The transcriptional profile of Trichophyton rubrum co-cultured with human keratinocytes shows new insights about gene modulation by terbinafine.

Purpose: Evaluate the effect of terbinafine in T. rubrum gene expression using a co-culture model in conjunction with RNA-seq Methods: T. rubrum and HaCat cells line were co-cultured in RPMI medium supplemented with 5% of fetal bovine serum and treated with 0.0162 µM of terbinafine.The co-culture was incubated for 24 h at 37ºC in a humidified atmosphere containing 5% CO2 , followed RNA by extraction of both organisms, libraries construction and sequence. Results: Our data demonstrated the modulation of several T. rubrum genes involved in the biosynthesis of ergosterol in addition to the target gene of terbinafine that is already known, genes encoding MFS- and ABC-type membrane transporters that are associated with the phenomenon of multidrug resistance, genes that have been discussed in the literature as possible novel targets for antifungal compounds and genes which do not have a known function in T. rubrum yet, but have been modulated in response to the drug. Conclusions: RNA-seq sequencing of the T. rubrum co-culture in the presence of terbinafine showed that several genes of the ergosterol biosynthesis cascade were repressed. We highlight the induction of transmembrane transporters, which may be associated with the efflux of this allylamine. In addition, other genes that could be involved in the pathogenicity of T. rubrum were also modulated in the presence of the drug. In addition, we observed the modulation of hypothetical genes with still unknown functions in T. rubrum but that possess orthologs in other dermatophytes. The present study is the first to evaluate the effect of terbinafine using a co-culture model of T. rubrum with human keratinocytes in conjunction with a large-scale sequencing technique. The results of large-scale analysis of the expression profile of T. rubrum co-cultured with human keratinocytes indicate that terbinafine can act on various targets related to the physiology of T. rubrum other than its main target of ergosterol biosynthetic pathway.These findings offer new perspectives for the discovery of novel antifungal targets or even for structural modifications in the terbinafine molecule that would allow to increase its spectrum of antifungal activity.