Interleukin-10 suppresses tissue factor expression in lipopolysaccharide-stimulated macrophages via inhibition of Egr-1 and a serum response element/MEK-ERK1/2 pathway

Single-cell analysis reveals TLR-induced macrophage heterogeneity and quorum sensing dictate population wide anti-inflammatory feedback in response to LPS

The role of macrophages in controlling tissue inflammation is indispensable to ensure a context-appropriate response to pathogens whilst preventing excessive tissue damage. Their initial response is largely characterized by high production of tumor necrosis factor alpha (TNFα) which primes and attracts other immune cells, thereafter, followed by production of interleukin 10 (IL-10) which inhibits cell activation and steers towards resolving of inflammation. This delicate balance is understood at a population level but how it is initiated at a single-cell level remains elusive. Here, we utilize our previously developed droplet approach to probe single-cell macrophage activation in response to toll-like receptor 4 (TLR4) stimulation, and how single-cell heterogeneity and cellular communication affect macrophage-mediated inflammatory homeostasis. We show that only a fraction of macrophages can produce IL-10 in addition to TNFα upon LPS-induced activation, and that these cells are not phenotypically different from IL-10 non-producers nor exhibit a distinct transcriptional pathway. Finally, we demonstrate that the dynamics of TNFα and IL-10 are heavily controlled by macrophage density as evidenced by 3D hydrogel cultures suggesting a potential role for quorum sensing. These exploratory results emphasize the relevance of understanding the complex communication between macrophages and other immune cells and how these amount to population-wide responses.

Long Noncoding RNA MIAT Controls Advanced Atherosclerotic Lesion Formation and Plaque Destabilization

Supplemental Digital Content is available in the text.

Long noncoding RNAs (lncRNAs) are important regulators of biological processes involved in vascular tissue homeostasis and disease development. The present study assessed the functional contribution of the lncRNA myocardial infarction-associated transcript (MIAT) to atherosclerosis and carotid artery disease.

Role of SARS-CoV-2 -induced cytokines and growth factors in coagulopathy and thromboembolism

Severe COVID-19 patients frequently present thrombotic complications which commonly lead to multiorgan failure and increase the risk of death. Severe SARS-CoV-2 infection induces the cytokine storm and is often associated with coagulation dysfunction. D-dimer, a hallmark of venous thromboembolism (VTE), is observed at a higher level in the majority of hospitalized COVID-19 patients. The precise molecular mechanism of the disproportionate effect of SARS-CoV-2 infection on the coagulation system is largely undefined. SARS-CoV-2 -induced endotheliopathy and, induction of cytokines and growth factors (GFs) most likely play important roles in platelet activation, coagulopathy, and VTE. Generally, viral infections lead to systemic inflammation and induction of numerous cytokines and GFs and many of them are reported to be associated with increased VTE. Most importantly, platelets play key thromboinflammatory roles linking coagulation to immune mediators in a variety of infections including response to viral infection. Since the pathomechanism of coagulopathy and VTE in COVID-19 is largely undefined, herein we highlight the association of dysregulated inflammatory cytokines and GFs with thrombotic complications and coagulopathy in COVID-19.

Cytokines as therapeutic targets for cardio- and cerebrovascular diseases

Despite major advances in prevention and treatment, cardiac and cerebral atherothrombotic complications still account for substantial morbidity and mortality worldwide. In this context, inflammation is involved in the chronic process leading atherosclerotic plaque formation and its complications, as well as in the maladaptive response to acute ischemic events. For this reason, modulation of inflammation is nowadays seen as a promising therapeutic strategy to counteract the burden of cardio- and cerebrovascular disease. Being produced and recognized by both inflammatory and vascular cells, the complex network of cytokines holds key functions in the crosstalk of these two systems and orchestrates the progression of atherothrombosis. By binding to membrane receptors, these soluble mediators trigger specific intracellular signaling pathways eventually leading to the activation of transcription factors and a deep modulation of cell function. Both stimulatory and inhibitory cytokines have been described and progressively reported as markers of disease or interesting therapeutic targets in the cardiovascular field. Nevertheless, cytokine inhibition is burdened by harmful side effects that will most likely prevent its chronic use in favor of acute administrations in well-selected subjects at high risk. Here, we summarize the current state of knowledge regarding the modulatory role of cytokines on atherosclerosis, myocardial infarction, and stroke. Then, we discuss evidence from clinical trials specifically targeting cytokines and the potential implication of these advances into daily clinical practice.

Tissue Engineered Vascular Graft Recipient Interleukin 10 Status Is Critical for Preventing Thrombosis

Tissue engineered vascular grafts (TEVGs) are a promising technology, but are hindered by occlusion. Seeding with bone-marrow derived mononuclear cells (BM-MNCs) mitigates occlusion, yet the precise mechanism remains unclear. Seeded cells disappear quickly and potentially mediate an anti-inflammatory effect through paracrine signaling. Here, a series of reciprocal genetic TEVG implantations plus recombinant protein treatment is reported to investigate what role interleukin-10, an anti-inflammatory cytokine, plays from both host and seeded cells. TEVGs seeded with BM-MNCs from wild-type and IL-10 KO mice, plus unseeded grafts, are implanted into wild-type and IL-10 KO mice. Wild-type mice with unseeded grafts also receive recombinant IL-10. Serial ultrasound evaluates occlusion and TEVGs are harvested at 14 d for immunohistochemical analysis. TEVGs in IL-10 KO mice have significantly higher occlusion incidence compared to wild-type mice attributed to acute (<3 d) thrombosis. Cell seeding rescues TEVGs in IL-10 KO mice comparable to wild-type patency. IL-10 from the host and seeded cells do not significantly influence graft inflammation and macrophage phenotype, yet IL-10 treatment shows interesting biologic effects including decreasing cell proliferation and increasing M2 macrophage polarization. IL-10 from the host is critical for preventing TEVG thrombosis and seeded BM-MNCs exert a significant anti-thrombotic effect in IL-10 KO mice.

Beyond thrombosis: the impact of tissue factor signaling in cancer

Tissue factor (TF) is the primary initiator of the coagulation cascade, though its effects extend well beyond hemostasis. When TF binds to Factor VII, the resulting TF:FVIIa complex can proteolytically cleave transmembrane G protein-coupled protease-activated receptors (PARs). In addition to activating PARs, TF:FVIIa complex can also activate receptor tyrosine kinases (RTKs) and integrins. These signaling pathways are utilized by tumors to increase cell proliferation, angiogenesis, metastasis, and cancer stem-like cell maintenance. Herein, we review in detail the regulation of TF expression, mechanisms of TF signaling, their pathological consequences, and how it is being targeted in experimental cancer therapeutics.

