Characterization of alpha-enolase as an interferon-alpha 2 alpha 1 regulated gene

Abstract

Interferons (IFNs) are multifunctional cytokines that after binding to the cell surface receptor induce the expression of a large number of genes, which in turn, mediate many biological processes including host defense, cell growth control, signaling, and metabolism. Here we show that IFN-alpha activates the mitogen-activated protein kinases (MAPK) ERK1/2 and the transcription factor CREB/ATF-1, which lead to the alpha-enolase (alpha-ENO) gene expression in fibroblasts. Alpha-ENO mRNA accumulation was apparent 6 h post-IFN stimulation and required both de novo protein synthesis and active gene transcription, which is typical of a secondary response gene. Alpha-ENO expression does not appear to be restricted to fibroblasts, since it was equally verified in peripheral blood mononuclear cells (PBMC). Furthermore, IFN-alpha stimulates the expression of the primary response genes c-fos and egr-1, which was followed by an increase in DNA binding activity of c-FOS and EGR-1 proteins, as verified by shift assays using the cis-acting elements AP-1 and EGR-1 localized at the alpha-ENO promoter. Finally, we also demonstrated that IFN treatment of PBMC cause an increase in both, alpha-ENO expression on the cell surface and plasmin generation followed addition of exogenous plasminogen.

Plasmin Induces In Vivo Monocyte Recruitment through Protease-Activated Receptor-1–, MEK/ERK-, and CCR2-Mediated Signaling

“…Although Pla-induced signal transduction pathways have been analyzed in vitro in a few previous reports (19,21,23,24,31,33), the signaling pathways that govern Pla-induced cell migration in vivo have not been studied in detail. It has been shown that Plg/Pla activates ERK1/2 in fibroblasts (20,21,23,24), monocytes (31), and dendritic cells (33). We have previously shown that Plg/Pla activates the MEK/ERK pathway, leading to the expression of the transcription factors c-fos and Egr-1 (20), which in turn promotes a-enolase expression (23,24), an important Plg receptor that mediates monocyte recruitment in vivo (14).…”

“…1B) in a time-dependent manner. Because we have previously demonstrated that the MEK/ERK pathway is involved in Plg-induced gene expression in fibroblasts and monocytes (20,23,24), and it is known to be involved in cell motility (30), we wondered whether such pathway could underlie the Pla-induced migration in these cells. Interestingly, cell migration was associated with increased phosphorylation of ERK1/2 in both cell types (Fig.…”

“…We have previously demonstrated that the proinflammatory cytokine IFN-a increased the expression of the Plg receptor a-enolase on the surface of human monocytes with a consequent increase of Pla generation and proteolysis (23). Furthermore, IFN-a and Plg-induced expression of a-enolase was dependent on the MEK/ERK pathway (23,24).…”

“…Pla also triggers multiple signaling pathways such as JAK/STAT, p38 MAPK, and ERK1/2 (18)(19)(20) and it has been shown to activate protease-activated receptor-1 (PAR-1) in fibroblasts (21,22). We have previously demonstrated that the proinflammatory cytokine IFN-a increased the expression of the Plg receptor a-enolase on the surface of human monocytes with a consequent increase of Pla generation and proteolysis (23). Furthermore, IFN-a and Plg-induced expression of a-enolase was dependent on the MEK/ERK pathway (23,24).…”

Anti-Inflammatory Effects of the Activation of the Angiotensin-(1–7) Receptor, Mas, in Experimental Models of Arthritis

“…Western blot analysis for the Ang-(1-7) Mas receptor was performed, as described previously by Sousa et al (30), in periarticular tissues, which include connective soft tissues that surround bone and cartilage and also the synovial membrane, from AIA and control animals. A rabbit polyclonal anti-Mas Ab (Novus Biologicals, Littleton, CO) was used at the dilution of 1:1000.…”