From the Research Centre for Molecular Medicine (E.B., A.T., V.J.), Faculty of Medicine, University of Debrecen, Hungary.
Department of Pathology (G.M.), Faculty of Medicine, University of Debrecen, Hungary.
Arterioscler Thromb Vasc Biol. 2019 Jun;39(6):1088-1099. doi: 10.1161/ATVBAHA.119.312509.
Objective- Vascular calcification is associated with high risk of cardiovascular events and mortality. Osteochondrogenic differentiation of vascular smooth muscle cells (VSMCs) is the major cellular mechanism underlying vascular calcification. Because tissue hypoxia is a common denominator in vascular calcification, we investigated whether hypoxia per se triggers osteochondrogenic differentiation of VSMCs. Approach and Results- We studied osteochondrogenic differentiation of human aorta VSMCs cultured under normoxic (21% O) and hypoxic (5% O) conditions. Hypoxia increased protein expression of HIF (hypoxia-inducible factor)-1α and its target genes GLUT1 (glucose transporter 1) and VEGFA (vascular endothelial growth factor A) and induced mRNA and protein expressions of osteochondrogenic markers, that is, RUNX2 (runt-related transcription factor 2), SOX9 (Sry-related HMG box-9), OCN (osteocalcin) and ALP (alkaline phosphatase), and induced a time-dependent calcification of the extracellular matrix of VSMCs. HIF-1 inhibition by chetomin abrogated the effect of hypoxia on osteochondrogenic markers and abolished extracellular matrix calcification. Hypoxia triggered the production of reactive oxygen species, which was inhibited by chetomin. Scavenging reactive oxygen species by N-acetyl cysteine attenuated hypoxia-mediated upregulation of HIF-1α, RUNX2, and OCN protein expressions and inhibited extracellular matrix calcification, which effect was mimicked by a specific hydrogen peroxide scavenger sodium pyruvate and a mitochondrial reactive oxygen species inhibitor rotenone. Ex vivo culture of mice aorta under hypoxic conditions triggered calcification which was inhibited by chetomin and N-acetyl cysteine. In vivo hypoxia exposure (10% O) increased RUNX2 mRNA levels in mice lung and the aorta. Conclusions- Hypoxia contributes to vascular calcification through the induction of osteochondrogenic differentiation of VSMCs in an HIF-1-dependent and mitochondria-derived reactive oxygen species-dependent manner.
血管钙化与心血管事件和死亡率的高风险相关。血管平滑肌细胞（VSMC）的成骨软骨分化是血管钙化的主要细胞机制。由于组织缺氧是血管钙化的共同特征，我们研究了缺氧本身是否会触发 VSMC 的成骨软骨分化。
我们研究了在常氧（21% O）和低氧（5% O）条件下培养的人主动脉 VSMC 的成骨软骨分化。低氧增加了 HIF（缺氧诱导因子）-1α及其靶基因 GLUT1（葡萄糖转运蛋白 1）和 VEGFA（血管内皮生长因子 A）的蛋白表达，并诱导了成骨软骨标志物的 mRNA 和蛋白表达，即 RUNX2（runt-related transcription factor 2）、SOX9（Sry-related HMG box-9）、OCN（骨钙素）和 ALP（碱性磷酸酶），并诱导 VSMC 细胞外基质的时间依赖性钙化。HIF-1 抑制剂 chetomin 阻断了低氧对成骨软骨标志物的作用，并消除了细胞外基质的钙化。低氧触发了活性氧的产生，而 chetomin 抑制了活性氧的产生。N-乙酰半胱氨酸清除活性氧减轻了低氧介导的 HIF-1α、RUNX2 和 OCN 蛋白表达的上调，并抑制了细胞外基质的钙化，这种作用被特异性过氧化氢清除剂丙酮酸钠和线粒体活性氧抑制剂鱼藤酮模拟。在低氧条件下对小鼠主动脉进行的离体培养引发了钙化，而 chetomin 和 N-乙酰半胱氨酸抑制了这种钙化。体内低氧暴露（10% O）增加了小鼠肺和主动脉中 RUNX2 的 mRNA 水平。
缺氧通过 HIF-1 依赖性和线粒体来源的活性氧依赖性方式诱导 VSMC 的成骨软骨分化，从而促进血管钙化。
