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Macrophages as inflammatory cells are involved in the pathogenesis of atherosclerosis that today is recognized as an inflammatory disease. Activation of coagulation leads to the late complication of atherosclerosis, namely atherothrombosis with its clinical manifestations stroke, unstable angina, myocardial infarction, and sudden cardiac death. Thus inflammation and coagulation play fundamental roles in the pathogenesis of atherosclerosis. We show that the coagulation enzyme thrombin up-regulates oncostatin M (OSM), a pleiotropic cytokine implicated in the pathophysiology of vascular disease, in human monocyte-derived macrophages (MDMs) up to 16.8-fold. A similar effect was seen in human peripheral blood monocytes and human plaque macrophages. In MDMs, the effect of thrombin on OSM was abolished by PPACK and mimicked by a PAR-1-specific peptide. Thrombin induced phosphorylation of ERK1/2 and p38 in MDMs. The ERK1/2 inhibitor PD98059 blocked the effect of thrombin on OSM production in MDMs, whereas the p38 inhibitor SB202190 had no effect. Thrombin induced translocation of c-fos and c-jun to the nucleus of MDMs. Using OSM promoter-luciferase reporter constructs transfected into MDMs, we show that a functional AP-1 site is required for promoter activation by thrombin. We present another link between coagulation and inflammation, which could impact on the pathogenesis of atherosclerosis. IntroductionMacrophages as inflammatory cells, which produce an array of inflammatory mediators, growth factors, and proteases are critically involved in the pathogenesis of atherosclerosis that today is recognized as an inflammatory disease. 1,2 Rupture of advanced atherosclerotic lesions leads to activation of the coagulation cascade, resulting in thrombin generation and subsequently in atherothrombosis with its clinical complications such as stroke, unstable angina, myocardial infarction, and sudden cardiac death, which are the most common causes of morbidity and mortality in the Western world today. [3][4][5][6][7][8] The central coagulation enzyme thrombin acts as a proinflammatory mediator and is chemotactic for monocytes and stimulates their proliferation and phagocytic activity. [9][10][11][12][13] In monocytes and macrophages, thrombin induces the production of inflammatory cytokines with well-established roles in cardiovascular disease such as interleukin-1 (IL-1), monocyte chemoattractant protein-1, and IL-6, a member of the IL-6 family of cytokines. [14][15][16][17][18] In this paper we have addressed the question whether thrombin affects the expression of yet another member of the IL-6 family of cytokines, which is produced mainly by macrophages, namely oncostatin-M (OSM) in these cells. This pleiotropic cytokine, which plays a critical role in numerous physiologic and pathophysiologic processes including inflammation, hematopoiesis, tissue remodeling, development, and cell growth, has been implicated recently in the pathophysiology of cardiovascular disease. [19][20][21][22][23][24] In vascular smooth muscle cells, O...

Objective-Macrophages produce the cytokine oncostatin M (OSM), which beside other functions is also involved in inflammation. The complement component C5a mobilizes and activates these cells at inflammatory sites. We examined the effect of C5a on OSM production in human monocytes and in human monocyte-derived macrophages. Methods and Results-For macrophage transformation peripheral blood monocytes were cultivated for 8 to 10 days in the presence of human serum. C5a significantly increased in these cells OSM antigen as determined by specific ELISA and mRNA as quantitated by real-time polymerase chain reaction in these cells as well as in plaque macrophages. This effect was blocked by antibodies against the receptor C5aR/CD88 and by pertussis toxin. The C5a-induced phosphorylation of p38 and JNK and the C5a-induced increase in OSM production in macrophages was abolished by 2 p38 inhibitors and by a JNK inhibitor. Furthermore C5a increased the nuclear translocation of c-fos and c-jun. Using different OSM promoter deletion mutant constructs we show that the putative AP-1 element is responsible for activation of OSM promoter activity by C5a. Key Words: atherosclerosis Ⅲ macrophages Ⅲ inflammation Ⅲ complement Ⅲ oncostatin M M acrophages by producing a vast array of biomolecules play a key role in a variety of physiological and pathophysiological processes such as immunity, inflammation, and tissue remodeling. 1 Among these biomolecules are various inflammatory cytokines such as tumor necrosis factor (TNF)-␣, interleukin (IL)-1, or IL-6. 2 Macrophages are also considered to be the major producers of oncostatin M (OSM), which is a multifunctional cytokine belonging to the glycoprotein 130 (gp130) receptor cytokine family. 3-5 OSM was originally isolated from phorbol 12-myristate 13-acetate (PMA)-treated human histolytic lymphoma U937 cells and plays a critical role in numerous physiological and pathophysiological events including inflammation, hematopoiesis, tissue remodeling, development, and cell growth. 6,7 Besides macrophages also T cells, neutrophils, osteoblasts, dendritic cells, Kaposi's sarcoma cells, and microglia produce OSM. 8 -13 Its expression is upregulated by granulocyte-macrophage colony stimulating factor (GM-CSF), IL-3, human chorionic gonadotropin (hCG), HIV-1, lipopolysaccharide (LPS), cisplatin, or prostaglandin (PG) E2. 11,[13][14][15][16] The potent anaphylatoxin C5a is generated during complement activation through cleavage of C5 and is released at the inflammatory site. There, C5a mediates immune and inflammatory processes such as increased vascular permeability, spasmogenesis, immune regulation, and the release of a variety of inflammatory cytokines and mediators. 17,18 C5a is a strong chemoattractant and is involved in the recruitment of inflammatory cells such as T lymphocytes, eosinophils, neutrophils, and monocytes and is regarded as the most potent chemoattractant for the latter 2 cell types. 19,20 It contributes to rapid mobilization of phagocytic cells to and activation of these cells...

Rho GTPases regulate diverse cellular functions including adhesion, cytokinesis and motility, as well as the activity of the transcription factors NF-jB, serum response factor and C/EBP. a-Catulin, an a-catenin-related protein that shares structural similarities with cytoskeletal linker proteins, facilitates Rho signalling by serving as a scaffold for the Rho-specific guanine nucleotide exchange factor Lbc. We report here that a-catulin also interacts with a key component of the NF-jB signalling pathway, namely the IjB kinase (IKK)-b. In co-immunoprecipitations, a-catulin can bind IKK-b and Lbc. Ectopic expression of a-catulin augmented NF-jB activity, promoted cell migration and increased resistance to apoptosis, whereas knockdown experiments showed the opposite effects. Together, these features suggest that a-catulin has tumorigenic potential.

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