Amyloid beta peptides and type-2 diabetes sequelae synergistically inhibit insulin signaling and trafficking at the blood brain barrier

项目总结 2型糖尿病后遗症损害脑微血管并加重阿尔茨海默病 以亚生理胰岛素水平和受损为特征的脑胰岛素抵抗的病理学 大脑中的胰岛素信号。相反，血浆中积累的可溶性淀粉样β蛋白(Saβ)多肽 而大脑在阿尔茨海默病进展过程中加重了T2 DM的影响，加重了脑内胰岛素 抵抗。迫切需要确定T2 DM后遗症和Saβ暴露如何抑制胰岛素传递 并加强大脑对胰岛素的抵抗。长期目标是阐明脑血管和 代谢对阿尔茨海默病的贡献和促进新疗法的发展 干预措施。本应用的总体目标是确定T2 DM后遗症的综合影响 和Saβ对胰岛素向大脑传递的影响，并确定潜在的细胞和分子机制。这个 中心假设是T2 DM后遗症和Saβ多肽扰乱了胰岛素信号转导/转运 脑血管内皮细胞[称为血脑屏障(BBB)]并减少胰岛素向 大脑。还假设，这些影响会因两种疾病之间的病理协同作用而进一步加剧。 T2 DM后遗症和Saβ。提出这项研究的理由是机械地理解如何 SAβ暴露和T2 DM后遗症扰乱大脑胰岛素供应将使我们能够开发新的治疗方法 应对阿尔茨海默病和2型糖尿病患者脑内胰岛素抵抗的策略。在初步数据的指导下， 提出了以下三个具体目标：1)确定T2 DM后遗症对胰岛素的影响 血脑屏障的贩运/信号；2)确定Saβ单独和与T2 DM后遗症一起的影响 关于血脑屏障的胰岛素转运/信号；以及3)确定血脑屏障的胰岛素转运途径， 与β暴露和胰岛素信号受损有关。在第一和第二目标下，动态SPECT/CT成像 将用于表征2型糖尿病和糖尿病小鼠血脑屏障的胰岛素摄取动力学。 阿尔茨海默氏症后遗症。此外，血脑屏障胰岛素信号的失调将被反向捕捉到。 相蛋白阵列。对于第三个目的，将使用流式细胞术和TIRF显微镜来确定 Saβ±胰岛素信号转导抑制剂对血脑屏障单层胰岛素转运的影响拟议的研究 它具有潜在的创新性，因为它使用了动态成像方法与定量建模相结合 捕捉T2 DM和阿尔茨海默病小鼠血脑屏障胰岛素转运动力学变化的技术 模特们。这项拟议的研究具有重要意义，因为它预计将具有广泛的翻译意义 改变现有药物的用途以治疗脑胰岛素抵抗和确定候选靶点的重要性 发现新药。工作完成后，预计产生的新知识将具有 通过促进确定抗击大脑的新治疗策略产生重要的积极影响 阿尔茨海默病合并2型糖尿病患者的胰岛素抵抗

PROJECT SUMMARY Type-2 diabetes mellitus (T2DM) sequelae damage the cerebral microvasculature and augment Alzheimer's pathology by inducing brain insulin resistance characterized by sub-physiological insulin levels and impaired insulin-signaling in the brain. Conversely, soluble amyloid beta (sAβ) peptides that accumulate in the plasma and brain during Alzheimer's progression exacerbate the impact of T2DM and aggravate brain insulin resistance. A critical need exists to identify how T2DM sequelae and sAβ exposure inhibit insulin delivery to the brain and intensify brain insulin resistance. The long-term goal is to elucidate cerebrovascular and metabolic contributions to Alzheimer's disease and facilitate the development of novel therapeutic interventions. The overall objective in this application is to determine the combined effects of T2DM sequelae and sAβ on insulin delivery to the brain and to identify the underlying cellular and molecular mechanisms. The central hypothesis is that T2DM sequelae and sAβ peptides perturb insulin signaling/trafficking at the cerebrovascular endothelium [referred to as the blood brain barrier (BBB)] and reduce insulin delivery to the brain. It is also hypothesized that these effects are further aggravated by the pathological synergism between T2DM sequelae and sAβ. The rationale for the proposed research is that a mechanistic understanding of how sAβ exposure and T2DM sequelae disrupt brain insulin delivery will allow us to develop novel therapeutic strategies to address brain insulin resistance in Alzheimer's disease and T2DM. Guided by preliminary data, the following three specific aims are proposed: 1) Determine the effect of T2DM sequelae on insulin trafficking/signaling at the BBB; 2) Determine the effects of sAβ alone and in conjunction with T2DM sequelae on insulin trafficking/signaling at the BBB; and 3) Identify insulin trafficking pathways at the BBB, vulnerable to sAβ exposure and impaired insulin signaling. Under the first and second aims, dynamic SPECT/CT imaging will be used to characterize insulin uptake kinetics at the BBB in mouse models that exhibit T2DM and Alzheimer's sequelae. Moreover, the dysregulation in insulin signaling at the BBB will be captured by reverse phase protein arrays. For the third aim, flow cytometry and TIRF microscopy will be used to determine the effects of sAβ ± insulin signaling inhibitors on insulin transcytosis in BBB monolayers. The proposed research is potentially innovative because it employs dynamic imaging methods coupled with quantitative modeling techniques to capture changes in insulin trafficking kinetics at the BBB in T2DM and Alzheimer's mouse models. The proposed research is significant because the contribution it is expected to have broad translational importance in repurposing existing drugs to treat brain insulin resistance and in identifying candidate targets to discover novel drugs. Upon completion of the work, the new knowledge generated is expected to have an important positive impact by facilitating the identification of novel therapeutic strategies to combat brain insulin resistance in Alzheimer's patients with T2DM.