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In Silico Analysis and Expression Profiling of Adhesin-Like Flocculins in Trichosporon asahii
Mateus Jorge Mendes Dos Santos1, Danielle de Castro Quinto2, Guilherme de Souza Gagliano1
1Graduate Program in Fungal Biology, Federal University of Pernambuco, Recife, Brazil.
Background:
Trichosporon asahii is an opportunistic basidiomycetous yeast increasingly recognized as a cause of invasive infections in immunocompromised individuals, often associated with high morbidity and mortality. Its ability to adhere to host tissues and abiotic surfaces is considered a critical virulence factor, yet the molecular mechanisms underlying this adhesion remain poorly understood.
Objective:
To characterize gene sequences in T. asahii belonging to the flocculin family with potential adhesive functions.
Methods:
The homologous flocculin genes DHA1, DHA2, CPL1, and CFL1, previously described in Cryptococcus neoformans as being involved in cell adhesion, were identified within the T. asahii predicted proteome. Four T. asahii strains were analyzed: two reference strains (CBS2479 and CBS7631) and two clinical strains (L2585 and L773). Cells were grown in planktonic morphology and biofilms in RPMI + MOPS medium with 2% glucose. The predominant morphology of the cells was observed using bright-field optical microscopy, and total RNA was extracted. The relative expression of the four flocculin genes was analyzed by qRT-PCR and normalized using the 2-ΔΔCt method and the actin gene.
Results:
The flocculin proteins showed high similarity and common domains with C. neoformans flocculins and other adhesins. The strains exhibited a variety of morphologies, with the T. asahii CBS2479 strain predominantly displaying yeast forms, while the T. asahii L2585 strain presented a higher quantity of hyphae. All flocculins bound to human proteins in the PriaA/Cpl1_fungi domain and/or to the Cpl1-like domain. T. asahii flocculins were downregulated when compared to the reference strain CBS2479, while the clinical strain L2585 exhibited the highest expression of the flocculin CFL1. During biofilm formation, DHA1 and CFL1 were highly expressed.
Conclusion:
Flocculins were expressed according to specific yeast/hyphal morphology and were also more expressed in biofilms, indicating their association with biofilm maintenance and development.
Insights
Trichosporon asahii flocculins are key to fungal adhesion and biofilm formation. Their expression varies with cell morphology and is upregulated in biofilms, highlighting their role in invasive infections.
Area of Science:
- Medical Mycology
- Molecular Biology
- Infectious Diseases
Background:
- Trichosporon asahii is an opportunistic yeast causing invasive infections in immunocompromised individuals.
- Cell adhesion is a critical virulence factor for T. asahii, but its molecular basis is poorly understood.
Purpose of the Study:
- To characterize flocculin family gene sequences in T. asahii.
- To investigate the potential adhesive functions of these genes.
Main Methods:
- Identified homologous flocculin genes (DHA1, DHA2, CPL1, CFL1) in T. asahii.
- Analyzed four T. asahii strains (two reference, two clinical) in planktonic and biofilm states.
- Quantified gene expression using qRT-PCR.
Main Results:
- T. asahii flocculins share similarities with Cryptococcus neoformans flocculins and bind human proteins.
- Flocculin expression varied with yeast/hyphal morphology and was highest in the clinical strain L2585 (CFL1).
- DHA1 and CFL1 were highly expressed during biofilm formation.
Conclusions:
- Flocculins are expressed based on specific yeast/hyphal morphology.
- Increased flocculin expression in biofilms suggests their involvement in biofilm maintenance and development.
- These findings contribute to understanding T. asahii virulence mechanisms.
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