p62/SQSTM1通过清除泛素化Perilipin参与脂肪组织稳态调控的机制研究

Obesity is accompanied by excessive accumulation fat with imbalance energy homeostasis. The intracellular storage and utilization of lipids are critical to maintain cellular energy homeostasis. Perilipin A is the most abundant protein on adipocyte lipid droplets and is essential for lipid storage and lipolysis. Autophagy is a lysosomal pathway by which intracellular organelles and proteins are degraded to supply the cell with energy and to maintain cellular homeostasis. We found Perilipin can be ubiquitinated and selectively degraded by autophagy-lysosome pathway. We also determined that Perilipin interacts directly with selective autophagy receptor p62/SQSTM1. However, the relationship between Perilipin ubiquitinition and adipose tissue homeostasis is not clearly known. Therefore, we hypothesized that ubiquitinated Perilipin can be selectively degraded through p62/SQSTM1 and participated in the adipocytes homeostasis. We will detect the mechnism of Perilipin ubiquitination and how Perilipin ubiquitination regulate lipid metabolism by conducting lentivirious of point mutation or ubiquitin ligase，so as to find a potential target of treating obesity.

肥胖是伴随能量稳态失衡出现的体内脂肪过度累积，脂肪细胞内的脂滴是调控机体脂质和能量平衡的关键。在成熟脂肪细胞内，脂滴包被蛋白Perilipin是甘油三酯贮存和分解的关键分子，而自噬对细胞的自我更新、蛋白的降解和脂代谢具有重要调控作用。我们发现，Perilipin是一个可被泛素化的蛋白，可由自噬溶酶体途径降解。同时，Perilipin与选择性自噬受体p62/SQSTM1在细胞水平具有相互作用关系。然而，Perilipin的泛素化修饰及自噬性降解与脂肪组织稳态调控的关系尚不明确。因此，我们猜测泛素化的perilipin可通过p62/SQSTM1被自噬性降解并参与脂质的贮存和分解。我们将从细胞和整体水平全面阐述Perilipin的泛素化调控机制，通过构建泛素化位点突变及特异泛素连接酶的慢病毒进一步研究Perilipin泛素化修饰对脂肪组织稳态调控的作用，为肥胖及相关代谢性疾病的治疗提供潜在靶点。

研究背景：能量代谢紊乱是肥胖发生的主要原因，而脂肪组织在能量代谢调控过程中发挥关键作用，从分子水平研究脂肪细胞的能量储存和利用是预防和治疗肥胖的新热点。Kisspeptin是下丘脑促性腺激素释放激素（GnRH）神经元的关键调节剂，研究表明Kiss1R激动剂对女性生殖系统疾病具有治疗潜力。近年来，也有文献报道其在能量代谢中发挥潜在作用，但Kisspeptin/Kiss1R对脂肪组织稳态的调控机制尚不明确。.主要研究内容：探讨Kiss1R激动剂对机体能量代谢的影响及脂肪组织稳态的调控机制。.重要结果、关键数据：构建高脂喂养诱导肥胖的雌、雄小鼠模型，给予正常和肥胖小鼠Kiss1R激动剂TAK448（7.2nmol/d）皮下注射干预8周（CON组、HFD组、CON+TAK组、HFD+TAK组, n=6-10）后，采用体脂分析、糖耐量实验、胰岛素耐量实验、代谢笼、qRT-PCR、Western Blot等实验方法以及蛋白质组学和代谢组学等多组学技术，探讨Kiss1R激动剂对机体能量代谢的影响和脂肪组织稳态的调控机制。结果表明，和雄鼠相比，TAK448对雌鼠棕色脂肪和机体能量代谢的影响较为显著。TAK448干预可显著增加雌性肥胖小鼠的棕色脂肪含量，但其产热和能量消耗却明显减少。进一步的联合组学分析证明Kiss1R激动剂可通过抑制雌鼠棕色脂肪产热能力而对机体的能量稳态调节发挥重要作用。.科学意义：本研究证明Kiss1R激动剂TAK448对小鼠机体能量代谢及脂肪组织稳态的调控具有性别差异性及脂肪组织特异性，提示Kiss1R是减重药物研发的重要靶点。