Altered Lymphatic Function and Development in Congenital Heart Disease

项目总结/摘要 淋巴结构和功能的异常越来越被认为是疾病的重要来源 in a variety品种of disease疾病state状态.例如，与先天性心脏病相关的淋巴异常 (CHD)导致肺血流量（PBF）增加，包括先天性或获得性乳糜胸， 免疫畸变重要的是，越来越多的人认识到，淋巴异常不仅是 与多种肺部疾病相关，但参与其发病机制。最近认识到， 异常呼吸功能障碍通常在心脏矫正后持续数年，是一个独立的危险因素 成人CHD患者的死亡率增加了新的紧迫性，以更好地了解潜在的淋巴结转移。 CHD的病理生物学，迄今为止在很大程度上仍然未知。我们以前使用过临床相关的 PBF（分流）增加的CHD大型动物模型， 胸导管和原代淋巴管内皮细胞（LEC）培养，以证明慢性增加的PBF 以及由此引起的淋巴流量的增加与以下有关：1）异常的肺淋巴流量， 结构; 2）增加线粒体活性氧（mtROS）驱动的缺氧诱导因子-1（HIF-1 α） （3）KLF-1依赖性活化和代谢重编程，以支持细胞增殖;和 减少一氧化氮（NO）信号传导。在这个更新应用程序中，我们将测试我们的新假设， 在PBF增加的情况下，机械感觉通道Piezo 1在感知 淋巴流动，触发下游内皮素-1（ET-1）和mtROS驱动的HIF-1a活性增加。这 导致NO生物利用度降低，随后出现淋巴功能障碍，从而导致持续性 即使在心脏缺损修复后，呼吸力学也异常。为了支持这一假设， 我们目前的初步证据表明：1）增加淋巴管内皮Piezo 1，ET-1，RhoA， 分流LEC中的mtROS; 2）对照LEC中HIF-1 α的Piezo 1-、ET-1-和mtROS依赖性增加; 3）分流LEC中的 羔羊具有异常的呼吸力学和淋巴管内皮功能障碍，这些障碍在闭合后持续存在 尽管血流动力学正常化，但分流术的治疗仍然有效，以及4）使用靶向抗氧化剂治疗 （mitoquinone，MitoQ）在体外逆转HIF-1 α介导的分流LEC表型，并使肺组织正常化。 淋巴结构和功能。这一整体假设将在三个相互关联的测试，但 独立的机械目标，利用综合生理，细胞和分子实验。这些 转化和靶向研究包括：1）全动物血流动力学生理学研究，高级 CT/MR成像和复杂的肺功能测试，2）离体胸导管反应性研究，和3） 在LEC中的转录和代谢研究。更深入地了解所研究的机制可能会导致 在CHD和其他疾病的背景下，改善淋巴异常的治疗和预防策略 疾病状态，包括肺切除术和其他导致PBF增加的血管异常。

PROJECT SUMMARY / ABSTRACT Aberrations in lymphatic structure and function are increasingly recognized as a significant source of morbidity in a variety of disease states. For example, lymphatic abnormalities associated with congenital heart disease (CHD) that result in increased pulmonary blood flow (PBF) include congenital or acquired chylothoraces, and immunologic aberrations. Importantly, it is increasingly appreciated that lymphatic abnormalities are not only associated with a variety of pulmonary diseases but participate in their pathogenesis. Recent recognition that abnormal respiratory dysfunction often persists years after cardiac correction and is an independent risk factor for mortality in adult CHD patients has brought renewed urgency to better understand the underlying lymphatic pathobiology in CHD, which thus far remains largely unknown. We have previously used a clinically relevant large animal model of CHD with increased PBF (shunt) in combination with isolated vessel reactivity of the thoracic duct and primary lymphatic endothelial cell (LEC) culture, to demonstrate that chronically increased PBF and the consequential increase in lymphatic flow, is associated with: 1) abnormal pulmonary lymphatic flow and architecture; 2) increased mitochondrial reactive oxygen species (mtROS)-driven hypoxia inducible factor-1 (HIF-1) activity and metabolic reprograming to support cellular and proliferation; and 3) a KLF2-dependent decrease in nitric oxide (NO) signaling. In this renewal application we will test our novel hypothesis that in the setting of increased PBF, the mechanosensory channel Piezo1 plays a pivotal role sensing alterations in lymphatic flow, triggering downstream increases in endothelin-1 (ET-1) and mtROS driven HIF-1a activity. This results in decreased NO bioavailability and subsequent lymphatic dysfunction, that contributes to persistently abnormal respiratory mechanics even after the cardiac defect has been repaired. In support of this hypothesis, we present preliminary evidence demonstrating: 1) increased lymphatic endothelial Piezo1, ET-1, RhoA, and mtROS in shunt LECs; 2) Piezo1-, ET-1-, and mtROS-dependent increases in HIF-1 in control LECs; 3) shunt lambs have abnormal respiratory mechanics and lymphatic endothelial dysfunction that persists following closure of the shunt, despite normalized hemodynamics, and 4) that treatment with a mitochondrially-targeted antioxidant (mitoquinone, MitoQ) reverses the HIF-1 mediated shunt LEC phenotype in vitro and normalizes pulmonary lymphatic architecture and function in vivo. This overall hypothesis will be tested in three inter-related, but independent mechanistic aims, that utilize integrated physiologic, cellular, and molecular experiments. These translational and targetable studies include: 1) whole animal hemodynamic physiologic studies, advanced CT/MR imaging, and sophisticated pulmonary function testing, 2) ex vivo thoracic duct reactivity studies, and 3) transcriptional and metabolic studies in LECs. A deeper understanding of the mechanisms investigated may lead to improved treatment and prevention strategies for lymphatic abnormalities in the setting of CHD and other disease states, including pneumonectomy and other vascular abnormalities that result in increased PBF.