Expression and function of receptors for insulin-like growth factor-I and insulin in human coronary artery smooth muscle cells
Expression and function of receptors for insulin-like growth factor-I and insulin in human coronary artery smooth muscle cells
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DOI：
10.1007/s00125-005-1890-4
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发表时间：
2005-10-01
期刊：
影响因子：
8.2
通讯作者：
Arnqvist, HJ
中科院分区：
文献类型：
--
作者：
Chisalita, SI;Arnqvist, HJ
目的/假设：高胰岛素血症和胰岛素抵抗以及低IGF-I与心血管疾病的发病机制有关。胰岛素样生长因子-I和胰岛素对人冠状动脉平滑肌细胞（HCASMCs）的直接作用知之甚少。本研究旨在探讨胰岛素样生长因子-I受体（IGF-IR）和胰岛素受体（IR）在HCASMCs中的表达及功能。材料和方法：采用体外培养的HCASMCs。通过定量实时RT-PCR分析测量mRNA表达。受体蛋白，磷酸化的β-亚基和杂交IR/IGF-IR的存在进行了分析，通过免疫沉淀和蛋白质印迹。DNA合成和葡萄糖代谢分别采用[H-3]胸苷掺入和D-[U-C-14]葡萄糖蓄积进行评估。结果：HCASMC中IGF-IR mRNA的表达约为IR mRNA表达的8倍。免疫沉淀和免疫印迹分析可证实IGF-IR和IR的存在。IGF-IR β亚基的磷酸化通过10（-10）-10（-8）mol/l的IGF-I和10（-8）mol/l的胰岛素获得。10（-10）~ 10（-9）mol/l的胰岛素和IGF-I使IR β亚基磷酸化。当用单克隆抗IR α亚基或IGF-IR α亚基抗体进行免疫沉淀时，我们发现条带的位置略有不同，IGF-I在10（-9）-10（-8）mol/l时显著刺激[H-3]胸苷掺入，在10（-9）-10（-7）mol/l时也刺激D-[U-C-14]掺入。HCASMC中的葡萄糖积聚。10- 9 ~ 10- 7 mol/ l的胰岛素对DNA合成无影响，但在10（-7）mol/l时增加葡萄糖积累。结论/解释：我们的研究提供了实验证据，IGF-IR和可能的混合IR/IGF-IR在HCASMC中发挥作用。
Aims/hypothesis: Hyperinsulinaemia and insulin resistance, as well as low IGF-I, have been implicated in the pathogenesis of cardiovascular disease. Little is known about direct effects of IGF-I and insulin on human coronary artery smooth muscle cells (HCASMCs). Our aim was to characterise the expression and function of IGF-I receptor (IGF-IR) and insulin receptor (IR) in HCASMCs. Materials and methods: Cultured HCASMCs were used. mRNA expression was measured by quantitative real-time RT-PCR analysis. Receptor proteins, phosphorylation of beta-subunits and the presence of hybrid IR/IGF-IR were analysed by immunoprecipitation and western blotting. DNA synthesis and glucose metabolism were assessed using [H-3] thymidine incorporation and D-[U-C-14] glucose accumulation respectively. Results: The mRNA expression of IGF-IR was approximately eight-fold higher than that of IR in HCASMCs. The presence of IGF-IR and IR could be demonstrated by immunoprecipitation and western blot analysis. Phosphorylation of the IGF-IR beta-subunit was obtained by IGF-I at 10(-10) - 10(-8) mol/l and insulin at 10(-8) mol/l. Insulin and IGF-I at 10(-10) - 10(-9) mol/l phosphorylated the IR beta-subunit. When immunoprecipitated with monoclonal anti-IR alpha-subunit or IGF-IR alpha-subunit antibodies, we found bands in slightly different positions, suggesting the presence of hybrid IR/IGF-IR. IGF-I at 10(-9) - 10(-8) mol/l significantly stimulated [H-3] thymidine incorporation and at a concentration of 10(-9) - 10(-7) mol/l also D-[U-C-14] glucose accumulation in HCASMCs. Insulin at 10- 9 - 10- 7 mol/ l had no effect on DNA synthesis, but increased glucose accumulation at 10(-7) mol/l. Conclusions/ interpretation: Our study provides experimental evidence that IGF-IR and possibly hybrid IR/IGF-IR play a role in HCASMCs.