Time dependent production of cytokines and eicosanoids by human monocytic leukaemia U937 cells; effects of glucocorticosteroids

Effects of Vitex trifolia L. leaf extracts and phytoconstituents on cytokine production in human U937 macrophages

Background

Dysregulation of pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) form the basis of immune-mediated inflammatory diseases. Vitex trifolia L. is a medicinal plant growing in countries such as China, India, Australia and Singapore. Its dried ripe fruits are documented in Traditional Chinese Medicine to treat ailments like rhinitis and dizziness. Its leaves are used traditionally to treat inflammation-related conditions like rheumatic pain.

Objective

This study aimed to investigate the effects of V. trifolia leaf extracts prepared by different extraction methods (Soxhlet, ultrasonication, and maceration) in various solvents on cytokine production in human U937 macrophages, and identify phytoconstituents from the most active leaf extract.

Methods

Fresh leaves of V. trifolia were extracted using Soxhlet, ultrasonication, and maceration in hexane, dichloromethane, methanol, ethanol or water. Each extract was evaluated for its effects on TNF-α and IL-1β cytokine production by enzyme-linked immunosorbent assay in lipopolysaccharide-stimulated human U937 macrophages. The most active extract was analyzed and further purified by different chemical and spectroscopic techniques.

Results

Amongst 14 different leaf extracts investigated, extracts prepared by ultrasonication in dichloromethane and maceration in ethanol were most active in inhibiting TNF-α and IL-1β production in human U937 macrophages. Further purification led to the isolation of artemetin, casticin, vitexilactone and maslinic acid, and their effects on TNF-α and IL-1β production were evaluated. We report for the first time that artemetin suppressed TNF-α and IL-1β production. Gas chromatography-mass spectrometry analyses revealed the presence of eight other compounds. To the best of our knowledge, this is the first report of butylated hydroxytoluene, 2,4-di-tert-butylphenol, campesterol and maslinic acid in V. trifolia leaf extracts.

Conclusions

In conclusion, leaf extracts of V. trifolia obtained using different solvents and extraction methods were successfully investigated for their effects on cytokine production in human U937 macrophages. The findings provide scientific evidence for the traditional use of V. trifolia leaves (a sustainable resource) and highlight the importance of conservation of medicinal plants as resources for drug discovery. Our results together with others suggest further investigation on V. trifolia and constituents to develop novel treatment strategies in immune-mediated inflammatory conditions is warranted.

Multiplexed, Sequential Secretion Analysis of the Same Single Cells Reveals Distinct Effector Response Dynamics Dependent on the Initial Basal State

The effector response of immune cells dictated by an array of secreted proteins is a highly dynamic process, requiring sequential measurement of all relevant proteins from single cells. Herein, a microchip-based, 10-plexed, sequential secretion assay on the same single cells and at the scale of ≈5000 single cells measured simultaneously over 4 time points are shown. It is applied to investigating the time course of single human macrophage response to toll-like receptor 4 (TLR4) ligand lipopolysaccharide (LPS) and reveals four distinct activation modes for different proteins in single cells. Protein secretion dynamics classifies the cells into two major activation states dependent on the basal state of each cell. Single-cell RNA sequencing performed on the same samples at the matched time points further demonstrates the existence of two major activation states at the transcriptional level, which are enriched for translation versus inflammatory programs, respectively. These results show a cell-intrinsic heterogeneous response in a phenotypically homogeneous cell population. This work demonstrates the longitudinal tracking of protein secretion signature in thousands of single cells at multiple time points, providing dynamic information to better understand how individual immune cells react to pathogenic challenges over time and how they together constitute a population response.

Modulation of proinflammatory cytokines and enzymes by polyherbal formulation Guggulutiktaka ghritam

BACKGROUND

Guggulutiktaka ghritam is an ayurvedic medicine which has been traditionally used to treat various chronic inflammatory conditions. However, the mechanism of action of the Ayurvedic medication in control of inflammatory conditions has not been clearly evaluated.

OBJECTIVE

In the current study, the effect of the Guggulutiktaka ghritam extract (GTG) on the lipoxygenase pathway and in the production of proinflammatory cytokines involved in the pathogenesis of chronic inflammation was studied.

MATERIALS AND METHODS

The effect of GTG in the production of leukotriene was determined by enzyme inhibition studies on 12- lipoxygenase. The assay was carried out by ferrous oxidation of xylenol orange (FOX assay) and was compared to a positive control nordihydroguaiaretic acid. The effect of GTG on the production of proinflammatory cytokines TNF-α and IL-1β in monocytes were studied. For this, the monocytes were pretreated with various concentrations of GTG and subsequently stimulated with lipopolysaccharide. The cytokines TNF-α and IL-1β produced were quantified by ELISA and the results were compared to positive controls Rolipram and Dexamethasone respectively. The gene expression studies were carried out using qRT-PCR. The IC₅₀ values were calculated and evaluated statistically.

