The Importance and Function of Heme Degrading Enzymes during Anthrax Disease

炭疽病期间血红素降解酶的重要性和功能

• 批准号: 9323699
• 负责人: ANTHONY W MARESSO
• 金额: $ 23.78万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-01-23 至 2018-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9323699
• 关键词: Alveolar; Alveolar Macrophages; Amino Acids; Animal Model; Anthrax disease; Antibiotics; Bacillus (bacterium); Bacillus anthracis; Bacteria; Bacterial Physiology; Basic Science; Binding; Biological; Biological Assay; Biological Models; Biology; Bioterrorism; Blood; Cell Survival; Cells; Cessation of life; Clinical; Complex; Data; Development; Disease; Disease Progression; Drug Metabolic Detoxication; Electrons; Enzymes; Experimental Models; Family; Funding; Gases; Genes; Gram-Positive Rods; Growth; Heme; Heme Iron; Hemoglobin; Homeostasis; Homologous Gene; Human; Infection; Iron; Knowledge; Laboratories; Left; Life; Lung; Measures; Mediating; Membrane Proteins; Modeling; N-terminal; Natural Immunity; Nutrient; Nutritional; Pathogenesis; Phase; Physiological; Process; Production; Property; Proteins; Publishing; RNAIII; Reaction; Role; Siderophores; Source; Staphylococcus aureus; Stress; Surface; System; Testing; Tissues; Virulence; Work; chemical property; combinatorial; extracellular; heme a; killings; macrophage; member; mutant; novel; pathogen; pathogenic bacteria; porphyrin a; response; uptake; weapons

Heme is a central molecule in the biology of life. Its unique chemical properties make it a versatile co-factor in many biological reactions. Heme is also an important source of iron for bacteria. In this regard, bacteria use surface proteins to import host heme and then break the heme ring to release the iron. This latter reaction is catalyzed by proteins termed heme degrading enzymes (HDEs). Because of their iron-liberating properties and the importance of iron in bacterial physiology, HDEs have emerged as critical during the infection of mammalian hosts. The sporulating bacterium B. anthracis is the causative agent of anthrax disease and a weapon of bioterrorism. This Gram-positive rod grows to extraordinary levels in vertebrate hosts and thus serves as a model for iron uptake. Previous work with this pathogen uncovered an elegant system of surface and secreted hemophores that import host heme. The biological consequences of heme import in terms of the lifecycle of this pathogen have not been determined. Preliminary data presented here suggests B. anthracis encodes three distinct HDEs, all of which break down heme. This finding raises the interesting question as to why B. anthracis would require three seemingly redundant HDEs. It is proposed here that each HDE may be important during different phases of a developing B. anthracis infection. In Aim 1, an inhalational model of infection, the most serious clinical form, is used to determine the contribution of each HDE to anthrax disease. In Aim 2, the functional role of each HDE is probed in three important host niches: protection from host killing by alveolar macrophages, the detoxification of excess heme, and the utilization of iron from host hemoglobin in blood. These studies will determine if HDEs are anti-anthrax targets and where in the bacillus infection cycle they function.

血红素是生命生物学中的核心分子。它独特的化学性质使它成为