To observe the chelation of GRP78 with lead （Pb） and its localization changes, astroglial ceils from Wistar rat brain were primarily cultured in medium witb acetate Pb. The processes were terminated at different tim...To observe the chelation of GRP78 with lead （Pb） and its localization changes, astroglial ceils from Wistar rat brain were primarily cultured in medium witb acetate Pb. The processes were terminated at different time points. The immunoprecipitation （IP） and Western blotting were used for GRP78 purification and expression and the Pb concentration was determined by employing atomic absorption spectrophotometry （AAS）. The localization change of GRP78 was observed with colloid gold immunoelectron microscopy. The results showed that the expression of GRP78 was increased significantly in the cells treated with 1.0 μmol/L acetate Pb for 24 h and peaked at 96-192 h （P〈0.01）, and at the 12th day, the expression of GRP78 began to decrease but was still higher than normal （P〈0.05）. Pb content started to increase when cells were treated by acetate Pb for 24 h, and the peak appeared at 8 day （P〈0.01）, and then Pb content decreased gradually, but was still higher than normal （P〈0.05）. GRP78 protein expression began to remarkably increase when it transferred from ER to the cytosol around the nuclei 24 h after treatment with Pb. It is concluded that GRP78 in astroglia could strongly chelate with Pb ions and it might be a target protein of Pb.展开更多
Objective： To observe the effects of lead on levels ofphosphorylated extracellular signal regulated kinase （p-ERK） in the cytoplasm of primary cultures of rat astroglial cells and the possible protective effect of ...Objective： To observe the effects of lead on levels ofphosphorylated extracellular signal regulated kinase （p-ERK） in the cytoplasm of primary cultures of rat astroglial cells and the possible protective effect of basic fibroblast growth factor （bFGF） on lead-induced effects. Methods： The primary astroglia cells from 1-6 d old Wistar rats were cultured. The cells pretreated with the MEK1 （mitogen-activated protein kinase kinase 1） inhibitor PD98059 and bFGF, respectively, were exposed to Pb acetate of different concentrations for different times. Western blotting and reverse transcription polymerase chain reaction （RT-PCR） methods were used to detect the protein and mRNA expressions of ERK. Results： mRNA expression for ERK peaked 15 min after initiation of lead exposure （P〈0.05） and protein expression of p-ERK peaked at 30 min （P〈0.05）. ERK mRNA levels and p-ERK protein levels returned to baseline after 60 and 120 min of lead exposure, respectively （P〉0.05）. The increase in p-ERK levels in lead-treated cells could be inhibited by PD098059. Activation of ERK in the cells by lead was prevented by pretreatment with bFGF. Total ERK protein levels did not change under the same experimental conditions （P〉0.05）. Conclusion： Low-level lead exposure resulted in transient activation of ERK through the MEK pathway, which then returned to basal levels in the continued presence of lead. Exogenous bFGF protected ERK signaling components in astroglia from lead poisoning.展开更多
OBJECTIVE Astroglia support neurons by providing substrates for neuronal metabolism, glutamate clearance and anti-oxidant protection. Nuclear factor erythroid 2-related factor 2(Nrf2) is the main switch of intracellul...OBJECTIVE Astroglia support neurons by providing substrates for neuronal metabolism, glutamate clearance and anti-oxidant protection. Nuclear factor erythroid 2-related factor 2(Nrf2) is the main switch of intracellular antioxidant defense system. Also, Nrf2 signaling is recognized to activate the neurotrophic pathway to replace/protect damaged organelles. Ellagic acid(EA), an excretion component of fruits and nuts, displays anti-oxidant, cardioprotective and antiinflammatory activities. However, few studies have been focused on the neurotrophic properties of EA. Our study investigated whether EA could enhance astroglia neurotrophic effects to support neurons and the underlying mechanisms as well. METHODS Primary neuron-enriched cultures, primary astroglia-enriched cultures and primary neuron-astroglia co-cultures were applied to detect whether pharmacological regulation of astroglia function by EA could be utilized to overcome neuronal death. RESULTS This study indicated that EA promoted neuronal survival. Furtherly, astroglia Nrf2 participate in EA-elicited neuronal survival with the following scenarios. First, EA induced astroglia proliferation, neurotrophic factors release and Nrf2 activation. Second, astroglia-targeted Nrf2 si RNA inhibited EA-mediated astrogliosis,neurotrophic factors excretion and neuronal survival. CONCLUSION EA mediated astroglia Nrf2 activation to enhanced neurotrophic effects on neurons, and these findings might provide new strategies for neurotrophic factor-based treatment of neurodegenerative disease.展开更多
