Epigenic effects of environmental toxicants on cellular communication pathways

环境毒物对细胞通讯途径的表观影响

• 批准号: 6447061
• 负责人: JAMES Edward TROSKO
• 金额: $ 20.41万
• 依托单位: MICHIGAN STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-01 至 2002-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6447061
• 关键词: apoptosis; biological signal transduction; biotransformation; cell cell interaction; cell differentiation; cell line; cell proliferation; cytotoxicity; environmental toxicology; gap junctions; gene environment interaction; gene expression; halobiphenyl /halotriphenyl compound; hazardous substances; microarray technology; tissue /cell culture

Chemicals, such as PCB's, PBB's, TCDD, DDT, peroxisomes, proliferators, etc., which have been associated with birth defects, cancer, reproductive and neuro-behavioral dysfunctions in experimental animals, work by "epigenetic", not by genotoxic mechanisms [They all have been demonstrated to inhibit gap junctional intercellular communication (GJIC)]. The goal of the interdisciplinary project is to use an in vitro human neuron cell line with stem cell-like potential, to study the molecular (altered gene expression), biochemical (various mitogenetic/differentiation, signal transducing systems) and cellular (GFIC), cell proliferation, cell differentiation, apoptosis] mechanisms that might be affected by exposure to environmental toxicants prior to, or post, biological or chemical remediation processes. The proposal contains both an extension of our collaboration in the previous Superfund Program Project with Dr. Susan and Dr. W. Weber to assess the efficacy of their remediation techniques using our rat liver epithelial GJIC assay, as well as a new project to study the relationship of the modulation of GJIC in human neurons cells to chemically-induced signal transduction, to alterations in gene expression. The working hypothesis will be to determine if the blockage of GJIC by toxic chemicals is mediated by specific signal transduction mechanisms which might alter the expression of specific battery of genes which, in turn, could affect the cell's ability to regulate proliferation, cell differentiation or apoptosis. Three specific aims are proposed: Aim 1: To use known model toxicants with known structure/function relations to identify specific intracellular signaling associated with alterations of cell behavior; Aim : To study the signaling pathways, as in Aim 1, with the remediated mixtures to screen the efficacy of various remediation strategies; Aim 3: To test if the new DNA microarray technology can be used to identify altered gene expression associated with the altered GJIC and cellular endpoint studies of Aims 1 and 2. The significance is to provide validation of the inhibition of GJIC as a predictive endpoint of chemicals that can be toxic via their ability to trigger various signal transduction mechanisms that alter gene expression controlling either cell proliferation, cell differentiation, apoptosis or adaptive response of differentiated cells. In addition, using DNA microarray technology on a human in vitro system where many confounding factors can be controlled, identification of those genes associated with chemical-induced signal transduction systems and their associated biological effects might be easier and more relevant to the extrapolation of risk assessment in human beings, than the use of tissues from animal systems.

化学物质，如多氯联苯、多氯联苯、TCDD、DDT、过氧化物酶体、增殖体等，在实验动物中与出生缺陷、癌症、生殖和神经行为功能障碍有关，是通过“表观遗传”机制而不是通过基因毒性机制起作用的[它们都被证明能抑制间隙连接细胞间通讯（GJIC）]。该跨学科项目的目标是使用具有干细胞样潜能的体外人类神经元细胞系，研究在生物或化学修复过程之前或之后暴露于环境毒物可能影响的分子（改变的基因表达），生化（各种有丝分裂/分化，信号转导系统）和细胞（GFIC），细胞增殖，细胞分化，细胞凋亡)机制。该提案包含了我们在之前的超级基金项目中与Susan博士和W. Weber博士合作的扩展，以评估他们使用我们的大鼠肝上皮GJIC测定的修复技术的有效性，以及研究人类神经元细胞中GJIC调节与化学诱导的信号转导和基因表达改变之间的关系的新项目。工作假设将确定有毒化学物质对GJIC的阻断是否由特定的信号转导机制介导，这可能会改变特定基因的表达，进而影响细胞调节增殖、细胞分化或凋亡的能力。提出了三个具体目标：目标1：使用具有已知结构/功能关系的已知模型毒物来识别与细胞行为改变相关的特定细胞内信号；目的：与Aim 1一样，研究修复混合物的信号通路，以筛选各种修复策略的效果；目的3：测试新的DNA微阵列技术是否可用于鉴定与GJIC改变相关的基因表达改变以及目的1和2的细胞终点研究。这项研究的意义在于验证了GJIC的抑制可以作为化学物质的预测终点，这些化学物质可以通过触发各种信号转导机制来改变控制细胞增殖、细胞分化、细胞凋亡或分化细胞适应性反应的基因表达，从而具有毒性。此外，在人体体外系统中使用DNA微阵列技术可以控制许多混杂因素，识别与化学诱导的信号转导系统相关的基因及其相关的生物效应可能比使用动物系统的组织更容易，更与人类风险评估的外推相关。