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HO-1 induction by CO-RM2 attenuates TNF-α-induced cytosolic phospholipase A2 expression via inhibition of PKCα-dependent NADPH oxidase/ROS and NF-κB.

Chi PL, Liu CJ, Lee IT, Chen YW, Hsiao LD, Yang CM - Mediators Inflamm. (2014)

Bottom Line: Here, we reported that TNF-α-induced cPLA2 expression was mediated through TNFR1/PKCα-dependent signaling pathways, including NADPH oxidase (NOX) activation/ROS production and NF-κB activation.CO-RM2 significantly suppressed TNF-α-induced cPLA2 expression by inhibiting the ROS generation and the phosphorylation of NF-κB p65 and IKK α/β, but not the phosphorylation of p38 MAPK and JNK1/2.These results were further confirmed by a ChIP assay to detect the NF-κB DNA-binding activity.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology and Pharmacology and Health Aging Research Center, College of Medicine, Chang Gung University, Kwei-San, Tao-Yuan 333, Taiwan.

ABSTRACT
Rheumatoid arthritis (RA) is characterized by chronic inflammatory infiltration of the synovium and elevation of proinflammatory cytokines. Cytosolic phospholipase A2 (cPLA2) is involved in the development of inflammatory diseases. Heme oxygenase-1 (HO-1) has been shown to possess anti-inflammatory properties. The objective of the study was to investigate the detailed mechanisms of TNF-α-induced cPLA2 expression and to determine whether carbon monoxide releasing molecule-2 (CO-RM2) suppresses TNF-α-induced expression of NF-κB-related proinflammatory genes, including cPLA2, via HO-1 induction in RA synovial fibroblasts (RASFs). Here, we reported that TNF-α-induced cPLA2 expression was mediated through TNFR1/PKCα-dependent signaling pathways, including NADPH oxidase (NOX) activation/ROS production and NF-κB activation. CO-RM2 significantly suppressed TNF-α-induced cPLA2 expression by inhibiting the ROS generation and the phosphorylation of NF-κB p65 and IKK α/β, but not the phosphorylation of p38 MAPK and JNK1/2. These results were further confirmed by a ChIP assay to detect the NF-κB DNA-binding activity. Our results demonstrated that induction of HO-1 by CO-RM2 exerted anti-inflammatory and antioxidant effects which were required in concert to prevent the activation of NF-κB leading to induction of various inflammatory genes implicated in the pathogenesis of RA.

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Related in: MedlinePlus

Effects of CORM-2 on the TNF-α-induced cPLA2 expression. TNF-α stimulated NF-κB activation through TNFR1/PKCα/IKKα/β, and p38 MAPK-, JNK-1/2-dependent NOX/ROS pathways resulting in cPLA2 expression in RASFs. The downregulation of TNF-α-induced cPLA2 expression by CORM-2 is mediated by the reduction in NF-κB transcriptional activity and decrease in generation of NOX/ROS.
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fig8: Effects of CORM-2 on the TNF-α-induced cPLA2 expression. TNF-α stimulated NF-κB activation through TNFR1/PKCα/IKKα/β, and p38 MAPK-, JNK-1/2-dependent NOX/ROS pathways resulting in cPLA2 expression in RASFs. The downregulation of TNF-α-induced cPLA2 expression by CORM-2 is mediated by the reduction in NF-κB transcriptional activity and decrease in generation of NOX/ROS.

Mentions: Inflammation and oxidative stress play a key role in the pathogenesis of RA. cPLA2 may represent a pathogenic link between the generation of eicosanoids and the production of inflammatory molecules in the development of arthritis [5]. CO-RM has been shown to perform anti-inflammatory effects in various cell types [11, 16, 32]. Thus, in this study, we attempted to investigate the protective mechanisms of CORM-2 in TNF-α-challenged RASFs and ICR mice. Here, we demonstrated that TNF-α-induced cPLA2 expression was regulated via a complex of TNFR1/PKCα that triggered the activation of p38 MAPK- and JNK1/2-dependent NOX/ROS generation, leading to activation of NF-κB in RASFs. Moreover, we found that CORM-2 hampered p65 recruitment to the promoter of cPLA2 through the attenuation of IKKα/β and p65 phosphorylation and ROS production, leading to the suppression of TNF-α-induced cPLA2 expression (Figure 8).


