Ouro Alberto, Arana Lide, Riazy Maziar, Zhang Peng, Gomez-Larrauri Ana, Steinbrecher Urs, Duronio Vincent, Gomez-Muñoz Antonio
Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), 48080 Bilbao, Spain.
Department of Medicine. University of British Columbia and Vancouver Coastal Health Research Institute, Vancouver, British Columbia, Canada.
Exp Cell Res. 2017 Dec 15;361(2):277-283. doi: 10.1016/j.yexcr.2017.10.027. Epub 2017 Oct 31.
The bioactive sphingolipid ceramide 1-phosphate (C1P) regulates cell division in a variety of cell types including macrophages. However, the mechanisms involved in this action are not completely understood. In the present work we show that C1P stimulates the release of vascular endothelial growth factor (VEGF) in RAW264.7 macrophages, and that this growth factor is essential for stimulation of cell proliferation by C1P. The stimulation of VEGF release was dependent upon activation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB-1 also known as Akt-1), and mitogen-activated protein kinase-kinase (MEK)/extracellularly regulated kinase-2 (ERK-2) pathways, as inhibition of these kinases with selective pharmacological inhibitors or with specific gene silencing siRNA, abrogated VEGF release. A key observation was that sequestration of VEGF with a neutralizing antibody, or treatment with VEGF siRNA abolished C1P-stimulated macrophage growth. Also, inhibition of the pathways involved in C1P-stimulated VEGF release inhibited the stimulation of macrophage growth by C1P. Moreover, blockade of VEGF receptor-2 (VEGFR-2), which is the primary receptor for VEGF, with the pharmacological inhibitor DMH4, or with specific VEGFR-2 siRNA, substantially inhibited C1P-stimulated cell growth. It can be concluded that stimulation of VEGF release is a key factor in the promotion of macrophage proliferation by C1P.
生物活性鞘脂神经酰胺 1-磷酸（C1P）在包括巨噬细胞在内的多种细胞类型中调节细胞分裂。然而，这一作用所涉及的机制尚未完全明确。在本研究中，我们发现 C1P 可刺激 RAW264.7 巨噬细胞释放血管内皮生长因子（VEGF），且该生长因子对于 C1P 刺激细胞增殖至关重要。VEGF 释放的刺激依赖于磷脂酰肌醇 3-激酶（PI3K）/蛋白激酶 B（PKB - 1，也称为 Akt - 1）以及丝裂原活化蛋白激酶激酶（MEK）/细胞外调节激酶 - 2（ERK - 2）信号通路的激活，因为用选择性药理抑制剂或特异性基因沉默 siRNA 抑制这些激酶会消除 VEGF 的释放。一个关键的观察结果是，用中和抗体隔离 VEGF 或用 VEGF siRNA 处理可消除 C1P 刺激的巨噬细胞生长。此外，抑制参与 C1P 刺激 VEGF 释放的信号通路会抑制 C1P 对巨噬细胞生长的刺激。而且，用药理抑制剂 DMH4 或特异性 VEGFR - 2 siRNA 阻断 VEGF 的主要受体 VEGF 受体 - 2（VEGFR - 2），可显著抑制 C1P 刺激的细胞生长。可以得出结论，刺激 VEGF 释放是 C1P 促进巨噬细胞增殖的关键因素。
