BACKGROUND： Bile duct ligation （BDL） and subsequent cholestasis are correlated with oxidative stress, hepatocellular injury and fibrosis. Quercetin is a flavonoid with antifibrotic, and hepatoprotective properties....BACKGROUND： Bile duct ligation （BDL） and subsequent cholestasis are correlated with oxidative stress, hepatocellular injury and fibrosis. Quercetin is a flavonoid with antifibrotic, and hepatoprotective properties. However, the molecular mechanism underlying quercetin-mediated hepatoprotection is not fully understood. The current study was to evaluate mecha- nisms of hepatoprotective effect of quercetin in BDL rat model. METHODS： We divided male Wistar rats into 4 groups （n=8 for each）： sham, sham＋quercetin （30 mg/kg per day）, BDL, and BDL＋quercetin （30 mg/kg per day）. Four weeks later, the rats were sacrificed, the blood was collected for liver enzyme mea- surements and liver for the measurement of Racl, Racl-GTP and NOX1 mRNA and protein levels by quantitative PCR and Western blotting, respectively. RESULTS： Quercetin significantly alleviated liver injury in BDL rats as evidenced by histology and reduced liver enzymes. Furthermore, the mRNA and protein expression of Racl, Racl-GTP and NOX1 were significantly increased in BDL rats compared with those in the sham group （P〈0.05）; quercetin treatment reversed these variables back toward normal （P〈0.05）. Another interesting finding was that the antioxidant markers e.g. superoxide dismutase and catalase were elevated in quercetin-treated BDL rats compared to BDL rats （P〈0.05）. CONCLUSION： Quercetin demonstrated hepatoprotective activity against BDL-induced liver injury through increasing antioxidant capacity of the liver tissue, while preventing the production of Racl, Racl-GTP and NOX1 proteins.展开更多
Background Recent studies have suggested that cancer stem cells are one of the major causes for tumor recurrence due to their resistance to radiotherapy and chemotherapy. Although the highly invasive nature of gliobla...Background Recent studies have suggested that cancer stem cells are one of the major causes for tumor recurrence due to their resistance to radiotherapy and chemotherapy. Although the highly invasive nature of glioblastoma （GBM） cells is also implicated in the failure of current therapies, it is not clear how glioma stem cells （GSCs） are involved in invasiveness. Racl activity is necessary for inducing reorganization of actin cytoskeleton and cell movement. In this study, we aimed to investigate the distribution characteristics of CD133＋ cells and Racl＋ cells in GBM as well as Racl activity in CD133＋ GBM cells, and analyze the migration and invasion potential of these cells. Methods A series of 21 patients with GBM were admitted consecutively and received tumor resection in Tianjin Medical University General Hospital during the first half of the year 2011. Tissue specimens were collected both from the peripheral and the central parts for each tumor under magnetic resonance imaging （MRI） navigation guidance. Immunohistochemical staining was used to detect the CD133＋ cells and Racl＋ cells distribution in GBM specimens. Double-labeling immunofluorescence was further used to analyze CD133 and Racl co-expression and the relationship between CD133＋ cells distribution and Racl expression. Serum-free medium culture and magnetic sorting were used to isolate CD133＋ cells from U87 cell line. Racl activation assay was conducted to assess the activation of Racl in CD133＋ and CD133- U87 cells. The migration and invasive ability of CD133＋ and CD133- U87 cells were determined by cell migration and invasion assays in vitro. Student＇s t-test and one-way analysis of variance （ANOVA） test were used to determine statistical significance in this study. Results In the central parts of GBMs, CD133＋ cells were found to cluster around necrosis and occasionally cluster around the vessels under the microscope by immunohistological staining. In the peripheral parts of the tumors, CD133＋ cells were line展开更多
To investigate the effect of autoimmune regulator （AIRE） on phagocytic clearance of apoptotic cells, a recombinant expression vector containing full-length human AIRE cDNA was transfected into 16HBE cells. After inc...To investigate the effect of autoimmune regulator （AIRE） on phagocytic clearance of apoptotic cells, a recombinant expression vector containing full-length human AIRE cDNA was transfected into 16HBE cells. After incubation with transfected 16HBE cells, engulfment of apoptotic HL-60 cells induced by camptothecin was detected by myeloperoxidase （MPO） staining. The change in the expression of Rac 1 in transfected 16HBE cells was determined by RT-PCR and Western blotting. The results showed that the phagocytosis percentage of the experimental group, the mock trans- fection group and the negative control group （non-apoptotic cells） was （25.50±3.67）%, （6.25±1.58）% and （1.0±0.67）%, respectively. Moreover, the expressions of Rac 1 mRNA and protein were up-regulated in AIRE-transfected 16HBE cells, suggesting that AIRE may function as a regulator in the phagocytic clearance of apoptotic cells by promoting the expression of Rac 1.展开更多
Bleeding is a clinical characteristic of severe dengue and may be due to increased vascular permeability. However, the patho- genesis of severe dengue remains unclear. In this study, we showed that the Racl-microfilam...Bleeding is a clinical characteristic of severe dengue and may be due to increased vascular permeability. However, the patho- genesis of severe dengue remains unclear. In this study, we showed that the Racl-microfilament signal pathway was involved in the process of DENV serotype 2 （DENV2） infection in EAhy926 cells. DENV2 infection induced dynamic changes in actin organization, and treatment with Cytochalasin D or Jasplakinolide disrupted microfilament dynamics, reduced DENV2 entry, and inhibited DENV2 assembly and maturation. Racl activities decreased during the early phase and gradually increased by the late phase of infection. Expression of the dominant-negative form of Racl promoted DENV2 entry but inhibited viral as- sembly, maturation and release. Our findings demonstrated that Racl plays an important role in the DENV2 life cycle by reg- ulating actin reorganization in EAhy926 cells. This finding provides further insight into the pathogenesis of severe dengue.展开更多
