IL-6 gene expression is controlled by a promoter region containing multiple regulatory elements such as NF-B, NF-IL6, CRE, GRE, and TRE. In this study, we demonstrated that TRE, found within the IL-6 promoter, is embedded in a functional antioxidant response element (ARE) matching an entire ARE consensus sequence. Further, point mutations of the ARE consensus sequence in the IL-6 promoter construct selectively eliminate ARE but not TRE activity. Nrf2 is a redox-sensitive transcription factor which provides cytoprotection against electrophilic and oxidative stress and is the most potent activator of ARE-dependent transcription. Using Nrf2 knock-out mice we demonstrate that Nrf2 is a potent activator of IL-6 gene transcription in vivo. Moreover, we show evidence that Nrf2 is the transcription factor that activates IL6 expression in a cholestatic hepatitis mouse model. Our findings suggest a possible role of IL-6 in oxidative stress defense and also give indication about an important function for Nrf2 in the regulation of hematopoietic and inflammatory processes.Because of its diverse biological function and simultaneous description in different studies, IL-6 was initially assigned several names. It was identified as a T-cell-derived B-cell differentiation factor, as it induced activated B-cells into antibody-producing cells: interferon-␤2 (26 kDa protein), a hybridoma/plasmacytoma growth factor and a hepatocytestimulating factor. The name IL-6 was proposed when the cDNA nucleotide sequences for these proteins had been determined, and the molecules were found to be identical (1). In addition, IL-6 plays a key role in inflammation, being the main inducer of fibrinogen, serum amyloid A protein, the acute phase response and is one of the most important mediators of fever. In muscle and fatty tissues, IL-6 stimulates energy mobilization.The IL-6 promoter is rapidly activated by cytokines, including IL-1 and TNF-␣, as well as by phorbol esters and cyclic AMP. The promoter-region of the IL-6 gene contains multiple regulatory elements such as nuclear factor-B (NF-B), nuclear factor-IL6 (NF-IL6) (also referred to as C/EBP␤), cAMP response element (CRE), TPA (12-O-tetradecanoylphorbol-13-acetate) responsive element (TRE; also referred to as the AP-1 binding site), and the glucocorticoid response element (GRE) (2).Structurally related to TRE is the antioxidant responsive element (ARE, 2 also referred to as the electrophile responsive element (EpRE)) (3, 4). Some TREs are found to be embedded within an ARE, such as in the promoter region of human NAD(P)H:quinine oxidoreductase-1 (NQO1), rat and mouse glutathione S-transferase (GST) Ya subunit, and rat GST-P (5). ARE is commonly found in the promoter region of genes encoding phase II detoxification as well as antioxidant enzymes such as NQO1, thioredoxin, thioredoxin reductase, glutathione peroxidase, and hemeoxygenase-1 (6). Analyses of ARE-nuclear protein complexes have identified numerous nuclear transcription factors including c-Jun, Jun-B, Jun-D, c-Fos, Fra1, Nrf1, Nrf2, ...

Background— Diabetes mellitus predisposes to thrombotic and proliferative vascular remodeling, to which thrombin contributes via activation of protease-activated receptor (PAR) 1. However, the use of PAR-1 inhibitors to suppress remodeling may be limited by severe bleeding. We recently reported upregulation of an additional thrombin receptor, PAR-4, in human vascular smooth muscle cells exposed to high glucose and have now examined PAR-4 as a novel mediator linking hyperglycemia, hypercoagulation, and vascular remodeling in diabetes mellitus. Methods and Results— PAR-4 expression was increased in carotid atherectomies and saphenous vein specimens from diabetic versus nondiabetic patients and in aorta and carotid arteries from streptozotocin-diabetic versus nondiabetic C57BL/6 mice. Vascular PAR-1 mRNA was not increased in diabetic mice. Ligated carotid arteries from diabetic mice developed more extensive neointimal hyperplasia and showed greater proliferation than arteries from nondiabetic mice. The augmented remodeling response was absent in diabetic mice deficient in PAR-4. At the cellular level, PAR-4 expression was controlled via the mRNA stabilizing actions of human antigen R, which accounted for the stimulatory actions of high glucose, angiotensin II, and H 2 O 2 on PAR-4 expression, whereas cicaprost via protein kinase A activation counteracted this effect. Conclusions— PAR-4 appears to play a hitherto unsuspected role in diabetic vasculopathy. The development of PAR-4 inhibitors might serve to limit mainly proliferative processes in restenosis-prone diabetic patients, particularly those patients in whom severe bleeding attributed to selective PAR-1 blockade or complete thrombin inhibition must be avoided or those who do not require anticoagulation.