scholarly journals Induction of HO-1 by Mevastatin Mediated via a Nox/ROS-Dependent c-Src/PDGFRα/PI3K/Akt/Nrf2/ARE Cascade Suppresses TNF-α-Induced Lung Inflammation

2020 ◽  
Vol 9 (1) ◽  
pp. 226 ◽  
Author(s):  
Chih-Chung Lin ◽  
Wei-Ning Lin ◽  
Rou-Ling Cho ◽  
Chien-Chung Yang ◽  
Yi-Cheng Yeh ◽  
...  

Background: Mevastatin (MVS), a 3-hydroxy-3-methylglutaryl coenzyme, a reductase (HMG-CoA) inhibitor, has anti-inflammatory effects potentially via up-regulation of heme oxygenase-1 (HO-1). However, the mechanisms underlying MVS-induced HO-1 expression remain largely unknown in human pulmonary alveolar epithelial cells (HPAEpiCs). Methods: HO-1 and intercellular adhesion molecule (ICAM)-1 expression were determined using real-time PCR, Western blotting, and promoter reporter analyses. The signaling components were investigated using pharmacological inhibitors or specific small interfering RNA (siRNA)s. Interaction between Nrf2 and the antioxidant response element (ARE) binding site for the HO-1 promoter was determined by chromatin immunoprecipitation (ChIP) assay. Results: Upregulation of HO-1 by MVS attenuated the tumor necrosis factor (TNF)-α-stimulated ICAM-1 expression associated with THP-1 adhesion to HPAEpiCs. These inhibitory effects of HO-1 were reversed by tin protoporphyrin (SnPP)IX or by transfection with HO-1 siRNA. MVS-induced HO-1 expression was mediated via NADPH oxidase (Nox)-derived reactive oxygen species (ROS) generation. Activation of Nox2/ROS further stimulated the phosphorylation of p47phox, proto-oncogene tyrosine-protein kinase (c-Src), platelet-derived growth factor receptor (PDFGR)α, protein kinase B (Akt), and Nrf2, which were inhibited by siRNAs. Pretreatment with pharmacological inhibitors, including diphenyleneiodonium (DPI), apocynin (APO), N-acetyl-L-cysteine (NAC), PP1, AG1296, or LY294002, reduced the MVS-activated Nrf2 nuclear-translocation binding to the ARE on the HO-1 promoter. Conclusions: MVS-induced HO-1 is, at least in part, mediated through a p47phox/Nox2/ROS-dependent activation of c-Src/PDGFRα/PI3K/Akt-regulated Nrf2/ARE axis and suppresses the TNF-α-mediated inflammatory responses in HPAEpiCs.

2019 ◽  
Vol 8 (4) ◽  
pp. 436 ◽  
Author(s):  
Chih-Chung Lin ◽  
Li-Der Hsiao ◽  
Rou-Ling Cho ◽  
Chuen-Mao Yang

The upregulation of heme oxygenase-1 (HO-1) by the carbon monoxide-releasing molecule (CORM)-2 may be mediated through the activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidases [Nox] and reactive oxygen species (ROS) generation, which could provide cytoprotection against various cellular injuries. However, the detailed mechanisms of CORM-2-induced HO-1 expression in human pulmonary alveolar epithelial cells (HPAEpiCs) remain largely unknown. Therefore, we dissected the mechanisms underlying CORM-2-induced HO-1 expression in HPAEpiCs. We found that the administration of mice with CORM-2 attenuated the tumor necrosis factor-alpha (TNF-α)-induced intercellular adhesion molecule-1 (ICAM-1) expression and leukocyte count as revealed by immunohistochemical staining, western blot, real-time polymerase chain reaction (PCR), and cell count. Furthermore, TNF-α-induced ICAM-1 expression associated with monocyte adhesion to HPAEpiCs was attenuated by infection with adenovirus (adv)-HO-1 or incubation with CORM-2. These inhibitory effects of HO-1 were reversed by pretreatment with hemoglobin (Hb). Moreover, CORM-2-induced HO-1 expression was mediated via the phosphorylation of p47phox, c-Src, epidermal growth factor receptor (EGFR), Akt, and NF-E2-related factor 2 (Nrf2), which were inhibited by their pharmacological inhibitors, including diphenyleneiodonium (DPI) or apocynin (APO), ROS [N-acetyl-L-cysteine (NAC)], PP1, AG1478, PI3K (LY294002), or Akt (SH-5), and small interfering RNAs (siRNAs). CORM-2-enhanced Nrf2 expression, and anti-oxidant response element (ARE) promoter activity was also inhibited by these pharmacological inhibitors. The interaction between Nrf2 and AREs was confirmed with a chromatin immunoprecipitation (ChIP) assay. These findings suggest that CORM-2 increases the formation of the Nrf2 and AREs complex and binds with ARE-binding sites via Src, EGFR, and PI3K/Akt, which further induces HO-1 expression in HPAEpiCs. Thus, the HO-1/CO system might suppress TNF-α-mediated inflammatory responses and exert a potential therapeutic strategy in pulmonary diseases.


