Development of Regenerative Medicine Using Reversibly Proliferating Human Bone Marrow Mesenchymal Stem Cells

人骨髓间充质干细胞(HBMSCs)具有向多种组织功能细胞分化的潜能，因此一直受到研究人员的关注。利用编码人端粒酶逆转录酶和绿色荧光蛋白基因的逆转录病毒载体SSR#197，成功地建立了永生化HMBMSC系YKNT-12。YKNT-12细胞能够无限增殖，而正常的HBMSCs在种群倍增30倍时停止增殖，表明其寿命有限。YKNT-12细胞通过在培养液中添加特定的生长因子，分别有效地分化为骨细胞、脂肪细胞和软骨细胞。为了将YKNK-12细胞与其他类型的细胞区分开来，基因操作是重要的。因此，我们研究了慢病毒载体在小鼠胚胎干细胞(ECs)中进行这种基因操作的有效性。慢病毒转导后，小鼠内皮细胞仍具有多向分化潜能。因此，慢病毒载体将成为YKNK-12细胞和人内皮细胞基因操作的有用工具之一。

Researchers have paid close attention to human bone marrow mesenchymal stem cells(HBMSCs), because HBMSCs have potentials to differentiate to various types of tissue functional cells. Using a retroviral vector SSR#197, encoding LoxP-flanked human telomerase reverse transcriptase and green fluorescence protein cDNAs, we have successfully established an immortalized HMBMSC line YKNT-12. YKNT-12 cells were able to proliferate unlimitedly, on the other hand, normal HBMSCs stopped their proliferation at population doubling 30, indicating a limited life. YKNT-12 cells efficiently differentiated to osteocytes, adipocytes, and chondrocytes by adding specific growth factors in the culture medium, respectively. To differentiate YKNK-12 cells to other-typed cells, genetic manipulation is an important. Thus, we have investigated the usefulness of a lentiviral vector for such gene manipulation in mouse embryonic stem cells(ECs). After lentiviral transduction, mouse ECs still obtained multi-differentiation potentials. Therefore, a lentiviral vector will be one of the useful tools in gene manipulation in YKNK-12 cells and human ECs.