Background Two novel presenilin 1 （PS1） mutations, V97L and A136G, were recently found to be involved in the early-onset of Alzheimer＇s disease in two Chinese families. This research aimed to verity their pathologi...Background Two novel presenilin 1 （PS1） mutations, V97L and A136G, were recently found to be involved in the early-onset of Alzheimer＇s disease in two Chinese families. This research aimed to verity their pathological effects. Methods The human neuroblastoma SH-SY5Y cells stably transfected with these two Chinese presenilin 1 mutations were established to explore whether they are sensitive to, or influenced by, serum deprivation and protected by insulin-like growth factor-1 （IGF-1）. Apoptosis rate, glucose uptake of the cells and the expression of glucose transport protein 1 （GLUT1） on cell membranes were examined. Results The V97L or A136G mutants significantly decreased the cells viability and increased the apoptosis rate when compare to PSlwt and mock transfected cells. IGF-1 was found to improve the viability of these two kinds of mutant cells significantly, and to show a protective effect for the mutants when they were treated with trophic deprivation. The glucose uptake of each transfected cell line increased to about 25% after IGF-1 treatment, GLUT1 expression on the cell membrane increased modestly by about 15%-20%. Conclusions Enhanced sensitivity to trophic withdrawal in the cells transfected with the two Chinese PS1 mutations may contribute to the neuron apoptosis, IGF-1 provided a protective effect to cells, possibly through an enhanced glucose transport and mitochondrial activities.展开更多
BACKGROUND： Previous studies have demonstrated that mutant amyloid precursor protein （APP） or presenilin-1 （PS1） genes increase susceptibility to ischemic brain damage induced by middle cerebral artery occlusion....BACKGROUND： Previous studies have demonstrated that mutant amyloid precursor protein （APP） or presenilin-1 （PS1） genes increase susceptibility to ischemic brain damage induced by middle cerebral artery occlusion. Possible mechanisms include over-production of beta-amyloid peptide （Aβ）. OBJECTIVE： Because Aβ is over-produced in the APP/PS1 double-transgenic mouse, the present study focused on mechanisms of increased ischemic damage due to mutant APP and PS1 genes by measuring oxidative stress, mitochondrial function, and calcium homeostasis. DESIGN, TIME AND SETTING： The non-randomized, controlled, in vivo and in vitro experiments were performed at the Medical Research Center, Second Clinical College, Jinan University between May and October 2008. MATERIALS： Male APP transgenic mice carrying the mutant 695swe gene and female PS1 transgenic mice carrying the mutant Leu235Pro gene were donated from the University of Hong Kong. SHSY5Y human neureblastoma cells were purchased from ATCC （Manassas, VA, USA）, and Aβ1-42 was obtained from Sigma-Aldrich （St. Louis, MO, USA）. METHODS： APP transgenic mice were mated with PS1 transgenic mice to produce APP/PS1 double-transgenic mice and wildtype littermates mice. The photothrombotic stroke model was induced in six APP/PS1 double-transgenic and 6 wildtype littermates mice. SHSY5Y human neuroblastoma cells were cultured in vitro, and were divided into 4 groups： Aβ group, cells were exposed to 5 pmol/L Aβ for 24 hours; oxygen-glucose deprivation （OGD） group, cells were exposed to OGD for 1 hour after treatment with sterile, ultra-pure water for 24 hours; OGD＋Aβ group, cells were exposed to OGD and Aβfor 1 hour after treatment with 5 pmol/L Aβ for 24 hours; sham control group： cells were exposed to sterile, ultra-pure water for 25 hours. OGD was achieved by exposing the cells to glucose-free DMEM and placing the cells in an anaerobic chamber flushed with 5% CO2 and 95% N2 （v/v） at 37 ℃ for 1 hour. MAIN OUTCOME MEASURES： TTC staining was used to measure infarct volume 7 days after photothrombotic stroke. Cell viability was evaluated using the MTT kit. Opening of the mitochondrial permeability transition pore, intracellular concentration of superoxide anion, and calcium after OGD were detected with fluorescence intensity of calcein-AM, hydroethidine, and fluo-3/AM. RESULTS： At 7 days after stroke, total infarct volume and cortical infarct volume were significantly greater in the APP/PS1 transgenic mice compared with the wildtype littermates mice （P 〈 0.01）. Aβ, OGD, and Aβ ＋ OGD significantly decreased cell viability and increased fluorescence intensity of hydroethidine and fluo-3/AM （P 〈 0.01）. Compared with the Aβ or OGD group, Aβ ＋ OGD significantly decreased cell viability （P 〈 0.01） and significantly increased fluorescence intensity of calcein-AM, hydroethidine, and fluo-3/AM （P 〈 0.01 or P 〈 0.05）. CONCLUSION： The APP/PS1 double-transgenic mice were more vulnerable to ischemia. The possible mechanisms included enhanced opening of the mitochondrial permeability transition pore, overproduction of superoxide anion due to pore opening, and disturbed calcium homeostasis induced by excess superoxide anion.展开更多
基金This work was supported by National Natural Science Foundation of China （No. 30370494 and 30470615）, National Basic Research 973 Program （No. 2006CB500700）.
