Computational discovery of SGK1 inhibitors for the treatment of heart disease

描述（由申请人提供）：心力衰竭（HF）是一种越来越普遍的临床综合征，是各种心肌病过程的最终共同终点，包括心肌梗死、高血压心脏病和遗传性心肌病。心衰与预后不良相关，进行性心室功能障碍和致死性室性心律失常（VA）均可导致严重的死亡率。因此，开发新的治疗方法来改善心功能障碍和纤维化的发展，以及针对致死性心律失常，显然是一个尚未满足的临床需求。血清和糖皮质激素调节激酶-1 （SGK1）是PI3K激酶（PI3K）依赖性激酶，在病理性肥厚和HF中激活，但在生理性肥厚中不激活。我们实验室最近的研究表明，SGK1激活有助于病理性肥大、心脏纤维化和心律失常。相比之下，基因抑制SGK1可减轻生物力学应激后的心力衰竭和纤维化，减少体内心脏缺血再灌注后的缺血损伤，但对基线心功能没有影响。基于这些数据，我们提出SGK1的药理抑制也会减轻不同心脏病理模型的不良重塑，减少心功能障碍、纤维化和心律失常，而在基线时没有不良反应。目前还没有特异性的SGK1抑制剂。我们现在建议使用创新的计算机辅助药物发现（CADD）平台来鉴定和优化SGK1的小分子抑制剂。在Specific Aim 1中，我们将使用基于结构和配体的小分子文库虚拟屏幕来识别抑制SGK1活性的“命中”化合物。这些化合物的活性将使用体外荧光极化激酶测定法进行评估。重要的是，所有小分子“命中”都经过预过滤，以优化ADMET（吸附、分布、代谢、排泄和毒性）指标，从而消除了可能在后期评估中分类的化合物/化学型。在Specific Aim 2中，我们将进一步表征它们在体外心肌细胞中特异性和有效抑制SGK1的能力。使用腺病毒基因转移来创建心肌细胞验证模型，其中SGK1或密切相关的激酶（Akt1， ILK）被特异性激活或抑制，候选抑制剂将被测试其特异性和选择性。最后，在Specific Aim 3中，我们将开始使用野生型小鼠和独特的心脏SGK1激活或抑制的体内小鼠模型来检查已鉴定抑制剂的体内功效和特异性。鉴定特异性和有效的SGK1抑制剂不仅为我们正在进行的SGK1在疾病发病机制中的作用的研究提供了有用的工具，而且还可以为治疗心力衰竭及其并发症的策略提供小分子治疗先导。

DESCRIPTION (provided by applicant): Heart failure (HF) is a clinical syndrome of growing prevalence and is the final common endpoint of a variety of cardiomyopathic processes including myocardial infarction, hypertensive heart disease, and inherited cardiomyopathies. HF is associated with a poor prognosis, with significant mortality attributed to both progressive ventricular dysfunction and lethal ventricular arrhythmias (VA). Hence there is a clear unmet clinical need to develop novel therapies that can ameliorate the development of cardiac dysfunction and fibrosis as well as target lethal arrhythmias. Serum- and glucocorticoid-regulated kinase-1 (SGK1) is a PI3-kinase (PI3K)-dependent kinase that is activated in pathological hypertrophy and HF but not in physiological hypertrophy. Recent work from our laboratory suggests that SGK1 activation contributes to pathological hypertrophy, cardiac fibrosis, and arrhythmia. In contrast, genetic inhibition of SGK1 mitigates heart failure and fibrosis after biomechanical stress and reduces ischemic injury after in vivo cardiac ischemia-reperfusion, but has no effect on baseline cardiac function. On the basis of these data, we propose that pharmacological inhibition of SGK1 would also mitigate adverse remodeling in different models of cardiac pathology, reducing cardiac dysfunction, fibrosis and arrhythmia without having an adverse effect at baseline. Currently there are no specific inhibitors of SGK1 available. We now propose to use an innovative computer aided drug discovery (CADD) platform to identify and optimize small molecule inhibitors of SGK1. In Specific Aim 1, we will use structure- and ligand-based virtual screens of small molecule libraries to identify "hit" compounds that inhibit SGK1 activity. The activity of these compounds will be evaluated using an in vitro fluorescence polarization kinase assay. Importantly, all small molecule "hits" are pre-filtered for optimized ADMET (adsorption, distribution, metabolism, excression and toxicity) metrics, which eliminates compounds/chemotypes that are likely to be triaged in late stage evaluation. In Specific Aim 2, we will further characterize the top candidates for their ability to specifically and effectively inhibit SGK1 in vitro in cardiomyocytes. Using adenoviral gene transfer to create cardiomyocyte validation models in which SGK1 or closely related kinases (Akt1, ILK) are specifically activated or inhibited, the candidate inhibitors will be tested for their specificity and selectivity. Finally, in Specific Aim 3, we will begin to examine the in vivo efficacy and specificity of identified inhibitors using both wildtype mice and unique in vivo mouse models of cardiac SGK1 activation or inhibition. The identification of specific and effective inhibitors for SGK1 would not only provide us with useful tools for our ongoing investigation of SGK1's role in disease pathogenesis but could also provide a small molecule therapeutic lead for strategies treating heart failure and its complications. PUBLIC HEALTH RELEVANCE: Heart failure is a clinical syndrome of growing prevalence and a major cause of morbidity and mortality throughout the world. Hence there is a clear unmet clinical need to develop novel therapies that can ameliorate this important clinical condition. Studies from our group and others using genetically engineered animal models have suggested that inhibition of the kinase, SGK1, could have significant benefits in heart failure and its sequelae. Although there are currently no known pharmacological inhibitors of SGK1, kinases have been considered good targets for drug development in other settings. In this project, we propose to use an innovative computer aided drug discovery approach to identify inhibitors of SGK1. Top candidates will be characterized for their ability to specifically and effectively inhibit SGK1 in isolated heart muscle cells and in hearts of animals. The identification of specific and effective inhibitors for SGK1 would not only yield useful tools for ongoing investigation of disease mechanisms but could also provide a foundation for novel therapeutic approaches to heart failure and its complications.