Hypoxia enhances lysosomal TNF-α degradation in mouse peritoneal macrophages

2008 ◽  
Vol 295 (1) ◽  
pp. C2-C12 ◽  
Author(s):  
Nitza Lahat ◽  
Michal A. Rahat ◽  
Amalia Kinarty ◽  
Lea Weiss-Cerem ◽  
Sigalit Pinchevski ◽  
...  

Infection, simulated by lipopolysaccharide (LPS), is a potent stimulator of tumor necrosis factor-α (TNF-α) production, and hypoxia often synergizes with LPS to induce higher levels of the secreted cytokine. However, we show that in primary mouse peritoneal macrophages and in three mouse peritoneal macrophage cell lines (RAW 264.7, J774A.1, and PMJ-2R), hypoxia (O2 < 0.3%) reduces the secretion of LPS-induced TNF-α ( P < 0.01). In RAW 264.7 cells this reduction was not regulated transcriptionally as TNF-α mRNA levels remained unchanged. Rather, hypoxia and LPS reduced the intracellular levels of TNF-α by twofold ( P < 0.01) by enhancing its degradation in the lysosomes and inhibiting its secretion via secretory lysosomes, as shown by confocal microscopy and verified by the use of the lysosome inhibitor Bafilomycin A1. In addition, although hypoxia did not change the accumulation of the soluble receptor TNF-RII, it increased its binding to the secreted TNF-α by twofold ( P < 0.05). We suggest that these two posttranslational regulatory checkpoints coexist in hypoxia and may partially explain the reduced secretion and diminished biological activity of TNF-α in hypoxic peritoneal macrophages.

2008 ◽  
Vol 86 (10) ◽  
pp. 682-690 ◽  
Author(s):  
Hyo-Jin An ◽  
Hong-Kun Rim ◽  
Jong-Hyun Lee ◽  
Se-Eun Suh ◽  
Ji-Hyun Lee ◽  
...  

Using mouse peritoneal macrophages, we have examined the mechanism by which Leonurus sibiricus (LS) regulates nitric oxide (NO) production. When LS was used in combination with recombinant interferon-γ (rIFN-γ), there was a marked cooperative induction of NO production; however, LS by itself had no effect on NO production. The increased production of NO from rIFN-γ plus LS-stimulated cells was almost completely inhibited by pretreatment with pyrrolidine dithiocarbamate (PDTC), an inhibitor of nuclear factor κB. Furthermore, treatment of peritoneal macrophages with rIFN-γ plus LS caused a significant increase in tumor necrosis factor-α (TNF-α) production. PDTC also decreased the effect of LS on TNF-α production significantly. Because NO and TNF-α play an important role in immune function and host defense, LS treatment could modulate several aspects of host defense mechanisms as a result of stimulation of the inducible nitric oxide synthase.


2011 ◽  
Vol 39 (06) ◽  
pp. 1261-1273 ◽  
Author(s):  
Hee Kang ◽  
Ha-Deok Jeong ◽  
Ho-Young Choi

Solanum nigrum L., commonly known as black nightshade, is used worldwide for the treatment of skin and mucosal ulcers, liver cirrhosis and edema. We aimed to determine the anti-inflammatory active fraction of S. nigrum by serial extractions. S. nigrum was first extracted with methanol, then fractionated with chloroform and water. The effects of S. nigrum fractions, diosgenin and α-solanine on LPS/interferon-gamma-induced nitric oxide (NO) and inducible NO synthase (iNOS), or LPS-induced tumor necrosis factor-α (TNF-α) and interleukin (IL)-6, in mouse peritoneal macrophages were determined. Western blotting analysis was used to detect LPS-induced phosphorylation of p38, JNK and ERK1/2. The chloroform fraction of S. nigrum was cytotoxic in a time and concentration dependent manner; however, the methanol and water fractions were not. The chloroform fraction reduced NO through inhibition of iNOS synthesis and inhibited TNF-α and IL-6 at the level of protein secretion; the methanol and water fractions showed a weak or no effect. The chloroform fraction also suppressed p38, JNK and ERK1/2. Diosgenin and α-solanine were cytotoxic at a high concentration. In particular, diosgenin was able to inhibit TNF-α and IL-6, but both compounds did not affect LPS-induced iNOS expression. These results indicate that the anti-inflammatory compounds of S. nigrum exist preferentially in the nonpolar fraction, ruling out the possibility that diosgenin and α-solanine are the likely candidates. The inhibition of iNOS, TNF-α and IL-6 by the chloroform fraction may be partly due to the suppression of p38, JNK and ERK1/2. Further study is required to identify the active compounds of S. nigrum.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Haidy A. Saleh ◽  
Eman Ramdan ◽  
Mohey M. Elmazar ◽  
Hassan M. E. Azzazy ◽  
Anwar Abdelnaser

