Tsubokawa Daigo, Hatta Takeshi, Maeda Hiroki, Mikami Fusako, Goso Yukinobu, Nakamura Takeshi, Alim M Abdul, Tsuji Naotoshi
Department of Molecular and Cellular Parasitology, Kitasato University Graduate School of Medical Sciences, 1-15-1 Kitasato, Minami, Sagamihara, Kanagawa 252-0373, Japan; Department of Parasitology, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami, Sagamihara, Kanagawa 252-0374, Japan.
Department of Parasitology, Kitasato University School of Medicine, 1-15-1 Kitasato, Minami, Sagamihara, Kanagawa 252-0374, Japan; Department of Pathological and Preventive Veterinary Science, The United Graduate School of Veterinary Science, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan.
Acta Trop. 2017 Mar;167:99-107. doi: 10.1016/j.actatropica.2016.12.018. Epub 2016 Dec 22.
Sparganosis in humans caused by the plerocercoid larvae of Spirometra erinaceieuropaei is found worldwide, especially in Eastern Asia and the Far East. Previous studies have suggested that dissolution of plerocercoid body, plerocercoid invasion of host tissue, and migration are important processes for sparganosis progression. However, the mechanisms underlying these processes have yet to be determined. Here, we demonstrated the enzymatic property and involvement of a native 23kDa cysteine protease (Se23kCP), purified from plerocercoids, in sparganosis pathogenesis. Se23kCP is mature protease consisting of 216 amino acids and has a high sequence similarity with cathepsin L in various organisms. Se23kCP conjugated with N-glycans, which have a core fucose residue. Both cysteine and serine protease-specific activities were determined in Se23kCP and their optimal pHs were found to be different, indicating that Se23kCP has a wide range of substrate specificity. Se23kCP was secreted from tegumental vacuoles of the plerocercoid to host subcutaneous tissues and degraded human structural proteins, such as collagen and fibronectin. In addition, the plerocercoid body was lysed by Se23kCP, which facilitated larval invasion of host tissue. Our findings suggest that Se23kCP induces host tissue invasion and migration, and might be an essential molecule for sparganosis onset and progression.
由曼氏迭宫绦虫裂头蚴引起的人体裂头蚴病在全球范围内均有发现，尤其是在东亚和远东地区。先前的研究表明，裂头蚴虫体溶解、侵入宿主组织以及迁移是裂头蚴病进展的重要过程。然而，这些过程的潜在机制尚未确定。在此，我们展示了从裂头蚴中纯化出的一种天然23kDa半胱氨酸蛋白酶（Se23kCP）的酶学特性及其在裂头蚴病发病机制中的作用。Se23kCP是一种由216个氨基酸组成的成熟蛋白酶，与多种生物体中的组织蛋白酶L具有高度的序列相似性。Se23kCP与含有核心岩藻糖残基的N-聚糖结合。在Se23kCP中测定了半胱氨酸和丝氨酸蛋白酶的特异性活性，发现它们的最佳pH值不同，这表明Se23kCP具有广泛的底物特异性。Se23kCP从裂头蚴的皮层空泡分泌到宿主皮下组织，并降解人类结构蛋白，如胶原蛋白和纤连蛋白。此外，裂头蚴虫体被Se23kCP裂解，这促进了幼虫对宿主组织的侵入。我们的研究结果表明，Se23kCP诱导宿主组织的侵入和迁移，可能是裂头蚴病发生和进展的关键分子。
