas of axon growth cones.CONCLUSION Our data demonstrated that drNPC transplantation was safe and contributed to improvement of spinal cord function after acute SCI,based on neurological status assessment and neurophysiological recovery within 12 wk after transplantation.The functional improvement described was not associated with neuronal differentiation of the allogeneic drNPCs.Instead,directed drNPCs migration to the areas of active growth cone formation may provide exosome and paracrine trophic support,thereby further supporting the regeneration processes.
文摘Objective:To exploretheserum-freecultureconditionsfordifferentiatingmouseembryonicstemcells(ES cells)intoneuralprecursorcells(NPC)andcomparetheeffectsof humanembryonicfibroblasts(HEF)as thefeederlayer of ES withthatof mouseembryonicfibroblasts(MEF)in vitro.Methods:MouseES cellswereculturedin or notin feederlayer cellsmediumcontainingor notleukemiainhibitoryfactorto suppresstheirdifferentiation.Immunocytochemicalmethod was usedto identifyNPCby detectingnestinantigenandalkalinephosphatase.Results: TheES cellsculturedin HEF werepositiveto alkalinephosphatase.Serum-freemediumallowedthedifferentiationof ES cellsintoNPC.Conclusion:HEFcouldreplaceMEFandkeeptheundifferentiatedconditionof ES cellswithmorebenefits.NPCof highpuritycould be culturedfromEScellsby serum-freeculturemethod.
基金Dr.Hui Fu was supported by the National Natural Science Foundation of China,No.81371338by Open Research Fund Program of Hubei-MOST KLOS & KLOBMEDr.Zu-neng Lu was supported by grants from Health and Family Planning Commission of Hubei Province scientific research project,No.WJ2015MA007
文摘There are few studies on the membrane protein Ankfyl. We have found Ankfyl is specifically expressed in neural stem/precursor cells during early development in mice (murine). To further explore Ankfyl function in neural development, we developed a gene knockout mouse with a mixed Balb/C and C57/BL6 genetic background. Using immunofluorescence and in situ hybridization, neural defects were absent in mixed genetic Ankfyl null mice during development and in adults up to 2 months old. However, Ankfyl gene knockout mice with a pure genetic background were found to be lethal in the C57/BL6 inbred mice embryos, even after seven generations of backcrossing. Polymerase chain reaction confirmed homozygotes were unattainable as early as embryonic day 11.5. We conclude that Ankfyl protein is dispensable in neural stem/precursor ceils, but could be critical for early embryonic murine development, depending on the genetic background.
文摘Artificial neural network (NN) is such a model as to imitate the structure and intelligence feature of human brain. It has strong nonlinear mapping function. To introduce NN into the study of earthquake prediction is not only an extension of the application of artificial neural network model but also a new try for precursor observation to serve the earthquake prediction. In this paper, we analyzed the predictability of time series and gave a method of application of artificial neural network in forecasting earthquake precursor chaotic time series. Besides, taking the ground tilt observation of Jiangning and Xuzhou Station, the bulk strain observation of Liyang station as examples, we analyzed and forecasted their time series respectively. It is indicated that the precision of this method can meet the needs of practical task and therefore of great value in the application to the future practical earthquake analysis and prediction.
文摘Objective To investigate whether buffalo rat liver cell conditioned medium (BRL CM) can be used as the culture medium of embryonic stem (ES) cells, and to get relatively pure neural precursor cells (NPCs) for treatment aim. Methods Mouse ES cells were cultured in BRL CM and medium contain leukemia inhibitory factor (LIF), respectively. NPCs were selectively cultured in serum free medium. Alkaline phosphatase activity was visualized with NBT/BCIP and nestin antigen was detected with immunocytochemical methods. Results BRL CM could be used as an efficiency culture condition instead of LIF in ES cells culture. About 86% of cells derived from ES cells in the serum free culture were NPCs. Conclusion BRL CM can replace LIF to use in ES cell culture. High purity of NPC can be induced from ES cells with serum free culture method.
基金supported by the National Research Foundation of Korea Grant funded by the Korean Government,No.NRF-013-2011-1-E00045
文摘Endogenous neural stem cells become "activated" after neuronal injury, but the activation sequence and fate of endogenous neural stem cells in focal cerebral ischemia model are little known. We evaluated the relationships between neural stem cells and hypoxia-inducible factor-1α and vascular endothelial growth factor expression in a photothromobotic rat stroke model using immunohistochemistry and western blot analysis. We also evaluated the chronological changes of neural stem cells by 5-bromo-2′-deoxyuridine(BrdU) incorporation. Hypoxia-inducible factor-1α expression was initially increased from 1 hour after ischemic injury, followed by vascular endothelial growth factor expression. Hypoxia-inducible factor-1α immunoreactivity was detected in the ipsilateral cortical neurons of the infarct core and peri-infarct area. Vascular endothelial growth factor immunoreactivity was detected in bilateral cortex, but ipsilateral cortex staining intensity and numbers were greater than the contralateral cortex. Vascular endothelial growth factor immunoreactive cells were easily found along the peri-infarct area 12 hours after focal cerebral ischemia. The expression of nestin increased throughout the microvasculature in the ischemic core and the peri-infarct area in all experimental rats after 24 hours of ischemic injury. Nestin immunoreactivity increased in the subventricular zone during 12 hours to 3 days, and prominently increased in the ipsilateral cortex between 3–7 days. Nestin-labeled cells showed dual differentiation with microvessels near the infarct core and reactive astrocytes in the peri-infarct area. BrdU-labeled cells were increased gradually from day 1 in the ipsilateral subventricular zone and cortex, and numerous BrdU-labeled cells were observed in the peri-infarct area and non-lesioned cortex at 3 days. BrdU-labeled cells rather than neurons, were mainly co-labeled with nestin and GFAP. Early expressions of hypoxia-inducible factor-1α and vascular endothelial growth factor after ischemia made up the microenvironment to increase the neuronal plasticity of activated endogenous neural stem cells. Moreover, neural precursor cells after large-scale cortical injury could be recruited from the cortex nearby infarct core and subventricular zone.
