Isofraxidin exhibited anti-inflammatory effects in vivo and inhibited TNF-α production in LPS-induced mouse peritoneal macrophages in vitro via the MAPK pathway

Isofraxidin (IF) is a Coumarin compound that can be isolated from medicinal plants, such as Sarcandra glabra (Thunb.). Nakai is widely used in Asian countries for the treatment of anti-bacterial, anti-inflammatory and anti-tumour action. The present investigation was designed to evaluate the effect of IF on inflammation and nociception. In addition, we investigated a potential novel mechanism to explain the anti-inflammatory properties of IF. In vivo, xylene-induced mouse ear edema, carrageenan-induced rat paw edema, LPS-induced mouse endotoxic shock, acetic acid-induced mice writhing and formalin-induced mouse pain models were used to evaluate the anti-inflammatory activity of IF. In vitro, we examined the effects of IF inhibition on TNF-α production and the regulation of ERK1/2 and p38 phosphorylation activity in LPS-induced mouse peritoneal macrophages. Our results demonstrated that IF can significantly decrease xylene-induced ear edema, carrageenan-induced paw edema, acetic acid-induced writhing and formalin-induced pain. Moreover, IF greatly inhibited the production of TNF-α in the serum of LPS-stimulated mice and peritoneal macrophages, and it decreased phospho-p38 and ERK1/2 protein expression in LPS-stimulated mouse peritoneal macrophages. Overall, our data suggest that IF possesses significant analgesic and anti-inflammatory activities that may be mediated through the regulation of pro-inflammatory cytokines, TNF-α and the phosphorylation of p38 and ERK1/2.     

Glycine inhibits the LPS-induced increase in cytosolic Ca2+ concentration and TNFα production in cardiomyocytes by activating a glycine receptor

Aim:

Previous studies have demonstrated that glycine (GLY) markedly reduces lipopolysaccharide (LPS)-induced myocardial injury. However, the mechanism of this effect is still unclear. The present study investigated the effect of GLY on cytosolic calcium concentration ([Ca²⁺]_c) and tumor necrosis factor-α (TNFα) production in cardiomyocytes exposed to LPS, as well as whether the glycine-gated chloride channel is involved in this process.

Methods:

Neonatal rat cardiomyocytes were isolated, and the [Ca²⁺]_c and TNFα levels were determined by using Fura-2 and a Quantikine enzyme-linked immunosorbent assay, respectively. The distribution of the GLY receptor and GLY-induced currents in cardiomyocytes were also investigated using immunocytochemistry and the whole-cell patch-clamp technique, respectively.

Results:

LPS at concentrations ranging from 10 ng/mL to 100 μg/mL significantly stimulated TNFα production. GLY did not inhibit TNFα production induced by LPS at concentrations below 10 ng/mL but did significantly decrease TNFα release stimulated by 100 μg/mL LPS and prevented an LPS-induced increase in [Ca²⁺]_c, which was reversed by strychnine, a glycine receptor antagonist. GLY did not block the isoproterenol-induced increase in [Ca²⁺]_c, but did prevent the potassium chloride-induced increase in [Ca²⁺]_c in cardiomyocytes. Strychnine reversed the inhibition of the KCl–stimulated elevation in [Ca²⁺]_c by GLY. In chloride-free buffer, GLY had no effect on the dipotassium hydrogen phosphate-induced increase in [Ca²⁺]_c. Furthermore, GLY receptor α₁ and β subunit-immunoreactive spots were observed in cardiomyocytes, and GLY-evoked currents were blocked by strychnine.

Conclusion:

Cardiomyocytes possess the glycine-gated chloride channel, through which GLY prevents the increase in [Ca²⁺]_c and inhibits the TNFα production induced by LPS at high doses in neonatal rat cardiomyocytes.     

