Immune Checkpoint Inhibitor-Induced Thyroiditis Is Associated with Increased Intrathyroidal T Lymphocyte Subpopulations

Background: Immune checkpoint inhibitors (ICIs) frequently cause thyroid dysfunction but their underlying mechanism remains unclear. We have previously demonstrated increased circulating natural killer (NK) cells and human leukocyte antigen (HLA)-DR surface expression on inflammatory intermediate CD14⁺CD16⁺ monocytes in programmed cell death protein-1 (PD-1) inhibitor-treated patients. This study characterizes intrathyroidal and circulating immune cells and class II HLA in ICI-induced thyroiditis. Methods: This is a single-center prospective cohort study of 10 patients with ICI-induced thyroiditis by flow cytometry of thyroid fine needle aspirates (n = 9) and peripheral blood (n = 7) as compared with healthy thyroid samples (n = 5) and healthy volunteer blood samples (n = 44); HLA class II was tested in n = 9. Results: ICI-induced thyroiditis samples demonstrated overall increased T lymphocytes (61.3% vs. 20.1%, p = 0.00006), CD4^-CD8^- T lymphocytes (1.9% vs. 0.7%, p = 0.006), and, as a percent of T lymphocytes, increased CD8⁺T lymphocytes (38.6% vs. 25.7%; p = 0.0259) as compared with healthy thyroid samples. PD-1 inhibitor-induced thyroiditis had increased CD4⁺PD1⁺ T lymphocytes (40.4% vs. 0.8%; p = 0.021) and CD8⁺PD1⁺ T lymphocytes (28.8% vs. 1.5%; p = 0.038) in the thyroid compared with the blood. Circulating NK cells, certain T lymphocytes (CD4⁺CD8⁺, CD4^-CD8^- T, gamma-delta), and intermediate monocytes were increased in ICI-induced thyroiditis. Six patients typed as HLA-DR4-DR53 and three as HLA-DR15. Conclusions: ICI-induced thyroiditis is a T lymphocyte-mediated process with intra-thyroidal predominance of CD8⁺ and CD4^-CD8^- T lymphocytes. The HLA haplotypes may be involved but need further evaluation. These findings expand the limited understanding of ICI-induced thyroiditis, which could be further translated to guide immunomodulatory therapies for advanced thyroid cancer.

CD14+CD16+ monocytes in coronary artery disease and their relationship to serum TNF-α levels

Monocytes play a central role in the inflammatory disease atherosclerosis. CD14+CD16+ monocytes are considered proinflammatory monocytes, as they have an increased capacity to produce proinflammatory cytokines, such as TNF-α, and are elevated in various inflammatory diseases. We hypothesized that patients with coronary artery disease (CAD) have increased levels of CD14+CD16+ monocytes, and that CD14+CD16+ monocytes are associated with inflammation markers. We investigated CD14+CD16+ monocytes in 247 patients with CAD and 61 control subjects using flow cytometry. In addition serum concentrations of TNF-α, IL-6, and Hs-CRP were assessed. Patients with CAD had higher levels of CD14+CD16+ monocytes than controls (13.6% versus 11.4%; p<0.001). Logistic regression analysis including quartiles of CD14+CD16+ monocytes showed that CD14+CD16+ monocytes were associated with prevalence of CAD (OR 4.9, 95% CI 2.5–19.1, for subjects in the fourth quartile in comparison to subjects in the first quartile). The association between CD14+CD16+ monocytes and CAD remained independently significant after adjustment for most potential confounders (OR 5.0, 95% CI 1.2-20.0). Serum concentrations of TNF-α were elevated in subjects within the highest quartiles of CD14+CD16+ monocytes (p=0.018). Our study showed that increased numbers of CD14+CD16+ monocytes are associated with coronary atherosclerosis and TNF-α. In accordance, recent animal studies suggest a possibly important role of these monocytes in the development of atherosclerosis.

The effect of alcohol on the differential expression of cluster of differentiation 14 gene, associated pathways, and genetic network

Alcohol consumption affects human health in part by compromising the immune system. In this study, we examined the expression of the Cd14 (cluster of differentiation 14) gene, which is involved in the immune system through a proinflammatory cascade. Expression was evaluated in BXD mice treated with saline or acute 1.8 g/kg i.p. ethanol (12.5% v/v). Hippocampal gene expression data were generated to examine differential expression and to perform systems genetics analyses. The Cd14 gene expression showed significant changes among the BXD strains after ethanol treatment, and eQTL mapping revealed that Cd14 is a cis-regulated gene. We also identified eighteen ethanol-related phenotypes correlated with Cd14 expression related to either ethanol responses or ethanol consumption. Pathway analysis was performed to identify possible biological pathways involved in the response to ethanol and Cd14. We also constructed a genetic network for Cd14 using the top 20 correlated genes and present several genes possibly involved in Cd14 and ethanol responses based on differential gene expression. In conclusion, we found Cd14, along with several other genes and pathways, to be involved in ethanol responses in the hippocampus, such as increased susceptibility to lipopolysaccharides and neuroinflammation.

GM-CSF Down-Regulates TLR Expression via the Transcription Factor PU.1 in Human Monocytes

Toll-like receptors (TLR) are crucial sensors of microbial agents such as bacterial or viral compounds. These receptors constitute key players in the induction of inflammation, e.g. in septic or chronic inflammatory diseases. Colony-stimulating factors (CSFs) such as granulocyte-macrophage-CSF (GM-CSF) or granulocyte-CSF (G-CSF) have been extensively investigated in their capacity to promote myelopoiesis in febrile neutropenia or to overcome immunosuppression in patients suffering from sepsis-associated neutropenia or from monocytic immunoincompetence. We report here that GM-CSF, downregulates TLR1, TLR2 and TLR4 in a time- and dose-dependent fashion in human monocytes. Diminished pathogen recognition receptor expression was accompanied by reduced downstream p38 and extracellular-signal-regulated kinase (ERK) signaling upon lipoteichoic acid (LTA) and lipopolysaccharide (LPS) binding-and accordingly led to impaired proinflammatory cytokine production. Knockdown experiments of the transcription factors PU.1 and VentX showed that GM-CSF driven effects on TLR regulation is entirely PU.1 but not VentX dependent. We further analysed monocyte TLR and CD14 expression upon exposure to the IMID® immunomodulatory drug Pomalidomide (CC-4047), a Thalidomide analogue known to downregulate PU.1. Indeed, Pomalidomide in part reversed the GM-CSF-mediated effects. Our data indicate a critical role of PU.1 in the regulation of TLR1, 2, 4 and of CD14, thus targeting PU.1 ultimately results in TLR modulation. The PU.1 mediated immunomodulatory properties of GM-CSF should be taken into consideration upon usage of GM-CSF in inflammatory or infection-related conditions.

Toll-like receptor 2 ligand, lipoteichoic acid is inhibitory against infectious laryngotracheitis virus infection in vitro and in vivo

Lipoteichoic acid (LTA) is one of the pathogen associated molecular patterns (PAMPs) that activates toll-like receptor (TLR)2-cluster of differentiation (CD)14 signalling pathway. This recognition elicits antiviral responses that have been recorded against viruses of mammals although such responses have not been characterized adequately against avian viruses. In this investigation, we characterized the LTA induced antiviral responses against infectious laryntotracheitis virus (ILTV) infection in vitro and in vivo. We found that LTA is capable of up regulating mRNA expression of innate proteins in macrophages such as MyD88, iNOS and IL-1β and reduces the ILTV plaques in vitro. Similarly, we found that LTA treatment of embryonic day 18 (ED18) eggs can lead to the antiviral response against pre-hatch ILTV infection in vivo and is associated with expansion of macrophage populations and expression of IL-1β and MyD88 in the lung. The data highlight that LTA can be a potential innate immune stimulant that can be used against ILTV infection in chickens.

Role of the exogenous HCV core protein in the interaction of human hepatocyte proliferation and macrophage sub-populations

BACKGROUND

The core protein of hepatitis C virus (HCV) is found in the cytoplasm and nuclei of infected cells, including hepatocytes and other cells in the liver. The core protein could be secreted as well. Resident liver macrophages are dependent on the tissue micro-environment and external stimuli to differentiate M1 and M2 hypotypes with distinct functions, and increased expression of the nuclear transcription factor STAT3 was seen in M2-polarized macrophages. In contrast to proinflammatory M1 macrophages, M2 macrophages serve beneficial roles in chronic inflammation, immunosuppression, and tumorigenesis.

METHODS

Monocyte-derived human macrophage line (mTHP-1) was treated with the exogenous HCV core protein. Next, the mTHP-1 culture supernatant or cell pellets were added to culture media of normal human liver cell line (L02).

RESULTS

Only the culture supernatant stimulated L02 cells proliferation, which was associated with phosphorylated ERK expression. Core protein activated mTHP-1 cells showed enhanced pro- and anti-inflammatory cytokines secretion, which was accompanied by high expression of phosphorylated NF-κB105 and NF-κB65. However, phosphorylated STAT1, and STAT3, which are normally associated with M1 and M2 macrophage polarization, and cell surface expression of CD206, CD14, CD16, and CD86, were unaltered. A transwell co-culture system showed that only in mTHP-1 co-cultured with L02 in the presence of exogenous core protein, were higher levels of phosphorylated STAT3 and CD206 seen.

CONCLUSIONS

We showed L02 cells proliferation was accelerated by the culture supernatant of mTHP-1 cells treated with the exogenous HCV core protein. The exogenous core protein mediated the interaction between macrophages and hepatocytes in co-culture, which enhanced the expression of phosphorylated STAT3 and CD206 in macrophages.

