瘦素对Hep G2细胞瘦素受体mRNA表达的影响(英文)

Effect of leptin on expressions of leptin receptors mRNA in HepG2 cells

摘要:

目的 瘦素抵抗被认为是单纯性肥胖儿童的主要发病机制。瘦素受体水平及其下游信号通路可能与瘦素抵抗有关。本实验研究瘦素对瘦素受体基因表达的影响 ,探讨瘦素抵抗的发生机制。方法 以HepG2细胞株为实验模型 ,利用细胞培养、DNA序列测定及半定量的RT PCR等方法 ,检测不同浓度 (0 ,10 -9,10 -8,10 -7,10 -6M )的瘦素对HepG2细胞瘦素短型受体 (OB Ra :OB R2 19.1,OB R2 19.3)及长型受体 (OB Rb)mRNA的表达的影响。结果 HepG2细胞含有OB Ra及OB Rb。当HepG2细胞与不同浓度的瘦素培养 2 4h后 ,10 -7-10 -6M浓度瘦素明显抑制了OB Rb的mRNA表达 ,并在 10 -6M浓度时作用最强 (0 .4 3± 0 .14vs 1.0 1± 0 .2 2 )。10 -8～ 10 -6M浓度的瘦素亦明显抑制了OB R2 19.1及OB R2 19.3的mRNA表达 ,并在 10 -7和 10 -6M浓度时分别达到最大抑制 ,为不含瘦素对照组的 4 4 %和 4 9%。结论 瘦素对HepG2细胞瘦素受体表达有下调作用 ,这可能是体内瘦素抵抗的机制之一。

Abstract:

Objective Leptin resistance is thought to be a main mechanism of human obesity. Although some studies suggested that leptin resistance could be relevant to the level of leptin receptor and its downstream signaling pathway, there has been little research on leptin receptor regulation. This paper studied the effect of leptin on its receptors. Methods The human hepatocellur carcinoma cell line HepG 2 was incubated in serum-free medium containing 0, 10 -9, 10 -8, 10 -7, 10 -6 M of human leptin respectively for 24 hrs. Then semi-quantitative RT-PCR was used to measure the changes of long (OB-Rb) and short (OB-Ra: OB-R219.1, OB-R219.3) leptin receptors mRNA expressions in HepG2 cells. Results Both OB-Ra and OB-Rb mRNA were expressed in HepG2 cells, which provided a useful model for studies of leptin receptors regulation. Leptin (10 -7-10 -6 M) induced a significant decrease in the OB-Rb mRNA expression, with the maximum effect at 10 -6 M( 0.43± 0.14 vs 1.01± 0.22), when compared with the control (incubation in the absence of leptin). Similarly, the expressions of OB-R219.1 and OB-R219.3, two isoforms of OB-Ra, were also markedly reduced in cells treated with 10 -8-10 -6 M leptin, with the maximum inhibition for OB-R219.1 at 10 -7 M (44% of the control) and for OB-R219.3 at 10 -6 M (49% of the control). Conclusions Leptin can inhibit the expressions of both OB-Ra and OB-Rb mRNA in HepG2 cells, which may be associated with leptin resistance in vivo.