Department of Immunology, Institute for Biomedical Research, Universidad Nacional Autónoma de México, Ciudad de México, México.
Department of Parasitology, School of Medicine, Universidad Nacional Autónoma de México, Ciudad de México, México.
Biosci Rep. 2018 Jul 6;38(4). doi: 10.1042/BSR20180636. Print 2018 Aug 31.
During the study of host-parasite relationships in taeniid parasite diseases, including cysticercosis and hydatidosis, reports have described the presence of host proteins in the cyst fluid and tissue of metacestodes. However, the fate or role of host elements inside the parasite remains barely explored. After the publication of genomes of four cestode species, it became clear that these organisms possess a limited biosynthetic capability. The initial goal of the present study was to determine if uptaken host proteins could be a source of essential amino acids for cysticerci. To track the utilization of uptaken proteins, we added metabolically labeled IgG-H and GFP-H to the culture medium of cysticerci. Incorporation of labeled amino acid was evaluated by fluorography in cysticerci extracts. Our results showed that the use of uptaken proteins by cysticerci as a source of amino acids appeared negligible. Exploring alternative fates for the host proteins, proteomic analysis of the protein matrix in calcareous corpuscles was carried out. Since does not contain calcareous corpuscles, proteomic analyses were performed in corpuscles of cysticerci. Our results demonstrated that host proteins represented approximately 70% of protein content in the calcareous corpuscles. The presence of the two major uptaken host proteins, namely albumin and IgG, was also demonstrated by Western blot in the matrix of corpuscles. Our findings strongly suggested that the uptake and disposal of host proteins involve calcareous corpuscles, expanding the physiological role of these mineral concretions to a far more important level than previously proposed.
在研究包虫病等带绦虫寄生虫病的宿主-寄生虫关系时，有报道称在囊液和囊蚴组织中存在宿主蛋白。然而，寄生虫内宿主成分的命运或作用仍未得到充分探索。在发表了四种绦虫物种的基因组后，人们清楚地认识到这些生物体具有有限的生物合成能力。本研究的最初目标是确定被摄取的宿主蛋白是否可以成为囊尾蚴必需氨基酸的来源。为了追踪被摄取蛋白的利用情况，我们将代谢标记的 IgG-H 和 GFP-H 添加到囊尾蚴的培养基中。通过对囊尾蚴提取物进行荧光成像来评估标记氨基酸的掺入情况。我们的结果表明，囊尾蚴利用被摄取的蛋白作为氨基酸来源的情况似乎可以忽略不计。为了探索宿主蛋白的替代命运，我们对钙颗粒蛋白基质进行了蛋白质组学分析。由于 不含有钙颗粒，因此在 囊尾蚴的钙颗粒中进行了蛋白质组学分析。我们的结果表明，宿主蛋白约占钙颗粒蛋白含量的 70%。Western blot 分析也证实了两种主要被摄取的宿主蛋白，即白蛋白和 IgG，存在于钙颗粒的基质中。我们的研究结果强烈表明，宿主蛋白的摄取和处理涉及钙颗粒，这将这些矿物质凝结物的生理作用扩展到了比之前所提出的更为重要的水平。
