In the present study, 7 day postnatal C57/BL6 wild-type mice (hyperoxia group) and 7 day postnatal N-methyI-D-aspartate receptor subtype 3A knockout mice (NR3A KO group) were exposed to 75% oxygen and 15% nitrogen...In the present study, 7 day postnatal C57/BL6 wild-type mice (hyperoxia group) and 7 day postnatal N-methyI-D-aspartate receptor subtype 3A knockout mice (NR3A KO group) were exposed to 75% oxygen and 15% nitrogen in a closed container for 5 days. Wild-type mice raised in normoxia served as controls. TdT-mediated dUTP nick end labeling (TUNEL)/neuron-specific nuclear protein (NeuN) and 5-bromo-2'-deoxyuridine (BrdU)/NeuN immunofluorescence staining showed that the number of apoptotic cells and the number of proliferative cells in the dentate subgranular zone significantly increased in the hyperoxia group compared with the control group. However, in the same hyperoxia environment, the number of apoptotic cells and the number of proliferative cells significantly decreased in the NR3A KO group compared with hyperoxia group. TUNEL+/NeuN+ and BrdU+/NeuN~ cells were observed in the NR3A KO and the hyperoxia groups. These results demonstrated that the NR3A gene can promote cell apoptosis and mediate the potential damage in the developing brain induced by exposure to non-physiologically high concentrations of oxygen.展开更多
AIM:To investigate the expression pattern of gamma-aminobutyric acid A(GABAA) receptors in hepatocellular carcinoma(HCC) and indicate the relationship among gamma-aminobutyric acid(GABA),gamma-aminobutyric acid A rece...AIM:To investigate the expression pattern of gamma-aminobutyric acid A(GABAA) receptors in hepatocellular carcinoma(HCC) and indicate the relationship among gamma-aminobutyric acid(GABA),gamma-aminobutyric acid A receptor α3 subunit(GABRA3) and HCC.METHODS:HCC cell line Chang,HepG2,normal liver cell line L-02 and 8 samples of HCC tissues and paired non-cancerous tissues were analyzed with semiquantitative polymerase chain reaction(PCR) for the expression of GABAA receptors.HepG2 cells were treated with gamma-aminobutyric acid(GABA) at serial concentrations(0,1,10,20,40 and 60 μmol/L),and their proliferating abilities were analyzed with the 3-(4,5-methylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay,cell doubling time test,colon formation assay,cell cycle analysis and tumor planted in nude mice.Small interfering RNA was used for knocking down the endogenous GABRA3 in HepG2.Proliferating abilities of these cells treated with or without GABA were analyzed.RESULTS:We identified the overexpression of GABRA3 in HCC cells.Knockdown of endogenous GABRA3 expression in HepG2 attenuated HCC cell growth,suggesting its role in HCC cell viability.We determined the in vitro and in vivo effect of GABA in the proliferation of GABRA3-positive cell lines,and found that GABA increased HCC growth in a dose-dependent manner.Notably,the addition of GABA into the cell culture medium promoted the proliferation of GABRA3-expressing HepG2 cells,but not GABRA3-knockdown HepG2 cells.This means that GABA stimulates HepG2 cell growth through GABRA3.CONCLUSION:GABA and GABRA3 play important roles in HCC development and progression and can be a promising molecular target for the development of new diagnostic and therapeutic strategies for HCC.展开更多
BACKGROUND Single-nucleotide polymorphisms(SNPs)of the serotonin type 3 receptor subunit(HTR3)genes have been associated with psychosomatic symptoms,but it is not clear whether these associations exist in irritable bo...BACKGROUND Single-nucleotide polymorphisms(SNPs)of the serotonin type 3 receptor subunit(HTR3)genes have been associated with psychosomatic symptoms,but it is not clear whether these associations exist in irritable bowel syndrome(IBS).AIM To assess the association of HTR3 polymorphisms with depressive,anxiety,and somatization symptoms in individuals with IBS.METHODS In this retrospective study,623 participants with IBS were recruited from five specialty centers in Germany,Sweden,the United States,the United Kingdom,and Ireland.Depressive,anxiety,and somatization symptoms and sociodemographic characteristics were collected.Four functional SNPs—HTR3A c.