A critical role for macrophage ferroptosis in promoting fungal invasion in lung transplant recipients

项目摘要/摘要 这一应用着重于移植出血引起的铁超载在调节失调中的作用。 对肺巨噬细胞(mɸ，S)和侵袭性曲霉病的促进作用。烟曲霉(Aspergillusfumigatus，Af)是一种 一种无处不在的霉菌，会释放空气中的孢子(分生孢子)，影响全球近2000万人。一合一- 三名肺移植受者患有与曲霉菌相关的肺部疾病。而肺 移植可以挽救数以千计的人的生命，移植后的存活往往受到 房颤感染。为了更好地了解移植(宿主)-Af(病原体)的关系，我们开发了一种小鼠 Af感染的原位气管移植模型。我们已经证明了移植排斥反应介导的 微出血可增加组织铁水平并决定侵袭性。然而，确切的相互作用 在免疫、铁超载和感染之间，人们仍然知之甚少。MɸS是对抗的第一道防线 房颤，也是恢复组织铁稳态的中心。重要的是，我们的初步结果表明 微出血介导的铁超载：(I)深刻影响MFS通过Af分生孢子的杀灭能力 溶酶体酸化缺陷；(Ii)先天免疫反应偏向促炎因子ɸS 导致高水平的组织损伤活性氧物种(ROS)的状态；以及(Iii)铁促进m-ɸ 铁性下垂。铁下垂是一种新发现的调节性细胞死亡形式，由铁的产生引起。 有毒的脂类ROS。铁下垂最初被认为是癌症，但现在已知会导致阿尔茨海默氏症和 帕金森病、缺血再灌注损伤、动脉粥样硬化、急性肾损伤和急性肾损伤的反应 大出血。然而，铁下垂在降低宿主对病原体的防御(如果有的话)方面的作用仍然存在 未知。拟议的研究旨在从Af侵袭的角度解决这些问题。中环 假说是移植物微出血介导的铁超载导致MF铁下垂和极化 转化为一种不受约束的促炎表型，促进房颤的侵袭。特异性靶标1在体外利用和 铁性下垂是由m-ɸS偏振态决定的体内实验 S致移植ɸ无力缓解Af感染及降铁剂的作用研究 以及抗铁下垂药物，以减少真菌的侵袭。特定目标2使用最先进的组学技术来定义 铁诱导的Af蛋白水解酶，并测试了真菌蛋白水解酶抑制可以减轻铁性下垂和 改善气管移植模型的结果。特指3研究S分离的肺泡膜ɸ的能力 人LTRS与非肺移植对Af分生孢子的杀伤作用及其与mɸS杀伤能力的相关性 分生孢子带有mɸS偏振态和铁下垂，用质谱仪测定。这一目标将提供一个直接的 铁超载导致铁性下垂和促炎表型假说的可译性 促进真菌侵袭。这些研究的成功完成将有助于发现一个基本的 新的生物学，并为真菌感染的治疗提供新的靶点。

PROJECT SUMMARY/ ABSTRACT This application focuses on the contribution of transplant hemorrhage-induced iron overload in the dysregulation of pulmonary macrophages (mɸs) and the promotion of invasive aspergillosis. Aspergillus fumigatus (Af) is a ubiquitous mold that releases airborne spores (conidia) and affects nearly 20 million people worldwide. One-in- three lung transplant recipients (LTRs) suffers from Aspergillus-related pulmonary disease. While lung transplantation can be a life-saving treatment for thousands of people, survival post-transplant is often limited by Af infection. To better understand the transplant (host)-Af (pathogen) relationship, we developed a murine orthotopic tracheal transplant (OTT) model of Af infection. We have shown that transplant rejection-mediated microhemorrhage increases tissue iron levels and determines Af invasion. However, the exact interaction between immunity, iron overload and infection are still poorly understood. Mɸs are the first line of defense against Af and are also central to restoring tissue iron homeostasis. Importantly, our preliminary results indicate that microhemorrhage-mediated iron overload: (i) profoundly impacts the ability of mfs to kill Af conidia through a defect in lysosomal acidification; (ii) the innate immune response is polarized toward a pro-inflammatory mɸs state that results in high levels of tissue damaging reactive oxygen species (ROS); and (iii) iron promotes mɸ ferroptosis. Ferroptosis is a newly recognized form of regulated cell death that results from the production of iron toxic lipid ROS. Ferroptosis was first recognized in cancer but is now known to contribute to Alzheimer’s and Parkinson’s disease, ischemia reperfusion injury, atherosclerosis, acute kidney injury and the response to acute hemorrhage. However, the role of ferroptosis in lowering the host’s defense against pathogens, if any, remains unknown. The proposed studies are designed to address these questions in terms of Af invasion. The central hypothesis is that transplant microhemorrhage-mediated iron overload induces mf ferroptosis and polarization into an unrestrained pro-inflammatory phenotype that promotes Af invasion. Specific aim 1 utilizes in vitro and in vivo experiments to investigate the concept that ferroptosis is dictated by mɸs polarization state and contributes to the inability of transplant mɸs to mitigate Af infection and studies the role of iron lowering agents and anti-ferroptotic drugs to decrease fungal invasion. Specific aim 2 uses state-of-art omics techniques to define iron induced Af proteases and tests the concept that fungal protease inhibition can mitigate ferroptosis and improve outcomes in the tracheal transplant model. Specific aim 3 studies the ability of alveolar mɸs isolated from human LTRs compared to non-lung transplants to kill Af conidia and correlates the ability of mɸs to kill conidia with mɸs-polarization state and ferroptosis, using mass cytometry. This aim will provide a direct translatability of the hypothesis that iron overload induces ferroptosis and a pro-inflammatory phenotype that promotes fungal invasion. Successful completion of these studies will allow for the discovery of a fundamental new biology and provide novel targets for the treatment of fungal infections.