Effect of simultaneous activation of TGFbeta and TLR4 pathway in human monocytes
ABSTRACT: To better understand the interaction of TGFbeta and Toll-like-receptor 4 (TLR4) signaling in monocytes, we performed microarray analysis. We identified a unique set of genes whose expressions in monocytes were regulated by simultaneous stimulation of TLR4 and TGFβ signaling. THP-1 cells, a human monocytic cell line, were stimulated for 24 hours with PBS as control, LPS (100ng/ml), TGFbeta1 (1ng/ml) or LPS (100ng/ml) + TGFbeta1 (1ng/ml). After 24 hours of stimulation, total RNA was isolated and prepared for genome wide analyses using Illumina HumanRef8 V3.0 Beadchips. In total 32 arrays were analyzed including 8 samples of PBS-stimulated monocytes, 8 samples of LPS-stimulated monocytes, 8 samples of TGFbeta1 stimulated monocytes and 8 samples of monocytes stimulated with LPS + TGFbeta1.
Project description:To better understand the interaction of TGFbeta and Toll-like-receptor 4 (TLR4) signaling in monocytes, we performed microarray analysis. We identified a unique set of genes whose expressions in monocytes were regulated by simultaneous stimulation of TLR4 and TGFβ signaling. Overall design: THP-1 cells, a human monocytic cell line, were stimulated for 24 hours with PBS as control, LPS (100ng/ml), TGFbeta1 (1ng/ml) or LPS (100ng/ml) + TGFbeta1 (1ng/ml). After 24 hours of stimulation, total RNA was isolated and prepared for genome wide analyses using Illumina HumanRef8 V3.0 Beadchips. In total 32 arrays were analyzed including 8 samples of PBS-stimulated monocytes, 8 samples of LPS-stimulated monocytes, 8 samples of TGFbeta1 stimulated monocytes and 8 samples of monocytes stimulated with LPS + TGFbeta1.
Project description:Consumption of a diet rich in cruciferous vegetables is associated with decreased risk of developing non-communicable chronic disease. It has been proposed that biologically active isothiocyanates (ITCs) obtained from these vegetables, such as sulforaphane (SF) derived from broccoli, are responsible for mediating health benefits via multiple mechanisms of action. ITCs have been shown to suppress the levels of several LPS-induced pro-inflammatory cytokines that are biomarkers for chronic inflammatory conditions, and which have been associated with the development of both cancer and cardiovascular disease. In patients suffering from chronic inflammatory diseases, LPS is elevated in circulation to levels reaching around 1ng/ml. In the current study, we demonstrate that SF suppresses global changes in gene expression induced by LPS exposure (1ng/ml) in human THP-1 cells at a physiologically achievable concentration of 5 micromolar. These results illustrate the profound effect that SF can have at concentrations achievable through the consumption of broccoli in suppressing TLR4-mediated inflammatory pathways.
Project description:IL-1? release is integral to the innate immune system. The release of mature IL-1? depends on 2 regulated events: the de novo induction of pro-IL-1?, generally via NF-?B-dependent transduction pathways; and the assembly and activation of the NLRP3 inflammasome. This latter step is reliant on active caspase-1, pannexin-1, and P2X7 receptor activation. Pathogen-associated molecular patterns in gram-positive and gram-negative bacteria activate IL-1? release from immune cells via TLR2 and TLR4 receptors, respectively. We found that pro-IL-1? and mature IL-1? release from human monocytes is stimulated by the TLR2 agonists Pam3CSK4 or FSL-1, as well as the TLR4 agonist LPS in the absence of additional ATP. TLR2 agonists required pannexin-1 and P2X7 receptor activation to stimulate IL-1? release. In contrast, IL-1? release stimulated by the TLR4 agonist LPS is independent of both pannexin-1 and P2X7 activation. In the absence of exogenous ATP, P2X7 activation requires endogenous ATP release, which occurs in some cells via pannexin-1. In line with this, we found that LPS-stimulated human monocytes released relatively low levels of ATP, whereas cells stimulated with TLR2 agonists released high levels of ATP. These findings suggest that in human monocytes, both TLR2 and TLR4 signaling induce pro-IL-1? expression, but the mechanism by which they activate caspase-1 diverges at the level of the pannexin-1/ATP/P2X7 axis.-Parzych, K., Zetterqvist, A. V., Wright, W. R., Kirkby, N. S., Mitchell, J. A., Paul-Clark, M. J. Differential role of pannexin-1/ATP/P2X7 axis in IL-1? release by human monocytes.
