Clohisy D R, Bar-Shavit Z, Chappel J C, Teitelbaum S L
Department of Pathology and Laboratory Medicine, Jewish Hospital at Washington University Medical Center, St. Louis, Missouri 63110.
J Biol Chem. 1987 Nov 25;262(33):15922-9.
1,25-Dihydroxyvitamin D3 (1,25-(OH)2D3), the biologically active form of vitamin D3, has been shown to inhibit proliferation and promote monocytic differentiation of leukemic cell lines. In the present communication, we extend these observations to normal bone marrow macrophage precursors, and 1) identify the stage of monocytic maturation wherein the steroid exerts its antiproliferative effect, and 2) demonstrate that 1,25-(OH)2D3 promotes bone marrow macrophage differentiation as manifest by specific up-regulation of the lineage-specific membrane protein, the mannose-fucose receptor. In these experiments, the 1,25-(OH)2D3-mediated inhibitory effect on colony formation was shown to be independent of attendant levels of colony stimulating factor-1 and targeted through the adherent bone marrow macrophage precursor. Examination of this steroid-sensitive adherent precursor population demonstrates that its specific binding of 125I-mannose bovine serum albumin spontaneously and progressively increases with time in culture. Whereas adherent bone marrow macrophages cultured for 2 days express 3 X 10(4) mannose receptors/cell, the number of binding sites increases to 7 X 10(4)/cell by day 4. When bone marrow macrophage precursors are exposed to 1,25-(OH)2D3, an additional stepwise enhancement of 125I-mannose bovine serum albumin obtains with time. Four days of culture with the steroid results in 1.6 X 10(5) mannose receptors/cell, a 100% increase as compared to control cells. Neither duration of culture nor exposure to 1,25-(OH)2D3 alters the KD of 125I-mannose bovine serum albumin which approximates 3-5 X 10(-9) ml-1. Finally, the "specificity" of vitamin D-mediated up-regulation of the mannose receptor was established by demonstrating that the steroid does not alter binding of 125I-alpha-thrombin by bone marrow-derived macrophage precursors.
1,25 - 二羟基维生素D3（1,25-(OH)2D3）是维生素D3的生物活性形式，已被证明可抑制白血病细胞系的增殖并促进其单核细胞分化。在本报告中，我们将这些观察结果扩展至正常骨髓巨噬细胞前体，并：1）确定单核细胞成熟阶段中该类固醇发挥其抗增殖作用的阶段，以及2）证明1,25-(OH)2D3促进骨髓巨噬细胞分化，表现为谱系特异性膜蛋白——甘露糖 - 岩藻糖受体的特异性上调。在这些实验中，1,25-(OH)2D3对集落形成的介导抑制作用被证明独立于集落刺激因子 - 1的伴随水平，并通过贴壁骨髓巨噬细胞前体起作用。对这种类固醇敏感的贴壁前体细胞群的检查表明，其对125I - 甘露糖牛血清白蛋白的特异性结合在培养过程中随时间自发且逐渐增加。培养2天的贴壁骨髓巨噬细胞每细胞表达3×10⁴个甘露糖受体，到第4天结合位点数量增加到7×10⁴/细胞。当骨髓巨噬细胞前体暴露于1,25-(OH)2D3时，随着时间的推移，125I - 甘露糖牛血清白蛋白会进一步逐步增强结合。用该类固醇培养4天导致每细胞有1.6×10⁵个甘露糖受体，与对照细胞相比增加了100%。培养持续时间和暴露于1,25-(OH)2D3均未改变125I - 甘露糖牛血清白蛋白的解离常数，其近似为3 - 5×10⁻⁹ml⁻¹。最后，通过证明该类固醇不会改变骨髓来源的巨噬细胞前体对125I - α - 凝血酶的结合，确定了维生素D介导的甘露糖受体上调的“特异性”。
