Nano and Microscale Molecular Machines for Innate Immune Sensing of Candida

 描述(申请人提供)：在念珠菌的天然免疫识别过程中，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-配体结合的物理过程，该过程控制着天然免疫真菌识别过程中的激活和逃避。我们在这个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信号的启动提供了一个机制基础，而抗真菌的时空协调是实现足够的Dectin-1反应的关键。我们预计，这项工作将为真菌病原体如何隐藏免疫原配体以逃避检测，以及模式识别受体如何协调以产生有效的天然免疫来对抗念珠菌提供机械洞察。根据以往的结果和我们强有力的初步数据，我们将在三个具体目标中实现这一目标。在目标1中，我们将测试β的假设 假丝酵母菌中的葡聚糖“掩蔽”最大限度地减少了这种免疫原配体的纳米级暴露几何形状，以逃避免疫识别。我们的方法将包括β-葡聚糖暴露的纳米测量和评估β-葡聚糖暴露几何形状的功能意义的分析。在目标2中，我们将检验这样的假设，即葡聚糖结合时Dectin-1纳米结构域的重排驱动了一个通过脂类结构域分离稳定的调节磷酸酶的纳米级分离过程。在目标3中，我们将测试假设，甘露聚糖/DC-SIGN相互作用驱动信号，协调Dectin-1的远程活性运输进入宿主-病原体接触。这一招募过程对于Dectin-1有效地发现稀疏的葡聚糖暴露，导致DC激活尤为重要。这一应用的特点是创新地应用了高分辨率成像技术和定量图像分析方法来解决传染病中的一个重要问题。我们的研究将使该领域超越目前的真菌识别机制模型，这些模型受到纳米尺度上缺乏信息的限制，使我们能够更详细和准确地了解针对念珠菌物种病原体的天然免疫的物理机制，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成熟专业知识，以及一个跨学科团队，该团队带来了表面制造方法、纳米生物学、数学和图像生物信息学方面的更多专业知识。我们预计，我们的工作将通过真菌免疫方面的根本性新发现和念珠菌病的新治疗策略来推动该领域的发展。

 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.