2020 ◽  
Author(s):  
XiaoMei Huang ◽  
ZeXun Mo ◽  
YuJun Li ◽  
Hua He ◽  
KangWei Wang ◽  
...  

Abstract Background Nuclear factor kappa-B (NF-κB) activation increased the expression of cytokines and further lead to lung injury was considered the main mechanism of acute lung injury (ALI). Here, we focus on exploring the potential regulatory mechanism between long noncoding RNA (LncRNA) HOX transcript antisense RNA (HOTAIR) and NF-κB on LPS-induced ALI. Methods A549 cells were then divided into 4 groups: HOTAIR group, NC group, si-HOTAIR group and si-NC group. These 4 groups were then treated with 1μg/mL lipopolysaccharides (LPS) or without LPS at 37°C for 24 h. The expression level of cytokines (tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6) and LncRNA HOTAIR were evaluated by quantitative Real Time Polymerase Chain Reaction (qRT-PCR) and Enzyme-linked immunosorbent assay (ELISA). Western Blot analysis was adopted for evaluating the level of p-IκBα/IκBα and p-p65/p65. Nuclear translocation of p65 was observed by immunofluorescence staining. Results qRT-PCR and ELISA assay showed that the expression of cytokines (IL-1β, IL-6 and TNF-α) and inflammatory gene HOTAIR was remarkably increased with LPS treatment (p < 0.01). Over-expression of HOTAIR significantly increased the expression of cytokines (including IL-1β, IL-6 and TNF-α) and NF-κB pathway associated proteins (including p-IκBα/IκBα and p-p65/p65), while knockdown of HOTAIR had the opposite effect (p < 0.01). The immunofluorescence assay showed that the level of p65 in the nucleus was significantly higher in the HOTAIR group and significantly lowers in the si-HOTAIR group (p < 0.01). Conclusion HOTAIR may play a pro-inflammatory response through NF-κB pathway in LPS-induced ALI, which may provide a perspective for further understanding the pathogenic mechanism of ALI.


2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Seung Eun Lee ◽  
See-Hyoung Park ◽  
Ju Ah Yoo ◽  
Kitae Kwon ◽  
Ji Woong Kim ◽  
...  

Background. Benzo[a]pyrene (B[a]P), a polycyclic aromatic hydrocarbon present in the atmosphere, has cytotoxic and carcinogenic effects. There have been no reports to demonstrate involvement of Clematis apiifolia DC. extract (CAE) in B[a]P-induced effects. This study was conducted to investigate the effect of CAE on B[a]P-induced effects and to elucidate its mechanism of action in HaCaT human keratinocytes. CAE inhibited aryl hydrocarbon receptor (AhR) signaling by decreasing both XRE reporter activity and expression of cytochrome P450 1A1 (CYP1A1) induced by B[a]P treatment in HaCaT cells. We also found that B[a]P-induced nuclear translocation of AhR and production of reactive oxygen species (ROS) and proinflammatory cytokines were attenuated by CAE treatment. CAE treatment suppressed B[a]P-induced phosphorylation of Src (Tyr416). In addition, dasatinib, a Src inhibitor, also inhibited B[a]P-induced nuclear translocation of AhR, similar to CAE treatment. In addition, CAE activated antioxidant response element (ARE) signaling by increasing ARE luciferase reporter activity and expression of ARE-dependent genes such as nuclear factor (erythroid-derived 2)-like 2 (Nrf2), NAD(P)H dehydrogenase [quinone] 1 (NQO1), and heme oxygenase-1 (HO-1). Nuclear translocation of Nrf2 by CAE was demonstrated by Western blot analysis and immunocytochemistry. The effects of CAE on ARE signaling were attenuated by knockdown of the Nrf2 gene. Inhibition of AhR signaling and activation of antioxidant activity by CAE operated in a reciprocally independent manner as evidenced by AhR and Nrf2 siRNA experiments. These findings indicate that CAE exerts protective effects against B[a]P by inhibiting AhR signaling and activating Nrf2-mediated signaling, suggesting its potential in protection from harmful B[a]P-containing pollutants.


