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（由申请人提供）：胆固醇依赖性溶细胞素（CDC）是一大类成孔毒素，有助于许多革兰氏阳性病原菌的发病机制。我们对 CDC 成孔机制的研究使人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膜孔组装的新范例。这些研究使我们能够合理地设计一种基于 CDC 的肺炎链球菌疫苗，目前盖茨基金会正在其肺炎链球菌疫苗工作中使用该疫苗。此外，我们对 CD59 结合 CDC 的发现使其他人能够开发出一种可能的专门针对 HIV 的治疗方法。在当前的更新中，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 如何启动孔隙形成将有助于我们设计专门针对其功能所需的高度敏感结构成分的疗法或改进的疫苗。我们还将继续研究疾病预防控制中心对胆固醇的膜识别。我们的研究揭示了 CDC 与胆固醇相互作用的一个显着方面：一些 CDC 可以与大量的膜胆固醇结合，其中只有一小部分支持孔的形成。看来，在不支持孔形成的位点将大部分单体与胆固醇结合的能力对于特定的 CDC 功能可能很重要。最近的研究表明，化脓性链球菌的 CDC 链球菌溶血素 O (SLO) 通过不依赖孔的机制将特定蛋白质转运到真核细胞中。这些研究表明，CDC 的孔独立效应可能是 CDC 促进发病机制的一个重要但尚未探索的机制。了解 CDC 如何与膜胆固醇结合而不触发孔形成，将揭示 CDC 如何在分子水平上发挥作用以及它们如何促进发病机制的新范例。最后，我们将利用对CDC机制的深刻理解，启动对膜攻击复合物/穿孔素（MACPF）家族蛋白的成孔机制的研究。 MACPF 蛋白分布广泛，有助于哺乳动物的免疫防御和引起原核和真核病原体的疾病。最近对 MACPF 蛋白的结构研究以及我们对 CDC 的工作促使其他人推测 MACPF 成孔机制表现出 CDC 成孔机制的特征，可能是由于两个蛋白质家族的共同起源所致。我们将利用我们与 CDC 的专业知识来启动 MACPF 蛋白分子机制的研究，以检验这一假设。我们预计 MACPF 成孔机制的研究将成为研究其他 MACPF 蛋白的基础，这些蛋白在免疫防御（补体膜攻击复合物）、发育（星形肽）、由真核病原体（如弓形虫）引起的疾病中发挥重要作用。疟疾和肿瘤破坏（穿孔素）。 公共卫生相关性：胆固醇依赖性溶细胞素 (CDC) 和膜攻击复合物/穿孔素 (MACPF) 蛋白是参与免疫防御 (MACPF) 的蛋白质大家族，并且是真核生物 (MACPF) 和原核生物（CDC 和 MACPF）的致病因子）病原体。我们对这些蛋白质的基本机制的研究将使我们能够更好地了解它们对细菌和真核病原体引起的疾病的贡献，以及免疫防御，从而更好地了解和治疗各种传染性和先天性疾病。