Human aortic smooth muscle cells are insulin resistant at the receptor level but sensitive to IGF1 and IGF2
Human aortic smooth muscle cells are insulin resistant at the receptor level but sensitive to IGF1 and IGF2
复制标题
DOI：
10.1677/jme-09-0021
复制
发表时间：
2009-11-01
影响因子：
3.5
通讯作者：
Arnqvist, H. J.
中科院分区：
文献类型：
--
作者：
Chisalita, S. I.;Johansson, G. S.;Arnqvist, H. J.
生理浓度的胰岛素是否对血管平滑肌细胞（VSMC）有直接影响仍存在争议。我们的目的是表征 VSMC 中胰岛素抵抗的机制。为了进行比较，还研究了 IGF1 和 IGF2 的作用。使用培养的人主动脉平滑肌细胞（HASMC）。通过定量逆转录 PCR 分析受体 mRNA，通过 ELISA 和蛋白质印迹分析受体蛋白。通过胸苷掺入和葡萄糖积累来研究生物学效应。在 HASMC 中，IGF1 受体 (IGF1 R) 的 mRNA 和蛋白表达比胰岛素受体 (IR) 高五倍。 IR 同工型 A mRNA 的表达量是 IR 同工型 B 的 13 倍。IR 和 IGF1R 共沉淀，表明存在杂合 IR/IGF1R。 IGF1Rβ亚基的磷酸化通过IGF1 10(-9)-10(-8) mol/l和IGF2 10(-8) mol/l获得。 IRβ亚基被IGF1 10(-8) mol/l磷酸化，但不被胰岛素磷酸化。 IGF1分别以10(-8) mol/l刺激IR底物-1和AKT，以10(-9)-10(-8) mol/l刺激细胞外信号调节激酶1和2。浓度为10(-8)-10(-7) mol/l的IGF1和2显着刺激H-3-胸苷掺入，而胰岛素则没有。 C-14-葡萄糖积累受到IGF1或IGF2 10(-8)-10(-7) mol/l以及胰岛素10(-7) mol/l的刺激。我们的结果表明，IGF1R 和杂合 IR/IGF1R 被 HASMC 中生理浓度的 IGF1 和 2 激活，这会传播下游信号传导和生物效应，而胰岛素对其受体或下游信号传导没有影响，可能是由于 IGF1R 占优势以及 IR 掺入杂合 IR/IGF1R 中。
Whether insulin, at physiological concentrations, has direct effects on vascular smooth muscle cells (VSMCs) remains controversial. Our aim was to characterize the mechanism for insulin resistance in VSMCs. For comparison, the effects of IGF1 and IGF2 were also studied. Cultured human aortic smooth muscle cells (HASMC) were used. Receptor mRNA was analyzed by quantitative reverse transcription PCR and receptor protein by ELISA and western blot. Biological effects were studied by thymidine incorporation and glucose accumulation. In HASMC, both mRNA and protein expression of IGF1 receptors (IGF1 R) were fivefold higher compared to insulin receptor (IR). IR isoform A mRNA was 13-fold more expressed than IR isoform B. IR and IGF1R co-precipitated, indicating the presence of hybrid IR/IGF1R. Phosphorylation of the IGF1R beta-subunit was obtained by IGF1 10(-9)-10(-8) mol/l and IGF2 10(-8) mol/l. IR beta-subunit was phosphorylated by IGF1 10(-8) mol/l but not by insulin. IGF1 stimulated IR substrate-1 and AKT at 10(-8) mol/l and extracellular signal-regulated kinases 1 and 2 at 10(-9)-10(-8) mol/l respectively. IGF1 and 2 at a concentration of 10(-8)-10(-7) mol/l significantly stimulated H-3-thymidine incorporation, whereas insulin did not. C-14-Glucose accumulation was stimulated by IGF1 or IGF2 10(-8)-10(-7) mol/l, and also by insulin 10(-7) mol/l. Our results suggest that IGF1R and hybrid IR/IGF1R are activated by physiological concentrations of IGF1 and 2 in HASMC and this propagates downstream signaling and biological effects, while insulin has no effect on its receptor or downstream signaling probably due to a preponderance of IGF1R and incorporation of IR into hybrid IR/IGF1R.