Functional assessment of TprC/D and TprK proteins of syphilis causing spirochete, Treponema pallidum

梅毒螺旋体、梅毒螺旋体 TprC/D 和 TprK 蛋白的功能评估

• 批准号: 10477191
• 负责人: Nikhat Parveen
• 金额: $ 23.55万
• 依托单位: RUTGERS BIOMEDICAL AND HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10477191
• 关键词: AIDS prevention; Achievement; Adherence; Adhesions; Adopted; Affect; Amino Acids; Antibodies; Antigenic Variation; Antigens; Bacterial Adhesins; Bacterial Outer Membrane Proteins; Binding; Binding Proteins; Biological Assay; Biological Process; Biology; Borrelia burgdorferi; Cardiovascular system; Cell Line; Cells; Coculture Techniques; Data; Disease; ECM receptor; Electrophysiology (science); Engineering; Epithelial Cells; Extracellular Matrix; Family; Focal Infection; Funding; Future; Genetic; Glioma; Globus Pallidus; Goals; HIV; Homologous Gene; Human; Immune Evasion; In Vitro; Individual; Infection; Intake; Label; Lead; Lipid Bilayers; Lipids; Lyme Disease; Measures; Mediating; Membrane; Membrane Proteins; Molecular; Neurologic; Nucleotides; Nutrient; Oligosaccharides; Order Spirochaetales; Oryctolagus cuniculus; Pathogenesis; Pathway interactions; Peptide Hydrolases; Peptides; Persons; Physiological; Prevalence; Property; Protein Family; Proteins; Public Health; Recombinants; Research; Role; Specificity; Structural Models; Structure; Surface; Syphilis; System; Systemic disease; Testing; Treponema denticola; Treponema pallidum; United States; VDAC1 gene; Vaccines; Variant; Virulence Factors; base; cell type; combinatorial; comparative genomics; disease transmission; experimental study; extracellular; gain of function; genetic manipulation; high risk; immunogenic; improved; in vivo; laboratory rabbit; major outer membrane protein; member; mutant; novel strategies; oral pathogen; pathogen; prevent; protein K; protein function; receptor; reconstitution; tool; transmission process; uptake; vaccine candidate; vector

SCIENTIFIC ABSTRACT Syphilis has an estimated global prevalence of 36M cases, with more than 11M new infections occurring per year around the world. In the United States alone, the number of cases of infectious syphilis has steadily increased since 2000, indicating that this disease is still a public health concern, particularly considering that it can lead to serious neurological and cardiovascular sequelae. Understanding the biological function of the outer membrane proteins (OMPs) of the syphilis agent, Treponema pallidum subsp. pallidum (T. pallidum), is one of the greatest challenges in the study of syphilis pathogenesis. Progress towards functional characterization of OMPs is hindered by the lack of an independent, pure culture system for T. pallidum, genetic intractability of the pathogen, the need to use of rabbits for bacterial propagation, the paucity of OMPs in T. pallidum outer membrane, and the fragility of this cellular compartment. Despite so many limitations, undertaking the study of T. pallidum OMPs can greatly enhance our understanding of the role of these virulence factors in syphilis pathogenesis and even provide important clues on new approaches to successfully control syphilis, such as by developing a protective vaccine. Twelve of putative OMPs/virulence factors belong to the T. pallidum repeat (Tpr) family, which are a group of highly immunogenic proteins predicted to be homologous to the Treponema denticola (T. denticola) major sheath protein (Msp), a surface virulence factor with porin and adhesin properties. Limited or no experimental evidence is available until now regarding functions of various Tprs. Based on homology to Msp, structural models for the Tprs and our preliminary data, we hypothesize that several Tprs also have dual roles as adhesins and porin transporters. T. pallidum and Borrelia burgdorferi, which causes Lyme disease, are physiologically and structurally related spirochetes. Unlike T. pallidum, B. burgdorferi can be genetically manipulated and transformed to express selected Tprs as if they were constituents of its OM. The validity of the surrogate system to study Tprs is supported by our preliminary data showing that when TprD2 and TprK are expressed on the surface of a non-infectious and poorly adherent B. burgdorferi strain, these proteins enhance adhesion to Glioma and epithelial cells and facilitate amino acids and peptides uptake. Here, we plan to further test our hypothesis and establish function of these important virulence factors by using both our well- tried B. burgdorferi, as well as the T. denticola msp mutant surrogate systems. We will conduct following studies to test our hypothesis: (1) Determine whether T. pallidum TprC, D2, and K proteins mediate attachment to host cells in differential manner by recognizing the specific host receptors/ECM components on each cell type, and (2) Determine the role of T. pallidum TprC, D2, and K proteins as channels involved in nutrient transport. Significance: Our studies will lead to a better understanding of the molecular basis of T. pallidum adhesion to host components, which is a pivotal step in congenital transmission and neuroinvasion during infection and will provide important information to further support the use of these antigens as vaccine candidates in the future.

