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.     

Panax notoginseng saponins suppress lipopolysaccharide‐induced barrier disruption and monocyte adhesion on bEnd.3 cells via the opposite modulation of Nrf2 antioxidant and NF‐κB inflammatory pathways

Dysfunction of the blood‐brain barrier (BBB) is a prerequisite for the pathogenesis of many cerebral diseases. Oxidative stress and inflammation are well‐known factors accounting for BBB injury. Panax notoginseng saponins (PNS), a clinical commonly used drug against cerebrovascular disease, possess efficient antioxidant and anti‐inflammatory activity. In the present study, the protective effects of PNS on lipopolysaccharide (LPS)‐insulted cerebral microvascular endothelial cells (bEnd.3) were assessed and the underlying mechanisms were investigated. The results showed that PNS mitigated the decrease of Trans‐Endothelial Electrical Resistance, increase of paracellular permeability, and loss of tight junction proteins in bEnd.3 BBB model. Meanwhile, PNS suppressed the THP‐1 monocytes adhesion on bEnd.3 monolayer. Moreover, PNS prevented the pro‐inflammatory cytokines secretion and reactive oxygen species generation in bEnd.3 cells stimulated with LPS. Mechanism investigations suggested that PNS promoted the Akt phosphorylation, activated Nrf2 antioxidant signaling, and inhibited the NF‐κB activation. All the effects of PNS could be abolished by PI3K inhibition at different levels. Taken together, these observations suggest that PNS may act as an extrinsic regulator that activates Nrf2 antioxidant defense system depending on PI3K/Akt and inhibits NF‐κB inflammatory signaling to attenuate LPS‐induced BBB disruption and monocytes adhesion on cerebral endothelial cells in vitro.     

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.     

Chelidonine inhibits TNF‐α‐induced inflammation by suppressing the NF‐κB pathways in HCT116 cells

Nuclear factor kappa‐light‐chain‐enhancer of activated B cells (NF‐κB) is a complex that regulates several hundreds of genes, including those involved in immunity and inflammation, survival, proliferation, and the negative feedback of NF‐κB signaling. Chelidonine, a major bioactive, isoquinoline alkaloid ingredient in Chelidonium majus, exhibits antiinflammatory pharmacological properties. However, its antiinflammatory molecular mechanisms remain unclear. In this work, we explored the effect of chelidonine on TNF‐induced NF‐κB activation in HCT116 cells. We found chelidonine inhibited the phosphorylation and degradation of the inhibitor of NF‐κB alpha and nuclear translocation of RELA. Furthermore, by inhibiting the activation of NF‐κB, chelidonine downregulated target genes involved in inflammation, proliferation, and apoptosis. Chelidonine also inhibited mitogen‐activated protein kinase pathway activation by blocking c‐Jun N‐terminal kinase and p38 phosphorylation. These results suggest that chelidonine may be a potential therapeutic agent against inflammatory diseases in which inhibition of NF‐κB activity plays an important role.     

HIF‐1α/VEGF signaling‐mediated epithelial–mesenchymal transition and angiogenesis is critically involved in anti‐metastasis effect of luteolin in melanoma cells

