Hagiwara T, Kodama I, Horie K, Kato T, Miyazaki H
Pharmaceutical Research Laboratory, Kirin Brewery Co., Ltd., Takasaki, Gunma, Japan.
Exp Hematol. 1998 Mar;26(3):228-35.
We evaluated the effects of human thrombopoietin (TPO) alone, or in combination with other several hematopoietic factors, on megakaryocyte colony growth from human umbilical cord blood CD34+ cells in serum-depleted agar cultures. The addition of TPO alone had a concentration-dependent effect on the number of pure megakaryocyte colonies and of megakaryocytes per colony (colony size). The maximally stimulating concentration of TPO generated a greater number of megakaryocyte colonies and larger megakaryocyte colony size compared with the stimulation observed with an optimal concentration of human interleukin-3 (IL-3) or stem cell factor (SCF). At the high concentration of TPO that yielded the maximum colony numbers, a substantial proportion of megakaryocyte colonies contained 100 or more cells per colony. The combination of TPO plus SCF resulted in a synergistic enhancement of both the number and size of megakaryocyte colonies. Among the combinations of TPO plus other cytokines tested, IL-3 plus TPO had a modest effect on megakaryocyte colony numbers. The generation of megakaryocyte colonies from subpopulations of CD34+ cells was further examined. The addition of TPO alone induced a greater number of megakaryocyte colonies from CD34+CD41+ cells compared with CD34+CD41- cells, and TPO plus IL-3 exerted a synergistic effect on the number of megakaryocyte colonies only from CD34+CD41- cells. In contrast to the effects on colony numbers, TPO induced larger megakaryocyte colony sizes from CD34+CD41- cells, compared with CD34+CD41+ cells. In the case of HLA-DR expression, TPO and IL-3, administered singly or in combination, induced similar megakaryocyte colony numbers and sizes from CD34+DR+ and CD34+DR- subpopulations. Ploidy analysis revealed that the majority of megakaryocytes generated from cord blood CD34+ cells in serum-free liquid cultures containing TPO displayed 2N and 4N values, suggesting that they were immature. These results indicate that, compared with IL-3 and SCF, TPO has more potent proliferative effect on human cord blood megakaryocyte progenitors, leading to greater numbers of megakaryocyte progenitors triggered for both growth and cell division, and synergizes with SCF to enhance megakaryocyte colony growth.
我们评估了单独使用人血小板生成素（TPO）或与其他几种造血因子联合使用，对血清饥饿琼脂培养中来自人脐带血CD34+细胞的巨核细胞集落生长的影响。单独添加TPO对纯巨核细胞集落的数量以及每个集落中的巨核细胞数量（集落大小）具有浓度依赖性作用。与用人白细胞介素-3（IL-3）或干细胞因子（SCF）的最佳浓度所观察到的刺激相比，TPO的最大刺激浓度产生了更多的巨核细胞集落和更大的巨核细胞集落大小。在产生最大集落数的高浓度TPO下，相当一部分巨核细胞集落每个集落含有100个或更多细胞。TPO加SCF的组合导致巨核细胞集落的数量和大小都协同增加。在测试的TPO加其他细胞因子的组合中，IL-3加TPO对巨核细胞集落数量有适度影响。进一步研究了从CD34+细胞亚群产生巨核细胞集落的情况。与CD34+CD41-细胞相比，单独添加TPO从CD34+CD41+细胞诱导产生更多的巨核细胞集落，并且TPO加IL-3仅对来自CD34+CD41-细胞的巨核细胞集落数量发挥协同作用。与对集落数量的影响相反，与CD34+CD41+细胞相比，TPO从CD34+CD41-细胞诱导产生更大的巨核细胞集落大小。就HLA-DR表达而言，单独或联合给予TPO和IL-3，从CD34+DR+和CD34+DR-亚群诱导产生相似数量和大小的巨核细胞集落。倍性分析显示，在含有TPO的无血清液体培养中，从脐带血CD34+细胞产生的大多数巨核细胞显示2N和4N值，表明它们是不成熟的。这些结果表明，与IL-3和SCF相比，TPO对人脐带血巨核细胞祖细胞具有更强的增殖作用，导致更多的巨核细胞祖细胞被触发进行生长和细胞分裂，并与SCF协同增强巨核细胞集落生长。
