Influence of 17β-estradiol on gene expression of paracoccidioides during mycelia-to-yeast transition

Abstract

Background: Paracoccidioides is the causative agent of paracoccidioidomycosis, a systemic mycosis endemic to Latin America. Infection is initiated by inhalation of conidia (C) or mycelial (M) fragments, which subsequently differentiate into yeast (Y). Epidemiological studies show a striking predominance of paracoccidioidomycosis in adult men compared to premenopausal women. In vitro and in vivo studies suggest that the female hormone (17β-estradiol, E 2) regulates or inhibits M-or-C-to-Y transition. In this study we have profiled transcript expression to understand the molecular mechanism of how E 2 inhibits M-to-Y transition. Methodology: We assessed temporal gene expression in strain Pb01 in the presence or absence of E 2 at various time points through 9 days of the M-to-Y transition using an 11,000 element random-shear genomic DNA microarray and verified the results using quantitative real time-PCR. E 2-regulated clones were sequenced to identify genes and biological function. Principal Findings: E 2-treatment affected gene expression of 550 array elements, with 331 showing up-regulation and 219 showing down-regulation at one or more time points (p≤0.001). Genes with low expression after 4 or 12 h exposure to E 2 belonged to pathways involved in heat shock response (hsp90 and hsp70), energy metabolism, and several retrotransposable elements. Y-related genes, α-1,3-glucan synthase, mannosyltransferase and Y20, demonstrated low or delayed expression in E 2-treated cultures. Genes potentially involved in signaling, such as palmitoyltransferase (erf2), small GTPase RhoA, phosphatidylinositol-4-kinase, and protein kinase (serine/threonine) showed low expression in the presence of E 2, whereas a gene encoding for an arrestin domain-containing protein showed high expression. Genes related to ubiquitin-mediated protein degradation, and oxidative stress response genes were up-regulated by E 2. Conclusion: This study characterizes the effect of E 2 at the molecular level on the inhibition of the M-to-Y transition and is indicative that the inhibitory actions of E 2 may be working through signaling genes that regulate dimorphism. © 2011 Shankar et al.