The anti‐seizure drugs vinpocetine and carbamazepine,but not valproic acid,reduce inflammatory IL‐1β and TNF‐α expression in rat hippocampus

In the present study, the effects of the two classical anti‐epileptic drugs, carbamazepine and valproic acid, and the non‐classical anti‐seizure drug vinpocetine were investigated on the expression of the pro‐inflammatory cytokines IL‐1β and TNF‐α in the hippocampus of rats by PCR or western blot after the administration of one or seven doses. Next, the effects of the anti‐seizure drugs were investigated on the rise in cytokine expression induced by lipopolysaccharides (LPS) inoculation in vivo. To validate our methods, the changes induced by the pro‐convulsive agents 4‐aminopyridine, pentylenetetrazole and pilocarpine were also tested. Finally, the effect of the anti‐seizure drugs on seizures and on the concomitant rise in pro‐inflammatory cytokine expression induced by 4‐aminopyridine was explored. Results show that vinpocetine and carbamazepine reduced the expression of IL‐1β and TNF‐α from basal conditions, and the increase in both pro‐inflammatory cytokines induced by LPS. In contrast, valproic acid failed to reduce both the expression of the cytokines from basal conditions and the rise in IL‐1β and TNF‐α expression induced by LPS. Tonic‐clonic seizures induced either by 4‐aminopyridine, pentylenetetrazole or pilocarpine increased the expression of IL‐1β and TNF‐α markedly. 4‐aminopyridine‐induced changes were reduced by all the tested anti‐seizure drugs, although valproic acid was less effective. We conclude that the anti‐seizure drugs, vinpocetine and carbamazepine, whose mechanisms of action involve a decrease in ion channels permeability, also reduce cerebral inflammation.

     

Anti‐inflammatory effects of melatonin in a rat model of caerulein‐induced acute pancreatitis

The purpose of our study was to evaluate the protective effect of melatonin in a rat model of caerulein‐induced acute pancreatitis. For the induction of experimental acute pancreatitis, four subcutaneous injections of caerulein (20 µg kg^–1 body weight) were given to Wistar rats at 2‐h intervals. Melatonin was injected intraperitoneally (25 mg kg^–1 body weight) 30 min before each caerulein injection. After 12 h, rats were sacrificed by decapitation. Blood and pancreas samples were collected and processed for serological and histopathological studies, respectively. Lipase, α‐amylase, corticosterone, total antioxidant power and cytokines interleukin (IL)‐1β, IL‐4 and tumour necrosis factor (TNF)‐α were determined using commercial kits. ANOVA and Tukey tests (P < 0.05) were performed for the statistical analysis of the results. Results showed that the administration of melatonin reduced histological damage induced by caerulein treatment as well as the hyperamylasemia and hyperlipidemia. Corticosterone and antioxidant total power were also reverted to basal activities. Furthermore, melatonin pre‐treatment reduced pro‐inflammatory cytokines IL‐1β and TNF‐α and increased the serum levels of anti‐inflammatory cytokine IL‐4. In conclusion, the findings suggest that the protective effect of melatonin in caerulein‐induced acute pancreatitis is mediated by the anti‐inflammatory ability of this indolamine. Thus, melatonin may have a protective effect against acute pancreatitis. Copyright © 2013 John Wiley & Sons, Ltd.     

Plasma levels of soluble ST2, but not IL‐33, correlate with the severity of alcoholic liver disease

Alcoholic liver disease (ALD) is a complication that is a burden on global health and economy. Interleukin‐33 (IL‐33) is a newly identified member of the IL‐1 cytokine family and is released as an “alarmin” during inflammation. Soluble suppression of tumourigenicity 2 (sST2), an IL‐33 decoy receptor, has been reported as a new biomarker for the severity of systemic and highly inflammatory diseases. Here, we found the levels of plasma sST2, increased with the disease severity from mild to severe ALD. Importantly, the plasma sST2 levels in ALD patients not only correlated with scores for prognostic models (Maddrey's discriminant function, model for end‐stage liver disease and Child‐Pugh scores) and indexes for liver function (total bilirubin, international normalized ratio, albumin, and cholinesterase) but also correlated with neutrophil‐associated factors as well as some proinflammatory cytokines. In vitro, lipopolysaccharide‐activated monocytes down‐regulated transmembrane ST2 receptor but up‐regulated sST2 mRNA and protein expression and produced higher levels of tumour necrosis factor‐α (TNF‐α). By contrast, monocytes pretreated with recombinant sST2 showed decreased TNF‐α production. In addition, although plasma IL‐33 levels were comparable between healthy controls and ALD patients, we found the IL‐33 expression in liver tissues from ALD patients was down‐regulated at both RNA and protein levels. Immunohistochemical staining further showed that the decreased of IL‐33‐positive cells were mainly located in liver lobule area. These results suggested that sST2, but not IL‐33, is closely related to the severity of ALD. Consequently, sST2 could be used as a potential biomarker for predicting the prognosis of ALD.     