Summary： The regulation of astroglia on synaptic plasticity in the CA1 region of rat hippocampus was examined. Rats were divided into three groups： the newly horn （〈24 h）, the juvenile （28-30 days） and the adul...Summary： The regulation of astroglia on synaptic plasticity in the CA1 region of rat hippocampus was examined. Rats were divided into three groups： the newly horn （〈24 h）, the juvenile （28-30 days） and the adult groups （90-100 days）, with each group having 20 animals. The CA1 region of rat hippocampus was immunohistochemically and electron-microscopically examined, respectively, for the growth of astroglia and the ultrastructure of synapses. The high performance liquid chromatography was employed to determine the cholesterol content of rat hippocampus. In the newly-born rats, a large number of neurons were noted in the hippocampal CA1 region of the newly-born rats, and few astroglia and no synaptic structure were observed. In the juvenile group, a few astroglias and some immature synapses were found, which were less than those in adult rats （P〈0.01）. The cholesterol content was 2.92±0.03 mg/g, 11.20±3.41 mg/g and 12.91±1.25 mg/g for newly born, the juvenile and the adult groups, respectively, with the differences among them being statistically significant （P〈0.01）. Our study suggests that the astrocytes may play an important role in the synaptic formation and functional maturity of hippocampal neurons, which may be related to the secretion of cholesterol from astrocytes.展开更多
Lead(Pb^(2+)),a ubiquitous environmental toxicant,may widely affect the function of many organs or systems of human beings,especially the brain.Although lead is believed to transport into the brain through the blood-b...Lead(Pb^(2+)),a ubiquitous environmental toxicant,may widely affect the function of many organs or systems of human beings,especially the brain.Although lead is believed to transport into the brain through the blood-brain barrier(BBB)and cause direct neuronal injury,growing data have shown that lead exposure could induce brain dysfunction by triggering microglial and astroglial activation,pro-inflammatory cytokine production and inflammatory response,generation of reactive oxygen species and oxidative stress,and finally result in BBB dysfunction and neuronal damage.This review summarizes recent studies regarding microglial and astroglial reaction,neuroinflammation,and neuronal death in the brain following lead insult,suggesting that reactive glial cells may represent a potential target for manipulation of lead-induced neuroinflammatory injury of the brain.展开更多
基金supported by a grant from the National Natural Sciences Foundation of China(No.39970651)
文摘To observe the chelation of GRP78 with lead （Pb） and its localization changes, astroglial ceils from Wistar rat brain were primarily cultured in medium witb acetate Pb. The processes were terminated at different time points. The immunoprecipitation （IP） and Western blotting were used for GRP78 purification and expression and the Pb concentration was determined by employing atomic absorption spectrophotometry （AAS）. The localization change of GRP78 was observed with colloid gold immunoelectron microscopy. The results showed that the expression of GRP78 was increased significantly in the cells treated with 1.0 μmol/L acetate Pb for 24 h and peaked at 96-192 h （P〈0.01）, and at the 12th day, the expression of GRP78 began to decrease but was still higher than normal （P〈0.05）. Pb content started to increase when cells were treated by acetate Pb for 24 h, and the peak appeared at 8 day （P〈0.01）, and then Pb content decreased gradually, but was still higher than normal （P〈0.05）. GRP78 protein expression began to remarkably increase when it transferred from ER to the cytosol around the nuclei 24 h after treatment with Pb. It is concluded that GRP78 in astroglia could strongly chelate with Pb ions and it might be a target protein of Pb.
