胰岛素样生长因子-1对血管平滑肌细胞磷酸酶PHLPP蛋白表达的影响

Effect of insulin like growth factor-1 on the expression of phosphatase PHLPP in vascular smooth muscle cells

目的:探讨胰岛素样生长因子-1(IGF-1)及氧化低密度脂蛋白(oxLDL)促血管平滑肌细胞(VSMC)增殖的细胞内信号转导机制。方法:体外培养的兔血管平滑肌细胞分3组处理,以细胞计数、噻唑盐比色法测定细胞增殖能力,Western Blot定量磷酸酶PHLPP蛋白表达水平。结果:IGF-1(100μg/L)使VSMC计数及MTT比色A值分别增至对照组的3.02倍及3.06倍。oxLDL(50μg/mL)使上述两值分别增至对照组的2.03倍及2.91倍。两者均可以显著抑制PHLPP蛋白表达水平。结论:IGF-1及oxLDL的促VSMC增殖作用可能与抑制PHLPP蛋白的负性调节细胞生长作用有关。

Objective To investigate the intracellular signal transduction pathway of the proliferation of vascular smooth muscle cells （VSMCs） stimulated by insulin-like growth factor-1 （IGF-1） and oxidized low density lipoprotein （oxLDL）. Methods Rabbit aortic VSMCs were cultured in vitro and divided into 3 groups. Proliferating ability of the cells was determined by cell number measuring and mitochondrial dehydrogenase （MD） activity （MTT assay）. Western blot was used to detect the expression of phosphatase PHLPP protein. Results Number of VSMCs was increased to 3.02 or 2.03 times,while MD activity was increased to 3.06 or 2.91 times of control group after treated with 100 μg / L of IGF-1 or 50 μg / mL of oxLDL. Both of IGF-1 and oxLDL can inhibit the expression of PHLPP protein. Conclusion The promoting effects of IGF-1 and oxLDL on VSMCs proliferation may possibly be through inhibiting the expression of phosphatase PHLPP protein.