Research Unit on Lipids and Atherosclerosis, "Sant Joan" University Hospital, Universitat Rovira i Virgili, IISPV, Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Disorders, Reus, Spain.
PLoS One. 2013 Nov 29;8(11):e81914. doi: 10.1371/journal.pone.0081914. eCollection 2013.
The migration and proliferation of vascular smooth muscle cells play crucial roles in the development of atherosclerotic lesions. This study examined the effects of fatty acid binding protein 4 (FABP4), an adipokine that is associated with cardiovascular risk, endothelial dysfunction and proinflammatory effects, on the migration and proliferation of human coronary artery smooth muscle cells (HCASMCs).
A DNA 5-bromo-2'-deoxy-uridine (BrdU) incorporation assay indicated that FABP4 significantly induced the dose-dependent proliferation of HCASMCs with a maximum stimulatory effect at 120 ng/ml (13% vs. unstimulated cells, p<0.05). An anti-FABP4 antibody (40 ng/ml) significantly inhibited the induced cell proliferation, demonstrating the specificity of the FABP4 proliferative effect. FABP4 significantly induced HCASMC migration in a dose-dependent manner with an initial effect at 60 ng/ml (12% vs. unstimulated cells, p<0.05). Time-course studies demonstrated that FABP4 significantly increased cell migration compared with unstimulated cells from 4 h (23%vs. 17%, p<0.05) to 12 h (74%vs. 59%, p<0.05). Pretreatment with LY-294002 (5 µM) and PD98059 (10 µM) blocked the FABP4-induced proliferation and migration of HCASMCs, suggesting the activation of a kinase pathway. On a molecular level, we observed an up-regulation of the MAPK pathway without activation of Akt. We found that FABP4 induced the active forms of the nuclear transcription factors c-jun and c-myc, which are regulated by MAPK cascades, and increased the expression of the downstream genes cyclin D1 and MMP2, CCL2, and fibulin 4 and 5, which are involved in cell cycle regulation and cell migration.
These findings indicate a direct effect of FABP4 on the migration and proliferation of HCASMCs, suggesting a role for this adipokine in vascular remodelling. Taken together, these results demonstrate that the FABP4-induced DNA synthesis and cell migration are mediated primarily through a MAPK-dependent pathway that activates the transcription factors c-jun and c-myc in HCASMCs.
血管平滑肌细胞的迁移和增殖在动脉粥样硬化病变的发展中起着关键作用。本研究探讨了脂肪细胞型脂肪酸结合蛋白 4（FABP4），一种与心血管风险、内皮功能障碍和促炎作用相关的脂肪因子，对人冠状动脉平滑肌细胞（HCASMC）迁移和增殖的影响。
DNA 5-溴-2'-脱氧尿苷（BrdU）掺入试验表明，FABP4 显著诱导 HCASMC 呈剂量依赖性增殖，在 120ng/ml 时达到最大刺激作用（与未刺激细胞相比，增加 13%，p<0.05）。抗 FABP4 抗体（40ng/ml）显著抑制诱导的细胞增殖，证明 FABP4 增殖作用具有特异性。FABP4 以剂量依赖性方式显著诱导 HCASMC 迁移，在 60ng/ml 时出现初始作用（与未刺激细胞相比，增加 12%，p<0.05）。时间进程研究表明，与未刺激细胞相比，FABP4 从 4 小时（增加 23%，p<0.05）到 12 小时（增加 74%，p<0.05）显著增加细胞迁移。LY-294002（5µM）和 PD98059（10µM）预处理阻断了 FABP4 诱导的 HCASMC 增殖和迁移，提示激酶途径的激活。在分子水平上，我们观察到 MAPK 途径的上调，而 Akt 没有被激活。我们发现，FABP4 诱导了核转录因子 c-jun 和 c-myc 的活性形式，它们受 MAPK 级联调节，并增加了下游基因 cyclin D1 和 MMP2、CCL2、以及纤维蛋白 4 和 5 的表达，这些基因参与细胞周期调节和细胞迁移。
这些发现表明 FABP4 对 HCASMC 的迁移和增殖有直接影响，提示这种脂肪因子在血管重塑中起作用。总之，这些结果表明，FABP4 诱导的 DNA 合成和细胞迁移主要通过激活 HCASMC 中的转录因子 c-jun 和 c-myc 的 MAPK 依赖性途径来介导。