Low Systemic Levels of Chemokine C-C Motif Ligand 3 (CCL3) are Associated with a High Risk of Venous Thromboembolism in Patients with Glioma

A tight interplay between inflammation and hemostasis has been described as a potential driver for developing venous thromboembolism (VTE). Here, we investigated the association of systemic cytokine levels and risk of VTE in patients with glioma. This analysis was conducted within the prospective, observational Vienna Cancer and Thrombosis Study. Patients with glioma were included at time of diagnosis or progression and were observed for a maximum of two years. Primary endpoint was objectively confirmed VTE. At study entry, a single blood draw was performed. A panel of nine cytokines was measured in serum samples with the xMAP technology developed by Luminex. Results: Overall, 76 glioma patients were included in this analysis, and 10 (13.2%) of them developed VTE during the follow-up. Chemokine C-C motif ligand 3 (CCL3) levels were inversely associated with risk of VTE (hazard ratio [HR] per double increase, 95% confidence interval [CI]: 0.385, 95% CI: 0.161–0.925, p = 0.033), while there was no association between the risk of VTE and serum levels of interleukin (IL)-1β, IL-4, IL-6, IL-8, IL-10, IL-11, tumor necrosis factor (TNF)-α and vascular endothelial growth factor (VEGF), respectively. In conclusion, low serum levels of CCL3 were associated with an increased risk of VTE. CCL3 might serve as a potential biomarker to predict VTE risk in patients with glioma.

Anticoagulant effect of wogonin against tissue factor expression

Tissue factor (TF) is the primary cause of atherothrombosis, the rupture of atherosclerotic plaques with subsequent thrombosis, leading to acute cardiovascular events, such as myocardial infarction and stroke. Wogonin (Wog) is an active component of Scutellaria baicalensis, used for inflammatory diseases, atherosclerosis, and hyperlipidemia. The anticoagulant effect of Wog on TF expression remains unexplored. In this study, we have investigated the effects of Wog on TF gene expression and its underlying molecular mechanism in human vascular endothelial cells (ECs). We found that Wog dose-dependently inhibited PMA-enhanced TF mRNA, protein, and activity in ECs. This inhibition was attributed to its decreasing nuclear accumulations of transcription factors, phospho-c-Jun and early growth response-1(Egr-1), not nuclear factor-κB (NF-κB), through blocking extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) signaling pathways. Reduction by Wog of Egr-1 nuclear level and Egr-1/DNA binding activity was associated with its inhibition of Egr-1 de novo synthesis. Wog as well as inhibitors to ERK and JNK suppressed TF promoter activity and protein expression in reporter gene and Western blot analyses. Furthermore, it also exhibited anticoagulant function by inhibiting TF expression and activity in tumor necrosis factor-alpha (TNF-α)- and lipopolysaccharide (LPS)-treated ECs and THP-1 cells. These results suggest that Wog inhibits ERK/Egr-1- and JNK/AP-1-mediated transactivation of TF promoter activity, leading to downregulation of TF expression and activity induced by inflammatory mediators. Wog targeting pathological TF expression without affecting its basal level may be a safer templet in the development of anticoagulant agent for cardiovascular thrombotic diseases related to atherothrombosis.

γ-Oryzanol suppresses COX-2 expression by inhibiting reactive oxygen species-mediated Erk1/2 and Egr-1 signaling in LPS-stimulated RAW264.7 macrophages

Cyclooxygenase (COX)-2 produces prostanoids, which contribute to inflammatory responses. Nuclear factor (NF)-κB is a key transcription factor mediating COX-2 expression. γ-Oryzanol is an active component in rice bran oil, which inhibits lipopolysaccharide (LPS)-mediated COX-2 expression by inhibiting NF-κB. However, the inhibition of COX-2 expression by γ-oryzanol independently of NF-κB is poorly understood. We found that LPS upregulated Egr-1 expression at the transcriptional level. Forced expression of Egr-1 trans-activated the Cox-2 promoter independently of NF-κB. In contrast, silencing of Egr-1 abrogated LPS-mediated COX-2 expression. LPS produced reactive oxygen species (ROS), which, in turn, induced Egr-1 expression via the Erk1/2 MAPK pathway. ROS scavenging activity of γ-oryzanol suppressed Egr-1 expression by inhibiting the Erk1/2 MAPK pathway. Our results suggest that γ-oryzanol inhibits LPS-mediated COX-2 expression by suppressing Erk1/2-mediated Egr-1 expression. This study supports that γ-oryzanol may be useful for ameliorating LPS-mediated inflammatory responses.

Interdependencies among Selected Pro-Inflammatory Markers of Endothelial Dysfunction, C-Peptide, Anti-Inflammatory Interleukin-10 and Glucose Metabolism Disturbance in Obese Women

BACKGROUND

Currently increasing importance is attributed to the inflammatory process as a crucial factor responsible for the progressive damage to vascular walls and progression of atherosclerosis in obese people. We have studied the relationship between clinical and biochemical parameters and C-peptide and anti-inflammatory IL-10, as well as selected markers of inflammation and endothelial dysfunction such as: CCL2, CRP, sICAM-1, sVCAM-1 and E-selectin in obese women with various degree of glucose metabolism disturbance.

MATERIAL AND METHODS

The studied group consisted of 61 obese women, and 20 normal weight, healthy volunteers. Obese patients were spited in subgroups based on the degree of glucose metabolism disorder. Serum samples were analyzed using ELISA kits.

RESULTS

Increased concentrations of sICAM-1, sVCAM-1, E-selectin, CCL2 and CRP were found in all obese groups compared to the normal weight subjects. In patients with Type 2 diabetes mellitus (T2DM) parameters characterizing the degree of obesity significantly positively correlated with levels of CRP and CCL2. Significant relationships were found between levels of glucose and sICAM-1and also E-selectin and HOMA-IR. C-peptide levels are positively associated with CCL2, E-selectin, triglycerides levels, and inversely with IL-10 levels in newly diagnosed T2DM group (p<0.05). Concentrations of IL-10 correlated negatively with E-selectin, CCL2, C-peptide levels, and HOMA-IR in T2DM group (p<0.05).

