BACKGROUND Tacrolimus(FK506)is a key calcineurin inhibitor used to prevent organ transplant rejection and is effective in improving graft survival.However,it is linked to hyperglycemia and insulin resistance,contribut...BACKGROUND Tacrolimus(FK506)is a key calcineurin inhibitor used to prevent organ transplant rejection and is effective in improving graft survival.However,it is linked to hyperglycemia and insulin resistance,contributing to new-onset diabetes after transplantation and negatively affecting islet function.AIM To study the effects of tacrolimus on the insulin signaling pathway of hepatocytes.METHODS HL7702 cells were treated with different concentrations of tacrolimus(0.1 mg/L,1 mg/L,5 mg/L)for 24 hours.The proteins involved in insulin signaling were detected by Western blotting.RESULTS Compared with the control group,phosphorylation of insulin receptor substrate(IRS)1 at Ser 307 and Ser 323 were increased significantly when the tacrolimus concentration reached 1 and 5 mg/L.Phosphorylation of IRS1 at Ser 1101 was also increased,although not significantly.However,phosphorylation of Ribosomal protein S6 kinase beta-1 at Thr 389 was decreased significantly.The levels of phosphorylated glycogen synthase kinase 3αSer 21 and Ser 9 were increased.Surprisingly,phosphorylation of glycogen synthase at Ser 641 was increased.There was no significant change in the activity of glycogen phosphorylase.CONCLUSION Tacrolimus has no direct effect on hepatic glucose metabolism,but inhibits IRS1-mediated insulin signaling.This may be one of the underlying mechanisms by which tacrolimus induces insulin resistance.展开更多
目的探讨在不同肿瘤细胞中核糖体S6蛋白激酶4(ribosomal protein S6 kinase 4,RSK4)的表达谱是否存在差异,以及预测可能存在的蛋白亚型及其生物学特性。方法提取神经胶质瘤细胞GL261、卵巢癌细胞ID8、乳腺癌细胞4T1和168FARN、结肠癌细...目的探讨在不同肿瘤细胞中核糖体S6蛋白激酶4(ribosomal protein S6 kinase 4,RSK4)的表达谱是否存在差异,以及预测可能存在的蛋白亚型及其生物学特性。方法提取神经胶质瘤细胞GL261、卵巢癌细胞ID8、乳腺癌细胞4T1和168FARN、结肠癌细胞mc38和CT26、胃癌细胞MFC和肺癌细胞LLC1的RNA,采用RT-PCR技术检测RSK4的表达及其剪接异构体,生物信息学分析RSK4的生物学特征及其功能。结果RT-PCR结果显示在GL261、4T1、mc38、CT26、MFC和LLC1中均表达RSK4,且不同的肿瘤细胞中表达了多个剪接异构体,开放阅读框分析RSK4可能至少编码11个蛋白亚型;二级结构分析显示,这些剪接异构体编码的蛋白亚型均由α-螺旋、延伸链、β-转角和无规则卷曲组成,且保守结构域均相同;蛋白互作网络富集分析显示,RSK4主要通过mTOR信号通路和突触持续增强等信号通路在核质和胞浆中发挥激酶的活性。结论RSK4在不同的肿瘤细胞中存在不同的表达谱,可能产生多种氮端不同的蛋白异构体,能够通过多种信号通路参与不同的生物学途径。展开更多
文摘BACKGROUND Tacrolimus(FK506)is a key calcineurin inhibitor used to prevent organ transplant rejection and is effective in improving graft survival.However,it is linked to hyperglycemia and insulin resistance,contributing to new-onset diabetes after transplantation and negatively affecting islet function.AIM To study the effects of tacrolimus on the insulin signaling pathway of hepatocytes.METHODS HL7702 cells were treated with different concentrations of tacrolimus(0.1 mg/L,1 mg/L,5 mg/L)for 24 hours.The proteins involved in insulin signaling were detected by Western blotting.RESULTS Compared with the control group,phosphorylation of insulin receptor substrate(IRS)1 at Ser 307 and Ser 323 were increased significantly when the tacrolimus concentration reached 1 and 5 mg/L.Phosphorylation of IRS1 at Ser 1101 was also increased,although not significantly.However,phosphorylation of Ribosomal protein S6 kinase beta-1 at Thr 389 was decreased significantly.The levels of phosphorylated glycogen synthase kinase 3αSer 21 and Ser 9 were increased.Surprisingly,phosphorylation of glycogen synthase at Ser 641 was increased.There was no significant change in the activity of glycogen phosphorylase.CONCLUSION Tacrolimus has no direct effect on hepatic glucose metabolism,but inhibits IRS1-mediated insulin signaling.This may be one of the underlying mechanisms by which tacrolimus induces insulin resistance.
文摘目的探讨在不同肿瘤细胞中核糖体S6蛋白激酶4(ribosomal protein S6 kinase 4,RSK4)的表达谱是否存在差异,以及预测可能存在的蛋白亚型及其生物学特性。方法提取神经胶质瘤细胞GL261、卵巢癌细胞ID8、乳腺癌细胞4T1和168FARN、结肠癌细胞mc38和CT26、胃癌细胞MFC和肺癌细胞LLC1的RNA,采用RT-PCR技术检测RSK4的表达及其剪接异构体,生物信息学分析RSK4的生物学特征及其功能。结果RT-PCR结果显示在GL261、4T1、mc38、CT26、MFC和LLC1中均表达RSK4,且不同的肿瘤细胞中表达了多个剪接异构体,开放阅读框分析RSK4可能至少编码11个蛋白亚型;二级结构分析显示,这些剪接异构体编码的蛋白亚型均由α-螺旋、延伸链、β-转角和无规则卷曲组成,且保守结构域均相同;蛋白互作网络富集分析显示,RSK4主要通过mTOR信号通路和突触持续增强等信号通路在核质和胞浆中发挥激酶的活性。结论RSK4在不同的肿瘤细胞中存在不同的表达谱,可能产生多种氮端不同的蛋白异构体,能够通过多种信号通路参与不同的生物学途径。