RESULTS

The result indicates that GTG in comparison to the positive control Nordihydroguaiaretic acid significantly reduced the activity of 12- lipoxygenase. Also, there was significant inhibition in the production of proinflammatory cytokines in LPS stimulated monocytes pretreated with GTG as compared to positive control Rolipram and Dexamethasone. There was significant downregulation of IL-1β gene in LPS stimulated monocytes pretreated with GTG as compared to control. These changes are further supported by Raman spectra obtained for GTG treated and untreated cells.

CONCLUSION

The study revealed that GTG is a leukotriene and cytokine inhibitor. The inhibition in the production of cytokines may be due to the down-regulation of genes for TNF-α and IL-1β. The study provides a scientific validation on the possible anti-inflammatory mechanism of action of this traditionally used medicine. Identification of bioactive molecules would aid in developing newer therapeutics for control of chronic inflammation.

Systemic Inflammation Induced by microRNAs: Endometriosis-Derived Alterations in Circulating microRNA 125b-5p and Let-7b-5p Regulate Macrophage Cytokine Production

CONTEXT

Endometriosis is characterized by aberrant inflammation. We previously reported increased levels of microRNA (miRNA) 125b-5p and decreased levels of miRNA Let-7b-5p in serum of patients with endometriosis.

OBJECTIVE

Determine the regulatory function of miRNAs 125b-5p and Let-7b-5p on production of proinflammatory cytokines in endometriosis.

DESIGN

Case-control study.

SETTING

University hospital.

PATIENTS

Women with (20) and without (26) endometriosis; human U937 macrophage cell line.

INTERVENTION

Sera were collected from surgically diagnosed patients and differentiated U937 cells that were transfected with miRNAs 125b-5p and Let-7b-5p mimics and inhibitor.

MAIN OUTCOME MEASURES

Enzyme-linked immunosorbent assay for tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-8, and IL-1β levels and quantitative real-time polymerase chain reaction for expression of miRNAs 125b-5p and Let-7b-5p in sera of patients with and without endometriosis. Transfected macrophages were evaluated for expression of inflammatory cytokines, intracellular production, and secretion of these cytokines.

RESULTS

We noted substantial elevation of TNF-α, IL-1β, and IL-6, marked upregulation of miRNA 125b, and considerable downregulation of Let-7b in sera of patients with endometriosis vs control. There was a positive correlation between miRNA 125b levels and TNF-α, IL-1β, and IL-6 and a negative correlation between miRNA Let-7b levels and TNF-α in sera of patients with endometriosis. Transfection experiments showed a noteworthy upregulation of TNF-α, IL-1β, IL-6, and IL-8 in macrophages transfected with miRNA 125b mimic or Let-7b inhibitor. The secreted cytokine protein levels and intracellular imaging studies closely correlate with the messenger RNA changes.

CONCLUSIONS

Endometriosis-derived miRNAs regulate macrophage cytokine production that contributes to inflammation associated with this condition.

Triterpenoids from Ocimum labiatum Activates Latent HIV-1 Expression In Vitro: Potential for Use in Adjuvant Therapy

Latent HIV reservoirs in infected individuals prevent current treatment from eradicating infection. Treatment strategies against latency involve adjuvants for viral reactivation which exposes viral particles to antiretroviral drugs. In this study, the effect of novel triterpenoids isolated from Ocimum labiatum on HIV-1 expression was measured through HIV-1 p24 antigen capture in the U1 latency model of HIV-1 infection and in peripheral blood mononuclear cells (PBMCs) of infected patients on combination antiretroviral therapy (cART). The mechanism of viral reactivation was determined through the compound’s effect on cytokine production, histone deacetylase (HDAC) inhibition, and protein kinase C (PKC) activation. Cytotoxicity of the triterpenoids was determined using a tetrazolium dye and flow cytometry. The isolated triterpene isomers, 3-hydroxy-4,6a,6b,11,12,14b-hexamethyl-1,2,3,4,6,6a,6b,7,8,8a,9,10,11,12,12a,14,14a,14b-octadecahydropicene-4,8a-dicarboxylic acid (HHODC), significantly (p < 0.05) induced HIV-1 expression in a dose-dependent manner in U1 cells at non-cytotoxic concentrations. HHODC also induced viral expression in PBMCs of HIV-1 infected patients on cART. In addition, the compound up-regulated the production of interleukin (IL)-2, IL-6, tumour necrosis factor (TNF)-α, and interferon (IFN)-γ but had no effect on HDAC and PKC activity, suggesting cytokine upregulation as being involved in latency activation. The observed in vitro reactivation of HIV-1 introduces the adjuvant potential of HHODC for the first time here.

Synthesis, pharmacological activities and molecular docking studies of pyrazolyltriazoles as anti-bacterial and anti-inflammatory agents

A series of novel pyrazolyl alcohols (5a-h), pyrazolyl azides (6a-h), and pyrazolyltriazoles (8a-h, 10a-p and 12a-l) were prepared and evaluated for their bioactivity (anti-bacterial and anti-inflammatory) profile. The compound 5c displayed the potent anti-bacterial activity against Micrococcus luteus (MIC 3.9 and MBC 7.81µg/mL). In vitro anti-inflammatory activity data denoted that compound 8b is effective among the tested compounds against IL-6 (IC₅₀ 6.23μM). Docking analysis of compounds 5f, 8a-b, 8e-f and 8h displayed high binding energies for the compounds 8a-b and 8h towards TNF-α dimer (2AZ5 protein) and IL-6 (1ALU protein). In vivo anti-inflammatory activity of compounds 8b and 8h with respect to LPS induced mice model indicated that compound 8h showed significant reduction in TNF-α.

