THE FUNCTIONAL GENOMICS OF BYSTANDER RESPONSES

描述（由申请人提供）：虽然细胞电离辐射的传统研究 尽管细胞的辐射反应集中在能量在细胞核中的直接沉积上，但现在认识到细胞也对核外辐射损伤作出反应，甚至通过旁观者效应对细胞外辐射损伤作出反应。然而，在不同的细胞室调节损伤的反应的差异信号转导途径还没有得到很好的阐明。该项目旨在利用微阵列分析和功能基因组学的力量，结合单细胞/单粒子微束辐照器，以深入了解细胞间和细胞间对辐射损伤的反应的信号传导机制。原代细胞和3-D组织模型的细胞质和旁观者照射诱导的基因表达谱的分析应导致识别的分子靶点的辐射反应的修改。这些将被验证 通过使用表达载体、siRNA或化学抑制剂。细胞外修饰 在不是所有细胞都受到直接照射的低剂量暴露的情况下，以及在有限的区域较高剂量暴露的情况下，例如在放射疗法中给予的那些，其中已知晚期效应发生在治疗区域之外，发信号可能特别有吸引力。基因表达谱将用于推进我们对花生四烯酸级联反应下游效应基因的理解，这些基因可能在介导旁观者反应中起重要作用。一系列四个相互关联的具体目标将解决两个主要的可检验的假设。最终，了解细胞内和细胞间辐射损伤的分子基础将促进我们对辐射反应机制和旁观者效应的认识。

DESCRIPTION (provided by applicant): While traditional studies of cellular ionizing radiation responses have focused on the direct deposition of energy in the nucleus, it is now recognized that cells also respond to extra-nuclear radiation damage, and even to extra-cellular radiation damage via the bystander effect. However, the differential signal transduction pathways regulating the responses to damage in different cellular compartments have not been well elucidated. This project seeks to harness the power of microarray profiling and functional genomics in conjunction with the single-cell / singleparticle microbeam irradiator in order to gain insight into the mechanisms of signaling between cellular compartments and between cells in response to radiation damage. Analysis of gene expression profiles induced by cytoplasmic and bystander irradiation of primary cells and a 3-D tissue model should lead to identification of molecular targets for modification of the radiation response. These will then be validated through the use of expression vectors, siRNA or chemical inhibitors. Modification of extracellular signaling may be especially attractive, both in cases of low dose exposures where not all cells suffer direct irradiation, and in limited field higher dose exposures, such as those given in radiotherapy, where late effects are known to occur outside the treatment field. Gene expression profiling will be used to advance our understanding of down-stream effector genes of the arachidonic acid cascade that may be important in mediating the bystander response. A series of four inter-related specific aims will address two main testable hypotheses. Ultimately, understanding the molecular basis for the communication of radiation damage within and among cells will advance our knowledge of the mechanisms of radiation response and the bystander effect.