Production of Monocyte/macrophage Colony-stimulating Factor by Preadipocyte Cell Lines Derived from Murine Marrow Stroma

Three preadipocyte cell lines that have been independently derived from bone marrow stroma (Lanotte et al, 1982) have been tested for their capacity to produce granulocyte, macrophage, and erythroid colony-stimulating factors (CSFs). All elaborated colony-stimulating material that was active upon adult mouse marrow granulocyte/macrophage colony-forming cells (M-CFC) but not foetal liver GM-CFC. The major activity was characterised as a monocyte-macrophage colony-stimulating factor (M-CSF), and the pattern of colony stimulation was similar to that seen after addition of highly purified L-cell CSF. Furthermore, the stimulating activity was specifically neutralised by rabbit anti-L cell CSF antibodies. No evidence was found for stimulation of multipotential or erythroid colony-forming cells, only few granulocytic colonies were detected, and the stimulating activity had no mouse strain restriction. All cell lines produced large quantities of M-CSF; however, the production was found to be modulated during the adipogenesis process. A peak in M-CSF production corresponded to the period of growth arrest after confluence of the stromal cells was reached and when adipocyte maturation was at an early stage. A marked depression in M-CSF secretion was associated with the final steps of adipocyte maturation.