Cherukuri Pavan Kumar, Songkiatisak Preeyaporn, Ding Feng, Jault Jean-Michel, Xu Xiao-Hong Nancy
Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, Virginia 23529, United States.
UMR5086 CNRS/UCBLyon I, MMSB-IBCP, 7 Passage du Vercors, 69367 Lyon cedex 07, France.
ACS Omega. 2020 Jan 13;5(3):1625-1633. doi: 10.1021/acsomega.9b03698. eCollection 2020 Jan 28.
Multidrug membrane transporters can extrude a wide range of substrates, which cause multidrug resistance and ineffective treatment of diseases. In this study, we used three different sized antibiotic drug nanocarriers to study their size-dependent inhibitory effects against . We functionalized 2.4 ± 0.7, 13.0 ± 3.1, and 92.6 ± 4.4 nm silver nanoparticles (Ag NPs) with a monolayer of 11-amino-1-undecanethiol and covalently linked them with antibiotics (ofloxacin, Oflx). The labeling ratios of antibiotics with NPs are 8.6 × 10, 9.4 × 10, and 6.5 × 10 Oflx molecules per NP, respectively. We designed cell culture medium in which both BmrA and ΔBmrA cells grew and functioned normally while ensuring the stabilities of nanocarriers (nonaggregation). These approaches allow us to quantitatively study the dependence of their inhibitory effect against two isogenic strains of , WT (normal expression of BmrA) and ΔBmrA (deletion of ), upon the NP size, antibiotic dose, and BmrA expression. Our results show that the inhibitory effects of nanocarriers highly depend on NP size and antibiotic dose. The same amount of Oflx on 2.4 ± 0.7, 13.0 ± 3.1, and 92.6 ± 4.4 nm nanocarriers shows the 3× lower, nearly the same, and 10× higher inhibitory effects than that of free Oflx, against both WT and ΔBmrA, respectively. Control experiments of the respective sized AgMUNH NPs (absence of Oflx) show insignificant inhibitory effects toward both strains. Taken together, the results show multiple factors, such as labeling ratios, multivalent effects, and pharmacodynamics (Oflx localization and distribution), which might play the roles in the size-dependent inhibitory effects on the growth of both WT and ΔBmrA strains. Interestingly, the inhibitory effects of nanocarriers are independent of the expression of BmrA, which could be attributed to the higher efflux of nanocarriers by other membrane transporters in both strains.
多药膜转运蛋白可以排出多种底物，这会导致多药耐药性以及疾病治疗无效。在本研究中，我们使用了三种不同尺寸的抗生素药物纳米载体来研究它们对……的尺寸依赖性抑制作用。我们用单层的11 - 氨基 - 1 - 十一烷硫醇对尺寸分别为2.4±0.7、13.0±3.1和92.6±4.4纳米的银纳米颗粒（Ag NPs）进行功能化，并将它们与抗生素（氧氟沙星，Oflx）共价连接。抗生素与纳米颗粒的标记比例分别为每纳米颗粒8.6×10、9.4×10和6.5×10个Oflx分子。我们设计了细胞培养基，其中BmrA和ΔBmrA细胞都能正常生长和发挥功能，同时确保纳米载体的稳定性（不聚集）。这些方法使我们能够定量研究它们对两种同基因菌株，即野生型（WT，正常表达BmrA）和ΔBmrA（缺失……）的抑制作用对纳米颗粒尺寸、抗生素剂量和BmrA表达的依赖性。我们的结果表明，纳米载体的抑制作用高度依赖于纳米颗粒尺寸和抗生素剂量。相同量的Oflx负载在尺寸为2.4±0.7、13.0±3.1和92.6±4.4纳米的纳米载体上，对野生型和ΔBmrA的抑制作用分别比游离Oflx低3倍、几乎相同以及高10倍。相应尺寸的AgMUNH纳米颗粒（不含Oflx）的对照实验对两种菌株均显示出微不足道的抑制作用。综上所述，结果表明多种因素，如标记比例、多价效应和药效学（Oflx的定位和分布），可能在对野生型和ΔBmrA菌株生长的尺寸依赖性抑制作用中发挥作用。有趣的是，纳米载体的抑制作用与BmrA的表达无关，这可能归因于两种菌株中其他膜转运蛋白对纳米载体的更高外排作用。
