A study for the mechanism of negative hematopoietic regulation by bone marrow microenvironment.

正常造血的特征是造血干细胞与构成产生血细胞的微环境部分的细胞和分子之间的平衡相互作用。这反过来又表明，这种微环境中某些元素的变化可能会导致血细胞的异常产生。骨髓基质细胞是间充质细胞的异质集合，在骨髓培养中以贴壁层的形式生长，是微环境的重要组成部分。1)将含有SV40早期基因的重组SV40-腺病毒载体导入骨髓增生异常综合征(MDS)难治性贫血(RA)患者，建立了克隆的基质细胞系LS801。LS801诱导共培养体系中的造血细胞发生凋亡改变。当造血细胞与LS801共培养但通过0.45μm Mi…保持分离时LS801诱导造血细胞凋亡的作用受到抑制。这些结果表明，LS801通过产生扩散因子(S)和通过直接的细胞相互作用诱导造血细胞的凋亡改变。2)从LS801的培养上清液中分离到一种超分子低聚物--环状聚乳酸。这种寡聚体被发现能诱导造血细胞的凋亡改变。其作用机制尚不清楚，但该低聚体处理后的造血细胞糖酵解酶活性受到抑制。3)在部分骨髓增生异常综合征患者的基质细胞中，通过产生肿瘤坏死因子α诱导造血细胞发生凋亡改变。我们发现，维生素K2抑制了这些基质细胞产生肿瘤坏死因子α，并刺激了这些基质细胞的培养，这些结果表明基质细胞对造血细胞的增殖和分化既有刺激作用，也有抑制作用。较少

Normal hematopoiesis is characterized by a balanced interplay between hematopoietic stem cells and the cells and molecules that form the portion of the microenvironment in which blood cell production takes place. This in turn suggests that alterations in some of the elements of this microenvironment may result in abnormal production of blood cells. Bone marrow stromal cells, a heterogenous collection of mesenchymal cells that grow as an adherent layer in bone marrow culture, are an essential component of the microenvironment. In this study, the hematopoietic regulatory mechanisms of stromal cell were investigated in vitro.1) A cloned stromal cell line (LS801) was established from an myelodysplastic syndrome (MDS) refractory anemia (RA) patient by introducing recombinant SV40-adenovirus vector containing the SV40 early gene. LS801 induced an apoptotic change in hematopoietic cells in a coculture system. When hematopoietic cells were cocultured but kept separate from LS801 by a 0.45μm Mi … More llipore membrane to prevent their attachment, the action of LS801 in inducing apoptosis of hematopoietic cells was inhibited. These findings suggest that LS801 induced an apoptotic change of hematopoietic cells by producing diffusible factor(s) and via direct cellular interactions.2) A supramolecular oligomer, cyclic polylactate was isolated from the culture medium of LS801. This oligomer was found to induce apoptotic change in hematopoietic cells. The mechanism responsible for this action remains unclear, however, the activities of glycolytic enzymes of hematopoietic cells treated with this oligomer were suppressed.3) In some stromal cells originated from MDS patients induced apoptotic change of hematopoietic cells by producing TNFα. We found that the treatment with vitamin K2 suppressed the production of TNFα from these stromal cells, and hematopoiesis in culture with these stromal cells were stimulated.All these findings suggest that stromal cells possess both stimulatory and inhibitory action for the proliferation and differentiation of hematopoietic cells. Less