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Inhibition of PbGP43 expression may suggest that gp43 is a virulence factor in Paracoccidioides brasiliensis

Isaura Torres1, Orville Hernandez, Diana Tamayo

  • 1Unidad de Biología Celular y Molecular, Corporación para Investigaciones Biológicas (CIB), Medellín, Colombia. isaurap10@gmail.com

Plos One
|July 23, 2013
PubMed

Insights

This study reduced glycoprotein 43 (gp43) expression in Paracoccidioides brasiliensis using antisense RNA technology. Silencing gp43 significantly lowered fungal pathogenicity in mice, suggesting gp43 contributes to disease development.

Area of Science:

  • Medical Mycology
  • Molecular Biology
  • Immunology

Background:

  • Glycoprotein 43 (gp43) is a key diagnostic antigen for paracoccidioidomycosis.
  • Its precise role in Paracoccidioides brasiliensis biology and pathogenesis remains largely unknown.
  • gp43 elicits immune responses and interacts with extracellular matrix proteins.

Purpose of the Study:

  • To investigate the function of gp43 in P. brasiliensis using genetic modification.
  • To assess the impact of reduced gp43 expression on fungal virulence and host immune response.

Main Methods:

  • Antisense RNA (aRNA) technology and Agrobacterium tumefaciens-mediated transformation were used to create stable PbGP43 mutants.
  • Real-time PCR, immunoblotting, and affinity-ligand assays quantified gp43 expression and binding.
  • In vitro macrophage assays and in vivo mouse infection models evaluated fungal pathogenicity.

Main Results:

  • PbGP43 aRNA mutants showed 80-85% reduction in gp43 expression.
  • Silenced mutants exhibited reduced binding to laminin and fibronectin.
  • In vitro, reduced yeast recovery and increased TNF-α production were observed with IFN-γ-stimulated macrophages.
  • In vivo, fungal burden in mice lungs was negligible, with decreased IL-10 and IL-6 levels.

Conclusions:

  • Reduced gp43 expression correlates with significantly lower pathogenicity in a mouse model.
  • gp43 likely plays a role in P. brasiliensis-host interactions and virulence.
  • Further studies with knockouts are needed for definitive proof.

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