Defining the mechanism of lipid peroxidation in controlling Staphylococcus aureus infections

定义脂质过氧化控制金黄色葡萄球菌感染的机制

基本信息

批准号：
10301706
负责人：
William Norris Beavers
金额：
$ 16.13万
依托单位：
LOUISIANA STATE UNIV A&M COL BATON ROUGE
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-09-12 至 2024-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10301706
关键词：
Affinity Amino Acids Antibiotics Arachidonic Acids Automobile Driving Bacteria Biology Biotin Cell physiology Cells Cessation of life Chemicals Chemistry Development Drug resistance Enzymes Fatty Acids Future Harvest Human Immune In Vitro Infection Invaded Ions Kinetics Knowledge Lipid Peroxidation Lipids Measures Modification Molecular Mus Mutate Oxidants Oxidative Stress Oxides Pathogenesis Pathway interactions Pharmaceutical Preparations Phospholipids Polyunsaturated Fatty Acids Post-Translational Protein Processing Process Proteins Proteome Recombinants Respiration Role Scanning Sepsis Staphylococcus aureus Staphylococcus aureus infection Systemic infection Testing Therapeutic Therapeutic Intervention Tissues Toxic effect United States Validation antimicrobial bactericide design experimental study in vivo in vivo evaluation insight ketoaldehyde macromolecule mouse model mutant novel novel therapeutics pathogen resistant strain small molecule targeted treatment therapeutic development tool

Affinity Amino Acids Antibiotics Arachidonic Acids Automobile Driving Bacteria Biology Biotin Cell physiology Cells Cessation of life Chemicals Chemistry Development Drug resistance Enzymes Fatty Acids Future Harvest Human Immune In Vitro Infection Invaded Ions Kinetics Knowledge Lipid Peroxidation Lipids Measures Modification Molecular Mus Mutate Oxidants Oxidative Stress Oxides Pathogenesis Pathway interactions Pharmaceutical Preparations Phospholipids Polyunsaturated Fatty Acids Post-Translational Protein Processing Process Proteins Proteome Recombinants Respiration Role Scanning Sepsis Staphylococcus aureus Staphylococcus aureus infection Systemic infection Testing Therapeutic Therapeutic Intervention Tissues Toxic effect United States Validation antimicrobial bactericide design experimental study in vivo in vivo evaluation insight ketoaldehyde macromolecule mouse model mutant novel novel therapeutics pathogen resistant strain small molecule targeted treatment therapeutic development tool

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项目摘要

Project Summary Staphylococcus aureus infects every niche of the human host and is the leading cause of Gram-positive sepsis. There are over 900,000 severe S. aureus infections in the United States annually, emphasizing the need for new antibiotics to treat these infections. Understanding the molecular mechanisms used by the host to kill S. aureus and by S. aureus to defend against host killing will identify and validate novel targets for antimicrobial design. When the host encounters S. aureus, immune cells excrete various bactericidal small molecules. One class of bactericidal small molecules are polyunsaturated fatty acids, which are toxic to many bacterial species, but until recently the mechanism of toxicity was undefined. We discovered that arachidonic acid (AA), an abundant host polyunsaturated fatty acid, is bactericidal against S. aureus through a lipid peroxidation mechanism. AA is oxidized in S. aureus to a,b-unsaturated carbonyls and g-ketoaldehydes that are electrophilic, reacting with nucleophilic amino acids of the S. aureus proteome. Scavenging either oxidants that initiate lipid peroxidation or electrophiles generated through lipid peroxidation protects S. aureus from AA killing, confirming lipid peroxidation generated electrophiles as the bactericidal effectors of AA. Discovering the mechanism of AA toxicity against S. aureus is just the first step in identifying and validating lipid peroxidation as an antimicrobial strategy. We do not know the lipid electrophile species generated in S. aureus and what S. aureus proteins are targeted by electrophiles. We also do not know the S. aureus processes that produce the oxidants responsible for initiating lipid peroxidation or the identity of the oxidants produced in S. aureus. Finally, we do not know the specific host niches where lipid peroxidation is bactericidal or which host niches are most promising to test lipid peroxidation as an antimicrobial therapy. This proposal will expand the understanding of the bactericidal mechanisms of AA both in vitro and in vivo by testing three main hypotheses. In Aim 1, we will determine the lipid electrophile species and pathways of formation in S. aureus. This aim will test the hypothesis that oxidants derived from S. aureus respiration initiate lipid peroxidation resulting in a diverse array of bactericidal lipid electrophiles. In Aim 2, we will discover the protein targets of AA-derived lipid electrophiles in S. aureus. This aim will test the hypothesis that lipid electrophiles exert toxicity by disrupting enzymes in essential S. aureus processes through post-translational modification. In Aim 3, we will define the role of AA release in S. aureus pathogenesis. This aim will test the hypothesis that inhibiting host AA release results in increased S. aureus pathogenesis in a murine model of systemic infection and that the bactericidal role of AA will be different across the multiple host tissues tested. The insights gained from this proposal will further validate lipid peroxidation as an antimicrobial therapy, identify S. aureus proteins to target for antimicrobial development, and expand the understanding of the bactericidal role of AA in vivo.

