A conserved dimorphism-regulating histidine kinase controls the dimorphic switching in Paracoccidioides brasiliensis

Author(s)

Chaves, Alison F. A. ; Navarro, Marina V. ; Castilho, Daniele G. ; Calado, Juliana C. P. ; Conceicao, Palloma M. ; Batista, Wagner L.

• Document type: Journal article
• Source: FEMS Yeast Research; v. 16, n. 5 AUG 2016.
• Web of Science Citations: 4

Abstract

Paracoccidioides brasiliensis and P. lutzii, thermally dimorphic fungi, are the causative agents of paracoccidioidomycosis (PCM). Paracoccidioides infection occurs when conidia or mycelium fragments are inhaled by the host, which causes the Paracoccidioides cells to transition to the yeast form. The development of disease requires conidia inside the host alveoli to differentiate into yeast cells in a temperature-dependent manner. We describe the presence of a two-component signal transduction system in P. brasiliensis, which we investigated by expression analysis of a hypothetical protein gene (PADG\_07579) that showed high similarity with the dimorphism-regulating histidine kinase (DRK1) gene of Blastomyces dermatitidis and Histoplasma capsulatum. This gene was sensitive to environmental redox changes, which was demonstrated by a dose-dependent decrease in transcript levels after peroxide stimulation and a subtler decrease in transcript levels after NO stimulation. Furthermore, the higher PbDRK1 levels after treatment with increasing NaCl concentrations suggest that this histidine kinase can play a role as osmosensing. In the mycelium-yeast (M -> Y) transition, PbDRK1 mRNA expression increased 14-fold after 24 h incubation at 37A degrees C, consistent with similar observations in other virulent fungi. These results demonstrate that the PbDRK1 gene is differentially expressed during the dimorphic M -> Y transition. Finally, when P. brasiliensis mycelium cells were exposed to a histidine kinase inhibitor and incubated at 37A degrees C, there was a delay in the dimorphic M -> Y transition, suggesting that histidine kinases could be targets of interest for PCM therapy. (AU)

• FAPESP's process: 15/09727-6 - Engineering and characterization of a mutant ””PbKU70 for the human pathogenic fungus Paracoccidioides brasiliensis
• Grantee: Alison Felipe Alencar Chaves
• Support type: Scholarships in Brazil - Doctorate
• FAPESP's process: 14/13961-1 - Role of secreted aspartyl protease (PbSAP) in virulence and dimorphism in the pathogenic fungus Paracoccidioides brasiliensis
• Grantee: Wagner Luiz Batista
• Support type: Regular Research Grants