On-chip immune cell activation and subsequent time-resolved magnetic bead-based cytokine detection

Cytokine profiling and immunophenotyping offer great potential for understanding many disease mechanisms, personalized diagnosis, and immunotherapy. Here, we demonstrate a time-resolved detection of cytokine from a single cell cluster using an in situ magnetic immune assay. An array of triple-layered microfluidic chambers was fabricated to enable simultaneous cell culture under perfusion flow and detection of the induced cytokines at multiple time-points. Each culture chamber comprises three fluidic compartments which are dedicated to, cell culture, perfusion and immunoassay. The three compartments are separated by porous membranes, which allow the diffusion of fresh nutrient from the perfusion compartment into the cell culture compartment and cytokines secretion from the cell culture compartment into the immune assay compartment. This structure hence enables capturing the released cytokines without disturbing the cell culture and without minimizing benefit gain from perfusion. Functionalized magnetic beads were used as a solid phase carrier for cytokine capturing and quantification. The cytokines released from differential stimuli were quantified in situ in non-differentiated U937 monocytes and differentiated macrophages.

Ameloblastin Upregulates Inflammatory Response Through Induction of IL-1β in Human Macrophages

Ameloblastin (AMBN) is an enamel matrix protein that has various biological functions such as healing dental pulp and repairing bone fractures. In the present study, we clarified the effect of AMBN on the expression of an inflammatory cytokine, interleukin-1β (IL-1β) in lipopolysaccharide (LPS)-treated human macrophages. Real-time RT-PCR analysis showed that LPS treatment upregulated expression of the IL-1β gene in U937 cells. Interestingly, AMBN significantly enhanced IL-1β gene expression in LPS-treated U937 cells as well as the secretion of mature IL-1β into culture supernatants by these cells. AMBN also activated caspase-1 p10 expression in LPS-treated U937 cells. Pretreatment with a caspase-1 inhibitor, Z-YVAD-FMK, downregulated the mature IL-1β expression enhanced by AMBN treatment in LPS-treated U937 cells. A co-immunoprecipitation assay showed that treatment with LPS and AMBN upregulated toll-like receptor 4 (TLR4) and myeloid differentiation primary response gene 88 (MyD88) interactions, but there was no significant difference compared with LPS treatment alone in U937 cells. In contrast, western blot analysis revealed that AMBN remarkably prolonged the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), a member of the mitogen-activated protein kinase (MAPK) family. An ERK1/2-selective inhibitor, U0126, suppressed expression of the IL-1β gene as well as its protein expression in U937 cells treated with LPS and AMBN. Taken together, these results indicate that AMBN enhances IL-1β production in LPS-treated U937 cells through ERK1/2 phosphorylation and caspase-1 activation, suggesting that AMBN upregulates the inflammatory response in human macrophages and plays an important role in innate immunity. J. Cell. Biochem. 118: 3308-3317, 2017. © 2017 Wiley Periodicals, Inc.

Nuclear factor erythroid 2-related factor 2 is a critical target for the treatment of glucocorticoid-resistant lupus nephritis

Background

Dimethyl fumarate (DMF), a nuclear factor erythroid 2-related factor 2 (Nrf2) activator, has been proven effective for the systemic treatment of multiple sclerosis. The aim of this study is to evaluate the anti-inflammatory effects of Nrf2 activators on human renal mesangial cells (HRMCs) and the development of lupus nephritis (LN) in mice.

Methods

To assess Nrf2 activation in vitro, HRMCs were treated with safe doses of Nrf2 activators and prednisolone. The expression levels of Nrf2 and its target genes were measured using quantitative reverse transcription PCR and enzyme-linked immunosorbent assay. The anti-inflammatory effects of these compounds were assessed by measuring tumor necrosis factor alpha-induced cytokine secretion. Experimental LN was induced in female BALB/c mice by a single intraperitoneal injection of pristane. The urine albumin-to-creatinine ratio was measured at 20 weeks after injection. Pathological changes as well as protein and mRNA expression levels were assessed in the kidney obtained at the experimental end point. Oral administration of DMF or prednisolone to these mice was initiated after pristane injection.

Results

Nrf2 activators such as sulforaphane and DMF showed anti-inflammatory effects in HRMCs, whereas glucocorticoid (prednisolone) showed partial effects. Moreover, DMF ameliorated the development of kidney diseases in pristane-induced LN mice, whereas glucocorticoid had no effect.

Conclusions

Nrf2 activators showed stronger anti-inflammatory and organ-protective effects than glucocorticoid in the kidney. Thus, Nrf2 activators are potential therapeutic targets in glucocorticoid-resistant LN in humans.

