Cytokine-mediated transcriptional induction of the human inducible nitric oxide synthase gene requires both activator protein 1 and nuclear factor kappaB-binding sites

Amino Derivatives of Diaryl Pyrimidines and Azolopyrimidines as Protective Agents against LPS-Induced Acute Lung Injury

The problem of lung damage originating from excessive inflammation and cytokine release during various types of infections remains relevant and stimulates the search for highly effective and safe drugs. The biological activity of the latter may be associated with the regulation of hyperactivation of certain immune cells and enzymes. Here, we propose the design and synthesis of amino derivatives of 4,6- and 5,7-diaryl substituted pyrimidines and [1,2,4]triazolo[1,5-a]pyrimidines as promising double-acting pharmacophores inhibiting IL-6 and NO. The anti-inflammatory activity of 14 target compounds was studied on isolated primary murine macrophages after LPS stimulation. Seven compounds were identified to inhibit the synthesis of nitric oxide and interleukin 6 at a concentration of 100 µM. The most active compounds are micromolar inhibitors of IL-6 secretion and NO synthesis, showing a minimal impact on innate immunity, unlike the reference drug dexamethasone, along with acceptable cytotoxicity. Evaluation in an animal model of acute lung injury proved the protective activity of compound 6e, which was supported by biochemical, cytological and morphological markers.

Sargahydroquinoic acid isolated from Sargassum serratifolium as inhibitor of cellular basophils activation and passive cutaneous anaphylaxis in mice

Basophils and mast cells are characteristic effector cells in allergic reactions. Sargahydorquinoic acid (SHQA), a compound isolated from Sargassum serratifolium (marine alga), possesses various biochemical properties, including potent antioxidant activities. The objective of the present study was to investigate inhibitory effects of SHQA on the activation of human basophilic KU812F cells induced by phorbol myristate acetate and A23187 (PMACI), a calcium ionophore. Furthermore, we confirmed the inhibitory effects of SHQA on the activation of rat basophilic leukemia (RBL)-2H3 cells induced by compound 48/80 (com 48/80), bone marrow-derived mast cells (BMCMCs) induced by anti-dinitrophenyl(DNP)-immunoglobulin E (IgE)/DNP-bovine serum albumin (BSA), DNP/IgE and on the reaction of passive cutaneous anaphylaxis (PCA) mediated by IgE. SHQA reduced PMACI-induced intracellular reactive oxygen species (ROS) and calcium levels. Western blot analysis revealed that SHQA downregulated the activation of ERK, p38, and NF-κB in a dose-dependent manner. Moreover, SHQA suppressed the production and gene expression of various cytokines, including interleukin (IL)-1 β, IL-4, IL-6, and IL-8 in PMACI-induced KU812F cells and IL-4 and tumor necrosis factor (TNF)- α in com 48/80-induced RBL-2H3 cells. It also determined the inhibition of PMACI, com 48/80- and IgE/DNP-induced degranulation by reducing the release of β -hexosaminidase. Furthermore, it attenuated the IgE/DNP-induced PCA reaction in the ears of BALB/c mice. These results suggest that SHQA isolated from S. serratifolium is a potential therapeutic functional food material for inhibiting effector cell activation in allergic reactions and anaphylaxis in animal model.

Sargahydroquinoic Acid, a Cyclooxygenase-2 Inhibitor, Attenuates Inflammatory Responses by Regulating NF-κB Inactivation and Nrf2 Activation in Lipopolysaccharide-Stimulated Cells

Sargahydroquinoic acid (SHQA) is a major plastoquinone in Sargassum macrocarpum and has shown the capacity to prevent inflammation and oxidative stress. However, the protective mechanisms were unclear. The molecular mechanisms of SHQA on ameliorating inflammation and oxidative stress have been investigated, using lipopolysaccharide (LPS)-stimulated macrophages. SHQA was isolated and purified from S. macrocarpum and the anti-inflammatory mechanisms were explored using LPS-stimulated murine macrophage RAW 264.7 cells. SHQA did not change the expression of cyclooxygenase-2 (COX-2) but inhibited the activity of COX-2. As a result, SHQA significantly diminished the secretions of nitric oxide (NO), prostaglandin E2 (PGE2), and multiple pro-inflammatory cytokines. LPS-induced activation of nuclear factor-κB (NF-κB) was inhibited by SHQA by preventing the degradation of inhibitor κB-α (IκBα). NF-κB activation was also downregulated by the inhibition of Akt phosphorylation in LPS-stimulated cells. Furthermore, SHQA induced the expression of heme oxygenase 1 via Nrf2 activation. These results indicated that SHQA inhibited LPS-induced expressions of inflammatory mediators via suppressing the Akt-mediated NF-κB pathway as well as upregulating the Nrf2/HO-1 pathway. Our findings suggest that SHQA might be a potential therapeutic agent in various inflammatory diseases.

Participation of nitrogen oxide and its metabolites in the genesis of hyperimmune inflammation in COVID-19

Despite the success in the tactics of treating COVID-19, there are many unexplored issues related to the development and progression of the process in the lungs, brain, and other organs, as well as the role of individual elements, in particular, nitric oxide (NO), and in the pathogenesis of organ damage. Based on the analyzed literature data, we considered a possible pathophysiological mechanism of action of NO and its derivatives in COVID-19. It can be noted that hyperimmune systemic inflammation and "cytokine storm" are enhanced by the production of NO, products of its oxidation ("nitrosative stress"). It is noted in the work that as a result of the oxidation of NO, a large amount of the toxic compound peroxynitrite is formed, which is a powerful proinflammatory agent. Its presence significantly damages the endothelium of the vascular walls and also oxidizes lipids, hemoglobin, myoglobin, and cytochrome, binds SH-groups of proteins, and damages DNA in the target cells. This is confirmed by the picture of the vessels of the lungs on computed tomography and the data of biochemical studies. In case of peroxynitrite overproduction, inhibition of the synthesis of NO and its metabolic products seems to be justified. Another aspect considered in this work is the mechanism of damage by the virus to the central and peripheral nervous system, which remains poorly understood but may be important in understanding the consequences, as well as predicting brain functions in persons who have undergone COVID-19. According to the analyzed literature, it can be concluded that brain damage is possible due to the direct effect of the virus on the peripheral nerves and central structures, and indirectly through the effect on the endothelium of cerebral vessels. Disturbances in the central nervous regulation of immune responses may be associated with the insufficient function of the acetylcholine anti-inflammatory system. It is proposed to further study several approaches to influence various links of NO exchange, which are of interest for theoretical and practical medicine.

Oxidative Stress Promotes Corticosteroid Insensitivity in Asthma and COPD

Corticosteroid insensitivity is a key characteristic of patients with severe asthma and COPD. These individuals experience greater pulmonary oxidative stress and inflammation, which contribute to diminished lung function and frequent exacerbations despite the often and prolonged use of systemic, high dose corticosteroids. Reactive oxygen and nitrogen species (RONS) promote corticosteroid insensitivity by disrupting glucocorticoid receptor (GR) signaling, leading to the sustained activation of pro-inflammatory pathways in immune and airway structural cells. Studies in asthma and COPD models suggest that corticosteroids need a balanced redox environment to be effective and to reduce airway inflammation. In this review, we discuss how oxidative stress contributes to corticosteroid insensitivity and the importance of optimizing endogenous antioxidant responses to enhance corticosteroid sensitivity. Future studies should aim to identify how antioxidant-based therapies can complement corticosteroids to reduce the need for prolonged high dose regimens in patients with severe asthma and COPD.

