Zhang Fuming, Wang Shaohui, Yang Jiyuan, Fraser Keith, Gibson James M, Wang Chunyu, Dordick Jonathan S, Tomatsidou Anastasia, Linhardt Robert J, Wang Lianchun, Sun Xingmin
Department of Chemical and Biological Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
Department of Molecular Medicine, Morsani College of Medicine, University of South Florida Tampa, FL 33620, USA.
Carbohydr Polym. 2025 Mar 1;351:123143. doi: 10.1016/j.carbpol.2024.123143. Epub 2024 Dec 12.
Clostridioides difficile (C. difficile) infection (CDI) is a life-threatening healthcare-associated infection occurring worldwide. C. difficile toxins (toxin A and toxin B) are the major virulence factors, causing CDI-related diarrhea and complications. Recent studies have shown that sulfated glycosaminoglcans (GAGs) are involved in mediating the cellular entry of these toxins. Although interactions between GAGs and toxins were reported, their binding kinetics and the structure features of glycans that facilitate toxin interaction have not been thoroughly studied. This research utilized surface plasmon resonance (SPR) to directly measure the kinetics of interactions between heparin and various toxins. Both toxin A and toxin B bind to heparin with high affinity (K = 3.3 nM and 13.5 nM, respectively). SPR competition assay showed that both toxin A and B prefer binding to longer heparin chains and that all sulfation on the heparin chain is crucial for the heparin-toxin interaction. Finally, an in vitro assay showed that heparin and non-anticoagulant heparin inhibit the cell rounding caused by toxin A in HeLa cells.
艰难梭菌（C. difficile）感染（CDI）是一种危及生命的医疗保健相关感染，在全球范围内均有发生。艰难梭菌毒素（毒素A和毒素B）是主要的毒力因子，可导致与CDI相关的腹泻和并发症。最近的研究表明，硫酸化糖胺聚糖（GAGs）参与介导这些毒素的细胞内吞。尽管已报道了GAGs与毒素之间的相互作用，但其结合动力学以及促进毒素相互作用的聚糖结构特征尚未得到充分研究。本研究利用表面等离子体共振（SPR）直接测量肝素与各种毒素之间相互作用的动力学。毒素A和毒素B均以高亲和力与肝素结合（K分别为3.3 nM和13.5 nM）。SPR竞争试验表明，毒素A和B均更倾向于与较长的肝素链结合，并且肝素链上的所有硫酸化对于肝素 - 毒素相互作用至关重要。最后，体外试验表明，肝素和非抗凝肝素可抑制HeLa细胞中由毒素A引起的细胞变圆。
