Comparison of SP-A and LPS effects on the THP-1 monocytic cell line

2000 ◽  
Vol 279 (1) ◽  
pp. L110-L117 ◽  
Author(s):  
Mingchen Song ◽  
David S. Phelps
Keyword(s):  
Protein A ◽  
Surfactant Protein ◽  
Polymyxin B ◽  
Inhibitory Effects ◽  
Monocytic Cell ◽  
Monocytic Cell Line ◽  
Monocytic Cells ◽  
Similar Treatment ◽  
Tnf Α ◽  
Factor Α

Surfactant protein A (SP-A) increases production of proinflammatory cytokines by monocytic cells, including THP-1 cells, as does lipopolysaccharide (LPS). Herein we report differences in responses to these agents. First, polymyxin B inhibits the LPS response but not the SP-A response. Second, SP-A-induced increases in tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-8 are reduced by >60% if SP-A is preincubated with Survanta (200 μg/ml) for 15 min before addition to THP-1 cells. However, the LPS effects on TNF-α and IL-8 are inhibited by <20% and the effect on IL-1β by <50%. Third, at Survanta levels of 1 mg/ml, SP-A-induced responses are reduced by >90%, and although the inhibitory effects on LPS action increase, they still do not reach those seen with SP-A. Finally, we tested whether SP-A could induce tolerance as LPS does. Pretreatment of THP-1 cells with LPS inhibits their response to subsequent LPS treatment 24 h later, including TNF-α, IL-1β, and IL-8. Similar treatment with SP-A reduces TNF-α, but IL-1β and IL-8 are further increased by the second treatment with SP-A rather than inhibited as with LPS. Thus, whereas both SP-A and LPS stimulate cytokine production, their mechanisms differ with respect to inhibition by surfactant lipids and in ability to induce tolerance.

Lipopolysaccharide Binds Platelet Toll-Like Receptor 4 and Mediates the Activation of Phagocytes in the Reticuloendothelial System (RES): A Novel Mechanism of Host Immunity.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1093-1093
Author(s):  
John W. Semple ◽  
Rukhsana Aslam ◽  
Edwin R. Speck ◽  
John Freedman
Keyword(s):  
Flow Cytometric Analysis ◽  
Reticuloendothelial System ◽  
Tlr4 Expression ◽  
Monocytic Cell ◽  
Monocytic Cell Line ◽  
Tnf Α ◽  
Multiple Copies ◽  
Factor Α

Abstract Toll-like receptors (TLR) comprise a family of transmembrane proteins characterized by multiple copies of leucine-rich repeats in the extracellular domain and an IL-1 receptor motif in their cytoplasmic domain. The TLR family is a phylogenetically conserved mediator of innate immunity that is essential for microbial recognition and the stimulation of adaptive immune responses. Recently, our laboratory demonstrated that TLR4 expression on platelets was responsible for lipopolysaccharide (LPS)-mediated thrombocytopenia and tumour necrosis factor-α production in vivo (Aslam et al. Blood107:637, 2006). To understand the mechanism of how platelet TLR4 may mediate RES activation, platelets from wild type (WT) and TLR4 knockout mice were incubated with various concentrations of LPS in vitro, washed extensively and transfused into WT mice. Results suggest that only the WT platelets could significantly stimulate TNF-α production in vivo. In vitro flow cytometric analysis of phagocytosis by the monocytic cell line THP-1 demonstrated that platelet TLR4 could efficiently present LPS to THP-1 cells and stimulated them to engulf the LPS-coated platelets. The phagocytosis of the platelets was correlated to elevated levels of intracellular TNF-α production in the THP-1 cells. These results suggest that platelets, via TLR4 expression, can act as initial sentinels of the innate immune system by presenting bacterial products such as LPS to phagocytes of the RES.

scholarly journals Palmitate-Induced MMP-9 Expression in the Human Monocytic Cells is Mediated through the TLR4-MyD88 Dependent Mechanism

2016 ◽  
Vol 39 (3) ◽  
pp. 889-900 ◽  
Author(s):  
Sardar Sindhu ◽  
Areej Al-Roub ◽  
Merin Koshy ◽  
Reeby Thomas ◽  
Rasheed Ahmad
Keyword(s):  
Underlying Mechanism ◽  
Positive Control ◽  
Monocytic Cell ◽  
Monocytic Cell Line ◽  
Monocytic Cells ◽  
Metabolic Inflammation ◽  
Human Monocytic Cell Line ◽  
Tnf Α ◽  
Human Monocytic Cell

