Cross-Regulation of iNOS and COX-2 by its Products in Murine Macrophages Under Stress Conditions

Vanillin protects lipopolysaccharide-induced acute lung injury by inhibiting ERK1/2, p38 and NF-κB pathway

Aim: Thus far, the anti-inflammatory effect of vanillin in acute lung injury (ALI) has not been studied. This study aimed to investigate the effect of vanillin in lipopolysaccharide (LPS)-induced ALI. Results & methodology: Our study detected the anti-inflammatory effects of vanillin by ELISA and western blot, respectively. Pretreatment of mice with vanillin significantly attenuated LPS-stimulated lung histopathological changes, myeloperoxidase activity and expression levels of proinflammatory cytokines by inhibiting the phosphorylation activities of ERK1/2, p38, AKT and NF-κB p65. In addition, vanillin inhibited LPS-induced TNF-α and IL-6 expression in RAW264.7 cells via ERK1/2, p38 and NF-κB signaling. Conclusion: Vanillin can inhibit macrophage activation and lung inflammation, which suggests new insights for clinical treatment of ALI.

Direct treatment versus indirect: Thermo-ablative and mild hyperthermia effects

Hyperthermia is a rapidly growing field in cancer therapy and many advances have been made in understanding and applying the mechanisms of hyperthermia. Secondary effects of hyperthermia have been increasingly recognized as important in therapeutic effects and multiple studies have started to elucidate their implications for treatment. Immune effects have especially been recognized as important in the efficacy of hyperthermia treatment of cancer. Both thermo-ablative and mild hyperthermia activate the immune system, but mild hyperthermia seems to be more effective at doing so. This may suggest that mild hyperthermia has some advantages over thermo-ablative hyperthermia and research into immune effects of mild hyperthermia should continue. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies Implantable Materials and Surgical Technologies > Nanoscale Tools and Techniques in Surgery.

Inhibition of HSP90β by ganetespib blocks the microglial signalling of evoked pro-inflammatory responses to heat shock

Although microglial reaction to heat shock is considered to be protective, heat shock is still a potential hazard caused by high temperatures. Recent studies indicate that the inhibition of the 90-kDa heat shock protein (HSP90) increasing the protective heat shock response and suppressing inflammatory signalling pathways in several diseases. Nevertheless, the effects of heat shock on microglial pro-inflammatory responses are not completely identical. Here, we aim to investigate the effect of the HSP90 inhibitor ganetespib on microglial pro-inflammatory responses following heat shock. HSP90 isoforms were determined by transfecting N9 microglial cells (N9 cells) with enzymatically prepared siRNA (esiRNAs). We found that heat shock significantly increased the secretion of tumour necrosis factor alpha (TNF-α), interleukin (IL)-1β, IL-6 and nitric oxide (NO), and the phosphorylation of extracellular signal-regulated kinase (ERK), Janus-activated kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3), nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor alpha (IκB-α) and p65 nuclear factor kappa-light-chain-enhancer of activated B cells (p65 NF-κB) in N9 cells. These increases, except for phospho-p65, were attenuated efficiently in a dose-dependent manner by ganetespib pretreatment. Furthermore, the suppression of heat shock-evoked cytokines and NO production, and the phosphorylation of ERK, JAK2 and STAT3 in cytosols and/or nuclei were also observed by administering esiRNA HSP90β, but not HSP90α, in heat shock-treated N9 cells. Taken together, our findings demonstrate that the HSP90 inhibitor ganetespib blocks pro-inflammatory responses in heat shock-treated N9 cells via a signalling mechanism involving HSP90β and STAT3.