Prolactin increases tumor necrosis factor alpha expression in peripheral CD14 monocytes of patients with rheumatoid arthritis

Tumor necrosis factor (TNF)-α is one of the major proinflammatory mediators of rheumatic arthritis (RA); the regulatory factors for TNF-α release is not fully understood. This study aims to investigate the role of prolactin receptor (PRLR) activation in regulating the expression and release of TNF-α from CD14(+) monocytes. The results showed that the expression of PRLR was detectable in CD14(+) monocytes of healthy subjects, which was markedly increased in RA patients. Exposure to PRL in the culture increased the expression and release of TNF-α from CD14(+) monocytes, which was abolished by the PRLR gene silencing or blocking the mitogen activated protein (MAPK) pathway. We conclude that exposure to PRL increases TNF-α release from CD14(+) monocytes of RA patients, which can be abolished by PRLR gene silencing or treating with MAPK inhibitor.

Exploring the importance of translational regulation in the inflammatory responses by a genome-wide approach

It is widely recognized that exercise has an important role in inflammation regulation. To understand inflammatory mechanisms, extensive studies on the transcriptome and proteome have been conducted. However, interpreting these results is difficult, partly due to technical difficulties that impose some restriction on the accuracy and comprehensiveness of measurements. Here we first mention some limitations of studies involving large scale proteomics and high-throughput transcriptomics and further introduce a newly developed genome-wide translational analysis which may overcome some of the limitations and discover novel cellular dynamics. We then show preliminary results obtained by conducting a genome-wide translational analysis of the early inflammatory response of macrophages in response to lipopolysaccharide (LPS), and discuss the potential to identify novel factors by employing a genome-wide translational analysis.

RACK1 promotes the proliferation of THP1 acute myeloid leukemia cells

The receptor for activated C kinase 1 (RACK1), an adaptor protein implicated in the regulation of multiple signaling pathways, has been reported to contribute to the survival of leukemic progenitor cells by enhancing the activity of glycogen synthase kinase 3β (GSK3β). However, it remains unknown whether RACK1 also contributes to the oncogenic growth of acute myeloid leukemia (AML) cells. Here, we report that transient or stable silencing of endogenous RACK1 expression by RACK1 short hairpin RNAs (shRNAs) led to impaired proliferation of THP1 AML cells without inducing terminal differentiation. Further exploration revealed that RACK1 loss-of-function resulted in reduced GSK3β activity. GSK3β shRNA treatment showed similar effects to RACK1 loss-of-function. Our data collectively suggest that RACK1 contributes to THP1 cell proliferation through, at least partially, enhancing GSK3β activity. Thus, targeting RACK1 may have some important therapeutic implications in the treatment of AML.

High dickkopf-1 levels in sera and leukocytes from children with 21-hydroxylase deficiency on chronic glucocorticoid treatment

Children with 21-hydroxylase deficiency (21-OHD) need chronic glucocorticoid (cGC) therapy to replace congenital deficit of cortisol synthesis, and this therapy is the most frequent and severe form of drug-induced osteoporosis. In this study, we enrolled 18 patients (9 females) and 18 sex- and age-matched controls. We found in 21-OHD patients high serum and leukocyte levels of dickkopf-1 (DKK1), a secreted antagonist of the Wnt/β-catenin signaling pathway known to be a key regulator of bone mass. In particular, we demonstrated by flow cytometry, confocal microscopy, and real-time PCR that monocytes, T lymphocytes, and neutrophils from patients expressed high levels of DKK1, which may be related to the cGC therapy. In fact, we showed that dexamethasone treatment markedly induced the expression of DKK1 in a dose- and time-dependent manner in leukocytes. The serum from patients containing elevated levels of DKK1 can directly inhibit in vitro osteoblast differentiation and receptor activator of NF-κB ligand (RANKL) expression. We also found a correlation between both DKK1 and RANKL or COOH-terminal telopeptides of type I collagen (CTX) serum levels in 21-OHD patients on cGC treatment. Our data indicated that DKK1, produced by leukocytes, may contribute to the alteration of bone remodeling in 21-OHD patients on cGC treatment.

No reduction in circulating preosteoclasts 18 months after treatment with zoledronate: analysis from a randomized placebo controlled trial

The conventional model that bisphosphonates bind to the bone surface and inhibit mature osteoclasts does not convincingly explain the prolonged duration of action of zoledronate. We hypothesized that zoledronate on the bone surface adjacent to marrow cells impairs osteoclastogenesis, contributing to sustained inhibition of resorption. In this case, numbers of circulating preosteoclasts may be reduced after zoledronate treatment. This study assessed this possibility in subjects from a clinical trial. Twenty-two osteopenic women participating in a randomized, controlled trial comparing zoledronate 5 mg with placebo were recruited, 18 months after administration of study drug. Peripheral blood mononuclear cells were analyzed for the presence of osteoclast precursors using flow cytometry for preosteoclast markers and the ability to form osteoclast-like cells in culture with RANKL and M-CSF. There was no difference in the percentage of CD14(+)/CD11b(+) cells in peripheral blood between the two groups. The numbers of TRAP(+) multinucleated cells in cultures in the absence of RANKL and M-CSF were very low in both groups, but a significantly higher number of these cells was observed in the zoledronate group compared with the placebo group (p = 0.01). The number of TRAP(+) multinucleated cells and resorption pits following culture with RANKL and M-CSF did not differ between the two groups. Serum P1NP was reduced 53 % at 18 months in the zoledronate group but unchanged in the placebo group. These results do not support the hypothesis that the inhibitory action of zoledronate contributes to its prolonged action on preosteoclasts within bone marrow.

RIN3 is a negative regulator of mast cell responses to SCF

Stimulation of the receptor tyrosine kinase KIT by Stem Cell Factor (SCF) triggers activation of RAS and its downstream effectors. Proper KIT activation is essential for the maturation, survival and proliferation of mast cells. In addition, SCF activation of KIT is critical for recruiting mast cells to sites of infection or injury, where they release a mix of pro-inflammatory substances. RIN3, a RAS effector and RAB5-directed guanine nucleotide exchange factor (GEF), is highly expressed and enriched in human mast cells. SCF treatment of mast cells increased the amount of GTP-bound RAB5, and the degree of RAB5 activation correlated with the expression level of RIN3. At the same time, SCF caused the dissociation of a pre-formed complex of RIN3 with BIN2, a membrane bending protein implicated in endocytosis. Silencing of RIN3 increased the rate of SCF-induced KIT internalization, while persistent RIN3 over-expression led to KIT down regulation. These observations strongly support a role for RIN3 in coordinating the early steps of KIT endocytosis. Importantly, RIN3 also functioned as an inhibitor of mast cell migration toward SCF. Finally, we demonstrate that elevated RIN3 levels sensitize mastocytosis cells to treatment with a KIT tyrosine kinase inhibitor, suggesting the value of a two-pronged inhibitor approach for this difficult to treat malignancy. These findings directly connect KIT activation with a mast cell-specific RAS effector that regulates the cellular response to SCF and provide new insight for the development of more effective mastocytosis treatments.

High-fat diet induces periodontitis in mice through lipopolysaccharides (LPS) receptor signaling: protective action of estrogens

Background

A fat-enriched diet favors the development of gram negative bacteria in the intestine which is linked to the occurrence of type 2 diabetes (T2D). Interestingly, some pathogenic gram negative bacteria are commonly associated with the development of periodontitis which, like T2D, is characterized by a chronic low-grade inflammation. Moreover, estrogens have been shown to regulate glucose homeostasis via an LPS receptor dependent immune-modulation. In this study, we evaluated whether diet-induced metabolic disease would favor the development of periodontitis in mice. In addition, the regulatory role of estrogens in this process was assessed.

Methods

Four-week-old C57BL6/J WT and CD14 (part of the TLR-4 machinery for LPS-recognition) knock-out female mice were ovariectomised and subcutaneously implanted with pellets releasing either placebo or 17β-estradiol (E2). Mice were then fed with either a normal chow or a high-fat diet for four weeks. The development of diabetes was monitored by an intraperitoneal glucose-tolerance test and plasma insulin concentration while periodontitis was assessed by identification of pathogens, quantification of periodontal soft tissue inflammation and alveolar bone loss.

Results

The fat-enriched diet increased the prevalence of periodontal pathogenic microbiota like Fusobacterium nucleatum and Prevotella intermedia, gingival inflammation and alveolar bone loss. E2 treatment prevented this effect and CD14 knock-out mice resisted high-fat diet-induced periodontal defects.

Conclusions/Significance

Our data show that mice fed with a diabetogenic diet developed defects and microflora of tooth supporting-tissues typically associated with periodontitis. Moreover, our results suggest a causal link between the activation of the LPS pathway on innate immunity by periodontal microbiota and HFD-induced periodontitis, a pathophysiological mechanism that could be targeted by estrogens.

Neuroimmunological blood brain barrier opening in experimental cerebral malaria

Plasmodium falciparum malaria is responsible for nearly one million annual deaths worldwide. Because of the difficulty in monitoring the pathogenesis of cerebral malaria in humans, we conducted a study in various mouse models to better understand disease progression in experimental cerebral malaria (ECM). We compared the effect on the integrity of the blood brain barrier (BBB) and the histopathology of the brain of P. berghei ANKA, a known ECM model, P. berghei NK65, generally thought not to induce ECM, P. yoelii 17XL, originally reported to induce human cerebral malaria-like histopathology, and P. yoelii YM. As expected, P. berghei ANKA infection caused neurological signs, cerebral hemorrhages, and BBB dysfunction in CBA/CaJ and Swiss Webster mice, while Balb/c and A/J mice were resistant. Surprisingly, PbNK induced ECM in CBA/CaJ mice, while all other mice were resistant. P. yoelii 17XL and P. yoelii YM caused lethal hyperparasitemia in all mouse strains; histopathological alterations, BBB dysfunction, or neurological signs were not observed. Intravital imaging revealed that infected erythrocytes containing mature parasites passed slowly through capillaries making intimate contact with the endothelium, but did not arrest. Except for relatively rare microhemorrhages, mice with ECM presented no obvious histopathological alterations that would explain the widespread disruption of the BBB. Intravital imaging did reveal, however, that postcapillary venules, but not capillaries or arterioles, from mice with ECM, but not hyperparasitemia, exhibit platelet marginalization, extravascular fibrin deposition, CD14 expression, and extensive vascular leakage. Blockage of LFA-1 mediated cellular interactions prevented leukocyte adhesion, vascular leakage, neurological signs, and death from ECM. The endothelial barrier-stabilizing mediators imatinib and FTY720 inhibited vascular leakage and neurological signs and prolonged survival to ECM. Thus, it appears that neurological signs and coma in ECM are due to regulated opening of paracellular-junctional and transcellular-vesicular fluid transport pathways at the neuroimmunological BBB.

