Glycyrrhizin, the main active compound in liquorice, attenuates pro-inflammatory responses by interfering with membrane-dependent receptor signalling

2009 ◽  
Vol 421 (3) ◽  
pp. 473-482 ◽  
Author(s):  
Bärbel Schröfelbauer ◽  
Johanna Raffetseder ◽  
Maria Hauner ◽  
Andrea Wolkerstorfer ◽  
Wolfgang Ernst ◽  
...  

The triterpene glycoside glycyrrhizin is the main active compound in liquorice. It is used as a herbal medicine owing to its anticancer, antiviral and anti-inflammatory properties. Its mode of action, however, remains widely unknown. In the present study, we aimed to elucidate the molecular mechanism of glycyrrhizin in attenuating inflammatory responses in macrophages. Using microarray analysis, we found that glycyrrhizin caused a broad block in the induction of pro-inflammatory mediators induced by the TLR (Toll-like receptor) 9 agonist CpG-DNA in RAW 264.7 cells. Furthermore, we found that glycyrrhizin also strongly attenuated inflammatory responses induced by TLR3 and TLR4 ligands. The inhibition was accompanied by decreased activation not only of the NF-κB (nuclear factor κB) pathway but also of the parallel MAPK (mitogen-activated protein kinase) signalling cascade upon stimulation with TLR9 and TLR4 agonists. Further analysis of upstream events revealed that glycyrrhizin treatment decreased cellular attachment and/or uptake of CpG-DNA and strongly impaired TLR4 internalization. Moreover, we found that the anti-inflammatory effects were specific for membrane-dependent receptor-mediated stimuli, as glycyrrhizin was ineffective in blocking Tnfa (tumour necrosis factor α gene) induction upon stimulation with PMA, a receptor- and membrane-independent stimulus. These observations suggest that the broad anti-inflammatory activity of glycyrrhizin is mediated by the interaction with the lipid bilayer, thereby attenuating receptor-mediated signalling.

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7393
Author(s):  
Jung-Hwan Kim ◽  
Tae-Jin Park ◽  
Jin-Soo Park ◽  
Min-Seon Kim ◽  
Won-Jae Chi ◽  
...  

Luteolin (LT), present in most plants, has potent anti-inflammatory properties both in vitro and in vivo. Furthermore, some of its derivatives, such as luteolin-7-O-glucoside, also exhibit anti-inflammatory activity. However, the molecular mechanisms underlying luteolin-3′-O-phosphate (LTP)-mediated immune regulation are not fully understood. In this paper, we compared the anti-inflammatory properties of LT and LTP and analyzed their molecular mechanisms of action; we obtained LTP via the biorenovation of LT. We investigated the anti-inflammatory activities of LT and LTP in macrophage RAW 264.7 cells. We confirmed from previously reported literature that LT inhibits the production of nitric oxide and prostaglandin E2, as well as the expression of inducible NO synthetase and cyclooxygenase-2. In addition, expressions of inflammatory genes and mediators, such as tumor necrosis factor-α, interleukin-6, and interleukin-1β, were suppressed. LTP showed anti-inflammatory activity similar to LT, but better anti-inflammatory activity in all the experiments, while also inhibiting mitogen-activated protein kinase and nuclear factor-kappa B more effectively than LT. At a concentration of 10 μM, LTP showed differences of 2.1 to 44.5% in the activity compared to LT; it also showed higher anti-inflammatory activity. Our findings suggest that LTP has stronger anti-inflammatory activity than LT.


