Naringin Attenuates the Development of Carrageenan-Induced Acute Lung Inflammation Through Inhibition of NF-κb, STAT3 and Pro-Inflammatory Mediators and Enhancement of IκBα and Anti-Inflammatory Cytokines

The role of select pro- and anti-inflammatory mediators in driving microglial cell polarization into classically (M1), or alternatively, (M2) activated states, as well as the subsequent differential responses of these induced phenotypes, was examined. Expression of PD-L1, MHC-II, MHC-I, arginase 1 (Arg-1), and inducible nitric oxide synthase (iNOS) was assessed using multi-color flow cytometry. We observed that both pro- and anti-inflammatory mediators induced PD-L1 expression on non-polarized microglia. Moreover, IFN-γ stimulated significant MHC class I and II expression on these cells. Interestingly, we observed that only IL-4 treatment induced Arg-1 expression, indicating M2 polarization. These M2 cells were refractory to subsequent depolarization and maintained their alternatively activated state. Furthermore, PD-L1 expression was significantly induced on these M2-polarized microglia after treatment with pro-inflammatory mediators, but not anti-inflammatory cytokines. In addition, we observed that only LPS induced iNOS expression in microglial cells, indicating M1 polarization. Furthermore, IFN-γ significantly increased the percentage of M1-polarized microglia expressing iNOS. Surprisingly, when these M1-polarized microglia were treated with either IL-6 or other anti-inflammatory cytokines, they returned to their non-polarized state, as demonstrated by significantly reduced expression of iNOS. Taken together, these results demonstrate differential responses of microglial cells to mediators present in dissimilar microenvironments.

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The Crucial Role of PPARγ-Egr-1-Pro-Inflammatory Mediators Axis in IgG Immune Complex-Induced Acute Lung Injury

Frontiers in Immunology ◽

10.3389/fimmu.2021.634889 ◽

2021 ◽

Vol 12 ◽

Author(s):

Chunguang Yan ◽

Jing Chen ◽

Yue Ding ◽

Zetian Zhou ◽

Bingyu Li ◽

...

Keyword(s):

Transcription Factor ◽

Acute Lung Injury ◽

Lung Injury ◽

Immune Complex ◽

Inflammatory Mediators ◽

Lung Inflammation ◽

Acute Lung Inflammation ◽

Pparγ Agonist

BackgroundThe ligand-activated transcription factor peroxisome proliferator-activated receptor (PPAR) γ plays crucial roles in diverse biological processes including cellular metabolism, differentiation, development, and immune response. However, during IgG immune complex (IgG-IC)-induced acute lung inflammation, its expression and function in the pulmonary tissue remains unknown.ObjectivesThe study is designed to determine the effect of PPARγ on IgG-IC-triggered acute lung inflammation, and the underlying mechanisms, which might provide theoretical basis for therapy of acute lung inflammation.SettingDepartment of Pathogenic Biology and Immunology, Medical School of Southeast UniversitySubjectsMice with down-regulated/up-regulated PPARγ activity or down-regulation of Early growth response protein 1 (Egr-1) expression, and the corresponding controls.InterventionsAcute lung inflammation is induced in the mice by airway deposition of IgG-IC. Activation of PPARγ is achieved by using its agonist Rosiglitazone or adenoviral vectors that could mediate overexpression of PPARγ. PPARγ activity is suppressed by application of its antagonist GW9662 or shRNA. Egr-1 expression is down-regulated by using the gene specific shRNA.Measures and Main ResultsWe find that during IgG-IC-induced acute lung inflammation, PPARγ expression at both RNA and protein levels is repressed, which is consistent with the results obtained from macrophages treated with IgG-IC. Furthermore, both in vivo and in vitro data show that PPARγ activation reduces IgG-IC-mediated pro-inflammatory mediators’ production, thereby alleviating lung injury. In terms of mechanism, we observe that the generation of Egr-1 elicited by IgG-IC is inhibited by PPARγ. As an important transcription factor, Egr-1 transcription is substantially increased by IgG-IC in both in vivo and in vitro studies, leading to augmented protein expression, thus amplifying IgG-IC-triggered expressions of inflammatory factors via association with their promoters.ConclusionDuring IgG-IC-stimulated acute lung inflammation, PPARγ activation can relieve the inflammatory response by suppressing the expression of its downstream target Egr-1 that directly binds to the promoter regions of several inflammation-associated genes. Therefore, regulation of PPARγ-Egr-1-pro-inflammatory mediators axis by PPARγ agonist Rosiglitazone may represent a novel strategy for blockade of acute lung injury.