Project description:BACKGROUND:Surfactant replacement therapy is the standard of care for the prevention and treatment of neonatal respiratory distress syndrome. New generation synthetic surfactants represent a promising alternative to animal-derived surfactants. CHF5633, a new generation reconstituted synthetic surfactant containing SP-B and SP-C analogs and two synthetic phospholipids has demonstrated biophysical effectiveness in vitro and in vivo. While several surfactant preparations have previously been ascribed immunomodulatory capacities, in vitro data on immunomodulation by CHF5633 are limited, so far. Our study aimed to investigate pro- and anti-inflammatory effects of CHF5633 on native and LPS-stimulated human adult monocytes. METHODS:Highly purified adult CD14+ cells, either native or simultaneously stimulated with LPS, were exposed to CHF5633, its components, or poractant alfa (Curosurf®). Subsequent expression of TNF-?, IL-1?, IL-8 and IL-10 mRNA was quantified by real-time quantitative PCR, corresponding intracellular cytokine synthesis was analyzed by flow cytometry. Potential effects on TLR2 and TLR4 mRNA and protein expression were monitored by qPCR and flow cytometry. RESULTS:Neither CHF5633 nor any of its components induced inflammation or apoptosis in native adult CD14+ monocytes. Moreover, LPS-induced pro-inflammatory responses were not aggravated by simultaneous exposure of monocytes to CHF5633 or its components. In LPS-stimulated monocytes, exposure to CHF5633 led to a significant decrease in TNF-? mRNA (0.57 ± 0.23-fold, p = 0.043 at 4h; 0.56 ± 0.27-fold, p = 0.042 at 14h). Reduction of LPS-induced IL-1? mRNA expression was not significant (0.73 ± 0.16, p = 0.17 at 4h). LPS-induced IL-8 and IL-10 mRNA and protein expression were unaffected by CHF5633. For all cytokines, the observed CHF5633 effects paralleled a Curosurf®-induced modulation of cytokine response. TLR2 and TLR4 mRNA and protein expression were not affected by CHF5633 and Curosurf®, neither in native nor in LPS-stimulated adult monocytes. CONCLUSION:The new generation reconstituted synthetic surfactant CHF5633 was tested for potential immunomodulation on native and LPS-activated adult human monocytes. Our data confirm that CHF5633 does not exert unintended pro-inflammatory effects in both settings. On the contrary, CHF5633 significantly suppressed TNF-? mRNA expression in LPS-stimulated adult monocytes, indicating potential anti-inflammatory effects.
Project description:Oxidative stress is a hallmark of inflammation in infection or sterile tissue injury. We show that partially oxidized phospholipids of microvesicles (MVs) from plasma of patients with rheumatoid arthritis or cells exposed to oxidative stress induce activation of TLR4. MVs from healthy donors or reconstituted synthetic MVs can be converted to TLR4 agonists by limited oxidation, while prolonged oxidation abrogates the activity. Activation by MVs mimics the mechanism of TLR4 activation by LPS. However, LPS and MVs induce significantly different transcriptional response profile in mouse BMDMs with a strong inflammation-resolving component induced by the endogenous signals. MVs thus represent a ubiquitous endogenous danger signal released under the oxidative stress, which underlies the pervasive role of TLR4 signaling in inflammation. Overall design: BMDMs (bone marrow derived macrophages) from C57BL/6J strain were stimulated with LPS (100ng/ml), oxidative stress-derived MVs (5000 MV/ml) or MVs-FR (5000 MV/ml). RNA was extracted 4 hours after stimulation. 3 biological replicates (BMDM cells isolated from three different mice) per group.
Project description:Genetic variants and dysfunctional monocyte had been reported to be associated with infection susceptibility in advanced cirrhotic patients. This study aims to explore genetic predictive markers and relevant immune dysfunction that contributed to severe sepsis in febrile acute de-compensated cirrhotic patents. Polymorphism analysis of candidate genes was undergone in 108 febrile acute de-compensated cirrhotic patients and 121 healthy volunteers. Various plasma inflammatory/regulatory cytokines, proportion of classical (CD 16-, phagocytic) and non-classical (CD16+, inflammatory) monocytes, lipopolysaccharide (LPS)-stimulated toll-like receptor 4 (TLR4) and intracellular/extracellular cytokines on cultured non-classical monocytes, mCD14/HLA-DR expression and phagocytosis of classical monocytes were measured. For TLR4+896A/G variant allele carriers with severe sepsis, high plasma endotoxin/IL-10 inhibits HLA-DR expression and impaired phagocytosis were noted in their classical monocyte. In the same group, increased non-classical monocyte subset, enhanced LPS-stimulated TLR4 expression and TNF?/nitrite production, and systemic inflammation [high plasma soluble CD14 (sCD14) and total nitric oxide (NOx) levels] were noted. For CD14-159C/T variant allele carriers with severe sepsis, persist endotoxemia inhibited mCD14/HLA-DR expression and impaired phagocytosis of their classical monocyte. In the same group, increased non-classical monocyte subset up-regulated TLR4-NF?B-iNOS and p38MAPK pathway, stimulated TNF?/nitrite production and elicited systemic inflammation. In febrile acute de-compensated cirrhotic patients, TLR4+896A/G and CD14-159C/T polymorphisms-related non-classical and classical monocytes dysfunction resulted in increased severe sepsis risk. Malnutrition, high plasma endotoxin and sCD14 levels, single TLR4+896A/G or CD14-159C/T variant allele carriers and double variant allele carriers are significant predictive factors for the development of severe sepsis among them.
