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)：由于抗生素耐药性的增加，细菌感染是全球关注的重大问题。金黄色葡萄球菌是一种令人警觉的病原体，因为这种细菌几乎可以感染人体的每一个部位。这种适应性加上不断增加的抗生素耐药性，导致了与葡萄球菌感染相关的高发病率和死亡率。脊椎动物利用的一种强大的策略 对抗细菌病原体是隔离必要的营养物质，这一过程被称为营养免疫。最近的研究发现，在侵袭性葡萄球菌病期间，成熟脓肿实际上缺乏锰(Mn)和锌(Zn)。进一步的研究表明，葡萄球菌感染过程中锰的隔离依赖于中性粒细胞蛋白钙保护素(CP)，它是S100A8和S100A9的异源二聚体。CP能以纳摩尔亲和力结合1个锰离子和2个锌离子，表明CP不仅具有截留锰的作用，而且还具有固着锌的作用。在小鼠感染模型中，CP缺乏的小鼠增加了金黄色葡萄球菌的负担，表明金黄色葡萄球菌在感染期间缺乏锰。在感染期间，依赖锰的细菌过程受到抑制，这一观察进一步支持了这一观点。总而言之，这些结果表明，脊椎动物导致金黄色葡萄球菌在感染期间缺乏锰和锌，这种饥饿对宿主防御至关重要。即使脊椎动物创造了一个几乎没有锰和锌的环境，金黄色葡萄球菌仍然能够引起重大和毁灭性的疾病。这些观察结果导致了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的假设。已知金黄色葡萄球菌编码专门的锰和锌转运蛋白，这可能有助于这种病原体抵抗脊椎动物金属隔离的影响。然而，金黄色葡萄球菌对CP缺乏小鼠的毒力增加表明，金黄色葡萄球菌表达的锰转运体和可能的锌转运体不足以防止金属饥饿。虽然大家都知道 脊椎动物将锰和锌隔离，这一过程的动力学尚未阐明，对金黄色葡萄球菌造成金属饥饿的程度也尚不清楚。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。目前的工作主要集中在阐明锰和锌的隔离时间，被这种寄主防御所扰乱的细菌过程，以及专用的锰和锌输入系统在抵抗CP中的作用。一旦获得教员职位，调查将集中于确定金黄色葡萄球菌如何适应锰和锌的饥饿。本申请中提出的工作将跟踪观察到的观察结果，即ArlRS双组分调控系统和金黄色葡萄球菌表达的两个依赖于锰的超氧化物歧化酶促进了对寄主施加的锰和锌限制的抗性。本建议的具体目的如下：目的1.评估ArlRs调控和碳源偏好的改变在促进金黄色葡萄球菌适应宿主施加的锰和锌限制方面的作用。目的II.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实质性洞察外，这项建议还将促进我独立研究事业的发展。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。为了追求这一目标，我在圣路易斯的华盛顿大学获得了研究生学位，重点是分子微生物学和微生物病理学，随后在Vanderbilt大学跟随Eric Skaar博士进行了葡萄球菌致病机理和金属生物学的博士后培训。我的近期目标是获得一个教员职位，并建立一个富有成效的独立研究项目。范德比尔特大学对博士后培训的承诺，包括提供关于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。为了促进从博士后到独立研究员的成功过渡，我将向我未来机构的资深科学家和建立的非正式顾问网络寻求建议和建议。我还将积极寻找机会发展技能，以促进 办好独立实验室，培养新的合作伙伴。结合起来，拟议的调查和职业发展活动将为独立研究计划的发展提供良好的基础。