Antisense locked nucleic acid gapmers to control Candida albicans filamentation

Whereas locked nucleic acid (LNA) has been extensively used to control gene expression, it has never been exploited to control Candida virulence genes. Thus, the main goal of this work was to compare the efficacy of five different LNA-based antisense oligonucleotides (ASO) with respect to the ability to control EFG1 gene expression, to modulate filamentation and to reduce C. albicans virulence. In vitro, all LNA-ASOs were able to significantly reduce C. albicans filamentation and to control EFG1 gene expression. Using the in vivo Galleria mellonella model, important differences among the five LNA-ASOs were revealed in terms of C. albicans virulence reduction. The inclusion of PS-linkage and palmitoyl-2'-amino-LNA chemical modification in these five LNA gapmers proved to be the most promising combination, increasing the survival of G. mellonella by 40%. Our work confirms that LNA-ASOs are useful tools for research and therapeutic development in the candidiasis field.