Expressão gênica de Candida albicans frente a diferentes concentrações de antifúngicos e antiretrovirais

Abstract

Important attributes associated to virulence may be observed in Candida spp., such as the expression of SAP genes which are responsible for regulating the secretion of aspartate proteases (Sapp). It is known that exposure of Candida spp. to certain substances may alter the secretion pattern of hydrolytic enzymes, such as Sapp. These proteases have a chemical structure and active site similar to HIV virus proteases, suggesting that protease inhibitors used in the treatment of AIDS may interact with the proteases of Candida spp. and influence the synthesis of proteases. The standard isolate of C. albicans SC5314 and two isolates of C. albicans from hospital infection cases classified as sensitive to fluconazole and amphotericin B in the sensitivity test were cultured for 24 hours, 37°C, 180 rpm in Yeast Carbon Base (YCB) supplemented with bovine serum albumin (BSA) under different exposure conditions, such as the presence of fluconazole and amphotericin B in inhibitory and subinhibitory concentrations and saquinavir and pepstatin A in effective and sub-effective concentrations. The expression of the SAP2, SAP4, SAP7 and SAP9 genes in the isolates submitted to these cultures was evaluated using ACT1 as the normalizing gene and results were analyzed by the comparative CT method (2-ΔΔCT) method using the untreated sample as a control. SAP expression in C. albicans isolates was higher in the presence of inhibitory/effective concentrations of antifungal and protease inhibitors, and in absolute numbers the expression of these genes was even greater for protease inhibitors. C. albicans SC5314 was the highest expression isolate of SAP e SAP7 was the most expressed gene in the isolates, in absolute numbers. In order to investigate the influence of the active substances cultures were evaluated by flow cytometric and ergosterol quantification. Flow cytometric assessment did not demonstrate large changes in cell complexity or fluorescence drift indicative of increased death activity, and ergosterol quantification was significantly reduced The evaluation of the samples by flow cytometry didn’t show pronounced changes in cell complexity or fluorescence drift indicative of increased death activity in relation to the control only in the presence of fluconazole inhibitory concentration. These results suggest that there shouldn’t be direct relationship between the influence of antifungal and protease inhibitors on the expression of SAP and the assessed cellular patterns, however, since factors associated with virulence are correlated, such situations can positively influence the expression of genes in the sense of promoting protease replacement in order to ensure its pathogenicity.