去泛素化酶YOD1调控肝脏脂代谢的初步研究

Study on YOD1 in regulating liver lipid metabolism

目的:探索去泛素化酶YOD1在肝脏营养代谢中发挥的作用。方法:通过Q-PCR检测高脂饮食C57BL/6小鼠、db/db小鼠肝脏中以及油酸(oleic acid,OA)处理后的Hepa1-6细胞内,YOD1的表达情况。在C57BL/6小鼠中,通过Q-PCR法检测YOD1的组织分布及不同营养状态下的表达情况。对Hepa1-6细胞中给予OA处理,通过甘油三酯试剂盒检测细胞内甘油三脂含量,并利用油红染色观察细胞内脂滴。经Q-PCR和蛋白免疫印迹法检测细胞内相关基因的m RNA及蛋白水平。结果:短期高脂饮食后,肝脏中YOD1的mRNA水平显著下降。而与对照组db/+小鼠相比,db/db小鼠肝脏中YOD1的mRNA水平无变化。但是,经OA处理后,Hepa1-6细胞内的YOD1的mRNA水平明显减少。另外,YOD1主要表达于肝脏中。小鼠禁食后,肝脏YOD1的mRNA水平显著增加,而再喂食后显著下降。此外,过表达YOD1的Hepa1-6细胞中OA诱导的脂质堆积明显减少,且SREBP-1c的剪切被抑制。结论:本研究初步发现,去泛素化酶YOD1的表达水平受营养状态调控,并通过抑制SREBP-1c的剪切影响肝细胞的脂代谢。

Objective:This study aims to explore the role of deubiquitinating enzyme YOD1 in liver nutrient metabolism.Methods:The expression of YOD1 in the liver of HFD-fed C57 BL/6 mice,db/db mice and in Hepa1-6 cells after oleic acid(OA)treatment was checked by Q-PCR.Then its tissue distribution in C57 BL/6 mice and its expression under different nutritional conditions was detected by Q-PCR.The content of triglycerides in Hepa1-6 cells treated with OA was determined by TAG enzymetic kit,and lipid droplets were observed by Oil Red O staining.Moreover,the mRNA and protein levels of related genes in cells were detected by Q-PCR and Western blot.Results:After a short-term HFD-fed,the mRNA level of YOD1 in the liver decreased significantly.But compared with that of db/+mice in control group,the expression of YOD1 was no change in db/db mice.However,its expression reduced obviously in OAtreated Hepa1-6 cells.Besides,YOD1 was mainly distributed in the liver,and we observed that fasting led to increased mRNA level of YOD1 in mice liver while YOD1 decreased notably after refeeding.Further,YOD1 overexpression remarkably ameliorated OA-induced steatosis in Hepa1-6 cells by inhibiting SREBP-1 c cleavage.Conclusion:YOD1 expression is regulated by nutritional status and modulates lipid metabolism in hepatocytes by inhibiting SREBP-1 c cleavage.