Previous studies have indicated that electrical stimulation of the cerebellar fastigial nucleus in rats may reduce brain infarct size, increase the expression of Ku70 in cerebral ischemia/ reperfusion area, and decrea...Previous studies have indicated that electrical stimulation of the cerebellar fastigial nucleus in rats may reduce brain infarct size, increase the expression of Ku70 in cerebral ischemia/ reperfusion area, and decrease the number of apoptotic neurons. However, the anti-apoptotic mechanism of Ku70 remains unclear. In this study, fastigial nucleus stimulation was given to rats 24, 48, and 72 hours before cerebral ischemia/reperfusion injury. Results from the electrical stim- ulation group revealed that rats exhibited a reduction in brain infarct size, a significant increase in the expression of KuT0 in cerebral ischemia/reperfusion regions, and a decreased number of terminal deoxynucleotidyl transferase dUTP nick end labeling （TUNEL）-positive cells. Double immunofluorescence staining revealed no co-localization of Ku70 with TUNEL-positive cells. However, Ku70 partly co-localized with Bax protein in the cytoplasm of rats with cerebral ischemia/reperfusion injury. These findings suggest an involvement of Ku70 with Bax in the cy- toplasm of rats exposed to electrical stimulation of the cerebellar fastigial nucleus, and may thus provide an understanding into the anti-apoptotic activity of KuT0 in cerebral ischemia/reperfu- sion injury.展开更多
Although thousands of DNA damaging events occur in each cell every day,efficient DNA repair pathways have evolved to counteract them. The DNA repair machinery plays a key role in maintaining genomic stability by avoid...Although thousands of DNA damaging events occur in each cell every day,efficient DNA repair pathways have evolved to counteract them. The DNA repair machinery plays a key role in maintaining genomic stability by avoiding the maintenance of mutations. The DNA repair enzymes continuously monitor the chromosomes to correct any damage that is caused by exogenous and endogenous mutagens. If DNA damage in proliferating cells is not repaired because of an inadequate expression of DNA repair genes,it might increase the risk of cancer. In addition to mutations,which can be either inherited or somatically acquired,epigenetic silencing of DNA repair genes has been associated with carcinogenesis. Gastric cancer represents the second highest cause of cancer mortality worldwide. The disease develops from the accumulation of several genetic and epigenetic changes during the lifetime. Among the risk factors,Helicobacter pylori(H. pylori) infection is considered the main driving factor to gastric cancer development. Thus,in this review,we summarize the current knowledge of the role of H. pylori infection on the epigenetic regulation of DNA repair machinery in gastric carcinogenesis.展开更多
Eukaryotic cells contain numerous iron-requiring pro- teins such as iron-sulfur （Fe-S） cluster proteins, hemoproteins and ribonucleotide reductases （RNRs）. These proteins utilize iron as a cofactor and perform key...Eukaryotic cells contain numerous iron-requiring pro- teins such as iron-sulfur （Fe-S） cluster proteins, hemoproteins and ribonucleotide reductases （RNRs）. These proteins utilize iron as a cofactor and perform key roles in DNA replication, DNA repair, metabolic catalysis, iron regulation and cell cycle progression. Disruption of iron homeostasis always impairs the functions of these iron- requiring proteins and is genetically associated with diseases characterized by DNA repair defects in mam- mals. Organisms have evolved multi-layered mecha- nisms to regulate iron balance to ensure genome stability and cell development. This review briefly pro- vides current perspectives on iron homeostasis in yeast and mammals, and mainly summarizes the most recent understandings on iron-requiring protein functions involved in DNA stability maintenance and cell cycle control.展开更多
基金supported by the National Natural Science Foundation of China,No.30860291
文摘Previous studies have indicated that electrical stimulation of the cerebellar fastigial nucleus in rats may reduce brain infarct size, increase the expression of Ku70 in cerebral ischemia/ reperfusion area, and decrease the number of apoptotic neurons. However, the anti-apoptotic mechanism of Ku70 remains unclear. In this study, fastigial nucleus stimulation was given to rats 24, 48, and 72 hours before cerebral ischemia/reperfusion injury. Results from the electrical stim- ulation group revealed that rats exhibited a reduction in brain infarct size, a significant increase in the expression of KuT0 in cerebral ischemia/reperfusion regions, and a decreased number of terminal deoxynucleotidyl transferase dUTP nick end labeling （TUNEL）-positive cells. Double immunofluorescence staining revealed no co-localization of Ku70 with TUNEL-positive cells. However, Ku70 partly co-localized with Bax protein in the cytoplasm of rats with cerebral ischemia/reperfusion injury. These findings suggest an involvement of Ku70 with Bax in the cy- toplasm of rats exposed to electrical stimulation of the cerebellar fastigial nucleus, and may thus provide an understanding into the anti-apoptotic activity of KuT0 in cerebral ischemia/reperfu- sion injury.
文摘Although thousands of DNA damaging events occur in each cell every day,efficient DNA repair pathways have evolved to counteract them. The DNA repair machinery plays a key role in maintaining genomic stability by avoiding the maintenance of mutations. The DNA repair enzymes continuously monitor the chromosomes to correct any damage that is caused by exogenous and endogenous mutagens. If DNA damage in proliferating cells is not repaired because of an inadequate expression of DNA repair genes,it might increase the risk of cancer. In addition to mutations,which can be either inherited or somatically acquired,epigenetic silencing of DNA repair genes has been associated with carcinogenesis. Gastric cancer represents the second highest cause of cancer mortality worldwide. The disease develops from the accumulation of several genetic and epigenetic changes during the lifetime. Among the risk factors,Helicobacter pylori(H. pylori) infection is considered the main driving factor to gastric cancer development. Thus,in this review,we summarize the current knowledge of the role of H. pylori infection on the epigenetic regulation of DNA repair machinery in gastric carcinogenesis.
文摘Eukaryotic cells contain numerous iron-requiring pro- teins such as iron-sulfur （Fe-S） cluster proteins, hemoproteins and ribonucleotide reductases （RNRs）. These proteins utilize iron as a cofactor and perform key roles in DNA replication, DNA repair, metabolic catalysis, iron regulation and cell cycle progression. Disruption of iron homeostasis always impairs the functions of these iron- requiring proteins and is genetically associated with diseases characterized by DNA repair defects in mam- mals. Organisms have evolved multi-layered mecha- nisms to regulate iron balance to ensure genome stability and cell development. This review briefly pro- vides current perspectives on iron homeostasis in yeast and mammals, and mainly summarizes the most recent understandings on iron-requiring protein functions involved in DNA stability maintenance and cell cycle control.