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Anti-Inflammatory Effect of Lycii radicis in LPS-Stimulated RAW 264.7 Macrophages

The American Journal of Chinese Medicine ◽

10.1142/s0192415x14500566 ◽

2014 ◽

Vol 42 (04) ◽

pp. 891-904 ◽

Cited By ~ 11

Author(s):

Mi Young Song ◽

Hyo Won Jung ◽

Seok Yong Kang ◽

Kyung-Ho Kim ◽

Yong-Ki Park

Keyword(s):

Inflammatory Cytokines ◽

Inflammatory Mediators ◽

Water Extract ◽

Inhibitory Effect ◽

Raw 264.7 Cells ◽

Raw 264.7 ◽

Root Bark ◽

Lycium Barbarum ◽

Anti Inflammatory ◽

Inflammatory Effect

The root bark of Lycium barbarum (Lycii radicis cortex, LRC) is used as a cooling agent for fever and night sweats in East Asian traditional medicine. The inhibitory effect of LRC water extract on inflammation is unknown. In this study, the anti-inflammatory effect of LRC was investigated in lipopolysaccharide (LPS)-stimulated mouse macrophage, RAW 264.7 cells. LRC extract significantly decreased the LPS-induced production of inflammatory mediators, nitric oxide (NO), prostaglandin (PG) E2 and pro-inflammatory cytokines, interleukin (IL)-1β and IL-6 in the cells. In addition, LRC extract inhibited the LPS-induced expression of inducible NO synthase (iNOS) and cyclooxygenase (COX)-2 mRNA and protein, and inflammatory cytokines mRNA in the cells. The action mechanism of LRC underlies the blocking of LPS-mediated p38 and Jun N-terminal kinase (JNK), mitogen-activated protein kinases (MAPKs), and the nuclear factor (NF)-κB signaling pathway. These results indicate that LRC extract inhibits the inflammatory response in activated macrophages by down-regulating the transcription levels of inflammatory mediators and blocking the MAPKs and NF-κB pathway.

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The Interplay of Pro-Inflammatory Cytokines and Anti-Inflammatory Mediators during Severe Infection

Yearbook of Intensive Care and Emergency Medicine ◽

10.1007/978-3-642-79154-3_30 ◽

1995 ◽

pp. 377-384 ◽

Cited By ~ 1

Author(s):

J. W. M. van der Meer ◽

M. van Deuren ◽

B. J. Kullberg

Keyword(s):

Inflammatory Cytokines ◽

Inflammatory Mediators ◽

Severe Infection ◽

Anti Inflammatory ◽

Pro Inflammatory Cytokines

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Astilbe Chinensis ethanol extract suppresses inflammation in macrophages via NF-κB pathway

BMC Complementary Medicine and Therapies ◽

10.1186/s12906-020-03073-5 ◽

2020 ◽

Vol 20 (1) ◽

Cited By ~ 1

Author(s):

Tae-Young Gil ◽

Bo-Ram Jin ◽

Chul-Hee Hong ◽

Jong Hyuk Park ◽

Hyo-Jin An

Keyword(s):

