Pharmacological Validation of Vascular KATP Channels for Modulating Ductus Arteriosus Tone

项目摘要 动脉导管（DA）是连接主动脉和肺动脉的重要胎儿动脉， 血液从子宫内发育的肺中流出 . 出生时的循环适应需要快速收缩 DA以促进新膨胀的肺的适当灌注。新生儿DA（PDA）的持续通畅是一种 严重的临床问题，目前可用的治疗方法无法有效管理。药理学基础 PDA治疗剂非特异性靶向前列腺素途径，对其他前列腺素途径具有令人担忧的脱靶效应。 血管床，并且在大约30%的患者中无效。虽然外科结扎和基于导管的 虽然闭合是有效的替代方法，但这些机械方法也有其自身的风险和局限性。 因此，非常需要鉴定和严格验证用于操纵的新型药物靶标， 检察官的语气。一个新兴的身体的生理和遗传数据，从我们的小组和其他人已经暗示 血管ATP调节的钾（KATP）通道作为调节DA张力的新药物靶点。具体地说， 我们首次发现KATP通道由成孔Kir6.1和调节性SUR 2B组成， 亚基在PDA的平滑肌细胞中高度富集，并调节DA张力以响应 药理学调节不幸的是，缺乏特异性Kir6.1/SUR 2B抑制剂（和激活剂）， 排除了对DA KATP通道治疗PDA的治疗潜力的严格评估。在这 多PI合作，将受益于钾通道药物发现方面的互补专业知识 (Drs.丹顿/Lindsley）和DA生理学和药理学（谢尔顿博士），我们建议采用高- 通量筛选（HTS）和药物化学，以开发血管特异性KATP的广泛“工具包 用于验证Kir6.1/SUR 2B通道在体外和体内调节DA张力的通道调节剂。在目标1中， 我们将采用一种经过充分验证的HTS检测方法，对约110，000种小分子进行检测， Kir6.1/SUR 2B调节剂。在目标2中，我们将使用药物化学来优化先导化合物的选择性 和效力并确定化合物代谢和药代动力学性质。在目标3中，我们将评估 使用离体血管肌造影术观察先导化合物调节小鼠和人DA张力的功效 测定和PDA的体内小鼠模型。这些目标的成功实现将产生关键的 需要用于调节DA张力的工具化合物，并验证Kir6.1/SUR 2B通道作为新的治疗药物 治疗PDA的目标。

PROJECT SUMMARY The ductus arteriosus (DA) is an essential fetal artery connecting the aorta and pulmonary artery, which shunts blood away from the developing lungs in utero . Circulatory adaptation at birth requires rapid constriction of the DA to facilitate proper perfusion of the newly inflated lungs. Persistent patency of the neonatal DA (PDA) is a significant clinical problem that is inefficiently managed with currently available therapies. Pharmacology-based PDA therapeutics non-specifically target the prostaglandin pathway, have worrisome off target effects on other vascular beds, and are ineffective in approximately 30% of patients. While surgical ligation and catheter-based closure are effective alternatives, these mechanical approaches come with their own risks and limitations. Consequently, there is a significant need to identify and rigorously validate novel drug targets for manipulating DA tone. An emerging body of physiological and genetic data from our group and others has implicated vascular ATP-regulated potassium (KATP) channels as novel drug targets for regulating DA tone. Specifically, we show here for the first time that KATP channels comprised of pore-forming Kir6.1 and regulatory SUR2B subunits are highly enriched in smooth muscle cells of the PDA and regulate DA tone in response to pharmacological modulation. Unfortunately, the lack of specific Kir6.1/SUR2B inhibitors (and activators) has precluded a rigorous assessment of the therapeutic potential of DA KATP channels for treating PDA. In this multi-PI collaboration, which will benefit from complementary expertise in potassium channel drug discovery (Drs. Denton/Lindsley) and DA physiology and pharmacology (Dr. Shelton), we propose to employ high- throughput screening (HTS) and medicinal chemistry to develop an extensive “tool kit” of vascular-specific KATP channel modulators for validating Kir6.1/SUR2B channels for regulating DA tone in vitro and in vivo. In Aim 1, we will employ a fully validated HTS assay to interrogate ~110,000 small molecules for potent and selective Kir6.1/SUR2B modulators. In Aim 2, we will use medicinal chemistry to optimize lead compounds for selectivity and potency and determine compound metabolism and pharmacokinetic properties. In Aim 3, we will evaluate the efficacy of lead compounds to regulate mouse and human DA tone using isolated vessel myography assays and in vivo mouse models of PDA. The successful completion of these aims will generate critically needed tool compounds for modulating DA tone and validate Kir6.1/SUR2B channels as novel therapeutic targets for treating PDA.