Objective

The direct actions of growth hormone (GH) in the development of atherosclerosis are unclear. The goal of this study was to characterize GH-induced changes in expression of signaling pathway elements and other proteins that may be related to atherosclerosis.

Methods

Human umbilical vein endothelial cells (HUVEC) and THP-1, a human acute monocytic leukemia cell line, were stimulated by exposure to 10⁻⁹ M or 10⁻⁸ M human GH with or without pretreatment with a mitogen-activated protein kinase kinase (MEK) 1 inhibitor. Levels of transcripts encoding vascular cell adhesion molecule (VCAM) -1, E-selectin, monocyte chemotactic protein (MCP-1), interleukin (IL) -6, and IL-8 were investigated by reverse transcription (RT) -PCR. For the quantitative adhesion assay, THP-1 cells or human primary monocytes were fluorescently labeled with 3’-O-acetyl-2′,7′-bis(carboxyethyl) -4 diacetoxymethyl ester (BCECF/AM). HUVEC treated with human GH were co-incubated with BCECF-labeled THP-1 cells. One hour later, the number of BCECF-labeled THP-1 cells was assessed. An equivalent experiment was performed using BCECF-labeled primary monocytes, and the number of monocytes adhering to HUVEC was counted.

Results

Treatment with hGH increased the levels of E-selectin- and VCAM-1-encoding mRNAs in HUVEC. This effect was attenuated by pretreatment with a MEK1 inhibitor. Furthermore, hGH treatment increased adhesion of BCECF-labeled THP-1 cells or primary monocytes to HUVEC, and this effect was attenuated by pretreatment with a MEK1 inhibitor.

Conclusions

VCAM-1 and E-selectin expression was stimulated by GH via the mitogen-activated protein kinase pathway, resulting in augmented adhesion of THP-1 cells and monocytes to HUVEC. These data suggested that GH directly stimulates the development of atherosclerosis.

中文翻译：

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生长激素信号通路在动脉粥样硬化发展中的作用。

客观的

生长激素 (GH) 在动脉粥样硬化发展中的直接作用尚不清楚。本研究的目的是表征 GH 诱导的信号通路元件和其他可能与动脉粥样硬化有关的蛋白质表达的变化。

方法

人脐静脉内皮细胞 (HUVEC) 和人急性单核细胞白血病细胞系 THP-1 通过暴露于 10 ^-9  M 或 10 ^-8  M 人 GH刺激，有或没有用丝裂原活化蛋白激酶激酶预处理。 MEK) 1 抑制剂。通过逆转录(RT)-PCR研究编码血管细胞粘附分子(VCAM) -1、E-选择蛋白、单核细胞趋化蛋白(MCP-1)、白介素(IL) -6和IL-8的转录物的水平。对于定量粘附测定，THP-1 细胞或人原代单核细胞用 3'- O荧光标记-乙酰基-2',7'-双（羧乙基）-4 二乙酰氧基甲酯（BCECF/AM）。用人 GH 处理的 HUVEC 与 BCECF 标记的 THP-1 细胞共孵育。一小时后，评估了 BCECF 标记的 THP-1 细胞的数量。使用 BCECF 标记的原代单核细胞进行等效实验，并对粘附在 HUVEC 上的单核细胞数进行计数。

结果

用 hGH 处理增加了HUVEC中E-选择素和VCAM-1编码 mRNA 的水平。这种作用通过用 MEK1 抑制剂预处理减弱。此外，hGH 处理增加了 BCECF 标记的 THP-1 细胞或原代单核细胞对 HUVEC 的粘附，并且这种作用通过用 MEK1 抑制剂预处理减弱。

结论

VCAM-1和E-选择素的表达受 GH 通过丝裂原活化蛋白激酶途径刺激，导致 THP-1 细胞和单核细胞对 HUVEC 的粘附增强。这些数据表明GH直接刺激动脉粥样硬化的发展。