Nuclear factor-κB Transcriptional Activity Research Articles

Involvement of heme oxygenase-1 induction in anti-vascular inflammation effects of Xanthoceras sorbifolia in human umbilical vein endothelial cells

OBJECTIVETo define the effects of Xanthoceras sorbifolia (EXS) on vascular inflammation and the mechanisms in endothelial cells. METHODSVascular protective effects of an ethanol extract of seeds from EXS (1-50 μg/mL) against tumor necrosis factor-α (TNF-α)-induced vascular inflammation were examined in human umbilical vein endothelial cells (HUVECs). RESULTSEXS significantly decreased TNF-α-induced expression of cell adhesion molecules, such as intracellular adhesion molecule-1, vascular cell adhesion molecule-1, and endothelial cell selectin, in a dose-dependent manner. Pre-treatment with EXS significantly inhibited translocation and transcriptional activity of nuclear factor-κB (NF-κB) increased by TNF-α. EXS also significantly inhibited formation of intracellular reactive oxygen species (ROS). Moreover, the vascular protective effects of EXS were linked to up-regulation of heme oxygenase-1 (HO-1) and nuclear factor E2-related factor-2 (Nrf-2) expression. EXS-induced HO-1 expression was significantly decreased in SnPP (HO-1 inhibitor)- and HO-1 siRNA-treated cells, whereas an increase was found in cobalt protoporphyrin IX (CoPP) (HO-1 inducer)-treated cells. In addition, pretreatment with EXS increased HO-1 and Nrf-2 expression under TNF-α stimulation with or without N-acetyl-L-cysteine. Furthermore, the inhibitory effects of EXS on TNF-α-induced vascular inflammation were partially reversed in SnPP- and of HO-1 siRNA-treated cells but increased by CoPP. CONCLUSIONThese results suggest that EXS may have important implications for prevention of vascular complications associated with vascular inflammation by inhibition of the NF-κB/ROS pathway and activation of the Nrf-2/HO-1 pathway.

DDIT3 regulates cementoblast mineralization by isocitrate dehydrogenase 1 through nuclear factor-κB pathway.

DDIT3 is of great importance in endoplasmic reticulum stress and is involved in many inflammatory diseases and mineralization processes. The cementum protects teeth from periodontitis and provides attachment for Sharpey's fibers of the periodontal ligament. However, the effect of DDIT3 on cementoblast differentiation remains largely unknown. In this study, we found that DDIT3 was suppressed during cementoblast differentiation. Knockdown of DDIT3 increased the messenger RNA(mRNA) and protein levels of several key osteogenic markers in vitro, including alkaline phosphatase, runt-related transcription factor 2, and osteocalcin (OCN). In addition, isocitrate dehydrogenase 1 (IDH1) was increased during cementoblast differentiation, and knockdown of DDIT3 increased the protein and mRNA levels of IDH1. Furthermore, inhibition of IDH1 could partially reduce the effect of DDIT3 on cementoblast differentiation. The DDIT3 knockdown activated nuclear factor-κB (NF-κB) transcriptional activity and upregulated the expression of p-p65 and p-IκBα. The increased osteogenic differentiation ability and IDH1 expression, as induced by the DDIT3 knockdown, could be partially turned over by the addition of NF-κB inhibitor BAY 11-7082. Overall, our data clarified that DDIT3 suppresses cementoblast differentiation through IDH1, via the NF-κB pathway.

Mesenchymal stem cells overexpressing heme oxygenase-1 ameliorate lipopolysaccharide-induced acute lung injury in rats.