Background/Aims: Obese individuals are known to have increased Matrix metalloproteinase (MMP)-9 plasma levels and MMP-9 is reported to play an important role in obesity-associated adipose tissue inflammation. Since in obesity, the levels of circulatory saturated free fatty acid (FFA) palmitate (palimitic acid) are increased and modulate the expression of inflammatory mediators, the role of palmitate in the regulation of MMP-9 remains unclear. Methods: Human monocytic cell line THP-1 and primary monocytes were stimulated with palmitate and TNF-α (positive control). MMP-9 expression was assessed with real time RT-PCR and ELISA. Signaling pathways were studied by using THP-1-XBlue™ cells, THP-1-XBlue™-defMyD cells, anti-TLR4 mAb and TLR4 siRNA. Phosphorylation of NF-kB and c-Jun was analyzed by Western blotting. Results: Here, we provide the evidence that palmitate induces MMP-9 expression at both mRNA (THP-1: 6.8 ± 1.2 Fold; P = 0.01; Primary monocytes: 5.9 ± 0.7 Fold; P = 0.0003) and protein (THP1: 1116 ±14 pg/ml; P<0.001; Primary monocytes: 1426 ± 13.8; P = 0.0005) levels in human monocytic cells. Palmitate-induced MMP-9 secretion was markedly suppressed by neutralizing anti-TLR-4 antibody (P < 0.05). Furthermore, genetic silencing of TLR4 by siRNA also significantly abrogated the palmitate-induced up-regulation of MMP-9. Additionally, MyD88-/- THP-1 cells did not express MMP-9 in response to palmitate treatment. Increased NF-κB/AP-1 activity (P<0.05) was also observed in palmitate-treated THP-1 cells. Conclusion: Altogether, these results show that palmitate induces TLR4-dependent activation of MMP-9 gene expression, which requires the recruitment of MyD88 leading to activation of NF-kB/AP-1 transcription factors. Thus, our findings suggest that the palmitate-induced MMP-9 secretion might be an underlying mechanism of its increased levels in obesity and related metabolic inflammation.

Surfactant protein A enhances mycobacterial killing by rat macrophages through a nitric oxide-dependent pathway

2000 ◽  
Vol 279 (2) ◽  
pp. L216-L223 ◽  
Author(s):  
Laura F. Weikert ◽  
Joseph P. Lopez ◽  
Rasul Abdolrasulnia ◽  
Zissis C. Chroneos ◽  
Virginia L. Shepherd
Keyword(s):  
Nitric Oxide ◽  
Inflammatory Mediators ◽  
Protein A ◽  
Surfactant Protein ◽  
Nitric Oxide Production ◽  
Oxide Production ◽  
Tnf Α ◽  
Presence And Absence ◽  
Factor Α ◽  
Oxide Synthase

Surfactant-associated protein A (SP-A) is involved in surfactant homeostasis and host defense in the lung. We have previously demonstrated that SP-A specifically binds to and enhances the ingestion of bacillus Calmette-Guerin (BCG) organisms by macrophages. In the current study, we investigated the effect of SP-A on the generation of inflammatory mediators induced by BCG and the subsequent fate of ingested BCG organisms. Rat macrophages were incubated with BCG in the presence and absence of SP-A. Noningested BCG organisms were removed, and the release of tumor necrosis factor-α (TNF-α) and nitric oxide were measured at varying times. TNF-α and nitric oxide production induced by BCG were enhanced by SP-A. In addition, SP-A enhanced the BCG-induced increase in the level of inducible nitric oxide synthase protein. Addition of antibodies directed against SPR210, a specific macrophage SP-A receptor, inhibited the SP-A-enhanced mediator production. BCG in the absence of SP-A showed increased growth over a 5-day period, whereas inclusion of SP-A dramatically inhibited BCG growth. Inhibition of nitric oxide production blocked BCG killing in the presence and absence of SP-A. These results demonstrate that ingestion of SP-A-BCG complexes by rat macrophages leads to production of inflammatory mediators and increased mycobacterial killing.

Surfactant protein A regulates cytokine production in the monocytic cell line THP-1

1997 ◽  
Vol 272 (5) ◽  
pp. L996-L1004 ◽  
Author(s):  
S. G. Kremlev ◽  
T. M. Umstead ◽  
D. S. Phelps
Keyword(s):  
Cell Line ◽  
Cytokine Production ◽  
Protein A ◽  
Surfactant Protein ◽  
Surfactant Protein A ◽  
Tnf Alpha ◽  
Enzyme Linked Immunosorbent Assay ◽  
Mrna Levels ◽  
Monocytic Cell ◽  
Monocytic Cell Line