Glycine inhibits the LPS-induced increase in cytosolic Ca^2＋ concentration and TNFα production in cardiomyocytes by activating a glycine receptor

Aim： Previous studies have demonstrated that glycine （GLY） markedly reduces lipopolysaccharide （LPS）-induced myocardial injury. However, the mechanism of this effect is still unclear. The present study investigated the effect of GLY on cytosolic calcium concentration （[Ca^2＋]c） and tumor necrosis factor-α（TNFα） production in cardiomyocytes exposed to LPS, as well as whether the glycine-gated chloride channel is involved in this process. Methods： Neonatal rat cardiomyocytes were isolated, and the [Ca^2＋]c and TNFα levels were determined by using Fura-2 and a Quan tikine enzyme-linked immunosorbent assay, respectively. The distribution of the GLY receptor and GLY-induced currents in cardiomyocytes were also investigated using immunocytochemistry and the whole-cell patch-clamp technique, respectively. Results： LPS at concentrations ranging from 10 ng/mL to 100 pg/mL significantly stimulated TNFα production. GLY did not inhibit TNFα production induced by LPS at concentrations below 10 ng/mL but did significantly decrease TNFα release stimulated by 100 pg/mL LPS and prevented an LPS-induced increase in [Ca^2＋]c, which was reversed by strychnine, a glycine receptor antagonist. GLY did not block the isoproterenol-induced increase in [Ca^2＋]c, but did prevent the potassium chloride-induced increase in [Ca2＋]cin cardiomyocytes. Strychnine reversed the inhibition of the KCl-stimulated elevation in [Ca^2＋]cby GLY. In chloride-free buffer, GLY had no effect on the dipotassium hydrogen phosphate-induced increase in [Ca^2＋]c. Furthermore, GLY receptor α1 and β subunitimmunoreactive spots were observed in cardiomyocytes, and GLY-evoked currents were blocked by strychnine. Conclusion： Cardiomyocytes possess the glycine-gated chloride channel, through which GLY prevents the increase in [Ca^2＋]c and inhibits the TNFα production induced by LPS at high doses in neonatal rat cardiomyocytes.     

IFN-γ differentially modulates TGF-β production in human airway epithelial and mesenchymal cells by targeting Smads

RATIONALE: IFN-γ regulates inflammatory responses and also may attenuate the fibrotic process. The production of TGF-βs by bronchial epithelial cells and lung mesenchymal cells may be important in modulating both airway inflammation and remodeling. Therefore, we hypothesized that IFN-γ may regulate TGF-β production     

Upregulation of TNF-α and IL-6 mRNA in mouse liver induced by bacille Calmette-Guerin plus lipopolysaccharide

AIM: To investigate the mechanism of immunological liver injury induced by bacille Calmette-Guerin (BCG) plus lipopolysaccharide (LPS). METHODS: Mice were injected via the tail vein with 125 mg/kg BCG, and 12 d later, the mice were injected intravenously with different doses of LPS (125, 250, or 375 microg/kg). Serum alanine aminotransferase (ALT) activity and liver pathological changes were examined. The expression of tumor necrosis factor (TNF)- alpha, interleukin (IL)-6, lipopolysaccharide binding protein (LBP) and CD14 mRNA, and NF-kappaB and IkappaB-alpha protein in mouse liver at different time points after BCG and LPS injection were measured using RT-PCR, immunohistochemistry and Western blotting analysis, respectively. RESULTS: The activity of serum ALT in mice treated with BCG and LPS was significantly increased. Different degrees of liver injury, such as inflammatory cell infiltration, spotty necrosis, piecemeal necrosis, even bridging necrosis, could be seen in liver sections from mice after BCG and LPS administration. Furthermore, the levels of TNF-alpha and IL-6 mRNA in mouse liver were significantly elevated after administration of BCG plus LPS (P<0.05). The levels of LBP and CD14 mRNA in mouse liver were markedly upregulated after treatment with BCG and LPS, and treatment with BCG alone led to an increase in CD14 mRNA in mouse liver. Finally, immunoreactivity for NF-kappaB p65 was predominantly detected in hepatocyte nuclei from mice treated with BCG plus LPS, compared with the normal group. Protein levels of IkappaB-alpha were strikingly decreased by LPS or BCG plus LPS treatment, compared with the normal group or BCG group. CONCLUSION: TNF-alpha and IL-6 mRNA were partially involved in early immunological liver injury induced by challenge with small doses of LPS after BCG priming. Upregulation of TNF-alpha and IL-6 mRNA might be related to increases in LBP and CD14 mRNA expression and activation of NF-kappaB. Furthermore, BCG priming in immunological liver injury may occur via upregulation of CD14 mRNA expression in mononuclear cell infiltration into the liver.     

