Oral alkali production and caries prevention in children

摘要 这是对马塞勒·纳西门托博士的K23奖的修订申请，马塞勒·纳西门托博士是麻省理工学院的助理教授 佛罗里达大学牙医学院(UFCD)。纳西门托博士一直在进行临床翻译 重点研究口腔定植细菌的产碱能力及其在口腔中的作用 口腔健康和龋齿。纳西门托博士的目标是成为一名领先的独立研究人员 和追求创造基于口腔碱生产的新的治疗靶点， 可能会从根本上改变我们评估龋齿风险和预防龋齿的方式。她已经组装了一个 由罗伯特·伯恩博士(UFCD)、罗伯特·普里莫什博士(UFCD)和弗洛伊德博士组成的杰出导师小组 DeWhirst(Forsyth Institute)和顾问Jorge Frias-Lopez博士(Forsyth Institute)确保成功 她的职业发展和拟议的研究性学习。这个K23奖将极大地促进她的事业 通过提供以下方面的结构和指导进行开发：(1)设计和开发方面的专业知识 开展以病人为中心的研究；(2)生物信息学和微生物组数据分析培训；(3) 在申请和管理联邦资金方面的经验和指导，以及(4)时间释放和 用于生成数据和出版物的资源，以便在授权期结束前支持RO1申请。 口腔细菌产碱对牙菌斑的生化和代谢有重要影响 降低口腔生物膜致龋性的方式。尽管斑块细菌产酸已知 作为龋齿的直接原因，值得注意的是，耐酸微生物比例的增加似乎 发生的代价是酸度较低且通常与口腔健康有关的物种-许多 它们被认为是产碱细菌。生物膜中产碱菌的流失 人群可能会降低斑块中和酸的能力，并减缓斑块pH恢复到更高的 中性值。纳西门托博士的研究小组的临床研究提供了重要的支持，而 口腔细菌产碱可能是成年人患龋齿风险的关键决定因素。具体地说， 无龋齿受试者菌斑和唾液中的细菌群具有更大的产生能力 来自精氨酸的氨，精氨酸是口腔中主要的产碱底物之一，当 与龋齿活跃的受试者的细菌种群相比。微生物组成和组成的差异 产碱系统的调节可能是影响口腔样本容量的关键因素 不同的受试者代谢精氨酸。在已知的口腔细菌产碱系统中，精氨酸 脱亚胺酶系统(ADS)可能是斑块中最重要的pH稳态机制，并且 似乎在主要方面有助于抵抗龋齿。通过精氨酸脱羧酶 (ADC)，精氨酸也可以被胍丁胺脱亚胺酶分解为甘露糖，然后再分解为氨。 系统(AGDS)。虽然最近她对口服精氨酸分解活性有了新的和重要的发现 口腔细菌精氨酸分解代谢潜力的成人临床研究和儿童初步研究 来自不同龋齿状态的儿童仍未被探索，尽管这一途径对于 菌斑pH动态平衡与龋齿。同样，关于口腔细菌的基本问题仍然存在： (A)体质的精氨酸分解能力，(B)对ADS和AGDS的管制的敏感性，(C)体质酸 (D)基因含量，因为它与ADS和AGDS在口腔生物膜生态中的作用有关， 健康和疾病。因此，拟议试验的目标是：(1)继续调查 精氨酸和胍丁胺产生的口腔碱与儿童龋病的关系 以及(Ii)深入了解牙龈上的微生物学、生态学和超基因组学 产氨细菌群落及其与口腔健康和龋齿的关系。这些 研究将为制定新的龋病风险策略提供必要的基线信息。 基于碱改性口腔生物膜pH和生态的评价与防龋 制作。

ABSTRACT This is a revised application for the K23 award for Dr. Marcelle Nascimento, an Assistant Professor at the University of Florida, College of Dentistry (UFCD). Dr. Nascimento has been conducting clinical-translational research projects focusing on the alkali-producing capacity of bacteria colonizing the oral cavity and its role in oral health and dental caries. Dr. Nascimento aims to become a leading and independent researcher in the field of Cariology and to pursue the creation of novel therapeutic targets based on oral alkali production that may fundamentally change the way in which we assess caries risk and prevent caries. She has assembled an outstanding mentoring group comprised by Drs. Robert Burne (UFCD), Robert Primosch (UFCD) and Floyd Dewhirst (Forsyth Institute) and the consultant Dr. Jorge Frias-Lopez (Forsyth Institute) to insure the success of her career development and proposed research study. This K23 award will greatly facilitate her career development by providing the structure and the guidance for acquiring: (1) expertise on designing and conducting patient-oriented studies, (2) training on bioinformatics and microbiome data analysis, (3) experience and mentoring in requesting and managing federal funds, and (4) the time release and the resources to generate data and publications to support an RO1 application by the end of the award period. Alkali production by oral bacteria has a major impact on dental plaque biochemistry and metabolism in a manner that reduces the cariogenicity of oral biofilms. Although acid production by plaque bacteria is known as the direct cause of caries, it is noteworthy that increases in the proportions of aciduric organisms appear to occur at the expense of species that are less aciduric and commonly associated with oral health - many of which have been recognized as alkali-producing bacteria. Loss of alkali-producing bacteria from the biofilm populations may reduce the capacity of plaque to neutralize acids and slow the return of plaque pH to more neutral values. Clinical studies from Dr. Nascimento's research group offer significant support that a lack of alkali production by oral bacteria may be a critical determinant of caries risk in adults. Specifically, the bacterial populations from plaque and saliva of caries-free subjects have a greater capacity to produce ammonia from arginine, which is one of the predominant alkali-yielding substrates in the oral cavity, when compared to bacterial populations from caries-active subjects. Differences in the microbial composition and regulation of the alkali-producing systems may be critical factors affecting the capacity of oral samples from different subjects to metabolize arginine. Of the known alkali-generating systems by oral bacteria, the arginine deiminase system (ADS) is perhaps the single most significant pH homeostasis mechanism in plaque, and appears to contribute in major ways to resistance to caries. Through the arginine decarboxylase enzyme (ADC), arginine can also be catabolized into agmantine and then into ammonia by the agmatine deiminase system (AgDS). While novel and important findings on oral arginolytic activity have recently arisen from her clinical study with adults and preliminary study with children, the arginine catabolic potential of oral bacteria from children with different caries-status remains unexplored, in spite of the importance of this pathway to plaque pH homeostasis and caries. Likewise, fundamental questions remain with regards to the oral bacteria: (a) constitutional arginolytic capacity, (b) sensitivity to regulation of the ADS and AgDS, (c) constitutional acid resistance, and (d) gene content, as it correlates to the role of ADS and AgDS in the ecology of oral biofilms, health and disease. Accordingly, the goals of the proposed experimentation are: (i) to continue to investigate the relationship between oral alkali production from arginine and agmatine and caries experience in children, and (ii) to gain insights into the fundamental microbiology, ecology and metagenomics of supragingival ammonia-producing bacterial communities and their relationship to oral health and dental caries. These studies will provide essential baseline information for the development of new strategies for caries risk assessment and caries control that are based on modification of oral biofilm pH and ecology through alkali production.