CONCLUSION

Disturbed lipid and carbohydrate metabolism are manifested by enhanced inflammation and endothelial dysfunction in patients with simply obesity. These disturbances are associates with an increase of adhesion molecules. The results suggest the probable active participation of higher concentrations of C-peptide in the intensification of inflammatory and atherogenic processes in obese patients with type 2 diabetes. In patients with obesity and type 2 diabetes, altered serum concentrations of Il-10 seems to be dependent on the degree of insulin resistance and proinflammatory status.

beta-Naphthoflavone protects from peritonitis by reducing TNF-alpha-induced endothelial cell activation

β-Naphthoflavone (β-NF), a ligand of the aryl hydrocarbon receptor, has been shown to possess anti-oxidative properties. We investigated the anti-oxidative and anti-inflammatory potential of β-NF in human microvascular endothelial cells treated with tumor necrosis factor-alpha (TNF-α). Pretreatment with β-NF significantly inhibited TNF-α-induced intracellular reactive oxygen species, translocation of p67(phox), and TNF-α-induced monocyte binding and transmigration. In addition, β-NF significantly inhibited TNF-α-induced ICAM-1 and VCAM-1 expression. The mRNA expression levels of the inflammatory cytokines TNF-α and IL-6 were reduced by β-NF, as was the infiltration of white blood cells, in a peritonitis model. The inhibition of adhesion molecules was associated with suppressed nuclear translocation of NF-κB p65 and Akt, and suppressed phosphorylation of ERK1/2 and p38. The translocation of Egr-1, a downstream transcription factor involved in the MEK-ERK signaling pathway, was suppressed by β-NF treatment. Our findings show that β-NF inhibits TNF-α-induced NF-kB and ERK1/2 activation and ROS generation, thereby suppressing the expression of adhesion molecules. This results in reduced adhesion and transmigration of leukocytes in vitro and prevents the infiltration of leukocytes in a peritonitis model. Our findings also suggest that β-NF might prevent TNF-α-induced inflammation.

Interleukin-10 protects against atherosclerosis by modulating multiple atherogenic macrophage function

Atherosclerosis is primarily a disorder of lipid metabolism, but there is also a prominent chronic inflammatory component that drives the atherosclerotic lesion progression in the artery wall. During hyperlipidaemic conditions, there is a rapid influx of circulating monocytes into the atherosclerosis-prone areas of the arterial intima. These infiltrated monocytes differentiate into macrophages and take up the atherogenic lipoproteins in the intima of the vessel wall that have been modified within the lesion environment. Interleukin (IL)-10 is a prototypic anti-inflammatory cytokine made primarily by the macrophages and Th2 subtype T lymphocytes. In terms of atherosclerosis its major roles include inhibition of macrophage activation as well as inhibition of matrix metalloproteinase, pro-inflammatory cytokines and cyclooxygenase-2 expression in lipid-loaded and activated macrophage foam cells. Recent discoveries suggest another important role of IL-10 in atherosclerosis: its ability to alter lipid metabolism in macrophages. The current review will highlight the present knowledge on multiple ways in which IL-10 mediates atherosclerosis. As macrophages play a critical role in all stages of atherosclerosis, the review will concentrate on how IL-10 regulates the activities of macrophages that are especially important in the development of atherosclerosis.

Dextromethorphan attenuates LPS-induced adhesion molecule expression in human endothelial cells

OBJECTIVE

This study examines the effect of Dextromethorphan (d-3-methoxy-17-methylmorphinan; DXM), a commonly used cough-suppressing drug, on the expression of VCAM-1 and ICAM-1 in human umbilical vein endothelial cells (HUVECs) stimulated with lipopolysaccharide (LPS).

METHODS

The effect of DXM on expression of cell adhesion molecules induced by LPS was evaluated by monocyte bindings in vitro and ex vivo and transmigration assays. The signaling pathways involved in the inflammation inhibitory effect of DXM were analyzed by Western blot and immunofluorescent stain.

RESULTS

Pretreatment of HUVECs with DXM inhibited LPS-induced adhesion of THP-1 cells in vitro and ex vivo, and reduced transendothelial migration of these cells. Furthermore, treatment of HUVECs with DXM can significantly decrease LPS-induced expression of ICAM-1 and VCAM-1. DXM abrogated LPS-induced phosphorylation of ERK and Akt. The translocation of early growth response gene-1 (Egr-1), a downstream transcription factor involved in the mitogen-activated kinase (MEK)-ERK signaling pathway, was suppressed by DXM treatment. Furthermore, DXM inhibited LPS-induced IκBα degradation and nuclear translocation of p65.

CONCLUSIONS

Dextromethorphan inhibits the adhesive capacity of HUVECs by reducing the LPS-induced ICAM-1 and VCAM-1 expression via the suppression of the ERK, Akt, and NF-κB signaling pathways. Thus, DXM is a potential anti-inflammatory therapeutic that may modulate atherogenesis.

Cell-Type Specific Determinants of NRAMP1 Expression in Professional Phagocytes

The Natural resistance-associated macrophage protein 1 (Nramp1 or Solute carrier 11 member 1, Slc11a1) transports divalent metals across the membrane of late endosomes and lysosomes in professional phagocytes. Nramp1 represents an ancient eukaryotic cell-autonomous defense whereas the gene duplication that yielded Nramp1 and Nramp2 predated the origin of Sarcopterygians (lobe-finned fishes and tetrapods). SLC11A1 genetic polymorphisms associated with human resistance to tuberculosis consist of potential regulatory variants. Herein, current knowledge of the regulation of SLC11A1 gene expression is reviewed and comprehensive analysis of ENCODE data available for hematopoietic cell-types suggests a hypothesis for the regulation of SLC11A1 expression during myeloid development and phagocyte functional polarization. SLC11A1 is part of a 34.6 kb CTCF-insulated locus scattered with predicted regulatory elements: a 3' enhancer, a large 5' enhancer domain and four elements spread around the transcription start site (TSS), including several C/EBP and PU.1 sites. SLC11A1 locus ends appear mobilized by ETS-related factors early during myelopoiesis; activation of both 5' and 3' enhancers in myelo-monocytic cells correlate with transcription factor binding at the TSS. Characterizing the corresponding cis/trans determinants functionally will establish the mechanisms involved and possibly reveal genetic variation that impacts susceptibility to infectious or immune diseases.

A dietary resveratrol-rich grape extract prevents the developing of atherosclerotic lesions in the aorta of pigs fed an atherogenic diet

The presence of grape and wine polyphenol resveratrol (RES) in the diet is negligible. Therefore, the cardiovascular benefits of this molecule, in a dietary context, remain to be established. We aimed to investigate, through dietary intervention, the effects of a resveratrol-rich grape extract (GE-RES) on the prevention of early aortic lesions in pigs fed an atherogenic diet (AD). These effects were compared with those produced by a grape extract lacking RES (GE) or RES alone. Pigs fed the AD for 4 months showed early atherosclerotic lesions in the thoracic aorta: degeneration and fragmentation of elastic fibers, increase of intima thickness, subendothelial fibrosis, and accumulation of fatty cells and anion superoxide radicals. GE-RES was the most effective treatment and prevented the disruption of aortic elastic fibers, decreased their alteration (57%), and reduced the intima thickness (33%) and the accumulation of fatty cells (42%) and O(2)(•-) (38%) in aortic tissue. In addition, GE-RES moderately downregulated the expression of the suppressors of cytokine signaling 1 (SOCS1) and 3 (SOCS3), key regulators of vascular cell responses, in peripheral mononuclear blood cells. Our results suggest that the consumption of this GE-RES nutraceutical, in a dietary prevention context, could prevent early atherosclerotic events. The presence of RES in the grape extract strengthened these effects.

