Cellular Components Mediating Coadherence of Candida albicans and Fusobacterium nucleatum

Area of Science:

• Microbiology
• Oral Biology
• Pathogenesis

Background:

• Candida albicans and Fusobacterium nucleatum are opportunistic pathogens often found together in oral diseases.
• Their physical coadherence facilitates colonization and contributes to polymicrobial pathogenesis.
• Previous research suggested carbohydrate and protein interactions mediate this coadherence, but specific components remained unknown.

Purpose of the Study:

• To identify the specific genetic determinants responsible for the coaggregation between Candida albicans and Fusobacterium nucleatum.
• To elucidate the molecular mechanisms underlying the physical interaction between these two oral pathogens.

Main Methods:

• Screening of a Candida albicans SN152 mutant library.
• Screening of a panel of Fusobacterium nucleatum 23726 outer membrane protein mutants.
• In vitro coaggregation assays using wild-type strains and identified mutants, with inhibition studies using arginine and mannose.

Main Results:

• Identification of FLO9 in C. albicans (encoding a mannoprotein) and radD in F. nucleatum (encoding an adhesin) as key genes mediating interspecies coadherence.
• Demonstration that arginine and mannose significantly inhibit the coaggregation between wild-type F. nucleatum and C. albicans.
• Evidence for a complex, multifaceted mechanism underlying the physical interaction between these species.

Conclusions:

• FLO9 and radD are major genetic components involved in Candida albicans-Fusobacterium nucleatum coaggregation.
• Targeting these identified adhesins and their associated molecules could lead to novel therapeutic strategies.
• Understanding these interactions provides crucial knowledge for developing treatments against polymicrobial oral diseases.