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PloS One 2012Human blood monocytes play a central role in dengue infections and form the majority of virus infected cells in the blood. Human blood monocytes are heterogeneous and...
Human blood monocytes play a central role in dengue infections and form the majority of virus infected cells in the blood. Human blood monocytes are heterogeneous and divided into CD16(-) and CD16(+) subsets. Monocyte subsets play distinct roles during disease, but it is not currently known if monocyte subsets differentially contribute to dengue protection and pathogenesis. Here, we compared the susceptibility and response of the human CD16(-) and CD16(+) blood monocyte subsets to primary dengue virus in vitro. We found that both monocyte subsets were equally susceptible to dengue virus (DENV2 NGC), and capable of supporting the initial production of new infective virus particles. Both monocyte subsets produced anti-viral factors, including IFN-α, CXCL10 and TRAIL. However, CD16(+) monocytes were the major producers of inflammatory cytokines and chemokines in response to dengue virus, including IL-1β, TNF-α, IL-6, CCL2, 3 and 4. The susceptibility of both monocyte subsets to infection was increased after IL-4 treatment, but this increase was more profound for the CD16(+) monocyte subset, particularly at early time points after virus exposure. These findings reveal the differential role that monocyte subsets might play during dengue disease.
Topics: Cell Survival; Chemokines; Dengue Virus; Humans; Interleukin-4; Monocytes; Receptors, IgG; Solubility
PubMed: 22574162
DOI: 10.1371/journal.pone.0036435 -
Journal of Cardiovascular Translational... Aug 2013B-type natriuretic peptide (BNP) is a prognostic and diagnostic marker for heart failure (HF). An anti-inflammatory, cardio-protective role for BNP was proposed. In...
B-type natriuretic peptide (BNP) is a prognostic and diagnostic marker for heart failure (HF). An anti-inflammatory, cardio-protective role for BNP was proposed. In cardiovascular diseases including pressure overload-induced HF, perivascular inflammation and cardiac fibrosis are, in part, mediated by monocyte chemoattractant protein (MCP)1-driven monocyte migration. We aimed to determine the role of BNP in monocyte motility to MCP1. A functional BNP receptor, natriuretic peptide receptor-A (NPRA) was identified in human monocytes. BNP treatment inhibited MCP1-induced THP1 (monocytic leukemia cells) and primary monocyte chemotaxis (70 and 50 %, respectively). BNP did not interfere with MCP1 receptor expression or with calcium. BNP inhibited activation of the cytoskeletal protein RhoA in MCP1-stimulated THP1 (70 %). Finally, BNP failed to inhibit MCP1-directed motility of monocytes from patients with hypertension (n = 10) and HF (n = 6) suggesting attenuation of this anti-inflammatory mechanism in chronic heart disease. We provide novel evidence for a direct role of BNP/NPRA in opposing human monocyte migration and support a role for BNP as a cardio-protective hormone up-regulated as part of an adaptive compensatory response to combat excess inflammation.
Topics: Aged; Aged, 80 and over; Anti-Inflammatory Agents; Calcium; Cell Line, Tumor; Chemokine CCL2; Chemotaxis, Leukocyte; Dose-Response Relationship, Drug; Female; Heart Failure; Humans; Hypertension; Male; Middle Aged; Monocytes; Natriuretic Peptide, Brain; Receptors, Atrial Natriuretic Factor; Receptors, CCR2; Signal Transduction; Time Factors; rhoA GTP-Binding Protein
PubMed: 23625718
DOI: 10.1007/s12265-013-9456-1 -
International Journal of Molecular... Sep 2018Monocytes/macrophages are important in orchestrating inflammatory responses. However, knowledge of the long noncoding RNA (lncRNA) regulation of monocytic cell...
