Chudzik Barbara, Koselski Mateusz, Czuryło Aleksandra, Trębacz Kazimierz, Gagoś Mariusz
Department of Cell Biology, Institute of Biology and Biochemistry, Maria Curie-Skłodowska University, 20-033, Lublin, Poland,
Eur Biophys J. 2015 Feb;44(1-2):77-90. doi: 10.1007/s00249-014-1003-8. Epub 2015 Jan 4.
Amphotericin B (AmB) is an antifungal polyene for which the most accepted mode of action is formation of protein-like ion channels in the cell membrane. Patch-clamp research on Candida albicans protoplasts carried out in the outside-out configuration showed that application of 0.05 and 0.1 μM AmB caused a decrease in seal resistance. Such a phenomenon can be correlated with a decrease in membrane tightness. AmB applied at a 0.05 μM concentration also caused a decrease in the number of active TOK1 (two-pore outward rectifiers) potassium channels, but did not significantly change their open probability. The results indicate that in C. albicans protoplast AmB causes a decrease in cell membrane integrity by interaction with its lipid phase but not with ion channels. Fluorescence microscopy techniques showed that AmB treatment, in clinical concentrations, had no effect on the percentage of PI-positive protoplasts. AmB treatment in the concentrations tested did not cause a rapid reduction of the number of C. albicans protoplasts. However, there was a significant loss of replication competency and numerous morphological and physiological disorders, including cytoplasm shrinking, abnormal morphology of the nucleus and mitochondria, a sudden decrease in the MTT reduction level and oxidative stress. Our results show that the induction of yeast cell death by AmB, at therapeutic doses, is a multistage and long-term process involving multiple intracellular pathways.
两性霉素B(AmB)是一种抗真菌多烯类药物,其最被认可的作用方式是在细胞膜中形成类似蛋白质的离子通道。对白色念珠菌原生质体进行的外向膜片钳研究表明,施加0.05和0.1μM的AmB会导致封接电阻降低。这种现象可能与膜紧密性的降低有关。以0.05μM的浓度施加AmB也会导致活性TOK1(双孔外向整流器)钾通道数量减少,但不会显著改变其开放概率。结果表明,在白色念珠菌原生质体中,AmB通过与其脂质相相互作用而非与离子通道相互作用导致细胞膜完整性降低。荧光显微镜技术表明,临床浓度的AmB处理对PI阳性原生质体的百分比没有影响。在所测试的浓度下,AmB处理并未导致白色念珠菌原生质体数量迅速减少。然而,存在显著的复制能力丧失以及许多形态和生理紊乱,包括细胞质收缩、细胞核和线粒体形态异常、MTT还原水平突然降低以及氧化应激。我们的结果表明,治疗剂量的AmB诱导酵母细胞死亡是一个涉及多个细胞内途径的多阶段长期过程。