Ethanol extract of Adiantum capillus-veneris L. suppresses the production of inflammatory mediators by inhibiting NF-κB activation

ETHNOPHARMACOLOGICAL RELEVANCE

Adiantum capillus-veneris L. is a wildly distributed plant species and has been extensively used in south of China as traditional folk medicine for the treatment of inflammatory diseases.

AIM OF THE STUDY

To investigate the anti-inflammatory effect of ethanolic extracts of Adiantum capillus-veneris L. and the involvement of NF-κB signaling in the regulation of inflammation.

MATERIALS AND METHODS

The plant ethanolic extracts were initially tested against lipopolysaccharide (LPS)-induced prostaglandin E2 (PGE2) production in RAW264.7 mouse macrophages, and interleukin 6 (IL-6) and tumor necrosis factor (TNF) production in human U937 monocytes. The effect of the plant extracts on the transcription factor nuclear factor kappa B (NF-κB) pathway was evaluated in TNF-α stimulated HepG2 cells by luciferase gene reporter assay and Western blotting at the transcriptional and translational levels. Subsequently, the inhibition of NF-κB downstream gene expression (IL-8 and ICAM-1) by the plant extracts was assessed via quantitative real time polymerase chain reaction (qPCR). Lastly, the anti-inflammatory activities of the plant extracts in vivo were evaluated by testing spleen index and NF-κB related protein expression in LPS-stimulated CD1 mice.

RESULTS

The plant ethanolic extracts effectively suppressed PGE2, IL-6 and TNF release with an IC50 less than 50 μg/ml. Moreover, luciferase expression could be specifically blocked in HepG2 cells, not in HEK293 cells, showing that the plant extracts displayed a cell-specific pattern on NF-κB gene transcription. The assayed biological activity also depended on the order of adding TNF-α and the plant extracts because the plant extracts could only block the NF-κB activation if added earlier but were unable to stop the signal when added after TNF-α. However, the plant extracts did not exert any effect on ubiquitination which regulates several steps in the NF-κB pathway. Additionally, the plant extracts down-regulated phosphorylation of IKKα/β at S176/180, p38 at T180/Y182 and p65 at S536, but not p65 at S276. This was confirmed by their ability to selectively abrogate the induction of IL-8 transcription, whereas the ICAM-1 gene, which is not transcribed selectively by an NF-κB complex containing a form of p65 phosphorylated on Ser536, did not change. Finally, the plant extracts at 200 μg/mg could normalize the LPS-induced elevation of spleen index as well as NF-κB and p38 activations in CD1 mice.

CONCLUSION

The present studies presents the potential utilization of this plant extracts, as a natural resources for the development of an anti-inflammatory medicine.

Contact sensitizers modulate the arachidonic acid metabolism of PMA-differentiated U-937 monocytic cells activated by LPS

For the effective induction of a hapten-specific T cell immune response toward contact sensitizers, in addition to covalent-modification of skin proteins, the redox and inflammatory statuses of activated dendritic cells are crucial. The aim of this study was to better understand how sensitizers modulate an inflammatory response through cytokines production and COX metabolism cascade. To address this purpose, we used the human monocytic-like U-937 cell line differentiated by phorbol myristate acetate (PMA) and investigated the effect of 6 contact sensitizers (DNCB, PPD, hydroquinone, propyl gallate, cinnamaldehyde and eugenol) and 3 non sensitizers (lactic acid, glycerol and tween 20) on the production of pro-inflammatory cytokines (IL-1β and TNF-α) and on the arachidonic acid metabolic profile after bacterial lipopolysaccharide (LPS) stimulation. Our results showed that among the tested molecules, all sensitizers specifically prevent the production of PMA/LPS-induced COX-2 metabolites (PGE(2,) TxB(2) and PGD(2)), eugenol and cinnamaldehyde inhibiting also the production of IL-1β and TNF-α. We further demonstrated that there is no unique PGE(2) inhibition mechanism: while the release of arachidonic acid (AA) from membrane phospholipids does not appear do be a target of modulation, COX-2 expression and/or COX-2 enzymatic activity are the major steps of prostaglandin synthesis that are inhibited by sensitizers. Altogether these results add a new insight into the multiple biochemical effects described for sensitizers.

The influence of hyperglycemia and other clinical variables on rehabilitation and hospital length of stay after neurosurgery in patients with cancer

OBJECTIVE

Our study was designed to address whether steroid-induced hyperglycemia after neurosurgery affects rehabilitation and hospital length of stay (LOS) in patients with cancer.

PATIENTS AND METHODS

We reviewed the medical records of 290 post-neurosurgery patients at our cancer center in 2002.

RESULTS

Of the 267 nondiabetic patients and 23 diabetic patients (P < .001), 2 and 8, respectively, had hyperglycemia which is defined as casual plasma glucose concentrations of ≥200 mg/dL on 2 different days. In all patients studied, hyperglycemia does not predict longer hospital stay or needs for rehabilitation.

