Regulation and Function of MEKK3 in Dendritic Cells

MEKK3在树突状细胞中的调控和功能

• 批准号: 7061705
• 负责人: BING SU
• 金额: $ 36.27万
• 依托单位: UNIVERSITY OF TX MD ANDERSON CAN CTR
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-06-01 至 2006-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7061705
• 关键词: biological signal transduction; cell differentiation; cytokine receptors; dendritic cells; developmental immunology; enzyme activity; gene mutation; genetic regulation; genetically modified animals; hematopoietic stem cells; immune response; interleukin 1; laboratory mouse; mitogen activated protein kinase; phosphorylation; protein localization; toll like receptor

DESCRIPTION (provided by applicant): Toll-like receptors (TLRs) play a central role in innate and adaptive immunity. TLRs have evolved to detect infection by recognizing the conserved molecular patterns of microorganisms, and such recognition leads to the induction of innate and adaptive immunity through the activation and maturation of dendritic cells (DCs), the most potent professional antigen-presenting cells (APCs). The central question regarding the induction of both innate and adaptive immune responses is how the immune receptor-mediated signals are transduced intracellularly, thereby leading to the nuclear gene expression and immune effector functions. The mitogen-activated protein kinase (MAPK) and the IkappaBalpha kinase (IKK) are the main targets of the TLR pathways in DCs and other cells in immune system. MEKK3 is a serine/threonine protein kinase that belongs to the MAPK kinase kinase family. We disrupted the Mekk3 gene in mice and found that MEKK3 is a key signal transducer of the IL-1R and TLR4 signaling to the downstream MAPK and IKK pathways. Because the IL-1 receptor (IL-1R)/TLR gene family is central for the multiple aspects of DC biology, we hypothesize that MEKK3 plays an essential role in DC function. The proposed studies are designed to elucidate the molecular mechanisms of MEKK3 signaling and MEKK3 function in DCs through the IL-1R-TLR pathways. Four Specific Aims are proposed: (1) to define the molecular mechanism of MEKK3 activation by IL-1R-TLR4. (2) to determine the structural basis of MEKK3 specificity in the IL-1R-TLR4 pathways and to isolate and clone MEKK3 regulators and targets in DCs. (3) to determine the role of MEKK3 in DC activation and maturation. (4) to investigate the role of MEKK3 in DC differentiation in vivo. We will determine MEKK3 intracellular localization, phosphorylation, enzymatic activity, and MEKK3 association with adaptor molecules in the IL-1R-TLR pathways. We will determine the MEKK3 functional domains and clone MEKK3 regulators in DCs. We will establish MEKK3-deficient DCs using Mekk3-/- embryos, Mekk3 siRNA, and Mekk3 floxed mice and determine the role of MEKK3 in MAPK and IKK-NF-kappaB activation, and in DC lineage differentiation, activation and maturation. In addition to revealing the regulation and function of MEKK3 in DCs, the outcome from this study will also provide conceptual and material resources for studying MEKK3 and its homologues in many other physiological and pathological processes. Most importantly, this study may discover novel molecular targets for therapeutic interventions for treating diseases such as arthritis, sepsis, atherosclerosis, autoimmunity, and cancer.

描述（由申请人提供）：Toll 样受体（TLR）在先天性和适应性免疫中发挥核心作用。 TLR 已进化为通过识别微生物的保守分子模式来检测感染，这种识别可通过树突状细胞 (DC)（最有效的专业抗原呈递细胞 (APC)）的激活和成熟来诱导先天性和适应性免疫。关于诱导先天性和适应性免疫反应的核心问题是免疫受体介导的信号如何在细胞内转导，从而导致核基因表达和免疫效应器功能。丝裂原激活蛋白激酶 (MAPK) 和 IkappaBalpha 激酶 (IKK) 是 DC 和免疫系统其他细胞中 TLR 通路的主要靶标。 MEKK3 是一种丝氨酸/苏氨酸蛋白激酶，属于 MAPK 激酶激酶家族。我们破坏了小鼠中的 Mekk3 基因，发现 MEKK3 是 IL-1R 和 TLR4 信号传导至下游 MAPK 和 IKK 途径的关键信号转导器。由于 IL-1 受体 (IL-1R)/TLR 基因家族对于 DC 生物学的多个方面至关重要，因此我们假设 MEKK3 在 DC 功能中发挥重要作用。拟议的研究旨在通过 IL-1R-TLR 途径阐明 DC 中 MEKK3 信号传导和 MEKK3 功能的分子机制。提出了四个具体目标：（1）明确IL-1R-TLR4激活MEKK3的分子机制。 (2)确定IL-1R-TLR4途径中MEKK3特异性的结构基础，并分离和克隆DC中的MEKK3调节剂和靶标。 (3)确定MEKK3在DC激活和成熟中的作用。 (4)研究MEKK3在体内DC分化中的作用。我们将确定 MEKK3 的细胞内定位、磷酸化、酶活性以及 MEKK3 与 IL-1R-TLR 途径中的接头分子的关联。我们将确定 MEKK3 功能域并在 DC 中克隆 MEKK3 调节因子。我们将使用 Mekk3-/- 胚胎、Mekk3 siRNA 和 Mekk3 floxed 小鼠建立 MEKK3 缺陷型 DC，并确定 MEKK3 在 MAPK 和 IKK-NF-kappaB 激活以及 DC 谱系分化、激活和成熟中的作用。该研究成果除了揭示MEKK3在DC中的调控和功能外，还将为研究MEKK3及其同源物在许多其他生理和病理过程中的概念和物质资源。最重要的是，这项研究可能会发现治疗关节炎、败血症、动脉粥样硬化、自身免疫和癌症等疾病的治疗干预的新分子靶点。