Characterization of Aspergillus nidulans Biofilm Formation and Structure and Their Inhibition by Pea Defensin Psd2.

Caroline Corrêa-Almeida,Rodrigo Rollin-Pinheiro,Eliana Barreto-Bergter,Luana P Borba-Santos,Sonia Rozental,Eleonora Kurtenbach

doi:10.3389/fmolb.2022.795255

Caroline Corrêa-Almeida, Rodrigo Rollin-Pinheiro + Show 4 more

Open Access

https://doi.org/10.3389/fmolb.2022.795255

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Abstract

Approximately four million people contract fungal infections every year in Brazil, primarily caused by Aspergillus spp. The ability of these fungi to form biofilms in tissues and medical devices complicates treatment and contributes to high rates of morbidity and mortality in immunocompromised patients. Psd2 is a pea defensin of 5.4 kDa that possesses good antifungal activity against planktonic cells of representative pathogenic fungi. Its function depends on interactions with membrane and cell wall lipid components such as glucosylceramide and ergosterol. In the present study, we characterized Aspergillus nidulans biofilm formation and determined the effect of Psd2 on A. nidulans biofilms. After 4 hours, A. nidulans conidia adhered to polystyrene surfaces and formed a robust extracellular matrix-producing biofilm at 24 h, increasing thickness until 48 h Psd2 inhibited A. nidulans biofilm formation in a dose-dependent manner. Most notably, at 10 μM Psd2 inhibited 50% of biofilm viability and biomass and 40% of extracellular matrix production. Psd2 significantly decreased the colonized surface area by the biofilm and changed its level of organization, causing a shortening of length and diameter of hyphae and inhibition of conidiophore formation. This activity against A. nidulans biofilm suggests a potential use of Psd2 as a prototype to design new antifungal agents to prevent biofilm formation by A. nidulans and related species.

Highlights

Plant defensins are an extensive family of cationic and cysteine-rich peptides of 45–54 amino acid residues that participate in the defense mechanism of various organisms against a wide range of microorganisms (Lay and Anderson, 2005; Vriens et al, 2014; Cools et al, 2017)
A. nidulans conidia incubated in RPMI medium did not adhere to the polystyrene surface and did not germinate (Figure 1A), whereas a robust biofilm was observed in RPMI UU and YUU media (Figures 1B,C)
The first was whether A. nidulans was able to adhere, grow, and develop an extracellular matrix (ECM)-producer biofilm, which is one of the most important virulence factors of C. albicans and A. fumigatus (González-Ramírez et al, 2016; Khan et al, 2020; Mohammadi et al, 2020)

Summary

Introduction

Plant defensins are an extensive family of cationic and cysteine-rich peptides of 45–54 amino acid residues that participate in the defense mechanism of various organisms against a wide range of microorganisms (Lay and Anderson, 2005; Vriens et al, 2014; Cools et al, 2017). Other activities, such as anti-tumoral, have been described (Hoskin and Ramamoorthy, 2008; Deslouches and Di, 2017; Do Amaral et al, 2020; Tornesello et al, 2020). The defensin is internalized and transported to the nucleus, where it interacts with cyclin F, a protein involved in controlling the cell cycle (Lobo et al, 2007; De Medeiros et al, 2014; Fernandes et al, 2016)

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