Praeruptorin a inhibits lipopolysaccharide‐induced inflammatory response in murine macrophages through inhibition of NF‐κB pathway activation

Praeruptorin A (PA) is a pyranocoumarin compound isolated from the dried root of Peucedanum praeruptorum Dunn (Umbelliferae). However, the antiinflammatory effect of PA has not been reported. The present study investigated the antiinflammatory effect of PA in lipopolysaccharide (LPS)‐stimulated RAW 264.7 macrophage cells. PA significantly inhibited the LPS‐induced production of nitric oxide (NO), interleukin‐1β (IL‐1β) and tumor necrosis factor‐α (TNF‐α). The mRNA and protein expressions of inducible nitric oxide synthase (iNOS), IL‐1β and TNF‐α were also suppressed by this compound. Further study showed that PA decreased the cytoplasmic loss of inhibitor κB‐α (IκB‐α) protein and inhibited the translocation of NF‐κB from cytoplasm to nucleus. Taken together, the results suggest that PA may exert antiinflammatory effects in vitro in LPS‐stimulated RAW 264.7 macrophages through inhibition of NF‐κB signal pathway activation. Copyright © 2010 John Wiley & Sons, Ltd.     

Isoforskolin and forskolin attenuate lipopolysaccharide‐induced inflammation through TLR4/MyD88/NF‐κB cascades in human mononuclear leukocytes

The principal active component of isoforskolin (ISOF) is from the plant Coleus forskohlii, native to China, which has attracted much attention for its biological effects. We hypothesize that ISOF and forskolin (FSK) pretreatment attenuates inflammation induced by lipopolysaccharide (LPS) related to toll‐like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), and nuclear factor kappa B (NF‐κB) signaling. Mononuclear leukocytes (MLs) from healthy donors' blood samples were separated by using density gradient centrifugation. Protein levels of TLR4, MyD88, and NF‐κB were detected using western blot and inflammatory cytokines interleukin (IL) 1β, IL‐2, IL‐6, IL‐21, IL‐23, tumor necrosis factor (TNF) α, and TNF‐β were tested by enzyme‐linked immunosorbent assay and Quantibody array in MLs. Our results showed that LPS augmented the protein levels of TLR4, MyD88, and NF‐κB in MLs and the production of IL‐1β, IL‐2, IL‐6, IL‐21, IL‐23, TNF‐α, and TNF‐β in supernatants of MLs. Despite treatment with ISOF and FSK prior to LPS, the protein levels of TLR4, MyD88, NF‐κB, IL‐1β, IL‐2, IL‐6, IL‐21, IL‐23, TNF‐α, and TNF‐β in MLs were apparently decreased. roflumilast (RF) and dexamethasone (DM) had a similar effect on MLs with ISOF and FSK. Our results, for the first time, have shown that ISOF and FSK attenuate inflammation in MLs induced by LPS through down‐regulating protein levels of IL‐1β and TNF‐α, in which TLR4/MyD88/NF‐κB signal pathway could be involved.     

Myrislignan Attenuates Lipopolysaccharide‐induced Inflammation Reaction in Murine Macrophage Cells Through Inhibition of NF‐κB Signalling Pathway Activation

Myrislignan is a new kind of lignan isolated from Myristica fragrans Houtt. Its antiinflammatory effects have not yet been reported. In the present study, the antiinflammatory effects and the underlying mechanisms of myrislignan in lipopolysaccharide (LPS)‐induced inflammation in murine RAW 264.7 macrophage cells were investigated. Myrislignan significantly inhibited LPS‐induced production of nitric oxide (NO) in a dose‐dependent manner. It inhibited mRNA expression and release of interleukin‐6 (IL‐6) and tumour necrosis factor‐α (TNF‐α). This compound significantly inhibited mRNA and protein expressions of inducible NO synthase (iNOS) and cyclooxygenase‐2 (COX‐2) dose‐dependently in LPS‐stimulated macrophage cells. Further study showed that myrislignan decreased the cytoplasmic loss of inhibitor κB‐α (IκB‐α) protein and the translocation of NF‐κB from cytoplasm to the nucleus. Our results suggest that myrislignan may exert its antiinflammatory effects in LPS‐stimulated macrophages cells by inhibiting the NF‐κB signalling pathway activation. Copyright © 2012 John Wiley & Sons, Ltd.     

