Simvastatin induces activation of the serine-threonine-protein kinase Akt and increases survival of isolated human pancreatic islets
Simvastatin induces activation of the serine-threonine-protein kinase Akt and increases survival of isolated human pancreatic islets
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DOI：
10.1097/00007890-200210270-00001
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发表时间：
2002-10-27
期刊：
影响因子：
6.2
通讯作者：
Eckhoff, DE
中科院分区：
文献类型：
--
作者：
Contreras, JL;Smyth, CA;Eckhoff, DE
背景胰岛容易受到胰岛分离和移植过程中发生的无数损伤。研究证实了Akt在调节胰腺β细胞生长和存活中的作用。Akt的激活维持Bad磷酸化并阻止其与线粒体靶点结合，降低caspase-9活性，并阻止叉头转录因子（FKHR）的易位。辛伐他汀激活哺乳动物细胞中的Akt;因此，我们研究了辛伐他汀对人胰岛（HPI）存活的作用。HPI用辛伐他汀治疗，有和没有LY 294002，磷酸肌醇3-激酶抑制剂。PI活力用溴化乙锭-吖啶橙子检测，凋亡用定量分析检测。通过蛋白质印迹分析Akt、Bad、FKHR磷酸化和线粒体细胞色素c释放。通过荧光测定法评估胱天蛋白酶-9活性。在糖尿病NOD-SCID小鼠中，辛伐他汀治疗后移植有限数量的HPI。在胰岛分离后早期证实了低水平的Akt磷酸化（活化）。Akt激活;胰岛活力增加;辛伐他汀处理后，Bad磷酸化、细胞色素c释放、caspase-9活化和FKHR易位减少，LY 294002逆转了这种作用。在没有辛伐他汀的胰岛移植者中，没有人在移植后显示出糖尿病的逆转。相比之下，接受辛伐他汀治疗的胰岛移植者中有58%在移植后30天血糖保持正常。辛伐他汀靶向生存途径对分离的PI产生细胞保护作用。Akt通路的激活是一种潜在的新的治疗方法，以减少功能性胰岛质量的损失，以支持临床胰岛移植的成功。
Background. Pancreatic islets are susceptible to myriad insults that occur during islet isolation and transplantation. Studies demonstrated the role of Akt in regulating pancreatic beta-cell growth and survival. Activation of Akt maintains Bad phosphorylation and prevents its binding to mitochondrial targets, decreases caspase-9 activity, and prevents the translocation of forkhead transcription factors (FKHR). Simvastatin activates Akt in mammalian cells; therefore, we investigated the role of simvastatin on human pancreatic islets (HPI) survival.Methods. HPI were treated with simvastatin, with and without LY294002, an inhibitor of phosphoinositide 3-kinase. PI viability was examined with ethidium bromide-acridine orange, and apoptosis was examined using a quantitative assay. Akt, Bad, FKHR phosphorylation, and mitochondrial cytochrome c release were analyzed by Western blots. Caspase-9 activity was assessed by a fluorometric assay. A limited number of HPI were transplanted after simvastatin treatment in diabetic NOD-SCID mice.Results. Low levels of Akt phosphorylation (activation) were demonstrated early after islet isolation. Akt activation; increase in islet viability; and decrease in Bad phosphorylation, cytochrome c release, caspase-9 activation, and translocation of FKHR were observed after simvastatin treatment, effects reversed by LY294002. Among recipients of islets without simvastatin, none demonstrated reversal of diabetes after the transplant. In contrast, 58% of the recipients given islets treated with simvastatin remained euglycemic 30 days after the transplant.Conclusions. Targeting the survival pathway with simvastatin exerts a cytoprotective effect on isolated PI. Activation of the Akt pathway is a potential new therapeutic approach to reduce loss of functional islet mass to bolster success, in clinical islet transplantation.