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are common and potentially lethal clinical syndromes characterized by acute respiratory failure resulting from excessive pulmonary inflammation, noncardiogenic pulmonary edema, and alveolar-capillary barrier disruption. At present, there is no effective and specific therapy for ALI/ARDS. Mesenchymal stem cells (MSCs) have well-known therapeutic potential in patients with ALI/ARDS. Heme oxygenase-1 (HO-1), a cytoprotective enzyme, possesses antioxidative, anti-inflammatory, and antiapoptotic effects. Thus, a combination of MSC transplantation with HO-1 delivery may have an additional protective effect against ALI/ARDS. This study investigated the effect of HO-1-modified bone-marrow-derived MSCs (MSCs-HO-1) on lipopolysaccharide (LPS)-induced ALI and its underlying mechanisms. We established MSCs-HO-1 through lentiviral transduction. The ALI rat model was established by successive LPS inhalations following injection with MSCs-HO-1. The survival rate, histological changes in the lungs, total protein concentration and neutrophil counts in bronchoalveolar lavage fluid, lung wet/dry weight ratio, cytokine levels in serum and lungs, nuclear transcription factor-κB activity, and protein expression of Toll-like receptor 4 signaling adaptors were examined. Furthermore, the cell viability, apoptosis, and paracrine activity of MSCs-HO-1 were examined under inflammatory stimuli in vitro. MSCs-HO-1 injection improved these parameters compared with primary unmodified MSCs. Moreover, MSCs-HO-1 had superior prosurvival and antiapoptotic properties and enhanced paracrine functions in vitro. Therefore, MSCs-HO-1 exert an enhanced protective effect to alleviate LPS-induced ALI in rats, and the mechanisms may be partially associated with superior prosurvival, antiapoptosis, and enhanced paracrine functions of MSCs-HO-1. These findings provide a novel insight into MSC-based therapeutic strategies for treating ALI/ARDS.

Role of RKIP in human hepatic stellate cell proliferation, invasion, and metastasis.

The purpose of this study was to investigate the effect of Raf kinase inhibitor protein (RKIP) on the growth, apoptosis, invasion, and metastasis of human hepatic stellate cell line (LX-2). A recombinant plasmid (pcDNA3.1-RKIP) or RKIP-targeting small interfering RNA (siRNA) vector (siRNA-RKIP) was transfected into LX-2 cells to interfere with the RKIP expression. The results demonstrated that increased RKIP expression significantly reduced cell viability, clonogenic growth, and invasion. Further, it promoted cell apoptosis and induced cell cycle arrest in the G1 phase. Overexpression of RKIP led to inactivation of LX-2 cells, as evidenced by the decrease in the expression levels of collagen I and α-smooth muscle actin (α-SMA). In addition, increased RKIP expression significantly reduced the phosphorylation of Raf/extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK), the transcriptional activity of nuclear factor-κB (NF-κB), and the levels of matrix metalloproteinases-1 and -2. In conclusion, these findings clearly demonstrate that RKIP inhibits LX-2 cell growth, metastasis, and activation, primarily by downregulating the ERK/MAPK and NF-κB signaling pathways.

Anti-inflammatory activity of mulberrofuran K isolated from the bark of Morus bombycis

Morus bombycis Koidzumi, commonly known as silkworm mulberry, is a plant belonging to family Moraceae. It has been used in Asian countries as a traditional medicine for treating hypertension, diabetes, and inflammatory disorders. In this study, we isolated eleven compounds from the cortex of M. bombycis and evaluated their inhibitory effects on nitric oxide (NO) production as an indicator of their anti-inflammatory activities using lipopolysaccharide (LPS)-stimulated murine macrophages. Compound 4 showed the most potent inhibitory activity on NO production. It was identified as mulberrofuran K (MFK). Anti-inflammatory activity of MFK was then carried out using LPS-stimulated RAW264.7 cells. MFK suppressed the production of NO, reactive oxygen species (ROS), and proinflammatory cytokines (interleukin (IL)-1β, IL-6 and tumor necrosis factor alpha (TNF-α)) in a concentration-dependent manner. Western blot analysis revealed that MFK treatment inhibited expression levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). MFK also inhibited transcriptional activation of nuclear factor-κB (NF-κB) and extracellular-regulated kinases (ERK) 1/2 in LPS-stimulated murine macrophages. These results suggest that MFK, an anti-inflammatory constituents of M. bombycis cortex, has potential as a therapeutic candidates for preventing and treating inflammatory diseases.