Immunogenic Effect of Hyperthermia on Enhancing Radiotherapeutic Efficacy

Hyperthermia is a cancer treatment where tumor tissue is heated to around 40 °C. Hyperthermia shows both cancer cell cytotoxicity and immune response stimulation via immune cell activation. Immunogenic responses encompass the innate and adaptive immune systems, involving the activation of macrophages, natural killer cells, dendritic cells, and T cells. Moreover, hyperthermia is commonly used in combination with different treatment modalities, such as radiotherapy and chemotherapy, for better clinical outcomes. In this review, we will focus on hyperthermia-induced immunogenic effects and molecular events to improve radiotherapy efficacy. The beneficial potential of integrating radiotherapy with hyperthermia is also discussed.

Intrauterine Malnutrition Reduced Long Leptin Receptor Isoform Expression and Proinflammatory Cytokine Production in Male Rat Pulmonary Endothelial Cells Stimulated by Lipopolysaccharide

Background/Aims

We have previously shown that low birth weight (LBW) rats exposed to intrauterine malnutrition have an impaired lung inflammatory response and reduced levels of inflammatory mediators; however, circulating leptin levels were not increased. We evaluated long leptin receptor isoform (ObRb) expression in lung endothelial cells from low birth weight rats and examined its role in the production of lipid mediators and cytokines.

Methods

Lung endothelial cells were obtained from normal birth weight (NBW) rats or LBW rats subjected to intrauterine malnutrition. These cells were stimulated with leptin (10 ng/mL), LPS (lipopolysaccharide, 1 μg/mL), or leptin plus LPS. Six hours after stimulation, the production of inflammatory mediators (PGE₂, LTB₄, IL-1β, and IL-6) was evaluated using commercial ELISA kits, and Western blotting was performed to investigate p38MAPK, NF-κB, and ObRb expression.

Results

Leptin increased IL-1β levels in only cells from the NBW group, whereas LPS increased PGE₂ and LTB₄ levels in cells from both groups; leptin addition potentiated lipid mediator production induced by LPS in the NBW group. LPS enhanced the production of IL-1β and IL-6 in only endothelial cells from NBW rats. Leptin receptor expression was decreased (63%) in endothelial cells from LBW rats. None of the stimuli increased NF-κB or p38 signaling pathway expression in cells from LBW rats.

Conclusion

These results suggest that intrauterine malnutrition compromises leptin receptor expression and cytokine production in pulmonary endothelial cells stimulated by LPS; these effects seem to involve the NF-κB and p38MAPK signaling pathways.

Allogeneic Adipose-Derived Mesenchymal Stromal Cells Ameliorate Experimental Autoimmune Encephalomyelitis by Regulating Self-Reactive T Cell Responses and Dendritic Cell Function

Multipotent mesenchymal stromal cells (MSCs) have emerged as a promising therapy for autoimmune diseases, including multiple sclerosis (MS). Administration of MSCs to MS patients has proven safe with signs of immunomodulation but their therapeutic efficacy remains low. The aim of the current study has been to further characterize the immunomodulatory mechanisms of adipose tissue-derived MSCs (ASCs) in vitro and in vivo using the EAE model of chronic brain inflammation in mice. We found that murine ASCs (mASCs) suppress T cell proliferation in vitro via inducible nitric oxide synthase (iNOS) and cyclooxygenase- (COX-) 1/2 activities. mASCs also prevented the lipopolysaccharide- (LPS-) induced maturation of dendritic cells (DCs) in vitro. The addition of the COX-1/2 inhibitor indomethacin, but not the iNOS inhibitor L-NAME, reversed the block in DC maturation implicating prostaglandin (PG) E₂ in this process. In vivo, early administration of murine and human ASCs (hASCs) ameliorated myelin oligodendrocyte protein- (MOG_35-55-) induced EAE in C57Bl/6 mice. Mechanistic studies showed that mASCs suppressed the function of autoantigen-specific T cells and also decreased the frequency of activated (CD11c⁺CD40^high and CD11c⁺TNF-α⁺) DCs in draining lymph nodes (DLNs). In summary, these data suggest that mASCs reduce EAE severity, in part, through the impairment of DC and T cell function.

