Cigarette smoke particle-phase extract induces HO-1 expression in human tracheal smooth muscle cells: role of the c-Src/NADPH oxidase/MAPK/Nrf2 signaling pathway

Lin

Journal Cellular Physiology

et al. 2011

Self Cite

Cytosolic phospholipase A(2) (cPLA(2)) plays a pivotal role in mediating agonist-induced arachidonic acid (AA) release for prostaglandin (PG) synthesis during inflammation triggered by tumor necrosis factor-α (TNF-α). However, the mechanisms underlying TNF-α-induced cPLA(2) expression and PGE(2) synthesis in human tracheal smooth muscle cells (HTSMCs) remain unknown. Here, we report that TNF-α-induced cPLA(2) protein and mRNA expression, PGE(2) production, and phosphorylation of p42/p44 MAPK, p38 MAPK, and JNK1/2, which were attenuated by pretreatment with a ROS scavenger [N-acetyl-L-cysteine, (NAC)] and the inhibitors of NADPH oxidase [apocynin (APO) and diphenyleneiodonium chloride (DPI)], MEK1/2 (U0126), p38 MAPK (SB202190), and JNK1/2 (SP600125) or transfection with siRNA of Nox2, p47(phox) , MEK1, p42, p38, or JNK2. TNF-α-induced cPLA(2) expression was also inhibited by pretreatment with a selective NF-κB inhibitor [helenalin (HLN)] or transfection with dominant negative mutants of NF-κB inducing kinase (NIK) or IκB kinase (IKK)α/β. TNF-α-induced NF-κB translocation was blocked by pretreatment with NAC, DPI, APO, or HLN, but not by U0126, SB202190, or SP600125. In addition, pretreatment with curcumin (a p300 inhibitor) or transfection with p300 siRNA blocked cPLA(2) expression and PGE(2) synthesis induced by TNF-α. We further confirmed that p300 was associated with the cPLA(2) promoter which was dynamically linked to histone H4 acetylation stimulated by TNF-α, determined by chromatin immunoprecipitation assay. Association of p300 and histone H4 to cPLA(2) promoter was inhibited by U0126, SB202190, and SP600125. These results suggested that in HTSMCs, activation of p47(phox) , MAPKs, NF-κB, and p300 is essential for TNF-α-induced cPLA(2) expression and PGE(2) release.

Section: Tnf-a Induces Cpla 2 Expression and Pge 2 Releasesupporting

confidence: 57%

Activation and induction of cytosolic phospholipase A₂ by TNF‐α mediated through Nox2, MAPKs, NF‐κB, and p300 in human tracheal smooth muscle cells

Lin

Journal Cellular Physiology

et al. 2011

Self Cite

Antioxidants & Redox Signaling

“…Under the Nrf2 activation, it dissociates from Kelch-like ECHassociated protein 1 (Keap1) and translocates into the nucleus, where it binds ARE (18). Different pathways may activate Nrf2, including PI3K/Akt and MAPKs (6,13,38). We found that EP can activate Nrf2 by enhancing Nrf2 nuclear accumulation and the ARE-luciferase activity.…”

mentioning

confidence: 82%

Ethyl Pyruvate Induces Heme Oxygenase-1 Through p38 Mitogen-Activated Protein Kinase Activation by Depletion of Glutathione in RAW 264.7 Cells and Improves Survival in Septic Animals