Effect of Liposomal and Free Bisphosphonates on the IL-1β, IL-6 and TNFα Secretion from RAW 264 Cells in Vitro

Purpose. In order to evaluate the possible antiinflammatory action of bisphosphonates, the effect of the drugs on the secretion of proinflammatory cytokines (IL-l, IL-6 and TNF) from macrophages was studied. Liposomes or high concentration of extracellular calcium was used to enhance the intracellular delivery of bisphosphonates. Methods. RAW 264 cells were used as macrophage model, and they were induced with lipopolysaccharide to produce the cytokines. The cytokine concentrations in the culture supernatants were measured with time-resolved fluoroimmunoassay. Results. As a free drug, clodronate and pamidronate, but not etidronate, inhibited LPS-stimulated secretion of the cytokines from macrophage-like RAW 264 cells. Low concentrations of pamidronate, however, induced the IL-6 secretion, and the cytokine inhibitory action at the higher concentrations of pamidronate was attributed to cytotoxicity of the compound. The cytokine induction or toxic effects were not observed with clodronate or etidronate. When the drugs were encapsulated in negatively charged unilamellar liposomes, the inhibitory potency of both clodronate and etidronate enhanced by a factor of 10-20, while that of pamidronate was not increased. The complex formation of bisphosphonates with extracellular calcium, although enhancing the uptake of the compounds by macrophages, did not considerably increase their cytokine inhibitory potency. Conclusions. Bisphosphonates have inhibitory action on cytokine secretion by macrophages. The non-cytotoxic cytokine inhibition by liposome encapsulated clodronate could be beneficial in local inflammatory diseases, where the inflammation is sustained by the excessive amounts of inflammatory cytokines produced by activated macrophages.     

HIV protease inhibitor lopinavir-induced TNF-α and IL-6 expression is coupled to the unfolded protein response and ERK signaling pathways in macrophages

HIV protease inhibitor (PI)-associated cardiovascular risk, especially atherosclerosis, has become a major concern in the clinic. Macrophages are key players in the inflammatory response and atherosclerosis formation. We have previously shown that HIV PIs induce endoplasmic reticulum (ER) stress, activate the unfolded protein response (UPR), and increase the synthesis of the inflammatory cytokines, TNF-α and IL-6, by regulating the intracellular translocation of RNA binding protein HuR in macrophages. However, the underlying signaling mechanisms remain unclear. We show here that the HIV PI lopinavir significantly activated the extracellular-signal regulated protein kinase (ERK), but not c-Jun N-terminal kinase (JNK) and p38 MAPK. Lopinavir-induced cytosolic translocation of HuR and TNF-α and IL-6 synthesis was attenuated by specific chemical inhibitor of MEK (PD98058) or over-expression of dominant negative mutant of MEK1. In addition, we demonstrated that lopinavir-induced ERK activation and TNF-α and IL-6 expression were completely inhibited in macrophages from CHOP null mice. Taken together, these results indicate activation of the UPR plays an essential role in HIV PI-induced inflammatory cytokine synthesis and release by activating ERK, which increases the cytosolic translocation of HuR and subsequent binding to the 3′UTR of TNF-α and IL-6 mRNAs in macrophages.     

Tephrosia sinapou ethyl acetate extract inhibits inflammatory pain in mice: Opioid receptor dependent inhibition of TNFα and IL-1β production

Abstract

Context. Tephrosia toxicaria is currently known as Tephrosia sinapou (Buc'hoz) A. Chev. (Fabaceae) and is a source of compounds such as flavonoids that inhibit inflammatory pain.

Objective: To investigate the analgesic effect and mechanisms of the ethyl acetate extract of T. sinapou in inflammatory pain in mice.