Expression of IL-17A in human atherosclerotic lesions is associated with increased inflammation and plaque vulnerability

A chronic (auto)immune response is the critical mechanism in atherosclerosis. Interleukin-17A is a pivotal effector cytokine, which modulates immune cell trafficking and initiates inflammation in (auto)immune and infectious diseases. However, expression of IL-17A in the context of human atherosclerosis has hardly been explored. Carotid artery plaques were collected from 79 patients undergoing endarterectomy. Patients were grouped according to their symptomatic status (TIA, stroke), plaque morphology and medication. Quantitative RT-PCR was used to analyze tissue inflammation and immunohistochemistry to assess cellular source of IL-17A expression and lesion morphology. Carotid plaques from patients with ischemic symptoms were characterized by a highly activated inflammatory milieu including accumulation of T cells (p = 0.04) and expression of IL-6 and VCAM1 (p = 0.02, 0.01). Expression of IL-17A and its positive regulators IL-21 and IL-23 was present in atherosclerotic lesions, significantly upregulated in atheromas of symptomatic patients (p = 0.005, 0.004, 0.03), and expression of IL-17A and IL-21 showed a strong correlation (p = 0.002, r = 0.52). The cellular sources of lesional IL-17A expression are T cells, macrophages, B cells and plasma cells. Vulnerable/ruptured (complicated) plaques were significantly associated with IL-17A expression levels (p = 0.003). In addition, IL-17A showed a marked negative correlation with the potent anti-inflammatory/atheroprotective cytokine IL-10 (p = 0.0006, r = -0.46). Furthermore, treatment with a HMG-CoA reductase inhibitor or acetylsalicylic acid showed reduced levels of IL-21, IL-23 and VCAM1 (all p < 0.05), but did not influence IL-17A. The association of IL-17A with ischemic symptoms and vulnerable plaque characteristics suggests that the pro-inflammatory cytokine IL-17A may contribute to atherosclerosis und plaque instability.

Interleukin-10 microsatellite variants and the risk of acute coronary syndrome among Tunisians

The objective of the study was to investigate the association of interleukin (IL)-10 promoter microsatellite polymorphisms, linked with altered IL-10 secretion, with the susceptibility to acute coronary syndrome (ACS) in adult Tunisian patients. We genotyped 291 ACS patients and 291 age-, gender- and ethnically matched control subjects for the microsatellites IL-10R [X78437.2g.5325CA(11_15)] and IL-10G [X78437.2g.8134CA(14_29)] by PCR-based assays. Haplotypes were reconstructed using maximum likelihood method. Regression analysis was used in determining the risk imparted by specific IL-10 genotypes and haplotypes. A significant decrease in IL-10G12 (24 CA repeats) (P<0.001; OR=0.465) and IL-10G15 (27 CA repeats) (P=0.043; OR=0.232), and a significant increase in the low IL-10 producer allele, IL-10R3 (14 CA repeats) (P=0.049; OR=1.461), microsatellites were seen in the ACS group compared with controls. Of the possible 14 haplotypes constructed, there was an enrichment of the R2G9 (13CA vs. 21CA) haplotype in controls [P=0.019; adjusted OR (95% CI)=0.67 (0.48-0.94)] and R2G15 (13CA vs. 27CA) haplotype in cases [P=0.042; adjusted OR (95% CI)=5.29 (1.06-26.30)], thus assigning a protective and susceptible nature to these haplotypes respectively. The differential association of IL-10 microsatellite alleles and haplotypes with ACS suggests that IL-10 contributes to ACS pathogenesis. While the functional attributes of these microsatellite markers remain to be seen, it is likely that they have distinct functional properties (altered IL-10 secretion), which in turn affect the susceptibility to ACS development.

Egr-1 deficiency in bone marrow-derived cells reduces atherosclerotic lesion formation in a hyperlipidaemic mouse model

AIMS

Early growth response gene-1 (Egr-1) regulates the expression of genes important to cardiovascular disease. Within atherosclerotic lesions, Egr-1 is expressed in smooth muscle cells, endothelial cells, and macrophages. Since macrophages play a pivotal role in atherosclerotic lesion initiation and progression, this study investigated the effects of Egr-1 deficiency within bone marrow-derived cells on the development of atherosclerosis in a hyperlipidaemic mouse model.

METHODS AND RESULTS

Bone marrow from Egr-1-deficient mice and wild-type controls was transplanted into lethally irradiated LDL receptor null mice. After 26 weeks on a high fat diet, atherosclerotic lesion size within the aortic sinus of recipients was evaluated. Mice receiving Egr-1-deficient bone marrow had significantly decreased lesion size compared with controls. Lesions of these mice contained fewer macrophages and had reduced expression of vascular cell adhesion molecule-1 (VCAM-1), tissue factor, as well as transforming growth factor receptor type II, which are target genes of Egr-1. These results were validated by in vitro analysis of Egr-1-deficient peritoneal macrophages which, after lipopolysaccharide stimulation, had decreased VCAM-1 and tissue factor mRNA expression compared with wild-type controls.

CONCLUSION

This study demonstrates that bone marrow-derived Egr-1 promotes macrophage accumulation, atherosclerotic lesion development, and lesion complexity.

Rapamycin enhances LPS induction of tissue factor and tumor necrosis factor-alpha expression in macrophages by reducing IL-10 expression

Bacterial lipopolysaccharide (LPS) induces monocytes/macrophages to express proinflammatory cytokines and tissue factor (TF), the primary activator of the coagulation cascade. Anti-inflammatory signaling pathways including the phosphatidylinositol-3-kinase (PI3K)-Akt pathway inhibit proinflammatory and TF gene expression in macrophages. We determined the role of Akt, the mammalian target of rapamycin (mTOR) and interleukin-10 in the inhibition of LPS-induced proinflammatory cytokine and TF gene expression in peritoneal macrophages (PMs). We used wild type (WT) peritoneal macrophages (PMs), and PMs from PTEN(flox/flox)/LysMCre mice (PTEN(-/-) PMs), which have increased Akt activity. Pharmacologic inhibition of mTOR with rapamycin inhibited LPS induction of IL-10 mRNA and protein, and enhanced the expression of TF and the proinflammatory cytokine TNFalpha in WT PMs. Furthermore, neutralizing IL-10 with anti-IL-10 antibody enhanced LPS induction of TNFalpha and TF expression in WT PMs. The addition of recombinant IL-10 abolished rapamycin enhancement of LPS-induced TNFalpha and TF expression in WT PMs. Consistent with enhanced Akt activation, LPS-induced IL-10 expression was increased in PTEN(-/-) PMs compared to WT PMs. In contrast, LPS-induced TNFalpha and TF expression was significantly reduced in PTEN(-/-) PMs compared to WT PMs. However, the neutralizing IL-10 antibody did not completely prevent inhibition of LPS-induced TNFalpha and TF expression in PTEN(-/-) PMs. The results indicate that mTOR dependent IL-10 expression leads to inhibition of LPS induction of TF and the proinflammatory cytokine TNFalpha in WT macrophages. In contrast, the decrease in LPS-induced TNFalpha and TF expression in PTEN(-/-) PMs also requires an IL-10-independent pathway.

