Oxidative Modification of Nuclear Mitogen-activated Protein Kinase Phosphatase 1 Is Involved in Transforming Growth Factor β1-induced Expression of Plasminogen Activator Inhibitor 1 in Fibroblasts

Abstract

Transforming growth factor ␤ (TGF-␤) stimulates reactive oxygen species (ROS) production in various cell types, which mediates many of the effects of TGF-␤. The molecular mechanisms whereby TGF-␤ increases ROS production and ROS modulate the signaling processes of TGF-␤, however, remain poorly defined. In this study, we show that TGF-␤1 stimulates NADPH oxidase 4 (Nox4) expression and ROS generation in the nucleus of murine embryo fibroblasts (NIH3T3 cells). This is associated with an increase in protein thiol modification and inactivation of MAPK phosphatase 1 (MKP-1), a nuclear phosphatase. Furthermore, knockdown of MKP-1 using small interfering RNA enhances TGF-␤1-induced phosphorylation of JNK and p38 as well as the expression of plasminogen activator inhibitor 1 (PAI-1), a TGF-␤-responsive gene involved in the pathogenesis of many diseases. Knockdown of Nox4 with Nox4 small interfering RNA, on the other hand, reduces TGF-␤1-stimulated ROS production, p38 phosphorylation, and PAI-1 expression. TGF-␤ also increased the nuclear level of Nox4 protein as well as PAI-1 expression in human lung fibroblasts (CCL-210 cells), suggesting that TGF-␤ may induce PAI-1 expression by a similar mechanism in human lung fibroblasts. In summary, in this study we have identified nuclear MAPK phosphatase MKP-1 as a novel molecular target of ROS in TGF-␤ signaling pathways. Our data suggest that increased generation of ROS by Nox4 mediates TGF-␤1-induced PAI-1 gene expression at least in part through oxidative modification and inhibition of MKP-1 leading to a sustained activation of JNK and p38 MAPKs.

Anti–Human Neutrophil Antigen-3a Induced Transfusion-Related Acute Lung Injury in Mice by Direct Disturbance of Lung Endothelial Cells

“…51 In addition, induction of transforming growth factor β1 signaling pathway is known to be responsible for the generation of ROS in endothelial cells. 52 Accordingly, binding of anti-HNA-3a to the functional CTL2-P2 isoform, expressed on endothelial cells, may initiate signal transduction leading to ROS production. This intriguing hypothesis is the subject matter of our future work.…”

A 28-kDa Splice Variant of NADPH Oxidase-4 Is Nuclear-Localized and Involved in Redox Signaling in Vascular Cells

“…25 We, therefore, examined the effect of Nox4D on ERK1/2 phosphorylation. Cells infected with Nox4D adenovirus had significantly increased levels of phosphorylated ERK1/2 compared with βGal-infected control cells ( Figure 7A).…”

Hyaluronic Acid Promotes Angiogenesis by Inducing RHAMM-TGFβ Receptor Interaction via CD44-PKCδ

“…Snail is required for TGFβ-induced epithelial-mesenchymal transition (Kokudo et al, 2008), and functional blockade of Snail decreases the expression of PAI-1 in breast cancer cells and exerts a negative effect on cancer cell migration (FabreGuillevin et al, 2008). PAI-1 is induced by TGFβ (Liu et al, 2010) and TGF-β1 utilizes RHAMM to promote cell motility (Samuel et al, 1993). Histone deacetylase (HDAC), such as HDAC5, acts as a negative regulator of angiogenesis (Urbich et al, 2009).…”