Compromised function of a glial glucose transporter in aging and Alzheimer's disease

总结 衰老是阿尔茨海默病（AD）最强大的风险因素，它有助于2型糖尿病的发病率。 糖尿病（T2 D）。衰老也与大脑对葡萄糖的使用减少有关，葡萄糖是大脑最重要的代谢物。 重要的燃料。星形胶质细胞在将葡萄糖从血流运送到需要的地方方面起着关键作用。 脑组织深处的神经元活动单位。我们发现了一个关键的葡萄糖转运缺陷的证据 在AD和经遗传修饰以复制AD的某些方面的小鼠系中的星形胶质细胞分子。这 过量产生β-淀粉样肽（Aβ）的小鼠系表现出循环葡萄糖调节异常， 大脑葡萄糖利用率下降这些影响与空间记忆测试中的不良表现相关。 进一步模仿人类AD，小鼠在没有肥胖、高血糖、 食欲不振、体力活动改变、胰腺异常或胰岛素抵抗。在一起， 这些发现激发了一种假设，即即使没有大脑老化，Aβ的水平也会开始上升。 坦率的AD，扰乱了星形胶质细胞将外周葡萄糖带到神经元的能力，神经元需要葡萄糖。 与记忆和其他功能相关的神经活动增加。这个想法将通过 对衰老小鼠和人脑中葡萄糖转运蛋白的状态和功能的研究，沿着 正常老化、AD和T2 D之间的比较。通过对老鼠进行基因改造，我们将调节 最重要的星形胶质细胞葡萄糖转运蛋白的水平，以确定它是否i）足以引起 中断的葡萄糖输送和记忆缺陷，和ii）必要的这些问题的介绍， AD模型因此，这些研究探索了一个关于能源利用的特定因素的新假设， 衰老的大脑及其与年龄相关的认知障碍的联系。因此，该项目可以提供 治疗干预的创新战略。

SUMMARY Aging is the most powerful risk factor for Alzheimer’s disease (AD), and it contributes to the odds of type-2 diabetes mellitus (T2D) as well. Aging is also associated with a decline in the brain’s use of glucose, its most important fuel. Astrocytes play a key role in shuttling glucose from the bloodstream to where it is needed by the neuronal units of activity deeper in the brain tissue. We find evidence of a defect in a key glucose transport molecule of astrocytes in AD and in a mouse line genetically modified to reproduce some aspects of AD. This mouse line, overproducing the β-amyloid peptide (Aβ), exhibits dysregulation of circulating glucose, as well as a decline in brain glucose use. These effects are correlated with poor performance in a test of spatial memory. Further mimicking human AD, the mice show these problems in the absence of obesity, hyperglycemia, disruption of appetite, changes in physical activity, pancreatic abnormality, or insulin resistance. Together, these findings inspire the hypothesis that Aβ, the levels of which begin to rise in the aging brain even without frank AD, perturbs the ability of astrocytes to bring peripheral glucose to neurons, where it is needed for the increased neurological activity associated with memory and other functions. This idea will be tested through studies of the status and function of glucose transport proteins in aging mouse and human brains, along with comparisons between normal aging, AD, and T2D. Through genetic modification of mice, we will modulate the levels of the most important astrocytic glucose transporter to determine if it is i) sufficient to bring about interrupted glucose delivery and memory deficits, and ii) necessary for the presentation of these problems in an AD model. These studies thus explore a novel hypothesis about a specific element of energy utilization in the aging brain and its connection to age-related cognitive impairment. As such, the project may provide innovative strategies for therapeutic intervention.