Bensikaddour Hayet, Snoussi Karim, Lins Laurence, Van Bambeke Françoise, Tulkens Paul M, Brasseur Robert, Goormaghtigh Erik, Mingeot-Leclercq Marie-Paule
Université Catholique de Louvain, Faculty of Medicine, Unité de Pharmacologie Cellulaire et Moléculaire, UCL 73.70, Avenue E. Mounier 73, B-1200 Bruxelles, Belgium.
Biochim Biophys Acta. 2008 Nov;1778(11):2535-43. doi: 10.1016/j.bbamem.2008.08.015. Epub 2008 Sep 6.
The interactions between a drug and lipids may be critical for the pharmacological activity. We previously showed that the ability of a fluoroquinolone antibiotic, ciprofloxacin, to induce disorder and modify the orientation of the acyl chains is related to its propensity to be expelled from a monolayer upon compression [1]. Here, we compared the binding of ciprofloxacin on DPPC and DPPG liposomes (or mixtures of phospholipids [DOPC:DPPC], and [DOPC:DPPG]) using quasi-elastic light scattering and steady-state fluorescence anisotropy. We also investigated ciprofloxacin effects on the transition temperature (T(m)) of lipids and on the mobility of phosphate head groups using Attenuated Total Reflection Fourier Transform Infrared-Red Spectroscopy (ATR-FTIR) and (31)P Nuclear Magnetic Resonance (NMR) respectively. In the presence of ciprofloxacin we observed a dose-dependent increase of the size of the DPPG liposomes whereas no effect was evidenced for DPPC liposomes. The binding constants K(app) were in the order of 10(5) M(-1) and the affinity appeared dependent on the negative charge of liposomes: DPPG>DOPC:DPPG (1:1; M:M)>DPPC>DOPC:DPPC (1:1; M:M). As compared to the control samples, the chemical shift anisotropy (Deltasigma) values determined by (31)P NMR showed an increase of 5 and 9 ppm for DPPC:CIP (1:1; M:M) and DPPG:CIP (1:1; M:M) respectively. ATR-FTIR experiments showed that ciprofloxacin had no effect on the T(m) of DPPC but increased the order of the acyl chains both below and above this temperature. In contrast, with DPPG, ciprofloxacin induced a marked broadening effect on the transition with a decrease of the acyl chain order below its T(m) and an increase above this temperature. Altogether with the results from the conformational analysis, these data demonstrated that the interactions of ciprofloxacin with lipids depend markedly on the nature of their phosphate head groups and that ciprofloxacin interacts preferentially with anionic lipid compounds, like phosphatidylglycerol, present at a high content in these membranes.
药物与脂质之间的相互作用可能对药理活性至关重要。我们之前表明，氟喹诺酮类抗生素环丙沙星诱导无序和改变酰基链取向的能力与其在压缩时从单层中被排出的倾向有关[1]。在此，我们使用准弹性光散射和稳态荧光各向异性比较了环丙沙星在二棕榈酰磷脂酰胆碱（DPPC）和二棕榈酰磷脂酰甘油（DPPG）脂质体（或磷脂混合物[二油酰磷脂酰胆碱：DPPC]和[二油酰磷脂酰胆碱：DPPG]）上的结合情况。我们还分别使用衰减全反射傅里叶变换红外光谱（ATR - FTIR）和³¹P核磁共振（NMR）研究了环丙沙星对脂质转变温度（T(m)）以及磷酸头部基团流动性的影响。在环丙沙星存在的情况下，我们观察到DPPG脂质体的尺寸呈剂量依赖性增加，而DPPC脂质体未显示出影响。结合常数K(app)约为10⁵ M⁻¹，且亲和力似乎取决于脂质体的负电荷：DPPG > 二油酰磷脂酰胆碱：DPPG（1:1；摩尔比：摩尔比）> DPPC > 二油酰磷脂酰胆碱：DPPC（1:1；摩尔比：摩尔比）。与对照样品相比，通过³¹P NMR测定的化学位移各向异性（Δσ）值显示，DPPC:环丙沙星（1:1；摩尔比：摩尔比）和DPPG:环丙沙星（1:1；摩尔比：摩尔比）分别增加了5 ppm和9 ppm。ATR - FTIR实验表明，环丙沙星对DPPC的T(m)没有影响，但在该温度以下和以上均增加了酰基链的有序性。相比之下，对于DPPG，环丙沙星在转变过程中诱导了明显的展宽效应，在其T(m)以下酰基链有序性降低，在该温度以上则增加。综合构象分析的结果，这些数据表明环丙沙星与脂质的相互作用明显取决于其磷酸头部基团的性质，并且环丙沙星优先与这些膜中高含量存在的阴离子脂质化合物（如磷脂酰甘油）相互作用。
