Functionally probing hSGLT2 in diabetes treatment and glucose homeostasis

描述(申请人提供)：糖尿病是21世纪发达国家面临的巨大健康挑战之一，对社会和个人都造成了巨大的代价。因此，目前有很大的兴趣寻找方法，以减少这类以糖稳态失调为特征的疾病的发病率和死亡率。其中一个方向是开发药物，通过人类钠/葡萄糖共转运蛋白2(HSGLT2)来钝化肾脏对糖的重新吸收；虽然有几十种药物正在研发或早期临床试验中，但对hSGLT2的了解很少。它与其特征良好的肠道同源基因hSGLTI相似吗？它如何使用钠梯度来驱动肾脏对糖的重新摄取？哪些分子与hSGLT2结合并被hSGLT2运输，哪些在结合和解离之间切换而不被运输？HSGLT2的全球表达(即在整个身体)如何在葡萄糖稳态中发挥作用？考虑到这些以及更多的相关问题，本研究的目标如下：具体目标1：建立hSGLT2的动力学模型。通过稳态和稳态前分析的新方法(通过HEK293细胞的膜片钳实验)，我们将了解这种低亲和力、高容量转运体的关键步骤和运输特性。具体目标2：确定hSGLT2的底物、激动剂和拮抗剂。通过一个工作的动力学模型，各种分子的活性将在这项研究中得到表征，这些分子的版本是针对hSGLT2的药物治疗的基础。随着hSGLT2底物特异性的进一步完善，我预计这项研究将导致设计和测试hSGLT2特异性探针，用于正电子发射断层扫描(PET)的成像。通过这一点，我们将了解阻断hSGLT2转运的全球影响，我们将能够从功能上想象调节和失调的葡萄糖稳态。*糖尿病是一种流行病，对研究它的科学家和治疗它的医生都构成了独特的挑战。最近的治疗发展旨在通过人钠葡萄糖协同转运蛋白2(HSGLT2)靶向肾脏重新吸收葡萄糖，如果被阻断，有助于控制血糖水平。为了更好地确定靶向hSGLT2的药物的疗效和副作用，以及通过未来的功能成像研究确定hSGLT2的S对血糖水平的真实影响，本工作集中在对该转运体的表征上。

DESCRIPTION (provided by applicant): Diabetes mellitus is one of the great health challenges facing the developed world in the 21st century, with monumental costs levied both to society and the individual. As such, there currently is great interest in finding ways to reduce the morbidity and mortality due to this group of disorders characterized by dysregulated glucose homeostasis. One such direction aims to develop pharmaceutical agents that blunt sugar reabsorption in the kidneys via the human sodium/glucose cotransporter 2 (hSGLT2); and while several dozen drugs are in either research and development or early stage clinical trials, little remains known about hSGLT2. Is it similar to its well-characterized intestinal counterpart hSGLTI ? How does it use a sodium gradient to drive renal reuptake of sugar against a gradient? Which molecules bind to and are transported by hSGLT2 and which toggle between binding and dissociating without being transported? How does global expression (i.e. throughout the entire body) of hSGLT2 play a role in glucose homeostasis? With these, and many more related questions in mind, this study's aims are as follows: Specific Aim 1: Establish a kinetic model for hSGLT2. With novel methods of both steady-state and presteady-state analyses (with patch clamp experiments in HEK293 cells), we will understand key steps and properties of transport by this proposed low-affinity, high-capacity transporter. Specific Aim 2: Identify substrates, agonists, antagonists for hSGLT2. With a working kinetic model, the activity of a variety of molecules - versions of which are the basis of pharmacotherapy aimed at hSGLT2 - will be characterized in this study. As the substrate specificity of hSGLT2 is further refined, I anticipate this research leading to the design and testing of hSGLT2-specific probes for imagining with positron emission tomography (PET). Through this, we will understand the global impact of blocking hSGLT2 transport, and we will be able to functionally image both regulated and dysregulated glucose homeostasis. *A disease of epidemic proportions, diabetes mellitus poses unique challenges to both the scientists who research and physicians who treat it. Recent therapeutic development aims to target the kidneys' reabsorption of glucose through the human sodium glucose cotransporter 2 (hSGLT2) which, if blocked, helps to control blood glucose levels. This work focuses on characterizing this transporter in order to better define efficacy and side effects of drugs targeting hSGLT2, as well as defining hSGLT2's true impact on blood glucose levels through future studies in functional imaging.