CONCLUSIONS

The frequency of corticosteroid-induced hyperglycemia in post-neurosurgery patients with cancer was low.

Pharmacokinetics and anti-inflammatory pharmacodynamics of prednisolone in cynomolgus monkey

The purpose was to investigate whether the pharmacokinetics and pharmacodynamics of prednisolone in the non-human primate was an appropriate surrogate for man. After single intravenous doses of 0.03, 0.3, and 3 mg kg(-1), prednisolone demonstrated a dose-dependent clearance and volume of distribution. When corrected for concentration-dependent protein binding, the free clearance was linear at the tested dose levels. The protein binding-corrected volume of distribution was similar across doses. The serum half-life was estimated as being between 2 and 4 h. Prednisolone exhibits near complete inhibition of the cytokines TNF-alpha, IL-1beta, IL-6 and IL-8 with very similar IC50 estimates from 0.09 to 0.16 microg ml(-1) (from 0.24 to 0.44 microM). The monkey demonstrated a similar pharmacokinetics-pharmacodynamics profile of prednisolone when compared with man (from the literature).

Auto/paracrine control of inflammatory cytokines by acetylcholine in macrophage-like U937 cells through nicotinic receptors

Although acetylcholine (ACh) is well known for its neurotransmitter function, recent studies have indicated that it also functions as an immune cytokine that prevents macrophage activation through a 'cholinergic (nicotinic) anti-inflammatory pathway'. In this study, we used the macrophage-like U937 cells to elucidate the mechanisms of the physiologic control of cytokine production by auto/paracrine ACh through the nicotinic class of ACh receptors (nAChRs) expressed in these cells. Stimulation of cells with lipopolysaccharide up-regulated expression of alpha1, alpha4, alpha5, alpha7, alpha10, beta1 and beta3 subunits, down-regulated alpha6 and beta2 subunits, and did not alter the relative quantity of alpha9 and beta4 mRNAs. Distinct nAChR subtypes showed differential regulation of the production of pro- and anti-inflammatory cytokines. While inhibition of the expression of the TNF-alpha gene was mediated predominantly by the alpha-bungarotoxin sensitive nAChRs, that of the IL-6 and IL-18 genes-by the mecamylamine-sensitive nAChRs. Both the Mec- and alphaBtx-sensitive nAChRs regulated expression of the IL-1beta gene equally efficiently. Upregulation of IL-10 production by auto/paracrine ACh was mediated predominantly through alpha7 nAChR. These findings offer a new insight on how nicotinic agonists control inflammation, thus laying a groundwork for the development of novel immunomodulatory therapies based on the nAChR subtype selectivity of nicotinic agonists.

The effect of OTK18 upregulation in U937 cells on neuronal survival

The intent of this study was to characterize the effect OTK18 upregulation in monocytic cells had on neuronal survival. The human monocytic cell line, U937, was differentiated into macrophages or left as an undifferentiated monocyte. These cells were transfected with a plasmid containing the enhanced green fluorescent protein and OTK18 (pEGFP-OTK18) or an empty control vector (pEGFP-N3). The supernatants from the transfected U937 cells were used to culture rat neuronal cells (PC12). A live/dead assay was performed to determine the effect of culturing on cell survival. The protein levels of the neurotoxin, tumor necrosis factor alpha (TNF-alpha), and the neurotrophin, neurotrophin three (NT3), were determined by enzyme linked immunosorbent assay. The results of the live/dead assay showed differential cell survival between conditions with pEGFP-OTK18 when compared to the control empty vector. Quantitative real-time polymerase chain reaction assays demonstrated that OTK18 had an increased expression level when compared to the control. Lastly, NT3 protein levels were upregulated in treated cells with increased OTK18 expression, suggesting that OTK18 may play a role in neurotrophin production and consequently support neuronal survival.

Increased expression of FcgammaRI/CD64 on circulating monocytes parallels ongoing inflammation and nephritis in lupus

Introduction

The high-affinity receptor for IgG Fcγ/CD64 is critical for the development of lupus nephritis (LN). Cross-linking Fc receptor on recruited monocytes by IgG-containing immune complexes is a key step in immune-complex-mediated nephritis in systemic lupus erythematosus (SLE). The goal of this study was to determine whether expression of Fc receptor (FcγR) I on circulating monocytes is associated with systemic inflammation and renal disease in SLE patients.

Methods

We studied 205 SLE patients (132 with LN and 73 without LN) along with 74 healthy control individuals. Surface expression of CD14 (monocytes), FcγRI/CD64, FcγRII/CD32, and FcγRIII/CD16 was evaluated by flow cytometry. Monocyte function was assessed by determining the migratory capacity and the ability to produce CCL2 (monocyte chemotractic protein 1). High-sensitivity C-reactive protein, C3 and C4 were measured by nephelometry.

Results

There was little difference in the expression of FcγRIII/CD16 or FcγRIII/CD32 on circulating monocytes between patients with SLE and control individuals. In contrast, FcγRI/CD64 expression was significantly higher in SLE patients and even higher in patients with LN. FcγRI/CD64 expression was positively associated with serum creatinine and indicators of systemic inflammation. Monocytes from patients with high FcγRI/CD64 expression also exhibited increased chemotaxis and capacity to produce monocyte chemotractic protein 1.

