IGF-I stimulates human intestinal smooth muscle cell growth by regulation of G1 phase cell cycle proteins
IGF-I stimulates human intestinal smooth muscle cell growth by regulation of G1 phase cell cycle proteins
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DOI：
10.1152/ajpgi.00403.2003
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发表时间：
2004-03-01
影响因子：
4.5
通讯作者：
Bowers, JG
中科院分区：
文献类型：
--
作者：
Kuemmerle, JF;Zhou, HP;Bowers, JG
胰岛素样生长因子-I (IGF-I) 的自分泌产生通过激活不同的磷脂酰肌醇 3-激酶 (PI3-激酶) 依赖性和 ERK1/2 依赖性途径来调节人肠肌细胞的生长。本研究的目的是确定 IGF-I 调节细胞周期 G(1) 期和肌肉细胞增殖的机制。通过使用荧光激活细胞分选分析和掺入 [H-3] 胸苷来测量静止细胞与 IGF-I 的孵育刺激时间依赖性细胞周期进程。使用基于微阵列的方法的研究最初用于鉴定人类肠肌中表达的基因，编码已知参与受IGF-I调节的细胞周期G(1)期的蛋白质。将肌肉细胞与 IGF-I 一起孵育 24 小时，导致细胞周期蛋白 D1 的表达增加超过五倍，视网膜母细胞瘤蛋白 (Rb1) 的表达增加超过两倍。 IGF-I 引起细胞周期蛋白 D1 蛋白水平的时间依赖性增加，这是由 ERK1/2 依赖性和 PI3 激酶依赖性机制共同介导的。细胞周期蛋白 D1 水平的增加伴随着细胞周期蛋白 D1 依赖性激酶 4 (CDK4) 活性的时间依赖性增加。 IGF-I 还引起 Rb-(Ser807/811) 磷酸化（细胞周期蛋白 D-1 依赖性 CDK4 激酶的特定靶标）的快速时间依赖性增加，以及总 Rb 蛋白水平的缓慢增加。我们得出结论，IGF-I 刺激人肠平滑肌细胞的 G(1) 期进展、DNA 合成和细胞增殖。 IGF-I 对增殖的影响由 ERK1/2 依赖性和 PI3 激酶依赖性途径共同介导，调节细胞周期蛋白 D1 水平、CDK4 活性和 Rb 活性。
Autocrine production of insulin-like growth factor-I (IGF-I) regulates growth of human intestinal muscle cells by activation of distinct phosphatidylinositol 3-kinase (PI3-kinase)- dependent and ERK1/2-dependent pathways. The aim of the present study was to determine the mechanisms by which IGF-I regulates the G(1) phase of the cell cycle and muscle cell proliferation. Incubation of quiescent cells with IGF-I stimulated time-dependent cell cycle progression measured by using fluorescence-activated cell sorting analysis and by incorporation of [H-3] thymidine. Studies using a microarray- based approach were used initially to identify genes expressed in human intestinal muscle encoding proteins known to participate in the G(1) phase of the cell cycle that were regulated by IGF-I. Incubation of muscle cells for 24 h with IGF-I elicited greater than fivefold increase in the expression of cyclin D1 and greater than twofold increase in retinoblastoma protein (Rb1). IGF-I elicited a time-dependent increase in cyclin D1 protein levels mediated jointly by ERK1/2-dependent and PI3-kinase-dependent mechanisms. Increase in cyclin D1 levels was accompanied by a time-dependent increase in cyclin D1-dependent cyclin-dependent kinase-4 (CDK4) activity. IGF-I also elicited a rapid time-dependent increase in Rb-(Ser807/811) phosphorylation, the specific target of the cyclin D-1-dependent CDK4 kinase, and a slower increase in total Rb protein levels. We conclude that IGF-I stimulates G(1) phase progression, DNA synthesis, and cell proliferation of human intestinal smooth muscle cells. Effects of IGF-I on proliferation are mediated jointly by ERK1/2-dependent and PI3-kinase-dependent pathways that regulate cyclin D1 levels, CDK4 activity, and Rb activity.