miR-29b and autophagy regulate alveolar macrophage function post-BMT

miR-29b 和自噬调节 BMT 后肺泡巨噬细胞功能

• 批准号: 9189677
• 负责人: Bethany B. Moore
• 金额: $ 42.64万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-01-15 至 2019-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9189677
• 关键词: Abbreviations; Acute; Allogenic; Alveolar Macrophages; Arachidonate 5-Lipoxygenase; Arachidonic Acids; Autologous; Autophagocytosis; Bacteria; Bacterial Infections; Bone Marrow Transplantation; Cells; Complement Factor B; Cyclooxygenase Inhibitors; DNA Modification Methylases; DNA biosynthesis; Data; Defect; Dinoprostone; Disease; Epithelial Cells; Genes; Genetic; Hematopoietic; Hematopoietic Stem Cell Transplantation; Hematopoietic System; Host Defense; Human; Immune; Impairment; In Vitro; Incidence; Infection; Leukotrienes; Lung; Malignant - descriptor; Malignant Neoplasms; Mediating; Metabolism; Mus; Mutation; Natural Immunity; Pathway interactions; Patients; Phagocytes; Phagocytosis; Pharmacology; Predisposition; Production; Prostaglandin Inhibition; Prostaglandin-Endoperoxide Synthase; Prostaglandins; Pseudomonas aeruginosa; Regimen; Role; Safety; Shunt Device; Signal Transduction; Streptococcus pneumoniae; Structure; Testing; Therapeutic; Transforming Growth Factor beta; Transforming Growth Factors; Transplantation; Treatment Efficacy; Up-Regulation; Work; conditioning; cyclooxygenase 2; cytokine; fighting; improved; in vivo; innate immune function; insight; killings; macrophage; man; mouse model; neutrophil; novel therapeutics; overexpression; pathogen; public health relevance; receptor; reconstitution; scavenger receptor; targeted treatment

 DESCRIPTION (provided by applicant): Hematopoietic stem cell transplantation (HSCT) is used to treat a variety of genetic defects and malignancies, but its usefulness is limited by pulmonary infections. Infectious complications can occur both in allogeneic and autologous transplant settings and susceptibility to infection remains elevated despite hematopoietic reconstitution. To better understand innate immune deficiencies that characterize HSCT, we developed a murine model of bacterial infection post-syngeneic (syn) bone marrow transplant (BMT). We have previously shown that these mice are more susceptible to infection with Pseudomonas aeruginosa even after the hematopoietic system is reconstituted. We identified the upregulation of cyclooxygenase-2 (COX-2) and the overproduction of PGE2 as major contributing factors to the impaired innate immune function in these mice. We identified that alveolar macrophages (AMs) and neutrophils (PMNs) had defects in innate immune functions such as phagocytosis, bacterial killing and cytokine secretion. In addition, the profile of scavenger receptors on AMs were altered post-BMT, with loss of macrophage receptor with collagenous structure (MARCO), a critical receptor for recognition of P. aeurignosa. We determined that PGE2 signaled via elevated E prostanoid 2 (EP2) receptors on these AMs to inhibit their functions. Importantly, our murine studies have shown that pharmacologic or genetic inhibition of COX-2 post-BMT restores lung innate immunity and AM function against P. aeruginosa. These results are exciting because they suggest inhibition of PGE2 signaling can be a therapeutic to improve host defense post-transplant. However, there are systemic problems with a therapeutic strategy that globally blocks all prostaglandin synthesis. Thus, one aspect of this proposal will be to test a newly developed EP2 antagonist (PF-044148948) which we have obtained from Pfizer. We believe this will be a much more specific and effective therapeutic to block the inhibitory PGE2 signaling. The application also seeks to provide insight into the following unanswered questions. 1) Why is COX-2 elevated post-BMT leading to overproduction of PGE2? 2) Do these same innate immune defects characterize allogeneic (allo) BMT? 3) Do these defects post-BMT make mice more susceptible to Gram positive infections (like Streptococcus pneumoniae) as well as Gram negative ones? 4) Can we determine whether impairment of autophagy is one mechanism for impaired killing post-BMT? 5) Are the defects we have noted in our murine model also present in human HSCT patients? Our overall hypothesis is: BMT conditioning induces transforming growth factor (TGF) ß secretion from lung epithelial cells. This augments miR-29b expression to block synthesis of DNA methyltransferases (DNMTs) causing hypomethylation of COX-2 leading to PGE2 overexpression in AMs. Furthermore, PGE2-EP2 induced alterations in autophagy impair host defense against P. aeruginosa and S. pneumoniae post-BMT and we speculate that host defense post-BMT can be improved via treatment with a COX inhibitor, an EP2 antagonist or via induction of autophagy. These hypotheses will be explored in the following specific aims. Aim 1) To determine if syn BMT and allo BMT mice are more susceptible to P. aeruginosa and S. pneumoniae infection and if susceptibility is related to PGE2 signaling via EP2 in mice and man Aim 2: To determine whether TGFß-induced miR-29b causes COX-2 hypomethylation to increase PGE2 production post-BMT Aim 3: Aim 3: To determine if autophagy is impaired in syn and allo BMT AMs, to determine whether this is related to PGE2- EP2 signaling and the importance of autophagy to host defense post-BMT

