Pharmacological Validation of Vascular KATP Channels for Modulating Ductus Arteriosus Tone

项目总结 动脉导管(DA)是连接主动脉和肺动脉的重要胎儿动脉。 子宫内血液从发育中的肺中排出 。 出生时的循环适应需要快速收缩 DA以促进新充气的肺的适当灌流。新生儿动脉导管未闭(PDA)持续开放是一种 严重的临床问题，目前可用的治疗方法处理不力。以药理学为基础 PDA疗法非特异性地针对前列腺素途径，对其他 血管床，在大约30%的患者中无效。同时手术结扎和以导管为基础 关闭是有效的替代方案，这些机械方法都有其自身的风险和局限性。 因此，非常需要识别和严格验证用于操作的新的药物靶点 我的语气。来自我们小组和其他人的一组新的生理和基因数据表明 血管ATP调节钾通道作为调节DA张力的新药物靶点。具体来说， 我们首次展示了KATP通道由成孔的Kir6.1和调节的SUR2B组成 PDA的平滑肌细胞中的亚基高度丰富，并调节DA张力 药理调节。不幸的是，缺乏特定的Kir6.1/SUR2B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 (丹顿/林德斯利博士)和DA生理学和药理学(谢尔顿博士)，我们建议使用高- 吞吐量筛选(HTS)和药物化学开发广泛的血管特异性KATP“工具包” 通道调节剂用于在体内外验证Kir6.1/SUR2B调节DA音调的通道。在目标1中， 我们将使用一种完全有效的HTS测试来讯问约110,000个小分子，以获得高效和选择性 Kir6.1/SUR2B调制器。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，并确定化合物的代谢和药代动力学性质。在目标3中，我们将评估 分离血管造影术观察先导化合物对小鼠和人DA张力的调节作用 PDA的检测和体内小鼠模型。这些目标的成功实现将产生至关重要的影响 调节DA音调所需的工具化合物和验证Kir6.1/SUR2B通道作为新的治疗药物 治疗PDA的靶点。

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.