Overcoming nutritional immunity: Staphylococcal adaptation to host-imposed manganese and zinc starvation

项目摘要/摘要： 细菌感染是人类健康严重关切的问题，因为细菌感染的持续出现和 抗生素耐药性的传播。疾病控制中心和世界卫生组织的报告 都表示抗生素时代的结束即将到来。他们还呼吁开发新的 治疗金黄色葡萄球菌等细菌病原体的治疗策略。强有力的战略 宿主用来对抗入侵病原体的是对必需营养物质的限制，如锰 (锰)和锌(锌)。尽管在感染期间经历了锰和锌的饥饿，但金黄色葡萄球菌和其他 病原体仍然能够致病。阐明细菌如何适应这种宿主防御具有 有可能为治疗干预确定新的靶点，其破坏将增强 宿主的免疫反应。最近的研究表明，营养扣留的一个关键成分 应答是结合锰和锌的免疫效应蛋白钙保护素(CP)。这一发现使人类得以创造 一系列基于CP的新型试剂，可用于施加高度特定和生物相关的金属 文化中的饥饿。利用这些试剂发现，细菌的双组分信号转导 系统ArlRs是葡萄球菌对宿主施加的金属饥饿反应的关键调节因子。 令人惊讶的是，虽然已知ArlRs有助于葡萄球菌的毒力，但激活 系统以及系统的直接和间接目标是未知的。进一步的研究表明，锰 锌的封存阻止金黄色葡萄球菌利用糖而不是氨基酸作为能量来源。这 观察表明，锰和锌的饥饿扰乱了金黄色葡萄球菌的糖酵解。其他物种的最新研究进展 已经表明糖酵解可以依赖于这些金属。他们还透露，两个人的表达 推测依赖于锰的超氧化物歧化酶是金黄色葡萄球菌所特有的，它促进对宿主的抵抗力。 强制营养金属饥饿。总而言之，这些结果导致了金黄色葡萄球菌深刻改变了 它如何产生能量并表达替代酶以适应寄主施加的锰和锌 饿死了。这项建议的目的将评估这一假说，并阐明金黄色葡萄球菌如何适应MN。 和缺锌。目标一.阐明ArlRS监管网络的直接和间接目标以及 调节系统活动的环境信号。目的二.确定锰和锌的影响 饥饿对葡萄球菌中枢代谢和碳源偏好的影响。目标三.阐明金属如何 可得性影响苏打和苏打对葡萄球菌疾病的贡献。为了实现这些目标 利用微生物学和生物化学的技术以及 将利用先进的元素定量和全细胞顺磁光谱分析。

Project Summary/Abstract: Bacterial infections are of serious concern to human health because of the continued emergence and spread of antibiotic resistance. Reports by both the Centers for Disease Control and World Health Organization have stated that the end of the antibiotic era is upon us. They also called for the development of new therapeutic strategies for treating bacterial pathogens, such as Staphylococcus aureus. A powerful strategy utilized by the host to combat invading pathogens is the restriction of essential nutrients, such as manganese (Mn) and zinc (Zn). Despite experiencing Mn and Zn starvation during infection, S. aureus and other successful pathogens remain capable of causing disease. Elucidating how bacteria adapt to this host defense has the potential to identify new targets for therapeutic intervention, the disruption of which will enhance the efficacy of the host immune response. Recent work revealed that a critical component of the nutrient withholding response is the Mn- and Zn-binding immune effector protein calprotectin (CP). This finding allowed the creation of novel reagents based on CP that can be used to impose highly specific and biologically relevant metal starvation in culture. Utilizing these reagents revealed that the bacterial two-component signal transduction system ArlRS is a critical regulator of the staphylococcal response to host-imposed metal starvation. Surprisingly, while ArlRS is known to contribute to staphylococcal virulence, the signal that activates the system and the direct vs. indirect targets of the system are unknown. Further investigations suggest that Mn and Zn sequestration prevents S. aureus from utilizing sugars, but not amino acids, as an energy source. This observation suggests that Mn and Zn starvation disrupts glycolysis in S. aureus. Recent work in other species has shown that glycolysis can be dependent on these metals. They also revealed that the expression of two putatively Mn-dependent superoxide dismutases, which is unique to S. aureus, promotes resistance to host- imposed nutrient metal starvation. In total, these results lead to the hypothesis that S. aureus profoundly alters how it generates energy and expresses alternative enzymes in order to adapt to host-imposed Mn and Zn starvation. The Aims of this proposal will evaluate this hypothesis and elucidate how S. aureus adapts to Mn and Zn starvation. Aim I. Elucidate the direct vs. indirect targets of the ArlRS regulatory network and the environmental signals that modulate activity of the system. Aim II. Determine the impact of Mn and Zn starvation on staphylococcal central metabolism and carbon source preference. Aim III. Elucidate how metal availability impacts the contributions of SodA and SodM to staphylococcal disease. To accomplish these aims an interdisciplinary approach utilizing techniques taken from microbiology and biochemistry, as well as advanced elemental quantification and whole cell paramagnetic spectroscopy, will be utilized.