Project description:Our group recently transcriptomically characterized coculture growth between Streptococcus mutans and several species of commensal streptococci (Rose et al, 2023; Choi et al 2024). One interaction that stood out was with Streptococcus mitis ATCC 49456, which completely inhibited the growth of S. mutans during biofilm formation. This is due to abudant hydrogen peroxide production by S. mitis ATCC 49456, 3-5x higher than other oral commensal streptococci we have worked with. To understand how the transcriptome of S. mutans is modified in coculture with a high hydrogen peroxide producer, we evaluated the transcriptome during monoculture or coculture growth between the two strains. Our results show differential gene expression (DEGs) in S. mutans that follows other trends we have documented previously with other commensal Streptococcus species, as well as DEGs specific to the interaction with S. mitis.
Project description:Chronic obstructive pulmonary disease (COPD) is associated with airway inflammation and microbiota dysbiosis. However, the function of lung microbiome alteration in early COPD remains unclear. This study is the first to characterize the lower respiratory tract microbiota in early COPD patients via bronchoalveolar lavage fluid (BALF) samples. By using full-length 16S sequencing, we found that the lung microbiome of early COPD patients had lower bacterial richness and significant compositional differences than did that of the healthy smoker controls. Streptococcus was the most robustly distinguished genus in early COPD patients and was associated with decreased lung function and increased host local inflammation. Furthermore, a murine cigarette smoke model of early COPD revealed that Streptococcus mitis promotes the progression of early COPD. Single-cell transcriptomics revealed that Streptococcus mitis increased emphysematous destruction of the lung parenchyma in a mouse early COPD model by regulating the function of alveolar type II (AT2) cells and macrophages. Therefore, targeting the lower airway microbiota in combination with smoking cessation may be a potential therapeutic approach for early COPD.