Mechanisms of neutrophil dysfunction in antifungal immunity

摘要 白色念珠菌是一种寄生于口腔和肠道粘膜的共生真菌。通常， 健康的人有效地控制了白色念珠菌的感染。然而，在某些预处置条件下，例如 免疫抑制、抗生素治疗、腹部手术、侵入性医疗干预或肾脏的使用 在疾病方面，白色念珠菌可导致危及生命的播散性念珠菌病。尽管血液透析是一种 肾脏疾病患者血液感染的主要原因，DC的死亡率是 有肾功能损害的患者比无肾功能障碍的患者多。因此，肾脏疾病是一种独立的 以及这些患者死于DC的主要危险因素，这在很大程度上被忽视了。原因尚不清楚。 与肾功能正常的患者相比，肾脏疾病患者对抗DC的能力较差。使用 在临床相关的小鼠肾脏疾病模型中，我们发现肾功能障碍的小鼠要多得多 对DC易感的动物比对照动物。然而，抗真菌药物缺陷的潜在机制 肾脏疾病的免疫力还没有明确的定义。有趣的是，我们发现了一个意想不到的角色 尿毒症，特征是在没有肾功能的情况下尿毒症毒素(S)在血液中蓄积 导致DC中性粒细胞功能障碍。我们的数据暗示尿毒症会导致活性氧的缺陷。 由中性粒细胞产生的(ROS)，这对消除真菌是必不可少的。在某种程度上，我们表明这是由于 葡萄糖转运蛋白1介导的中性粒细胞摄取葡萄糖的缺陷，这是糖酵解途径所必需的 ROS一代的上游。我们的假设是中性粒细胞内源性损伤在念珠菌杀伤功能中的作用 中性粒细胞使尿毒症患者更容易死于DC。在目标1中，我们将使用一系列的体外 以及体内方法来确定葡萄糖摄取缺陷的潜在细胞和分子机制 以及随后尿毒症期间中性粒细胞的ROS产生和抗真菌活性的损害。知识 从这些研究中获得的结果将被用于鉴定具有中性粒细胞抑制活性的潜在尿毒症毒素(S)。 我们还将设计新的治疗方法来纠正细胞代谢途径的异常和 肾脏疾病中的中性粒细胞功能障碍。在目标2中，我们将翻译和验证我们的小鼠模型结果 肾脏病患者血液透析前后生物标本采集及比较 中性粒细胞对健康人的抗真菌活性。这项提案的目标是定义 肾脏疾病中性粒细胞抗真菌活性的缺陷，并最终利用这一信息 治疗效果。我们的长期目标是减少与这一毁灭性事件相关的死亡率 肾脏疾病患者医院感染情况分析。

ABSTRACT Candida albicans is a commensal fungus that resides in the oral cavity and gut mucosa. Normally, healthy individuals efficiently control C. albicans infection. However, in certain pre-disposing conditions such as immunosuppression, antibiotic therapy, abdominal surgery, use of invasive medical interventions or kidney diseases, C. albicans can cause life-threatening disseminated candidiasis (DC). Although hemodialysis is a major cause of bloodstream infection in patients with kidney disease, mortality due to DC is 2 times higher in patients with kidney impairment than individuals without renal dysfunction. Thus, kidney disease is a separate and major risk factor for death from DC in these patients, which has largely been overlooked. It is unknown why patients with renal ailment are inept to fight DC compared to individuals with normal kidney function. Using a clinically relevant mouse model of renal disease, we show that mice with kidney dysfunction are far more susceptible to DC than control animals. Nevertheless, the underlying mechanisms of defect in antifungal immunity in kidney disease are poorly defined. Interestingly, we have discovered an unanticipated role for uremia, characterized by the accumulation of uremic toxin(s) in the blood in the absence of kidney function, in causing neutrophil dysfunction in DC. Our data imply that uremia induces a defect in reactive oxygen species (ROS) generation by neutrophils, which is essential for the elimination of fungi. In part, we show that this is due to a defect in glucose transporter1-mediated uptake of glucose by neutrophils, required for glycolytic pathways upstream of ROS generation. Our hypothesis is that neutrophil-intrinsic impairment in candidacidal function of neutrophils makes uremic patients more susceptible to death from DC. In Aim 1, we will employ series of in vitro and in vivo approaches to define the underlying cellular and molecular mechanisms of defect in glucose uptake and subsequent impairment in ROS production and antifungal activity of neutrophils during uremia. Knowledge gained from these studies will be utilized to identify potential uremic toxin(s) with neutrophil inhibitory activity. We will also device novel therapeutic approaches to correct the abnormalities in cell metabolic pathways and neutrophil dysfunction in kidney diseases. In Aim 2, we will translate and validate our mouse model findings in patients with kidney disease by collecting biospecimens from pre- and post-hemodialysis patients and compare antifungal activity of neutrophils to healthy subjects. The goal of this proposal is to define the mechanisms of defect in antifungal activity of neutrophils in kidney disease and eventually to exploit this information for therapeutic benefit. Our long-term objective is to reduce the mortality associated with this devastating nosocomial infection in patients with kidney disease.