Tumor metastasis is still the leading cause of melanoma mortality. Luteolin, a natural flavonoid, is found in fruits, vegetables, and medicinal herbs. The pharmacological action and mechanism of luteolin on the metastasis of melanoma remain elusive. In this study, we investigated the effect of luteolin on A375 and B16‐F10 cell viability, migration, invasion, adhesion, and tube formation of human umbilical vein endothelial cells. Epithelial–mesenchymal transition (EMT) markers and pivotal molecules in HIF‐1α/VEGF signaling expression were analysed using western blot assays or quantitative real‐time polymerase chain reaction. Results showed that luteolin inhibits cellular proliferation in A375 and B16‐F10 melanoma cells in a time‐dependent and concentration‐dependent manner. Luteolin significantly inhibited the migratory, invasive, adhesive, and tube‐forming potential of highly metastatic A375 and B16‐F10 melanoma cells or human umbilical vein endothelial cells at sub‐IC₅₀ concentrations, where no significant cytotoxicity was observed. Luteolin effectively suppressed EMT by increased E‐cadherin and decreased N‐cadherin and vimentin expression both in mRNA and protein levels. Further, luteolin exerted its anti‐metastasis activity through decreasing the p‐Akt, HIF‐1α, VEGF‐A, p‐VEGFR‐2, MMP‐2, and MMP‐9 proteins expression. Overall, our findings first time suggests that HIF‐1α/VEGF signaling‐mediated EMT and angiogenesis is critically involved in anti‐metastasis effect of luteolin as a potential therapeutic candidate for melanoma.     

Astragaloside IV Attenuates Injury Caused by Myocardial Ischemia/Reperfusion in Rats via Regulation of Toll‐Like Receptor 4/Nuclear Factor‐κB Signaling Pathway

Myocardial ischemia/reperfusion (MI/R) injury, in which inflammatory response and cell apoptosis play a vital role, is frequently encountered in clinical practice. Astragaloside IV (AsIV), a small molecular saponin of Astragalus membranaceus, has been shown to confer protective effects against many cardiovascular diseases. The present study was aimed to investigate the antiinflammatory and antiapoptotic effects and the possible mechanism of AsIV on MI/R injury in rats. Rats were randomly divided into sham operation group, MI/R group and groups with combinations of MI/R and different doses of AsIV. The results showed that the expressions of myocardial toll‐like receptor 4 (TLR4) and nuclear factor‐κB (NF‐κB) were significantly increased, and apoptosis of cardiomyocytes was induced in MI/R group compared with that in sham operation group. Administration of AsIV attenuated MI/R injury, downregulated the expressions of TLR4 and NF‐κB and inhibited cell apoptosis as evidenced by decreased terminal deoxynucleotidyl transferase dUTP nick end labeling positive cells, B‐cell lymphoma‐2 associated X protein and caspase‐3 expressions and increased B‐cell lymphoma‐2 expression compared with that in MI/R group. In addition, AsIV treatment reduced levels of inflammatory cytokines induced by MI/R injury. In conclusion, our results demonstrated that AsIV downregulates TLR4/NF‐κB signaling pathway and inhibits cell apoptosis, subsequently attenuating MI/R injury in rats. Copyright © 2015 John Wiley & Sons, Ltd.     

Nerolidol Protects Against LPS‐induced Acute Kidney Injury via Inhibiting TLR4/NF‐κB Signaling

Acute kidney injury (AKI) is a critical care syndrome, resulting in acute reduction of renal function and up to 22% mortality of hospitalized patients. Nerolidol is a major component in several essential oils that possesses various pharmacological properties. The present study aimed to investigate the potential effect of nerolidol on lipopolysaccharide (LPS)‐induced AKI. Nerolidol dose‐dependently reduced the pathological injuries of kidney induced by LPS in rats. Nerolidol significantly decreased the levels of blood urea nitrogen and creatinine in LPS‐treated rats in a dose‐dependent manner. In addition, nerolidol inhibited LPS‐induced decrease of cell viability in NRK‐52E rat proximal tubular cells, which effect was concentration dependent. Nerolidol notably inhibited the increase of TNFα and IL‐1β in LPS‐treated rats and the mRNA expression of TNFα and IL‐1β in LPS‐treated NRK‐52E cells. Nerolidol suppressed the increase of toll‐like receptor 4 (TLR4) expression, phosphorylation and nuclear translocation of p65 NF‐κB in kidneys of LPS‐treated rats and LPS‐treated NRK‐52E cells. Overexpression of TLR4 and p65 NF‐κB significantly suppressed nerolidol‐induced inhibition of TNFα and IL‐1β expression and increase of cell viability in LPS‐treated cells. In summary, we found that nerolidol played a critical anti‐inflammatory effects through inhibition of TLR4/NF‐κB signaling and protected against LPS‐induced AKI. Copyright © 2017 John Wiley & Sons, Ltd.     