基金funded by the National Natural Science Foundation of China,No.81671268(to HQ)partially supported by a grant from the Ministry of Science and Technology of China,No.2013YQ03059514(to HQ)a grant from Key Laboratory for Neurodegenerative Disease of Ministry of Education of China,No.2015SJBX05(to HQ),2015SJZS01(to HQ)
文摘Alzheimer's disease is pathologically defined by accumulation of extracellular amyloid-β(Aβ). Approximately 25 mutations in β-amyloid precursor protein(APP) are pathogenic and cause autosomal dominant Alzheimer's disease. To date, the mechanism underlying the effect of APP mutation on Aβ generation is unclear. Therefore, investigating the mechanism of APP mutation on Alzheimer's disease may help understanding of disease pathogenesis. Thus, APP mutations(A673T, A673 V, E682 K, E693 G, and E693Q) were transiently co-transfected into human embryonic kidney cells. Western blot assay was used to detect expression levels of APP, beta-secretase 1, and presenilin 1 in cells. Enzyme-linked immunosorbent assay was performed to determine Aβ_(1–40) and Aβ_(1–42) levels. Liquid chromatography-tandem mass chromatography was used to examine VVIAT, FLF, ITL, VIV, IAT, VIT, TVI, and VVIA peptide levels. Immunofluorescence staining was performed to measure APP and early endosome antigen 1 immunoreactivity. Our results show that the protective A673 T mutation decreases Aβ_(42)/Aβ_(40) rate by downregulating IAT and upregulating VVIA levels. Pathogenic A673 V, E682 K, and E693 Q mutations promote Aβ_(42)/Aβ_(40) rate by increasing levels of CTF99, Aβ_(42), Aβ_(40), and IAT, and decreasing VVIA levels. Pathogenic E693 G mutation shows no significant change in Aβ_(42)/Aβ_(40) ratio because of inhibition of γ-secretase activity. APP mutations can change location from the cell surface to early endosomes. Our findings confirm that certain APP mutations accelerate Aβ generation by affecting the long Aβ cleavage pathway and increasing Aβ_(42/40) rate, thereby resulting in Alzheimer's disease.
基金supported by the National Natural Science Foundation of China,No.30960520the Natural Science Foundation of Inner Mongolia Autonomous Region of China,No.2016MS0837
文摘Glycosides of Cistanche(GC)is a preparation used extensively for its neuroprotective effect against neurological diseases,but its mechanisms of action remains incompletely understood.Here,we established a bilateral common carotid artery occlusion model of vascular dementia in rats and injected the model rats with a suspension of GC(10 mg/kg/day,intraperitoneally)for 14 consecutive days.Immunohistochemistry showed that GC significantly reduced p-tau and amyloid beta(Aβ)immunoreactivity in the hippocampus of the model rats.Proteomic analysis demonstrated upregulation of mitochondrial precursor protein and downregulation of keratin type II cytoskeletal6A after GC treatment compared with model rats that had received saline.Western blot assay confirmed these findings.Our results suggest that the neuroprotective effect of GC in vascular dementia occurs via the promotion of neuronal cytoskeleton regeneration.
