A Multifaceted Study of Scedosporium boydii Cell Wall Changes during Germination and Identification of GPI-Anchored Proteins

PLoS One. 2015 Jun 3;10(6):e0128680. doi: 10.1371/journal.pone.0128680. eCollection 2015.

Abstract

Scedosporium boydii is a pathogenic filamentous fungus that causes a wide range of human infections, notably respiratory infections in patients with cystic fibrosis. The development of new therapeutic strategies targeting S. boydii necessitates a better understanding of the physiology of this fungus and the identification of new molecular targets. In this work, we studied the conidium-to-germ tube transition using a variety of techniques including scanning and transmission electron microscopy, atomic force microscopy, two-phase partitioning, microelectrophoresis and cationized ferritin labeling, chemical force spectroscopy, lectin labeling, and nanoLC-MS/MS for cell wall GPI-anchored protein analysis. We demonstrated that the cell wall undergoes structural changes with germination accompanied with a lower hydrophobicity, electrostatic charge and binding capacity to cationized ferritin. Changes during germination also included a higher accessibility of some cell wall polysaccharides to lectins and less CH3/CH3 interactions (hydrophobic adhesion forces mainly due to glycoproteins). We also extracted and identified 20 GPI-anchored proteins from the cell wall of S. boydii, among which one was detected only in the conidial wall extract and 12 only in the mycelial wall extract. The identified sequences belonged to protein families involved in virulence in other fungi like Gelp/Gasp, Crhp, Bglp/Bgtp families and a superoxide dismutase. These results highlighted the cell wall remodeling during germination in S. boydii with the identification of a substantial number of cell wall GPI-anchored conidial or hyphal specific proteins, which provides a basis to investigate the role of these molecules in the host-pathogen interaction and fungal virulence.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Cell Wall / chemistry*
  • Cell Wall / metabolism
  • Cell Wall / ultrastructure
  • Ferritins / genetics
  • Ferritins / metabolism
  • Fungal Polysaccharides / chemistry
  • Fungal Polysaccharides / metabolism
  • Fungal Proteins / genetics*
  • Fungal Proteins / metabolism
  • GPI-Linked Proteins / genetics*
  • GPI-Linked Proteins / isolation & purification
  • GPI-Linked Proteins / metabolism
  • Gene Expression Regulation, Fungal*
  • Glycosylphosphatidylinositols / chemistry
  • Glycosylphosphatidylinositols / metabolism
  • Hydrophobic and Hydrophilic Interactions
  • Lectins / chemistry
  • Lectins / metabolism
  • Molecular Sequence Annotation
  • Molecular Sequence Data
  • Mycelium / genetics
  • Mycelium / growth & development
  • Mycelium / metabolism
  • Mycelium / ultrastructure
  • Protein Binding
  • Scedosporium / genetics*
  • Scedosporium / growth & development
  • Scedosporium / metabolism
  • Scedosporium / ultrastructure
  • Spores, Fungal / genetics*
  • Spores, Fungal / growth & development
  • Spores, Fungal / metabolism
  • Spores, Fungal / ultrastructure
  • Static Electricity
  • Superoxide Dismutase / genetics
  • Superoxide Dismutase / metabolism

Substances

  • Fungal Polysaccharides
  • Fungal Proteins
  • GPI-Linked Proteins
  • Glycosylphosphatidylinositols
  • Lectins
  • Ferritins
  • Superoxide Dismutase

Grants and funding

This work was supported by Région Pays de la Loire as part of the Myco-AFM research program. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.