Transplantation: Alloimmune Networks

描述（由申请人提供）：我们的目标是了解在移植物排斥反应中调节免疫反应的分子相互作用。多项研究表明，移植物排斥反应是复杂的、多基因的，但人们对其知之甚少。为了研究调节排斥反应的分子相互作用网络，在本提案中，我们将系统生物学分析应用于一个具有良好特征的移植模型。使用小鼠心脏移植模型，我们的初步数据表明，移植物缺乏产生IL-6，移植物存活率约为三倍。移植物产生的IL6克服调节性T细胞的抑制，促进CD4和CD8 T效应细胞的激活。因此，移植物产生的IL6作为一个分子触发器，调节移植后免疫反应的多个组成部分。我们实验室设计的研究这一复杂过程的实验方法有两个互补的组成部分。首先，我们将在一个已建立的实体器官移植模型（小鼠心脏移植）中研究一个重要的观察结果（移植物产生的IL-6缺乏导致移植物存活时间延长）。其次，我们将应用最先进的微阵列技术、生物信息学、生物统计学和系统生物学来构建和分析调节排斥反应的调控相互作用和信号转导途径的全局分子模型。我们的初步数据和最近的出版物表明，我们可以成功地进行这些研究。因此，我们建议应用系统生物学方法，这是该应用的支柱，是适当的，及时的，并与传统方法协同，以增加对排斥反应的理解。我们的总体生物学假设是移植物组织损伤诱导il - 6分泌，il - 6作为系统性危险信号激活外周免疫细胞。我们将采用还原论和系统方法来解决这些问题。在Aim I中，我们将确定移植后由移植物产生的IL-6调节的候选信号转导途径。在Aim II中，我们将使用子网络和信号转导途径预测RNAi敲除实验靶点的生物学反应。我们预计，我们基于系统的方法将为移植后免疫反应的调节提供新的见解，并有可能确定新的治疗策略来防止移植器官的排斥反应。

DESCRIPTION (provided by applicant): Our goal is to understand the molecular interactions that regulate the immune response during graft rejection. Multiple studies indicate that graft rejection is complex, polygenic and poorly understood. To investigate the network of molecular interactions that regulate rejection, in this proposal we apply a systems biology analysis to a well-characterized model of transplantation. Using a murine model of heart transplantation, our preliminary data demonstrate that a deficiency of graft produced IL-6 approximately triples graft survival. Graft produced IL6 overcomes suppression by regulatory T cells, and promotes the activation of CD4 and CD8 T effector cells. Thus, graft-produced IL6 functions as a molecular trigger that modulates multiple components of the immune response following transplantation. The experimental approach designed by our laboratory to investigate this complex process has 2 complementary components. First, we will investigate an important observation (prolongation of graft survival due to a deficiency of graft-produced IL-6) in an established solid organ transplant model (murine cardiac transplantation). Second, we will apply state of the art microarray technology, bioinformatics, biostatistics, and systems biology to construct and analyze global molecular models of the regulatory interactions and signal transduction pathways modulating rejection. Our preliminary data and recent publications establish that we can successfully perform these studies. Thus, we propose that applying a systems biology approach, which is the backbone of this application, is appropriate, timely, and synergistic with conventional approaches, to increase understanding of the rejection response. Our overall biological hypothesis is that injury to graft tissue induces IL6 secretion, which functions as a systemic danger signal to activate peripheral immune cells. We will employ both reductionist and systems approaches to address these questions. In Aim I, we will identify candidate signal transduction pathways modulated by graft-produced IL-6 following transplantation. In Aim II, we will predict biological responses for targets of knockdown experiments with RNAi using subnetworks and signal transduction pathways. We anticipate that our systems based approach will provide novel insights into the regulation of immune responses following transplantation and has the potential to identify new therapeutic strategies to prevent the rejection of grafted organs. PUBLIC HEALTH RELEVANCE: We will investigate the immune mechanisms that may be important in determining whether a transplant is accepted or rejected by the patient. We are focusing on interleukin-6 (IL- 6), a cytokine with diverse functions. We have found that IL-6 produced by the donor graft accelerates rejection of the graft. In addition to IL-6, we will analyze immune genes and pathways using microarrays and construct biological interaction networks using systems biology methods to investigate the signals that promote rejection.