BACKGROUND： Neural stem cell （NSC） survival is closely associated with cell apoptosis in ischemic-hypoxic regions following transplantation. Numerous studies have revealed that X-box binding protein 1 （XBP1） is a...BACKGROUND： Neural stem cell （NSC） survival is closely associated with cell apoptosis in ischemic-hypoxic regions following transplantation. Numerous studies have revealed that X-box binding protein 1 （XBP1） is a transcription factor during endoplasmic reticulum unfolded protein response and is essential for cell survival, differentiation, and anti-apoptotic effects. OBJECTIVE： To determine the effects of the XBP1 gene on NSC proliferation and apoptosis under hypoxic conditions following XBP1 gene transfection into rat embryonic hippocampal NSCs using recombinant adenovirus vector. DESIGN, TIME AND SETTING： In vitro experiments were performed at the Laboratory of Cell Biology of Jilin University and Laboratory of Proteomics, Department of Neurology, Jilin University China from September 2008 to November 2009. MATERIALS： Recombinant adenovirus package XBP1 gene and Ad-XBPl-enhanced green fluorescent protein plasmid （Guangzhou Easywin BioMed Technology, China）, rabbit anti-XBP1 and its target gene estrogen receptor degradation-enhancing a-mannosidase-like protein （EDEM） glucose-regulated protein 78 （GRP78）, anti-apoptotic molecule Bcl-2 and proapoptotic molecule Bax polyclonal antibody （Santa Cruz Biotechnology, Inc., Santa Cruz, CA, USA）, and COCI2 （Sigma, St. Louis, MO, USA） were used in the present study. METHODS： Hippocampi from embryonic, Sprague Dawley rats on gestational day 16 were harvested for NSC isolation and cloning, followed by immunofluorescence for Nestin and sub-culturing. The recombinant adenovirus Ad-XBPl-enhanced green fluorescent protein plasmid was transfected into rat embryonic hippocampal NSCs, and then CoCl2 was applied to induce hypoxia. MAIN OUTCOME MEASURES： Cell quantification and 3-（4, 5-dimethylthiazol-2-yl）-2, 5-diphenyltetrazolium bromide colorimetric assay were utilized to detect proliferation in XBPl-transfected NSCs for 7 consecutive days. Western blot assay was utilized to quantify XBP1 GRP78, EDEM, Bcl-2, and Bax expression. Flow cytometry was used to measure apoptosis. RESULTS： NSC proliferation was significantly enhanced following XBP1 gene transfection （P 〈 0.05）. Under hypoxic conditions, GRP78, EDEM, and Bcl-2 levels increased, but Bax levels decreased. In addition, NSC apoptosis decreased following transfection （P 〈 0.05）. CONCLUSION： The XBP1 gene was successfully transfected into rat embryonic hippocampal NSCs using a recombinant adenovirus vector. NSC proliferation following transfection, as well as anti-apoptotic effects under hypoxia, was significantly increased.展开更多
X-box-binding protein-1 （XBP-1） is an essential transcription factor in endoplasmic reticulum stress In this study, XBP-1 gene-transfected neural stem cells （NSCs） were transplanted into lesion sites to ensure sta...X-box-binding protein-1 （XBP-1） is an essential transcription factor in endoplasmic reticulum stress In this study, XBP-1 gene-transfected neural stem cells （NSCs） were transplanted into lesion sites to ensure stability and persistent expression of XBP-1, resulting in the exertion of anti-apoptotic effects. Simultaneously, XBP-1 gene transfection promotes the survival and differentiation of transplanted NSCs. Results from this study demonstrated that survival, proliferation and differentiation of XBP-1 g^ne-modified NSCs were enhanced when compared to unmodified NSCs at 28 days post-transplantation （P 〈 0.05）. A diminished number of apoptotic neural cells increased Bcl-2 expression and reduced Bax expression, and were observed in the ischemic region of the XBP-1-NSCs group （P 〈 0.05）. These results indicated that modification of the XBP-1 gene enhances the survival and migration of NSCs in vivo and decreases the occurrence of apoptosis.展开更多
