PGC1α协同PPARγ调节CIDEC基因在小鼠脂肪细胞系中表达

PGC1α synergizes PPARγ to regulate transcription of CIDEC in mouse adipocyte

目的鉴定CIDEC的表达能够被PPARγ和PGC1α共激活,检测其在脂肪代谢中的重要调控作用。方法构建5′删切和顺式原件突变的启动子,运用HepG2细胞中双荧光报告基因实验检测PPARγ和PGC1α对CIDEC的共激活作用并确定顺式作用元件。运用PPARγ特异激动剂pioglitazone刺激3T3-L1细胞检测CIDEC的mRNA水平。在3T3-L1细胞系中过表达CIDEC,检测脂肪合成及能量代谢相关基因的mRNA水平。通过腺病毒感染在小鼠肝原代细胞中过表达CIDEC,检测肝脏细胞中脂肪变化。结果 PPARγ和PGC1α能够显著激活CIDEC的启动子。过表达CIDEC后,脂肪细胞中脂类合成相关基因FAS上调(3.47±0.17)倍(P<0.05),ACC上调(3.95±0.57)倍(P<0.05),在肝原代细胞中CIDEC促进脂滴的生成。结论 CIDEC过表达能够被PPARγ促进并且被PGC1α共激活,在体内起到促进脂肪积累的作用。

Objective To identify the regulation of PPARγ and PGC1α on CIDEC transcription and the function of CIDEC in adipose metabolism.Methods Reconstructe CIDEC promoter reporters including a series of 5′-deletions and cis-element mutations.Dual-luciferase assay was performed to screen PPARγ binding sites in HepG2 cells.Pioglitazone,the PPARγ agonist,was used in 3T3-L1 cells to detect the CIDEC mRNA level.Adenoviral CIDEC was constructed and over-expressed CIDEC gene through adenovirus in primary hepatocytes to examine the effect of CIDEC on liver adipose metabolism.Results PPARγ and PGC1α can stimulate CIDEC transcription obviously.Over-expressing CIDEC stimulate gene FAS 3.47±0.17（P0.05） and ACC 3.95±0.57（P0.05）,and adipose synthesis in hepatocytes.Conclusion Transcription of CIDEC can be activated by PPARγ and its coactivitor PGC1α.This activation results in accumulation of fat in liver cells.