Defining the role of Serratia marcescens nuclease in infection process

定义粘质沙雷氏菌核酸酶在感染过程中的作用

• 批准号: 10646829
• 负责人: Lydia M Bogomolnaya
• 金额: $ 7.4万
• 依托单位: MARSHALL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-02-06 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10646829
• 关键词: Address; Affect; Anatomy; Animal Model; Antibiotics; Bacteria; Bacterial Drug Resistance; Biological; Biology; Blood Circulation; Catheters; Cell Culture Techniques; Cells; Cessation of life; Clinical; Data; Development; Dialysis patients; Dose; Enzymes; Evaluation; Excision; Eye; Frequencies; Future; Goals; Gram-Negative Bacteria; Growth; HL-60 Cells; Healthcare; Hemodialysis; High Prevalence; Hospitals; Immune Evasion; Immune response; Infection; Kidney Failure; Knowledge; Mediating; Modeling; Morbidity - disease rate; Multi-Drug Resistance; Mus; Neutrophil Infiltration; Organism; Outcome; Pathogenesis; Patients; Peritoneal Dialysis; Peritonitis; Play; Positioning Attribute; Pre-Clinical Model; Predisposition; Process; Research; Resistance; Resolution; Role; SWR/J Mouse; Serratia; Serratia Infections; Serratia marcescens; Signal Transduction; Site; Surgical wound; System; Systemic infection; Testing; Time; Tissues; Urinary tract; Virulence Factors; World Health Organization; antimicrobial; endonuclease; experimental study; extracellular; in vivo; in vivo imaging; insight; intraperitoneal; mouse model; mutant; neutrophil; novel; nuclease; opportunistic pathogen; pathogen; pathogenic bacteria; priority pathogen; rational design; respiratory; spatiotemporal; sugar

Project Summary The emergence of bacterial drug resistance, especially in hospital settings, represents the next great challenge in healthcare. Serratia marcescens, the Gram-negative bacterial pathogen with intrinsic resistance to several classes of antibiotics, can cause infections with severe outcomes affecting multiple body sites. This bacterium is also associated with complications of peritoneal dialysis (PD) in patients with kidney failure. Importantly, Serratia-associated peritonitis accompanied by massive neutrophil infiltration was shown to have the highest nonresolution rate among episodes caused by Gram-negative bacteria, leading either to the death of the PD patient, or catheter removal and transfer to hemodialysis. The progress in our understanding of S. marcescens infections is hampered by the lack of reliable preclinical model, which represents a critical barrier to progress in the field. The current knowledge of strategies used by this opportunistic pathogen to colonize the mammalian host and to evade the immune response is not complete, and only a handful of virulence factors were identified to date. S. marcescens is known to secrete an array of hydrolytic enzymes, including sugar non-specific endonuclease; however, the biological role of this enzyme during infection has not been evaluated. In this proposal, we seek to establish a murine model to study the S. marcescens dynamic spread during intraperitoneal infection and to test a hypothesis that an extracellular S. marcescens enzyme nuclease plays a key role in bacterial escape from neutrophil extracellular traps (NETs) in this niche. In Aim 1 we will characterize the bioluminescent S. marcescens spread following intraperitoneal infection using in vivo imaging. In Aim 2 we will first evaluate the S. marcescens extracellular nuclease potential to degrade NETs in cultures of neutrophil-like cells, followed by infection study to determine the biological role of this enzyme in vivo. This proposal will advance current understanding of Serratia pathogenesis and provide insight into the bacterium’s strategy to avoid neutrophil-mediated clearance. Altogether, our experiments will establish a blueprint for future studies of other nuclease-producing pathogenic bacteria.

项目概要 细菌耐药性的出现，尤其是在医院环境中，代表着下一个 医疗保健方面的巨大挑战。粘质沙雷氏菌 (Serratia marcescens)，革兰氏阴性细菌病原体 对几类抗生素的内在耐药性，可能导致严重后果的感染 影响多个身体部位。这种细菌还与腹膜并发症有关 肾衰竭患者的透析（PD）。重要的是，沙雷氏菌相关性腹膜炎 伴有大量中性粒细胞浸润的不解决率最高 由革兰氏阴性菌引起的事件，导致帕金森病患者死亡， 或拔除导管并转移至血液透析。我们对 S 的理解取得了进展。 粘质杆菌感染因缺乏可靠的临床前模型而受到阻碍，该模型代表了 该领域取得进展的关键障碍。当前所使用的策略知识 机会性病原体定植于哺乳动物宿主并逃避免疫反应，这并不是 完整的，迄今为止只发现了少数毒力因子。粘质链球菌是已知的 分泌一系列水解酶，包括糖非特异性核酸内切酶；然而， 该酶在感染过程中的生物学作用尚未得到评估。在这个提案中，我们 寻求建立小鼠模型来研究 S. marcescens 的动态传播 腹膜内感染并检验细胞外粘质沙门氏菌酶的假设 核酸酶在细菌逃离中性粒细胞胞外陷阱（NET）的过程中发挥着关键作用 利基。在目标 1 中，我们将描述生物发光 S. marcescens 的传播特征： 使用体内成像进行腹膜内感染。在目标 2 中，我们将首先评估 S. marcescens 细胞外核酸酶有可能降解中性粒细胞样细胞培养物中的 NET，然后 感染研究以确定这种酶在体内的生物学作用。该提案将推进 目前对沙雷氏菌发病机制的了解并提供对该细菌策略的深入了解 以避免中性粒细胞介导的清除。总而言之，我们的实验将为 其他产生核酸酶的致病细菌的未来研究。