Mesenchymal Stem Cells Modified with Heme Oxygenase-1 Have Enhanced Paracrine Function and Attenuate Lipopolysaccharide-Induced Inflammatory and Oxidative Damage in Pulmonary Microvascular Endothelial Cells

Background/Aims: Bone marrow-derived mesenchymal stem cell (BM-MSC) transplantation has therapeutic effects on endothelial damage during acute lung injury (ALI). Heme oxygenase-1 (HO-1) can restore homeostasis and implement cytoprotective defense functions in many pathologic states. Therefore, we explored whether transduction of HO-1 into BM-MSCs (MSCs-HO-1) would have an increased beneficial effect on lipopolysaccharide (LPS)-induced inflammatory and oxidative damage in human pulmonary microvascular endothelial cells (PVECs). Methods: MSCs were isolated from rat bone marrow and transfected with the HO-1 gene by a lentivirus vector. The phenotype and multilineage differentiation of MSCs were assessed. MSCs or MSCs-HO-1 were co-cultured with PVECs using a transwell system, and LPS was added to induce PVEC injury. The production of reactive oxygen species (ROS), and the activities of lipid peroxide (LPO), malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GPx) in PVECs were determined by flow cytometry and colorimetric assays, respectively. The levels of human PVEC-derived tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6 in the supernatants of the co-culture system, and the activity of nuclear transcription factor-κB and NF-E2-related factor 2 (Nrf2) in PVECs were examined by enzyme-linked immunosorbent assay (ELISA). The mRNA expression of TNF-α, IL-1β and IL-6 in PVECs was detected by quantitative real-time polymerase chain reaction (qRT-PCR), HO-1 expression and enzymatic activity in PVECs and the influence of zinc protoporphyrin (ZnPP) or HO-1 small interfering RNA on the above inflammatory and oxidative stress markers were evaluated. In addition, the expression of rat MSC-derived hepatocyte growth factor (HGF) and IL-10 was determined by ELISA and qRT-PCR. Results: MSCs showed no significant changes in phenotype or multilineage differentiation after transduction. LPS strongly increased the production of inflammatory and oxidative stress indicators, as well as decreased the levels of antioxidant components and the activity of Nrf2 in PVECs. MSC co-cultivation ameliorated these detrimental effects in PVECs and MSCs-HO-1 further improved the damage to PVECs induced by LPS when compared with MSCs alone. The beneficial effects of MSCs-HO-1 were dependent on HO-1 overexpression and may be attributed to the enhanced paracrine production of HGF and IL-10. Conclusion: MSCs-HO-1 have an enhanced ability to improve LPS-induced inflammatory and oxidative damage in PVECs, and the mechanism may be partially associated with the enhanced paracrine function of the stem cells. These data encourage further testing of the beneficial effects of MSCs-HO-1 in ALI animal models.

The IL-1β signalling pathway and its role in regulating pro-inflammatory and pro-labour mediators in human primary myometrial cells

Interleukin (IL)-1β plays a central role in the processes of human labour and delivery. The adaptor proteins involved in the IL-1β signalling pathway in human myometrium are not known. This study sought to determine the role of the adaptor proteins myeloid differentiation primary response 88 (MyD88), tumour necrosis factor receptor-associated factor 6 (TRAF6), IL-1 receptor-associated kinase 4 (IRAK4) and transforming growth factor beta-activated kinase 1 (TAK1) in IL-1β-induced formation of pro-inflammatory and pro-labour mediators in human myometrium. Human primary myometrial cells were transfected with siRNA against MyD88 (siMYD88), TRAF6 (siTRAF6), IRAK4 (siIRAK4) or TAK1 (siTAK1), treated with IL-1β, and assayed for the mRNA expression and or secretion of pro-inflammatory and pro-labour mediators. Transfection of primary myometrial cells with siMYD88, siTRAF6, siIRAK4 and siTAK1 significantly decreased IL-1β-induced IL-1α, IL-6, growth-regulated alpha protein (GRO-α), IL-8, monocyte chemoattractant protein (MCP)-1, intercellular adhesion molecule (ICAM)-1 and cyclooxygenase (COX)-2 mRNA expression and release of IL-6, GRO-α, IL-8, MCP-1, ICAM-1 and prostaglandin PGF2α. The expression and secretion of the extracellular matrix remodelling enzyme matrix metalloproteinase (MMP)-9 was significantly lower with siMYD88 and siTRAF6. Finally, IL-1β-induced nuclear factor κB (NF-κB) transcriptional activity was significantly attenuated by transfection with siMyD88, siTRAF6 and siIRAK4; there was no effect of siTAK1 transfection on NF-κB transcriptional activity. Collectively, these findings suggest that MyD88, TRAF6, IRAK4 and TAK1 are involved in IL-1β signalling in human myometrium. Further studies are required to determine if inhibition of these proteins can prevent preterm birth.

