Virulence factors of periodontopathogens

牙周病原菌的毒力因子

• 批准号: 7811931
• 负责人: Janina P Lewis
• 金额: $ 13.24万
• 依托单位: VIRGINIA COMMONWEALTH UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-24 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7811931
• 关键词: Adult; Anaerobic Bacteria; Animal Model; Bacteria; Cardiovascular Diseases; Carrier Proteins; Cell Fraction; Chromosomes; Crystallography; Cytoplasm; Data; Diabetes Mellitus; Environment; Future; Gene Expression; Gene Expression Regulation; Generations; Genome; Genomics; Gram-Negative Anaerobic Bacteria; Growth; Health; Hemeproteins; Hemin; Homologous Gene; Iron; Knowledge; Light; Location; Low Birth Weight Infant; Mediating; Membrane; Metabolism; Molecular; Nutrient; Operon; Organism; Oxidative Stress; Periodontal Diseases; Play; Porphyromonas gingivalis; Positioning Attribute; Proteins; Regulation; Role; Source; Structure; Testing; Transcript; Virulence; Virulence Factors; Work; antimicrobial drug; defined contribution; design; genetic regulatory protein; haptoglobin-hemoglobin complex; mutant; novel; periodontopathogen; prevent; promoter; protein expression; public health relevance; response; stem; translational approach; uptake

DESCRIPTION (provided by applicant): Gram negative anaerobic bacteria are the major etiological agents of periodontal diseases. In addition, they have been shown to be associated with other health complications such as cardiovascular diseases, diabetes, and preterm low birth weight babies. Both P. gingivalis and Prev. intermedia lack the capacity to synthesize hemin and must acquire the nutrient from the environment. Despite the importance of hemin acquisition in the periodontopathogens, major gaps in knowledge exist regarding the mechanisms of uptake and regulation of the nutrient. Several loci encoding hemin transport proteins have been identified on the genome of P. gingivalis W83; however, the contribution of these loci to hemin uptake in this organism remains unknown. Also, the role of the proteins encoded by the loci is not well defined. We have identified an operon, hmuYRSTUV, required for growth of P. gingivalis with hemoglobin-haptoglobin complexes as a hemin source. A homolog of the operon is also present on the genome of other Gram-negative anaerobic bacteria including Prev. intermedia 17. Our preliminary data indicate that the hmu operon is iron regulated. Although the ferric uptake regulator, Fur, was demonstrated to regulate the expression of hemin uptake loci in variety of bacteria, our preliminary studies show the oxidative stress responsive regulator, OxyR, plays a role in regulation of expression of the hmu locus. Thus, first we will characterize the OxyR-mediated mechanism of regulation. Second, we will further define the role of the hmu locus in hemin uptake in P. gingivalis. We will start our characterization from comparison of the role of the hmu locus with the other two hemin uptake loci, iht and tlr, present on the genome of P. gingivalis W83 in hemin uptake in this organism. Next, we will test the hypothesis that the hmu operon is an important hemin acquisition mechanism and encodes proteins necessary to extract the hemin molecule from host hemoproteins and transport the hemin across both membranes (into the cytoplasm). Thus we will determine the cellular location of the hmu - encoded proteins, examine the ability of the proteins to interact with each other and with other proteins, and define the contribution of proteins encoded by the locus to hemin uptake in P. gingivalis W83. Lastly, to broaden our understanding of the role of hemin in virulence of P. gingivalis we will examine the role of hemin on gene expression in this bacterium. We predict that our studies will shed light on the role and mechanisms of hemin acquisition not only in periodontopathogens but also in other anaerobic bacteria. Such knowledge may then be used to design antimicrobial agents that will interfere with the acquisition of the essential nutrient. PUBLIC HEALTH RELEVANCE: Iron and hemin have been shown to be indispensable nutrients as well as play a role in gene regulation in P. gingivalis. However, our understanding of the hemin-iron acquisition and regulation mechanisms of this organism is rudimentary. The cellular, molecular, and animal model approaches that we propose are expected to illuminate the mechanisms of hemin and iron acquisition. This information will serve as a platform for our future determination of the mechanisms of hemin/iron uptake. My work is guided by the conviction that a cellular and molecular understanding of iron/hemin metabolism in P. gingivalis will give way to novel translational approaches for both treating and preventing adult periodontal disease.

描述（由申请人提供）：革兰氏阴性厌氧细菌是牙周疾病的主要病因。此外，它们已被证明与其他健康并发症有关，例如心血管疾病，糖尿病和早产儿。牙龈疟原虫和上述。 Intermedia缺乏合成HEMIN的能力，必须从环境中获取营养素。尽管在牙周病患者中获得HEMIN的重要性，但知识上的主要差距在养分的摄取和调节机制方面存在。在牙龈疟原虫W83的基因组上已经鉴定出了几个编码HEMIN转运蛋白的基因座。然而，这些基因座对这种生物体中摄取的贡献仍然未知。同样，由基因座编码的蛋白质的作用也没有很好地定义。我们已经确定了一个用血红蛋白 - 热蛋白复合物生长的操纵子hmuyrstuv是hm蛋白伴蛋白复合物作为半源。操纵子的同源物也存在于其他革兰氏阴性厌氧菌细菌的基因组上。 Intermedia 17。我们的初步数据表明HMU操纵子受铁调节。尽管证明了铁的摄取调节剂Fur，可以调节多种细菌中Hemin摄取基因座的表达，但我们的初步研究表明，氧化应激响应性调节剂Oxyr在调节HMU基因座的表达中起作用。因此，首先，我们将表征Oxyr介导的调节机制。其次，我们将进一步定义HMU基因座在牙龈疟原虫中的Hemin摄取中的作用。我们将从将HMU基因座的作用与其他两个Hemin摄取基因座（IHT和TLR）的作用进行比较开始，该作用存在于该生物体中Hemin摄取中的Gingivalis W83基因组上。接下来，我们将检验以下假设：HMU操纵子是一种重要的Hemin采集机制，并编码从宿主血蛋白中提取半分子并将Hemin转运到两个膜（进入细胞质）所需的蛋白质。因此，我们将确定HMU-编码蛋白的细胞位置，检查蛋白质相互相互作用和其他蛋白质相互作用的能力，并定义由基因座W83中牙龈疟原虫摄取的蛋白质的贡献。最后，为了扩大我们对Hemin在牙龈疟原虫毒力中的作用的理解，我们将研究Hemin对基因表达在该细菌中的作用。我们预测，我们的研究将不仅在牙周病患者中，而且在其他厌氧细菌中阐明了Hemin获取的作用和机制。然后，这些知识可用于设计抗菌剂，以干扰基本营养素的获取。 公共卫生相关性：铁和hemin已被证明是必不可少的营养，并且在牙龈疟原虫的基因调节中起作用。但是，我们对这种生物体的血液征收和调节机制的理解是基本的。我们提出的细胞，分子和动物模型方法有望阐明hemin和铁的获取机制。这些信息将作为我们将来确定hemin/铁吸收机制的平台。我的工作以这样的信念为指导，即在牙龈疟原虫中对铁/血素代谢的细胞和分子理解将让位于治疗和预防成人牙周疾病的新型翻译方法。