Subcellular Mechanisms for Fungal Phagosome Maturation in Macrophages

描述（由申请人提供）：侵袭性真菌感染与通常超过90%的高死亡率相关，对免疫功能低下的患者产生不利影响，在美国患者群体迅速增长。旨在治疗破坏性疾病如自身免疫炎性综合征（例如类风湿性关节炎、克罗恩病、溃疡性结肠炎）的免疫调节治疗剂的出现和使用为患者提供了对其疾病的良好控制。实体和骨髓移植患者也受益于更有效的免疫抑制剂，使更复杂的供体-受体器官匹配成为真实的可能性。不幸的是，这些生物和化学治疗剂不是特异性的，并且广泛地抑制免疫力，通常使患者容易受到严重的侵袭性真菌感染，包括念珠菌属，曲霉属和二型生物体，并且代表了我们的医疗保健系统中日益增长的未满足的需求。真菌清除的过程开始于先天免疫细胞识别富含碳水化合物的真菌细胞壁，随后是吞噬作用和吞噬溶酶体的形成。吞噬体成熟是一个动态的过程，是刺激持久的适应性免疫的核心，但仍然知之甚少。在这项申请中，候选人提出了K 08指导临床科学家研究职业发展奖，该奖项将解决真菌碳水化合物吞噬体成熟所需的一些关键亚细胞分子机制及其对T细胞活化的影响。为了确定巨噬细胞中的亚细胞机制，形成了由碳水化合物缀合珠（FLP）组成的新型真菌样颗粒系统。使用ε-1，3-葡聚糖FLP分析纯化的巨噬细胞吞噬体。数据表明凝集素受体Dectin-1对<$-1，3-葡聚糖FLP的表面识别控制酸化和吞噬溶酶体的形成。候选人假设Dectin-1特异性信号传导将决定所招募的吞噬体蛋白库的组成。具体而言，该提案的目标将：1）定义Dectin-1信号传导在将Rab 7 b募集到真菌吞噬体中的作用，2）描绘NLRP 3炎性体对吞噬体成熟的贡献，3）确定Dectin-1信号传导对II类MHC抗原呈递和CD 4 + T细胞刺激的作用。该候选人已完成了在联合马萨诸塞州总医院和布里格姆和妇女传染病计划的临床奖学金。他在真菌免疫方面有研究经验，曾研究过抗隐球菌免疫，作为他博士学位的一部分。论文工作，这与他提出的培训计划相吻合。这项职业发展资助概述了教学和实践的实验室研究培训，重点是对真菌碳水化合物的免疫反应，提高了我们对开发新型真菌疫苗策略所必需的宿主-真菌相互作用的理解，并为候选人提供了必要的工具，以发展成为独立的生物医学研究者。

DESCRIPTION (provided by applicant): Invasive fungal infections are associated with high mortality rates often exceeding 90%, adversely affecting immunocompromised patients, a rapidly growing patient population in the United States. The advent and use of immune modulating therapeutics aimed at treating devastating diseases such as autoimmune inflammatory syndromes (e.g. rheumatoid arthritis, Crohn's, ulcerative colitis) has provided patients with excellent control of their disease. Solid and bone marrow transplant patients have also benefited from a more potent arsenal of immune suppressive agents making more complicated donor-recipient organ matches a real possibility. Unfortunately, these biologic and chemotherapeutic agents are not specific and act to suppress immunity broadly, often leaving patients susceptible to severe invasive fungal infections including Candida, Aspergillus and dimorphic organisms, and represents a growing unmet need in our healthcare system. The process of fungal elimination begins with innate immune cell recognition of the carbohydrate-rich fungal cell wall followed by phagocytosis and the formation of phagolysosomes. Phagosomal maturation is a dynamic process that is central to the stimulation of lasting adaptive immunity, yet remains poorly understood. In this application, the candidate proposes a K08 Mentored Clinical Scientist Research Career Development Award grant that will address some of the critical subcellular molecular mechanisms required for fungal carbohydrate phagosomal maturation and their influence on T cell activation. To define the subcellular mechanisms in macrophages, a novel fungal-like particle system composed of carbohydrate-conjugated beads (FLP) was formed. ¿-1,3-glucan FLP were used to analyze purified macrophage phagosomes. Data suggests that surface recognition of ¿ -1,3- glucan FLP by the lectin receptor, Dectin-1, controls acidification and phagolysosomal formation. The candidate hypothesizes that Dectin-1-specific signaling will dictate the composition of the recruited phagosomal protein repertoire. Specifically, the proposal aims will: 1) define the role Dectin-1 signaling in recruiting Rab7b to the fungal phagosome, 2) delineate the contribution of the NLRP3 inflammasome to phagosomal maturation, 3) determine the role of Dectin-1 signaling to class II MHC antigen presentation and CD4+ T cell stimulation. The candidate has completed a clinical fellowship in the combined Massachusetts General Hospital and Brigham and Women's Infectious Diseases Program. He has research experience in fungal immunity having studied anti-cryptococcal immunity, as part of his Ph.D. thesis work, which dovetails with his proposed training program. This career development grant outlines both didactic and practical bench- side research training focused on immune responses to fungal carbohydrates, improves our understanding of host-fungal interactions essential for the development of novel fungal vaccine strategies and provides the candidate with the necessary tools to develop into an independent biomedical investigator.