RETRACTED: LncRNA HOTAIR alleviates rheumatoid arthritis by targeting miR-138 and inactivating NF-κB pathway

Rheumatoid arthritis (RA) is a chronic and autoimmune-mediated inflammatory disease. We aimed to investigate the regulation of lncRNA HOTAIR in LPS-treated chondrocytes and RA mouse. Our results showed that HOTAIR expression was significantly reduced in LPS-treated chondrocytes. The HOTAIR was then over-expressed in chondrocytes by transfecting recombinant lentivirus carrying sequences encoding HOTAIR. The LPS-induced reduction of cell proliferation rate and production of two inflammatory factors interleukin (IL)-17, IL-23 were markedly inhibited. Enforced expression of HOTAIR also led to the upregulation of proliferation-related protein Ki67 and proliferating cell nuclear antigen (PCNA). Moreover, a negative correlation was detected between the expression of HOTAIR and microRNA (miR)-138, and the expression of miR-138 was significantly increased in LPS-induced chondrocytes. The effects of HOTAIR over-expression on the proliferation and inflammation were partly reversed by miR-138 overexpression. Furthermore, the overexpression of HOTAIR significantly inhibited the activation of nuclear transcription factor-κB (NF-κB) in LPS-treated chondrocytes by suppressing p65 to cell nucleus, resulting in the down-regulation of IL-1β and tumor necrosis factor (TNF)-α. In addition, the in vivo experiments exhibited that overexpression of HOTAIR increased cell proliferation and inhibited inflammation in RA rats, which were demonstrated by upregulation of Ki67 and PCNA, reduced CD4+IL-17+,CD4+IL-23+ cells, and down-regulation of p-p65, IL-1β and TNF-α. In summary, our study suggests HOTAIR plays a protective role in RA by increasing proliferation rate and inhibiting inflammation, which may be related with the regulation of miR-138 expression and NF-κB signaling pathway. These results suggest that the regulation of HOTAIR may be a promising therapeutic strategy for RA.

TCL1A Single-Nucleotide Polymorphisms and Estrogen-Mediated Toll-Like Receptor-MYD88-Dependent Nuclear Factor-κB Activation: Single-Nucleotide Polymorphism- and Selective Estrogen Receptor Modulator-Dependent Modification of Inflammation and Immune Response.

In a previous genome-wide association study (GWAS) for musculoskeletal adverse events during aromatase inhibitor therapy for breast cancer, we reported that single nucleotide polymorphisms (SNPs) near the TCL1A gene were associated with this adverse drug reaction. Functional genomic studies showed that TCL1A expression was induced by estradiol, but only in cells with the variant sequence for the top GWAS SNP (rs11849538), a SNP that created a functional estrogen response element. In addition, TCL1A genotype influenced the downstream expression of a series of cytokines and chemokines and had a striking effect on nuclear factor κB (NF-κB) transcriptional activity. Furthermore, this SNP-dependent regulation could be reversed by selective ER modulators (SERMs). The present study was designed to pursue mechanisms underlying TCL1A SNP-mediated, estrogen-dependent NF-κB activation. Functional genomic studies were performed using a panel of 300 lymphoblastoid cell lines for which we had generated genome-wide SNP and gene expression data. It is known that toll-like receptors (TLRs) can regulate NF-κB signaling by a process that requires the adaptor protein MYD88. We found that TLR2, TLR7, TLR9, and TLR10 expression, as well as that of MYD88, could be modulated by TCL1A in a SNP and estrogen-dependent fashion and that these effects were reversed in the presence of SERMs. Furthermore, MYD88 inhibition blocked the TCL1A SNP and estrogen-dependent NF-κB activation, as well as protein-protein interaction between TCL1A and MYD88. These observations greatly expand the range of pathways influenced by TCL1A genotype and raise the possibility that this estrogen- and SNP-dependent regulation might be altered pharmacologically by SERMs.