Plasmodium falciparum, the deadliest of all human malaria parasites, can cause cerebral malaria, a severe and frequently fatal complication of this devastating disease. Young children are predominantly at risk and may progress rapidly from the first signs of neurological involvement to coma and death. Here we used a murine model for high-resolution in vivo imaging to demonstrate that cerebral malaria, but not high parasitemia and severe anemia, is associated with extensive leakage of fluid from cerebral blood vessels into the brain tissue. This vascular leakage occurs downstream from the capillary bed, at the neuroimmunological blood brain barrier, a site recently recognized as the immune cell entry point into the brain during neuroinflammation. Vascular leakage is closely associated with the appearance of neurological signs suggesting that the ultimate cause of brain edema, coma and death in cerebral malaria is a widespread opening of the neuroimmunological blood brain barrier. Indeed, vascular leakage, neurological signs, and death from ECM can be prevented with endothelial barrier-stabilizing drugs. Based on the unique role of this anatomical feature in neuroinflammation, our findings are expected to have implications for other infectious diseases and autoimmune disorders of the central nervous system.

Molecular inflammation and adipose tissue matrix remodeling precede physiological adaptations to pregnancy

Changes in adipose tissue metabolism are central to adaptation of whole body energy homeostasis to pregnancy. To gain insight into the molecular mechanisms supporting tissue remodeling, we have characterized the longitudinal changes of the adipose transcriptome in human pregnancy. Healthy nonobese women recruited pregravid were followed in early (8-12 wk) and in late (36-38 wk) pregnancy. Adipose tissue biopsies were obtained in the fasting state from the gluteal depot. The adipose transcriptome was examined via whole genome DNA microarray. Expression of immune-related genes and extracellular matrix components was measured using real-time RT-PCR. Adipose mass, adipocyte size, and cell number increased in late pregnancy compared with pregravid measurements (P < 0.001) but remained unchanged in early pregnancy. The adipose transcriptome evolved during pregnancy with 10-15% of genes being differently expressed compared with pregravid. Functional gene cluster analysis revealed that the early molecular changes affected immune responses, angiogenesis, matrix remodeling, and lipid biosynthesis. Increased expression of macrophage markers (CD68, CD14, and the mannose-6 phosphate receptor) emphasized the recruitment of the immune network in both early and late pregnancy. The TLR4/NF-κB signaling pathway was enhanced specifically in relation to inflammatory adipokines and chemokines genes. We conclude that early recruitment of metabolic and immune molecular networks precedes the appearance of pregnancy-related physiological changes in adipose tissue. This biphasic pattern suggests that physiological inflammation is an early step preceding the development of insulin resistance, which peaks in late pregnancy.

Sex and estradiol influence glial pro-inflammatory responses to lipopolysaccharide in rats

There is a greater prevalence of neuroinflammatory diseases in females than males. Microglia, the major immunocompetent cells of the central nervous system, play a key role in neuroinflammation. We aimed to determine if inherent differences in toll-like receptor 4 mediated pro-inflammatory response in glia could possibly contribute to the skewed female prevalence of neuroinflammatory disorders. In addition, in order to identify if estradiol (E2), the major female sex steroid contributes to a heightened pro-inflammatory response, estradiol was added both in vivo and in vitro. Microglia and astrocytes were isolated from neonatal pups and stimulated with lipopolysaccharide (LPS) in the presence and absence of E2. Hippocampal microglia were isolated from adult male and female rats and stimulated ex vivo with LPS. Male neonatal microglia and astrocytes produced greater IL-1β mRNA than females. However, when co-incubated with varying doses of estradiol (E2), the E2 produced anti-inflammatory effects in the male microglia but a pro-inflammatory effect in female microglia. LPS-induced IL-1β mRNA was attenuated by E2 in female but not male adult hippocampal microglia. However, females supplemented with E2 in vivo produced a potentiated IL-1β mRNA response. TLR4 mRNA was decreased by LPS in both microglia and astrocytes but was not affected by sex or E2. CD14 mRNA was increased by LPS and may be elevated more in females than males in microglia but not astrocytes. Therefore, sexual dimorphic differences do occur in both neonatal and adult microglia though maturity of the microglia at the time of isolation influences the pro-inflammatory response.

Short-term erythropoietin treatment does not substantially modulate monocyte transcriptomes of patients with combined heart and renal failure

BACKGROUND

Combined heart and renal failure is associated with high cardiovascular morbidity and mortality. Anti-oxidant and anti-inflammatory, non-hematopoietic effects of erythropoietin (EPO) treatment have been proposed. Monocytes may act as biosensors of the systemic environment. We hypothesized that monocyte transcriptomes of patients with cardiorenal syndrome (CRS) reflect the pathophysiology of the CRS and respond to short-term EPO treatment at a recommended dose for treatment of renal anemia.

METHODS

Patients with CRS and anemia (n = 18) included in the EPOCARES trial were matched to healthy controls (n = 12). Patients were randomized to receive 50 IU/kg/week EPO or not. RNA from CD14(+)-monocytes was subjected to genome wide expression analysis (Illumina) at baseline and 18 days (3 EPO injections) after enrolment. Transcriptomes from patients were compared to healthy controls and effect of EPO treatment was evaluated within patients.

RESULTS

In CRS patients, expression of 471 genes, including inflammation and oxidative stress related genes was different from healthy controls. Cluster analysis did not separate patients from healthy controls. The 6 patients with the highest hsCRP levels had more differentially expressed genes than the 6 patients with the lowest hsCRP levels. Analysis of the variation in log(2) ratios of all individual 18 patients indicated that 4 of the 18 patients were different from the controls, whereas the other 14 were quite similar. After short-term EPO treatment, every patient clustered to his or her own baseline transcriptome. Two week EPO administration only marginally affected expression profiles on average, however, individual gene responses were variable.

CONCLUSIONS

In stable, treated CRS patients with mild anemia, monocyte transcriptomes were modestly altered, and indicated imprints of inflammation and oxidative stress. EPO treatment with a fixed dose has hematopoietic effects, had no appreciable beneficial actions on monocyte transcription profiles, however, could also not be associated with undesirable transcriptional responses.

Relationship between microbial translocation and endothelial function in HIV infected patients

BACKGROUND

Circulating levels of microbial products are increased in HIV infection, and provoke endothelial dysfunction in other disease settings.

METHODOLOGY/PRINCIPAL FINDINGS

We examined data from a cross-sectional single site study at Indiana University (Indiana, N = 85) and a 24- week multicenter prospective study of antiretroviral therapy (ART) initiation (ACTG 5152s, N = 75). Brachial artery flow-mediated dilation (FMD) was measured by ultrasound. Plasma lipopolysaccharide (LPS) and soluble CD14 (sCD14) levels were measured from stored specimens and correlated with FMD values using Pearson correlations. The Indiana subjects were 63% male with a mean age of 39 years and a median CD4 count of 406 cells/mm(3) (388 not on ART, 464 on ART). The 5152s subjects were 92% were male with a mean age of 35 years and a median CD4 count of 251 cells/mm(3) at entry which increased to 396 cells/mm(3) on ART. When analyzing the two cohorts individually or in combination neither sCD14 nor LPS correlated significantly with FMD. In a pre-specified subgroup analysis of the Indiana subjects receiving ART (N = 46, mean ART duration 40 months) LPS was inversely correlated with FMD (r = -0.33, p = 0.02), but not sCD14 (r = -0.01, p = 0.9). Multivariate analysis confirmed LPS as an independent predictor of FMD in this subgroup (p = 0.02).

CONCLUSIONS/SIGNIFICANCE

In HIV-infected individuals on prolonged ART, higher LPS levels are associated with worse endothelial function but not in untreated subjects or at 24 weeks after ART initiation. Persistent microbial translocation may contribute to arterial dysfunction and the increased cardiovascular disease risk observed in individuals on long-term ART.

Monocytes regulate the mechanism of T-cell death by inducing Fas-mediated apoptosis during bacterial infection

Monocytes and T-cells are critical to the host response to acute bacterial infection but monocytes are primarily viewed as amplifying the inflammatory signal. The mechanisms of cell death regulating T-cell numbers at sites of infection are incompletely characterized. T-cell death in cultures of peripheral blood mononuclear cells (PBMC) showed 'classic' features of apoptosis following exposure to pneumococci. Conversely, purified CD3(+) T-cells cultured with pneumococci demonstrated necrosis with membrane permeabilization. The death of purified CD3(+) T-cells was not inhibited by necrostatin, but required the bacterial toxin pneumolysin. Apoptosis of CD3(+) T-cells in PBMC cultures required 'classical' CD14(+) monocytes, which enhanced T-cell activation. CD3(+) T-cell death was enhanced in HIV-seropositive individuals. Monocyte-mediated CD3(+) T-cell apoptotic death was Fas-dependent both in vitro and in vivo. In the early stages of the T-cell dependent host response to pneumococci reduced Fas ligand mediated T-cell apoptosis was associated with decreased bacterial clearance in the lung and increased bacteremia. In summary monocytes converted pathogen-associated necrosis into Fas-dependent apoptosis and regulated levels of activated T-cells at sites of acute bacterial infection. These changes were associated with enhanced bacterial clearance in the lung and reduced levels of invasive pneumococcal disease.

