Recent studies have demonstrated that Notch-1 expression is increased in the hippocampus of Alzheimer＇s disease patients. We speculate that Notch-1 signaling may be involved in PC12 cell apoptosis induced by amyloid ...Recent studies have demonstrated that Notch-1 expression is increased in the hippocampus of Alzheimer＇s disease patients. We speculate that Notch-1 signaling may be involved in PC12 cell apoptosis induced by amyloid beta-peptide （25-35） （Aβ25-35）. In the present study, PC12 cells were cultured with different doses （0, 0.1, 1.0, 10 and 100 nmol/L） of N-[N-（3,5-Difluorophenacetyl）-L-alanyl]-S-phenylglycine t-butyl ester, a Notch-1 signaling pathway inhibitor, for 30 minutes. Then cultured cells were induced with Aβ25-3s for 48 hours. Pretreatment of PC12 cells with high doses of N-[N-（3,5-Difluorophenacetyl）-L-alanyl]-S-phenylglycine t-butyl ester （〉 10 nmol/L） prolonged the survival of PC12 cells after Aβ25-35 induction, decreased the expression of apoptosis-related proteins caspase-3, -8, -9, increased the activity of oxidative stress-related superoxide dismutase and catalase, inhibited the production of active oxygen, and reduced nuclear factor kappa B expression. This study indicates that the Notch-1 signaling pathway plays a pivotal role in Aβ25-35-induced PC12 apoptosis.展开更多
Objective： The aim of the study was to investigate the effect of lipopolysaccharide （LPS） on the expression of nuclear factor kappa B （NF-κB） in 4-（methylitrosamino）-1-（3-pyridyl）-1-butanone （NNK）-mediated...Objective： The aim of the study was to investigate the effect of lipopolysaccharide （LPS） on the expression of nuclear factor kappa B （NF-κB） in 4-（methylitrosamino）-1-（3-pyridyl）-1-butanone （NNK）-mediated primary mouse peritoneal macrophages in vitro. Methods： The activity of peritoneal rnacrophages treated with different concentrations of LPS was detected by MTT assay in rider to find the optimal concentration. Peritoneal macrophages were also treated with NNK （100-500 μM）, with or without LPS for 9 h. The expression of NF-κB was demonstrated via immunocytochemistry （ICC） and Western- blot, respectively. Results： The concentration of LPS at 25 μg/mL was found to be the optimal concentration to improve the activity of peritoneal macrophages （P 〈 0.01）. Simultaneously, LPS （25 μg/mL） increased the expression of NF-κB in both the nucleus and cytoplasm and facilitated transfer of NF-κB to the nucleus. NNK treatment significantly inhibited the expression of NF-κB in a concentration-dependent manner, among the LPS-stimulated or unstimulated peritoneal macrophages, especially when cotreated with LPS （25 μg/mL, P 〈 0.01 ）. Furthermore, NNK treatment （500 μM） with LPS yielded a significant decrease in NF-κB translocation to nucleus and inhibited the expression of NF-κB （P 〈 0.005）. Conclusion： LPS enhances the suppression of NF-κB expression in NNK-mediated mouse peritoneal macrophages, which may provide a theoretical basis for the inhibition of cancer.展开更多
Elevated uric acid causes direct injury to pancreatic β-cells. In this study, we examined the effects of luteolin, an important antioxidant, on uric acid-induced β-cell dysfunction. We first evaluated the effect of ...Elevated uric acid causes direct injury to pancreatic β-cells. In this study, we examined the effects of luteolin, an important antioxidant, on uric acid-induced β-cell dysfunction. We first evaluated the effect of luteolin on nitric oxide （NO） formation in uric acid-stimulated Min6 cells using the Griess method. Next, we performed transient transfection and reporter assays to measure transcriptional activity of nuclear factor （NF）-κB. Western blotting assays were also performed to assess the effect of luteolin on the expression of MafA and inducible NO synthase （iNOS） in uric acid-treated cells. Finally, we evaluated the effect of luteolin on uric acidinduced inhibition of glucose-stimulated insulin secretion （GSIS） in Min6 cells and freshly isolated mouse pancreatic islets. We found that luteolin significantly inhibited uric acid-induced NO production, which was well correlated with reduced expression of iNOS mRNA and protein. Furthermore, decreased activity of NF-κB was implicated in inhibition by luteolin of increased iNOS expression induced by uric acid. Besides, luteolin significantly increased MafA expression in Min6 cells exposed to uric acid, which was reversed by overexpression of iNOS. Moreover, luteolin prevented uric acidinduced inhibition of GSIS in both Min6 cells and mouse islets. In conclusion, luteolin protects pancreatic β-cells from uric acid-induced dysfunction and may confer benefit on the protection of pancreatic β-cells in hyperuricemiaassociated diabetes.展开更多
文摘Recent studies have demonstrated that Notch-1 expression is increased in the hippocampus of Alzheimer＇s disease patients. We speculate that Notch-1 signaling may be involved in PC12 cell apoptosis induced by amyloid beta-peptide （25-35） （Aβ25-35）. In the present study, PC12 cells were cultured with different doses （0, 0.1, 1.0, 10 and 100 nmol/L） of N-[N-（3,5-Difluorophenacetyl）-L-alanyl]-S-phenylglycine t-butyl ester, a Notch-1 signaling pathway inhibitor, for 30 minutes. Then cultured cells were induced with Aβ25-3s for 48 hours. Pretreatment of PC12 cells with high doses of N-[N-（3,5-Difluorophenacetyl）-L-alanyl]-S-phenylglycine t-butyl ester （〉 10 nmol/L） prolonged the survival of PC12 cells after Aβ25-35 induction, decreased the expression of apoptosis-related proteins caspase-3, -8, -9, increased the activity of oxidative stress-related superoxide dismutase and catalase, inhibited the production of active oxygen, and reduced nuclear factor kappa B expression. This study indicates that the Notch-1 signaling pathway plays a pivotal role in Aβ25-35-induced PC12 apoptosis.
