Candida albicans Adhesins Als1 and Hwp1 Modulate Interactions with Streptococcus mutans

Abstract

Candida albicans and Streptococcus mutans are known to synergistically interact with each other in the oral cavity. For example, glucosyltransferase B (GtfB), secreted by S. mutans, can bind to the C. albicans cell surface, promoting dual-species biofilm formation. However, the fungal factors mediating interactions with S. mutans are unknown. The C. albicans adhesins Als1, Als3, and Hwp1 are key players in C. albicans single-species biofilm formation, but their roles, if any, in interacting with S. mutans have not been assessed. Here, we investigated the roles of the C. albicans cell wall adhesins Als1, Als3, and Hwp1 on forming dual-species biofilms with S. mutans. We assessed the abilities of the C. albicans wild-type als1Δ/Δ, als3Δ/Δ, als1Δ/Δ/als3Δ/Δ, and hwp1Δ/Δ strains to form dual-species biofilms with S. mutans by measuring optical density, metabolic activity, cell enumeration, biomass, thickness, and architecture of the biofilms. We observed that the C. albicans wild-type strain formed enhanced dual-species biofilms in the presence of S. mutans in these different biofilm assays, confirming that C. albicans and S. mutans synergistically interact in the context of biofilms. Our results reveal that C. albicans Als1 and Hwp1 are major players in interacting with S. mutans, since dual-species biofilm formation was not enhanced when the als1Δ/Δ or hwp1Δ/Δ strains were cultured with S. mutans in dual-species biofilms. Als3, however, does not seem to play a clear role in interacting with S. mutans in dual-species biofilm formation. Overall, our data suggest that the C. albicans adhesins Als1 and Hwp1 function to modulate interactions with S. mutans and could be potential targets for future therapeutics.

Mitochondrial Protease Oct1p Regulates Mitochondrial Homeostasis and Influences Pathogenicity through Affecting Hyphal Growth and Biofilm Formation Activities in Candida albicans

“…Subsequently, we conducted a screening of annotated genes associated with C. albicans adherence, growth, and aggregation within the differentially expressed genes (DEGs) of the oct1 ∆/∆ mutant, utilizing the Kyoto Encyclopedia of Genes and Genomes (KEGG) database for enrichment analysis. The expression levels of seven genes were identified ( Figure 3 D), including genes such as ECE1 , which has been associated with the virulence factors of C. albicans , such as adhesion, biofilm formation, and filamentation properties, and ALS1 and ALS3 in the lectin-like sequence family that plays essential roles in the processes of adherence and biofilm formation in vitro, as well as the high-affinity iron permease FTR1 , a gene crucial for C. albicans growth [ 35 , 36 , 37 ]. To further confirm the transcription levels of these genes, quantitative real-time PCR was used to verify the expression levels of these four genes.…”

“…We found a significant down-regulation in the transcript levels of four regulators associated with hyphal growth and adhesion in the oct1 ∆/∆ mutant compared to the WT. These regulators consist of ECE1 , which has been linked to the adhesion, biofilm formation, and filamentation characteristics of C. albicans ; lectin-like sequence families ALS1 and ALS3 involved in in vitro biofilm formation; and FTR1 , a gene essential for the growth of C. albicans during systemic infection [ 35 , 37 , 43 ]. Based on the results of RNA-seq analysis, we further observed the effect of OCT1 deletion on hyphal formation.…”

Transcriptional analysis of oxidative and nitrosative stress on oral opportunistic Candida albicans

“…Of concern, the ALS1 and MLH1 recorded a significant upregulation when treated with those stress compounds. ALS1 is known to have a vital role in biofilm formation and host interaction [21]. This indicates that a high level of HNO3 can induce the yeast to form stronger biofilms, which may be a protective mechanism toward inhibition of the stress to enter cells of the yeast [22].…”