HemaMax™, a recombinant human interleukin-12, is a potent mitigator of acute radiation injury in mice and non-human primates

HemaMax, a recombinant human interleukin-12 (IL-12), is under development to address an unmet medical need for effective treatments against acute radiation syndrome due to radiological terrorism or accident when administered at least 24 hours after radiation exposure. This study investigated pharmacokinetics, pharmacodynamics, and efficacy of m-HemaMax (recombinant murine IL-12), and HemaMax to increase survival after total body irradiation (TBI) in mice and rhesus monkeys, respectively, with no supportive care. In mice, m-HemaMax at an optimal 20 ng/mouse dose significantly increased percent survival and survival time when administered 24 hours after TBI between 8–9 Gy (p<0.05 Pearson's chi-square test). This survival benefit was accompanied by increases in plasma interferon-γ (IFN-γ) and erythropoietin levels, recovery of femoral bone hematopoiesis characterized with the presence of IL-12 receptor β2 subunit–expressing myeloid progenitors, megakaryocytes, and osteoblasts. Mitigation of jejunal radiation damage was also examined. At allometrically equivalent doses, HemaMax showed similar pharmacokinetics in rhesus monkeys compared to m-HemaMax in mice, but more robustly increased plasma IFN-γ levels. HemaMax also increased plasma erythropoietin, IL-15, IL-18, and neopterin levels. At non-human primate doses pharmacologically equivalent to murine doses, HemaMax (100 ng/Kg and 250 ng/Kg) administered at 24 hours after TBI (6.7 Gy/LD_50/30) significantly increased percent survival of HemaMax groups compared to vehicle (p<0.05 Pearson's chi-square test). This survival benefit was accompanied by a significantly higher leukocyte (neutrophils and lymphocytes), thrombocyte, and reticulocyte counts during nadir (days 12–14) and significantly less weight loss at day 12 compared to vehicle. These findings indicate successful interspecies dose conversion and provide proof of concept that HemaMax increases survival in irradiated rhesus monkeys by promoting hematopoiesis and recovery of immune functions and possibly gastrointestinal functions, likely through a network of interactions involving dendritic cells, osteoblasts, and soluble factors such as IL-12, IFN-γ, and cytoprotectant erythropoietin.

Macrophage sub-populations and the lipoxin A4 receptor implicate active inflammation during equine tendon repair

Macrophages (Mϕ) orchestrate inflammatory and reparatory processes in injured connective tissues but their role during different phases of tendon healing is not known. We investigated the contribution of different Mϕ subsets in an equine model of naturally occurring tendon injury. Post mortem tissues were harvested from normal (uninjured), sub-acute (3–6 weeks post injury) and chronically injured (>3 months post injury) superficial digital flexor tendons. To determine if inflammation was present in injured tendons, Mϕ sub-populations were quantified based on surface antigen expression of CD172a (pan Mϕ), CD14^highCD206^low (pro-inflammatory M1Mϕ), and CD206^high (anti-inflammatory M2Mϕ) to assess potential polarised phenotypes. In addition, the Lipoxin A₄ receptor (FPR2/ALX) was used as marker for resolving inflammation. Normal tendons were negative for both Mϕ and FPR2/ALX. In contrast, M1Mϕ predominated in sub-acute injury, whereas a potential phenotype-switch to M2Mϕ polarity was seen in chronic injury. Furthermore, FPR2/ALX expression by tenocytes was significantly upregulated in sub-acute but not chronic injury. Expression of the FPR2/ALX ligand Annexin A1 was also significantly increased in sub-acute and chronic injuries in contrast to low level expression in normal tendons. The combination of reduced FPR2/ALX expression and persistence of the M2Mϕ phenotype in chronic injury suggests a potential mechanism for incomplete resolution of inflammation after tendon injury. To investigate the effect of pro-inflammatory mediators on lipoxin A₄ (LXA₄) production and FPR2/ALX expression in vitro, normal tendon explants were stimulated with interleukin-1 beta and prostaglandin E₂. Stimulation with either mediator induced LXA₄ release and maximal upregulation of FPR2/ALX expression after 72 hours. Taken together, our data suggests that although tenocytes are capable of mounting a protective mechanism to counteract inflammatory stimuli, this appears to be of insufficient duration and magnitude in natural tendon injury, which may potentiate chronic inflammation and fibrotic repair, as indicated by the presence of M2Mϕ.

A resveratrol and polyphenol preparation suppresses oxidative and inflammatory stress response to a high-fat, high-carbohydrate meal

BACKGROUND

High-fat, high-carbohydrate (HFHC) meals are known to induce oxidative and inflammatory stress, an increase in plasma endotoxin concentrations, and an increase in the expression of suppressor of cytokine signaling-3 (SOCS-3).

HYPOTHESIS

The intake of a nutritional supplement containing resveratrol and muscadine grape polyphenols reduces HFHC meal-induced oxidative and inflammatory stress and stimulates the activity of the antioxidant transcription factor, NF-E2-related factor-2 (Nrf-2), and its downstream targets.

METHODS

Ten normal, healthy subjects were given a 930-kcal HFHC meal either with placebo or with the supplement. Indices of oxidative stress, inflammation, Nrf-2 binding activity, the concentrations of endotoxin (lipopolysaccharide) and lipoprotein binding protein (LBP), and the expression of toll-like receptor 4 (TLR-4), CD14, IL-1β, TNFα, SOCS-3, Keap-1, NAD(P)H:quinone oxidoreductase-1 (NQO-1), and GST-P1 were measured.

RESULTS

The intake of the supplement suppressed the meal-induced elevations of plasma endotoxin and LBP concentrations, the expression of p47(phox), TLR-4, CD14, SOCS-3, IL-1β, and Keap-1, while enhancing Nrf-2 binding activity and the expression of NQO-1 and GST-P1 genes.

CONCLUSION

A supplement containing resveratrol and muscadine polyphenols suppresses the increase in oxidative stress, lipopolysaccharide and LBP concentrations, and expression of TLR-4, CD14, IL-1β and SOCS-3 in mononuclear cells after an HFHC meal. It also stimulates specific Nrf-2 activity and induces the expression of the related antioxidant genes, NQO-1 and GST-P1. These results demonstrate the acute antioxidant and antiinflammatory effects of resveratrol and polyphenolic compounds in humans in the postprandial state.

Immunophenotypic characterization of human monocyte subsets: possible implications for cardiovascular disease pathophysiology

OBJECTIVES

Monocytes include several subsets with different and sometimes divergent roles in immunity, atherogenesis and reparative processes.

OBJECTIVES

We aimed to perform detailed immunophenotypic and functional characterization of human monocyte subsets.

PATIENTS/METHODS

Analysis of surface markers of blood and bone marrow monocyte subsets and functional characterization of blood monocyte subsets in healthy volunteers was performed using flow cytometry.

RESULTS

In the present study, we show the presence of three subsets which could be unequivocally distinguished by surface expression of CD14, CD16 and CCR2 as CD14(+)CD16(-)CCR2(+) (Mon1), CD14(+)CD16(+)CCR2(+) (Mon2) and CD14(low)CD16(+)CCR2(-) (Mon3) subsets. In comparison with the classic Mon1, the Mon2 subset had the highest expression of Tie2, CXCR4, CD163, CD115, receptors to inter-cellular adhesion molecule-1 (ICAM-1), vascular endothelial growth factor (VEGF), and the highest surface levels of apolipoprotein B and ferritin. In contrast, Mon3 had maximal expression of VCAM-1 receptors and CD204. The Mon2 and Mon3 subsets had significantly lower activity of the NFκB pathway than Mon1. Mon1 and Mon2 had similar phagocytic activity, which was significantly higher compared with Mon3. All three subsets were present in bone marrow, although the relative proportion of Mon2 in bone marrow was about 2.5-fold higher compared with that seen in blood. Significant differences in cytokine production in response to endotoxin stimulation were observed between the three monocyte subsets.

CONCLUSION

Given their immunophenotypic similarity, the newly characterized Mon2 population may represent the previously reported pluripotent progenitor/pro-angiogenic monocytes.

Severe gunshot injuries in a porcine model: impact on central markers of innate immunity

BACKGROUND

the mechanisms behind lipopolysaccharide (LPS) tolerance remain obscure. LPS signals through Toll-like receptor 4 (TLR4) and severe trauma/haemorrhage may influence binding and signalling through this receptor, e.g. by changing membrane expression or by releasing endogenous ligands like High Mobility Group Box 1 (HMGB1). The aim of this study was to examine these relations further in a porcine model with standardized trauma.

METHODS

nine anaesthetized pigs sustained one gunshot through the femur and one pistol shot through the upper abdomen. Blood was sampled before and 90 min after shooting. The samples were stimulated for 4 h with LPS 10 ng/ml or an equivalent amount of normal saline. The leucocyte response was evaluated by measuring the tumour necrosis factor-α (TNF-α) and CXC ligand 8 (CXCL8) in the supernatant. Flow cytometry was used to measure the surface expression of TLR4 on CD14+ monocytes. HMGB1 concentrations were measured in the plasma.

RESULTS

trauma and treatment caused a significant decline in the LPS-stimulated concentrations of TNF-α [4.53 ± 0.24 pg/ml (ln) at 0 min, 3.54 ± 0.35 pg/ml (ln) at 90 min, P=0.026], but did not modify the release of CXCL8. Monocyte TLR4 expression was unchanged. Plasma HMGB1 increased significantly [<0.92 vs. 3.02 ± 0.19 ng/ml (ln), P<0.001]. The concentrations of TNF-α and CXCL8 did not correlate with TLR4 expression or HMGB1 concentrations.

CONCLUSION

the results suggest that trauma-induced LPS tolerance is not primarily regulated by TLR4 expression on circulating CD14+ monocytes or by the release of HMGB1 from damaged tissues.

