Targeting hypoxia-inducible mediators to manipulate human adipocyte phenotype

描述(申请人提供)：肥胖与脂肪组织功能障碍有关，其特征是炎症增加和代谢异常，这是全身代谢性疾病的基础。低氧可能是肥胖患者脂肪组织功能障碍的根本原因。我们的初步数据表明，低氧诱导人脂肪组织巨噬细胞(ATM)的炎症反应和人脂肪细胞的己糖胺生物合成(HBS)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。我们的长期目标是在脂肪细胞和ATM基因修饰的基础上开发基于细胞的代谢性疾病的新疗法。我们的具体目标是确定低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，最后确定通过对人类脂肪细胞和ATM进行基因修饰来实现HBS和SAPK相关分子的敲除是否会使脂肪细胞向有利的代谢表型转变。我们的中心假设是：低氧直接或通过低氧诱导的ATM炎症诱导代谢功能障碍，其特征是脂肪细胞中的脂肪生成和HBS增加；这些过程受ERS和SAPK激活的调控；脂肪细胞中HBS相关的介质和ATM中的SAPK相关介质的基因敲除将诱导脂肪细胞中有利的代谢表型。目的确定低氧对人脂肪细胞ERS和代谢的调节作用，并确定抑制HBS是否能减弱低氧诱导的ERS和脂肪细胞的代谢反应。目的II将确定低氧在调节人类ATM炎症中的作用，并确定SAPK介体基因敲除是否减弱了低氧诱导的ATM炎症反应。目的III确定低氧诱导的ATM在调节脂肪细胞代谢中的作用，并确定在ATM中SAPK介体被敲除是否减弱了低氧对脂肪细胞代谢的影响。这一建议意义重大，因为它将确定人类组织中新的低氧诱导介质和脂肪组织功能障碍的机制，这将导致代谢性疾病的治疗。这一建议是创新的，因为它开发了一个模型系统，用于人类脂肪细胞和ATM的遗传修饰，目的是操纵脂肪细胞走向有利的代谢表型。

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.