Design, synthesis, and molecular docking of novel 3,5-disubstituted-1,3,4-oxadiazole derivatives as iNOS inhibitors

To obtain new anti-inflammatory agents, recent studies have aimed to replace the carboxylate functionality of nonsteroidal anti-inflammatory drugs with less acidic heterocyclic bioisosteres like 1,3,4-oxadiazole to protect the gastric mucosa from free carboxylate moieties. In view of these observations, we designed and synthesized a series of 3,5-disubstituted-1,3,4-oxadiazole derivatives as inhibitors of prostaglandin E₂ (PGE₂ ) and NO production with an improved activity profile. As initial screening, and to examine the anti-inflammatory activities of the compounds, the inhibitions of the productions of lipopolysaccharide-induced NO and PGE₂ in RAW 264.7 macrophages were evaluated. The biological assays showed that, compared with indomethacin, compounds 5a, 5g, and 5h significantly inhibited NO production with 12.61 ± 1.16, 12.61 ± 1.16, and 18.95 ± 3.57 µM, respectively. Consequently, the three compounds were evaluated for their in vivo anti-inflammatory activities. Compounds 5a, 5g, and 5h showed a potent anti-inflammatory activity profile almost equivalent to indomethacin at the same dose in the carrageenan-induced paw edema test. Moreover, the treatment with 40 mg/kg of 5h produced significant anti-inflammatory activity data. Furthermore, docking studies were performed to reveal possible interactions with the inducible nitric oxide synthase enzyme. Docking results were able to rationalize the biological activity data of the studied inhibitors. In summary, our data suggest that compound 5h is identified as a promising candidate for further anti-inflammatory drug development with an extended safety profile.

Anti-inflammatory Effects of Statins in Lung Vascular Pathology: From Basic Science to Clinical Trials

HMG-CoA reductase inhibitors (or statins) are cholesterol-lowering drugs and are among the most widely prescribed medications in the United States. Statins exhibit pleiotropic effects that extend beyond cholesterol reduction including anti-atherosclerotic, antiproliferative, anti-inflammatory, and antithrombotic effects. Over the last 20 years, statins have been studied and examined in pulmonary vascular disorders, including both chronic pulmonary vascular disease such as pulmonary hypertension, and acute pulmonary vascular endothelial injury such as acute lung injury. In both research and clinical settings, statins have demonstrated promising vascular protection through modulation of the endothelium, attenuation of vascular leak, and promotion of endothelial repair following lung inflammation. This chapter provides a summary of the rapidly changing literature, summarizes the anti-inflammatory mechanism of statins on pulmonary vascular disorders, and explores clinical evidence for statins as a potential therapeutic approach to modulation of the endothelium as well as a means to broaden our understanding of pulmonary vasculopathy pathophysiology.

Potential role of NF-κB pathway in the immuno-inflammatory responses during human cystic echinococcosis

Cystic echinococcosis (CE) induces in the human host innate and adaptive immune response that plays an important role in controlling the immunopathogenesis. Due to the crucial role of nuclear factor kappa B (NF-κB) in regulating immuno-inflammatory processes, we investigated its potential contribution in systemic and local immuno-inflammatory responses in primary CE patients and relapsed patients. The expression of NF-κB and inducible nitric oxide synthase (iNOS) was analyzed in peripheral blood mononuclear cells (PBMC) as well as in pericystic layer of pulmonary hydatid cysts from Algerian primary CE patients and relapsed patients. Tumor necrosis factor alpha (TNF-α) and nitric oxide (NO) production was evaluated in plasma samples. Our results showed high iNOS and NF-κB expression in both PBMCs and pericystic histiocytes from primary CE patients. In addition, substantial amounts of systemic NO and TNF-α were detected in the same patients. Remarkably, relapsed patients exhibited a low NF-κB and iNOS expression associated with low amounts of plasmatic TNF-α and NO. Collectively, NF-κB/iNOS pathway is involved in the host defense mechanisms at the systemic and local level during primary CE. Our results indicate that the inhibition of this pathway in relapsed patients will attenuate protective immunity and promote parasite escape. This study allowed to identify a novel predictive biomarkers of hydatidosis.

Sirt1-Overexpressing Mesenchymal Stem Cells Drive the Anti-tumor Effect through Their Pro-inflammatory Capacity

The major obstacles for the efficacy of tumor immunotherapies are their immune-related systemic adverse events. Therefore, tumor tropism property and pro-inflammatory ability of mesenchymal stem cells (MSCs) could be utilized in combination to potentiate local immunity for cancer eradication. We previously observed that MSCs with the type III histone deacetylase silent information regulator 2 homologue 1 (Sirt1) overexpression displayed a pro-inflammatory capacity. However, the anti-tumor effect of Sirt1-overexpressing MSCs and the role of Sirt1 in regulating the pro-inflammatory capacity of MSCs still need to be clarified. In this study, utilizing the hepatic metastasis model of colorectal carcinoma, we demonstrated that Sirt1-overexpressing MSCs significantly exerted anti-tumor activity through increasing the number of CD8⁺ T cells. Furthermore, Sirt1 did not affect chemokine secretion in MSCs induced by inflammatory cytokines, but impaired the immunosuppressive ability of MSCs through suppressing inflammatory cytokine-stimulated inducible nitric oxide synthase (iNOS) production via deacetylating p65. iNOS overexpression negated the anti-tumor effect of Sirt1-overexpressing MSCs. Collectively, our data defined Sirt1 as the critical regulator for modulating the pro-inflammatory ability of MSCs, and they suggested that Sirt1-overexpressing MSCs secreting chemokines but little iNOS under the inflammatory milieu were capable of attracting immune cells to close proximity without suppressing their proliferation, thereby achieving a potent anti-tumor effect.

Effects of dichloromethane Sarcophyton spp. extract on the lipopolysaccharide-induced expression of nuclear factor-kappa B and inducible nitric oxide synthase in mice

BACKGROUND AND AIM

The soft coral genus Sarcophyton is a source of cembraneterpen. Sarcophyton is reported to have anti-inflammatory properties, with the ability to reduce the expression of inducible nitric oxide synthase (iNOS) and inhibit nuclear factor-kappa B (NF-κB) activation. This study aimed to investigate the efficacy of dichloromethane (DCM) extracts of soft coral Sarcophyton spp. to inhibit the expression of NF-κB and iNOS induced by lipopolysaccharide (LPS).