BaeR protein acts as an activator of nuclear factor-kappa B and Janus kinase 2 to induce inflammation in murine cell lines

BaeR, a response regulator protein, takes part in multidrug efflux, bacterial virulence activity, and other biological functions. Recently, BaeR was shown to induce inflammatory responses by activating the mitogen-activated protein kinases (MAPKs). In this study, we investigated additional pathways used by BaeR to induce an inflammatory response. BaeR protein was purified from Salmonella enterica Paratyphi A and subcloned into a pPosKJ expression vector. RAW 264.7 cells were treated with BaeR, and RNA was extracted by TRIzol reagent for RT-PCR. Cytokine gene expression was analyzed by using the comparative cycle threshold method, while western blotting and ELISA were used to assess protein expression. We confirmed that BaeR activates nuclear factor-kappa B (NF-κB), thereby inducing an inflammatory response and increases the production of interleukins (IL-)1β and IL-6. During this process, the Janus kinase 2 (JAK2)-STAT1 signaling pathway was activated, resulting in an increase in the release of interferons I and II. Additionally, COX-2 was activated and its expression increased with time. In conclusion, BaeR induced an inflammatory response through activation of NF-κB in addition to the MAPKs. Furthermore, activation of the JAK2-STAT1 pathway and COX-2 facilitated the cytokine binding activity, suggesting an additional role for BaeR in the modulation of the immune system of the host and the virulence activity of the pathogen.

Anti-inflammatory properties of convolutamydine A and two structural analogues

AIMS

Convolutamydine A is an oxindole alkaloid that can be isolated from a marine bryozoan. Due to the variety of biological effects, two analogues were synthesized and their anti-inflammatory properties were evaluated.

MAIN METHODS

The anti-inflammatory effects of convolutamydine A and its analogues (ISA003 and ISA147) were investigated in a formalin-induced licking behaviour model, where mice received an intraplantar injection of formalin and their licking behaviour was evaluated for 30min. Additionally, inflammatory parameters were evaluated in a subcutaneous air pouch (SAP) model of carrageenan-induced inflammation. Exudates were collected for leukocyte counts; measurement of protein, prostaglandin E2 (PGE2) and cytokines by ELISA; and analysis of nitric oxide (NO) using a nitrate conversion protocol. Cyclooxygenase-2 (COX2) and inducible nitric oxide synthase (iNOS) from RAW 264.7 cells were quantified by immunoblotting.

KEY FINDINGS

Convolutamydine A and its two analogues inhibited the formalin-induced licking response at doses as low as 0.01mg/kg. An inhibitory effect was also observed on leukocyte migration and the production of NO, PGE2 and cytokines (IL-6 and TNF-α). The reduction in inflammatory parameters did not appear to be correlated with a direct reduction in the number of cells in the SAP, because a reduction in NO and PGE2 production by cultured macrophages was observed in addition to the inhibition of iNOS and COX2 enzyme expression.

SIGNIFICANCE

These results indicate that convolutamydine A and its two analogues have significant anti-inflammatory effects. These substances can be improved to generate lead compounds for the synthesis of new anti-inflammatory drugs.

Characterization of the inflammatory response during Ehrlich ascitic tumor development

INTRODUCTION

Ehrlich tumor is a mammary adenocarcinoma with aggressive behavior. Inoculated in mice peritoneal cavity, the Ehrlich tumor grows in ascitic form (EAT). Since inflammation modulates tumor progression we further investigated the inflammatory response during EAT growth.

METHODS

Balb/C mice were intraperitoneal inoculated with 5×10(5) Ehrlich cells and after every 2days, blood samples were collected for hemoglobin, hematocrit, platelets and leukocytes counts. The ascitic fluid was collected for protein concentration and cell count. Phenotype analysis of the peritoneal cells was made by FACS, prostaglandin E2 (PGE2) and cytokines by ELISA, nitric oxide (NO) by nitrate conversion protocol, and cyclooxygenase-1 (COX1), COX2 and inducible nitric oxide synthase (iNOS) by immunoblotting.