Chronic exercise decreases cytokine production in healthy rat skeletal muscle

Skeletal muscle is the source of pro‐ and anti‐inflammatory cytokines, and recently, it has been recognized as an important source of interleukin‐6 (IL‐6). Acute physical exercise is known to induce a pro‐inflammatory cytokine profile in the plasma. However, the effect of chronic physical exercise in the production of pro‐ and anti‐inflammatory cytokines by the skeletal muscle has never been examined. We assessed IL‐6, TNF‐α, IL‐1β and IL‐10 levels in the skeletal muscle of rats submitted to endurance training. Animals were randomly assigned to either a sedentary group (S, n = 7) or an endurance exercise trained group (T, n = 8). Trained rats ran on a treadmill for 5 days week^?1 for 8 weeks (60% VO_2max). Detection of IL‐6, TNF‐α, IL‐1β and IL‐10 protein expression was carried out by ELISA. We found decreased expression of IL‐1β, IL‐6, TNF‐α and IL‐10 (28%, 27%, 32% and 37%, respectively, p < 0.05) in the extensor digital longus (EDL) from T, when compared with S. In the soleus, IL‐1β, TNF‐α and IL‐10 protein levels were similarly decreased (34%, 42% and 50%, respectively, p < 0.05) in T in relation to S, while IL‐6 expression was not affected by the training protocol. In conclusion, exercise training induced decreased cytokine protein expression in the skeletal muscle. These data show that in healthy rats, 8‐week moderate‐intensity aerobic training down regulates skeletal muscle production of cytokines involved in the onset, maintenance and regulation of inflammation, and that the response is heterogeneous according to fibre composition. Copyright © 2009 John Wiley & Sons, Ltd.     

Antimicrobial and anti‐inflammatory activity of five Taxandria fragrans oils in vitro

The antimicrobial activity of five samples of Taxandria fragrans essential oil was evaluated against a range of Gram‐positive (n= 26) and Gram‐negative bacteria (n= 39) and yeasts (n= 10). The majority of organisms were inhibited and/or killed at concentrations ranging from 0.06–4.0% v/v. Geometric means of MIC were lowest for oil Z (0.77% v/v), followed by oils X (0.86%), C (1.12%), A (1.23%) and B (1.24%). Despite differences in susceptibility data between oils, oils A and X did not differ when tested at 2% v/v in a time kill assay against Staphylococcus aureus. Cytotoxicity assays using peripheral blood mononuclear cells demonstrated that T. fragrans oil was cytotoxic at 0.004% v/v but not at 0.002%. Exposure to one or more of the oils at concentrations of ≤0.002% v/v resulted in a dose responsive reduction in the production of proinflammatory cytokines IL‐6 and TNF‐α, regulatory cytokine IL‐10, Th1 cytokine IFN‐γ and Th2 cytokines IL‐5 and IL‐13 by PHA stimulated mononuclear cells. Oil B inhibited the production of all cytokines except IL‐10, oil X inhibited TNF‐α, IL‐6 and IL‐10, oil A inhibited TNF‐α and IL‐6, oil C inhibited IL‐5 and IL‐6 and oil Z inhibited IL‐13 only. IL‐6 production was significantly inhibited by the most oils (A, B, C and X), followed by TNF‐α (oils A, B and X). In conclusion, T. fragrans oil showed both antimicrobial and anti‐inflammatory activity in vitro, however, the clinical relevance of this remains to be determined.     