Repressor activator protein 1-promoted colorectal cell migration is associated with the regulation of Vimentin.

Repressor activator protein 1 plays important roles in telomere protection, while repressor activator protein 1 binds to extra-telomeric DNA and exerts the function as a transcriptional regulator. Previous study showed that repressor activator protein 1 regulates the transcriptional activity of nuclear factor-κB, and it was highly expressed in breast cancer tissues; however, the clinical significance of repressor activator protein 1 expression in cancer remains to be elucidated. In this study, we discovered that repressor activator protein 1 was highly expressed in colorectal cancer tissues. High expression of repressor activator protein 1 was significantly correlated with poor prognosis and distant metastasis. Knockdown of repressor activator protein 1 in colorectal cancer cells did not affect cell proliferation or colony formation, but dramatically decreased cell migration and F-actin-enriched membrane protrusions. Microarray screening revealed that Vimentin was downregulated after repressor activator protein 1 knockdown, which was validated by analysis of a colorectal cancer dataset. Furthermore, knockdown of Vimentin attenuated repressor activator protein 1-enhanced cell migration. Thus, our study suggests that repressor activator protein 1 is a prognostic marker and a potential target for colorectal cancer therapy.

TRADD, TRAF2, RIP1 and TAK1 are required for TNF-α-induced pro-labour mediators in human primary myometrial cells.

TNF-α plays a central role in the processes of human labour and delivery. This study sought to determine the role of the adaptor proteins TNFR1-associated death domain protein (TRADD), TNF receptor-associated factor 2 (TRAF2), receptor interacting protein 1 (RIP1) and transforming growth factor beta-activated kinase 1 (TAK1) in TNF-α-induced formation of pro-labour mediators. Human primary myometrial cells were transfected with siRNA against TRADD (siTRADD), TRAF2 (siTRAF2), RIP1 (siRIP1) or TAK1 (siTAK1), treated with TNF-α, and assayed for pro-inflammatory mediators expression. siTRADD, siTRAF2, siRIP1 and siTAK1 significantly decreased TNF-α-induced IL-1α, IL-1β, IL-6, IL-8, MCP-1 mRNA expression and release of IL-6, IL-8 and MCP-1; and cyclooxygenase (COX)-2 expression and release of prostaglandin PGF2α . There was a significant attenuation of TNF-α-induced expression of adhesion molecules ICAM-1 and VCAM-1 mRNA with siTRADD, siTRAF2 or siRIP1. siTRADD and siRIP1 significantly attenuated TNF-α-induced MMP-9 mRNA expression and release and nuclear factor κB (NF-κB) transcriptional activity. There was a significant increase in TNF-α-induced sVCAM-1 release, MMP-9 mRNA expression and NF-κB activity with siTAK1. TRADD, TRAF2, RIP1 and TAK1 are involved in TNF-α signalling in human myometrium. Further studies are required to determine whether inhibition of these proteins can prevent preterm birth.

Chemopreventive effects of a low-side-effect antibiotic drug, erythromycin, on mouse intestinal tumors.

It is important to establish effective methods for preventing colorectal cancer because the number of colorectal cancer deaths is increasing. Erythromycin one of the macrolide antibiotics, has been shown to exert pleiotropic effects, such as anti-inflammatory and anti-oxidative effects, on mammalian cells. In the present study, we aimed to evaluate the preventive effects of erythromycin on intestinal carcinogenesis. We first confirmed that erythromycin suppresses the transcriptional activity of nuclear factor-κB and activator protein-1 and the expression of its downstream targets, interleukin-6 and cyclooxygenase-2 in human colon cancer cells. Next, we fed 5-week-old male Apc mutant Min mice with diets containing 500 ppm erythromycin for 15 weeks. Erythromycin treatment significantly reduced the number of proximal intestinal polyps to 70.9% of the untreated control value. Moreover, erythromycin reduced the levels of interleukin-6 and cyclooxygenase-2 mRNA expression in intestinal polyps. Although the levels of hepatic NADPH oxidase mRNA were decreased, erythromycin treatment did not affect the levels of oxidative stress markers, reactive carbonyl species, in the liver of Min mice. Our results suggest that erythromycin suppresses intestinal polyp development in Min mice, in part by attenuating local inflammation, and indicate that erythromycin is useful as a chemopreventive agent.