文摘BACKGROUND： Bile duct ligation （BDL） and subsequent cholestasis are correlated with oxidative stress, hepatocellular injury and fibrosis. Quercetin is a flavonoid with antifibrotic, and hepatoprotective properties. However, the molecular mechanism underlying quercetin-mediated hepatoprotection is not fully understood. The current study was to evaluate mecha- nisms of hepatoprotective effect of quercetin in BDL rat model. METHODS： We divided male Wistar rats into 4 groups （n=8 for each）： sham, sham＋quercetin （30 mg/kg per day）, BDL, and BDL＋quercetin （30 mg/kg per day）. Four weeks later, the rats were sacrificed, the blood was collected for liver enzyme mea- surements and liver for the measurement of Racl, Racl-GTP and NOX1 mRNA and protein levels by quantitative PCR and Western blotting, respectively. RESULTS： Quercetin significantly alleviated liver injury in BDL rats as evidenced by histology and reduced liver enzymes. Furthermore, the mRNA and protein expression of Racl, Racl-GTP and NOX1 were significantly increased in BDL rats compared with those in the sham group （P〈0.05）; quercetin treatment reversed these variables back toward normal （P〈0.05）. Another interesting finding was that the antioxidant markers e.g. superoxide dismutase and catalase were elevated in quercetin-treated BDL rats compared to BDL rats （P〈0.05）. CONCLUSION： Quercetin demonstrated hepatoprotective activity against BDL-induced liver injury through increasing antioxidant capacity of the liver tissue, while preventing the production of Racl, Racl-GTP and NOX1 proteins.
基金This study was supported by a grant from the National Natural Science Foundation of China （No. 81272782）.
文摘Background Recent studies have suggested that cancer stem cells are one of the major causes for tumor recurrence due to their resistance to radiotherapy and chemotherapy. Although the highly invasive nature of glioblastoma （GBM） cells is also implicated in the failure of current therapies, it is not clear how glioma stem cells （GSCs） are involved in invasiveness. Racl activity is necessary for inducing reorganization of actin cytoskeleton and cell movement. In this study, we aimed to investigate the distribution characteristics of CD133＋ cells and Racl＋ cells in GBM as well as Racl activity in CD133＋ GBM cells, and analyze the migration and invasion potential of these cells. Methods A series of 21 patients with GBM were admitted consecutively and received tumor resection in Tianjin Medical University General Hospital during the first half of the year 2011. Tissue specimens were collected both from the peripheral and the central parts for each tumor under magnetic resonance imaging （MRI） navigation guidance. Immunohistochemical staining was used to detect the CD133＋ cells and Racl＋ cells distribution in GBM specimens. Double-labeling immunofluorescence was further used to analyze CD133 and Racl co-expression and the relationship between CD133＋ cells distribution and Racl expression. Serum-free medium culture and magnetic sorting were used to isolate CD133＋ cells from U87 cell line. Racl activation assay was conducted to assess the activation of Racl in CD133＋ and CD133- U87 cells. The migration and invasive ability of CD133＋ and CD133- U87 cells were determined by cell migration and invasion assays in vitro. Student＇s t-test and one-way analysis of variance （ANOVA） test were used to determine statistical significance in this study. Results In the central parts of GBMs, CD133＋ cells were found to cluster around necrosis and occasionally cluster around the vessels under the microscope by immunohistological staining. In the peripheral parts of the tumors, CD133＋ cells were line
文摘To investigate the effect of autoimmune regulator （AIRE） on phagocytic clearance of apoptotic cells, a recombinant expression vector containing full-length human AIRE cDNA was transfected into 16HBE cells. After incubation with transfected 16HBE cells, engulfment of apoptotic HL-60 cells induced by camptothecin was detected by myeloperoxidase （MPO） staining. The change in the expression of Rac 1 in transfected 16HBE cells was determined by RT-PCR and Western blotting. The results showed that the phagocytosis percentage of the experimental group, the mock trans- fection group and the negative control group （non-apoptotic cells） was （25.50±3.67）%, （6.25±1.58）% and （1.0±0.67）%, respectively. Moreover, the expressions of Rac 1 mRNA and protein were up-regulated in AIRE-transfected 16HBE cells, suggesting that AIRE may function as a regulator in the phagocytic clearance of apoptotic cells by promoting the expression of Rac 1.
基金supported by the National Key Programs on Basic Research of China (2011CB504703)the National Natural Science Foundations of China (81301435, 81471957, 81271839, 81401676)Beijing Natural Science Foundation (7144194)
文摘Bleeding is a clinical characteristic of severe dengue and may be due to increased vascular permeability. However, the patho- genesis of severe dengue remains unclear. In this study, we showed that the Racl-microfilament signal pathway was involved in the process of DENV serotype 2 （DENV2） infection in EAhy926 cells. DENV2 infection induced dynamic changes in actin organization, and treatment with Cytochalasin D or Jasplakinolide disrupted microfilament dynamics, reduced DENV2 entry, and inhibited DENV2 assembly and maturation. Racl activities decreased during the early phase and gradually increased by the late phase of infection. Expression of the dominant-negative form of Racl promoted DENV2 entry but inhibited viral as- sembly, maturation and release. Our findings demonstrated that Racl plays an important role in the DENV2 life cycle by reg- ulating actin reorganization in EAhy926 cells. This finding provides further insight into the pathogenesis of severe dengue.