Molecules ◽  
2019 ◽  
Vol 24 (18) ◽  
pp. 3394 ◽  
Author(s):  
Seon Min Lee ◽  
Na-Hyun Kim ◽  
Sangbum Lee ◽  
Yun Na Kim ◽  
Jeong-Doo Heo ◽  
...  

Crohn’s disease (CD) and ulcerative colitis (UC), collectively referred to as inflammatory bowel disease (IBD), are autoimmune diseases characterized by chronic inflammation within the gastrointestinal tract. Debromohymenialdisine is an active pyrrole alkaloid that is well known to serve as a stable and effective inhibitor of Chk2. In the present study, we attempted to investigate the anti-inflammatory properties of (10Z)-debromohymenialdisine (1) isolated from marine sponge Stylissa species using an intestinal in vitro model with a transwell co-culture system. The treatment with 1 attenuated the production and gene expression of lipopolysaccharide (LPS)-induced Interleukin (IL)-6, IL-1β, prostaglandin E2 (PGE2), and tumor necrosis factor-α in co-cultured THP-1 macrophages at a concentration range of 1–5 μM. The protein expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 were down-regulated in response to the inhibition of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) translocation into the nucleus in cells. In addition, we observed that 1 markedly promoted the nuclear translocation of nuclear factor erythroid 2 related factor 2 (Nrf2) and subsequent increase of heme oxygenase-1 (HO-1) expression. These findings suggest the potential use of 1 as a pharmaceutical lead in the treatment of inflammation-related diseases including IBD.


2016 ◽  
Vol 310 (7) ◽  
pp. L639-L657 ◽  
Author(s):  
Rou-Ling Cho ◽  
Chien-Chung Yang ◽  
I-Ta Lee ◽  
Chih-Chung Lin ◽  
Pei-Ling Chi ◽  
...  

Upregulation of intercellular adhesion molecule-1 (ICAM-1) is frequently implicated in lung inflammation. Lipopolysaccharide (LPS) has been shown to play a key role in inflammation via adhesion molecule induction and then causes lung injury. However, the mechanisms underlying LPS-induced ICAM-1 expression in human pulmonary alveolar epithelial cells (HPAEpiCs) remain unclear. We showed that LPS induced ICAM-1 expression in HPAEpiCs, revealed by Western blotting, RT-PCR, real-time PCR, and promoter assay. Pretreatment with the inhibitor of c-Src (protein phosphatase-1, PP1), reactive oxygen species (ROS) (Edaravone), NADPH oxidase (apocynin and diphenyleneiodonium chloride), EGFR (AG1478), PDGFR (AG1296), phosphatidylinositol-3-kinase (PI3K) (LY294002), MEK1/2 (U0126), or NF-κB (Bay11-7082) and transfection with siRNAs of c-Src, EGFR, PDGFR, Akt, p47 phox, Nox2, Nox4, p42, and p65 markedly reduced LPS-induced ICAM-1 expression and monocyte adherence to HPAEpiCs challenged with LPS. In addition, we established that LPS stimulated phosphorylation of c-Src, EGFR, PDGFR, Akt, or p65, which was inhibited by pretreatment with their respective inhibitors. LPS induced Toll-like receptor 4 (TLR4), MyD88, TNF receptor-associated factor 6 (TRAF6), c-Src, p47 phox, and Rac1 complex formation 2, which was attenuated by transfection with c-Src or TRAF6 siRNA. Furthermore, LPS markedly enhanced NADPH oxidase activation and intracellular ROS generation, which were inhibited by PP1. We established that LPS induced p42/p44 MAPK activation via a c-Src/NADPH oxidase/ROS/EGFR, PDGFR/PI3K/Akt-dependent pathway in these cells. Finally, we observed that LPS significantly enhanced NF-κB and IκBα phosphorylation, NF-κB translocation, and NF-κB promoter activity, which were inhibited by PP1, Edaravone, apocynin, diphenyleneiodonium chloride, AG1478, AG1296, LY294002 , or U0126. These results demonstrated that LPS induces p42/p44 MAPK activation mediated through the TLR4/MyD88/TRAF6/c-Src/NADPH oxidase/ROS/EGFR, PDGFR/PI3K/Akt pathway, which in turn initiates the activation of NF-κB and ultimately induces ICAM-1 expression in HPAEpiCs.


