Pore Formation by Cholesterol Dependent Cytolysins

胆固醇依赖性溶细胞素形成孔

• 批准号: 8121859
• 负责人: Rodney K. Tweten
• 金额: $ 43.01万
• 依托单位: UNIVERSITY OF OKLAHOMA HLTH SCIENCES CTR
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-04-01 至 2016-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8121859
• 关键词: Binding; Cholesterol; Complement; Complement Membrane Attack Complex; Contracts; Couples; Cytolysins; Development; Disease; Employee Strikes; Eukaryotic Cell; Event; Exhibits; Family; Foundations; Fruit; Future; HIV; Immune; Lead; Malaria; Mediating; Membrane; Methods; Modeling; Molecular; NAD+ Nucleosidase; Pathogenesis; Pathway interactions; Play; Pleurotus ostreatus; Pneumococcal vaccine; Population; Process; Prophylactic treatment; Protein Family; Proteins; Role; Route; Site; Solutions; Specificity; Streptococcus pneumoniae; Streptococcus pyogenes; Structure; Testing; Therapeutic; Toxin; Toxoplasma; Vaccines; Work; Xenorhabdus luminescens; base; design; improved; insight; intermolecular interaction; keratinocyte; monomer; mutant; pathogen; pathogenic bacteria; perforin; protein folding; streptolysin O; therapy design; tumor

DESCRIPTION (provided by applicant): The cholesterol-dependent cytolysins (CDCs) are a large group of pore-forming toxins that contribute to the pathogenesis of many Gram-positive pathogenic bacteria. Our studies of the CDC pore-forming mechanism have led to a better understanding of their role in pathogenesis and have revealed new paradigms for cellular recognition and assembly of a membrane pore. These studies enabled us to rationally design a CDC-based component vaccine for Streptococcus pneumoniae, which is currently being used by the Gates Foundation in their vaccine effort for S. pneumoniae. Also, our discovery of a CD59 binding CDC has allowed others to develop a possible therapeutic that specifically targets HIV. In the current renewal we will continue our studies into the CDC mechanism to understand the molecular events that trigger pore formation. Understanding how the CDCs initiate pore formation will help us design therapies or improved vaccines that specifically target highly sensitive structural components necessary for their function. We will also continue our studies into the membrane recognition of cholesterol by the CDCs. Our studies have revealed a remarkable aspect of the CDCs' interaction with cholesterol: some CDCs can bind to an expanded population of membrane cholesterol of which only a fraction supports pore formation. It appears that the ability to bind a significant fraction of monomers to cholesterol at sites that do not support pore formation may be important to specific CDC functions. It was recently shown that the CDC of Streptococcus pyogenes, streptolysin O (SLO), transports a specific protein into eukaryotic cells by a pore-independent mechanism. These studies suggest that pore- independent effects of the CDCs may be a significant, but unexplored, mechanism by which the CDCs contribute to pathogenesis. Understanding how CDCs can bind to membrane cholesterol without triggering pore formation will reveal new paradigms for how CDCs function at the molecular level and how they contribute to pathogenesis. Finally, we will leverage our deep understanding of the CDC mechanism to initiate studies into the pore forming mechanism of the membrane attack complex/perforin (MACPF) family of proteins. The MACPF proteins are widespread and contribute to mammalian immune defense and disease causing prokaryotic and eukaryotic pathogens. Recent structural studies of MACPF proteins and our work on the CDCs has prompted others to speculate that the MACPF pore forming mechanism exhibits features of the CDC pore forming mechanism, possibly resulting from a common origin of the two protein families. We will leverage our expertise with the CDCs to initiate studies into the molecular mechanism of the MACPF proteins to test this hypothesis. We expect the study of the MACPF pore forming mechanism will form the basis of a significant effort to investigate other MACPF proteins that play important roles in immune defense (complement membrane attack complex), development (astrotactins), diseases caused by eukaryotic pathogens such as Toxoplasma and malaria, and tumor destruction (perforin). PUBLIC HEALTH RELEVANCE: The cholesterol-dependent cytolysins (CDCs) and the membrane attack complex/perforin (MACPF) proteins are large families of proteins involved in immune defense (MACPF) and are pathogenic factors for eukaryotic (MACPF) and prokaryotic (CDCs and MACPF) pathogens. Our studies into the basic mechanism of these proteins will allow us to better understand their contribution to diseases caused by bacterial and eukaryotic pathogens, and immune defense that will lead to a better understanding of and therapies for a wide variety of infectious and congenital diseases.

描述(申请人提供)：胆固醇依赖的细胞溶血素(CDCs)是一大类形成毛孔的毒素，有助于许多革兰氏阳性病原菌的发病。我们对CDC成孔机制的研究使我们更好地了解了它们在发病机制中的作用，并揭示了细胞识别和组装膜孔的新范式。这些研究使我们能够合理地设计一种基于疾控中心的肺炎链球菌成分疫苗，盖茨基金会目前正在使用这种疫苗来接种肺炎链球菌。此外，我们发现了一种与CD59结合的CDC，这使得其他人能够开发出一种可能的针对HIV的治疗方法。在目前的更新中，我们将继续研究CDC机制，以了解触发孔隙形成的分子事件。了解CDC是如何启动毛孔形成的，将有助于我们设计专门针对其功能所需的高度敏感的结构成分的疗法或改进的疫苗。我们还将继续研究CDC对胆固醇的膜识别作用。我们的研究揭示了CDCs与胆固醇相互作用的一个显着方面：一些CDCs可以与扩大的膜胆固醇结合，其中只有一小部分支持孔形成。看来，在不支持孔形成的位置将相当一部分单体与胆固醇结合的能力可能对特定的CDC功能很重要。最近的研究表明，化脓性链球菌的CDC，即链球菌溶血素O(Streptolysin O，SLO)，通过一种孔不依赖的机制将一种特定的蛋白质转运到真核细胞中。这些研究表明，CDCs的孔非依赖性作用可能是CDCs参与发病机制的一个重要但尚未被探索的机制。了解CDCs如何在不触发孔形成的情况下与膜胆固醇结合将揭示CDCs如何在分子水平上发挥作用以及它们在发病机制中的作用的新范式。最后，我们将利用我们对CDC机制的深入理解来启动对膜攻击复合体/穿孔素(MACPF)家族蛋白质的成孔机制的研究。MACPF蛋白广泛存在于哺乳动物的免疫防御和引起原核生物和真核生物病原体的疾病中。最近对MACPF蛋白的结构研究和我们对CDC的研究促使其他人推测MACPF的成孔机制具有CDC成孔机制的特征，可能是由于这两个蛋白质家族的共同起源。我们将利用我们与疾控中心的专业知识来启动对MACPF蛋白分子机制的研究，以检验这一假设。我们预计，对MACPF孔形成机制的研究将为研究其他在免疫防御(补体膜攻击复合体)、发育(天星素)、弓形虫和疟疾等真核病原体引起的疾病以及肿瘤破坏(穿孔素)中发挥重要作用的MACPF蛋白奠定重要基础。 公共卫生相关性：胆固醇依赖的细胞溶血素(CDCs)和膜攻击复合体/穿孔素(MACPF)蛋白是参与免疫防御(MACPF)的蛋白大家族，是真核(MACPF)和原核(CDCs和MACPF)病原体的致病因子。我们对这些蛋白质的基本机制的研究将使我们更好地了解它们在细菌和真核病原体引起的疾病中的作用，以及免疫防御，这将导致更好地理解和治疗各种传染病和先天性疾病。