Natural antiviral compound silvestrol modulates human monocyte‐derived macrophages and dendritic cells

Outbreaks of infections with viruses like Sars‐CoV‐2, Ebola virus and Zika virus lead to major global health and economic problems because of limited treatment options. Therefore, new antiviral drug candidates are urgently needed. The promising new antiviral drug candidate silvestrol effectively inhibited replication of Corona‐, Ebola‐, Zika‐, Picorna‐, Hepatis E and Chikungunya viruses. Besides a direct impact on pathogens, modulation of the host immune system provides an additional facet to antiviral drug development because suitable immune modulation can boost innate defence mechanisms against the pathogens. In the present study, silvestrol down‐regulated several pro‐ and anti‐inflammatory cytokines (IL‐6, IL‐8, IL‐10, CCL2, CCL18) and increased TNF‐α during differentiation and activation of M1‐macrophages, suggesting that the effects of silvestrol might cancel each other out. However, silvestrol amplified the anti‐inflammatory potential of M2‐macrophages by increasing expression of anti‐inflammatory surface markers CD206, TREM2 and reducing release of pro‐inflammatory IL‐8 and CCL2. The differentiation of dendritic cells in the presence of silvestrol is characterized by down‐regulation of several surface markers and cytokines indicating that differentiation is impaired by silvestrol. In conclusion, silvestrol influences the inflammatory status of immune cells depending on the cell type and activation status.     

Variants of the IL‐10 gene associate with muscle strength in elderly from rural Africa: a candidate gene study

Recently, it has been shown that the capacity of the innate immune system to produce cytokines relates to skeletal muscle mass and strength in older persons. The interleukin‐10 (IL‐10) gene regulates the production capacities of IL‐10 and tumour necrosis factor‐α (TNF‐α). In rural Ghana, IL‐10 gene variants associated with different production capacities of IL‐10 and TNF‐α are enriched compared with Caucasian populations. In this setting, we explored the association between these gene variants and muscle strength. Among 554 Ghanaians aged 50 years and older, we determined 20 single nucleotide polymorphisms in the IL‐10 gene, production capacities of IL‐10 and TNF‐α in whole blood upon stimulation with lipopolysaccharide (LPS) and handgrip strength as a proxy for skeletal muscle strength. We distinguished pro‐inflammatory haplotypes associated with low IL‐10 production capacity and anti‐inflammatory haplotypes with high IL‐10 production capacity. We found that distinct haplotypes of the IL‐10 gene associated with handgrip strength. A pro‐inflammatory haplotype with a population frequency of 43.2% was associated with higher handgrip strength (P = 0.015). An anti‐inflammatory haplotype with a population frequency of 7.9% was associated with lower handgrip strength (P = 0.006). In conclusion, variants of the IL‐10 gene contributing to a pro‐inflammatory cytokine response associate with higher muscle strength, whereas those with anti‐inflammatory response associate with lower muscle strength. Future research needs to elucidate whether these effects of variation in the IL‐10 gene are exerted directly through its role in the repair of muscle tissue or indirectly through its role in the defence against infectious diseases.     

Age‐associated changes in long‐chain fatty acid profile during healthy aging promote pro‐inflammatory monocyte polarization via PPARγ

Differences in lipid metabolism associate with age‐related disease development and lifespan. Inflammation is a common link between metabolic dysregulation and aging. Saturated fatty acids (FAs) initiate pro‐inflammatory signalling from many cells including monocytes; however, no existing studies have quantified age‐associated changes in individual FAs in relation to inflammatory phenotype. Therefore, we have determined the plasma concentrations of distinct FAs by gas chromatography in 26 healthy younger individuals (age < 30 years) and 21 healthy FA individuals (age > 50 years). Linear mixed models were used to explore the association between circulating FAs, age and cytokines. We showed that plasma saturated, poly‐ and mono‐unsaturated FAs increase with age. Circulating TNF‐α and IL‐6 concentrations increased with age, whereas IL‐10 and TGF‐β1 concentrations decreased. Oxidation of MitoSOX Red was higher in leucocytes from FA adults, and plasma oxidized glutathione concentrations were higher. There was significant colinearity between plasma saturated FAs, indicative of their metabolic relationships. Higher levels of the saturated FAs C18:0 and C24:0 were associated with lower TGF‐β1 concentrations, and higher C16:0 were associated with higher TNF‐α concentrations. We further examined effects of the aging FA profile on monocyte polarization and metabolism in THP1 monocytes. Monocytes preincubated with C16:0 increased secretion of pro‐inflammatory cytokines in response to phorbol myristate acetate‐induced differentiation through ceramide‐dependent inhibition of PPARγ activity. Conversely, C18:1 primed a pro‐resolving macrophage which was PPARγ dependent and ceramide dependent and which required oxidative phosphorylation. These data suggest that a midlife adult FA profile impairs the switch from proinflammatory to lower energy, requiring anti‐inflammatory macrophages through metabolic reprogramming.     