文摘Objective： The aim of the study was to investigate the effect of lipopolysaccharide （LPS） on the expression of nuclear factor kappa B （NF-κB） in 4-（methylitrosamino）-1-（3-pyridyl）-1-butanone （NNK）-mediated primary mouse peritoneal macrophages in vitro. Methods： The activity of peritoneal rnacrophages treated with different concentrations of LPS was detected by MTT assay in rider to find the optimal concentration. Peritoneal macrophages were also treated with NNK （100-500 μM）, with or without LPS for 9 h. The expression of NF-κB was demonstrated via immunocytochemistry （ICC） and Western- blot, respectively. Results： The concentration of LPS at 25 μg/mL was found to be the optimal concentration to improve the activity of peritoneal macrophages （P 〈 0.01）. Simultaneously, LPS （25 μg/mL） increased the expression of NF-κB in both the nucleus and cytoplasm and facilitated transfer of NF-κB to the nucleus. NNK treatment significantly inhibited the expression of NF-κB in a concentration-dependent manner, among the LPS-stimulated or unstimulated peritoneal macrophages, especially when cotreated with LPS （25 μg/mL, P 〈 0.01 ）. Furthermore, NNK treatment （500 μM） with LPS yielded a significant decrease in NF-κB translocation to nucleus and inhibited the expression of NF-κB （P 〈 0.005）. Conclusion： LPS enhances the suppression of NF-κB expression in NNK-mediated mouse peritoneal macrophages, which may provide a theoretical basis for the inhibition of cancer.
基金supported by the National Basic Research Program ofChina(2011CB504000,Program 973)the National Natural ScienceFoundation of China(81070656,81171589)the Colleges andUniversities in Jiangsu Province Plans to Graduate Research andInnovation(No.CXZZ12_0562)and Grant(No.100011)from the HealthDepartment of Sichuan Province to D.W
文摘Elevated uric acid causes direct injury to pancreatic β-cells. In this study, we examined the effects of luteolin, an important antioxidant, on uric acid-induced β-cell dysfunction. We first evaluated the effect of luteolin on nitric oxide （NO） formation in uric acid-stimulated Min6 cells using the Griess method. Next, we performed transient transfection and reporter assays to measure transcriptional activity of nuclear factor （NF）-κB. Western blotting assays were also performed to assess the effect of luteolin on the expression of MafA and inducible NO synthase （iNOS） in uric acid-treated cells. Finally, we evaluated the effect of luteolin on uric acidinduced inhibition of glucose-stimulated insulin secretion （GSIS） in Min6 cells and freshly isolated mouse pancreatic islets. We found that luteolin significantly inhibited uric acid-induced NO production, which was well correlated with reduced expression of iNOS mRNA and protein. Furthermore, decreased activity of NF-κB was implicated in inhibition by luteolin of increased iNOS expression induced by uric acid. Besides, luteolin significantly increased MafA expression in Min6 cells exposed to uric acid, which was reversed by overexpression of iNOS. Moreover, luteolin prevented uric acidinduced inhibition of GSIS in both Min6 cells and mouse islets. In conclusion, luteolin protects pancreatic β-cells from uric acid-induced dysfunction and may confer benefit on the protection of pancreatic β-cells in hyperuricemiaassociated diabetes.