Therapeutic Potential of Medicinal Plants and Their Constituents on Lung Inflammatory Disorders.

Acute bronchitis and chronic obstructive pulmonary diseases (COPD) are essentially lung inflammatory disorders. Various plant extracts and their constituents showed therapeutic effects on several animal models of lung inflammation. These include coumarins, flavonoids, phenolics, iridoids, monoterpenes, diterpenes and triterpenoids. Some of them exerted inhibitory action mainly by inhibiting the mitogen-activated protein kinase pathway and nuclear transcription factor-κB activation. Especially, many flavonoid derivatives distinctly showed effectiveness on lung inflammation. In this review, the experimental data for plant extracts and their constituents showing therapeutic effectiveness on animal models of lung inflammation are summarized.

Quercetin and baicalein suppress monocrotaline-induced hepatic sinusoidal obstruction syndrome in rats

Hepatic sinusoidal obstruction syndrome (SOS) is a rare liver disease with considerable mortality. This study is designed to observe the protection of quercetin and baicalein against monocrotaline (MCT)-induced SOS in rats and its engaged mechanism. Rats were pre-administrated with MCT (90mg/kg) to induce SOS, and 6, 30h later were orally given with quercetin and baicalein (40mg/kg) twice. Results of detecting rats with liver ascites, measuring serum transaminases, total bilirubin (TBil) and bile acids (TBA), analyzing blood cells, liver histological evaluation and scanning electron microscope observation all demonstrated the detoxification of quercetin and baicalein against MCT-induced SOS in rats. Quercetin and baicalein reduced the increased metalloproteinase-9 (MMP-9) expression, liver myeloperoxidase (MPO) activity, toll-like receptor (TLR)-2,3,6,9 expression and nuclear factor κB (NFκB) transcriptional activation induced by MCT. Quercetin and baicalein reduced MCT-induced nuclear translocation of early growth response1 (Egr1) and increased expression of Serpine1 and tissue factor (TF). Quercetin and baicalein reduced MCT-induced increased liver malondialdehyde (MDA) amount and enhanced the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2). Quercetin and baicalein also abrogated MCT-induced activation of mitogen-activated protein kinases (MAPKs) and phosphatidylinositol 3-kinase (PI3K) signaling cascades. In conclusion, this study demonstrated the protection of quercetin and baicalein against MCT-induced SOS in rats, indicating the potential application of them for the treatment of SOS in clinic. Transcriptional factor NFκB, Egr1 and Nrf2-regulated inflammation, coagulation-fibrinolysis and antioxidant, and PI3K and MAPKs signaling cascades are all involved such protection.

The anti-inflammatory role of extranuclear apurinic/apyrimidinic endonuclease 1/redox effector factor-1 in reactive astrocytes.

Apurinic/apyrimidinic endonuclease 1 (APE1), a ubiquitous multipurpose protein, is also known as redox effector factor-1 (Ref-1). It is involved in DNA repair and redox signaling and, in turn, oxidative stress-induced neurodegeneration. Although previous studies have demonstrated that APE1/Ref-1 functions as a negative regulator of inflammatory response via several mechanisms in neuronal cells, little is known about the roles of APE1/Ref-1 in glial cells. In this study, we found that cytoplasmic APE1/Ref-1 expression was upregulated in reactive astrocytes of the kainic acid- or lipopolysaccharide (LPS)-injected hippocampus. Analysis of the inflammatory response induced by extranuclear APE1/Ref-1 (ΔNLS-Ref-1) in cultured primary astrocytes revealed that it markedly suppressed inducible nitric oxide synthase (iNOS) expression and tumor necrosis factor-α (TNF-α) secretion induced by LPS to a similar extent as did wild type APE1/Ref-1 (WT-Ref-1), supporting the concept an anti-inflammatory role of extranuclear APE1/Ref-1 in astrocytes. Additionally, overexpression of WT- and ΔNLS-Ref-1 suppressed the transcriptional activity of nuclear factor-κB (NF-κB), although it effectively enhanced activator protein 1 (AP-1) activity. The blunting effect of APE1/Ref-1 on LPS-induced NF-κB activation was not mediated by IκB kinase (IKK) activity. Instead, APE1/Ref-1 inhibited p300-mediated acetylation of p65 by suppressing intracellular reactive oxygen species (ROS) levels following LPS treatment. Taken together, our results showed that altered expression and/or subcellular distribution of APE1/Ref-1 in activated astrocytes regulated the neuroinflammatory response to excitotoxin and endotoxin insults used in model of neurodegenerative brain diseases.