-42C>T,HTR3B c.386A>C,HTR3C c.489C>A,and HTR3E c.*76G>A—were genotyped and analyzed using the dominant and recessive models.We also performed separate analyses for sex and IBS subtypes.SNP scores were calculated as the number of minor alleles of the SNPs above.The impact of HTR3C c.489C>A was tested by radioligand-binding and calcium influx assays.RESULTS Depressive and anxiety symptoms significantly worsened with increasing numbers of minor HTR3C c.489C>A alleles in the dominant model(F_(depressive)=7.475,P_(depressive)=0.006;F_(anxiety)=6.535,P_(anxiety)=0.011).A higher SNP score(range 0-6)was linked to a worsened depressive symptoms score(F=7.710,P-linear trend=0.006)in IBS.The potential relevance of the HTR3C SNP was corroborated,showing changes in the expression level of 5-HT3AC variant receptors.CONCLUSION We have provided the first evidence that HTR3C c.489C>A is involved in depressive and anxiety symptoms in individuals with IBS.The SNP score indicated that an increasing number of minor alleles is linked to the worsening of depressive symptoms in IBS.展开更多
Aim The expression of α3 subunit of nicotinic acetylcholine receptor (α3-nAChR) has been demonstra- ted in aorta, adipocyte and macrophage. The objective of the present study was to verify the regulatory roles of ...Aim The expression of α3 subunit of nicotinic acetylcholine receptor (α3-nAChR) has been demonstra- ted in aorta, adipocyte and macrophage. The objective of the present study was to verify the regulatory roles of α3- nAChR in the inflammatory responses of atherosclerosis. Methods The inflammatory indicators were detected in mouse macrophage, adipocytes and mouse aortic endothelial cells (MAECs) after the α3-nAChR was antagonized or after the α3-nAChR gene was silenced. Meanwhile, atherogenesis was induced in the apolipoprotein E knock-out ( ApoE^ -/- ) mice after fed with an atherogenic high-fat diet for 7 weeks. Results In MAECs, the lipopolysaccha- ride (LPS)-stimulated secretions of the adhesion molecules and inflammatory cytokines were significantly enhanced (30%± 80% ) after pretreatment with α-Conotoxin MII (an antagonist for α3-nAChR) or after knock-down with α3-nAChR gene. In adipocytes, the knock-down of α3 gene promoted the generations of the proin? ammatory adi- pokines or cytokines but decreased the production of adiponectin, an anti-inflammatory adipokine, by 29.29 ± 9.43%. In macrophage silenced with α3-nAChR gene, the M1 (classical) activation was predominantly stimula- ted, whereas the M2 (alternative) activation was suppressed. In addition, the amount of the atherosclerotic lesions and the infiltration of the M1 type activated macrophages into the arterial wall were markedly elevated in the α- Conotoxin MII-treated ApoE -/- mice. Conclusion The α3-nAChR may play a pivotal role in regulating the atherogenesis through influencing the inflammatory responses of ECs, macrophages and adipocytes. The mecha- nisms involve the regulations of multiple cell signaling pathways.展开更多
Autoantibody against neuronal nicotinic acetylcholine receptor (nAChR) α3 subunit is implicated in severe autonomic dysfunction in the patients with autoimmune autonomic ganglionopathy (AAG). Although this autoantibo...Autoantibody against neuronal nicotinic acetylcholine receptor (nAChR) α3 subunit is implicated in severe autonomic dysfunction in the patients with autoimmune autonomic ganglionopathy (AAG). Although this autoantibody has been revealed to impair fast excitatory synaptic transmission in autonomic ganglia, its precise mechanism remains unknown. Here, we show that antibody-induced reduction of cell-surface α3 subunits result in impairment of nicotine-evoked Ca2+ influx in stably transfected human embryonic kidney cells. These effects of the antibody were remarkably inhibited by interfering with the endocytic machinery at low-temperature. We conclude that reduction of nAChR in autonomic ganglia can be mediated by the endocytosis of α3 subunits, and resulted in autonomic failure in AAG patients.展开更多
