Candida haemulonii species complex (C. haemulonii, C. haemulonii var. vulnera and Candida duobushaemulonii) is composed by emerging and multidrug-resistant (MDR) yeasts. Candidiasis, the disease caused by these species, is difficult to treat and culminates in clinical failures and patient death. It is well-known that Candida peptidases play important roles in the fungus–host interactions, and hence these enzymes are promising targets for developing new antifungal drugs. Recently, serine-type peptidases were described in clinical isolates of C. haemulonii complex with the ability to cleave relevant key host proteins. Herein, the effects of serine peptidase inhibitors (SPIs) on the cell biology of this fungal complex were evaluated. Initially, eight distinct SPIs (phenylmethylsulfonyl fluoride – PMSF, 4-(2-aminoethyl) benzenesulfonyl fluoride hydrochloride – AEBSF, N-α-tosyl-l-lysine chloromethyl ketone hydrochloride – TLCK, N-p-tosyl-l-phenylalanine chloromethyl ketone – TPCK, simeprevir, boceprevir, danoprevir and telaprevir) were tested on the fungal growth. TPCK showed the best efficacy in controlling cell proliferation, being selected for the following experiments. This SPI induced changes in the architecture of yeast cells, as observed by scanning electron microscopy, besides injuries at the plasma membrane and reduction in the ergosterol content. TPCK also diminished the ability of yeasts to adhere to abiotic (polystyrene and glass) and biotic (murine macrophages) surfaces in a typically concentration-dependent manner. In addition, the 24 h-treatment of the mature biofilm promoted a decrease in biomass, viability and extracellular matrix. Altogether, our results highlight that SPIs may be promising new therapeutic agents in the treatment of candidiasis caused by emergent, opportunistic and MDR species forming the C. haemulonii complex.

Candida haemulonii物种复合体（C. haemulonii、C. haemulonii var. vulnera和Candida duobushaemulonii）由新兴和多重耐药 (MDR) 酵母组成。念珠菌病是由这些物种引起的疾病，难以治疗，最终导致临床失败和患者死亡。众所周知，念珠菌肽酶在真菌-宿主相互作用中起着重要作用，因此这些酶是开发新抗真菌药物的有希望的目标。最近，在C. haemulonii 的临床分离株中描述了丝氨酸型肽酶具有切割相关关键宿主蛋白的能力的复合物。在此，评估了丝氨酸肽酶抑制剂 (SPI) 对这种真菌复合物的细胞生物学的影响。最初，八个不同的SPI（苯甲基磺酰氟- PMSF，4-（2-氨基乙基）苯磺酰氟盐酸盐- AEBSF，Ñ -α甲苯磺酰基-升-赖氨酸氯甲基酮盐酸盐- TLCK，ñ - p甲苯磺酰升-苯丙氨酸氯甲基酮 – TPCK、simeprevir、boceprevir、danoprevir 和 telaprevir）对真菌生长进行了测试。TPCK在控制细胞增殖方面表现出最好的功效，被选用于以下实验。除了质膜损伤和麦角甾醇含量降低之外，通过扫描电子显微镜观察到，这种 SPI 还诱导了酵母细胞结构的变化。TPCK 还降低了酵母以典型的浓度依赖性方式粘附在非生物（聚苯乙烯和玻璃）和生物（鼠巨噬细胞）表面的能力。此外，成熟生物膜的 24 小时处理促进了生物量、活力和细胞外基质的减少。总而言之，我们的结果强调，SPIs 可能是治疗由紧急、C. haemulonii复合体。