Role of neutrophils and eosinophils in bacterial ligand-induced vasculitis

项目摘要 川崎病（KD）是美国儿童获得性心脏病的主要原因， 引起冠状动脉瘤（CAA）的发热性疾病和病因不明的系统性血管炎， 导致长期的心血管后遗症。而静脉注射免疫球蛋白（IVIG）治疗降低CAA 当KD发展至5%时，高达20%的KD患者是IVIG耐药的，并且具有更大的冠状动脉粥样硬化风险。 炎症更好地理解导致KD发展的免疫病理机制 血管炎是最优先的研究项目之一。最近的遗传数据和实验小鼠模型的数据 的KD，都集中在IL-1 β信号转导在KD病变的发病机制中的关键作用。两项临床 最近在对IVIG无反应的KD患者中开始了使用IL-1 R拮抗剂的试验。研究 需要确定参与IL-1β产生的潜在免疫特异性机制， 关于哪些免疫细胞亚群在KD血管炎期间产生IL-1β是已知的。通过使用KD小鼠模型， 血管炎与冠状动脉炎症和腹主动脉瘤的发展，我们发现， 炎症性血管病变被表达高水平IL 1b、Nlrp 3的中性粒细胞和嗜酸性粒细胞浸润， 和Padi 4转录物，后者编码PAD 4，一种已知在细胞外中性粒细胞中起关键作用的蛋白质 陷阱（NET）的形成。我们的初步数据还表明，PAD 4抑制不仅阻断IL-1β， 在体外生产，但也防止LCWE诱导的KD血管炎在体内，这种封锁如何直接影响NET 嗜酸性粒细胞胞外陷阱（Escherichia coli extracellular trap，Escherichia coli）的形成及其IL-1β的产生尚不清楚。我们的新数据 还证明IL-33是致病性的，并且可以促进嗜酸性粒细胞的促炎功能 通过IL-33受体ST 2因此，根据我们的初步数据， 应用是活化的中性粒细胞和嗜酸性粒细胞促进LCWE诱导的KD血管炎， PAD 4依赖性释放NET和雌二醇、生物活性IL-1β和其他促炎介质。在这里， 我们将研究嗜酸性粒细胞和中性粒细胞在小鼠KD血管炎中的作用，并提出干预措施。 目的是阻断这些细胞产生IL-1β和PAD 4信号，以及破坏IL-33信号 对嗜酸性粒细胞，这可能导致炎症减少和KD病变的预防。调查这一 中心假设，我们提出以下具体目标：1）确定浸润中性粒细胞的作用 在LCWE诱导的KD血管炎期间，2）确定组织浸润性嗜酸性粒细胞在LCWE诱导的KD血管炎期间的作用。 LCWE诱导的KD血管炎和3）确定PAD 4在LCWE诱导的KD血管炎期间在中性粒细胞和嗜酸性粒细胞中的作用。 LCWE诱导的KD血管炎。这些研究的成功结论将显著改变KD的方式， 了解并影响新疗法的发展。

PROJECT ABSTRACT Kawasaki disease (KD), the leading cause of acquired heart disease among children in the US, is an acute febrile illness and systemic vasculitis of unknown etiology that causes coronary artery aneurysms (CAA) and can result in long-term cardiovascular sequelae. While Intravenous immunoglobulin (IVIG) treatment lowers CAA development to 5%, up to 20% of KD patients are IVIG-resistant and have a greater risk for coronary inflammation. A better understanding of the immune pathological mechanisms leading to the development of KD vasculitis is one of the highest research priorities. Recent genetic data, and data from experimental mouse model of KD, have all converged on the critical role of IL-1 signaling in pathogenesis of the KD lesions. Two clinical trials using the IL-1R antagonist were recently initiated in KD patients who do not respond to IVIG. Studies identifying the underlying immune-specific mechanisms involved in IL-1β production are needed and little is known regarding which immune cell subsets produce IL-1β during KD vasculitis. By using a murine model of KD vasculitis associated with coronary artery inflammation and abdominal aorta aneurysm development, we found that inflamed vascular lesions are infiltrated by neutrophils and eosinophils that express high levels of Il1b, Nlrp3 and Padi4 transcripts, the latter one encodes PAD4, a protein known for its crucial role in neutrophils extracellular traps (NETs) formation. Our preliminary data also demonstrate that PAD4 inhibition blocks not only IL-1β production in vitro but also prevents LCWE-induced KD vasculitis in vivo, how this blockade directly affect NETs and eosinophils extracellular traps (EETs) formation and their IL-1β production remain unknown. Our new data also demonstrate that IL-33 is pathogenic and may promote the pro-inflammatory functions of eosinophils through the IL-33 receptor, ST2. Therefore, based on our preliminary data, the central hypothesis from this application is that activated neutrophils and eosinophils promote LCWE-induced KD vasculitis through a PAD4-dependent release of NETs and EETs, bioactive IL-1β and other pro-inflammatory mediators. Here, we will investigate the role of eosinophils and neutrophils during murine KD vasculitis and propose interventions aiming to block IL-1β production by those cells and PAD4 signaling, as well as the disruption of IL-33 signaling on eosinophils, which may result in decreased inflammation and the prevention of KD lesions. To investigate this central hypothesis, we propose the following specific aims: 1) Determine the role of infiltrating neutrophils during LCWE-induced KD vasculitis, 2) Determine the role of tissue-infiltrating eosinophils during LCWE-induced KD vasculitis and 3)Determine the role of PAD4 in neutrophils and eosinophils during LCWE-induced KD vasculitis. The successful conclusion of these studies will significantly alter the way KD is understood and influence the development of new therapies.