Wang Bo, Li Fei, Zhang Chao, Wei Guangxia, Liao Pingping, Dong Nianguo
Department of Cardiovascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China.
Department of Cardiothoracic Surgery, Huangshi Central Hospital, Huangshi, China.
J Thorac Cardiovasc Surg. 2016 Jan;151(1):255-62. doi: 10.1016/j.jtcvs.2015.09.077. Epub 2015 Sep 28.
Calcific aortic valve (AV) disease is known to be an inflammation-related process. High-mobility group box-1 (HMGB1) protein and Toll-like receptor 4 (TLR4) have been reported to participate in several inflammatory diseases. The purpose of the present study was to determine whether the HMGB1-TLR4 axis is involved in calcific AV disease, and to evaluate the effect of HMGB1, and its potential mechanisms, on the pro-osteogenic phenotype change of valvular interstitial cells (VICs).
Expression of HMGB1 and TLR4 in human calcific AVs was evaluated using immunohistochemical staining and immunoblotting. Cultured VICs were used as an in vitro model. The VICs were stimulated with HMGB1 for analysis, with versus without TLR4 small interfering ribonucleic acid (siRNA), c-Jun N-terminal kinase mitogen-activated protein kinase (JNK MAPK), and nuclear factor kappa-B (NF-κB) inhibitors.
Enhanced accumulation of HMGB1 and TLR4 was observed in calcific valves. Moreover, we found that HMGB1 induced high levels of pro-inflammatory cytokine production and promoted the osteoblastic differentiation and calcification of VICs. In addition, HMGB1 induced phosphorylation of JNK MAPK and NF-κB. However, these effects were markedly suppressed by siRNA silencing of TLR4. In addition, blockade of JNK MAPK and NF-κB phosphorylation prohibited HMGB1-induced production of pro-osteogenic factors, and mineralization of VICs.
The HMGB1 protein may promote osteoblastic differentiation and calcification of VICs, through the TLR4-JNK-NF-κB signaling pathway.
已知钙化性主动脉瓣疾病是一个与炎症相关的过程。据报道，高迁移率族蛋白B1（HMGB1）和Toll样受体4（TLR4）参与了多种炎症性疾病。本研究的目的是确定HMGB1 - TLR4轴是否参与钙化性主动脉瓣疾病，并评估HMGB1对瓣膜间质细胞（VICs）促骨生成表型变化的影响及其潜在机制。
采用免疫组织化学染色和免疫印迹法评估人钙化性主动脉瓣中HMGB1和TLR4的表达。培养的VICs用作体外模型。用HMGB1刺激VICs进行分析，同时使用或不使用TLR4小干扰核糖核酸（siRNA）、c - Jun氨基末端激酶丝裂原活化蛋白激酶（JNK MAPK）和核因子κB（NF - κB）抑制剂。
在钙化瓣膜中观察到HMGB1和TLR4的积累增强。此外，我们发现HMGB1诱导高水平的促炎细胞因子产生，并促进VICs的成骨细胞分化和钙化。此外，HMGB1诱导JNK MAPK和NF - κB磷酸化。然而，TLR4的siRNA沉默显著抑制了这些作用。此外，JNK MAPK和NF - κB磷酸化的阻断阻止了HMGB1诱导的促骨生成因子的产生以及VICs的矿化。
HMGB1蛋白可能通过TLR4 - JNK - NF - κB信号通路促进VICs的成骨细胞分化和钙化。
