Role of ADAM17 in MDSC-Mediated Development of Pulmonary Hypertension

项目总结 虽然已知通过抑制趋化因子受体CXCR2来减少白细胞募集 减轻小鼠疾病模型的肺动脉高压(PH)的发展，并激活PEP-1。 潮酶ADAM17水平与改善血管重塑有关-ADAM17在CXCR2中的作用- 介导的髓系细胞转运导致PH的发生尚不清楚。有迫切的需要关闭 这一认识上的差距是因为，在完成之前，髓系来源的抑制的免疫治疗调节- SOR细胞(MDSC)在肺血管疾病发展中的作用仍遥不可及。这个 拟议实验的总体目标是确定ADAM17在中性粒细胞中的作用。 MDSC(PMN-MDSC)在肺血管内募集。中心假设是减少的ADAM17 PMN-MDSC的表达和活性是这些细胞向肺血管系统募集所必需的 导致PH。这一假设的科学前提是在初步数据的基础上提出的 证明表达CXCR2的PMN-MDSC在高血压动物模型中是必需的 这种循环细胞群在IPF患者的全血中出现的程度更高。 此外，ADAM17水平与CXCR2的表达呈负相关，并与发育相关 严重的PH值。拟议研究的理由是，在研究完成后，将有可能 将当前针对MDSC的治疗方法应用于疾病预防和治疗，并告知潜在的危害 在使用ADAM17靶向治疗其他疾病方面。核心假说将通过追查来检验 具体目的如下：1)检验ADAM17的表达和功能活性存在差异的假设 从PH和特发性肺纤维化(IPF)患者分离的PMN-MDSC中进行调节，以及2)检测 假设PMN-MDSC表达ADAM17对病理性肺血管重建有保护作用 英。在第一个目标中，将采集患有和不伴有PH的IPF患者的外周血液样本。 为了确定疾病患者和对照组的MDSC图谱，基于流式细胞术分析 MDSC子类型。然后将对细胞群体进行特征描述，以识别已识别的生物标志物的等位基因识别 候选，除了评估ADAM17的功能活性，包括脱落和蛋白分解活性。 在第二个目的中，野生型和转基因小鼠在髓系细胞(LysM.Cre-1)中缺失ADAM17。 ADAM17fl/fl小鼠)将被用来确定组织特异性基因表达对发育的影响。 两种疾病模型(博莱霉素性肺纤维化和慢性缺氧)的PH值变化。在COM之后- 这项研究的贡献将是巨大的，因为它代表了一种可翻译的改进策略 通过防止骨髓间充质干细胞转运到肺部的临床结果。建议的研究是创新的，因为- 因为它代表了对现状的实质性偏离，将重点从血管扩张剂治疗转向 微调免疫调节介质MDSC在继发于IPF的PH病理生物学中的作用

PROJECT SUMMARY While it is known that a reduction in leukocyte recruitment through inhibition of chemokine receptor CXCR2 attenuates development of pulmonary hypertension (PH) in murine models of disease – and that activated pep- tidase ADAM17 levels are associated with improved vascular remodeling – the role of ADAM17 in CXCR2- mediated myeloid cell trafficking leading to the development of PH is unknown. There is an urgent need to close this gap in knowledge because, until accomplished, immunotherapeutic modulation of myeloid-derived suppres- sor cell (MDSC) contribution to the development of pulmonary vascular disease will remain beyond reach. The overall objective of the proposed experiments is to define the contribution of ADAM17 in polymorphonuclear- MDSC (PMN-MDSC) recruitment within the lung vasculature. The central hypothesis is that reduced ADAM17 expression and activity by PMN-MDSC is necessary for recruitment of these cells to the pulmonary vasculature leading to PH. The scientific premise for this hypothesis has been formulated on the basis of preliminary data demonstrating that PMN-MDSC expressing CXCR2 are necessary for development of PH in animal models of disease, and that this circulating cell population is present to a higher degree in whole blood of IPF patients. Additionally, ADAM17 levels inversely correlate with CXCR2 expression, and are associated with development of severe PH. The rationale for the proposed research is that, upon completion of the studies it will be possible to apply current MDSC-targeted therapies to disease prevention and treatment, as well as inform potential harms in the use of ADAM17-targeted treatments for other diseases. The central hypothesis will be tested by pursuing the following specific aims: 1) test the hypothesis that ADAM17 expression and functional activity is differentially regulated in PMN-MDSC isolated from patients with PH and idiopathic pulmonary fibrosis (IPF), and 2) test the hypothesis that ADAM17 expression by PMN-MDSC protects against pathologic pulmonary vascular remodel- ing. In the first aim, peripheral blood samples from patients with IPF with and without PH will be collected, in order to define a MDSC profile in patients with disease and controls, based upon flow cytometric analysis for MDSC sub-types. Cell populations will then be characterized for allelic discrimination of an identified biomarker candidate, in addition to assessment of ADAM17 functional activity, including shedding and proteolytic activity. In the second aim, wild type and transgenic mice with deletion of ADAM17 in myeloid-derived cells (LysM.Cre- ADAM17fl/fl mice) will be used to determine the effect tissue-specific gene expression will have on the develop- ment of PH in two models of disease (bleomycin-induced pulmonary fibrosis and chronic hypoxia). Upon com- pletion, the contribution of this study will be significant because it represents a translatable strategy to improve clinical outcomes through prevention of MDSC trafficking to the lung. The proposed research is innovative be- cause it represents a substantive departure from the status quo by shifting focus from vasodilator therapy to a fine-tuned immunoregulatory mediator, MDSC, in the pathobiology of PH secondary to IPF.