Vasoactive Intestinal Peptide and pituary adenylate cyclase-activating polypeptide inhibit tissue factor expression in monocyte in vitro and in vivo

Tissue factor (TF), which is expressed on the surface of activated monocytes, is the major procoagulant that initiates thrombus formation in sepsis. Two endogenous neuropeptides, vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP), are attractive candidates for the development of therapies against septic shock. The purpose of this study was to examine whether VIP or PACAP inhibit the LPS-induced TF expression in monocytes. Treatment of freshly isolated human monocytes or cultured monocytic THP-1 cells with VIP or PACAP leads to reduced LPS-induced TF protein, mRNA expression and activity, as demonstrated by Western blot, real-time polymerase chain reaction, and TF activity assay, respectively. In an endotoxemic model, VIP blunts the increase of LPS-induced TF expression in blood cells at the transcriptional level, as demonstrated by real-time polymerase chain reaction. However, neither neuropeptide affects the expression of TF pathway inhibitor in monocytes. In vitro, LPS increases the migration of c-Rel/p65 into the nucleus and the phosphorylation of p38 and JNK, all of which are essential for LPS-induced TF expression. In addition, interestingly, VIP and PACAP block both the migration of c-Rel/p65 and the phosphorylation of p38 and JNK, as demonstrated by Western blot analysis. These data indicate that VIP and PACAP inhibit LPS-induced TF expression in monocytes in vitro and in vivo, confirming these peptides as candidates for the multitarget therapy of septic shock.

Posttranscriptional regulation of interleukin-10 expression by hsa-miR-106a

IL-10 is a key regulator of the immune system that critically determines health and disease. Its expression is finely tuned both at the transcriptional and posttranscriptional levels. Although the importance of posttranscriptional regulation of IL-10 has been previously shown, understanding the underlying mechanisms is still in its infancy. In this study, using a combination of bioinformatics and molecular approaches, we report that microRNA (hsa-miR-106a) regulates IL-10 expression. The hsa-miR-106a binding site in the 3' UTR of IL10 has been identified by site-directed mutagenesis studies. Also, the involvement of transcription factors, Sp1 and Egr1, in the regulation of hsa-miR-106a expression and concomitant decrease in the IL-10 expression, has also been demonstrated. In summary, our results showed that IL-10 expression may be regulated by miR-106a, which is in turn transcriptionally regulated by Egr1 and Sp1.

Human tribbles homologue 2 is expressed in unstable regions of carotid plaques and regulates macrophage IL-10 in vitro

Mammalian orthologues of the Drosophila tribbles protein (Trb1, Trb2 and Trb3) are a recently described family of signalling molecules that regulate gene expression by modulation of protein kinase signalling pathways. In the present study, a screen for mRNA species specifically regulated in vulnerable regions of human atherosclerotic plaque demonstrated the up-regulation of both Trb1 and Trb2, the latter by more than 8-fold. In vitro experiments in primary human monocyte-derived macrophages showed that Trb2 expression was up-regulated by treatment with oxidized LDL (low-density lipoprotein), and that expression of recombinant Trb2 specifically reduced macrophage levels of IL-10 (interleukin-10) mRNA. Our results thus identify Trb2 as a highly regulated gene in vulnerable atherosclerotic lesions, and demonstrate inhibition of macrophage IL-10 biosynthesis as a potential pro-inflammatory consequence of high Trb2 expression, which may contribute to plaque instability.

Interleukin 10 gene promoter polymorphisms in women with pregnancy loss: preferential association with embryonic wastage

Interleukin 10 (IL10) is associated with maternal immunotolerance. IL10 also down-regulates decidual cell tissue factor expression, the main molecule triggering coagulation activation: this antithrombotic effect may protect the umbilicoplacental vasculature from the 10th wk of gestation onward. IL10 down-regulation may thus dispose to early pregnancy loss (PL) due to maternal immunotolerance defect or late pregnancy failure due to placental vascular insufficiency. IL10 gene promoter polymorphisms associated with cytokine down-regulation may help to identify the actual and probable mechanisms of IL10 modulation in pregnancy outcomes. We investigated the following four IL10 promoter polymorphisms associated with IL10 down-regulation: two single-nucleotide polymorphisms rs1800871 and rs1800872 and two polymorphic CA repeat microsatellites IL10 X78437.2:g8134CA(14_29) and IL10 X78437.2:g.5325CA(11_15). Each microsatellite was analyzed as a biallelic polymorphism. Based on a review of the literature, we define a short allele and a long allele for each microsatellite. We compared their frequencies in early PL occurring before 10 wk of amenorrhea (n = 342) and in PL occurring later on (n = 123). The mutated alleles rs1800871T (odds ratio, 3.083; 95% confidence interval, 1.984-4.792) and rs1800872A (odds ratio, 3.013; 95% confidence interval, 1.924-4.719) were associated with early PL. The haplotype rs1800872A/rs1800871T/X78437.2:g.8134CA[14_25]/X78437.2:g.5325CA[11_13], which includes the two mutated alleles, was significantly associated with the risk of early PL in a dose-dependent manner. Positivity for one haplotype was significantly associated with a 5.6-fold increase in the risk of early pregnancy failure, and positivity for two haplotypes was associated with an 8-fold increase in risk. In women with PL, some polymorphisms of the IL10 gene promoter seem to be constitutional risk factors for early (embryonic) pregnancy failure.

The role of endothelial cell biology in endocarditis

The treatment of endocarditis remains a challenge for physicians, even in times of modern antibiotic treatment. Depending on its cause, endocarditis can either be of infectious or non-infectious origin. Infective endocarditis is caused by bacterial (or fungal) pathogens, and the clinical course is critically dependent on the virulence factors of the specific microorganisms involved. Therefore, the clinical type of endocarditis can be divided into an acute and more aggressive form and a subacute form (endocarditis lenta). Much of our knowledge regarding the pathogenesis of infective endocarditis is based on studies of the virulence of Staphylococcus aureus, which has become the most frequent cause of infective endocarditis nowadays. However, independently of the underlying cause of endocarditis (infectious or noninfectious), the pathogenesis involves the damage and disturbance of endothelial function and the formation of associated "vegetation". Surprisingly little is known about the specific role of the endothelium in the pathogenesis of endocarditis. This review will thus give insights into current knowledge of the pathogenesis of endocarditis with a focus on the role of the endothelium.

