Nano and Microscale Molecular Machines for Innate Immune Sensing of Candida

 描述（由申请人提供）：在念珠菌的先天免疫识别过程中，细胞壁配体和模式识别受体的组织是成功免疫激活的重要决定因素。我们研究的长期目标是更深入地了解受体-配体接合的物理过程，这些过程在先天免疫真菌识别过程中控制激活与逃避。我们在该项目中的中心假设是免疫原性细胞壁β-葡聚糖及其受体Dectin-1的纳米级组织为Dectin-1信号启动提供了机制基础，并且抗真菌剂的时空协调是实现充分Dectin-1应答的关键。我们预计，这项工作将提供机制洞察真菌病原体如何隐藏免疫原性配体，试图逃避检测和模式识别受体如何协调产生有效的先天免疫对念珠菌。基于以前的结果和我们强大的初步数据，我们将在三个具体目标中实现这一目标。在目标1中，我们将检验β 假丝酵母属物种中葡聚糖的“掩蔽”使该免疫原性配体的纳米级暴露几何结构最小化，以逃避免疫识别。我们的方法将涉及β-葡聚糖暴露的纳米级测量和测定，以评估β-葡聚糖暴露几何形状的功能意义。在目标2中，我们将检验以下假设：葡聚糖参与后的Dectin-1纳米结构域重排驱动了从调节磷酸酶中分离的纳米级分离过程，该过程通过脂质结构域分离来稳定。在目标3中，我们将检验甘露聚糖/DC-SIGN相互作用驱动信号传导的假设，该信号传导协调Dectin-1到宿主-病原体接触中的长距离主动转运。这种募集过程对于Dectin-1有效发现稀疏的葡聚糖暴露尤其重要，从而导致DC激活。该应用程序的特点是高分辨率成像技术和定量图像分析方法在传染病中的一个重要问题的创新应用。我们的研究将使该领域超越目前的真菌识别机制模型，这些模型受到缺乏纳米尺度信息的限制，从而能够更详细和准确地了解针对念珠菌属病原体的先天免疫的物理机制以及它们如何逃避免疫。该项目加入了PI在真菌免疫，膜生物物理学和定量荧光成像方面的专业知识，以及一个跨学科团队，该团队在表面制造方法，纳米生物学，数学和图像生物信息学方面提供了额外的专业知识。我们预计，我们的工作将通过在真菌免疫和新的治疗策略的新发现，从根本上推动该领域的发展。

 DESCRIPTION (provided by applicant): During innate immune recognition of Candida, the organization of cell wall ligands and pattern recognition receptors is an important determinant of successful immune activation. The long-term goal of our research is to achieve a deeper understanding of the physical processes of receptor-ligand engagement that govern activation vs. evasion during innate immune fungal recognition. Our central hypothesis in this project is that nanoscale organization of immunogenic cell wall β-glucan and its receptor Dectin-1 provides a mechanistic basis for Dectin-1 signal initiation, and that spatiotemporal orchestration of antifungal is key to achieving adequate Dectin-1 responses. We anticipate that this work will provide mechanistic insight into how fungal pathogens conceal immunogenic ligands in attempt to escape detection and how pattern recognition receptors are coordinated to generate effective innate immunity against Candida. Grounded in previous results and our strong preliminary data, we will pursue this objective in three Specific Aims. In Aim 1, we will test the hypothesis that β glucan "masking" in Candida species minimizes nanoscale exposure geometry of this immunogenic ligand to evade immune recognition. Our approach will involve nanoscopic measurements of β-glucan exposure and assays to assess the functional significance of β-glucan exposure geometry. In Aim 2, we will test the hypothesis that Dectin-1 nanodomain rearrangements upon glucan engagement drive a process of nanoscale segregation from regulatory phosphatases that is stabilized by lipid domain separation. In Aim 3, we will test the hypothesis that mannan/DC-SIGN interactions drive signaling that coordinates long-range active transport of Dectin-1 into host-pathogen contacts. This recruitment process is especially important for Dectin-1 to efficiently find sparse glucan exposures, leading to DC activation. This application features innovative application of high-resolution imaging technologies and quantitative image analytical methods to an important problem in infectious disease. Our studies will move the field beyond current models of fungal recognition mechanisms that are limited by lack of information on the nanoscopic scale, allowing a more detailed and accurate understanding of the physical mechanisms of innate immunity against Candida species pathogens and how they may evade immunity. This project joins the PI's demonstrated expertise in fungal immunity, membrane biophysics and quantitative fluorescence imaging together with an interdisciplinary team that brings additional expertise in surface fabrication methods, nanobiology, mathematics and image bioinformatics. We anticipate that our work will advance the field through fundamentally new discoveries in fungal immunity and new therapeutic strategies for Candidiasis.