FGF21对肝细胞脂代谢的调控研究

发布时间：2018-01-01 22:04

本文关键词：FGF21对肝细胞脂代谢的调控研究　出处：《华中农业大学》2011年硕士论文　论文类型：学位论文

更多相关文章： FGF21 SREBP1c 肝细胞脂代谢

【摘要】：肝脏脂肪过度积累会导致肝脏脂肪变性,脂肪肝,肝癌等一系列肝脏疾病。FGF21是近几年发现的对脂代谢疾病有重要作用的细胞因子,其在肝脏中表达丰度很高,本文利用HepG2细胞系作为肝细胞模型,通过油红O染色确定了FGF21超表达对肝细胞甘油三酯积累的影响,分析了其超表达对肝细胞中糖脂代谢相关基因的转录表达水平的调控,并通过Western Blot和Real-time PCR方法进一步分析了过量表达的FGF21对调节脂肪酸合成的关键转录因子SREBP1c的表达、加工的影响；最后借助双荧光素酶报告基因检测系统分析了SREBP-1c对FGF21启动子转录活性的影响。研究结果证明FGF21通过抑制SREBP1c的表达和加工成熟过程,从而减少SREBP1c靶基因即脂肪酸合成相关基因的转录,最后达到减少肝细胞甘油三酯积累的目的。另外本文还克隆猪FGF21基因,并对其进行组织表达分析；原核表达并初步纯化该基因的蛋白质,以猪为模型,为研究该基因的功能提供基础平台。以下为本文的具体研究结果： 1.FGF21抑制肝细胞的脂肪酸合成过程,但不影响脂肪酸的吸收和VLDL的组装,进而使肝细胞内的甘油三酯积累减少；FGF21也能够挽救由高浓度脂肪酸引起的SREBP-1c和FAS表达量的增加；FGF21抑制SREBP-1c基因的转录和蛋白质的加工及入核；SREBP-1c能够抑制FGF21的启动子活性,形成一个反馈抑制的调节环路；最后FGF21抑制肝细胞的脂肪酸氧化及线粒体的生物合成。另外葡萄糖和ChREBP能够上调FGF21 mRNA的表达水平,而游离脂肪酸和S(?)REBP-1c则抑制FGF21的转录表达。 2.FGF21在糖代谢中几乎不发挥作用。只是在基础条件下抑制糖异生的关键酶PEPCK基因的转录。 3.获得猪FGF21全编码区627 bp,共编码208个氨基酸；该基因包含3个外显子和2个内含子,其基因组结构及各个外显子长度与人和小鼠FGF21的基因组结构相似；FGF21在猪各组织中广泛表达,其中在肝脏,各脂肪组织(包括肠系膜脂肪组织,附睾脂肪组织和皮下脂肪组织)及肾脏等代谢器官中表达量较高。
[Abstract]:Liver fat excessive accumulation can lead to hepatic steatosis, fatty liver, liver cancer and liver disease is a series of.FGF21 cytokines found in recent years and plays an important role in lipid metabolism in the liver disease, the expression level is very high, this paper use HepG2 cells as liver cell model was determined by oil red O staining effects of FGF21 overexpression on the accumulation of hepatic triglycerides, analyzed its over expression of transcription on glucose and lipid metabolism related genes in liver cells can regulate the expression of Blot and Real-time, and the Western PCR method for further analysis of the excessive expression of FGF21 expression on the regulation of fatty acid synthesis of the key transcription factor SREBP1c, the influence of processing; finally using the dual luciferase reporter assay system to analysis the influence of SREBP-1c on the transcription activity of FGF21 promoter. The results show that FGF21 inhibit the expression of SREBP1c and Mature industry process, thereby reducing the SREBP1c target gene transcription of genes related to fatty acid synthesis, finally to reduce the accumulation of liver triglyceride. We also cloned the porcine FGF21 gene and its tissue expression analysis; prokaryotic expression of the gene and protein purification in a porcine model, provide a basic platform for study on the function of the gene. The following is the specific research results in this paper:
Fatty acid synthesis process of 1.FGF21 inhibition of liver cells, but does not affect the assembly and absorption of VLDL fatty acids, and the liver cells reduce the accumulation of triglycerides; FGF21 can also save caused by high concentration of fatty acids of SREBP-1c and the increase of FAS expression; FGF21 inhibits transcription and processing of protein and nuclear SREBP-1c gene; SREBP-1c can inhibit FGF21 promoter activity, the formation of a feedback inhibition regulation loop; finally FGF21 inhibit hepatocyte fatty acid oxidation and mitochondrial biogenesis. In addition of glucose and ChREBP can up regulate the expression of FGF21 and mRNA, free fatty acids and S (?) FGF21 inhibited the transcriptional expression of REBP-1c.
2.FGF21 does not play a role in sugar metabolism. It only inhibits the transcription of the key enzyme, the key enzyme, PEPCK gene, under the basic conditions.
3. porcine FGF21 encoding region of 627 BP, encoding 208 amino acids; the gene contains 3 exons and 2 introns, its genome structure and each exon genomic structure and length of human and mouse are similar to that of FGF21; FGF21 is widely expressed in tissues of pigs, especially in liver, fat the organization (including mesenteric adipose tissue, epididymal adipose tissue and subcutaneous adipose tissue) high expression and kidney metabolic organ.

【学位授予单位】：华中农业大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：R363

【共引文献】