RESULTS

Following EAT inoculation into the peritoneal cavity there was a rapid increase in ascitis volume and protein concentration. The cell number in ascitis remained stable until day 8 (lag phase) followed by a sharp increase. As tumor progressed, blood leukocytes increased and erythrocyte decreased. Phenotypic analysis showed that during the lag phase the percentage of F4/80(+) cells remained similar to control levels and around 7% of this population was also positive for the GR1 marker. These double-positive cells (probably inflammatory monocytes) markedly increased at day 6. The percentage of F4/80-GR1(+)cells (probably neutrophils) was low and did not significantly vary during tumor progression. CD4(+) and CD8(+) cells were not detected in the time points analyzed. iNOS and COX1 expression increased after day 2 reaching peak levels on day 10. COX2 enzyme expression did not change significantly over time. Sustained increase in PGE2 and NO levels was observed. IL-10 and MCP-1 peaked at day 14 and IL-1β increased progressively till day 10. IFN-γ levels were low till day 10, increasing progressively after that.

DISCUSSION

These data extended the characterization of the inflammatory response during Ehrlich ascitis tumor growth, further validating it as a useful model for antitumor drugs screening.

Melatonin suppresses proinflammatory mediators in lipopolysaccharide-stimulated CRL1999 cells via targeting MAPK, NF-κB, c/EBPβ, and p300 signaling

Melatonin is an indoleamine secreted by the pineal gland as well as a plant-derived product that exerts potential anti-inflammatory properties, but the mechanisms of action remain unclear. Here, we investigated the roles of melatonin in regulation of proinflammatory mediators and identified the underlying mechanisms in human vascular smooth muscle (VSM) cell line CRL1999 stimulated by lipopolysaccharide (LPS). We found that treatment with melatonin significantly inhibited the production and expression of TNF-α and interleukin (IL)-1β, cyclooxygenase-2 (COX-2), inducible nitric oxide synthase, prostaglandin E(2) (PGE2), and nitric oxide (NO) in a dose-dependent manner. Moreover, we also found that the suppression of proinflammatory mediators by melatonin was mediated through inhibition of MAPK, NF-κB, c/EBPβ, and p300 signaling in LPS-stimulated CRL1999 cells. Treatment with melatonin markedly inhibited phosphorylation of ERK1/2, JNK, p38 MAPK, IκB-α, and c/EBPβ, blocked binding of NF-κB and c/EBPβ to promoters, and suppressed p300 histone acetyltransferase (HAT) activity and p300 HAT-mediated NF-κB acetylation. Transfection with an ERK-, IκB-, or c/EBPβ-specific siRNA or pretreatment with an ERK-, p38 MAPK-, or p300-selective inhibitor considerably abrogated the melatonin-mediated inhibition of proinflammatory mediators. Conversely, exogenous overexpression of a constitutively active p300, but not its HAT mutant, effectively reversed the melatonin-mediated inhibitions. Collectively, these results indicate that melatonin suppresses proinflammatory mediators by simultaneously targeting the multiple signaling such as ERK/p38 MAPK, c/EBPβ, NF-κB, and p300, in LPS-stimulated VSM cell line CRL1999, and suggest that melatonin is a potential candidate compound for the treatment of proinflammatory disorders.

Puerarin inhibits iNOS, COX-2 and CRP expression via suppression of NF-κB activation in LPS-induced RAW264.7 macrophage cells

