Regulation of lymphocyte survival by NF-kB proteins

描述（由申请方提供）：淋巴细胞的发育和功能严重依赖于细胞凋亡对其存活的调节。过去几年进行的研究表明，TNF受体超家族的成员（例如，TNF受体1和Fas）在活化的成熟淋巴细胞中作为细胞凋亡的关键诱导剂起作用。然而，尚不清楚这些凋亡途径是否对调节发育中淋巴细胞的存活也很重要。本研究的目的是提供一个更好地了解参与发展淋巴细胞存活的促凋亡和抗凋亡机制。具体来说，我们将研究的作用，凋亡调节NF-κ B转录因子在调节发育中的B淋巴细胞的生存，使用基因敲除小鼠模型。1)我们在这里显示了一个损伤的淋巴细胞后过继转移ReIA-/-胎肝细胞到辐射淋巴细胞缺陷Rag 1-/-小鼠。在Re 1A和TNF受体1（TNFR 1）联合缺乏的情况下，受损的淋巴细胞生成在很大程度上得到了拯救，这表明Re 1A的关键功能可能是防止TNFR 1诱导的对发育中淋巴细胞的杀伤。在这里，我们将研究TNF诱导杀死RelA-/-发育中的B细胞的机制，包括caspase蛋白酶和活性氧（ROS）在TNF杀伤中的潜在参与。 为了了解RelA-/- B细胞对TNF敏感的机制，我们研究了潜在重要的抗凋亡基因的调节。我们发现，一个关键的抗凋亡基因Bcl-2的组成型表达在Re 1A-/- B细胞中显著降低。在这里，我们将进一步研究Re 1A在调节潜在重要的抗凋亡基因中的可能作用。使用逆转录病毒转导系统，我们将重新表达在RelA-/- B细胞中表现出受损表达的抗凋亡基因，以确定它们对TNF杀伤的作用。还将测定逆转录病毒转导的RelA-/-胎肝造血前体在Rag 1-/-小鼠中恢复淋巴细胞生成的能力。3） 我们还确定了成熟T细胞在调节发育中淋巴细胞存活方面的潜在重要作用。我们的研究结果表明，成熟的T细胞可以提供信号，这可以抵消TNFR 1的细胞毒性作用。在这里，我们将确定涉及的T细胞亚群，以及负责这种保护作用的T细胞衍生因子的性质。作为这种T细胞保护作用的介质特别感兴趣的是CD 4 OL和IL-3。在此，我们将确定CD 4 OL和IL-3在体外抑制TNF杀死Re 1 A-/-发育中的B细胞中的作用，以及在体内拯救淋巴细胞生成中的作用。这些研究也可以提供见解的发展战略，提高淋巴细胞生成的治疗环境。

DESCRIPTION (provided by applicant): The development and function of lymphocytes is critically dependent upon regulation of their survival by apoptosis. Studies 'carried-out over the last several years have shown that members of the TNF receptor superfamily (e.g., TNF receptor 1 and Fas) function as key inducers of apoptosis in activated mature lymphocytes. However, it is not known whether these apoptotic pathways 'are also important for regulating survival of developing lymphocytes. The goal of this investigation is to provide a better understanding of pro-apoptotic and anti-apoptotic mechanisms involved in developing lymphocyte survival. Specifically, we will study the role of the apoptosis-regulating NF-kB transcription factor in regulating survival of developing B-lymphocytes, using knock-out mouse models. 1) We show here an impairment of lymphopoiesis following adoptive transfer of ReIA-/- fetal liver cells into irradiated lymphocyte-deficient Rag1-/- mice. Impaired lymphocyte generation was largely rescued in the combined absence of Re1A and TNF receptor 1 (TNFR1), indicating a key function of Re1A may be to prevent TNFR1-induced killing of developing lymphocytes. Here we will investigate the mechanisms by which TNF induces killing of RelA-/- developing B cells, including the potential involvement of caspase proteases and reactive oxygen species (ROS) in TNF killing.2) To understand mechanisms responsible for susceptibility of RelA-/- B cells to TNF, we have studied regulation of potentially important anti-apoptotic genes. We have found that constitutive expression of one key anti-apoptotic gene, BcI-2, was 'significantly reduced in Re1A-/- B cells. Here we will further investigate a possible role for Re1A in regulation of potentially important anti-apoptotic genes. Using a retroviral transduction system, we will re-express anti-apoptotic genes showing impaired expression in RelA-/- B cells to determine their effect on TNF killing. The ability of retrovirus-transduced RelA-/- fetal liver hematopoietic precursors in restoring lymphocyte generation in Rag1-/- mice will also be determined.3) We have also identified a potentially important role for mature T cells in regulating survival of developing lymphocytes. Our results suggest that mature T cells may provide signals, which can counteract the cytotoxic effects of TNFR1. Here we will identify T cell subsets involved, and the nature of T cell derived factors responsible for this protective effect. Of particular interest as mediators of this T cell protective effect are CD4OL and IL-3. Here we will determine the role of CD4OL and IL-3 in inhibition of TNF killing of Re1A-/- developing B cells in vitro, and in rescuing Iymphopoiesis in vivo. These studies may also provide insights into development of strategies for enhancing lymphopoiesis under therapeutic settings.