Up-regulation of heme oxygenase-1 expression through the Rac1/NADPH oxidase/ROS/p38 signaling cascade mediates the anti-inflammatory effect of 15-deoxy-Δ12,14-prostaglandin J2 in murine macrophages

Department of Biochemistry, College of Natural Sciences, Kangwon National University, Chuncheon 200-701, Republic of Korea.
FEBS Letters (Impact Factor: 3.17). 04/2008; 582(6):861-8. DOI: 10.1016/j.febslet.2008.02.012
Source: PubMed


We investigated the signaling pathway that leads to the expression of heme oxygenase-1 (HO-1) in murine macrophages in response to 15-deoxy-delta 12,14-prostaglandin J2 (15dPGJ2). 15dPGJ2 caused dose- and time-dependent activation of Rac1, followed by a transient increase in reactive oxygen species (ROS) via NADPH oxidase, which leads to downstream activation of p38 kinase. Inhibition of 15dPGJ2-dependent HO-1 expression significantly attenuated suppression by 15dPGJ2 of LPS-induced iNOS expression and subsequent production of nitric oxide (NO). Our findings strongly suggest that 15dPGJ2 exerts its anti-inflammatory activity through the Rac1-NADPH oxidase-ROS-p38 signaling to the up-regulation of HO-1 in an in vitro inflammation model.

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    • "However, the exact mechanism, by which 15d-PGJ 2 acts, is still unknown in chondrocytes. Previous reports demonstrated that, in the micromolar range, 15d-PGJ 2 induces ROS production by murine macrophages [32], human lymphocytes [33], or HepG2 hepatoma cell line [34]. However, such oxidative stress may depend on cell type since no ROS production was observed in the PCCL3 thyrocyte cell line exposed to 15d-PGJ 2 [47]. "
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    ABSTRACT: The inhibitory effect of 15-deoxy-Δ(12, 14)-prostaglandin J2 (15d-PGJ2) on pro-inflammatory genes expression has been extensively documented and frequently ascribed to its ability to prevent NF-κB pathway activation. We and others have previously demonstrated that it was frequently independent of the peroxisome proliferator activated receptor (PPAR)γ activation. Here, we provide evidence that induction of intracellular Heat Shock Protein (HSP)70 by oxidative stress is an additional regulatory loop supporting the anti-inflammatory effect of 15d-PGJ2 in chondrocytes. Using real-time quantitative PCR and western blotting, we showed that 15d-PGJ2 stimulated HSP70, but not HSP27 expression while increasing oxidative stress as measured by spectrofluorimetry and confocal spectral imaging. Using N-acetylcysteine (NAC) as an antioxidant, we demonstrated further that oxidative stress was thoroughly responsible for the increased expression of HSP70. Finally, using HSP70 antisense strategy, we showed that the inhibitory effect of 15d-PGJ2 on IL-1-induced activation of NF-κB pathway, COX-2 and mPGES-1 expression, and PGE2 synthesis was partly supported by HSP70. These data provide a new anti-inflammatory mechanism to support the PPARγ-independent effect of 15d-PGJ2 in chondrocyte and suggest a possible feedback regulatory loop between oxidative stress and inflammation via intracellular HSP70 up-regulation. This cross-talk is consistent with 15d-PGJ2 as a putative negative regulator of the inflammatory reaction.
    Free Radical Biology and Medicine 08/2014; 76. DOI:10.1016/j.freeradbiomed.2014.07.028 · 5.74 Impact Factor
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    • "Additionally, 15dPGJ2 is able to activate cytoprotective mechanisms, such as the induction of HO-1 expression, in an NF-κB-independent fashion [30]. Similar results have been described by our group in human lymphocytes [32], and by other researchers in murine macrophages [65]. Therefore, accumulating evidence of 15dPGJ2 pro-inflammatory actions [22], [23], [66], [67] taken altogether makes its anti-inflammatory properties increasingly controversial [24]–[27], [31]. "
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    PLoS ONE 10/2012; 7(10):e42195. DOI:10.1371/journal.pone.0042195 · 3.23 Impact Factor
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    • "Our observations showed that only 15Δ-PGJ2 stimulated L6 cell proliferation while PGF2α and PGE2 were found to be without effect. Evidence supporting the role of 15Δ-PGJ2 in the resolution phase of inflammation is growing [45-47]; furthermore, it was shown to stimulate human fetal foreskin fibroblast proliferation [22]. In our model, the stimulating effect induced by 15Δ-PGJ2 was very significant and further underlines the importance of COX-2 activity. "
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    ABSTRACT: Mast cells contribute to tissue repair in fibrous tissues by stimulating proliferation of fibroblasts through the release of tryptase which activates protease-activated receptor-2 (PAR-2). The possibility that a tryptase/PAR-2 signaling pathway exists in skeletal muscle cell has never been investigated. The aim of this study was to evaluate whether tryptase can stimulate myoblast proliferation and determine the downstream cascade. Proliferation of L6 rat skeletal myoblasts stimulated with PAR-2 agonists (tryptase, trypsin and SLIGKV) was assessed. The specificity of the tryptase effect was evaluated with a specific inhibitor, APC-366. Western blot analyses were used to evaluate the expression and functionality of PAR-2 receptor and to assess the expression of COX-2. COX-2 activity was evaluated with a commercial activity assay kit and by measurement of PGF2α production. Proliferation assays were also performed in presence of different prostaglandins (PGs). Tryptase increased L6 myoblast proliferation by 35% above control group and this effect was completely inhibited by APC-366. We confirmed the expression of PAR-2 receptor in vivo in skeletal muscle cells and in satellite cells and in vitro in L6 cells, where PAR-2 was found to be functional. Trypsin and SLIGKV increased L6 cells proliferation by 76% and 26% above control, respectively. COX-2 activity was increased following stimulation with PAR-2 agonist but its expression remained unchanged. Inhibition of COX-2 activity by NS-398 abolished the stimulation of cell proliferation induced by tryptase and trypsin. Finally, 15-deoxy-Δ-12,14-prostaglandin J2 (15Δ-PGJ2), a product of COX-2-derived prostaglandin D2, stimulated myoblast proliferation, but not PGE2 and PGF2α. Taken together, our data show that tryptase can stimulate myoblast proliferation and this effect is part of a signaling cascade dependent on PAR-2 activation and on the downstream activation of COX-2.
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