A subset of human pancreatic beta cells express functional CD14 receptors: a signaling pathway for beta cell-related glycolipids, sulfatide and β-galactosylceramide

BACKGROUND

T1DM is a T-cell-mediated autoimmune disease targeting insulin-producing beta-cells. Multiple factors may contribute to the development of T1DM. Among these, the metabolic state of beta-cells and pro-inflammatory cytokines, produced by infiltrating immune cells, have been implicated in the precipitation of T1DM.

METHODS AND RESULTS

In this study, confocal immunofluorescence microscopy of human pancreata revealed a distinct subset of beta-cells expressing the innate LPS co-receptor CD14. Human islets expressed fully functional CD14 as LPS stimulation led to a dose-dependent secretion of tumour necrosis factor (TNFα), interleukin (IL)-1β and IL-8, which were substantially inhibited by a blocking anti-CD14 mAb. In addition, LPS stimulation impaired the glucose-mediated insulin secretion in rat islets. β-GalCer and sulfatide, glycolipids that are related to insulin processing and secretion, are possibly interacting with the CD14 receptor complex. β-GalCer had an LPS-like, serum- and CD14-dependent effect on the induction of pro-inflammatory cytokines in a human monocyte cell line. In contrast, the LPS-mediated cytokine production was inhibited by sulfatide. Human islets also responded to β-GalCer (10 µg/mL) by secreting TNFα, IL-1β and IL-8, whereas sulfatide partly inhibited the effect of LPS.

CONCLUSIONS

A subset of human beta-cells expresses functional CD14 receptor and thus is able to recognize both exogenous bacterial (LPS) as well as endogenous ligands (e.g. glycolipids of beta-cell origin). The CD14 expression on a subset of human beta-cells may play a role in the innate surveillance of the endocrine environment but may also contribute to innate immune mechanisms in the early stages of beta-cell aggression.

TLR4 and CD14 receptors expressed in rat pineal gland trigger NFKB pathway

Nuclear factor-kappa B (NFKB), a pivotal player in inflammatory responses, is constitutively expressed in the pineal gland. Corticosterone inhibits pineal NFKB leading to an enhancement of melatonin production, while tumor necrosis factor (TNF) leads to inhibition of Aa-nat transcription and the production of N-acetylserotonin in cultured glands. The reduction in nocturnal melatonin surge favors the mounting of the inflammatory response. Despite these data, there is no clear evidence of the ability of the pineal gland to recognize molecules that signal infection. This study investigated whether the rat pineal gland expresses receptors for lipopolysaccharide (LPS), the endotoxin from the membranes of Gram-negative bacteria, and to establish the mechanism of action of LPS. Here, we show that pineal glands possess both CD14 and toll-like receptor 4 (TLR4), membrane proteins that bind LPS and trigger the NFKB pathway. LPS induced the nuclear translocation of p50/p50 and p50/RELA dimers and the synthesis of TNF. The maximal expression of TNF in cultured glands coincides with an increase in the expression of TNF receptor 1 (TNFR1) in isolated pinealocytes. In addition, LPS inhibited the synthesis of N-acetylserotonin and melatonin. Therefore, the pineal gland transduces Gram-negative endotoxin stimulation by producing TNF and inhibiting melatonin synthesis. Here, we provide evidence to reinforce the idea of an immune-pineal axis, showing that the pineal gland is a constitutive player in the innate immune response.

CD14 polymorphisms and serum CD14 levels through childhood: a role for gene methylation?

BACKGROUND

CD14 is a pattern-recognition receptor for environmental LPS, and engagement of the CD14-LPS complex activates innate host defense mechanisms. Single nucleotide polymorphisms (SNPs) in the CD14 gene have been associated with soluble CD14 (sCD14) levels, but inconsistencies between studies suggest the presence of regulatory mechanisms hitherto not well understood.

OBJECTIVE

We sought to investigate possible associations between CD14 SNPs and sCD14 levels at different time points in childhood (at birth [cord blood] and 2 and 10 years) and to explore whether these associations were related to CD14 gene methylation.

METHODS

Four SNPs, rs2569191 (-1145GA), rs5744455 (-550CT or -651CT), rs2569190 (-159CT or -260CT), and rs4914 in CD14 were genotyped in 762 children from the Environmental and Childhood Asthma study. Genotype frequencies were analyzed for association with sCD14 levels in 660 babies, 346 children at age 2 years, and 360 children at age 10 years. In a subgroup of 157 children with DNA available at both 2 and 10 years of age, CD14 methylation patterns were determined and analyzed against detected CD14 gene-sCD14 associations.

RESULTS

rs2569191, rs5744455, and rs2569190 were associated with sCD14 levels at birth and 2 years, but only rs5744455 was associated with sCD14 levels at 10 years. CD14 methylation increased significantly from age 2 to 10 years, and the level of methylation was inversely correlated with sCD14 levels at 10 years.

CONCLUSION

The reduced effect of CD14 polymorphisms on sCD14 levels from early to late childhood paralleled a small but significant increase in CD14 methylation during the same period.

Distinct types of fibrocyte can differentiate from mononuclear cells in the presence and absence of serum

Background

Fibrocytes are bone-marrow derived cells, expressing both haematopoietic and stromal cell markers, which contribute to tissue repair as well as pathological fibrosis. The differentiation of fibrocytes remains poorly characterised and this has limited understanding of their biology and function. In particular two methods are used to generate fibrocytes in vitro that differ fundamentally by the presence or absence of serum.

Methodology/Principal Findings

We show here that fibrocytes grown in the absence of serum (SF) differentiate more efficiently from peripheral blood mononuclear cells than CD14⁺ monocytes, and respond to serum by losing their spindle-shaped fibrocyte morphology. Although fibrocytes generated in the presence of serum (SC) express the same range of markers, they differentiate more efficiently from CD14⁺ monocytes and do not change their morphology in response to serum. Transcriptional analysis revealed that both types of fibrocyte are distinct from each other, fibroblasts and additional monocyte-derived progeny. The gene pathways that differ significantly between SF and SC fibrocytes include those involved in cell migration, immune responses and response to wounding.

Conclusions/Significance

These data show that SF and SC fibrocytes are distinct but related cell types, and suggest that they will play different roles during tissue repair and fibrosis where changes in serum proteins may occur.

Propofol has anti-inflammatory effects on alveolar type II epithelial cells

BACKGROUND

We investigated whether lipopolysaccharide (LPS) induced inflammation in alveolar epithelial type II (ATII) cells is through cluster of differentiation 14 (CD14) and Toll-like receptor 4 (TLR4) and the effect of different dosages of propofol on the inflammation in primary cultured rat ATII cells.

METHODS

Cultured ATII cells were randomly assigned to one of the following five groups: Group C: untreated group (control) cultured in the absence of propofol and LPS; Group LPS: treated with 1 microg/ml LPS; Group P1: treated with 1 microg/ml LPS and 25 microM propofol; Group P2: treated with 1 microg/ml LPS and 50 microM propofol; Group P3: treated with 1 microg/ml LPS and 100 microM propofol. ATII cells in all groups were cultured at 37 degrees C for 3 h. CD14 and TLR4 mRNA was detected using real-time polymerase chain reaction. Western blot was used to detect CD14 and TLR4 protein expression. CD14 and TLR4 expression on the ATII cells was imaged using immunofluorescence. Tumor necrosis factor-alpha (TNF-alpha) production was determined using an ELISA kit.

RESULTS

LPS stimulation resulted in an increased CD14 and TLR4 expression and increased TNF-alpha production in ATII cells. Propofol, at concentrations > or = 50 microM, significantly (P<0.05) and dose-dependently decreased CD14 and TLR4 mRNA expression and protein expression in ATII cells. This was accompanied by a decrease in TNF-alpha production (P<0.05).

CONCLUSION

These results suggest that propofol, at clinically relevant concentrations, can reduce inflammatory responses in LPS-induced ATII cells injury through downregulation of CD14 and TLR4 expression.

Porcine EPCs downregulate stem cell markers and upregulate endothelial maturation markers during in vitro cultivation

In recent years, interest in endothelial progenitor cells (EPCs) in the field of tissue engineering and regenerative medicine has increased tremendously. However, each clinical stem cell application requires prior validation through animal experiments. This study investigates the isolation and characterization of porcine EPCs from peripheral blood and the change of their cell surface marker expression during in vitro cultivation. RT-PCR demonstrated that the EPCs express stem cell markers CD34 and CD133, which decrease with in vitro cultivation time. Throughout the cultivation process EPCs did not express monocytic (CD14) or haematopoietic marker (CD45). Surprisingly, the CD31 and VE-cadherin expression in EPCs was significantly higher than in endothelial cells (ECs). In contrast, the VEGFR2 and E-selectin expression was significantly lower than in ECs, but increased during the expansion process. This study clarifies the characteristic properties of porcine EPCs during cell culture and may help to improve the impact of EPC-based therapies in porcine animal studies.

Oxidant alterations in CD16 expression are cytoskeletal induced

Oxidative stress during reperfusion of ischemia is associated with a phenotypic change in circulating monocytes from CD14++CD16- to a proinflammatory CD14+CD16+ subpopulation resulting in altered immunity and development of organ failure. However, the mechanism responsible remains unknown. We hypothesize that this phenotypic change, modeled by hydrogen peroxide exposure in vitro, is due to oxidative-induced intracellular calcium flux and distinct cytoskeletal and lipid raft changes. Peripheral blood monocytes obtained from healthy volunteers underwent 100 mM H2O2 exposure for 0 to 24 h. Selected cells were pretreated with 2 microM cytochalasin D, 1 microM lactrunculin A, or 30 microM 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid for 30 min. Cells underwent fluorescence-activated cell sorter for CD14, CD16, and cytokine expression. Cellular and lipid raft CD16 expression was determined by immunoblot and confocal microscopy. H2O2 exposed monocytes underwent a rapid time-dependent increase in the surface expression of CD16 from 12.81% +/- 3.53% to 37.12% +/- 7.61% at 24 h (P = 0.001). Total cellular CD16 was not changed by H2O2, but an increase in lipid raft and decrease in intracellular CD16 expression were seen after H2O2 exposure. This increase in CD16 expression was associated with a 27% increase in intracellular TNF-alpha, an alteration in actin polymerization, and the formation of raft macrodomains. These changes induced by H2O2 were inhibited by inhibition of actin polymerization (cytochalasin D and lactrunculin A) and intracellular calcium flux [1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid]. This study provides the first evidence that phenotypic alterations induced by oxidative stress during reperfusion may occur as a result of changes in cytoskeletal architecture due to calcium flux that result in lipid raft alterations rather than solely from demargination and/or production of bone marrow-derived CD16+ monocytes.

