Dissecting the Signaling Network for Ah Receptor-mediated B-cell Toxicity

一项对超级基金地点人类暴露途径的综合评估显示，污染物 作为AHR激动剂对周围居民构成重大风险，免疫效果是 毒物学研究最少的终点之一。这个项目的主要目标有两个：(1) 解剖参与抑制B细胞活化和IgM分泌的基因表达级联反应 接触AHR激动剂；(2)结合关于基因表达级联的信息与全面的 概述蛋白质相互作用和重点分子实验，以创建一个完整的系统级模型，研究AhR在B细胞中的作用 差异化信令网络。我们假设B细胞分化网络中的多个节点 是由AHR监管的。通过解剖基因表达内部的相互关系，它们一起级联在一起 有了一个全面的蛋白质相互作用图，我们将能够对剂量-反应进行机械建模 行为表现为Ahr B细胞免疫毒性。这一假设将使用一种独特的组合进行验证 分析暴露于AHR后转录级联的基因组和计算工具 激动剂，并推断细胞信号网络的相应结构，用于计算建模。 这项建议的具体目的是：(1)确定B细胞基因表达中依赖于AhR的变化 脂多糖激活和接触原型AhR激动剂TCDD后的级联反应；(2)表征 AHR激活对B细胞分化过程中基因表达原发改变的直接顺式作用 级联；(3)描述初级基因表达事件与次级和次级基因表达事件之间的关系 AhR介导的B细胞分化改变的第三级基因表达变化；以及(4)联合 关于AhR调控的B细胞基因表达级联的信息和蛋白质的综合研究 相互作用和有重点的分子实验，以创建集成的系统级计算 AHR和B细胞分化信号网络模型。通过这些具体目标，我们将制定一项 系统级的方法将提供对细胞信号的定量和机械的理解 参与AHR激动剂抑制B细胞分化的网络。具体地说，基因组工具将 提供有关B细胞基因转录反应和功能关系的快照 分化途径，而计算模型将用于提供定量的生物学 结构连接到信令网络。系统方法的发展对 通过提供一种机制来系统地调查环境健康社区 包含在改变的基因的列表中的因果关系以及 参与在环境相关剂量下产生毒理效应的信号网络。

A comprehensive evaluation of human exposure pathways at Superfund sites reveals that contaminants functioning as Ahr agonists present a significant risk to surrounding residents and immunological effects are one of the least studied toxciological end points. The primary objectives of this project are two-fold: (1) dissect the gene expression cascade involved in suppression of B-cell activation and IgM secretion following exposure to Ahr agonists; (2) combine information on the gene expression cascade with a comprehensive survey of protein interactions and focused molecular experimentation to create an integrated, systems-level model of the role of Ahr in the B-cell differentiation signaling network. We hypothesize that multiple nodes in the B-cell differentiation network are regulated by the Ahr. By dissecting the interrelationships within the gene expression cascade together with a comprehensive protein interaction map, we will be able to mechanistically model the dose-response behavior for Ahr B-cell immunotoxicity. This hypothesis will be tested using a unique combination of genomic and computational tools that dissect the transcriptional cascades following exposure to an Ahr agonist and infer the corresponding structure of the cellular signaling network for computational modeling. The specific aims of this proposal are: (1) identify Ahr-dependent alterations in the B-cell gene expression cascade following activation with LPS and exposure to the prototype Ahr agonist TCDD; (2) characterize the direct, cis-acting effects of Ahr activation on primary changes in gene expression in the B-cell differentiation cascade; (3) delineate the interrelationships between primary gene expression events and secondary and tertiary gene expression changes for Ahr-mediated alterations in B-cell differentiation; and (4) combine information on the Ahr-regulated B-cell gene expression cascade with a comprehensive survey of protein interactions and focused molecular experimentation to create an integrated, systems-level computational model of the Ahr and B-cell differentiation signaling network. Through these specific aims, we will develop a systems-level approach will provide a quantitative and mechanistic understanding of the cellular signaling network involved in the suppression of B-cell differentiation by Ahr agonists. Specifically, genomic tools will provide snapshots into transcriptional responses and functional relationships between genes in the B-cell differentiation pathway, while computational modeling will be used to provide a quantitative biological structure to the signaling network. The development of a systems approach is significant for the environmental health community as a whole by providing a mechanism to systematically investigate the cause-and-effect relationships contained within the lists of altered genes and the underlying logic of the signaling network involved in producing the toxicological effect at environmentally relevant doses.