Aveolar Macrophage Apoptosis and Pneumocystis

卡氏肺孢子虫(在人类疾病中称为吉罗维氏肺孢子虫)在免疫接种后引起严重肺炎。 个人，如艾滋病患者。人类肺泡巨噬细胞数量减少 肺孢子虫肺炎(PEP)。在大鼠和小鼠PEP模型中，肺泡巨噬细胞数量减少 大约60%，主要是由于肺泡巨噬细胞凋亡率的增加。在PEP期间， 多胺(亚精胺、乙酰精胺和乙酰亚精胺)在肺泡和肺组织中的水平显著增加。 肺泡巨噬细胞。来自PEP动物的支气管肺泡灌洗液(BAL)能够诱导 正常肺泡巨噬细胞的凋亡和肺泡灌洗液中多胺的耗竭 它们诱导细胞凋亡的能力。这项提议将使用类固醇免疫抑制的大鼠和L3T4细胞- 耗尽小鼠来验证多胺直接导致肺泡巨噬细胞凋亡的假说 或间接地由PEP过程中多胺分解代谢产生的活性氧物种所引起。 将进行实验以确定多胺是否存在于肺泡和肺泡中 PEP中的巨噬细胞来源于肺孢子虫、肺泡巨噬细胞和/或肺 上皮细胞。诱导肺泡巨噬细胞凋亡所需的每种特定多胺的水平 将会被确定。还将评估肺泡巨噬细胞摄取多胺的变化。这个 我们将研究活性氧水平升高与多胺之间的关系。支持- 并将确定参与细胞凋亡的抗凋亡因子，以及多胺对细胞凋亡的影响。 这些因子的表达和活性将被研究。外在的和内在的参与 将通过识别改变线粒体膜的因素来研究(线粒体)凋亡途径 可能导致细胞色素c释放到细胞质以及死亡受体和 它们的配体与细胞凋亡有关。抗细胞凋亡因子下调对人肺癌耐药的影响 肺泡巨噬细胞对多胺的介导，肺孢子虫诱导的细胞凋亡也将被研究。 由于对大鼠和小鼠PEP的初步研究表明，肺泡细胞凋亡受到抑制 巨噬细胞可以减缓疾病的进展，甚至可以解决感染，拟议的研究可能 导致治疗肺孢子虫肺炎的新方法。

Pneumocystis carinii (P. jiroveci in human disease) causes a severe pneumonia in irnmunocornprornised individuals, such as those with AIDS. The number of alveolar macrophages is decreased in humans with Pneumocystis pneumonia (Pep). In rat and mouse Pep models, alveolar macrophage number is decreased by approximately 60% mainly due to the increased rate of apoptosis in alveolar macrophages. During Pep, polyamine (spermidine, acetylspermine, and acetylspermidine) levels are greatly increased in the alveoli and alveolar macrophages. Bronchoalveolar lavage (BAL) fluids from animals with Pep are able to induce apoptosis in normal alveolar macrophages, and depletion of polyamines from these BAL fluids abrogates their ability to induce apoptosis. This proposal will use steroid-immunosuppressed rats and L3T4 cell- depleted mice to test the hypothesis that alveolar macrophages apoptosis is caused directly by polyamines or indirectly by reactive oxygen species that are generated as the result of polyamine catabolism during Pep. Experiments will be performed to determine whether the polyamines present in the alveoli and alveolar macrophage during Pep are derived from Pneumocystis organisms, alveolar macrophages, and/or lung epithelial cells. The levels of each specific polyamine needed to induce apoptosis in alveolar macrophages will be determined. Changes in polyamine uptake by alveolar macrophages will also be assessed. The relationship between increased levels of reactive oxygen species and polyamines will be investigated. Pro- and anti-apoptosisfactors that are involved in the apoptosis will be identified, and effects of polyamines on the expression and the activity of these factors will be investigated. The involvement of extrinsic and intrinsic (mitochondrial) apoptosis pathways will be studied by identifying factors that alter mitochondrial membrane potential leading to release of cytochrome c to the cytoplasm and the contribution of death receptors and their ligands to the apoptosis. Effects of down regulation of anti-apoptotic factors on the resistance of alveolar macrophage to polyamine-mediated, Pneumocystis-induced apoptosis will also be investigated. Since preliminary studies in both rats and mice with Pep indicate that inhibition of apoptosis in alveolar macrophages ameliorates disease progression or even resolves the infection, the proposed studies may lead to new treatments for Pneumocystis pneumonia.