Inhibition of the nuclear export of p65 and IQCG in leukemogenesis by NUP98-IQCG.

NUP98 fuses with approximately 34 different partner genes via translocation in hematological malignancies. Transgenic or retrovirus-mediated bone marrow transplanted mouse models reveal the leukemogenesis of some NUP98-related fusion genes. We previously reported the fusion protein NUP98-IQ motif containing G (IQCG) in a myeloid/T lymphoid bi-phenoleukemia patient with t(3;11) and confirmed its leukemogenic ability. Herein, we demonstrated the association of NUP98-IQCG with CRM1, and found that NUP98-IQCG expression inhibits the CRM1-mediated nuclear export of p65 and enhances the transcriptional activity of nuclear factor-κB. Moreover, IQCG could be entrapped in the nucleus by NUP98-IQCG, and the fusion protein interacts with calmodulin via the IQ motif in a calcium-independent manner. Therefore, the inhibition of nuclear exports of p65 and IQCG might contribute to the leukemogenesis of NUP98-IQCG.

Fluctuations in glucose levels induce glial toxicity with glutamatergic, oxidative and inflammatory implications

Astrocytes are dynamic cells that maintain brain homeostasis by regulating neurotransmitter systems, antioxidant defenses, inflammatory responses and energy metabolism. Astroglial cells are also primarily responsible for the uptake and metabolism of glucose in the brain. Diabetes mellitus (DM) is a pathological condition characterized by hyperglycemia and is associated with several changes in the central nervous system (CNS), including alterations in glial function. Classically, excessive glucose concentrations are used to induce experimental models of astrocyte dysfunction; however, hypoglycemic episodes may also cause several brain injuries. The main focus of the present study was to evaluate how fluctuations in glucose levels induce cytotoxicity. The culture medium of astroglial cells was replaced twice as follows: (1) from 6mM (control) to 12mM (high glucose), and (2) from 12mM to 0mM (glucose deprivation). Cell viability, mitochondrial function, oxidative/nitrosative stress, glutamate metabolism, inflammatory responses, nuclear factor κB (NFκB) transcriptional activity and p38 mitogen-activated protein kinase (p38 MAPK) levels were assessed. Our in vitro experimental model showed that up and down fluctuations in glucose levels decreased cell proliferation, induced mitochondrial dysfunction, increased oxidative/nitrosative stress with consequent cellular biomolecular damage, impaired glutamate metabolism and increased pro-inflammatory cytokine release. Additionally, activation of the NFκB and p38 signaling pathways were putative mechanisms of the effects of glucose fluctuations on astroglial cells. In summary, for the first time, we show that changes in glucose concentrations, from high-glucose levels to glucose deprivation, exacerbate glial injury.

Anti-inflammatory action of the ethanolic extract from Sargassum serratifolium on lipopolysaccharide-stimulated mouse peritoneal macrophages and identification of active components