1,2,3,6‐tetra‐O‐galloyl‐β‐D‐allopyranose gallotannin isolated,from Euphorbia jolkini,attenuates LPS‐induced nitric oxide production in macrophages

Nitric oxide (NO) is a pleiotropic regulator, critical to numerous biological processes, including vasodilatation and macrophage‐mediated immunity. Macrophages express inducible NO synthase (iNOS) and produce NO after lipopolysaccharide (LPS) stimulation. Gallotannins are water‐soluble polyphenols with wide‐ranging biological activities. Various chemical structures of gallotannins occurring in medicinal and food plants that are used worldwide showed several remarkable biological and pharmacological activities. In the present study, we examined the inhibitory effects of gallotannin 1,2,3,6‐tetra‐O‐galloyl‐β‐D‐allopyranose (GT24) isolated from Euphorbia jolkini on the LPS‐induced NO production and underlying mechanisms of action. GT24 dose‐dependently decreased LPS‐induced NO production and iNOS expression in J774A.1 macrophages. In addition, GT24 inhibited LPS‐induced activation of nuclear factor (NF)‐κB as indicated by inhibition of degradation of I‐κBα, nuclear translocation of NF‐κB, and NF‐κB dependent gene reporter assay. Our results suggest that GT24 possesses an inhibitory effect on the LPS‐induced inflammatory reaction. Copyright © 2010 John Wiley & Sons, Ltd.     

Apoptosis Induction by 13‐Acetoxyrolandrolide through the Mitochondrial Intrinsic Pathway

The aim of this study was to evaluate the mechanisms of cytotoxicity of the sesquiterpene lactone 13‐acetoxyrolandrolide, a nuclear factor kappa B (NF‐κB) inhibitor that was previously isolated from Rolandra fruticosa. The effects associated with the inhibition of the NF‐κB pathway included dose‐dependent inhibition of the NF‐κB subunit p65 (RelA) and inhibition of upstream mediators IKKβ and oncogenic Kirsten rat sarcoma (K‐Ras). The inhibitory concentration of 13‐acetoxyrolandrolide on K‐Ras was 7.7 µm . The downstream effects of the inhibition of NF‐κB activation were also investigated in vitro. After 24 h of treatment with 13‐acetoxyrolandrolide, the mitochondrial transmembrane potential was depolarized in human colon cancer (HT‐29) cells. The mitochondrial oxidative phosphorylation was also negatively affected, and reduced levels of nicotinamine adenine dinucleotide phosphate (NAD(P)H) were detected after 2 h of 13‐acetoxyrolandrolide exposure. Furthermore, the expression of the pro‐apoptotic protein caspase‐3 increased in a concentration‐dependent manner. Cell flow cytometry showed that 13‐acetoxyrolandrolide induced cell cycle arrest at G₁, indicating that the treated cells had undergone caspase‐3‐mediated apoptosis, indicating negative effects on cancer cell proliferation. These results suggest that 13‐acetoxyrolandrolide inhibits NF‐κB and K‐Ras and promotes cell death mediated through the mitochondrial apoptotic pathway. Copyright © 2013 John Wiley & Sons, Ltd.     

