PDF(Pubmed)
Abstract：
A large number of bacterial pathogens bind to host extracellular matrix (ECM) components. For example, many Gram-negative and Gram-positive pathogens express binding proteins for fibronectin (FN) on their cell surface. Mutagenesis studies of bacterial FN-binding proteins have demonstrated their importance in pathogenesis in preclinical animal models. However, means to draw on these findings to design therapeutic approaches that specifically target FN-bacteria interactions have not been successful because bacterial pathogens can elaborate several FN-binding proteins and also because FN is an essential protein and likely a nondruggable target. Here we report that select heparan compounds potently inhibit Streptococcus pneumoniae infection of injured corneas in mice. Using intact heparan sulfate (HS) and heparin (HP), heparinase-digested fragments of HS, HP oligosaccharides, and chemically or chemoenzymatically modified heparan compounds, we found that inhibition of S. pneumoniae corneal infection by heparan compounds is not mediated by simple charge effects but by a selective sulfate group. Removal of 2-O-sulfates significantly inhibited the ability of HP to inhibit S. pneumoniae corneal infection, whereas the addition of 2-O-sulfates to heparosan (H) significantly increased H\'s ability to inhibit bacterial corneal infection. Proximity ligation assays indicated that S. pneumoniae attaches directly to FN fibrils in the corneal epithelial ECM and that HS and HP specifically inhibit this binding interaction in a 2-O-sulfate-dependent manner. These data suggest that heparan compounds containing 2-O-sulfate groups protect against S. pneumoniae corneal infection by inhibiting bacterial attachment to FN fibrils in the subepithelial ECM of injured corneas. Moreover, 2-O-sulfated heparan compounds significantly inhibited corneal infection in immunocompromised hosts, by a clinical keratitis isolate of S. pneumoniae, and also when topically administered in a therapeutic manner. These findings suggest that the administration of nonanticoagulant 2-O-sulfated heparan compounds may represent a plausible approach to the treatment of S. pneumoniae keratitis.
摘要：
大量细菌病原体与宿主细胞外基质(ECM)组分结合。例如,许多革兰氏阴性和革兰氏阳性病原体在其细胞表面表达纤连蛋白(FN)的结合蛋白。细菌FN结合蛋白的诱变研究已证明其在临床前动物模型的发病机理中的重要性。然而,意味着利用这些发现来设计特异性靶向FN-细菌相互作用的治疗方法尚未成功，因为细菌病原体可以合成几种FN结合蛋白，也因为FN是必需蛋白，并且可能是不可药用的靶标。在这里，我们报道了选择的乙酰肝素化合物可有效抑制小鼠受损角膜的肺炎链球菌感染。使用完整的硫酸乙酰肝素（HS）和肝素（HP），肝素酶消化的HS片段，HP低聚糖,和化学或化学酶修饰的乙酰肝素化合物，我们发现,乙酰肝素化合物对肺炎链球菌角膜感染的抑制作用不是由简单的电荷效应介导的,而是由选择性硫酸基团介导的.去除2-O-硫酸盐显著抑制HP抑制肺炎链球菌角膜感染的能力,而在肝素原（H）中添加2-O-硫酸盐可显着提高H抑制细菌性角膜感染的能力。邻近连接测定表明，肺炎链球菌直接附着于角膜上皮ECM中的FN原纤维，并且HS和HP以2-O-硫酸盐依赖性方式特异性抑制这种结合相互作用。这些数据表明，含有2-O-硫酸盐基团的乙酰肝素化合物通过抑制细菌附着于受损角膜的上皮下ECM中的FN原纤维而防止肺炎链球菌角膜感染。此外，2-O-硫酸化乙酰肝素化合物显着抑制免疫受损宿主的角膜感染，由肺炎链球菌的临床角膜炎分离物，以及当以治疗方式局部施用时。这些发现表明，给予非抗凝2-O-硫酸化乙酰肝素化合物可能是治疗肺炎链球菌角膜炎的合理方法。