X-box-binding protein 1-transfected neural stem cells were transplanted into the right lateral ventricles of rats with rotenone-induced Parkinson＇s disease. The survival capacities and differentiation rates of cells ...X-box-binding protein 1-transfected neural stem cells were transplanted into the right lateral ventricles of rats with rotenone-induced Parkinson＇s disease. The survival capacities and differentiation rates of cells expressing the dopaminergic marker tyrosine hydroxylase were higher in X-box-binding protein 1-transfected neural stem cells compared to non-transfected cells. Moreover, dopamine and 3,4-dihydroxyphenylacetic acid levels in the substantia nigra were significantly increased, α-synuclein expression was decreased, and neurological behaviors were significantly ameliorated in rats following transplantation of X-box-binding protein 1-transfected neural stem cells. These results indicate that transplantation of X-box-binding protein 1-transfected neural stem cells can promote stem cell survival and differentiation into dopaminergic neurons, increase dopamine and 3,4-dihydroxyphenylacetic acid levels, reduce α-synuclein aggregation in the substantia nigra, and improve the symptoms of Parkinson＇s disease in rats.展开更多
Background：A high consumption of fructose leads to hepatic steatosis.About 20-30% of triglycerides are synthesized via de novo lipogenesis.Some studies showed that endoplasmic reticulum stress （ERS） is involved in ...Background：A high consumption of fructose leads to hepatic steatosis.About 20-30% of triglycerides are synthesized via de novo lipogenesis.Some studies showed that endoplasmic reticulum stress （ERS） is involved in this process,while others showed that a lipotoxic environment directly influences ER homeostasis.Here,our aim was to investigate the causal relationship between ERS and fatty acid synthesis and the effect of X-box binding protein-1 （XBP-1）,one marker of ERS,on hepatic lipid accumulation stimulated by high fructose.Methods：HepG2 cells were incubated with different concentrations of fructose.Upstream regulators of de novo lipogenesis （i.e.,carbohydrate response element-binding protein [ChREBP] and sterol regulatory element-binding protein 1 c [SREBP-lc]） were measured by polymerase chain reaction and key lipogenic enzymes （acetyl-CoA carboxylase [ACC],fatty acid synthase [FAS],and stearoyl-CoA desaturase-1 [SCD-1]） by Western blotting.The same lipogenesis-associated factors were then evaluated after exposure of HepG2 cells to high fructose followed by the ERS inhibitor tauroursodeoxycholic acid （TUDCA） or the ERS inducer thapsigargin.Finally,the same lipogenesis-associated factors were evaluated in HepG2 cells after XBP-1 upregulation or downregulation through cell transfection.Results：Exposure to high fructose increased triglyceride levels in a dose-and time-dependent manner and significantly increased mRNA levels of SREBP-1c and ChREBP and protein levels ofFAS,ACC,and SCD-1,concomitant with XBP-1 conversion to an active spliced form.Lipogenesis-associated factors induced by high fructose were inhibited by TUDCA and induced by thapsigargin.Triglyceride level in XBP-l-deficient group decreased significantly compared with high-fructose group （4.41 ± 0.54 μmol/g vs.6.52 ± 0.38 μmol/g,P 〈 0.001）,as mRNA expressions of SREBP-1c （2.92 ± 0.46 vs.5.08 ± 0.41,P 〈 0.01） and protein levels of FAS （0.53 ± 0.06 vs.0.85 ± 0.05,P =0.01）,SCD-1 （0.65 ± 0.06 vs.0.90 ± 0.04,P =0.04）,and ACC （0.38 ± 0.03 vs.0.95 ± 0.06,P 〈 0.01） decreased.Conversely,levels of triglyceride （4.22 ± 0.54 μmol/g vs.2.41 ± 0.35 μmol/g,P 〈 0.001）,mRNA expression of SREBP-1c （2.70 ± 0.33 vs.1.00 ± 0.00,P 〈 0.0 1）,and protein expression of SCD-1 （0.93 ± 0.06 vs.0.26 ± 0.05,P 〈 0.01）,ACC （0.98 ± 0.09 vs.0.43 ± 0.03,P 〈 0.01）,and FAS （0.90 ± 0.33 vs.0.71 ±4 0.02,P =0.04） in XBP-ls-upregulated group increased compared with the untransfected group.Conclusions：ERS is associated with de novo lipogenesis,and XBP-1 partially mediates high-fructose-induced lipid accumulation in HepG2 cells through augmentation of de novo lipogenesis.展开更多