Project description:OBJECTIVE:The root cause behind the low-grade inflammatory state seen in insulin resistant (obesity and type 2 diabetes) states is unclear. Insulin resistant subjects have elevations in plasma free fatty acids (FFA), which are ligands for the pro-inflammatory toll-like receptor (TLR)4 pathway. We tested the hypothesis that an experimental elevation in plasma FFA (within physiological levels) in lean individuals would upregulate TLR4 and activate downstream pathways (e.g., MAPK) in circulating monocytes. RESEARCH DESIGN AND METHODS:Twelve lean, normal glucose-tolerant subjects received a low dose (30 ml/h) 48 h lipid or saline infusion on two different occasions. Monocyte TLR4 protein level, MAPK phosphorylation, and expression of genes in the TLR pathway were determined before and after each infusion. RESULTS:The lipid infusion significantly increased monocyte TLR4 protein and phosphorylation of JNK and p38 MAPK. Lipid-mediated increases in TLR4 and p38 phosphorylation directly correlated with reduced peripheral insulin sensitivity (M value). Lipid increased levels of multiple genes linked to inflammation, including several TLRs, CD180, MAP3K7, and CXCL10. Monocytes exposed in vivo to lipid infusion exhibited enhanced in vitro basal and LPS-stimulated IL-1? secretion. CONCLUSIONS:In lean subjects, a small increase in plasma FFA (as seen in insulin resistant subjects) is sufficient to upregulate TLR4 and stimulate inflammatory pathways (MAPK) in monocytes. Moreover, lipids prime monocytes to endotoxin. We provide proof-of-concept data in humans indicating that the low-grade inflammatory state characteristic of obesity and type 2 diabetes could be caused (at least partially) by pro-inflammatory monocytes activated by excess lipids present in these individuals.
Project description:Samples of monocyte derived dendritic cells (moDCs) from three healthy volunteers untreated and treated with LPS [100ng/ml] or R848 [2.5µg/ml] for different time points (0h,3h,6h,12h and 24h).
Project description:Damage-associated molecular patterns (DAMPs) are endogenous molecules activating the immune system upon release from injured cells. Here we show that the IFI16 protein, once freely released in the extracellular milieu of chronically inflamed tissues, can function as a DAMP either alone or upon binding to lipopolysaccharide (LPS). Specifically, using pull-down and saturation binding experiments, we show that IFI16 binds with high affinity to the lipid A moiety of LPS. Remarkably, IFI16 DAMP activity is potentiated upon binding to subtoxic concentrations of strong TLR4-activating LPS variants, as judged by TLR4-MD2/TIRAP/MyD88-dependent IL-6, IL-8 and TNF-? transcriptional activation and release in stimulated monocytes and renal cells. Consistently, using co-immunoprecipitation (co-IP) and surface plasmon resonance (SPR) approaches, we show that IFI16 is a specific TLR4-ligand and that IFI16/LPS complexes display a faster stimulation turnover on TLR4 than LPS alone. Altogether, our findings point to a novel pathomechanism of inflammation involving the formation of multiple complexes between extracellular IFI16 and subtoxic doses of LPS variants, which then signal through TLR4.
Project description:The effect of lutropin on phosphorylation of endogenous proteins in testis Leydig cells was investigated, by incubating purified Leydig cells with lutropin and [(32)P]P(i) followed by sodium dodecyl sulphate/polyacrylamide-slab gel electrophoresis of the [(32)P]phosphoproteins. The radioactivity of the proteins was quantified by densitometry of the radio-autograms obtained. The following results were obtained. 1. Lutropin increased the amount of (32)P incorporated into three proteins (A, B and C) with apparent mol.wts. of 14300, 57000 and 77600 respectively. 2. The increase in incorporation of (32)P into these proteins was detectable within 5min, reaching a maximum in approx. 20min. 3. The (32)P incorporated into protein B (but not proteins A and C) was significantly increased with 0.1 and 1.0ng of lutropin/ml. Incorporation of (32)P into all three proteins was significantly increased with 10ng of lutropin/ml, reaching a maximum with 100ng/ml. 4. Testosterone production was significantly increased with 1ng of lutropin/ml, and between 10 and 1000ng/ml the degree of stimulation of testosterone production and incorporation of (32)P into proteins A, B and C was similar. 5. Cyclic AMP production was significantly increased with 10ng of lutropin/ml and had not reached a maximum with 1000ng/ml. 6. In Leydig cells isolated from hypophysectomized rats 3h after injection of choriogonadotropin in vivo, phosphoproteins with the same molecular weights as proteins A, B and C were found. No further increases in incorporation of (32)P into these proteins were obtained when lutropin was added to the Leydig cells in vitro. 7. Dibutyryl cyclic AMP (but not follitropin or testosterone) also stimulated the incorporation of (32)P into proteins A, B and C in Leydig cells.