Monocytes/macrophages are important in orchestrating inflammatory responses. However, knowledge of the long noncoding RNA (lncRNA) regulation of monocytic cell differentiation and diseases remains limited. We aimed to elucidate the role of the 17 kb lncRNA noncoding transcript in T cells () in monocyte functions. Knockdown and chromatin immunoprecipitation (ChIP) assays in THP-1 cells (human monocytic leukemia cell line) revealed that is regulated by the monocyte key transcription factor C/EBPβ and that it binds to the promoter of nearby gene via hnRNP-U. Overexpression of in THP-1 cells resulted in cell cycle G1 arrest, differentiation into macrophages, a marked increase in and mRNA levels, and upregulation of the costimulatory molecules. In contrast to the downregulated observed in lipopolysaccharide (LPS)-treated THP-1 cells, the axis was found to be hyperactivated in peripheral blood mononuclear cells (PBMCs) of first-time diagnosed untreated early rheumatoid arthritis (RA) patients, and their gene expression levels decreased markedly after treatment. Higher initial expression levels were associated with a trend of higher disease activity DAS28 scores. In conclusion, our study suggests that the lncRNA is a regulator of inflammation in monocytes, and its activation participates in monocyte/macrophage differentiation and the pathogenesis of RA.
Topics: Adult; Aged; Arthritis, Rheumatoid; Cell Cycle Checkpoints; Cell Differentiation; Cells, Cultured; Down-Regulation; Female; Humans; Inflammation; Macrophages; Male; Middle Aged; Monocytes; Neoplasm Proteins; RNA, Long Noncoding; Up-Regulation
PubMed: 30231487
DOI: 10.3390/ijms19092806 -
The British Journal of Dermatology Oct 1992Anthralin is a well-established and widely used compound for topical treatment of psoriasis. In recent years attention has been focused on the anti-inflammatory... (Comparative Study)
Comparative Study
Anthralin is a well-established and widely used compound for topical treatment of psoriasis. In recent years attention has been focused on the anti-inflammatory properties of anthralin, with particular reference to psoriasis. In this study the effect of anthralin on human monocyte chemotaxis, superoxide-anion generation, and enzyme degranulation, were investigated. For comparison, the effect of the clinically inactive anthralin derivative danthrone and the solvent (acetone) were also studied. The results show that anthralin potently inhibits stimulated human monocyte superoxide-anion generation and enzyme degranulation, with a half-maximal inhibitory concentration (IC50) of as low as 0.02 micrograms/ml. Chemotactic migration of monocytes, however, was only affected when very high doses of anthralin (10 micrograms/ml) were used for pretreatment of the cells. Danthrone, up to a concentration of 10 micrograms/ml, or acetone alone (0.1%, v/v), did not inhibit the monocyte functions tested. Our results indicate that anthralin at pharmacological concentrations is a potent and selective inhibitor of human monocyte pro-inflammatory activities, by inhibiting respiratory burst activity (e.g. superoxide-anion generation) and enzyme degranulation, without affecting chemotactic migration.
Topics: Acetone; Anthralin; Anthraquinones; Cell Degranulation; Chemotaxis, Leukocyte; Depression, Chemical; Glucuronidase; Humans; Monocytes; Respiratory Burst; Superoxides
PubMed: 1329912
DOI: 10.1111/j.1365-2133.1992.tb00458.x -
Biochemical and Biophysical Research... Sep 2007For rapid chemotaxis quantification, cell prelabelling is often performed with the fluorochrome calcein acetomethylester (calcein AM). We investigated whether calcein...
For rapid chemotaxis quantification, cell prelabelling is often performed with the fluorochrome calcein acetomethylester (calcein AM). We investigated whether calcein AM-prelabelling is reliable for monocyte migration analysis. Human monocytes were either preexposed to calcein AM or unlabelled. Monocyte migration towards the potent chemoattractants transforming growth factor-beta1 (TGF-beta1) and N-formyl-Methionin-Leucin-Phenylalanin (fMLP) was assessed using a 48-well micro-chemotaxis chamber. For quantification, cells were visualized by light microscopy and counted. Surprisingly, random migration of calcein AM-prelabelled cells was significantly impaired compared to the unlabelled control. Accordingly, monocyte chemotaxis towards either TGF-beta1 or fMLP dramatically declined. Adherence of calcein AM-labelled monocytes on plastic was also significantly decreased compared to control cells. As adhesion is regarded as an essential component of monocyte migration, the reduced migration observed in calcein AM-labelled monocytes might be explained by a fluorochrome-induced adhesion defect. Therefore, use of the fluorochrome calcein AM cannot be recommended for functional testing of monocytes.