The ability of hydroxysafflor yellow a to attenuate lipopolysaccharide‐induced pulmonary inflammatory injury in mice

Hydroxysafflor yellow A (HSYA) is a component of the flower of Carthamus tinctorius L. The present study investigated whether HSYA could attenuate acute lung injury (ALI) induced by lipopolysaccharide (LPS) administration. Male Kunming mice were pretreated with HSYA 0.5 h prior to intraperitoneal application of LPS. Arterial blood gas, lung water content index, lung tissue myeloperoxidase (MPO) activity, mRNA expression of inflammatory cytokines, NF‐κBp65, p38 mitogen‐activated protein kinase (MAPK) and pathological changes in lung morphology were assessed. After LPS administration, all animals displayed increased arterial carbon dioxide partial pressure (PaCO₂), and decreased arterial oxygen partial pressure (PaO₂), arterial oxygen saturation (SO₂), HCO₃^? concentration and pH, which were ameliorated by pretreating the animals with HSYA. HSYA administration significantly attenuated inflammatory cell infiltration and alleviated pulmonary edema induced by LPS. Moreover, HSYA decreased NF‐κB p65 nuclear translocation, inhibited proinflammatory cytokine TNF‐α, IL‐1β and IL‐6 mRNA expression and promoted antiinflammatory cytokine IL‐10 gene expression following LPS injection. Pulmonary p38 MAPK phosphorylation was upregulated 4 h after LPS treatment, which could be suppressed by pretreatment with HSYA. These findings demonstrated the protective effect of HSYA against LPS‐induced acute lung injury, which is suggested to be associated with the inhibition of p38 MAPK, NF‐κB p65 activation and alteration of inflammatory cytokine expression. Copyright © 2010 John Wiley & Sons, Ltd.     

Chrysophanol attenuates airway inflammation and remodeling through nuclear factor‐kappa B signaling pathway in asthma

Chrysophanol (CHR), a purified active constituent extracted from Rheum palmatum L., possesses anti‐inflammatory activity. This study aimed to evaluate its effects on asthma‐associated airway inflammation and remodeling. BALB/c mice were sensitized and challenged by ovalbumin (OVA) and administrated with different doses of CHR. We found that CHR decreased OVA‐induced pulmonary inflammation: the levels of interleukin (IL)‐4, IL‐5, and IL‐13, tumor necrosis factor (TNF)‐α, and inducible nitric oxide synthase were downregulated. CHR also attenuated airway remodeling induced by OVA challenge—CHR inhibited pulmonary α‐smooth muscle actin expression. Moreover, both the nuclear translocation and activity of NF‐κB p65 were inhibited by CHR in the asthmatic lung. Enhanced autophagy was initiated in the lung by OVA challenge as evidenced by upregulated light chain 3 beta, autophagy‐related protein 5, and Beclin 1. CHR suppressed OVA‐induced alterations in these autophagy‐related molecules. In vitro, CHR (2 or 20 μM) was used to treat human pulmonary epithelial BEAS‐2B cells in the presence of 10 ng/ml recombinant TNF‐α. CHR not only exhibited the antiproliferation effect but also inhibited the activation of nuclear factor‐kappa B (NF‐kB) signaling pathway in TNF‐α‐treated BEAS‐2B cells. In conclusion, our study indicates that CHR has the potential to ameliorate asthma.     

Inhibitory effect of Thuja orientalis on TNF-α-induced vascular inflammation

Vascular inflammation is involved in the initiation and progression of vascular diseases including atherosclerosis. While conducting in vitro screening of 600 medicinal plant extracts, an aqueous extract of Thuja orientalis (ATO) was found to exhibit antiinflammatory activity in human umbilical vein endothelial cells (HUVEC). In the current study, the antiinflammatory activity of ATO and possible mechanisms for this were investigated in HUVEC. Preincubation with ATO (20 μg/mL) suppressed tumor necrosis factor‐α (TNF‐α)‐induced expression of adhesion molecules including intercellular adhesion molecule‐1 (ICAM‐1), vascular cell adhesion molecule‐1 (VCAM‐1) and E‐selectin at both the protein and mRNA levels. ATO also inhibited U937 monocyte adhesion to HUVEC stimulated by TNF‐α. In addition, ATO attenuated TNF‐α‐induced p65 NF‐κB translocation into the nucleus and phosphorylation of IκB‐α. Furthermore, ATO significantly inhibited TNF‐α‐induced intracellular reactive oxygen species (ROS) production. Overall, the present data suggest that ATO can suppress TNF‐α‐induced vascular inflammatory processes, possibly via inhibition of ROS and NF‐κB activation, in HUVEC. Copyright © 2010 John Wiley & Sons, Ltd.     

