MECHANISM OF BYSTANDER MUTAGENESIS

旁观者诱变机制

• 批准号: 8281639
• 负责人: Tom K. Hei
• 金额: $ 36.8万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-01 至 2015-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8281639
• 关键词: Abdomen; Abdominal Cavity; Address; Animals; Apoptosis; Area; Bystander Effect; Cell Culture Techniques; Cell Nucleus; Cells; Chest; Communication; Connexins; Control Animal; Cytoplasm; DNA; Data; Diagnostic radiologic examination; Dinoprostone; Dose; Embryo; Fibroblasts; Gap Junctions; Gene Expression; Genes; Genetic; Genomic Instability; Goals; Health; High Pressure Liquid Chromatography; Human; In Vitro; Incidence; Instruction; Ionizing radiation; Low Dose Radiation; Mammalian Cell; Mammary Gland Parenchyma; Mediating; Mediator of activation protein; Mitochondria; Mitochondrial DNA; Modeling; Mus; Mutagenesis; Mutate; Mutation; NF-kappa B; Nuclear; Oxidative Stress Induction; Patients; Play; Point Mutation; Population; Process; Proteins; Radiation; Radiation therapy; Reverse Transcriptase Polymerase Chain Reaction; Risk Assessment; Roentgen Rays; Role; Sampling; Series; Signal Pathway; Signaling Molecule; Signaling Pathway Gene; Signaling Protein; Small Interfering RNA; Staging; Structure of parenchyma of lung; Time; Tissue Stains; Tissues; Transgenic Mice; Universities; cancer risk; cellular targeting; cyclooxygenase 1; cyclooxygenase 2; human NOS2A protein; human tissue; in vivo; irradiation; micronucleus; mitochondrial DNA mutation; novel; oxidative DNA damage; programs; response; theories

PROJECT SUMMARY (See instructions): Radiation induced bystander effects have been demonstrated with a variety of endpoints using mammalian cell cultures as well as 3D human tissues. However, neither the mechanism nor the relevance of the bystander response to human health is clear. While gap junction communication and presence of soluble mediator(s) are known to play an important role in the bystander response, the precise signaling molecules have yet to be identified. The overall goals of this project are to define the incidence and mechanism of radiation-induced bystander mutagenic response in vivo (non-targeted response); to clarify the role of cyclooxygenase-2(COX-2) signaling pathways in the process; and to examine the incidence of genomic instability in bystander tissues in wild type and in genetic susceptible animals. The central testable hypothesis is that COX-2 mediates radiation induced bystander mutagenesis in vivo and that the bystander cells are genomically unstable in ATM homozygously mutated animals. A series of five inter-related specific aims are proposed to address these goals. The novel gpt delta ttansgenic mice and embryo fibroblasts from these animals will be used to conelate the findings under both in vitro and in vivo conditions. A small 1 cm by 1 cm zone in the lower abdominal area will be inadiated with graded doses of X-rays and the expression of COX-2 levels as well as incidence and types of Spi (deletions) and gpt (point mutations) mutations will be examined in the non-targeted lung and breast tissues. Bystander response as a result of nuclei and cytoplasmic targeting in MEF cells from wild type and COX-2knock out mice will be conducted with a microbeam to delineate specific gene signaling pathways. To further define genomic instability in bystander tissues, incidence of gpt and Spi mutations will be examined over a period of several weeks post-irradiation in wild type as well as y47Mknock out mice. Extensive program interaction with Projects 1 and 3 are planned in that the role of Rad9 (Project 1) and the connexin protein (TCTP, Project 3) in modulating COX-2 function will be examined. Radiation induced bystander effects represent a paradigm shift in our understanding of the basic radiobiological principle and target theory of ionizing radiation. A better understanding of the mechanism of the bystander effect is important for an accurate assessment of cancer risk associated with low dose radiation exposure.

项目摘要（参见说明）： 使用哺乳动物细胞培养物以及 3D 人体组织，已通过多种终点证明了辐射引起的旁观者效应。然而，旁观者反应与人类健康的机制和相关性尚不清楚。虽然已知间隙连接通讯和可溶性介质的存在在旁观者反应中发挥重要作用，但精确的信号分子尚未确定。该项目的总体目标是明确体内辐射引起的旁观者致突变反应（非靶向反应）的发生率和机制；阐明环氧合酶-2(COX-2)信号通路在此过程中的作用；并检查野生型和遗传易感动物的旁观者组织中基因组不稳定性的发生率。中心可检验的假设是COX-2介导体内辐射诱导的旁观者诱变，并且旁观者细胞在ATM纯合突变动物中基因组不稳定。为了实现这些目标，提出了一系列五个相互关联的具体目标。新型 gpt delta 转基因小鼠和来自这些动物的胚胎成纤维细胞将用于在体外和体内条件下关联研究结果。下腹部区域的 1 cm x 1 cm 小区域将接受分级剂量的 X 射线照射，COX-2 水平的表达以及 Spi（缺失）和 gpt（点突变）突变的发生率和类型将被检测。在非目标肺和乳腺组织中进行检查。野生型和 COX-2 敲除小鼠的 MEF 细胞中的细胞核和细胞质靶向导致的旁观者反应将用微束进行，以描绘特定的基因信号传导途径。为了进一步确定旁观者组织中的基因组不稳定性，将在野生型和 y47M 敲除小鼠中检查照射后几周内 gpt 和 Spi 突变的发生率。计划与项目 1 和 3 进行广泛的程序交互，以检查 Rad9（项目 1）和连接蛋白（TCTP，项目 3）在调节 COX-2 功能中的作用。辐射引起的旁观者效应代表了我们对电离辐射的基本放射生物学原理和目标理论的理解的范式转变。更好地理解旁观者效应的机制对于准确评估旁观者效应非常重要。 与低剂量辐射暴露相关的癌症风险。