Clinical Research & Development, Department of Anesthesiology, and University of Colorado Cancer Center, University of Colorado Denver, Aurora, Colorado 80045, USA.
Chem Res Toxicol. 2010 Mar 15;23(3):608-19. doi: 10.1021/tx900351q.
Coadministration of the calcineurin inhibitor cyclosporine (CsA) and the mTOR inhibitors sirolimus (SRL) or everolimus (RAD) increases the efficacy of immunosuppression after organ transplantation. Neurotoxicity of CsA is a major clinical problem. Our goal was to assess the effects of CsA, SRL, and RAD on brain cell metabolism. The studies included the comparison of immunosuppressant-mediated effects on glucose metabolism, energy production, and reactive oxygen species (ROS) formation in perfused rat brain slices, primary rat astrocytes, and C6 glioma cells. In brain slices and astrocytes, CsA inhibited Krebs cycle metabolism, while activating anaerobic glycolysis, most likely to compensate for the inhibition of mitochondrial energy production. SRL and RAD inhibited cytosolic glycolysis but did not cause changes in mitochondrial energy production. CsA + SRL inhibited Krebs cycle and glycolysis, thus reducing the ability of the cell to compensate for the negative effects of CsA on mitochondrial nucleoside triphosphate synthesis. In contrast to SRL at the concentrations tested, RAD reduced the CsA-induced ROS formation and antagonized CsA-induced effects on glucose and energy metabolism. Surprisingly, in C6 cells, SRL and RAD exposure resulted in high ROS concentrations without significant impairment of cell metabolism. Our results suggested that SRL enhances CsA-induced ROS formation and negative metabolic effects in brain cells, while RAD seems to antagonize the CsA effects. However, the three models showed different metabolic responses when challenged with the study drugs. In contrast to SRL, RAD enhances ROS formation in C6 glioma cells but has only minor effects on normal rat brain tissue.
环孢素（CsA）与雷帕霉素（SRL）或依维莫司（RAD）联合使用可增加器官移植后免疫抑制的疗效。CsA 的神经毒性是一个主要的临床问题。我们的目标是评估 CsA、SRL 和 RAD 对脑细胞代谢的影响。这些研究包括比较免疫抑制剂对灌流大鼠脑片、原代大鼠星形胶质细胞和 C6 神经胶质瘤细胞中葡萄糖代谢、能量产生和活性氧（ROS）形成的介导作用。在脑片和星形胶质细胞中，CsA 抑制三羧酸循环代谢，同时激活无氧糖酵解，很可能是为了补偿线粒体能量产生的抑制。SRL 和 RAD 抑制胞质糖酵解，但不会引起线粒体能量产生的变化。CsA+SRL 抑制三羧酸循环和糖酵解，从而降低细胞补偿 CsA 对线粒体核苷三磷酸合成的负面影响的能力。与在测试浓度下的 SRL 相反，RAD 减少了 CsA 诱导的 ROS 形成，并拮抗了 CsA 对葡萄糖和能量代谢的诱导作用。令人惊讶的是，在 C6 细胞中，SRL 和 RAD 暴露导致高 ROS 浓度，而对细胞代谢没有明显损害。我们的结果表明，SRL 增强了 CsA 诱导的 ROS 形成和脑细胞的负代谢作用，而 RAD 似乎拮抗了 CsA 的作用。然而，当受到研究药物的挑战时，这三种模型显示出不同的代谢反应。与 SRL 不同，RAD 在 C6 神经胶质瘤细胞中增强 ROS 形成，但对正常大鼠脑组织只有较小的影响。
