High Biofilm Formation of Non-Smooth Candida parapsilosis Correlates with Increased Incorporation of GPI-Modified Wall Adhesins

Abstract

: Candida parapsilosis is among the most frequent causes of candidiasis. Clinical isolates of this species show large variations in colony morphotype, ranging from round and smooth to a variety of non-smooth irregular colony shapes. A non-smooth appearance is related to increased formation of pseudohyphae, higher capacity to form biofilms on abiotic surfaces, and invading agar. Here, we present a comprehensive study of the cell wall proteome of C. parapsilosis reference strain CDC317 and seven clinical isolates under planktonic and sessile conditions. This analysis resulted in the identification of 40 wall proteins, most of them homologs of known Candida albicans cell wall proteins, such as Gas, Crh, Bgl2, Cht2, Ecm33, Sap, Sod, Plb, Pir, Pga30, Pga59, and adhesin family members. Comparative analysis of exponentially growing and stationary phase planktonic cultures of CDC317 at 30 °C and 37 °C revealed only minor variations. However, comparison of smooth isolates to non-smooth isolates with high biofilm formation capacity showed an increase in abundance and diversity of putative wall adhesins from Als, Iff/Hyr, and Hwp families in the latter. This difference depended more strongly on strain phenotype than on the growth conditions, as it was observed in planktonic as well as biofilm cells. Thus, in the set of isolates analyzed, the high biofilm formation capacity of non-smooth C. parapsilosis isolates with elongated cellular phenotypes correlates with the increased surface expression of putative wall adhesins in accordance with their proposed cellular function.

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“…Compared to reference strain ATCC 2001, proteomic analysis of biofilm cells showed increased incorporation of adhesins in PEU1221, confirming the earlier noted correlation between biofilm-forming capacity and adhesin incorporation in Candida (Goḿez-Molero et al, 2015;Moreno-Martıńez et al, 2021). Not only the relative abundance of adhesin peptides was higher in strain PEU1221, also more different adhesin peptides and proteins were identified.…”

“…Previous work has shown that HBF phenotypes may coincide with increased cell surface hydrophobicity, increased cell-cell aggregation, and faster sedimentation in liquid (Goḿez-Molero et al, 2015;Moreno-Martıńez et al, 2021). This is also the case for PEU1221.…”

“…More than by changing growth conditions, notable plasticity in incorporation of wall adhesins was observed when comparing strains with differences in their capacity to form biofilm. In both species, a positive correlation was observed between the biofilm-forming capacity of isolates and the incorporation of adhesins (Gómez-Molero et al, 2015;Moreno-Martıńez et al, 2021). PEU1221 is a clinical C. glabrata strain isolated from an infected venous catheter and was shown to have an about tenfold higher capacity to form biofilm onto polystyrene than reference strain ATCC 2001.…”

“…Previous studies have revealed correlations between the capacity to form biofilms and the incorporation of cell wall adhesins in Candida (Goḿez-Molero et al, 2015;Moreno-Martıńez et al, 2021). This prompted us to investigate the incorporation of cell wall adhesins in strain PEU1221 in comparison to ATCC 2001, a low-biofilm-forming (LBF) strain, using a proteomic approach.…”

Characterization of Awp14, A Novel Cluster III Adhesin Identified in a High Biofilm-Forming Candida glabrata Isolate

“…Previous studies have revealed correlations between the capacity to form biofilms and the incorporation of cell wall adhesins in Candida ( Gómez-Molero et al., 2015 ; Moreno-Martínez et al., 2021 ). This prompted us to investigate the incorporation of cell wall adhesins in strain PEU1221 in comparison to ATCC 2001, a low-biofilm-forming (LBF) strain, using a proteomic approach.…”