MATERIALS AND METHODS

Crude extracts of Sarcophyton spp. were macerated with DCM (1:3 v/v) for 24 h. Thirty-six Balb/c mice were divided into six treatment groups, namely, normal control (without LPS induction), negative control (LPS induction 4 mg/mL), comparative control (LPS+Dexamethasone 6 mg/kg), and 3 concentration groups extract (LPS+50, 125, and 250 mg/kg). The expression of NF-κB and iNOS was measured in each treatment group.

RESULTS

Flow cytometry analysis showed that the relative number of NF-κB+ cells increased (18.38±1.24%) in LPS-induced mice compared with normal mice (13.24±1.15%). The Sarcophyton spp. DCM extracts decreased the relative number of NF-κB+ cells (125 mg/kg: 13.96±0.84%). Immunohistochemical analysis with ImmunoMembrane showed that LPS induction in mice increased iNOS expression when compared to normal mice. The Sarcophyton spp. DCM extracts reduced iNOS expression (especially at 125 mg/kg).

CONCLUSION

DCM extracts of Sarcophyton spp. inhibited the activation of NF-κB, resulting in suppressed iNOS expression, which directly inhibits NO production.

Phlorotannins from Undaria pinnatifida Sporophyll: Extraction, Antioxidant, and Anti-Inflammatory Activities

Undaria pinnatifida sporophyll (U. pinnatifida) is a major byproduct of U. pinnatifida (a brown algae) processing. Its phenolic constituents, phlorotannins, are of special interest due to their intrinsic ability to precipitate proteins. Herein, a high-temperature extraction procedure was used to isolate these biologically active compounds. The heating temperature, heating time, and extraction solvent (ethanol) concentration were examined with response surface analysis to determine the optimal conditions to achieve the maximum extraction rate. The analysis revealed the optimal conditions to be: 170 °C of heating temperature, 5.2 h of heating time, and 52% ethanol concentration for a yield of 10.7 ± 0.2 mg gallic acid equivalent/g dry weight (GAE/g DW) of sample. Compared to epigallocatechin gallate (EGCG), the extracted phlorotannins displayed higher antioxidant activity on H2O2-induced RAW 264.7 cells with improved efficiency. Furthermore, the compounds exhibited strong anti-inflammatory activity. These findings potentially can be utilized to guide development of novel functional foods and food supplements from sea-originated resources such as brown algae.

The Role of Nitric Oxide in Regulating Intestinal Redox Status and Intestinal Epithelial Cell Functionality

Important functions of intestinal epithelial cells (IECs) include enabling nutrient absorption to occur passively and acting as a defense barrier against potential xenobiotic components and pathogens. A compromise to IEC function can result in the translocation of bacteria, toxins, and allergens that lead to the onset of disease. Thus, the maintenance and optimal function of IECs are critically important to ensure health. Endogenous biosynthesis of nitric oxide (NO) regulates IEC functionality both directly, through free radical activity, and indirectly through cell signaling mechanisms that impact tight junction protein expression. In this paper, we review the current knowledge on factors that regulate inducible nitric oxide synthase (iNOS) and the subsequent roles that NO has on maintaining IECs' intestinal epithelial barrier structure, functions, and associated mechanisms of action. We also summarize important findings on the effects of bioactive dietary food components that interact with NO production and affect downstream intestinal epithelium integrity.

Expression of human inducible nitric oxide synthase in response to cytokines is regulated by hypoxia-inducible factor-1

The production of nitric oxide (NO) by inducible NO synthase (iNOS) and the regulation of gene expression by hypoxia-inducible factors (HIFs) are important for many aspects of human cell biology. However, little is known about whether iNOS expression is controlled by HIFs in human cells. Stimulation of A549 human lung epithelial cells with cytokines (TNF, IL-1 and IFNγ) increased the nuclear accumulation of HIF-1 in normoxic conditions. Activation of HIF-1 by hypoxia or CoCl₂ was not sufficient to induce iNOS expression. However, pharmacological inhibition of HIF-1 reduced the induction of iNOS expression in A549 cells and primary human astrocytes. Moreover, elimination of HIF-1α expression and activity by CRISPR/Cas9 gene editing significantly reduced the induction of human iNOS gene promoter, mRNA and protein expression by cytokine stimulation. Three putative hypoxia response elements (HRE) are present within the human iNOS gene promoter and elimination of an HRE at -4981 bp reduced the induction of human iNOS promoter activity in response to cytokine stimulation. These findings establish an important role for HIF-1α in the induction of human iNOS gene expression in response to cytokine stimulation.

The Signaling Pathways in Nitric Oxide Production by Neutrophils Exposed to N-nitrosodimethylamine

Background:

Polymorphonuclear neutrophils (PMNs) play a crucial role in the innate immune system’s response to microbial pathogens through the release of reactive nitrogen species, including Nitric Oxide (NO). </P><P> Methods: In neutrophils, NO is produced by the inducible Nitric Oxide Synthase (iNOS), which is regulated by various signaling pathways and transcription factors. N-nitrosodimethylamine (NDMA), a potential human carcinogen, affects immune cells. NDMA plays a major part in the growing incidence of cancers. Thanks to the increasing knowledge on the toxicological role of NDMA, the environmental factors that condition the exposure to this compound, especially its precursors- nitrates arouse wide concern.

Results:

In this article, we present a detailed summary of the molecular mechanisms of NDMA’s effect on the iNOS-dependent NO production in human neutrophils.

Conclusion:

This research contributes to a more complete understanding of the mechanisms that explain the changes that occur during nonspecific cellular responses to NDMA toxicity.

HX600, a synthetic agonist for RXR-Nurr1 heterodimer complex, prevents ischemia-induced neuronal damage

Ischemic stroke is amongst the leading causes of death and disabilities. The available treatments are suitable for only a fraction of patients and thus novel therapies are urgently needed. Blockage of one of the cerebral arteries leads to massive and persisting inflammatory reaction contributing to the nearby neuronal damage. Targeting the detrimental pathways of neuroinflammation has been suggested to be beneficial in conditions of ischemic stroke. Nuclear receptor 4A-family (NR4A) member Nurr1 has been shown to be a potent modulator of harmful inflammatory reactions, yet the role of Nurr1 in cerebral stroke remains unknown. Here we show for the first time that an agonist for the dimeric transcription factor Nurr1/retinoid X receptor (RXR), HX600, reduces microglia expressed proinflammatory mediators and prevents inflammation induced neuronal death in in vitro co-culture model of neurons and microglia. Importantly, HX600 was protective in a mouse model of permanent middle cerebral artery occlusion and alleviated the stroke induced motor deficits. Along with the anti-inflammatory capacity of HX600 in vitro, treatment of ischemic mice with HX600 reduced ischemia induced Iba-1, p38 and TREM2 immunoreactivities, protected endogenous microglia from ischemia induced death and prevented leukocyte infiltration. These anti-inflammatory functions were associated with reduced levels of brain lysophosphatidylcholines (lysoPCs) and acylcarnitines, metabolites related to proinflammatory events. These data demonstrate that HX600 driven Nurr1 activation is beneficial in ischemic stroke and propose that targeting Nurr1 is a novel candidate for conditions involving neuroinflammatory component.

