Laboratório de Ultra-estrutura Celular, Instituto Oswaldo Cruz/FIOCRUZ, Av Brasil 4365, Manguinhos, Rio de Janeiro 21045-900, Brazil.
Parasitology. 2011 Apr;138(5):593-601. doi: 10.1017/S0031182010001678. Epub 2011 Jan 27.
Cell surface glycosaminoglycans (GAGs) play an important role in the attachment and invasion process of a variety of intracellular pathogens. We have previously demonstrated that heparan sulfate proteoglycans (HSPG) mediate the invasion of trypomastigote forms of Trypanosoma cruzi in cardiomyocytes. Herein, we analysed whether GAGs are also implicated in amastigote invasion. Competition assays with soluble GAGs revealed that treatment of T. cruzi amastigotes with heparin and heparan sulfate leads to a reduction in the infection ratio, achieving 82% and 65% inhibition of invasion, respectively. Other sulfated GAGs, such as chondroitin sulfate, dermatan sulfate and keratan sulfate, had no effect on the invasion process. In addition, a significant decrease in infection occurred after interaction of amastigotes with GAG-deficient Chinese Hamster Ovary (CHO) cells, decreasing from 20% and 28% in wild-type CHO cells to 5% and 9% in the mutant cells after 2 h and 4 h of infection, respectively. These findings suggest that amastigote invasion also involves host cell surface heparan sulfate proteoglycans. The knowledge of the mechanism triggered by heparan sulfate-binding T. cruzi proteins may provide new potential candidates for Chagas disease therapy.
细胞表面糖胺聚糖 (GAGs) 在多种细胞内病原体的附着和入侵过程中发挥重要作用。我们之前已经证明，硫酸乙酰肝素蛋白聚糖 (HSPG) 介导了 Trypanosoma cruzi 鞭毛体形式在心肌细胞中的入侵。在此，我们分析了 GAG 是否也参与了无鞭毛体的入侵。用可溶性 GAG 进行竞争实验表明，肝素和硫酸乙酰肝素处理无鞭毛体可导致感染率降低，分别达到 82%和 65%的入侵抑制率。其他硫酸化 GAG，如软骨素硫酸盐、硫酸皮肤素和硫酸角质素，对入侵过程没有影响。此外，无鞭毛体与 GAG 缺陷型中国仓鼠卵巢 (CHO) 细胞相互作用后，感染也显著减少，野生型 CHO 细胞中的感染率从 20%和 28%分别下降到突变细胞中的 5%和 9%，分别在感染 2 小时和 4 小时后。这些发现表明，无鞭毛体的入侵也涉及宿主细胞表面的硫酸乙酰肝素蛋白聚糖。对与肝素结合的 T. cruzi 蛋白触发机制的了解可能为恰加斯病的治疗提供新的潜在候选药物。