Polysaccharide extracted from Potentilla anserina L ameliorate acute hypobaric hypoxia‐induced brain impairment in rats

High altitude cerebral edema (HACE) is a high altitude malady caused by acute hypobaric hypoxia (AHH), in which pathogenesis is associated with oxidative stress and inflammatory cytokines. Potentilla anserina L is mainly distributed in Tibetan Plateau, and its polysaccharide possesses many physiological and pharmacological properties. In the present study, the protective effect and potential treatment mechanism of Potentilla anserina L polysaccharide (PAP) in HACE were explored. First, we measured the brain water content and observed the pathological changes in brain tissues, furthermore, malondialdehyde (MDA), nitric oxide (NO), superoxide dismutase (SOD), and glutathione (GSH) were evaluated by kits. Finally, the protein contents and mRNA expressions of pro‐inflammatory (IL‐1β, IL‐6, TNF‐α, vascular endothelial cell growth factor [VEGF], NF‐κB, and hypoxia inducible factor‐1 α [HIF‐1α]) were detected by ELISA kits, RT‐PCR, and western blotting. The results demonstrated that PAP reduced the brain water content, alleviated brain tissue injury, reduce the levels of MDA and NO, and increased the activity of SOD and GSH level. In addition, PAP blocking the NF‐κB and HIF‐1α signaling pathway activation inhibited the generation of downstream pro‐inflammatory cytokines (IL‐1β, IL‐6, TNF‐α, and VEGF). Therefore, PAP has a potential to treat and prevent of HACE by suppression of oxidative stress and inflammatory response.     

Diosmetin exhibits anti‐proliferative and anti‐inflammatory effects on TNF‐α‐stimulated human rheumatoid arthritis fibroblast‐like synoviocytes through regulating the Akt and NF‐κB signaling pathways

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by inflammation and proliferation of synovial tissues. Diosmetin is a bioflavonoid possessing an anti‐inflammatory property. Herein, we aimed to study the effects of diosmetin on the inflammation and proliferation of RA fibroblast‐like synoviocytes MH7A cells. MH7A cell proliferation was measured using cell counting kit‐8 assay. Cell apoptosis was examined using flow cytometry. The production of inflammatory cytokines including interleukin (IL)‐1β, IL‐6, IL‐8, and matrix metalloproteinase‐1 (MMP‐1) was measured using enzyme‐linked immunosorbent assay (ELISA). Results showed that diosmetin inhibited tumor necrosis factor‐α (TNF‐α)‐induced proliferation increase in MH7A cells in a dose‐dependent manner. Diosmetin treatment resulted in an increase in apoptotic rates and a reduction in TNF‐α‐induced production of IL‐1β, IL‐6, IL‐8, and MMP‐1 in MH7A cells. Furthermore, diosmetin inhibited TNF‐α‐induced activation of protein kinase B (Akt) and nuclear factor‐κB (NF‐κB) pathways in MH7A cells. Suppression of Akt or NF‐κB promoted apoptosis and inhibited TNF‐α‐induced proliferation increase and production of IL‐1β, IL‐6, IL‐8, and MMP‐1 in MH7A cells, and diosmetin treatment enhanced these effects. Taken together, these findings suggested that diosmetin exhibited anti‐proliferative and anti‐inflammatory effects via inhibiting the Akt and NF‐κB pathways in MH7A cells.     

