Trypansoma cruzi-induced host cell signaling responses

描述(由申请人提供)：动体原生动物寄生虫克氏锥虫在人类中引起恰加斯病，这是一种慢性和衰弱的疾病，影响着拉丁美洲的数百万人。由于克氏毛滴虫的脊椎期是专性的细胞内寄生虫，阐明感染所需的宿主与病原体的相互作用对于了解克氏毛滴虫的致病机制至关重要。我们的初步发现强调了寄生性液泡作为克氏锥虫细胞内生命周期的过渡点，将调节液泡形成和成熟的早期信号和细胞变化与寄生虫从液泡中出现时引起的基因表达的下游变化联系起来。我们将在分子和细胞水平上对克氏锥虫液泡的形成、成熟和破坏过程进行详细的分析。通过对IFNb基因表达的诱导，我们将确定触发这种反应所需的宿主细胞信号转导途径。最后，我们将使用DNA微阵列分析来进一步表征宿主对克鲁兹旋毛虫的转录反应，具体目标是确定哪些变化是对克鲁兹旋毛虫感染的初级反应，而不是由感染克鲁兹旋毛虫的细胞释放的可溶性因子引发的大多数二级、第三级反应。对于这种病原体在细胞内生长和存活所需的分子和细胞事件，人们知之甚少。我们提出的检查这些早期事件的多方面方法将提供目前我们对克氏锥虫感染过程缺乏的分子细节。正是对这些基本过程的理解将指导我们有效预防和控制恰加斯病的努力。

DESCRIPTION (provided by the applicant): The kinetoplastid protozoan parasite Trypanosoma cruzi causes Chagas' disease in humans, a chronic and debilitating condition affecting several million individuals in Latin America. Since the vertebrate stages of T. cruzi are obligate intracellular parasites, elucidation of host-pathogen interactions required for establishment of infection is crucial to understanding mechanisms of T. cruzi pathogenesis. Our preliminary findings highlight the parasitophorous vacuole as a transitional point the T. cruzi intracellular life cycle, linking early signaling and cellular changes regulating formation and maturation of the vacuole to downstream changes in gene expression evoked upon emergence of parasites from the vacuole. We will carry out a detailed analysis of the process of T. cruzi vacuole formation, maturation and disruption the molecular and cellular levels. Using the induction of IFNb gene expression as a sensitive reporter for host cell transcriptional responses elicited by vacuole egress by T. cruzi, we will define the host cell signaling pathways required to trigger this response. Finally, we will employ DNA microarray analysis to further characterize host transcriptional responses to T. cruzi with the specific goal of determining which changes are elicited as a primary response to T. cruzi infection versus the majority of secondary, tertiary, responses elicited by soluble factors released from T. cruzi-infected cells. Little is known regarding the molecular and cellular events required to shape a permissive host cell environment for intracellular growth and survival of this pathogen. The multi-faceted approach we propose to examine these early events will provide molecular detail currently lacking in our understanding of the T. cruzi infective process. It is the understanding of these basic processes that will guide our efforts toward effective prevention and control of Chagas' disease.