Yu J M, Emmons R V, Hanazono Y, Sellers S, Young N S, Dunbar C E
Hematology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Exp Hematol. 1999 May;27(5):895-903. doi: 10.1016/s0301-472x(99)00009-0.
Several lines of evidence suggest that overexpression of interferon gamma (IFN-gamma) in the marrow microenvironment may play a role in the pathogenesis of marrow suppression in aplastic anemia. We previously showed that overexpression of IFN-gamma by marrow stromal cells inhibits human long-term culture initiating cell activity assayed in vitro to a much greater degree than the addition of soluble IFN-gamma. The effect of IFN-gamma on true repopulating stem cells assayed in vivo has not been studied previously. We compared the effect of co-culture of murine marrow cells in the presence of stromal cells transduced with a retroviral vector expressing murine IFN-gamma vs stromal cells transduced with a control neo vector. Using a murine congenic competitive repopulation assay, there was significantly less long-term repopulating stem cell activity remaining after culture on mIFN-gamma-expressing stroma as compared to control stroma. We also investigated the effect of directly transducing murine bone marrow cells with the mIFN-gamma or control vector. Marrow cells transduced with either vector were transplanted into W/Wv recipient mice. The percentage of vector-containing cells in the mIFN-gamma mice was significantly lower than in the control mice, suggesting that mIFN-gamma-transduced primitive cells may not have survived culture, or that mIFN-gamma directly decreases gene transfer into repopulating cells. Despite no significant differences in white or red blood cells in the mice transplanted with the mIFN-gamma-transduced cells, the number of bone marrow colony-forming unit-C 16 weeks after transplantation was significantly lower in the IFN-gamma group. These data indicate that ectopic or overexpression of mIFN-gamma, especially by marrow microenvironmental elements, may have a marked effect on primitive hematopoiesis as assayed in vivo.
多条证据表明，骨髓微环境中γ干扰素（IFN-γ）的过表达可能在再生障碍性贫血骨髓抑制的发病机制中起作用。我们之前发现，骨髓基质细胞过表达IFN-γ对体外测定的人类长期培养起始细胞活性的抑制作用，比添加可溶性IFN-γ的抑制作用大得多。此前尚未研究过IFN-γ对体内测定的真正重建造血干细胞的影响。我们比较了在表达鼠IFN-γ的逆转录病毒载体转导的基质细胞存在下，与对照新霉素载体转导的基质细胞共同培养鼠骨髓细胞的效果。使用鼠同源竞争重建造血分析方法，与对照基质相比，在表达mIFN-γ的基质上培养后，剩余的长期重建造血干细胞活性显著降低。我们还研究了用mIFN-γ或对照载体直接转导鼠骨髓细胞的效果。用任一载体转导的骨髓细胞被移植到W/Wv受体小鼠体内。mIFN-γ小鼠中含载体细胞的百分比显著低于对照小鼠，这表明经mIFN-γ转导的原始细胞可能在培养后未存活，或者mIFN-γ直接降低了向重建造血细胞的基因转移。尽管移植了经mIFN-γ转导细胞的小鼠在白细胞或红细胞方面没有显著差异，但移植后16周，IFN-γ组的骨髓集落形成单位-C数量显著更低。这些数据表明，mIFN-γ的异位表达或过表达，尤其是骨髓微环境成分的过表达，可能对体内测定的原始造血有显著影响。