 描述（由申请人提供）：造血干细胞移植（HSCT）用于治疗多种遗传缺陷和恶性肿瘤，但其用途受到肺部感染的限制。在同种异体和自体移植环境中都可能发生感染并发症，尽管造血重建，但感染的易感性仍然升高。为了更好地了解 HSCT 的先天免疫缺陷特征，我们开发了同基因 (syn) 骨髓移植 (BMT) 后细菌感染的小鼠模型。我们之前已经证明，即使在造血系统重建后，这些小鼠也更容易受到铜绿假单胞菌感染。我们发现环氧合酶-2 (COX-2) 的上调和 PGE2 的过量产生是这些小鼠先天免疫功能受损的主要因素。我们发现肺泡巨噬细胞（AM）和中性粒细胞（PMN）在吞噬、杀灭细菌和分泌细胞因子等先天免疫功能方面存在缺陷。此外，BMT 后 AM 上的清道夫受体谱发生了改变，具有胶原结构的巨噬细胞受体 (MARCO) 丧失，而巨噬细胞受体是识别铜绿假单胞菌的关键受体。我们确定 PGE2 通过这些 AM 上升高的 E 前列腺素 2 (EP2) 受体发出信号来抑制其功能。重要的是，我们的小鼠研究表明，BMT 后对 COX-2 进行药理学或遗传抑制可恢复肺部针对铜绿假单胞菌的先天免疫和 AM 功能。这些结果令人兴奋，因为它们表明抑制 PGE2 信号传导可以成为改善移植后宿主防御的治疗方法。然而，全面阻断所有前列腺素合成的治疗策略存在系统性问题。因此，该提案的一个方面将是测试我们从辉瑞公司获得的新开发的 EP2 拮抗剂 (PF-044148948)。我们相信这将是一种更特异、更有效的阻断抑制性 PGE2 信号传导的治疗方法。该应用程序还旨在深入了解以下未解答的问题。 1) 为什么 BMT 后 COX-2 升高会导致 PGE2 过量产生？ 2) 这些相同的先天免疫缺陷是否是同种异体 (allo) BMT 的特征？ 3）BMT后的这些缺陷是否会使小鼠更容易受到革兰氏阳性菌（如肺炎链球菌）和革兰氏阴性菌感染？ 4) 我们能否确定自噬受损是否是 BMT 后杀伤受损的一种机制？ 5) 我们在小鼠模型中注意到的缺陷是否也存在于人类 HSCT 患者中？我们的总体假设是：BMT 调理诱导肺上皮细胞分泌转化生长因子 (TGF) ß。这增强了 miR-29b 表达，阻止 DNA 甲基转移酶 (DNMT) 的合成，从而导致 COX-2 低甲基化，导致 AM 中 PGE2 过度表达。此外，PGE2-EP2诱导的自噬改变会损害BMT后宿主对铜绿假单胞菌和肺炎链球菌的防御，我们推测BMT后宿主的防御可以通过COX抑制剂、EP2拮抗剂治疗或通过诱导自噬来改善。这些假设将在以下具体目标中进行探讨。目标 1) 确定 syn BMT 和 allo BMT 小鼠是否更容易受到铜绿假单胞菌和肺炎链球菌感染，以及易感性是否与小鼠和人中通过 EP2 的 PGE2 信号转导有关。 目标 2: 确定 TGFβ 诱导的 miR-29b 是否会导致 COX-2 低甲基化，从而增加 BMT 后 PGE2 的产生。 目标 3: 目标 3: 确定 syn 和 S. 肺炎链球菌感染中的自噬是否受损 allo BMT AM，以确定这是否与 PGE2-EP2 信号传导以及自噬对 BMT 后宿主防御的重要性有关