Reduced nicotinamide adenine dinucleotide phosphate oxidase-independent resistance to Aspergillus fumigatus in alveolar macrophages

The fungal pathogen Aspergillus fumigatus is responsible for increasing numbers of fatal infections in immune-compromised humans. Alveolar macrophages (AM) are important in the innate defense against aspergillosis, but little is known about their molecular responses to fungal conidia in vivo. We examined transcriptional changes and superoxide release by AM from C57BL/6 and gp91(phox)(-/-) mice in response to conidia. Following introduction of conidia into the lung, microarray analysis of AM showed the transcripts most strongly up-regulated in vivo to encode chemokines and additional genes that play a critical role in neutrophil and monocyte recruitment, indicating that activation of phagocytes represents a critical early response of AM to fungal conidia. Of the 73 AM genes showing > or = 2-fold changes, 8 were also increased in gp91(phox)(-/-) mice by conidia and in C57BL/6 mice by polystyrene beads, suggesting a common innate response to particulate matter. Ingenuity analysis of the microarray data from C57BL/6 mice revealed immune cell signaling and gene expression as primary mechanisms of this response. Despite the well-established importance of phagocyte NADPH oxidase in resisting aspergillosis, we found no evidence of this mechanism in AM following introduction of conidia into the mouse lung using transcriptional, luminometry, or NBT staining analysis. In support of these findings, we observed that AM from C57BL/6 and gp91(phox)(-/-) mice inhibit conidial germination equally in vitro. Our results indicate that early transcription in mouse AM exposed to conidia in vivo targets neutrophil recruitment, and that NADPH oxidase-independent mechanisms in AM contribute to inhibition of conidial germination.

Single-stranded polyinosinic acid oligonucleotides trigger leukocyte production of proteins belonging to fibrinolytic and coagulation cascades

The present study assessed the inductory effects of ds- and ssRNA on the leukocyte production of proteins belonging to fibrinolytic and coagulation cascades. Murine splenocytes were stimulated with dsRNA [polyinosinic:polycytidylic acid (polyIC)] and ssRNA sequences [polyinosinic acid (polyI), polycytidylic acid (polyC), and polyuridylic acid (polyU)]. The expression of plasminogen (Plg), tissue factor (TF), IL-6, and IFN-alpha was assessed. Intracellular transduction mechanisms activated by oligonucleotides were evaluated using specific inhibitors of signaling pathways and genetically modified mice. polyIC efficiently and dose-dependently induced the expression of Plg, IL-6, and IFN-alpha, whereas TF was not induced by polyIC. polyI was unable to trigger IFN-alpha production, and it was efficiently inducing Plg and TF. IFN-alphaR and dsRNA-dependent protein kinase signaling were not required for the polyI-induced production of Plg or TF. Neither polyU nor polyC induced the expression of Plg or TF. Importantly, the presence of U- and C-nucleotide strands in the dsRNA significantly reduced expression of Plg and TF compared with polyI alone. Exposure of splenocytes to polyI activated the NF-kappaB pathway followed by the expression of TF and IL-6. In contrast, Plg production did not require NF-kappaB, was only partly down-regulated by p38 MAPK inhibitor, and was efficiently inhibited by insulin, indicating a different mechanism for its induction. ssRNA exerts its TF-generating properties through NF-kappaB activation in an IFN-alpha-independent manner. The expression of fibrinolytic versus coagulation proteins is regulated through distinctly different transduction pathways. As fibrinolytic and coagulation cascades are important components of inflammatory homeostasis, these findings might have importance for development of new, targeted therapies.

Tissue factor and IL8 production by P-selectin-dependent platelet-monocyte aggregates in whole blood involves phosphorylation of Lyn and is inhibited by IL10

BACKGROUND

P-selectin and CD40L expressed by activated platelets induce tissue factor (TF) and inflammatory cytokines in monocytes, but little is known of the cellular signaling pathways involved. The anti-inflammatory cytokine IL10 reduces atherosclerotic plaque formation.

OBJECTIVES

To evaluate the importance of P-selectin upon platelet-monocyte aggregate (PMA) formation in thrombin receptor activator peptide (TRAP) stimulated whole blood, the P-selectin-P-selectin glycoprotein ligand (PSGL)-1-induced cellular signaling pathway, and the effects of IL10 on these functions.

METHODS

TF, IL8, and monocyte chemotactic protein-1 (MCP-1) production, PMAs and phosphorylation of Lyn were analyzed in whole blood, purified monocytes, and vitamin D(3)-differentiated U-937 cells stimulated with TRAP or P-selectin with or without IL10. Anti-P-selectin or anti-CD40L antibodies (Abs), Src-kinases inhibitors, SU6656 or PP2, were added in some experiments.

RESULTS

TRAP and P-selectin increased TF, IL8, and MCP-1 mRNA in whole blood and purified monocytes. Anti-P-selectin Ab reduced TRAP-induced PMA formation by 80 +/- 2% (P = 0.001) and production of TF (P = 0.04) and IL8 (P = 0.01). IL10 and SU6656 had no effect on PMA formation, although both significantly reduced TF (P = 0.002 and P = 0.02) and IL8 (P = 0.009 and P = 0.001) mRNA upon TRAP and P-selectin stimulation. Induced Lyn phosphorylation in monocytes was diminished by SU6656 (P = 0.02), anti-P-selectin Ab (P = 0.02), and IL10 (P = 0.03) upon TRAP or P-selectin stimulation. These results were confirmed in the vitamin D(3)-differentiated U-937 cells.

CONCLUSIONS

The formation of PMAs in whole blood was P-selectin-dependent in the long term. P-selectin-PSGL-1-induced TF and IL8 expression through Lyn phosphorylation, and part of the inhibitory effect of IL10 depends on reduced phosphorylation.