文摘Background Two novel presenilin 1 （PS1） mutations, V97L and A136G, were recently found to be involved in the early-onset of Alzheimer＇s disease in two Chinese families. This research aimed to verity their pathological effects. Methods The human neuroblastoma SH-SY5Y cells stably transfected with these two Chinese presenilin 1 mutations were established to explore whether they are sensitive to, or influenced by, serum deprivation and protected by insulin-like growth factor-1 （IGF-1）. Apoptosis rate, glucose uptake of the cells and the expression of glucose transport protein 1 （GLUT1） on cell membranes were examined. Results The V97L or A136G mutants significantly decreased the cells viability and increased the apoptosis rate when compare to PSlwt and mock transfected cells. IGF-1 was found to improve the viability of these two kinds of mutant cells significantly, and to show a protective effect for the mutants when they were treated with trophic deprivation. The glucose uptake of each transfected cell line increased to about 25% after IGF-1 treatment, GLUT1 expression on the cell membrane increased modestly by about 15%-20%. Conclusions Enhanced sensitivity to trophic withdrawal in the cells transfected with the two Chinese PS1 mutations may contribute to the neuron apoptosis, IGF-1 provided a protective effect to cells, possibly through an enhanced glucose transport and mitochondrial activities.
基金Supported by: Shenzhen Science Technology Project from Shenzhen Bureau of Science Technology and Information, No. 200702029Medicial Science Technology Research Fund of Guangdong Province, No. A2008601 & A2007570
文摘BACKGROUND： Previous studies have demonstrated that mutant amyloid precursor protein （APP） or presenilin-1 （PS1） genes increase susceptibility to ischemic brain damage induced by middle cerebral artery occlusion. Possible mechanisms include over-production of beta-amyloid peptide （Aβ）. OBJECTIVE： Because Aβ is over-produced in the APP/PS1 double-transgenic mouse, the present study focused on mechanisms of increased ischemic damage due to mutant APP and PS1 genes by measuring oxidative stress, mitochondrial function, and calcium homeostasis. DESIGN, TIME AND SETTING： The non-randomized, controlled, in vivo and in vitro experiments were performed at the Medical Research Center, Second Clinical College, Jinan University between May and October 2008. MATERIALS： Male APP transgenic mice carrying the mutant 695swe gene and female PS1 transgenic mice carrying the mutant Leu235Pro gene were donated from the University of Hong Kong. SHSY5Y human neureblastoma cells were purchased from ATCC （Manassas, VA, USA）, and Aβ1-42 was obtained from Sigma-Aldrich （St. Louis, MO, USA）. METHODS： APP transgenic mice were mated with PS1 transgenic mice to produce APP/PS1 double-transgenic mice and wildtype littermates mice. The photothrombotic stroke model was induced in six APP/PS1 double-transgenic and 6 wildtype littermates mice. SHSY5Y human neuroblastoma cells were cultured in vitro, and were divided into 4 groups： Aβ group, cells were exposed to 5 pmol/L Aβ for 24 hours; oxygen-glucose deprivation （OGD） group, cells were exposed to OGD for 1 hour after treatment with sterile, ultra-pure water for 24 hours; OGD＋Aβ group, cells were exposed to OGD and Aβfor 1 hour after treatment with 5 pmol/L Aβ for 24 hours; sham control group： cells were exposed to sterile, ultra-pure water for 25 hours. OGD was achieved by exposing the cells to glucose-free DMEM and placing the cells in an anaerobic chamber flushed with 5% CO2 and 95% N2 （v/v） at 37 ℃ for 1 hour. MAIN OUTCOME MEASURES： TTC staining was used to measure infarct volume 7 days after photothrombotic stroke. Cell viability was evaluated using the MTT kit. Opening of the mitochondrial permeability transition pore, intracellular concentration of superoxide anion, and calcium after OGD were detected with fluorescence intensity of calcein-AM, hydroethidine, and fluo-3/AM. RESULTS： At 7 days after stroke, total infarct volume and cortical infarct volume were significantly greater in the APP/PS1 transgenic mice compared with the wildtype littermates mice （P 〈 0.01）. Aβ, OGD, and Aβ ＋ OGD significantly decreased cell viability and increased fluorescence intensity of hydroethidine and fluo-3/AM （P 〈 0.01）. Compared with the Aβ or OGD group, Aβ ＋ OGD significantly decreased cell viability （P 〈 0.01） and significantly increased fluorescence intensity of calcein-AM, hydroethidine, and fluo-3/AM （P 〈 0.01 or P 〈 0.05）. CONCLUSION： The APP/PS1 double-transgenic mice were more vulnerable to ischemia. The possible mechanisms included enhanced opening of the mitochondrial permeability transition pore, overproduction of superoxide anion due to pore opening, and disturbed calcium homeostasis induced by excess superoxide anion.