Materials and methods: Behavioral responses were evaluated using mechanical (1–24?h) and thermal hyperalgesia (0.5–5?h), writhing response (20?min) and rota-rod (1–5?h) tests. Neutrophil recruitment (myeloperoxidase activity), cytokines (tumor necrosis factor [TNF]α and interleukin [IL]-1β), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) serum levels were determined by colorimetric assays. Pharmacological treatments were opioid receptor antagonist (naloxone, 0.1–1?mg/kg) and control opioid (morphine, 5?mg/kg). Inflammatory stimuli were carrageenin (100?µg/paw), complete Freund’s adjuvant (CFA, 10?µl/paw), prostaglandin E₂ (PGE₂, 100?ng/paw) and acetic acid (0.8%).

Results: The intraperitoneal pre-treatment with extract inhibited in a dose-dependent (30–300?mg/kg) dependent manner the mechanical hyperalgesia induced by carrageenin (up to 93% inhibition). The post-treatment (100?mg/kg) inhibited CFA-induced hyperalgesia (up to 63% inhibition). Naloxone (1?mg/kg) prevented the inhibitory effect of the extract over carrageenin-induced mechanical (100%) and thermal (100%) hyperalgesia, neutrophil recruitment (52%) and TNFα (63%) and IL-1β (98%) production, thermal threshold in naïve mice (99%), PGE₂-induced mechanical hyperalgesia (88%) and acetic acid-induced writhing response (49%). There was no significant alteration in the rota-rod test, and AST and ALT serum levels by extract treatment.

Discussion and conclusion. Tephrosia sinapou ethyl acetate extract reduces inflammatory pain by activating an opioid receptor-dependent mechanism.     

Inhibitory effects of nitric oxide and interleukin-10 on production of tumor necrosis factorα,interleukin-1β,and interleukin-6 in mouse alveolar macrophages

目的：观察一氧化氮和ＩＬ１０对肺泡巨噬细胞炎症反应的调节作用．方法：小鼠肺泡巨噬细胞（ＡＭ）受脂多糖（ＬＰＳ）１０ｍｇ·Ｌ－１刺激同时,加入一氧化氮合酶抑制剂Ｓ硫酸甲基异硫脲（ＳＭＴ）或一氧化氮供体Ｓ亚硝基乙酰青霉胺（ＳＮＡＰ）．ＥＬＩＳＡ法测定上清液中ＴＮＦα、ＩＬ１β、ＩＬ６和ＩＬ１０浓度．结果：ＡＭ受ＬＰＳ刺激后,ＴＮＦα、ＩＬ１β和ＩＬ６释放峰值分别在６、１２和２４小时．ＳＭＴ抑制一氧化氮释放,但促进ＩＬ１β和ＩＬ６释放,对ＴＮＦα无影响．ＳＮＡＰ对ＩＬ１β和ＩＬ６释放有明显的抑制作用,呈剂量依赖效应．重组ＩＬ１０抑制ＴＮＦα、ＩＬ１β和ＩＬ６释放,而ＩＬ１０单克隆抗体促进上述因子释放．结论：内源及外源性一氧化氮和ＩＬ１０均对ＬＰＳ诱导的炎症性细胞因子释放有抑制作用．     

Blockade of IL-6 and TNF-α inhibited oxLDL-induced production of MCP-1 via scavenger receptor induction

In chronic inflammatory diseases, cardiovascular disease risk is increased and is the main cause of increased mortality. Oxidized LDL (oxLDL) and scavenger receptors participate in atherogenesis. Using human arterial endothelial cells (HAECs), we evaluated the effect of IL-6 and TNF-α on the expression of scavenger receptors. IL-6 induced expression of SR-A mRNA and TNF-α induced both SR-A and LOX-1 mRNA. Both did induce either CD36 or CD68. To assess the function of scavenger receptors, MCP-1 production by oxLDL from cytokine-pretreated HAEC was examined. In accordance with scavenger receptor expression, oxLDL-induced MCP-1 production was increased in IL-6- or TNF-α-pretreatment. Serum from rheumatoid arthritis patients but not from healthy subjects increased mRNA expressions of SR-A, LOX-1 and CD36 in HAEC. SR-A expression was inhibited by both anti-IL-6 receptor antibody (α-IL-6R Ab) and TNF-α receptor (p75)-Fc (TNFR-Fc) and LOX-1 expression was inhibited by TNFR-Fc. CD36 expression was affected by neither. Serum from rheumatoid arthritis patients augmented oxLDL-induced MCP-1 production. Both α-IL-6R Ab and TNFR-Fc partially inhibited this MCP-1 production. In conclusion, our results strongly support that blocking therapy of IL-6 and TNF-α might be beneficial to reduce atherosclerosis risk in chronic inflammatory diseases.     