Necroptosis increases with age and is reduced by dietary restriction

Necroptosis is a newly identified programmed cell death pathway that is highly proinflammatory due to the release of cellular components that promote inflammation. To determine whether necroptosis might play a role in inflammaging, we studied the effect of age and dietary restriction (DR) on necroptosis in the epididymal white adipose tissue (eWAT), a major source of proinflammatory cytokines. Phosphorylated MLKL and RIPK3, markers of necroptosis, were increased 2.7‐ and 1.9‐fold, respectively, in eWAT of old mice compared to adult mice, and DR reduced P‐MLKL and P‐RIPK3 to levels similar to adult mice. An increase in the expression of RIPK1 (1.6‐fold) and MLKL (2.7‐fold), not RIPK3, was also observed in eWAT of old mice, which was reduced by DR in old mice. The increase in necroptosis was paralleled by an increase in 14 inflammatory cytokines, including the pro‐inflammatory cytokines IL‐6 (3.9‐fold), TNF‐α (4.7‐fold), and IL‐1β (5.1‐fold)], and 11 chemokines in old mice. DR attenuated the expression of IL‐6, TNF‐α, and IL‐1β as well as 85% of the other cytokines/chemokines induced with age. In contrast, inguinal WAT (iWAT), which is less inflammatory, did not show any significant increase with age in the levels of P‐MLKL and MLKL or inflammatory cytokines/chemokines. Because the changes in biomarkers of necroptosis in eWAT with age and DR paralleled the changes in the expression of pro‐inflammatory cytokines, our data support the possibility that necroptosis might play a role in increased chronic inflammation observed with age.     

Activation of human bronchial epithelial cells by inflammatory cytokines IL‐27 and TNF‐α: Implications for immunopathophysiology of airway inflammation

Interleukin (IL)‐27 is a member of IL‐6/IL‐12 family cytokines produced by antigen‐presenting cells in immune responses. IL‐27 can drive the commitment of naive T cells to a T helper type 1 (Th1) phenotype and inhibit inflammation in later phases of infection. Human bronchial epithelial cells have been shown to express IL‐27 receptor complex. In this study, we investigated the in vitro effects of IL‐27, alone or in combination with inflammatory cytokine tumor necrosis factor (TNF)‐α on the pro‐inflammatory activation of human primary bronchial epithelial cells and the underlying intracellular signaling mechanisms. IL‐27 was found to enhance intercellular adhesion molecule 1 (ICAM‐1) expression on the surface of human bronchial epithelial cells, and a synergistic effect was observed in the combined treatment of IL‐27 and TNF‐α on the expression of ICAM‐1. Although IL‐27 did not alter the basal IL‐6 secretion from bronchial epithelial cells, it could significantly augment TNF‐α‐induced IL‐6 release. These synergistic effects on the up‐regulation of ICAM‐1 and IL‐6 were partially due to the elevated expression of TNF‐α receptor (p55TNFR) induced by IL‐27. Further investigations showed that the elevation of ICAM‐1 and IL‐6 in human bronchial epithelial cells stimulated by IL‐27 and TNF‐α was differentially regulated by phosphatidylinositol 3‐OH kinase (PI3K)‐Akt, p38 mitogen‐activated protein kinase, and nuclear factor‐κB pathways. Our results therefore provide a new insight into the molecular mechanisms involved in airway inflammation. J. Cell. Physiol. 223:788–797, 2010. © 2010 Wiley‐Liss, Inc.     

