大鼠脂肪细胞分化过程中脂代谢相关基因转录表达时序的研究

Studies on expression orders of lipid metabolism-related genes during differentiation of rat adipocytes

对大鼠附睾和肾周脂肪组织分离的前体脂肪细胞原代培养,采用RT-PCR法分析脂代谢重要酶和转录因子基因在不同分化阶段转录表达的时序变化。结果显示,在前体脂肪细胞阶段,固醇调控元件结合蛋白(SREBP)-1c、碳水化合物反应元件结合蛋白(ChREBP)以及脂肪酸合成酶(FAS)、乙酰辅酶A羧化酶α(ACC1)、硬酯酰辅酶A去饱和酶(SCD)和激素敏感脂酶(HSL)基因均不转录表达;HSL mRNA在分化初期表达,中期表达水平最高,分化末期降低;SCD mRNA在分化中期表达,末期表达水平显著提高;分化初期FAS mRNA水平明显高于中期和末期;ACC1mRNA仅在末期表达;分化初期SREBP-1c mRNA水平较高,中期和末期显著下降;ChREBP mR-NA表达水平在分化末期稍高于中期,但差异不显著。表明,SREBP-1c mRNA的表达与脂肪细胞早期分化调控有关,分化成熟脂肪细胞的ChREBP mRNA表达可能与生脂基因的转录激活有关。

Preadipocytes isolated from adipose tissue of male SD rats were cultured and divided into 4 stages of differentiation including preadipocytes, early, middle and terminal differentiating adipocytes through the oil red O staining. Order changes of transcriptional expression of genes encoding lipid metabolic enzymes and transcription factors in various stages of differentiation were examined using RT-PCR. The mRNAs of sterol regulatory element binding protein （SREBP）-1c, carbohydrate responsive element binding protein （ChREBP）, acetyl-CoA carboxylase α（ACC1）, fatty acid synthase （FAS）, stearoyl-CoA desaturase（SCD）, and hormone sensitive lipase（HSL） were not expressed in rat preadipocytes. HSL mRNA began to express in early and reach to maximal level in middle differentiating adipocytes. SCD mRNA level was significantly higher in the middle differentiating adipocytes than that in terminal differentiating adipocytes. FAS mRNA level was lower in middle and terminal than that in early differentiating adipocytes, and ACC1 mRNA was expressed only in terminal stage. The results suggested that the expression of SREBP- 1c gene could be related with the early differentiation regulation of adipocyte, and mRNA levels of ChREBP coincide with the changes in the expression of lipogenic gene in late differentiated adipocytes.