Copper as a nutrient for Candida albicans at the host-pathogen interface

铜作为宿主-病原体界面白色念珠菌的营养物质

• 批准号: 8956111
• 负责人: Valeria C Culotta
• 金额: $ 46.74万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-05-01 至 2020-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8956111
• 关键词: Active Sites; Address; Animals; Antioxidants; Binding; Binding Proteins; Biology; Candida albicans; Charge; Communicable Diseases; Copper; Cu-Superoxide Dismutase; Disseminated candidiasis; Dose; Elements; Environment; Enzymes; Eukaryota; Event; Exposure to; Face; Family; Fluorescence Microscopy; Fluorescent Probes; Half-Life; Homeostasis; Human; Immune response; Immunity; Immunohistochemistry; Infection; Infectious Diseases Research; Integration Host Factors; Invaded; Ions; Kidney; Lesion; Leukocyte L1 Antigen Complex; Light; Manganese Superoxide Dismutase; Maps; Mediator of activation protein; Metabolism; Metals; Microbe; Microbial Biofilms; Micronutrients; Modeling; Monitor; Motion; Mus; Nutrient; Nutritional; Organ; Organism; Oxidative Stress; Pathogenesis; Pathway interactions; Process; Property; Proteins; Public Health; Publications; Reactive Oxygen Species; Reading; Recombinants; Research; Research Proposals; Resolution; Respiratory Burst; Roentgen Rays; Role; Site; Starvation; Structure; Superoxide Dismutase; Surface; System; Testing; Toxic effect; Virulence; Yeasts; Zinc deficiency; antimicrobial; assault; base; biological adaptation to stress; combat; deprivation; extracellular; fungus; in vivo; insight; kidney infection; macrophage; member; mouse model; mutant; neutrophil; novel; pathogen; public health relevance; response; trafficking

 DESCRIPTION (provided by applicant): Copper is a highly reactive element and based on its potential toxicity, animals use the deleterious properties of Cu in anti-microbial weaponry during infectious disease. Both bacterial and fungal pathogens are attacked with toxic doses of Cu inside the animal host. However, Cu is also an essential nutrient that microbes must acquire from the host. Currently, little is understood regarding host-pathogen competitions for Cu as a nutrient. To shed light into the biology of Cu during infectious disease, this research proposal focuses on Candida albicans, the most prevalent of human fungal pathogens. C. albicans requires Cu to maintain activity of a family of extracellular superoxide dismutase (SOD) enzymes that protect the yeast from the host oxidative burst and are important for virulence. Our findings show these Cu-SODs are unprecedented in structure and function in that they lack a Zn co-factor and contain a highly irregular open Cu site that may easily capture Cu from the host. We find the intracellular Cu-SOD of C. albicans is also remarkable in that this enzyme is replaced with a non-Cu alternative (Mn-SOD3) when the yeast is starved for Cu. This swapping of SOD enzymes is part of a large adaptation to Cu starvation, and surprisingly this Cu stress response becomes evident during C. albicans invasion of the kidney in vivo. To our knowledge this is the first documented evidence for host limitation of Cu during infection. We hypothesize that the host not only attacks pathogens with elevated Cu, but can also withhold this nutrient from invading microbes and C. albicans can adapt to both. Here we shall use the family of Cu SODs in C. albicans as a read-out for fungal Cu utilization during two extremes of host Cu availability, namely the high Cu of macrophages and the low Cu of kidney infection. The extracellular Cu-SODs become particularly important during fungal encounters with the oxidative burst of macrophages and we propose that C. albicans efficiently utilizes macrophage Cu to charge its SODs for an anti-oxidant defense. In Aim 1 (To define the metal binding properties and function of diverse SOD5-like proteins in C. albicans) we address the Cu binding capacities of the extracellular SODs as predictive indicators of how well these enzymes can maintain activity at the host-pathogen interface. Additionally we will explore the function of an unknown member of the extracellular SOD family, namely SOD6, as a potentially new Cu- requiring entity for fungal pathogenesis. In Aim 2 (To understand C. albicans utilization of host copper as a nutrient during macrophage infection), we examine activation of the extracellular fungal SODs in a macrophage infection model and define the pathway by which macrophage Cu is ultimately delivered to the active site of the fungal SOD enzymes. Lastly, Aim 3 (To understand the fungal Cu starvation response at the host-pathogen interface) will explore the kidney model of infection and define the mechanism whereby the host withholds Cu from C. albicans as the first documented nutritional immunity response involving Cu. Collectively, these studies promise to provide new insight into the implications for Cu as a nutrient for fungal pathogenesis.

 描述（由适用提供）：铜是一种高反应性元素，基于其潜在的毒性，动物在传染病期间使用Cu在抗微生物武器中使用的cu删除特性。细菌和真菌病原体都被动物宿主内部的有毒剂量o剂量攻击。但是，铜也是微生物必须从宿主那里获取的必不可少的营养。目前，关于CU作为营养素的宿主 - 病原体竞赛鲜为人知。为了阐明传染病期间CU的生物学，该研究提案的重点是白色念珠菌，它是人类真菌病原体中最普遍的念珠菌。白色念珠菌要求CU维持保护酵母免受宿主氧化爆发的细胞外超氧化物歧化酶（SOD）酶的活性，对病毒很重要。我们的发现表明，这些Cu-Sods在结构和功能上是前所未有的，因为它们缺少Zn Coactor，并且包含一个高度不规则的开放式CU位点，该位点很可能很容易从宿主那里捕获CU。我们发现白色念珠菌的细胞内CU-SOD也很了不起，因为当酵母菌饥饿的Cu饥饿时，该酶被非CU替代品（MN-SOD3）代替。 SOD酶的这种交换是对Cu饥饿的大型适应的一部分，令人惊讶的是，这种CU应激反应成为白色念珠菌入侵体内肾脏期间的证据。据我们所知，这是感染期间CU宿主限制的第一个证据。我们假设宿主不仅会攻击升高的CU病原体，而且还可以从入侵微生物中扣留这种营养素，而白色念珠菌可以适应两者。在这里，我们将使用白色念珠菌中的Cu Sod家族作为在两个极端的宿主Cu可用性期间的真菌Cu利用率的读出，即巨噬细胞的高铜和肾脏感染的低CU。在与巨噬细胞氧化物爆发的真菌相遇期间，细胞外Cu-Sods变得尤为重要，我们建议白色念珠菌有效利用巨噬细胞Cu为抗氧化剂防御量充电。在AIM 1（定义白色念珠菌中潜水SOD5样蛋白的金属结合特性和功能）中，我们解决了细胞外SOD的Cu结合能力，以此作为这些酶在宿主 - 肺病原子界面保持活性的预测指标。此外，我们将探索细胞外SOD家族的未知成员，即SOD6，作为真菌发病机理的潜在新的CU要求新的实体。在AIM 2（了解巨噬细胞感染期间白色念珠菌用作宿主铜作为营养素）中，我们检查了巨噬细胞感染模型中细胞外真菌SOD的激活，并定义了巨噬细胞CU最终传递到Fungal Sod enzymes活性位点的途径。最后，AIM 3（了解宿主 - 病原体界面处的真菌Cu饥饿反应）将探索感染的肾脏模型，并定义机制，从而将宿主从白色念珠菌中扣留CU作为第一个涉及Cu的首次记录的营养免疫反应。总的来说，这些研究有望提供对CU作为真菌发病机理的营养的新见解。