Identification and function of mechanosensitive channels in Trypanosoma cruzi

摘要 查加斯病是一种人畜共患的热带疾病，由原生动物寄生虫克氏锥虫引起。 它在拉丁美洲流行，是世界上充血性心力衰竭的主要原因之一。历史上 与农村地区的贫困有关，病媒的移民和迁移正在改变流行病学， 这种疾病的发病率，美国的病例数量大幅增加就是证明。治疗是 仅限于硝呋替莫和苄硝哒唑，这两种药物都相对有毒，疗效有限， 经FDA批准。我们的实验室一直致力于寻找合理的化学治疗方法 可以选择性地针对寄生虫而不损害人体细胞。 研究寄生虫的感知、适应和生存机制对防治寄生虫病具有重要意义。 确定选择性药物靶点，可以导致消除寄生虫而不影响宿主。 在向不同生命阶段转化的过程中，T.克鲁兹发现， 它必须适应这些条件才能生存。机械敏感通道是阳离子通道，能够 检测膜张力的变化，通常由脂质双层的拉伸激活。他们 被认为是多种细胞和生物体中渗透压变化的主要传感器， 信号传导通路驱动着神经调节。虽然T. cruzi在 低渗和高渗条件下，分子的身份检测变化和引发适应性 寄生虫的反应仍然未知。先前的计算机模拟研究表明存在几种假定的 T.克鲁兹我们已经确定了一个通道的存在和表达， 小电导机械敏感通道（TcMcS）共享的结构特征。TcMcS堵塞， 遗传学和药理学方法影响细胞的免疫调节能力。我们建议 与细菌通道具有同源性的机械敏感通道在传感和 T. cruzi，确定宿主细胞入侵的成功， 寄生虫的生存分析了T. Cruzi机械敏感通道表达谱和定位， 辅以电生理学研究将揭示激活机制， 调节这些蛋白质。体内表达水平的遗传操作和表型分析 将证明TcMcS通道在寄生虫中的生理作用，并将有助于建立其潜力 作为治疗靶点。

Abstract Chagas disease is a zoonotic tropical pathology, caused by the protozoan parasite Trypanosoma cruzi. Endemic in Latin America, it is one of the leading causes of congestive heart failure in the world. Historically associated with poverty in rural areas, immigration and relocation of the vectors are changing the epidemiology of the disease, as evidenced by a substantial increase in the number of cases in the US. Treatment is restricted to nifurtimox and benznidazole, both of which are relatively toxic, have limited efficacy and are not approved by the FDA. Our laboratory has been working on the rational search for chemotherapeutic treatments for Chagas disease that can selectively target the parasite without compromising human cells. The study of the mechanisms of sensing, adaptation and survival of the parasite is important for the identification of selective drug targets that can lead to the elimination of the parasite without affecting the host. During the transformation into different life stages, T. cruzi finds extreme fluctuations in environmental conditions to which it must adapt in order to survive. Mechanosensitive channels are cation channels able to detect changes in the tension of the membranes and usually are activated by stretch of the lipid bilayer. They are considered the primary sensors of osmotic changes in a multiplicity of cells and organisms, triggering signaling pathways that drive osmoregulation. Although T. cruzi has a robust compensatory response under hyposmotic and hyperosmotic conditions, the identity of the molecules detecting changes and eliciting adaptive responses in the parasites is still unknown. Previous in silico studies suggest the presence of several putative mechanosensitive channels in T. cruzi. We have identified the presence and expression of a channel with structural features shared by small conductance mechanosensitive channels (TcMcS). TcMcS blockage by genetic and pharmacological methods affects the osmoregulatory capacity of the cells. We propose that mechanosensitive channels with homology to bacterial channels play an important role in sensing and adaptation to environmental conditions in T. cruzi, determining the success of the host cell invasion and survival of the parasite. Analysis of T. cruzi mechanosensitive channels expression profiles and localization, complemented with electrophysiological studies will shed light about the mechanism of activation and modulation of these proteins. Genetic manipulation of the level of expression and phenotypic analysis in vivo will demonstrate the physiological role of TcMcS channels in the parasite and will help establish their potential as therapeutic targets.