Biflavonoids Isolated from Selaginella tamariscina and Their Anti-Inflammatory Activities via ERK 1/2 Signaling

Selaginella tamariscina (S. tamariscina) (Beauv.) Spring (Selaginellaceae) has been used in oriental medicine for the treatment of dysmenorrhea, chronic hepatitis, hyperglycemia, amenorrhea, hematuria, prolapse of the anus and metrorrhagia. In the present study, we isolated two strong anti-inflammatory compounds, the biflavonoids hinokiflavone (H) and 7′-O-methyl hinokiflavone (mH), from S. tamariscina and examined their anti-inflammatory activities in lipopolysaccharide (LPS)-mediated murine macrophages (RAW 264.7) and colon epithelial cells (HT-29). H and mH suppressed the production of the inflammatory mediators nitric oxide (NO), interleukin (IL)-6, IL-8, and tumor-necrosis factor (TNF)-α, which are most highly activated in inflammatory bowel disease (IBD). In addition, Western blot analysis revealed that H and mH suppressed the LPS-induced expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2, and the activation of nuclear factor-κB (NF-κB) and extracellular regulated kinases (ERK) 1/2. These results suggest that H and mH are compounds having potent anti-inflammatory effects that could be used to treat such diseases as IBD.

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.

Novel Small Molecule Inhibitors of Protein Kinase D Suppress NF-kappaB Activation and Attenuate the Severity of Rat Cerulein Pancreatitis

Nuclear factor-kappa B (NF-κB) activation is a key early signal regulating inflammatory and cell death responses in acute pancreatitis. Our previous in vitro studies with molecular approaches on AR42J cell showed that protein kinase D (PKD/PKD1) activation was required in NF-κB activation induced by cholecystokinin 8 (CCK) or carbachol (CCh) in pancreatic acinar cells. Recently developed small molecule PKD inhibitors, CID755673 and CRT0066101, provide potentially important pharmacological approaches to further investigate the effect of PKD in pancreatitis therapy. The aim of this study was to explore whether CID755673 and CRT0066101 block NF-κB activation with in vitro and in vivo models of experimental pancreatitis and whether the small molecule PKD inhibitors have therapeutic effects when given before or after the initiation of experimental pancreatitis. Freshly prepared pancreatic acini were incubated with CID755673 or CRT006101, followed by hyperstimulation with CCK or CCh. For in vivo experimental pancreatitis, rats were treated with intraperitoneal injection of CID755673 or CRT0066101 prior to or after administering cerulein or saline. PKD activation and NF-κB-DNA binding activity in nuclear extracts from pancreatic acini and tissue were measured. The effects of PKD inhibitors on pancreatitis responses were evaluated. Our results showed that both CID755673 or CRT0066101 selectively and specifically inhibited PKD without effects on related protein kinase Cs. Inhibition of PKD resulted in significantly attenuation of NF-κB activation in both in vitro and in vivo models of experimental pancreatitis. NF-κB inhibition by CID755673 was associated with decreased inflammatory responses and attenuated severity of the disease, which were indicated by less inflammatory cell infiltration, reduced pancreatic interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1), decreased intrapancreatic trypsin activation, and alleviation in pancreatic necrosis, edema and vacuolization. Furthermore, PKD inhibitor CID755673, given after the initiation of pancreatitis in experimental rat model, significantly attenuated the severity of acute pancreatitis. Therapies for acute pancreatitis are limited. Our results indicate that small chemical PKD inhibitors have significant potential as therapeutic interventions by suppressing NF-κB activation.

Effects of SPAK on vascular reactivity and nitric oxide production in endotoxemic mice

Vasoplegia impedes therapeutic interventions to restore vascular tone, leading to severe hypotension, poor tissue perfusion, and multiple organ failure in septic shock. High levels of circulating nitric oxide (NO) play a crucial role in endotoxin-induced vascular hyporeactivity. Proinflammatory cytokines have been implicated in the induction of inducible NO synthase and overproduction of NO. Anti-inflammatory therapy can diminish NO formation and improve vascular hyporeactivity in septic shock. STE20/SPS1-realted proline/alanine-rich kinase (SPAK) has been reported to activate mitogen-activated protein kinase and contribute to intestinal inflammation. Thus, we evaluated the roles of SPAK in NO production and vascular hyporeactivity in endotoxemic animals. Male wild-type and SPAK deficiency mice were intraperitoneally administered vehicle or Escherichia coli lipopolysaccharide (LPS, 50mg/kg). The changes of systolic blood pressure and plasma nitrate and nitrite levels were measured during the experimental period. Thoracic aortas were exercised to assess vascular reactivity and SPAK expression. In the present study, mice in endotoxin model showed severe hypotension and hyporeactivity to serotonin, phenylephrine (PE), and acetylcholine in the aortic rings. Phosphorylated SPAK expression in the aorta and NO levels in the plasma were also increased in animals with endotoxic shock. However, deletion of SPAK not only reduced the elevation of NO levels but also improved vascular hyporeactivity to serotonin and PE in endotoxemic mice. Taken together, SPAK could be involved in the NO overproduction and vascular hyporesponsiveness to vasoconstrictors in endotoxic shock. Thus, inhibition of SPAK could be useful in the prevention of endotoxin-induced vascular hyporeactivity.

Immunobiology of Nitric Oxide and Regulation of Inducible Nitric Oxide Synthase

Nitric oxide (NO) is a bioactive gas that has multiple roles in innate and adaptive immune responses. In macrophages, nitric oxide is produced by inducible nitric oxide synthase upon microbial and cytokine stimulation. It is needed for host defense against pathogens and for immune regulation. This review will summarize the role of NO and iNOS in inflammatory and immune responses and will discuss the regulatory mechanisms that control inducible nitric oxide synthase expression and activity.

Epigenetic regulation of nitric oxide synthase 2, inducible (Nos2) by NLRC4 inflammasomes involves PARP1 cleavage

Nitric oxide synthase 2, inducible (Nos2) expression is necessary for the microbicidal activity of macrophages. However, NOS2 over-activation causes multiple inflammatory disorders, suggesting a tight gene regulation is necessary. Using cytosolic flagellin as a model for inflammasome-dependent NOS2 activation, we discovered a surprising new role for NLRC4/caspase-1 axis in regulating chromatin accessibility of the Nos2 promoter. We found that activation of two independent mechanisms is necessary for NOS2 expression by cytosolic flagellin: caspase-1 and NF-κB activation. NF-κB activation was necessary, but not sufficient, for NOS2 expression. Conversely, caspase-1 was necessary for NOS2 expression, but dispensable for NF-κB activation, indicating that this protease acts downstream NF-κB activation. We demonstrated that epigenetic regulation of Nos2 by caspase-1 involves cleavage of the chromatin regulator PARP1 (also known as ARTD1) and chromatin accessibility of the NF-κB binding sites located at the Nos2 promoter. Remarkably, caspase-1-mediated Nos2 transcription and NO production contribute to the resistance of macrophages to Salmonella typhimurium infection. Our results uncover the molecular mechanism behind the constricted regulation of Nos2 expression and open new therapeutic opportunities based on epigenetic activities of caspase-1 against infectious and inflammatory diseases.

