Structure-function studies on IL-18, IL-18 binding proteins and receptors

IL-18、IL-18 结合蛋白和受体的结构功能研究

• 批准号: 7741600
• 负责人: Junpeng Deng
• 金额: $ 34.48万
• 依托单位: OKLAHOMA STATE UNIVERSITY STILLWATER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7741600
• 关键词: Adopted; Affinity; Agonist; Amino Acid Sequence; Autoimmune Process; Binding; Biochemical; Biological Assay; Bioterrorism; Bypass; Cell surface; Cells; Cellular biology; Collection; Communicable Diseases; Complex; Cowpox; Crohn' s disease; Crystallography; Cytokine Receptors; Development; Dimensions; Dimerization; Disease; Down-Regulation; Extracellular Domain; Family; Feedback; Goals; Homologous Gene; Host Defense; Human; IL18 gene; Immune response; Immunotherapy; In Vitro; Inflammatory; Interleukin-1; Interleukin-1 Receptors; Interleukin-18; Knowledge; Lead; Ligand Binding; Malignant Neoplasms; Mediating; Medical; Methods; Microbe; Modeling; Molecular; Molluscum contagiosum virus; Mouse Pox Virus; Mutagenesis; Pathogenesis; Pathway interactions; Physiological; Play; Positioning Attribute; Poxviridae; Proteins; Receptor Activation; Recruitment Activity; Research; Resolution; Rheumatoid Arthritis; Role; Septic Shock; Signal Transduction; Site-Directed Mutagenesis; Smallpox; Smallpox Viruses; Structure; Surface Plasmon Resonance; Surface Properties; Therapeutic; Variant; Viral; Virus Diseases; base; combat; cytokine; design; human disease; in vivo; inhibitor/antagonist; insight; interleukin-18 binding protein; interleukin-18 receptor; molecular recognition; mutant; novel therapeutics; protein complex; public health relevance; receptor; receptor binding

DESCRIPTION (provided by applicant): Interleukin-18 (IL-18) is a pro-inflammatory cytokine that belongs to the interleukin-1 (IL-1) superfamily. It plays an important role in host defense against microbes but also contributes to pathogenesis of several inflammatory diseases, including rheumatoid arthritis, septic shock and Crohn's disease. IL-18 signaling is initiated by its cell-surface binding to the receptor (IL-18R) alpha subunit, followed by the recruitment of the receptor beta subunit to form a ternary signaling complex. IL-18 activities are regulated in vivo by a naturally occurring antagonist, the IL-18 binding protein (IL-18BP) through a negative feedback mechanism. Poxviruses, including the smallpox (variola) virus, also express functional IL-18BP homologues to evade IL-18-mediated host immune responses. IL-18, IL-18R and IL-18BP are therefore attractive targets for developing therapeutics agonist inflammatory or infectious diseases where down- or up-modulating IL-18 activities is indicated. However, there is a lack of thorough understanding of how IL-18 activates its receptor and how IL-18BP inhibits IL-18. We propose to determine the crystal structures of various protein complexes of IL-18 with IL-18R or IL-18BP and perform functional studies based on the structural information. In addition, we will perform structure-based design of IL-18 variants that may either serve as a more effective cytokine capable of evading the neutralization of poxvirus IL-18BPs, or as a receptor antagonist capable of blocking IL-18 activities. Aim 1. To determine the molecular mechanism by which IL-18BPs neutralize IL-18. Aim 2. To determine the molecular mechanism by which IL-18 specifically recognizes 1 subunit of IL-18R. Aim 3. To determine the molecular mechanism by which IL-18 triggers the hetero-dimerization of IL-18R1 and 2 subunits. The objective of this application is the detailed characterization of a collection of IL-18 complexes by a combination of biophysical and biochemical methods, including x-ray crystallography, Surface Plasmon Resonance (SPR) and IL-18 bioassay. Accomplishing this objective is an important first step for achieving our long-term goal of understanding how IL-18 activates its receptors to initiate cell signaling and how this activity is regulated by IL-18BP.This research obtains/assumes extra dimensions. Since the targeted proteins are of significant medical relevance, our studies will provide a platform for designing selective inhibitors that may ultimately be developed into new therapeutics against a number of human diseases. Public Health Relevance: Our contribution here is expected to provide detailed molecular recognition of IL-18 by IL-18BP and IL-18R. This contribution is significant because it will fill the gap of our current knowledge on IL-18 activation pathway, and will provide important clues on how to modulate IL-18 activity. It may benefit efforts in developing treatments against some autoimmune and inflammatory diseases, in developing immunotherapies against other infectious diseases and cancer and in combating bioterrorism.

描述（由申请人提供）：白介素-18（IL-18）是属于白介素-1（IL-1）超家族的促炎细胞因子。它在宿主防御微生物中起着重要作用，但也有助于多种炎症性疾病的发病机理，包括类风湿关节炎，败血性休克和克罗恩病。 IL-18信号通过其细胞表面与受体（IL-18R）α亚基的结合引发，然后募集受体β亚基以形成三元信号传导复合物。 IL-18的活性通过自然发生的拮抗剂，即IL-18结合蛋白（IL-18BP）在体内调节，这是通过负反馈机制调节的。包括天花（Variola）病毒在内的痘病毒也表达功能性IL-18BP同源物，以逃避IL-18介导的宿主免疫反应。因此，IL-18，IL-18R和IL-18BP是开发疗法炎症或传染病的有吸引力的靶标，其中指示了降低或上调节IL-18活性。但是，缺乏对IL-18如何激活其受体以及IL-18BP抑制IL-18的受体的了解。我们建议确定IL-18与IL-18R或IL-18BP的各种蛋白质复合物的晶体结构，并根据结构信息进行功能研究。此外，我们还将对IL-18变体进行基于结构的设计，这些设计可能是能够避免吞噬痘病毒IL-18bps中和的更有效的细胞因子，或者是能够阻止IL-18活性的受体拮抗剂。目的1。确定IL-18bps中和IL-18的分子机制。目标2。确定IL-18特异性识别1个IL-18R亚基的分子机制。目的3。确定IL-18触发IL-18R1和2个亚基的异二分化的分子机制。该应用的目的是通过结合生物物理和生化方法的组合（包括X射线晶体学，表面等离子体共振（SPR）和IL-18生物测定法）的组合来详细表征IL-18复合物的详细表征。实现这一目标是实现我们的长期目标的重要第一步，即了解IL-18如何激活其受体以启动细胞信号传导以及如何通过IL-18BP调节该活性。这项研究获得/假定额外的维度。由于靶向蛋白具有重要的医学相关性，因此我们的研究将为设计选择性抑制剂提供一个平台，这些抑制剂最终可能会针对许多人类疾病发展为新的疗法。公共卫生相关性：我们这里的贡献有望提供IL-18BP和IL-18R对IL-18的详细分子识别。这种贡献很重要，因为它将填补我们当前在IL-18激活途径的知识的空白，并将提供有关如何调节IL-18活性的重要线索。它可能有益于开发针对某些自身免疫性和炎症性疾病的治疗方法，以开发针对其他传染病和癌症以及对抗生物恐怖主义的免疫疗法。