KATP channels as biomechanical sensors in the regulation of ductus arteriosus tone

项目摘要： 动脉导管（ductus arteriosus，DA）是连接肺和体循环的重要血管分流， 胎儿期的血液循环在出生时，DA必须关闭，以允许新膨胀的肺有足够的灌注。 然而，在某些情况下，DA无法关闭，这种情况称为动脉导管未闭（PDA）。PDA是一个 严重的心血管疾病，影响每500-2000名足月婴儿中的1名， 危重早产儿目前的疗法是有限的，并且具有令人担忧的脱靶效应。加班 在过去的三十年中，已经确定了DA开放的“主要调节剂”，即氧、肾上腺素和肾上腺素。 一氧化氮信号然而，动脉导管未闭的临床难题仍然存在，这表明还有其他未确定的 DA张力的关键调节器。DA经历了一系列独特的生物力学力量， 体内的其他血管。血流模式和血管壁拉伸在血管扩张过程中发生显著变化。 关闭DA的过程。然而，机械感知以前没有被研究作为DA的调节剂 语气 其他人已经确定了一类离子通道，KATP通道，它们可以感知并响应细胞内的变化。 内皮细胞和平滑肌细胞中的生物力学力。我们证明了DA对 生物力学力的变化，并且KATP通道在DA中富集并用于调节张力。 此外，KATP通道基因突变的人患有Cantu综合征， 以PDA为特征。因此，本研究的主要假设是KATP通道调节DA张力 作为一种新型的生物力学传感器，触发DA关闭并在出生时驱动循环适应。我们 将使用在微流控或微流体环境中培养的原代DA内皮细胞和平滑肌细胞来解决这一假设。 拉伸装置。这些实验将阐明DA KATP通道激活的参数 或被特定的血液动力学力抑制。此外，我们将从单个细胞转移到完整的DA， 流动肌电实验，以确定KATP通道的分子机制 总之，这些研究将确定KATP以前未知的作用 此外，通过确定KATP的分子机制， 通道机械感知，这些研究将KATP通道内建立的监管机构的层次结构 的DA张力，并添加一个新的生物力学组件，以目前的范式DA关闭。最后这些 这些研究将使我们能够将我们的发现整合到人类PDA的病理生理学中， 完全了解经常发生在早产儿和Cantu综合征患者中的PDA， 希望开发出更有效的治疗方案。

Project Summary: The ductus arteriosus (DA) is a critical vascular shunt connecting the pulmonary and systemic circulations during fetal life. At birth, the DA must close to allow adequate perfusion of the newly inflated lungs. However, the DA fails to close in some cases, a condition termed patent ductus arteriosus (PDA). PDA is a significant cardiovascular disorder affecting 1 out of every 500-2000 term infants and 30-40% of the most critically ill premature neonates. Current therapies are limited and have worrisome off-target effects. Work over the past thirty years has identified the “master regulators” of DA patency, namely oxygen, prostaglandins, and nitric oxide signaling. However, the clinical conundrum of PDA persists, suggesting there are other unidentified critical regulators of DA tone. The DA experiences a unique set of biomechanical forces that set it apart from all other vessels in the body. Blood flow patterns and vessel wall stretching changes dramatically during the course of DA closure. And yet, mechanosensing has not been previously investigated as a regulator of DA tone. Others have identified a class of ion channels, KATP channels, that sense and respond to changes in biomechanical forces in endothelial and smooth muscle cells. We demonstrated that the DA is sensitive to changes in biomechanical forces and that KATP channels are enriched in the DA and serve to regulate tone. Moreover, humans with mutations in KATP channel genes suffer from Cantu Syndrome, a disorder characterized by PDA. Therefore, the major hypothesis of this proposal is that KATP channels regulate DA tone by acting as novel biomechanical sensors that trigger DA closure and drive circulatory adaptation at birth. We will address this hypothesis using primary DA endothelial and smooth muscle cells cultured in microfluidic or stretch devices. These experiments will elucidate the parameters under which DA KATP channels are activated or inhibited by specific hemodynamic forces. Additionally we will move from individual cells to intact DAs via flow-myography experiments in order to determine the molecular mechanism underlying KATP channel mechanosensing in the DA. Taken together, these studies will identify a previously unknown role for KATP channels as biomechanical sensors in the DA. Moreover, by determining the molecular mechanisms of KATP channel mechanosensing, these studies will place KATP channels within the hierarchy of established regulators of DA tone and add a novel biomechanical component to the current paradigm of DA closure. Finally, these studies will allow us to integrate our findings into the pathophysiology of PDA in humans to gain a more complete understanding of the PDAs that often occur in pre-term infants and Cantu syndrome patients with the hopes of developing more efficient therapeutic options.