基金supported by the Science and Technology Planning Project of Guangdong Province of China,No.2016A020226022(to HYL)the Medical and Health Technology Project of Guangzhou of China,No.20161A011068(to HYL)the Guangzhou Science Technology and Innovation Commission of China,No.201704020043(to QCG)
文摘Curcumin exerts a neuroprotective effect on Alzheimer’s disease;however,it is not known whether microRNAs are involved in this protective effect.This study was conducted using swAPP695-HEK293 cells as an Alzheimer’s disease cell model.swAPP695-HEK293 cells were treated with 0,0.5,1,2,5,and 10μM curcumin for 24 hours.The changes in miR-15b-5p,miR-19a-3p,miR-195-5p,miR-101-3p,miR-216b-5p,miR-16-5p and miR-185-5p expression were assessed by real-time quantitative polymerase chain reaction.The mRNA and protein levels of amyloid precursor protein,amyloid-β40 and amyloid-β42 were evaluated by quantitative real-time polymerase chain reaction,western blot assays and enzyme-linked immunosorbent assays.swAPP695-HEK293 cells were transfected with miR-15b-5p mimic,or treated with 1μM curcumin 24 hours before miR-15b-5p inhibitor transfection.The effects of curcumin on amyloid precursor protein,amyloid-β40 and amyloid-β42 levels were evaluated by western blot assays and enzyme-linked immunosorbent assay.Luciferase assays were used to analyze the interaction between miR-15b-5p and the 3′-untranslated region of amyloid precursor protein.The results show that amyloid precursor protein and amyloid-βexpression were enhanced in swAPP695-HEK293 cells compared with HEK293 parental cells.Curcumin suppressed the expression of amyloid precursor protein and amyloid-βand up-regulated the expression of miR-15b-5p in swAPP695-HEK293 cells.In addition,we found a negative association of miR-15b-5p expression with amyloid precursor protein and amyloid-βlevels in the curcumin-treated cells.Luciferase assays revealed that miR-15b-5p impaired the luciferase activity of the plasmid harboring the 3′-untranslated region of amyloid precursor protein.These findings indicate that curcumin down-regulates the expression of amyloid precursor protein and amyloid-βin swAPP695-HEK293 cells,which was partially mediated by miR-15b-5p via targeting of the 3′-untranslated region of amyloid precursor protein.
基金the National Natural Science Foundation of China,No.30900773the National University Basic Research Foundation of China,No.2010QZZD022
文摘Previous studies have reported that non-human primates and rodents exposed to lead during brain development may become dependent on the deposition of pre-determined β-amyloid protein (Aβ),and exhibit upregulation of β-site amyloid precursor protein expression in old age.However,further evidence is required to elucidate the precise relationship and molecular mechanisms underlying the effects of early lead exposure on excessive Aβ production in adult mammals.The present study investigated the effects of lead exposure on expression of β-amyloid precursor protein cleavage enzyme-1 (BACE-1) in the rat retina and the production of Aβ in early development,using the retina as a window for studying Alzheimer's disease.Adult rats were intraocularly injected with different doses of lead acetate (10μmol/L,100μmol/L,1 mmol/L,10 mmol/L and 100 mmol/L).The results revealed that retinal lead concentration,BACE-1 and its cleavage products β-C-terminal fragment and retina Aβ1-40 were all significantly increased in almost all of the lead exposure groups 48 hours later in a dose-dependent manner.The only exception was the 10μmol/L group.The distribution of BACE-1 in the retina did not exhibit obvious changes,and no distinctive increase in the activation of retinal microglia was apparent.Similarly,retinal synaptophysin expression did not exhibit any clear changes.These data suggest that lead exposure can result in the upregulation of retinal neuron BACE-1 expression in the early period of development and further increase the overproduction of Aβ1-40 in the retina.Our results provided novel insight into the molecular mechanisms underlying environmentally-induced Alzheimer's disease.
基金supported by grants from the MICINN-ISCⅢ(PI-10/00291 and MPY1412/09)MINECO(SAF2015-71140-R)+1 种基金Comunidad de Madrid(NEUROSTEMCM consortium S2010/BMD-2336)(all to IL)
文摘Although amyloid-β peptide is considered neurotoxic, it may mediate several physiological processes during embryonic development and in the adult brain. The pathological function of amyloid-β peptide has been extensively studied due to its implication in Alzheimer’s disease, but its physiological function remains poorly understood. Amyloid-β peptide can be detected in non-aggregated (monomeric) and aggregated (oligomeric and fibrillary) forms. Each form has different cytotoxic and/or physiological properties, so amyloid-β peptide and its role in Alzheimer’s disease need to be studied further. Neural stem cells and neural precursor cells are good tools for the study on neurodegenerative diseases and can provide future therapeutic applications in diseases such as Alzheimer’s disease. In this review, we provide an outline of the effects of amyloid-β peptide, in monomeric and aggregated forms, on the biology of neural stem cells/neural precursor cells, and discuss the controversies. We also describe the possible molecular targets that could be implicated in these effects, especially GSK3β. A better understanding of amyloid-β peptide (both physiological and pathological), and the signaling pathways involved are essential to advance the field of Alzheimer’s disease.
基金supported by the Bureau of Traditional Chinese Medicine of Guangdong Province, No. 2010463the National Science and Technology"12~(th) Five-years"Major Special-purpose Foundation,No.2011ZX09201-201-01
文摘After gene mutation, the pcDNA3.1/APP595/596 plasmid was transfected into HEK293 cells to establish a cell model of Alzheimer's disease. The cell model was treated with donepezil or compound Danshen tablets after culture for 72 hours. Reverse transcription-PCR showed that the mRNA expression of amyloid protein precursor decreased in all groups following culture for 24 hours, and that there was no significant difference in the amount of decrease between donepezil and compound Danshen tablets. Our results suggest that compound Danshen tablets can reduce expression of the mRNA for amyloid protein precursor in a transgenic cell model of Alzheimer's disease, with similar effects to donepezil.