Chen Peiming, Zhang Xiaoping, Jia Lee, Prud'homme Robert K, Szekely Zoltan, Sinko Patrick J
Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, 160 Frelinghuysen Road, Piscataway, NJ 08854, USA.
Cancer Metastasis Alert and Prevention Center, College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350002, China.
J Control Release. 2014 Nov 28;194:341-9. doi: 10.1016/j.jconrel.2014.09.006. Epub 2014 Sep 16.
Macrophages are involved in a number of diseases, such as HIV infection/AIDS, tuberculosis, tumor development and atherosclerosis. Macrophages possess several cell surface receptors (e.g., the mannose receptor, MR) that may serve as drug delivery cellular portals for nanocarriers (NCs). In this study, the optimal structural configuration for cell uptake of mannosylated poly(ethylene glycol)-conjugate type NCs was determined. A series of NCs were synthesized to systematically evaluate the effects of the number of mannose units (Man), the PEG carrier size and the mPEG spacer length between adjacent mannose units on NC uptake into MR-expressing J774.E murine macrophage-like cells. Among NCs with 0, 1, 2 or 4 units of mannose, the uptake of (Man)2-NC was the highest, suggesting a trade-off between avidity and NC-MR clustering on the cell surface that sterically hinders endocytosis. This optimal (Man)2-NC configuration was built into subsequent NCs to optimize the other two parameters, PEG carrier size and spacer length. NCs with 0, 5, 12, 20, 30 or 40 kDa linear PEG carriers showed an inverse relationship between PEG size and uptake. The 12 kDa PEG carrier was chosen for investigating the third parameter, the Man-Man distance, since it may represent the best trade off (i.e., tissue penetration vs. systemic clearance) for in vivo macrophage targeting. Three (Man)2-PEG12kDa NCs with different Man-Man distances (39, 56 or 89Å) were synthesized. The uptake of the NC with the 56Å distance between mannoses was four- and two-fold higher than NCs with 39Å and 89Å distances, respectively. Confocal microscopy confirmed that the optimized (Man)2-PEG12kDa NC with the 56Å Man-Man distance was internalized via endocytosis consistent with temperature-dependent active uptake. In conclusion, the optimal NC structural parameters for targeting the MR on macrophage-like J774.E cells are (i) a small PEG polymer carrier, (ii) two mannose units per NC and (iii) a 56Å distance between adjacent mannose units.
巨噬细胞参与多种疾病，如HIV感染/艾滋病、结核病、肿瘤发展和动脉粥样硬化。巨噬细胞拥有多种细胞表面受体（如甘露糖受体，MR），这些受体可作为纳米载体（NCs）的药物递送细胞通道。在本研究中，确定了甘露糖基化聚乙二醇缀合型NCs细胞摄取的最佳结构构型。合成了一系列NCs，以系统评估甘露糖单元数量（Man）、PEG载体大小以及相邻甘露糖单元之间的mPEG间隔长度对表达MR的J774.E小鼠巨噬细胞样细胞摄取NCs的影响。在具有0、1、2或4个甘露糖单元的NCs中，(Man)2-NC的摄取量最高，这表明在亲和力与细胞表面NC-MR聚集之间存在权衡，而这种聚集在空间上阻碍了内吞作用。将这种最佳的(Man)2-NC构型应用于后续的NCs，以优化其他两个参数，即PEG载体大小和间隔长度。具有0、5、12、20、30或40 kDa线性PEG载体的NCs显示出PEG大小与摄取之间呈反比关系。选择12 kDa的PEG载体来研究第三个参数，即Man-Man距离，因为它可能代表体内巨噬细胞靶向中最佳的权衡（即组织渗透与全身清除）。合成了三种具有不同Man-Man距离（39、56或89Å）的(Man)2-PEG12kDa NCs。甘露糖之间距离为56Å的NC的摄取量分别比距离为39Å和89Å的NC高4倍和2倍。共聚焦显微镜证实，具有56Å Man-Man距离的优化(Man)2-PEG12kDa NC通过与温度依赖性主动摄取一致的内吞作用被内化。总之，靶向巨噬细胞样J774.E细胞上MR的最佳NC结构参数为：（i）小PEG聚合物载体；（ii）每个NC两个甘露糖单元；（iii）相邻甘露糖单元之间56Å的距离。