Gamma-aminobutyric acid(GABA)ergic neurons,the most abundant inhibitory neurons in the human brain,have been found to be reduced in many neurological disorders,including Alzheimer's disease and Alzheimer's dis...Gamma-aminobutyric acid(GABA)ergic neurons,the most abundant inhibitory neurons in the human brain,have been found to be reduced in many neurological disorders,including Alzheimer's disease and Alzheimer's disease-related dementia.Our previous study identified the upregulation of microRNA-502-3p(miR-502-3p)and downregulation of GABA type A receptor subunitα-1 in Alzheimer's disease synapses.This study investigated a new molecular relationship between miR-502-3p and GABAergic synapse function.In vitro studies were perfo rmed using the mouse hippocampal neuronal cell line HT22 and miR-502-3p agomiRs and antagomiRs.In silico analysis identified multiple binding sites of miR-502-3p at GABA type A receptor subunitα-1 mRNA.Luciferase assay confirmed that miR-502-3p targets the GABA type A receptor subunitα-1 gene and suppresses the luciferase activity.Furthermore,quantitative reve rse transcription-polymerase chain reaction,miRNA in situ hybridization,immunoblotting,and immunostaining analysis confirmed that overexpression of miR-502-3p reduced the GABA type A receptor subunitα-1 level,while suppression of miR-502-3p increased the level of GABA type A receptor subunitα-1 protein.Notably,as a result of the overexpression of miR-502-3p,cell viability was found to be reduced,and the population of necrotic cells was found to be increased.The whole cell patch-clamp analysis of human-GABA receptor A-α1/β3/γ2L human embryonic kidney(HEK)recombinant cell line also showed that overexpression of miR-502-3p reduced the GABA current and overall GABA function,suggesting a negative correlation between miR-502-3p levels and GABAergic synapse function.Additionally,the levels of proteins associated with Alzheimer s disease were high with miR-502-3p overexpression and reduced with miR-502-3p suppression.The present study provides insight into the molecular mechanism of regulation of GABAergic synapses by miR-502-3p.We propose that micro-RNA,in particular miR-502-3p,could be a potential therapeutic to rget to modulate GABAergic synapse function in neurological disorders,including Alzheimer's disease and Alzheimer's diseaserelated dementia.展开更多
Proteolytic cleavage of tau by asparagine endopeptidase(AEP)creates tau-N368 fragments,which may drive the pathophysiology associated with synaptic dysfunction and memory deterioration in the brain of Alzheimer’s dis...Proteolytic cleavage of tau by asparagine endopeptidase(AEP)creates tau-N368 fragments,which may drive the pathophysiology associated with synaptic dysfunction and memory deterioration in the brain of Alzheimer’s disease patients.Nonetheless,the molecular mechanisms of truncated tau-induced cognitive deficits remain unclear.Evidence suggests that signal transduction and activator of transcription-3(STAT3)is associated with modulating synaptic plasticity,cell apoptosis,and cognitive function.Using luciferase reporter assays,electrophoretic mobility shift assays,western blotting,and immunofluorescence,we found that human tau-N368 accumulation inhibited STAT3 activity by suppressing STAT3 translocation into the nucleus.Overexpression of STAT3 improved tau-N368-induced synaptic deficits and reduced neuronal loss,thereby improving the cognitive deficits in tau-N368 mice.Moreover,in tau-N368 mice,activation of STAT3 increased N-methyl-D-aspartic acid receptor levels,decreased Bcl-2 levels,reversed synaptic damage and neuronal loss,and thereby alleviated cognitive deficits caused by tau-N368.Taken together,STAT3 plays a critical role in truncated tau-related neuropathological changes.This indicates a new mechanism behind the effect of tau-N368 on synapses and memory deficits.STAT3 can be used as a new molecular target to treat tau-N368-induced protein pathology.展开更多