We previously reported that miR-124-3p is markedly upregulated in microglia-derived exosomes following repetitive mild traumatic brain injury.However,its impact on neuronal endoplasmic reticulum stress following repet...We previously reported that miR-124-3p is markedly upregulated in microglia-derived exosomes following repetitive mild traumatic brain injury.However,its impact on neuronal endoplasmic reticulum stress following repetitive mild traumatic brain injury remains unclear.In this study,we first used an HT22 scratch injury model to mimic traumatic brain injury,then co-cultured the HT22 cells with BV2 microglia expressing high levels of miR-124-3p.We found that exosomes containing high levels of miR-124-3p attenuated apoptosis and endoplasmic reticulum stress.Furthermore,luciferase reporter assay analysis confirmed that miR-124-3p bound specifically to the endoplasmic reticulum stress-related protein IRE1α,while an IRE1αfunctional salvage experiment confirmed that miR-124-3p targeted IRE1αand reduced its expression,thereby inhibiting endoplasmic reticulum stress in injured neurons.Finally,we delivered microglia-derived exosomes containing miR-124-3p intranasally to a mouse model of repetitive mild traumatic brain injury and found that endoplasmic reticulum stress and apoptosis levels in hippocampal neurons were significantly reduced.These findings suggest that,after repetitive mild traumatic brain injury,miR-124-3 can be transferred from microglia-derived exosomes to injured neurons,where it exerts a neuroprotective effect by inhibiting endoplasmic reticulum stress.Therefore,microglia-derived exosomes containing miR-124-3p may represent a novel therapeutic strategy for repetitive mild traumatic brain injury.展开更多
文摘BACKGROUND： Neural stem cell （NSC） survival is closely associated with cell apoptosis in ischemic-hypoxic regions following transplantation. Numerous studies have revealed that X-box binding protein 1 （XBP1） is a transcription factor during endoplasmic reticulum unfolded protein response and is essential for cell survival, differentiation, and anti-apoptotic effects. OBJECTIVE： To determine the effects of the XBP1 gene on NSC proliferation and apoptosis under hypoxic conditions following XBP1 gene transfection into rat embryonic hippocampal NSCs using recombinant adenovirus vector. DESIGN, TIME AND SETTING： In vitro experiments were performed at the Laboratory of Cell Biology of Jilin University and Laboratory of Proteomics, Department of Neurology, Jilin University China from September 2008 to November 2009. MATERIALS： Recombinant adenovirus package XBP1 gene and Ad-XBPl-enhanced green fluorescent protein plasmid （Guangzhou Easywin BioMed Technology, China）, rabbit anti-XBP1 and its target gene estrogen receptor degradation-enhancing a-mannosidase-like protein （EDEM） glucose-regulated protein 78 （GRP78）, anti-apoptotic molecule Bcl-2 and proapoptotic molecule Bax polyclonal antibody （Santa Cruz Biotechnology, Inc., Santa Cruz, CA, USA）, and COCI2 （Sigma, St. Louis, MO, USA） were used in the present study. METHODS： Hippocampi from embryonic, Sprague Dawley rats on gestational day 16 were harvested for NSC isolation and cloning, followed by immunofluorescence for Nestin and sub-culturing. The recombinant adenovirus Ad-XBPl-enhanced green fluorescent protein plasmid was transfected into rat embryonic hippocampal NSCs, and then CoCl2 was applied to induce hypoxia. MAIN OUTCOME MEASURES： Cell quantification and 3-（4, 5-dimethylthiazol-2-yl）-2, 5-diphenyltetrazolium bromide colorimetric assay were utilized to detect proliferation in XBPl-transfected NSCs for 7 consecutive days. Western blot assay was utilized to quantify XBP1 GRP78, EDEM, Bcl-2, and Bax expression. Flow cytometry was used to measure apoptosis. RESULTS： NSC proliferation was significantly enhanced following XBP1 gene transfection （P 〈 0.05）. Under hypoxic conditions, GRP78, EDEM, and Bcl-2 levels increased, but Bax levels decreased. In addition, NSC apoptosis decreased following transfection （P 〈 0.05）. CONCLUSION： The XBP1 gene was successfully transfected into rat embryonic hippocampal NSCs using a recombinant adenovirus vector. NSC proliferation following transfection, as well as anti-apoptotic effects under hypoxia, was significantly increased.