Prostaglandin E receptor type 4-associated protein interacts directly with NF-kappaB1 and attenuates macrophage activation

Macrophage activation participates pivotally in the pathophysiology of chronic inflammatory diseases, including atherosclerosis. Through the receptor EP4, prostaglandin E(2) (PGE(2)) exerts an anti-inflammatory action in macrophages, suppressing stimulus-induced expression of certain proinflammatory genes, including chemokines. We recently identified a novel EP4 receptor-associated protein (EPRAP), whose function in PGE(2)-mediated anti-inflammation remains undefined. Here we demonstrate that PGE(2) pretreatment selectively inhibits lipopolysaccharide (LPS)-induced nuclear factor kappaB1 (NF-kappaB1) p105 phosphorylation and degradation in mouse bone marrow-derived macrophages through EP4-dependent mechanisms. Similarly, directed EPRAP expression in RAW264.7 cells suppresses LPS-induced p105 phosphorylation and degradation, and subsequent activation of mitogen-activated protein kinase kinase 1/2. Forced expression of EPRAP also inhibits NF-kappaB activation induced by various proinflammatory stimuli in a concentration-dependent manner. In co-transfected cells, EPRAP, which contains multiple ankyrin repeat motifs, directly interacts with NF-kappaB1 p105/p50 and forms a complex with EP4. In EP4-overexpressing cells, PGE(2) enhances the protective action of EPRAP against stimulus-induced p105 phosphorylation, whereas EPRAP silencing in RAW264.7 cells impairs the inhibitory effect of PGE(2)-EP4 signaling on LPS-induced p105 phosphorylation. Additionally, EPRAP knockdown as well as deficiency of NF-kappaB1 in macrophages attenuates the inhibitory effect of PGE(2) on LPS-induced MIP-1beta production. Thus, PGE(2)-EP4 signaling augments NF-kappaB1 p105 protein stability through EPRAP after proinflammatory stimulation, limiting macrophage activation.

[Clinical usefulness of plasma interleukin-6 and interleukin-10 in disseminated intravascular coagulation]

BACKGROUND

Disseminated intravascular coagulation (DIC) is a syndrome characterized by a systemic activation of coagulation leading to the intravascular deposition of fibrin and the simultaneous consumption of coagulation factors and platelets. Inflammatory cytokines can activate the coagulation system. This study investigated the diagnostic and prognostic usefulness of the plasma level of interleukin-6 (IL-6) and interleukin-10 (IL-10) for predicting DIC.

METHODS

The study populations were 15 healthy controls and 81 patients who were clinically suspected of having DIC and were requested to perform DIC battery tests. The presence of overt DIC was defined by the International Society on Thrombosis and Haemostasis Subcommittee cumulative score of 5 or above. The 28 day mortality was used to assess the prognostic outcome. The plasma levels of the cytokines were measured by ELISA.

RESULTS

The plasma levels of IL-6 and IL-10 in patients (N=81) were higher than those of control (N=15). IL-6 and IL-10 levels of overt DIC group (N=31) were 3 times and 1.5 times higher than those, respectively, of non-overt DIC group (N=50). In infection group (N=48), IL-6 and IL-10 levels of overt DIC group (N=18) were 5 times and 3 times higher than those, respectively, of non-overt DIC group (N=30). The diagnostic efficiency of IL-6 (optimal cut off >40.4 pg/mL) and IL-10 (>9.7 pg/mL) for the diagnosis of overt DIC were 67% and 69%, respectively, which were similar to that of D-dimer. Plasma levels of IL-6 and IL-10 were also higher in non-survivors than in survivors. The patients with higher levels of IL-6 and IL-10 showed a poorer prognosis.

CONCLUSIONS

The proinflammatory cytokine, IL-6 and anti-inflammatory cytokine, IL-10 were useful for the diagnosis of overt DIC and the prediction of its prognosis. These results also showed the evidence of a close interaction between coagulation and inflammation.

Sphingosine-1-Phosphate Analogue FTY720 Causes Lymphocyte Redistribution and Hypercholesterolemia in ApoE-Deficient Mice

Objective— Resident immune cells are a hallmark of atherosclerotic lesions. The sphingolipid analogue drug FTY720 mediates retrafficking of immune cells and inhibits their homing to inflammatory sites. We have evaluated the effect of FTY720 on atherogenesis and lipid metabolism.

Methods and Results— ApoE −/− mice on a normal laboratory diet received oral FTY720 for 12 weeks, which led to a 2.4-fold increase in serum cholesterol (largely VLDL fraction) and a 1.8-fold increase in hepatic HMGCoA reductase mRNA. FTY720 increased plasma sphingosine-1-phosphate and induced marked peripheral blood lymphopenia. A discoordinate modulation of B, T and monocyte cell numbers was found in peripheral lymphoid organs. Overall depletion of T cells was accompanied by a relative (2-fold) increase in regulatory T cell content paralleled by a similar increase in effector memory T cells (CD4+CD44hiCD62lo) as absolute numbers of both subpopulations remained essentially unchanged. Lymphocyte function was unaltered as indicated by anti-OxLDL antibodies and T cell proliferation. There were no changes in atherosclerotic lesions in early and established atherosclerosis.

Conclusions— FTY720 mediated peripheral lymphocyte depletion and retrafficking without altering function and overall balance of pro- and antiatherogenic lymphocyte populations. A net decrease in lymphocyte numbers occurred concomitantly with a more proatherogenic hypercholesterolemia resulting in unaltered atherogenesis.

Inhibitory effect of 1,8-cineol (eucalyptol) on Egr-1 expression in lipopolysaccharide-stimulated THP-1 cells

AIM

To study the effects of 1,8-cineol (eucalyptol) on the expression of early growth response factor-1 (Egr-1) and NF-kappaB in the human monocyte THP-1 cell line stimulated by lipopolysaccharide (LPS).

METHODS

The THP-1 cells were incubated with serial doses of 1,8-cineol (1, 10, and 100 mg/L, 30 min) before being stimulated with LPS (1 mg/L, 30 min). The localization of Egr-1 in the THP-1 cells was detected by immunofluorescence and a laser scanning confocal microscope. The expression of Egr-1 in the nuclei and whole cell, and NF-kappaB in the nuclei, were measured by Western blot analysis.

RESULTS

When stimulated by LPS, the FITC-labeled Egr-1 was detected mainly in the nuclei. Moreover, the expression of Egr-1 in the whole cell increased markedly compared with the control cells. 1,8-Cineol pretreatment decreased the expression of Egr-1 in both the nuclei and whole cell of the LPS-stimulated THP-1 cells, and this effect was concentration-dependent, but there was no reaction on the expression of NF-kappaB in the nuclei protein in the LPS-stimulated THP-1 cells.

CONCLUSION

In a concentration-dependent manner, 1,8-Cineol reduces LPS-induced Egr-1 expression in nuclei and in whole cell of THP-1 cells, but shows no effect on NF-kappaB expression.

