Dual Function of VPO1 in Pathogen Recognition and Killing

VPO1在病原体识别和杀灭中的双重功能

• 批准号: 8536724
• 负责人: Guangjie Cheng
• 金额: $ 17.27万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8536724
• 关键词: Acids; Address; Animals; Bacteria; Bacterial Infections; Binding; Biological Process; Blood Circulation; Blood Vessels; Bromides; C2 Domain; Cardiovascular system; Catalytic Domain; Cell Wall; Chloride Ion; Chlorides; Communicable Diseases; Data; Defensins; Development; Diagnostic; Enzymes; Escherichia coli; Event; Family; Family member; Flagellin; Fluorescence Polarization; Foundations; Future; Generations; Genes; Heme; Host Defense; Hydrogen Peroxide; Immune; Immune response; Immune system; Immunoglobulin Domain; Immunoglobulins; Invaded; Lead; Length; Leucine; Lipopolysaccharides; Liver; Lung; Maintenance; Mediating; Methods; Microbe; Minnesota; Molecular; Molecular Cloning; Muramidase; N-Acetylmuramoyl-L-alanine Amidase; N-terminal; Natural Immunity; Oxidants; Pancreas; Pathway interactions; Pattern; Pattern recognition receptor; Peptidoglycan; Peroxidases; Phagosomes; Physiological; Play; Predisposition; Property; Proteins; Recombinant Proteins; Research; Role; Salmonella; Signal Transduction; Spleen; Staphylococcus aureus; Sterility; Surface Plasmon Resonance; System; Technology; Tertiary Protein Structure; Therapeutic; Toll-like receptors; Tretinoin; arm; base; heme a; human subject; insight; killings; lipoteichoic acid; loss of function mutation; member; microbial; microbicide; microorganism; mutant; neutrophil; novel; overexpression; pathogen; protein purification; receptor

DESCRIPTION (provided by applicant): Innate immunity is broadly defined as the first line of defense against invading pathogens. Innate immune recognition is classically mediated by the interaction of pattern-recognition receptors (PRRs) and pathogen-associated molecular patterns (PAMPs), triggering serial downstream signaling events; alternatively, a number of enzymes such as lysozyme, digestive enzymes and defensins indiscriminately kill bacteria when the enzyme encounters the microbes. In the latter case, the enzyme does not directly recognize microbes, and the elimination of invading microbes is non-specific. Whether there is a PRR to directly kill invading microorganisms remains to be elucidated. Vascular peroxidase 1 (VPO1) is a newly-discovered mammalian heme-containing peroxidase (hPx). VPO1 is unique among the members of hPx family in that it contains a catalytic domain at its C-terminus and a large N-terminal region including five leucine-rich regions (LRRs) and four immunoglobulin (Ig) C2 type domains. VPO1 is highly expressed in the cardiovascular system, lung, liver, pancreas and spleen, and is secreted into bloodstream at a 1000-fold higher concentration than is MPO. However, its biological function has not been established. The central hypothesis of this proposed research is that VPO1 can recognize and directly kill invading microbes. Our specific aims are to (1) determine whether the LRR and Ig C2 domains of VPO1 bind to PAMPs; (2) determine if the binding of VPO1, via LRR and Ig C2, mediates microbicidal activity via generation of hypohalous acids. The major methods for addressing the aims include molecular cloning and expressing, protein purification, fluorescence polarization technology and surface plasmon resonance technology. Successful completion of this proposal will: (1) provide novel insights into innate immune responses; (2) identify the first mammalian protein with dual functions of pathogen recognition and killing; (3) create a new paradigm in the maintenance of bloodstream sterility by the physiological action of a novel dual function hPx; (4) elucidate the molecular mechanisms of VPO1-mediated pathogen recognition and killing, setting the foundation for the future development of diagnostics and/or therapeutics involving this novel innate immune pathway.

描述（由申请人提供）：天生的免疫力广泛定义为针对入侵病原体的第一道防线。先天性免疫识别是通过模式识别受体（PRR）和与病原体相关的分子模式（PAMP）的相互作用的经典介导的，从而触发了串行的下游信号事件。另外，当酶遇到微生物时，许多酶，例如溶菌酶，消化酶和防御素不加可-Concy杀死细菌。在后一种情况下，酶不能直接识别微生物，并且消除入侵微生物是非特异性的。是否有PRR直接杀死入侵的微生物尚待阐明。血管过氧化物酶1（VPO1）是一种新发现的含血红素血红素的过氧化物酶（HPX）。 VPO1在HPX家族的成员中是独一无二的，因为它在其C末端包含一个催化域和一个大的N末端区域，包括五个富含亮氨酸的区域（LRR）和四个免疫球蛋白（Ig）C2型域。 VPO1在心血管系统，肺，肝，胰腺和脾脏中高度表达，并以比MPO高1000倍的浓度分泌到血液中。但是，尚未确定其生物学功能。这项拟议的研究的中心假设是VPO1可以识别并直接杀死入侵的微生物。我们的具体目的是（1）确定VPO1的LRR和Ig C2结构域是否与PAMP结合； （2）通过LRR和IG C2确定VPO1的结合是否通过产生低蓝糖酸会介导杀生活性。解决目标的主要方法包括分子克隆和表达，蛋白质纯化，荧光偏振技术和表面等离子体共振技术。该提案的成功完成将：（1）提供对先天免疫反应的新见解； （2）确定具有病原体识别和杀伤双重功能的第一个哺乳动物蛋白； （3）通过新型双重功能HPX的生理作用来维持血液不育的新范式； （4）阐明了VPO1介导的病原体识别和杀戮的分子机制，为诊断和/或疗法的未来开发奠定了基础，涉及这种新型的先天免疫途径。