Adaptation of Staphylococcus aureus to Mn and Zn starvation imposed by the host

金黄色葡萄球菌对宿主造成的锰和锌饥饿的适应

• 批准号: 8814169
• 负责人: Thomas Everett Kehl-Fie
• 金额: $ 10.51万
• 依托单位: UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-03-01 至 2016-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8814169
• 关键词: Abscess; Affinity; Amino Acids; Antibiotic Resistance; Bacteria; Bacterial Infections; Binding; Biology; C57BL/6 Mouse; Carbon; Collaborations; Communities; Counseling; Development; Disease; Environment; Enzymes; Faculty; Foundations; Future; Glycolysis; Goals; Graduate Degree; Growth; Host Defense; Human body; Immunity; Individual; Infection; Institution; Invaded; Investigation; Ions; Kinetics; Laboratories; Leukocyte L1 Antigen Complex; Manganese; Mediating; Medical; Metals; Methicillin Resistance; Microbiology; Modeling; Molecular; Morbidity - disease rate; Mus; Nosocomial Infections; Nutrient; Nutritional; Oxidative Stress; Pathogenesis; Pathway interactions; Pattern; Positioning Attribute; Postdoctoral Fellow; Process; Proteins; Regulation; Regulon; Research; Research Personnel; Resistance; Role; Running; S100A8 gene; S100A9 gene; Senior Scientist; Site; Source; Staphylococcal Infections; Staphylococcus aureus; Starvation; Stress; Superoxide Dismutase; Superoxides; System; Systemic disease; Technology; Testing; Time; Universities; Variant; Vertebrates; Virulence; Virulent; Washington; Work; Zinc; base; burden of illness; career; career development; combat; follow-up; insight; killings; microbial; mortality; mutant; neutrophil; novel therapeutics; pathogen; post-doctoral training; preference; prevent; programs; response; skills; soft drink; stressor; sugar; transcriptome sequencing; zinc-binding protein

DESCRIPTION (provided by applicant): Bacterial infections are of substantial global concern due to increasing antibiotic resistance. Staphylococcus aureus is a pathogen of alarm because of the ability of the bacterium to infect nearly every site in the human body. This adaptability combined with increasing antibiotic resistance results in the high levels of morbidity and mortality associated with staphylococcal infections. A powerful strategy utilized by vertebrates to combat bacterial pathogens is the sequestration of essential nutrients, a process known as nutritional immunity. Recent work found that during invasive staphylococcal disease mature abscesses are virtually devoid of manganese (Mn) and zinc (Zn). Further work revealed that the sequestration of Mn during staphylococcal infection is dependent on the neutrophil protein calprotectin (CP), a heterodimer of S100A8 and S100A9. CP is capable of binding one Mn ion and two Zn ions with nanomolar affinity, suggesting a role not only in Mn withholding but also in Zn sequestration. In a murine model of infection, CP-deficient mice have increased staphylococcal burdens, indicating that S. aureus is Mn starved during infection. This idea is further supported by the observation that during infection Mn-dependent bacterial processes are inhibited. In total, these results suggest that vertebrates cause S. aureus to become Mn and Zn starved during infection and that this starvation is critical to host defense. Even though vertebrates create an environment virtually devoid of Mn and Zn, S. aureus remains capable of causing significant and devastating disease. These observations led to the hypothesis that S. aureus must somehow adapt to the Mn and Zn limitation imposed by the host. S. aureus is known to encode dedicated Mn and Zn transporters that may help this pathogen resist the effects of vertebrate metal sequestration. However, the increased staphylococcal virulence in CP-deficient mice suggests that expression of Mn transporters, and presumably Zn transporters, by S. aureus is not sufficient to prevent metal starvation. Although it is known that vertebrates sequester Mn and Zn, the kinetics of this process have not been elucidated, and the extent of metal starvation imposed on S. aureus remain unknown. Furthermore, how S. aureus resists and adapts to Mn and Zn starvation imposed by CP remains unclear. Current projects are focused on elucidating the timing of Mn and Zn sequestration, the bacterial processes that are disrupted by this host defense, and the contribution of dedicated Mn and Zn import systems to resisting CP. Once a faculty position has been obtained, investigations will focus on determining how S. aureus adapts to Mn and Zn starvation. The work proposed in this application will follow up on the observations that the ArlRS two-component regulatory system and the two Mn-dependent superoxide dismutases expressed by S. aureus promote resistance to host imposed Mn and Zn limitation. The Specific Aims of this proposal are as follows: Aim I. Evaluate the role of ArlRS regulation and alterations in carbon source preference to facilitating S. aureus adaptation to host-imposed Mn and Zn limitation. Aim II. Determine the individual roles of S. aureus superoxide dismutases in resisting host-imposed metal starvation. In addition to providing substantial insight into the mechanisms that S. aureus uses to evade an important host defense, this proposal will facilitate the development of my independent research career. My long-term goal is to understand how the interactions between host and pathogen influence disease development. In pursuit of this goal, I obtained my graduate degree from Washington University in St. Louis with an emphasis in Molecular Microbiology and Microbial Pathogenesis followed by postdoctoral training in staphylococcal pathogenesis and metals biology with Dr. Eric Skaar at Vanderbilt University. My immediate goal is to obtain a faculty position and establish a highly productive independent research program. The commitment of Vanderbilt University to postdoctoral training, which includes offering seminars on how to run a successful independent laboratory, has substantially enhanced my ability to achieve this goal. To promote a successful transition from postdoctoral fellow to independent investigator, I will seek out advice and counsel from senior scientists at my future institution and an established network of informal advisors. I will also actively pursue opportunities to develop skills that will facilitate running a successful independent laboratory, and cultivate new collaborations. In combination, the proposed investigations and career development activities will provide an excellent foundation for the development of an independent research program.