项目摘要金黄色葡萄球菌感染了人类宿主的每个小众，是革兰氏阳性的主要原因败血症。每年在美国有超过900,000个严重的金黄色葡萄球菌感染，强调需要新的抗生素来治疗这些感染。了解宿主使用的分子机制杀死S.金黄色葡萄球菌和金黄色葡萄球菌以防御宿主杀人，将确定并验证新的目标抗菌设计。当宿主遇到金黄色葡萄球菌时，免疫细胞排泄各种杀菌小分子。一类杀菌小分子是多不饱和脂肪酸，对许多人有毒细菌种类，但直到最近，毒性机制仍未定义。我们发现那蛛网酸（AA）是一种丰富的宿主多不饱和脂肪酸，通过脂质对金黄色葡萄球菌是杀菌性的过氧化机制。 AA在金黄色葡萄球菌中被氧化为A，b-无饱和羰基和G-酮醛是亲电的，与金黄色葡萄球菌的亲核氨基酸反应。清除任一氧化剂启动通过脂质过氧化产生的脂质过氧化或电生物可保护金黄色葡萄球菌免受AA的影响杀死，确认脂质过氧化产生的电力是AA的杀菌效应子。发现对金黄色葡萄球菌的AA毒性机制只是识别和验证脂质过氧化的第一步作为一种抗菌策略。我们不知道金黄色葡萄球菌和S. 金黄色葡萄球菌蛋白是由电力靶向的。我们也不知道产生的金黄色葡萄球菌过程负责引发脂质过氧化的氧化剂或金黄色葡萄球菌产生的氧化剂的身份。最后，我们不知道脂质过氧化为杀菌或宿主壁ni的特定宿主生态位最有希望的是将脂质过氧化作为一种抗菌治疗。该建议将扩大通过测试三个主要假设，了解体外和体内AA的杀菌机制。在AIM 1中，我们将确定金黄色葡萄球菌中的脂质电力物种和形成途径。这个目标检验以下假设，即源自金黄色葡萄球菌呼吸的氧化剂启动脂质过氧化导致脂肪杀菌脂质电力的多种阵列。在AIM 2中，我们将发现AA衍生脂质的蛋白质靶标金黄色葡萄球菌中的电力。该目标将检验以下假设：脂质电力通过破坏毒性基本金黄色葡萄球菌过程中的酶通过翻译后修饰。在AIM 3中，我们将定义 AA释放在金黄色葡萄球菌发病机理中的作用。这个目标将检验抑制主机AA释放的假设在全身感染的鼠模型中导致金黄色葡萄球菌发病机理增加，并杀菌在测试的多个宿主组织中，AA的作用将有所不同。从该提议中获得的见解将进一步验证脂质过氧化作为一种抗菌治疗，鉴定金黄色葡萄球菌蛋白靶向抗菌发育，并扩展对AA在体内杀菌作用的理解。