Lipopolysaccharide (LPS)-stimulated iNOS Induction Is Increased by Glucosamine under Normal Glucose Conditions but Is Inhibited by Glucosamine under High Glucose Conditions in Macrophage Cells

We investigated the regulatory effect of glucosamine (GlcN) for the production of nitric oxide (NO) and expression of inducible NO synthase (iNOS) under various glucose conditions in macrophage cells. At normal glucose concentrations, GlcN dose dependently increased LPS-stimulated production of NO/iNOS. However, GlcN suppressed NO/iNOS production under high glucose culture conditions. Moreover, GlcN suppressed LPS-induced up-regulation of COX-2, IL-6, and TNF-α mRNAs under 25 mm glucose conditions yet did not inhibit up-regulation under 5 mm glucose conditions. Glucose itself dose dependently increased LPS-induced iNOS expression. LPS-induced MAPK and IκB-α phosphorylation did not significantly differ at normal and high glucose conditions. The activity of LPS-induced nuclear factor-κB (NF-κB) and DNA binding of c-Rel to the iNOS promoter were inhibited under high glucose conditions in comparison with no significant changes under normal glucose conditions. In addition, we found that the LPS-induced increase in O-GlcNAcylation as well as DNA binding of c-Rel to the iNOS promoter were further increased by GlcN under normal glucose conditions. However, both O-GlcNAcylation and DNA binding of c-Rel decreased under high glucose conditions. The NF-κB inhibitor, pyrrolidine dithiocarbamate, inhibited LPS-induced iNOS expression under high glucose conditions but it did not influence iNOS induction under normal glucose conditions. In addition, pyrrolidine dithiocarbamate inhibited NF-κB DNA binding and c-Rel O-GlcNAcylation only under high glucose conditions. By blocking transcription with actinomycin D, we found that stability of LPS-induced iNOS mRNA was increased by GlcN under normal glucose conditions. These results suggest that GlcN regulates inflammation by sensing energy states of normal and fuel excess.

Anti-Inflammatory Effect of Ethanolic Extract of Sargassum serratifolium in Lipopolysaccharide-Stimulated BV2 Microglial Cells

Sargassum serratifolium was found to contain high concentrations of meroterpenoids, having strong antioxidant, anti-inflammatory, and neuroprotective activities. This study aims to investigate the anti-inflammatory mechanisms of an ethanolic extract of S. serratifolium (ESS) using lipopolysaccharide (LPS)-stimulated BV2 microglial cells and to identify the anti-inflammatory components in ESS. The level of proinflammatory cytokines was measured by enzyme-linked immunosorbent assay. The expression of inflammation-related proteins and mRNA was evaluated by Western blot and reverse transcription-polymerase chain reaction analysis, respectively. Anti-inflammatory activities of isolated components from ESS were analyzed in LPS-stimulated BV2 cells. ESS inhibited LPS-induced nitric oxide (NO) and prostaglandin E2 and the expression of inducible NO synthase and cyclooxygenase-2. ESS also decreased the release of proinflammatory cytokines in a dose-dependent manner. LPS-induced nuclear factor-kappa B (κB) transcriptional activity and translocation into the nucleus were remarkably suppressed by ESS through the prevention of inhibitor κB-α degradation. The main anti-inflammatory components in ESS were identified as sargahydroquinoic acid, sargachromenol, and sargaquinoic acid based on the inhibition of NO production using LPS-stimulated BV2 cells. Furthermore, treatment with ESS significantly reduced levels of tumor necrosis factor-α and interleukin-1β stimulated with LPS in mouse hippocampus. Our results indicate that ESS can be used as a functional food or therapeutic agent for the treatment of neuroinflammatory diseases.

Evaluation of iNOS Expression in Esophageal Cancer Patients

BACKGROUND

Esophageal cancer is a public health concern around the world; this cancer is the sixth leading cause of death of cancer in the world with about 386,000 deaths per year. Its risk factors include environmental factors such as tobacco smoke, gastroesophageal reflux and genetic changes. iNOS is stated by the effect of various inflammatory factors and is thus called inducible NOS. Investigating iNOS expression is a powerful tool for understanding effective molecular parameters at tissue and cellular responses to external factors. In this research work, iNOS expression in patients with esophageal cancer was studied in Iran.

MATERIALS AND METHODS

15 formalin-fixed and paraffin-embedded (FFPE) esophageal cancer tissue samples and 15 normal FFPE samples were collected from various medical centers (Zabol, Zahedan, Kashan) to measure iNOS expression by real-time reverse transcriptase polymerase chain reaction (real-time RT-PCR). All PCR reactions were conducted by three replicates for iNOS and internal control (β-actin) by 2-ΔΔCT (Livak) method. Differences were measured in target gene expression in patients and control group using the t test. All statistical analyses were done using the SPSS software.

RESULTS

The results showed that there was no significant difference between iNOS expression in the case and control groups (p > 0.05); however, there was an increase in iNOS expression in the case group. On the other hand, there was a significant difference between iNOS expression in males and females in the two groups of healthy subjects and patients, and it was higher in women than in men.

CONCLUSION

Further studies need to be conducted with larger sample sizes and in other populations to validate these findings.

Longan (Dimocarpus longan Lour.) inhibits lipopolysaccharide-stimulated nitric oxide production in macrophages by suppressing NF-κB and AP-1 signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Flower, seed, and fruit of longan (Dimocarpus longan Lour.) have been used in the Traditional Chinese Medicine (TCM) serving as a common herb in relief of swelling which can be applied in cases of inflammatory diseases. However, the scientific evidence related to their effects on inflammation especially the possible cellular and molecular mechanisms of longan need to be clarified.

AIM OF THE STUDY

To evaluate the anti-inflammatory effect of the various parts of longan including flower, seed, and pulp. The mechanisms and molecular targets involved in their effects were also investigated.

MATERIALS AND METHODS

Different longan extracts were analyzed for their bioactive compounds and evaluated for anti-inflammation. Corilagin, ellagic acid, and gallic acid were detected using HPLC-DAD. In vitro anti-inflammatory effect of longan extracts and their polysaccharides were examined by analyzing nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Expression of the proteins that involved in NO production was detected by Western blot.

RESULTS

Flower extract contained the highest amounts of total phenolics, total flavonoids, proanthocyanidins, corilagin and ellagic acid when compared to seed and pulp extracts. The extracts of different longan parts inhibited LPS-induced NO production with different potency. The highest potency for the inhibition of NO production was shown with flower extract follow by seed and pulp (IC50=128.2, 1127.4, and 1260.2μgmL(-1), respectively). The mechanisms of this anti-NO production were associated with their NO scavenging effect and their decreasing the expression and catalytic activity of an inducible nitric oxide synthase (iNOS). Moreover, these longan extracts suppressed LPS-induced degradation of IκBα and activation of NF-κB, activator protein-1 (AP-1), Akt, and mitogen activated protein kinases (MAPKs).

CONCLUSION

These results suggest that the longan extracts possess anti-inflammatory property. Therefore, longan could provide potential dietary supplement for the treatment of inflammatory-related diseases.