描述（由申请人提供）：由于抗生素耐药性不断增加，细菌感染已成为全球关注的焦点。金黄色葡萄球菌是一种值得警惕的病原体，因为该细菌几乎能够感染人体的每个部位。这种适应性与不断增加的抗生素耐药性相结合，导致与葡萄球菌感染相关的高发病率和死亡率。脊椎动物利用的强大策略 对抗细菌病原体的方法是封存必需营养素，这一过程称为营养免疫。最近的研究发现，在侵袭性葡萄球菌疾病期间，成熟脓肿实际上不含锰 (Mn) 和锌 (Zn)。进一步的研究表明，葡萄球菌感染期间 Mn 的封存依赖于中性粒细胞蛋白钙卫蛋白 (CP)，它是 S100A8 和 S100A9 的异二聚体。 CP 能够以纳摩尔亲和力结合一个 Mn 离子和两个 Zn 离子，表明其不仅在 Mn 保留中发挥作用，而且在 Zn 螯合中也发挥作用。在小鼠感染模型中，CP缺陷小鼠的葡萄球菌负荷增加，表明金黄色葡萄球菌在感染期间处于锰饥饿状态。这一观点得到了感染期间依赖于锰的细菌过程受到抑制的观察结果的进一步支持。总的来说，这些结果表明脊椎动物导致金黄色葡萄球菌在感染过程中出现锰和锌饥饿，并且这种饥饿对于宿主防御至关重要。尽管脊椎动物创造了一个几乎没有锰和锌的环境，但金黄色葡萄球菌仍然能够引起严重的毁灭性疾病。这些观察结果得出这样的假设：金黄色葡萄球菌必须以某种方式适应宿主施加的锰和锌限制。已知金黄色葡萄球菌编码专用的锰和锌转运蛋白，这可能有助于该病原体抵抗脊椎动物金属封存的影响。然而，CP缺陷小鼠中葡萄球菌毒力的增加表明，金黄色葡萄球菌表达的锰转运蛋白（可能还有锌转运蛋白）不足以防止金属饥饿。尽管众所周知 脊椎动物会螯合锰和锌，但这一过程的动力学尚未阐明，金黄色葡萄球菌的金属饥饿程度仍然未知。此外，金黄色葡萄球菌如何抵抗和适应CP造成的锰和锌饥饿仍不清楚。目前的项目重点是阐明锰和锌螯合的时间、被宿主防御破坏的细菌过程，以及专用的锰和锌输入系统对抵抗CP的贡献。一旦获得教职，研究将集中于确定金黄色葡萄球菌如何适应锰和锌饥饿。本申请中提出的工作将跟进以下观察结果：ArlRS 双组分调节系统和金黄色葡萄球菌表达的两种 Mn 依赖性超氧化物歧化酶促进对宿主施加的 Mn 和 Zn 限制的抵抗力。该提案的具体目标如下： 目标 I. 评估 ArlRS 调节和碳源偏好改变对促进金黄色葡萄球菌适应宿主施加的 Mn 和 Zn 限制的作用。目标二。确定金黄色葡萄球菌超氧化物歧化酶在抵抗宿主施加的金属饥饿中的个体作用。除了提供对金黄色葡萄球菌用来逃避重要宿主防御的机制的深入了解之外，该提案还将促进我独立研究生涯的发展。我的长期目标是了解宿主和病原体之间的相互作用如何影响疾病的发展。为了实现这一目标，我在圣路易斯华盛顿大学获得了研究生学位，主修分子微生物学和微生物发病机制，随后在范德比尔特大学跟随 Eric Skaar 博士接受了葡萄球菌发病机制和金属生物学的博士后培训。我的近期目标是获得教职并建立一个高效的独立研究项目。范德比尔特大学对博士后培训的承诺，包括提供有关如何成功运营独立实验室的研讨会，大大增强了我实现这一目标的能力。为了促进从博士后研究员到独立研究者的成功过渡，我将向我未来所在机构的资深科学家以及已建立的非正式顾问网络寻求建议和建议。我还将积极寻求发展技能的机会，以促进 运营一个成功的独立实验室，并培养新的合作。结合起来，拟议的调查和职业发展活动将为独立研究项目的发展提供良好的基础。