Department of Biochemistry and Molecular Biology, George Washington University Medical Center, Washington, DC 20037, USA.
Hepatology. 2011 Jul;54(1):285-95. doi: 10.1002/hep.24354. Epub 2011 Jun 8.
Schistosoma haematobium is responsible for two-thirds of the world's 200 million to 400 million cases of human schistosomiasis. It is a group 1 carcinogen and a leading cause of bladder cancer that occurs after years of chronic inflammation, fibrosis, and hyperproliferation in the host liver. The coevolution of blood flukes of the genus Schistosoma and their human hosts is paradigmatic of long-term parasite development, survival, and maintenance in mammals. However, the contribution of host genes, especially those discrete from the immune system, necessary for parasite establishment and development remains poorly understood. This study investigated the role of metastasis-associated protein-1 gene (Mta1) product in the survival of S. haematobium and productive infection in the host. Using a Mta-1 null mouse model, here we provide genetic evidence to suggest that MTA1 expression positively influences survival and/or maturation of schistosomes in the host to patency, as we reproducibly recovered significantly fewer S. haematobium worms and eggs from Mta1-/- mice than wild-type mice. In addition, we found a distinct loss of cytokine interdependence and aberrant Th1 and Th2 cytokine responses in the Mta1-/- mice compared to age-matched wild-type mice. Thus, utilizing this Mta1-null mouse model, we identified a distinct contribution of the mammalian MTA1 in establishing a productive host-parasite interaction and thus revealed a host factor critical for the optimal survival of schistosomes and successful parasitism. Moreover, MTA1 appears to play a significant role in driving inflammatory responses to schistosome egg-induced hepatic granulomata reactions, and thus offers a survival cue for parasitism as well as an obligatory contribution of liver in schistosomiasis.
These findings raise the possibility to develop intervention strategies targeting MTA1 to reduce the global burden of schistosomiasis, inflammation, and neoplasia.
曼氏血吸虫导致全球 2 亿至 4 亿例人类血吸虫病中的三分之二。它是 1 类致癌物,也是导致膀胱癌的主要原因,这种膀胱癌是在宿主肝脏多年慢性炎症、纤维化和过度增生后发生的。曼氏血吸虫及其人类宿主的血液吸虫的共同进化是长期寄生虫在哺乳动物中发育、生存和维持的典范。然而,宿主基因,特别是与免疫系统不同的基因,对寄生虫的建立和发育所必需的贡献仍然知之甚少。本研究调查了转移相关蛋白 1 基因(Mta1)产物在曼氏血吸虫的生存和宿主中的有性感染中的作用。使用 Mta-1 缺失小鼠模型,我们提供了遗传证据表明,MTA1 表达阳性影响寄生虫在宿主中的存活和/或成熟到产卵期,因为我们从 Mta1-/- 小鼠中重复回收的曼氏血吸虫虫体和虫卵明显少于野生型小鼠。此外,我们发现 Mta1-/- 小鼠与年龄匹配的野生型小鼠相比,细胞因子相互依赖关系明显丧失,Th1 和 Th2 细胞因子反应异常。因此,利用这种 Mta1 缺失小鼠模型,我们确定了哺乳动物 MTA1 在建立有性宿主-寄生虫相互作用方面的独特贡献,从而揭示了宿主因子对血吸虫的最佳生存和成功寄生至关重要。此外,MTA1 似乎在驱动对血吸虫卵诱导的肝肉芽肿反应的炎症反应中发挥重要作用,因此为寄生虫提供了生存线索,也为血吸虫病中的肝脏提供了必要的贡献。
这些发现提出了一种可能性,即可以开发针对 MTA1 的干预策略,以减轻全球血吸虫病、炎症和肿瘤的负担。