PDF(Pubmed)
Abstract：
Porphyrinic photosensitizers (PSs) and their nano-sized polymer-based carrier systems are required to exhibit low dark toxicity, avoid side effects, and ensure high in vivo tolerability. Yet, little is known about the intracellular fate of PSs during the dark incubation period and how it is affected by nanoparticles. In a systematic study, high-resolution magic angle spinning NMR spectroscopy combined with statistical analyses was used to study the metabolic profile of cultured HeLa cells treated with different concentrations of PS chlorin e4 (Ce4) alone or encapsulated in carrier systems. For the latter, either polyvinylpyrrolidone (PVP) or the micelle-forming polyethylene glycol (PEG)-polypropylene glycol triblock copolymer Kolliphor P188 (KP) were used. Diffusion-edited spectra indicated Ce4 membrane localization evidenced by Ce4 concentration-dependent chemical shift perturbation of the cellular phospholipid choline resonance. The effect was also visible in the presence of KP and PVP but less pronounced. The appearance of the PEG resonance in the cell spectra pointed towards cell internalization of KP, whereas no conclusion could be drawn for PVP that remained NMR-invisible. Multivariate statistical analyses of the cell spectra (PCA, PLS-DA, and oPLS) revealed a concentration-dependent metabolic response upon exposure to Ce4 that was attenuated by KP and even more by PVP. Significant Ce4-concentration-dependent alterations were mainly found for metabolites involved in the tricarboxylic acid cycle and the phosphatidylcholine metabolism. The data underline the important protective role of the polymeric carriers following cell internalization. Moreover, to our knowledge, for the first time, the current study allowed us to trace intracellular PS localization on an atomic level by NMR methods.
摘要：
卟啉类光敏剂（PS）及其纳米尺寸的基于聚合物的载体系统需要表现出低的暗毒性，避免副作用,并确保高的体内耐受性。然而，人们对PSs在黑暗潜伏期的细胞内命运以及它如何受到纳米粒子的影响知之甚少。在系统的研究中，高分辨率幻角旋转NMR光谱结合统计分析用于研究用单独或封装在载体系统中的不同浓度的PS二氢卟啉e4（Ce4）处理的培养的HeLa细胞的代谢谱。对于后者,使用聚乙烯吡咯烷酮(PVP)或形成胶束的聚乙二醇(PEG)-聚丙二醇三嵌段共聚物KolliphorP188(KP)。扩散编辑的光谱表明Ce4膜定位由细胞磷脂胆碱共振的Ce4浓度依赖性化学位移扰动证明。该效果在KP和PVP存在下也可见,但不太明显。细胞光谱中PEG共振的出现指向KP的细胞内化，而对于保持NMR不可见的PVP，无法得出任何结论。细胞光谱的多元统计分析(PCA，PLS-DA,和oPLS）揭示了暴露于Ce4后的浓度依赖性代谢反应，该反应被KP减弱，而PVP则减弱。主要发现参与三羧酸循环和磷脂酰胆碱代谢的代谢物的Ce4浓度依赖性变化。数据强调了细胞内化后聚合物载体的重要保护作用。此外，根据我们的知识，第一次,当前的研究使我们能够通过NMR方法在原子水平上追踪细胞内PS的定位。