Autophagy has been suggested to participate in the pathology of hypoxic-ischemic brain damage(HIBD).However,its regulatory role in HIBD remains unclear and was thus examined here using a rat model.To induce HIBD,the...Autophagy has been suggested to participate in the pathology of hypoxic-ischemic brain damage(HIBD).However,its regulatory role in HIBD remains unclear and was thus examined here using a rat model.To induce HIBD,the left common carotid artery was ligated in neonatal rats,and the rats were subjected to hypoxia for 2 hours.Some of these rats were intraperitoneally pretreated with the autophagy inhibitor 3-methyladenine(10 m M in 10 μL) or the autophagy stimulator rapamycin(1 g/kg) 1 hour before artery ligation.Our findings demonstrated that hypoxia-ischemia-induced hippocampal injury in neonatal rats was accompanied by increased expression levels of the autophagy-related proteins light chain 3 and Beclin-1 as well as of the AMPA receptor subunit GluR 1,but by reduced expression of GluR 2.Pretreatment with the autophagy inhibitor 3-methyladenine blocked hypoxia-ischemia-induced hippocampal injury,whereas pretreatment with the autophagy stimulator rapamycin significantly augmented hippocampal injury.Additionally,3-methyladenine pretreatment blocked the hypoxia-ischemia-induced upregulation of Glu R1 and downregulation of GluR2 in the hippocampus.By contrast,rapamycin further elevated hippocampal Glu R1 levels and exacerbated decreased GluR2 expression levels in neonates with HIBD.Our results indicate that autophagy inhibition favors the prevention of HIBD in neonatal rats,at least in part,through normalizing Glu R1 and GluR2 expression.展开更多
Objective: Inflammation plays a critical role in secondary brain damage after intracerebral hemorrhage (ICH). However, the mechanisms of inflammatory injury following ICH are still unclear, particularly the involve...Objective: Inflammation plays a critical role in secondary brain damage after intracerebral hemorrhage (ICH). However, the mechanisms of inflammatory injury following ICH are still unclear, particularly the involvement of NLRP3 inflammasome, which are crucial to sterile inflammatory responses. In this study, we aim to test the hypothesis that NLRP3 signaling pathway takes a vital position in ICH-induced sec- ondary inflammatory damage and detect the role of N-methyl-D-aspartic acid receptor 1 (NMDARI) in this progress. Methods: ICH was induced in mice by microinjection of heroin into the striatum. The protein levels of NMDAR1, NMDAR1 phosphorylation, NLRP3 and IL-113 were measured by Western blot. The binding of NMDARI to NLRP3 was detected by immunoprecipitation. Results: The expression of NMDARI, NMDAR1 phosphorylation, NLRP3 and IL-I ~ were rapidly increased after ICH. Heroin treatment enhanced NMDAR1 expression and NMDAR1 phosphorylation, as well in cultured microglial cells treated by hemin. Hemin up-regulated NLRP3 and IL-I]3 level, which was reversed by MK801 (NMDAR antagonist) in vitro. Hemin also promoted the binding of NMDAR1 to NLRP3. Conclusion: Our findings suggest that NMDARI plays a pivotal role in hemin-induced NLRP3-mediated inflammatory damage through synergistic activation.展开更多
基金supported by the National Institutes of Health, USA, No. NS 045810, NS 057255the BasicClinical Scientific Research Foundation Program of the Capital Medical University, China, No. 2006JL19
文摘In the present study, 7 day postnatal C57/BL6 wild-type mice (hyperoxia group) and 7 day postnatal N-methyI-D-aspartate receptor subtype 3A knockout mice (NR3A KO group) were exposed to 75% oxygen and 15% nitrogen in a closed container for 5 days. Wild-type mice raised in normoxia served as controls. TdT-mediated dUTP nick end labeling (TUNEL)/neuron-specific nuclear protein (NeuN) and 5-bromo-2'-deoxyuridine (BrdU)/NeuN immunofluorescence staining showed that the number of apoptotic cells and the number of proliferative cells in the dentate subgranular zone significantly increased in the hyperoxia group compared with the control group. However, in the same hyperoxia environment, the number of apoptotic cells and the number of proliferative cells significantly decreased in the NR3A KO group compared with hyperoxia group. TUNEL+/NeuN+ and BrdU+/NeuN~ cells were observed in the NR3A KO and the hyperoxia groups. These results demonstrated that the NR3A gene can promote cell apoptosis and mediate the potential damage in the developing brain induced by exposure to non-physiologically high concentrations of oxygen.