Gut ◽  
1998 ◽  
Vol 42 (6) ◽  
pp. 779-787 ◽  
Author(s):  
C Jobin ◽  
C Hellerbrand ◽  
L L Licato ◽  
D A Brenner ◽  
R B Sartor

Background/aims—The gene promoter for the intercellular adhesion molecule ICAM-1 possesses binding sites for several transcriptional factors, including nuclear factor κB (NF-κB). The role of NF-κB in ICAM-1 gene regulation was therefore examined by using different proteasome inhibitors in tumour necrosis factor α (TNF-α) stimulated IEC-6 rat intestinal epithelial cells.Methods—ICAM-1 expression was analysed by enzyme linked immunosorbent assay (ELISA), reverse transcriptase polymerase chain reaction, and immunohistochemistry. Steady state levels of cytoplasmic IκB protein were evaluated by western blot, and nuclear translocation of NF-κB was determined by electrophoretic mobility shift assay and immunofluorescence staining. Cell adhesion was assayed by measuring the binding of fluorescence labelled MOLT-4 cells.Results—TNF-α induced ICAM-1 mRNA and protein expression in IEC-6 cells, which was followed by increased adhesion of MOLT-4 lymphocytes. Blocking TNF-α induced IκBα degradation with proteasome inhibitors reduced TNF-α induced NF-κB activation and ICAM-1 gene induction and notably decreased MOLT-4 cell adhesion without affecting Jun N-terminal kinase (JNK/SAPK) activity or de novo protein synthesis.Conclusion—TNF-α induction of ICAM-1 expression is mediated by the transcription factor NF-κB and can be inhibited by blocking IκBα degradation. Thus the IκB/NF-κB system is a promising target for pharmacological modulation of the expression of adhesion molecules and other inflammatory genes in the intestine.


2008 ◽  
Vol 76 (10) ◽  
pp. 4737-4744 ◽  
Author(s):  
Jeffrey Fischer ◽  
Colby Suire ◽  
Hollie Hale-Donze

ABSTRACT Microsporidia are obligate intracellular parasites that are ubiquitous in nature and have been recognized as causing an important emerging disease among immunocompromised individuals. Limited knowledge exists about the immune response against these organisms, and virtually nothing is known about the receptors involved in host recognition. Toll-like receptors (TLR) are pattern recognition receptors that bind to specific molecules found on pathogens and signal a variety of inflammatory responses. In this study, we show that both Encephalitozoon cuniculi and Encephalitozoon intestinalis are preferentially recognized by TLR2 and not by TLR4 in primary human macrophages. This is the first demonstration of host receptor recognition of any microsporidian species. TLR2 ligation is known to activate NF-κB, resulting in inflammatory cytokines, such as tumor necrosis factor alpha (TNF-α) and interleukin-8 (IL-8). We found that the infection of primary human macrophages leads to the nuclear translocation of NF-κB in as early as 1 h and the subsequent production of TNF-α and IL-8. To verify the direct role of TLR2 parasite recognition in the production of these cytokines, the receptor was knocked down in primary human macrophages using small interfering RNA. This knockdown resulted in decreases in both the nuclear translocation of NF-κB and the levels of TNF-α and IL-8 after challenge with spores. Taken together, these experiments directly link the initial inflammatory response induced by Encephalitozoon spp. to TLR2 stimulation in human macrophages.


2005 ◽  
Vol 73 (5) ◽  
pp. 2766-2777 ◽  
Author(s):  
Jing Wang ◽  
Francis Gigliotti ◽  
Sanjay Maggirwar ◽  
Carl Johnston ◽  
Jacob N. Finkelstein ◽  
...  

ABSTRACT Pneumocystis carinii pneumonia (PcP) is a clinically important infection of immunocompromised patients. Although the interaction of Pneumocystis with the alveolar epithelium has been well documented, very little information regarding the epithelial response to Pneumocystis is currently available. In order to study Pneumocystis-epithelium interactions, a murine cell line derived specifically from an alveolar epithelial cell (AEC) was utilized. The coculture of murine AECs with mouse Pneumocystis induced a dose- and time-dependent release of the CXC chemokine MIP-2. Importantly, the specific removal of Pneumocystis from the preparation, or the pretreatment of AECs with sulfasalazine, a potent and specific inhibitor of NF-κB, nearly completely abrogated the chemokine response to Pneumocystis. Since the murine MIP-2 promoter contains consensus κB binding sequences, the ability of Pneumocystis to stimulate NF-κB signaling in AECs was examined. Pneumocystis stimulation of an AEC line stably transfected with a κB-dependent reporter construct triggered the NF-κB signaling pathway and reporter production. These data were confirmed in gel shift assays, providing direct evidence that Pneumocystis induced the nuclear translocation of the p50/p65 heterodimeric form of NF-κB. Maximal NF-κB activation was dependent upon direct contact with viable Pneumocystis organisms. These data demonstrate that Pneumocystis activates NF-κB signaling in AECs and establish a reporter cell line for studying NF-κB activation in AECs. Given the global regulatory functions of the NF-κB family, these findings suggest that Pneumocystis directly alters AEC gene expression in a manner that promotes pulmonary immune and inflammatory responses.


