Alterations of Toll-like Receptor 4 Expression on Peripheral Blood Monocytes During the Early Stage of Human Acute Pancreatitis

Bacterial lipopolysaccharide (LPS) is a powerful activator of the innate immune system. Exposure to LPS induces an inflammatory reaction in the lung mediated primarily by human blood monocytes and alveolar macrophages, which release an array of inflammatory chemokines and cytokines including IL-8, TNF-α, IL-1β, and IL-6. The signaling mechanisms utilized by LPS to stimulate the release of cytokines and chemokines are still incompletely understood. Pretreatment with the protein tyrosine kinase-specific inhibitors genistein and herbimycin A effectively blocked LPS-induced NF-κB activation as well as IL-8 gene expression in human peripheral blood monocytes. However, when genistein was added 2 min after the addition of LPS, no inhibition was observed. Utilizing a coimmunoprecipitation assay, we further showed that LPS-stimulated tyrosine phosphorylation of Toll-like receptor 4 (TLR4) may be involved in downstream signaling events induced by LPS. These findings provide evidence that LPS-induced NF-κB activation and IL-8 gene expression use a signaling pathway requiring protein tyrosine kinase and that such regulation may occur through tyrosine phosphorylation of TLR4.

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Enhanced expression of Toll-like receptor 2 in lesional tissues and peripheral blood monocytes of patients with oral lichen planus

The Journal of Dermatology ◽

10.1111/j.1346-8138.2010.00956.x ◽

2010 ◽

Vol 38 (4) ◽

pp. 335-344 ◽

Cited By ~ 24

Author(s):

Seiji OHNO ◽

Yoshihisa TATEISHI ◽

Yukihiro TATEMOTO ◽

Keiko MORISHITA ◽

Eri SASABE ◽

...

Keyword(s):

Lichen Planus ◽

Peripheral Blood ◽

Oral Lichen Planus ◽

Toll Like Receptor ◽

Blood Monocytes ◽

Peripheral Blood Monocytes ◽

Enhanced Expression ◽

Toll Like Receptor 2 ◽

Oral Lichen

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Characterization of Monocyte-Associated Factor V

Thrombosis and Haemostasis ◽

10.1055/s-0038-1649565 ◽

1993 ◽

Vol 70 (02) ◽

pp. 273-280 ◽

Cited By ~ 5

Author(s):

Janos Kappelmayer ◽

Satya P Kunapuli ◽

Edward G Wyshock ◽

Robert W Colman

Keyword(s):

Monoclonal Antibody ◽

Light Chain ◽

Peripheral Blood ◽

De Novo ◽

Factor V ◽

Blood Monocytes ◽

De Novo Synthesis ◽

Hep G2 ◽

Hep G2 Cells ◽

Peripheral Blood Monocytes

SummaryWe demonstrate that in addition to possessing binding sites for intact factor V (FV), unstimulated peripheral blood monocytes also express activated factor V (FVa) on their surfaces. FVa was identified on the monocyte surface by monoclonal antibody B38 recognizing FVa light chain and by human oligoclonal antibodies H1 (to FVa light chain) and H2 (to FVa heavy chain) using immunofluorescence microscopy and flow cytometry. On Western blots, partially cleaved FV could be identified as a 220 kDa band in lysates of monocytes. In addition to surface expression of FVa, monocytes also contain intracellular FV as detected only after permeabilization by Triton X-100 by monoclonal antibody B10 directed specifically to the Cl domain not present in FVa. We sought to determine whether the presence of FV in peripheral blood monocytes is a result of de novo synthesis.Using in situ hybridization, no FV mRNA could be detected in monocytes, while in parallel control studies, factor V mRNA was detectable in Hep G2 cells and CD18 mRNA in monocytes. In addition, using reverse transcriptase and the polymerase chain reaction, no FV mRNA was detected in mononuclear cells or in U937 cells, but mRNA for factor V was present in Hep G2 cells using the same techniques. These data suggest that FV is present in human monocytes, presumably acquired by binding of plasma FV, and that the presence of this critical coagulation factor is not due to de novo synthesis.

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