Effects of Argentilactone on the Transcriptional Profile, Cell Wall and Oxidative Stress of Paracoccidioides spp.

Abstract

Paracoccidioides spp., a dimorphic pathogenic fungus, is the etiologic agent of paracoccidioidomycosis (PCM). PCM is an endemic disease that affects at least 10 million people in Latin America, causing severe public health problems. The drugs used against pathogenic fungi have various side effects and limited efficacy; therefore, there is an inevitable and urgent medical need for the development of new antifungal drugs. In the present study, we evaluated the transcriptional profile of Paracoccidioides lutzii exposed to argentilactone, a constituent of the essential oil of Hyptis ovalifolia. A total of 1,058 genes were identified, of which 208 were up-regulated and 850 were down-regulated. Cell rescue, defense and virulence, with a total of 26 genes, was a functional category with a large number of genes induced, including heat shock protein 90 (hsp90), cytochrome c peroxidase (ccp), the hemoglobin ligand RBT5 (rbt5) and superoxide dismutase (sod). Quantitative real-time PCR revealed an increase in the expression level of all of those genes. An enzymatic assay showed a significant increase in SOD activity. The reduced growth of Pbhsp90-aRNA, Pbccp-aRNA, Pbsod-aRNA and Pbrbt5-aRNA isolates in the presence of argentilactone indicates the importance of these genes in the response of Paracoccidioides spp. to argentilactone. The response of the P. lutzii cell wall to argentilactone treatment was also evaluated. The results showed that argentilactone caused a decrease in the levels of polymers in the cell wall. These results suggest that argentilactone is a potential candidate for antifungal therapy.

Argentilactone Molecular Targets in Paracoccidioides brasiliensis Identified by Chemoproteomics

“…The reaction mixtures of the TCA cycle are composed of eight enzymes, some of which are associated with the enzymatic complexes of the mitochondrial matrix. In relation to the proteins of TCA, argentilactone interacted with fumarate hydratase and isocitrate dehydrogenase, all of which were then downregulated by P. lutzii in the presence of argentilactone (14,16). In addition, others proteins of the TCA cycle, such as citrate synthase, succinate dehydrogenase, and malate dehydrogenase, were also downregulated in the presence of argentilactone.…”

“…In addition, P. lutzii upregulated the proteins involved in cell rescue, defense, and stress response. Araújo et al used a transcriptome analysis as an experimental strategy to expand information about argentilactone's mode of action (16). That study suggested that argentilactone promoted dysfunction in mitochondrial membrane potential, leading to probable oxidative stress, and it may act on the cell wall.…”

Heat Shock Proteins in Histoplasma and Paracoccidioides

“…Hsp90 protein is an immunodominant antigen in Paracoccidioides spp. and is associated with responses that facilitate cellular survival in the setting of various environmental stresses (15,57,58,60,61). The fact that Hsp90 protein is linked to the transition from mycelium to yeast further supports the targeting of this protein in therapeutics.…”

“…In Paracoccidioides spp., Hsp90 protein regulates the proliferation and adaptation of the fungus to different environmental conditions (57,58), and it may assist yeast cells in coping with a variety of physiological stresses, including temperature, host interaction, and oxidative injury (15). For example, exposure of Paracoccidioides spp.…”

Comparative transcriptomic analysis of Listeria monocytogenes reveals upregulation of stress genes and downregulation of virulence genes in response to essential oil extracted from Baccharis psiadioides

“…Positive regulation of genes involved in the metabolism of several compounds may be related to the EO composition, since EO are complex mixtures of volatile substances, usually lipophilic, whose components include terpene hydrocarbons, simple alcohols, aldehydes, ketones, phenols, esters and fixed organic acids (Simões and Spitzer 1999). Araújo et al (2016) analyzed the effects of argentilactone, a constituent of the EO from Hyptis ovalifolia, on the transcriptional profile, cell wall and oxidative stress of Paracoccidioides spp., a dimorphic pathogenic fungus. Their results demonstrated that the upregulated genes were related to metabolism; cell rescue, defense and virulence; energy and cell cycle; and DNA processing.…”