Targeting hypoxia-inducible mediators to manipulate human adipocyte phenotype

描述（由申请人提供）：肥胖与脂肪组织功能障碍状态相关，其特征是炎症增加和代谢异常，这是全身性代谢疾病的基础。缺氧被认为是肥胖中脂肪组织功能障碍的根本原因。我们的初步数据表明，缺氧诱导人脂肪组织巨噬细胞（ATM）和己糖胺生物合成（HBS）的炎症和脂肪生成，内质网应激（ERS）和应激激活蛋白激酶（SAPK）调节这些过程。我们的长期目标是开发基于脂肪细胞和ATM基因修饰的代谢疾病的新型细胞疗法。我们提出的具体目标是确定缺氧对人类脂肪细胞代谢和ATM炎症反应的影响，确定ERS和SAPK激活在调节这些过程中的作用，确定ATM在调节脂肪细胞代谢中的作用，最后确定人类脂肪细胞和ATM的基因修饰是否实现HBS和SAPK相关分子的敲低，从而使脂肪细胞转向有利的代谢表型。我们的主要假设是：缺氧直接或通过缺氧诱导的ATM炎症诱导代谢功能障碍，其特征是脂肪细胞中脂肪生成和HBS增加；这些过程是由ERS和SAPK激活调控的；脂肪细胞中hbs相关介质和ATM中sapk相关介质的基因敲低将在脂肪细胞中诱导有利的代谢表型。目的：明确缺氧在调节人脂肪细胞内质网和代谢中的作用，并确定抑制HBS是否会减弱缺氧诱导的脂肪细胞内质网和代谢反应。Aim II将确定缺氧在调节人类ATM炎症中的作用，并确定SAPK介质敲低是否会减弱缺氧诱导的ATM炎症反应。Aim III将确定缺氧引发的ATM在调节脂肪细胞代谢中的作用，并确定ATM中SAPK介质的敲低是否会减弱缺氧对脂肪细胞代谢的影响。这一建议具有重要意义，因为它将确定新的缺氧诱导介质和人体组织中脂肪组织功能障碍的机制，这将导致代谢疾病的治疗。这个建议是创新的，因为它开发了一个人类脂肪细胞和ATM的遗传修饰模型系统，目标是操纵脂肪细胞向有利的代谢表型发展。

DESCRIPTION (provided by applicant): Obesity is associated with a state of adipose tissue dysfunction characterized by increased inflammation and aberrant metabolism that underlies systemic metabolic disease. Hypoxia is a putative root cause of adipose tissue dysfunction in obesity. Our preliminary data demonstrate that hypoxia induces inflammation in human adipose tissue macrophages (ATM) and hexosamine biosynthesis (HBS) and lipogenesis in human adipocytes, and that endoplasmic reticulum stress (ERS) and stress-activated protein kinases (SAPK) regulate these processes. Our long-term goal is to develop novel cell-based therapy for metabolic disease based on genetic modification of adipocytes and ATM. Our proposal-specific goals are to define the effects of hypoxia on human adipocyte metabolism and ATM inflammatory responses, to define the role of ERS and SAPK activation in regulating these processes, to define the role of ATM in regulating adipocyte metabolism, and finally, to determine if genetic modification of human adipocytes and ATM to accomplish knockdown of HBS and SAPK- related molecules shifts adipocytes towards a favorable metabolic phenotype. Our central hypotheses are: that hypoxia induces metabolic dysfunction characterized by increased lipogenesis and HBS in adipocytes, directly as well as via hypoxia-induced ATM inflammation; that these processes are regulated by ERS and SAPK activation; and that genetic knockdown of HBS-related mediators in adipocytes and SAPK-related mediators in ATM will induce a favorable metabolic phenotype in adipocytes. Aim I will define the role of hypoxia in regulating ERS and metabolism in human adipocytes and determine if inhibition of HBS attenuates hypoxia- induced ERS and metabolic responses in adipocytes. Aim II will define the role of hypoxia in regulating human ATM inflammation and determine if SAPK mediator knockdown attenuates hypoxia-induced ATM inflammatory responses. Aim III will define the role of hypoxia-primed ATM in regulating adipocyte metabolism and determine if SAPK mediator knockdown in ATM attenuates hypoxia's effects on adipocyte metabolism. This proposal is significant because it will identify novel hypoxia-inducible mediators and mechanisms of adipose tissue dysfunction in human tissues that will lead to therapy for metabolic disease. This proposal is innovative because it develops a model system for genetic modification of human adipocytes and ATM with the goal of manipulating adipocytes towards a favorable metabolic phenotype.