Effects of 17<i>β</i>-Estradiol and Testosterone on <i>Nocardia</i> <i>brasiliensis</i> Gene Expression

Infection caused by Nocardia brasiliensis, known as actinomycetoma, occurs more frequently in men than in women. Several factors are involved in sex bias in infections between men and women. However, the molecular mechanisms underlying these differences are not completely understood. Sex steroid hormones play an important role in the development of infections because of their function in the host immune response and their direct effect on bacterial activity. Estrogen is generally understood to have a protective effect in women, whereas testosterone is associated with immunosuppression and predisposes men to many infections. This work aimed to study the in vitro effect of 17β-estradiol and testosterone on N. brasiliensis gene expression using a differential display assay, through RNA arbitrarily primed PCR. The results showed that both hormones affect the expression of genes encoding proteins involved in metabolism, transcriptional regulation, and other hypothetical proteins with unknown functions. Further studies are needed to better understand the exact role of these hormones in the N. brasiliensis virulence and pathogenesis of the infection, which may help in understanding the sex bias of this infection.