Conclusions

Increased FcγRI/CD64 expression on circulating monocytes parallels systemic inflammation and renal disease in SLE patients. We propose that circulating monocytes activated by immune complexes and/or proinflammatory mediators upregulate surface expression of FcγRI/CD64 in SLE. The enhanced chemotactic and inflammatory potential of the activated monocytes may participate in a vicious cycle of immune cell recruitment and renal injury in SLE.

A proinflammatory cytokine interleukin-32beta promotes the production of an anti-inflammatory cytokine interleukin-10

A new proinflammatory cytokine interleukin-32 (IL-32) has six isoforms. Although IL-32 can be detected in sera from patients suffering from Crohn's disease and rheumatoid arthritis, it is unclear which isoforms are involved. To this end, we investigated the functions of the most abundant IL-32beta by generating K562-IL-32beta stable cell lines. This report confirms, using IL-32 small interfering RNA, that IL-32beta induces an anti-inflammatory cytokine IL-10 in K562-IL-32beta cells and U937 promonocytic cells, which express endogenous IL-32beta upon phorbol 12-myristate 13-acetate (PMA) treatment, and monocyte-derived dendritic cells (DC) upon lipopolysaccharide (LPS) treatment. Interleukin-32beta was induced in monocyte-derived macrophages by LPS and in monocyte-derived DC by LPS, poly(I:C), or anti-CD40 antibody, but was not induced by PMA. We showed that IL-32beta expression was increased in a time-dependent manner in monocyte-derived DC upon LPS treatment and peaked at 24 hr. Production of IL-10 was exactly coincident with IL-32beta expression, but IL-1beta and tumour necrosis factor-alpha production peaked at 6 hr after LPS treatment, then steeply declined. Interleukin-12 p40 was induced at 9 hr and gradually increased until 48 hr, at which time IL-32beta and IL-10 were no longer increased. Knock-down of IL-32beta by IL-32 small interfering RNA led to the decrease of IL-10, but the increase of IL-12 in monocyte-derived DC, which means that IL-32beta promotes IL-10 production, but limits IL-12 production. We also showed that IL-10 neutralization increases IL-12, IL-1beta and tumour necrosis factor-alpha production, which implies that IL-10 suppresses such proinflammatory cytokines. Taken together, our results suggest that IL-32beta upregulates the production of an anti-inflammatory cytokine IL-10, and then IL-10 suppresses proinflammatory cytokines.

Mononuclear cell-derived interleukin-1 beta confers chemoresistance in pancreatic cancer cells by upregulation of cyclooxygenase-2

BACKGROUND

Pancreatic cancer is a very aggressive malignancy and efficient therapeutic options are still largely lacking. The importance of interactions between tumor cells and surrounding stromal elements, eg, mononuclear cells, for chemoresistance have been increasingly recognized. In addition, cyclooxygenase-2 is thought to be an important mediator of chemoresistance in several malignancies. The aim of this study was to explore the role of mononuclear cells in pancreatic cancer chemoresistance.

METHODS

Human histiocytic lymphoma U937 cells were differentiated into macrophage-like cells. The effect of U937-conditioned medium on drug-induced pancreatic cancer cell apoptosis was measured by enzyme-linked immunosorbent assay. The contributions of interleukin-1beta and cyclooxygenase-2 were evaluated by specific receptor antagonists and inhibitors. The importance of the extracellular signal-regulated kinase (ERK1/2) pathway also was determined.

RESULTS

U937-conditioned culture medium protected pancreatic cancer cells from drug-induced apoptosis. This protective effect was abolished by an interleukin-1 receptor antagonist and cyclooxygenase-2 inhibitor. U937-conditioned medium and interleukin-1beta stimulated expression of cyclooxygenase-2 and prostaglandin E(2) production in pancreatic cancer cells, which was mediated by activation of the ERK1/2 pathway. Transfection of pancreatic cancer cells with cyclooxygenase-2 increased resistance to drug-induced cell death.

CONCLUSIONS

Mononuclear cells protect pancreatic cancer cells from drug-induced apoptosis in vitro by interleukin-1beta-mediated expression of cyclooxygenase-2 and production of prostaglandins. This study highlights the importance of tumor-host interactions in pancreatic cancers and may provide the basis for novel therapeutic approaches to sensitize pancreatic cancers to chemotherapeutic agents.

Steroid-induced diabetes mellitus and related risk factors in patients with neurologic diseases

STUDY OBJECTIVE

To determine the frequency of steroid-induced diabetes mellitus (SDM) and the related risk factors in patients with neurologic diseases who receive high doses of steroids.

DESIGN

Retrospective chart review.

SETTING

Neurology ward of a university-affiliated hospital.

PATIENTS

Twenty-five patients with neurologic diseases who received prednisolone 30-60 mg/day orally after breakfast for more than 2 weeks.