文摘AIM:To investigate the expression pattern of gamma-aminobutyric acid A(GABAA) receptors in hepatocellular carcinoma(HCC) and indicate the relationship among gamma-aminobutyric acid(GABA),gamma-aminobutyric acid A receptor α3 subunit(GABRA3) and HCC.METHODS:HCC cell line Chang,HepG2,normal liver cell line L-02 and 8 samples of HCC tissues and paired non-cancerous tissues were analyzed with semiquantitative polymerase chain reaction(PCR) for the expression of GABAA receptors.HepG2 cells were treated with gamma-aminobutyric acid(GABA) at serial concentrations(0,1,10,20,40 and 60 μmol/L),and their proliferating abilities were analyzed with the 3-(4,5-methylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay,cell doubling time test,colon formation assay,cell cycle analysis and tumor planted in nude mice.Small interfering RNA was used for knocking down the endogenous GABRA3 in HepG2.Proliferating abilities of these cells treated with or without GABA were analyzed.RESULTS:We identified the overexpression of GABRA3 in HCC cells.Knockdown of endogenous GABRA3 expression in HepG2 attenuated HCC cell growth,suggesting its role in HCC cell viability.We determined the in vitro and in vivo effect of GABA in the proliferation of GABRA3-positive cell lines,and found that GABA increased HCC growth in a dose-dependent manner.Notably,the addition of GABA into the cell culture medium promoted the proliferation of GABRA3-expressing HepG2 cells,but not GABRA3-knockdown HepG2 cells.This means that GABA stimulates HepG2 cell growth through GABRA3.CONCLUSION:GABA and GABRA3 play important roles in HCC development and progression and can be a promising molecular target for the development of new diagnostic and therapeutic strategies for HCC.
基金results in part from collaboration and network activities promoted under the frame of the international network GENIEUR (Genes in Irritable Bowel Syndrome Research Network Europe),which has been funded by the COST program (BM1106, www.GENIEUR.eu)currently supported by the European Society of Neurogastroenterology and Motility (ESNM, www.ESNM.eu)
文摘BACKGROUND Single-nucleotide polymorphisms(SNPs)of the serotonin type 3 receptor subunit(HTR3)genes have been associated with psychosomatic symptoms,but it is not clear whether these associations exist in irritable bowel syndrome(IBS).AIM To assess the association of HTR3 polymorphisms with depressive,anxiety,and somatization symptoms in individuals with IBS.METHODS In this retrospective study,623 participants with IBS were recruited from five specialty centers in Germany,Sweden,the United States,the United Kingdom,and Ireland.Depressive,anxiety,and somatization symptoms and sociodemographic characteristics were collected.Four functional SNPs—HTR3A c.-42C>T,HTR3B c.386A>C,HTR3C c.489C>A,and HTR3E c.*76G>A—were genotyped and analyzed using the dominant and recessive models.We also performed separate analyses for sex and IBS subtypes.SNP scores were calculated as the number of minor alleles of the SNPs above.The impact of HTR3C c.489C>A was tested by radioligand-binding and calcium influx assays.RESULTS Depressive and anxiety symptoms significantly worsened with increasing numbers of minor HTR3C c.489C>A alleles in the dominant model(F_(depressive)=7.475,P_(depressive)=0.006;F_(anxiety)=6.535,P_(anxiety)=0.011).A higher SNP score(range 0-6)was linked to a worsened depressive symptoms score(F=7.710,P-linear trend=0.006)in IBS.The potential relevance of the HTR3C SNP was corroborated,showing changes in the expression level of 5-HT3AC variant receptors.CONCLUSION We have provided the first evidence that HTR3C c.489C>A is involved in depressive and anxiety symptoms in individuals with IBS.The SNP score indicated that an increasing number of minor alleles is linked to the worsening of depressive symptoms in IBS.
文摘Aim The expression of α3 subunit of nicotinic acetylcholine receptor (α3-nAChR) has been demonstra- ted in aorta, adipocyte and macrophage. The objective of the present study was to verify the regulatory roles of α3- nAChR in the inflammatory responses of atherosclerosis. Methods The inflammatory indicators were detected in mouse macrophage, adipocytes and mouse aortic endothelial cells (MAECs) after the α3-nAChR was antagonized or after the α3-nAChR gene was silenced. Meanwhile, atherogenesis was induced in the apolipoprotein E knock-out ( ApoE^ -/- ) mice after fed with an atherogenic high-fat diet for 7 weeks. Results In MAECs, the lipopolysaccha- ride (LPS)-stimulated secretions of the adhesion molecules and inflammatory cytokines were significantly enhanced (30%± 80% ) after pretreatment with α-Conotoxin MII (an antagonist for α3-nAChR) or after knock-down with α3-nAChR gene. In adipocytes, the knock-down of α3 gene promoted the generations of the proin? ammatory adi- pokines or cytokines but decreased the production of adiponectin, an anti-inflammatory adipokine, by 29.29 ± 9.43%. In macrophage silenced with α3-nAChR gene, the M1 (classical) activation was predominantly stimula- ted, whereas the M2 (alternative) activation was suppressed. In addition, the amount of the atherosclerotic lesions and the infiltration of the M1 type activated macrophages into the arterial wall were markedly elevated in the α- Conotoxin MII-treated ApoE -/- mice. Conclusion The α3-nAChR may play a pivotal role in regulating the atherogenesis through influencing the inflammatory responses of ECs, macrophages and adipocytes. The mecha- nisms involve the regulations of multiple cell signaling pathways.