Preventive effect of phytoglycoprotein (27 kDa) on inflammatory factors at liver injury in cadmium chloride-exposed ICR mice

Cadmium is one of the inflammation‐related xenobiotics and has been regarded as a potent carcinogen. Gardenia jasminoides Ellis (GJE) has been used to cure inflammation in Korean folk medicine for a long time. The purpose of present study is the inhibitory effect of glycoprotein isolated from GJE (27 kDa) on inflammation mechanism in cadmium chloride‐exposed ICR mice. We evaluated the activities of lactate dehydrogenase (LDH), alanine aminotransferase (ALT), and thiobarbituric acid‐reactive substances (TBARS), activities of anti‐oxidative enzymes [superoxide dismutase (SOD) and gluthathione peroxidase (GPx)], activities of c‐Jun N‐terminal protein kinase (JNK), heat shock protein 27 (Hsp27), activator protein (AP)‐1, nuclear factor (NF)‐κB and expression of inflammation‐related mediators including tumor necrosis factor (TNF)‐α and interleukin (IL)‐6 in cadmium chloride‐exposed ICR mice using immunoblot analysis, EMSA and RT‐PCR. It notes that mice plasma was used to measure ALT, LDH, and TBARS after treatment with cadmium chloride alone or cadmium chloride under the pretreatment with GJE glycoprotein. Liver tissues were used to assess activities of anti‐oxidant enzymes, SAPK/JNK, Hsp27, AP‐1, NF‐κB, TNF‐α, and IL‐6 in this study. The results obtained from this study revealed that GJE glycoprotein (10 mg/kg) decreased the levels of LDH, ALT and TBARS, whereas increased the activity of hepatic anti‐oxidant enzymes (SOD and GPx) in cadmium chloride‐exposed ICR mice. Moreover, it decreased the activity of JNK/AP‐1, NF‐κB, Hsp27, and pro‐inflammatory cytokines (TNF‐α and IL‐6). Taken together, the results in this study suggest that GJE glycoprotein inhibits the expression of inflammation‐related cytokines (TNF‐α and IL‐6) in cadmium chloride‐exposed ICR mice. J. Cell. Biochem. 112: 694–703, 2011. © 2010 Wiley‐Liss, Inc.     

IL‐35 recombinant protein reverses inflammatory bowel disease and psoriasis through regulation of inflammatory cytokines and immune cells

Interleukin‐35 (IL‐35), a member of the IL‐12 family, functions as a new anti‐inflammatory factor involved in arthritis, psoriasis, inflammatory bowel disease (IBD) and other immune diseases. Although IL‐35 can significantly prevent the development of inflammation in many diseases, there have been no early studies accounting for the role of IL‐35 recombinant protein in IBD and psoriasis. In this study, we assessed the therapeutic potential of IL‐35 recombinant protein in three well‐known mouse models: the dextransulfate sodium (DSS)‐induced colitis mouse model, the keratin14 (K14)‐vascular endothelial growth factor A (VEGF‐A)‐transgenic (Tg) psoriasis mouse model and the imiquimod (IMQ)‐induced psoriasis mouse model. Our results indicated that IL‐35 recombinant protein can slow down the pathologic process in DSS‐induced acute colitis mouse model by decreasing the infiltrations of macrophages, CD4⁺T and CD8⁺T cells and by promoting the infiltration of Treg cells. Further analysis demonstrated that IL‐35 recombinant protein may regulate inflammation through promoting the secretion of IL‐10 and inhibiting the expression of pro‐inflammatory cytokines such as IL‐6, TNF‐α and IL‐17 in acute colitis model. In addition, lower dose of IL‐35 recombinant protein could achieve long‐term treatment effects as TNF‐α monoclonal antibody did in the psoriasis mouse. In summary, the remarkable therapeutic effects of IL‐35 recombinant protein in acute colitis and psoriasis mouse models indicated that IL‐35 recombinant protein had a variety of anti‐inflammatory effects and was expected to become an effective candidate drug for the treatment of inflammatory diseases.     

Peroxiredoxin-1, a possible target in modulating inflammatory cytokine production in macrophage like cell line RAW264.7

