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Title: 15-Deoxy-Δ12,14-prostaglandin J₂ modulates manganese-induced activation of the NF-κB, Nrf2, and PI3K pathways in astrocytes.

Authors: Lee, Eunsook; Yin, Zhaobao; Sidoryk-Węgrzynowicz, Marta; Jiang, Haiyan; Aschner, Michael

Published In Free Radic Biol Med, (2012 Mar 15)

Abstract: Excessive exposure to manganese (Mn) increases levels of oxidative stressors and proinflammatory mediators, such as cyclooxygenase-2 and prostaglandin E(2). Mn also activates nuclear factor-κB (NF-κB), an important mediator of inflammation. The signaling molecule 15-deoxy-Δ12,14-prostaglandin J(2) (15 d-PGJ(2)) is an anti-inflammatory prostaglandin. Here, we tested the hypothesis that 15 d-PGJ(2) modulates Mn-induced activation of astrocytic intracellular signaling, including NF-κB and nuclear factor erythroid 2-related factor (Nrf2), a master regulator of antioxidant transcriptional responses. The results establish that 15 d-PGJ(2) suppresses Mn-induced NF-κB activation by interacting with several signaling pathways. The PI3K/Akt pathway, which is upstream of NF-κB, plays a role in this activation, because (i) pretreatment with 15 d-PGJ(2) (10 μM for 1h) significantly (p<0.01) inhibited Mn (500 μM)-induced PI3K/Akt activation and (ii) inhibition of the PI3K/Akt pathway with LY29004 significantly (p<0.05) decreased NF-κB activation. 15 d-PGJ(2) also significantly (p<0.05) attenuated Mn-induced astrocytic NF-κB activation by inhibiting the Mn-induced phosphorylation of IκB kinase and subsequent IκB-α degradation. Because Mn-induced oxidative stress is also associated with Nrf2 activation, additional studies addressed the ability of 15 d-PGJ(2) to modulate the Nrf2 pathway. 15 d-PGJ(2) significantly (p<0.01) increased Nrf2 expression in whole-cell lysates. Consistent with its pro-oxidant properties, Mn also increased Nrf2 expression. Nevertheless, cotreatment of whole-cell lysates with both Mn and 15 d-PGJ(2) partially suppressed (p<0.01) the 15 d-PGJ(2)-induced increase in astrocytic Nrf2 protein expression. Mn treatment also decreased (p<0.001) expression of DJ-1, a Parkinson disease-associated protein and a stabilizer of Nrf2, and 15 d-PGJ(2) attenuated Mn-induced astrocytic inhibition of DJ-1 expression. Collectively, these results demonstrate that 15d-PGJ(2) exerts a protective effect in astrocytes against Mn-induced inflammation and oxidative stress by modulating the activation of the NF-κB and Nrf2 signaling pathways.

PubMed ID: 22245093 Exiting the NIEHS site

MeSH Terms: Animals; Astrocytes/drug effects*; Astrocytes/metabolism; Astrocytes/pathology; Cells, Cultured; Chromones/pharmacology; Cytoprotection/drug effects; Gene Expression Regulation/drug effects; Intracellular Signaling Peptides and Proteins/genetics; Intracellular Signaling Peptides and Proteins/metabolism*; Manganese/metabolism; Morpholines/pharmacology; NF-E2-Related Factor 2/genetics; NF-E2-Related Factor 2/metabolism*; NF-kappa B/metabolism; Oncogene Proteins/genetics; Oncogene Proteins/metabolism*; Oxidative Stress/drug effects; Parkinson Disease/drug therapy; Parkinson Disease/metabolism*; Phosphatidylinositol 3-Kinases/antagonists & inhibitors; Prostaglandin D2/analogs & derivatives*; Prostaglandin D2/pharmacology; Protein Deglycase DJ-1; Rats; Rats, Sprague-Dawley; Signal Transduction/drug effects; Transcriptional Activation/drug effects

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Last Reviewed: October 07, 2024