Related Experiment Videos
Indirect induction of differentiation in myeloid leukemic cells by lipid A
Abstract:
Normal myeloid and MGI(+)D(+) clones of myeloid leukemic cells can be induced for Fc and complement component 3 rosettes, lysozme, and mature macrophages and granulocytes by a protein with macrophage- and granulocyte-inducing (MGI) activity, whereas MGI(+)D(-) clones can be induced by this protein for rosettes and lysozme but not mature cells. Lipopolysaccharides (LPS) from different bacteria induced the appearance of rosettes, lysozyme, and macrophages in some MGI(+)D(+) clones but did not induce any of these changes in MGI(+)D(-) clones. Lipid A gave the same results as LPS. Incubation of MGI(+)D(+) cells with LPS also induced an MGI activity detectable in the culture medium. This activity behaved like MGI in inducing (i) rosettes, lysozyme, and mature cells in MGI(+)D(+) leukemic cells including a clone resistant to LPS, (ii) rosettes and lysozyme in MGI(+)D(-) leukemic cells, and (iii) differentiation of normal myeloid cells to mature macrophages and granulocytes. This activity was induced in MGI(+)D(+) cells by LPS before the induction of rosettes or lysozyme. The results indicate that the lipid A portion of LPS indirectly induces differentiation of MGI(+)D(+) myeloid leukemic cells by inducing MGI protein. It is suggested that induction of specific regulatory proteins may be a more general mechanism for the induction of differentiation by surface-acting compounds.
Insights
Lipopolysaccharides (LPS) induce myeloid leukemic cell differentiation by stimulating macrophage- and granulocyte-inducing (MGI) protein production. This mechanism, involving lipid A, suggests a broader role for regulatory proteins in cell differentiation.
Area of Science:
- Hematology
- Cell Biology
- Immunology
Background:
- Myeloid leukemic cells exhibit varying differentiation potentials.
- Macrophage- and granulocyte-inducing (MGI) activity promotes myeloid cell maturation.
- Lipopolysaccharides (LPS) are bacterial components known to interact with myeloid cells.
Purpose of the Study:
- To investigate the mechanism by which LPS induces differentiation in myeloid leukemic cells.
- To determine the role of MGI protein in LPS-mediated myeloid cell differentiation.
- To explore the potential of surface-acting compounds in inducing cell differentiation.
Main Methods:
- Treatment of normal myeloid and leukemic cell clones (MGI(+)D(+), MGI(+)D(-)) with MGI protein and LPS.
- Assays for Fc and complement component 3 rosettes, lysozyme activity, and mature cell formation.
- Detection and characterization of MGI activity in culture medium.
Main Results:
- MGI protein induced differentiation in MGI(+)D(+) and MGI(+)D(-) cells, with varying degrees of maturation.
- LPS and its lipid A component induced differentiation markers in MGI(+)D(+) cells but not MGI(+)D(-) cells.
- LPS treatment of MGI(+)D(+) cells induced MGI activity in the medium, preceding differentiation markers.
Conclusions:
- The lipid A portion of LPS indirectly induces myeloid leukemic cell differentiation by stimulating MGI protein production.
- Induction of MGI protein is a key intermediate step in LPS-mediated myeloid differentiation.
- Induction of specific regulatory proteins may represent a general mechanism for surface-acting compound-induced differentiation.