文摘X-box-binding protein-1 （XBP-1） is an essential transcription factor in endoplasmic reticulum stress In this study, XBP-1 gene-transfected neural stem cells （NSCs） were transplanted into lesion sites to ensure stability and persistent expression of XBP-1, resulting in the exertion of anti-apoptotic effects. Simultaneously, XBP-1 gene transfection promotes the survival and differentiation of transplanted NSCs. Results from this study demonstrated that survival, proliferation and differentiation of XBP-1 g^ne-modified NSCs were enhanced when compared to unmodified NSCs at 28 days post-transplantation （P 〈 0.05）. A diminished number of apoptotic neural cells increased Bcl-2 expression and reduced Bax expression, and were observed in the ischemic region of the XBP-1-NSCs group （P 〈 0.05）. These results indicated that modification of the XBP-1 gene enhances the survival and migration of NSCs in vivo and decreases the occurrence of apoptosis.
文摘X-box-binding protein 1-transfected neural stem cells were transplanted into the right lateral ventricles of rats with rotenone-induced Parkinson＇s disease. The survival capacities and differentiation rates of cells expressing the dopaminergic marker tyrosine hydroxylase were higher in X-box-binding protein 1-transfected neural stem cells compared to non-transfected cells. Moreover, dopamine and 3,4-dihydroxyphenylacetic acid levels in the substantia nigra were significantly increased, α-synuclein expression was decreased, and neurological behaviors were significantly ameliorated in rats following transplantation of X-box-binding protein 1-transfected neural stem cells. These results indicate that transplantation of X-box-binding protein 1-transfected neural stem cells can promote stem cell survival and differentiation into dopaminergic neurons, increase dopamine and 3,4-dihydroxyphenylacetic acid levels, reduce α-synuclein aggregation in the substantia nigra, and improve the symptoms of Parkinson＇s disease in rats.
文摘Background：A high consumption of fructose leads to hepatic steatosis.About 20-30% of triglycerides are synthesized via de novo lipogenesis.Some studies showed that endoplasmic reticulum stress （ERS） is involved in this process,while others showed that a lipotoxic environment directly influences ER homeostasis.Here,our aim was to investigate the causal relationship between ERS and fatty acid synthesis and the effect of X-box binding protein-1 （XBP-1）,one marker of ERS,on hepatic lipid accumulation stimulated by high fructose.Methods：HepG2 cells were incubated with different concentrations of fructose.Upstream regulators of de novo lipogenesis （i.e.,carbohydrate response element-binding protein [ChREBP] and sterol regulatory element-binding protein 1 c [SREBP-lc]） were measured by polymerase chain reaction and key lipogenic enzymes （acetyl-CoA carboxylase [ACC],fatty acid synthase [FAS],and stearoyl-CoA desaturase-1 [SCD-1]） by Western blotting.The same lipogenesis-associated factors were then evaluated after exposure of HepG2 cells to high fructose followed by the ERS inhibitor tauroursodeoxycholic acid （TUDCA） or the ERS inducer thapsigargin.Finally,the same lipogenesis-associated factors were evaluated in HepG2 cells after XBP-1 upregulation or downregulation through cell transfection.Results：Exposure to high fructose increased triglyceride levels in a