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Laminin promotes proliferation of bone marrow-derived macrophages and macrophage cell lines
Abstract:
We examined the effect of laminin on DNA synthesis or cell growth of bone marrow-derived macrophages (BMM) and five macrophage cell lines including two factor-dependent macrophage cell lines (BDM-1 and BDM-1W3) and three factor-independent ones (BAM3, J774.1, and P388D1). Laminin stimulated the M-CSF-dependent proliferation of BMM and BDM-1 cells in a dose-dependent manner, but it had no effect on the proliferation of BDM-1W3 cells. This stimulatory effect was modified by increasing the concentration of fetal calf serum in the culture medium. Laminin also stimulated the proliferation of BAM3 and J774.1 cells, whereas it could not stimulate that of P388D1 cells. Taken together, these results suggest that the differences in the response of these macrophage cell lines to the presence of laminin may be derived from the difference in the state of maturation of these cells. Although laminin acted as a potent mitogenic factor when it was added to the culture medium, the stimulation was two- to threefold lower when dishes were coated with equivalent amounts of laminin. When BDM-1 cells were cultured with laminin, they underwent drastic morphological changes. A monoclonal antibody that recognizes the integrin alpha 6 subunit only partially inhibited the mitogenic effect of laminin. The results in this report suggest that laminin may participate in the regulation of macrophage populations in vivo.
Insights
Laminin promotes macrophage proliferation, particularly in less mature cells, influencing their growth and morphology. Its effects vary based on cell type and culture conditions, suggesting a role in regulating macrophage populations.
Area of Science:
- Cell Biology
- Immunology
- Biochemistry
Background:
- Macrophages are crucial immune cells involved in various physiological processes.
- Laminin, a key component of basement membranes, plays roles in cell adhesion, migration, and differentiation.
- Understanding extracellular matrix influences on macrophage behavior is vital for immunology and regenerative medicine.
Purpose of the Study:
- To investigate the impact of laminin on the DNA synthesis and proliferation of various macrophage populations.
- To explore how laminin's effects differ across macrophage cell lines with varying maturation states.
- To elucidate the potential role of laminin in regulating macrophage populations in vivo.
Main Methods:
- Cultured bone marrow-derived macrophages (BMM) and five macrophage cell lines (BDM-1, BDM-1W3, BAM3, J774.1, P388D1).
- Assessed cell proliferation and DNA synthesis in response to varying laminin concentrations and culture conditions (e.g., fetal calf serum).
- Examined morphological changes and used a monoclonal antibody against integrin alpha 6 to probe underlying mechanisms.
Main Results:
- Laminin dose-dependently stimulated M-CSF-dependent proliferation of BMM and BDM-1 cells.
- Laminin also enhanced proliferation in BAM3 and J774.1 cells but not in BDM-1W3 or P388D1 cells.
- Stimulatory effects were modulated by fetal calf serum; laminin in culture medium was more potent than when coated on dishes. Morphological changes and partial inhibition by anti-integrin alpha 6 antibody were observed.
Conclusions:
- Differential responses suggest laminin's effect on macrophages is linked to their maturation state.
- Laminin acts as a mitogenic factor for certain macrophage types.
- These findings indicate laminin may play a significant role in the in vivo regulation of macrophage populations.