Cui Liwen, Xu Jinsheng, Zhang Junxia, Zhang Muqing, Zhang Shenglei, Bai Yaling
Department of Nephrology, The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei 050011, P.R. China.
Exp Ther Med. 2018 Oct;16(4):3172-3178. doi: 10.3892/etm.2018.6535. Epub 2018 Jul 27.
Vascular calcification (VC) caused by chronic kidney disease (CKD)-mineral and bone disorder is a common complication of CKD. Recent studies have demonstrated that menaquinone-4 (MK-4) is negativly associated with VC in patients with CKD. Furthermore, we have previously shown that runt-related transcription factor 2 (Runx2) is important in the phenotypic transformation process of rat vascular smooth muscle cells (VSMCs), which is the key step for the development of VC. The present study investigated the influence of MK-4 on the phenotypic transformation process of rat VSMCs in order to illustrate its role in the process of VC. Calcification assays were perfomed to access the calcified degree of rat VSMCs. Additionally, the genes and proteins related to phenotypic transformation were measured by reverse transcription-polymerase chain reaction and western blotting methods. It was revealed that calcium deposition in the cells was evidently increased with an addition of β-glycerophosphate (β-GP) and could be completely prevented by co-incubation with MK-4 in a dose-dependent manner. Furthermore, the expression of Runx2 in the β-GP-induced VSMCs was inhibited by MK-4. It was also revealed that the expression of SMAD1 and bone morphogenetic protein (BMP)-2 were decreased in the β-GP-induced VSMCs treated with MK-4 in a dose-dependent manner; however, the expression of SMAD7 was increased in the β-GP-induced VSMCs treated with MK-4 in a dose-dependent manner. These observations suggest that MK-4 reduces mineralization by regulating the BMP-2 signaling pathway in order to attenuate the expression of Runx2.
由慢性肾脏病-矿物质和骨异常（CKD-MBD）引起的血管钙化（VC）是CKD的常见并发症。最近的研究表明，维生素K2（MK-4）与CKD患者的VC呈负相关。此外，我们之前已经表明， runt相关转录因子2（Runx2）在大鼠血管平滑肌细胞（VSMCs）的表型转化过程中起重要作用，这是VC发生的关键步骤。本研究调查了MK-4对大鼠VSMCs表型转化过程的影响，以阐明其在VC过程中的作用。进行钙化测定以评估大鼠VSMCs的钙化程度。此外，通过逆转录-聚合酶链反应和蛋白质印迹法测量与表型转化相关的基因和蛋白质。结果显示，添加β-甘油磷酸（β-GP）后细胞内钙沉积明显增加，而与MK-4共同孵育可呈剂量依赖性完全阻止这种增加。此外，MK-4抑制了β-GP诱导的VSMCs中Runx2的表达。还发现，在MK-4处理的β-GP诱导的VSMCs中，SMAD1和骨形态发生蛋白（BMP）-2的表达呈剂量依赖性降低；然而，在MK-4处理的β-GP诱导的VSMCs中，SMAD7的表达呈剂量依赖性增加。这些观察结果表明，MK-4通过调节BMP-2信号通路来减少矿化，从而减弱Runx2的表达。