Author(s):  
Hanna Galganska ◽  
Wieslawa Jarmuszkiewicz ◽  
Lukasz Galganski

AbstractMitogen-activated protein kinase (MAPK) signalling pathways are crucial for developmental processes, oncogenesis, and inflammation, including the production of proinflammatory cytokines caused by reactive oxygen species and upon severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. There are no drugs that can effectively prevent excessive inflammatory responses in endothelial cells in the lungs, heart, brain, and kidneys, which are considered the main causes of severe coronavirus disease 2019 (COVID-19). In this work, we demonstrate that human MAPKs, i.e. extracellular signal-regulated kinases 1 and 2 (ERK1/2), are CO2 sensors and CO2 is an efficient anti-inflammatory compound that exerts its effects through inactivating ERK1/2 in cultured endothelial cells when the CO2 concentration is elevated. CO2 is a potent inhibitor of cellular proinflammatory responses caused by H2O2 or the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2. ERK1/2 activated by the combined action of RBD and cytokines crucial for the development of severe COVID-19, i.e. interferon-gamma (IFNγ) and tumour necrosis factor-α (TNFα), are more effectively inactivated by CO2 than by dexamethasone or acetylsalicylic acid in human bronchial epithelial cells. Previously, many preclinical and clinical studies showed that the transient application of 5–8% CO2 is safe and effective in the treatment of many diseases. Therefore, our research indicates that CO2 may be used for the treatment of COVID-19 as well as the modification of hundreds of cellular pathways.


2013 ◽  
Vol 91 (2) ◽  
pp. 141-148 ◽  
Author(s):  
Ji-Youn Lim ◽  
Donggeun Sul ◽  
Bang Yeon Hwang ◽  
Kwang Woo Hwang ◽  
Ki-Yeol Yoo ◽  
...  

Microglia are a type of resident macrophage that functions as an inflammation modulator in the central nervous system. Over-activation of microglia by a range of stimuli disrupts the physiological homeostasis of the brain, and induces inflammatory response and degenerative processes, such as those implicated in neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease. Therefore, we investigated the possible anti-inflammatory mechanisms of inflexanin B in murine microglial BV2 cells. Lipopolysaccharide (LPS) activated BV2 cells and induced the production of pro-inflammatory mediators such as nitric oxide (NO), prostaglandin E2 (PGE2), and cytokines (interleukins-1β and -6, and tumour necrosis factor α). The LPS-induced production of pro-inflammatory mediators was associated with the enhancement of nuclear factor-kappaB (NF-κB) nuclear translocation and the activation of mitogen-activated protein kinase (MAPK) including ERK1/2 and JNK. Conversely, pretreatment of cells with inflexanin B (10 and 20 μg/mL) significantly reduced the production of pro-inflammatory mediators. This was accompanied with the reduced nuclear translocation of NF-κB and reduced activation of MAPKs. These results suggest that inflexanin B attenuated the LPS-induced inflammatory process by inhibiting the activation of NF-κB and MAPKs.


2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Miki Torigoe ◽  
Yoko Obata ◽  
Hiro Inoue ◽  
Kenta Torigoe ◽  
Akira Kinoshita ◽  
...  

Abstract Background and Aims Anti-glomerular basement membrane (GBM) glomerulonephritis (GN), characterized by glomerular crescent formation, requires early treatment because of poor prognosis. Hydroxychloroquine (HCQ) is a well-known antimalarial drug. In addition, it has immunomodulatory, anti-inflammatory, and autophagy inhibitory effects and its recognized in the treatment of autoimmune disease such as SLE. However, its effect for anti-GBM GN is unknown. In this study, we investigated the effect of HCQ against anti-GBM GN in rats. Method 7 week old male, WKY rats were induced by the administration of anti-GBM serum (50μg/rat). We administered either HCQ (50mg/kg) or vehicle (Phosphate-buffered saline) from day 0 to day 7 after the induction of nephritis. Renal function was assessed by measuring serum creatinine, proteinuria, hematuria. Urine was collected for 24 hours on day 1, 3, 5, and 7. Rats were sacrificed on day 7 after induction of anti-GBM GN. Renal histological changes were assessed by PAS staining, and Masson trichrome stain, and macrophage was assessed by ED-1 stain. Mitogen-Activated Protein Kinase (MAPK) was evaluated by western blotting (WB) and inflammatory cytokines were evaluated by ELISA using urine. Results HCQ treatment suppressed renal function decline. Histologically, extracellular and intracellular cells were increased from day 1, fibrinoid necrosis and ED-1 positive cells were observed from day 3. Rats with anti-GBM GN had high levels of interferon-α, interleukin-6, monocyte chemotactic protein-1, and tumor necrosis factor-α. These changes were significantly suppressed by HCQ. In addition, HCQ suppressed phosphorylation of JNK/p38 MAPK. Conclusion Our study showed that HCQ could attenuate anti-GBM GN and have an anti-inflammatory effect by inhibiting JNK/p38 MAPK activation. HCQ may have therapeutic potential in anti-GBM GN.