Puerarin (7,4'-dihydroxy-8-C-glucosylisoflavone) is the most abundant isoflavone-C-glucoside extracted from Radix puerariae, and it has been used for various medicinal purposes in traditional oriental medicine for thousands of years. In the present study, the ability of the puerarin to modulate inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and C reactive protein (CRP) expression and induce changes in the nuclear factor κB (NF-κB) pathway in RAW264.7 macrophage cells was examined. The protein and mRNA levels of lipopolysaccharide (LPS)-induced iNOS, COX-2 and CRP were determined in RAW246.7 macrophage cells. Inhibitor κB (I-κB) phosphorylation and p65NF-κB expression in RAW246.7 macrophage cells were also detected under our experimental conditions. The results indicated that puerarin inhibited the expression of LPS-induced iNOS, COX-2 and CRP proteins and also suppressed their mRNAs from RT-PCR experiments in RAW264.7 cells. Subsequently, we determined that the inhibition of iNOS, COX-2 and CRP expression was due to a dose-dependent inhibition of phosphorylation and degradation of I-κB, which resulted in the reduction of p65NF-κB nuclear translocation. These data suggested that the effect of puerarin-mediated inhibition of LPS-induced iNOS, COX-2 and CRP expression is attributed to suppressed NF-κB activation at the transcriptional level.

Exogenous mammalian extracellular HSP70 reduces endotoxin manifestations at the cellular and organism levels

In this study, we checked whether HSP70 preparations of different origins are able to protect model animals (rats) from endotoxic shock and modify the response of myeloid cells to lipopolysaccharide (LPS) challenge. It was shown that HSP70 preparations can effectively protect organisms from endotoxic shock by strongly decreasing mortality and restoring both homeostasis and various hemodynamic characteristics. At the cellular level, HSP70 preparations significantly inhibit LPS-induced reactive oxygen species production in various myeloid cells and decrease NO expression in macrophages, which is enhanced after LPS priming. In parallel, HSP70 preconditioning partially normalizes neutrophil apoptosis, which is disturbed as a result of LPS stimulation. These results suggest that the antiseptic actions of HSP70 preparations are probably realized at the level of receptor membrane complexes of myeloid cells, which represent the major target of LPS action. Taken together, our findings show that extracellular mammalian HSP70 may play an important role in innate immunity modulation and stimulation of endogenous protective mechanisms, both at the cellular and organism levels, which make this protein a promising base for the development of efficient antiseptic drugs.

Modulation of stress genes expression profile by nitric oxide-releasing aspirin in Jurkat T leukemia cells

NO-donating aspirin (NO-ASA, para isomer) has been reported to exhibit strong growth inhibitory effect in Jurkat T-acute lymphoblastic leukemia (T-ALL) cells mediated in part by beta-catenin degradation and caspase activation, but the mechanism(s) still remains unclear. In this study, DNA oligoarrays with 263 genes were used to examine the gene expression profiles relating to stress and drug metabolism, and characterize the stress responses at IC(50) and subIC(50) concentrations of p-NO-ASA (20 and 10microM, respectively) in Jurkat T cells. A total of 22 genes related to heat shock response, apoptosis signaling, detoxifiers and Phase II enzymes, and regulators of cell growth were altered in expression by array analysis based on the expression fold change criteria of > or =1.5-fold or < or =0.65-fold. Real time quantitative RT-PCR confirmed that 20microM p-NO-ASA strongly upregulated the mRNA levels of two heat shock genes HSPA1A (41.5+/-7.01-fold) and HSPA6 (100.4+/-8.11-fold), and FOS (16.2+/-3.2-fold), moderately upregulated HSPH1 (1.71+/-0.43-fold), FMO4 (4.5+/-1.67-fold), CASP9 (1.77+/-0.03-fold), DDIT3 (5.6+/-0.51-fold), and downregulated NF-kappaB1 (0.54+/-0.01-fold) and CCND1 (0.69+/-0.06-fold). Protein levels of Hsp70, the product of HSPA1A, and fos were increased in p-NO-ASA-treated Jurkat T and HT-29 colon cancer cells in a dose-dependent manner. Silencing of Hsp70 enhanced the growth inhibitory effect of p-NO-ASA at low concentrations. The altered gene expression patterns by NO-ASA in Jurkat T cells suggest mechanisms for carcinogen metabolism, anti-proliferative activity and possible chemoprotective activity in T-ALL.