Oliveira Francisco Odencio Rodrigues de, Alves Carlos Roberto, Calvet Cláudia Magalhães, Toma Leny, Bouças Rodrigo Ippolito, Nader Helena Bociani, Castro Côrtes Luzia Monteiro de, Krieger Marco Aurélio, Meirelles Maria de Nazareth S L, Souza Pereira Mirian Claudia de
Laboratório de Ultra-estrutura Celular, IOC/FIOCRUZ, Av. Brasil 4365, Manguinhos, 21040-900 Rio de Janeiro, RJ, Brazil.
Microb Pathog. 2008 Apr;44(4):329-38. doi: 10.1016/j.micpath.2007.10.003. Epub 2007 Oct 22.
Trypanosoma cruzi invasion is mediated by receptor-ligand recognition between the surfaces of both parasite and target cell. We have previously demonstrated the role of heparan sulfate proteoglycan in the attachment and invasion of T. cruzi in cardiomyocytes. Herein, we have isolated the T. cruzi heparin-binding proteins (HBP-Tc) and investigated the nature of cardiomyocyte heparan sulfate (HS)-binding site to the parasite surface ligand. Two major heparin-binding proteins with molecular masses of 65.8 and 59 kDa were observed in total extract of amastigote and trypomastigote forms of T. cruzi. Hydrophobic [S(35)]methionine labeled proteins eluted from heparin-sepharose affinity chromatography also revealed both proteins in trypomastigotes but only the 59 kDa is strongly recognized by biotin-conjugated glycosaminoglycans. Competition assays were performed to analyze the role of sulfated proteoglycans, including heparin, keratan sulfate and both acetylated and highly sulfated domains of heparan sulfate, in the recognition and invasion process of T. cruzi. Significant inhibitions of 84% and 35% in the percentage of infection were revealed after treatment of the parasites with heparin and the N-acetylated/ N-sulfated heparan sulfate domain, respectively, suggesting the important role of the glycuronic acid and NS glucosamine domain of the HS chain in the recognition of the HBP-Tc during the T. cruzi-cardiomyocyte interaction.
克氏锥虫的入侵是由寄生虫和靶细胞表面之间的受体 - 配体识别介导的。我们之前已经证明了硫酸乙酰肝素蛋白聚糖在克氏锥虫附着和侵入心肌细胞中的作用。在此，我们分离了克氏锥虫肝素结合蛋白（HBP - Tc），并研究了心肌细胞硫酸乙酰肝素（HS）与寄生虫表面配体结合位点的性质。在克氏锥虫无鞭毛体和锥鞭毛体形式的总提取物中观察到两种主要的肝素结合蛋白，分子量分别为65.8 kDa和59 kDa。从肝素 - 琼脂糖亲和色谱中洗脱的疏水性[S(35)]甲硫氨酸标记蛋白在锥鞭毛体中也显示出这两种蛋白，但只有59 kDa的蛋白能被生物素偶联的糖胺聚糖强烈识别。进行了竞争试验，以分析硫酸化蛋白聚糖，包括肝素、硫酸角质素以及硫酸乙酰肝素的乙酰化和高度硫酸化结构域，在克氏锥虫识别和入侵过程中的作用。用肝素和N - 乙酰化/N - 硫酸化硫酸乙酰肝素结构域处理寄生虫后，感染百分比分别显著抑制了84%和35%，这表明在克氏锥虫与心肌细胞相互作用过程中，HS链的葡萄糖醛酸和NS葡糖胺结构域在识别HBP - Tc中起重要作用。