Lipopolysaccharide down-regulates the thrombomodulin expression of peripheral blood monocytes: effect of serum on thrombomodulin expression in the THP-1 monocytic cell line

Thrombomodulin has a central role in the regulation of coagulation through its abilities to promote generation of the potent anticoagulant activated protein C. Because little is known about monocyte thrombomodulin expression and its regulatory mechanism by lipopolysaccharide, we investigated the effect of lipopolysaccharide on monocyte's thrombomodulin expression. Lipopolysaccharide reduced the surface thrombomodulin expression of human peripheral blood monocytes in a dose-dependent and time-dependent manner, regardless of the addition of serum. The surface thrombomodulin activity was comparably decreased in monocytes incubated with lipopolysaccharide. Blocking nuclear factor-kappaB by MG132 or aurine tricarboxylic acid effectively inhibited the lipopolysaccharide-induced surface thrombomodulin down-regulation of monocytes. Lipopolysaccharide inactivation by polymyxin B in the supernatants from the lipopolysaccharide-stimulated cultures still reduced the surface thrombomodulin expression of monocytes, suggesting a role for soluble mediators in the down-regulation of thrombomodulin. The lipopolysaccharide-induced thrombomodulin surface expression and the mRNA levels of the monocytic leukemic cell line (THP-1) were decreased in serum-depleted culture, while they were increased in medium containing 10% serum. We conclude that lipopolysaccharide down-regulates the thrombomodulin expression of monocytes and that nuclear factor-kappaB is a critical mediator of the repression of thrombomodulin by lipopolysaccharide. Regulation of the THP-1 thrombomodulin expression by lipopolysaccharide depends on the presence of serum.

Cell adhesion on nanofibrous polytetrafluoroethylene (nPTFE)

Here, we described the in vitro biocompatibility of a novel nanostructured surface composed of PTFE as a potential polymer for the prevention of adverse host reactions to implanted devices. The foreign body response is characterized at the tissue-material interface by several layers of macrophages and large multinucleated cells known as foreign body giant cells (FBGC), and a fibrous capsule. The nanofibers of nanofibrous PTFE (nPTFE) range in size from 20 to 30 nm in width and 3-4 mm in length. Glass surfaces coated with nPTFE (produced by jet-blowing of PTFE 601A) were tested under in vitro conditions to characterize the amount of protein adsorption, cell adhesion, and cell viability. We have shown that nPTFE adsorbs 495 +/- 100 ng of bovine serum albumin (BSA) per cm2. This level was considerably higher than planar PTFE, most likely due to the increase in hydrophobicity and available surface area, both a result of the nanoarchitecture. Endothelial cells and macrophages were used to determine the degree of cell adsorption on the surface of the nanostructured polymer. Both cell types were significantly more round and occupied less area on nPTFE as compared to tissue culture polystyrene (TCPS). Furthermore, a larger majority of the cells on the nPTFE were dead compared to TCPS, at dead-to-live ratios of 778 +/- 271 to 1 and 23 +/- 5.6 to 1, respectively. Since there was a high amount of cell death (due to either apoptosis or necrosis), and the foreign body response is a form of chronic inflammation, an 18 cytokine Luminex panel was performed on the supernatant from macrophages adherent on nPTFE and TCPS. As a positive control for inflammation, lipopolysaccharide (LPS) was added to macrophages on TCPS to estimate the maximum inflammation response of the macrophages. From the data presented with respect to IL-1, TNF-alpha, IFN-gamma, and IL-5, we concluded that nPTFE is nonimmunogenic and should not yield a huge inflammatory response in vivo, and cell death observed on the surface of nPTFE was likely due to apoptosis resulting from the inability of cells to spread on these surface. On the basis of the production of IL-1, IL-6, IL-4, and GM-CSF, we concluded that FBGC formation on nPTFE may be decreased as compared to materials known to elicit FBGC formation in vivo.

IL-10-induced TNF-alpha mRNA destabilization is mediated via IL-10 suppression of p38 MAP kinase activation and inhibition of HuR expression

Inflammation plays an essential role in vascular injury and repair. Mononuclear phagocytes are important contributors in these processes, in part, via adhesive interactions and secretion of proinflammatory cytokines. The antiinflammatory cytokine interleukin (IL)-10 suppresses such responses via deactivation of monocytes/macrophages and repression of inflammatory cytokine expression. The mechanisms of IL-10's suppressive action are, however, incompletely characterized. Here, we report that systemic IL-10 treatment after carotid artery denudation in mice blunts inflammatory cell infiltration and arterial tumor necrosis factor (TNF) expression. At the molecular level, in a human monocytic cell line, U937 IL-10 suppressed LPS-induced mRNA expression of a number of inflammatory cytokines, mainly via posttranscriptional mRNA destabilization. Detailed studies on IL-10 regulation of TNF-alpha mRNA expression identified AU-rich elements (ARE) in the 3' untranslated region as a necessary determinant of IL-10-mediated TNF-alpha mRNA destabilization. IL-10 sensitivity to TNF depends on the ability of IL-10 to inhibit the expression and mRNA-stabilizing protein HuR and via IL-10 mediated repression of p38 mitogen-activated protein (MAP) kinase activation. Because IL-10 function and signaling are important components for control of inflammatory responses, these results may provide insights necessary to develop strategies for modulating vascular repair and other accelerated arteriopathies, including transplant vasculopathy and vein graft hyperplasia.

Anti-inflammatory effect of roasted licorice extracts on lipopolysaccharide-induced inflammatory responses in murine macrophages

Licorice, the roots of Glycyrrhiza inflata, is used by practitioners of alternative medicine to treat individuals with gastric or duodenal ulcers, bronchitis, cough, arthritis, adrenal insufficiency, and allergies. We investigated the anti-inflammatory properties of 4 licorice extracts: extracts of roasted licorice obtained by ethanol (rLE) or water extraction (rLW) and extracts of raw licorice obtained by ethanol (LE) or water extraction (LW). rLE demonstrated strong anti-inflammatory activity through its ability to reduce nitric oxide and prostaglandin E(2) production in the LPS-stimulated mouse macrophage cell, RAW264.7. It also inhibited the production of pro-inflammatory cytokines and CD14 expression on the LPS-stimulated RAW264.7 cells. Further study indicated that LPS-induced degradation and phosphorylation of Ikappa-Balpha, along with DNA-binding of NF-kappaB, was significantly inhibited by rLE exposure in RAW264.7 cells. In the murine model, we found that in vivo exposure to rLE-induced an increase in the survival rate, reduced plasma levels of TNF-alpha and IL-6, and increased IL-10 production in LPS-treated mice. Collectively, these data suggest that the use of rLE may be a useful therapeutic approach to various inflammatory diseases.

Actualización en cardiopatía isquémica 2005

This article is a review of the main developments in acute coronary syndromes reported in publications and conference presentations in 2005. It covers the pathophysiology, secondary prevention, prognosis, and treatment of ST-segment elevation and non-ST-segment elevation acute coronary syndromes, and the latest clinical practice guidelines.