Apolipoprotein A-I Stimulates Cell Proliferation in Bone Marrow Cell Culture

Culturing of bone marrow cells in serum-free RPMI-1640 medium led to a decrease in the rate of DNA biosynthesis. Addition of HDL or their main protein component apolipoprotein A-I to the culture medium dose-dependently increased the rate of [H-3]-thymidine incorporation into DNA. The maximum stimulation was achieved at HDL concentration of 80 mu g/ml and apolipoprotein A-I concentration of 20 mu g/ml. To identify the target-cells of apolipoprotein A-I, we used thymidine analogue 5-ethynyl-2'-deoxyuridine (EdU) that incorporates into cell DNA at the stage of replicative DNA synthesis (S phase) and can be detected by fluorescence microscopy. In bone marrow cell culture, apolipoprotein A-I stimulates the proliferation of monocyte (monoblasts, promonocytes) and granulocyte (myeloblasts, promyelocytes) progenitor cells, as well as bone marrow stromal cells.