Monocyte scintigraphy in rheumatoid arthritis: the dynamics of monocyte migration in immune-mediated inflammatory disease

BACKGROUND

Macrophages are principal drivers of synovial inflammation in rheumatoid arthritis (RA), a prototype immune-mediated inflammatory disease. Conceivably, synovial macrophages are continuously replaced by circulating monocytes in RA. Animal studies from the 1960s suggested that macrophage replacement by monocytes is a slow process in chronic inflammatory lesions. Translation of these data into the human condition has been hampered by the lack of available techniques to analyze monocyte migration in man.

METHODS/PRINCIPAL FINDINGS

We developed a technique that enabled us to analyze the migration of labelled autologous monocytes in RA patients using single photon emission computer tomography (SPECT). We isolated CD14+ monocytes by CliniMACS in 8 patients and labeled these with technetium-99m (99mTc-HMPAO). Monocytes were re-infused into the same patient. Using SPECT we calculated that a very small but specific fraction of 3.4 x 10(-3) (0.95-5.1 x 10(-3)) % of re-infused monocytes migrated to the inflamed joints, being detectable within one hour after re-infusion.

CONCLUSIONS/SIGNIFICANCE

The results indicate monocytes migrate continuously into the inflamed synovial tissue of RA patients, but at a slow macrophage-replacement rate. This suggests that the rapid decrease in synovial macrophages that occurs after antirheumatic treatment might rather be explained by an alteration in macrophage retention than in monocyte influx and that RA might be particularly sensitive to treatments targeting inflammatory cell retention.

HIV-1 residual viremia correlates with persistent T-cell activation in poor immunological responders to combination antiretroviral therapy

BACKGROUND

The clinical significance and cellular sources of residual human immunodeficiency virus type 1 (HIV-1) production despite suppressive combination antiretroviral therapy (cART) remain unclear and the effect of low-level viremia on T-cell homeostasis is still debated.

METHODOLOGY/PRINCIPAL FINDINGS

We characterized the recently produced residual viruses in the plasma and short-lived blood monocytes of 23 patients with various immunological responses to sustained suppressive cART. We quantified the residual HIV-1 in the plasma below 50 copies/ml, and in the CD14(high) CD16(-) and CD16+ monocyte subsets sorted by flow cytometry, and predicted coreceptor usage by genotyping V3 env sequences. We detected residual viremia in the plasma of 8 of 10 patients with poor CD4+ T-cell reconstitution in response to cART and in only 5 of 13 patients with good CD4+ T-cell reconstitution. CXCR4-using viruses were frequent among the recently produced viruses in the plasma and in the main CD14(high) CD16(-) monocyte subset. Finally, the residual viremia was correlated with persistent CD4+ and CD8+ T-cell activation in patients with poor immune reconstitution.

CONCLUSIONS

Low-level viremia could result from the release of archived viruses from cellular reservoirs and/or from ongoing virus replication in some patients. The compartmentalization of the viruses between the plasma and the blood monocytes suggests at least two origins of residual virus production during effective cART. CXCR4-using viruses might be produced preferentially in patients on cART. Our results also suggest that low-level HIV-1 production in some patients may contribute to persistent immune dysfunction despite cART.

Cholesteatoma growth and proliferation: posttranscriptional regulation by microRNA-21

OBJECTIVES

The goal of this study was to identify novel regulatory mechanisms controlling the growth and proliferation of cholesteatoma. Specifically, the potential role of microRNAs, regulators of protein translation, was studied in cholesteatoma.

STUDY DESIGN

This study represents a molecular biologic investigation characterizing and comparing microRNA and protein expression in cholesteatoma and normal postauricular skin.

METHODS

Cholesteatoma and normal skin were taken from patients at the time of surgery. Tissue was processed for RNA and protein extraction. Real-time reverse-transcriptase-polymerase chain reaction was used to assess levels of human microRNAs, reverse-transcriptase-polymerase chain reaction was used to confirm the presence of upstream regulators, and Western blot analyses were used to assess levels of downstream target proteins.

RESULTS

Among the microRNAs investigated, human microRNA-21 (hsa-miR-21) showed a 4.4-fold higher expression in cholesteatoma as compared with normal skin (p = 0.0011). The downstream targets of hsa-miR-21, PTEN and programmed cell death 4, were found to be greatly reduced in 3 of 4 cholesteatoma samples. Proposed upstream regulators of hsa-miR-21 expression (CD14, interleukin 6R, gp130, and signal transducer and activator of transcription 3) were present in all cholesteatoma tissues.

CONCLUSION

MicroRNAs represent powerful regulators of protein translation, and their dysregulation has been implicated in many neoplastic diseases. This study specifically identified up-regulation of hsa-miR-21 concurrent with down-regulation of potent tumor suppressor proteins PTEN and programmed cell death 4. These proteins control aspects of apoptosis, proliferation, invasion, and migration. The results of this study were used to develop a model for cholesteatoma proliferation through microRNA dysregulation. This model can serve as a template for further study into potential RNA-based therapies for the treatment of cholesteatoma.

High expression of Toll-like receptor 4 on CD14+ monocytes in acute infectious diseases

Toll-like receptor 4 (TLR4) recognizes lipopolysaccharide (LPS) and other exogenous and endogenous molecules, and is thought to contribute to defense mechanisms against infections. Our objective was to elucidate the clinical significance of TLR4 in acute infectious diseases by analyzing its sequential expression on CD14+ monocytes. Peripheral blood samples were obtained from 36 patients with acute infectious diseases on admission and after treatment within certain intervals. The TLR4 expression on CD14+ monocytes was analyzed using flow cytometry and was presented as a mean fluorescence intensity (MFI). TLR4 expression during the acute phase of infection was highly enhanced compared to that of normal subjects (MFI: 22.1 vs 8.5). TLR4 expression was promptly reduced to normal levels in parallel with the disease improvement. In patients who died despite treatment, the enhancement of TLR4 expression during the acute phase was less prominent compared to those who survived (MFI: 14.6 vs 23.5) and its sequential change was also subtle. These results indicate that monocytes respond to acute infections by the induction of TLR4 expression and that a poor response may be associated with a poor prognosis.

[The effect of recombinant panton-valentine leukocidin on the production of cytokines by human alveolar macrophages]

OBJECTIVE

To investigate the effect of recombinant panton-valentine leukocidin (rPVL) on the regulation of human alveolar macrophage CD14 and IL-10 and TNF-alpha.

METHODS

Human alveolar macrophages (AM) were purified and cultured from bronchoalveolar lavage fluid. Each sample was divided into groups according to different concentrations and exposure times of rPVL. Semi-quantitative RT-PCR was used to evaluate the CD14 mRNA levels and Double-antibody-sandwich-ELISA was used to measure the IL-10 and TNF-alpha levels in AM cultures.

RESULTS

CD14 mRNA decreased after rPVL treatment in time-and concentration dependent manners. There were no statistically significant differences in CD14 mRNA among the blank control groups (F = 1.708, P > 0.05). CD14 mRNA in the T6N10 group and the T6N100 group( T = time in hours, N = concentration of rPVL/nmol/L) decreased as compared to the T6N0 group (t = 4.132, 6.818, both P < 0.001), and that in the T24N10 group and the T24N100 group also decreased as compared to the T24N0 group (t = 7.401, 11.415, both P < 0.001), indicating that the expression of CD14 was downregulated by rPVL treatment. There were also statistically significant differences in CD14 mRNA between T6N10 and T24N10 groups, T6N100 and T24N100 groups (t = 4.692, 6.019, both P < 0.001), T6N10 and T6N100 groups, T24N10 and T24N100 groups (t = 2.686, 4.014, P < 0.01 respectively), indicating that the expression of CD14 decreased as the treatment time and the concentration of rPVL increased. The IL-10 concentrations of the T24N10 and T24N100 groups increased as compared to the T24N0 group (t = 4.036, 3.941, both P < 0.01) in time-dependent and concentration-dependent manners with rPVL treatment. The TNF-alpha concentration of the T24N10 group decreased while that of the T24N100 group increased as compared to the T24N0 group (t = 2. 824, 8. 468, both P < 0.01, respectively), indicating that a lower concentration of rPVL inhibited TNF-alpha release while a higher concentration of rPVL induced release of TNF-alpha.

CONCLUSION

The results suggest that rPVL could reduce the expression of CD14 and induce disordered release of anti-inflammatory and proinflammatory cytokines by AMs, which may be one of the important mechanisms underlying the high mortality of infection with PVL-positive Staphylococcus aureus.

Necator americanus infection: a possible cause of altered dendritic cell differentiation and eosinophil profile in chronically infected individuals

BACKGROUND

Hookworms survive for several years (5 to 7 years) in the host lumen, inducing a robust but largely ineffective immune response. Among the most striking aspects of the immune response to hookworm (as with many other helminths) is the ablation of parasite-specific T cell proliferative response (hyporesponsiveness). While the role of the adaptive immune response in human helminth infection has been well investigated, the role of the innate immune responses (e.g., dendritic cells and eosinophils) has received less attention and remains to be clearly elucidated.

