Regulation and function of TBK1-mTOR crosstalk

项目摘要 细胞和有机体的动态平衡需要细胞整合不同的局部和系统信号 信令网络。合成代谢激酶mTOR(雷帕霉素的机制靶点)整合了营养和 生长因子的可用性，在调节新陈代谢、肿瘤发生、 和免疫功能。MTOR包括两个功能不同的多亚单位复合体的催化核心， MTORC1和mTORC2。不足为奇的是，mTOR功能异常会导致病理状态，包括 与肥胖相关的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规则和功能的机械性理解存在重大差距，特别是mTOR如何 与其他重要的调节系统通信，以控制细胞和生物生理学。近期工作 为这一提议提供了科学前提，这证明了非正则 天然免疫激酶TBK1(坦克结合激酶1)磷酸化mTOR(位于S2159上)以增加mTORC1 和mTORC2在先天免疫激动剂(例如，病毒dsRNA模拟物)刺激细胞时的信号转导 多聚(I：C)；细菌内毒素)、生长因子(EGF)或激素(胰岛素)在培养细胞和体内(Bodur等人)。 2018年；Toey等人。2021年)。这项工作连接了两个生理上重要的信号系统，这是以前没有的 以善于沟通而闻名。传统上，TBK1对微生物产生的信号做出反应，启动一线宿主 防御病毒和细菌病原体。这些信号导致TBK1的磷酸化和激活， 这驱动了I型干扰素(如IFNb)和干扰素刺激基因(ISGs)的产生。更新的工作 TBK1涉及更广泛的功能，包括改善饮食诱导过程中的血糖控制 肥胖和肿瘤发生通过定义不明确的下游介体。我们最近证明了老鼠 S2159A等位基因的磷酸化缺陷表现为全身性胰岛素抵抗 和高血糖在饮食诱导的肥胖中，但不是瘦状态(Bodur等人。2022年)。巨噬细胞和 这些小鼠的脂肪组织显示IFNb和抗炎ISG IL-10 AS的表达减少 以及促炎症细胞因子的表达增加(Bodur等人)。2022年)。这件事的首要目标是 其应用是阐明TBK1-mTOR串扰在细胞和体内的调节和功能。我们会 使用生化、细胞和分子方法更好地定义TBK1如何促进mTORC1和 在没有微生物来源信号的情况下发出mTORC2信号(目标1)。我们还将调查TBK1是如何- MTOR信号对饮食诱导肥胖的胰岛素抵抗、高血糖和炎症的保护作用 但通过在体内研究小鼠和培养中的原代细胞来研究瘦肉状态(目标2)。这个项目不仅将 阐明控制TBK1-mTOR信号的基本机制，也将促进我们的知识 整合先天免疫和代谢信号以预防肥胖相关代谢的机制 疾病，特别是II型糖尿病，这是一种在世界范围内日益流行的令人震惊的疾病。

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.