Nrf2通过调控脂肪因子的分泌影响小鼠血管稳态和衰老的机制研究

.　　Adipose tissue (AT) regulates overall metabolism and vascular homeostasis via synthesizing and secreting numerous enzymes, growth factors, cytokines and hormones. Excessive accumulation of AT has been considered as one of the main factors that cause cardiovascular (CV) disease, metabolic disease and accelerated aging etc. .　We have previously found that specific ablation of Nrf2 in AT enhanced glucolipid metabolism and energy expenditure of mice, accompanied with elevated expression and secretion of FGF21 in AT that is a major molecular controller in maintaining and remodeling of overall metabolism and vascular homeostasis. .　In this project, we are planning to investigate the Nrf2-modulated changes of phenotype and function of AT, including eventual browning of the white AT accompanying with beneficial effects on CV aging; possibility of prevention of the atherosclerogenesis. .　More over, we are planning to perform transcriptome sequencing analysis to identify the genes of which the transcriptional activity could be altered by knockdown of Nrf2 in perivascular AT (PVAT), following examination of their impacts on vascular disease and aging, via our well-established technical platform for studying of the mechanism of aging of vascular smooth muscle cells (VSMCs) and vascular endothelial cells (VECs), and to understand the molecular signaling network within AT through which Nrf2 modulates vascular homeostasis and aging..　The outcome of this investigation could serve as a fundamental base for prevention and treatment of diet- and aging-induced obesity with associated metabolic disorders, CV disease, delaying of aging, especially delaying of the vascular aging, by operation on AT..

脂肪组织（AT）可通过分泌脂肪因子调控机体内代谢和血管稳态。体内AT的过量堆积更是包括心血管疾病、代谢性疾病、衰老等的重要诱因。我们前期已证明在小鼠AT中特异性敲除Nrf2，一个增强细胞氧化应激防御的转录因子，可导致小鼠糖脂代谢和能量代谢的增加，并伴随着对调控代谢和血管稳态有重大影响的FGF21的表达和分泌的增加。本课题中，我们计划使用该小鼠模型，研究Nrf2调控的小鼠AT表型和功能的改变，包括小鼠白色AT向棕色AT的转化和对血管衰老的影响，对小鼠发生发展动脉粥样硬化的影响。利用转录组测序分析AT内基因的差异性表达，寻找AT中可被Nrf2调控的脂肪因子，并利用我们已经成熟的研究血管平滑肌细胞和血管内皮细胞衰老的技术平台，验证其对血管稳态和衰老的影响，进而构建Nrf2通过调控AT的分泌功能影响血管稳态和衰老的信号网络，为将来可能应用AT预防和治疗饮食和衰老导致的心血管疾病和衰老提供理论基础。

脂肪组织可通过分泌脂肪因子调控机体内代谢和血管稳态。体内脂肪组织的过量堆积更是包括心血管疾病、代谢性疾病、衰老等的重要诱因。.Nrf2是一个增强细胞氧化应激防御的转录因子。本课题中，我们使用了脂肪组织内特异性敲除Nrf2的小鼠模型以及沉默了Nrf2表达的各种脂肪组织内的细胞模型，包括小鼠3T3-L1脂肪细胞和小鼠RAW264.7巨噬细胞，研究了Nrf2对细胞的基因表达以及分泌功能的影响。Nrf2在衰老缺氧的脂肪细胞中有维持细胞能量代谢和糖脂代谢稳态的作用；在巨噬细胞中，Nrf2不仅调节细胞的氧化应激状态，并且对巨噬细胞的极化及炎症因子的表达和分泌有着十分重要的调控作用。这些研究揭示了Nrf2在脂肪组织中多重功能，以及通过调节脂肪组织的分泌功能，包括脂肪因子和炎症因子调控血管的衰老和稳态。.本项目也研究了脂肪分泌因子FGF21对血管衰老的调节作用。FGF21在大鼠血管平滑肌细胞中可促进血管平滑肌细胞的衰老和成骨样转化；在人脐静脉血管内皮细胞（HUVECs）中则可通过上调Sirt1通路延缓HUVECs的复制性衰老和H2O2刺激导致的应激性衰老，进而我们提出了在HUVECs的衰老进程中存在着类似胰岛素抵抗的“FGF21抵抗”的假设。.作为本课题的延伸，我们发现通过使用健康年轻志愿者的血浆干预衰老的HUVECs可显著延缓衰老HUVECs的衰老表型，通过RNA-Seq分析找出了6个在衰老HUVECs中表达可被年轻血浆所逆转的基因，其中的5个基因可主动调控内皮细胞的衰老。结合这些基因所参与的分子调控通路，我们认为年轻血浆可通过多重通路延缓血管内皮细胞的衰老。.本项目系统性研究了Nrf2对脂肪组织内的主要组分脂肪细胞和巨噬细胞的分别的影响及作用机制，揭示了Nrf2在脂肪组织内的多重调控功能。同时也系统性研究了FGF21对血管主要细胞血管内皮细胞和血管平滑肌细胞的不同功能和作用机制，揭示了FGF21在延缓血管衰老和维持血管稳态中的关键作用。本项研究可为将来可能的应用调控脂肪组织来延缓血管衰老，预防和治疗衰老导致的心血管疾病提供理论基础。