Jingxin Zhou1, Jinfu Zhu1, Li Jiang2, Busheng Zhang3, Dan Zhu4, Yanhu Wu5. 1. Department of Cardiovascular Surgery, the First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China. 2. Department of Cardiology, the First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China. 3. Department of Cardiovascular Surgery, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China. 4. Department of Cardiovascular Surgery, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai, China. Electronic address: zhudanmd@163.com. 5. Department of Cardiovascular Surgery, the First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China. Electronic address: wuyh@sohu.com.
Abstract
BACKGROUND: Calcific aortic valve disease is the main heart valve disease in the elderly. Valvular interstitial cells (VICs) play an important role in the process of valve calcification. Interleukin 18 (IL-18) is expressed in stenosis aortic valves and is positively related with the clinical severity of aortic stenosis. However, the role of IL-18 in aortic valve calcification remains unclear. This study examined whether IL-18 promotes myofibroblast and/or osteoblast transdifferention of VICs. Porcine VICs were isolated and treated with recombinant porcine IL-18. METHODS: Porcine VICs were cultured and treated with IL-18. Gene and protein expression of myofibroblastic and osteoblastic markers were tested and nuclear factor κB (NF-κB) phosphorylation was also analyzed. Alkaline phosphatase (ALP) staining and activity assay were also performed. RESULTS: Our experiments demonstrated that IL-18 significantly enhanced alpha-smooth muscle actin (α-SMA) gene and protein expression. IL-18 treatment also promoted the expression of osteopontin (OPN) and runt-related transcription factor 2 (Runx2) mRNA, although OPN and Runx2 protein expressions were not changed. IL-18 could induce ALP activity in the presence of conditioning medium. We also demonstrated that IL-18 markedly enhanced NF-κB p65 phosphorylation in VICs. CONCLUSIONS: Together these results suggest that IL-18 promotes the myofibroblast differentiation of VICs and accelerates calcification in the presence of conditioning medium via the NF-κB pathway.
BACKGROUND:Calcific aortic valve disease is the main heart valve disease in the elderly. Valvular interstitial cells (VICs) play an important role in the process of valve calcification. Interleukin 18 (IL-18) is expressed in stenosis aortic valves and is positively related with the clinical severity of aortic stenosis. However, the role of IL-18 in aortic valve calcification remains unclear. This study examined whether IL-18 promotes myofibroblast and/or osteoblast transdifferention of VICs. Porcine VICs were isolated and treated with recombinant porcine IL-18. METHODS: Porcine VICs were cultured and treated with IL-18. Gene and protein expression of myofibroblastic and osteoblastic markers were tested and nuclear factor κB (NF-κB) phosphorylation was also analyzed. Alkaline phosphatase (ALP) staining and activity assay were also performed. RESULTS: Our experiments demonstrated that IL-18 significantly enhanced alpha-smooth muscle actin (α-SMA) gene and protein expression. IL-18 treatment also promoted the expression of osteopontin (OPN) and runt-related transcription factor 2 (Runx2) mRNA, although OPN and Runx2 protein expressions were not changed. IL-18 could induce ALP activity in the presence of conditioning medium. We also demonstrated that IL-18 markedly enhanced NF-κB p65 phosphorylation in VICs. CONCLUSIONS: Together these results suggest that IL-18 promotes the myofibroblast differentiation of VICs and accelerates calcification in the presence of conditioning medium via the NF-κB pathway.