Institute of Molecular Pharmacy, Pharmacenter, University of Basel, Switzerland.
J Microbiol Methods. 2010 Sep;82(3):249-55. doi: 10.1016/j.mimet.2010.06.015. Epub 2010 Jul 8.
Alpha-D-mannopyranosides are potent FimH antagonists, which inhibit the adhesion of Escherichia coli to highly mannosylated uroplakin Ia on the urothelium and therefore offer an efficient therapeutic opportunity for the treatment and prevention of urinary tract infection. For the evaluation of the therapeutic potential of FimH antagonists, their effect on the disaggregation of E. coli from Candida albicans and guinea pig erythrocytes (GPE) was studied. The mannose-specific binding of E. coli to yeast cells and erythrocytes is mediated by type 1 pili and can be monitored by aggregometry. Maximal aggregation of C. albicans or GPE to E. coli is reached after 600 s. Then the FimH antagonist was added and disaggregation determined by light transmission over a period of 1400 s. A FimH-deleted mutant of E. coli, which does not induce any aggregation, was used in a control experiment. The activities of FimH antagonists are expressed as IC(50)s, the half maximal inhibitory concentration of the disaggregation potential. n-Heptyl alpha-D-mannopyranoside (1) was used as a reference compound and exhibits an IC(50) of 77.14 microM , whereas methyl alpha-D-mannopyranoside (2) does not lead to any disaggregation at concentrations up to 800 microM. o-Chloro-p-[N-(2-ethoxy-3,4-dioxocyclobut-1-enyl)amino]phenyl alpha-D-mannopyranoside (3) shows a 90-fold and 2-chloro-4-nitrophenyl alpha-D-mannopyranoside (4) a 6-fold increased affinity compared to 1. Finally, 4-nitrophenyl alpha-D-mannopyranoside (5) exhibits an activity similar to 1. As negative control, D-galactose (6) was used. The standardized aggregation assay generates concentration-dependent, reproducible data allowing the evaluation of FimH antagonists according to their potency to inhibit E. coli adherence and can therefore be employed to select candidates for experimental and clinical studies for treatment and prevention of urinary tract infections.
α-D-甘露糖苷是有效的 FimH 拮抗剂，可抑制大肠埃希菌与尿路上皮高度甘露糖化尿路上皮素 Ia 的粘附，因此为治疗和预防尿路感染提供了有效的治疗机会。为了评估 FimH 拮抗剂的治疗潜力，研究了它们对大肠埃希菌从白色念珠菌和豚鼠红细胞（GPE）解聚的影响。大肠埃希菌与酵母细胞和红细胞的甘露糖特异性结合是由 1 型菌毛介导的，可以通过聚集测定法监测。白色念珠菌或 GPE 与大肠埃希菌最大聚集在 600 s 后达到。然后加入 FimH 拮抗剂，并在 1400 s 内通过透光率测定法确定解聚。在对照实验中使用不诱导任何聚集的大肠埃希菌 FimH 缺失突变体。FimH 拮抗剂的活性表示为 IC50，即解聚潜能的半最大抑制浓度。正庚基α-D-甘露糖苷（1）用作参考化合物，其 IC50 为 77.14 μM，而甲基α-D-甘露糖苷（2）在高达 800 μM 的浓度下不会导致任何解聚。邻氯-p-[N-（2-乙氧基-3,4-二氧环丁-1-烯基）氨基]苯基α-D-甘露糖苷（3）显示出 90 倍的亲和力，2-氯-4-硝基苯基α-D-甘露糖苷（4）显示出与 1 相比增加了 6 倍的亲和力。最后，4-硝基苯基α-D-甘露糖苷（5）表现出与 1 相似的活性。作为阴性对照，使用 D-半乳糖（6）。标准化的聚集测定法生成浓度依赖性、可重复的数据，允许根据其抑制大肠埃希菌粘附的效力评估 FimH 拮抗剂，因此可用于选择用于治疗和预防尿路感染的实验和临床研究的候选药物。
