PLIN5在莱菔硫烷促进肝脏脂肪滴降解中的作用及机制研究

脂肪滴(LDs)是储脂细胞器，长期营养或能量过剩导致LDs代谢超负荷时，LDs异常蓄积致脂代谢紊乱，是代谢性疾病的关键诱因。富含于西兰花中的莱菔硫烷(SFN)可减轻LDs异常蓄积，其机制尚需揭示。申请者发现SFN可降低胞浆PLIN5蛋白表达，推测与其磷酸化并转核有关，同时SFN增加LDs脂解酶基因表达及线粒体生物合成。因此提出“SFN磷酸化PLIN5促进LDs脂解及利用，改善脂代谢紊乱”的科学假设。为验证该假设，本课题首先在动物和细胞水平研究SFN对PLIN5磷酸化及核转位的影响及调控机制；随后采用plin5过表达/沉默的动物和细胞模型及磷酸化PLIN5正反突变体，明确PLIN5在SFN促进LDs脂解和产物利用中的作用机制；最后开展SFN对单纯性脂肪肝患者的干预研究评估其改善效果。本课题将从人群、器官、细胞、分子水平，为代谢性疾病的营养防控提供新思路和靶点，具有重要的理论意义和应用价值。

Lipid droplets (LDs) is an organelle for lipids storage. When the metabolic pressure is overloaded due to long-term excess energy or nutrition, the abnormal accumulation of LDs will produce lipo-toxicity, which may lead to a variety of metabolic disorders. Sulforaphane (SFN), rich in broccoli, could attenuate the excessive accumulation of LDs, while its underling mechanisms are unclear. We previously found that SFN decreased the expression of PLIN5 in cytoplasm, which may be related to its translocation into the nucleus after phosphyraltion. Also SFN upregulated the lipolysis enzymes of LDs and enhanced biosynthesis of mitochondria. We therefore hypothesize that SFN improves the disorders of lipid metabolism through the degradation of LDs and utilization of it products by phosphyralating PLIN5. To verify this hypothesis, the effect of SFN on the phospharylation and nuclear translocation of PLIN5 protein will be firstly determined both in vivo and in vitro. Secondly, the underling mechanisms by which SFN induces LDs degradation and utilization will be further clarified in the models of plin5-/-mice, plin5-/- and plin5+/+ HHL-5cell, as well as negative and positive mutant of PLIN5 phospharylation-induced HHL-5 cell. At last, an interventional trial based on the patients with non-alcohol fatty liver disease will be performed using the broccoli extract. All together, we, maybe for the first time, try to clarify the molecular mechanism of LDs degradation by SFN from the levels of population, organ, cell and molecule. Also the project provides the novel idea and target for preventing the abnormal lipid metabolism from the perspective of nutrition which has important theoretical significance and application value.