D(−)-Salicin inhibits the LPS-induced inflammation in RAW264.7 cells and mouse models

D(−)-Salicin is a traditional medicine which has been known to exhibit anti-inflammation and other therapeutic activities. The present study aimed to investigate whether D(−)-Salicin inhibited the LPS-induced inflammation in vivo and in vitro. We evaluated the effect of D(−)-Salicin on cytokines (TNF-α, IL-1β, IL-6 and IL-10) in vivo and in vitro by enzyme-linked immunosorbent assay and signaling pathways (MAPKs and NF-κB) in vivo by Western blot. The results showed that D(−)-Salicin markedly decreased TNF-α, IL-1β and IL-6 concentrations and increased IL-10 concentration. In addition, western blot analysis indicated that D(−)-Salicin suppressed the activation of MAPKs and NF-κB signaling pathways stimulated by LPS. To examine whether D(−)-Salicin ameliorated LPS-induced lung inflammation, inhibitors of MAPKs and NF-κB signaling pathways were administrated intraperitoneally to mice. Interference with specific inhibitors revealed that D(−)-Salicin-mediated cytokine suppression was through MAPKs and NF-κB pathways. In the mouse model of acute lung injury, histopathologic examination indicted that D(−)-Salicin suppressed edema induced by LPS. So it is suggest that D(−)-Salicin might be a potential therapeutic agent against inflammatory diseases.     

Paeoniflorin improves survival in LPS-challenged mice through the suppression of TNF-α and IL-1β release and augmentation of IL-10 production

Lipopolysaccharide (LPS) plays an important role in Gram-negative bacteria-induced sepsis and multiple organ dysfunction syndrome, which are still the leading cause of high mortality in intensive care units. Although paeoniflorin (Pae) has reportedly exhibited anti-inflammatory effect and protection against immunological liver injury in mice, it is not known whether Pae improve survival in endotoxemic mice. The purpose of this study was to determine the effect of Pae on the mortality, multiple organ dysfunction and cytokine production in lipopolysaccharide (LPS)-treated mice. We found that pretreatment with Pae decreased mortality, reduced lung and kidney injury, decreased serum creatinine level and improve systolic function of heart in mice challenged with LPS. Further experiments showed that Pae inhibited LPS-stimulated tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) release and promoted LPS-induced interleukin-10 (IL-10) production. Our results indicate that Pae protects mice against lethal LPS challenge, at least in part, through inhibiting TNF-α and IL-1β production and accelerating IL-10 expression.     

Pristimerin,a natural anti-tumor triterpenoid,inhibits LPS-induced TNF-α and IL-8 production through down-regulation of ROS-related classical NF-κB pathway in THP-1 cells

Pristimerin, a naturally occurring quinonemethide triterpenoid compound, is known to exert a variety of pharmacological activities. In the present study, we investigated the molecular actions of pristimerin against LPS-induced inflammatory responses in human monocytic THP-1 cells. The results showed that pristimerin inhibited the production of TNF-α and IL-8 in a dose-dependent manner. To explore the possible mechanisms underlying these inhibitions by pristimerin, we examined the intracellular ROS level and the NF-κB protein signaling pathway. Pristimerin clearly scavenged LPS-induced intracellular ROS production. In addition, pristimerin prevented LPS-induced NF-κB activation through the inhibition of phosphorylation of IKKα/β, phosphorylation and degradation of IκBα, as well as phosphorylation and nuclear translocation of NF-κB p65. These findings suggest that pristimerin down-regulates the expression of pro-inflammatory mediators through blocking of NF-κB activation by inhibiting interconnected ROS/IKK/NF-κB signaling pathways.