In a rabbit atherosclerosis model, atorvastatin diminishes the neointimal inflammation, and this could contribute to the stabilization of the atherosclerotic plaque. This may be an additional explanation for the reduction of acute ischemic events in patients treated with statins.

Objective-Suppressors of cytokine signaling (SOCS) proteins are intracellular regulators of receptor signal transduction, mainly Janus kinase/signal transducers and activators of transcription (JAK/STAT). We investigated the effects of SOCS modulation on the JAK/STAT-dependent responses in vascular cells, and their implication in atherosclerotic plaque development. Methods and Results-Immunohistochemistry in human plaques revealed a high expression of SOCS1 and SOCS3 by vascular smooth muscle cells (VSMCs) and macrophages in the inflammatory region of the shoulders, when compared to the fibrous area. SOCS were also increased in aortic lesions from apoE Ϫ/Ϫ mice. In cultured VSMCs, endothelial cells, and monocytes, SOCS1 and SOCS3 were transiently induced by proinflammatory cytokines, proatherogenic lipoproteins, and immune molecules. Furthermore, overexpression of SOCS suppressed STAT activation and reduced inflammatory gene expression and cell growth, whereas SOCS knockdown increased these cell responses. In vivo, antisense oligodeoxynucleotides targeting SOCS3 exacerbated the atherosclerotic process in apoE Ϫ/Ϫ mice by increasing the size, leukocyte content, and chemokine expression in the lesions. Key Words: atherosclerosis Ⅲ inflammation Ⅲ signal transduction Ⅲ proliferation Ⅲ chemokines A therosclerosis is a chronic inflammatory disease that involves a complex interaction of the artery wall and its cellular components, lipoproteins, and circulating blood elements. 1 Leukocyte invasion and vascular smooth muscle cell (VSMC) proliferation are key early events in lesion development. 2 Low-density lipoproteins (LDL) and cytokines, such as interferon ␥ (IFN␥) and interleukin-6 (IL-6), influence the dynamics of vascular cell function and are main mediators of inflammation during atherogenesis. 2,3 Native and modified forms of LDL induce a variety of biological properties, including cytokine expression, changes in monocyte/macrophages motility and arterial vasomotricity, and VSMC mitogenesis. 4,5 IFN␥ is expressed in human and experimental plaques, and induces the expression of major histocompatibility complex-II, downregulates scavenger receptors, and modulates vascular cell proliferation. 2,6 IL-6 is secreted from endothelial cells (ECs), VSMCs, and leukocytes, and has multiple biological activities, including lymphocyte activation, acute-phase proteins induction, and proliferation. 7,8 Evidence supports the involvement of cellular and humoral immune responses in atherosclerosis, from its initiation to its thrombotic complication. 9 Elevated levels of LDL-containing immune complexes (ICs) and their IgG Fc receptors (Fc␥R) have been found in atherosclerotic patients. 10 Furthermore, Fc␥R mediates the clearance of ICs containing LDL and foam cell formation, 10 and Fc␥R activation in vascular cells is critical for atherosclerosis development in mice. 11 The Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway is an essential intracellular mechanism of cytokines and other stimuli tha...

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Background and Purpose-Interaction between different members of the tumor necrosis factor superfamily and their receptors elicits diverse biologic actions that are implicated in the pathogenesis of atherosclerosis. We have analyzed the expression of Fn14 and its ligand TWEAK in carotid atherosclerotic plaques and its potential modulation by atorvastatin in vivo. Furthermore, we have studied whether proinflammatory cytokines regulate Fn14 expression in human aortic smooth muscle cells (hASMCs) in culture as well as the potential regulation by atorvastatin treatment. Methods-Fn14 and TWEAK expression was analyzed in human carotid atherosclerotic plaques. Furthermore, Fn14 expression was studied in hASMCs in culture. Results-Fn14 and TWEAK are expressed in macrophages and smooth muscle cells in carotid atherosclerotic plaques.Proinflammatory cytokines (interleukin-1␤ and interferon-␥) upregulate Fn14 expression in hASMCs. This effect was prevented by atorvastatin treatment and reversed by mevalonate and geranylgeranyl pyrophosphate. Geranylgeranyl transferase inhibitor, toxin B (Rac and Rho inhibitor), C3 exoenzyme (Rho inhibitor), and Y-27632 (Rho kinase inhibitor) also decreased Fn14 expression, implicating the Rho/Rho kinase pathway in the regulation of Fn14 expression. Finally, atorvastatin treatment reduced Fn14 expression in vivo. Conclusions-TWEAK and Fn14 are expressed in atherosclerotic plaques and could be novel mediators of atherosclerosis.Atorvastatin diminishes Fn14 expression in vitro and in vivo providing novel information of the beneficial properties of statins.