HO-1 induction by CO-RM2 attenuates TNF-α-induced cytosolic phospholipase A2 expression via inhibition of PKCα-dependent NADPH oxidase/ROS and NF-κB.

Chi PL, Liu CJ, Lee IT, Chen YW, Hsiao LD, Yang CM - Mediators Inflamm. (2014)

Effects of CORM-2 on the TNF-α-induced cPLA2 expression. TNF-α stimulated NF-κB activation through TNFR1/PKCα/IKKα/β, and p38 MAPK-, JNK-1/2-dependent NOX/ROS pathways resulting in cPLA2 expression in RASFs. The downregulation of TNF-α-induced cPLA2 expression by CORM-2 is mediated by the reduction in NF-κB transcriptional activity and decrease in generation of NOX/ROS.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3927740&req=5

fig8: Effects of CORM-2 on the TNF-α-induced cPLA2 expression. TNF-α stimulated NF-κB activation through TNFR1/PKCα/IKKα/β, and p38 MAPK-, JNK-1/2-dependent NOX/ROS pathways resulting in cPLA2 expression in RASFs. The downregulation of TNF-α-induced cPLA2 expression by CORM-2 is mediated by the reduction in NF-κB transcriptional activity and decrease in generation of NOX/ROS.
Mentions: Inflammation and oxidative stress play a key role in the pathogenesis of RA. cPLA2 may represent a pathogenic link between the generation of eicosanoids and the production of inflammatory molecules in the development of arthritis [5]. CO-RM has been shown to perform anti-inflammatory effects in various cell types [11, 16, 32]. Thus, in this study, we attempted to investigate the protective mechanisms of CORM-2 in TNF-α-challenged RASFs and ICR mice. Here, we demonstrated that TNF-α-induced cPLA2 expression was regulated via a complex of TNFR1/PKCα that triggered the activation of p38 MAPK- and JNK1/2-dependent NOX/ROS generation, leading to activation of NF-κB in RASFs. Moreover, we found that CORM-2 hampered p65 recruitment to the promoter of cPLA2 through the attenuation of IKKα/β and p65 phosphorylation and ROS production, leading to the suppression of TNF-α-induced cPLA2 expression (Figure 8).

Bottom Line: Here, we reported that TNF-α-induced cPLA2 expression was mediated through TNFR1/PKCα-dependent signaling pathways, including NADPH oxidase (NOX) activation/ROS production and NF-κB activation.CO-RM2 significantly suppressed TNF-α-induced cPLA2 expression by inhibiting the ROS generation and the phosphorylation of NF-κB p65 and IKK α/β, but not the phosphorylation of p38 MAPK and JNK1/2.These results were further confirmed by a ChIP assay to detect the NF-κB DNA-binding activity.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology and Pharmacology and Health Aging Research Center, College of Medicine, Chang Gung University, Kwei-San, Tao-Yuan 333, Taiwan.

ABSTRACT
Rheumatoid arthritis (RA) is characterized by chronic inflammatory infiltration of the synovium and elevation of proinflammatory cytokines. Cytosolic phospholipase A2 (cPLA2) is involved in the development of inflammatory diseases. Heme oxygenase-1 (HO-1) has been shown to possess anti-inflammatory properties. The objective of the study was to investigate the detailed mechanisms of TNF-α-induced cPLA2 expression and to determine whether carbon monoxide releasing molecule-2 (CO-RM2) suppresses TNF-α-induced expression of NF-κB-related proinflammatory genes, including cPLA2, via HO-1 induction in RA synovial fibroblasts (RASFs). Here, we reported that TNF-α-induced cPLA2 expression was mediated through TNFR1/PKCα-dependent signaling pathways, including NADPH oxidase (NOX) activation/ROS production and NF-κB activation. CO-RM2 significantly suppressed TNF-α-induced cPLA2 expression by inhibiting the ROS generation and the phosphorylation of NF-κB p65 and IKK α/β, but not the phosphorylation of p38 MAPK and JNK1/2. These results were further confirmed by a ChIP assay to detect the NF-κB DNA-binding activity. Our results demonstrated that induction of HO-1 by CO-RM2 exerted anti-inflammatory and antioxidant effects which were required in concert to prevent the activation of NF-κB leading to induction of various inflammatory genes implicated in the pathogenesis of RA.

Show MeSH
Related in: MedlinePlus