WNT/β-catenin signaling promotes VSMCs to osteogenic transdifferentiation and calcification through directly modulating Runx2 gene expression
WNT/β-catenin signaling promotes VSMCs to osteogenic transdifferentiation and calcification through directly modulating Runx2 gene expression
复制标题
WNT/β-连环蛋白信号通过直接调节 Runx2 基因表达促进 VSMC 成骨转分化和钙化
DOI：
10.1016/j.yexcr.2016.06.007
复制
发表时间：
2016-07-15
影响因子：
3.7
通讯作者：
He, Weichun
中科院分区：
文献类型：
--
作者：
Cai, Ting;Sun, Danqin;He, Weichun
动脉内侧钙化（AMC）在慢性肾脏疾病（CKD）患者中很普遍，并导致心血管事件和死亡率升高。高磷酸盐环境下血管平滑肌细胞（VSMCs）向成骨转分化（VOT）参与了CKD中AMC的发病机制。WNT/ β -catenin信号通过促进Runx2在骨祖细胞中的表达而在成骨过程中发挥重要作用，但其在Runx2调控和VOT中的作用尚不完全清楚。在本研究中，高磷酸盐诱导VSMCs的Runx2和激活β -catenin。两种形式的活性β -连环蛋白，Ser37/Thr41位点的去磷酸化和Ser675位点的磷酸化，在高磷酸盐的作用下上调。通过异位表达稳定的β -catenin、抑制GSK-3 β或WNT- 3a蛋白激活β -catenin可诱导Runx2表达，而用Porcupine （PORCN）抑制剂或Dickkopf-1 （DKK1）蛋白阻断WNT/ β -catenin信号通路可抑制高磷酸盐诱导的Runx2。WNT-3A促进VSMCs中骨钙素的表达和钙沉积，而DKK1改善高磷酸盐诱导的VSMCs的钙化。在VSMCs Runx2基因启动子区发现了两个功能性T细胞因子(TCF)/淋巴细胞增强因子结合因子的结合位点，它们在β -连环蛋白激活时与TCF相互作用。它们中的每一个位点定向突变都减弱了Runx2对β -连环蛋白的反应，而它们的缺失或破坏则完全消除了这种反应。在慢性肾功能衰竭大鼠的主动脉膜中，随后是AMC，诱导Runx2和β -catenin， Runx2 mRNA水平与磷酸化β -catenin （Ser675）的丰度呈正相关。综上所述，我们的研究表明，高磷酸盐可能通过不同途径激活WNT/ β -catenin信号，激活的WNT/ β -catenin信号通过直接下游靶点Runx2在促进VOT和AMC中发挥重要作用。(C) 2016年作者。Elsevier Inc.出版。
Arterial medial calcification (AMC) is prevalent in patients with chronic kidney disease (CKD) and contributes to elevated risk of cardiovascular events and mortality. Vascular smooth muscle cells (VSMCs) to osteogenic transdifferentiation (VOT) in a high-phosphate environment is involved in the pathogenesis of AMC in CKD. WNT/beta-catenin signaling is indicated to play a crucial role in osteogenesis via promoting Runx2 expression in osteoprogenitor cells, however, its role in Runx2 regulation and VOT remains incompletely clarified. In this study, Runx2 was induced and beta-catenin was activated by high-phosphate in VSMCs. Two forms of active beta-catenin, dephosphorylated on Ser37/Thr41 and phosphorylated on Ser675 sites, were upregulated by high-phosphate. Activation of beta-catenin, through ectopic expression of stabilized beta-catenin, inhibition of GSK-3 beta, or WNT-3A protein, induced Runx2 expression, whereas blockade of WNT/beta-catenin signaling with Porcupine (PORCN) inhibitor or Dickkopf-1 (DKK1) protein inhibited Runx2 induction by high-phosphate. WNT-3A promoted osteocalcin expression and calcium deposition in VSMCs, whereas DKK1 ameliorated calcification of VSMCs induced by high-phosphate. Two functional T cell factor (TCF)/lymphoid enhancer-binding factor binding sites were identified in the promoter region of Runx2 gene in VSMCs, which interacted with TCF upon beta-catenin activation. Site-directed mutation of each of them attenuated Runx2 response to beta-catenin, and deletion or destruction of both of them completely abolished this responsiveness. In the aortic tunica media of rats with chronic renal failure, followed by AMC, Runx2 and beta-catenin was induced, and the Runx2 mRNA level was positively associated with the abundance of phosphorylated beta-catenin (Ser675). Collectively, our study suggested that high-phosphate may activate WNT/beta-catenin signaling through different pathways, and the activated WNT/beta-catenin signaling, through direct downstream target Runx2, could play an important role in promoting VOT and AMC. (C) 2016 The Authors. Published by Elsevier Inc.