Guangdong Province Key Laboratory of Molecule Immunology and Antibody Engineering, Guangdong, PR China.
Clinical Medicine Postdoctoral Mobile Station, Jinan University, Guangdong, PR China.
J Med Microbiol. 2014 Jul;63(Pt 7):988-996. doi: 10.1099/jmm.0.073890-0. Epub 2014 May 1.
We found that tetrandrine (TET) can reverse the resistance of Candida albicans to fluconazole (FLC) and that this interaction is associated with the inhibition of drug efflux pumps. Mitochondrial aerobic respiration, which plays a major role in C. albicans metabolism, is the primary source of ATP for cellular processes, including the activation of efflux pumps. However, it was unclear if TET exerts its synergistic action against C. albicans via its impact on the mitochondrial aerobic respiratory metabolism. To investigate this mechanism, we examined the impact of FLC in the presence or absence of TET on two C. albicans strains obtained from a single parental source (FLC-sensitive strain CA-1 and FLC-resistant strain CA-16). We analysed key measures of energy generation and conversion, including the activity of respiration chain complexes I and III (CI and CIII), ATP synthase (CV) activity, and the generation of reactive oxygen species (ROS), and studied intracellular ATP levels and the mitochondrial membrane potential (ΔΨm), which has a critical impact on energy transport. Mitochondrial morphology was observed by confocal microscopy. Our functional analyses revealed that, compared with strains treated only with FLC, TET+FLC increased the ATP levels and decreased ΔΨm in CA-1, but decreased ATP levels and increased ΔΨm in CA-16 (P<0.05). Additionally, CI, CIII and CV activity decreased by 23-48%. The production of ROS increased by two- to threefold and mitochondrial morphology was altered in both strains. Our data suggested that TET impacted mitochondrial aerobic respiratory metabolism by influencing the generation and transport of ATP, reducing the utilization of ATP, and resulting in the inhibition of drug efflux pump activity. This activity contributed to the synergistic action of TET on FLC against C. albicans.
我们发现汉防己甲素（TET）可以逆转白色念珠菌对氟康唑（FLC）的耐药性，这种相互作用与抑制药物外排泵有关。需氧呼吸是白色念珠菌代谢的主要方式，为细胞过程提供了主要的 ATP 来源，包括外排泵的激活。然而，TET 是否通过影响需氧呼吸代谢发挥其对白色念珠菌的协同作用尚不清楚。为了研究这种机制，我们研究了氟康唑（FLC）在存在或不存在汉防己甲素（TET）的情况下对两种来源于单一亲本源的白色念珠菌菌株（FLC 敏感株 CA-1 和 FLC 耐药株 CA-16）的影响。我们分析了能量产生和转化的关键指标，包括呼吸链复合物 I 和 III（CI 和 CIII）、ATP 合酶（CV）活性、活性氧（ROS）的产生，并研究了细胞内 ATP 水平和线粒体膜电位（ΔΨm），这对能量转运有重要影响。通过共聚焦显微镜观察线粒体形态。我们的功能分析表明，与仅用 FLC 处理的菌株相比，TET+FLC 增加了 CA-1 中的 ATP 水平并降低了ΔΨm，但降低了 CA-16 中的 ATP 水平并增加了ΔΨm（P<0.05）。此外，CI、CIII 和 CV 活性降低了 23-48%。ROS 的产生增加了两到三倍，两种菌株的线粒体形态都发生了改变。我们的数据表明，TET 通过影响 ATP 的产生和运输、减少 ATP 的利用来影响需氧呼吸代谢，从而抑制药物外排泵的活性。这种活性有助于 TET 对白色念珠菌的 FLC 的协同作用。