Astragaloside III activates TACE/ADAM17‐dependent anti‐inflammatory and growth factor signaling in endothelial cells in a p38‐dependent fashion

Astragaloside III (AS‐III) is a triterpenoid saponin contained in Astragali Radix and has potent anti‐inflammatory effects on vascular endothelial cells; however, underlying mechanisms are unclear. In this study, we provided the first piece of evidence that AS‐III induced phosphorylation of TNF‐α converting enzyme (TACE) at Thr735 and enhanced its sheddase activity. As a result, AS‐III reduced surface TNFR1 level and increased content of sTNFR1 in the culture media, leading to the inhibition of NF‐κB signaling pathway and attenuation of downstream cytokine gene expression. Furthermore, AS‐III induced TACE‐dependent epidermal growth factor receptor (EGFR) transactivation and activation of downstream ERK1/2 and AKT pathways. Finally, AS‐III induced activation of p38. Both TACE activation and EGFR transactivation induced by AS‐III were significantly inhibited by p38 inhibitor SB203580. Taken together, we concluded that AS‐III activates TACE‐dependent anti‐inflammatory and growth factor signaling in vascular endothelial cells in a p38‐dependent fashion, which may contribute to its cardiovascular protective effect.     

Anti‐inflammatory Effects of Ginsenosides Rg5, Rz1, and Rk1: Inhibition of TNF‐α‐induced NF‐κB,COX‐2, and iNOS transcriptional expression

In the course of this experiment on the anti‐inflammatory effect of ginsenosides, protopanaxdiol ginsenosides have shown inhibition activities in inflammatory responses: NF‐κB, COX‐2, and iNOS were induced by TNF‐α. The responses of this experiment were evaluated by NF‐κB‐luciferase assay and RT‐PCR experiment of COX‐2 and iNOS genes. The NF‐κB expressions were inhibited by ginsenosides Rd, Rg₅, Rz₁, and Rk₁ in a dose‐dependent manner. The IC₅₀ values were 3.47, 0.61, 0.63, and 0.75 μM, respectively. Particularly, ginsenosides Rg₅, Rz₁, and Rk₁ as converted ginsenosides from primary protopanaxdiol ginsenosidess significantly inhibited COX‐2 and iNOS gene expression. These inhibition levels were similar to sulfasalazine as reference material. Copyright © 2014 John Wiley & Sons, Ltd.     

Calycosin attenuates MPTP‐induced Parkinson's disease by suppressing the activation of TLR/NF‐κB and MAPK pathways

Parkinson is the second common neurodegenerative disease. The characteristics of Parkinson's disease (PD) are the dopamin neurons loss caused by neuroinflammation responses. C alycosin, an isoflavone phytoestrogen isolated from Astragalus membranaceus, has multiple pharmacological activities, such as anti‐inflammation, anti‐tumor, and neuroprotective effects. However, it is unknown whether calycosin can mitigate PD symptoms. This study aims to explore whether calycosin can alleviate PD symptoms and the underlying mechanisms. PD was induced in mice by 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP) injection, and calycosin was given intracerebroventricularly to these mice. A cell model of nerve inflammation was established by BV2 microglia cells injected with lipopolysaccharide (LPS). The motor states were evaluated by stepping, whisker, and cylinder experiments. The states of dopaminergic neurons and microglia were detected by immunostainning of tyrosine hydroxylase and cluster of differentiation molecule 11b (CD11b). The expression levels of inflammatory factors were detected by qPCR. Toll‐like receptor (TLR)/nuclear factor kappa B (NF‐κB) and mitogen‐activated protein kinase (MAPK) pathways were investigated by western blot. We found that calycosin treatment mitigated the behavioral dysfunctions and inflammatory responses in MPTP‐induced PD mice. The TLR/NF‐κB and MAPK pathways in MPTP‐induced PD mice were inhibited by calycosin treatment, which was coincident with experiments in LPS‐induced BV2 cells. Above all, calycosin mitigates PD symptoms through TLR/NF‐κB and MAPK pathways in mice and cell lines.     

