Vavala Elisabetta, Mignogna Giuseppina, Spano Furio, Stringaro Annarita, Colone Marisa, Sanguinetti Maurizio, Maras Bruno, Angiolella Letizia
J Chemother. 2013 Dec;25(6):332-40. doi: 10.1179/1973947813Y.0000000091. Epub 2013 Dec 6.
Candida albicans cell wall constitutes a sensitive boundary that undergoes molecular changes upon environmental injuries. Antimycotics exert an intense action on cell wall eliciting both qualitative and quantitative changes of resident proteins. The emergence of drug resistance is marked by a modulation of cell wall proteomic profile. In this study, we monitored, at the proteome level through a two-dimensional gel electrophoresis-based approach, differences of cell wall proteins in sensitive and resistant strains of C. albicans, and variations occurring upon treatment of these strains with antifungal drugs. We identified Rhd3/Pga29, a glycophosphatidylinositol (GPI)-anchored protein, as the main over-expressed protein in micafungin resistant strain with respect to the sensitive control cells. A further increase of Rhd3/Pga29 took place when these resistant strains were treated with sub-lethal dose of micafungin. These results were also confirmed in other two clinical isolates resistant to caspofungin. Results were validated by Western blot analyses and RT-PCR and immunoelectron microscopy images confirmed the increase of the Rhd3/Pga29 on the cell wall as well as in the cytosolic compartment of the micafungin-treated resistant cells. Rhd3/Pga29 over-expression upon echinocandin treatment could represent a strategy of C. albicans to counteract the toxic action of this drug. A role of this protein has also been claimed in the virulence of the fungus, suggesting an involvement of Rhd3/Pga29 in the relationship between C. albicans and the host.
白色念珠菌细胞壁构成了一个敏感的边界，在受到环境损伤时会发生分子变化。抗真菌药物对细胞壁产生强烈作用，引发驻留蛋白的定性和定量变化。耐药性的出现以细胞壁蛋白质组学图谱的调节为标志。在本研究中，我们通过基于二维凝胶电泳的方法在蛋白质组水平上监测了白色念珠菌敏感菌株和耐药菌株中细胞壁蛋白的差异，以及用抗真菌药物处理这些菌株后发生的变化。我们鉴定出Rhd3/Pga29，一种糖基磷脂酰肌醇（GPI）锚定蛋白，是相对于敏感对照细胞在米卡芬净耐药菌株中主要过度表达的蛋白。当用亚致死剂量的米卡芬净处理这些耐药菌株时，Rhd3/Pga29进一步增加。这些结果在另外两株对卡泊芬净耐药的临床分离株中也得到了证实。通过蛋白质免疫印迹分析和逆转录-聚合酶链反应验证了结果，免疫电子显微镜图像证实了米卡芬净处理的耐药细胞的细胞壁以及胞质区室中Rhd3/Pga29的增加。棘白菌素处理后Rhd3/Pga29的过度表达可能代表白色念珠菌对抗该药物毒性作用的一种策略。该蛋白在真菌毒力方面也被认为具有作用，这表明Rhd3/Pga29参与了白色念珠菌与宿主之间的关系。
