A Critical Role for Stat2 in Type 1 Intferon-Induced Apoptosis

Stat2 在 1 型干扰素诱导的细胞凋亡中的关键作用

• 批准号: 6465237
• 负责人: ANA M GAMERO
• 金额: $ 16.29万
• 依托单位: TEMPLE UNIV OF THE COMMONWEALTH
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-23 至 2010-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6465237
• 关键词: Critical; Role; Stat2; Type; Intferon

Interferons (IFNs) have become extremely useful cytokines in the treatment of cancer and viral diseases due to their antigrowth, antiviral and immunomodulatory properties. The biological actions of IFNs are mediated by expression of early responsive genes regulated in part by the activation of the Jak/Stat signaling pathway. The antiproliferative actions of type I IFNs in Jurkat cells, a human T cell line, require activation of a set of T cell receptor (TCR) signaling components: protein tyrosine kinases and a protein tyrosine phosphatase. Stimulation of Jurkat cells with IFN-beta induces nuclear translocation of NFAT, a transcription factor activated in response to TCR stimulation. To explore the role of NFAT in type I IFN signaling, Jurkat cells were transfected with a NFAT driven luciferase reporter. Incubation of cells with IFN-beta inhibited PMA and ionomycin induced NFAT dependent transcription. This negative regulatory effect was reversed by expression of a dominant negative Stat1 mutant. Conversely, treatment of Jurkat cells with ionomycin inhibited IFN-beta induced transcriptional activity of an ISRE driven luciferase reporter that is reversible by pretreatment of cells with cyclosporine A (CsA), a specific inhibitor of calcineurin, the upstream activator of NFAT. Incubation of normal peripheral blood T cells with PMA plus ionomycin inhibited the expression of specific IFN inducible genes and CsA restored expression of these genes. Moreover, Stat1 and NFAT proteins are associated in T cells. These results provide first evidence for the involvement of NFAT in type I IFN regulated signaling cascades in T cells. We will test the hypothesis that NFAT and Stat1 reciprocally repress each others’ transcriptional activities by performing the following aims: (1) Determine whether incubation of T cells with IFN-beta in combination with T-cell receptor agonists alters NFAT or Stat1 activation, binding to DNA or nuclear localization. (2) Determine the domains of Stat1 and NFAT that are required for these proteins to interact and whether this interaction is required for these factors to regulate gene expression.

干扰素（IFN）已变得极其 细胞因子在治疗癌症和病毒性疾病中发挥着重要作用 抗生长、抗病毒和免疫调节特性。 干扰素的表达是由部分调节的早期反应基因的表达介导的 通过激活 Jak/Stat 信号通路。 I 型干扰素在人类 T 细胞系 Jurkat 细胞中的作用需要 一组 T 细胞受体 (TCR) 信号传导成分的激活：蛋白质 酪氨酸激酶和蛋白酪氨酸磷酸酶的刺激。 具有 IFN-β 的细胞会诱导 NFAT（一种转录）的核转位 响应 TCR 刺激而激活的因子 探索 NFAT 的作用。 在 I 型 IFN 信号传导中，Jurkat 细胞被 NFAT 驱动的转染 细胞与 IFN-β 抑制的 PMA 一起孵育。 离子霉素诱导 NFAT 依赖性转录。 显性失活 Stat1 突变体的表达可逆转该效应。 离线，用离子霉素抑制 IFN-β 处理 Jurkat 细胞 ISRE 驱动的荧光素酶报告基因的诱导转录活性 通过用环孢素 A (CsA) 预处理细胞可逆，环孢素 A 是一种特异性的 钙调磷酸酶抑制剂，NFAT 的上游激活剂。 PMA加离子霉素抑制正常外周血T细胞 特定 IFN 诱导基因的表达和 CsA 恢复了 此外，Stat1 和 NFAT 蛋白与 T 细胞相关。 这些结果为 NFAT 参与 I 型 IFN 提供了第一个证据 我们将检验以下假设： NFAT 和 Stat1 通过以下方式相互抑制彼此的转录活性 执行以下目标： (1) 确定 T 细胞是否孵育 IFN-β 与 T 细胞受体激动剂联合改变 NFAT 或 Stat1 激活、与 DNA 结合或核定位 (2) 确定。 Stat1 和 NFAT 的结构域是这些蛋白质相互作用所必需的 这些因素是否需要这种相互作用来调节基因 表达。