Jang

Kim

Tsoyi

et al. 2012

Aims: We investigated the molecular mechanism by which ethyl pyruvate (EP) induces heme oxygenase-1 (HO-1) in RAW 264.7 cells and its effect on survival rate in cecal ligation and puncture (CLP)-induced wild-type (WT) and HO-1 knockout (HO-1 -/ -) septic mice. Results: EP induced HO-1 in a dose-and time-dependent manner, which was mediated through p38 mitogen-activated protein kinase (MAPK) and NF-E2-related factor 2 (Nrf2) signaling cascade in RAW 264.7 cells. EP significantly inhibited the lipopolysaccharide (LPS)-stimulated inducible nitric oxide synthase (iNOS) expression and high-mobility group box 1 (HMGB1) release in RAW 264.7 cells. The inhibitory effect of EP on LPS-stimulated iNOS expression and HMGB1 release was reversed by transfection with siHO-1RNA in RAW 264.7 cells, but EP failed to reduce them in HO-1 -/ -peritoneal macrophages treated with LPS. Moreover, treatment of cells with glutathione ethyl ester (GSH-Et), SB203580 (p38 MAPK inhibitor), siHO-1, or p38-siRNA transfection inhibited anti-inflammatory effect of EP. Interestingly, both HO-1 induction and phosphorylation of p38 by EP were reversed by GSH-Et, and antioxidant redox elementluciferase activity by EP was reversed by SB203580 in LPS-activated cells. EP increased survival and decreased serum HMGB1 in CLP-WT mice, whereas it did not increase survival or decrease circulating HMGB1 in HO-1 -/ -CLP-mice. Innovation and Conclusion: Our work provides new insights into the understanding the molecular mechanism by showing that EP induces HO-1 through a p38 MAPK-and NRF2-dependent pathway by decreasing GSH cellular levels. We conclude that EP inhibits proinflammatory response to LPS in macrophages and increases survival in CLP-induced septic mice by upregulation of HO-1 level, in which p38 MAPK and Nrf2 play an important role. Antioxid. Redox Signal. 17, 878-889.

“…HOX-1 up-regulation has also been marked to be JNK1/2 and Src dependent in arsenitetreated murine embryonic fibroblasts (69). Transfecting with small interfering RNA for Src, p38, ERK1, and JNK2 also confirmed all the aforementioned mediator involvement in cigarette smoke particle-induced HOX-1 up-regulation in human tracheal smooth muscle cells (70). One should point out, however, that reports also exist describing p38-MAPK and MSK1 involvement in HOX-1 regulation by various stimuli (28, 71).…”

Section: Discussionmentioning

confidence: 64%

Insulin-Induced Oxidative Stress Up-Regulates Heme Oxygenase-1 via Diverse Signaling Cascades in the C2 Skeletal Myoblast Cell Line

et al. 2011

Impaired insulin sensitivity (insulin resistance) is a common denominator in many metabolic disorders, exerting pleiotropic effects on skeletal muscle, liver, and adipose tissue function. Heme oxygenase-1 (HOX-1), the rate-limiting enzyme in heme catabolism, has recently been shown to confer an antidiabetic effect while regulating cellular redox-buffering capacity. Therefore, in the present study, we probed into the mechanisms underlying the effect of insulin on HOX-1 in C2 skeletal myoblasts. Hence, insulin was found to suppress C2 myoblasts viability via stimulation of oxidative stress, with HOX-1 counteracting this action. Insulin induced HOX-1 expression in a time-and dose-dependent manner, an effect attenuated by selective inhibitors of ERK1/2 (PD98059), Src (4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d] pyrimidine), and c-Jun terminal kinases 1 and 2 (SP600125) pathways. Furthermore, nuclear factor-B role in insulin-induced HOX-1 up-regulation was verified, with ERK1/2, Src, and c-Jun terminal kinases 1 and 2 mediating p65-nuclear factor-B subunit phosphorylation. Overall, our novel findings highlight for the first time the transduction mechanisms mediating HOX-1 induction in insulin-treated C2 myoblasts. This effect was established to be cell type specific because insulin failed to promote HOX-1 expression in HepG2 hepatoma cells. Deciphering the signaling networks involved in insulin-stimulated HOX-1 up-regulation is of prominent significance because it may potentially contribute to elucidation of the mechanisms involved in associated metabolic pathologies. (Endocrinology 152: 1274 -1283, 2011)