Development of inhibitors of AMP Deaminase Isoform 2 as a Mechanism for Treating

描述(申请人提供)：我们的申请属于“将基础科学发现转化为新的更好的治疗方法”这一主题。该项目的目标是开发第一种选择性单磷酸腺苷脱氨酶-2(AMPD2)抑制剂，我们相信这将为代谢综合征疾病的治疗提供一种重要的新方法。AMPD2是肝脏中存在的主要AMP亚型，它驱动AMP与肌苷一磷酸(IMP)及其下游产物如尿酸的反应。我们的初步数据表明，AMPD2是将哺乳动物从脂肪利用切换到脂肪积累的关键酶，这一途径的激活会导致AMP激酶的抑制，AMP激酶是指导脂肪利用和脂肪合成减少的关键酶。我们有间接证据表明，当冬眠动物进入昏迷状态时，AMPD途径被下调，从而允许它们激活AMP激酶并启动脂肪降解，以此作为利用储存能量的一种手段。相比之下，人类似乎因为两种机制而“锁定”脂肪积累：第一，进化提供了一种人类尿酸酶突变，导致高尿酸，我们发现这种突变进一步上调了AMPD2；第二，因为人类饮食中添加糖中果糖的显著摄取，这也刺激了AMPD2，同时提供了底物。抑制AMPD2似乎是预防和治疗代谢综合征、肥胖、糖尿病和心血管疾病的一种新机制。在这项提案中，我们将完成概念证明(具体目标1)，并开发第一类针对推动这一过程的AMPD关键亚型(AMPD2)的新药(具体目标2)。目的1评价AMPD2在诱发代谢综合征中的作用。这将包括细胞培养研究(使用siRNA或产生的阻断AMPD2活性的药物)和动物研究(通过创造转基因和敲除AMPD2的小鼠)，在正常条件下和在给予高果糖或高脂肪饮食之后。我们还将评估从AIM 2产生的AMPD2抑制剂的作用，因为它与细胞培养和动物模型中的有效性、特异性和毒性有关。AIM 2将专注于药物的发现和开发，并将使用三种方法：a)基于已知的非选择性抑制剂考福霉素咪唑二氮环的分子建模辅助设计和优化选择性AMPD2抑制剂；b)在存在或不存在抑制剂的情况下，基于人AMPD2的第一晶体结构(将由科罗拉多大学X射线核心设施获得)进行分子建模；以及c)高通量筛选AMPD2的新原型选择性抑制剂。通过将约翰逊博士的基础科学实验室的专业知识与AmidAerus公司经验丰富的药物设计团队相结合，我们预计将开发出第一种AMPD2抑制剂，将在3年期末准备好进行第一阶段试验。 公共卫生相关性：确定肥胖和代谢综合征病因学的新途径，以及潜在的新疗法，是这项应用的主题。具体地说，我们已经确定了单磷酸腺苷脱氨酶-2(AMPD2)在驱动导致脂肪堆积和胰岛素抵抗的关键过程中的作用，在这一应用中，我们提议研究开发第一个AMPD2抑制剂，我们预计这将为预防和治疗肥胖症、高血压、代谢综合征和糖尿病提供一个重要的新途径。

DESCRIPTION (provided by applicant): Our application belongs to the theme, "Translating Basic Science Discoveries into New and Better Treatments". The goal of the project is to develop the first selective adenosine monophosphate deaminase- 2 (AMPD2) inhibitor, which we believe will offer an important new method of treatment for diseases of metabolic syndrome. AMPD2 is the predominant AMP isoform that is present in liver and drives the reaction of AMP to IMP (inosine monophosphate) and downstream products such as uric acid. Our preliminary data suggests that AMPD2 is the key enzyme that switches mammals from fat utilizing to fat accumulating, and that activation of this pathway results in the inhibition of AMP kinase, a key enzyme that directs fat utilization and a reduction in fat synthesis. We have indirect evidence that the AMPD pathway is down-regulated by hibernating animals as they enter torpor, thus allowing them to activate AMP kinase and initiate fat degradation as a means to utilize stored energy. In contrast, humans appear to be "locked in" to be fat accumulating due to two mechanisms: first, evolution has provided a human mutation in uricase that results in high uric acid, which we have found further up-regulates AMPD2, and second, because of the marked intake of fructose present in added sugars of the human diet that also stimulates AMPD2 along with providing substrate. Inhibition of AMPD2 appears to be a novel mechanism for preventing and treating metabolic syndrome, obesity, diabetes and cardiovascular disease. In this proposal we will both complete a proof of concept (Specific Aim 1) and develop the first of a new class of drugs that will target the key isoform of AMPD that is driving this process (AMPD2) (Specific Aim 2). Aim 1 will evaluate the role for AMPD2 in inducing metabolic syndrome. This will consist of cell culture studies (using siRNA or drugs generated that block AMPD2 activity) and animal studies (by creating transgenic and knockout AMPD2 mice) under both normal conditions and following the administration of a high fructose or high fat diet. We will also evaluate the role of AMPD2 inhibitors generated from Aim 2 as it relates to efficacy, specificity and toxicity in cell culture and animal models. Aim 2 will focus on drug discovery and development and will use three approaches; a) molecular modeling aided design and optimization of a selective AMPD2 inhibitor based on modification of the imidazodiazepine ring of coformycin, a known but nonselective inhibitor; b) molecular modeling based on the first crystal structure of human AMPD2 ( to be obtained with the University of Colorado X-ray Core Facility) in the presence or absence of inhibitors; and, c) by high- throughput screening for novel prototype selective inhibitors of AMPD2. By combining the expertise of the basic science laboratory of Dr. Johnson with the highly experienced drug design team from Amidaerus, we expect to develop the first AMPD2 inhibitor that will be ready for Phase I trials at the end of the 3 year period. PUBLIC HEALTH RELEVANCE: Identifying novel pathways for the etiology of obesity and metabolic syndrome, and potentially new therapies, is the topic of this application. Specifically, we have identified a role for adenosine monophosphate deaminase-2 (AMPD2) in driving key processes that lead to fat accumulation and insulin resistance, and in this application we propose studies to develop the first AMPD2 inhibitor which we predict will provide a major new approach for preventing and treating obesity, hypertension, metabolic syndrome, and diabetes.