MEASUREMENTS AND MAIN RESULTS

Plasma glucose concentrations were determined immediately before and 2 hours after each meal. Steroid-induced diabetes mellitus was diagnosed if the patient had either a fasting glucose concentration of 126 mg/dl or greater, or a random glucose concentration of 200 mg/dl or greater. The patients were divided into two groups on the basis of whether SDM had developed (13 patients) or not (12 patients). Ages, body mass indexes, cumulative total doses and daily doses of prednisolone, duration of therapy, and serum cholesterol and triglyceride concentrations were compared between the groups. Thirteen of the 25 patients were identified with SDM, and all of them had plasma glucose concentrations of 200 mg/dl or greater 2 hours after lunch. Mean age (59.1 +/- 10.2 yrs) and cholesterol concentration after prednisolone treatment (226.8 +/- 36.4 mg/dl) in the SDM group were significantly higher than those values in the non-SDM group (41.3 +/- 18.0 yrs and 188.1 +/- 27.2 mg/dl, respectively, p<0.01).

CONCLUSIONS

A close relationship among postprandial hyperglycemia, advanced age, and hypercholesterolemia is a characteristic of SDM in patients with neurologic diseases. Therefore, monitoring the plasma glucose concentration 2 hours after lunch may be useful to detect SDM in these patients.

PCT-233, a novel modulator of pro- and anti-inflammatory cytokine production

Plant extracts have been implicated in various immunoregulatory effects that are poorly understood. Thus, we investigated the modulatory activity of PureCell Complex (PCT)-233, an active molecular complex from mesophyll tissue of Spinacia oleacea on the inflammatory process. Alveolar macrophages (AM) were treated with PCT-233 and/or budesonide, a well-known anti-inflammatory agent, before or after being stimulated with lipopolysaccharides (LPS). Pro- and anti-inflammatory cytokine production, tumour necrosis factor (TNF) and interleukin (IL)-10, respectively, were measured in cell-free supernatants at different times after the treatment. PCT-233 increased unstimulated AM release of both TNF and IL-10, whereas heat- and light-inactivated PCT-233 stimulated only the release of TNF without affecting IL-10 production, suggesting that different mechanisms are involved in the modulation of TNF and IL-10 release by PCT-233. The presence of LPS did not modify PCT-233-stimulated TNF production, but the ratio TNF/IL-10 production by LPS-stimulated AM was reduced significantly in the presence of PCT-233. Pretreatment of AM with PCT-233 and budesonide before LPS stimulation reduced TNF production at both protein and mRNA levels, whereas IL-10 production was increased. Moreover, TNF/IL-10 ratio was reduced further with the combination PCT-233/budesonide. Interestingly, AM treatment with PCT-233 and budesonide 18 h after LPS stimulation did not modulate TNF release significantly but it did increase IL-10 production, and a synergistic effect was observed with the combination PCT-233/budesonide. These exciting data suggest that PCT-233 possesses some anti-inflammatory properties, even when added during the inflammatory process, and could potentiate the effect of other anti-inflammatory agents.

Induction of cytokine mRNA expression in U937 cells by Salmonella typhimurium porins is regulated by different phosphorylation pathways

Lipopolysaccharide (LPS) and porins of Gram-negative outer membranes are the main pathogenic factors implicated in the clinical syndrome of septic shock. The biological activity of porins and LPS are similar, but they occur by different mechanisms. It seems that porins act through different intracellular pathways with respect to LPS. In this study we analyzed the role of several inhibitors of the MEK/ERK signal pathway on the induction of proinflammatory and immunological cytokines in U937 cell line stimulated by Salmonella typhimurium porins and compared it to the cytokine induction after LPS stimulation. We investigated the effects of p38 MAP kinase inhibitor SB-203580, MEK/ERK kinase inhibitor PD-098059 and Raf-1 inhibitor forskolin, and demonstrated that they modulate cytokine mRNA expression in a different manner as a consequence of the use of porins or LPS as stimuli. TNF-alpha and IL-1beta mRNA expression is decreased by PD-098059 after stimulation with LPS but not with porins in differentiated U937 cells. IL-10 mRNA expression is inhibited by SB-203580 and PD-098059 after stimulation with porins in U937 cells. IL-6 and IL-8 mRNA expression is not changed by PD-098059 or SB-203580, after stimulation either with porins or LPS. Furthermore, mRNA expression of the studied cytokines, except for GM-CSF, is not changed using forskolin.

A randomized, double-blind trial of the effect of glucocorticoid, antileukotriene and beta-agonist treatment on IL-10 serum levels in children with asthma

BACKGROUND

Levels of an immunoregulatory and anti-inflammatory cytokine IL-10 are reduced in asthmatic airways, potentially contributing to more intense inflammation. Triamcinolone has anti-inflammatory properties and the anti-inflammatory effects of montelukast and formoterol have been discussed.

OBJECTIVE

The purpose of this study was to define the effect of treatment with triamcinolone, montelukast and formoterol on the serum level of IL-10, eosinophil blood counts, eosinophil cationic response (ECP) and clinical parameters (symptom score, FEV1 and PC20H) in children with moderate asthma.

