Knorre Dmitry A, Besedina Elizaveta, Karavaeva Iuliia E, Smirnova Ekaterina A, Markova Olga V, Severin Fedor F
Belozersky Institute of Physico-Chemical Biology, Moscow State University, Leninskiye Gory 1-40, Moscow 119991, Russia
Faculty of Bioengineering and Bioinformatics, Moscow State University, Leninskiye Gory 1-73, Moscow 119991, Russia.
FEMS Yeast Res. 2016 Jun;16(4). doi: 10.1093/femsyr/fow030. Epub 2016 Apr 4.
ABC-transporters with broad substrate specificity are responsible for pathogenic yeast resistance to antifungal compounds. Here we asked whether highly hydrophobic chemicals with delocalized positive charge can be used to overcome the resistance. Such molecules efficiently penetrate the plasma membrane and accumulate inside the cells. We reasoned that these properties can convert an active efflux of the compounds into a futile cycle thus interfering with the extrusion of the antibiotics. To test this, we studied the effects of several alkylated rhodamines on the drug resistance of yeast Saccharomyces cerevisiae We found that octylrhodamine synergetically increases toxicity of Pdr5p substrate-clotrimazole, while the others were less effective. Next, we compared the contributions of three major pleiotropic ABC-transporters (Pdr5p, Yor1p, Snq2p) on the accumulation of the alkylated rhodamines. While all of the tested compounds were extruded by Pdr5p, Yor1p and Snq2p showed narrower substrate specificity. Interestingly, among the tested alkylated rhodamines, inactivation of Pdr5p had the strongest effect on the accumulation of octylrhodamine inside the cells, which is consistent with the fact that clotrimazole is a substrate of Pdr5p. As alkylated rhodamines were shown to be non-toxic on mice, our study makes them potential components of pharmacological antifungal compositions.
具有广泛底物特异性的ABC转运蛋白是致病性酵母对抗真菌化合物产生耐药性的原因。在此，我们探讨了带有离域正电荷的高度疏水性化学物质是否可用于克服这种耐药性。这类分子能有效穿透质膜并在细胞内蓄积。我们推断，这些特性可将化合物的主动外排转化为无效循环，从而干扰抗生素的外排。为验证这一点，我们研究了几种烷基化罗丹明对酿酒酵母耐药性的影响。我们发现辛基罗丹明可协同增强Pdr5p底物克霉唑的毒性，而其他几种则效果较差。接下来，我们比较了三种主要的多效性ABC转运蛋白（Pdr5p、Yor1p、Snq2p）对烷基化罗丹明蓄积的作用。虽然所有测试化合物均可被Pdr5p外排，但Yor1p和Snq2p显示出较窄的底物特异性。有趣的是，在测试的烷基化罗丹明中，Pdr5p失活对细胞内辛基罗丹明的蓄积影响最大，这与克霉唑是Pdr5p的底物这一事实相符。由于烷基化罗丹明对小鼠无毒，我们的研究表明它们有可能成为抗真菌药物组合物的成分。
