Cooperative Mechanisms in IL-4-Induced Gene Expression

IL-4 诱导基因表达的协同机制

• 批准号: 7146699
• 负责人: MICHAEL T BERTON
• 金额: $ 30.32万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-12-01 至 2008-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7146699
• 关键词: 1-Phosphatidylinositol 3-Kinase; Asthma; Autoimmune Diseases; B-Lymphocytes; Binding; Biological; Biological Assay; CD4 Positive T Lymphocytes; Cell Line; Cells; Cessation of life; Complex; DNA; Data; Development; Disease; Drug Design; Event; Gene Activation; Gene Expression; Gene Expression Profiling; Gene Expression Regulation; Genes; Genetic Transcription; Goals; Hypersensitivity; IgE; IgG1; IgG4; Immune response; Immunoglobulin Class Switching; Immunoglobulin Genes; In Vitro; Infection; Inflammatory Response; Interleukin-4; Janus kinase; Kinetics; Knockout Mice; Knowledge; Laboratories; Lymphocyte; Maps; Mass Spectrum Analysis; Mediating; Modeling; Mus; Numbers; Outcome; Pathway interactions; Peptide Mapping; Phosphorylation; Phosphorylation Site; Play; Principal Investigator; Process; Protein-Serine-Threonine Kinases; Proteins; Publishing; Range; Regulation; Research; Retroviridae; Role; Serine; Serine Phosphorylation Site; Signal Pathway; Signal Transduction; Site; T-Lymphocyte; Testing; Th2 Cells; Time; Transactivation; Tyrosine Phosphorylation; Work; Yeasts; base; cell growth; cell type; cofactor; cytokine; expectation; immune function; in vivo; mutant; novel strategies; programs; protein protein interaction; receptor; response; transcription factor; yeast two hybrid system

The cytokine IL-4 is the single most important cytokine involved in the development and regulation of humoral immune responses. IL-4 drives the differentiation of naive CD4+ T cells into T helper type 2 (Th2) cells, directs isotype switching in B cells to IgE and IgG4 (IgG1 in mice), and regulates cell growth and death. As such, IL-4 has a pivotal role in regulating inflammatory responses, autoimmune diseases, immune responses to infection, and allergy, including asthma. IL-4 regulates this diverse array of immune functions in part through the activation of specific sets of genes in different cell types. IL-4 induces gene expression by inducing Janus kinase(Jak)-mediated activation of the transcription factor Stat6. Importantly, binding of Stat6 alone to DNA is not sufficient to activate transcription and cooperation of Stat6 with other factors is necessary. Recent evidence suggests that other signaling pathways, including the IRS-2/PI 3-kinase and PKC pathways, may be important for Stat6-dependent gene expression, but how other pathways cooperate with Stat6 is entirely unknown. The long-range goal of this project is to understand how IL-4 signaling regulates gene expression to mediate diverse biological effects. The objective of this application is to elucidate the mechanisms by which the JakJStat6 pathway cooperates with other signaling pathways and cellular factors to activate gene expression in response to IL-4. The central hypothesis for the proposed research is that IL-4-respcnsive gene expression is regulated not only by Jak-mediated tyrosine phosphorylation of Stat6 but also by serine kinase signaling pathways that converge on Stat6 and other required transcription cofactors to aromote their cooperative interaction. This hypothesis is supported by our recent demonstration that IL-4 induces serine ahosphorylation of Stat6. To test the central hypothesis, this proposal will pursue three specific aims: 1) determine the sites of Star6 serine phosphorylation, the kinetics and stability of serine phosphorylation and the role of IL-4R-mediated signaling events in Stat6 serine phosphorylation; 2) determine the role of IL-4-induced Stat6 serine phosphorylation in the regulation of Stat6-dependent gene expression; and 3) establish the mechanisms by which Stat6 cooperates with other necessary cofactors in the regulation of IL-4-dependent gene expression. Serine phosphorylation sites in Stat6 will be determined by peptide mapping and mass spectrometry. Their role in regulating Stat6 expression and function will be analyzed in Stat6-deficient B cells by retrovirus-mediated transduction. The proposed studies will focus on the regulation of the unrearranged IgG1 immunoglobulin gene in mouse B cells as a model for IL-4-induced gene expression. The proposed studies will significantly advance our current limited understanding of how IL-4 signaling and Stat6 regulate gene expression in lymphocytes as well as in other cell types. A better understanding of how IL-4-mediated signals cooperate to regulate gene expression will also allow development of novel approaches for modulating immune responses and disease processes regulated or influenced by IL-4.

细胞因子IL-4是参与体液免疫的发展和调节的最重要的细胞因子， 应答IL-4驱动初始CD 4 + T细胞分化为辅助性T细胞2型（Th 2）细胞，指导B细胞中的同种型转换， 细胞对IgE和IgG 4（小鼠中的IgG 1）的免疫应答，并调节细胞生长和死亡。因此，IL-4在调节细胞凋亡中具有关键作用。 炎症反应、自身免疫性疾病、对感染的免疫反应和过敏，包括哮喘。IL-4调节 这种多样化的免疫功能部分是通过激活不同细胞类型中的特定基因组来实现的。IL-4 通过诱导Janus激酶（Jak）介导的转录因子Stat 6的活化来诱导基因表达。重要的是， Stat 6单独与DNA结合不足以激活转录，Stat 6与其它因子的合作是必需的。 最近的证据表明，其他信号通路，包括IRS-2/PI 3-激酶和PKC通路，可能也是如此。 这对Stat 6依赖性基因表达很重要，但其他途径如何与Stat 6合作完全未知。的 该项目的长期目标是了解IL-4信号传导如何调节基因表达，以介导多种生物学特性。 方面的影响.本申请的目的是阐明JakJStat 6途径与其他细胞因子协同作用的机制。 信号传导途径和细胞因子以响应IL-4而激活基因表达。关于这个问题的中心假设 一项研究表明，IL-4反应基因的表达不仅受到Jak介导的酪氨酸磷酸化的调节， Stat 6，但也通过丝氨酸激酶信号通路，汇聚在Stat 6和其他所需的转录辅因子， 激发他们的合作互动。我们最近的研究证实IL-4诱导丝氨酸 Stat 6的去磷酸化。为了检验中心假设，本提案将追求三个具体目标：1）确定 Star 6丝氨酸磷酸化，丝氨酸磷酸化的动力学和稳定性以及IL-4 R介导的信号转导作用 2）确定IL-4诱导的Stat 6丝氨酸磷酸化在调节Stat 6丝氨酸磷酸化中的作用; Stat 6依赖性基因表达; 3）建立Stat 6与其他必要辅因子合作的机制 IL-4依赖性基因表达的调节。Stat 6中的丝氨酸磷酸化位点将通过肽测定来确定。 绘图和质谱分析。将在Stat 6缺陷型B中分析它们在调节Stat 6表达和功能中的作用。 细胞通过逆转录病毒介导的转导。这些研究将集中在非重排IgG 1的调控上 小鼠B细胞中的免疫球蛋白基因作为IL-4诱导的基因表达的模型。拟议的研究将大大 推进我们目前对IL-4信号传导和Stat 6如何调节淋巴细胞基因表达的有限理解， 其他细胞类型。更好地理解IL-4介导的信号如何协同调节基因表达也将使 开发用于调节由IL-4调节或影响的免疫应答和疾病过程的新方法。