Abstract:Monocytes and macrophages participate in a wide variety of host defense mechanisms. Annexin II, a fibrinolytic receptor, binds plasminogen and tissue plasminogen activator (t-PA) independently at the cell surface, thereby enhancing the catalytic efficiency of plasmin production. We demonstrated previously that annexin II on the surface of both cultured monocytoid cells and monocyte-derived macrophages promotes their ability to remodel extracellular matrix. Here, we demonstrate that human peripheral blood monoc… Show more
“…By functioning as a receptor for  2 GPI, annexin II is a target not only for anti-annexin II antibodies but also for anti- 2 GPI antibodies, which are direct inducers of TF overexpression and thus are significantly associated with thrombosis in the setting of APS (18). Recently, it has also been demonstrated that annexin II plays an important role in human monocyte/macrophage-directed migration and recruitment and that it is activated on progression from monocytes to macrophages (24). Thus, annexin II might constitute a common receptor for aPL induction of monocyte activation.…”
Objective. Antiphospholipid antibodies (aPL) are closely related to the development of thrombosis, but the exact mechanism(s) leading to thrombotic events remains unknown. In this study, using proteomic techniques, we evaluated changes in protein expression of monocytes from patients with antiphospholipid syndrome (APS) related to the pathophysiology of the syndrome.Methods. Fifty-one APS patients were included. They were divided into 2 groups: patients with previous thrombosis, and patients with recurrent spontaneous abortion. As controls, we studied patients with thrombosis but without aPL, and age-and sex-matched healthy subjects.Results. The proteins that were more significantly altered among monocytes from APS patients with thrombosis (annexin I, annexin II, protein disulfide isomerase, Nedd8, RhoA proteins, and Hsp60) were functionally related to the induction of a procoagulant state as well as to autoimmune-related responses. Proteins reported to be connected to recurrent spontaneous abortion (e.g., fibrinogen and hemoglobin) were also determined to be significantly deregulated in APS patients without thrombosis. In vitro treatment with IgG fractions purified from the plasma of APS patients with thrombosis changed the pattern of protein expression of normal monocytes in the same way that was observed in vivo for monocytes from APS patients with thrombosis.
“…By functioning as a receptor for  2 GPI, annexin II is a target not only for anti-annexin II antibodies but also for anti- 2 GPI antibodies, which are direct inducers of TF overexpression and thus are significantly associated with thrombosis in the setting of APS (18). Recently, it has also been demonstrated that annexin II plays an important role in human monocyte/macrophage-directed migration and recruitment and that it is activated on progression from monocytes to macrophages (24). Thus, annexin II might constitute a common receptor for aPL induction of monocyte activation.…”
Objective. Antiphospholipid antibodies (aPL) are closely related to the development of thrombosis, but the exact mechanism(s) leading to thrombotic events remains unknown. In this study, using proteomic techniques, we evaluated changes in protein expression of monocytes from patients with antiphospholipid syndrome (APS) related to the pathophysiology of the syndrome.Methods. Fifty-one APS patients were included. They were divided into 2 groups: patients with previous thrombosis, and patients with recurrent spontaneous abortion. As controls, we studied patients with thrombosis but without aPL, and age-and sex-matched healthy subjects.Results. The proteins that were more significantly altered among monocytes from APS patients with thrombosis (annexin I, annexin II, protein disulfide isomerase, Nedd8, RhoA proteins, and Hsp60) were functionally related to the induction of a procoagulant state as well as to autoimmune-related responses. Proteins reported to be connected to recurrent spontaneous abortion (e.g., fibrinogen and hemoglobin) were also determined to be significantly deregulated in APS patients without thrombosis. In vitro treatment with IgG fractions purified from the plasma of APS patients with thrombosis changed the pattern of protein expression of normal monocytes in the same way that was observed in vivo for monocytes from APS patients with thrombosis.
“…Recently, the annexin A2 heterotetramer has been identified as a receptor for plasmin-induced signaling in human monocytes (25). Moreover, annexin A2 has been linked to plasminogen-dependent matrix invasion by monocytes (46,47). Annexin A2, a member of a family of proteins that bind anionic phospholipids in a Ca 2ϩ -dependent manner, exists in three forms, a monomer (p36), a heterodimer, or a heterotetramer.…”
Chronic inflammatory diseases are associated with connective tissue turnover that involves a series of proteases, which include the plasminogen activation system and the family of matrix metalloproteinases (MMPs). Urokinase-type plasminogen activator (uPA) and plasmin, in addition to their role in fibrinolysis and activation of pro-MMPs, have been shown to transduce intracellular signals through specific receptors. The potential for uPA and plasmin to also contribute to connective tissue turnover by directly regulating MMP production was examined in human monocytes. Both catalytically active high m.w. uPA, which binds to the uPAR, and low m.w. uPA, which does not, significantly enhanced MMP-1 synthesis by activated human monocytes. In contrast, the N-terminal fragment of uPA, which binds to uPAR, but lacks the catalytic site, failed to induce MMP-1 production, indicating that uPA-stimulated MMP-1 synthesis was plasmin dependent. Endogenous plasmin generated by the action of uPA or exogenous plasmin increased MMP-1 synthesis by signaling through annexin A2, as demonstrated by inhibition of MMP-1 production with Abs against annexin A2 and S100A10, a dimeric protein associated with annexin A2. Interaction of plasmin with annexin A2 resulted in the stimulation of ERK1/2 and p38 MAPK, cyclooxygenase-2, and PGE2, leading to increased MMP-1 production. Furthermore, binding of inactive plasmin to annexin A2 inhibited plasmin induction of MMP-1, suggesting that inactive plasmin may be useful in suppressing inflammation.
“…Previous studies have implicated ANXA2 in various biological functions, including mitogenic signal transduction, fibrinolysis, immune response, proliferation, carcinogenesis and tumor progression (7)(8)(9)(10)(11). ANXA2 has been demonstrated to be a co-receptor for both plasminogen and tissue-type plasminogen activator, which cleaves inactive plasminogen to yield the active serine proteinase, plasmin (12,13). Subsequent studies elucidated that the conversion of plasminogen to plasmin is induced by ANXA2 promoting metastasis, which leads to the activation of metalloproteinases, degradation of extracellular matrix components, and promotion of neoangiogenesis (14)(15)(16)(17).…”
Abstract. The epidermal growth factor receptor (EGF-R) signaling pathway is thought to have an important role in the development and progression of several carcinomas, as it is associated with cell proliferation, differentiation and migration. Activation of EGF-R signaling regulates epithelial-mesenchymal transition (EMT)-associated invasion and migration in normal and malignant epithelial cells. However, the specific mechanisms have not yet been fully elucidated. The present study utilized wound healing assays, western blotting, flow cytometry and MTT assays to demonstrate that Annexin A2 (ANXA2) is a key regulatory factor in EGF-induced EMT in CaSki cervical cancer cells. Moreover, the increased expression levels of ANXA2 promoted cell viability and migration in human CaSki cells. It was also found that silencing ANXA2 partially reverses EGF-induced EMT and inhibits cell viability and migration in CaSki cells. These findings suggest that ANXA2 is a key regulator of EGF-induced EMT in CaSki cervical cancer cells.
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