AbstractDoxorubicin (DOX) chemotherapy is associated with the release of inflammatory cytokines from macrophages. This has been suggested to be, in part, due to DOX-mediated leakage of endotoxins from gut microflora, which activate Toll-like receptor 4 (TLR4) signaling in macrophages, causing severe inflammation. However, the direct function of DOX on macrophages is still unknown. In the present study, we tested the hypothesis that DOX alone is incapable of stimulating inflammatory response in macrophages. Then, we compared the anti-inflammatory effects of curcumin (CUR), resveratrol (RES) and sulforaphane (SFN) against lipopolysaccharide/interferon-gamma (LPS/IFN-γ)-mediated inflammation in the absence or presence of DOX. For this purpose, RAW 264.7 cells were stimulated with LPS/IFN-γ (10 ng/mL/10 U/mL) in the absence or presence of DOX (0.1 µM). Our results showed that DOX alone is incapable of stimulating an inflammatory response in RAW 264.7 macrophages. Furthermore, after 24 h of incubation with LPS/IFN-γ, a significant increase in tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and inducible nitric oxide synthase (iNOS) mRNA levels was observed. Similarly, nitric oxide (NO) production and TNF-α and IL-6 protein levels were significantly upregulated. Moreover, in LPS/IFN-γ-treated macrophages, the microRNAs (miRNAs) miR-146a, miR-155, and miR-21 were significantly overexpressed. Interestingly, upon testing CUR, RES, and SFN against LPS/IFN-γ-mediated inflammation, only SFN was able to significantly reverse the LPS/IFN-γ-mediated induction of iNOS, TNF-α and IL-6 and attenuate miR-146a and miR-155 levels. In conclusion, SFN, at the transcriptional and posttranscriptional levels, exhibits potent immunomodulatory action against LPS/IFN-γ-stimulated macrophages, which may indicate SFN as a potential treatment for DOX-associated inflammation.


2017 ◽  
Vol 42 (6) ◽  
pp. 2559-2568 ◽  
Author(s):  
Ping Chang ◽  
Juan Liu ◽  
Ying Yu ◽  
Shao-Ye Cui ◽  
Zhen-Hui Guo ◽  
...  

Background/Aims: This study investigated signaling pathways via which extracellular histones induce the pro-inflammatory cytokine tumor necrosis factor-α (TNF-α) release from the macrophage cell line RAW 264.7 and the anti-inflammatory efficacy of the antioxidant alpha-lipoic acid (ALA). Methods: ELISA and western blotting analyses were conducted to detect the release of TNF-α from histone-stimulated RAW 264.7 macrophages and the associated phospho-activation of MAPKs (ERK and p38) and NF-κB p65. The effects of ALA on the release of TNF-α and phospho-activation of the MAPKs and NF-κB p65 were studied. P < 0.05 was considered statistically significant. Results: Extracellular histones dose-dependently induced TNF-α release from RAW 264.7 cells and increased the phosphorylation of p38, ERK, and NF-κB p65. TNF-α release was markedly suppressed by p38, ERK, and NF-kB inhibitors. ALA reduced histone-induced TNF-α release, ERK/p38 MAPK activation, and NF-kB activation without affecting macrophage viability. Conclusion: Histones induce TNF-α release from macrophages by activating the MAPK and NF-kB signaling pathways, while ALA suppresses this response by inhibiting ERK, p38 and NF-kB. These findings identify potentially critical inflammatory signaling pathways in sepsis and molecular targets for sepsis treatment.


