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Polyanion induced preferential multinucleation in macrophages at a low level of TNF-alpha secretion
M Okazaki1, K Akimoto, K Sorimachi
1Department of Surgery, Dokkyo University School of Medicine, Tochigi, Japan.
Abstract:
When rat bone marrow macrophages were incubated with acetyl lignin (EP3) in the presence of a 10% solution of fetal bovine serum, the macrophages secreted tumor necrosis factor (TNF-alpha) in a dose-dependent manner. This was followed by macrophage multinucleation. EP3 was found to have a significant effect on TNF-alpha secretion at a minimum dose of 5 micrograms/ml and produced no significant further increase at levels above 50 micrograms/ml, while multinucleation was most active at 10 micrograms/ml. However, multinucleation did not occur at higher concentrations of EP3 (50 micrograms/ml and 100 micrograms/ml). Secretion of TNF-alpha was significantly reduced in the absence of fetal bovine serum, whereas multinucleation was very active, starting after 6 h of incubation. At concentrations of 100 micrograms/ml, sulfonyl lignin (LS) and dextran sulfate (DS) only induced low levels of TNF-alpha secretion from macrophages, but induced active multinucleation. The multinucleation induced by addition of LS or DS was inhibited by further addition of EP3. Thus, macrophage multinucleation was most active when a low level of TNF-alpha was secreted from the macrophages.
Insights
Acetyl lignin (EP3) triggers tumor necrosis factor-alpha (TNF-alpha) secretion and macrophage multinucleation. Optimal multinucleation occurred with low TNF-alpha levels, suggesting a complex regulatory relationship.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Macrophages are key immune cells involved in inflammation and tissue repair.
- Tumor necrosis factor-alpha (TNF-alpha) is a critical cytokine in immune responses.
- Lignin derivatives are being investigated for their biological activities.
Purpose of the Study:
- To investigate the effect of acetyl lignin (EP3) on rat bone marrow macrophage function.
- To determine the relationship between EP3-induced TNF-alpha secretion and macrophage multinucleation.
Main Methods:
- Incubation of rat bone marrow macrophages with varying concentrations of acetyl lignin (EP3).
- Measurement of TNF-alpha secretion using standard assays.
- Microscopic observation of macrophage morphology, specifically multinucleation.
- Experiments conducted with and without fetal bovine serum.
Main Results:
- EP3 induced a dose-dependent secretion of TNF-alpha, with significant effects from 5 µg/ml to 50 µg/ml.
- Macrophage multinucleation was most active at 10 µg/ml EP3 but inhibited at higher concentrations (50-100 µg/ml).
- Absence of fetal bovine serum reduced TNF-alpha but enhanced multinucleation.
- Sulfonyl lignin (LS) and dextran sulfate (DS) induced multinucleation with low TNF-alpha secretion, which was inhibited by EP3.
Conclusions:
- Acetyl lignin modulates macrophage responses, influencing both TNF-alpha secretion and multinucleation.
- Macrophage multinucleation is inversely correlated with high levels of TNF-alpha secretion.
- EP3's inhibitory effect on LS/DS-induced multinucleation suggests complex signaling pathways.