Laboratorio de Zoonosis Parasitarias, Departamento de Biología, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata (UNMdP), Funes 3350, Nivel Cero, (7600) Mar del Plata, Argentina.
Int J Parasitol. 2010 May;40(6):651-61. doi: 10.1016/j.ijpara.2009.11.011. Epub 2009 Dec 22.
FK506 (tacrolimus) and polyketide macrolides such as rapamycin and its derivates bind to FK506-binding proteins (FKBPs). These proteins display a peptidyl-prolyl rotamase function that is believed to catalyze protein folding and they are well-validated anti-proliferative drug targets in certain pathogenic microorganisms, and their functions have been characterized in parasitic protozoa. However, much less is known in helminths and trials with rapalogs on cestoda have not yet been reported. Due to a growing need for new treatment options for human cystic echinococcosis, the in vitro efficacy of rapalogs in Echinococcus granulosus was investigated. We determined the effect of ramapycin, FK506 and everolimus against this cestode, demonstrating their protoscolicidal ability. Also, we observed synergic scolicidal actions during combined therapy with rapalogs plus cyclosporine A, proposing dual administration of drugs to improve pharmacological effects in vivo. We have identified an E. granulosus (Eg)-fkb1 gene that encodes Eg-FKBP, an archetypal protein of the FKBP family, which includes all residues implicated in the binding of pharmacological ligands, in the enzymatic activity and in interactions with possible target proteins. Levels of Eg-fkb1 mRNA are over-expressed by acid but not rapalog treatment. We also described the presence of receptor-operated calcium channels in the larval stage, suggesting that exogenous ligands may dissociate the interaction of Eg-FKBP from these intracellular channels, enhancing the activity of the Ca(2+) release and interfering with their normal regulatory functions. As rapamycin sensitivity is the major criterion used to detect targets of rapamycin kinase, we identified and analyzed in silico critical residues of putative homologs in the Echinococcus genome. These preliminary results will allow us to continue subsequent studies that could reveal the precise intracellular functions of Eg-FKBP, providing greater knowledge for further identification of downstream target proteins, a promising target for chemotherapy of cystic echinococcosis.
FK506（他克莫司）和聚酮大环内酯类如雷帕霉素及其衍生物与 FK506 结合蛋白（FKBP）结合。这些蛋白质显示出肽基脯氨酰旋转酶的功能，据信可催化蛋白质折叠，它们是某些致病微生物中经过充分验证的抗增殖药物靶点，其功能已在寄生原生动物中得到了表征。然而，在蠕虫中知之甚少，并且尚未报道在带绦虫上使用雷帕霉素类似物的试验。由于对人类包虫病的新治疗选择的需求不断增长，因此研究了雷帕霉素类似物在细粒棘球绦虫中的体外功效。我们确定了雷帕霉素、FK506 和依维莫司对这种带绦虫的作用，证明了它们的原头节杀幼虫能力。此外，我们在雷帕霉素类似物加环孢菌素 A 联合治疗期间观察到协同杀幼虫作用，提出双重给药以改善体内药物的药理作用。我们已经鉴定出一个细粒棘球绦虫（Eg）-fkb1 基因，该基因编码 Eg-FKBP，这是 FKBP 家族的典型蛋白质，其中包含与药理学配体结合、酶活性以及与可能的靶蛋白相互作用有关的所有残基。Eg-fkb1 mRNA 的水平通过酸而非雷帕霉素类似物处理而过度表达。我们还描述了幼虫阶段存在受体操作的钙通道，这表明外源性配体可能使 Eg-FKBP 与这些细胞内通道的相互作用解离，从而增强 Ca2+释放的活性并干扰其正常的调节功能。由于雷帕霉素敏感性是检测雷帕霉素激酶靶标的主要标准，因此我们在棘球蚴基因组中鉴定并分析了潜在同源物的计算机分析关键残基。这些初步结果将使我们能够继续进行后续研究，这些研究可能揭示 Eg-FKBP 的精确细胞内功能，为进一步鉴定下游靶蛋白提供更多知识，这是囊性包虫病化学疗法的有前途的靶标。
