Role of Dispersin B in the colonization and virulence of Aggregatibacter actinomycetemcomitans

分散素 B 在放线菌聚集菌定植和毒力中的作用

• 批准号: 9525196
• 负责人: NARAYANAN RAMASUBBU
• 金额: $ 23.85万
• 依托单位: RBHS-SCHOOL OF DENTAL MEDICINE
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9525196
• 关键词: Actinobacillus actinomycetemcomitans; Adolescent; Adult; Affect; African American; Alveolar Bone Loss; Animals; Bacteria; Bacterial Infections; Carbon; Cells; Clinical; Coculture Techniques; Control Groups; Diagnosis; Disease; Distal; Ecosystem; Elderly; Ensure; Environment; Enzymes; Epidemic; Etiology; Exhibits; Famines; Food; Gene Expression Regulation; Genes; Genetic Transcription; Glucosamine; Goals; Growth; Habitats; Habits; Human; Hydrolysis; Immobilization; Immune response; In Vitro; Individual; Laboratories; Life Style; Link; Location; Metabolic; Methods; Microbial Biofilms; Minority; Modeling; Mouth Diseases; Movement; Nutrient; Nutritional; Oral cavity; Periodontitis; Play; Polymers; Polysaccharides; Population; Positioning Attribute; Rattus; Reporting; Role; Seeds; Serotyping; Site; Source; Starvation; Streptococcus gordonii; Surface; Surgeon; Surveys; Testing; Tissue-Specific Gene Expression; Up-Regulation; Virulence; adolescent patient; bone loss; commensal bacteria; depolymerization; experimental study; extracellular; feeding; microorganism; mutant; nutrition; operation; overpopulation; transcriptome sequencing; virtual

Abs tract Aggregatibacter actinomycetemcomitans (Aa) and other bacteria attach to biotic and abiotic surfaces and produce exopolysaccharides, which are used to immobilize the bacterial cells on these colonized surfaces forming a biofilm matrix. The exopolysaccharide produced by Aa is a homopolymer of N-acetyl-D- glucosamine (GlcNAc) with b-1,6-linked units (abbreviated as PGA). During biofilm growth, to overcome starvation associated with overpopulation, cells must disperse from a surface to move to distal surfaces to colonize further. This movement of released cells of Aa is facilitated by the hydrolytic action of Dispersin B (DspB), an enzyme produced by Aa, which releases cells that are enmeshed in the biofilm matrix. The product of PGA hydrolysis, GlcNAc, is present around the mature biofilm and could become a nutrient for Aa and other neighboring bacteria. In a multispecies biofilm where many bacteria co-habitat, Aa gains nutrients by positioning itself near the commensal bacterium, Streptococcus gordonii (Sg). In this scenario, Aa can utilize the lactate produced by Sg, a preferred carbon source, for its growth. In order to maintain the presence of Sg in its vicinity, in reciprocation, Aa supplies the neighboring Sg with GlcNAc through the action of DspB on PGA. Since GlcNAc is a preferred carbon source for Sg, both bacteria can survive by entering into a nutritional co-operation wherein both have an advantage for persistent colonization in the niche. It should be noted that mutualistic or cooperative cross-feeding between bacteria is favored in biofilms (2). Our hypothesis is that 1) PGA-derived GlcNAc, not exogenous GlcNAc, is important for the survival and colonization of Aa in the biofilm and metabolic cross-feeding relationship with Sg; 2) DspB is required for the virulence of Aa. We will test these hypotheses with the following Specific Aims: Specific Aim 1: a) Demonstrate that DspB is essential for the survival of Aa in a biofilm mode of growth. b) Demonstrate that DspB is essential to maintain the cross-feeding relationship and cooperative nutrient exchange with Sg. Specific Aim 2: Characterize the role of DspB in the colonization and virulence of Aa in the oral cavity.

腹肌束 伴放线聚集杆菌（Aa）和其他细菌附着于生物和非生物表面， 产生胞外多糖，用于将细菌细胞粘附在这些殖民表面上 形成生物膜基质。由Aa产生的胞外多糖是N-乙酰基-D-乙酰基-N 具有B-1，6-连接单元的葡糖胺（GlcNAc）（缩写为PGA）。在生物膜生长期间，为了克服 饥饿与过度繁殖有关，细胞必须从表面分散到远端表面， 进一步殖民。分散素B的水解作用促进了Aa释放细胞的这种移动 （DspB），由Aa产生的酶，其释放陷入生物膜基质中的细胞。产品 PGA水解的GlcNAc存在于成熟的生物膜周围，可以成为Aa的营养物， 邻近的细菌。在许多细菌共同栖息的多物种生物膜中，Aa通过以下方式获得营养 将其自身定位在嗜酸细菌戈登链球菌（Streptococcus gordonii，Sg）附近。在这种情况下，Aa可以利用 由Sg产生的乳酸盐，优选的碳源，用于其生长。为了保持Sg的存在 在其附近，在往复运动中，Aa通过DspB的作用向相邻的Sg提供GlcNAc， PGA。由于GlcNAc是Sg的优选碳源，因此两种细菌都可以通过进入营养环境而存活。 合作，其中两者都具有在小生境中持续定殖的优势。应注意 在生物膜中，细菌之间的互惠或合作交叉喂养是有利的（2）。我们的假设是：（1） PGA衍生的GlcNAc，而不是外源性GlcNAc，对于Aa在细胞中的存活和定殖是重要的。 生物被膜和代谢与Sg的交叉摄食关系; 2）DspB是Aa毒力所必需的。我们将 通过以下具体目标来检验这些假设： 具体目标1：a）证明DspB对于Aa在生物膜生长模式中的存活是必需的。 B）证明Dsp B对维持交叉喂养关系至关重要， 与Sg. 具体目标2：表征DspB在口腔中Aa定殖和毒力中的作用。