Butadiene-Induced P53-Mediated Apoptotic Signaling

丁二烯(BD)是一种高产量的化学品，目前被列为有害空气污染物。 这种环境化学物质是一种已知的诱变剂和人类致癌物，具有广泛的 造血，生殖和神经毒性，包括骨髓衰竭，卵巢， 脾和胸腺萎缩。因此，我们的长期目标是阐明细胞和分子机制。 对丁二烯的毒性负责。我们实验室最近的研究表明， 丁二烯最有效的活性代谢物二环氧丁烷(DEB)诱导人P53调控的细胞凋亡 淋巴细胞。P53在DEB诱导的细胞凋亡中的作用及其信号转导机制如下 目前尚不清楚。尽管抑癌蛋白P53是一种多功能转录因子， 介导各种形式的应激反应中的细胞凋亡，P53信号转导和 作用尚不清楚，已知的是细胞类型和毒物依赖。这项提议的目标是， 因此，确定DEB诱导的P53介导的细胞凋亡信号通路，并确定 P53调控DEB诱导的人淋巴细胞凋亡的分子机制。本研究 将检验核心假设，即DEB诱导的DNA损伤和活性氧物种的产生将 激活包括p300、DNA-PK和ATM/ATR在内的多个信号通路来调节P53的丰度 和通过翻译后修饰的凋亡活性，导致关键的特异性p53的控制 介导DEB诱导的P53的反应基因和产物调节人淋巴母细胞的凋亡。 我们期望通过执行以下四个步骤来验证我们的假设并实现此应用程序的目标 明确的目标。(1)。识别作为凋亡信号激活的DEB诱导的初始细胞损伤 P53在DEB诱导的人淋巴母细胞凋亡中的作用。(2)识别上行信令 DEB激活P53途径介导DEB诱导的人淋巴母细胞凋亡。 (3)确定DEB如何激活P53，以介导DEB诱导的人淋巴细胞凋亡。(4) 确定P53如何调节二环氧丁烷诱导的人类细胞凋亡(P53下游) 淋巴母细胞。在这些研究完成后，我们的期望是DEB诱导的机制 我们将对细胞凋亡进行定义，并更好地了解P53在这一过程中的作用。这一知识将会 对丁二烯风险评估以及之后更好的干预手段产生重要的垂直影响 丁二烯暴露。本研究因使用量大、偶然性强，与公众健康密切相关 位于墨西哥湾沿岸的石化工业区排放大量丁二烯。

Butadiene (BD) is a high production volume chemical that is currently regulated as a hazardous air pollutant. This environmental chemical is a known mutagen and human carcinogen, and possesses a wide range of hematopoietic, reproductive, and neurological toxicity, which includes bone marrow depletion, ovarian, spleen and thymus atrophy. Thus, our long-term goal is to elucidate the cellular and molecular mechanisms responsible for the toxicity of butadiene. Recent studies from our laboratory have demonstrated that butadiene's most potent active metabolite, diepoxybutane (DEB), induces p53 regulated apoptosis in human lymphocytes. The mechanisms of p53 action and p53 mediated signaling in DEB-induced apoptosis are currently unknown. Although the tumor suppressor p53 protein is a multifunctional transcription factor that mediates apoptosis in response to various forms of stress, the molecular mechanism of p53 signaling and action remain unclear, and is known to be cell type and toxicant dependent. The objective of this proposal, therefore, is to identify the DEB-induced p53-mediated apoptotic signaling pathways and determine the molecular mechanisms by which p53 regulates DEB-induced apoptosis in human lymphocytes. This study will test the central hypothesis that DEB-induced DNA damage and reactive oxygen species generation will trigger multiple signaling pathways that include p300, DNA-PK and ATM/ATR to regulate p53 abundance and apoptotic activity through post-translational modifications, resulting in the control of key specific p53 responsive genes and products that mediate DEB-induced p53 regulated apoptosis in human lymphoblasts. We expect to test our hypothesis and achieve the objective of this application by pursuing the following four specific aims. (1). Identify the initial DEB-induced cellular lesion serving as the apoptotic signal activating p53 to mediate apoptosis in human lymphoblasts exposed to DEB. (2) Identify the upstream signaling pathways induced by DEB to activate p53 into mediating DEB-induced apoptosis in human lymphoblasts. (3) Determine how p53 is activated by DEB to mediate DEB-induced apoptosis in human lymphocytes. (4) Determine how p53 regulates diepoxybutane-induced apoptosis (downstream of p53) in human lymphoblasts. At the completion of these studies, our expectation is that the mechanism of DEB-induced apoptosis will be defined and the role of p53 in this process will be better understood. This knowledge will have an important vertical impact on butadiene risk assessment as well as better means of intervention after butadiene exposure. This research is of relevance to public health due to the heavy use and accidental emissions of large volume of butadiene in petrochemical industrial areas located around the gulf coast.