METHODS

An 8-week, placebo-controlled and randomized, double-blind trial was carried out. The subjects were 91 children with moderate atopic asthma who were allergic to dust mite. Patients were randomly allocated to receive 400 microg triamcinolone (n = 19), 5 or 10 mg (according to age) montelukast (n = 18), 24 microg formoterol (n = 18) or placebo (n = 36).

RESULTS

Seventy-nine children completed the study. After treatment with triamcinolone and montelukast the level of IL-10 in blood serum significantly increased, eosinophil blood counts and ECP levels significantly decreased and all clinical parameters improved; treatment with formoterol had no effect on IL-10 level, eosinophil blood counts in serum and bronchial hyper-reactivity; ECP level significantly decreased after treatment and asthma symptoms and FEV1 improved significantly. Mean IL-10 levels in serum before and after treatment with triamcinolone were 7.23 pg/mL with 95% CI, 6.74 -7.72% and 14.24 pg/mL with 95% CI, 11.6-16.88%, respectively (P < 0.001); with montelukast they were 6.59 pg/mL with 95% CI, 6.26-7.23% and 10.94 pg/mL with 95% CI, 8.24-12.65%, respectively (P < 0.002); with formoterol they were 7.06 pg/mL with 95% CI, 6.61-7.52% and 7.04 pg/mL with 95% CI, 6.15-7.93%. We found statistically significant correlations between serum level of IL-10 and serum level of ECP after treatment with triamcinolone and montelukast.

CONCLUSION

This study demonstrates that one possible way by which triamcinolone and montelukast contribute to inhibition of inflammation is by increasing IL-10 levels.

Locally and systemically active glucocorticosteroids modify intestinal absorption of lipids in rats

Orally administered systemically active steroids enhance the digestive and absorptive functions of the intestine, but their effect on lipid uptake is unknown. The effect of the locally acting steroid budesonide on intestinal absorptive function also is unknown. Accordingly, this study was undertaken to assess the influence of 4 wk of treatment of weaning male rats with a daily oral gavage of budesonide (BUD), prednisone (PRED), or control vehicle on the jejunal and ileal uptake of fatty acids and cholesterol. BUD enhanced jejunal uptake of oleic acid and ileal uptake of linoleic acid. PRED increased jejunal uptake of cholesterol and ileal uptake of lauric, palmitic, linoleic, and linolenic acids. Higher doses of BUD (up to 1 mg/kg) given to adult rats for 2 wk further increased the uptake of some lipids. The changes in the uptake of lipids were not due to variations in the weight of the intestinal mucosa or in the animals' food intake. Ileal ornithine decarboxylase mRNA expression was increased with PRED, but there were no steroid-associated changes in the expression of the mRNA of the early response genes c-myc, c-jun, or c-fos or of proglucagon, the liver fatty acid-binding protein (FABP), the ileal lipid-binding protein, tumor necrosis factor alpha, interleukin 2 (IL-2), IL-6, or IL-10. In summary, treatment of weanling rats with BUD and PRED enhances the uptake of some lipids by a process that is independent of the effects of early response genes and genes encoding cytokines, proglucagon, and FABP.

Neuroimmune alterations in the complex regional pain syndrome

This review focuses on some clinical aspects of the complex regional pain syndrome, such as oedema, local temperature changes and chronic pain, as a result of supposed neurogenic inflammation. Involvement of the immune system could imply the subsequent release of neuropeptides, pro-inflammatory cytokines and eicosanoids, which in turn leads to a complex cross-talk of primary and secondary generated mediators of inflammation. The development and application of drugs that act through selective receptor antagonism or enzymatic synthesis inhibition to prevent further stimulation of this cascade that could inevitably lead to chronicity of this disease are extensively discussed.

Transcription factor-mediated molecular mechanisms involved in the functional cross-talk between cytokines and glucocorticoids

After antigenic stimulation the increase in cytokine levels constitutes a fundamental event in the host defense and mediates many processes such as inflammation, B- and T-cell growth and differentiation and activation of effector cells. Most of these processes depend on the cytokine-induced activation of transcription factors that modulate the expression of target genes. Cytokines induce a rise in glucocorticoid levels, which are instrumental in controlling immune-cytokine overreactions. Because of their anti-inflammatory and immunosuppressive actions, glucocorticoids are highly useful as therapeutic drugs in a range of diseases. The cross-talk between cytokine-induced transcription factors such as nuclear factor-kappaB, activating protein-1, cAMP responsive element binding protein and nuclear factor of activated T cells, and glucocorticoid receptors involves both genomic and non-genomic actions, and constitutes the mechanism by which glucocorticoid repressive effects on cytokine synthesis and action take place. These molecular interactions represent the key for the study of physiological compensatory actions of corticosteroids, the interactions of cytokines and glucocorticoids at their target cells, as well as the therapeutic benefits and side-effects of synthetic steroids. For this reason, we will focus on the molecular aspects of cytokine-glucocorticoid interactions, represented by the cross-coupling between cytokine-mediated transcription factors and glucocorticoid receptors.