Dual transcriptome of Streptococcus mutans and Candida albicans interplay in biofilms

ABSTRACT

Objective

To assess the interactions between Streptococcus mutans and Candida albicans during cariogenic biofilm formation.

Methods

The S. mutans and C. albicans duo-species biofilms were formed in 1% sucrose to mimic the high caries risk challenges. The biofilm structure was assessed using two-photon laser confocal microscopy. The transcriptome of 48h-biofilms was assessed by RNA-Seq. The expression of S. mutans and C. albicans virulence genes was examined via real-time reverse transcription-polymerase chain reaction.

Results

The morphogenesis of C. albicans-S. mutans duo-species biofilms was significantly altered when comparing to S. mutans or C. albicans single-species biofilm. Duo-species biofilms exhibited unique expression profile with a large number of differentially expressed genes (DEGs), including a higher expression of S. mutans atpD (acid-adaptive), C. albicans CHT2 (fungal cell wall chitin remodeling), and C. albicans SOD3 (cytotoxic oxygen radical destroying) (p < 0.05). KEGG pathway analyses further revealed that the majority of the up-regulated DEGs are related to microbial metabolism. Furthermore, the expressions of S. mutans and C. albicans key virulence genes (gtfB, gtfC, gtfD, ECE1, HWP1, ERG4, CHT2) were associated with sugar availability-related and time-related dynamics.

Conclusion

Cross-kingdom interactions impact S. mutans-C. albicans biofilm formations and dynamic expressions of virulence genes.

KEYWORDS:

• Biofilms
• dental caries
• transcriptome
• streptococcus mutans
• candida albicans
• oral infection

Acknowledgments

Dr. Xiao’s research was supported by NIDCR (K23DE027412 and R01DE031025). The funding agencies had no role in the study design, data collection, analyses, decision to publish, or preparation of the manuscript.

Author contributions

YZ and JX contributed to the conception, design, data acquisition, analysis, and interpretation, drafting and critically revising the manuscript; ER and TTW contributed to data acquisition, analysis, and interpretation, drafting and critically revising the manuscript; XH contributed to data acquisition and data interpretation; MF was involved in critical revision of the manuscript. All authors have read and approved the final version of the manuscript and agree to be accountable for all aspects of the work.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/20002297.2022.2144047

Additional information

Funding

This work was supported by the National Institute of Dental and Craniofacial