Lazaroid U-74389G inhibits the osteoblastic differentiation of IL-1β-indcued aortic valve interstitial cells through glucocorticoid receptor and inhibition of NF-κB pathway

Background: Aortic valve calcification is characterized as the active process of aortic valve interstitial cells (AVICs), and considered as an inflammatory disease. As an antioxidant, the anti-inflammatory activity of Lazaroid has been exhibited in various models. We hypothesized that Lazaroid U-74389G would inhibit the osteoblastic differentiation of AVICs induced by IL-1 beta. Methods: Normal tricuspid aortic valve leaflets were collected from patients with acute aortic dissection (Type A) undergoing the Bentall procedure. AVICs were isolated and stimulated with IL-1 beta in presence or absence of U-74389G in culture. Cell lysates were analyzed for osteogenic markers and nuclear factor-kappa B using real-time PCR and Immunoblotting. Culture media was analyzed for IL-6 and IL-8 with enzyme-linked immunosorbent assay. Alizarin Red Staining was adopted to demonstrate the calcium deposition. Results: The expression of alkaline phosphatase and bone morphogenetic protein, accompanied by the production of IL-6 and IL-8, was up-regulated in response to IL-1 beta and was inhibited by the addition of U-74389G. The NF-kappa B pathway was activated by IL-1 beta and involved in the suppression of U-74389G on osteoblastic differentiation in AVICs. The negative effects of U-74389G on ostengenic gene expression and mineralization of AVICs were blocked by glucocorticoid receptor antagonist mifepristone and the NF-kappa B inhibitor Bay 11-7082. Conclusions: U-74389G inhibits the pro-osteogenic response to IL-1 beta stimulation in AVICs. The osteoblastic differentiation and mineralization of AVICs were inhabited by U-74389G though the modulation of NF-kappa B activation, and this pathway could be potential therapeutic targets for medical treatment of calcified aortic valve disease. (C) 2015 Elsevier Ltd. All rights reserved.