文摘Autoantibody against neuronal nicotinic acetylcholine receptor (nAChR) α3 subunit is implicated in severe autonomic dysfunction in the patients with autoimmune autonomic ganglionopathy (AAG). Although this autoantibody has been revealed to impair fast excitatory synaptic transmission in autonomic ganglia, its precise mechanism remains unknown. Here, we show that antibody-induced reduction of cell-surface α3 subunits result in impairment of nicotine-evoked Ca2+ influx in stably transfected human embryonic kidney cells. These effects of the antibody were remarkably inhibited by interfering with the endocytic machinery at low-temperature. We conclude that reduction of nAChR in autonomic ganglia can be mediated by the endocytosis of α3 subunits, and resulted in autonomic failure in AAG patients.
基金supported by the National Institute on Aging (NIA)National Institutes of Health (NIH)+3 种基金Nos.K99AG065645,R00AG065645R00AG065645-04S1 (to SK)NIH research grants,NINDS,No.R01 NS115834NINDS/NIA,No.R01 NS115834-02S1 (to LG)。
文摘Gamma-aminobutyric acid(GABA)ergic neurons,the most abundant inhibitory neurons in the human brain,have been found to be reduced in many neurological disorders,including Alzheimer's disease and Alzheimer's disease-related dementia.Our previous study identified the upregulation of microRNA-502-3p(miR-502-3p)and downregulation of GABA type A receptor subunitα-1 in Alzheimer's disease synapses.This study investigated a new molecular relationship between miR-502-3p and GABAergic synapse function.In vitro studies were perfo rmed using the mouse hippocampal neuronal cell line HT22 and miR-502-3p agomiRs and antagomiRs.In silico analysis identified multiple binding sites of miR-502-3p at GABA type A receptor subunitα-1 mRNA.Luciferase assay confirmed that miR-502-3p targets the GABA type A receptor subunitα-1 gene and suppresses the luciferase activity.Furthermore,quantitative reve rse transcription-polymerase chain reaction,miRNA in situ hybridization,immunoblotting,and immunostaining analysis confirmed that overexpression of miR-502-3p reduced the GABA type A receptor subunitα-1 level,while suppression of miR-502-3p increased the level of GABA type A receptor subunitα-1 protein.Notably,as a result of the overexpression of miR-502-3p,cell viability was found to be reduced,and the population of necrotic cells was found to be increased.The whole cell patch-clamp analysis of human-GABA receptor A-α1/β3/γ2L human embryonic kidney(HEK)recombinant cell line also showed that overexpression of miR-502-3p reduced the GABA current and overall GABA function,suggesting a negative correlation between miR-502-3p levels and GABAergic synapse function.Additionally,the levels of proteins associated with Alzheimer s disease were high with miR-502-3p overexpression and reduced with miR-502-3p suppression.The present study provides insight into the molecular mechanism of regulation of GABAergic synapses by miR-502-3p.We propose that micro-RNA,in particular miR-502-3p,could be a potential therapeutic to rget to modulate GABAergic synapse function in neurological disorders,including Alzheimer's disease and Alzheimer's diseaserelated dementia.