2007 ◽  
Vol 204 (3) ◽  
pp. 583-594 ◽  
Author(s):  
Chul-Su Yang ◽  
Dong-Seok Lee ◽  
Chang-Hwa Song ◽  
Se-Jin An ◽  
Shengjin Li ◽  
...  

Mammalian 2-Cys peroxiredoxin II (Prx II) is a cellular peroxidase that eliminates endogenous H2O2. The involvement of Prx II in the regulation of lipopolysaccharide (LPS) signaling is poorly understood. In this report, we show that LPS induces substantially enhanced inflammatory events, which include the signaling molecules nuclear factor κB and mitogen-activated protein kinase (MAPK), in Prx II–deficient macrophages. This effect of LPS was mediated by the robust up-regulation of the reactive oxygen species (ROS)–generating nicotinamide adenine dinucleotide phosphate (NADPH) oxidases and the phosphorylation of p47phox. Furthermore, challenge with LPS induced greater sensitivity to LPS-induced lethal shock in Prx II–deficient mice than in wild-type mice. Intravenous injection of Prx II–deficient mice with the adenovirus-encoding Prx II gene significantly rescued mice from LPS-induced lethal shock as compared with the injection of a control virus. The administration of catalase mimicked the reversal effects of Prx II on LPS-induced inflammatory responses in Prx II–deficient cells, which suggests that intracellular H2O2 is attributable, at least in part, to the enhanced sensitivity to LPS. These results indicate that Prx II is an essential negative regulator of LPS-induced inflammatory signaling through modulation of ROS synthesis via NADPH oxidase activities and, therefore, is crucial for the prevention of excessive host responses to microbial products.


Blood ◽  
2011 ◽  
Vol 117 (13) ◽  
pp. 3569-3574 ◽  
Author(s):  
Grethe Kock ◽  
Anita Bringmann ◽  
Stefanie Andrea Erika Held ◽  
Solveig Daecke ◽  
Annkristin Heine ◽  
...  

Abstract Dectin-1 is the major receptor for fungal β-glucans. The activation of Dectin-1 leads to the up-regulation of surface molecules on dendritic cells (DCs) and cytokine secretion. Furthermore, Dectin-1 is important for the recruitment of leukocytes and the production of inflammatory mediators. Peroxisome proliferator–activated receptor-γ (PPAR-γ) and its ligands, cyclopentenone prostaglandins or thiazolidinediones, have modulatory effects on B-cell, T-cell, and DC function. In the present study, we analyzed the effects of troglitazone (TGZ), a high-affinity synthetic PPAR-γ ligand, on the Dectin-1–mediated activation of monocyte-derived human DCs. Dectin-1–mediated activation of DCs was inhibited by TGZ, as shown by down-regulation of costimulatory molecules and reduced secretion of cytokines and chemokines involved in T-lymphocyte activation. Furthermore, TGZ inhibited the T-cell–stimulatory capacity of DCs. These effects were not due to a diminished expression of Dectin-1 or to a reduced phosphorylation of spleen tyrosine kinase; they were mediated by the inhibition of downstream signaling molecules such as mitogen-activated protein kinases and nuclear factor-κB. Furthermore, curdlan-mediated accumulation of caspase recruitment domain 9 (CARD9) in the cytosol was inhibited by TGZ. Our data demonstrate that the PPAR-γ ligand TGZ inhibits Dectin-1–mediated activation by interfering with CARD9, mitogen-activated protein kinase, and nuclear factor-κB signaling pathways. This confirms their important role as negative-feedback regulators of potentially harmful inflammatory responses.


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