Department of Pharmacology, School of Medicine, Pusan National University, Yangsan, Gyeongnam 626-870, Republic of Korea.
Toxicol Appl Pharmacol. 2012 Apr 1;260(1):89-94. doi: 10.1016/j.taap.2012.01.026. Epub 2012 Feb 3.
Homocysteine (Hcy) at elevated levels is an independent risk factor of cardiovascular diseases, including atherosclerosis. In the present study, we investigated the effect of Hcy on the production of matrix metalloproteinases (MMP) in murine macrophages. Among the MMP known to regulate the activities of collagenase and gelatinase, Hcy exclusively increased the gelatinolytic activity of MMP-9 in J774A.1 cells as well as in mouse peritoneal macrophages. Furthermore, this activity was found to be correlated with Western blot findings in J774A.1 cells, which showed that MMP-9 expression was concentration- and time-dependently increased by Hcy. Inhibition of the ERK and Akt pathways led to a significant decrease in Hcy-induced MMP-9 expression, and combined treatment with inhibitors of the ERK and Akt pathways showed an additive effects. Activity assays for ERK and Akt showed that Hcy increased the phosphorylation of both, but these phosphorylation were not affected by inhibitors of the Akt and ERK pathways. In line with these findings, the molecular inhibition of ERK and Akt using siRNA did not affect the Hcy-induced phosphorylation of Akt and ERK, respectively. Taken together, these findings suggest that Hcy enhances MMP-9 production in murine macrophages by separately activating the ERK and Akt signaling pathways.
同型半胱氨酸（Hcy）水平升高是心血管疾病（包括动脉粥样硬化）的一个独立危险因素。在本研究中，我们研究了 Hcy 对小鼠巨噬细胞基质金属蛋白酶（MMP）产生的影响。在已知调节胶原酶和明胶酶活性的 MMP 中，Hcy 仅增加了 J774A.1 细胞以及小鼠腹腔巨噬细胞中 MMP-9 的明胶酶活性。此外，这项活性与 J774A.1 细胞中的 Western blot 结果相关，Western blot 结果显示 MMP-9 的表达被 Hcy 浓度和时间依赖性地增加。ERK 和 Akt 通路的抑制导致 Hcy 诱导的 MMP-9 表达显著减少，而 ERK 和 Akt 通路抑制剂的联合治疗显示出相加效应。ERK 和 Akt 的活性测定表明，Hcy 增加了两者的磷酸化，但这些磷酸化不受 Akt 和 ERK 通路抑制剂的影响。与这些发现一致的是，使用 siRNA 对 ERK 和 Akt 的分子抑制分别不影响 Hcy 诱导的 Akt 和 ERK 的磷酸化。综上所述，这些发现表明 Hcy 通过分别激活 ERK 和 Akt 信号通路增强了小鼠巨噬细胞中 MMP-9 的产生。