Peroxiredoxin (PRX), a scavenger of H₂O₂ and alkyl hydroperoxides in living organisms, protects cells from oxidative stress. Contrary to its known anti‐oxidant roles, the involvement of PRX‐1 in the regulation of lipopolysaccharide (LPS) signaling is poorly understood, possible immunological functions of PRX‐1 having been uncovered only recently. In the present study, it was discovered that the PRX‐1 deficient macrophage like cell line (RAW264.7) has anti‐inflammatory activity when stimulated by LPS. Treatment with LPS for 3 hrs resulted in increased gene expression of an anti‐inflammatory cytokine, interleukin‐10 (IL‐10), in PRX‐1 knock down RAW264.7 cells. Gene expression of pro‐inflammatory cytokines IL‐1β and tumor necrosis factor‐ α (TNF‐α) did not show notable changes under the same conditions. However, production of these cytokines significantly decreased in PRX‐1 knock down RAW264.7 cells with 12 hrs of stimulation. Production of IL‐10 was also increased in PRX‐1 knock down RAW264.7 cells with 12 hrs of stimulation. We predicted that higher concentrations of IL‐10 would result in decreased expression of IL‐1β and TNF‐α in PRX‐1 knock‐down cells. This was confirmed by blocking IL‐10, which reestablished IL‐1β and TNF‐α secretion. We also observed that increased concentrations of IL‐10 do not affect the NF‐κB pathway. Interestingly, STAT3 phosphorylation by LPS stimulation was significantly increased in PRX‐1 knockdown RAW264.7 cells. Up‐regulation of IL‐10 in PRX‐1 knockdown cells and the resulting downregulation of proinflammatory cytokine production seem to involve the STAT3 pathway in macrophages. Thus, down‐regulation of PRX‐1 may contribute to the suppression of adverse effects caused by excessive activation of macrophages through affecting the STAT3 signaling pathway.     

Murine macrophage inflammatory cytokine production and immune activation in response to Vibrio parahaemolyticus infection

Vibrio parahaemolyticus is the most common cause of bacterial, seafood‐related illness in the USA. Currently, there is a dearth of published reports regarding immunity to infection with this pathogen. Here, production of both pro‐ and anti‐inflammatory cytokines by V. parahaemolyticus‐infected RAW 264.7 murine macrophages was studied. It was determined that this infection results in increased concentrations of IL‐1α, IL‐6, TNF‐α and IL‐10. Additionally, decreases in cell surface TLR2 and TLR4 and increases in T‐cell co‐stimulatory molecules CD40 and CD86 were discovered. The data presented here begin to identify the immune variables required to eliminate V. parahaemolyticus from infected host tissues.     

Aminooxyacetic acid attenuates post‐infarct cardiac dysfunction by balancing macrophage polarization through modulating macrophage metabolism in mice

Excessive activation of pro‐inflammatory M1 macrophages following acute myocardial infarction (MI) aggravates adverse cardiac remodelling and heart dysfunction. There are two break points in the tricarboxylic acid cycle of M1 macrophages, and aspartate‐arginosuccinate shunt compensates them. Aminooxyacetic acid (AOAA) is an inhibitor of aspartate aminotransferase in the aspartate‐arginosuccinate shunt. Previous studies showed that manipulating macrophage metabolism may control macrophage polarization and inflammatory response. In this study, we aimed to clarify the effects of AOAA on macrophage metabolism and polarization and heart function after MI. In vitro, AOAA inhibited lactic acid and glycolysis and enhanced ATP levels in classically activated M1 macrophages. Besides, AOAA restrained pro‐inflammatory M1 macrophages and promoted anti‐inflammatory M2 phenotype. In vivo, MI mice were treated with AOAA or saline for three consecutive days. Remarkably, AOAA administration effectively inhibited the proportion of M1 macrophages and boosted M2‐like phenotype, which subsequently attenuated infarct size as well as improved post‐MI cardiac function. Additionally, AOAA attenuated NLRP3‐Caspase1/IL‐1β activation and decreased the release of IL‐6 and TNF‐α pro‐inflammatory cytokines and reciprocally increased IL‐10 anti‐inflammatory cytokine level in both ischaemic myocardium and M1 macrophages. In conclusion, short‐term AOAA treatment significantly improves cardiac function in mice with MI by balancing macrophage polarization through modulating macrophage metabolism and inhibiting NLRP3‐Caspase1/IL‐1β pathway.     

IL‐1β and TNF‐α induce neurotoxicity through glutamate production: a potential role for neuronal glutaminase

