Nakamura Sou, Sugimoto Naoshi, Eto Koji
Department of Clinical Application, Center for iPS Cell Research and Application, Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan.
Department of Regenerative Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba-shi, Chiba, 260-8677, Japan.
Inflamm Regen. 2020 Dec 1;40(1):30. doi: 10.1186/s41232-020-00139-2.
Platelet products are used in treatments for thrombocytopenia caused by hematopoietic diseases, chemotherapy, massive hemorrhages, extracorporeal circulation, and others. Their manufacturing depends on volunteers who donate blood. However, it is becoming increasingly necessary to reinforce this blood donation system with other blood sources due to the increase in demand and shortage of supply accompanying aging societies. In addition, blood-borne infections and alloimmune platelet transfusion refractoriness are not completely resolved. Since human induced pluripotent stem cell (iPSC)-platelet products can be supplied independently from the donor, it is expected to complement current platelet products. One big hurdle with iPSC-based systems is the production of 10 units, which is equivalent to 200 billion platelets. To overcome this issue, we established immortalized megakaryocyte cell lines (imMKCLs) by introducing three transgenes, c-MYC, BMI1, and BCL-XL, sequentially into hematopoietic and megakaryocytic progenitor stage cells derived from iPSCs. The three transgenes are regulated in a Tet-ON manner, enabling the addition and depletion of doxycycline to expand and maturate the imMKCLs, respectively. In addition, we succeeded in discovering drug combinations that enable feeder-free culture conditions in the imMKCL cultivation. Furthermore, we discovered the importance of turbulence in thrombopoiesis through live bone marrow imaging and developed a bioreactor based on the concept of turbulent flow. Eventually, through the identification of two key fluid physic parameters, turbulent energy and shear stress, we succeeded in scaling up the bioreactor to qualitatively and quantitatively achieve clinically applicable levels. Interestingly, three soluble factors released from imMKCLs in the turbulent flow condition, macrophage migration inhibitory factor (MIF), insulin growth factor binding protein 2 (IGFBP2), and nardilysin (NRDC), enhanced platelet production. Based on these developments, we initiated the first-in-human clinical trial of iPSC-derived platelets to a patient with alloimmune platelet transfusion refractoriness (allo-PTR) using an autologous product. In this review, we detail current research in this field and our study about the ex vivo production of iPSC-derived platelets.
血小板制品用于治疗由造血疾病、化疗、大量出血、体外循环等引起的血小板减少症。其生产依赖于献血志愿者。然而,随着老龄化社会需求的增加和供应的短缺,越来越有必要用其他血液来源加强这一献血系统。此外,血源性感染和同种免疫血小板输注无效问题尚未完全解决。由于人诱导多能干细胞(iPSC)-血小板制品可以独立于供体供应,有望补充当前的血小板制品。基于iPSC的系统的一个大障碍是生产10个单位,相当于2000亿个血小板。为克服这一问题,我们通过将三个转基因c-MYC、BMI1和BCL-XL依次导入源自iPSC的造血和巨核祖细胞阶段细胞,建立了永生化巨核细胞系(imMKCLs)。这三个转基因以Tet-ON方式调控,分别通过添加和去除强力霉素来扩增和成熟imMKCLs。此外,我们成功发现了能在imMKCL培养中实现无饲养层培养条件的药物组合。此外,我们通过活体骨髓成像发现了湍流在血小板生成中的重要性,并基于湍流概念开发了一种生物反应器。最终,通过确定两个关键的流体物理参数,湍流能量和剪切应力,我们成功扩大了生物反应器规模,在质量和数量上达到了临床适用水平。有趣的是,在湍流条件下从imMKCLs释放的三种可溶性因子,巨噬细胞迁移抑制因子(MIF)、胰岛素生长因子结合蛋白2(IGFBP2)和nardilysin(NRDC),增强了血小板生成。基于这些进展,我们使用自体产品对一名同种免疫血小板输注无效(allo-PTR)患者启动了iPSC来源血小板的首次人体临床试验。在本综述中,我们详细介绍了该领域的当前研究以及我们关于iPSC来源血小板体外生产的研究。