Tumor necrosis factor-α promotes in vitro calcification of vascular cells via the cAMP pathway

• Published in: Circulation (New York, N.Y.) N.Y.), 2000-11, Vol.102 (21), p.2636-2642
• Main Authors: TINTUT, Yin, PATEL, Jignesh, PARHAMI, Farhad, DEMER, Linda L
• Format: Article
• Language: English
• Subjects: Alkaline Phosphatase - genetics; Alkaline Phosphatase - metabolism; Animals; Antigens, Differentiation - metabolism; Biological and medical sciences; Blood vessels and receptors; Bone Matrix - drug effects; Bone Matrix - metabolism; Bone Matrix - pathology; Calcinosis - chemically induced; Calcinosis - pathology; Cattle; Cell Adhesion Molecules - metabolism; Cell Differentiation - drug effects; Cells, Cultured; Core Binding Factor Alpha 1 Subunit; Cyclic AMP - metabolism; Cyclic AMP Response Element-Binding Protein - metabolism; Fundamental and applied biological sciences. Psychology; Intracellular Fluid - metabolism; Muscle, Smooth, Vascular - drug effects; Muscle, Smooth, Vascular - metabolism; Muscle, Smooth, Vascular - pathology; Neoplasm Proteins; Osteoblasts - drug effects; Osteoblasts - enzymology; Osteoblasts - pathology; RNA, Messenger - metabolism; Second Messenger Systems - drug effects; Signal Transduction - drug effects; Transcription Factor AP-1 - metabolism; Transcription Factors - metabolism; Tumor Necrosis Factor-alpha - metabolism; Tumor Necrosis Factor-alpha - pharmacology; Vertebrates: cardiovascular system
• ISSN: 0009-7322; 1524-4539
• DOI: 10.1161/01.CIR.102.21.2636

Vascular calcification is an ectopic calcification that commonly occurs in atherosclerosis. Because tumor necrosis factor-alpha (TNF-alpha), a pleiotropic cytokine found in atherosclerotic lesions, is also a regulator of bone formation, we investigated the role of TNF-alpha in in vitro vascular calcification. A cloned subpopulation of bovine aortic smooth muscle cells previously shown capable of osteoblastic differentiation was treated with TNF-alpha, and osteoblastic differentiation and mineralization were assessed. Treatment of vascular cells with TNF-alpha for 3 days induced an osteoblast-like morphology. It also enhanced both activity and mRNA expression of alkaline phosphatase, an early marker of osteoblastic differentiation. Continuous treatment with TNF-alpha for 10 days enhanced matrix mineralization as measured by radiolabeled calcium incorporation in the matrix. Pretreatment of cells with a protein kinase A-specific inhibitor, KT5720, attenuated cell morphology, the alkaline phosphatase activity, and mineralization induced by TNF-alpha. Consistent with this, the intracellular cAMP level was elevated after TNF-alpha treatment. Electrophoretic mobility shift assay demonstrated that TNF-alpha enhanced DNA binding of osteoblast specific factor (Osf2), AP1, and CREB, transcription factors that are important for osteoblastic differentiation. These results suggest that TNF-alpha enhances in vitro vascular calcification by promoting osteoblastic differentiation of vascular cells through the cAMP pathway.