Caspase activation during PAH induced apoptosis

这项建议的总体目标是确定在PAH介导的细胞凋亡过程中在Preb细胞中发生的分子事件。阐明这些化合物的作用机制将增加我们对它们如何发挥免疫毒性的理解。这一建议的中心假设是多环芳烃(PAHs)通过caspase-8以I型方式诱导淋巴细胞凋亡，从而导致Preb细胞死亡。这一假设得到了我的初步数据的支持，这些数据表明，DMBA处理Preb细胞后，caspase-8和caspase-3激活，而caspase-9的激活程度较小。进一步的证据表明，可溶性FasL能够诱导caspase-8和Preb细胞的凋亡。在拟议的项目中，我将通过以下方式进一步扩展这些发现：1)鉴定在Preb细胞/基质细胞共培养系统中caspase激活和辅助蛋白诱导的特定模式；2)通过用DMBA治疗GLD和LPR基因敲除小鼠，确定Fas/FasL通路是否对于体内的骨髓毒性是必需的；3)利用前两个目标建立的体内和体外系统，确定多环芳烃的免疫毒性和caspase激活之间的关系。

The overall goal of this proposal is to determine the molecular events that take place in preB cells during PAH mediated apoptosis. Delineating the mechanism of action of these compounds will increase our understanding of how they exert their immunotoxicity. The central hypothesis of this proposal is that polycyclic aromatic hydrocarbons (PAHs) cause death of preB cells by inducing apoptosis in lymphocytes via caspase-8 in a Type I manner. This hypothesis is supported by my preliminary data, which show that treatment of preB cells with DMBA activates caspase-8 and caspase-3, and to a lesser extent caspase-9. Further evidence is provided that soluble FasL is able to induce caspase-8 and apoptosis in preB cells. In the proposed project I will extend these findings further by: 1) characterizing the specific pattern of caspase activation and accessory protein induction in the preB cell/stromal cell co-culture system; 2) determine if the Fas/FasL pathway is necessary for in vivo bone marrow toxicity, by treating gld and lpr knockout mice with DMBA; 3) define the relationship between immunotoxicity of the PAHs and caspase activating, using other members of the PAH family in the in vivo and in vitro systems developed in the first two aims.