Fritzsche Juliane, Alban Susanne, Ludwig Ralf J, Rubant Simone, Boehncke Wolf-Henning, Schumacher Gabriele, Bendas Gerd
Institute of Pharmaceutical Chemistry, Rheinische Friedrich Wilhelms University Bonn, Germany.
Biochem Pharmacol. 2006 Aug 14;72(4):474-85. doi: 10.1016/j.bcp.2006.05.006. Epub 2006 May 13.
Selectin-mediated leukocyte rolling along the endothelium is of key importance for maintaining the cellular immune response. The anti-inflammatory activities of heparin have partly been related to inhibition of P-selectin binding. Heparin, however, suffers from its heterogeneous variable structure, the animal origin and multiple in vivo effects. As P-selectin is a promising target for anti-inflammatory approaches, we focused on P-selectin inhibition by other sulfated polysaccharides and compared them with six heparins. We examined 15 structurally defined semisynthetic sulfated glucans, non-animal-derived from the linear glucans phycarin, curdlan or pullulan. The derivatives gradually differ in their degree of sulfation, molecular weight, and glycosidic linkage. The inhibitory capacity was analysed in a parallel plate flow chamber, detecting the rolling of U937 cells on P-selectin layers. Unfractionated heparins displayed variabilities between different preparations. Considering fractionated heparins, exceeding of a minimal mass is essential for activity. Comparing the glucan sulfates, charge density is the most important parameter for P-selectin binding. Highly sulfated derivatives are excellent inhibitors, the reduced cell binding up to 16.2+/-6.4% strongly exceeded the heparin activities. Molecular weight is of minor effects, while glycosidic backbone linkage holds certain importance. To check the P-selectin inhibition in vivo, heparin and one phycarin sulfate were tested using intravital microscopy of microvasculature in mice. Both compounds significantly reduced the rolling fractions of activated platelets on endothelium as effective as a blocking P-selectin antibody. Our study indicates that semisynthetic glucan sulfates with optimal structures block P-selectin excellently and might become promising candidates for anti-inflammatory drugs to replace heparin for certain applications.
选择素介导的白细胞在内皮细胞上滚动对于维持细胞免疫反应至关重要。肝素的抗炎活性部分与抑制P-选择素结合有关。然而，肝素存在结构异质性、动物来源以及多种体内效应等问题。由于P-选择素是抗炎方法的一个有前景的靶点，我们专注于其他硫酸化多糖对P-选择素的抑制作用，并将它们与六种肝素进行比较。我们研究了15种结构明确的半合成硫酸化葡聚糖，它们非动物来源，由线性葡聚糖phycarin、凝胶多糖或支链淀粉衍生而来。这些衍生物在硫酸化程度、分子量和糖苷键方面逐渐有所不同。在平行板流动腔中分析抑制能力，检测U937细胞在P-选择素层上的滚动情况。未分级肝素在不同制剂之间表现出变异性。考虑分级肝素时，超过最小质量对于活性至关重要。比较硫酸化葡聚糖时，电荷密度是P-选择素结合的最重要参数。高度硫酸化的衍生物是优秀的抑制剂，细胞结合减少高达16.2±6.4%，大大超过了肝素的活性。分子量影响较小，而糖苷主链连接具有一定重要性。为了在体内检测P-选择素抑制作用，使用小鼠微血管活体显微镜对肝素和一种phycarin硫酸盐进行了测试。两种化合物都显著降低了活化血小板在内皮细胞上的滚动分数，效果与阻断P-选择素抗体相当。我们的研究表明，具有最佳结构的半合成硫酸化葡聚糖能出色地阻断P-选择素，可能成为抗炎药物的有前景候选物，在某些应用中取代肝素。
