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Hog1-mediated stress tolerance in the pathogenic fungus Trichosporon asahii

Yasuhiko Matsumoto1, Yu Sugiyama2, Tae Nagamachi2

  • 1Department of Microbiology, Meiji Pharmaceutical University, 2-522-1, Noshio, Kiyose, Tokyo, 204-8588, Japan. ymatsumoto@my-pharm.ac.jp.

Scientific Reports
|August 19, 2023
PubMed

Insights

The Hog1 protein is crucial for the survival of Trichosporon asahii, a fungus causing infections in immunocompromised individuals. Its absence increases susceptibility to various stresses and reduces fungal virulence.

Area of Science:

  • Mycology
  • Molecular Biology
  • Infectious Diseases

Background:

  • Trichosporon asahii is an opportunistic pathogen causing severe infections in immunocompromised patients.
  • The mitogen-activated protein kinase Hog1 is known to regulate stress resistance in other pathogenic fungi, but its role in T. asahii remains uncharacterized.

Purpose of the Study:

  • To investigate the function of the Hog1 protein in Trichosporon asahii.
  • To determine the role of Hog1 in T. asahii's response to environmental stresses and its virulence.

Main Methods:

  • Gene deletion of hog1 in T. asahii to create a mutant.
  • Phenotypic analysis of the hog1-deficient mutant under various stress conditions (high temperature, oxidative, osmotic, drug sensitivity).
  • Assessment of fungal virulence using a silkworm infection model.

Main Results:

  • The hog1 gene-deficient T. asahii mutant showed increased sensitivity to high temperature (40°C), cell membrane stress (SDS), oxidative stress (H2O2, menadione), genotoxic stress (MMS, UV), and antifungal drugs (amphotericin B).
  • The mutant exhibited osmotic sensitivity (NaCl, KCl) under glucose-restricted conditions.
  • Virulence in silkworms was significantly attenuated, with reduced viability in hemolymph, and these defects were complemented by reintroducing the hog1 gene.

Conclusions:

  • Hog1 is essential for T. asahii's cellular stress response, including resistance to heat, oxidative damage, and antifungal agents.
  • The Hog1 pathway is critical for T. asahii's virulence and survival within the host.
  • Targeting Hog1 could be a potential strategy for treating T. asahii infections.

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