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Effects of lipopolysaccharide on a macrophage-like cell line (HS-P) from a rat histiocytic sarcoma
1Department of Veterinary Pathology, Graduate School of Agriculture and Biological Science, Osaka Prefecture University, Gakuencho 1-1, Sakai, Osaka, 599-8531, Japan.
Abstract:
Lipopolysaccharide (LPS) is a major modulator of macrophage functions. To characterize a newly established rat histiocytic sarcoma-derived cell line (HS-P), immunophenotypic changes and cellular growth responses of HS-P cells exposed to LPS were investigated and compared with those of MT-9 cells isolated from a rat malignant fibrous histiocytoma. MT-9 cells have somewhat histiocytic features, because occasional cells react to rat macrophage-specific antibodies. Addition of LPS to cultured HS-P cells increased the numbers of cells immunopositive to ED1 (rat macrophage-specific antibody) and ED2 (rat histiocyte-specific antibody) and stimulated the phagocytosis of latex beads, whereas LPS-treated MT-9 cells did not show such immunophenotypic changes. LPS-treated HS-P cells showed enhanced immunolabelling of alpha-smooth muscle actin, suggesting a possible modulation of macrophages towards myofibroblastic cells. To evaluate cellular growth after the addition of LPS or fetal bovine serum, DNA synthesis was examined by measuring tritiated thymidine incorporation, and the mRNA expression of c- jun and c- myc (immediate early genes in the cell cycle) was examined by Northern blot analysis. In HS-P cells, the addition of serum greatly increased DNA synthesis and induced high expression of c- jun and c- myc; in contrast, LPS markedly depressed DNA synthesis and reduced the expression of c- jun and c- myc. HS-P cells were more sensitive than MT-9 cells to the growth-promoting effect of serum and the growth-inhibiting effect of LPS. The study demonstrated that HS-P cells are highly LPS-responsive, indicating that they would be useful for studies of macrophage functions.
Insights
Newly established rat histiocytic sarcoma cells (HS-P) show significant responses to lipopolysaccharide (LPS), including altered macrophage markers and inhibited DNA synthesis. These LPS-responsive HS-P cells are valuable for macrophage function research.
Area of Science:
- Immunology
- Cell Biology
- Oncology
Background:
- Lipopolysaccharide (LPS) is a key regulator of macrophage behavior.
- Characterizing novel cell lines is crucial for understanding macrophage functions.
- Rat histiocytic sarcoma-derived cell line (HS-P) and MT-9 cells were utilized for comparative analysis.
Purpose of the Study:
- To investigate the immunophenotypic changes and cellular growth responses of HS-P cells upon LPS exposure.
- To compare the LPS response of HS-P cells with MT-9 cells, derived from a rat malignant fibrous histiocytoma.
- To assess the utility of HS-P cells for studying macrophage functions.
Main Methods:
- Immunophenotyping using ED1 and ED2 antibodies.
- Phagocytosis assay with latex beads.
- DNA synthesis measurement via tritiated thymidine incorporation.
- mRNA expression analysis of c-jun and c-myc using Northern blot.
Main Results:
- LPS treatment increased ED1/ED2 immunopositivity and phagocytosis in HS-P cells, but not in MT-9 cells.
- LPS-treated HS-P cells exhibited enhanced alpha-smooth muscle actin expression.
- HS-P cells showed reduced DNA synthesis and c-jun/c-myc expression in response to LPS, unlike serum stimulation.
- HS-P cells demonstrated greater sensitivity to both serum's growth promotion and LPS's growth inhibition compared to MT-9 cells.
Conclusions:
- HS-P cells are highly responsive to LPS, exhibiting distinct immunophenotypic and growth modulations.
- The observed responses suggest potential macrophage modulation towards myofibroblastic cells.
- HS-P cells serve as a valuable model for investigating macrophage functions and LPS interactions.