Glutaminase 1 is the main enzyme responsible for glutamate production in mammalian cells. The roles of macrophage and microglia glutaminases in brain injury, infection, and inflammation are well documented. However, little is known about the regulation of neuronal glutaminase, despite neurons being a predominant cell type of glutaminase expression. Using primary rat and human neuronal cultures, we confirmed that interleukin‐1β (IL‐1β) and tumor necrosis factor‐α (TNF‐α), two pro‐inflammatory cytokines that are typically elevated in neurodegenerative disease states, induced neuronal death and apoptosis in vitro. Furthermore, both intracellular and extracellular glutamate levels were significantly elevated following IL‐1β and/or TNF‐α treatment. Pre‐treatment with N‐Methyl‐d ‐aspartate (NMDA) receptor antagonist MK‐801 blocked cytokine‐induced glutamate production and alleviated the neurotoxicity, indicating that IL‐1β and/or TNF‐α induce neurotoxicity through glutamate. To determine the potential source of excess glutamate production in the culture during inflammation, we investigated the neuronal glutaminase and found that treatment with IL‐1β or TNF‐α significantly upregulated the kidney‐type glutaminase (KGA), a glutaminase 1 isoform, in primary human neurons. The up‐regulation of neuronal glutaminase was also demonstrated in situ in a murine model of HIV‐1 encephalitis. In addition, IL‐1β or TNF‐α treatment increased the levels of KGA in cytosol and TNF‐α specifically increased KGA levels in the extracellular fluid, away from its main residence in mitochondria. Together, these findings support neuronal glutaminase as a potential component of neurotoxicity during inflammation and that modulation of glutaminase may provide therapeutic avenues for neurodegenerative diseases.     

Inflammatory cytokines promote growth of intestinal smooth muscle cells by induced expression of PDGF‐Rβ

Thickening of the inflamed intestinal wall involves growth of smooth muscle cells (SMC), which contributes to stricture formation. Earlier, the growth factor platelet‐derived growth factor (PDGF)‐BB was identified as a key mitogen for SMC from the rat colon (CSMC), and CSMC growth in colitis was associated with both appearance of its receptor, PDGF‐Rβ and modulation of phenotype. Here, we examined the role of inflammatory cytokines in inducing and modulating the growth response to PDGF‐BB. CSMC were enzymatically isolated from Sprague–Dawley rats, and the effect of tumour necrosis factor (TNF)‐α, interleukin (IL)‐1β, transforming growth factor (TGF), IL‐17A and IL‐2 on CSMC growth and responsiveness to PDGF‐BB were assessed using proliferation assays, PCR and western blotting. Conditioned medium (CM) was obtained at 48 hrs of trinitrobenzene sulphonic acid‐induced colitis. Neither CM alone nor cytokines caused proliferation of early‐passage CSMC. However, CM from inflamed, but not control colon significantly promoted the effect of PDGF‐BB. IL‐1β, TNF‐α and IL‐17A, but not other cytokines, increased the effect of PDGF‐BB because of up‐regulation of mRNA and protein for PDGF‐Rβ without change in receptor phosphorylation. PDGF‐BB was identified in adult rat serum (RS) and RS‐induced CSMC proliferation was inhibited by imatinib, suggesting that blood‐derived PDGF‐BB is a local mitogen in vivo. In freshly isolated CSMC, CM from the inflamed colon as well as IL‐1β and TNF‐α induced the early expression of PDGF‐Rβ, while imatinib blocked subsequent RS‐induced cell proliferation. Thus, pro‐inflammatory cytokines both initiate and maintain a growth response in CSMC via PDGF‐Rβ and serum‐derived PDGF‐BB, and control of PDGF‐Rβ expression may be beneficial in chronic intestinal inflammation.     

Anti‐inflammatory effects of activated protein C on human dendritic cells

Activated protein C (APC) has an anticoagulant action and plays an important role in blood coagulation homeostasis. In addition to its anticoagulant action, APC is known to have cytoprotective effects, such as anti‐apoptotic action and endothelial barrier protection, on vascular endothelial cells and monocytes. However, the effects of APC on DCs have not been clarified. To investigate the effects of APC on human DCs, monocytes were isolated from peripheral blood and DC differentiation induced with LPS. APC significantly inhibited the production of inflammatory cytokines TNF‐α and IL‐6 during differentiation of immature DCs to mature DCs, but did not inhibit the production of IL‐12 and anti‐inflammatory cytokine IL‐10. Interestingly, treatment with 5 μg/mL, but not 25 μg/mL, of APC significantly enhanced production of IL‐10. In addition, protein C, which is the zymogen of APC, did not affect production of these cytokines. On the other hand, flow cytometric analysis of DC's surface molecules indicated that APC does not significantly affect expression of CD83, a marker of mDC differentiation, and the co‐stimulatory molecules CD40, CD80 and CD86. These results suggest that APC has anti‐inflammatory effects on human DCs and may be effective against some inflammatory diseases in which the pathogenesis involves TNF‐α and/or IL‐6 production.