缺氧诱导因子1α(HIF1α)下调HepG2细胞中甘氨酸-N-甲基转移酶(GNMT)基因的表达

Hypoxia inducible factor 1 alpha(HIF1α)down regulate glycine-N-methyltransferase(GNMT) gene in HepG2 cells

目的 探讨乏氧对甘氨酸-N-甲基转移酶（Glycine-N- methyltransferase,GNMT）表达的影响,以及GNMT与缺氧诱导因子1α （hypoxia inducible factor 1 alpha,HIF1α）表达之间的关系。方法 HepG2,293T,H460 3株细胞常规培养并设立常氧组和乏氧组,待细胞生长至50%~60%融合后,将乏氧组细胞放入1%氧气乏氧箱继续培养24 h,常氧组继续常规培养24 h后,运用半定量PCR,实时荧光定量PCR方法分析HepG2,293T,H460 3株细胞乏氧后相对于常氧GNMT基因的表达变化;通过小RNA干扰方法敲低HepG2细胞中HIF1α基因和HIF2A基因,运用实时荧光定量技术检测干扰效率,并检测GNMT基因的表达变化。结果 乏氧能够下调HepG2,293T,H460 3株细胞中GNMT基因的表达,HepG2细胞中抑制最明显;3株细胞的GNMT基因表达抑制率分别为68%,17%,21%;在HepG2细胞中敲低HIF1α基因能够引起GNMT表达明显上调,而敲低HIF2A后GNMT表达无明显变化。结论 在HepG2细胞中乏氧可能通过HIF1α下调GNMT的表达。

Objective To explore the changing of glycine-N-methyltransferase （GNMT） gene expression during hypoxia,and the relationship between GNMT and hypoxia inducible factor 1 alpha （HIF1α）. Methods The HepG2,293T,H460 cell lines were cultured and divided into two groups：hpoxia goup and normal group.After grown to 50% to 60% confluence,the hyoxia group cells were incubated at 1%O2 for 24 hours,and the nomal group cells were cultrued nomally for 24 hours.Then,the alteration of the hypoxia group＆prime;s GNMT gene expression compared with the nomal group were observed by RT-PCR and realtime PCR;HIF1A gene and HIF2A gene were knock down by small interfering RNA （siRNA） in HepG2 cells,transfection efficiency and GNMT gene expression were detected by realtime PCR. Results Hypoxia down regulate GNMT gene expression in three cell lines,especially in HepG2 cells.The inhibitory rate of HepG2,293T,H460 cells was 68%,17%,21%.HIF1A knockdown led to significant increased expression of GNMT gene in HepG2 cells,howeverHIF2A knockdown can＆prime;t. Conclusions Hpoxia down regulate GNMT gene expression in a HIF1α dependent way in HepG2 cells.