METHODOLOGY/PRINCIPAL FINDINGS

We report on the differentiation/maturation of host dendritic cells in vitro and the eosinophil activation/function associated with human hookworm infection. Mature DCs (mDCs) from Necator americanus (Necator)-infected individuals showed an impaired differentiation process compared to the mDCs of non-infected individuals, as evidenced by the differential expression of CD11c and CD14. These same hookworm-infected individuals also presented significantly down-regulated expression of CD86, CD1a, HLA-ABC, and HLA-DR. The lower expression of co-stimulatory and antigen presentation molecules by hookworm-infected-derived mDCs was further evidenced by their reduced ability to induce cell proliferation. We also showed that this alternative DC differentiation is partially induced by excreted-secreted hookworm products. Conversely, eosinophils from the same individuals showed a highly activated status, with an upregulation of major cell surface markers. Antigen-pulsed eosinophils from N. americanus-infected individuals induced significant cell proliferation of autologous PBMCs, when compared to non-infected individuals.

CONCLUSION

Chronic N. americanus infection alters the host's innate immune response, resulting in a possible modulation of the maturation process of DCs, a functional change that may diminish their ability for antigen presentation and thus contribute to the ablation of the parasite-specific T cell proliferative response. Interestingly, a concomitant upregulation of the major cell surface markers of eosinophils was observed in hookworm-infected individuals, indicative of antigen-specific immune responses, especially antigen presentation. We showed that in addition to the postulated role of the eosinophils as effector cells against helminth infection, activated cells may also be recruited to sites of inflammation and contribute to the immune response acting as antigen presenting cells.

Expression of toll-like receptor 2 on peripheral blood monocytes of patients with inflammatory and noninflammatory acne vulgaris

The pathogenesis of acne vulgaris is multifactorial and entails the interplay of hormonal, microbial and immunological events. The bacterium Propionibacterium acnes is involved in the induction of comedogenesis and maintenance of the inflammatory phase of acne. Toll-like Receptor 2 (TLR2) expressed on mononuclear inflammatory cells and possibly on keratinocytes and sebocytes is thought to be of vital importance in mediating P. acnes-induced inflammatory response in acne vulgaris. This work aimed to study the degree of expression of TLR2 on peripheral blood monocytes (PBM) from patients with non-inflammatory and inflammatory acne and to investigate the influence of systemic isotretinoin therapy on TLR2 expression. Sixteen patients with predominantly non-inflammatory acne, 16 patients with predominantly inflammatory acne and 16 age and sex matched healthy subjects were involved in this study. Cell surface expression of CD14 and TLR2 were determined by cell surface staining and flowcytometry. TLR2 expression was analyzed for 12 patients with severe and/or scaring inflammatory acne after oral isotretinoin therapy for two months. The mean fluorescence intensity (MFI) of TLR2 on PBM reported a statistically significant difference between patients with non-inflammatory acne, patients with inflammatory acne and control subjects. MFI of TLR was significantly lower for patients with inflammatory acne after systemic isotretinoin therapy. Data obtained suggest that TLR2 expression on PBM is an important event in acne pathogenesis and targeting this molecule might be a useful therapeutic goal in the future.

Blood COX-2 and PGES gene transcription during the peripartum period of dairy cows with normal puerperium or with uterine infection

In the dairy cow, puerperal uterine intra-luminal concentrations of PGE(2) are related to the establishment and severity of uterine infections. Here we evaluated whether the blood concentrations of PGE(2) and the gene transcription profiles of enzymes involved in its synthesis (cyclooxygenase-2 and prostaglandin E synthase) could be used as markers of predisposition and/or presence of puerperal uterine infections. We also studied the relationship between the endocrine status and the leukocyte profiles around parturition and the transcription patterns of the genes. Finally, we have characterized the in vitro gene transcription and expression response to a challenge of LPS. Gene transcription profiles, quantified by real-time PCR, were similar in normal puerperium and metritis/endometritis cows, indicating that they are not suitable markers of predisposition to/presence of puerperal uterine infections. Transcription decreased from 2 weeks before parturition until parturition, when a minimum was attained, and then increased during the first week postpartum. The lowest gene transcription, at parturition, was coincidental with the highest total leukocytes, polymorphonuclear neutrophils and CD14 positive cell numbers. It is suggested that by this mechanism, a large number of PMN can be recruited into the uterus after parturition, avoiding an excessive acute inflammatory response. The lowest gene transcription was also coincidental with the surge in cortisol concentrations, indicating that this hormone plays a main immunomodulatory role around parturition. Gene transcription was significantly greater after stimulation with LPS than in non-stimulated blood. We suggest that this PGE(2) producing cells might arrive to the uterine lumen, contributing to the local PGE(2) concentrations and mediating the inflammatory response.

Activin A induces Langerhans cell differentiation in vitro and in human skin explants

Langerhans cells (LC) represent a well characterized subset of dendritic cells located in the epidermis of skin and mucosae. In vivo, they originate from resident and blood-borne precursors in the presence of keratinocyte-derived TGFbeta. In vitro, LC can be generated from monocytes in the presence of GM-CSF, IL-4 and TGFbeta. However, the signals that induce LC during an inflammatory reaction are not fully investigated. Here we report that Activin A, a TGFbeta family member induced by pro-inflammatory cytokines and involved in skin morphogenesis and wound healing, induces the differentiation of human monocytes into LC in the absence of TGFbeta. Activin A-induced LC are Langerin+, Birbeck granules+, E-cadherin+, CLA+ and CCR6+ and possess typical APC functions. In human skin explants, intradermal injection of Activin A increased the number of CD1a+ and Langerin+ cells in both the epidermis and dermis by promoting the differentiation of resident precursor cells. High levels of Activin A were present in the upper epidermal layers and in the dermis of Lichen Planus biopsies in association with a marked infiltration of CD1a+ and Langerin+ cells. This study reports that Activin A induces the differentiation of circulating CD14+ cells into LC. Since Activin A is abundantly produced during inflammatory conditions which are also characterized by increased numbers of LC, we propose that this cytokine represents a new pathway, alternative to TGFbeta, responsible for LC differentiation during inflammatory/autoimmune conditions.

High frequency of immature dendritic cells and altered in situ production of interleukin-4 and tumor necrosis factor-alpha in lung cancer

INTRODUCTION

Antigen-presenting cells, like dendritic cells (DCs) and macrophages, play a significant role in the induction of an immune response and an imbalance in the proportion of macrophages, immature and mature DCs within the tumor could affect significantly the immune response to cancer. DCs and macrophages can differentiate from monocytes, depending on the milieu, where cytokines, like interleukin (IL)-4 and granulocyte-macrophage colony-stimulating factor (GM-CSF) induce DC differentiation and tumor necrosis factor (TNF)-alpha induce DC maturation. Thus, the aim of this work was to analyze by immunohistochemistry the presence of DCs (S100+ or CD1a+), macrophages (CD68+), IL-4 and TNF-alpha within the microenvironment of primary lung carcinomas.

RESULTS

Higher frequencies of both immature DCs and macrophages were detected in the tumor-affected lung, when compared to the non-affected lung. Also, TNF-alpha-positive cells were more frequent, while IL-4-positive cells were less frequent in neoplastic tissues. This decreased frequency of mature DCs within the tumor was further confirmed by the lower frequency of CD14-CD80+ cells in cell suspensions obtained from the same lung tissues analyzed by flow cytometry.

CONCLUSION

These data are discussed and interpreted as the result of an environment that does not oppose monocyte differentiation into DCs, but that could impair DC maturation, thus affecting the induction of effective immune responses against the tumor.

[Expression of toll-like receptors on CD14+ monocytes from patients with chronic obstructive pulmonary disease and smokers]

OBJECTIVE

To investigate the expression of toll-like receptor-2 (TLR2), TLR4 on the CD14+ monocytes of patients with stable chronic obstructive pulmonary disease (COPD) and healthy smokers, and to explore the role of TLR2 and TLR4 in COPD pathogenesis.

METHODS

Thirty COPD patients without evidence of acute exacerbation, 21 healthy smokers, and 25 healthy non-smokers underwent measurement of forced expiratory volume in 1 second (FEV(1))% predicted and FEV(1)/forced vital capacity (FVC) by spirometry. The expression of TLR2 and TLR4 surface molecules on human CD14+ monocytes was assessed using fluorescence activated cell sorter analysis by flow cytometry, expressed as relative mean fluorescence intensity (rmfi) and relative positive cell percent (rpcp), and the correlation of TLR expression with lung function parameters was analyzed.

RESULTS

The rmfi and rpcp of TLR2 on CD14+ monocytes of the COPD patients were (6.3 +/- 1.4)% and (52.9 +/- 20.5)% respectively, both significantly lower than those of the healthy smokers [(8.2 +/- 2.2)% and (73.5 +/- 19.0)% respectively] and those of the nonsmokers [(11.0 +/- 2.4)% and (82.8 +/- 17.9)% respectively, all P < 0.01)]. The rmfi of TLR4 of the COPD patients was 2.2 +/- 0.9, significantly lower than that of the nonsmokers (3.0 +/- 0.5, P < 0.01), while similar to that of the healthy smokers (2.5 +/- 0.6, P > 0.05). The rpcp of TLR4 of the COPD patients (M = 1.3%, Q(1) - Q(3): 0.7% - 2.4%) was significantly lower than that of the healthy smokers (M = 4.7%, Q(1) - Q(3): 2.7% - 9.4%, P < 0.01) and nonsmokers (M = 5.3%, Q(1) - Q(3): 2.6% - 8.4%, P < 0.01). The rmfi of TLR2 and TLR4 on CD14+ monocytes of the healthy smokers was lower than that of the nonsmokers (P < 0.05), while the rpcp of TLR2 and TLR4 on CD14+ monocytes of the healthy smokers was similar to that of the nonsmoker (P < 0.05). The expression of TLR2 and TLR4 on monocytes was positively correlated with the lung function parameters, including FEV(1)% predicted and FEV(1)/FVC (all P < 0.01).

CONCLUSIONS

The expression levels of TLR2 and TLR4 on CD14+ monocytes of the stable COPD patients and healthy smokers decreased significantly. The innate immune response may be depressed in the COPD patients and smokers, and the down-regulation of TLR is associated with reduced lung function parameters.