基金supported in parts by the National Natural Science Foundation of China,Nos.82101501(to QF),and 82201589(to XH)。
文摘Proteolytic cleavage of tau by asparagine endopeptidase(AEP)creates tau-N368 fragments,which may drive the pathophysiology associated with synaptic dysfunction and memory deterioration in the brain of Alzheimer’s disease patients.Nonetheless,the molecular mechanisms of truncated tau-induced cognitive deficits remain unclear.Evidence suggests that signal transduction and activator of transcription-3(STAT3)is associated with modulating synaptic plasticity,cell apoptosis,and cognitive function.Using luciferase reporter assays,electrophoretic mobility shift assays,western blotting,and immunofluorescence,we found that human tau-N368 accumulation inhibited STAT3 activity by suppressing STAT3 translocation into the nucleus.Overexpression of STAT3 improved tau-N368-induced synaptic deficits and reduced neuronal loss,thereby improving the cognitive deficits in tau-N368 mice.Moreover,in tau-N368 mice,activation of STAT3 increased N-methyl-D-aspartic acid receptor levels,decreased Bcl-2 levels,reversed synaptic damage and neuronal loss,and thereby alleviated cognitive deficits caused by tau-N368.Taken together,STAT3 plays a critical role in truncated tau-related neuropathological changes.This indicates a new mechanism behind the effect of tau-N368 on synapses and memory deficits.STAT3 can be used as a new molecular target to treat tau-N368-induced protein pathology.
基金supported by the National Natural Science Foundation of China,No.81471488,81271378,81502157,and 81501291the Key Medical Subjects of Jiangsu Province of China,No.XK201120+3 种基金the Jiangsu Province Key Research and Development of Special Funds in China,No.BE2015644the Science and Technology Project of Suzhou City of China,No.SYSD2013105,SYS201446,SYS201441the Public Health Technology Project of Suzhou City of China,No.SS201536the Department of Pediatrics Clinical Center of Suzhou City of China,No.Szzx201504
文摘Autophagy has been suggested to participate in the pathology of hypoxic-ischemic brain damage(HIBD).However,its regulatory role in HIBD remains unclear and was thus examined here using a rat model.To induce HIBD,the left common carotid artery was ligated in neonatal rats,and the rats were subjected to hypoxia for 2 hours.Some of these rats were intraperitoneally pretreated with the autophagy inhibitor 3-methyladenine(10 m M in 10 μL) or the autophagy stimulator rapamycin(1 g/kg) 1 hour before artery ligation.Our findings demonstrated that hypoxia-ischemia-induced hippocampal injury in neonatal rats was accompanied by increased expression levels of the autophagy-related proteins light chain 3 and Beclin-1 as well as of the AMPA receptor subunit GluR 1,but by reduced expression of GluR 2.Pretreatment with the autophagy inhibitor 3-methyladenine blocked hypoxia-ischemia-induced hippocampal injury,whereas pretreatment with the autophagy stimulator rapamycin significantly augmented hippocampal injury.Additionally,3-methyladenine pretreatment blocked the hypoxia-ischemia-induced upregulation of Glu R1 and downregulation of GluR2 in the hippocampus.By contrast,rapamycin further elevated hippocampal Glu R1 levels and exacerbated decreased GluR2 expression levels in neonates with HIBD.Our results indicate that autophagy inhibition favors the prevention of HIBD in neonatal rats,at least in part,through normalizing Glu R1 and GluR2 expression.
文摘Objective: Inflammation plays a critical role in secondary brain damage after intracerebral hemorrhage (ICH). However, the mechanisms of inflammatory injury following ICH are still unclear, particularly the involvement of NLRP3 inflammasome, which are crucial to sterile inflammatory responses. In this study, we aim to test the hypothesis that NLRP3 signaling pathway takes a vital position in ICH-induced sec- ondary inflammatory damage and detect the role of N-methyl-D-aspartic acid receptor 1 (NMDARI) in this progress. Methods: ICH was induced in mice by microinjection of heroin into the striatum. The protein levels of NMDAR1, NMDAR1 phosphorylation, NLRP3 and IL-113 were measured by Western blot. The binding of NMDARI to NLRP3 was detected by immunoprecipitation. Results: The expression of NMDARI, NMDAR1 phosphorylation, NLRP3 and IL-I ~ were rapidly increased after ICH. Heroin treatment enhanced NMDAR1 expression and NMDAR1 phosphorylation, as well in cultured microglial cells treated by hemin. Hemin up-regulated NLRP3 and IL-I]3 level, which was reversed by MK801 (NMDAR antagonist) in vitro. Hemin also promoted the binding of NMDAR1 to NLRP3. Conclusion: Our findings suggest that NMDARI plays a pivotal role in hemin-induced NLRP3-mediated inflammatory damage through synergistic activation.