Abstract

Paracoccidioides brasiliensis is a dimorphic and thermo-regulated fungus which is the causative agent of paracoccidioidomycosis (PCM), an endemic disease widespread in Latin America that affects 10 million individuals. The mycosis has also been reported among patients with AIDS. The conventional drugs used for treatment of PCM are sulfonamides, amphotericin B and imidazole derivatives such as ketoconazole, itraconazole and fluconazole. The mechanism of action of these drugs has been investigated. However, no studies were also carried out for P. brasiliensis yet. Antifungal agents exert their activity through a variety of mechanisms, some of which are poorly understood. Novel approaches to characterize the mechanism of action of antifungal agents will be of great use in the antifungal drug development process. The aim of the current study was the identification of up and down regulated genes from P. brasiliensis after 1 hour and 2 hours of exposition to itraconazole and sulfametoxazole. By analyzing transcriptional profile and the validation of the genes, we identified genes described as regulated in other microorganisms in the presence of these drugs. However, other new genes were identified. To sulfametoxazole, several transcripts related to mitochondrial function were down regulated. Sulfa drugs act by competitive inhibition of the enzyme dihydropteroate synthase, a key enzyme involved in folate synthesis, which is required for mitochondrial protein synthesis. Triazole drugs act by blocking the ergosterol, an essential cell membrane component, biosynthetic pathway through binding to and inhibition of the lanosterol 14-α demethylase enzyme, encoded by the erg11. In this study, most of the regulated genes were involved in lipid metabolism including the precursors of ergosterol. The genes erg11, erg6, erg5 and erg3 were up regulated. In addition, were found genes involved in cell stress response, drug efflux, small molecule transport, elongation and transcription factors, cell wall and membrane, and hypothetic proteins, which had not yet been identified as responsive to these drugs. These data shed light on the mechanism of action of these classes of antifungal agents and demonstrate the potential utility of gene expression profiling in antifungal drug development.਀ Financial Support: CNPq, FINEP.਀㰀⼀昀漀渀琀㸀㰀⼀瀀㸀㰀戀爀㸀㰀戀㸀䬀攀礀眀漀爀搀㨀 㰀⼀戀㸀☀渀戀猀瀀㬀䄀渀琀椀昀甀渀最愀氀Ⰰ 䐀爀甀最猀Ⰰ 倀愀爀愀挀漀挀挀椀搀椀漀椀搀攀猀 戀爀愀猀椀氀椀攀渀猀椀猀Ⰰ 吀爀愀渀猀挀爀椀瀀琀椀漀渀愀氀 愀渀愀氀礀猀椀猀㰀⼀琀搀㸀㰀⼀琀爀㸀㰀⼀琀愀戀氀攀㸀㰀⼀琀爀㸀㰀⼀琀搀㸀㰀⼀琀愀戀氀攀㸀㰀⼀戀漀搀礀㸀㰀⼀栀琀洀氀㸀