2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Hongming Lv ◽  
Hua Ren ◽  
Lidong Wang ◽  
Wei Chen ◽  
Xinxin Ci

Licochalcone A (Lico A) exhibits various biological properties, including anti-inflammatory and antioxidant activities. In this study, we investigated the antioxidative potential and mechanisms of Lico A againsttert-butyl hydroperoxide- (t-BHP-) induced oxidative damage in RAW 264.7 cells. Our results indicated that Lico A significantly inhibitedt-BHP-induced cytotoxicity, apoptosis, and reactive oxygen species (ROS) generation and reduced glutathione (GSH) depletion but increased the glutamate-cysteine ligase modifier (GCLM) subunit and the glutamate-cysteine ligase catalytic (GCLC) subunit genes expression. Additionally, Lico A dramatically upregulated the antioxidant enzyme heme oxygenase 1 (HO-1) and nuclear factor erythroid 2-related factor 2 (Nrf2), which were associated with inducing Nrf2 nuclear translocation, decreasing Keap1 protein expression and increasing antioxidant response element (ARE) promoter activity. Lico A also obviously induced the activation of serine/threonine kinase (Akt) and extracellular signal-regulated kinase (ERK), but PI3K/Akt and ERK inhibitors treatment displayed clearly decreased levels of LicoA-induced Nrf2 nuclear translocation and HO-1 expression, respectively. Furthermore, Lico A treatment markedly attenuatedt-BHP-induced oxidative damage, which was reduced by treatment with PI3K/Akt, ERK, and HO-1 inhibitors. Therefore, Lico A might have a protective role againstt-BHP-induced cytotoxicity by modulating HO-1 and by scavenging ROS via the activation of the PI3K/Akt and ERK/Nrf2 signaling pathways.


2011 ◽  
Vol 301 (3) ◽  
pp. H712-H720 ◽  
Author(s):  
Hao Wei ◽  
Balz Frei ◽  
Joseph S. Beckman ◽  
Wei-Jian Zhang

Redox-active transition metal ions, such as iron and copper, may play an important role in vascular inflammation, which is an etiologic factor in atherosclerotic vascular diseases. In this study, we investigated whether tetrathiomolybdate (TTM), a highly specific copper chelator, can act as an anti-inflammatory agent, preventing lipopolysaccharide (LPS)-induced inflammatory responses in vivo. Female C57BL/6N mice were daily gavaged with TTM (30 mg/kg body wt) or vehicle control. After 3 wk, animals were injected intraperitoneally with 50 μg LPS or saline buffer and killed 3 h later. Treatment with TTM reduced serum ceruloplasmin activity by 43%, a surrogate marker of bioavailable copper, in the absence of detectable hepatotoxicity. The concentrations of both copper and molybdenum increased in various tissues, whereas the copper-to-molybdenum ratio decreased, consistent with reduced copper bioavailability. TTM treatment did not have a significant effect on superoxide dismutase activity in heart and liver. Furthermore, TTM significantly inhibited LPS-induced inflammatory gene transcription in aorta and heart, including vascular and intercellular adhesion molecule-1 (VCAM-1 and ICAM-1, respectively), monocyte chemotactic protein-1 (MCP-1), interleukin-6, and tumor necrosis factor (TNF)-α (ANOVA, P < 0.05); consistently, protein levels of VCAM-1, ICAM-1, and MCP-1 in heart were also significantly lower in TTM-treated animals. Similar inhibitory effects of TTM were observed on activation of nuclear factor-κB (NF-κB) and activator protein-1 (AP-1) in heart and lungs. Finally, TTM significantly inhibited LPS-induced increases of serum levels of soluble ICAM-1, MCP-1, and TNF-α (ANOVA, P < 0.05). These data indicate that copper chelation with TTM inhibits LPS-induced inflammatory responses in aorta and other tissues of mice, most likely by inhibiting activation of the redox-sensitive transcription factors, NF-κB and AP-1. Therefore, copper appears to play an important role in vascular inflammation, and TTM may have value as an anti-inflammatory or anti-atherogenic agent.


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