Doxorubicin （Dox） is a major anticancer chemotherapeutic agent. However, it causes cardiomyopathy due to the side effect of cardiomyocyte apoptosis. We have previously reported that angiopoietin-1 significantly redu...Doxorubicin （Dox） is a major anticancer chemotherapeutic agent. However, it causes cardiomyopathy due to the side effect of cardiomyocyte apoptosis. We have previously reported that angiopoietin-1 significantly reduced myocardial infarction after ischemic injury and protected cardiomyocytes from oxidative stress-induced apoptosis. It is hypothesized that angiopoietin-1 may protect cardiomyocytes from Dox-induced apoptosis. Cardiomyocytes H9C2 were transfected with adenovirus expressing angiopoietin-1 （Ad5-Ang-1） 24 h before the cells were chal- lenged with Dox at a concentration of 2 ~tmol/L. Ad5-GFP served as the vector control. Cardiomyocyte apoptosis was evaluated using Annexin V-FITC staining and caspase-3 and caspase-8 activity was determined by Western blotting. The results showed that Dox treatment significantly induced cardiomyocyte apoptosis as evidenced by the greater number of Annexin V-FITC stained cells and increases in caspase-3 and caspase-8 activity. In contrast, overexpression of angiopoietin-1 significantly prevented Dox-induced cardiomyocyte apoptosis. To elucidate the mechanisms by which angiopoietin-1 protected cells from Dox-induced apoptosis, we analyzed both extrinsic and intrinsic apoptotic signaling pathways. We observed that angiopoietin-1 prevented Dox-induced activation of both extrinsic and intrinsic apoptotic signaling pathways. Specifically, angiopoietin-1 prevented DOX-induced in- creases in FasL and Bax levels and cleaved caspase-3 and caspase-8 levels in H9C2 cells. In addition, overexpres- sion of angiopoietin-1 also activated the pro-survival phosphoinositide-3 kinase （PI3K）/Akt signaling pathway and decreased Dox-induced nuclear factor-kappaB （NF-~：B） activation. Our data suggest that promoting the expression of angiopoietin-1 could be a potential approach for reducing Dox-induced cardiomyocyte cytoxicity.展开更多
Background Insulin resistance is an underlying feature of both type 2 diabetes and metabolic syndrome. Currently, it is unclear whether nuclear factor （NF）-KB inducing kinase （NIK） plays a role in the development ...Background Insulin resistance is an underlying feature of both type 2 diabetes and metabolic syndrome. Currently, it is unclear whether nuclear factor （NF）-KB inducing kinase （NIK） plays a role in the development of insulin resistance. The present in vivo study investigated the roles of NIK and IKB kinase a （IKKa） in obesity-induced insulin resistance using animal models. Methods NIK expression was evaluated by Western blotting in male Lepob mice and C57BL/6J mice fed a high-fat diet （HFD） （45% fat）. After metformin and sulfasalazine treatment, NIK expression was investigated during the improvement of insulin resistance. Results NIK was increased by about 1-fold in the renal tissues of Lepab mice and C57BL/6J mice fed a HFD for 12 weeks. After 1 and 3 weeks of high-fat feeding, we observed an almost 50% decrease in NIK and IKKa expression in the liver and renal tissues of C57BL/6J mice. NIK expression was significantly lower in the liver and renal tissues of HFD-fed mice that were treated with insulin sensitizers, metformin and sulfasalazine. However, IKKa expression was increased after metformin treatment in both tissues. Conclusion These results suggest a possible role of NIK in the liver and renal tissues of insulin-resistant mice.展开更多
基金supported by the National Natural Science Foundation of China (No. 30971258)the National 973 project of China(NO.2012CB517503)+1 种基金the Key Project of Natural Science Foundation of Jiangsu Province (No. 11KJA310004)Jiangsu "Six Personnel Peak" Talent-Funded Projects
文摘Doxorubicin （Dox） is a major anticancer chemotherapeutic agent. However, it causes cardiomyopathy due to the side effect of cardiomyocyte apoptosis. We have previously reported that angiopoietin-1 significantly reduced myocardial infarction after ischemic injury and protected cardiomyocytes from oxidative stress-induced apoptosis. It is hypothesized that angiopoietin-1 may protect cardiomyocytes from Dox-induced apoptosis. Cardiomyocytes H9C2 were transfected with adenovirus expressing angiopoietin-1 （Ad5-Ang-1） 24 h before the cells were chal- lenged with Dox at a concentration of 2 ~tmol/L. Ad5-GFP served as the vector control. Cardiomyocyte apoptosis was evaluated using Annexin V-FITC staining and caspase-3 and caspase-8 activity was determined by Western blotting. The results showed that Dox treatment significantly induced cardiomyocyte apoptosis as evidenced by the greater number of Annexin V-FITC stained cells and increases in caspase-3 and caspase-8 activity. In contrast, overexpression of angiopoietin-1 significantly prevented Dox-induced cardiomyocyte apoptosis. To elucidate the mechanisms by which angiopoietin-1 protected cells from Dox-induced apoptosis, we analyzed both extrinsic and intrinsic apoptotic signaling pathways. We observed that angiopoietin-1 prevented Dox-induced activation of both extrinsic and intrinsic apoptotic signaling pathways. Specifically, angiopoietin-1 prevented DOX-induced in- creases in FasL and Bax levels and cleaved caspase-3 and caspase-8 levels in H9C2 cells. In addition, overexpres- sion of angiopoietin-1 also activated the pro-survival phosphoinositide-3 kinase （PI3K）/Akt signaling pathway and decreased Dox-induced nuclear factor-kappaB （NF-~：B） activation. Our data suggest that promoting the expression of angiopoietin-1 could be a potential approach for reducing Dox-induced cardiomyocyte cytoxicity.
文摘Background Insulin resistance is an underlying feature of both type 2 diabetes and metabolic syndrome. Currently, it is unclear whether nuclear factor （NF）-KB inducing kinase （NIK） plays a role in the development of insulin resistance. The present in vivo study investigated the roles of NIK and IKB kinase a （IKKa） in obesity-induced insulin resistance using animal models. Methods NIK expression was evaluated by Western blotting in male Lepob mice and C57BL/6J mice fed a high-fat diet （HFD） （45% fat）. After metformin and sulfasalazine treatment, NIK expression was investigated during the improvement of insulin resistance. Results NIK was increased by about 1-fold in the renal tissues of Lepab mice and C57BL/6J mice fed a HFD for 12 weeks. After 1 and 3 weeks of high-fat feeding, we observed an almost 50% decrease in NIK and IKKa expression in the liver and renal tissues of C57BL/6J mice. NIK expression was significantly lower in the liver and renal tissues of HFD-fed mice that were treated with insulin sensitizers, metformin and sulfasalazine. However, IKKa expression was increased after metformin treatment in both tissues. Conclusion These results suggest a possible role of NIK in the liver and renal tissues of insulin-resistant mice.