Inhibition of TNF‐α‐Induced MUC5AC Mucin Gene Expression and Production by Wogonin Through the Inactivation of NF‐κB Signaling in Airway Epithelial Cells

In this study, we investigated whether wogonin significantly affects MUC5AC mucin gene expression and production in human airway epithelial cells. Confluent NCI‐H292 cells were pretreated with wogonin for 30 min and then stimulated with tumor necrosis factor‐α (TNF‐α) for 24 h or the indicated periods. The MUC5AC mucin gene expression and mucin protein production were measured by RT‐PCR and ELISA, respectively. We found that incubation of NCI‐H292 cells with wogonin significantly inhibited mucin production and down‐regulated MUC5AC gene expression induced by TNF‐α in a dose‐dependent fashion. To elucidate the action mechanism of wogonin, effect of wogonin on TNF‐α‐induced NF‐κB signaling pathway was investigated by western blot analysis. Wogonin inhibited NF‐κB activation induced by TNF‐α. Inhibition of IKK by wogonin led to the suppression of IκB phosphorylation and degradation, p65 nuclear translocation and NF‐κB‐regulated gene expression. This, in turn, led to the down‐regulation of MUC5AC protein production in NCI‐H292 cells. Wogonin also inhibited the gene products involved in cell survival (Bcl‐2) and proliferation (cyclooxygenase‐2). These results suggest that wogonin inhibits the NF‐κB signaling pathway, which may explain its role in the inhibition of MUC5AC mucin gene expression and production. Copyright © 2013 John Wiley & Sons, Ltd.     

Immunomodulatory Activity of the Glycoprotein Isolated from the Chinese Yam (Dioscorea opposita Thunb)

The yam (Dioscorea opposita Thunb) is a well‐known edible food and widely used as the traditional Chinese medicine. The present investigation was designed to evaluate the immunomodulatory activity of glycoprotein (DOT) from yam and explore its possible molecular mechanisms. Results showed that the DOT could improve the cell immunity, humoral immunity and phagocytic system function of the normal mice. The DOT could also increase the production of TNF‐α, interleukin‐6 and nitric oxide and enhance the pinocytosis function of macrophages. Furthermore, the DOT increased phosphor‐p38, JNK, ERK1/2 and nuclear factor kappa B (NF‐κB) p65 protein expression in peritoneal macrophages. Taken together, our data suggest that DOT could be used as a potential immunostimulant and exert its immunomodulatory activity via mitogen‐activated protein kinases and NF‐κB signal pathways. Copyright © 2017 John Wiley & Sons, Ltd.     

A Polyphenol‐rich Pomegranate Fruit Extract Suppresses NF‐κB and IL‐6 Expression by Blocking the Activation of IKKβ and NIK in Primary Human Chondrocytes

Pomegranate fruit extract (PE) rich in polyphenols has been shown to exert chondroprotective effects, but the mechanism is not established. Here, we used an in vitro model of inflammation in osteoarthritis (OA) to investigate the potential of PE to suppress interleukin 1 beta (IL‐1β)‐stimulated expression of inflammatory cytokine IL‐6, generation of reactive oxygen species (ROS) levels, and investigated the mechanism of NF‐κB inhibition by analyzing the activation of the kinases upstream of IκBα in primary human chondrocytes. Total and phosphorylated forms of kinases and expression of IL‐6 were determined at protein and mRNA levels by western immunoblotting and Taqman assay, respectively. Dihydrorhodamine 123 staining estimated ROS generation. Pomegranate fruit extract inhibited the mRNA and protein expression of IL‐6, generation of ROS, and inhibited the IL‐1β‐mediated phosphorylation of inhibitor of nuclear factor kappa‐B kinase subunit beta (IKKβ), expression of IKKβ mRNA, degradation of IκBα, and activation and nuclear translocation of NF‐κB/p65 in human chondrocytes. Importantly, phosphorylation of NF‐κB‐inducing kinase was blocked by PE in IL‐1β‐treated human OA chondrocytes. Taken together, these data suggest that PE exerts the chondroprotective effect(s) by suppressing the production of IL‐6 and ROS levels. Inhibition of NF‐κB activation by PE was blocked via modulation of activation of upstream kinases in human OA chondrocytes. Copyright © 2017 John Wiley & Sons, Ltd.     

