Functionally probing hSGLT2 in diabetes treatment and glucose homeostasis

描述（由申请人提供）：糖尿病是21世纪发达国家面临的重大健康挑战之一，给社会和个人带来巨大的成本。因此，目前人们对寻找降低由于这组以葡萄糖稳态失调为特征的疾病引起的发病率和死亡率的方法非常感兴趣。一个这样的方向旨在开发通过人钠/葡萄糖协同转运蛋白2（hSGLT 2）减弱肾脏中糖重吸收的药剂;虽然几十种药物处于研发或早期临床试验中，但对hSGLT 2知之甚少。它与其特征明确的肠道对应物hSGLTI相似吗？它是如何利用钠梯度来驱动肾脏对糖的再摄取的？哪些分子与hSGLT 2结合并被其转运，哪些分子在结合和解离之间切换而不被转运？hSGLT 2的整体表达（即整个身体）如何在葡萄糖稳态中发挥作用？考虑到这些以及更多相关问题，本研究的目标如下：具体目标1：建立hSGLT 2的动力学模型。通过稳态和稳态前分析的新方法（在HEK 293细胞中进行膜片钳实验），我们将了解这种低亲和力，高容量转运蛋白的关键步骤和转运特性。具体目标2：鉴定hSGLT 2的底物、激动剂、拮抗剂。利用工作动力学模型，各种分子的活性-其版本是针对hSGLT 2的药物治疗的基础-将在本研究中表征。随着hSGLT 2的底物特异性的进一步完善，我预计这项研究将导致hSGLT 2特异性探针的设计和测试，用于正电子发射断层扫描（PET）成像。通过这一点，我们将了解阻断hSGLT 2转运的全球影响，我们将能够在功能上成像调节和失调的葡萄糖稳态。* 糖尿病是一种流行病，对研究糖尿病的科学家和治疗糖尿病的医生都提出了独特的挑战。最近的治疗发展旨在通过人钠葡萄糖协同转运蛋白2（hSGLT 2）靶向肾脏对葡萄糖的重吸收，如果被阻断，有助于控制血糖水平。这项工作的重点是表征这种转运蛋白，以更好地确定靶向hSGLT 2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hSGLT 2对血糖水平的真正影响。

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.