IRF-1 AND PROLACTIN IN T CELL ACTIVATION

肽激素催乳素（PRL）对两者都有深远的影响。 细胞增殖和分化的各种组织，但 其作为免疫调节剂的作用尚未明确。PRL扮演的角色 作为一种新的T和B细胞细胞因子， PRL受体（PRL-R），一个成员， 细胞因子受体超家族的一员，在免疫系统的细胞上表达。 系统，其中一些细胞也合成和分泌 生物活性PRL。这项建议的长远目标是 了解PRL的免疫调节特性。作为一个模型系统， 为了研究PRL作为T细胞细胞因子的作用，我们使用大鼠 Nb 2 T淋巴瘤细胞需要PRL生长。PRL的主要目标 Nb 2 T细胞中的刺激因子是转录因子干扰素 调节因子-1（IRF-1）。在T细胞中，PRL刺激双相 IRF-1的表达，首先在G1活化期间，然后在G1/S期间再次表达 过渡，其表达与DNA合成密切相关， 随后的细胞增殖。我们最近的研究表明 细胞因子信号转导分子 转录”或Stat，以及细胞周期调节的转录 含有视网膜母细胞瘤蛋白（Rb）的复合物作为可能的PRL信号传导 在IRF-i启动子处的分子。我们的工作假设是PRL和 它的受体参与G1活化的信号传导， 活化T细胞的S期进展。细胞因子和细胞周期 信号分子在IRF-I启动子处被激活， 方式 我们进一步表明，转录因子IRF-1是一个转录因子。 在T细胞的这些不同阶段，PRL作用的核介质 周期 这些研究旨在阐明细胞因子信号是如何 转导可以与细胞周期控制信号整合， 调节IRF-1表达，以及IRF-1如何对T细胞 活化和增殖。研究的目的是：1）表征 G1期与S期IRF-1启动子的双相PRL反应， 并阐明Stat和Rb蛋白如何参与这些反应。 启动子元件的突变分析与 蛋白质！DNA相互作用将有助于识别顺式作用元件， 对IRF-1基因的PRL刺激重要的反式作用因子; （2）研究IRF-1在T细胞中的功能和PRL的作用。cd 8 + T细胞 来自胸腺细胞和脾细胞，代表不同阶段的 发展将作为PRL的潜在目标进行分析 免疫调节 IRF-1靶基因也将通过差异表达克隆。 显示PCR，作为了解PRL（细胞因子信号）和 IRF-1（一种细胞因子靶标）调节T细胞活化和增殖。 这些研究代表了一个全面的分子，遗传，生化 和免疫学方法来定义细胞因子信号是如何 整合细胞周期信号，调节IRF-1基因表达， T淋巴细胞。了解PRL如何调节生物功能 T细胞的免疫调节特性应阐明PRL，和 为神经内分泌-免疫系统相互作用提供了新的见解。

The peptide hormone prolactin (PRL) exerts a profound effect on both cellular proliferation and differentiation in a variety of tissues, but its role as an immunomodulator has not been well-defined. That PRL plays a potentially important role as a novel T and B cell cytokine has been strengthened by the observations that the PRL receptor (PRL-R), a member of the cytokine receptor superfamily, is expressed on cells of the immune system, and that some of these cells also synthesize and secrete biologically-active PRL. The long-term objective of this proposal is to understand the immunoregulatory properties of PRL. As a model system for investigating the role of PRL as a T cell cytokine, we are using the rat Nb2 T lymphoma cells which require PRL for growth. A major target of PRL stimulation in Nb2 T cells is the transcription factor, interferon regulatory factor-1 (IRF-1). In T cells, PRL stimulates the biphasic expression of IRF-1, first during G1 activation, and again over G1/S transition, where its expression is tightly linked to DNA synthesis and subsequent cell proliferation. Our recent studies have implicated the cytokine signaling molecules "signal transducer and activator of transcription" or Stat, and the cell cycle-regulated transcription complex containing retinoblastoma protein (Rb) as possible PRL signaling molecules at the IRF-i promoter. Our working hypothesis is that PRL and its receptors are involved in signaling for G1 activation as well as for S phase progression in activated T cells. Both cytokine and cell cycle signaling molecules are activated at the IRF-I promoter in a biphasic manner. We further suggest that the transcription factor IRF-1 is a nuclear mediator of PRL action during these distinct phases of the T cell cycle. The proposed studies aim to elucidate how cytokine signal transduction may be integrated with cell cycle control signals to regulate IRF-1 expression, and how IRF-1 may be important for T cell activation and proliferation. Studies are proposed to: 1) Characterize the biphasic PRL response at the IRF-1 promoter during G1 versus S phase, and to elucidate how Stat and Rb proteins participate in these responses. Mutational analysis of promoter elements coupled with studies of protein!DNA interactions will help to identify cis-acting elements and the transacting factors important for PRL stimulation of the IRF-1 gene; and 2) Investigate IRF-1 function and PRL action in T cells. CD8+ T cells from thymocytes and splenocytes representing different stages of development will be analyzed as potential targets of PRL immunomodulation. IRF-1 target genes will also be cloned by differential display PCR, as one way of understanding how PRL (a cytokine signal) and IRF-1 (one cytokine target) modulate T cell activation and proliferation. These studies represent a comprehensive molecular, genetic, biochemical and immunological approach to defining how cytokine signals are integrated with cell cycle signals to regulate IRF-1 gene expression in T lymphocytes. Understanding how PRL modulates the biological functions of T cells should elucidate the immunoregulatory properties of PRL, and provide new insights into neuroendocrine-immune system interactions.