The primer sequences for real-time PCR.

The ecological interplay between Streptococcus mutans and Candida albicans within dental plaque biofilms is an important factor driving pathogenesis of dental caries. This study aimed to investigate S. mutans regulation of C. albicans growth and virulence through extracellular membrane vesicles (EMVs) and modulation of ubiquitination, a key protein post-translational modification. We established a transwell co-culture model to enable “contact-independent” interactions between S. mutans and C. albicans. S. mutans EMVs were found to directly associate with C. albicans cells and promote biofilm formation and growth. Quantitative ubiquitination profiling revealed S. mutans dramatically alters the ubiquitination landscape in C. albicans. We identified 10,661 ubiquitination sites across the C. albicans proteome and their enrichment in pathways related to translation, metabolism, and stress adaptation. Co-culture with S. mutans led to upregulation of ubiquitination on 398 proteins involved in sugar catabolism and generation of reducing power. S. mutans upregulated ubiquitination of superoxide dismutase-3 of C. albicans, inducing its degradation and heightened reactive oxygen species levels, and concomitantly stimulated C. albicans growth. Our findings elucidate EMVs and ubiquitination modulation as key mechanisms governing the S. mutans-C. albicans interplay and provide new insights into the promotion of a cariogenic oral biofilm environment. This study significantly advances understanding of the complex molecular interactions underlying dental plaque dysbiosis and caries pathogenesis.

变形链球菌（Streptococcus mutans）与白色念珠菌（Candida albicans）在牙菌斑生物膜内的生态相互作用，是驱动龋病发病的关键致病因素。本研究旨在探究变形链球菌通过细胞外膜囊泡（extracellular membrane vesicles，EMVs）以及泛素化（ubiquitination，一种核心蛋白质翻译后修饰），对白色念珠菌生长与毒力的调控机制。我们构建了Transwell共培养模型以实现两种菌间的非接触性互作，研究发现变形链球菌来源的EMVs可直接结合白色念珠菌细胞，并促进其生物膜形成与生长。定量泛素化谱分析显示，变形链球菌可显著重塑白色念珠菌的泛素化景观。本研究在白色念珠菌蛋白质组中共鉴定到10661个泛素化位点，这些位点显著富集于翻译、代谢及应激适应相关通路。与变形链球菌共培养可使398个参与糖代谢与还原当量生成的蛋白质的泛素化水平上调。此外，变形链球菌可上调白色念珠菌超氧化物歧化酶3的泛素化水平，诱导其降解并提升细胞内活性氧水平，同时促进白色念珠菌生长。本研究阐明了EMVs与泛素化调控作为介导变形链球菌-白色念珠菌互作的核心机制，为揭示致龋性口腔生物膜微环境的形成提供了全新视角。本研究显著推进了学界对牙菌斑菌群失调及龋病发病背后复杂分子互作机制的认知。