Discovery of anti-inflammatory components from Guge Fengtong tablet based on inflammatory markers and exploration of its molecular mechanism

In this work, we discovered GGFTT and its bioactive combinatorial components (10C) could significantly decrease the production of TNF-α, IL-1β, IL-6. 10C exert comparable anti-inflammatory effect through NF-κB and MAPKs signaling pathways as GGFTT.

Sargaquinoic acid attenuates inflammatory responses by regulating NF-κB and Nrf2 pathways in lipopolysaccharide-stimulated RAW 264.7 cells

Myagropsis myagroides, a brown alga, showed strong anti-inflammatory activities in the previous studies. In this study, we isolated a strong anti-inflammatory compound, sargaquinoic acid (SQA), from M. myagroides and investigated the anti-inflammatory action using lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. SQA suppressed the production of inducible nitric oxide synthase and cyclooxygenase-2 in LPS-stimulated cells as well as that of reactive oxygen species. As a result, SQA inhibited the production of NO, prostaglandin E2, and pro-inflammatory cytokines. LPS-induced transcriptional activation of nuclear factor-κB (NF-κB) was remarkably inhibited by SQA treatment through the prevention of inhibitor κB-α degradation. The regulation of NF-κB activation was also mediated by the phosphorylation of ERK and Akt in LPS-stimulated RAW 264.7 cells. Moreover, SQA induced the production of heme oxygenase 1 via activation of transcription factor Nrf2. These results indicate that SQA inhibits the LPS-induced expression of inflammatory mediators via suppression of ERK and Akt-mediated NF-κB pathway as well as up-regulation of Nrf2/HO-1 pathway, indicating that SQA has a potential therapeutic and preventive application in various inflammatory diseases.

Pyranocoumarins from Root Extracts of Peucedanum praeruptorum Dunn with Multidrug Resistance Reversal and Anti-Inflammatory Activities

In the search for novel herbal-based anticancer agents, we isolated a new angular-type pyranocoumarin, (+)-cis-(3′S,4′S)-3′-angeloyl-4′-tigloylkhellactone (1) along with 12 pyranocoumarins (2–13), two furanocoumarins (14, 15), and a polyacetylene (16) were isolated from the roots of Peucedanum praeruptorum using chromatographic separation methods. The structures of the compounds were determined using spectroscopic analysis with nuclear magnetic resonance (NMR) and high-resolution-electrospray ionization-mass spectrometry (HR-ESI-MS). The multidrug-resistance (MDR) reversal and anti-inflammatory effects of all the isolated compounds were evaluated in human sarcoma MES-SA/Dx5 and lipopolysaccharide (LPS)-induced RAW 264.7 cells. Among the 16 tested compounds, two (2 and 16) downregulated nitric oxide (NO) production and five (1, 7, 8, 11, and 13) inhibited the efflux of drugs by MDR protein, indicating the reversal of MDR. Therefore, these compounds may be potential candidates for the development of effective agents against MDR forms of cancer.

Inhibitory effects of Chikusetsusaponin IVa on lipopolysaccharide-induced pro-inflammatory responses in THP-1 cells

This study investigated anti-inflammatory effects and possible mechanisms of Chikusetsusaponin IVa (Chi IVa), one of the main bioactive components in saponins from Panacis japonica (SPJ), which is used in traditional Tujia and Hmong Chinese medicine. To this end, changes in the inflammatory profiles of lipopolysacchride (LPS)-stimulated phrobol 12-myristate 13-acetate(PMA)-differented THP-1 macrophages were evaluated following Chi IVa treatment. The results showed that Chi IVa markedly decreased the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin-1 beta (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) at both the mRNA and protein level, which proved to be dose-dependent. Further studies revealed that Chi IVa strongly suppressed NF-κB activation and downregulated the phosphorylation of ERK, p38, and JNK. Our present study demonstrates that Chi IVa suppresses the production of iNOS, COX-2, IL-1β, IL-6, and TNF-α in LPS-stimulated THP-1 cells likely by inhibiting NF-κB activation and ERK, JNK, and p38 signal pathway phosphorylation.

Tat-CBR1 inhibits inflammatory responses through the suppressions of NF-κB and MAPK activation in macrophages and TPA-induced ear edema in mice

Human carbonyl reductase 1 (CBR1) plays a crucial role in cell survival and protects against oxidative stress response. However, its anti-inflammatory effects are not yet clearly understood. In this study, we examined whether CBR1 protects against inflammatory responses in macrophages and mice using a Tat-CBR1 protein which is able to penetrate into cells. The results revealed that purified Tat-CBR1 protein efficiently transduced into Raw 264.7 cells and inhibited lipopolysaccharide (LPS)-induced cyclooxygenase-2 (COX-2), nitric oxide (NO) and prostaglandin E2 (PGE2) expression levels. In addition, Tat-CBR1 protein leads to decreased pro-inflammatory cytokine expression through suppression of nuclear transcription factor-kappaB (NF-κB) and mitogen activated protein kinase (MAPK) activation. Furthermore, Tat-CBR1 protein inhibited inflammatory responses in 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced skin inflammation when applied topically. These findings indicate that Tat-CBR1 protein has anti-inflammatory properties in vitro and in vivo through inhibition of NF-κB and MAPK activation, suggesting that Tat-CBR1 protein may have potential as a therapeutic agent against inflammatory diseases.

Salicortin suppresses lipopolysaccharide-stimulated inflammatory responses via blockade of NF-κB and JNK activation in RAW 264.7 macrophages

We isolated the phenolic glucoside salicortin from a Populus euramericana bark extract, and examined its ability to suppress inflammatory responses as well as the molecular mechanisms underlying these abilities, using lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Salicortin inhibited iNOS expression and the subsequent production of NO in a dose-dependent manner in the LPS-stimulated RAW 264.7 cells. Salicortin significantly suppressed LPS-induced signal cascades of NF-κB activation, such as IKK activation, IκBα phosphorylation and p65 phosphorylation in RAW 264.7 cells. In addition, salicortin inhibited the LPS-induced activation of JNK, but not ERK or p38 MAPK. Furthermore, salicortin significantly inhibited production of pro-inflammatory cytokines, such as TNF-α, IL-1β and IL-6 in the LPS-stimulated RAW 264.7 cells. These findings suggest that salicortin may show its anti-inflammatory activity by suppressing the LPS-induced expression of pro-inflammatory mediators through inhibition of NF-κB and JNK MAPK signaling cascades in macrophages.