Topics: Cell Adhesion; Cell Movement; Cell Size; Cell Survival; Fluoresceins; Fluorescent Dyes; Humans; Monocytes
PubMed: 17645867
DOI: 10.1016/j.bbrc.2007.07.018 -
Frontiers in Immunology 2021Monocytes are the third most frequent type of leukocytes in humans, linking innate and adaptive immunity and are critical drivers in many inflammatory diseases. Based on...
Monocytes are the third most frequent type of leukocytes in humans, linking innate and adaptive immunity and are critical drivers in many inflammatory diseases. Based on the differential expression of surface antigens, three monocytic subpopulations have been suggested in humans and two in rats with varying inflammatory and phenotype characteristics. Potential intervention strategies that aim to manipulate these cells require an in-depth understanding of monocyte behavior under different conditions. However, monocytes are highly sensitive to their specific activation state and expression of surface markers, which can change during cell isolation and purification. Thus, there is an urgent need for an unbiased functional analysis of activation in monocyte subtypes, which is not affected by the isolation procedure. Here, we present a flow cytometry-based protocol for evaluating subset-specific activation and cytokine expression of circulating blood monocytes both in humans and rats using small whole blood samples (50 - 100 μL). In contrast to previously described monocyte isolation and flow cytometry visualization methods, the presented approach virtually leaves monocyte subsets in a resting state or fixes them in their current state and allows for an unbiased functional endpoint analysis without prior cell isolation. This protocol is a comprehensive tool for studying differential monocyte regulation in the inflammatory and allogeneic immune response and .
Topics: Adult; Animals; Cytokines; Female; Flow Cytometry; Humans; Male; Monocytes; Rats; Rats, Wistar
PubMed: 33981302
DOI: 10.3389/fimmu.2021.641224 -
Frontiers in Immunology 2021Elevated blood lactate levels are frequently found in critically ill patients and thought to result from tissue hypoperfusion and cellular oxygen shortage. Considering...
Elevated blood lactate levels are frequently found in critically ill patients and thought to result from tissue hypoperfusion and cellular oxygen shortage. Considering the close relationship between immune cell function and intracellular metabolism, lactate is more than a glycolytic waste molecule but able to regulate the immune response. Our aim was to elucidate the temporal and mechanistic effect of extracellular lactate on monocytes. To this end, primary human monocytes and the human monocytic cell line MonoMac6 were stimulated with various toll-like-receptor agonists after priming with Na-L-lactate under constant pH conditions. As readout, cytokine production was measured, real-time assessment of intracellular energy pathways was performed, and intracellular metabolite concentrations were determined. Irrespective of the immunogenic stimulus, short-term Na-lactate-priming strongly reduced cytokine production capacity. Lactate and hexoses accumulated intracellularly and, together with a decreased glycolytic flux, indicate a lactate-triggered impairment of glycolysis. To counteract intracellular hyperglycemia, glucose is shunted into the branching polyol pathway, leading to sorbitol accumulation. In contrast, long-term priming with Na-L-lactate induced cellular adaption and abolished the suppressive effect. This lactate tolerance is characterized by a decreased cellular respiration due to a reduced complex-I activity. Our results indicate that exogenous lactate shapes monocyte function by altering the intracellular energy metabolism and acts as a metabolic checkpoint of monocyte activation.
Topics: Cell Line; Extracellular Fluid; Humans; Lactic Acid; Monocytes
PubMed: 34899690
DOI: 10.3389/fimmu.2021.729209 -
Journal of Proteome Research Jul 2016Innate immune cells are complex systems that can be simultaneously activated in a variety of ways. Common methods currently used to estimate the response of innate...
Innate immune cells are complex systems that can be simultaneously activated in a variety of ways. Common methods currently used to estimate the response of innate immune cells to stimuli are usually biased toward a single mode of activation. The aim of this study was to assess the possibility of designing an assay based on unbiased proteome analysis that would be capable of predicting the complex response of the innate immune system to various challenges. Monocytes were used as representative cells of the innate immune system. The underlying hypothesis was that their proteome response to different activating molecules would reflect the immunogenicity of these molecules. To identify the main modes of response, we treated the human monocytic THP-1 cell line with nine different stimuli. Differentiation and activation were determined to be the two major modes of monocyte response, with PMA causing the strongest differentiation and Pam3CSK4 causing the strongest proinflammatory activation. The established assay was applied to characterize the monocyte response to epidermal growth factor peptide containing isoaspartate, which induced differentiation but not proinflammatory activation. Because of its versatility, robustness, and specificity, this new assay is likely to find a niche among the more established immunological methods.