基金Project (No. 39970651) supported by the National Natural Science Foundation of China
文摘Objective： To observe the effects of lead on levels ofphosphorylated extracellular signal regulated kinase （p-ERK） in the cytoplasm of primary cultures of rat astroglial cells and the possible protective effect of basic fibroblast growth factor （bFGF） on lead-induced effects. Methods： The primary astroglia cells from 1-6 d old Wistar rats were cultured. The cells pretreated with the MEK1 （mitogen-activated protein kinase kinase 1） inhibitor PD98059 and bFGF, respectively, were exposed to Pb acetate of different concentrations for different times. Western blotting and reverse transcription polymerase chain reaction （RT-PCR） methods were used to detect the protein and mRNA expressions of ERK. Results： mRNA expression for ERK peaked 15 min after initiation of lead exposure （P〈0.05） and protein expression of p-ERK peaked at 30 min （P〈0.05）. ERK mRNA levels and p-ERK protein levels returned to baseline after 60 and 120 min of lead exposure, respectively （P〉0.05）. The increase in p-ERK levels in lead-treated cells could be inhibited by PD098059. Activation of ERK in the cells by lead was prevented by pretreatment with bFGF. Total ERK protein levels did not change under the same experimental conditions （P〉0.05）. Conclusion： Low-level lead exposure resulted in transient activation of ERK through the MEK pathway, which then returned to basal levels in the continued presence of lead. Exogenous bFGF protected ERK signaling components in astroglia from lead poisoning.
文摘OBJECTIVE Astroglia support neurons by providing substrates for neuronal metabolism, glutamate clearance and anti-oxidant protection. Nuclear factor erythroid 2-related factor 2(Nrf2) is the main switch of intracellular antioxidant defense system. Also, Nrf2 signaling is recognized to activate the neurotrophic pathway to replace/protect damaged organelles. Ellagic acid(EA), an excretion component of fruits and nuts, displays anti-oxidant, cardioprotective and antiinflammatory activities. However, few studies have been focused on the neurotrophic properties of EA. Our study investigated whether EA could enhance astroglia neurotrophic effects to support neurons and the underlying mechanisms as well. METHODS Primary neuron-enriched cultures, primary astroglia-enriched cultures and primary neuron-astroglia co-cultures were applied to detect whether pharmacological regulation of astroglia function by EA could be utilized to overcome neuronal death. RESULTS This study indicated that EA promoted neuronal survival. Furtherly, astroglia Nrf2 participate in EA-elicited neuronal survival with the following scenarios. First, EA induced astroglia proliferation, neurotrophic factors release and Nrf2 activation. Second, astroglia-targeted Nrf2 si RNA inhibited EA-mediated astrogliosis,neurotrophic factors excretion and neuronal survival. CONCLUSION EA mediated astroglia Nrf2 activation to enhanced neurotrophic effects on neurons, and these findings might provide new strategies for neurotrophic factor-based treatment of neurodegenerative disease.
文摘Summary： The regulation of astroglia on synaptic plasticity in the CA1 region of rat hippocampus was examined. Rats were divided into three groups： the newly horn （〈24 h）, the juvenile （28-30 days） and the adult groups （90-100 days）, with each group having 20 animals. The CA1 region of rat hippocampus was immunohistochemically and electron-microscopically examined, respectively, for the growth of astroglia and the ultrastructure of synapses. The high performance liquid chromatography was employed to determine the cholesterol content of rat hippocampus. In the newly-born rats, a large number of neurons were noted in the hippocampal CA1 region of the newly-born rats, and few astroglia and no synaptic structure were observed. In the juvenile group, a few astroglias and some immature synapses were found, which were less than those in adult rats （P〈0.01）. The cholesterol content was 2.92±0.03 mg/g, 11.20±3.41 mg/g and 12.91±1.25 mg/g for newly born, the juvenile and the adult groups, respectively, with the differences among them being statistically significant （P〈0.01）. Our study suggests that the astrocytes may play an important role in the synaptic formation and functional maturity of hippocampal neurons, which may be related to the secretion of cholesterol from astrocytes.
文摘Lead(Pb^(2+)),a ubiquitous environmental toxicant,may widely affect the function of many organs or systems of human beings,especially the brain.Although lead is believed to transport into the brain through the blood-brain barrier(BBB)and cause direct neuronal injury,growing data have shown that lead exposure could induce brain dysfunction by triggering microglial and astroglial activation,pro-inflammatory cytokine production and inflammatory response,generation of reactive oxygen species and oxidative stress,and finally result in BBB dysfunction and neuronal damage.This review summarizes recent studies regarding microglial and astroglial reaction,neuroinflammation,and neuronal death in the brain following lead insult,suggesting that reactive glial cells may represent a potential target for manipulation of lead-induced neuroinflammatory injury of the brain.