Sialoadhesin expressed on IFN-induced monocytes binds HIV-1 and enhances infectivity

Background

HIV-1 infection dysregulates the immune system and alters gene expression in circulating monocytes. Differential gene expression analysis of CD14⁺ monocytes from subjects infected with HIV-1 revealed increased expression of sialoadhesin (Sn, CD169, Siglec 1), a cell adhesion molecule first described in a subset of macrophages activated in chronic inflammatory diseases.

Methodology/Principal Findings

We analyzed sialoadhesin expression on CD14⁺ monocytes by flow cytometry and found significantly higher expression in subjects with elevated viral loads compared to subjects with undetectable viral loads. In cultured CD14⁺ monocytes isolated from healthy individuals, sialoadhesin expression was induced by interferon-α and interferon-γ but not tumor necrosis factor-α. Using a stringent binding assay, sialoadhesin-expressing monocytes adsorbed HIV-1 through interaction with the sialic acid residues on the viral envelope glycoprotein gp120. Furthermore, monocytes expressing sialoadhesin facilitated HIV-1 trans infection of permissive cells, which occurred in the absence of monocyte self-infection.

Conclusions/Significance

Increased sialoadhesin expression on CD14⁺ monocytes occurred in response to HIV-1 infection with maximum expression associated with high viral load. We show that interferons induce sialoadhesin in primary CD14⁺ monocytes, which is consistent with an antiviral response during viremia. Our findings suggest that circulating sialoadhesin-expressing monocytes are capable of binding HIV-1 and effectively delivering virus to target cells thereby enhancing the distribution of HIV-1. Sialoadhesin could disseminate HIV-1 to viral reservoirs during monocyte immunosurveillance or migration to sites of inflammation and then facilitate HIV-1 infection of permissive cells.

Characterization of cryopreserved CD14+-human monocytes after differentiation towards macrophages and stimulation with VEGF-A(165)

Monocytes are broadly discussed in the literature as cells, which can get properties of endothelial progenitor cells after angiogenic stimulation. Angiogenically stimulated monocytes can be used to promote implant vascularisation. A necessity therefore is that these cells can be stored and used after storage without a loose of their characteristic phenotype. In this study we tested, if freshly thawed cryopreserved human monocytes are positive for the mo/macrophage markers CD14 and CD68 and the endothelial marker CD31 after thawing and following angiogenic stimulation in a VEGF-A(165) enriched (10 ng/ml) angiogenic medium. Thereby the monocytes were tested before and after differentiation towards macrophages. The results revealed that freshly thawed human CD14 positive monocytes are positive for CD14, CD68 and CD31 after angiogenic stimulation. This CD specification was much more intense in the differentiated cells. The differentiation step also resulted in an increased cell count. Both results can be attributed to the method of differentiation, were cell culture bags were used instead of common cell culture dishes. Additionally the differentiation medium (X-VIVO 10+10% FCS) was specifically adapted to the requirements of monocytes/macrophages. The study showed that human CD14 positive monocytes can be thawed after cryopreservation without loss of their monocytes/macrophage phenotype and without loss of their ability to get angiogenically stimulated. To enhance the efficiency of both steps (thawing, angiogenic stimulation) it can be useful to differentiate the thawed cells in cell culture bags by the use of X-VIVO 10 (+10% FCS) before angiogenic stimulation.

Extracellular branched-chain amino acids, especially valine, regulate maturation and function of monocyte-derived dendritic cells

The functions of dendritic cells (DCs) are impaired in patients with liver cirrhosis. It is well-known that cirrhotic patients show decreased levels of plasma branched-chain amino acids (BCAA). Although amino acids are associated with maintaining the cell structure and function in many organs, limited data are available regarding the role of amino acids including BCAA in the immune system. We aimed to investigate the roles of BCAA in the function of human monocyte-derived DCs (MoDC). CD14-positive monocytes (CD14 (+)) were isolated from PBMC from healthy volunteers and hepatitis C virus (HCV) cirrhotic patients. In medium deprived of BCAA or valine, monocytes were able to differentiate into immature, but not into mature, DCs and showed weak expression of CD83. The deprivation of leucine or isoleucine did not affect this process. The MoDC allostimulatory capacity was significantly decreased in medium deprived of BCAA or valine (p = 0.017, p = 0.012, Bonferroni's analysis, respectively). Annexin V(FITC)/propidium iodide staining showed that the DC yield and viability were not significantly different under any medium. Immunoblotting demonstrated that depletion of valine or leucine decreased phospho-S6 kinase expression. Valine increased dose-dependently the allostimulatory capacity and IL-12 production of MoDC from both healthy volunteers and HCV cirrhotic patients. An elevated extracellular concentration of valine could improve the DC function in cirrhotic patients. These data provide a rationale for nutrition therapy that could be beneficial to patients with cirrhosis.

Frequent detection of cell-associated HIV-1 RNA in patients with plasma viral load <50 copies/ml

Despite prolonged undetectable plasma viral load some HIV-1 infected patients have been reported to develop resistance-associated mutations leading to treatment failure. The mechanisms for this phenomenon and the point of origin for residual viral evolution are still not elucidated. In order to quantify cell-associated HIV-1 RNA in patients with different levels of plasma viremia paired cell-associated HIV-1 RNA loads and plasma viral loads were determined. Weak inverse correlation between these parameters and the amounts of CD4(+) T cells was observed, whereas there was no correlation between viral loads and CD8(+) T cells or CD14(+) monocytes, respectively. In a subset of patients, cell-associated and plasma HIV-1 env V3 sequences were analyzed. Plasma viral load and the amount of cell-associated HIV-RNA correlated strongly. However, in 62.3% of patients with undetectable plasma viral load cell-associated HIV-RNA could be detected. Analyses of HIV-RNA in plasma and blood cells showed identical sequences in 4/19 patients, whereas the majority of patients had differing HIV-1 RNA sequences in plasma and cells, respectively. In summary, this study shows that residual viral replication in peripheral blood still occurs in the majority of patients with undetectable plasma viral load. Since these replication events could lead to ongoing viral evolution it should be considered to optimize antiretroviral therapy in order to minimize the development of drug resistance.

Morphine inhibits AP-1 activity and CD14 expression in leukocytes by a nitric oxide and opioid receptor-dependent mechanism

BACKGROUND

Activator protein 1 is a transcription factor involved in the regulation of proinflammatory mediators. Activation of phagocytes by lipopolysaccharide depends on the expression of CD14 on the cell surface. In this study, we investigated the effects of morphine and nitric oxide on CD14 expression and activator protein 1 activation in human blood monocytes and neutrophils as well as the leukocyte cell line HL-60.

METHODS

Whole blood was incubated with morphine, the nitric oxide donor S-nitroso-N-acetyl-penicillamine, naloxone or nitric oxide synthase inhibitors Nomega-nitro-l-arginine and Nomega-nitro-l-arginine-methylester and stimulated with lipopolysaccharide. Activator protein 1 nuclear content was determined by flow cytometry in human blood neutrophils and monocytes. CD14 expression on neutrophils was measured after incubation with fluorescein isothiocyanate-labelled antibodies. Electric mobility shift assay served for evaluation of activator protein 1 nuclear binding in HL-60 cells.

RESULTS

Incubation of whole blood with morphine and subsequent stimulation with lipopolysaccharide decreased activator protein 1 nuclear content. Exposure to naloxone before morphine treatment abolished morphine-induced inhibition of activator protein 1 activity in human blood monocytes and neutrophils. Nitric oxide synthase inhibitors also reversed morphine's effects. CD14 expression on neutrophils was reduced after morphine treatment. These effects were antagonized by nitric oxide synthase inhibitors and naloxone.

CONCLUSION

Morphine inhibits activator protein 1 activation by a mu opioid receptor pathway coupled to nitric oxide as second messenger. The decrease in CD14 expression caused by morphine may play a role in inhibition of activator protein 1 activation following lipopolysaccharide treatment of phagocytes.

A polymorphism in CD14 modifies the effect of farm milk consumption on allergic diseases and CD14 gene expression

BACKGROUND

Consumption of farm milk in early life is associated with less asthma and allergies.

OBJECTIVE

We hypothesized that genetic variation in the innate immunity receptor CD14 might modify the association between farm milk consumption and asthma and atopy.

METHODS

Questionnaire data, serum IgE levels, and genotypes for 4 single nucleotide polymorphisms in CD14 were assessed in farmers' and nonfarmers' children from 2 European populations (Allergy and Endotoxin study, n = 576; Prevention of Allergy Risk factors for Sensitization in children related to Farming and Anthroposophic Lifestyle study, n = 1539). In a subsample (n = 222) CD14 gene expression was measured in peripheral blood leukocytes. The effects of farm milk and CD14 genotypes on asthma, allergies, and CD14 expression and their interactions were investigated.

RESULTS

We found a significant interaction between genetic variation in CD14/-1721 and farm milk consumption. Adjusted odds ratios for the association between farm milk and asthma varied between the genotypes: AA, 0.18 (95% CI, 0.07-0.47); AG, 0.47 (95% CI, 0.26-0.86); and GG, 0.98 (95% CI, 0.46-2.08). Similar patterns were observed for symptoms of allergic rhinoconjunctivitis and pollen sensitization. CD14/-1721 also modified the association between farm milk and CD14 gene expression (adjusted geometric means ratios: AA, 1.61 (95% CI, 0.98-2.66); AG, 1.11 (95% CI, 0.71-1.72); and GG, 0.76 (95% CI, 0.39-1.48).

CONCLUSION

The protective effect of farm milk consumption on allergic diseases is stronger in children carrying the A allele in CD14/-1721 than in children homozygous for the G allele. This might be mediated through farm milk-induced upregulated CD14 gene expression.

CLINICAL IMPLICATIONS

Our results support the hypothesis that the inverse association between farm milk consumption and allergic diseases is mediated by CD14-activated innate immune mechanisms.