A monocyte-derived growth factor (MDGF) that stimulates proliferation of fibroblast and smooth muscle cells was purified from mitogen-stimulated human peripheral blood lymphocyte conditioned medium by using anion-exchange, Bio-Sil TSK-250 HPLC gel-permeation chromatography, and NaDodSO4/PAGE. Purified MDGF exhibited acidic charge characteristics (pI 5.0) and migrated with an apparent M(r) of 40,000 ± 2000 in molecular sizing HPLC colums. Elution from NaDodSO4/polyacrylamide gels showed that the growth-promoting activity was associated with three or four protein bands. The highest molecular weight species representing the most intense silver-stained band corresponded to 42,000; the lowest molecular weight species was 33,000. MDGF activity was stable to treatment with acid (pH 2.0) or base (pH 10.0) and heating (100°C, 5 min) but was inactivated upon reduction with 2-mercaptoethanol. The acidic MDGF did not effectively compete with platelet-derived growth factor (PDGF) for receptor binding and was not inhibited by PDGF antibodies. Previous studies have suggested that fibroblast growth-stimulating activity of macrophages is largely due to their secretion of interleukin 1 and a PDGF-like molecule. Our purification and biochemical characterization studies reveal the occurrence of multiple forms of fibroblast growth-stimulating activity in human monocyte conditioned medium. The MDGF activity characterized here appears to be structurally and functionally distinct from the previously described fibroblast growth-promoting activities including interleukin 1, basic fibroblast growth factor, and PDGF.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - Jan 1 1988|
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