Farrerol attenuates MPP+‐induced inflammatory response by TLR4 signaling in a microglia cell line

Farrerol was found to possess neuroprotective effect; however, the mechanism remains unknown. The aim of the present study was to explore the effect of farrerol on MPP⁺‐induced inflammation in mouse microglial BV‐2 cells and to elaborate the underlying mechanism. MTT assay was performed to measure the cell viability. The pro‐inflammatory mediators and cytokines including interleukin (IL)‐6, IL‐1β, and tumor necrosis factor‐α (TNF‐α); inducible nitric oxide synthase; and cyclooxygenase 2 were measured. The expression of p‐p65, p‐IκBα, toll‐like receptor 4 (TLR4), and myeloid differentiation primary response 88 were analyzed by western blot. We found that farrerol treatment improved cell viability in MPP⁺‐induced BV‐2 cells. MPP⁺‐induced upregulation of IL‐6, IL‐1β, and TNF‐α was inhibited by farrerol treatment. Farrerol treatment also attenuated MPP⁺‐induced expression of inducible nitric oxide synthase and cyclooxygenase 2 as well as the activation of NF‐κB in BV‐2 cells. MPP⁺‐induced TLR4 signaling was markedly diminished by farrerol treatment. Knockdown of TLR4 attenuated MPP⁺‐induced inflammatory response in BV‐2 cells. In conclusion, farrerol treatment attenuated MPP⁺‐induced inflammatory response by inhibiting the TLR4 signaling pathway in BV‐2 cells. The results indicated that farrerol could be used as a therapeutic agent for preventing or alleviating the neuroinflammation‐related diseases, such as Parkinson's disease.     

Morinda citrifolia noni water extract enhances innate and adaptive immune responses in healthy mice,ex vivo,and in vitro

Although Morinda citrifolia (noni) has long been used in traditional medicines for human diseases, its molecular and cellular mechanism of immunostimulatory ability to improve human health under normal healthy conditions is not fully elucidated. This study aimed to investigate the in vitro and in vivo immunostimulatory activity of M. citrifolia fruit water extract treated with enzymes (Mc‐eWE). In vitro studies revealed that Mc‐eWE stimulated the cells by inducing nitric oxide (NO) production and the expression of inflammatory cytokines, such as interleukin (IL)‐1β, IL‐6, IL‐12, tumor necrosis factor‐alpha (TNF‐α), and interferon‐gamma (IFN‐γ). The immunostimulatory activity was mediated by activation of NF‐κB and AP‐1. Ex vivo studies showed that Mc‐eWE stimulated splenocytes isolated from mice by inducing NO production and expression of immunostimulatory cytokines and by downregulating the expression of the immunosuppressive cytokine IL‐10 without cytotoxicity. In vivo demonstrated that Mc‐eWE induced immunostimulation by modulating populations of splenic immune cells, especially by increasing the population of IFN‐γ⁺ NK cells. Mc‐eWE enhanced the expression of inflammatory genes and immunostimulatory cytokines and inhibited the expression of IL‐10 in the mouse splenocytes and sera. Taken together, these results suggest that Mc‐eWE plays an immunostimulatory role by activating innate and adaptive immune responses.     

Casticin prevents DSS induced ulcerative colitis in mice through inhibitions of NF‐κB pathway and ROS signaling

Casticin, a compound purified from the Chinese herb Viticis Fructus, has been proven effective in preventing tumor progression in previous studies. Ulcerative colitis (UC) is a common inflammatory bowel disease that affects millions of people worldwide, but no effective and safe drugs are available. In this study, we aimed to study how did casticin affect UC by evaluating its effects on dextran sulfate sodium (DSS)‐induced colitis in mice. Our data suggested that casticin attenuated body weight loss, colon length shortening, and pathological damage in the colon of DSS‐treated mice. Casticin decreased reactive oxygen species level and chemocytokines (IL‐1β, IL‐6, TNF‐α) productions in colon tissue. The decreased reactive oxygen species level and suppressed proinflammatory cytokines productions were also confirmed in casticin‐treated LPS‐stimulated RAW264.7 cells and hydrogen peroxide‐treated CACO‐2 cells in vitro. Mechanistically, casticin treatment prevented the profound activation of AKT signaling caused by DSS administration. And casticin inhibited the productions of proinflammatory chemocytokines through downregulating AKT/NF‐κB pathway in macrophages. Meanwhile, data revealed that casticin increased expressions of endogenous antioxidants peroxiredoxin 3 and MnSOD were through activation in FOXO3α signaling by downregulating AKT signaling in colon epithelium cells. Our findings demonstrated that casticin alleviated DSS‐induced UC by increasing the antioxidant enzyme peroxiredoxin 3 and MnSOD expressions, and decreasing the production of proinflammatory chemocytokines through inhibition of AKT signaling.