1998 ◽  
Vol 275 (1) ◽  
pp. G39-G46 ◽  
Author(s):  
Steven N. Lichtman ◽  
Jian Wang ◽  
John J. Lemasters

Lipopolysaccharide (LPS) is a bacterial polymer that stimulates macrophages to release tumor necrosis factor-α (TNF-α). In macrophages (RAW 264.7 and peritoneal cells), LPS binds to the CD14 surface receptor as the first step toward signaling. Liver macrophages, Kupffer cells, are the most numerous fixed-tissue macrophage in the body. The presence of CD14 on Kupffer cells and its role in LPS stimulation of TNF-α were examined. TNF-α release by Kupffer cells after LPS stimulation was the same in the presence and absence of serum. RAW 264.7 and peritoneal cells, which utilize the CD14 receptor, released significantly less TNF-α after LPS stimulation in the absence of serum because of the absence of LPS-binding protein. Phosphatidylinositol-phospholipase C treatment, which cleaves the CD14 receptor, decreased LPS-stimulated TNF-α release by RAW 264.7 cells but not by Kupffer cells. Deacylated LPS (dLPS) competes with LPS at the CD14 receptor when incubated in a ratio of 100:1 (dLPS/LPS). Such competition blocked LPS-stimulated TNF-α release from RAW 264.7 cells but not from Kupffer cells. Western and fluorescence-activated cell sorter analysis directly demonstrated the presence of CD14 on RAW 264.7 cells and murine peritoneal cells but showed only minimal amounts of CD14 in murine Kupffer cells. LPS stimulation did not increase the amount of CD14 detectable on mouse Kupffer cells. CD14 expression is very low in Kupffer cells, and LPS-stimulated TNF-α release is independent of CD14 in these cells.


1999 ◽  
Vol 276 (3) ◽  
pp. G591-G598 ◽  
Author(s):  
Kenichi Ikejima ◽  
Nobuyuki Enomoto ◽  
Vitor Seabra ◽  
Ayako Ikejima ◽  
David A. Brenner ◽  
...  

CD14 is a lipopolysaccharide (LPS) receptor distributed largely in macrophages, monocytes, and neutrophils; however, the role of CD14 in activation of Kupffer cells by LPS remains controversial. The purpose of this study was to determine if different methods used to isolate Kupffer cells affect CD14. Kupffer cells were isolated by collagenase (0.025%) or collagenase-Pronase (0.02%) perfusion and differential centrifugation using Percoll gradients and cultured for 24 h before experiments. CD14 mRNA was detected by RT-PCR from Kupffer cell total RNA as well as from peritoneal macrophages. Western blotting showed that Kupffer cells prepared with collagenase possess CD14; however, it was absent in cells obtained by collagenase-Pronase perfusion. Intracellular calcium in Kupffer cells prepared with collagenase was increased transiently to levels around 300 nM by addition of LPS with 5% rat serum, which contains LPS binding protein. This increase in intracellular calcium was totally serum dependent. Moreover, LPS-induced increases in intracellular calcium in Kupffer cells were blunted significantly (40% of controls) when cells were treated with phosphatidylinositol-specific phospholipase C, which cleaves CD14 from the plasma membrane. However, intracellular calcium did not increase when LPS was added to cells prepared by collagenase-Pronase perfusion even in the presence of serum. These cells were viable, however, because ATP increased intracellular calcium to the same levels as cells prepared with collagenase perfusion. Tumor necrosis factor-α (TNF-α) mRNA was increased in Kupffer cells prepared with collagenase perfusion 1 h after addition of LPS, an effect potentiated over twofold by serum; however, serum did not increase TNF-α mRNA in cells isolated via collagenase-Pronase perfusion. Moreover, treatment with Pronase rapidly decreased CD14 on mouse macrophages (RAW 264.7 cells) and Kupffer cells. These findings indicate that Pronase cleaves CD14 from Kupffer cells, whereas collagenase perfusion does not, providing an explanation for why Kupffer cells do not exhibit a CD14-mediated pathway when prepared with procedures using Pronase. It is concluded that Kupffer cells indeed contain a functional CD14 LPS receptor when prepared gently.


Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 576 ◽  
Author(s):  
Hongju Liu ◽  
Chong Yan ◽  
Changqun Li ◽  
Tingting You ◽  
Zhigang She

Twelve 1, 4-naphthoquinone derivatives, including two new (1 and 2) and 10 known (3–12), were obtained from endophytic fungus Talaromyces sp. SK-S009 isolated from the fruit of Kandelia obovata. All structures were identified through extensive analysis of the nuclear magnetic resonance (NMR), mass spectrometry (MS) and circular dichroism (CD), as well as by comparison with literature data. These compounds significantly inhibited the lipopolysaccharide (LPS)-induced nitric oxide (NO) production in the murine macrophage cell line (RAW 264.7 cells). The half maximal inhibitory concentration (IC50) values, except for compound 2, were lower than that of indomethacin (26.3 μM). Compound 9 inhibited the LPS-induced inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) mRNA expressions in RAW 264.7 macrophages. Additionally, compound 9 reduced the mRNA levels of pro-inflammatory factors interleukin (IL)1β, IL-6, and tumor necrosis factor (TNF)-α. The results of this study demonstrated that these 1, 4-naphthoquinone derivatives can inhibit LPS-induced inflammation.


Author(s):  
Saranya Arumugam ◽  
Ramanathan Thiruganasambantham

Objective: Acanthus ilicifolius Linn. (Acanthaceae) is a medicinal mangrove plant used in the treatment of inflammation. Previous phytochemical studies have identified 2-benzoxazolinone (BOA) from the leaves of A. ilicifolius. In the present study, we attempted to standardize the supercritical CO2 leaf extract of A. ilicifolius (SCFE-AI) for BOA content and investigate the tumor necrosis factor-α (TNF-α) inhibitory effect of SCFE-AI and BOA on the lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 macrophages. The acute oral toxicity of SCFE-AI and BOA was also established.Methods: SCFE-AI was standardized for BOA content using high-performance thin-layer chromatography (HPTLC) method. The cytotoxicity of SCFE-AI and BOA was evaluated using MTS colorimetric method. The in vitro anti-inflammatory effect of SCFE-AI and BOA on TNF-α production in LPS-activated RAW 264.7 cells was quantified using ELISA method. Acute oral toxicity studies were performed following the Organization for Economic Co-operation and Development test guideline No. 423.Results: The amount of BOA was found 0.8% w/w of SCFE-AI. The RAW 264.7 cell viability was unaffected by SCFE-AI and BOA treatments within a concentration range <1000 mg/ml after 24 h incubation. SCFE-AI decreased the production of TNF-α in a dose-dependent manner compared to BOA. The LD50 value for SCFE-AI was found to be >2000 mg/kg and ranges from 300 to 2000 mg/kg with BOA.Conclusion: The HPTLC chromatogram could serve as an analytical tool for authentication and quantification of BOA content. The anti-inflammatory mechanism of A. ilicifolius might be through the inhibition of TNF-α production.


2002 ◽  
Vol 283 (1) ◽  
pp. R218-R226 ◽  
Author(s):  
Alexander V. Gourine ◽  
Valery N. Gourine ◽  
Yohannes Tesfaigzi ◽  
Nathalie Caluwaerts ◽  
Fred Van Leuven ◽  
...  

α2-Macroglobulin (α2M) is not only a proteinase inhibitor in mammals, but it is also a specific cytokine carrier that binds pro- and anti-inflammatory cytokines implicated in fever, including interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α). To define the role of α2M in regulation of febrile and cytokine responses, wild-type mice and mice deficient in α2M (α2M −/−) were injected with lipopolysaccharide (LPS). Changes in body temperature as well as plasma levels of IL-1β, IL-6, and TNF-α and hepatic TNF-α mRNA level during fever in α2M −/− mice were compared with those in wild-type control mice. The α2M −/− mice developed a short-term markedly attenuated (ANOVA, P < 0.05) fever in response to LPS (2.5 mg/kg ip) compared with the wild-type mice. At 1.5 h after injection of LPS, the plasma concentration of TNF-α, but not IL-1β or IL-6, was significantly lower (by 58%) in the α2M −/− mice compared with their wild-type controls (ANOVA, P < 0.05). There was no difference in hepatic TNF-α mRNA levels between α2M −/− and wild-type mice 1.5 h after injection of LPS. These data support the hypotheses that 1) α2M is important for the normal development of LPS-induced fever and 2) a putative mechanism of α2M involvement in fever is through the inhibition of TNF-α clearance. These findings indicate a novel physiological role for α2M.


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