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Tissue factor expression in human monocytic cell lines
1Department of Clinical Chemistry, University Hospital, Uppsala, Sweden.
Thrombosis Research
|November 15, 1997
Summary
Monocytes control blood clotting via tissue factor (TF). Researchers studied TF expression in two cell lines, U-937 and Mono Mac 6, revealing distinct responses to stimuli like PMA, LPS, and TNF.
Area of Science:
- Hematology
- Cell Biology
- Immunology
Background:
- Tissue factor (TF) initiates the coagulation cascade.
- Monocytes are the primary blood cells expressing TF.
- Regulating TF expression in monocytes is crucial for hemostasis.
Purpose of the Study:
- To investigate TF expression in human monocytic cell lines at different differentiation stages.
- To compare basal and induced TF expression in U-937 and Mono Mac 6 cell lines.
- To identify differential responses to TF-modulating agents.
Main Methods:
- Utilized U-937 (monoblastic) and Mono Mac 6 (mature monocyte-like) human cell lines.
- Assessed TF surface protein and mRNA levels using immunofluorescence and quantitative reverse transcriptase polymerase chain reaction.
- Examined the effects of phorbol-12-myristate-13-acetate (PMA), lipopolysaccharide (LPS), and tumor necrosis factor (TNF) on TF expression.
Main Results:
- U-937 cells exhibited constitutive TF surface protein expression with low mRNA levels, potently enhanced by PMA.
- LPS and TNF did not affect TF expression in U-937 cells.
- Mono Mac 6 cells showed lower basal TF mRNA and surface antigen levels but demonstrated induced TF expression upon stimulation with LPS and TNF.
Conclusions:
- Significant differences exist in basal and induced TF expression patterns between U-937 and Mono Mac 6 cell lines.
- These findings highlight distinct regulatory mechanisms of TF expression during monocytic differentiation.
- The differential responses underscore the importance of cell context in TF-mediated coagulation initiation.