Investigating Membrane Alterations as a Mechanism of Acid Tolerance in Cariogenic Bacteria

研究膜改变作为致龋细菌耐酸机制

• 批准号: 10915839
• 负责人: Jonathon Baker
• 金额: $ 24.9万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-06-01 至 2026-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10915839
• 关键词: Investigating; Membrane; Alterations; Mechanism; Acid

Dental caries is the most common chronic infectious disease globally and is caused by the formation of acid-producing bacterial biofilms on the tooth surface, which demineralize and destroy the protective underlying enamel barrier. Although the efficacy of fluoride treatments (the contemporary standard in caries prevention) is well-documented, the current prevalence of the disease clearly illustrates that fluoride alone is insufficient to prevent caries in many situations. Therefore, increased understanding of disease pathogenesis and exploration of novel preventative strategies are objectives worthy of attention. Regardless of the microbial taxa involved, bacterial acid-tolerance is an indispensable factor in caries pathogenesis. The known caries pathogen Streptococcus mutans increases the proportion of unsaturated fatty acids (UFAs) in its plasma membrane in response to environmental acidification—an adaptation required for acid-tolerance and virulence. Preliminary data indicates that several other Gram-positive oral taxa, including the caries-associated species, Lactobacillus casei, modify their membranes in a similar manner in response to environmental acidification. This proposal addresses a number of currently unanswered questions raised by these observations. Aims 1 and 2 of the proposed research will determine the scope of this response to acid stress across the oral microbiome, in single taxa or in a community setting. Aim 3 of this proposal will elucidate how these UFAs are protective against acid-mediated damage. These aims will be accomplished using bioinformatics tools, basic molecular microbiology, an ecologically-relevant and complex in vitro oral biofilm model, and mass spectrometry/lipidomics. Successful completion of the proposed research will answer pertinent questions regarding caries pathogenesis in a multispecies setting and is likely to open the door to investigation of novel anti-caries therapeutics which, while targeting acidophiles, function regardless of the presence and abundance of S. mutans. The candidate, Dr. Jonathon Baker, has a longstanding interest in the microbiology of dental caries. Upon completion of the K99 (mentored) phase of this award, his goal is to become an independent PI at a leading research university, where he plans to continue research on the modifications that bacteria make to their membranes to combat environmental stresses, while leveraging acquired data to develop novel therapeutics. A funded K99/R00 proposal will allow Dr. Baker to develop skills necessary to both complete the proposed research (training in mass spectrometry/lipidomics) and subsequently become an independent research scientist (training in didactic lecturing, mentoring, and grantsmanship). Dr. Baker’s mentors and environment: Drs. Karen Nelson (J. Craig Venter Institute), Anna Edlund (J. Craig Venter Institute/UC San Diego), Pieter Dorrestein (UC San Diego), Victor Nizet (UC San Diego) and Robert Quivey, Jr. (University of Rochester School of Medicine and Dentistry) have been carefully selected to provide high-quality, diverse scientific and collegial support, as well as state-of-the-art facilities, to ensure successful completion of this research program and the proposed career development goals.

龋齿是全球最常见的慢性感染性疾病，由牙齿表面形成的产酸细菌生物膜引起，其使保护性的底层釉质屏障脱矿并破坏。虽然氟化物治疗（当代龋齿预防标准）的有效性已得到充分证明，但目前该病的流行率清楚地表明，在许多情况下，单独使用氟化物不足以预防龋齿。因此，增加对疾病发病机制的了解和探索新的预防策略是值得关注的目标。无论涉及的微生物类群，细菌的耐酸性是一个不可或缺的因素，在龋病的发病机制。已知的龋齿病原体变形链球菌增加不饱和脂肪酸（UFA）在其质膜的比例，以响应环境酸化-所需的耐酸性和毒力的适应。初步数据表明，其他几个革兰氏阳性口腔分类群，包括龋齿相关的物种，干酪乳杆菌，修改他们的膜以类似的方式响应环境酸化。这一建议解决了这些意见所提出的一些目前尚未回答的问题。拟议研究的目标1和2将确定整个口腔微生物组对酸应激的这种反应的范围， 分类群或社区环境中。本提案的目标3将阐明这些UFA如何保护免受酸介导的损伤。这些目标将使用生物信息学工具，基础分子微生物学，生态相关的和复杂的体外口腔生物膜模型，和质谱/脂质组学来实现。成功完成拟议的研究将回答有关龋齿发病机制在多物种环境中的相关问题，并有可能打开大门，调查新的抗龋齿治疗，而目标嗜酸菌，功能无论是否存在和丰富的S。变异体候选人，乔纳森·贝克博士，对龋齿的微生物学有着长期的兴趣。在完成K99（指导）阶段后，他的目标是成为一所领先的研究型大学的独立PI，在那里他计划继续研究细菌对其膜的修饰以对抗环境压力，同时利用获得的数据开发新的疗法。一项资助的K99/R 00提案将使Baker博士能够发展完成拟议研究所需的技能（质谱/脂质组学培训），并随后成为一名独立的研究科学家（教学讲座，指导和培训）。贝克博士的导师和环境：卡伦纳尔逊博士（J.克雷格文特尔研究所），安娜Edlund（J.克雷格文特尔研究所/加州大学圣地亚哥分校），彼得Dorrestein（加州大学圣地亚哥分校），维克托Nizet（加州大学圣地亚哥分校）和罗伯特Quivey，Jr.（医学和牙科的罗切斯特学校的大学）已经精心挑选，以提供高质量，多样化的科学和合议支持，以及国家的最先进的设施，以确保成功完成这项研究计划和拟议的职业发展目标。