Regulation and function of TBK1-mTOR crosstalk

项目摘要 细胞和生物体内平衡需要细胞整合不同的局部和系统线索 信令网络合成代谢激酶mTOR（雷帕霉素的机制靶点）整合营养和 生长因子的可用性，在调节代谢，肿瘤发生， 和免疫功能。mTOR包含两个功能不同的多亚基复合物的催化核心， mTORC 1和mTORC 2。毫不奇怪，异常的mTOR功能有助于病理状态，包括 肥胖相关的II型糖尿病、癌症和免疫紊乱。尽管mTOR在生理上很重要， 我们对mTOR调节和功能的机械理解存在重大差距，特别是mTOR如何 与其他重要的调节系统沟通，以控制细胞和生物体的生理。最近的工作 从我们的实验室提供了这个建议的科学前提，这表明，非典型的 先天免疫激酶TBK 1（TANK结合激酶1）磷酸化mTOR（在S2159上）以增加mTORC 1 以及在用先天免疫激动剂（例如，病毒dsRNA模拟物 聚（I：C）;细菌LPS）、生长因子（EGF）或激素（胰岛素）（Bodur et al. 2018; Tooley et al. 2021）。这项工作将两个以前没有的生理学上重要的信号系统联系起来 知道沟通。传统上，TBK 1响应微生物来源的信号，启动一线宿主 防御病毒和细菌病原体。这些信号导致TBK 1的磷酸化和活化， 其驱动I型干扰素的产生（例如，IFNb）和IFN刺激基因（ISG）。最近的工作 提示TBK 1具有更广泛的功能，包括在饮食诱导的糖尿病期间改善血糖控制。 肥胖和肿瘤发生通过不明确的下游介质。我们最近证明， 携带“TBK 1抗性”、磷酸化缺陷的Mtor S2159 A等位基因显示全身胰岛素抗性 饮食诱导的肥胖而非消瘦状态下的高血糖（Bodur et al. 2022）。巨噬细胞和 来自这些小鼠的脂肪组织显示IFNb和抗炎ISG IL-10的表达降低， 以及促炎细胞因子的表达升高（Bodur等人，2022）。这个项目的首要目标是 本申请旨在阐明TBK 1-mTOR串扰在细胞和体内的调节和功能。我们将 采用生物化学，细胞和分子方法，以更好地确定TBK 1如何促进mTORC 1， 在不存在微生物来源的信号的情况下的mT 0 RC 2信号传导（Aim 1）。我们还将研究TBK 1- mTOR信号传导在饮食诱导的肥胖中防止胰岛素抵抗、高血糖和炎症 但通过研究小鼠体内和培养中的原代细胞，不存在瘦状态（Aim 2）。该项目不仅将 阐明TBK 1-mTOR信号转导控制的基本机制，但也将推进我们的知识 整合先天免疫和代谢信号的机制，以防止肥胖相关的代谢 糖尿病是一种慢性疾病，特别是II型糖尿病，这是一种在全世界范围内日益增长和令人震惊的流行病。

Project Summary Cellular and organismal homeostasis requires integration of diverse local and systemic cues by cell signaling networks. The anabolic kinase mTOR (mechanistic target of rapamycin) integrates nutrient and growth factor availability, playing critical roles in cellular processes that modulate metabolism, tumorigenesis, and immune function. mTOR comprises the catalytic core of two functionally distinct, multi-subunit complexes, mTORC1 and mTORC2. Not surprisingly, aberrant mTOR function contributes to pathological states including obesity-linked type II diabetes, cancer, and immune disorders. Despite the physiological importance of mTOR, major gaps exist in our mechanistic understanding of mTOR regulation and function, particularly how mTOR communicates with other important regulatory systems to control cell and organismal physiology. Recent work from our lab provides the scientific premise for this proposal, which demonstrated that the non-canonical innate immune kinase TBK1 (TANK binding kinase 1) phosphorylates mTOR (on S2159) to increase mTORC1 and mTORC2 signaling upon cellular stimulation with innate immune agonists (e.g., the viral dsRNA mimetic poly(I:C); bacterial LPS), growth factors (EGF), or hormones (insulin) in cultured cells and in vivo (Bodur et al. 2018; Tooley et al. 2021). This work linked two physiologically important signaling systems not previously known to communicate. Classically, TBK1 responds to microbial-derived signals to initiate first-line host defense against viral and bacterial pathogens. These signals lead to phosphorylation and activation of TBK1, which drives ]production of type I interferons (e.g., IFNb) and IFN-stimulated genes (ISGs). More recent work implicates TBK1 in a broader range of functions including improved glycemic control during diet-induced obesity and tumorigenesis through poorly defined downstream mediators. We demonstrated recently that mice bearing a “TBK1 resistant”, phosphorylation deficient Mtor S2159A allele display systemic insulin resistance and hyperglycemia in the diet-induced obese but not the lean state (Bodur et al. 2022). Macrophages and adipose tissue from these mice display reduced expression of IFNb and the anti-inflammatory ISG IL-10 as well as elevated expression of pro-inflammatory cytokines (Bodur et al. 2022). The overarching goal of this application is to elucidate the regulation and function of TBK1-mTOR crosstalk in cells and in vivo. We will employ biochemical, cellular, and molecular approaches to better define how TBK1 promotes mTORC1 and mTORC2 signaling in the absence of microbial-derived signals (Aim 1). We will also investigate how TBK1- mTOR signaling protects against insulin resistance, hyperglycemia, and inflammation in the diet-induced obese but not lean state by studying mice in vivo and primary cells in culture (Aim 2). This project will not only elucidate basic mechanisms underlying control of TBK1-mTOR signaling but will also advance our knowledge of mechanisms that integrate innate immune and metabolic signals to protect against obesity-linked metabolic disease, in particular type II diabetes, a disease with growing and alarming prevalence worldwide.