Modulatory effect of celastrol on Th1/Th2 cytokines profile, TLR2 and CD3+ T-lymphocyte expression in a relapsing-remitting model of multiple sclerosis in rats

Multiple sclerosis (MS) is an autoimmune inflammatory demyelinating disease of brain and spinal cord that has an increasing incidence worldwide and classically presents in a relapsing-remitting form. This study was designed to induce a relapsing-remitting model of experimental autoimmune encephalomyelitis (EAE) to investigate the possible modulatory effect of celastrol on Th1/Th2 cytokines profile, immunohistochemical expression of TLR2, and CD3+T-lymphocytic count. Eighteen female Sprague Dawley rats were divided into 3 groups; where group I served as normal control, group II as EAE+vehicle, and group III as EAE treated by celastrol (1mg/kg/day, i.p.) started at 10th day till 42nd day post-immunization. The clinical score of rats in group II (EAE+vehicle) was relapsed after the re-challenge at the 35th day post-immunization and exhibited significant positive association with serum TNF-α, NF-κB expression and nitrites levels in brain and spinal cord, and CD3+ T-lymphocytic count in brain tissues while serum IL-10 showed significant negative association. Treatment of EAE by celastrol caused amelioration of the clinical score and inhibited the relapse. It caused significant shift in cytokines profile from Th1 by decrease in TNF-α towards Th2 pattern by increase in IL-10. Moreover, celastrol treatment resulted in significant reduction in NF-κB expression, nitrites levels, as well as immunohistochemical expression of TLR2 and CD3+ T-lymphocytic count. The beneficial effect of celastrol was further confirmed histopathologically by reduction in H&E score. Collectively, these results provide a promising pre-clinical evidence and conclusion about use of celastrol in treatment of multiple sclerosis that must be accessed in further clinical studies.

Anti-inflammatory activity of methanol extract and n-hexane fraction mojabanchromanol b from Myagropsis myagroides

AIMS

This study was carried out to verify the anti-inflammatory effect of methanol extract from Myagropsis myagroides (MMME) and its n-hexane fraction mojabanchromanol b.

MAIN METHODS

The murine macrophages Raw264.7 cells were used. The pro-inflammatory cytokines (IL-6, IL-1β, TNF-α) and the expression of iNOS, COX-2, and NF-κB p65 were examined by ELISA and immunoblotting. To investigate the inhibitory effect of MMME in an animal model of inflammation, an assay to determine croton oil-induced ear edema in mice was performed.

KEY FINDINGS

NO levels decreased with increasing concentration of MMME, and were inhibited up to 50%. The secretion of IL-6, TNF-α, and IL-1β was suppressed in a dose-dependent manner, especially at 50μg/mL, inhibition activities of cytokines were over 50%. MMME also suppressed the expression of COX-2, iNOS, and NF-κB p65, suggesting that MMME could affect the expression of inflammation related cytokines and proteins through the deregulation of NF-κB. Moreover, the formation of mouse ear edema was reduced at the highest dose tested compared to that in the control, and generated similar effects compared with prednisolone at 250mg/kg in mice ear edema evaluation test. In addition, the results in photomicrograph of mice ear tissue and mast cells also showed the same effect. After purification of fractions of MMME, it indicated that n-hexane fraction mojabanchromanol b was the most active fraction showing the inhibitory effect of IL-6 and TNF-α.

SIGNIFICANCE

These results suggested that MMME and mojabanchromanol b may have great effects on inflammatory factors and be potential anti-inflammatory therapeutic materials.

Anthocyanin-rich fractions from red raspberries attenuate inflammation in both RAW264.7 macrophages and a mouse model of colitis

Edible berries have a broad spectrum of biomedical functions, including improving immune responses and reducing risk for chronic diseases. In this study, the anti-inflammatory activities of crude extracts (CEs), anthocyanin-rich fractions (ARFs), and des-anthocyanin fractions (DAFs) from seven berries were evaluated based on their inhibitory effects on nitric oxide (NO) production in lipopolysaccharide (LPS)/IFN-γ-activated RAW264.7 macrophages. ARFs from red raspberries (RR-ARFs) exhibited the highest efficiency in suppressing NO synthesis. The anti-inflammatory properties were also demonstrated by reducing the expression levels of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin-1 beta (IL-1β) and IL-6 in RAW264.7 cells. The luciferase reporter assay demonstrated that the activities of NF-κB and AP-1 signaling pathways were significantly suppressed by RR-ARFs. Further studies showed that RR-ARFs decreased the phosphorylation of IKK, IκBα, p65 and JNK and the nuclear translocation of p65 in LPS/IFN-γ-stimulated RAW264.7 cells. In a mouse colitis model, dextran sulfate sodium (DSS)-induced weight loss and histological damage were significantly ameliorated by RR-ARFs treatment. Taken together, our results indicate that RR-ARFs attenuate inflammation both in vitro and in vivo primarily by inhibiting the activation of NF-κB and MAPKs. The anti-inflammatory of RR-ARFs could be harnessed and applied in animal agriculture, drug and food industries.

Anti-inflammatory effects of progesterone in lipopolysaccharide-stimulated BV-2 microglia

Female sex is associated with improved outcome in experimental brain injury models, such as traumatic brain injury, ischemic stroke, and intracerebral hemorrhage. This implies female gonadal steroids may be neuroprotective. A mechanism for this may involve modulation of post-injury neuroinflammation. As the resident immunomodulatory cells in central nervous system, microglia are activated during acute brain injury and produce inflammatory mediators which contribute to secondary injury including proinflammatory cytokines, and nitric oxide (NO) and prostaglandin E₂ (PGE₂), mediated by inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2), respectively. We hypothesized that female gonadal steroids reduce microglia mediated neuroinflammation. In this study, the progesterone’s effects on tumor necrosis factor alpha (TNF-α), iNOS, and COX-2 expression were investigated in lipopolysaccharide (LPS)-stimulated BV-2 microglia. Further, investigation included nuclear factor kappa B (NF-κB) and mitogen activated protein kinase (MAPK) pathways. LPS (30 ng/ml) upregulated TNF-α, iNOS, and COX-2 protein expression in BV-2 cells. Progesterone pretreatment attenuated LPS-stimulated TNF-α, iNOS, and COX-2 expression in a dose-dependent fashion. Progesterone suppressed LPS-induced NF-κB activation by decreasing inhibitory κBα and NF-κB p65 phosphorylation and p65 nuclear translocation. Progesterone decreased LPS-mediated phosphorylation of p38, c-Jun N-terminal kinase and extracellular regulated kinase MAPKs. These progesterone effects were inhibited by its antagonist mifepristone. In conclusion, progesterone exhibits pleiotropic anti-inflammatory effects in LPS-stimulated BV-2 microglia by down-regulating proinflammatory mediators corresponding to suppression of NF-κB and MAPK activation. This suggests progesterone may be used as a potential neurotherapeutic to treat inflammatory components of acute brain injury.

Anti-inflammatory effects of sargachromenol-rich ethanolic extract of Myagropsis myagroides on lipopolysaccharide-stimulated BV-2 cells

BACKGROUND

Excessive pro-inflammatory cytokine production from activated microglia contributes to neurodegenerative diseases, thus, microglial inactivation may delay the progress of neurodegeneration by attenuating the neuroinflammation. Among 5 selected brown algae, we found the highest antioxidant and anti-neuroinflammatory activities from Myagropsis myagroides ethanolic extract (MME) in lipopolysaccharide (LPS)-stimulated BV-2 cells.

