Palmeira Vanila F, Kneipp Lucimar F, Rozental Sonia, Alviano Celuta S, Santos André L S
Laboratório de Estudos Integrados em Bioquímica Microbiana, Departamento de Microbiologia Geral, Instituto de Microbiologia Prof. Paulo de Góes, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
PLoS One. 2008;3(10):e3382. doi: 10.1371/journal.pone.0003382. Epub 2008 Oct 13.
Fonsecaea pedrosoi is the principal etiologic agent of chromoblastomycosis, a fungal disease whose pathogenic events are poorly understood. Current therapy for chromoblastomycosis is suboptimal due to toxicity of the available therapeutic agents and the emergence of drug resistance. Compounding these problems is the fact that endemic countries and regions are economically poor.
In the present work, we have investigated the effect of human immunodeficiency virus (HIV) peptidase inhibitors (PIs) on the F. pedrosoi conidial secreted peptidase, growth, ultrastructure and interaction with different mammalian cells. All the PIs impaired the acidic conidial-derived peptidase activity in a dose-dependent fashion, in which nelfinavir produced the best inhibitory effect. F. pedrosoi growth was also significantly reduced upon exposure to PIs, especially nelfinavir and saquinavir. PIs treatment caused profound changes in the conidial ultrastructure as shown by transmission electron microscopy, including invaginations in the cytoplasmic membrane, disorder and detachment of the cell wall, enlargement of fungi cytoplasmic vacuoles, and abnormal cell division. The synergistic action on growth ability between nelfinavir and amphotericin B, when both were used at sub-inhibitory concentrations, was also observed. PIs reduced the adhesion and endocytic indexes during the interaction between conidia and epithelial cells (CHO), fibroblasts or macrophages, in a cell type-dependent manner. Moreover, PIs interfered with the conidia into mycelia transformation when in contact with CHO and with the susceptibility killing by macrophage cells.
CONCLUSIONS/SIGNIFICANCE: Overall, by providing the first evidence that HIV PIs directly affects F. pedrosoi development and virulence, these data add new insights on the wide-spectrum efficacy of HIV PIs, further arguing for the potential chemotherapeutic targets for aspartyl-type peptidase produced by this human pathogen.
裴氏着色真菌是着色芽生菌病的主要病原体，这是一种致病性尚不明确的真菌病。由于现有治疗药物的毒性和耐药性的出现，目前针对着色芽生菌病的治疗并不理想。使这些问题更加复杂的是，流行国家和地区经济贫困。
在本研究中，我们研究了人类免疫缺陷病毒（HIV）蛋白酶抑制剂（PIs）对裴氏着色真菌分生孢子分泌的蛋白酶、生长、超微结构以及与不同哺乳动物细胞相互作用的影响。所有的蛋白酶抑制剂均以剂量依赖的方式损害酸性分生孢子衍生的蛋白酶活性，其中奈非那韦产生了最佳抑制效果。暴露于蛋白酶抑制剂后，裴氏着色真菌的生长也显著降低，尤其是奈非那韦和沙奎那韦。透射电子显微镜显示，蛋白酶抑制剂处理导致分生孢子超微结构发生深刻变化，包括细胞膜内陷、细胞壁紊乱和脱离、真菌细胞质空泡扩大以及异常细胞分裂。当奈非那韦和两性霉素B均以亚抑制浓度使用时，还观察到它们对生长能力的协同作用。蛋白酶抑制剂以细胞类型依赖的方式降低了分生孢子与上皮细胞（CHO）、成纤维细胞或巨噬细胞相互作用期间的黏附指数和内吞指数。此外，蛋白酶抑制剂在与CHO接触时干扰了分生孢子向菌丝体的转化，并影响了巨噬细胞的杀伤敏感性。
结论/意义：总体而言，通过提供HIV蛋白酶抑制剂直接影响裴氏着色真菌发育和毒力的首个证据，这些数据为HIV蛋白酶抑制剂的广谱疗效提供了新见解，进一步证明了这种人类病原体产生的天冬氨酸型蛋白酶作为潜在化疗靶点的可能性。