科学摘要 梅毒全球患病率估计为 3600 万例，新增感染病例超过 1100 万例 每年在世界各地。仅在美国，传染性梅毒病例数就一直在稳步上升 自 2000 年以来有所增加，表明这种疾病仍然是一个公共卫生问题，特别是考虑到它 可导致严重的神经和心血管后遗症。了解外部的生物学功能 梅毒病原体梅毒螺旋体亚种的膜蛋白 (OMP)。苍白球菌（T. pallidum），是其中之一 梅毒发病机制研究的最大挑战。功能表征的进展 OMPs 的发展受到阻碍，因为缺乏独立、纯的梅毒螺旋体培养系统、该菌的遗传难解性 病原体、需要使用兔子进行细菌繁殖、梅毒螺旋体外层中缺乏 OMP 膜，以及该细胞室的脆弱性。尽管有如此多的限制，进行研究 梅毒螺旋体 OMP 可以极大地增强我们对这些毒力因子在梅毒中的作用的理解 发病机制，甚至为成功控制梅毒的新方法提供重要线索，例如通过 开发保护性疫苗。十二个假定的 OMP/毒力因子属于梅毒螺旋体重复序列 (Tpr) 家族，是一组预计与密螺旋体同源的高免疫原性蛋白质 denticola (T. denticola) 主要鞘蛋白 (Msp)，一种具有孔蛋白和粘附素特性的表面毒力因子。 迄今为止，有关各种 Tpr 功能的实验证据有限或没有。基于 与 Msp、Tpr 的结构模型和我们的初步数据同源，我们假设几个 Tpr 还具有粘附素和孔蛋白转运蛋白的双重作用。梅毒螺旋体和伯氏疏螺旋体，导致 莱姆病是生理和结构上相关的螺旋体。与梅毒螺旋体不同，伯氏疏螺旋体可以 经过基因操纵和转化以表达选定的 Tpr，就好像它们是其 OM 的组成部分一样。这 我们的初步数据支持研究 Tprs 的替代系统的有效性，该数据表明当 TprD2 和 TprK 在非感染性且粘附性差的伯氏疏螺旋体菌株的表面表达，这些蛋白质 增强对胶质瘤和上皮细胞的粘附，促进氨基酸和肽的吸收。在这里，我们计划 进一步检验我们的假设并通过使用我们的良好方法建立这些重要毒力因子的功能 尝试了伯氏疏螺旋体以及 T. denticola msp 突变体替代系统。我们将进行以下研究 检验我们的假设：(1) 确定梅毒螺旋体 TprC、D2 和 K 蛋白是否介导与宿主的附着 通过识别每种细胞类型上的特定宿主受体/ECM 成分，以不同的方式识别细胞，以及 (2) 确定梅毒螺旋体TprC、D2 和K 蛋白作为参与营养物运输的通道的作用。 意义：我们的研究将有助于更好地理解梅毒螺旋体粘附于 宿主成分，这是感染过程中先天性传播和神经侵袭的关键步骤，将 提供重要信息以进一步支持未来使用这些抗原作为候选疫苗。