Nitric Oxide ◽

Inflammatory Cytokines ◽

Inflammatory Mediators ◽

Ethanol Extract ◽

Nuclear Factor Κb ◽

Peritoneal Macrophages ◽

Necrosis Factor Alpha ◽

Iκb Kinase ◽

Anti Inflammatory ◽

Pro Inflammatory Cytokines

Abstract Background Macrophages play a crucial role in inflammation. Astilbe chinensis is one of perennial herbs belonging to the genus Astilbe. Plants in the genus have been used for pain, headaches, arthralgia, and chronic bronchitis. However, the effect of A.chinensis on inflammation remains unclear. To study the anti-inflammatory action of A.chinensis ethanol extract (ACE), we investigated the effect of ACE on the production of pro-inflammatory mediators and cytokines in macrophages. Methods We evaluated the effectiveness of ACE in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages and thioglycollate (TG)-elicited peritoneal macrophages from male C57BL/6 mice. We measured the levels of pro-inflammatory mediators and cytokines, and examined the anti-inflammatory actions of ACE on nuclear factor κB (NF-κB) pathway in the macrophages. Western blot analysis and immunofluorescence microscopy were used to determine protein level and translocation, respectively. Results ACE suppressed the output of nitric oxide (NO), prostaglandin E2 (PGE2), and pro-inflammatory cytokines in stimulated macrophages via inhibiting the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins. ACE suppressed mRNA expression of pro-inflammatory cytokines such as interleukin (IL)-6 and tumor necrosis factor-alpha (TNF-α). We examined the efficacies of ACE on NF-κB activation by measuring the expressions including IκB kinase (IKK), inhibitor of κB (IκB), and nuclear p65 proteins. In addition, the inhibition of NF-κB p65’s translocation was determined with immunofluorescence assay. Conclusion Our findings manifested that ACE inhibited LPS or TG-induced inflammation by blocking the NF-κB signaling pathway in macrophages. It indicated that ACE is a potential therapeutic mean for inflammation and related diseases.

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Pro-inflammatory cytokines reduce human TAFI expression via tristetraprolin-mediated mRNA destabilisation and decreased binding of HuR

Thrombosis and Haemostasis ◽

10.1160/th14-08-0653 ◽

2015 ◽

Vol 114 (08) ◽

pp. 337-349 ◽

Cited By ~ 7

Author(s):

Dragana Komnenov ◽

Corey Scipione ◽

Zainab Bazzi ◽

Justin Garabon ◽

Marlys Koschinsky ◽

...

Keyword(s):

Inflammatory Cytokines ◽

Inflammatory Mediators ◽

Hepg2 Cells ◽

Inflammatory Cells ◽

Gene Encoding ◽

Protein Levels ◽

Anti Inflammatory ◽

Mechanistic Basis ◽

Pro Inflammatory Cytokines

SummaryThrombin activatable fibrinolysis inhibitor (TAFI) is the zymogen form of a basic carboxypeptidase (TAFIa) with both anti-fibrinolytic and anti-inflammatory properties. The role of TAFI in inflammatory disease is multifaceted and involves modulation both of specific inflammatory mediators as well as of the behaviour of inflammatory cells. Moreover, as suggested by in vitro studies, inflammatory mediators are capable of regulating the expression of CPB2, the gene encoding TAFI. In this study we addressed the hypothesis that decreased TAFI levels observed in inflammation are due to post-transcriptional mechanisms. Treatment of human HepG2 cells with pro-inflammatory cytokines TNFα, IL-6 in combination with IL-1β, or with bacterial lipopolysaccharide (LPS) decreased TAFI protein levels by approximately two-fold over 24 to 48 hours of treatment. Conversely, treatment of HepG2 cells with the anti-inflammatory cytokine IL-10 increased TAFI protein levels by two-fold at both time points. We found that the mechanistic basis for this modulation of TAFI levels involves binding of tristetraprolin (TTP) to the CPB2 3′-UTR, which mediates CPB2 mRNA destabilisation. In this report we also identified that HuR, another ARE-binding protein but one that stabilises transcripts, is capable of binding the CBP2 3’UTR. We found that pro-inflammatory mediators reduce the occupancy of HuR on the CPB2 3’-UTR and that the mutation of the TTP binding site in this context abolishes this effect, although TTP and HuR appear to contact discrete binding sites. Interestingly, all of the mediators tested appear to increase TAFI protein expression in THP-1 macrophages, likewise through effects on CPB2 mRNA stability.

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