Surfactant lipids inhibit cytokine production by immune cells, and surfactant protein A (SP-A) stimulates it. By enzyme-linked immunosorbent assay and mRNA blotting, we studied proinflammatory cytokine production by the monocytic cell line THP-1. SP-A caused increases in tumor necrosis factor (TNF)-alpha within 1 h, peaking at 4 h and then declining. Interleukin (IL)-1 beta increased and stayed elevated for 24 h. SP-A stimulated IL-8 also, peaking at 4 h, rapidly declining, and peaking again at 24 h. SP-A-dependent changes were detected for IL-6, but at higher SP-A doses. mRNA levels for TNF-alpha and IL-1 beta increased in response to SP-A, peaking within 2 h. The increases in TNF-alpha mRNA and protein induced by SP-A were inhibited by surfactant lipids. For IL-1 beta and IL-8, the lipids either had no inhibitory influence or inhibited less than for TNF-alpha. This suggests that the ability of macrophages to participate in inflammatory reactions is enhanced by SP-A alone or by mixtures of lipids and SP-A containing more SP-A than in normal surfactant, as occurs in many conditions leading to inflammation.

Disparate effects of two phosphatidylcholine binding proteins, C-reactive protein and surfactant protein A, on pulmonary surfactant structure and function

2004 ◽  
Vol 287 (6) ◽  
pp. L1145-L1153 ◽  
Author(s):  
Kaushik Nag ◽  
Karina Rodriguez-Capote ◽  
Amiya Kumar Panda ◽  
Laura Frederick ◽  
Stephen A. Hearn ◽  
...  
Keyword(s):  
Binding Proteins ◽  
Amorphous Material ◽  
Protein A ◽  
Surfactant Protein ◽  
Water Soluble ◽  
Surfactant Protein A ◽  
Surface Films ◽  
Inhibitory Effects ◽  
C Reactive Protein ◽  
Reactive Protein

C-reactive protein (CRP) and surfactant protein A (SP-A) are phosphatidylcholine (PC) binding proteins that function in the innate host defense system. We examined the effects of CRP and SP-A on the surface activity of bovine lipid extract surfactant (BLES), a clinically applied modified natural surfactant. CRP inhibited BLES adsorption to form a surface-active film and the film's ability to lower surface tension (γ) to low values near 0 mN/m during surface area reduction. The inhibitory effects of CRP were reversed by phosphorylcholine, a water-soluble CRP ligand. SP-A enhanced BLES adsorption and its ability to lower γ to low values. Small amounts of SP-A blocked the inhibitory effects of CRP. Electron microscopy showed CRP has little effect on the lipid structure of BLES. SP-A altered BLES multilamellar vesicular structure by generating large, loose bilayer structures that were separated by a fuzzy amorphous material, likely SP-A. These studies indicate that although SP-A and CRP both bind PC, there is a difference in the manner in which they interact with surface films.

scholarly journals Retinoic Acid Selectively Inhibits Lipopolysaccharide Induction of Tissue Factor Gene Expression in Human Monocytes

Blood ◽  
1998 ◽  
Vol 91 (8) ◽  
pp. 2857-2865 ◽  
Author(s):  
Paul Oeth ◽  
Jin Yao ◽  
Sao-Tah Fan ◽  
Nigel Mackman
Keyword(s):  
Retinoic Acid ◽  
Tissue Factor ◽  
Human Monocytes ◽  
Monocytic Cells ◽  
All Trans Retinoic Acid ◽  
Tnf Α ◽  
Activated Monocytes ◽  
Tf Gene ◽  
Factor Α ◽  
Necrosis Factor

Expression of tissue factor (TF) by activated monocytes in several diseases leads to disseminated intravascular coagulation. Lipopolysaccharide (LPS)-induced monocyte TF expression is downregulated by the nuclear hormone all-trans retinoic acid (ATRA). In this study, we examined the mechanism by which ATRA inhibits monocyte TF expression. We show that ATRA selectively inhibited LPS induction of TF expression in human monocytes and monocytic THP-1 cells without affecting LPS induction of tumor necrosis factor-α (TNF-α) and interleukin-8 (IL-8). Inhibition of TF expression occurred at the level of transcription as determined by nuclear run-on. ATRA did not significantly alter the binding or functional activity of the transcription factors c-Fos/c-Jun and c-Rel/p65, which are required for LPS induction of the TF promoter in monocytic cells. In contrast to the ATRA inhibition of the endogenous TF gene, LPS induction of the cloned TF promoter was not inhibited by ATRA in transiently transfected THP-1 cells. Our results demonstrate that ATRA selectively inhibited LPS-induced TF gene transcription in human monocytic cells by a mechanism that does not involve repression of AP-1– or NF-κB–mediated transcription.

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