dose-and time-dependent manner and significantly increased mRNA levels of SREBP-1c and ChREBP and protein levels ofFAS,ACC,and SCD-1,concomitant with XBP-1 conversion to an active spliced form.Lipogenesis-associated factors induced by high fructose were inhibited by TUDCA and induced by thapsigargin.Triglyceride level in XBP-l-deficient group decreased significantly compared with high-fructose group （4.41 ± 0.54 μmol/g vs.6.52 ± 0.38 μmol/g,P 〈 0.001）,as mRNA expressions of SREBP-1c （2.92 ± 0.46 vs.5.08 ± 0.41,P 〈 0.01） and protein levels of FAS （0.53 ± 0.06 vs.0.85 ± 0.05,P =0.01）,SCD-1 （0.65 ± 0.06 vs.0.90 ± 0.04,P =0.04）,and ACC （0.38 ± 0.03 vs.0.95 ± 0.06,P 〈 0.01） decreased.Conversely,levels of triglyceride （4.22 ± 0.54 μmol/g vs.2.41 ± 0.35 μmol/g,P 〈 0.001）,mRNA expression of SREBP-1c （2.70 ± 0.33 vs.1.00 ± 0.00,P 〈 0.0 1）,and protein expression of SCD-1 （0.93 ± 0.06 vs.0.26 ± 0.05,P 〈 0.01）,ACC （0.98 ± 0.09 vs.0.43 ± 0.03,P 〈 0.01）,and FAS （0.90 ± 0.33 vs.0.71 ±4 0.02,P =0.04） in XBP-ls-upregulated group increased compared with the untransfected group.Conclusions：ERS is associated with de novo lipogenesis,and XBP-1 partially mediates high-fructose-induced lipid accumulation in HepG2 cells through augmentation of de novo lipogenesis.
基金supported by the Haihe Laboratory of Cell Ecosystem Innovation Fund,No.22HHXBSS00047(to PL)the National Natural Science Foundation of China,Nos.82072166(to PL),82071394(to XG)+4 种基金Science and Technology Planning Project of Tianjin,No.20YFZCSY00030(to PL)Science and Technology Project of Tianjin Municipal Health Commission,No.TJWJ2021QN005(to XG)Tianjin Key Medical Discipline(Specialty)Construction Project,No.TJYXZDXK-006ATianjin Municipal Education Commission Scientific Research Program Project,No.2020KJ164(to JZ)China Postdoctoral Science Foundation,No.2022M712392(to ZY).
文摘We previously reported that miR-124-3p is markedly upregulated in microglia-derived exosomes following repetitive mild traumatic brain injury.However,its impact on neuronal endoplasmic reticulum stress following repetitive mild traumatic brain injury remains unclear.In this study,we first used an HT22 scratch injury model to mimic traumatic brain injury,then co-cultured the HT22 cells with BV2 microglia expressing high levels of miR-124-3p.We found that exosomes containing high levels of miR-124-3p attenuated apoptosis and endoplasmic reticulum stress.Furthermore,luciferase reporter assay analysis confirmed that miR-124-3p bound specifically to the endoplasmic reticulum stress-related protein IRE1α,while an IRE1αfunctional salvage experiment confirmed that miR-124-3p targeted IRE1αand reduced its expression,thereby inhibiting endoplasmic reticulum stress in injured neurons.Finally,we delivered microglia-derived exosomes containing miR-124-3p intranasally to a mouse model of repetitive mild traumatic brain injury and found that endoplasmic reticulum stress and apoptosis levels in hippocampal neurons were significantly reduced.These findings suggest that,after repetitive mild traumatic brain injury,miR-124-3 can be transferred from microglia-derived exosomes to injured neurons,where it exerts a neuroprotective effect by inhibiting endoplasmic reticulum stress.Therefore,microglia-derived exosomes containing miR-124-3p may represent a novel therapeutic strategy for repetitive mild traumatic brain injury.