5,7‐Dihydroxy‐6‐Methoxy‐Flavonoids Eliminate HIV‐1 D3‐transfected Cytoprotective Macrophages by Inhibiting the PI3K/Akt Signaling Pathway

Flavonoids, well‐documented secondary metabolites in many vegetables and plants, exhibit antiinflammatory, anti‐oxidant, anti‐microbial, and anticancer activities. However, their cytotoxic effects against human immunodeficiency virus type 1 (HIV‐1)‐infected cytoprotective macrophages have not been studied. In the present study, we investigated their effects and their molecular mechanisms. Treatment with flavonoids in the presence of lipopolysaccharide (LPS)/cycloheximide (CHX) potently eliminated HIV‐1 Tat‐transduced cytoprotective human microglial CHME5 cells; the 5,7‐dihydroxy‐6‐methoxy‐flavonoids oroxylin A and tectorigenin, at a concentration of 10 μM, most potently eliminated the cytoprotective phenotype. These flavonoids eliminated Tat‐transduced CHME5 cells, D3‐transfected CHME5 cells, and HIV‐1 D3‐infected human primary macrophages, in a dose‐dependent manner. Furthermore, oroxylin A and tectorigenin potently inhibited LPS/CHX‐induced phosphorylation of phosphoinositide 3‐kinase (PI3K), pyruvate dehydrogenase lipoamide kinase isozyme 1, Akt, and glycogen synthase kinase‐3β in the Tat‐transduced cells, D3‐transfected CHME5 cells, and D3‐infected human primary macrophages. Based on these findings, 5,7‐dihydroxy‐6‐methoxy‐flavonoids may eliminate HIV‐1 infected cytoprotective macrophages by inhibiting the PI3K/Akt signaling pathway and deliver anti‐HIV‐1 effects in vivo by shortening the lifespan of infected macrophages. Copyright © 2015 John Wiley & Sons, Ltd.     

Theacrine attenuates epithelial mesenchymal transition in human breast cancer MDA‐MB‐231 cells

Theacrine, a purine alkaloid structurally similar to caffeine, has recently become of interest as a potential therapeutic compound. Here, we investigated the antimetastatic potential of theacrine on human breast cancer MDA‐MB‐231 cells. We observed that theacrine can reverse epithelial‐to‐mesenchymal transition (EMT), which resulted in a decrease in the levels of mesenchymal markers (Fibronectin, Vimentin, N‐cadherin, Twist, and Snail) and an increase in the levels of epithelial markers (Occludin and E‐cadherin) in the cells. Additionally, theacrine attenuates TGF‐β‐induced EMT, cell adhesion, migration, and invasion in MDA‐MB‐231 cells. Overall, our results suggest that theacrine may inhibit the breast cancer cell metastasis by reversing the EMT process.     

Apoptotic Effect of Sanggenol L via Caspase Activation and Inhibition of NF‐κB Signaling in Ovarian Cancer Cells

In the present study, the underlying apoptotic mechanism of sanggenol L was elucidated in ovarian cancer cells. Sanggenol L showed cytotoxic and antiproliferative effect in A2780, SKOV‐3, and OVCAR‐3 ovarian cancer cells in a concentration‐dependent fashion. Consistently, sanggenol L increased sub‐G1 phase population and early and late apoptotic portion in ovarian cancer cells. Also, sanggenol L activated caspase9/3, suppressed the phosphorylation of IκBα and p65 NF‐κB (nuclear factor kappa‐light‐chain‐enhancer of activated B cells), attenuated the expression of Cyclin D1, and cleaved poly(adenosine diphosphate ribose ‐ribose) polymerase in SKOV‐3, A2780, and OVCAR‐3 cells. Furthermore, sanggenol L blocked nuclear translocation of NF‐κB and also attenuated the expression of NF‐κB related genes such as c‐Myc, Cyclin D1, and Bcl‐_XL, Bcl‐2, in lipopolysaccharide‐treated SKOV‐3 cells. Overall, our findings for the first time suggest that sanggenol L induces apoptosis via caspase activation and inhibition of NF‐κB/IκBα phosphorylation as a potent chemotherapeutic agent for ovarian cancers. Copyright © 2015 John Wiley & Sons, Ltd.