Ferroptosis as a Death Mechanism in Lung Injury - Project 2

铁死亡作为肺损伤的死亡机制 - 项目 2

• 批准号: 10399560
• 负责人: Valerian E Kagan
• 金额: $ 36.74万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-01-03 至 2024-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10399560
• 关键词: Acute; Acute Lung Injury; Acute Respiratory Distress Syndrome; Alveolar Macrophages; Animals; Apoptosis; Apoptotic; Arachidonate 15-Lipoxygenase; Bacterial Pneumonia; Biological Markers; Brain Diseases; Cardiolipins; Cell Death; Cell Death Signaling Process; Cells; Cessation of life; Chronic; Clinical; Complex; Cytoprotective Agent; Development; Environment; Epithelial; Epithelial Cells; Event; Evolution; Exposure to; Human; Hydrogen Peroxide; Immune; Immune response; Immunocompromised Host; Immunosuppression; Impairment; Individual; Inflammation; Innate Immune Response; Kidney Diseases; Lead; Lipid Peroxidation; Lipids; Liver diseases; Lung; Membrane; Mitochondria; Modeling; Molecular; Mus; Oxidation-Reduction; Oxidative Stress; Oxides; Pathogenesis; Pathogenicity; Pathway interactions; Patients; Phosphatidylethanolamine; Phospholipids; Play; Property; Protein Isoforms; Pseudomonas aeruginosa; Pseudomonas aeruginosa infection; Reaction; Reactive Oxygen Species; Reporting; Respiratory Tract Infections; Role; Sampling; Scaffolding Protein; Signal Transduction; Signaling Molecule; Testing; Virulence Factors; Virulent; Work; base; cell injury; design; epithelial injury; glutathione peroxidase; in vivo; inhibitor; lipidomics; lung injury; macrophage; mortality; novel; novel therapeutic intervention; novel therapeutics; oxidation; pathogen; pathogenic bacteria; peroxidation; predictive marker; prevent; programs; selenoenzyme; small molecule

In ARDS, bacterial pathogens damage host cells, activate innate immune responses, and create a pro-oxidant environment leading to cell death via one of the death programs. This Project will focus on a recently described death program, ferroptosis, realized via Fe-dependent activation of lipid peroxidation under conditions of deficiency of glutathione peroxidase 4 (GPX4), a seleno-enzyme uniquely capable of reducing phospholipid hydroperoxides. We identified 15-hydroperoxy-arachidonoyl-phosphatidylethanolamines (15-HOO-AA-PE) as specific lipid biomarkers of ferroptosis. We also discovered that complexes of 15-lipoxygenase (15LOX) with a scaffold protein, PEBP1, play the major role in generating 15-HOO-AA-PE signals. We divulged ferroptosis as a death program of the human pulmonary epithelium. Ferroptosis occurs in alternatively activated macrophages with low levels of NO•/iNOS, thus causing immuno-suppression. Unexpectedly, we discovered that a common Gram-negative pathogen, P. aeruginosa – that does not contain polyunsaturated phospholipid oxidation substrates– expresses 15LOX (pLoxA) which oxidizes host polyunsaturated PE, generates 15-HOO-AA-PE and causes ferroptosis in epithelial cells and macrophages independently of the endogenous host 15-LOX. Ferroptosis-inducing pLoxA was detected in clinical P. aeruginosa isolates from ARDS patients. 15-HOO-AA- PE were identified in the lung samples from severely immuno-compromised patients with ARDS. Thus, we postulate the existence of a vicious cycle whereby inflammation/oxidative stress driven ferroptosis supported by endogenous 15-LOX acts as the major contributor to immunosuppression that sets the stage for the secondary P. aeruginosa infection of immune-impaired lung and further enhancement of ferroptosis by exogenous bacterial pLoxA. We propose to design and use selective small molecule pLoxA inhibitors, which will act as anti-ferroptotic agents thus representing new classes of pulmonary protectors. Aim 1 will reveal and decipher pathogenic mechanisms through which reactions of phospholipid peroxidation catalyzed by isoforms of endogenous mammalian 15-LOX or exogenous bacterial pLoxA – in conditions of GPX4/GSH deficiency – lead to accumulation of hydroperoxy-phospholipids in murine lung epithelial cells (MLE) and alveolar macrophages and establish molecular identity and ferroptotic properties of these products. By using redox lipidomics we will identify and quantify 15-HOO-AA-PE biomarkers of ferroptosis in vivo using a two-hit model of immunosuppression. We will also employ iNOS KO animals exposed to P. aeruginosa to reveal the role of NO• as a regulator of pLoxA-driven AA-PE oxidation and ferroptotic death in the mouse lung vivo. In Aim 2, we will design and develop selective inhibitors of pLoxA regulating P. aeruginosa-driven ferroptosis in epithelia and macrophages as a new class of small-molecule cytoprotective agents preventing breach of the barrier and immunosuppression.

在ARDS中，细菌病原体破坏宿主细胞，激活先天免疫反应，并产生促氧化剂