Oral Sciences, Faculty of Dentistry, National University of Singapore, Singapore.
Center of Oral and Craniofacial Biology, School of Dentistry, Louisiana State University Health Sciences Center, New Orleans, Louisiana, USA.
Infect Immun. 2019 Sep 19;87(10). doi: 10.1128/IAI.00339-19. Print 2019 Oct.
, a major opportunistic fungal pathogen, is frequently found together with in dental biofilms associated with severe childhood caries (tooth decay), a prevalent pediatric oral disease. However, the impact of this cross-kingdom relationship on remains largely uncharacterized. Here, we employed a novel quantitative proteomics approach in conjunction with transcriptomic profiling to unravel molecular pathways of when cocultured with in mixed biofilms. RNA sequencing and iTRAQ (isobaric tags for relative and absolute quantitation)-based quantitative proteomics revealed that genes and proteins associated with carbohydrate metabolism were significantly enhanced, including sugar transport, aerobic respiration, pyruvate breakdown, and the glyoxylate cycle. Other genes and proteins directly and indirectly related to cell morphogenesis and cell wall components such as mannan and glucan were also upregulated, indicating enhanced fungal activity in mixed-species biofilm. Further analyses revealed that -derived exoenzyme glucosyltransferase B (GtfB), which binds to the fungal cell surface to promote coadhesion, can break down sucrose into glucose and fructose that can be readily metabolized by , enhancing growth and acid production. Altogether, we identified key pathways used by in the mixed biofilm, indicating an active fungal role in the sugar metabolism and environmental acidification (key virulence traits associated with caries onset) when interacting with , and a new cross-feeding mechanism mediated by GtfB that enhances carbohydrate utilization. In addition, we demonstrate that comprehensive transcriptomics and quantitative proteomics can be powerful tools to study microbial contributions which remain underexplored in cross-kingdom biofilms.
作为一种主要的机会性真菌病原体，常与 在与严重儿童龋齿（蛀牙）相关的牙菌斑中共同发现，这是一种普遍的儿科口腔疾病。然而，这种跨界关系对 的影响在很大程度上仍未被描述。在这里，我们采用了一种新的定量蛋白质组学方法结合转录组分析，以揭示 与 共培养时混合生物膜中 的分子途径。RNA 测序和 iTRAQ（相对和绝对定量的同重同位素标记）基于定量蛋白质组学显示，与碳水化合物代谢相关的 基因和蛋白质显着增强，包括糖转运、需氧呼吸、丙酮酸分解和乙醛酸循环。其他与细胞形态发生和细胞壁成分直接和间接相关的 基因和蛋白质，如甘露聚糖和葡聚糖，也被上调，表明混合物种生物膜中真菌活性增强。进一步分析表明，来自 的外切酶葡糖基转移酶 B (GtfB) 结合到真菌细胞表面以促进共黏附，可以将蔗糖分解成葡萄糖和果糖， 可以很容易地代谢，增强生长和产酸。总的来说，我们确定了 在混合生物膜中使用的关键途径，表明 在与 相互作用时，在糖代谢和环境酸化（与龋齿发病相关的关键毒力特征）中发挥积极的真菌作用，以及由 GtfB 介导的新的交叉喂养机制增强了 的碳水化合物利用。此外，我们证明了综合转录组学和定量蛋白质组学可以成为研究微生物贡献的有力工具，这些贡献在跨界生物膜中仍未得到充分探索。