Topics: Cell Line; Epidermal Growth Factor; Humans; Immunity, Innate; Lipopeptides; Monitoring, Immunologic; Monocytes; Proteome; Proteomics; Tetradecanoylphorbol Acetate
PubMed: 27223872
DOI: 10.1021/acs.jproteome.6b00422 -
Cytometry. Part a : the Journal of the... Apr 2006Monocyte subsets are not well defined in murine peripheral blood (PB). Monocyte-related populations could also be located in bone marrow (BM), but studies correlating...
BACKGROUND
Monocyte subsets are not well defined in murine peripheral blood (PB). Monocyte-related populations could also be located in bone marrow (BM), but studies correlating monocyte populations found in these two tissues are lacking. This study simultaneously analyzed PB and BM to phenotypically define multiple monocyte-related subsets in each location.
METHODS
Murine PB and BM cells were simultaneously stained for monocyte-related populations, using five-color flow cytometry. Relevant subsets were defined on the basis of Ly-6C, CD11b, and wheat germ agglutinin phenotype in addition to light-scatter characteristics. These populations were extensively characterized for the expression of other myeloid and dendritic cell markers, adhesion molecules, chemokine receptors, and growth factor receptors.
RESULTS
Six monocyte-related populations were defined, three each in BM and PB. No identical populations were found between the two tissues. Two BM populations and one PB population have heterogeneous expression of many markers, suggesting additional complexity among monocyte-related subsets.
CONCLUSIONS
The murine monocytic series comprises multiple subsets, differing between PB and BM. This study defines and extensively phenotypes six of these populations, providing preliminary information about possible developmental relationships and migratory capacities of these cells.
Topics: Animals; Antigens, Ly; Biomarkers; CD11b Antigen; Flow Cytometry; Mice; Mice, Congenic; Mice, Inbred C57BL; Monocytes; Phenotype; Specific Pathogen-Free Organisms; Wheat Germ Agglutinins
PubMed: 16528720
DOI: 10.1002/cyto.a.20262 -
PloS One 2012The leading cause of pregnancy-associated mortality and morbidity is pre-eclampsia (PE). Although information regarding the etiology of this disease is scant, its...
The leading cause of pregnancy-associated mortality and morbidity is pre-eclampsia (PE). Although information regarding the etiology of this disease is scant, its pathophysiology is characterized by abnormal placentation, endothelial dysfunction as well as an exaggerated inflammatory response. Clinical evidence also indicates that the abundance of many immune cells at the feto-maternal interface and in the circulation of PE patients is abnormal, when compared with normal pregnant (NP) controls. In addition, the phenotype and function of some of these cells is altered. To further characterize the systemic effects of PE on circulating cells, we analyzed monocytic subpopulations in NP and PE patients by flow cytometry. We found that non-classical CD14(low)CD16(+) monocytes are significantly increased in women with PE and they display irregular expression of several chemokine receptors and antigen presentation molecules. The most striking phenotypic difference among the cell surface molecules was the marked upregulation of TLR4 expression, where both CD14(high)CD16(+) and CD14(low)CD16(+) monocytes demonstrated higher levels than their NP counterparts. Stimulation of PE monocytes with TLR ligands resulted in profound secretion of various cytokines in comparison with NP controls. These data suggest that PE monocytes are hyper-responsive to TLR ligands and this may contribute to exacerbation of the disease.
Topics: Adult; Case-Control Studies; Female; Gene Expression Regulation; Humans; Ligands; Lipopolysaccharide Receptors; Monocytes; Phenotype; Pre-Eclampsia; Pregnancy; Receptors, IgG; Toll-Like Receptors
PubMed: 22848746
DOI: 10.1371/journal.pone.0042217