METHODS

The levels of nitric oxide (NO), prostaglandin E2 (PGE2), and pro-inflammatory cytokines were measured by Griess assay and enzyme linked immunesorbent assay. The levels of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), mitogen-activated protein kinases (MAPKs), and Akt were measured using Western blot. Nuclear translocation and transcriptional activation of nuclear factor-κB (NF-κB) were determined by immunefluorescence and reporter gene assay, respectively.

RESULTS

MME inhibited the expression of iNOS and COX-2 at mRNA and protein levels, resulting in reduction of NO and PGE2 production. As a result, pro-inflammatory cytokines were reduced by MME. MME also inhibited the activation and translocation of NF-κB by preventing inhibitor κB-α (IκB-α) degradation. Moreover, MME inhibited the phosphorylation of extracellular signal regulated kinases (ERKs) and c-Jun N-terminal kinases (JNKs). Main anti-inflammatory compound in MME was identified as sargachromenol by NMR spectroscopy.

CONCLUSIONS

These results indicate that the anti-inflammatory effect of sargachromenol-rich MME on LPS-stimulated microglia is mainly regulated by the inhibition of IκB-α/NF-κB and ERK/JNK pathways.

The role of MAP kinases in the induction of iNOS expression in neutrophils exposed to NDMA: the involvement transcription factors

PURPOSE

The role of MAP kinases in the activation of AP-1 (c-Jun, c-Fos) and NF-κB p65 engaged in the regulation of iNOS expression in human neutrophils (PMNs) exposed to N-nitrosodimethylamine (NDMA) was analyzed in the study.

MATERIAL AND METHODS

The study included a group of 20 healthy individuals. Isolated human PMN were incubated in the presence of NDMA. Selective MAP kinases inhibitors were used. The expression of proteins in the cytoplasmic and nuclear fractions was assessed using Western blot method.

RESULTS

The results show that NDMA intensifies iNOS, c-Jun, NF-κB p65 and IκB-α expression in the analyzed PMNs. The blocking of the p38 pathway led to lower iNOS expression, and higher expression of c-Jun and c-Fos in the cytoplasmic fraction, and also lower c-Jun expression in the nuclear fraction of PMNs exposed to NDMA. A decrease in iNOS expression in the cytoplasmic fraction, and also c-Jun in both fractions of the examined cells, was observed as a result of JNK pathway inhibition. The blocking of the ERK5 pathway led to higher iNOS, c-Jun and c-Fos expression in the cytoplasmic fraction, and higher c-Jun expression in the nuclear fraction of PMNs exposed to NDMA. The study also demonstrated that blocking of the p38 and JNK pathways resulted in higher expression of NF-κB p65 and IκB-α in the cytoplasmic fraction and their lower expression in the nuclear fraction of these cells.

CONCLUSION

Our data indicate the role of MAP kinases p38 and JNK in the activation of c-Jun and NF-κB p65 transcription factors engaged in the regulation of iNOS expression in human neutrophils exposed to NDMA. However ERK5 kinase is not involved in the regulation of iNOS and NO production by those cells.

Human T cell leukemia virus type I tax-induced IκB-ζ modulates tax-dependent and tax-independent gene expression in T cells

Human T cell leukemia virus type I (HTLV-I) is the etiologic agent of adult T cell leukemia (ATL) and various inflammatory disorders including HTLV-I-associated myelopathy/tropical spastic paraparesis. HTLV-I oncoprotein Tax is known to cause permanent activation of many cellular transcription factors including nuclear factor-κB (NF-κB), cyclic adenosine 3',5'-monophosphate response element-binding protein, and activator protein 1 (AP-1). Here, we show that NF-κB-binding cofactor inhibitor of NF-κB-ζ (IκB-ζ) is constitutively expressed in HTLV-I-infected T cell lines and ATL cells, and Tax transactivates the IκB-ζ gene, mainly through NF-κB. Microarray analysis of IκB-ζ-expressing uninfected T cells demonstrated that IκB-ζ induced the expression of NF-κB. and interferon-regulatory genes such as B cell CLL/lymphoma 3 (Bcl3), guanylate-binding protein 1, and signal transducer and activator of transcription 1. The transcriptional activation domain, nuclear localization signal, and NF-κB-binding domain of IκB-ζ were required for Bcl3 induction, and IκB-ζ synergistically enhanced Tax-induced Bcl3 transactivation in an NF-κB-dependent manner. Interestingly, IκB-ζ inhibited Tax-induced NF-κB, AP-1 activation, and HTLV-I transcription. Furthermore, IκB-ζ interacted with Tax in vitro and this interaction was also observed in an HTLV-I-transformed T cell line. These results suggest that IκB-ζ modulates Tax-dependent and Tax-independent gene transcription in T cells. The function of IκB-ζ may be of significance in ATL genesis and pathogenesis of HTLV-I-associated diseases.

Zinc oxide nanoparticles impair bacterial clearance by macrophages

AIM

The extensive development of nanoparticles (NPs) and their widespread employment in daily life have led to an increase in environmental concentrations of substances that may pose a biohazard to humans. The aim of this work was to examine the effects of zinc oxide nanoparticles (ZnO-NPs) on the host's pulmonary immune system response to nontypeable Haemophilus influenzae (NTHi) infection.

MATERIALS & METHODS

A murine infection model was employed to assess pulmonary inflammation and bacterial clearance in response to exposure to ZnO-NPs. The molecular mechanisms underlying ZnO-NP-impaired macrophage activation were investigated.

RESULTS

Treatment with ZnO-NPs impaired macrophage activation, leading to a delay in NTHi clearance in the bronchial alveolar lavage fluids and lungs. Exposure to ZnO-NPs followed by NTHi challenge decreased levels of nitric oxide compared with NTHi infection alone. The effects of ZnO-NPs involved downregulation of NTHi-activated expression of inducible nitric oxide synthase and the translocation of active NF-kB into the nucleus.

CONCLUSION

These results demonstrate that exposure to ZnO-NPs can impair innate immune responses and attenuate macrophage responses to bacterial infection.

Anti-inflammatory effect of tricin 4'-O-(threo-β-guaiacylglyceryl) ether, a novel flavonolignan compound isolated from Njavara on in RAW264.7 cells and in ear mice edema

Although recent study has shown tricin 4'-O-(threo-β-guaiacylglyceryl) ether (TTGE), an isolated compound from Njavara rice, to have the most potent anti-inflammatory effects, the action mechanism has not been fully understood. Here, we examined the effect of TTGE on the inflammation and elucidated the potential mechanism. We demonstrated that TTGE significantly inhibited LPS-induced NO and ROS generation in RAW264.7 cells, which was correlated with the down-regulating effect of TTGE on the iNOS and COX-2 expression via NF-κB and STAT3. TPA-induced ear edema was also efficiently inhibited by the TTGE treatment. TTGE blocked the induction of iNOS and COX-2 through the regulation of NF-κB and STAT3, which could explain the reduced TPA-induced edema symptoms. Moreover, the introduction of ERK inhibitor abrogated the anti-inflammatory effect of TTGE via the recovery of NF-κB and STAT3 signalings. Taken together, these results suggest that TTGE has anti-inflammatory properties through down-regulation of NF-κB and STAT3 pathways.