Sargassum, a genus of brown algae (Phaeophyceae) in the Sargassaceae family, comprises approximately 400 species in the world. Among them, Sargassum serratifolium has been reported to have high level of meroterpenoids, which have antioxidant, anti-inflammatory, and neuroprotective activities. This study investigated the anti-inflammatory mechanism of ethanolic extract of S. serratifolium (ESS) in lipopolysaccharide (LPS)-stimulated peritoneal macrophages and identified anti-inflammatory compounds in ESS. ESS inhibited LPS-induced nitric oxide (NO) and prostaglandin E2 and the expression of inducible nitric oxide synthase and cyclooxygenase-2. ESS also reduced the release of pro-inflammatory cytokines in a dose-dependent manner. LPS-induced nuclear factor-κB transcriptional activity and translocation into the nucleus were significantly inhibited by ESS treatment through the prevention of the degradation of inhibitor κB-α. Furthermore, ESS inhibited the production of pro-inflammatory cytokines in mouse serum. The main anti-inflammatory components in ESS were identified as sargahydroquinoic acid, sargachromenol, and sargaquinoic acid based on the inhibition of NO production. Our results indicate that ESS can be used as a potential source of therapeutic agents for the treatment of inflammatory diseases.

Cnidilide, an alkylphthalide isolated from the roots of Cnidium officinale, suppresses LPS-induced NO, PGE2, IL-1β, IL-6 and TNF-α production by AP-1 and NF-κB inactivation in RAW 264.7 macrophages

Cnidilide, an alkyl phthalide isolated from the rhizome of Cnidium officinale, has been reported to possess antispasmodic and sedative effects. However, the anti-inflammatory capacity and molecular mechanism of cnidilide have not been studied to date. In the present study, we investigated the inhibitory effects of cnidilide on LPS-induced pro-inflammatory mediators and the underlying molecular mechanisms in RAW 264.7 macrophages. Our results indicated that cnidilide potently inhibits inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression at the protein and mRNA levels and their promoter activities, causing attendant decreases in the production of nitric oxide (NO) and prostaglandin E2 (PGE2). In addition, cnidilide reduced LPS-induced production and mRNA expression of interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α) in a dose-dependent manner. Molecular data revealed that cnidilide inhibited LPS-induced transcriptional activity of activator protein-1 (AP-1) by reducing the phosphorylation and nuclear translocation of c-Fos and c-Jun. In addition, cnidilide attenuated LPS-induced transcriptional activity of nuclear factor-κB (NF-κB), and this reduction was accompanied by parallel reduction in the phosphorylation, but not in the translocation of p65 NF-κB. In addition, cnidilide inhibited LPS-induced phosphorylation of p38 mitogen-activated protein kinase (MAPK) and mitogen- and stress-activated protein kinase 1(MSK-1), a downstream kinase. Moreover, the phosphorylation of c-Jun N-terminal kinase (JNK) was suppressed by cnidilide in a concentration-dependent manner, whereas it did not inhibit the extracellular signal-regulated kinase (ERK) phosphorylation in LPS-stimulated RAW 264.7 macrophages. Taken together, our findings suggest that cnidilide has anti-inflammatory properties by inhibiting p38 MAPK, JNK, AP-1, and the NF-κB pathway in LPS-stimulated RAW 264.7 macrophages.

Chlorogenic acid suppresses monocrotaline-induced sinusoidal obstruction syndrome: The potential contribution of NFκB, Egr1, Nrf2, MAPKs and PI3K signals.

Hepatic sinusoidal obstruction syndrome (SOS) is a highly lethal liver disease. This study aims to observe the protection and its engaged mechanism of chlorogenic acid (CGA) against monocrotaline (MCT)-induced SOS. Results of detecting liver ascites, measuring serum transaminases, liver histological evaluation and scanning electron microscope observation all demonstrated that CGA prevented MCT-induced SOS in rats. CGA reduced MCT-induced increased liver myeloperoxidase (MPO) activity, tumor necrosis factor (TNF)α and interleukin (IL)-1β mRNA expression, toll-like receptor (TLR)-2,3,6,9 expression, and nuclear factor κB (NFκB) transcriptional activation. CGA also decreased MCT-induced early growth response1 (Egr1) activation. CGA reduced MCT-induced elevated liver malondialdehyde (MDA) amount and enhanced nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2). CGA blocked MCT-induced PI3K and MAPKs activation. In conclusion, this study demonstrates the protection of CGA against MCT-induced SOS. Transcriptional factor NFκB, Egr1 and Nrf2-regulated inflammation, coagulation-fibrinolysis, and antioxidant, and PI3K and MAPKs all contribute to such protection.