Does UCP2/3 Overexpression Mimic Caloric Restriction?

描述(由申请人提供)：卡路里限制(CR)扩展平均值和 通过未描述的机制实现最大寿命。一种假设是 CR通过减少氧化应激[产生和/或损害 活性氧种(ROS)]。支持这一点的是数据显示CR 减少氧化应激/损伤；但氧化之间没有因果关系 压力和寿命已被证明，部分原因是缺乏适当的 动物模型。我们有过多表达线粒体的转基因小鼠 解偶联蛋白(UCP)-2和3，降低质子动力和 可能导致线粒体产生较少的ROS。在6个月大的时候 转基因，UCP2高表达的大脑区域脂质较少 过氧化和神经炎症比野生型要好；而在神经细胞 创伤，转基因显示较少的细胞凋亡。相比之下，UCP3基因敲除 肌肉线粒体产生更多的ROS，表现出更多的氧化损伤。 这些数据强烈表明，在临时喂养的动物中，UCP2/3的表达增加 小鼠在氧化应激方面模仿CR。我们将通过以下方式进行测试 测定骨骼组织中ROS的生成、脂质和蛋白质损伤以及细胞凋亡 肌肉(UCP3表达)、下丘脑(UCP2表达)和肝脏(否 UCP2或UCP3的显著表达)在4岁以上。我们还将 确定转基因小鼠是否像CR小鼠一样活得更长。虽然我们假设 这是一个相反的发现(中值/最大值没有扩展 尽管氧化损伤较少，但转基因生物的寿命)会反对 这两种现象之间的因果联系。我们将评估UCP2/3转基因， UCP2和UCP3基因敲除，野生型随机喂养，CR野生型小鼠 中位/最长寿命、线粒体ROS、基因表达模式(通过 微阵列)、氧化损伤、细胞凋亡/细胞死亡和神经炎症。 如果UCP2/3的表达增加模拟热量限制，变化应该 在性质上与CR野生型小鼠相似，但在 淘汰赛的方向相反。最后，我们假设生命-- UCP2/3表达增加的延伸效应不会减少 在总能量消耗或循环葡萄糖方面(即两者都不是 对延长寿命至关重要)。我们的数据将决定是否更多地表达 UCP2/3模拟了CR的作用，并将增加我们对机制的理解 有可能延长中位数和最长寿命的产品。

DESCRIPTION (provided by applicant): Caloric restriction (CR) extends mean and maximum life span via mechanisms that are not delineated. One hypothesis is that CR acts by reducing oxidative stress [generation of and/or damage from reactive oxygen species (ROS)]. Supporting this are data showing that CR reduces oxidative stress/damage; but no causal relationship between oxidative stress and life span has been proven, due in part to lack of an appropriate animal model. We have transgenic mice that over express mitochondrial uncoupling proteins (UCP)-2 and 3, decreasing protonmotive force and presumably resulting in mitochondria that generate less ROS. In 6-month-old transgenics, brain areas with high UCP2 expression have less lipid peroxidation and neural inflammation than do the wild type; and after a neural trauma, transgenics show less apoptosis. In contrast, UCP3 knockouts have muscle mitochondria that generate more ROS and exhibit more oxidative damage. These data suggest strongly that elevated UCP2/3 expression in ad libitum-fed mice mimics CR with respect to oxidative stress. We will test this by measuring ROS generation, lipid & protein damage, and apoptosis in skeletal muscle (UCP3 expression), hypothalamus (UCP2 expression), and liver (no significant UCP2 or 3 expression) at 4 ages over the life span. We will also determine if transgenics live longer as do CR mice. While we hypothesize that this is the case, a finding to the contrary (no extension of median/maximum life span in transgenics despite less oxidative damage) would argue against causal links between the two phenomena. We will evaluate UCP2/3 transgenics, UCP2 & UCP3 knockouts, wild type fed ad lib, and CR wild type mice for median/maximum life span, mitochondrial ROS, gene expression patterns (via microarrays), oxidative damage, apoptosis/cell death, and neural inflammation. If increased expression of UCP2/3 mimics caloric restriction, changes should be qualitatively similar to those in CR wild type mice, with changes in the opposite direction for the knockouts. Finally, we hypothesize that the life- extending effects of increased UCP2/3 expression will occur without decreases in total energy expenditure or circulating glucose (i.e., that neither is critical to life extension). Our data will determine if greater expression of UCP2/3 mimics effects of CR and will increase our understanding of mechanisms that have potential to increase median and maximum life span.