Role of Resident Monocytes in the Pathogenesis of Pulmonary Arterial Hypertension

 描述(由申请人提供)：职业发展目标/计划：申请人的长期目标是促进科学知识，提高肺动脉高压患者的生活质量。申请者的总体目标是成为一名专门从事肺血管免疫生物学的独立内科科学家。为了实现这一目标，申请者设计了一项职业发展计划，其中包括以下内容：包括正规课程和其他教学内容的课程，以增强基础科学背景、写作技能和批判性分析；至少75%的研究时间通过实践实验室经验来发展新的技术技能；以及由有经验的内科科学家进行密切指导，以确保成功过渡到独立。拟议的研究项目结合了申请者在免疫学方面的背景和对肺血管生物学的兴趣，并将作为一个平台来发展一条独立的研究路线。研究：肺动脉高压(PAH)是一组肺小动脉异常重构和狭窄，导致肺动脉压升高、右心衰竭、严重缺氧并最终死亡的疾病。即使使用已知的治疗方法，死亡率仍然很高。需要更好地了解PAH的发病机制，以确定潜在的治疗靶点。大量证据表明，单核细胞、巨噬细胞和树突状细胞等髓系细胞对肺血管的侵袭在PAH的发生发展中起重要作用。然而，无论是渗透到肺动脉的特定髓系细胞群，还是这些细胞的活性，都没有被确定。使用PAH的慢性缺氧模型，我的初步数据显示，驻留的单核细胞聚集在肺小动脉周围，促进PAH。我的假设是，常驻单核细胞渗入肺血管，并在低氧刺激下启动炎症反应，分化为具有血管重塑活性的细胞，从而促进PAH的发展。为了验证这一假设，我们将利用一种新的转基因小鼠品系，该品系在常驻单核细胞中特异地表达Cre重组酶。利用这些小鼠，我们建立了1)驻留单核细胞特异性荧光报告程序，2)可诱导的驻留单核细胞消融，和3)驻留单核细胞特异性基因敲除的模型。在目标1中，我们将特异性地删除常驻单核细胞中的中枢缺氧感觉分子-缺氧诱导因子(HIF)，以确定常驻单核细胞在感知缺氧和PAH发病机制中的作用。在目标2中，利用我们在体内消耗驻留单核细胞的能力，我们将确定驻留单核细胞在这种疾病的发生和发展中的作用。我们期望来自拟议的实验的发现将提高我们对单核细胞生物学、HIF调节以及驻留单核细胞在PAH发病机制中的作用的认识。

 DESCRIPTION (provided by applicant): Career Development Goal/Plan: The long-term goal of the applicant is to contribute to scientific knowledge and improve quality of life for patients with pulmonary arterial hypertension. The overall objective of the applicant is to become an independent physician scientist specializing in pulmonary vascular immunobiology. To achieve this objective, the applicant has designed a career development plan that incorporates the following: a curriculum involving formal classes and other didactic teachings that enhance basic science background, writing skills, and critical analysis; at least 75% protected research time with hands-on laboratory experiences to develop new technical skills; and close mentoring by accomplished physician-scientists to ensure a successful transition into independence. The proposed research project combines the applicant's background in immunology and interest in pulmonary vascular biology and will serve as a platform to develop an independent line of research. Research: Pulmonary arterial hypertension (PAH) is a group of diseases caused by abnormal remodeling and narrowing of small pulmonary arterioles, leading to elevation of pulmonary arterial pressure, right heart failure, severe hypoxia, and eventual death. Even with known treatments, mortality remains high. Better understanding of PAH pathogenesis is needed to identify potential therapeutic targets. Substantial evidence suggests that the infiltration of pulmonary vessels by myeloid cells, such as monocytes, macrophages and dendritic cells, have a critical role in the development of PAH. However, neither the specific myeloid cell population that infiltrates pulmonary arteries, nor the activity of these cells has been deter- mined. Using chronic hypoxia models of PAH, my preliminary data demonstrates that resident monocytes accumulate around the pulmonary arterioles and promote PAH. My hypothesis is that resident monocytes infiltrate pulmonary vessels and, in response to hypoxic stimuli, initiate inflammatory responses and differentiate into cells with vascular remodeling activity, thereby promoting PAH development. To test this hypothesis, we will take advantage of a novel line of transgenic mice that expresses Cre recombinase specifically in resident monocytes. Using these mice, we have developed models of 1) resident monocyte- specific fluorescent reporters, 2) inducible resident monocyte ablation, and 3) resident monocyte-specific gene knockouts. In Aim 1, we will specifically delete hypoxia-inducible factors (HIFs), the central hypoxia- sensory molecules, in resident monocytes to determine the role of resident monocytes in sensing hypoxia and PAH pathogenesis. In Aim 2, utilizing our capacity to deplete resident monocytes in vivo, we will determine the contribution of resident monocytes to both the development and progression of this disease. We expect findings from the proposed experiments will improve our insight into monocyte biology, HIF regulation, and role of resident monocytes in PAH pathogenesis.