Effects of Oxidized Low Density Lipoprotein on Transformation of Valvular Myofibroblasts to Osteoblast-like Phenotype

• Published in: Journal of Huazhong University of Science and Technology. Medical sciences Vol. 35; no. 3; pp. 362 - 367
• Main Author: 陈娣 诜迎念 胡伟林 陈正平 李永胜
• Format: Journal Article
• Language: English
• Published: Wuhan Huazhong University of Science and Technology 01.06.2015; Department of Emergency Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology,Wuhan 430030, China
• Subjects: Actins - metabolism; Animals; Aortic Valve - cytology; beta Catenin - metabolism; Cell Differentiation - drug effects; Cells, Cultured; Gene Expression Regulation - drug effects; Intercellular Signaling Peptides and Proteins - pharmacology; Lipoproteins, LDL - pharmacology; Medicine; Medicine & Public Health; Myofibroblasts - drug effects; Osteoblasts - physiology; Phenotype; Swine; Wnt Signaling Pathway - drug effects; Wnt信号通路; β-catenin; 型转化; 心脏瓣膜; 成骨细胞; 氧化型低密度脂蛋白; 纤维母细胞; 肌成纤维细胞; oxidized low density lipoprotein; cardiac valve calcification; osteoblasts; myofibroblasts; Wnt/β-catenin
• ISSN: 1672-0733; 1993-1352; 1993-1352
• DOI: 10.1007/s11596-015-1438-x

In order to investigate the roles of Wnt signal pathway in transformation of cardiac valvular myofibroblasts to the osteoblast-like phenotype, the primary cultured porcine aortic valve myofibroblasts were incubated with oxidized low density lipoprotein（ox-LDL, 50 mg/L）, and divided into four groups according to the ox-LDL treatment time： control group, ox-LDL 24-h group, ox-LDL 48-h group, and ox-LDL 72-h group. Wnt signal pathway blocker Dickkopf-1（DDK-1, 100 μg/L） was added in ox-LDL 72-h group. The expression of α-smooth muscle actin（α-SMA）, bone morphogenetic protein 2（BMP2）, alkaline phosphatase（ALP）, and osteogenic transcription factor Cbfa-1 was detected by Western blotting, and that of β-catenin, a key mediator of Wnt signal pathway by immunocytochemical staining method. The Wnt/β-catenin was observed and the transformation of myofibroblasts to the osteoblast-like phenotype was examined. The expression of α-SMA, BMP2, ALP and Cbfa-1 proteins in the control group was weaker than in the ox-LDL-treated groups. In ox-LDL-treated groups, the protein expression of α-SMA, BMP2, ALP, and Cbfa-1 was significantly increased in a time-dependent manner as compared with the control group, and there was significant difference among the three ox-LDL-treated groups（P〈0.05 for all）; β-catenin protein was also up-regulated in the ox-LDL-treated groups in a time-dependent manner as compared with the control group（P〈0.05）, and its transfer from cytoplasm to nucleus and accumulation in the nucleus were increased in the same fashion（P〈0.05）. After addition of DKK-1, the expression of α-SMA, bone-related proteins and β-catenin protein was significantly reduced as compared with ox-LDL 72-h group（P〈0.05）. The Wnt/ β-catenin signaling pathway may play an important role in transformation of valvular myofibroblasts to the osteoblast-like phenotype.