Accumulation of Trehalose-6-Phosphate in Candida auris results in Decreased Echinocandin Resistance and Tolerance by Affecting Cell Wall Chitin Synthesis

The rise of multidrug-resistant fungal pathogens, like Candida auris, poses a significant public health challenge due to high mortality rates and the limited effectiveness of current treatment options. Echinocandins, targeting β-glucan synthesis, are the first-line therapy for invasive C. auris infections. However, the resistance to this drug class is increasing, underscoring the urgent need for new antifungal targets. This study investigates the role of trehalose biosynthesis in C. auris by either blocking biosynthesis of the intermediate molecule trehalose-6-phosphate (T6P), by disrupting the trehalose-phosphate synthase (Tps1), or blocking biosynthesis of trehalose, by disrupting the trehalose-6-phosphate phosphatase (Tps2). The tps2Δ strain demonstrated heightened susceptibility to echinocandins, while the tps1Δ and tps1Δ tps2Δ strains maintained resistance and tolerance levels comparable to the wild type (WT) strain. Subsequent analysis revealed a link between chitin biosynthesis and T6P levels. In the absence of T6P (in the tps1∆ or tps1∆tps2∆ strains) there was a strong increase in hexokinase activity and accelerated glycolysis, with no significant impact on chitin biosynthesis. However, the tps2Δ strain accumulated high levels of T6P, resulting in the inhibition of hexokinase and a reduced flux of glucose 6-phosphate into the chitin biosynthesis pathway, thereby significantly decreasing cell wall chitin content. The inability to compensate the reduction in β-glucan levels with increased chitin production during echinocandin treatment in the tps2Δ strain, rendered this strain highly susceptible to these drugs. Furthermore, an in vivo systemic infection model demonstrated that the tps2Δ strain exhibited a reduced fungal burden in tissues, with infected mice showing marked improvement during caspofungin treatment. This suggests that Tps2 is a putative target for improving echinocandin treatment and reducing virulence in C. auris.